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Title 40—Protection of Environment–Volume 25

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Title 40—Protection of Environment–Volume 25
CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
SUBCHAPTER D—WATER PROGRAMS (CONTINUED)
PART 136—GUIDELINES ESTABLISHING TEST PROCEDURES FOR THE ANALYSIS OF POLLUTANTS
§ 136.1 Applicability.
§ 136.2 Definitions.
§ 136.3 Identification of test procedures.
§ 136.4 Application for and approval of alternate test procedures for nationwide use.
§ 136.5 Approval of alternate test procedures for limited use.
§ 136.6 Method modifications and analytical requirements.
§ 136.7 Quality assurance and quality control.
Appendix A to Part 136—Methods for Organic Chemical Analysis of Municipal and Industrial Wastewater
Appendix B to Part 136—Definition and Procedure for the Determination of the Method Detection Limit—Revision 2
Appendix C to Part 136—Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry Method 200.7
Appendix D to Part 136—Precision and Recovery Statements for Methods for Measuring Metals
PART 140—MARINE SANITATION DEVICE STANDARD
§ 140.1 Definitions.
§ 140.2 Scope of standard.
§ 140.3 Standard.
§ 140.4 Complete prohibition.
§ 140.5 Analytical procedures.
PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS
Subpart A—General
§ 141.1 Applicability.
§ 141.2 Definitions.
§ 141.3 Coverage.
§ 141.4 Variances and exemptions.
§ 141.5 Siting requirements.
§ 141.6 Effective dates.
Subpart B—Maximum Contaminant Levels
§ 141.11 Maximum contaminant levels for inorganic chemicals.
§ 141.12 [Reserved]
§ 141.13 Maximum contaminant levels for turbidity.
Subpart C—Monitoring and Analytical Requirements
§ 141.21 Coliform sampling.
§ 141.22 Turbidity sampling and analytical requirements.
§ 141.23 Inorganic chemical sampling and analytical requirements.
§ 141.24 Organic chemicals, sampling and analytical requirements.
§ 141.25 Analytical methods for radioactivity.
§ 141.26 Monitoring frequency and compliance requirements for radionuclides in community water systems.
§ 141.27 Alternate analytical techniques.
§ 141.28 Certified laboratories.
§ 141.29 Monitoring of consecutive public water systems.
Appendix A to Subpart C of Part 141—Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act
Subpart D—Reporting and Recordkeeping
§ 141.31 Reporting requirements.
§ 141.32 [Reserved]
§ 141.33 Record maintenance.
§ 141.34 [Reserved]
§ 141.35 Reporting for unregulated contaminant monitoring results.
Subpart E—Special Regulations, Including Monitoring
§ 141.40 Monitoring requirements for unregulated contaminants.
§ 141.41 Special monitoring for sodium.
§ 141.42 Special monitoring for corrosivity characteristics.
Subpart F—Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals
§ 141.50 Maximum contaminant level goals for organic contaminants.
§ 141.51 Maximum contaminant level goals for inorganic contaminants.
§ 141.52 Maximum contaminant level goals for microbiological contaminants.
§ 141.53 Maximum contaminant level goals for disinfection byproducts.
§ 141.54 Maximum residual disinfectant level goals for disinfectants.
§ 141.55 Maximum contaminant level goals for radionuclides.
Subpart G—National Primary Drinking Water Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels
§ 141.60 Effective dates.
§ 141.61 Maximum contaminant levels for organic contaminants.
§ 141.62 Maximum contaminant levels for inorganic contaminants.
§ 141.63 Maximum contaminant levels (MCLs) for microbiological contaminants.
§ 141.64 Maximum contaminant levels for disinfection byproducts.
§ 141.65 Maximum residual disinfectant levels.
§ 141.66 Maximum contaminant levels for radionuclides.
Subpart H—Filtration and Disinfection
§ 141.70 General requirements.
§ 141.71 Criteria for avoiding filtration.
§ 141.72 Disinfection.
§ 141.73 Filtration.
§ 141.74 Analytical and monitoring requirements.
§ 141.75 Reporting and recordkeeping requirements.
§ 141.76 Recycle provisions.
Subpart I—Control of Lead and Copper
§ 141.80 General requirements.
§ 141.81 Applicability of corrosion control treatment steps to small, medium, and large water systems.
§ 141.82 Description of corrosion control treatment requirements.
§ 141.83 Source water treatment requirements.
§ 141.84 Lead service line replacement requirements.
§ 141.85 Public education and supplemental monitoring and mitigation requirements.
§ 141.86 Monitoring requirements for lead and copper in tap water.
§ 141.87 Monitoring requirements for water quality parameters.
§ 141.88 Monitoring requirements for lead and copper in source water.
§ 141.89 Analytical methods.
§ 141.90 Reporting requirements.
§ 141.91 Recordkeeping requirements.
§ 141.92 Monitoring for lead in schools and child care facilities.
§ 141.93 Small water system compliance flexibility.
Subpart J—Use of Non-Centralized Treatment Devices
§ 141.100 Criteria and procedures for public water systems using point-of-entry devices.
§ 141.101 Use of bottled water.
Subpart K—Treatment Techniques
§ 141.110 General requirements.
§ 141.111 Treatment techniques for acrylamide and epichlorohydrin.
Subpart L—Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors
§ 141.130 General requirements.
§ 141.131 Analytical requirements.
§ 141.132 Monitoring requirements.
§ 141.133 Compliance requirements.
§ 141.134 Reporting and recordkeeping requirements.
§ 141.135 Treatment technique for control of disinfection byproduct (DBP) precursors.
Subparts M-N [Reserved]
Subpart O—Consumer Confidence Reports
§ 141.151 Purpose and applicability of this subpart.
§ 141.152 Effective dates.
§ 141.153 Content of the reports.
§ 141.154 Required additional health information.
§ 141.155 Report delivery and recordkeeping.
Appendix A to Subpart O of Part 141—Regulated Contaminants
Subpart P—Enhanced Filtration and Disinfection—Systems Serving 10,000 or More People
§ 141.170 General requirements.
§ 141.171 Criteria for avoiding filtration.
§ 141.172 Disinfection profiling and benchmarking.
§ 141.173 Filtration.
§ 141.174 Filtration sampling requirements.
§ 141.175 Reporting and recordkeeping requirements.
Subpart Q—Public Notification of Drinking Water Violations
§ 141.201 General public notification requirements.
§ 141.202 Tier 1 Public Notice—Form, manner, and frequency of notice.
§ 141.203 Tier 2 Public Notice—Form, manner, and frequency of notice.
§ 141.204 Tier 3 Public Notice—Form, manner, and frequency of notice.
§ 141.205 Content of the public notice.
§ 141.206 Notice to new billing units or new customers.
§ 141.207 Special notice of the availability of unregulated contaminant monitoring results.
§ 141.208 Special notice for exceedance of the SMCL for fluoride.
§ 141.209 Special notice for nitrate exceedances above MCL by non-community water systems (NCWS), where granted permission by the primacy agency under § 141.11(d).
§ 141.210 Notice by primacy agency on behalf of the public water system.
§ 141.211 Special notice for repeated failure to conduct monitoring of the source water for Cryptosporidium and for failure to determine bin classification or mean Cryptosporidium level.
Appendix A to Subpart Q of Part 141—NPDWR Violations and Other Situations Requiring Public Notice 1
Appendix B to Subpart Q of Part 141—Standard Health Effects Language for Public Notification
Appendix C to Subpart Q of Part 141—List of Acronyms Used in Public Notification Regulation
Subpart R [Reserved]
Subpart S—Ground Water Rule
§ 141.400 General requirements and applicability.
§ 141.401 Sanitary surveys for ground water systems.
§ 141.402 Ground water source microbial monitoring and analytical methods.
§ 141.403 Treatment technique requirements for ground water systems.
§ 141.404 Treatment technique violations for ground water systems.
§ 141.405 Reporting and recordkeeping for ground water systems.
Subpart T—Enhanced Filtration and Disinfection—Systems Serving Fewer Than 10,000 People
General Requirements
§ 141.500 General requirements.
§ 141.501 Who is subject to the requirements of subpart T?
§ 141.502 When must my system comply with these requirements?
§ 141.503 What does subpart T require?
Finished Water Reservoirs
§ 141.510 Is my system subject to the new finished water reservoir requirements?
§ 141.511 What is required of new finished water reservoirs?
Additional Watershed Control Requirements for Unfiltered Systems
§ 141.520 Is my system subject to the updated watershed control requirements?
§ 141.521 What updated watershed control requirements must my unfiltered system implement to continue to avoid filtration?
§ 141.522 How does the State determine whether my system’s watershed control requirements are adequate?
Disinfection Profile
§ 141.530 What is a disinfection profile and who must develop one?
§ 141.531 What criteria must a State use to determine that a profile is unnecessary?
§ 141.532 How does my system develop a disinfection profile and when must it begin?
§ 141.533 What data must my system collect to calculate a disinfection profile?
§ 141.534 How does my system use this data to calculate an inactivation ratio?
§ 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?
§ 141.536 My system has developed an inactivation ratio; what must we do now?
Disinfection Benchmark
§ 141.540 Who has to develop a disinfection benchmark?
§ 141.541 What are significant changes to disinfection practice?
§ 141.542 What must my system do if we are considering a significant change to disinfection practices?
§ 141.543 How is the disinfection benchmark calculated?
§ 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?
Combined Filter Effluent Requirements
§ 141.550 Is my system required to meet subpart T combined filter effluent turbidity limits?
§ 141.551 What strengthened combined filter effluent turbidity limits must my system meet?
§ 141.552 My system consists of “alternative filtration” and is required to conduct a demonstration—what is required of my system and how does the State establish my turbidity limits?
§ 141.553 My system practices lime softening—is there any special provision regarding my combined filter effluent?
Individual Filter Turbidity Requirements
§ 141.560 Is my system subject to individual filter turbidity requirements?
§ 141.561 What happens if my system’s turbidity monitoring equipment fails?
§ 141.562 My system only has two or fewer filters—is there any special provision regarding individual filter turbidity monitoring?
§ 141.563 What follow-up action is my system required to take based on continuous turbidity monitoring?
§ 141.564 My system practices lime softening—is there any special provision regarding my individual filter turbidity monitoring?
Reporting and Recordkeeping Requirements
§ 141.570 What does subpart T require that my system report to the State?
§ 141.571 What records does subpart T require my system to keep?
Subpart U—Initial Distribution System Evaluations
§ 141.600 General requirements.
§ 141.601 Standard monitoring.
§ 141.602 System specific studies.
§ 141.603 40/30 certification.
§ 141.604 Very small system waivers.
§ 141.605 Subpart V compliance monitoring location recommendations.
Subpart V—Stage 2 Disinfection Byproducts Requirements
§ 141.620 General requirements.
§ 141.621 Routine monitoring.
§ 141.622 Subpart V monitoring plan.
§ 141.623 Reduced monitoring.
§ 141.624 Additional requirements for consecutive systems.
§ 141.625 Conditions requiring increased monitoring.
§ 141.626 Operational evaluation levels.
§ 141.627 Requirements for remaining on reduced TTHM and HAA5 monitoring based on subpart L results.
§ 141.628 Requirements for remaining on increased TTHM and HAA5 monitoring based on subpart L results.
§ 141.629 Reporting and recordkeeping requirements.
Subpart W—Enhanced Treatment for Cryptosporidium
General Requirements
§ 141.700 General requirements.
Source Water Monitoring Requirements
§ 141.701 Source water monitoring.
§ 141.702 Sampling schedules.
§ 141.703 Sampling locations.
§ 141.704 Analytical methods.
§ 141.705 Approved laboratories.
§ 141.706 Reporting source water monitoring results.
§ 141.707 Grandfathering previously collected data.
Disinfection Profiling and Benchmarking Requirements
§ 141.708 Requirements when making a significant change in disinfection practice.
§ 141.709 Developing the disinfection profile and benchmark.
Treatment Technique Requirements
§ 141.710 Bin classification for filtered systems.
§ 141.711 Filtered system additional Cryptosporidium treatment requirements.
§ 141.712 Unfiltered system Cryptosporidium treatment requirements.
§ 141.713 Schedule for compliance with Cryptosporidium treatment requirements.
§ 141.714 Requirements for uncovered finished water storage facilities.
Requirements for Microbial Toolbox Components
§ 141.715 Microbial toolbox options for meeting Cryptosporidium treatment requirements.
§ 141.716 Source toolbox components.
§ 141.717 Pre-filtration treatment toolbox components.
§ 141.718 Treatment performance toolbox components.
§ 141.719 Additional filtration toolbox components.
§ 141.720 Inactivation toolbox components.
Reporting and Recordkeeping Requirements
§ 141.721 Reporting requirements.
§ 141.722 Recordkeeping requirements.
Requirements for Sanitary Surveys Performed by EPA
§ 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.
Subpart X—Aircraft Drinking Water Rule
§ 141.800 Applicability and compliance date.
§ 141.801 Definitions.
§ 141.802 Coliform sampling plan.
§ 141.803 Coliform sampling.
§ 141.804 Aircraft water system operations and maintenance plan.
§ 141.805 Notification to passengers and crew.
§ 141.806 Reporting requirements.
§ 141.807 Recordkeeping requirements.
§ 141.808 Audits and inspections.
§ 141.809 Supplemental treatment.
§ 141.810 Violations.
Subpart Y—Revised Total Coliform Rule
§ 141.851 General.
§ 141.852 Analytical methods and laboratory certification.
§ 141.853 General monitoring requirements for all public water systems.
§ 141.854 Routine monitoring requirements for non-community water systems serving 1,000 or fewer people using only ground water.
§ 141.855 Routine monitoring requirements for community water systems serving 1,000 or fewer people using only ground water.
§ 141.856 Routine monitoring requirements for subpart H public water systems serving 1,000 or fewer people.
§ 141.857 Routine monitoring requirements for public water systems serving more than 1,000 people.
§ 141.858 Repeat monitoring and E. coli requirements.
§ 141.859 Coliform treatment technique triggers and assessment requirements for protection against potential fecal contamination.
§ 141.860 Violations.
§ 141.861 Reporting and recordkeeping.
PART 142—NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION
Subpart A—General Provisions
§ 142.1 Applicability.
§ 142.2 Definitions.
§ 142.3 Scope.
§ 142.4 State and local authority.
Subpart B—Primary Enforcement Responsibility
§ 142.10 Requirements for a determination of primary enforcement responsibility.
§ 142.11 Initial determination of primary enforcement responsibility.
§ 142.12 Revision of State programs.
§ 142.13 Public hearing.
§ 142.14 Records kept by States.
§ 142.15 Reports by States.
§ 142.16 Special primacy requirements.
§ 142.17 Review of State programs and procedures for withdrawal of approved primacy programs.
§ 142.18 EPA review of State monitoring determinations.
§ 142.19 EPA review of State implementation of national primary drinking water regulations for lead and copper.
Subpart C—Review of State-Issued Variances and Exemptions
§ 142.20 State-issued variances and exemptions under Section 1415(a) and Section 1416 of the Act.
§ 142.21 State consideration of a variance or exemption request.
§ 142.22 Review of State variances, exemptions and schedules.
§ 142.23 Notice to State.
§ 142.24 Administrator’s rescission.
Subpart D—Federal Enforcement
§ 142.30 Failure by State to assure enforcement.
§ 142.31 [Reserved]
§ 142.32 Petition for public hearing.
§ 142.33 Public hearing.
§ 142.34 Entry and inspection of public water systems.
Subpart E—Variances Issued by the Administrator Under Section 1415(a) of the Act
§ 142.40 Requirements for a variance.
§ 142.41 Variance request.
§ 142.42 Consideration of a variance request.
§ 142.43 Disposition of a variance request.
§ 142.44 Public hearings on variances and schedules.
§ 142.45 Action after hearing.
§ 142.46 Alternative treatment techniques.
Subpart F—Exemptions Issued by the Administrator
§ 142.50 Requirements for an exemption.
§ 142.51 Exemption request.
§ 142.52 Consideration of an exemption request.
§ 142.53 Disposition of an exemption request.
§ 142.54 Public hearings on exemption schedules.
§ 142.55 Final schedule.
§ 142.56 Extension of date for compliance.
§ 142.57 Bottled water, point-of-use, and point-of-entry devices.
Subpart G—Identification of Best Technology, Treatment Techniques or Other Means Generally Available
§ 142.60 Variances from the maximum contaminant level for total trihalomethanes.
§ 142.61 Variances from the maximum contaminant level for fluoride.
§ 142.62 Variances and exemptions from the maximum contaminant levels for organic and inorganic chemicals.
§ 142.63 Variances and exemptions from the maximum contaminant level for total coliforms.
§ 142.64 Variances and exemptions from the requirements of part 141, subpart H—Filtration and Disinfection.
§ 142.65 Variances and exemptions from the maximum contaminant levels for radionuclides.
Subpart H—Indian Tribes
§ 142.72 Requirements for Tribal eligibility.
§ 142.76 Request by an Indian Tribe for a determination of eligibility.
§ 142.78 Procedure for processing an Indian Tribe’s application.
Subpart I—Administrator’s Review of State Decisions that Implement Criteria Under Which Filtration Is Required
§ 142.80 Review procedures.
§ 142.81 Notice to the State.
Subpart J [Reserved]
Subpart K—Variances for Small System
General Provisions
§ 142.301 What is a small system variance?
§ 142.302 Who can issue a small system variance?
§ 142.303 Which size public water systems can receive a small system variance?
§ 142.304 For which of the regulatory requirements is a small system variance available?
§ 142.305 When can a small system variance be granted by a State?
Review of Small System Variance Application
§ 142.306 What are the responsibilities of the public water system, State and the Administrator in ensuring that sufficient information is available and for evaluation of a small system variance application?
§ 142.307 What terms and conditions must be included in a small system variance?
Public Participation
§ 142.308 What public notice is required before a State or the Administrator proposes to issue a small system variance?
§ 142.309 What are the public meeting requirements associated with the proposal of a small system variance?
§ 142.310 How can a person served by the public water system obtain EPA review of a State proposed small system variance?
EPA Review And Approval of Small System Variances
§ 142.311 What procedures allow the Administrator to object to a proposed small system variance or overturn a granted small system variance for a public water system serving 3,300 or fewer persons?
§ 142.312 What EPA action is necessary when a State proposes to grant a small system variance to a public water system serving a population of more than 3,300 and fewer than 10,000 persons?
§ 142.313 How will the Administrator review a State’s program under this subpart?
PART 143—OTHER SAFE DRINKING WATER ACT REGULATIONS
Subpart A—National Secondary Drinking Water Regulations
§ 143.1 Purpose.
§ 143.2 Definitions.
§ 143.3 Secondary maximum contaminant levels.
§ 143.4 Monitoring.
§§ 143.5-143.9 [Reserved]
Subpart B—Use of Lead Free Pipes, Fittings, Fixtures, Solder, and Flux for Drinking Water
§ 143.10 Applicability and scope.
§ 143.11 Definitions.
§ 143.12 Definition of lead free and calculation methodology.
§ 143.13 Use prohibitions.
§ 143.14 State enforcement of use prohibitions.
§ 143.15 Introduction into commerce prohibitions.
§ 143.16 Exemptions.
§ 143.17 [Reserved]
§ 143.18 Required labeling of solder and flux that is not lead free.
§ 143.19 Required certification of products.
§ 143.20 Compliance provisions.
PART 144—UNDERGROUND INJECTION CONTROL PROGRAM
Subpart A—General Provisions
§ 144.1 Purpose and scope of part 144.
§ 144.2 Promulgation of Class II programs for Indian lands.
§ 144.3 Definitions.
§ 144.4 Considerations under Federal law.
§ 144.5 Confidentiality of information.
§ 144.6 Classification of wells.
§ 144.7 Identification of underground sources of drinking water and exempted aquifers.
§ 144.8 Noncompliance and program reporting by the Director.
Subpart B—General Program Requirements
§ 144.11 Prohibition of unauthorized injection.
§ 144.12 Prohibition of movement of fluid into underground sources of drinking water.
§ 144.13 Prohibition of Class IV wells.
§ 144.14 Requirements for wells injecting hazardous waste.
§ 144.15 Prohibition of non-experimental Class V wells for geologic sequestration.
§ 144.16 Waiver of requirement by Director.
§ 144.17 Records.
§ 144.18 Requirements for Class VI wells.
§ 144.19 Transitioning from Class II to Class VI.
Subpart C—Authorization of Underground Injection by Rule
§ 144.21 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells.
§ 144.22 Existing Class II enhanced recovery and hydrocarbon storage wells.
§ 144.23 Class IV wells.
§ 144.24 Class V wells.
§ 144.25 Requiring a permit.
§ 144.26 Inventory requirements.
§ 144.27 Requiring other information.
§ 144.28 Requirements for Class I, II, and III wells authorized by rule.
Subpart D—Authorization by Permit
§ 144.31 Application for a permit; authorization by permit.
§ 144.32 Signatories to permit applications and reports.
§ 144.33 Area permits.
§ 144.34 Emergency permits.
§ 144.35 Effect of a permit.
§ 144.36 Duration of permits.
§ 144.37 Continuation of expiring permits.
§ 144.38 Transfer of permits.
§ 144.39 Modification or revocation and reissuance of permits.
§ 144.40 Termination of permits.
§ 144.41 Minor modifications of permits.
Subpart E—Permit Conditions
§ 144.51 Conditions applicable to all permits.
§ 144.52 Establishing permit conditions.
§ 144.53 Schedule of compliance.
§ 144.54 Requirements for recording and reporting of monitoring results.
§ 144.55 Corrective action.
Subpart F—Financial Responsibility: Class I Hazardous Waste Injection Wells
§ 144.60 Applicability.
§ 144.61 Definitions of terms as used in this subpart.
§ 144.62 Cost estimate for plugging and abandonment.
§ 144.63 Financial assurance for plugging and abandonment.
§ 144.64 Incapacity of owners or operators, guarantors, or financial institutions.
§ 144.65 Use of State-required mechanisms.
§ 144.66 State assumption of responsibility.
§ 144.70 Wording of the instruments.
Subpart G—Requirements for Owners and Operators of Class V Injection Wells
§ 144.79 General.
Definition of Class V Injection Wells
§ 144.80 What is a Class V injection well?
§ 144.81 Does this subpart apply to me?
Requirements for All Class V Injection Wells
§ 144.82 What must I do to protect underground sources of drinking water?
§ 144.83 Do I need to notify anyone about my Class V injection well?
§ 144.84 Do I need to get a permit?
Additional Requirements for Class V Large-Capacity Cesspools and Motor Vehicle Waste Disposal Wells
§ 144.85 Do these additional requirements apply to me?
§ 144.86 What are the definitions I need to know?
§ 144.87 How does the identification of ground water protection areas and other sensitive ground water areas affect me?
§ 144.88 What are the additional requirements?
§ 144.89 How do I close my Class V injection well?
PART 145—STATE UIC PROGRAM REQUIREMENTS
Subpart A—General Program Requirements
§ 145.1 Purpose and scope.
§ 145.2 Definitions.
Subpart B—Requirements for State Programs
§ 145.11 Requirements for permitting.
§ 145.12 Requirements for compliance evaluation programs.
§ 145.13 Requirements for enforcement authority.
§ 145.14 Sharing of information.
Subpart C—State Program Submissions
§ 145.21 General requirements for program approvals.
§ 145.22 Elements of a program submission.
§ 145.23 Program description.
§ 145.24 Attorney General’s statement.
§ 145.25 Memorandum of Agreement with the Regional Administrator.
Subpart D—Program Approval, Revision and Withdrawal
§ 145.31 Approval process.
§ 145.32 Procedures for revision of State programs.
§ 145.33 Criteria for withdrawal of State programs.
§ 145.34 Procedures for withdrawal of State programs.
Subpart E—Indian Tribes
§ 145.52 Requirements for Tribal eligibility.
§ 145.56 Request by an Indian Tribe for a determination of eligibility.
§ 145.58 Procedure for processing an Indian Tribe’s application.
PART 146—UNDERGROUND INJECTION CONTROL PROGRAM: CRITERIA AND STANDARDS
Subpart A—General Provisions
§ 146.1 Applicability and scope.
§ 146.2 Law authorizing these regulations.
§ 146.3 Definitions.
§ 146.4 Criteria for exempted aquifers.
§ 146.5 Classification of injection wells.
§ 146.6 Area of review.
§ 146.7 Corrective action.
§ 146.8 Mechanical integrity.
§ 146.9 Criteria for establishing permitting priorities.
§ 146.10 Plugging and abandoning Class I, II, III, IV, and V wells.
Subpart B—Criteria and Standards Applicable to Class I Wells
§ 146.11 Criteria and standards applicable to Class I nonhazardous wells.
§ 146.12 Construction requirements.
§ 146.13 Operating, monitoring and reporting requirements.
§ 146.14 Information to be considered by the Director.
§ 146.15 Class I municipal disposal well alternative authorization in certain parts of Florida.
§ 146.16 Requirements for new Class I municipal wells in certain parts of Florida.
Subpart C—Criteria and Standards Applicable to Class II Wells
§ 146.21 Applicability.
§ 146.22 Construction requirements.
§ 146.23 Operating, monitoring, and reporting requirements.
§ 146.24 Information to be considered by the Director.
Subpart D—Criteria and Standards Applicable to Class III Wells
§ 146.31 Applicability.
§ 146.32 Construction requirements.
§ 146.33 Operating, monitoring, and reporting requirements.
§ 146.34 Information to be considered by the Director.
Subpart E—Criteria and Standards Applicable to Class IV Injection Wells [Reserved]
Subpart F—Criteria and Standards Applicable to Class V Injection Wells
§ 146.51 Applicability.
Subpart G—Criteria and Standards Applicable to Class I Hazardous Waste Injection Wells
§ 146.61 Applicability.
§ 146.62 Minimum criteria for siting.
§ 146.63 Area of review.
§ 146.64 Corrective action for wells in the area of review.
§ 146.65 Construction requirements.
§ 146.66 Logging, sampling, and testing prior to new well operation.
§ 146.67 Operating requirements.
§ 146.68 Testing and monitoring requirements.
§ 146.69 Reporting requirements.
§ 146.70 Information to be evaluated by the Director.
§ 146.71 Closure.
§ 146.72 Post-closure care.
§ 146.73 Financial responsibility for post-closure care.
Subpart H—Criteria and Standards Applicable to Class VI Wells
§ 146.81 Applicability.
§ 146.82 Required Class VI permit information.
§ 146.83 Minimum criteria for siting.
§ 146.84 Area of review and corrective action.
§ 146.85 Financial responsibility.
§ 146.86 Injection well construction requirements.
§ 146.87 Logging, sampling, and testing prior to injection well operation.
§ 146.88 Injection well operating requirements.
§ 146.89 Mechanical integrity.
§ 146.90 Testing and monitoring requirements.
§ 146.91 Reporting requirements.
§ 146.92 Injection well plugging.
§ 146.93 Post-injection site care and site closure.
§ 146.94 Emergency and remedial response.
§ 146.95 Class VI injection depth waiver requirements.
PART 147—STATE, TRIBAL, AND EPA-ADMINISTERED UNDERGROUND INJECTION CONTROL PROGRAMS
Subpart A—General Provisions
§ 147.1 Purpose and scope.
§ 147.2 Severability of provisions.
Subpart B—Alabama
§ 147.50 State-administered program—Class II wells.
§ 147.51 State-administered program—Class I, III, IV, and V wells.
§ 147.52 State-administered program—Hydraulic Fracturing of Coal Beds.
§ 147.60 EPA-administered program—Indian lands.
Subpart C—Alaska
§ 147.100 State-administered program—Class II wells.
§ 147.101 EPA-administered program.
§ 147.102 Aquifer exemptions.
§ 147.103 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
§ 147.104 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
Subpart D—Arizona
§ 147.150 State-administered program. [Reserved]
§ 147.151 EPA-administered program.
§ 147.152 Aquifer exemptions. [Reserved]
Subpart E—Arkansas
§ 147.200 State-administered program—Class I, III, IV, and V wells.
§ 147.201 State-administered program—Class II wells. [Reserved]
§ 147.205 EPA-administered program—Indian lands.
Subpart F—California
§ 147.250 State-administered program—Class II wells.
§ 147.251 EPA-administered program—Class I, III, IV and V wells and Indian lands.
§ 147.252 Aquifer exemptions. [Reserved]
§ 147.253 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
Subpart G—Colorado
§ 147.300 State-administered program—Class II wells.
§ 147.301 EPA-administered program—Class I, III, IV, V wells and Indian lands.
§ 147.302 Aquifer exemptions.
§ 147.303 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
§ 147.304 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
§ 147.305 Requirements for all wells.
Subpart H—Connecticut
§ 147.350 State-administered program.
§§ 147.351-147.352 [Reserved]
§ 147.353 EPA-administered program—Indian lands.
§§ 147.354-147.359 [Reserved]
Subpart I—Delaware
§ 147.400 State-administered program.
§§ 147.401-147.402 [Reserved]
§ 147.403 EPA-administered program—Indian lands.
§§ 147.404-147.449 [Reserved]
Subpart J—District of Columbia
§ 147.450 State-administered program. [Reserved]
§ 147.451 EPA-administered program.
§ 147.452 Aquifer exemptions. [Reserved]
Subpart K—Florida
§ 147.500 State-administered program—Class I, III, IV, and V wells.
§ 147.501 EPA-administered program—Class II wells and Indian lands.
§ 147.502 Aquifer exemptions. [Reserved]
§ 147.503 Existing Class II (except enhanced recovery and hydrocarbon storage) wells authorized by rule.
§ 147.504 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
Subpart L—Georgia
§ 147.550 State-administered program.
§§ 147.551-147.552 [Reserved]
§ 147.553 EPA-administered program—Indian lands.
§§ 147.554-147.559 [Reserved]
Subpart M—Hawaii
§ 147.600 State-administered program. [Reserved]
§ 147.601 EPA-administered program.
Subpart N—Idaho
§ 147.650 State-administered program—Class I, III, IV, and V wells.
§ 147.651 EPA-administered program—Class II wells and all wells on Indian lands.
§ 147.652 Aquifer exemptions. [Reserved]
Subpart O—Illinois
§ 147.700 State-administered program—Class I, III, IV, and V wells.
§ 147.701 State-administered program—Class II wells.
§ 147.703 EPA-administered program—Indian lands.
Subpart P—Indiana
§ 147.750 State-administered program—Class II wells.
§ 147.751 EPA-administered program.
§ 147.752 Aquifer exemptions. [Reserved]
§ 147.753 Existing Class I and III wells authorized by rule.
Subpart Q—Iowa
§ 147.800 State-administered program. [Reserved]
§ 147.801 EPA-administered program.
§ 147.802 Aquifer exemptions. [Reserved]
Subpart R—Kansas
§ 147.850 State-administered program—Class I, III, IV and V wells.
§ 147.851 State-administered program—Class II wells.
§§ 147.852-147.859 [Reserved]
§ 147.860 EPA-administered program—Indian lands.
Subpart S—Kentucky
§ 147.900 State-administered program—Class II wells.
§ 147.901 EPA-administered program—Class I, III, IV, V, and VI wells and Indian lands.
§ 147.902 Acquifer exemptions.
§ 147.903 Existing Class I and III wells authorized by rule.
§ 147.904 [Reserved]
§ 147.905 Requirements for all wells—area of review.
Subpart T—Louisiana
§ 147.950 State-administered program—Class I, II, III, IV, V and VI wells.
§ 147.951 EPA-administered program—Indian lands.
Subpart U—Maine
§ 147.1000 State-administered program.
§ 147.1001 EPA-administered program—Indian lands.
Subpart V—Maryland
§ 147.1050 State-administered program—Class I, II, III, IV, and V wells.
§§ 147.1051-147.1052 [Reserved]
§ 147.1053 EPA-administered program—Indian lands.
§§ 147.1054-147.1099 [Reserved]
Subpart W—Massachusetts
§ 147.1100 State-administered program.
§ 147.1101 EPA-administered program—Indian lands.
Subpart X—Michigan
§ 147.1150 State-administered program—Class II wells.
§ 147.1151 EPA-administered program—Class I, III, IV, V, and VI wells and Indian country.
§ 147.1152 Aquifer exemptions. [Reserved]
§ 147.1153 Existing Class II disposal wells authorized by rule in Indian country.
§ 147.1154 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule in Indian country.
§ 147.1155 Requirements for all EPA-administered wells.
Subpart Y—Minnesota
§ 147.1200 State-administered program. [Reserved]
§ 147.1201 EPA-administered program.
§ 147.1202 Aquifer exemptions. [Reserved]
§ 147.1210 Requirements for Indian lands.
Subpart Z—Mississippi
§ 147.1250 State-administered program—Class I, III, IV, and V wells.
§ 147.1251 State-administered program—Class II wells.
§ 147.1252 EPA-administered program—Indian lands.
Subpart AA—Missouri
§ 147.1300 State-administered program.
§ 147.1301 State-administered program—Class I, III, IV, and V wells.
§ 147.1302 Aquifer exemptions. [Reserved]
§ 147.1303 EPA-administered program—Indian lands.
Subpart BB—Montana
§ 147.1350 State-administered programs—Class II wells.
§ 147.1351 EPA-administered program.
§ 147.1352 Aquifer exemptions.
§ 147.1353 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
§ 147.1354 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
§ 147.1355 Requirements for all wells.
Appendix A to Subpart BB of Part 147—State Requirements Incorporated by Reference in Subpart BB of Part 147 of the Code of Federal Regulations
Subpart CC—Nebraska
§ 147.1400 State-administered program—Class II wells.
§ 147.1401 State administered program—Class I, III, IV and V wells.
§ 147.1402 Aquifer exemptions. [Reserved]
§ 147.1403 EPA-administered program—Indian lands.
Subpart DD—Nevada
§ 147.1450 State-administered program.
§ 147.1451 EPA administered program—Indian lands.
§ 147.1452 Aquifer exemptions. [Reserved]
§ 147.1453 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
§ 147.1454 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
Subpart EE—New Hampshire
§ 147.1500 State-administered program.
§ 147.1501 EPA-administered program—Indian lands.
Subpart FF—New Jersey
§ 147.1550 State-administered program.
§ 147.1551 EPA-administered program—Indian lands.
Subpart GG—New Mexico
§ 147.1600 State-administered program—Class II wells.
§ 147.1601 State-administered program—Class I, III, IV and V wells.
§ 147.1603 EPA-administered program—Indian lands.
Subpart HH—New York
§ 147.1650 State-administered program. [Reserved]
§ 147.1651 EPA-administered program.
§ 147.1652 Aquifer exemptions.
§ 147.1653 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
§ 147.1654 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
§ 147.1655 Requirements for wells authorized by permit.
Subpart II—North Carolina
§ 147.1700 State-administered program.
§§ 147.1701-147.1702 [Reserved]
§ 147.1703 EPA-administered program—Indian lands.
§§ 147.1704-147.1749 [Reserved]
Subpart JJ—North Dakota
§ 147.1750 State-administered program—Class II wells.
§ 147.1751 State-administered program—Class I, III, IV, V and VI wells.
§ 147.1752 EPA-administered program—Indian lands.
Subpart KK—Ohio
§ 147.1800 State-administered program—Class II wells.
§ 147.1801 State-administered program—Class I, III, IV and V wells.
§ 147.1802 Aquifer exemptions. [Reserved]
§ 147.1803 Existing Class I and III wells authorized by rule—maximum injection pressure.
§ 147.1805 EPA-administered program—Indian lands.
Subpart LL—Oklahoma
§ 147.1850 State-administered program—Class I, III, IV and V wells.
§ 147.1851 State-administered program—Class II wells.
§ 147.1852 EPA-administered program—Indian lands.
Subpart MM—Oregon
§ 147.1900 State-administered program.
§ 147.1901 EPA-administered program—Indian lands.
Subpart NN—Pennsylvania
§ 147.1950 State-administered program. [Reserved]
§ 147.1951 EPA-administered program.
§ 147.1952 Aquifer exemptions.
§ 147.1953 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
§ 147.1954 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
§ 147.1955 Requirements for wells authorized by permit.
Subpart OO—Rhode Island
§ 147.2000 State-administered program—Class I, II, III, IV, and V wells.
§ 147.2001 EPA-administered program—Indian lands.
Subpart PP—South Carolina
§ 147.2050 State-administered program.
§ 147.2051 EPA-administered program—Indian lands.
Subpart QQ—South Dakota
§ 147.2100 State-administered program—Class II wells.
§ 147.2101 EPA-administered program—Class I, III, IV and V wells and all wells on Indian lands.
§ 147.2102 Aquifer exemptions.
§ 147.2103 Existing Class II enhanced recovery and hydrocarbon storage wells authorized by rule.
§ 147.2104 Requirements for all wells.
Subpart RR—Tennessee
§ 147.2150 State-administered program—Class I, II, III, IV, and V wells.
§ 147.2151 EPA-administered program Class IV and Indian lands.
§ 147.2152 Aquifer exemptions. [Reserved]
§ 147.2153 Existing Class I, II (except enhanced recovery and hydrocarbon storage) and III wells authorized by rule.
Subpart SS—Texas
§ 147.2200 State-administered program—Class I, III, IV, and V wells.
§ 147.2201 State-administered program—Class II wells.
§ 147.2205 EPA-administered program—Indian lands.
Subpart TT—Utah
§ 147.2250 State-administered program—Class I, III, IV, and V wells.
§ 147.2251 State-administered program—Class II wells.
§ 147.2253 EPA-administered program—Indian lands.
Subpart UU—Vermont
§ 147.2300 State-administered program.
§§ 147.2301-147.2302 [Reserved]
§ 147.2303 EPA-administered program—Indian lands.
§§ 147.2304-147.2349 [Reserved]
Subpart VV—Virginia
§ 147.2350 State-administered program. [Reserved]
§ 147.2351 EPA-administered program.
§ 147.2352 Aquifer exemptions. [Reserved]
Subpart WW—Washington
§ 147.2400 State-administered program—Class I, II, III, IV, and V wells.
§ 147.2403 EPA-administered program—Indian lands.
§ 147.2404 EPA-administered program—Colville Reservation.
Subpart XX—West Virginia
§§ 147.2450-147.2452 [Reserved]
§ 147.2453 EPA-administered program—Indian lands.
§§ 147.2454-147.2499 [Reserved]
Subpart YY—Wisconsin
§ 147.2500 State-administered program.
§ 147.2510 EPA-administered program—Indian lands.
Subpart ZZ—Wyoming
§ 147.2550 State-administered program—Class I, III, IV, V and VI wells.
§ 147.2551 State-administered program—Class II wells.
§ 147.2553 EPA-administered program—Indian lands.
§ 147.2554 Aquifer exemptions.
§ 147.2555 Aquifer exemptions since January 1, 1999.
Subpart AAA—Guam
§ 147.2600 State-administered program.
§ 147.2601 EPA-administered program—Indian lands.
Subpart BBB—Puerto Rico
§ 147.2650 State-administered program—Class I, II, III, IV, and V wells.
§ 147.2651 EPA-administered program—Indian lands.
Subpart CCC—Virgin Islands
§ 147.2700 State-administered program. [Reserved]
§ 147.2701 EPA-administered program.
Subpart DDD—American Samoa
§ 147.2750 State-administered program. [Reserved]
§ 147.2751 EPA-administered program.
§ 147.2752 Aquifer exemptions. [Reserved]
Subpart EEE—Commonwealth of the Northern Mariana Islands
§ 147.2800 State-administered program—Class I, II, III, IV, and V wells.
§ 147.2801 EPA-administered program.
§ 147.2802 Aquifer exemptions. [Reserved]
Subpart FFF—Trust Territory of the Pacific Islands
§ 147.2850 State-administered program. [Reserved]
§ 147.2851 EPA-administered program.
§ 147.2852 Aquifer exemptions. [Reserved]
Subpart GGG—Osage Mineral Reserve—Class II Wells
§ 147.2901 Applicability and scope.
§ 147.2902 Definitions.
§ 147.2903 Prohibition of unauthorized injection.
§ 147.2904 Area of review.
§ 147.2905 Plugging and abandonment.
§ 147.2906 Emergency permits.
§ 147.2907 Confidentiality of information.
§ 147.2908 Aquifer exemptions.
§ 147.2909 Authorization of existing wells by rule.
§ 147.2910 Duration of authorization by rule.
§ 147.2911 Construction requirements for wells authorized by rule.
§ 147.2912 Operating requirements for wells authorized by rule.
§ 147.2913 Monitoring and reporting requirements for wells authorized by rule.
§ 147.2914 Corrective action for wells authorized by rule.
§ 147.2915 Requiring a permit for wells authorized by rule.
§ 147.2916 Coverage of permitting requirements.
§ 147.2917 Duration of permits.
§ 147.2918 Permit application information.
§ 147.2919 Construction requirements for wells authorized by permit.
§ 147.2920 Operating requirements for wells authorized by permit.
§ 147.2921 Schedule of compliance.
§ 147.2922 Monitoring and reporting requirements for wells authorized by permit.
§ 147.2923 Corrective action for wells authorized by permit.
§ 147.2924 Area permits.
§ 147.2925 Standard permit conditions.
§ 147.2926 Permit transfers.
§ 147.2927 Permit modification.
§ 147.2928 Permit termination.
§ 147.2929 Administrative permitting procedures.
Subpart HHH—Lands of the Navajo, Ute Mountain Ute, and All Other New Mexico Tribes
§ 147.3000 EPA-administered program.
§ 147.3001 Definition.
§ 147.3002 Public notice of permit actions.
§ 147.3003 Aquifer exemptions.
§ 147.3004 Duration of rule authorization for existing Class I and III wells.
§ 147.3005 Radioactive waste injection wells.
§ 147.3006 Injection pressure for existing Class II wells authorized by rule.
§ 147.3007 Application for a permit.
§ 147.3008 Criteria for aquifer exemptions.
§ 147.3009 Area of review.
§ 147.3010 Mechanical integrity tests.
§ 147.3011 Plugging and abandonment of Class III wells.
§ 147.3012 Construction requirements for Class I wells.
§ 147.3013 Information to be considered for Class I wells.
§ 147.3014 Construction requirements for Class III wells.
§ 147.3015 Information to be considered for Class III wells.
§ 147.3016 Criteria and standards applicable to Class V wells.
Appendix A to Subpart HHH of Part 147—Exempted Aquifers in New Mexico
Subpart III—Lands of Certain Oklahoma Indian Tribes
§ 147.3100 EPA-administered program.
§ 147.3101 Public notice of permit actions.
§ 147.3102 Plugging and abandonment plans.
§ 147.3103 Fluid seals.
§ 147.3104 Notice of abandonment.
§ 147.3105 Plugging and abandonment report.
§ 147.3106 Area of review.
§ 147.3107 Mechanical integrity.
§ 147.3108 Plugging Class I, II, and III wells.
§ 147.3109 Timing of mechanical integrity test.
Subpart JJJ—Assiniboine and Sioux Tribes
§ 147.3200 Fort Peck Indian Reservation: Assiniboine & Sioux Tribes—Class II wells.
Subpart KKK [Reserved]
Subpart LLL—Navajo Indian Lands
§ 147.3400 Navajo Indian lands—Class II wells.
PART 148—HAZARDOUS WASTE INJECTION RESTRICTIONS
Subpart A—General
§ 148.1 Purpose, scope and applicability.
§ 148.2 Definitions.
§ 148.3 Dilution prohibited as a substitute for treatment.
§ 148.4 Procedures for case-by-case extensions to an effective date.
§ 148.5 Waste analysis.
Subpart B—Prohibitions on Injection
§ 148.10 Waste specific prohibitions—solvent wastes.
§ 148.11 Waste specific prohibitions—dioxin-containing wastes.
§ 148.12 Waste specific prohibitions—California list wastes.
§ 148.14 Waste specific prohibitions—first third wastes.
§ 148.15 Waste specific prohibitions—second third wastes.
§ 148.16 Waste specific prohibitions—third third wastes.
§ 148.17 Waste specific prohibitions; newly listed wastes.
§ 148.18 Waste specific prohibitions—newly listed and identified wastes.
Subpart C—Petition Standards and Procedures
§ 148.20 Petitions to allow injection of a waste prohibited under subpart B.
§ 148.21 Information to be submitted in support of petitions.
§ 148.22 Requirements for petition submission, review and approval or denial.
§ 148.23 Review of exemptions granted pursuant to a petition.
§ 148.24 Termination of approved petition.
PART 149—SOLE SOURCE AQUIFERS
Subpart A—Criteria for Identifying Critical Aquifer Protection Areas
§ 149.1 Purpose.
§ 149.2 Definitions.
§ 149.3 Critical Aquifer Protection Areas.
Subpart B—Review of Projects Affecting the Edwards Underground Reservoir, A Designated Sole Source Aquifer in the San Antonio, Texas Area
§ 149.100 Applicability.
§ 149.101 Definitions.
§ 149.102 Project review authority.
§ 149.103 Public information.
§ 149.104 Submission of petitions.
§ 149.105 Decision to review.
§ 149.106 Notice of review.
§ 149.107 Request for information.
§ 149.108 Public hearing.
§ 149.109 Decision under section 1424(e).
§ 149.110 Resubmittal of redesigned projects.
§ 149.111 Funding to redesigned projects.

Title 40—Protection of Environment–Volume 25


Part


chapter i—Environmental Protection Agency (Continued)

136

CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

SUBCHAPTER D—WATER PROGRAMS (CONTINUED)

PART 136—GUIDELINES ESTABLISHING TEST PROCEDURES FOR THE ANALYSIS OF POLLUTANTS


Authority:Secs. 301, 304(h), 307 and 501(a), Pub. L. 95-217, 91 Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (the Federal Water Pollution Control Act Amendments of 1972 as amended by the Clean Water Act of 1977).

§ 136.1 Applicability.

(a) The procedures prescribed herein shall, except as noted in §§ 136.4, 136.5, and 136.6, be used to perform the measurements indicated whenever the waste constituent specified is required to be measured for:


(1) An application submitted to the Director and/or reports required to be submitted under NPDES permits or other requests for quantitative or qualitative effluent data under parts 122 through 125 of this chapter; and


(2) Reports required to be submitted by dischargers under the NPDES established by parts 124 and 125 of this chapter; and


(3) Certifications issued by States pursuant to section 401 of the Clean Water Act (CWA), as amended.


(b) The procedure prescribed herein and in part 503 of title 40 shall be used to perform the measurements required for an application submitted to the Administrator or to a State for a sewage sludge permit under section 405(f) of the Clean Water Act and for recordkeeping and reporting requirements under part 503 of title 40.


(c) For the purposes of the NPDES program, when more than one test procedure is approved under this part for the analysis of a pollutant or pollutant parameter, the test procedure must be sufficiently sensitive as defined at 40 CFR 122.21(e)(3) and 122.44(i)(1)(iv).


[72 FR 14224, Mar. 26, 2007, as amended at 77 FR 29771, May 18, 2012; 79 FR 49013, Aug. 19, 2014; 82 FR 40846, Aug. 28, 2017]


§ 136.2 Definitions.

As used in this part, the term:


(a) Act means the Clean Water Act of 1977, Pub. L. 95-217, 91 Stat. 1566, et seq. (33 U.S.C. 1251 et seq.) (The Federal Water Pollution Control Act Amendments of 1972 as amended by the Clean Water Act of 1977).


(b) Administrator means the Administrator of the U.S. Environmental Protection Agency.


(c) Regional Administrator means one of the EPA Regional Administrators.


(d) Director means the director as defined in 40 CFR 122.2.


(e) National Pollutant Discharge Elimination System (NPDES) means the national system for the issuance of permits under section 402 of the Act and includes any State or interstate program which has been approved by the Administrator, in whole or in part, pursuant to section 402 of the Act.


(f) Detection limit means the minimum concentration of an analyte (substance) that can be measured and reported with a 99% confidence that the analyte concentration is distinguishable from the method blank results as determined by the procedure set forth at appendix B of this part.


[38 FR 28758, Oct. 16, 1973, as amended at 49 FR 43250, Oct. 26, 1984; 82 FR 40846, Aug. 28, 2017]


§ 136.3 Identification of test procedures.

(a) Parameters or pollutants, for which methods are approved, are listed together with test procedure descriptions and references in Tables IA, IB, IC, ID, IE, IF, IG, and IH of this section. The methods listed in Tables IA, IB, IC, ID, IE, IF, IG, and IH are incorporated by reference, see paragraph (b) of this section, with the exception of EPA Methods 200.7, 601-613, 624.1, 625.1, 1613, 1624, and 1625. The full texts of Methods 601-613, 624.1, 625.1, 1613, 1624, and 1625 are printed in appendix A of this part, and the full text of Method 200.7 is printed in appendix C of this part. The full text for determining the method detection limit when using the test procedures is given in appendix B of this part. In the event of a conflict between the reporting requirements of 40 CFR parts 122 and 125 and any reporting requirements associated with the methods listed in these tables, the provisions of 40 CFR parts 122 and 125 are controlling and will determine a permittee’s reporting requirements. The full texts of the referenced test procedures are incorporated by reference into Tables IA, IB, IC, ID, IE, IF, IG, and IH. The date after the method number indicates the latest editorial change of the method. The discharge parameter values for which reports are required must be determined by one of the standard analytical test procedures incorporated by reference and described in Tables IA, IB, IC, ID, IE, IF, IG, and IH or by any alternate test procedure which has been approved by the Administrator under the provisions of paragraph (d) of this section and §§ 136.4 and 136.5. Under certain circumstances (paragraph (c) of this section, § 136.5(a) through (d) or 40 CFR 401.13,) other additional or alternate test procedures may be used.


Table IA—List of Approved Biological Methods for Wastewater and Sewage Sludge

Parameter and units
Method
1
EPA
Standard methods
AOAC, ASTM, USGS
Other
Bacteria
1. Coliform (fecal), number per 100 mL or number per gram dry weightMost Probable Number (MPN), 5 tube, 3 dilution, orp. 132,3 1680,11 15 1681 11 209221 E-2014
Membrane filter (MF) 2 5, single stepp. 124 39222 D-2015 29B-0050-85 4
2. Coliform (fecal), number per 100 mLMPN, 5 tube, 3 dilution, orp. 132 39221 E-2014; 9221 F-2014 33
Multiple tube/multiple well, orColilert-18®.13 18 28
MF 2 5, single step 5p. 124 39222 D-2015 29
3. Coliform (total), number per 100 mLMPN, 5 tube, 3 dilution, orp. 114 39221 B-2014
MF 2 5, single step or two stepp. 108 39222 B-2015 30B-0025-85 4
MF 2 5, with enrichmentp. 111 39222 B-2015 30
4. E. coli, number per 100 mLMPN 6 8 16 multiple tube, or9221 B2014/9221 F-2014 12 14 33
multiple tube/multiple well, or9223 B-2016 13991.15 10Colilert® 13 18

Colilert-18® 13 17 18
MF 2 5 6 7 8, two step, or9222 B-2015/9222 I-2015 31
Single step1603 21m-ColiBlue24®.19
5. Fecal streptococci, number per 100 mLMPN, 5 tube, 3 dilution, orp. 139 39230 B-2013
MF 2, orp. 136 39230 C-2013 32B-0055-85 4
Plate countp. 143 3
6. Enterococci, number per 100 mLMPN, 5 tube, 3 dilution, orp. 139 39230 B-2013
MPN 6 8, multiple tube/multiple well, or9230 D-2013D6503-99 9Enterolert®.13 23
MF 2 5 6 7 8 single step or1600 249230 C-2013 32
Plate countp. 143 3
7. Salmonella, number per gram dry weight 11MPN multiple tube1682 22
Aquatic Toxicity
8. Toxicity, acute, fresh water organisms, LC50, percent effluentWater flea, Cladoceran, Ceriodaphnia dubia acute2002.0 25
Water fleas, Cladocerans, Daphnia pulex and Daphnia magna acute2021.0 25
Fish, Fathead minnow, Pimephales promelas, and Bannerfin shiner, Cyprinella leedsi, acute2000.0 25
Fish, Rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, acute2019.0 25
9. Toxicity, acute, estuarine and marine organisms of the Atlantic Ocean and Gulf of Mexico, LC50, percent effluentMysid, Mysidopsis bahia, acute2007.0 25.
Fish, Sheepshead minnow, Cyprinodon variegatus, acute2004.0 25
Fish, Silverside, Menidia beryllina, Menidia menidia, and Menidia peninsulae, acute.2006.0 25.
10. Toxicity, chronic, fresh water organisms, NOEC or IC25, percent effluentFish, Fathead minnow, Pimephales promelas, larval survival and growth1000.0 26
Fish, Fathead minnow, Pimephales promelas, embryo-larval survival and teratogenicity1001.0 26
Water flea, Cladoceran, Ceriodaphnia dubia, survival and reproduction1002.0 26
Green alga, Selenastrum capricornutum, growth1003.0 26
11. Toxicity, chronic, estuarine and marine organisms of the Atlantic Ocean and Gulf of Mexico, NOEC or IC25, percent effluentFish, Sheepshead minnow, Cyprinodon variegatus, larval survival and growth1004.0 27.
Fish, Sheepshead minnow, Cyprinodon variegatus, embryo-larval survival and teratogenicity1005.0 27
Fish, Inland silverside, Menidia beryllina, larval survival and growth1006.0 27
Mysid, Mysidopsis bahia, survival, growth, and fecundity1007.0 27
Sea urchin, Arbacia punctulata, fertilization1008.0 27

Table IA notes:


1 The method must be specified when results are reported.


2 A 0.45-µm membrane filter (MF) or other pore size certified by the manufacturer to fully retain organisms to be cultivated and to be free of extractables which could interfere with their growth.


3 Microbiological Methods for Monitoring the Environment, Water and Wastes, EPA/600/8-78/017. 1978. U.S. EPA.


4 U.S. Geological Survey Techniques of Water-Resource Investigations, Book 5, Laboratory Analysis, Chapter A4, Methods for Collection and Analysis of Aquatic Biological and Microbiological Samples. 1989. USGS.


5 Because the MF technique usually yields low and variable recovery from chlorinated wastewaters, the Most Probable Number method will be required to resolve any controversies.


6 Tests must be conducted to provide organism enumeration (density). Select the appropriate configuration of tubes/filtrations and dilutions/volumes to account for the quality, character, consistency, and anticipated organism density of the water sample.


7 When the MF method has been used previously to test waters with high turbidity, large numbers of noncoliform bacteria, or samples that may contain organisms stressed by chlorine, a parallel test should be conducted with a multiple-tube technique to demonstrate applicability and comparability of results.


8 To assess the comparability of results obtained with individual methods, it is suggested that side-by-side tests be conducted across seasons of the year with the water samples routinely tested in accordance with the most current Standard Methods for the Examination of Water and Wastewater or EPA alternate test procedure (ATP) guidelines.


9 Annual Book of ASTM Standards-Water and Environmental Technology, Section 11.02. 2000, 1999, 1996. ASTM International.


10 Official Methods of Analysis of AOAC International. 16th Edition, 4th Revision, 1998. AOAC International.


11 Recommended for enumeration of target organism in sewage sludge.


12 The multiple-tube fermentation test is used in 9221B.2-2014. Lactose broth may be used in lieu of lauryl tryptose broth (LTB), if at least 25 parallel tests are conducted between this broth and LTB using the water samples normally tested, and this comparison demonstrates that the false-positive rate and false-negative rate for total coliform using lactose broth is less than 10 percent. No requirement exists to run the completed phase on 10 percent of all total coliform-positive tubes on a seasonal basis.


13 These tests are collectively known as defined enzyme substrate tests.


14 After prior enrichment in a presumptive medium for total coliform using 9221B.2-2014, all presumptive tubes or bottles showing any amount of gas, growth or acidity within 48 h ± 3 h of incubation shall be submitted to 9221F-2014. Commercially available EC-MUG media or EC media supplemented in the laboratory with 50 µg/mL of MUG may be used.


15 Method 1680: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation Using Lauryl-Tryptose Broth (LTB) and EC Medium, EPA-821-R-14-009. September 2014. U.S. EPA.


16 Samples shall be enumerated by the multiple-tube or multiple-well procedure. Using multiple-tube procedures, employ an appropriate tube and dilution configuration of the sample as needed and report the Most Probable Number (MPN). Samples tested with Colilert® may be enumerated with the multiple-well procedures, Quanti-Tray® or Quanti-Tray®/2000 and the MPN calculated from the table provided by the manufacturer.


17 Colilert-18® is an optimized formulation of the Colilert® for the determination of total coliforms and E. coli that provides results within 18 h of incubation at 35 °C rather than the 24 h required for the Colilert® test and is recommended for marine water samples.


18 Descriptions of the Colilert®, Colilert-18®, Quanti-Tray®, and Quanti-Tray®/2000 may be obtained from IDEXX Laboratories, Inc.


19 A description of the mColiBlue24® test is available from Hach Company.


20 Method 1681: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation Using A-1 Medium, EPA-821-R-06-013. July 2006. U.S. EPA.


21 Method 1603: Escherichia coli (E. coli) in Water by Membrane Filtration Using Modified Membrane-Thermotolerant Escherichia coli Agar (modified mTEC), EPA-821-R-14-010. September 2014. U.S. EPA.


22 Method 1682: Salmonella in Sewage Sludge (Biosolids) by Modified Semisolid Rappaport-Vassiliadis (MSRV) Medium, EPA-821-R-14-012. September 2014. U.S. EPA.


23 A description of the Enterolert® test may be obtained from IDEXX Laboratories Inc.


24 Method 1600: Enterococci in Water by Membrane Filtration Using Membrane-Enterococcus Indoxyl-β-D-Glucoside Agar (mEI), EPA-821-R-14-011. September 2014. U.S. EPA.


25 Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, EPA-821-R-02-012. Fifth Edition, October 2002. U.S. EPA; and U.S. EPA Whole Effluent Toxicity Methods Errata Sheet, EPA 821-R-02-012-ES. December 2016.


26 Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, EPA-821-R-02-013. Fourth Edition, October 2002. U.S. EPA; and U.S. EPA Whole Effluent Toxicity Methods Errata Sheet, EPA 821-R-02-012-ES. December 2016.


27 Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, EPA-821-R-02-014. Third Edition, October 2002. U.S. EPA; and U.S. EPA Whole Effluent Toxicity Methods Errata Sheet, EPA 821-R-02-012-ES. December 2016.


28 To use Colilert-18® to assay for fecal coliforms, the incubation temperature is 44.5 ± 0.2 °C, and a water bath incubator is used.


29 On a monthly basis, at least ten blue colonies from positive samples must be verified using Lauryl Tryptose Broth and EC broth, followed by count adjustment based on these results; and representative non-blue colonies should be verified using Lauryl Tryptose Broth. Where possible, verifications should be done from randomized sample sources.


30 On a monthly basis, at least ten sheen colonies from positive samples must be verified using lauryl tryptose broth and brilliant green lactose bile broth, followed by count adjustment based on these results; and representative non-sheen colonies should be verified using lauryl tryptose broth. Where possible, verifications should be done from randomized sample sources.


31 Subject coliform positive samples determined by 9222 B-2015 or other membrane filter procedure to 9222 I-2015 using NA-MUG media.


32 Verification of colonies by incubation of BHI agar at 10 ± 0.5 °C for 48 ± 3 h is optional. As per the Errata to the 23rd Edition of Standard Methods for the Examination of Water and Wastewater “Growth on a BHI agar plate incubated at 10 ± 0.5 °C for 48 ± 3 h is further verification that the colony belongs to the genus Enterococcus.”


33 9221 F.2-2014 allows for simultaneous detection of E. coli and thermotolerant fecal coliforms by adding inverted vials to EC-MUG; the inverted vials collect gas produced by thermotolerant fecal coliforms.


Table IB—List of Approved Inorganic Test Procedures

Parameter
Methodology
58
EPA
52
Standard methods
84
ASTM
USGS/AOAC/Other
1. Acidity, as CaCO3, mg/LElectrometric endpoint or phenolphthalein endpoint2310 B-2011D1067-16I-1020-85.
2
2. Alkalinity, as CaCO3, mg/LElectrometric or Colorimetric titration to pH 4.5, Manual2320 B-2011D1067-16973.43,
3 I-1030-85.
2
Automatic310.2 (Rev. 1974)
1		I-2030-85.
2
3. Aluminum—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 D-2011 or 3111 E-2011I-3051-85.
2
AA furnace3113 B-2010.
STGFAA200.9, Rev. 2.2 (1994)/
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
Direct Current Plasma (DCP)
36		D4190-15See footnote.
34
Colorimetric (Eriochrome cyanine R)3500-Al B-2011.
4. Ammonia (as N), mg/LManual distillation
6 or gas diffusion (pH > 11), followed by any of the following:		350.1, Rev. 2.0 (1993)4500-NH3 B-2011973.49.
3
NesslerizationD1426-15 (A)973.49,
3 I-3520-85.
2
Titration4500-NH3 C-2011.
Electrode4500-NH3 D-2011 or E-2011D1426-15 (B).
Manual phenate, salicylate, or other substituted phenols in Berthelot reaction-based methods4500-NH3 F-2011See footnote.
60
Automated phenate, salicylate, or other substituted phenols in Berthelot reaction-based methods350.1,
30 Rev. 2.0 (1993)		4500-NH3 G-2011 4500-NH3 H-2011I-4523-85,
2 I-2522-90.
80
Automated electrodeSee footnote.
7
Ion ChromatographyD6919-17.
Automated gas diffusion, followed by conductivity cell analysisTimberline Ammonia-001.
74
Automated gas diffusion followed by fluorescence detector analysisFIAlab100.
82
5. Antimony—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011.
AA furnace3113 B-2010.
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
6. Arsenic-Total,
4 mg/L		Digestion,
4 followed by any of the following:		206.5 (Issued 1978)
1.
AA gaseous hydride3114 B-2011 or 3114 C-2011D2972-15 (B)I-3062-85.
2
AA furnace3113 B-2010D2972-15 (C)I-4063-98.
49
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05.
70
Colorimetric (SDDC)3500-As B-2011D2972-15 (A)I-3060-85.
2
7. Barium-Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 D-2011I-3084-85.
2
AA furnace3113 B-2010D4382-18.
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCP
36		See footnote.
34
8. Beryllium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 D-2011 or 3111 E-2011D3645-15 (A)I-3095-85.
2
AA furnace3113 B-2010D3645-15 (B).
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCPD4190-15See footnote.
34
Colorimetric (aluminon)See footnote.
61.
9. Biochemical oxygen demand (BOD5), mg/LDissolved Oxygen Depletion5210 B-2016
85		973.44,
3 p. 17,
9 I-1578-78,
8 See footnote.
10, 63
10. Boron—Total,
37 mg/L		Colorimetric (curcumin)4500-B B-2011I-3112-85.
2
ICP/AES200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCPD4190-15S7ee footnote.
34
11. Bromide, mg/LElectrodeD1246-16I-1125-85.
2
Ion Chromatography300.0, Rev 2.1 (1993) and 300.1, Rev 1.0 (1997)4110 B-2011, C-2011, D-2011D4327-17993.30,
3 I-2057-85.
79
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
12. Cadmium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011 or 3111 C-2011D3557-17 (A or B)974.27,
3 p. 37,
9 I-3135-85
2 or I-3136-85.
2
AA furnace3113 B-2010D3557-17 (D)I-4138-89.
51
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-1472-85
2 or I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCP
36		D4190-15See footnote.
34
Voltammetry
11		D3557-17 (C).
Colorimetric (Dithizone)3500-Cd-D-1990.
13. Calcium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011D511-14 (B)I-3152-85.
2
ICP/AES200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCPSee footnote.
34
Titrimetric (EDTA)3500-Ca B-2011D511-14 (A).
Ion ChromatographyD6919-17.
14. Carbonaceous biochemical oxygen demand (CBOD5), mg/L
12		Dissolved Oxygen Depletion with nitrification inhibitor5210 B-2016
85		See footnote.35 63
15. Chemical oxygen demand (COD), mg/LTitrimetric410.3 (Rev. 1978)
1		5220 B-2011 or C-2011D1252-06(12) (A)973.46,
3 p. 17,
9 I-3560-85.
2
Spectrophotometric, manual or automatic410.4, Rev. 2.0 (1993)5220 D-2011D1252-06(12) (B)See footnotes.13 14 83, I-3561-85.
2
16. Chloride, mg/LTitrimetric: (silver nitrate)4500-Cl– B-2011D512-12 (B)I-1183-85.
2
(Mercuric nitrate)4500-Cl– C-2011D512-12 (A)973.51,
3 I-1184-85.
2
Colorimetric: manualI-1187-85.
2
Automated (ferricyanide)4500-Cl– E-2011I-2187-85.
2
Potentiometric Titration4500-Cl– D-2011.
Ion Selective ElectrodeD512-12 (C).
Ion Chromatography300.0, Rev 2.1 (1993) and 300.1, Rev 1.0 (1997)4110 B-2011 or 4110 C-2011D4327-17993.30,
3 I-2057-90.
51
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
17. Chlorine-Total residual, mg/LAmperometric direct4500-Cl D-2011D1253-14.
Amperometric direct (low level)4500-Cl E-2011.
Iodometric direct4500-Cl B-2011.
Back titration ether end-point
15		4500-Cl C-2011.
DPD-FAS4500-Cl F-2011.
Spectrophotometric, DPD4500-Cl G-2011.
ElectrodeSee footnote.
16
17A. Chlorine-Free Available, mg/LAmperometric direct4500-Cl D-2011D1253-14.
Amperometric direct (low level)4500-Cl E-2011.
DPD-FAS4500-Cl F-2011.
Spectrophotometric, DPD4500-Cl G-2011.
18. Chromium VI dissolved, mg/L0.45-micron filtration followed by any of the following:
AA chelation-extraction3111 C-2011I-1232-85.
2
Ion Chromatography218.6, Rev. 3.3 (1994)3500-Cr C-2011D5257-17993.23.
3
Colorimetric (diphenyl-carbazide)3500-Cr B-2011D1687-17 (A)I-1230-85.
2
19. Chromium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011D1687-17 (B)974.27,
3 I-3236-85.
2
AA chelation-extraction3111 C-2011.
AA furnace3113 B-2010D1687-17 (C)I-3233-93.
46
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev 4.2 (2003),
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05
70 I-4472-97.
81
DCP
36		D4190-15See footnote.
34
Colorimetric (diphenyl-carbazide)3500-Cr B-2011.
20. Cobalt—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011 or 3111 C-2011D3558-15 (A or B)p. 37,
9 I-3239-85.
2
AA furnace3113 B-2010D3558-15 (C)I-4243-89.
51
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES200.7, Rev. 4.4 (1994)3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05
70 I-4472-97.
81
DCPD4190-15See footnote.
34
21. Color, platinum cobalt units or dominant wavelength, hue, luminance purityColorimetric (ADMI)2120 F-2011
78.
Platinum cobalt visual comparison2120 B-2011I-1250-85.
2
SpectrophotometricSee footnote
18
22. Copper—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011 or 3111 C-2011D1688-17 (A or B)974.27,
3 p. 37,
9 I-3270-85
2 or I-3271-85.
2
AA furnace3113 B-2010D1688-17 (C)I-4274-89.
51
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05,
70, I-4472-97.
81
DCP
36		D4190-15See footnote.
34
Colorimetric (Neocuproine)3500-Cu B-2011.
Colorimetric (Bathocuproine)3500-Cu C-2011See footnote.
19
23. Cyanide—Total, mg/LAutomated UV digestion/distillation and ColorimetryKelada-01.
55
Segmented Flow Injection, In-Line Ultraviolet Digestion, followed by gas diffusion amperometryD7511-12(17).
Manual distillation with MgCl2, followed by any of the following:335.4, Rev. 1.0 (1993)
57		4500-CN– B-2016 and C-2016D2036-09(15)(A), D7284-13(17)10-204-00-1-X.
56
Flow Injection, gas diffusion amperometryD2036-09(15)(A) D7284-13(17).
Titrimetric4500-CN– D-2016D2036-09(15)(A)p. 22.
9
Spectrophotometric, manual4500-CN– E-2016D2036-09(15)(A)I-3300-85.
2
Semi-Automated
20		335.4, Rev. 1.0 (1993)
57		4500-CN– N-201610-204-00-1-X,
56 I-4302-85.
2
Ion ChromatographyD2036-09(15)(A).
Ion Selective Electrode4500-CN– F-2016D2036-09(15)(A).
24. Cyanide-Available, mg/LCyanide Amenable to Chlorination (CATC); Manual distillation with MgCl2, followed by Titrimetric or Spectrophotometric4500-CN– G-2016D2036-09(15)(B).
Flow injection and ligand exchange, followed by gas diffusion amperometry
59		D6888-16OIA-1677-09.
44
Automated Distillation and Colorimetry (no UV digestion)Kelada-01.
55
24.A Cyanide-Free, mg/LFlow Injection, followed by gas diffusion amperometryD7237-15 (A)OIA-1677-09.
44
Manual micro-diffusion and colorimetryD4282-15.
25. Fluoride—Total, mg/LManual distillation,
6 followed by any of the following:		4500-F– B-2011D1179-16 (A).
Electrode, manual4500-F– C-2011D1179-16 (B).
Electrode, automatedI-4327-85.
2
Colorimetric, (SPADNS)4500-F– D-2011.
Automated complexone4500-F– E-2011.
Ion Chromatography300.0, Rev 2.1 (1993) and 300.1, Rev 1.0 (1997)4110 B-2011 or C-2011D4327-17993.30.
3
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
26. Gold—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011.
AA furnace231.2 (Issued 1978)
1		3113 B-2010.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCPSee footnote.
34
27. Hardness—Total, as CaCO3, mg/LAutomated colorimetric130.1 (Issued 1971)
1.
Titrimetric (EDTA)2340 C-2011D1126-17973.52B
3, I-1338-85.
2
Ca plus Mg as their carbonates, by any approved method for Ca and Mg (See Parameters 13 and 33), provided that the sum of the lowest point of quantitation for Ca and Mg is below the NPDES permit requirement for Hardness2340 B-2011.
28. Hydrogen ion (pH), pH unitsElectrometric measurement4500-H
+ B-2011		D1293-99 (A or B)973.41,
3 I-1586-85.
2
Automated electrode150.2 (Dec. 1982)
1		See footnote,
21 I-2587-85.
2
29. Iridium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011.
AA furnace235.2 (Issued 1978)
1.
ICP/MS3125 B-2011.
30. Iron—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011 or 3111 C-2011D1068-15 (A)974.27,
3 I-3381-85.
2
AA furnace3113 B-2010D1068-15 (B).
STGFAA200.9, Rev. 2.2 (1994)
ICP/AES
36		200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCP
36		D4190-15See footnote.
34
Colorimetric (Phenanthroline)3500-Fe B-2011D1068-15 (C)See footnote.
22
31. Kjeldahl Nitrogen
5—Total, (as N), mg/L		Manual digestion
20 and distillation or gas diffusion, followed by any of the following:		4500-Norg B-2011 or C-2011 and 4500-NH3 B-2011D3590-17 (A)I-4515-91.
45
Titration4500-NH3 C-2011973.48.
3
NesslerizationD1426-15 (A).
Electrode4500-NH3 D-2011 or E-2011D1426-15 (B).
Semi-automated phenate350.1, Rev. 2.0 (1993)4500-NH3 G-2011 4500-NH3 H-2011
Manual phenate, salicylate, or other substituted phenols in Berthelot reaction based methods4500-NH3 F-2011See footnote.
60
Automated gas diffusion, followed by conductivity cell analysisTimberline Ammonia-001.
74
Automated gas diffusion followed by fluorescence detector analysisFIAlab 100.
82
Automated Methods for TKN that do not require manual distillation
Automated phenate, salicylate, or other substituted phenols in Berthelot reaction based methods colorimetric (auto digestion and distillation)351.1 (Rev. 1978)
1		I-4551-78.
8
Semi-automated block digestor colorimetric (distillation not required)351.2, Rev. 2.0 (1993)4500-Norg D-2011D3590-17 (B)I-4515-91
45
Block digester, followed by Auto distillation and TitrationSee footnote.
39
Block digester, followed by Auto distillation and NesslerizationSee footnote.
40
Block Digester, followed by Flow injection gas diffusion (distillation not required)See footnote.
41
Digestion with peroxdisulfate, followed by Spectrophotometric (2,6-dimethyl phenol)Hach 10242.
76
Digestion with persulfate, followed by ColorimetricNCASI TNTP W10900.
77
32. Lead—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011 or 3111 C-2011D3559-15 (A or B)974.27,
3 I-3399-85.
2
AA furnace3113 B-2010D3559-15 (D)I-4403-89.
51
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCP
36		D4190-15See footnote.
34
Voltammetry
11		D3559-15 (C).
Colorimetric (Dithizone)3500-Pb B-2011.
33. Magnesium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011D511-14 (B)974.27,
3 I-3447-85.
2
ICP/AES200.5, Rev. 4.2 (2003)
68; 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCPSee footnote.
34
Ion ChromatographyD6919-17.
34. Manganese—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011D858-17 (A or B)974.27,
3 I-3454-85.
2
AA furnace3113 B-2010D858-17 (C).
STGFAA200.9, Rev. 2.2 (1994)
ICP/AES
36		200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCP
36		D4190-15See footnote.
34
Colorimetric (Persulfate)3500-Mn B-2011920.203.
3
Colorimetric (Periodate)See footnote.
23
35. Mercury—Total, mg/LCold vapor, Manual245.1, Rev. 3.0 (1994)3112 B-2011D3223-17977.22,
3 I-3462-85.
2
Cold vapor, Automated245.2 (Issued 1974)
1.
Cold vapor atomic fluorescence spectrometry (CVAFS)245.7 Rev. 2.0 (2005)
17		I-4464-01.
71
Purge and Trap CVAFS1631E
43.
36. Molybdenum—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 D-2011I-3490-85.
2
AA furnace3113 -2010I-3492-96.
47
ICP/AES200.7, Rev. 4.4 (1994)3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCPSee footnote.
34
37. Nickel—Total,
4

mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011 or 3111 C-2011D1886-14 (A or B)I-3499-85
2
AA furnace3113 B-2010D1886-14 (C)I-4503-89.
51
STGFAA200.9, Rev. 2.2 (1994)
ICP/AES
36		200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05
70 I-4472-97.
81
DCP
36		D4190-15See footnote.
34
38. Nitrate (as N), mg/LIon Chromatography300.0, Rev. 2.1 (1993) and 300.1, Rev. 1.0 (1997)4110 B-2011 or C-2011D4327-17993.30.
3
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
Ion Selective Electrode4500-NO3– D-2016.
Colorimetric (Brucine sulfate)352.1 (Issued 1971)
1		973.50,
3 419D
1
7, p. 28.
9
Spectrophotometric (2,6-dimethylphenol)Hach 10206
75
Nitrate-nitrite N minus Nitrite N (See parameters 39 and 40)
39. Nitrate-nitrite (as N), mg/LCadmium reduction, Manual4500-NO3– E-2016D3867-16 (B).
Cadmium reduction, Automated353.2, Rev. 2.0 (1993)4500-NO3– F-2016 4500-NO3– I-2016D3867-16 (A)I-2545-90.
51
Automated hydrazine4500-NO3– H-2016.
Reduction/ColorimetricSee footnote.
62
Ion Chromatography300.0, Rev. 2.1 (1993) and 300.1, Rev. 1.0 (1997)4110 B-2011 or C-2011D4327-17993.30.
3
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
Enzymatic reduction, followed by automated colorimetric determinationD7781-14I-2547-11.
72

I-2548-11.
72

N07-0003.
73
Enzymatic reduction, followed by manual colorimetric determination4500-NO3– J-2018.
Spectrophotometric (2,6-dimethylphenol)Hach 10206.
75
40. Nitrite (as N), mg/LSpectrophotometric: Manual4500-NO2– B-2011See footnote.
25
Automated (Diazotization)I-4540-85,
2 See footnote.
62 I-2540-90.
80
Automated (*bypass cadmium reduction)353.2, Rev. 2.0 (1993)4500-NO3– F-2016 4500-NO3– I-2016D3867-16 (A)I-4545-85.
2
Manual (*bypass cadmium or enzymatic reduction)4500-NO3– E-2016, 4500-NO3– J-2018D3867-16 (B).
Ion Chromatography300.0, Rev. 2.1 (1993) and 300.1, Rev. 1.0 (1997)4110 B-2011 or C-2011D4327-17993.30.
3
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
Automated (*bypass Enzymatic reduction)D7781-14I-2547-11
72 I-2548-11
72 N07-0003.
73
41. Oil and grease—Total recoverable, mg/LHexane extractable material (HEM): n-Hexane extraction and gravimetry1664 Rev. A; 1664 Rev. B
42		5520 B-2011
38.
Silica gel treated HEM (SGT-HEM): Silica gel treatment and gravimetry1664 Rev. A; 1664 Rev. B
42		5520 B-2011
38 and 5520 F-2011
38.
42. Organic carbon—Total (TOC), mg/LCombustion5310 B-2014D7573-09(17)973.47,
3 p. 14.
24
Heated persulfate or UV persulfate oxidation5310 C-2014 5310 D-2011D4839-03(17)973.47,
3, p. 14.
24
43. Organic nitrogen (as N), mg/LTotal Kjeldahl N (Parameter 31) minus ammonia N (Parameter 4)
44. Ortho-phosphate (as P), mg/LAscorbic acid method:
Automated365.1, Rev. 2.0 (1993)4500-P F-2011 or G-2011973.56,
3 I-4601-85,
2 I-2601-90.
80
Manual, single-reagent4500-P E-2011D515-88 (A)973.55.
3
Manual, two-reagent365.3 (Issued 1978)
1.
Ion Chromatography300.0, Rev. 2.1 (1993) and 300.1, Rev. 1.0 (1997)4110 B-2011 or C-2011D4327-17993.30.
3
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
45. Osmium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 D-2011.
AA furnace252.2 (Issued 1978)
1.
46. Oxygen, dissolved, mg/LWinkler (Azide modification)4500-O (B-F)-2016D888-12 (A)973.45B,
3 I-1575-78.
8
Electrode4500-O G-2016D888-12 (B)I-1576-78.
8
Luminescence-Based Sensor4500-O H-2016D888-12 (C)See footnote.
63 See footnote.
64
47. Palladium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011.
AA furnace253.2 (Issued 1978)
1.
ICP/MS3125 B-2011.
DCPSee footnote.
34
48. Phenols, mg/LManual distillation,
26 followed by any of the following:		420.1 (Rev. 1978)
1		5530 B-2010D1783-01(12).
Colorimetric (4AAP) manual420.1 (Rev. 1978)
1		5530 D-2010
27		D1783-01(12) (A or B).
Automated colorimetric (4AAP)420.4 Rev. 1.0 (1993)
49. Phosphorus (elemental), mg/LGas-liquid chromatographySee footnote.
28
50. Phosphorus—Total, mg/LDigestion,
20 followed by any of the following:		4500-P B (5)-2011973.55.
3
Manual365.3 (Issued 1978)
1		4500-P E-2011D515-88 (A).
Automated ascorbic acid reduction365.1 Rev. 2.0 (1993)4500-P (F-H)-2011973.56,
3 I-4600-85.
2
ICP/AES 4 36200.7, Rev. 4.4 (1994)3120 B-2011I-4471-97.
50
Semi-automated block digestor (TKP digestion)365.4 (Issued 1974)
1		D515-88 (B)I-4610-91.
48
Digestion with persulfate, followed by ColorimetricNCASI TNTP W10900.
77
51. Platinum—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011.
AA furnace255.2 (Issued 1978)
1.
ICP/MS3125 B-2011.
DCPSee footnote.
34
52. Potassium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011973.53,
3 I-3630-85.
2
ICP/AES200.7, Rev. 4.4 (1994)3120 B-2011.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
Flame photometric3500-K B-2011.
Electrode3500-K C-2011.
Ion ChromatographyD6919-17.
53. Residue—Total, mg/LGravimetric, 103-105°2540 B-2015I-3750-85.
2
54. Residue—filterable, mg/LGravimetric, 180°2540 C-2015D5907-13I-1750-85.
2
55. Residue—non-filterable (TSS), mg/LGravimetric, 103-105° post-washing of residue2540 D-2015D5907-13I-3765-85.
2
56. Residue—settleable, ml/LVolumetric (Imhoff cone), or gravimetric2540 F-2015.
57. Residue—Volatile, mg/LGravimetric, 550°160.4 (Issued 1971)
1		2540 E-2015I-3753-85.
2
58. Rhodium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration, or3111 B-2011.
AA furnace265.2 (Issued 1978)
1.
ICP/MS3125 B-2011.
59. Ruthenium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration, or3111 B-2011.
AA furnace267.2
1.
ICP/MS3125 B-2011.
60. Selenium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA furnace3113 B-2010D3859-15 (B)I-4668-98.
49
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES
36		200.5, Rev 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05
70 I-4472-97.
81
AA gaseous hydride3114 B-2011, or 3114 C-2011D3859-15 (A)I-3667-85.
2
61. Silica—Dissolved,
37 mg/L		0.45-micron filtration followed by any of the following:
Colorimetric, Manual4500-SiO2 C-2011D859-16I-1700-85.
2
Automated (Molybdosilicate)4500-SiO2 E-2011 or F-2011I-2700-85.
2
ICP/AES200.5, Rev. 4.2 (2003)
68; 200.7, Rev. 4.4 (1994)		3120 B-2011I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
62. Silver—Total,4 31 mg/LDigestion,4 29 followed by any of the following:
AA direct aspiration3111 B-2011 or 3111 C-2011974.27,
3 p. 37,
9 I-3720-85.
2
AA furnace3113 B-2010I-4724-89.
51
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4472-97.
81
DCPSee footnote.
34
63. Sodium—Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011973.54,
3 I-3735-85.
2
ICP/AES200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCPSee footnote.
34
Flame photometric3500-Na B-2011.
Ion ChromatographyD6919-17.
64. Specific conductance, micromhos/cm at 25 °CWheatstone bridge120.1 (Rev. 1982)
1		2510 B-2011D1125-95(99) (A)973.40,
3 I-2781-85.
2
65. Sulfate (as SO4), mg/LAutomated colorimetric375.2, Rev. 2.0 (1993)4500-SO42- F-2011 or G-2011
Gravimetric4500-SO42- C-2011 or D-2011925.54.
3
Turbidimetric4500-SO42- E-2011D516-16.
Ion Chromatography300.0, Rev. 2.1 (1993) and 300.1, Rev. 1.0 (1997)4110 B-2011 or C-2011D4327-17993.303, I-4020-05
70
CIE/UV4140 B-2011D6508-15D6508, Rev. 2.
54
66. Sulfide (as S), mg/LSample Pretreatment4500-S2- B, C-2011.
Titrimetric (iodine)4500-S2- F-2011I-3840-85.
2
Colorimetric (methylene blue)4500-S2- D-2011.
Ion Selective Electrode4500-S2- G-2011D4658-15.
67. Sulfite (as SO3), mg/LTitrimetric (iodine-iodate)4500-SO32- B-2011.
68. Surfactants, mg/LColorimetric (methylene blue)5540 C-2011D2330-02.
69. Temperature, °CThermometric2550 B-2010See footnote.
32
70. Thallium-Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011.
AA furnace279.2 (Issued 1978)
1		3113 B-2010.
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES200.7, Rev. 4.4 (1994)3120 B-2011D1976-12.
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4471-97
50 I-4472-97.
81
71. Tin-Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 B-2011I-3850-78.
8
AA furnace3113 B-2010.
STGFAA200.9, Rev. 2.2 (1994).
ICP/AES200.5, Rev. 4.2 (2003)
68; 200.7, Rev. 4.4 (1994).
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
72. Titanium-Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 D-2011.
AA furnace283.2 (Issued 1978)
1.
ICP/AES200.7, Rev. 4.4 (1994).
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14.
3
DCPSee footnote.
34
73. Turbidity, NTU
53		Nephelometric180.1, Rev. 2.0 (1993)2130 B-2011D1889-00I-3860-85
2

See footnote.
65

See footnote.
66

See footnote.
67
74. Vanadium-Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration3111 D-2011.
AA furnace3113 B-2010D3373-17.
ICP/AES200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05.
70
DCPD4190-15See footnote.
34
Colorimetric (Gallic Acid)3500-V B-2011.
75. Zinc-Total,
4 mg/L		Digestion,
4 followed by any of the following:
AA direct aspiration
36		3111 B-2011 or 3111 C-2011D1691-17 (A or B)974.27,
3 p. 37,
9 I-3900-85.
2
AA furnace289.2 (Issued 1978)
1.
ICP/AES
36		200.5, Rev. 4.2 (2003);
68 200.7, Rev. 4.4 (1994)		3120 B-2011D1976-12I-4471-97.
50
ICP/MS200.8, Rev. 5.4 (1994)3125 B-2011D5673-16993.14,
3 I-4020-05
70 I-4472-97.
81
DCP
36		D4190-15See footnote.
34
Colorimetric (Zincon)3500 Zn B-2011See footnote.
33
76. Acid Mine Drainage1627
69.

Table IB Notes:


1 Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020. Revised March 1983 and 1979, where applicable. U.S. EPA.


2 Methods for Analysis of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resource Investigations of the U.S. Geological Survey, Book 5, Chapter A1., unless otherwise stated. 1989. USGS.


3 Official Methods of Analysis of the Association of Official Analytical Chemists, Methods Manual, Sixteenth Edition, 4th Revision, 1998. AOAC International.


4 For the determination of total metals (which are equivalent to total recoverable metals) the sample is not filtered before processing. A digestion procedure is required to solubilize analytes in suspended material and to break down organic-metal complexes (to convert the analyte to a detectable form for colorimetric analysis). For non-platform graphite furnace atomic absorption determinations, a digestion using nitric acid (as specified in Section 4.1.3 of Methods for Chemical Analysis of Water and Wastes) is required prior to analysis. The procedure used should subject the sample to gentle acid refluxing, and at no time should the sample be taken to dryness. For direct aspiration flame atomic absorption (FLAA) determinations, a combination acid (nitric and hydrochloric acids) digestion is preferred, prior to analysis. The approved total recoverable digestion is described as Method 200.2 in Supplement I of “Methods for the Determination of Metals in Environmental Samples” EPA/600R-94/111, May, 1994, and is reproduced in EPA Methods 200.7, 200.8, and 200.9 from the same Supplement. However, when using the gaseous hydride technique or for the determination of certain elements such as antimony, arsenic, selenium, silver, and tin by non-EPA graphite furnace atomic absorption methods, mercury by cold vapor atomic absorption, the noble metals and titanium by FLAA, a specific or modified sample digestion procedure may be required, and, in all cases the referenced method write-up should be consulted for specific instruction and/or cautions. For analyses using inductively coupled plasma-atomic emission spectrometry (ICP-AES), the direct current plasma (DCP) technique or EPA spectrochemical techniques (platform furnace AA, ICP-AES, and ICP-MS), use EPA Method 200.2 or an approved alternate procedure (e.g., CEM microwave digestion, which may be used with certain analytes as indicated in Table IB); the total recoverable digestion procedures in EPA Methods 200.7, 200.8, and 200.9 may be used for those respective methods. Regardless of the digestion procedure, the results of the analysis after digestion procedure are reported as “total” metals.


5 Copper sulfate or other catalysts that have been found suitable may be used in place of mercuric sulfate.


6 Manual distillation is not required if comparability data on representative effluent samples are on file to show that this preliminary distillation step is not necessary; however, manual distillation will be required to resolve any controversies. In general, the analytical method should be consulted regarding the need for distillation. If the method is not clear, the laboratory may compare a minimum of 9 different sample matrices to evaluate the need for distillation. For each matrix, a matrix spike and matrix spike duplicate are analyzed both with and without the distillation step (for a total of 36 samples, assuming 9 matrices). If results are comparable, the laboratory may dispense with the distillation step for future analysis. Comparable is defined as


7 Industrial Method Number 379-75 WE Ammonia, Automated Electrode Method, Technicon Auto Analyzer II. February 19, 1976. Bran & Luebbe Analyzing Technologies Inc.


8 The approved method is that cited in Methods for Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A1. 1979. USGS.


9 American National Standard on Photographic Processing Effluents. April 2, 1975. American National Standards Institute.


10 In-Situ Method 1003-8-2009, Biochemical Oxygen Demand (BOD) Measurement by Optical Probe. 2009. In-Situ Incorporated.


11 The use of normal and differential pulse voltage ramps to increase sensitivity and resolution is acceptable.


12 Carbonaceous biochemical oxygen demand (CBOD5) must not be confused with the traditional BOD5 test method which measures “total 5-day BOD.” The addition of the nitrification inhibitor is not a procedural option but must be included to report the CBOD5 parameter. A discharger whose permit requires reporting the traditional BOD5 may not use a nitrification inhibitor in the procedure for reporting the results. Only when a discharger’s permit specifically states CBOD5 is required can the permittee report data using a nitrification inhibitor.


13 OIC Chemical Oxygen Demand Method. 1978. Oceanography International Corporation.


14 Method 8000, Chemical Oxygen Demand, Hach Handbook of Water Analysis, 1979. Hach Company.


15 The back-titration method will be used to resolve controversy.


16 Orion Research Instruction Manual, Residual Chlorine Electrode Model 97-70. 1977. Orion Research Incorporated. The calibration graph for the Orion residual chlorine method must be derived using a reagent blank and three standard solutions, containing 0.2, 1.0, and 5.0 mL 0.00281 N potassium iodate/100 mL solution, respectively.


17 Method 245.7, Mercury in Water by Cold Vapor Atomic Fluorescence Spectrometry, EPA-821-R-05-001. Revision 2.0, February 2005. US EPA.


18 National Council of the Paper Industry for Air and Stream Improvement (NCASI) Technical Bulletin 253 (1971) and Technical Bulletin 803, May 2000.


19 Method 8506, Bicinchoninate Method for Copper, Hach Handbook of Water Analysis. 1979. Hach Company.


20 When using a method with block digestion, this treatment is not required.


21 Industrial Method Number 378-75WA, Hydrogen ion (pH) Automated Electrode Method, Bran & Luebbe (Technicon) Autoanalyzer II. October 1976. Bran & Luebbe Analyzing Technologies.


22 Method 8008, 1,10-Phenanthroline Method using FerroVer Iron Reagent for Water. 1980. Hach Company.


23 Method 8034, Periodate Oxidation Method for Manganese, Hach Handbook of Wastewater Analysis. 1979. Hach Company.


24 Methods for Analysis of Organic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A3, (1972 Revised 1987). 1987. USGS.


25 Method 8507, Nitrogen, Nitrite-Low Range, Diazotization Method for Water and Wastewater. 1979. Hach Company.


26 Just prior to distillation, adjust the sulfuric-acid-preserved sample to pH 4 with 1 + 9 NaOH.


27 The colorimetric reaction must be conducted at a pH of 10.0 ± 0.2.


28 Addison, R.F., and R.G. Ackman. 1970. Direct Determination of Elemental Phosphorus by Gas-Liquid Chromatography, Journal of Chromatography, 47(3):421-426.


29 Approved methods for the analysis of silver in industrial wastewaters at concentrations of 1 mg/L and above are inadequate where silver exists as an inorganic halide. Silver halides such as the bromide and chloride are relatively insoluble in reagents such as nitric acid but are readily soluble in an aqueous buffer of sodium thiosulfate and sodium hydroxide to pH of 12. Therefore, for levels of silver above 1 mg/L, 20 mL of sample should be diluted to 100 mL by adding 40 mL each of 2 M Na2S2O3 and NaOH. Standards should be prepared in the same manner. For levels of silver below 1 mg/L the approved method is satisfactory.


30 The use of EDTA decreases method sensitivity. Analysts may omit EDTA or replace with another suitable complexing reagent provided that all method-specified quality control acceptance criteria are met.


31 For samples known or suspected to contain high levels of silver (e.g., in excess of 4 mg/L), cyanogen iodide should be used to keep the silver in solution for analysis. Prepare a cyanogen iodide solution by adding 4.0 mL of concentrated NH4OH, 6.5 g of KCN, and 5.0 mL of a 1.0 N solution of I2 to 50 mL of reagent water in a volumetric flask and dilute to 100.0 mL. After digestion of the sample, adjust the pH of the digestate to >7 to prevent the formation of HCN under acidic conditions. Add 1 mL of the cyanogen iodide solution to the sample digestate and adjust the volume to 100 mL with reagent water (NOT acid). If cyanogen iodide is added to sample digestates, then silver standards must be prepared that contain cyanogen iodide as well. Prepare working standards by diluting a small volume of a silver stock solution with water and adjusting the pH>7 with NH4OH. Add 1 mL of the cyanogen iodide solution and let stand 1 hour. Transfer to a 100-mL volumetric flask and dilute to volume with water.


32 “Water Temperature-Influential Factors, Field Measurement and Data Presentation,” Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 1, Chapter D1. 1975. USGS.


33 Method 8009, Zincon Method for Zinc, Hach Handbook of Water Analysis, 1979. Hach Company.


34 Method AES0029, Direct Current Plasma (DCP) Optical Emission Spectrometric Method for Trace Elemental Analysis of Water and Wastes. 1986-Revised 1991. Thermo Jarrell Ash Corporation.


35 In-Situ Method 1004-8-2009, Carbonaceous Biochemical Oxygen Demand (CBOD) Measurement by Optical Probe. 2009. In-Situ Incorporated.


36 Microwave-assisted digestion may be employed for this metal, when analyzed by this methodology. Closed Vessel Microwave Digestion of Wastewater Samples for Determination of Metals. April 16, 1992. CEM Corporation


37 When determining boron and silica, only plastic, PTFE, or quartz laboratory ware may be used from start until completion of analysis.


38 Only use n-hexane (n-Hexane—85% minimum purity, 99.0% min. saturated C6 isomers, residue less than 1 mg/L) extraction solvent when determining Oil and Grease parameters—Hexane Extractable Material (HEM), or Silica Gel Treated HEM (analogous to EPA Methods 1664 Rev. A and 1664 Rev. B). Use of other extraction solvents is prohibited.


39 Method PAI-DK01, Nitrogen, Total Kjeldahl, Block Digestion, Steam Distillation, Titrimetric Detection. Revised December 22, 1994. OI Analytical.


40 Method PAI-DK02, Nitrogen, Total Kjeldahl, Block Digestion, Steam Distillation, Colorimetric Detection. Revised December 22, 1994. OI Analytical.


41 Method PAI-DK03, Nitrogen, Total Kjeldahl, Block Digestion, Automated FIA Gas Diffusion. Revised December 22, 1994. OI Analytical.


42 Method 1664 Rev. B is the revised version of EPA Method 1664 Rev. A. U.S. EPA. February 1999, Revision A. Method 1664, n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry. EPA-821-R-98-002. U.S. EPA. February 2010, Revision B. Method 1664, n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry. EPA-821-R-10-001.


43 Method 1631, Revision E, Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry, EPA-821-R-02-019. Revision E. August 2002, U.S. EPA. The application of clean techniques described in EPA’s Method 1669: Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria Levels, EPA-821-R-96-011, are recommended to preclude contamination at low-level, trace metal determinations.


44 Method OIA-1677-09, Available Cyanide by Ligand Exchange and Flow Injection Analysis (FIA). 2010. OI Analytical.


45 Open File Report 00-170, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Ammonium Plus Organic Nitrogen by a Kjeldahl Digestion Method and an Automated Photometric Finish that Includes Digest Cleanup by Gas Diffusion. 2000. USGS.


46 Open File Report 93-449, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Chromium in Water by Graphite Furnace Atomic Absorption Spectrophotometry. 1993. USGS.


47 Open File Report 97-198, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Molybdenum by Graphite Furnace Atomic Absorption Spectrophotometry. 1997. USGS.


48 Open File Report 92-146, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Total Phosphorus by Kjeldahl Digestion Method and an Automated Colorimetric Finish That Includes Dialysis. 1992. USGS.


49 Open File Report 98-639, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Arsenic and Selenium in Water and Sediment by Graphite Furnace-Atomic Absorption Spectrometry. 1999. USGS.


50 Open File Report 98-165, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Elements in Whole-water Digests Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry. 1998. USGS.


51 Open File Report 93-125, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments. 1993. USGS.


52 Unless otherwise indicated, all EPA methods, excluding EPA Method 300.1, are published in U.S. EPA. May 1994. Methods for the Determination of Metals in Environmental Samples, Supplement I, EPA/600/R-94/111; or U.S. EPA. August 1993. Methods for the Determination of Inorganic Substances in Environmental Samples, EPA/600/R-93/100. EPA Method 300.1 is U.S. EPA. Revision 1.0, 1997, including errata cover sheet April 27, 1999. Determination of Inorganic Ions in Drinking Water by Ion Chromatography.


53 Styrene divinyl benzene beads (e.g., AMCO-AEPA-1 or equivalent) and stabilized formazin (e.g., Hach StablCal
TM or equivalent) are acceptable substitutes for formazin.


54 Method D6508-15, Test Method for Determination of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate Electrolyte. 2015. ASTM


55 Kelada-01, Kelada Automated Test Methods for Total Cyanide, Acid Dissociable Cyanide, and Thiocyanate, EPA 821-B-01-009, Revision 1.2, August 2001. U.S. EPA. Note: A 450-W UV lamp may be used in this method instead of the 550-W lamp specified if it provides performance within the quality control (QC) acceptance criteria of the method in a given instrument. Similarly, modified flow cell configurations and flow conditions may be used in the method, provided that the QC acceptance criteria are met.


56 QuikChem Method 10-204-00-1-X, Digestion and Distillation of Total Cyanide in Drinking and Wastewaters using MICRO DIST and Determination of Cyanide by Flow Injection Analysis. Revision 2.2, March 2005. Lachat Instruments.


57 When using sulfide removal test procedures described in EPA Method 335.4-1, reconstitute particulate that is filtered with the sample prior to distillation.


58 Unless otherwise stated, if the language of this table specifies a sample digestion and/or distillation “followed by” analysis with a method, approved digestion and/or distillation are required prior to analysis.


59 Samples analyzed for available cyanide using OI Analytical method OIA-1677-09 or ASTM method D6888-16 that contain particulate matter may be filtered only after the ligand exchange reagents have been added to the samples, because the ligand exchange process converts complexes containing available cyanide to free cyanide, which is not removed by filtration. Analysts are further cautioned to limit the time between the addition of the ligand exchange reagents and sample filtration to no more than 30 minutes to preclude settling of materials in samples.


60 Analysts should be aware that pH optima and chromophore absorption maxima might differ when phenol is replaced by a substituted phenol as the color reagent in Berthelot Reaction (“phenol-hypochlorite reaction”) colorimetric ammonium determination methods. For example, when phenol is used as the color reagent, pH optimum and wavelength of maximum absorbance are about 11.5 and 635 nm, respectively—see, Patton, C.J. and S.R. Crouch. March 1977. Anal. Chem. 49:464-469. These reaction parameters increase to pH > 12.6 and 665 nm when salicylate is used as the color reagent—see, Krom, M.D. April 1980. The Analyst 105:305-316.


61 If atomic absorption or ICP instrumentation is not available, the aluminon colorimetric method detailed in the 19th Edition of Standard Methods for the Examination of Water and Wastewater may be used. This method has poorer precision and bias than the methods of choice.


62 Easy (1-Reagent) Nitrate Method, Revision November 12, 2011. Craig Chinchilla.


63 Hach Method 10360, Luminescence Measurement of Dissolved Oxygen in Water and Wastewater and for Use in the Determination of BOD5 and CBOD5. Revision 1.2, October 2011. Hach Company. This method may be used to measure dissolved oxygen when performing the methods approved in Table IB for measurement of biochemical oxygen demand (BOD) and carbonaceous biochemical oxygen demand (CBOD).


64 In-Situ Method 1002-8-2009, Dissolved Oxygen (DO) Measurement by Optical Probe. 2009. In-Situ Incorporated.


65 Mitchell Method M5331, Determination of Turbidity by Nephelometry. Revision 1.0, July 31, 2008. Leck Mitchell.


66 Mitchell Method M5271, Determination of Turbidity by Nephelometry. Revision 1.0, July 31, 2008. Leck Mitchell.


67 Orion Method AQ4500, Determination of Turbidity by Nephelometry. Revision 5, March 12, 2009. Thermo Scientific.


68 EPA Method 200.5, Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry, EPA/600/R-06/115. Revision 4.2, October 2003. U.S. EPA.


69 Method 1627, Kinetic Test Method for the Prediction of Mine Drainage Quality, EPA-821-R-09-002. December 2011. U.S. EPA.


70 Techniques and Methods Book 5-B1, Determination of Elements in Natural-Water, Biota, Sediment and Soil Samples Using Collision/Reaction Cell Inductively Coupled Plasma-Mass Spectrometry, Chapter 1, Section B, Methods of the National Water Quality Laboratory, Book 5, Laboratory Analysis, 2006. USGS.


71 Water-Resources Investigations Report 01-4132, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Organic Plus Inorganic Mercury in Filtered and Unfiltered Natural Water with Cold Vapor-Atomic Fluorescence Spectrometry, 2001. USGS.


72 USGS Techniques and Methods 5-B8, Chapter 8, Section B, Methods of the National Water Quality Laboratory Book 5, Laboratory Analysis, 2011 USGS.


73 NECi Method N07-0003, “Nitrate Reductase Nitrate-Nitrogen Analysis,” Revision 9.0, March 2014, The Nitrate Elimination Co., Inc.


74 Timberline Instruments, LLC Method Ammonia-001, “Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Conductivity Cell Analysis,” June 2011, Timberline Instruments, LLC.


75 Hach Company Method 10206, “Spectrophotometric Measurement of Nitrate in Water and Wastewater,” Revision 2.1, January 2013, Hach Company.


76 Hach Company Method 10242, “Simplified Spectrophotometric Measurement of Total Kjeldahl Nitrogen in Water and Wastewater,” Revision 1.1, January 2013, Hach Company.


77 National Council for Air and Stream Improvement (NCASI) Method TNTP-W10900, “Total (Kjeldahl) Nitrogen and Total Phosphorus in Pulp and Paper Biologically Treated Effluent by Alkaline Persulfate Digestion,” June 2011, National Council for Air and Stream Improvement, Inc.


78 The pH adjusted sample is to be adjusted to 7.6 for NPDES reporting purposes.


79 I-2057-85 U.S. Geological Survey Techniques of Water-Resources Investigations, Book 5, Chap. A11989, Methods for Determination of Inorganic Substances in Water and Fluvial Sediments, 1989.


80 Methods I-2522-90, I-2540-90, and I-2601-90 U.S. Geological Survey Open-File Report 93-125, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments, 1993.


81 Method I-1472-97, U.S. Geological Survey Open-File Report 98-165, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments, 1998.


82 FIAlab Instruments, Inc. Method FIAlab 100, “Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Fluorescence Detector Analysis”, April 4, 2018, FIAlab Instruments, Inc.


83 MACHEREY-NAGEL GmbH and Co. Method 036/038 NANOCOLOR® COD LR/HR, “Spectrophotometric Measurement of Chemical Oxygen Demand in Water and Wastewater”, Revision 1.5, May 2018, MACHEREY-NAGEL GmbH and Co. KG.


84 Please refer to the following applicable Quality Control Sections: Part 2000 Methods, Physical and Aggregate Properties 2020 (2017); Part 3000 Methods, Metals, 3020 (2017); Part 4000 Methods, Inorganic Nonmetallic Constituents, 4020 (2014); Part 5000 Methods, and Aggregate Organic Constituents, 5020 (2017). These Quality Control Standards are available for download at www.standardmethods.org at no charge.


85 Each laboratory may establish its own control limits by performing at least 25 glucose-glutamic acid (GGA) checks over several weeks or months and calculating the mean and standard deviation. The laboratory may then use the mean ± 3 standard deviations as the control limit for future GGA checks. However, GGA acceptance criteria can be no wider than 198 ± 30.5 mg/L for BOD5. GGA acceptance criteria for CBOD must be either 198 ± 30.5 mg/L, or the lab may develop control charts under the following conditions:

• Dissolved oxygen uptake from the seed contribution is between 0.6-1.0 mg/L.

• Control charts are performed on at least 25 GGA checks with three standard deviations from the derived mean.

• The RSD must not exceed 7.5%.

• Any single GGA value cannot be less than 150 mg/L or higher than 250 mg/L.


Table IC—List of Approved Test Procedures for Non-Pesticide Organic Compounds

Parameter
1
Method
EPA
2
7
Standard

methods
ASTM
Other
1. AcenaphtheneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
2. AcenaphthyleneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
3. AcroleinGC603
GC/MS624.1,
4 1624B
4. AcrylonitrileGC603
GC/MS624.1,
4 1624B		O-4127-96.
13
5. AnthraceneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
6. BenzeneGC6026200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
7. BenzidineSpectrophoto-

metric		See footnote
3, p.1.
GC/MS625.1,
5 1625B		6410 B-2000
HPLC605
8. Benzo(a)anthraceneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
9. Benzo(a)pyreneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
10. Benzo(b)fluorantheneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
11. Benzo(g,h,i)peryleneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
12. Benzo(k)fluorantheneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
13. Benzyl chlorideGCSee footnote
3, p. 130.
GC/MSSee footnote
6, p. S102.
14. Butyl benzyl phthalateGC606
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
15. bis(2-Chloroethoxy) methaneGC611
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
16. bis(2-Chloroethyl) etherGC611
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
17. bis(2-Ethylhexyl) phthalateGC606
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
18. BromodichloromethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
19. BromoformGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
20. BromomethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
21. 4-Bromophenyl phenyl etherGC611
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
22. Carbon tetrachlorideGC6016200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
23. 4-Chloro-3-methyl phenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
24. ChlorobenzeneGC601, 6026200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
25. ChloroethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96.
13
26. 2-Chloroethylvinyl etherGC601
GC/MS624.1, 1624B
27. ChloroformGC6016200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
28. ChloromethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
29. 2-ChloronaphthaleneGC612
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
30. 2-ChlorophenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
31. 4-Chlorophenyl phenyl etherGC611
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
32. ChryseneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
33. Dibenzo(a,h)anthraceneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
34. DibromochloromethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
35. 1,2-DichlorobenzeneGC601, 6026200 C-2011
GC/MS624.1, 1625B6200 B-2011See footnote,
9 p. 27; O-4127-96,
13 O-4436-16.
14
36. 1,3-DichlorobenzeneGC601, 6026200 C-2011
GC/MS624.1, 1625B6200 B-2011See footnote
9, p. 27; O-4127-96.
13
37. 1,4-DichlorobenzeneGC601, 6026200 C-2011
GC/MS624.1, 1625B6200 B-2011See footnote,
9 p. 27; O-4127-96,
13 O-4436-16.
14
38. 3,3′-DichlorobenzidineGC/MS625.1, 1625B6410 B-2000
HPLC605
39. DichlorodifluoromethaneGC601
GC/MS6200 C-2011O-4127-96
13, O-4436-16.
14
40. 1,1-DichloroethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
41. 1,2-DichloroethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
42. 1,1-DichloroetheneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
43. trans-1,2-DichloroetheneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
44. 2,4-DichlorophenolGC6046420 B-2000.
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
45. 1,2-DichloropropaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
46. cis-1,3-DichloropropeneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
47. trans-1,3-DichloropropeneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
48. Diethyl phthalateGC606
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
49. 2,4-DimethylphenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
50. Dimethyl phthalateGC606
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
51. Di-n-butyl phthalateGC606
GC/MS625.1, 1625B6410 B-2000See footnote,
9, p. 27.
52. Di-n-octyl phthalateGC606
GC/MS625.1, 1625B6410 B-2000See footnote,
9 p. 27.
53. 2, 4-DinitrophenolGC6046420 B-2000See footnote
9, p. 27.
GC/MS625.1, 1625B6410 B-2000
54. 2,4-DinitrotolueneGC609
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
55. 2,6-DinitrotolueneGC609
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
56. EpichlorohydrinGCSee footnote
3, p. 130.
GC/MSSee footnote
6, p. S102.
57. EthylbenzeneGC6026200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96,
13 O-4436-16.
14
58. FluorantheneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
59. FluoreneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
60. 1,2,3,4,6,7,8-Heptachloro-dibenzofuranGC/MS1613B
61. 1,2,3,4,7,8,9-Heptachloro-dibenzofuranGC/MS1613B
62. 1,2,3,4,6,7,8-Heptachloro-dibenzo-p-dioxinGC/MS1613B
63. HexachlorobenzeneGC612
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
64. HexachlorobutadieneGC612
GC/MS625.1, 1625B6410 B-2000See footnote,
9 p. 27; O-4127-96.
13
65. HexachlorocyclopentadieneGC612
GC/MS625.1,
5 1625B		6410 B-2000See footnote,
9 p. 27; O-4127-96.
13
66. 1,2,3,4,7,8-Hexachloro-dibenzofuranGC/MS1613B
67. 1,2,3,6,7,8-Hexachloro-dibenzofuranGC/MS1613B
68. 1,2,3,7,8,9-Hexachloro-dibenzofuranGC/MS1613B
69. 2,3,4,6,7,8-Hexachloro-dibenzofuranGC/MS1613B
70. 1,2,3,4,7,8-Hexachloro-dibenzo-p-dioxinGC/MS1613B
71. 1,2,3,6,7,8-Hexachloro-dibenzo-p-dioxinGC/MS1613B
72. 1,2,3,7,8,9-Hexachloro-dibenzo-p-dioxinGC/MS1613B
73. HexachloroethaneGC612
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27; O-4127-96.
13
74. Indeno(1,2,3-c,d) pyreneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
75. IsophoroneGC609
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
76. Methylene chlorideGC6016200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
77. 2-Methyl-4,6-dinitrophenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
78. NaphthaleneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005
79. NitrobenzeneGC609
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLCD4657-92 (98)
80. 2-NitrophenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
81. 4-NitrophenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
82. N-NitrosodimethylamineGC607
GC/MS625.1,
5 1625B		6410 B-2000See footnote,
9 p. 27.
83. N-Nitrosodi-n-propylamineGC607
GC/MS625.1,
5 1625B		6410 B-2000See footnote,
9 p. 27.
84. N-NitrosodiphenylamineGC607
GC/MS625.1,
5 1625B		6410 B-2000See footnote,
9 p. 27.
85. OctachlorodibenzofuranGC/MS1613B.
10
86. Octachlorodibenzo-p-dioxinGC/MS1613B.
10
87. 2,2′-oxybis(1-chloropropane)
12 [also known as bis(2-Chloro-1-methylethyl) ether]		GC611
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
88. PCB-1016GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
89. PCB-1221GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
90. PCB-1232GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
91. PCB-1242GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
92. PCB-1248GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
93. PCB-1254GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
94. PCB-1260GC608.3See footnote
3, p. 43; See footnote.
8
GC/MS625.16410 B-2000
95. 1,2,3,7,8-Pentachloro-dibenzofuranGC/MS1613B
96. 2,3,4,7,8-Pentachloro-dibenzofuranGC/MS1613B
97. 1,2,3,7,8-Pentachloro-dibenzo-p-dioxinGC/MS1613B
98. PentachlorophenolGC6046420 B-2000See footnote
3, p. 140.
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
99. PhenanthreneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
100. PhenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
101. PyreneGC610
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
HPLC6106440 B-2005D4657-92 (98)
102. 2,3,7,8-Tetrachloro-dibenzofuranGC/MS1613B.
10
103. 2,3,7,8-Tetrachloro-dibenzo-p-dioxinGC/MS613, 625.1,
5a 1613B
104. 1,1,2,2-TetrachloroethaneGC6016200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96.
13
105. TetrachloroetheneGC6016200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
106. TolueneGC6026200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
107. 1,2,4-TrichlorobenzeneGC612See footnote
3, p. 130.
GC/MS625.1, 1625B6410 B-2000See footnote,
9 p. 27; O-4127-96,
13 O-4436-16.
14
108. 1,1,1-TrichloroethaneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
109. 1,1,2-TrichloroethaneGC6016200 C-2011See footnote
3, p. 130.
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
110. TrichloroetheneGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
111. TrichlorofluoromethaneGC6016200 C-2011
GC/MS624.16200 B-2011O-4127-96.
13
112. 2,4,6-TrichlorophenolGC6046420 B-2000
GC/MS625.1, 1625B6410 B-2000See footnote
9, p. 27.
113. Vinyl chlorideGC6016200 C-2011
GC/MS624.1, 1624B6200 B-2011O-4127-96
13, O-4436-16.
14
114. NonylphenolGC/MSD7065-17
115. Bisphenol A (BPA)GC/MSD7065-17
116. p-tert-Octylphenol (OP)GC/MSD7065-17
117. Nonylphenol Monoethoxylate (NP1EO)GC/MSD7065-17
118. Nonylphenol Diethoxylate (NP2EO)GC/MSD7065-17
119. Adsorbable Organic Halides (AOX)Adsorption and Coulometric Titration1650.
11
120. Chlorinated PhenolicsIn Situ Acetylation and GC/MS1653.
11

Table IC notes:


1 All parameters are expressed in micrograms per liter (µg/L) except for Method 1613B, in which the parameters are expressed in picograms per liter (pg/L).


2 The full text of Methods 601-613, 1613B, 1624B, and 1625B are provided at appendix A, Test Procedures for Analysis of Organic Pollutants. The standardized test procedure to be used to determine the method detection limit (MDL) for these test procedures is given at appendix B of this part, Definition and Procedure for the Determination of the Method Detection Limit. These methods are available at: https://www.epa.gov/cwa-methods as individual PDF files.


3 Methods for Benzidine: Chlorinated Organic Compounds, Pentachlorophenol and Pesticides in Water and Wastewater. September 1978. U.S. EPA.


4 Method 624.1 may be used for quantitative determination of acrolein and acrylonitrile, provided that the laboratory has documentation to substantiate the ability to detect and quantify these analytes at levels necessary to comply with any associated regulations. In addition, the use of sample introduction techniques other than simple purge-and-trap may be required. QC acceptance criteria from Method 603 should be used when analyzing samples for acrolein and acrylonitrile in the absence of such criteria in Method 624.1.


5 Method 625.1 may be extended to include benzidine, hexachlorocyclopentadiene, N-nitrosodimethylamine, N-nitrosodi-n-propylamine, and N-nitrosodiphenylamine. However, when they are known to be present, Methods 605, 607, and 612, or Method 1625B, are preferred methods for these compounds.


5a Method 625.1 screening only.


6 Selected Analytical Methods Approved and Cited by the United States Environmental Protection Agency, Supplement to the 15th Edition of Standard Methods for the Examination of Water and Wastewater. 1981. American Public Health Association (APHA).


7 Each analyst must make an initial, one-time demonstration of their ability to generate acceptable precision and accuracy with Methods 601-603, 1624B, and 1625B in accordance with procedures in Section 8.2 of each of these methods. Additionally, each laboratory, on an on-going basis must spike and analyze 10% (5% for Methods 624.1 and 625.1 and 100% for methods 1624B and 1625B) of all samples to monitor and evaluate laboratory data quality in accordance with Sections 8.3 and 8.4 of these methods. When the recovery of any parameter falls outside the quality control (QC) acceptance criteria in the pertinent method, analytical results for that parameter in the unspiked sample are suspect. The results should be reported but cannot be used to demonstrate regulatory compliance. If the method does not contain QC acceptance criteria, control limits of ± three standard deviations around the mean of a minimum of five replicate measurements must be used. These quality control requirements also apply to the Standard Methods, ASTM Methods, and other methods cited.


8 Organochlorine Pesticides and PCBs in Wastewater Using Empore
TM Disk. Revised October 28, 1994. 3M Corporation.


9 Method O-3116-87 is in Open File Report 93-125, Methods of Analysis by U.S. Geological Survey National Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments. 1993. USGS.


10 Analysts may use Fluid Management Systems, Inc. Power-Prep system in place of manual cleanup provided the analyst meets the requirements of Method 1613B (as specified in Section 9 of the method) and permitting authorities. Method 1613, Revision B, Tetra- through Octa-Chlorinated Dioxins and Furans by Isotope Dilution HRGC/HRMS. Revision B, 1994. U.S. EPA. The full text of this method is provided in appendix A to this part and at https://www.epa.gov/cwa-methods/approved-cwa-test-methods-organic-compounds.


11 Method 1650, Adsorbable Organic Halides by Adsorption and Coulometric Titration. Revision C, 1997 U.S. EPA. Method 1653, Chlorinated Phenolics in Wastewater by In Situ Acetylation and GCMS. Revision A, 1997 U.S. EPA. The full text for both of these methods is provided at appendix A in part 430 of this chapter, The Pulp, Paper, and Paperboard Point Source Category.


12 The compound was formerly inaccurately labeled as 2,2′-oxybis(2-chloropropane) and bis(2-chloroisopropyl) ether. Some versions of Methods 611, and 1625 inaccurately list the analyte as “bis(2-chloroisopropyl)ether,” but use the correct CAS number of 108-60-1.


13 Method O-4127-96, U.S. Geological Survey Open-File Report 97-829, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of 86 volatile organic compounds in water by gas chromatography/mass spectrometry, including detections less than reporting limits,1998, USGS.


14 Method O-4436-16 U.S. Geological Survey Techniques and Methods, book 5, chap. B12, Determination of heat purgeable and ambient purgeable volatile organic compounds in water by gas chromatography/mass spectrometry, 2016, USGS.


Table ID—List of Approved Test Procedures for Pesticides
1

Parameter
Method
EPA
2 7 10
Standard methods
ASTM
Other
1. AldrinGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96 (02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS625.16410 B-2000
2. AmetrynGC507, 619See footnote,
3 p. 83; See footnote,
9 O-3106-93; See footnote,
6 p. S68.
GC/MS525.2, 625.1See footnote,
14 O-1121-91.
3. AminocarbTLCSee footnote,
3 p. 94; See footnote,
6 p. S60.
HPLC632
4. AtratonGC619See footnote,
3 p. 83; See footnote,
6 p. S68.
GC/MS625.1
5. AtrazineGC507, 619, 608.3See footnote,
3 p. 83; See footnote,
6 p. S68; See footnote,
9 O-3106-93.
HPLC/MSSee footnote,
12 O-2060-01.
GC/MS525.1, 525.2, 625.1See footnote,
11 O-1126-95.
6. Azinphos methylGC614, 622, 1657See footnote,
3 p. 25; See footnote,
6 p. S51.
GC/MS625.1See footnote,
11 O-1126-95.
7. BarbanTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
GC/MS625.1
8. α-BHCGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
8 3M0222.
GC/MS625.1
5		6410 B-2000See footnote,
11 O-1126-95.
9. β-BHCGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
8 3M0222.
GC/MS625.16410 B-2000
10. δ-BHCGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
8 3M0222.
GC/MS625.16410 B-2000
11. γ-BHC (Lindane)GC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS625.1
5		6410 B-2000See footnote,
11 O-1126-95.
12. CaptanGC617, 608.36630 B-2007D3086-90, D5812-96(02)See footnote,
3 p. 7.
13. CarbarylTLCSee footnote,
3 p. 94, See footnote,
6 p. S60.
HPLC531.1, 632
HPLC/MS553See footnote,
12 O-2060-01.
GC/MS625.1See footnote,
11 O-1126-95.
14. CarbophenothionGC617, 608.36630 B-2007See footnote,
4 page 27; See footnote,
6 p. S73.
GC/MS625.1
15. ChlordaneGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS625.16410 B-2000
16. ChloroprophamTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
GC/MS625.1
17. 2,4-DGC6156640 B-2006See footnote,
3 p. 115; See footnote,
4 O-3105-83.
HPLC/MSSee footnote,
12 O-2060-01.
18. 4,4′-DDDGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3105-83; See footnote,
8 3M0222.
GC/MS625.16410 B-2000
19. 4,4′-DDEGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS625.16410 B-2000See footnote,
11 O-1126-95.
20. 4,4′-DDTGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS625.16410 B-2000
21. Demeton-OGC614, 622See footnote,
3 p. 25; See footnote,
6 p. S51.
GC/MS625.1
22. Demeton-SGC614, 622See footnote,
3 p. 25; See footnote,
6 p. S51.
GC/MS625.1
23. DiazinonGC507, 614, 622, 1657See footnote,
3 p. 25; See footnote,
4 O-3104-83; See footnote,
6 p. S51.
GC/MS525.2, 625.1See footnote,
11 O-1126-95.
24. DicambaGC615See footnote,
3 p. 115.
HPLC/MSSee footnote,
12 O-2060-01.
25. DichlofenthionGC622.1See footnote,
4 page 27; See footnote,
6 p. S73.
26. DichloranGC608.2, 617, 608.36630 B-2007See footnote,
3 p. 7.
27. DicofolGC617, 608.3See footnote,
4 O-3104-83.
28. DieldrinGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS625.16410 B-2000See footnote,
11 O-1126-95.
29. DioxathionGC614.1, 1657See footnote,
4 page 27; See footnote,
6 p. S73.
30. DisulfotonGC507, 614, 622, 1657See footnote,
3 p. 25; See footnote,
6 p. S51.
GC/MS525.2, 625.1See footnote,
11 O-1126-95.
31. DiuronTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
HPLC/MS553See footnote,
12 O-2060-01.
32. Endosulfan IGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222).
GC/MS625.1
5		6410 B-2000See footnote,
13 O-2002-01.
33. Endosulfan IIGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
8 3M0222.
GC/MS625.1
5		6410 B-2000See footnote,
13 O-2002-01.
34. Endosulfan SulfateGC617, 608.36630 C-2007See footnote,
8 3M0222.
GC/MS625.16410 B-2000
35. EndrinGC505, 508, 617, 1656, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS525.1, 525.2, 625.1
5		6410 B-2000
36. Endrin aldehydeGC617, 608.36630 C-2007See footnote,
8 3M0222.
GC/MS625.1
37. EthionGC614, 614.1, 1657See footnote,
4 page 27; See footnote,
6 p. S73.
GC/MS625.1See footnote,
13 O-2002-01.
38. FenuronTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
HPLC/MSSee footnote,
12 O-2060-01.
39. Fenuron-TCATLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
40. HeptachlorGC505, 508, 617, 1656, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS525.1, 525.2, 625.16410 B-2000
41. Heptachlor epoxideGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
6 p. S73; See footnote,
8 3M0222.
GC/MS625.16410 B-2000
42. IsodrinGC617, 608.36630 B-2007 & C-2007See footnote,
4 O-3104-83; See footnote,
6 p. S73.
GC/MS625.1
43. LinuronGCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
HPLC/MS553See footnote,
12 O-2060-01.
GC/MSSee footnote,
11 O-1126-95.
44. MalathionGC614, 16576630 B-2007See footnote,
3 p. 25; See footnote,
6 p. S51.
GC/MS625.1See footnote,
11 O-1126-95.
45. MethiocarbTLCSee footnote,
3 p. 94; See footnote,
6 p. S60.
HPLC632
HPLC/MSSee footnote,
12 O-2060-01.
46. MethoxychlorGC505, 508, 608.2, 617, 1656, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83; See footnote,
8 3M0222.
GC/MS525.1, 525.2, 625.1See footnote,
11 O-1126-95.
47. MexacarbateTLCSee footnote,
3 p. 94; See footnote,
6 p. S60.
HPLC632
GC/MS625.1
48. MirexGC617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote,
4 O-3104-83.
GC/MS625.1
49. MonuronTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
50. Monuron-TCATLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
51. NeburonTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
HPLC/MSSee footnote,
12 O-2060-01.
52. Parathion methylGC614, 622, 16576630 B-2007See footnote,
4 page 27; See footnote,
3 p. 25.
GC/MS625.1See footnote,
11 O-1126-95.
53. Parathion ethylGC6146630 B-2007See footnote,
4 page 27; See footnote,
3 p. 25.
GC/MSSee footnote,
11 O-1126-95.
54. PCNBGC608.1, 617, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7.
55. PerthaneGC617, 608.3D3086-90, D5812-96(02)See footnote,
4 O-3104-83.
56. PrometonGC507, 619See footnote,
3 p. 83; See footnote,
6 p. S68; See footnote,
9 O-3106-93.
GC/MS525.2, 625.1See footnote,
11 O-1126-95.
57. PrometrynGC507, 619See footnote,
3 p. 83; See footnote,
6 p. S68; See footnote,
9 O-3106-93.
GC/MS525.1, 525.2, 625.1See footnote,
13 O-2002-01.
58. PropazineGC507, 619, 1656, 608.3See footnote,
3 p. 83; See footnote,
6 p. S68; See footnote,
9 O-3106-93.
GC/MS525.1, 525.2, 625.1
59. ProphamTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
HPLC/MSSee footnote,
12 O-2060-01.
60. PropoxurTLCSee footnote,
3 p. 94; See footnote,
6 p. S60.
HPLC632
61. SecbumetonTLCSee footnote,
3 p. 83; See footnote,
6 p. S68.
GC619
62. SiduronTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
HPLC/MSSee footnote,
12 O-2060-01.
63. SimazineGC505, 507, 619, 1656, 608.3See footnote,
3 p. 83; See footnote,
6 p. S68; See footnote,
9 O-3106-93.
GC/MS525.1, 525.2, 625.1See footnote,
11 O-1126-95.
64. StrobaneGC617, 608.36630 B-2007 & C-2007See footnote,
3 p. 7.
65. SwepTLCSee footnote,
3 p. 104; See footnote,
6 p. S64.
HPLC632
66. 2,4,5-TGC6156640 B-2006See footnote,
3 p. 115; See footnote,
4 O-3105-83.
67. 2,4,5-TP (Silvex)GC6156640 B-2006See footnote,
3 p. 115; See footnote,
4 O-3105-83.
68. TerbuthylazineGC619, 1656, 608.3See footnote,
3 p. 83; See footnote,
6 p. S68.
GC/MSSee footnote,
13 O-2002-01.
69. ToxapheneGC505, 508, 617, 1656, 608.36630 B-2007 & C-2007D3086-90, D5812-96(02)See footnote,
3 p. 7; See footnote;
8 See footnote,
4 O-3105-83.
GC/MS525.1, 525.2, 625.16410 B-2000
70. TrifluralinGC508, 617, 627, 1656, 608.36630 B-2007See footnote,
3 p. 7; See footnote,
9 O-3106-93.
GC/MS525.2, 625.1See footnote,
11 O-1126-95.

Table ID notes:


1 Pesticides are listed in this table by common name for the convenience of the reader. Additional pesticides may be found under Table IC of this section, where entries are listed by chemical name.


2 The standardized test procedure to be used to determine the method detection limit (MDL) for these test procedures is given at appendix B of this part, Definition and Procedure for the Determination of the Method Detection Limit.


3 Methods for Benzidine, Chlorinated Organic Compounds, Pentachlorophenol and Pesticides in Water and Wastewater. September 1978. U.S. EPA. This EPA publication includes thin-layer chromatography (TLC) methods.


4 Methods for the Determination of Organic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A3. 1987. USGS.


5 The method may be extended to include α-BHC, γ-BHC, endosulfan I, endosulfan II, and endrin. However, when they are known to exist, Method 608.3 is the preferred method.


6 Selected Analytical Methods Approved and Cited by the United States Environmental Protection Agency, Supplement to the 15th Edition of Standard Methods for the Examination of Water and Wastewater. 1981. American Public Health Association (APHA).


7 Each analyst must make an initial, one-time, demonstration of their ability to generate acceptable precision and accuracy with Methods 608.3 and 625.1 in accordance with procedures given in Section 8.2 of each of these methods. Additionally, each laboratory, on an on-going basis, must spike and analyze 5% of all samples analyzed with Method 608.3 or 5% of all samples analyzed with Method 625.1 to monitor and evaluate laboratory data quality in accordance with Sections 8.3 and 8.4 of these methods. When the recovery of any parameter falls outside the warning limits, the analytical results for that parameter in the unspiked sample are suspect. The results should be reported, but cannot be used to demonstrate regulatory compliance. These quality control requirements also apply to the Standard Methods, ASTM Methods, and other methods cited.


8 Organochlorine Pesticides and PCBs in Wastewater Using Empore
TM Disk. Revised October 28, 1994. 3M Corporation.


9 Method O-3106-93 is in Open File Report 94-37, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Triazine and Other Nitrogen-Containing Compounds by Gas Chromatography With Nitrogen Phosphorus Detectors. 1994. USGS.


10 EPA Methods 608.1, 608.2, 614, 614.1, 615, 617, 619, 622, 622.1, 627, and 632 are found in Methods for the Determination of Nonconventional Pesticides in Municipal and Industrial Wastewater, EPA 821-R-92-002, April 1992, U.S. EPA. EPA Methods 505, 507, 508, 525.1, 531.1 and 553 are in Methods for the Determination of Nonconventional Pesticides in Municipal and Industrial Wastewater, Volume II, EPA 821-R-93-010B, 1993, U.S. EPA. EPA Method 525.2 is in Determination of Organic Compounds in Drinking Water by Liquid-Solid Extraction and Capillary Column Gas Chromatography/Mass Spectrometry, Revision 2.0, 1995, U.S. EPA. EPA methods 1656 and 1657 are in Methods for the Determination of Nonconventional Pesticides in Municipal and Industrial Wastewater, Volume I, EPA 821-R-93-010A, 1993, U.S. EPA. Methods 608.3 and 625.1 are available at https://www.epa.gov/cwa-methods/approved-cwa-test-methods-organic-compounds.


11 Method O-1126-95 is in Open-File Report 95-181, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring. 1995. USGS.


12 Method O-2060-01 is in Water-Resources Investigations Report 01-4134, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Pesticides in Water by Graphitized Carbon-Based Solid-Phase Extraction and High-Performance Liquid Chromatography/Mass Spectrometry. 2001. USGS.


13 Method O-2002-01 is in Water-Resources Investigations Report 01-4098, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of moderate-use pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry. 2001. USGS.


14 Method O-1121-91 is in Open-File Report 91-519, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring. 1992. USGS.


Table IE—List of Approved Radiologic Test Test Procedures

Parameter and units
Method
Reference (method number or page)
EPA
1
Standard Methods 18th, 19th, 20th Ed.
Standard Methods Online
ASTM
USGS
2
1. Alpha-Total, pCi per literProportional or scintillation counter900.07110 B7110 B-00D1943-90, 96pp. 75 and 78
3
2. Alpha-Counting error, pCi per literProportional or scintillation counterAppendix B7110 B7110 B-00D1943-90, 96p. 79
3. Beta-Total, pCi per literProportional counter900.07110 B7110 B-00D1890-90, 96pp. 75 and 78
3
4. Beta-Counting error, pCiProportional counterAppendix B7110 B7110 B-00D1890-90, 96p. 79
5. (a) Radium Total pCi per liter

(b) Ra, pCi per liter		Proportional counter903.07500-Ra B7500-Ra B-01D2460-90, 97
Scintillation counter903.17500-Ra C7500-Ra C-01D3454-91, 97p. 81


1 Prescribed Procedures for Measurement of Radioactivity in Drinking Water, EPA-600/4-80-032 (1980), U.S. Environmental Protection Agency, August 1980.


2 Fishman, M. J. and Brown, Eugene, “Selected Methods of the U.S. Geological Survey of Analysis of Wastewaters,” U.S. Geological Survey, Open-File Report 76-177 (1976).


3 The method found on p. 75 measures only the dissolved portion while the method on p. 78 measures only the suspended portion. Therefore, the two results must be added to obtain the “total.”


Table IF—List of Approved Methods for Pharmaceutical Pollutants

Pharmaceuticals pollutants
CAS registry No.
Analytical method number
Acetonitrile75-05-81666/1671/D3371/D3695/624.1
n-Amyl acetate628-63-71666/D3695
n-Amyl alcohol71-41-01666/D3695
Benzene71-43-2D4763/D3695/502.2/524.2/624.1
n-Butyl-acetate123-86-41666/D3695
tert-Butyl alcohol75-65-01666/624.1
Chlorobenzene108-90-7502.2/524.2/624.1
Chloroform67-66-3502.2/524.2/551/624.1
o-Dichlorobenzene95-50-11625C/502.2/524.2/624.1
1,2-Dichloroethane107-06-2D3695/502.2/524.2/624.1
Diethylamine109-89-71666/1671
Dimethyl sulfoxide67-68-51666/1671
Ethanol64-17-51666/1671/D3695/624.1
Ethyl acetate141-78-61666/D3695/624.1
n-Heptane142-82-51666/D3695
n-Hexane110-54-31666/D3695
Isobutyraldehyde78-84-21666/1667
Isopropanol67-63-01666/D3695
Isopropyl acetate108-21-41666/D3695
Isopropyl ether108-20-31666/D3695
Methanol67-56-11666/1671/D3695/624.1
Methyl Cellosolve® (2-Methoxy ethanol)109-86-41666/1671
Methylene chloride75-09-2502.2/524.2/624.1
Methyl formate107-31-31666
4-Methyl-2-pentanone (MIBK)108-10-11624C/1666/D3695/D4763/524.2/624.1
Phenol108-95-2D4763
n-Propanol71-23-81666/1671/D3695/624.1
2-Propanone (Acetone)67-64-1D3695/D4763/524.2/624.1
Tetrahydrofuran109-99-91666/524.2/624.1
Toluene108-88-3D3695/D4763/502.2/524.2/624.1
Triethlyamine121-44-81666/1671
Xylenes(Note 1)1624C/1666/624.1

Table IF note:


1 1624C: m-xylene 108-38-3, o,p-xylene, E-14095 (Not a CAS number; this is the number provided in the Environmental Monitoring Methods Index [EMMI] database.); 1666: m,p-xylene 136777-61-2, o-xylene 95-47-6.


Table IG—Test Methods for Pesticide Active Ingredients

[40 CFR part 455]

EPA survey code
Pesticide name
CAS No.
EPA analytical method No.(s)
3
8Triadimefon43121-43-3507/633/525.1/525.2/1656/625.1.
12Dichlorvos62-73-71657/507/622/525.1/525.2/625.1.
162,4-D; 2,4-D Salts and Esters [2,4-Dichloro-phenoxyacetic acid]94-75-71658/515.1/615/515.2/555.
172,4-DB; 2,4-DB Salts and Esters [2,4-Dichlorophenoxybutyric acid]94-82-61658/515.1/615/515.2/555.
22Mevinphos7786-34-71657/507/622/525.1/525.2/625.1.
25Cyanazine21725-46-2629/507/608.3/625.1.
26Propachlor1918-16-71656/508/608.1/525.1/525.2/608.3/625.1.
27MCPA; MCPA Salts and Esters

[2-Methyl-4-chlorophenoxyacetic acid]		94-74-61658/615/555.
30Dichlorprop; Dichlorprop Salts and Esters [2-(2,4-Dichlorophenoxy) propionic acid]120-36-51658/515.1/615/515.2/555.
31MCPP; MCPP Salts and Esters [2-(2-Methyl-4-chlorophenoxy) propionic acid]93-65-21658/615/555.
35TCMTB [2-(Thiocyanomethylthio) benzo-thiazole]21564-17-0637.
39Pronamide23950-58-5525.1/525.2/507/633.1/625.1.
41Propanil709-98-8632.1/1656/608.3.
45Metribuzin21087-64-9507/633/525.1/525.2/1656/608.3/625.1.
52Acephate30560-19-11656/1657/608.3.
53Acifluorfen50594-66-6515.1/515.2/555.
54Alachlor15972-60-8505/507/645/525.1/525.2/1656/608.3/625.1.
55Aldicarb116-06-3531.1.
58Ametryn834-12-8507/619/525.2/625.1.
60Atrazine1912-24-9505/507/619/525.1/525.2/1656/ 608.3/625.1.
62Benomyl17804-35-2631.
68Bromacil; Bromacil Salts and Esters314-40-9507/633/525.1/525.2/1656/608.3/625.1.
69Bromoxynil1689-84-51625/1661/625.1.
69Bromoxynil Octanoate1689-99-21656/608.3.
70Butachlor23184-66-9507/645/525.1/525.2/1656/608.3/625.1.
73Captafol2425-06-11656/608.3/625.1.
75Carbaryl [Sevin]63-25-2531.1/632/553/625.1.
76Carbofuran1563-66-2531.1/632/625.1.
80Chloroneb2675-77-61656/508/608.1/525.1/525.2/608.3/625.1.
82Chlorothalonil1897-45-6508/608.2/525.1/525.2/1656/608.3/625.1.
84Stirofos961-11-51657/507/622/525.1/525.2/625.1.
86Chlorpyrifos2921-88-21657/508/622/625.1.
90Fenvalerate51630-58-11660.
103Diazinon333-41-51657/507/614/622/525.2/625.1.
107Parathion methyl298-00-01657/614/622/625.1.
110DCPA [Dimethyl 2,3,5,6-tetrachloro-terephthalate]1861-32-1508/608.2/525.1/525.2/515.1
2/515.2
2/1656/608.3/625.1.
112Dinoseb88-85-71658/515.1/615/515.2/555/625.1.
113Dioxathion78-34-21657/614.1.
118Nabonate [Disodium cyanodithio-imidocarbonate]138-93-2630.1.
119Diuron330-54-1632/553.
123Endothall145-73-3548/548.1.
124Endrin72-20-81656/505/508/617/525.1/525.2/608.3/625.1.
125Ethalfluralin55283-68-61656/627/608.3 See footnote 1.
126Ethion563-12-21657/614/614.1/625.1.
127Ethoprop13194-48-41657/507/622/525.1/525.2/625.1.
132Fenarimol60168-88-9507/633.1/525.1/525.2/1656/608.3/625.1.
133Fenthion55-38-91657/622/625.1.
138Glyphosate [N-(Phosphonomethyl) glycine]1071-83-6547.
140Heptachlor76-44-81656/505/508/617/525.1/525.2/608.3/625.1.
144Isopropalin33820-53-01656/627/608.3.
148Linuron330-55-2553/632.
150Malathion121-75-51657/614/625.1.
154Methamidophos10265-92-61657.
156Methomyl16752-77-5531.1/632.
158Methoxychlor72-43-51656/505/508/608.2/617/525.1/525.2/608.3/625.1.
172Nabam142-59-6630/630.1.
173Naled300-76-51657/622/625.1.
175Norflurazon27314-13-2507/645/525.1/525.2/1656/608.3/625.1.
178Benfluralin1861-40-11656/627/608.3 See footnote 1.
182Fensulfothion115-90-21657/622/625.1.
183Disulfoton298-04-41657/507/614/622/525.2/625.1.
185Phosmet732-11-61657/622.1/625.1.
186Azinphos Methyl86-50-01657/614/622/625.1.
192Organo-tin pesticides12379-54-3Ind-01/200.7/200.9.
197Bolstar35400-43-21657/622.
203Parathion56-38-21657/614/625.1.
204Pendimethalin40487-42-11656.
205Pentachloronitrobenzene82-68-81656/608.1/617/608.3/625.1.
206Pentachlorophenol87-86-51625/515.2/555/515.1/525.1/525.2/625.1.
208Permethrin52645-53-1608.2/508/525.1/525.2/1656/1660/608.3
4/625.1
4.
212Phorate298-02-21657/622/625.1.
218Busan 85 [Potassium dimethyldithiocarbamate]128-03-0630/630.1.
219Busan 40 [Potassium N-hydroxymethyl-N-methyldithiocarbamate]51026-28-9630/630.1.
220KN Methyl [Potassium N-methyl-dithiocarbamate]137-41-7630/630.1.
223Prometon1610-18-0507/619/525.2/625.1.
224Prometryn7287-19-6507/619/525.1/525.2/625.1.
226Propazine139-40-2507/619/525.1/525.2/1656/608.3/625.1.
230Pyrethrin I121-21-11660.
232Pyrethrin II121-29-91660.
236DEF [S,S,S-Tributyl phosphorotrithioate]78-48-81657.
239Simazine122-34-9505/507/619/525.1/525.2/1656/608.3/625.1.
241Carbam-S [Sodium dimethyldithio-carbamate]128-04-1630/630.1.
243Vapam [Sodium methyldithiocarbamate]137-42-8630/630.1.
252Tebuthiuron34014-18-1507/525.1/525.2/625.1.
254Terbacil5902-51-2507/633/525.1/525.2/1656/608.3/625.1.
255Terbufos13071-79-91657/507/614.1/525.1/525.2/625.1.
256Terbuthylazine5915-41-3619/1656/608.3.
257Terbutryn886-50-0507/619/525.1/525.2/625.1.
259Dazomet533-74-4630/630.1/1659.
262Toxaphene8001-35-21656/505/508/617/525.1/525.2/608.3/625.1.
263Merphos [Tributyl phosphorotrithioate]150-50-51657/507/525.1/525.2/622/625.1.
264Trifluralin
1		1582-09-81656/508/617/627/525.2/608.3/625.1.
268Ziram [Zinc dimethyldithiocarbamate]137-30-4630/630.1.

Table IG notes:


1 Monitor and report as total Trifluralin.


2 Applicable to the analysis of DCPA degradates.


3 EPA Methods 608.1 through 645, 1645 through 1661, and Ind-01 are available in Methods for the Determination of Nonconventional Pesticides in Municipal and Industrial Wastewater, Volume I, EPA 821-R-93-010A, Revision I, August 1993, U.S. EPA. EPA Methods 200.9 and 505 through 555 are available in Methods for the Determination of Nonconventional Pesticides in Municipal and Industrial Wastewater, Volume II, EPA 821-R-93-010B, August 1993, U.S. EPA. The full text of Methods 608.3, 625.1, and 1625 are provided at appendix A of this part. The full text of Method 200.7 is provided at appendix C of this part. Methods 608.3 and 625.1 are available at https://www.epa.gov/cwa-methods/approved-cwa-test-methods-organic-compounds.


4 Permethrin is not listed within methods 608.3 and 625.1; however, cis-permethrin and trans-permethrin are listed. Permethrin can be calculated by adding the results of cis- and trans-permethrin.


Table IH—List of Approved Microbiological Methods for Ambient Water

Parameter and units
Method
1
EPA
Standard methods
AOAC, ASTM, USGS
Other
Bacteria
1. Coliform (fecal), number per 100 mLMost Probable Number (MPN), 5 tube, 3 dilution, orp. 132 39221 E-2014, 9221 F-2014 32
Membrane filter (MF) 2, single stepp. 124 39222 D-2015 26B-0050-85 4
2. Coliform (total), number per 100 mLMPN, 5 tube, 3 dilution, orp. 114 39221 B-2014B-0025-85 4
MF 2, single step or two stepp. 108 39222 B-2015 27
MF 2 with enrichmentp. 111 39222 B- 2015 27
3. E. coli, number per 100 mLMPN 5 7 13, multiple tube, or9221 B.3-2014/9221 F-2014 10 12 32
Multiple tube/multiple well, or9223 B-2016 11991.15 9Colilert® 11 15, Colilert-18®.11 14 15
MF 2 5 6 7, two step, or1103.1 189222 B-2015/9222 I-2015 17, 9213 D-2007D5392-93 8
Single step1603 19, 1604 20m-ColiBlue24® 16, KwikCountTM EC. 28 29
4. Fecal streptococci, number per 100 mLMPN, 5 tube, 3 dilution, orp. 139 39230 B-2013B-0055-85 4
MF 2, orp. 136 39230 C-2013 30
Plate countp. 143 3
5. Enterococci, number per 100 mLMPN 5 7, multiple tube/multiple well, or 9230 D-2013D6503-99 8Enterolert®.11 21
MF 2 5 6 7 two step, or1106.1 229230 C-2013 30D5259-92 8
Single step, or1600 239230 C-2013 30
Plate countp. 143 3
Protozoa
6. CryptosporidiumFiltration/IMS/FA1622 24, 1623 25, 1623.1 25 31
7. GiardiaFiltration/IMS/FA1623 25, 1623.1 25 31

Table 1H notes:


1 The method must be specified when results are reported.


2 A 0.45-µm membrane filter (MF) or other pore size certified by the manufacturer to fully retain organisms to be cultivated and to be free of extractables which could interfere with their growth.


3 Microbiological Methods for Monitoring the Environment, Water and Wastes. EPA/600/8-78/017. 1978. US EPA.


4 U.S. Geological Survey Techniques of Water-Resource Investigations, Book 5, Laboratory Analysis, Chapter A4, Methods for Collection and Analysis of Aquatic Biological and Microbiological Samples. 1989. USGS.


5 Tests must be conducted to provide organism enumeration (density). Select the appropriate configuration of tubes/filtrations and dilutions/volumes to account for the quality, character, consistency, and anticipated organism density of the water sample.


6 When the MF method has not been used previously to test waters with high turbidity, large numbers of noncoliform bacteria, or samples that may contain organisms stressed by chlorine, a parallel test should be conducted with a multiple-tube technique to demonstrate applicability and comparability of results.


7 To assess the comparability of results obtained with individual methods, it is suggested that side-by-side tests be conducted across seasons of the year with the water samples routinely tested in accordance with the most current Standard Methods for the Examination of Water and Wastewater or EPA alternate test procedure (ATP) guidelines.


8 Annual Book of ASTM Standards—Water and Environmental Technology. Section 11.02. 2000, 1999, 1996. ASTM International.


9 Official Methods of Analysis of AOAC International, 16th Edition, Volume I, Chapter 17. 1995. AOAC International.


10 The multiple-tube fermentation test is used in 9221B.3-2014. Lactose broth may be used in lieu of lauryl tryptose broth (LTB), if at least 25 parallel tests are conducted between this broth and LTB using the water samples normally tested, and this comparison demonstrates that the false-positive rate and false-negative rate for total coliform using lactose broth is less than 10 percent. No requirement exists to run the completed phase on 10 percent of all total coliform-positive tubes on a seasonal basis.


11 These tests are collectively known as defined enzyme substrate tests.


12 After prior enrichment in a presumptive medium for total coliform using 9221B.3-2014, all presumptive tubes or bottles showing any amount of gas, growth or acidity within 48 h ± 3 h of incubation shall be submitted to 9221F-2014. Commercially available EC-MUG media or EC media supplemented in the laboratory with 50 µg/mL of MUG may be used.


13 Samples shall be enumerated by the multiple-tube or multiple-well procedure. Using multiple-tube procedures, employ an appropriate tube and dilution configuration of the sample as needed and report the Most Probable Number (MPN). Samples tested with Colilert® may be enumerated with the multiple-well procedures, Quanti-Tray® or Quanti-Tray®/2000, and the MPN calculated from the table provided by the manufacturer.


14 Colilert-18® is an optimized formulation of the Colilert® for the determination of total coliforms and E. coli that provides results within 18 h of incubation at 35 °C, rather than the 24 h required for the Colilert® test, and is recommended for marine water samples.


15 Descriptions of the Colilert®, Colilert-18®, Quanti-Tray®, and Quanti-Tray®/2000 may be obtained from IDEXX Laboratories Inc.


16 A description of the mColiBlue24® test may be obtained from Hach Company.


17 Subject coliform positive samples determined by 9222B-2015 or other membrane filter procedure to 9222I-2015 using NA-MUG media.


18 Method 1103.1: Escherichia coli (E. coli) in Water by Membrane Filtration Using membrane-Thermotolerant Escherichia coli Agar (mTEC), EPA-821-R-10-002. March 2010. US EPA.


19 Method 1603: Escherichia coli (E. coli) in Water by Membrane Filtration Using Modified membrane-Thermotolerant Escherichia coli Agar (Modified mTEC), EPA-821-R-14-010. September 2014. US EPA.


20 Method 1604: Total Coliforms and Escherichia coli (E. coli) in Water by Membrane Filtration by Using a Simultaneous Detection Technique (MI Medium), EPA 821-R-02-024. September 2002. US EPA.


21 A description of the Enterolert® test may be obtained from IDEXX Laboratories Inc.


22 Method 1106.1: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus-Esculin Iron Agar (mE-EIA), EPA-821-R-09-015. December 2009. US EPA.


23 Method 1600: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus Indoxyl-β-D-Glucoside Agar (mEI), EPA-821-R-14-011. September 2014. US EPA.


24 Method 1622 uses a filtration, concentration, immunomagnetic separation of oocysts from captured material, immunofluorescence assay to determine concentrations, and confirmation through vital dye staining and differential interference contrast microscopy for the detection of Cryptosporidium. Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, EPA-821-R-05-001. December 2005. US EPA.


25 Methods 1623 and 1623.1 use a filtration, concentration, immunomagnetic separation of oocysts and cysts from captured material, immunofluorescence assay to determine concentrations, and confirmation through vital dye staining and differential interference contrast microscopy for the simultaneous detection of Cryptosporidium and Giardia oocysts and cysts. Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA. EPA-821-R-05-002. December 2005. US EPA. Method 1623.1: Cryptosporidium and Giardia in Water by Filtration/IMS/FA. EPA 816-R-12-001. January 2012. US EPA.


26 On a monthly basis, at least ten blue colonies from positive samples must be verified using Lauryl Tryptose Broth and EC broth, followed by count adjustment based on these results; and representative non-blue colonies should be verified using Lauryl Tryptose Broth. Where possible, verifications should be done from randomized sample sources.


27 On a monthly basis, at least ten sheen colonies from positive samples must be verified using Lauryl Tryptose Broth and brilliant green lactose bile broth, followed by count adjustment based on these results; and representative non-sheen colonies should be verified using Lauryl Tryptose Broth. Where possible, verifications should be done from randomized sample sources.


28 A description of KwikCountTM EC may be obtained from Micrology Laboratories LLC.


29 Approved for the analyses of E. coli in freshwater only.


30 Verification of colonies by incubation of BHI agar at 10 ± 0.5 °C for 48 ± 3 h is optional. As per the Errata to the 23rd Edition of Standard Methods for the Examination of Water and Wastewater “Growth on a BHI agar plate incubated at 10 ± 0.5 °C for 48 ± 3 h is further verification that the colony belongs to the genus Enterococcus.”


31 Method 1623.1 includes updated acceptance criteria for IPR, OPR, and MS/MSD and clarifications and revisions based on the use of Method 1623 for years and technical support questions.


32 9221 F.2-2014 allows for simultaneous detection of E. coli and thermotolerant fecal coliforms by adding inverted vials to EC-MUG; the inverted vials collect gas produced by thermotolerant fecal coliforms.


(b) Certain material is incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. All approved material may be inspected at EPA’s Water Docket, EPA West, 1301 Constitution Avenue NW, Room 3334, Washington, DC 20004, (Telephone: 202-566-2426). It is also available for inspection at National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.


(1) Environmental Monitoring and Support Laboratory, U.S. Environmental Protection Agency, Cincinnati OH (US EPA). Available at http://water.epa.gov/scitech/methods/cwa/index.cfm or from: National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161


(i) Microbiological Methods for Monitoring the Environment, Water, and Wastes. 1978. EPA/600/8-78/017, Pub. No. PB-290329/A.S.


(A) Part III Analytical Methodology, Section B Total Coliform Methods, page 108. Table IA, Note 3; Table IH, Note 3.


(B) Part III Analytical Methodology, Section B Total Coliform Methods, 2.6.2 Two-Step Enrichment Procedure, page 111. Table IA, Note 3; Table IH, Note 3.


(C) Part III Analytical Methodology, Section B Total Coliform Methods, 4 Most Probable Number (MPN) Method, page 114. Table IA, Note 3; Table IH, Note 3.


(D) Part III Analytical Methodology, Section C Fecal Coliform Methods, 2 Direct Membrane Filter (MF) Method, page 124. Table IA, Note 3; Table IH, Note 3.


(E) Part III, Analytical Methodology, Section C Fecal Coliform Methods, 5 Most Probable Number (MPN) Method, page 132. Table IA, Note 3; Table IH, Note 3.


(F) Part III Analytical Methodology, Section D Fecal Streptococci, 2 Membrane Filter (MF) Method, page 136. Table IA, Note 3; Table IH, Note 3.


(G) Part III Analytical Methodology, Section D Fecal Streptococci, 4 Most Probable Number Method, page 139. Table IA, Note 3; Table IH, Note 3.


(H) Part III Analytical Methodology, Section D Fecal Streptococci, 5 Pour Plate Method, page 143. Table IA, Note 3; Table IH, Note 3.


(ii) [Reserved]


(2) Environmental Monitoring and Support Laboratory, U.S. Environmental Protection Agency, Cincinnati OH (US EPA). Available at http://water.epa.gov/scitech/methods/cwa/index.cfm.


(i) Method 300.1 (including Errata Cover Sheet, April 27, 1999), Determination of Inorganic Ions in Drinking Water by Ion Chromatography, Revision 1.0, 1997. Table IB, Note 52.


(ii) Method 551, Determination of Chlorination Disinfection Byproducts and Chlorinated Solvents in Drinking Water by Liquid-Liquid Extraction and Gas Chromatography With Electron-Capture Detection. 1990. Table IF.


(3) National Exposure Risk Laboratory-Cincinnati, U.S. Environmental Protection Agency, Cincinnati OH (US EPA). Available from http://water.epa.gov/scitech/methods/cwa/index.cfm or from the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161. Telephone: 800-553-6847.


(i) Methods for the Determination of Inorganic Substances in Environmental Samples. August 1993. EPA/600/R-93/100, Pub. No. PB 94120821. Table IB, Note 52.


(A) Method 180.1, Determination of Turbidity by Nephelometry. Revision 2.0. Table IB, Note 52.


(B) Method 300.0, Determination of Inorganic Anions by Ion Chromatography. Revision 2.1. Table IB, Note 52.


(C) Method 335.4, Determination of Total Cyanide by Semi-Automated Colorimetry. Revision 1.0. Table IB, Notes 52 and 57.


(D) Method 350.1, Determination of Ammonium Nitrogen by Semi-Automated Colorimetry. Revision 2.0. Table IB, Notes 30 and 52.


(E) Method 351.2, Determination of Total Kjeldahl Nitrogen by Semi-Automated Colorimetry. Revision 2.0. Table IB, Note 52.


(F) Method 353.2, Determination of Nitrate-Nitrite Automated Colorimetry. Revision 2.0. Table IB, Note 52.


(G) Method 365.1, Determination of Phosphorus by Automated Colorimetry. Revision 2.0. Table IB, Note 52.


(H) Method 375.2, Determination of Sulfate by Automated Colorimetry. Revision 2.0. Table IB, Note 52.


(I) Method 410.4, Determination of Chemical Oxygen Demand by Semi-Automated Colorimetry. Revision 2.0. Table IB, Note 52.


(ii) Methods for the Determination of Metals in Environmental Samples, Supplement I. May 1994. EPA/600/R-94/111, Pub. No. PB 95125472. Table IB, Note 52.


(A) Method 200.7, Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry. Revision 4.4. Table IB, Note 52.


(B) Method 200.8, Determination of Trace Elements in Water and Wastes by Inductively Coupled Plasma Mass Spectrometry. Revision 5.3. Table IB, Note 52.


(C) Method 200.9, Determination of Trace Elements by Stabilized Temperature Graphite Furnace Atomic Absorption Spectrometry. Revision 2.2. Table IB, Note 52.


(D) Method 218.6, Determination of Dissolved Hexavalent Chromium in Drinking Water, Groundwater, and Industrial Wastewater Effluents by Ion Chromatography. Revision 3.3. Table IB, Note 52.


(E) Method 245.1, Determination of Mercury in Water by Cold Vapor Atomic Absorption Spectrometry. Revision 3.0. Table IB, Note 52.


(4) National Exposure Risk Laboratory-Cincinnati, U.S. Environmental Protection Agency, Cincinnati OH (US EPA). Available at http://water.epa.gov/scitech/methods/cwa/index.cfm.


(i) EPA Method 200.5, Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry. Revision 4.2, October 2003. EPA/600/R-06/115. Table IB, Note 68.


(ii) EPA Method 525.2, Determination of Organic Compounds in Drinking Water by Liquid-Solid Extraction and Capillary Column Gas Chromatography/Mass Spectrometry. Revision 2.0, 1995. Table ID, Note 10.


(5) Office of Research and Development, Cincinnati OH. U.S. Environmental Protection Agency, Cincinnati OH (US EPA). Available at http://water.epa.gov/scitech/methods/cwa/index.cfm or from ORD Publications, CERI, U.S. Environmental Protection Agency, Cincinnati OH 45268.


(i) Methods for Benzidine, Chlorinated Organic Compounds, Pentachlorophenol, and Pesticides in Water and Wastewater. 1978. Table IC, Note 3; Table ID, Note 3.


(ii) Methods for Chemical Analysis of Water and Wastes. March 1979. EPA-600/4-79-020. Table IB, Note 1.


(iii) Methods for Chemical Analysis of Water and Wastes. Revised March 1983. EPA-600/4-79-020. Table IB, Note 1.


(A) Method 120.1, Conductance, Specific Conductance, µmhos at 25 °C. Revision 1982. Table IB, Note 1.


(B) Method 130.1, Hardness, Total (mg/L as CaCO3), Colorimetric, Automated EDTA. Issued 1971. Table IB, Note 1.


(C) Method 150.2, pH, Continuous Monitoring (Electrometric). December 1982. Table IB, Note 1.


(D) Method 160.4, Residue, Volatile, Gravimetric, Ignition at 550 °C. Issued 1971. Table IB, Note 1.


(E) Method 206.5, Arsenic, Sample Digestion Prior to Total Arsenic Analysis by Silver Diethyldithiocarbamate or Hydride Procedures. Issued 1978. Table IB, Note 1.


(F) Method 231.2, Gold, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(G) Method 245.2, Mercury, Automated Cold Vapor Technique. Issued 1974. Table IB, Note 1.


(H) Method 252.2, Osmium, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(I) Method 253.2, Palladium, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(J) Method 255.2, Platinum, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(K) Method 265.2, Rhodium, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(L) Method 279.2, Thallium, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(M) Method 283.2, Titanium, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(N) Method 289.2, Zinc, Atomic Absorption, Furnace Technique. Issued 1978. Table IB, Note 1.


(O) Method 310.2, Alkalinity, Colorimetric, Automated, Methyl Orange. Revision 1974. Table IB, Note 1.


(P) Method 351.1, Nitrogen, Kjeldahl, Total, Colorimetric, Automated Phenate. Revision 1978. Table IB, Note 1.


(Q) Method 352.1, Nitrogen, Nitrate, Colorimetric, Brucine. Issued 1971. Table IB, Note 1.


(R) Method 365.3, Phosphorus, All Forms, Colorimetric, Ascorbic Acid, Two Reagent. Issued 1978. Table IB, Note 1.


(S) Method 365.4, Phosphorus, Total, Colorimetric, Automated, Block Digestor AA II. Issued 1974. Table IB, Note 1.


(T) Method 410.3, Chemical Oxygen Demand, Titrimetric, High Level for Saline Waters. Revision 1978. Table IB, Note 1.


(U) Method 420.1, Phenolics, Total Recoverable, Spectrophotometric, Manual 4-AAP With Distillation. Revision 1978. Table IB, Note 1.


(iv) Prescribed Procedures for Measurement of Radioactivity in Drinking Water. 1980. EPA-600/4-80-032. Table IE.


(A) Method 900.0, Gross Alpha and Gross Beta Radioactivity. Table IE.


(B) Method 903.0, Alpha-Emitting iRadio Isotopes. Table IE.


(C) Method 903.1, Radium-226, Radon Emanation Technique. Table IE.


(D) Appendix B, Error and Statistical Calculations. Table IE.


(6) Office of Science and Technology, U.S. Environmental Protection Agency, Washington DC (US EPA). Available at http://water.epa.gov/scitech/methods/cwa/index.cfm.


(i) Method 1625C, Semivolatile Organic Compounds by Isotope Dilution GCMS. 1989. Table IF.


(ii) [Reserved]


(7) Office of Water, U.S. Environmental Protection Agency, Washington DC (US EPA). Available at http://water.epa.gov/scitech/methods/cwa/index.cfm or from National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161.


(i) Method 1631, Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry. Revision E, August 2002. EPA-821-R-02-019, Pub. No. PB2002-108220. Table IB, Note 43.


(ii) Kelada-01, Kelada Automated Test Methods for Total Cyanide, Acid Dissociable Cyanide, and Thiocyanate. Revision 1.2, August 2001. EPA 821-B-01-009, Pub. No. PB 2001-108275. Table IB, Note 55.


(iii) In the compendium Analytical Methods for the Determination of Pollutants in Pharmaceutical Manufacturing Industry Wastewaters. July 1998. EPA 821-B-98-016, Pub. No. PB95201679. Table IF, Note 1.


(A) EPA Method 1666, Volatile Organic Compounds Specific to the Pharmaceutical Industry by Isotope Dilution GC/MS. Table IF, Note 1.


(B) EPA Method 1667, Formaldehyde, Isobutyraldehyde, and Furfural by Derivatization Followed by High Performance Liquid Chromatography. Table IF.


(C) Method 1671, Volatile Organic Compounds Specific to the Pharmaceutical Manufacturing Industry by GC/FID. Table IF.


(iv) Methods For The Determination of Nonconventional Pesticides In Municipal and Industrial Wastewater, Volume I. Revision I, August 1993. EPA 821-R-93-010A, Pub. No. PB 94121654. Tables ID, IG.


(A) Method 608.1, Organochlorine Pesticides. Table ID, Note 10; Table IG, Note 3.


(B) Method 608.2, Certain Organochlorine Pesticides. Table ID, Note 10; Table IG, Note 3.


(C) Method 614, Organophosphorus Pesticides. Table ID, Note 10; Table IG, Note 3.


(D) Method 614.1, Organophosphorus Pesticides. Table ID, Note 10; Table IG, Note 3.


(E) Method 615, Chlorinated Herbicides. Table ID, Note 10; Table IG, Note 3.


(F) Method 617, Organohalide Pesticides and PCBs. Table ID, Note 10; Table IG, Note 3.


(G) Method 619, Triazine Pesticides. Table ID, Note 10; Table IG, Note 3.


(H) Method 622, Organophosphorus Pesticides. Table ID, Note 10; Table IG, Note 3.


(I) Method 622.1, Thiophosphate Pesticides. Table ID, Note 10; Table IG, Note 3.


(J) Method 627, Dinitroaniline Pesticides. Table ID, Note 10; Table IG, Notes 1 and 3.


(K) Method 629, Cyanazine. Table IG, Note 3.


(L) Method 630, Dithiocarbamate Pesticides. Table IG, Note 3.


(M) Method 630.1, Dithiocarbamate Pesticides. Table IG, Note 3.


(N) Method 631, Benomyl and Carbendazim. Table IG, Note 3.


(O) Method 632, Carbamate and Urea Pesticides. Table ID, Note 10; Table IG, Note 3.


(P) Method 632.1, Carbamate and Amide Pesticides. Table IG, Note 3.


(Q) Method 633, Organonitrogen Pesticides. Table IG, Note 3.


(R) Method 633.1, Neutral Nitrogen-Containing Pesticides. Table IG, Note 3.


(S) Method 637, MBTS and TCMTB. Table IG, Note 3.


(T) Method 644, Picloram. Table IG, Note 3.


(U) Method 645, Certain Amine Pesticides and Lethane. Table IG, Note 3.


(V) Method 1656, Organohalide Pesticides. Table ID, Note 10; Table IG, Notes 1 and 3.


(W) Method 1657, Organophosphorus Pesticides. Table ID, Note 10; Table IG, Note 3.


(X) Method 1658, Phenoxy-Acid Herbicides. Table IG, Note 3.


(Y) Method 1659, Dazomet. Table IG, Note 3.


(Z) Method 1660, Pyrethrins and Pyrethroids. Table IG, Note 3.


(AA) Method 1661, Bromoxynil. Table IG, Note 3.


(BB) Ind-01. Methods EV-024 and EV-025, Analytical Procedures for Determining Total Tin and Triorganotin in Wastewater. Table IG, Note 3.


(v) Methods For The Determination of Nonconventional Pesticides In Municipal and Industrial Wastewater, Volume II. August 1993. EPA 821-R-93-010B, Pub. No. PB 94166311. Table IG.


(A) Method 200.9, Determination of Trace Elements by Stabilized Temperature Graphite Furnace Atomic Absorption Spectrometry. Table IG, Note 3.


(B) Method 505, Analysis of Organohalide Pesticides and Commercial Polychlorinated Biphenyl (PCB) Products in Water by Microextraction and Gas Chromatography. Table ID, Note 10; Table IG, Note 3.


(C) Method 507, The Determination of Nitrogen- and Phosphorus-Containing Pesticides in Water by Gas Chromatography with a Nitrogen-Phosphorus Detector. Table ID, Note 10; Table IG, Note 3.


(D) Method 508, Determination of Chlorinated Pesticides in Water by Gas Chromatography with an Electron Capture Detector. Table ID, Note 10; Table IG, Note 3.


(E) Method 515.1, Determination of Chlorinated Acids in Water by Gas Chromatography with an Electron Capture Detector. Table IG, Notes 2 and 3.


(F) Method 515.2, Determination of Chlorinated Acids in Water Using Liquid-Solid Extraction and Gas Chromatography with an Electron Capture Detector. Table IG, Notes 2 and 3.


(G) Method 525.1, Determination of Organic Compounds in Drinking Water by Liquids-Solid Extraction and Capillary Column Gas Chromatography/Mass Spectrometry. Table ID, Note 10; Table IG, Note 3.


(H) Method 531.1, Measurement of N-Methylcarbamoyloximes and N-Methylcarbamates in Water by Direct Aqueous Injection HPLC with Post-Column Derivatization. Table ID, Note 10; Table IG, Note 3.


(I) Method 547, Determination of Glyphosate in Drinking Water by Direct-Aqueous-Injection HPLC, Post-Column Derivatization, and Fluorescence Detection. Table IG, Note 3.


(J) Method 548, Determination of Endothall in Drinking Water by Aqueous Derivatization, Liquid-Solid Extraction, and Gas Chromatography with Electron-Capture Detector. Table IG, Note 3.


(K) Method 548.1, Determination of Endothall in Drinking Water by Ion-Exchange Extraction, Acidic Methanol Methylation and Gas Chromatography/Mass Spectrometry. Table IG, Note 3.


(L) Method 553, Determination of Benzidines and Nitrogen-Containing Pesticides in Water by Liquid-Liquid Extraction or Liquid-Solid Extraction and Reverse Phase High Performance Liquid Chromatography/Particle Beam/Mass Spectrometry Table ID, Note 10; Table IG, Note 3.


(M) Method 555, Determination of Chlorinated Acids in Water by High Performance Liquid Chromatography With a Photodiode Array Ultraviolet Detector. Table IG, Note 3.


(vi) In the compendium Methods for the Determination of Organic Compounds in Drinking Water. Revised July 1991, December 1998. EPA-600/4-88-039, Pub. No. PB92-207703. Table IF.


(A) EPA Method 502.2, Volatile Organic Compounds in Water by Purge and Trap Capillary Column Gas Chromatography with Photoionization and Electrolytic Conductivity Detectors in Series. Table IF.


(B) [Reserved]


(vii) In the compendium Methods for the Determination of Organic Compounds in Drinking Water-Supplement II. August 1992. EPA-600/R-92-129, Pub. No. PB92-207703. Table IF.


(A) EPA Method 524.2, Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry. Table IF.


(B) [Reserved]


(viii) Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. October 2002. EPA 821-R-02-012, Pub. No. PB2002-108488. Table IA, Note 26.


(ix) Short-Term Methods for Measuring the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, Fourth Edition. October 2002. EPA 821-R-02-013, Pub. No. PB2002-108489. Table IA, Note 27.


(x) Short-Term Methods for Measuring the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Third Edition. October 2002. EPA 821-R-02-014, Pub. No. PB2002-108490. Table IA, Note 28.


(8) Office of Water, U.S. Environmental Protection Agency, Washington, DC (U.S. EPA). Available at https://www.epa.gov/cwa-methods.


(i) Method 245.7, Mercury in Water by Cold Vapor Atomic Fluorescence Spectrometry. Revision 2.0, February 2005. EPA-821-R-05-001. Table IB, Note 17.


(ii) Method 1103.1: Escherichia coli (E. coli) in Water by Membrane Filtration Using membrane-Thermotolerant Escherichia coli Agar (mTEC). March 2010. EPA-621-R-10-002. Table IH, Note 19.


(iii) Method 1106.1: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus-Esculin Iron Agar (mE-EIA). December 2009. EPA-621-R-09-015. Table IH, Note 23.


(iv) Method 1600: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus Indoxyl-β-D-Glucoside Agar (mEI). September 2014. EPA-821-R-14-011. Table IA, Note 25; Table IH, Note 24.


(v) Method 1603: Escherichia coli (E. coli) in Water by Membrane Filtration Using Modified membrane-Thermotolerant Escherichia coli Agar (Modified mTEC). September 2014. EPA-821-R-14-010. Table IA, Note 22; Table IH, Note 20.


(vi) Method 1604: Total Coliforms and Escherichia coli (E. coli) in Water by Membrane Filtration Using a Simultaneous Detection Technique (MI Medium). September 2002. EPA-821-R-02-024. Table IH, Note 21.


(vii) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA. December 2005. EPA-821-R-05-001. Table IH, Note 25.


(viii) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA. December 2005. EPA-821-R-05-002. Table IH, Note 26.


(ix) Method 1623.1: Cryptosporidium and Giardia in Water by Filtration/IMS/FA. EPA 816-R-12-001. January 2012. U.S. EPA, Table IH, Note 25.


(x) Method 1627, Kinetic Test Method for the Prediction of Mine Drainage Quality. December 2011. EPA-821-R-09-002. Table IB, Note 69.


(xi) Method 1664, n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Nonpolar Material) by Extraction and Gravimetry. Revision A, February 1999. EPA-821-R-98-002. Table IB, Notes 38 and 42.


(xii) Method 1664, n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Nonpolar Material) by Extraction and Gravimetry, Revision B, February 2010. EPA-821-R-10-001. Table IB, Notes 38 and 42.


(xiii) Method 1669, Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria Levels. July 1996. Table IB, Note 43.


(xiv) Method 1680: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation using Lauryl Tryptose Broth (LTB) and EC Medium. September 2014. EPA-821-R-14-009.Table IA, Note 15.


(xv) Method 1681: Fecal Coliforms in Sewage Sludge (Biosolids) by Multiple-Tube Fermentation using A-1 Medium. July 2006. EPA 821-R-06-013. Table IA, Note 20.


(xvi) Method 1682: Salmonella in Sewage Sludge (Biosolids) by Modified Semisolid Rappaport-Vassiliadis (MSRV) Medium. September 2014. EPA 821-R-14-012. Table IA, Note 23.


(9) American National Standards Institute, 1430 Broadway, New York NY 10018.


(i) ANSI. American National Standard on Photographic Processing Effluents. April 2, 1975. Table IB, Note 9.


(ii) [Reserved]


(10) American Public Health Association, 1015 15th Street NW., Washington, DC 20005. Standard Methods Online is available through the Standard Methods Web site (http://www.standardmethods.org).


(i) Standard Methods for the Examination of Water and Wastewater. 14th Edition, 1975. Table IB, Notes 17 and 27.


(ii) Standard Methods for the Examination of Water and Wastewater. 15th Edition, 1980, Table IB, Note 30; Table ID.


(iii) Selected Analytical Methods Approved and Cited by the United States Environmental Protection Agency, Supplement to the 15th Edition of Standard Methods for the Examination of Water and Wastewater. 1981. Table IC, Note 6; Table ID, Note 6.


(iv) Standard Methods for the Examination of Water and Wastewater. 18th Edition, 1992. Tables IA, IB, IC, ID, IE, and IH.


(v) Standard Methods for the Examination of Water and Wastewater. 19th Edition, 1995. Tables IA, IB, IC, ID, IE, and IH.


(vi) Standard Methods for the Examination of Water and Wastewater. 20th Edition, 1998. Tables IA, IB, IC, ID, IE, and IH.


(vii) Standard Methods for the Examination of Water and Wastewater. 21st Edition, 2005. Table IB, Notes 17 and 27.


(viii) 2120, Color. 2011. Table IB.


(ix) 2130, Turbidity. 2011. Table IB.


(x) 2310, Acidity. 2011. Table IB.


(xi) 2320, Alkalinity. 2011. Table IB.


(xii) 2340, Hardness. 2011. Table IB.


(xiii) 2510, Conductivity. 2011. Table IB.


(xiv) 2540, solids. 2015. Table IB.


(xv) 2550, Temperature. 2010. Table IB.


(xvi) 3111, Metals by Flame Atomic Absorption Spectrometry. 2011. Table IB.


(xvii) 3112, Metals by Cold-Vapor Atomic Absorption Spectrometry. 2011. Table IB.


(xviii) 3113, Metals by Electrothermal Atomic Absorption Spectrometry. 2010. Table IB.


(xix) 3114, Arsenic and Selenium by Hydride Generation/Atomic Absorption Spectrometry. 2011. Table IB.


(xx) 3120, Metals by Plasma Emission Spectroscopy. 2011. Table IB.


(xxi) 3125, Metals by Inductively Coupled Plasma-Mass Spectrometry. 2011. Table IB.


(xxii) 3500-Al, Aluminum. 2011. Table IB.


(xxiii) 3500-As, Arsenic. 2011. Table IB.


(xxiv) 3500-Ca, Calcium. 2011. Table IB.


(xxv) 3500-Cr, Chromium. 2011. Table IB.


(xxvi) 3500-Cu, Copper. 2011. Table IB.


(xxvii) 3500-Fe, Iron. 2011. Table IB.


(xxviii) 3500-Pb, Lead. 2011. Table IB.


(xxix) 3500-Mn, Manganese. 2011. Table IB.


(xxx) 3500-K, Potassium. 2011. Table IB.


(xxxi) 3500-Na, Sodium. 2011. Table IB.


(xxxii) 3500-V, Vanadium. 2011. Table IB.


(xxxiii) 3500-Zn, Zinc. 2011. Table IB.


(xxxiv) 4110, Determination of Anions by Ion Chromatography. 2011. Table IB.


(xxxv) 4140, Inorganic Anions by Capillary Ion Electrophoresis. 2011. Table IB.


(xxxvi) 4500-B, Boron. 2011. Table IB.


(xxxvii) 4500-Cl−, Chloride. 2011. Table IB.


(xxxviii) 4500-Cl, Chlorine (Residual). 2011. Table IB.


(xxxix) 4500-CN−, Cyanide. 2016. Table IB.


(xl) 4500-F−, Fluoride. 2011. Table IB.


(xli) 4500-H+, pH Value. 2011. Table IB.


(xlii) 4500-NH3, Nitrogen (Ammonia). 2011. Table IB.


(xliii) 4500-NO2−, Nitrogen (Nitrite). 2011. Table IB.


(xliv) 4500-NO3-, Nitrogen (Nitrate). 2016. Table IB.


(xlv) 4500-Norg, Nitrogen (Organic). 2011. Table IB.


(xlvi) 4500-O, Oxygen (Dissolved). 2016. Table IB.


(xlvii) 4500-P, Phosphorus. 2011. Table IB.


(xlviii) 4500-SiO2, Silica. 2011. Table IB.


(xlix) 4500-S2−, Sulfide. 2011. Table IB.


(l) 4500-SO32−, Sulfite. 2011. Table IB.


(li) 4500-SO42−, Sulfate. 2011. Table IB.


(lii) 5210, Biochemical Oxygen Demand (BOD). 2016. Table IB.


(liii) 5220, Chemical Oxygen Demand (COD). 2011. Table IB.


(liv) 5310, Total Organic Carbon (TOC). 2014. Table IB.


(lv) 5520, Oil and Grease. 2011. Table IB.


(lvi) 5530, Phenols. 2010. Table IB.


(lvii) 5540, Surfactants. 2011. Table IB.


(lviii) 6200, Volatile Organic Compounds. 2011. Table IC.


(lix) 6410, Extractable Base/Neutrals and Acids. 2000. Tables IC, ID.


(lx) 6420, Phenols. 2000. Table IC.


(lxi) 6440, Polynuclear Aromatic Hydrocarbons. 2005. Table IC.


(lxii) 6630, Organochlorine Pesticides. 2007. Table ID.


(lxiii) 6640, Acidic Herbicide Compounds. 2006. Table ID.


(lxiv) 7110, Gross Alpha and Gross Beta Radioactivity (Total, Suspended, and Dissolved). 2000. Table IE.


(lxv) 7500, Radium. 2001. Table IE.


(lxvi) 9213, Recreational Waters. 2007. Table IH.


(lxvii) 9221 Multiple-Tube Fermentation Technique for Members of the Coliform Group. 2014. Table IA, Notes 12 and 14; Table IH, Notes 10 and 12.


(lxviii) 9222, Membrane Filter Technique for Members of the Coliform Group. 2015. Table IA; Table IH, Note 17.


(lxix) 9223 Enzyme Substrate Coliform Test. 2016. Table IA; Table IH.


(lxx) 9230 Fecal Enterococcus/Streptococcus Groups. 2013. Table IA; Table IH.


(11) The Analyst, The Royal Society of Chemistry, RSC Publishing, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 0WF, United Kingdom. (Also available from most public libraries.)


(i) Spectrophotometric Determination of Ammonia: A Study of a Modified Berthelot Reaction Using Salicylate and Dichloroisocyanurate. Krom, M.D. 105:305-316, April 1980. Table IB, Note 60.


(ii) [Reserved]


(12) Analytical Chemistry, ACS Publications, 1155 Sixteenth St. NW., Washington DC 20036. (Also available from most public libraries.)


(i) Spectrophotometric and Kinetics Investigation of the Berthelot Reaction for the Determination of Ammonia. Patton, C.J. and S.R. Crouch. 49(3):464-469, March 1977. Table IB, Note 60.


(ii) [Reserved]


(13) AOAC International, 481 North Frederick Avenue, Suite 500, Gaithersburg, MD 20877-2417.


(i) Official Methods of Analysis of AOAC International. 16th Edition, 4th Revision, 1998.


(A) 920.203, Manganese in Water, Persulfate Method. Table IB, Note 3.


(B) 925.54, Sulfate in Water, Gravimetric Method. Table IB, Note 3.


(C) 973.40, Specific Conductance of Water. Table IB, Note 3.


(D) 973.41, pH of Water. Table IB, Note 3.


(E) 973.43, Alkalinity of Water, Titrimetric Method. Table IB, Note 3.


(F) 973.44, Biochemical Oxygen Demand (BOD) of Water, Incubation Method. Table IB, Note 3.


(G) 973.45, Oxygen (Dissolved) in Water, Titrimetric Methods. Table IB, Note 3.


(H) 973.46, Chemical Oxygen Demand (COD) of Water, Titrimetric Methods. Table IB, Note 3.


(I) 973.47, Organic Carbon in Water, Infrared Analyzer Method. Table IB, Note 3.


(J) 973.48, Nitrogen (Total) in Water, Kjeldahl Method. Table IB, Note 3.


(K) 973.49, Nitrogen (Ammonia) in Water, Colorimetric Method. Table IB, Note 3.


(L) 973.50, Nitrogen (Nitrate) in Water, Brucine Colorimetric Method. Table IB, Note 3.


(M) 973.51, Chloride in Water, Mercuric Nitrate Method. Table IB, Note 3.


(N) 973.52, Hardness of Water. Table IB, Note 3.


(O) 973.53, Potassium in Water, Atomic Absorption Spectrophotometric Method. Table IB, Note 3.


(P) 973.54, Sodium in Water, Atomic Absorption Spectrophotometric Method. Table IB, Note 3.


(Q) 973.55, Phosphorus in Water, Photometric Method. Table IB, Note 3.


(R) 973.56, Phosphorus in Water, Automated Method. Table IB, Note 3.


(S) 974.27, Cadmium, Chromium, Copper, Iron, Lead, Magnesium, Manganese, Silver, Zinc in Water, Atomic Absorption Spectrophotometric Method. Table IB, Note 3.


(T) 977.22, Mercury in Water, Flameless Atomic Absorption Spectrophotometric Method. Table IB, Note 3.


(U) 991.15. Total Coliforms and Escherichia coli in Water Defined Substrate Technology (Colilert) Method. Table IA, Note 10; Table IH, Note 10.


(V) 993.14, Trace Elements in Waters and Wastewaters, Inductively Coupled Plasma-Mass Spectrometric Method. Table IB, Note 3.


(W) 993.23, Dissolved Hexavalent Chromium in Drinking Water, Ground Water, and Industrial Wastewater Effluents, Ion Chromatographic Method. Table IB, Note 3.


(X) 993.30, Inorganic Anions in Water, Ion Chromatographic Method. Table IB, Note 3.


(ii) [Reserved]


(14) Applied and Environmental Microbiology, American Society for Microbiology, 1752 N Street NW., Washington DC 20036. (Also available from most public libraries.)


(i) New Medium for the Simultaneous Detection of Total Coliforms and Escherichia coli in Water. Brenner, K.P., C.C. Rankin, Y.R. Roybal, G.N. Stelma, Jr., P.V. Scarpino, and A.P. Dufour. 59:3534-3544, November 1993. Table IH, Note 21.


(ii) [Reserved]


(15) ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, or online at http://www.astm.org.


(i) Annual Book of ASTM Standards, Water, and Environmental Technology, Section 11, Volumes 11.01 and 11.02. 1994. Tables IA, IB, IC, ID, IE, and IH.


(ii) Annual Book of ASTM Standards, Water, and Environmental Technology, Section 11, Volumes 11.01 and 11.02. 1996. Tables IA, IB, IC, ID, IE, and IH.


(iii) Annual Book of ASTM Standards, Water, and Environmental Technology, Section 11, Volumes 11.01 and 11.02. 1999. Tables IA, IB, IC, ID, IE, and IH.


(iv) Annual Book of ASTM Standards, Water, and Environmental Technology, Section 11, Volumes 11.01 and 11.02. 2000. Tables IA, IB, IC, ID, IE, and IH.


(v) ASTM D511-14, Standard Test Methods for Calcium and Magnesium in Water. November 2014. Table IB.


(vi) ASTM D512-12, Standard Test Methods for Chloride Ion in Water. July 2012. Table IB.


(vii) ASTM D515-88, Test Methods for Phosphorus in Water, March 1989. Table IB.


(viii) ASTM D516-16, Standard Test Method for Sulfate Ion in Water, June 2016. Table IB.


(ix) ASTM D858-17, Standard Test Methods for Manganese in Water. June 2017. Table IB.


(x) ASTM D859-16, Standard Test Method for Silica in Water. June 2016. Table IB.


(xi) ASTM D888-12, Standard Test Methods for Dissolved Oxygen in Water. March 2012. Table IB.


(xii) ASTM D1067-16, Standard Test Methods for Acidity or Alkalinity of Water. June 2016. Table IB.


(xiii) ASTM D1068-15, Standard Test Methods for Iron in Water. October 2015. Table IB.


(xiv) ASTM D1125-95 (Reapproved 1999), Standard Test Methods for Electrical Conductivity and Resistivity of Water. December 1995. Table IB.


(xv) ASTM D1126-17, Standard Test Method for Hardness in Water. December 2017. Table IB.


(xvi) ASTM D1179-16, Standard Test Methods for Fluoride Ion in Water. June 2016. Table IB.


(xvii) ASTM D1246-16, Standard Test Method for Bromide Ion in Water. June 2016. Table IB.


(xviii) ASTM D1252-06 (Reapproved 2012), Standard Test Methods for Chemical Oxygen Demand (Dichromate Oxygen Demand) of Water. June 2012. Table IB.


(xix) ASTM D1253-14, Standard Test Method for Residual Chlorine in Water. February 2014. Table IB.


(xx) ASTM D1293-99, Standard Test Methods for pH of Water. March 2000. Table IB.


(xxi) ASTM D1426-15, Standard Test Methods for Ammonia Nitrogen in Water. April 2015. Table IB.


(xxii) ASTM D1687-17, Standard Test Methods for Chromium in Water. July 2017. Table IB.


(xxiii) ASTM D1688-17, Standard Test Methods for Copper in Water. July 2017. Table IB.


(xxiv) ASTM D1691-17, Standard Test Methods for Zinc in Water. June 2017. Table IB.


(xxv) ASTM D1783-01 (Reapproved 2012), Standard Test Methods for Phenolic Compounds in Water. August 2012. Table IB.


(xxvi) ASTM D1886-14, Standard Test Methods for Nickel in Water. November 2014. Table IB.


(xxvii) ASTM D1889-00, Standard Test Method for Turbidity of Water. October 2000. Table IB.


(xxviii) ASTM D1890-96, Standard Test Method for Beta Particle Radioactivity of Water. April 1996. Table IE.


(xxix) ASTM D1943-96, Standard Test Method for Alpha Particle Radioactivity of Water. April 1996. Table IE.


(xxx) ASTM D1976-12, Standard Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission Spectroscopy. March 2012. Table IB.


(xxxi) ASTM D2036-09 (Reapproved 2015), Standard Test Methods for Cyanides in Water. July 2015. Table IB.


(xxxii) ASTM D2330-02, Standard Test Method for Methylene Blue Active Substances. August 2002. Table IB.


(xxxiii) ASTM D2460-97, Standard Test Method for Alpha-Particle-Emitting Isotopes of Radium in Water. October 1997. Table IE.


(xxxiv) ASTM D2972-15, Standard Tests Method for Arsenic in Water. March 2015. Table IB.


(xxxv) ASTM D3223-17, Standard Test Method for Total Mercury in Water. June 2017. Table IB.


(xxxvi) ASTM D3371-95, Standard Test Method for Nitriles in Aqueous Solution by Gas-Liquid Chromatography, February 1996. Table IF.


(xxxvii) ASTM D3373-17, Standard Test Method for Vanadium in Water. June 2017. Table IB.


(xxxviii) ASTM D3454-97, Standard Test Method for Radium-226 in Water. February 1998. Table IE.


(xxxix) ASTM D3557-17, Standard Test Method for Cadmium in Water. June 2017. Table IB.


(xl) ASTM D3558-15, Standard Test Method for Cobalt in Water. March 2015. Table IB.


(xli) ASTM D3559-15, Standard Test Methods for Lead in Water. October 2015. Table IB.


(xlii) ASTM D3590-17, Standard Test Methods for Total Kjeldahl Nitrogen in Water. June 2017. Table IB.


(xliii) ASTM D3645-15, Standard Test Methods for Beryllium in Water. March 2015. Table IB.


(xliv) ASTM D3695-95, Standard Test Method for Volatile Alcohols in Water by Direct Aqueous-Injection Gas Chromatography. April 1995. Table IF.


(xlv) ASTM D3859-15, Standard Test Methods for Selenium in Water. April 2015. Table IB.


(xlvi) ASTM D3867-16, Standard Test Method for Nitrite-Nitrate in Water. June 2016. Table IB.


(xlvii) ASTM D4190-15, Standard Test Method for Elements in Water by Direct- Current Plasma Atomic Emission Spectroscopy. March 2015. Table IB.


(xlviii) ASTM D4282-15, Standard Test Method for Determination of Free Cyanide in Water and Wastewater by Microdiffusion. July 2015. Table IB.


(xlix) ASTM D4327-17, Standard Test Method for Anions in Water by Suppressed Ion Chromatography. December 2017. Table IB.


(l) ASTM D4382-18, Standard Test Method for Barium in Water, Atomic Absorption Spectrophotometry, Graphite Furnace. May 2018. Table IB.


(li) ASTM D4657-92 (Reapproved 1998), Standard Test Method for Polynuclear Aromatic Hydrocarbons in Water. January 1993. Table IC.


(lii) ASTM D4658-15, Standard Test Method for Sulfide Ion in Water. April 2015. Table IB.


(liii) ASTM D4763-88 (Reapproved 2001), Standard Practice for Identification of Chemicals in Water by Fluorescence Spectroscopy. September 1988. Table IF.


(liv) ASTM D4839-03 (Reapproved 2017), Standard Test Method for Total Carbon and Organic Carbon in Water by Ultraviolet, or Persulfate Oxidation, or Both, and Infrared Detection. December 2017. Table IB.


(lv) ASTM D5257-17, Standard Test Method for Dissolved Hexavalent Chromium in Water by Ion Chromatography. December 2017. Table IB.


(lvi) ASTM D5259-92, Standard Test Method for Isolation and Enumeration of Enterococci from Water by the Membrane Filter Procedure. October 1992. Table IH, Note 9.


(lvii) ASTM D5392-93, Standard Test Method for Isolation and Enumeration of Escherichia coli in Water by the Two-Step Membrane Filter Procedure. September 1993. Table IH, Note 9.


(lviii) ASTM D5673-16, Standard Test Method for Elements in Water by Inductively Coupled Plasma—Mass Spectrometry. February 2016. Table IB.


(lix) ASTM D5(19)907-13, Standard Test Method for Filterable Matter (Total Dissolved Solids) and Nonfilterable Matter (Total Suspended Solids) in Water. July 2013. Table IB.


(lx) ASTM D6503-99, Standard Test Method for Enterococci in Water Using Enterolert. April 2000. Table IA Note 9, Table IH, Note 9.


(lxi) ASTM. D6508-15, Standard Test Method for Determination of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate Electrolyte. October 2015. Table IB, Note 54.


(lxii) ASTM. D6888-16, Standard Test Method for Available Cyanide with Ligand Displacement and Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric Detection. June 2016. Table IB, Note 59.


(lxiii) ASTM. D6919-17, Standard Test Method for Determination of Dissolved Alkali and Alkaline Earth Cations and Ammonium in Water and Wastewater by Ion Chromatography. June 2017. Table IB.


(lxiv) ASTM. D7065-17, Standard Test Method for Determination of Nonylphenol, Bisphenol A, p-tert-Octylphenol, Nonylphenol Monoethoxylate and Nonylphenol Diethoxylate in Environmental Waters by Gas Chromatography Mass Spectrometry. January 2018. Table IC.


(lxv) ASTM. D7237-15a, Standard Test Method for Free Cyanide with Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric Detection. June 2015. Table IB.


(lxvi) ASTM. D7284-13 (Reapproved 2017), Standard Test Method for Total Cyanide in Water by Micro Distillation followed by Flow Injection Analysis with Gas Diffusion Separation and Amperometric Detection. July 2017. Table IB.


(lxvii) ASTM. D7365-09a, Standard Practice for Sampling, Preservation, and Mitigating Interferences in Water Samples for Analysis of Cyanide. October 2009. Table II, Notes 5 and 6.


(lxviii) ASTM. D7511-12 (Reapproved 2017), Standard Test Method for Total Cyanide by Segmented Flow Injection Analysis, In-Line Ultraviolet Digestion and Amperometric Detection. July 2017. Table IB.


(lxix) ASTM. D7573-09 (Reapproved 2017), Standard Test Method for Total Carbon and Organic Carbon in Water by High Temperature Catalytic Combustion and Infrared Detection, February 2017. Table IB.


(lxx) ASTM D7781-14 Standard Test Method for Nitrate-Nitrite in Water by Nitrate Reductase, May 2014. Table IB.


(16) Bran & Luebbe Analyzing Technologies, Inc., Elmsford NY 10523.


(i) Industrial Method Number 378-75WA, Hydrogen Ion (pH) Automated Electrode Method, Bran & Luebbe (Technicon) Auto Analyzer II. October 1976. Table IB, Note 21.


(ii) [Reserved]


(17) CEM Corporation, P.O. Box 200, Matthews NC 28106-0200.


(i) Closed Vessel Microwave Digestion of Wastewater Samples for Determination of Metals. April 16, 1992. Table IB, Note 36.


(ii) [Reserved]


(18) Craig R. Chinchilla, 900 Jorie Blvd., Suite 35, Oak Brook IL 60523. Telephone: 630-645-0600.


(i) Nitrate by Discrete Analysis Easy (1-Reagent) Nitrate Method, (Colorimetric, Automated, 1 Reagent). Revision 1, November 12, 2011. Table IB, Note 62.


(ii) [Reserved]


(19) FIAlab Instruments, Inc., 2151 N. Northlake Way, Seattle, WA 98103. Telephone: 425-376-0450.


(i) Method 100, Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Fluorescence Detector Analysis, April 4, 2018. Table IB, Note 82.


(ii) [Reserved]


(20) Hach Company, P.O. Box 389, Loveland CO 80537.


(i) Method 8000, Chemical Oxygen Demand. Hach Handbook of Water Analysis. 1979. Table IB, Note 14.


(ii) Method 8008, 1,10-Phenanthroline Method using FerroVer Iron Reagent for Water. 1980. Table IB, Note 22.


(iii) Method 8009, Zincon Method for Zinc. Hach Handbook for Water Analysis. 1979. Table IB, Note 33.


(iv) Method 8034, Periodate Oxidation Method for Manganese. Hach Handbook for Water Analysis. 1979. Table IB, Note 23.


(v) Method 8506, Bicinchoninate Method for Copper. Hach Handbook of Water Analysis. 1979. Table IB, Note 19.


(vi) Method 8507, Nitrogen, Nitrite—Low Range, Diazotization Method for Water and Wastewater. 1979. Table IB, Note 25.


(vii) Method 10206, Hach Company TNTplus 835/836 Nitrate Method 10206, Spectrophotometric Measurement of Nitrate in Water and Wastewater. Revision 2.1, January 10, 2013. Table IB, Note 75.


(viii) Method 10242, Hach Company TNTplus 880 Total Kjeldahl Nitrogen Method 10242, Simplified Spectrophotometric Measurement of Total Kjeldahl Nitrogen in Water and Wastewater. Revision 1.1, January 10, 2013. Table IB, Note 76.


(ix) Hach Method 10360, Luminescence Measurement of Dissolved Oxygen in Water and Wastewater and for Use in the Determination of BOD5 and cBOD5. Revision 1.2, October 2011. Table IB, Note 63.


(x) m-ColiBlue24® Method, for total Coliforms and E. coli. Revision 2, 1999. Table IA, Note 18; Table IH, Note 17.


(21) IDEXX Laboratories Inc., One Idexx Drive, Westbrook ME 04092.


(i) Colilert. 2013. Table IA, Notes 17 and 18; Table IH, Notes 14, 15 and 16.


(ii) Colilert-18. 2013. Table IA, Notes 17 and 18; Table IH, Notes 14, 15 and 16.


(iii) Enterolert. 2013. Table IA, Note 24; Table IH, Note 12.


(iv) Quanti-Tray Insert and Most Probable Number (MPN) Table. 2013. Table IA, Note 18; Table IH, Notes 14 and 16.


(22) In-Situ Incorporated, 221 E. Lincoln Ave., Ft. Collins CO 80524. Telephone: 970-498-1500.


(i) In-Situ Inc. Method 1002-8-2009, Dissolved Oxygen Measurement by Optical Probe. 2009. Table IB, Note 64.


(ii) In-Situ Inc. Method 1003-8-2009, Biochemical Oxygen Demand (BOD) Measurement by Optical Probe. 2009. Table IB, Note 10.


(iii) In-Situ Inc. Method 1004-8-2009, Carbonaceous Biochemical Oxygen Demand (CBOD) Measurement by Optical Probe. 2009. Table IB, Note 35.


(23) Journal of Chromatography, Elsevier/North-Holland, Inc., Journal Information Centre, 52 Vanderbilt Avenue, New York NY 10164. (Also available from most public libraries.


(i) Direct Determination of Elemental Phosphorus by Gas-Liquid Chromatography. Addison, R.F. and R.G. Ackman. 47(3): 421-426, 1970. Table IB, Note 28.


(ii) [Reserved]


(24) Lachat Instruments, 6645 W. Mill Road, Milwaukee WI 53218, Telephone: 414-358-4200.


(i) QuikChem Method 10-204-00-1-X, Digestion and Distillation of Total Cyanide in Drinking and Wastewaters using MICRO DIST and Determination of Cyanide by Flow Injection Analysis. Revision 2.2, March 2005. Table IB, Note 56.


(ii) [Reserved]


(25) Leck Mitchell, Ph.D., P.E., 656 Independence Valley Dr., Grand Junction CO 81507. Telephone: 970-244-8661.


(i) Mitchell Method M5271, Determination of Turbidity by Nephelometry. Revision 1.0, July 31, 2008. Table IB, Note 66.


(ii) Mitchell Method M5331, Determination of Turbidity by Nephelometry. Revision 1.0, July 31, 2008. Table IB, Note 65.


(26) MACHEREY-NAGEL GmbH and Co., 2850 Emrick Blvd. Bethlehem, PA 18020. Telephone: 888-321-6224.


(i) Method 036/038 NANOCOLOR® COD LR/HR, Spectrophotometric Measurement of Chemical Oxygen Demand in Water and Wastewater, Revision 1.5, May 2018. Table IB, Note 83.


(ii) [Reserved]


(27) Micrology Laboratories, LLC, 1303 Eisenhower Drive, Goshen, IN 46526. Telephone: 574-533-3351.


(i) KwikCountTM EC Medium E. coli enzyme substrate test, Rapid Detection of E. coli in Beach Water By KwikCountTM EC Membrane Filtration. 2014. Table IH, Notes 28 and 29.


(ii) [Reserved]


(28) National Council of the Paper Industry for Air and Stream Improvements, Inc. (NCASI), 260 Madison Avenue, New York NY 10016.


(i) NCASI Method TNTP-W10900, Total Nitrogen and Total Phophorus in Pulp and Paper Biologically Treated Effluent by Alkaline Persulfate Digestion. June 2011. Table IB, Note 77.


(ii) NCASI Technical Bulletin No. 253, An Investigation of Improved Procedures for Measurement of Mill Effluent and Receiving Water Color. December 1971. Table IB, Note 18.


(iii) NCASI Technical Bulletin No. 803, An Update of Procedures for the Measurement of Color in Pulp Mill Wastewaters. May 2000. Table IB, Note 18.


(29) The Nitrate Elimination Co., Inc. (NECi), 334 Hecla St., Lake Linden NI 49945.


(i) NECi Method N07-0003, Method for Nitrate Reductase Nitrate-Nitrogen Analysis. Revision 9.0. March 2014. Table IB, Note 73.


(ii) [Reserved]


(30) Oceanography International Corporation, 512 West Loop, P.O. Box 2980, College Station TX 77840.


(i) OIC Chemical Oxygen Demand Method. 1978. Table IB, Note 13.


(ii) [Reserved]


(31) OI Analytical, Box 9010, College Station TX 77820-9010.


(i) Method OIA-1677-09, Available Cyanide by Ligand Exchange and Flow Injection Analysis (FIA). Copyright 2010. Table IB, Note 59.


(ii) Method PAI-DK01, Nitrogen, Total Kjeldahl, Block Digestion, Steam Distillation, Titrimetric Detection. Revised December 22, 1994. Table IB, Note 39.


(iii) Method PAI-DK02, Nitrogen, Total Kjeldahl, Block Digestion, Steam Distillation, Colorimetric Detection. Revised December 22, 1994. Table IB, Note 40.


(iv) Method PAI-DK03, Nitrogen, Total Kjeldahl, Block Digestion, Automated FIA Gas Diffusion. Revised December 22, 1994. Table IB, Note 41.


(32) ORION Research Corporation, 840 Memorial Drive, Cambridge, Massachusetts 02138.


(i) ORION Research Instruction Manual, Residual Chlorine Electrode Model 97-70. 1977. Table IB, Note 16.


(ii) [Reserved]


(33) Technicon Industrial Systems, Tarrytown NY 10591.


(i) Industrial Method Number 379-75WE Ammonia, Automated Electrode Method, Technicon Auto Analyzer II. February 19, 1976. Table IB, Note 7.


(ii) [Reserved]


(34) Thermo Jarrell Ash Corporation, 27 Forge Parkway, Franklin MA 02038.


(i) Method AES0029. Direct Current Plasma (DCP) Optical Emission Spectrometric Method for Trace Elemental Analysis of Water and Wastes. 1986, Revised 1991. Table IB, Note 34.


(ii) [Reserved]


(35) Thermo Scientific, 166 Cummings Center, Beverly MA 01915. Telephone: 1-800-225-1480. www.thermoscientific.com.


(i) Thermo Scientific Orion Method AQ4500, Determination of Turbidity by Nephelometry. Revision 5, March 12, 2009. Table IB, Note 67.


(ii) [Reserved]


(36) 3M Corporation, 3M Center Building 220-9E-10, St. Paul MN 55144-1000.


(i) Organochlorine Pesticides and PCBs in Wastewater Using Empore
TM Disk” Test Method 3M 0222. Revised October 28, 1994. Table IC, Note 8; Table ID, Note 8.


(ii) [Reserved]


(37) Timberline Instruments, LLC, 1880 South Flatiron Ct., Unit I, Boulder CO 80301.


(i) Timberline Amonia-001, Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Conductivity Cell Analysis. June 24, 2011. Table IB, Note 74.


(ii) [Reserved]


(38) U.S. Geological Survey (USGS), U.S. Department of the Interior, Reston, Virginia. Available from USGS Books and Open-File Reports (OFR) Section, Federal Center, Box 25425, Denver, CO 80225.


(i) Colorimetric determination of nitrate plus nitrite in water by enzymatic reduction, automated discrete analyzer methods. U.S. Geological Survey Techniques and Methods, Book 5—Laboratory Analysis, Section B—Methods of the National Water Quality Laboratory, Chapter 8. 2011. Table IB, Note 72.


(ii) Determination of Heat Purgeable and Ambient Purgeable Volatile Organic Compounds in Water by Gas Chromatography/Mass Spectrometry. Chapter 12 of Section B, Methods of the National Water Quality Laboratory, of Book 5, Laboratory Analysis. 2016.


(iii) Methods for Determination of Inorganic Substances in Water and Fluvial Sediments, editors, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A1. 1979. Table IB, Note 8.


(iv) Methods for Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A1. 1989. Table IB, Notes 2 and 79.


(v) Methods for the Determination of Organic Substances in Water and Fluvial Sediments. Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 5, Chapter A3. 1987. Table IB, Note 24; Table ID, Note 4.


(vi) OFR 76-177, Selected Methods of the U.S. Geological Survey of Analysis of Wastewaters. 1976. Table IE, Note 2.


(vii) OFR 91-519, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Organonitrogen Herbicides in Water by Solid-Phase Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry With Selected-Ion Monitoring. 1992. Table ID, Note 14.


(viii) OFR 92-146, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Total Phosphorus by a Kjeldahl Digestion Method and an Automated Colorimetric Finish That Includes Dialysis. 1992. Table IB, Note 48.


(ix) OFR 93-125, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments. 1993. Table IB, Note 51 and 80; Table IC, Note 9.


(x) OFR 93-449, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Chromium in Water by Graphite Furnace Atomic Absorption Spectrophotometry. 1993. Table IB, Note 46.


(xi) OFR 94-37, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Triazine and Other Nitrogen-containing Compounds by Gas Chromatography with Nitrogen Phosphorus Detectors. 1994. Table ID, Note 9.


(xii) OFR 95-181, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Pesticides in Water by C-18 Solid-Phase Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry With Selected-Ion Monitoring. 1995. Table ID, Note 11.


(xiii) OFR 97-198, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Molybdenum in Water by Graphite Furnace Atomic Absorption Spectrophotometry. 1997. Table IB, Note 47.


(xiv) OFR 97-829, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory— Determination of 86 Volatile Organic Compounds in Water by Gas Chromatography/Mass Spectrometry, Including Detections Less Than Reporting Limits. 1999. Table IC, Note 13.


(xv) OFR 98-165, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Elements in Whole-Water Digests Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry. 1998. Table IB, Notes 50 and 81.


(xvi) OFR 98-639, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Arsenic and Selenium in Water and Sediment by Graphite Furnace—Atomic Absorption Spectrometry. 1999. Table IB, Note 49.


(xvii) OFR 00-170, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Ammonium Plus Organic Nitrogen by a Kjeldahl Digestion Method and an Automated Photometric Finish that Includes Digest Cleanup by Gas Diffusion. 2000. Table IB, Note 45.


(xviii) Techniques and Methods Book 5-B1, Determination of Elements in Natural-Water, Biota, Sediment and Soil Samples Using Collision/Reaction Cell Inductively Coupled Plasma-Mass Spectrometry. Chapter 1, Section B, Methods of the National Water Quality Laboratory, Book 5, Laboratory Analysis. 2006. Table IB, Note 70.


(xix) U.S. Geological Survey Techniques of Water-Resources Investigations, Book 5, Laboratory Analysis, Chapter A4, Methods for Collection and Analysis of Aquatic Biological and Microbiological Samples. 1989. Table IA, Note 4; Table IH, Note 4.


(xx) Water-Resources Investigation Report 01-4098, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Moderate-Use Pesticides and Selected Degradates in Water by C-18 Solid-Phase Extraction and Gas Chromatography/Mass Spectrometry. 2001. Table ID, Note 13.


(xxi) Water-Resources Investigations Report 01-4132, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Organic Plus Inorganic Mercury in Filtered and Unfiltered Natural Water With Cold Vapor-Atomic Fluorescence Spectrometry. 2001. Table IB, Note 71.


(xxii) Water-Resources Investigation Report 01-4134, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Pesticides in Water by Graphitized Carbon-Based Solid-Phase Extraction and High-Performance Liquid Chromatography/Mass Spectrometry. 2001. Table ID, Note 12.


(xxiii) Water Temperature—Influential Factors, Field Measurement and Data Presentation, Techniques of Water-Resources Investigations of the U.S. Geological Survey, Book 1, Chapter D1. 1975. Table IB, Note 32.


(39) Waters Corporation, 34 Maple Street, Milford MA 01757, Telephone: 508-482-2131, Fax: 508-482-3625.


(i) Method D6508, Test Method for Determination of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate Electrolyte. Revision 2, December 2000. Table IB, Note 54.


(ii) [Reserved]


(c) Under certain circumstances, the Director may establish limitations on the discharge of a parameter for which there is no test procedure in this part or in 40 CFR parts 405 through 499. In these instances the test procedure shall be specified by the Director.


(d) Under certain circumstances, the Administrator may approve additional alternate test procedures for nationwide use, upon recommendation by the Alternate Test Procedure Program Coordinator, Washington, DC.


(e) Sample preservation procedures, container materials, and maximum allowable holding times for parameters are cited in Tables IA, IB, IC, ID, IE, IF, IG, and IH are prescribed in Table II. Information in the table takes precedence over information in specific methods or elsewhere. Any person may apply for a change from the prescribed preservation techniques, container materials, and maximum holding times applicable to samples taken from a specific discharge. Applications for such limited use changes may be made by letters to the Regional Alternative Test Procedure (ATP) Program Coordinator or the permitting authority in the Region in which the discharge will occur. Sufficient data should be provided to assure such changes in sample preservation, containers or holding times do not adversely affect the integrity of the sample. The Regional ATP Coordinator or permitting authority will review the application and then notify the applicant and the appropriate State agency of approval or rejection of the use of the alternate test procedure. A decision to approve or deny any request on deviations from the prescribed Table II requirements will be made within 90 days of receipt of the application by the Regional Administrator. An analyst may not modify any sample preservation and/or holding time requirements of an approved method unless the requirements of this section are met.


Table II—Required Containers, Preservation Techniques, and Holding Times

Parameter number/name
Container 1
Preservation 2 3
Maximum holding time 4
Table IA—Bacterial Tests
1-4. Coliform, total, fecal, and E. coliPA, GCool, 2S2O3 58 hours.22 23
5. Fecal streptococciPA, GCool, 2S2O3 58 hours.22
6. EnterococciPA, GCool, 2S2O3 58 hours.22
7. SalmonellaPA, GCool, 2S2O3 58 hours.22
Table IA—Aquatic Toxicity Tests
8-11. Toxicity, acute and chronicP, FP, GCool, ≤6 °C 1636 hours.
Table IB—Inorganic Tests
1. AcidityP, FP, GCool, ≤6 °C 1814 days.
2. AlkalinityP, FP, GCool, ≤6 °C 1814 days.
4. AmmoniaP, FP, GCool, ≤6 °C 18, H2SO4 to pH 28 days.
9. Biochemical oxygen demandP, FP, GCool, ≤6 °C 1848 hours.
10. BoronP, FP, or QuartzHNO3 to pH 6 months.
11. BromideP, FP, GNone required28 days.
14. Biochemical oxygen demand, carbonaceousP, FP GCool, ≤6 °C 1848 hours.
15. Chemical oxygen demandP, FP, GCool, ≤6 °C 18, H2SO4 to pH 28 days.
16. ChlorideP, FP, GNone required28 days.
17. Chlorine, total residualP, GNone requiredAnalyze within 15 minutes.
21. ColorP, FP, GCool, ≤6 °C 1848 hours.
23-24. Cyanide, total or available (or CATC) and freeP, FP, GCool, ≤6 °C 18, NaOH to pH >10 5 6, reducing agent if oxidizer present14 days.
25. FluoridePNone required28 days.
27. HardnessP, FP, GHNO3 or H2SO4 to pH 6 months.
28. Hydrogen ion (pH)P, FP, GNone requiredAnalyze within 15 minutes.
31, 43. Kjeldahl and organic NP, FP, GCool, ≤6 °C 18, H2SO4 to pH 28 days.
Table IB—Metals 7
18. Chromium VIP, FP, GCool, ≤6 °C 18, pH = 9.3-9.7 2028 days.
35. Mercury (CVAA)P, FP, GHNO3 to pH 28 days.
35. Mercury (CVAFS)FP, G; and FP-lined cap 175 mL/L 12N HCl or 5 mL/L BrCl 1790 days.17
3, 5-8, 12, 13, 19, 20, 22, 26, 29, 30, 32-34, 36, 37, 45, 47, 51, 52, 58-60, 62, 63, 70-72, 74, 75. Metals, except boron, chromium VI, and mercuryP, FP, GHNO3 to pH 196 months.
38. NitrateP, FP, GCool, ≤6 °C 1848 hours.
39. Nitrate-nitriteP, FP, GCool, ≤6 °C 18, H2SO4 to pH 28 days.
40. NitriteP, FP, GCool, ≤6 °C 1848 hours.
41. Oil and greaseGCool to ≤6 °C 18, HCl or H2SO4 to pH 28 days.
42. Organic CarbonP, FP, GCool to ≤6 °C 18, HCl, H2SO4, or H3PO4 to pH 28 days.
44. OrthophosphateP, FP, GCool, to ≤6 °C 18 24Filter within 15 minutes; Analyze within 48 hours.
46. Oxygen, Dissolved ProbeG, Bottle and topNone requiredAnalyze within 15 minutes.
47. WinklerG, Bottle and topFix on site and store in dark8 hours.
48. PhenolsGCool, ≤6 °C 18, H2SO4 to pH 28 days.
49. Phosphorus (elemental)GCool, ≤6 °C 1848 hours.
50. Phosphorus, totalP, FP, GCool, ≤6 °C 18, H2SO4 to pH 28 days.
53. Residue, totalP, FP, GCool, ≤6 °C 187 days.
54. Residue, Filterable (TDS)P, FP, GCool, ≤6 °C 187 days.
55. Residue, Nonfilterable (TSS)P, FP, GCool, ≤6 °C 187 days.
56. Residue, SettleableP, FP, GCool, ≤6 °C 1848 hours.
57. Residue, VolatileP, FP, GCool, ≤6 °C 187 days.
61. SilicaP or QuartzCool, ≤6 °C 1828 days.
64. Specific conductanceP, FP, GCool, ≤6 °C 1828 days.
65. SulfateP, FP, GCool, ≤6 °C 1828 days.
66. SulfideP, FP, GCool, ≤6 °C 18, add zinc acetate plus sodium hydroxide to pH >97 days.
67. SulfiteP, FP, GNone requiredAnalyze within 15 minutes.
68. SurfactantsP, FP, GCool, ≤6 °C 1848 hours.
69. TemperatureP, FP, GNone requiredAnalyze within 15 minutes.
73. TurbidityP, FP, GCool, ≤6 °C 1848 hours.
Table IC—Organic Tests 8
13, 18-20, 22, 24, 25, 27, 28, 34-37, 39-43, 45-47, 56, 76, 104, 105, 108-111, 113. Purgeable HalocarbonsG, FP-lined septumCool, ≤6 °C 18, 0.008% Na2S2O3 5, HCl to pH 2 914 days.9
26. 2-Chloroethylvinyl etherG, FP-lined septumCool, ≤6 °C 18, 0.008% Na2S2O3 514 days.
6, 57, 106. Purgeable aromatic hydrocarbonsG, FP-lined septumCool, ≤6 °C 18, 0.008% Na2S2O3 5, HCl to pH 2 914 days.9
3, 4. Acrolein and acrylonitrileG, FP-lined septumCool, ≤6 °C 18, 0.008% Na2S2O3, pH to 4-5 1014 days.10
23, 30, 44, 49, 53, 77, 80, 81, 98, 100, 112. Phenols 11G, FP-lined capCool, ≤6 °C 18, 0.008% Na2S2O37 days until extraction, 40 days after extraction.
7, 38. Benzidines 11 12G, FP-lined capCool, ≤6 °C 18, 0.008% Na2S2O3 57 days until extraction.13
14, 17, 48, 50-52. Phthalate esters 11G, FP-lined capCool, ≤6 °C 187 days until extraction, 40 days after extraction.
82-84. Nitrosamines 11 14G, FP-lined capCool, ≤6 °C 18, store in dark, 0.008% Na2S2O3 57 days until extraction, 40 days after extraction.
88-94. PCBs 11G, FP-lined capCool, ≤6 °C 181 year until extraction, 1 year after extraction.
54, 55, 75, 79. Nitroaromatics and isophorone 11G, FP-lined capCool, ≤6 °C 18, store in dark, 0.008% Na2S2O3 57 days until extraction, 40 days after extraction.
1, 2, 5, 8-12, 32, 33, 58, 59, 74, 78, 99, 101. Polynuclear aromatic hydrocarbons 11G, FP-lined capCool, ≤6 °C 18, store in dark, 0.008% Na2S2O3 57 days until extraction, 40 days after extraction.
15, 16, 21, 31, 87. Haloethers 11G, FP-lined capCool, ≤6 °C 18, 0.008% Na2S2O3 57 days until extraction, 40 days after extraction.
29, 35-37, 63-65, 73, 107. Chlorinated hydrocarbons 11G, FP-lined capCool, ≤6 °C 187 days until extraction, 40 days after extraction.
60-62, 66-72, 85, 86, 95-97, 102, 103. CDDs/CDFs 11GSee footnote 11See footnote 11.
Aqueous Samples: Field and Lab PreservationGCool, ≤6 °C 18, 0.008% Na2S2O3 5, pH 1 year.
Solids and Mixed-Phase Samples: Field PreservationGCool, ≤6 °C 187 days.
Tissue Samples: Field PreservationGCool, ≤6 °C 1824 hours.
Solids, Mixed-Phase, and Tissue Samples: Lab PreservationGFreeze, ≤−10 °C1 year.
114-118. Alkylated phenolsGCool, 2SO4 to pH 28 days until extraction, 40 days after extraction.
119. Adsorbable Organic Halides (AOX)GCool, 2S2O3, HNO3 to pH Hold at least 3 days, but not more than 6 months.
120. Chlorinated PhenolicsG, FP-lined capCool, 2S2O3, H2SO4 to pH 30 days until acetylation, 30 days after acetylation.
Table ID—Pesticides Tests
1-70. Pesticides 11G, FP-lined capCool, ≤6 °C 18, pH 5-9 157 days until extraction, 40 days after extraction.
Table IE—Radiological Tests
1-5. Alpha, beta, and radiumP, FP, GHNO3 to pH 6 months.
Table IH—Bacterial Tests
1, 2. Coliform, total, fecalPA, GCool, 2S2O3 58 hours.22
3.E. coliPA, GCool, 2S2O3 58 hours.22
4. Fecal streptococciPA, GCool, 2S2O3 58 hours.22
5. EnterococciPA, GCool, 2S2O3 58 hours.22
Table IH—Protozoan Tests
6. CryptosporidiumLDPE; field filtration1-10 °C96 hours.21
7. GiardiaLDPE; field filtration1-10 °C96 hours.21

1 ”P” is for polyethylene; “FP” is fluoropolymer (polytetrafluoroethylene [PTFE]; Teflon®), or other fluoropolymer, unless stated otherwise in this Table II; “G” is glass; “PA” is any plastic that is made of a sterilizable material (polypropylene or other autoclavable plastic); “LDPE” is low density polyethylene.

2 Except where noted in this Table II and the method for the parameter, preserve each grab sample within 15 minutes of collection. For a composite sample collected with an automated sample (e.g., using a 24-hour composite sample; see 40 CFR 122.21(g)(7)(i) or 40 CFR part 403, appendix E), refrigerate the sample at ≤6 °C during collection unless specified otherwise in this Table II or in the method(s). For a composite sample to be split into separate aliquots for preservation and/or analysis, maintain the sample at ≤6 °C, unless specified otherwise in this Table II or in the method(s), until collection, splitting, and preservation is completed. Add the preservative to the sample container prior to sample collection when the preservative will not compromise the integrity of a grab sample, a composite sample, or aliquot split from a composite sample within 15 minutes of collection. If a composite measurement is required but a composite sample would compromise sample integrity, individual grab samples must be collected at prescribed time intervals (e.g., 4 samples over the course of a day, at 6-hour intervals). Grab samples must be analyzed separately and the concentrations averaged. Alternatively, grab samples may be collected in the field and composited in the laboratory if the compositing procedure produces results equivalent to results produced by arithmetic averaging of results of analysis of individual grab samples. For examples of laboratory compositing procedures, see EPA Method 1664 Rev. A (oil and grease) and the procedures at 40 CFR 141.24(f)(14)(iv) and (v) (volatile organics).

3 When any sample is to be shipped by common carrier or sent via the U.S. Postal Service, it must comply with the Department of Transportation Hazardous Materials Regulations (49 CFR part 172). The person offering such material for transportation is responsible for ensuring such compliance. For the preservation requirement of Table II, the Office of Hazardous Materials, Materials Transportation Bureau, Department of Transportation has determined that the Hazardous Materials Regulations do not apply to the following materials: Hydrochloric acid (HCl) in water solutions at concentrations of 0.04% by weight or less (pH about 1.96 or greater; Nitric acid (HNO3) in water solutions at concentrations of 0.15% by weight or less (pH about 1.62 or greater); Sulfuric acid (H2SO4) in water solutions at concentrations of 0.35% by weight or less (pH about 1.15 or greater); and Sodium hydroxide (NaOH) in water solutions at concentrations of 0.080% by weight or less (pH about 12.30 or less).

4 Samples should be analyzed as soon as possible after collection. The times listed are the maximum times that samples may be held before the start of analysis and still be considered valid. Samples may be held for longer periods only if the permittee or monitoring laboratory have data on file to show that, for the specific types of samples under study, the analytes are stable for the longer time, and has received a variance from the Regional ATP Coordinator under § 136.3(e). For a grab sample, the holding time begins at the time of collection. For a composite sample collected with an automated sampler (e.g., using a 24-hour composite sampler; see 40 CFR 122.21(g)(7)(i) or 40 CFR part 403, appendix E), the holding time begins at the time of the end of collection of the composite sample. For a set of grab samples composited in the field or laboratory, the holding time begins at the time of collection of the last grab sample in the set. Some samples may not be stable for the maximum time period given in the table. A permittee or monitoring laboratory is obligated to hold the sample for a shorter time if it knows that a shorter time is necessary to maintain sample stability. See § 136.3(e) for details. The date and time of collection of an individual grab sample is the date and time at which the sample is collected. For a set of grab samples to be composited, and that are all collected on the same calendar date, the date of collection is the date on which the samples are collected. For a set of grab samples to be composited, and that are collected across two calendar dates, the date of collection is the dates of the two days; e.g., November 14-15. For a composite sample collected automatically on a given date, the date of collection is the date on which the sample is collected. For a composite sample collected automatically, and that is collected across two calendar dates, the date of collection is the dates of the two days; e.g., November 14-15. For static-renewal toxicity tests, each grab or composite sample may also be used to prepare test solutions for renewal at 24 h, 48 h, and/or 72 h after first use, if stored at 0-6 °C, with minimum head space.

5 ASTM D7365-09a specifies treatment options for samples containing oxidants (e.g., chlorine) for cyanide analyses. Also, Section 9060A of Standard Methods for the Examination of Water and Wastewater (23rd edition) addresses dechlorination procedures for microbiological analyses.

6 Sampling, preservation and mitigating interferences in water samples for analysis of cyanide are described in ASTM D7365-09a (15). There may be interferences that are not mitigated by the analytical test methods or D7365-09a (15). Any technique for removal or suppression of interference may be employed, provided the laboratory demonstrates that it more accurately measures cyanide through quality control measures described in the analytical test method. Any removal or suppression technique not described in D7365-09a (15) or the analytical test method must be documented along with supporting data.

7 For dissolved metals, filter grab samples within 15 minutes of collection and before adding preservatives. For a composite sample collected with an automated sampler (e.g., using a 24-hour composite sampler; see 40 CFR 122.21(g)(7)(i) or 40 CFR part 403, appendix E), filter the sample within 15 minutes after completion of collection and before adding preservatives. If it is known or suspected that dissolved sample integrity will be compromised during collection of a composite sample collected automatically over time (e.g., by interchange of a metal between dissolved and suspended forms), collect and filter grab samples to be composited (footnote 2) in place of a composite sample collected automatically.

8 Guidance applies to samples to be analyzed by GC, LC, or GC/MS for specific compounds.

9 If the sample is not adjusted to pH 2, then the sample must be analyzed within seven days of sampling.

10 The pH adjustment is not required if acrolein will not be measured. Samples for acrolein receiving no pH adjustment must be analyzed within 3 days of sampling.

11 When the extractable analytes of concern fall within a single chemical category, the specified preservative and maximum holding times should be observed for optimum safeguard of sample integrity (i.e., use all necessary preservatives and hold for the shortest time listed). When the analytes of concern fall within two or more chemical categories, the sample may be preserved by cooling to ≤6 °C, reducing residual chlorine with 0.008% sodium thiosulfate, storing in the dark, and adjusting the pH to 6-9; samples preserved in this manner may be held for seven days before extraction and for forty days after extraction. Exceptions to this optional preservation and holding time procedure are noted in footnote 5 (regarding the requirement for thiosulfate reduction), and footnotes 12, 13 (regarding the analysis of benzidine).

12 If 1,2-diphenylhydrazine is likely to be present, adjust the pH of the sample to 4.0 ± 0.2 to prevent rearrangement to benzidine.

13 Extracts may be stored up to 30 days at

14 For the analysis of diphenylnitrosamine, add 0.008% Na2S2O3 and adjust pH to 7-10 with NaOH within 24 hours of sampling.

15 The pH adjustment may be performed upon receipt at the laboratory and may be omitted if the samples are extracted within 72 hours of collection. For the analysis of aldrin, add 0.008% Na2S2O3.

16 Place sufficient ice with the samples in the shipping container to ensure that ice is still present when the samples arrive at the laboratory. However, even if ice is present when the samples arrive, immediately measure the temperature of the samples and confirm that the preservation temperature maximum has not been exceeded. In the isolated cases where it can be documented that this holding temperature cannot be met, the permittee can be given the option of on-site testing or can request a variance. The request for a variance should include supportive data which show that the toxicity of the effluent samples is not reduced because of the increased holding temperature. Aqueous samples must not be frozen. Hand-delivered samples used on the day of collection do not need to be cooled to 0 to 6 °C prior to test initiation.

17 Samples collected for the determination of trace level mercury (

18 Aqueous samples must be preserved at ≤6 °C, and should not be frozen unless data demonstrating that sample freezing does not adversely impact sample integrity is maintained on file and accepted as valid by the regulatory authority. Also, for purposes of NPDES monitoring, the specification of “≤ °C” is used in place of the “4 °C” and “

19 An aqueous sample may be collected and shipped without acid preservation. However, acid must be added at least 24 hours before analysis to dissolve any metals that adsorb to the container walls. If the sample must be analyzed within 24 hours of collection, add the acid immediately (see footnote 2). Soil and sediment samples do not need to be preserved with acid. The allowances in this footnote supersede the preservation and holding time requirements in the approved metals methods.

20 To achieve the 28-day holding time, use the ammonium sulfate buffer solution specified in EPA Method 218.6. The allowance in this footnote supersedes preservation and holding time requirements in the approved hexavalent chromium methods, unless this supersession would compromise the measurement, in which case requirements in the method must be followed.

21 Holding time is calculated from time of sample collection to elution for samples shipped to the laboratory in bulk and calculated from the time of sample filtration to elution for samples filtered in the field.

22 Sample analysis should begin as soon as possible after receipt; sample incubation must be started no later than 8 hours from time of collection.

23 For fecal coliform samples for sewage sludge (biosolids) only, the holding time is extended to 24 hours for the following sample types using either EPA Method 1680 (LTB-EC) or 1681 (A-1): Class A composted, Class B aerobically digested, and Class B anaerobically digested.

24 The immediate filtration requirement in orthophosphate measurement is to assess the dissolved or bio-available form of orthophosphorus (i.e., that which passes through a 0.45-micron filter), hence the requirement to filter the sample immediately upon collection (i.e., within 15 minutes of collection).


[38 FR 28758, Oct. 16, 1973]


Editorial Note:For Federal Register citations affecting § 136.3, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

§ 136.4 Application for and approval of alternate test procedures for nationwide use.

(a) A written application for review of an alternate test procedure (alternate method) for nationwide use may be made by letter via email or by hard copy in triplicate to the National Alternate Test Procedure (ATP) Program Coordinator (National Coordinator), Office of Science and Technology (4303T), Office of Water, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460. Any application for an ATP under this paragraph (a) shall:


(1) Provide the name and address of the responsible person or firm making the application.


(2) Identify the pollutant(s) or parameter(s) for which nationwide approval of an alternate test procedure is being requested.


(3) Provide a detailed description of the proposed alternate test procedure, together with references to published or other studies confirming the general applicability of the alternate test procedure for the analysis of the pollutant(s) or parameter(s) in wastewater discharges from representative and specified industrial or other categories.


(4) Provide comparability data for the performance of the proposed alternative test procedure compared to the performance of the reference method.


(b) The National Coordinator may request additional information and analyses from the applicant in order to evaluate whether the alternate test procedure satisfies the applicable requirements of this part.


(c) Approval for nationwide use. (1) After a review of the application and any additional analyses requested from the applicant, the National Coordinator will notify the applicant, in writing, of whether the National Coordinator will recommend approval or disapproval of the alternate test procedure for nationwide use in CWA programs. If the application is not recommended for approval, the National Coordinator may specify what additional information might lead to a reconsideration of the application and notify the Regional Alternate Test Procedure Coordinators of the disapproval recommendation. Based on the National Coordinator’s recommended disapproval of a proposed alternate test procedure and an assessment of any current approvals for limited uses for the unapproved method, the Regional ATP Coordinator may decide to withdraw approval of the method for limited use in the Region.


(2) Where the National Coordinator has recommended approval of an applicant’s request for nationwide use of an alternate test procedure, the National Coordinator will notify the applicant. The National Coordinator will also notify the Regional ATP Coordinators that they may consider approval of this alternate test procedure for limited use in their Regions based on the information and data provided in the application until the alternate test procedure is approved by publication in a final rule in the Federal Register.


(3) EPA will propose to amend this part to include the alternate test procedure in § 136.3. EPA shall make available for review all the factual bases for its proposal, including the method, any performance data submitted by the applicant and any available EPA analysis of those data.


(4) Following public comment, EPA shall publish in the Federal Register a final decision on whether to amend this part to include the alternate test procedure as an approved analytical method for nationwide use.


(5) Whenever the National Coordinator has recommended approval of an applicant’s ATP request for nationwide use, any person may request an approval of the method for limited use under § 136.5 from the EPA Region.


[77 FR 29809, May 18, 2012, as amended at 82 FR 40874, Aug. 28, 2017]


§ 136.5 Approval of alternate test procedures for limited use.

(a) Any person may request the Regional ATP Coordinator to approve the use of an alternate test procedure in the Region.


(b) When the request for the use of an alternate test procedure concerns use in a State with an NPDES permit program approved pursuant to section 402 of the Act, the requestor shall first submit an application for limited use to the Director of the State agency having responsibility for issuance of NPDES permits within such State (i.e., permitting authority). The Director will forward the application to the Regional ATP Coordinator with a recommendation for or against approval.


(c) Any application for approval of an alternate test procedure for limited use may be made by letter, email or by hard copy. The application shall include the following:


(1) Provide the name and address of the applicant and the applicable ID number of the existing or pending permit(s) and issuing agency for which use of the alternate test procedure is requested, and the discharge serial number.


(2) Identify the pollutant or parameter for which approval of an alternate test procedure is being requested.


(3) Provide justification for using testing procedures other than those specified in Tables IA through IH of § 136.3, or in the NPDES permit.


(4) Provide a detailed description of the proposed alternate test procedure, together with references to published studies of the applicability of the alternate test procedure to the effluents in question.


(5) Provide comparability data for the performance of the proposed alternate test procedure compared to the performance of the reference method.


(d) Approval for limited use. (1) The Regional ATP Coordinator will review the application and notify the applicant and the appropriate State agency of approval or rejection of the use of the alternate test procedure. The approval may be restricted to use only with respect to a specific discharge or facility (and its laboratory) or, at the discretion of the Regional ATP Coordinator, to all dischargers or facilities (and their associated laboratories) specified in the approval for the Region. If the application is not approved, the Regional ATP Coordinator shall specify what additional information might lead to a reconsideration of the application.


(2) The Regional ATP Coordinator will forward a copy of every approval and rejection notification to the National Alternate Test Procedure Coordinator.


[77 FR 29809, May 18, 2012, as amended at 82 FR 40875, Aug. 28, 2017]


§ 136.6 Method modifications and analytical requirements.

(a) Definitions of terms used in this section—(1) Analyst means the person or laboratory using a test procedure (analytical method) in this part.


(2) Chemistry of the method means the reagents and reactions used in a test procedure that allow determination of the analyte(s) of interest in an environmental sample.


(3) Determinative technique means the way in which an analyte is identified and quantified (e.g., colorimetry, mass spectrometry).


(4) Equivalent performance means that the modified method produces results that meet or exceed the QC acceptance criteria of the approved method.


(5) Method-defined analyte means an analyte defined solely by the method used to determine the analyte. Such an analyte may be a physical parameter, a parameter that is not a specific chemical, or a parameter that may be comprised of a number of substances. Examples of such analytes include temperature, oil and grease, total suspended solids, total phenolics, turbidity, chemical oxygen demand, and biochemical oxygen demand.


(6) QC means “quality control.”


(b) Method modifications. (1) If the underlying chemistry and determinative technique in a modified method are essentially the same as an approved Part 136 method, then the modified method is an equivalent and acceptable alternative to the approved method provided the requirements of this section are met. However, those who develop or use a modification to an approved (Part 136) method must document that the performance of the modified method, in the matrix to which the modified method will be applied, is equivalent to the performance of the approved method. If such a demonstration cannot be made and documented, then the modified method is not an acceptable alternative to the approved method. Supporting documentation must, if applicable, include the routine initial demonstration of capability and ongoing QC including determination of precision and accuracy, detection limits, and matrix spike recoveries. Initial demonstration of capability typically includes analysis of four replicates of a mid-level standard and a method detection limit study. Ongoing quality control typically includes method blanks, mid-level laboratory control samples, and matrix spikes (QC is as specified in the method). The method is considered equivalent if the quality control requirements in the reference method are achieved. Where the laboratory is using a vendor-supplied method, it is the QC criteria in the reference method, not the vendor’s method, that must be met to show equivalency. Where a sample preparation step is required (i.e., digestion, distillation), QC tests are to be run using standards treated in the same way as the samples. The method user’s Standard Operating Procedure (SOP) must clearly document the modifications made to the reference method. Examples of allowed method modifications are listed in this section. If the method user is uncertain whether a method modification is allowed, the Regional ATP Coordinator or Director should be contacted for approval prior to implementing the modification. The method user should also complete necessary performance checks to verify that acceptable performance is achieved with the method modification prior to analyses of compliance samples.


(2) Requirements. The modified method must meet or exceed performance of the approved method(s) for the analyte(s) of interest, as documented by meeting the initial and ongoing quality control requirements in the method.


(i) Requirements for establishing equivalent performance. If the approved method contains QC tests and QC acceptance criteria, the modified method must use these QC tests and the modified method must meet the QC acceptance criteria with the following conditions:


(A) The analyst may only rely on QC tests and QC acceptance criteria in a method if it includes wastewater matrix QC tests and QC acceptance criteria (e.g., matrix spikes) and both initial (start-up) and ongoing QC tests and QC acceptance criteria.


(B) If the approved method does not contain QC tests and QC acceptance criteria or if the QC tests and QC acceptance criteria in the method do not meet the requirements of this section, then the analyst must employ QC tests published in the “equivalent” of a Part 136 method that has such QC, or the essential QC requirements specified at 136.7, as applicable. If the approved method is from a compendium or VCSB and the QA/QC requirements are published in other parts of that organization’s compendium rather than within the Part 136 method then that part of the organization’s compendium must be used for the QC tests.


(C) In addition, the analyst must perform ongoing QC tests, including assessment of performance of the modified method on the sample matrix (e.g., analysis of a matrix spike/matrix spike duplicate pair for every twenty samples), and analysis of an ongoing precision and recovery sample (e.g., laboratory fortified blank or blank spike) and a blank with each batch of 20 or fewer samples.


(D) If the performance of the modified method in the wastewater matrix or reagent water does not meet or exceed the QC acceptance criteria, the method modification may not be used.


(ii) Requirements for documentation. The modified method must be documented in a method write-up or an addendum that describes the modification(s) to the approved method prior to the use of the method for compliance purposes. The write-up or addendum must include a reference number (e.g., method number), revision number, and revision date so that it may be referenced accurately. In addition, the organization that uses the modified method must document the results of QC tests and keep these records, along with a copy of the method write-up or addendum, for review by an auditor.


(3) Restrictions. An analyst may not modify an approved Clean Water Act analytical method for a method-defined analyte. In addition, an analyst may not modify an approved method if the modification would result in measurement of a different form or species of an analyte. Changes in method procedures are not allowed if such changes would alter the defined chemistry (i.e., method principle) of the unmodified method. For example, phenol method 420.1 or 420.4 defines phenolics as ferric iron oxidized compounds that react with 4-aminoantipyrine (4-AAP) at pH 10 after being distilled from acid solution. Because total phenolics represents a group of compounds that all react at different efficiencies with 4-AAP, changing test conditions likely would change the behavior of these different phenolic compounds. An analyst may not modify any sample collection, preservation, or holding time requirements of an approved method. Such modifications to sample collection, preservation, and holding time requirements do not fall within the scope of the flexibility allowed at § 136.6. Method flexibility refers to modifications of the analytical procedures used for identification and measurement of the analyte only and does not apply to sample collection, preservation, or holding time procedures, which may only be modified as specified in § 136.3(e).


(4) Allowable changes. Except as noted under paragraph (b)(3) of this section, an analyst may modify an approved test procedure (analytical method) provided that the underlying reactions and principles used in the approved method remain essentially the same, and provided that the requirements of this section are met. If equal or better performance can be obtained with an alternative reagent, then it is allowed. A laboratory wishing to use these modifications must demonstrate acceptable method performance by performing and documenting all applicable initial demonstration of capability and ongoing QC tests and meeting all applicable QC acceptance criteria as described in § 136.7. Some examples of the allowed types of changes, provided the requirements of this section are met include:


(i) Changes between manual method, flow analyzer, and discrete instrumentation.


(ii) Changes in chromatographic columns or temperature programs.


(iii) Changes between automated and manual sample preparation, such as digestions, distillations, and extractions; in-line sample preparation is an acceptable form of automated sample preparation for CWA methods.


(iv) In general, ICP-MS is a sensitive and selective detector for metal analysis; however isobaric interference can cause problems for quantitative determination, as well as identification based on the isotope pattern. Interference reduction technologies, such as collision cells or reaction cells, are designed to reduce the effect of spectroscopic interferences that may bias results for the element of interest. The use of interference reduction technologies is allowed, provided the method performance specifications relevant to ICP-MS measurements are met.


(v) The use of EPA Method 200.2 or the sample preparation steps from EPA Method 1638, including the use of closed-vessel digestion, is allowed for EPA Method 200.8, provided the method performance specifications relevant to the ICP-MS are met.


(vi) Changes in pH adjustment reagents. Changes in compounds used to adjust pH are acceptable as long as they do not produce interference. For example, using a different acid to adjust pH in colorimetric methods.


(vii) Changes in buffer reagents are acceptable provided that the changes do not produce interferences.


(viii) Changes in the order of reagent addition are acceptable provided that the change does not alter the chemistry and does not produce an interference. For example, using the same reagents, but adding them in different order, or preparing them in combined or separate solutions (so they can be added separately), is allowed, provided reagent stability or method performance is equivalent or improved.


(ix) Changes in calibration range (provided that the modified range covers any relevant regulatory limit and the method performance specifications for calibration are met).


(x) Changes in calibration model. (A) Linear calibration models do not adequately fit calibration data with one or two inflection points. For example, vendor-supplied data acquisition and processing software on some instruments may provide quadratic fitting functions to handle such situations. If the calibration data for a particular analytical method routinely display quadratic character, using quadratic fitting functions may be acceptable. In such cases, the minimum number of calibrators for second order fits should be six, and in no case should concentrations be extrapolated for instrument responses that exceed that of the most concentrated calibrator. Examples of methods with nonlinear calibration functions include chloride by SM4500-Cl-E-1997, hardness by EPA Method 130.1, cyanide by ASTM D6888 or OIA1677, Kjeldahl nitrogen by PAI-DK03, and anions by EPA Method 300.0.


(B) As an alternative to using the average response factor, the quality of the calibration may be evaluated using the Relative Standard Error (RSE). The acceptance criterion for the RSE is the same as the acceptance criterion for Relative Standard Deviation (RSD), in the method. RSE is calculated as:




Where:

x′i = Calculated concentration at level i

xi = Actual concentration of the calibration level i

n = Number of calibration points

p = Number of terms in the fitting equation (average = 1, linear = 2, quadratic = 3)

(C) Using the RSE as a metric has the added advantage of allowing the same numerical standard to be applied to the calibration model, regardless of the form of the model. Thus, if a method states that the RSD should be ≤20% for the traditional linear model through the origin, then the RSE acceptance limit can remain ≤20% as well. Similarly, if a method provides an RSD acceptance limit of ≤15%, then that same figure can be used as the acceptance limit for the RSE. The RSE may be used as an alternative to correlation coefficients and coefficients of determination for evaluating calibration curves for any of the methods at part 136. If the method includes a numerical criterion for the RSD, then the same numerical value is used for the RSE. Some older methods do not include any criterion for the calibration curve—for these methods, if RSE is used the value should be ≤20%. Note that the use of the RSE is included as an alternative to the use of the correlation coefficient as a measure of the suitability of a calibration curve. It is not necessary to evaluate both the RSE and the correlation coefficient.


(xi) Changes in equipment such as equipment from a vendor different from the one specified in the method.


(xii) The use of micro or midi distillation apparatus in place of macro distillation apparatus.


(xiii) The use of prepackaged reagents.


(xiv) The use of digital titrators and methods where the underlying chemistry used for the determination is similar to that used in the approved method.


(xv) Use of selected ion monitoring (SIM) mode for analytes that cannot be effectively analyzed in full-scan mode and reach the required sensitivity. False positives are more of a concern when using SIM analysis, so at a minimum, one quantitation and two qualifying ions must be monitored for each analyte (unless fewer than three ions with intensity greater than 15% of the base peak are available). The ratio of each of the two qualifying ions to the quantitation ion must be evaluated and should agree with the ratio observed in an authentic standard within ±20 percent. Analyst judgment must be applied to the evaluation of ion ratios because the ratios can be affected by co-eluting compounds present in the sample matrix. The signal-to-noise ratio of the least sensitive ion should be at least 3:1. Retention time in the sample should match within 0.05 minute of an authentic standard analyzed under identical conditions. Matrix interferences can cause minor shifts in retention time and may be evident as shifts in the retention times of the internal standards. The total scan time should be such that a minimum of eight scans are obtained per chromatographic peak.


(xvi) Changes are allowed in purge-and-trap sample volumes or operating conditions. Some examples are:


(A) Changes in purge time and purge-gas flow rate. A change in purge time and purge-gas flow rate is allowed provided that sufficient total purge volume is used to achieve the required minimum detectible concentration and calibration range for all compounds. In general, a purge rate in the range 20-200 mL/min and a total purge volume in the range 240-880 mL are recommended.


(B) Use of nitrogen or helium as a purge gas, provided that the required sensitivities for all compounds are met.


(C) Sample temperature during the purge state. Gentle heating of the sample during purging (e.g., 40 °C) increases purging efficiency of hydrophilic compounds and may improve sample-to-sample repeatability because all samples are purged under precisely the same conditions.


(D) Trap sorbent. Any trap design is acceptable, provided that the data acquired meet all QC criteria.


(E) Changes to the desorb time. Shortening the desorb time (e.g., from4 minutes to 1 minute) may not affect compound recoveries, and can shorten overall cycle time and significantly reduce the amount of water introduced to the analytical system, thus improving the precision of analysis, especially for water-soluble analytes. A desorb time of four minutes is recommended, however a shorter desorb time may be used, provided that all QC specifications in the method are met.


(F) Use of water management techniques is allowed. Water is always collected on the trap along with the analytes and is a significant interference for analytical systems (GC and GC/MS). Modern water management techniques (e.g., dry purge or condensation points) can remove moisture from the sample stream and improve analytical performance.


(xvii) If the characteristics of a wastewater matrix prevent efficient recovery of organic pollutants and prevent the method from meeting QC requirements, the analyst may attempt to resolve the issue by adding salts to the sample, provided that such salts do not react with or introduce the target pollutant into the sample (as evidenced by the analysis of method blanks, laboratory control samples, and spiked samples that also contain such salts), and that all requirements of paragraph (b)(2) of this section are met. Samples having residual chlorine or other halogen must be dechlorinated prior to the addition of such salts.


(xviii) If the characteristics of a wastewater matrix result in poor sample dispersion or reagent deposition on equipment and prevent the analyst from meeting QC requirements, the analyst may attempt to resolve the issue by adding a inert surfactant that does not affect the chemistry of the method, such as Brij-35 or sodium dodecyl sulfate (SDS), provided that such surfactant does not react with or introduce the target pollutant into the sample (as evidenced by the analysis of method blanks, laboratory control samples, and spiked samples that also contain such surfactant) and that all requirements of paragraph (b)(1) and (b)(2) of this section are met. Samples having residual chlorine or other halogen must be dechlorinated prior to the addition of such surfactant.


(xix) The use of gas diffusion (using pH change to convert the analyte to gaseous form and/or heat to separate an analyte contained in steam from the sample matrix) across a hydrophobic semi-permeable membrane to separate the analyte of interest from the sample matrix may be used in place of manual or automated distillation in methods for analysis such as ammonia, total cyanide, total Kjeldahl nitrogen, and total phenols. These procedures do not replace the digestion procedures specified in the approved methods and must be used in conjunction with those procedures.


(xx) Changes in equipment operating parameters such as the monitoring wavelength of a colorimeter or the reaction time and temperature as needed to achieve the chemical reactions defined in the unmodified CWA method. For example, molybdenum blue phosphate methods have two absorbance maxima, one at about 660 nm and another at about 880 nm. The former is about 2.5 times less sensitive than the latter. Wavelength choice provides a cost-effective, dilution-free means to increase sensitivity of molybdenum blue phosphate methods.


(xxi) Interchange of oxidants, such as the use of titanium oxide in UV-assisted automated digestion of TOC and total phosphorus, as long as complete oxidation can be demonstrated.


(xxii) Use of an axially viewed torch with Method 200.7.


(xxiii) When analyzing metals by inductively coupled plasma-atomic emission spectroscopy, inductively coupled plasma-mass spectrometry, and stabilized temperature graphite furnace atomic absorption, closed-vessel microwave digestion of wastewater samples is allowed as alternative heating source for Method 200.2—“Sample Preparation Procedure for Spectrochemical Determination of Total Recoverable Elements” for the following elements: Aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, potassium, selenium, silver, sodium, thallium, tin, titanium, vanadium, zinc, provided the performance specifications in the relevant determinative method are met. (Note that this list does not include Mercury.) Each laboratory determining total recoverable metals is required to operate a formal quality control (QC) program. The minimum requirements include initial demonstration of capability, method detection limit (MDL), analysis of reagent blanks, fortified blanks, matrix spike samples, and blind proficiency testing samples, as continuing quality control checks on performance. The laboratory is required to maintain performance records on file that define the quality of the data generated.


(c) The permittee must notify their permitting authority of the intent to use a modified method. Such notification should be of the form “Method xxx has been modified within the flexibility allowed in 40 CFR 136.6.” The permittee may indicate the specific paragraph of § 136.6 allowing the method modification. Specific details of the modification need not be provided, but must be documented in the Standard Operating Procedure (SOP) and maintained by the analytical laboratory that performs the analysis.


[77 FR 29810, May 18, 2012, as amended at 82 FR 40875, Aug. 28, 2017; 86 FR 27260, May 19, 2021]


§ 136.7 Quality assurance and quality control.

The permittee/laboratory shall use suitable QA/QC procedures when conducting compliance analyses with any part 136 chemical method or an alternative method specified by the permitting authority. These QA/QC procedures are generally included in the analytical method or may be part of the methods compendium for approved Part 136 methods from a consensus organization. For example, Standard Methods contains QA/QC procedures in the Part 1000 section of the Standard Methods Compendium. The permittee/laboratory shall follow these QA/QC procedures, as described in the method or methods compendium. If the method lacks QA/QC procedures, the permittee/laboratory has the following options to comply with the QA/QC requirements:


(a) Refer to and follow the QA/QC published in the “equivalent” EPA method for that parameter that has such QA/QC procedures;


(b) Refer to the appropriate QA/QC section(s) of an approved part 136 method from a consensus organization compendium;


(c)(1) Incorporate the following twelve quality control elements, where applicable, into the laboratory’s documented standard operating procedure (SOP) for performing compliance analyses when using an approved part 136 method when the method lacks such QA/QC procedures. One or more of the twelve QC elements may not apply to a given method and may be omitted if a written rationale is provided indicating why the element(s) is/are inappropriate for a specific method.


(i) Demonstration of Capability (DOC);


(ii) Method Detection Limit (MDL);


(iii) Laboratory reagent blank (LRB), also referred to as method blank (MB);


(iv) Laboratory fortified blank (LFB), also referred to as a spiked blank, or laboratory control sample (LCS);


(v) Matrix spike (MS) and matrix spike duplicate (MSD), or laboratory fortified matrix (LFM) and LFM duplicate, may be used for suspected matrix interference problems to assess precision;


(vi) Internal standards (for GC/MS analyses), surrogate standards (for organic analysis) or tracers (for radiochemistry);


(vii) Calibration (initial and continuing), also referred to as initial calibration verification (ICV) and continuing calibration verification (CCV);


(viii) Control charts (or other trend analyses of quality control results);


(ix) Corrective action (root cause analysis);


(x) QC acceptance criteria;


(xi) Definitions of preparation and analytical batches that may drive QC frequencies; and


(xii) Minimum frequency for conducting all QC elements.


(2) These twelve quality control elements must be clearly documented in the written standard operating procedure for each analytical method not containing QA/QC procedures, where applicable.


[77 FR 29813, May 18, 2012]


Appendix A to Part 136—Methods for Organic Chemical Analysis of Municipal and Industrial Wastewater

Method 601—Purgeable Halocarbons

1. Scope and Application

1.1 This method covers the determination of 29 purgeable halocarbons.


The following parameters may be determined by this method:


Parameter
STORET No.
CAS No.
Bromodichloromethane3210175-27-4
Bromoform3210475-25-2
Bromomethane3441374-83-9
Carbon tetrachloride3210256-23-5
Chlorobenzene34301108-90-7
Chloroethane3431175-00-3
2-Chloroethylvinyl ether34576100-75-8
Chloroform3210667-66-3
Chloromethane3441874-87-3
Dibromochloromethane32105124-48-1
1,2-Dichlorobenzene3453695-50-1
1,3-Dichlorobenzene34566541-73-1
1,4-Dichlorobenzene34571106-46-7
Dichlorodifluoromethane3466875-71-8
1,1-Dichloroethane3449675-34-3
1,2-Dichloroethane34531107-06-2
1,1-Dichloroethane3450175-35-4
trans-1,2-Dichloroethene34546156-60-5
1,2-Dichloropropane3454178-87-5
cis-1,3-Dichloropropene3470410061-01-5
trans-1,3-Dichloropropene3469910061-02-6
Methylene chloride3442375-09-2
1,1,2,2-Tetrachloroethane3451679-34-5
Tetrachloroethene34475127-18-4
1,1,1-Trichloroethane3450671-55-6
1,1,2-Trichloroethane3451179-00-5
Tetrachloroethene3918079-01-6
Trichlorofluoromethane3448875-69-4
Vinyl chloride3971575-01-4

1.2 This is a purge and trap gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 624 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for most of the parameters listed above.


1.3 The method detection limit (MDL, defined in Section 12.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.5 This method is restricted to use by or under the supervision of analysts experienced in the operation of a purge and trap system and a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 An inert gas is bubbled through a 5-mL water sample contained in a specially-designed purging chamber at ambient temperature. The halocarbons are efficiently transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the halocarbons are trapped. After purging is completed, the trap is heated and backflushed with the inert gas to desorb the halocarbons onto a gas chromatographic column. The gas chromatograph is temperature programmed to separate the halocarbons which are then detected with a halide-specific detector.
2 3


2.2 The method provides an optional gas chromatographic column that may be helpful in resolving the compounds of interest from interferences that may occur.


3. Interferences

3.1 Impurities in the purge gas and organic compounds outgassing from the plumbing ahead of the trap account for the majority of contamination problems. The analytical system must be demonstrated to be free from contamination under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3. The use of non-Teflon plastic tubing, non-Teflon thread sealants, or flow controllers with rubber components in the purge and trap system should be avoided.


3.2 Samples can be contaminated by diffusion of volatile organics (particularly fluorocarbons and methylene chloride) through the septum seal ilto the sample during shipment and storage. A field reagent blank prepared from reagent water and carried through the sampling and handling protocol can serve as a check on such contamination.


3.3 Contamination by carry-over can occur whenever high level and low level samples are sequentially analyzed. To reduce carry-over, the purging device and sample syringe must be rinsed with reagent water between sample analyses. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of reagent water to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high organohalide levels, it may be necessary to wash out the purging device with a detergent solution, rinse it with distilled water, and then dry it in a 105 °C oven between analyses. The trap and other parts of the system are also subject to contamination; therefore, frequent bakeout and purging of the entire system may be required.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4 6 for the information of the analyst.


4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: carbon tetrachloride, chloroform, 1,4-dichlorobenzene, and vinyl chloride. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete sampling.


5.1.1 Vial—25-mL capacity or larger, equipped with a screw cap with a hole in the center (Pierce #13075 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 °C before use.


5.1.2 Septum—Teflon-faced silicone (Pierce #12722 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 °C for 1 h before use.


5.2 Purge and trap system—The purge and trap system consists of three separate pieces of equipment: a purging device, trap, and desorber. Several complete systems are now commercially available.


5.2.1 The purging device must be designed to accept 5-mL samples with a water column at least 3 cm deep. The gaseous head space between the water column and the trap must have a total volume of less than 15 mL. The purge gas must pass through the water column as finely divided bubbles with a diameter of less than 3 mm at the origin. The purge gas must be introduced no more than 5 mm from the base of the water column. The purging device illustrated in Figure 1 meets these design criteria.


5.2.2 The trap must be at least 25 cm long and have an inside diameter of at least 0.105 in. The trap must be packed to contain the following minimum lengths of adsorbents: 1.0 cm of methyl silicone coated packing (Section 6.3.3), 7.7 cm of 2,6-diphenylene oxide polymer (Section 6.3.2), 7.7 cm of silica gel (Section 6.3.4), 7.7 cm of coconut charcoal (Section 6.3.1). If it is not necessary to analyze for dichlorodifluoromethane, the charcoal can be eliminated, and the polymer section lengthened to 15 cm. The minimum specifications for the trap are illustrated in Figure 2.


5.2.3 The desorber must be capable of rapidly heating the trap to 180 °C. The polymer section of the trap should not be heated higher than 180 °C and the remaining sections should not exceed 200 °C. The desorber illustrated in Figure 2 meets these design criteria.


5.2.4 The purge and trap system may be assembled as a separate unit or be coupled to a gas chromatograph as illustrated in Figures 3 and 4.


5.3 Gas chromatograph—An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.3.1 Column 1—8 ft long × 0.1 in. ID stainless steel or glass, packed with 1% SP-1000 on Carbopack B (60/80 mesh) or equivalent. This column was used to develop the method performance statements in Section 12. Guidelines for the use of alternate column packings are provided in Section 10.1.


5.3.2 Column 2—6 ft long × 0.1 in. ID stainless steel or glass, packed with chemically bonded n-octane on Porasil-C (100/120 mesh) or equivalent.


5.3.3 Detector—Electrolytic conductivity or microcoulometric detector. These types of detectors have proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1). The electrolytic conductivity detector was used to develop the method performance statements in Section 12. Guidelines for the use of alternate detectors are provided in Section 10.1.


5.4 Syringes—5-mL glass hypodermic with Luerlok tip (two each), if applicable to the purging device.


5.5 Micro syringes—25-µL, 0.006 in. ID needle.


5.6 Syringe valve—2-way, with Luer ends (three each).


5.7 Syringe—5-mL, gas-tight with shut-off valve.


5.8 Bottle—15-mL, screw-cap, with Teflon cap liner.


5.9 Balance—Analytical, capable of accurately weighing 0.0001 g.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.1.1 Reagent water can be generated by passing tap water through a carbon filter bed containing about 1 lb of activated carbon (Filtrasorb-300, Calgon Corp., or equivalent).


6.1.2 A water purification system (Millipore Super-Q or equivalent) may be used to generate reagent water.


6.1.3 Reagent water may also be prepared by boiling water for 15 min. Subsequently, while maintaining the temperature at 90 °C, bubble a contaminant-free inert gas through the water for 1 h. While still hot, transfer the water to a narrow mouth screw-cap bottle and seal with a Teflon-lined septum and cap.


6.2 Sodium thiosulfate—(ACS) Granular.


6.3 Trap Materials:


6.3.1 Coconut charcoal—6/10 mesh sieved to 26 mesh, Barnabey Cheney, CA-580-26 lot # M-2649 or equivalent.


6.3.2 2,6-Diphenylene oxide polymer—Tenax, (60/80 mesh), chromatographic grade or equivalent.


6.3.3 Methyl silicone packing—3% OV-1 on Chromosorb-W (60/80 mesh) or equivalent.


6.3.4 Silica gel—35/60 mesh, Davison, grade-15 or equivalent.


6.4 Methanol—Pesticide quality or equivalent.


6.5 Stock standard solutions—Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standard solutions in methanol using assayed liquids or gases as appropriate. Because of the toxicity of some of the organohalides, primary dilutions of these materials should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be used when the analyst handles high concentrations of such materials.


6.5.1 Place about 9.8 mL of methanol into a 10-mL ground glass stoppered volumetric flask. Allow the flask to stand, unstoppered, for about 10 min or until all alcohol wetted surfaces have dried. Weigh the flask to the learest 0.1 mg.


6.5.2 Add the assayed reference material:


6.5.2.1 Liquid—Using a 100 µL syringe, immediately add two or more drops of assayed reference material to the flask, then reweigh. Be sure that the drops fall directly into the alcohol without contacting the neck of the flask.


6.5.2.2 Gases—To prepare standards for any of the six halocarbons that boil below 30 °C (bromomethane, chloroethane, chloromethane, dichlorodifluoromethane, trichlorofluoromethane, vinyl chloride), fill a 5-mL valved gas-tight syringe with the reference standard to the 5.0-mL mark. Lower the needle to 5 mm above the methanol meniscus. Slowly introduce the reference standard above the surface of the liquid (the heavy gas will rapidly dissolve into the methanol).


6.5.3 Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in µg/µL from the net gain in weight. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the malufacturer or by an independent source.


6.5.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store, with minimal headspace, at −10 to −20 °C and protect from light.


6.5.5 Prepare fresh standards weekly for the six gases and 2-chloroethylvinyl ether. All other standards must be replaced after one month, or sooner if comparison with check standards indicates a problem.


6.6 Secondary dilution standards—Using stock standard solutions, prepare secondary dilution standards in methanol that contain the compounds of interest, either singly or mixed together. The secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in Section 7.3.1 or 7.4.1 will bracket the working range of the analytical system. Secondary dilution standards should be stored with minimal headspace and should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.7 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Assemble a purge and trap system that meets the specifications in Section 5.2. Condition the trap overnight at 180 °C by backflushing with an inert gas flow of at least 20 mL/min. Condition the trap for 10 min once daily prior to use.


7.2 Connect the purge and trap system to a gas chromatograph. The gas chromatograph must be operated using temperature and flow rate conditions equivalent to those given in Table 1. Calibrate the purge and trap-gas chromatographic system using either the external standard technique (Section 7.3) or the internal standard technique (Section 7.4).


7.3 External standard calibration procedure:


7.3.1 Prepare calibration standards at a miminum of three concentration levels for each parameter by carefully adding 20.0 µL of one or more secondary dilution standards to 100, 500, or 1000 µL of reagent water. A 25-µL syringe with a 0.006 in. ID needle should be used for this operation. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector. These aqueous standards can be stored up to 24 h, if held in sealed vials with zero headspace as described in Section 9.2. If not so stored, they must be discarded after 1 h.


7.3.2 Analyze each calibration standard according to Section 10, and tabulate peak height or area responses versus the concentration in the standard. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to concentration (calibration factor) is a constant over the working range (

7.4 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples. The compounds recommended for use as surrogate spikes in Section 8.7 have been used successfully as internal standards, because of their generally unique retention times.


7.4.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest as described in Section 7.3.1.


7.4.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 6.5 and 6.6. It is recommended that the secondary dilution standard be prepared at a concentration of 15 µg/mL of each internal standard compound. The addition of 10 µL of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30 µg/L.


7.4.3 Analyze each calibration standard according to Section 10, adding 10 µL of internal standard spiking solution directly to the syringe (Section 10.4). Tabulate peak height or area responses against concentration for each compound and internal standard, and calculate response factors (RF) for each compound using Equation 1.




Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard.

Cs = Concentration of the parameter to be measured.

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.5 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of a QC check sample.


7.5.1 Prepare the QC check sample as described in Section 8.2.2.


7.5.2 Analyze the QC check sample according to Section 10.


7.5.3 For each parameter, compare the response (Q) with the corresponding calibration acceptance criteria found in Table 2. If the responses for all parameters of interest fall within the designated ranges, analysis of actual samples can begin. If any individual Q falls outside the range, proceed according to Section 7.5.4.



Note:

The large number of parameters in Table 2 present a substantial probability that one or more will not meet the calibration acceptance criteria when all parameters are analyzed.


7.5.4 Repeat the test only for those parameters that failed to meet the calibration acceptance criteria. If the response for a parameter does not fall within the range in this second test, a new calibration curve, calibration factor, or RF must be prepared for that parameter according to Section 7.3 or 7.4.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Section 10.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Each day, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system are under control.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 10 µg/mL in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Prepare a QC check sample to contain 20 µg/L of each parameter by adding 200 µL of QC check sample concentrate to 100 mL of reagent water.


8.2.3 Analyze four 5-mL aliquots of the well-mixed QC check sample according to Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter of interest using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, then the system performance is unacceptable for that parameter.



Note:

The large number of parameters in Table 2 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.


8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.


8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.3.


8.2.6.2 Beginning with Section 8.2.3, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.3.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 20 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.2 Analyze one 5-mL sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second 5-mL sample aliquot with 10 µL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7 If spiking was performed at a concentration lower than 20 µg/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory. If the entire list of parameters in Table 2 must be measured in the sample in Section 8.3, the probability that the analysis of a QC check standard will be required is high. In this case the QC check standard should be routinely analyzed with the spiked sample.


8.4.1 Prepare the QC check standard by adding 10 µL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 5 mL of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If p
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


8.7 The analyst should monitor both the performance of the analytical system and the effectiveness of the method in dealing with each sample matrix by spiking each sample, standard, and reagent water blank with surrogate halocarbons. A combination of bromochloromethane, 2-bromo-1-chloropropane, and 1,4-dichlorobutane is recommended to encompass the range of the temperature program used in this method. From stock standard solutions prepared as in Section 6.5, add a volume to give 750 µg of each surrogate to 45 mL of reagent water contained in a 50-mL volumetric flask, mix and dilute to volume for a concentration of 15 ng/µL. Add 10 µL of this surrogate spiking solution directly into the 5-mL syringe with every sample and reference standard analyzed. Prepare a fresh surrogate spiking solution on a weekly basis. If the internal standard calibration procedure is being used, the surrogate compounds may be added directly to the internal standard spiking solution (Section 7.4.2).


9. Sample Collection, Preservation, and Handling

9.1 All samples must be iced or refrigerated from the time of collection until analysis. If the sample contains free or combined chlorine, add sodium thiosulfate preservative (10 mg/40 mL is sufficient for up to 5 ppm Cl2) to the empty sample bottle just prior to shipping to the sampling site. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
8 Field test kits are available for this purpose.


9.2 Grab samples must be collected in glass containers having a total volume of at least 25 mL. Fill the sample bottle just to overflowing in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. If preservative has been added, shake vigorously for 1 min. Maintain the hermetic seal on the sample bottle until time of analysis.


9.3 All samples must be analyzed within 14 days of collection.
3


10. Procedure

10.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are estimated retention times and MDL that can be achieved under these conditions. An example of the separations achieved by Column 1 is shown in Figure 5. Other packed columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


10.2 Calibrate the system daily as described in Section 7.


10.3 Adjust the purge gas (nitrogen or helium) flow rate to 40 mL/min. Attach the trap inlet to the purging device, and set the purge and trap system to purge (Figure 3). Open the syringe valve located on the purging device sample introduction needle.


10.4 Allow the sample to come to ambient temperature prior to introducing it to the syringe. Remove the plunger from a 5-mL syringe and attach a closed syringe valve. Open the sample bottle (or standard) and carefully pour the sample into the syringe barrel to just short of overflowing. Replace the syringe plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume to 5.0 mL. Since this process of taking an aliquot destroys the validity of the sample for future analysis, the analyst should fill a second syringe at this time to protect against possible loss of data. Add 10.0 µL of the surrogate spiking solution (Section 8.7) and 10.0 µL of the internal standard spiking solution (Section 7.4.2), if applicable, through the valve bore, then close the valve.


10.5 Attach the syringe-syringe valve assembly to the syringe valve on the purging device. Open the syringe valves and inject the sample into the purging chamber.


10.6 Close both valves and purge the sample for 11.0 ±0.1 min at ambient temperature.


10.7 After the 11-min purge time, attach the trap to the chromatograph, adjust the purge and trap system to the desorb mode (Figure 4), and begin to temperature program the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to 180 °C while backflushing the trap with an inert gas between 20 and 60 mL/min for 4 min. If rapid heating of the trap cannot be achieved, the GC column must be used as a secondary trap by cooling it to 30 °C (subambient temperature, if poor peak geometry or random retention time problems persist) instead of the initial program temperature of 45 °C


10.8 While the trap is being desorbed into the gas chromatograph, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL flushes of reagent water.


10.9 After desorbing the sample for 4 min, recondition the trap by returning the purge and trap system to the purge mode. Wait 15 s then close the syringe valve on the purging device to begin gas flow through the trap. The trap temperature should be maintained at 180 °C After approximately 7 min, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When the trap is cool, the next sample can be analyzed.


10.10 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


10.11 If the response for a peak exceeds the working range of the system, prepare a dilution of the sample with reagent water from the aliquot in the second syringe and reanalyze.


11. Calculations

11.1 Determine the concentration of individual compounds in the sample.


11.1.1 If the external standard calibration procedure is used, calculate the concentration of the parameter being measured from the peak response using the calibration curve or calibration factor determined in Section 7.3.2.


11.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.4.3 and Equation 2.


Equation 2



where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard.

11.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


12. Method Performance

12.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentration listed in Table 1 were obtained using reagent water.
11. Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


12.2 This method is recommended for use in the concentration range from the MDL to 1000 × MDL. Direct aqueous injection techniques should be used to measure concentration levels above 1000 × MDL.


12.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 8.0 to 500 µg/L.
9 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. Bellar, T.A., and Lichtenberg, J.J. “Determining Volatile Organics at Microgram-per-Litre-Levels by Gas Chromatography,” Journal of the American Water Works Association, 66, 739 (1974).


3. Bellar, T.A., and Lichtenberg, J.J. “Semi-Automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds,” Proceedings from Symposium on Measurement of Organic Pollutants in Water and Wastewater, American Society for Testing and Materials, STP 686, C.E. Van Hall, editor, 1978.


4. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


8. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA 600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


9. “EPA Method Study 24, Method 601—Purgeable Halocarbons by the Purge and Trap Method,” EPA 600/4-84-064, National Technical Information Service, PB84-212448, Springfield, Virginia 22161, July 1984.


10. “Method Validation Data for EPA Method 601,” Memorandum from B. Potter, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, November 10, 1983.


11. Bellar, T. A., Unpublished data, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, 1981.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Column 1
Column 2
Chloromethane1.505.280.08
Bromomethane2.177.051.18
Dichlorodifluoromethane2.62nd1.81
Vinyl chloride2.675.280.18
Chloroethane3.338.680.52
Methylene chloride5.2510.10.25
Trichlorofluoromethane7.18ndnd
1,1-Dichloroethene7.937.720.13
1,1-Dichloroethane9.3012.60.07
trans-1,2-Dichloroethene10.19.380.10
Chloroform10.712.10.05
1,2-Dichloroethane11.415.40.03
1,1,1-Trichloroethane12.613.10.03
Carbon tetrachloride13.014.40.12
Bromodichloromethane13.714.60.10
1,2-Dichloropropane14.916.60.04
cis-1,3-Dichloropropene15.216.60.34
Trichloroethene15.813.10.12
Dibromochloromethane16.516.60.09
1,1,2-Trichloroethane16.518.10.02
trans-1,3-Dichloropropene16.518.00.20
2-Chloroethylvinyl ether18.0nd0.13
Bromoform19.219.20.20
1,1,2,2-Tetrachloroethane21.6nd0.03
Tetrachloroethene21.715.00.03
Chlorobenzene24.218.80.25
1,3-Dichlorobenzene34.022.40.32
1,2-Dichlorobenzene34.923.50.15
1,4-Dichlorobenzene35.422.30.24

Column 1 conditions: Carbopack B (60/80 mesh) coated with 1% SP-1000 packed in an 8 ft × 0.1 in. ID stainless steel or glass column with helium carrier gas at 40 mL/min flow rate. Column temperature held at 45 °C for 3 min then programmed at 8 °C/min to 220 °C and held for 15 min.

Column 2 conditions: Porisil-C (100/120 mesh) coated with n-octane packed in a 6 ft × 0.1 in. ID stainless steel or glass column with helium carrier gas at 40 mL/min flow rate. Column temperature held at 50 °C for 3 min then programmed at 6 °C/min to 170 °C and held for 4 min.

nd = not determined.


Table 2—Calibration and QC Acceptance Criteria—Method 601
a

Parameter
Range for Q (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range P, Ps (%)
Bromodichloromethane15.2-24.84.310.7-32.042-172
Bromoform14.7-25.34.75.0-29.313-159
Bromomethane11.7-28.37.63.4-24.5D-144
Carbon tetrachloride13.7-26.35.611.8-25.343-143
Chlorobenzene14.4-25.65.010.2-27.438-150
Chloroethane15.4-24.64.411.3-25.246-137
2-Chloroethylvinyl ether12.0-28.08.34.5-35.514-186
Chloroform15.0-25.04.512.4-24.049-133
Chloromethane11.9-28.17.4D-34.9D-193
Dibromochloromethane13.1-26.96.37.9-35.124-191
1,2-Dichlorobenzene14.0-26.05.51.7-38.9D-208
1,3-Dichlorobenzene9.9-30.19.16.2-32.67-187
1,4-Dichlorobenzene13.9-26.15.511.5-25.542-143
1,1-Dichloroethane16.8-23.23.211.2-24.647-132
1,2-Dichloroethane14.3-25.75.213.0-26.551-147
1,1-Dichloroethene12.6-27.46.610.2-27.328-167
trans-1,2-Dichloroethene12.8-27.26.411.4-27.138-155
1,2-Dichloropropane14.8-25.25.210.1-29.944-156
cis-1,3-Dichloropropene12.8-27.27.36.2-33.822-178
trans-1,3-Dichloropropene12.8-27.27.36.2-33.822-178
Methylene chloride15.5-24.54.07.0-27.625-162
1,1,2,2-Tetrachloroethane9.8-30.29.26.6-31.88-184
Tetrachloroethene14.0-26.05.48.1-29.626-162
1,1,1-Trichloroethane14.2-25.84.910.8-24.841-138
1,1,2-Trichloroethane15.7-24.33.99.6-25.439-136
Trichloroethene15.4-24.64.29.2-26.635-146
Trichlorofluoromethane13.3-26.76.07.4-28.121-156
Vinyl chloride13.7-26.35.78.2-29.928-163


a Criteria were calculated assuming a QC check sample concentration of 20 µg/L.

Q = Concentration measured in QC check sample, in µg/L (Section 7.5.3).

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 601

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
Bromodichloromethane1.12C−1.020.11X
+ 0.04		0.20X
+ 1.00
Bromoform0.96C−2.050.12X
+ 0.58		0.21X
+ 2.41
Bromomethane0.76C−1.270.28X
+ 0.27		0.36X
+ 0.94
Carbon tetrachloride0.98C−1.040.15X
+ 0.38		0.20X
+ 0.39
Chlorobenzene1.00C−1.230.15X
−0.02		0.18X
+ 1.21
Choroethane0.99C−1.530.14X
−0.13		0.17X
+ 0.63
2-Chloroethylvinyl ether
a 		1.00C0.20X
0.35X

Chloroform0.93C−0.390.13X
+ 0.15		0.19X
−0.02
Chloromethane0.77C + 0.180.28X
−0.31		0.52X
+ 1.31
Dibromochloromethane0.94C + 2.720.11X
+ 1.10		0.24X
+ 1.68
1,2-Dichlorobenzene0.93C + 1.700.20X
+ 0.97		0.13X
+ 6.13
1,3-Dichlorobenzene0.95C + 0.430.14X
+ 2.33		0.26X
+ 2.34
1,4-Dichlorobenzene0.93C−0.090.15X
+ 0.29		0.20X
+ 0.41
1,1-Dichloroethane0.95C−1.080.09X
+ 0.17		0.14X
+ 0.94
1,2-Dichloroethane1.04C−1.060.11X
+ 0.70		0.15X
+ 0.94
1,1-Dichloroethene0.98C−0.870.21X
−0.23		0.29X
−0.40
trans-1,2-Dichloroethene0.97C−0.160.11X
+ 1.46		0.17X
+ 1.46
1,2-Dichloropropane
a 		1.00C0.13X
0.23X

cis-1,3-Dichloropropene
a 		1.00C0.18X
0.32X

trans-1,3-Dichloropropene
a 		1.00C0.18X
0.32X

Methylene chloride0.91C−0.930.11X
+ 0.33		0.21X
+ 1.43
1,1,2,2-Tetrachloroethene0.95C + 0.190.14X
+ 2.41		0.23X
+ 2.79
Tetrachloroethene0.94C + 0.060.14X
+ 0.38		0.18X
+ 2.21
1,1,1-Trichloroethane0.90C−0.160.15X
+ 0.04		0.20X
+ 0.37
1,1,2-Trichloroethane0.86C + 0.300.13X
−0.14		0.19X
+ 0.67
Trichloroethene0.87C + 0.480.13X
−0.03		0.23X
+ 0.30
Trichlorofluoromethane0.89C−0.070.15X
+ 0.67		0.26X
+ 0.91
Vinyl chloride0.97C−0.360.13X
+ 0.65		0.27X
+ 0.40

X
′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sn′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S
1 = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.


a Estimates based upon the performance in a single laboratory.
10






Method 602—Purgeable Aromatics

1. Scope and Application

1.1 This method covers the determination of various purgeable aromatics. The following parameters may be determined by this method:


Parameter
STORET No.
CAS No.
Benzene3403071-43-2
Chlorobenzene34301108-90-7
1,2-Dichlorobenzene3453695-50-1
1,3-Dichlorobenzene34566541-73-1
1,4-Dichlorobenzene34571106-46-7
Ethylbenzene34371100-41-4
Toluene34010108-88-3

1.2 This is a purge and trap gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 624 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above.


1.3 The method detection limit (MDL, defined in Section 12.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.5 This method is restricted to use by or under the supervision of analysts experienced in the operation of a purge and trap system and a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 An inert gas is bubbled through a 5-mL water sample contained in a specially-designed purging chamber at ambient temperature. The aromatics are efficiently transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the aromatics are trapped. After purging is completed, the trap is heated and backflushed with the inert gas to desorb the aromatics onto a gas chromatographic column. The gas chromatograph is temperature programmed to separate the aromatics which are then detected with a photoionization detector.
2 3


2.2 The method provides an optional gas chromatographic column that may be helpful in resolving the compounds of interest from interferences that may occur.


3. Interferences

3.1 Impurities in the purge gas and organic compounds outgassing from the plumbing ahead of the trap account for the majority of contamination problems. The analytical system must be demonstrated to be free from contamination under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3. The use of non-Teflon plastic tubing, non-Teflon thread sealants, or flow controllers with rubber components in the purge and trap system should be avoided.


3.2 Samples can be contaminated by diffusion of volatile organics through the septum seal into the sample during shipment and storage. A field reagent blank prepared from reagent water and carried through the sampling and handling protocol can serve as a check on such contamination.


3.3 Contamination by carry-over can occur whenever high level and low level samples are sequentially analyzed. To reduce carry-over, the purging device and sample syringe must be rinsed with reagent water between sample analyses. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of reagent water to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high aromatic levels, it may be necessary to wash the purging device with a detergent solution, rinse it with distilled water, and then dry it in an oven at 105 °C between analyses. The trap and other parts of the system are also subject to contamination; therefore, frequent bakeout and purging of the entire system may be required.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4 6 for the information of the analyst.


4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: benzene and 1,4-dichlorobenzene. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete sampling.


5.1.1 Vial]25-mL capacity or larger, equipped with a screw cap with a hole in the center (Pierce #13075 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 °C before use.


5.1.2 Septum—Teflon-faced silicone (Pierce #12722 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 °C for 1 h before use.


5.2 Purge and trap system—The purge and trap system consists of three separate pieces of equipment: A purging device, trap, and desorber. Several complete systems are now commercially available.


5.2.1 The purging device must be designed to accept 5-mL samples with a water column at least 3 cm deep. The gaseous head space between the water column and the trap must have a total volume of less than 15 mL. The purge gas must pass through the water column as finely divided bubbles with a diameter of less than 3 mm at the origin. The purge gas must be introduced no more than 5 mm from the base of the water column. The purging device illustrated in Figure 1 meets these design criteria.


5.2.2 The trap must be at least 25 cm long and have an inside diameter of at least 0.105 in.


5.2.2.1 The trap is packed with 1 cm of methyl silicone coated packing (Section 6.4.2) and 23 cm of 2,6-diphenylene oxide polymer (Section 6.4.1) as shown in Figure 2. This trap was used to develop the method performance statements in Section 12.


5.2.2.2 Alternatively, either of the two traps described in Method 601 may be used, although water vapor will preclude the measurement of low concentrations of benzene.


5.2.3 The desorber must be capable of rapidly heating the trap to 180 °C. The polymer section of the trap should not be heated higher than 180 °C and the remaining sections should not exceed 200 °C. The desorber illustrated in Figure 2 meets these design criteria.


5.2.4 The purge and trap system may be assembled as a separate unit or be coupled to a gas chromatograph as illustrated in Figures 3, 4, and 5.


5.3 Gas chromatograph—An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.3.1 Column 1—6 ft long × 0.082 in. ID stainless steel or glass, packed with 5% SP-1200 and 1.75% Bentone-34 on Supelcoport (100/120 mesh) or equivalent. This column was used to develop the method performance statements in Section 12. Guidelines for the use of alternate column packings are provided in Section 10.1.


5.3.2 Column 2—8 ft long × 0.1 in ID stainless steel or glass, packed with 5% 1,2,3-Tris(2-cyanoethoxy)propane on Chromosorb W-AW (60/80 mesh) or equivalent.


5.3.3 Detector—Photoionization detector (h-Nu Systems, Inc. Model PI-51-02 or equivalent). This type of detector has been proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 12. Guidelines for the use of alternate detectors are provided in Section 10.1.


5.4 Syringes—5-mL glass hypodermic with Luerlok tip (two each), if applicable to the purging device.


5.5 Micro syringes—25-µL, 0.006 in. ID needle.


5.6 Syringe valve—2-way, with Luer ends (three each).


5.7 Bottle—15-mL, screw-cap, with Teflon cap liner.


5.8 Balance—Analytical, capable of accurately weighing 0.0001 g.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.1.1 Reagent water can be generated by passing tap water through a carbon filter bed containing about 1 lb of activated carbon (Filtrasorb-300, Calgon Corp., or equivalent).


6.1.2 A water purification system (Millipore Super-Q or equivalent) may be used to generate reagent water.


6.1.3 Reagent water may also be prepared by boiling water for 15 min. Subsequently, while maintaining the temperature at 90 °C, bubble a contaminant-free inert gas through the water for 1 h. While still hot, transfer the water to a narrow mouth screw-cap bottle and seal with a Teflon-lined septum and cap.


6.2 Sodium thiosulfate—(ACS) Granular.


6.3 Hydrochloric acid (1 + 1)—Add 50 mL of concentrated HCl (ACS) to 50 mL of reagent water.


6.4 Trap Materials:


6.4.1 2,6-Diphenylene oxide polymer—Tenax, (60/80 mesh), chromatographic grade or equivalent.


6.4.2 Methyl silicone packing—3% OV-1 on Chromosorb-W (60/80 mesh) or equivalent.


6.5 Methanol—Pesticide quality or equivalent.


6.6 Stock standard solutions—Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standard solutions in methanol using assayed liquids. Because of the toxicity of benzene and 1,4-dichlorobenzene, primary dilutions of these materials should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be used when the analyst handles high concentrations of such materials.


6.6.1 Place about 9.8 mL of methanol into a 10-mL ground glass stoppered volumetric flask. Allow the flask to stand, unstoppered, for about 10 min or until all alcohol wetted surfaces have dried. Weigh the flask to the nearest 0.1 mg.


6.6.2 Using a 100-µL syringe, immediately add two or more drops of assayed reference material to the flask, then reweigh. Be sure that the drops fall directly into the alcohol without contacting the neck of the flask.


6.6.3 Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in µg/µL from the net gain in weight. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.6.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store at 4 °C and protect from light.


6.6.5 All standards must be replaced after one month, or sooner if comparison with check standards indicates a problem.


6.7 Secondary dilution standards—Using stock standard solutions, prepare secondary dilution standards in methanol that contain the compounds of interest, either singly or mixed together. The secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in Section 7.3.1 or 7.4.1 will bracket the working range of the analytical system. Secondary solution standards must be stored with zero headspace and should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.8 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Assemble a purge and trap system that meets the specifications in Section 5.2. Condition the trap overnight at 180 °C by backflushing with an inert gas flow of at least 20 mL/min. Condition the trap for 10 min once daily prior to use.


7.2 Connect the purge and trap system to a gas chromatograph. The gas chromatograph must be operated using temperature and flow rate conditions equivalent to those given in Table 1. Calibrate the purge and trap-gas chromatographic system using either the external standard technique (Section 7.3) or the internal standard technique (Section 7.4).


7.3 External standard calibration procedure:


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter by carefully adding 20.0 µL of one or more secondary dilution standards to 100, 500, or 1000 mL of reagent water. A 25-µL syringe with a 0.006 in. ID needle should be used for this operation. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector. These aqueous standards must be prepared fresh daily.


7.3.2 Analyze each calibration standard according to Section 10, and tabulate peak height or area responses versus the concentration in the standard. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to concentration (calibration factor) is a constant over the working range (

7.4 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples. The compound, α,α,α,-trifluorotoluene, recommended as a surrogate spiking compound in Section 8.7 has been used successfully as an internal standard.


7.4.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest as described in Section 7.3.1.


7.4.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 6.6 and 6.7. It is recommended that the secondary dilution standard be prepared at a concentration of 15 µg/mL of each internal standard compound. The addition of 10 µl of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30 µg/L.


7.4.3 Analyze each calibration standard according to Section 10, adding 10 µL of internal standard spiking solution directly to the syringe (Section 10.4). Tabulate peak height or area responses against concentration for each compound and internal standard, and calculate response factors (RF) for each compound using Equation 1.


RF = (As)(Cis (Ais)(Cs)

Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard

Cs = Concentration of the parameter to be measured.

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.5 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of a QC check sample.


7.5.1 Prepare the QC check sample as described in Section 8.2.2.


7.5.2 Analyze the QC check sample according to Section 10.


7.5.3 For each parameter, compare the response (Q) with the corresponding calibration acceptance criteria found in Table 2. If the responses for all parameters of interest fall within the designated ranges, analysis of actual samples can begin. If any individual Q falls outside the range, a new calibration curve, calibration factor, or RF must be prepared for that parameter according to Section 7.3 or 7.4.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Section 10.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Each day, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system are under control.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 10 µg/mL in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Prepare a QC check sample to contain 20 µg/L of each parameter by adding 200 µL of QC check sample concentrate to 100 mL of reagant water.


8.2.3 Analyze four 5-mL aliquots of the well-mixed QC check sample according to Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter of interest using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter.



Note:

The large number of parameters in Table 2 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.


8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.


8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.3.


8.2.6.2 Beginning with Section 8.2.3, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.3.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 20 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.2 Analyze one 5-mL sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second 5-mL sample aliquot with 10 µL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7 If spiking was performed at a concentration lower than 20 µg/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T) ±2.44(100 S′/T)%.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 10 µL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 5 mL of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


8.7 The analyst should monitor both the performance of the analytical system and the effectiveness of the method in dealing with each sample matrix by spiking each sample, standard, and reagent water blank with surrogate compounds (e.g. α, α, α,-trifluorotoluene) that encompass the range of the temperature program used in this method. From stock standard solutions prepared as in Section 6.6, add a volume to give 750 µg of each surrogate to 45 mL of reagent water contained in a 50-mL volumetric flask, mix and dilute to volume for a concentration of 15 mg/µL. Add 10 µL of this surrogate spiking solution directly into the 5-mL syringe with every sample and reference standard analyzed. Prepare a fresh surrogate spiking solution on a weekly basis. If the internal standard calibration procedure is being used, the surrogate compounds may be added directly to the internal standard spiking solution (Section 7.4.2).


9. Sample Collection, Preservation, and Handling

9.1 The samples must be iced or refrigerated from the time of collection until analysis. If the sample contains free or combined chlorine, add sodium thiosulfate preservative (10 mg/40 mL is sufficient for up to 5 ppm Cl2) to the empty sample bottle just prior to shipping to the sampling site. EPA Method 330.4 or 330.5 may be used for measurement of residual chlorine.
8 Field test kits are available for this purpose.


9.2 Collect about 500 mL of sample in a clean container. Adjust the pH of the sample to about 2 by adding 1 + 1 HCl while stirring. Fill the sample bottle in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. Maintain the hermetic seal on the sample bottle until time of analysis.


9.3 All samples must be analyzed within 14 days of collection.
3


10. Procedure

10.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are estimated retention times and MDL that can be achieved under these conditions. An example of the separations achieved by Column 1 is shown in Figure 6. Other packed columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


10.2 Calibrate the system daily as described in Section 7.


10.3 Adjust the purge gas (nitrogen or helium) flow rate to 40 mL/min. Attach the trap inlet to the purging device, and set the purge and trap system to purge (Figure 3). Open the syringe valve located on the purging device sample introduction needle.


10.4 Allow the sample to come to ambient temperature prior to introducing it to the syringe. Remove the plunger from a 5-mL syringe and attach a closed syringe valve. Open the sample bottle (or standard) and carefully pour the sample into the syringe barrel to just short of overflowing. Replace the syringe plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume to 5.0 mL. Since this process of taking an aliquot destroys the validity of the sample for future analysis, the analyst should fill a second syringe at this time to protect against possible loss of data. Add 10.0 µL of the surrogate spiking solution (Section 8.7) and 10.0 µL of the internal standard spiking solution (Section 7.4.2), if applicable, through the valve bore, then close the valve.


10.5 Attach the syringe-syringe valve assembly to the syringe valve on the purging device. Open the syringe valves and inject the sample into the purging chamber.


10.6 Close both valves and purge the sample for 12.0 ±0.1 min at ambient temperature.


10.7 After the 12-min purge time, disconnect the purging device from the trap. Dry the trap by maintaining a flow of 40 mL/min of dry purge gas through it for 6 min (Figure 4). If the purging device has no provision for bypassing the purger for this step, a dry purger should be inserted into the device to minimize moisture in the gas. Attach the trap to the chromatograph, adjust the purge and trap system to the desorb mode (Figure 5), and begin to temperature program the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to 180 °C while backflushing the trap with an inert gas between 20 and 60 mL/min for 4 min. If rapid heating of the trap cannot be achieved, the GC column must be used as a secondary trap by cooling it to 30 °C (subambient temperature, if poor peak geometry and random retention time problems persist) instead of the initial program temperature of 50 °C.


10.8 While the trap is being desorbed into the gas chromatograph column, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL flushes of reagent water.


10.9 After desorbing the sample for 4 min, recondition the trap by returning the purge and trap system to the purge mode. Wait 15 s, then close the syringe valve on the purging device to begin gas flow through the trap. The trap temperature should be maintained at 180 °C. After approximately 7 min, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When the trap is cool, the next sample can be analyzed.


10.10 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


10.11 If the response for a peak exceeds the working range of the system, prepare a dilution of the sample with reagent water from the aliquot in the second syringe and reanalyze.


11. Calculations

11.1 Determine the concentration of individual compounds in the sample.


11.1.1 If the external standard calibration procedure is used, calculate the concentration of the parameter being measured from the peak response using the calibration curve or calibration factor determined in Section 7.3.2.


11.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.4.3 and Equation 2.




Equation 2


where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard.

11.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


12. Method Performance

12.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
9 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


12.2 This method has been demonstrated to be applicable for the concentration range from the MDL to 100 × MDL.
9 Direct aqueous injection techniques should be used to measure concentration levels above 1000 × MDL.


12.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 2.1 to 550 µg/L.
9 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. Lichtenberg, J.J. “Determining Volatile Organics at Microgram-per-Litre-Levels by Gas Chromatography,” Journal American Water Works Association, 66, 739 (1974).


3. Bellar, T.A., and Lichtenberg, J.J. “Semi-Automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds,” Proceedings of Symposium on Measurement of Organic Pollutants in Water and Wastewater. American Society for Testing and Materials, STP 686, C.E. Van Hall, editor, 1978.


4. “Carcinogens—Working with Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health. Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3. is two times the value 1.22 derived in this report.)


8.“Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Office of Research and Development, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268. March 1979.


9. “EPA Method Study 25, Method 602, Purgeable Aromatics,” EPA 600/4-84-042, National Technical Information Service, PB84-196682, Springfield, Virginia 22161, May 1984.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Column 1
Column 2
Benzene3.332.750.2
Toluene5.754.250.2
Ethylbenzene8.256.250.2
Chlorobenzene9.178.020.2
1,4-Dichlorobenzene16.816.20.3
1,3-Dichlorobenzene18.215.00.4
1,2-Dichlorobenzene25.919.40.4

Column 1 conditions: Supelcoport (100/120 mesh) coated with 5% SP-1200/1.75% Bentone-34 packed in a 6 ft × 0.085 in. ID stainless steel column with helium carrier gas at 36 mL/min flow rate. Column temperature held at 50 °C for 2 min then programmed at 6 °C/min to 90 °C for a final hold.

Column 2 conditions: Chromosorb W-AW (60/80 mesh) coated with 5% 1,2,3-Tris(2-cyanoethyoxy)propane packed in a 6 ft × 0.085 in. ID stainless steel column with helium carrier gas at 30 mL/min flow rate. Column temperature held at 40 °C for 2 min then programmed at 2 °C/min to 100 °C for a final hold.


Table 2—Calibration and QC Acceptance Criteria—Method 602
a

Parameter
Range for Q (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps(%)
Benzene15.4-24.64.110.0-27.939-150
Chlorobenzene16.1-23.93.512.7-25.455-135
1,2-Dichlorobenzene13.6-26.45.810.6-27.637-154
1,3-Dichlorobenzene14.5-25.55.012.8-25.550-141
1,4-Dichlorobenzene13.9-26.15.511.6-25.542-143
Ethylbenzene12.6-27.46.710.0-28.232-160
Toluene15.5-24.54.011.2-27.746-148

Q = Concentration measured in QC check sample, in µg/L (Section 7.5.3).

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

Ps, P = Percent recovery measured (Section 8.3.2, Section 8.4.2).


a Criteria were calculated assuming a QC check sample concentration of 20 µg/L.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 602

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, s′ (µg/L)
Overall precision, S′ (µg/L)
Benzene0.92C + 0.570.09X
+ 0.59		0.21X
+ 0.56
Chlorobenzene0.95C + 0.020.09X
+ 0.23		0.17X
+ 0.10
1,2-Dichlorobenzene0.93C + 0.520.17X
−0.04		0.22X
+ 0.53
1,3-Dichlorobenzene0.96C−0.050.15X
−0.10		0.19X
+ 0.09
1,4-Dichlorobenzene0.93C−0.090.15X
+ 0.28		0.20X
+ 0.41
Ethylbenzene0.94C + 0.310.17X
+ 0.46		0.26X
+ 0.23
Toluene0.94C + 0.650.09X
+ 0.48		0.18X
+ 0.71

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

S′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in X µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the Concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.






Method 603—Acrolein and Acrylonitrile

1. Scope and Application

1.1 This method covers the determination of acrolein and acrylonitrile. The following parameters may be determined by this method:


Parameter
STORET No.
CAS No.
Acrolein34210107-02-8
Acrylonitrile34215107-13-1


1.2 This is a purge and trap gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for either or both of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 624 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for the parameters listed above, if used with the purge and trap conditions described in this method.


1.3 The method detection limit (MDL, defined in Section 12.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.5 This method is restricted to use by or under the supervision of analysts experienced in the operation of a purge and trap system and a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 An inert gas is bubbled through a 5-mL water sample contained in a heated purging chamber. Acrolein and acrylonitrile are transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the analytes are trapped. After the purge is completed, the trap is heated and backflushed with the inert gas to desorb the compound onto a gas chromatographic column. The gas chromatograph is temperature programmed to separate the analytes which are then detected with a flame ionization detector.
2 3


2.2 The method provides an optional gas chromatographic column that may be helpful in resolving the compounds of interest from the interferences that may occur.


3. Interferences

3.1 Impurities in the purge gas and organic compound outgassing from the plumbing of the trap account for the majority of contamination problems. The analytical system must be demonstrated to be free from contamination under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3. The use of non-Teflon plastic tubing, non-Teflon thread sealants, or flow controllers with rubber components in the purge and trap system should be avoided.


3.2 Samples can be contaminated by diffusion of volatile organics through the septum seal into the sample during shipment and storage. A field reagent blank prepared from reagent water and carried through the sampling and handling protocol can serve as a check on such contamination.


3.3 Contamination by carry-over can occur whenever high level and low level samples are sequentially analyzed. To reduce carry-over, the purging device and sample syringe must be rinsed between samples with reagent water. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of reagent water to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high analyte levels, it may be necessary to wash the purging device with a detergent solution, rinse it with distilled water, and then dry it in an oven at 105 °C between analyses. The trap and other parts of the system are also subject to contamination, therefore, frequent bakeout and purging of the entire system may be required.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this view point, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4 6 for the information of the analyst.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete sampling.


5.1.1 Vial—25-mL capacity or larger, equipped with a screw cap with a hole in the center (Pierce #13075 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 °C before use.


5.1.2 Septum—Teflon-faced silicone (Pierce #12722 or equivalent). Detergent wash, rinse with tap and distilled water and dry at 105 °C for 1 h before use.


5.2 Purge and trap system—The purge and trap system consists of three separate pieces of equipment: a purging device, trap, and desorber. Several complete systems are now commercially available.


5.2.1 The purging device must be designed to accept 5-mL, samples with a water column at least 3 cm deep. The gaseous head space between the water column and the trap must have a total volume of less than 15 mL. The purge gas must pass through the water column as finely divided bubbles with a diameter of less than 3 mm at the origin. The purge gas must be introduced no more than 5 mm from the base of the water column. The purging device must be capable of being heated to 85 °C within 3.0 min after transfer of the sample to the purging device and being held at 85 ±2 °C during the purge cycle. The entire water column in the purging device must be heated. Design of this modification to the standard purging device is optional, however, use of a water bath is suggested.


5.2.1.1 Heating mantle—To be used to heat water bath.


5.2.1.2 Temperature controller—Equipped with thermocouple/sensor to accurately control water bath temperature to ±2 °C. The purging device illustrated in Figure 1 meets these design criteria.


5.2.2 The trap must be at least 25 cm long and have an inside diameter of at least 0.105 in. The trap must be packed to contain 1.0 cm of methyl silicone coated packing (Section 6.5.2) and 23 cm of 2,6-diphenylene oxide polymer (Section 6.5.1). The minimum specifications for the trap are illustrated in Figure 2.


5.2.3 The desorber must be capable of rapidly heating the trap to 180 °C, The desorber illustrated in Figure 2 meets these design criteria.


5.2.4 The purge and trap system may be assembled as a separate unit as illustrated in Figure 3 or be coupled to a gas chromatograph.


5.3 pH paper—Narrow pH range, about 3.5 to 5.5 (Fisher Scientific Short Range Alkacid No. 2, #14-837-2 or equivalent).


5.4 Gas chromatograph—An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.4.1 Column 1—10 ft long × 2 mm ID glass or stainless steel, packed with Porapak-QS (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 12. Guidelines for the use of alternate column packings are provided in Section 10.1.


5.4.2 Column 2—6 ft long × 0.1 in. ID glass or stainless steel, packed with Chromosorb 101 (60/80 mesh) or equivalent.


5.4.3 Detector—Flame ionization detector. This type of detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 12. Guidelines for the use of alternate detectors are provided in Section 10.1.


5.5 Syringes—5-mL, glass hypodermic with Luerlok tip (two each).


5.6 Micro syringes—25-µL, 0.006 in. ID needle.


5.7 Syringe valve—2-way, with Luer ends (three each).


5.8 Bottle—15-mL, screw-cap, with Teflon cap liner.


5.9 Balance—Analytical, capable of accurately weighing 0.0001 g.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.1.1 Reagent water can be generated by passing tap water through a carbon filter bed containing about 1 lb of activated carbon (Filtrasorb-300, Calgon Corp., or equivalent).


6.1.2 A water purification system (Millipore Super-Q or equivalent) may be used to generate reagent water.


6.1.3 Regent water may also be prepared by boiling water for 15 min. Subsequently, while maintaining the temperature at 90 °C, bubble a contaminant-free inert gas through the water for 1 h. While still hot, transfer the water to a narrow mouth screw-cap bottle and seal with a Teflon-lined septum and cap.


6.2 Sodium thiosulfate—(ACS) Granular.


6.3 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.4 Hydrochloric acid (1 + 1)—Slowly, add 50 mL of concentrated HCl (ACS) to 50 mL of reagent water.


6.5 Trap Materials:


6.5.1 2,6-Diphenylene oxide polymer—Tenax (60/80 mesh), chromatographic grade or equivalent.


6.5.2 Methyl silicone packing—3% OV-1 on Chromosorb-W (60/80 mesh) or equivalent.


6.6 Stock standard solutions—Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standard solutions in reagent water using assayed liquids. Since acrolein and acrylonitrile are lachrymators, primary dilutions of these compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be used when the analyst handles high concentrations of such materials.


6.6.1 Place about 9.8 mL of reagent water into a 10-mL ground glass stoppered volumetric flask. For acrolein standards the reagent water must be adjusted to pH 4 to 5. Weight the flask to the nearest 0.1 mg.


6.6.2 Using a 100-µL syringe, immediately add two or more drops of assayed reference material to the flask, then reweigh. Be sure that the drops fall directly into the water without contacting the neck of the flask.


6.6.3 Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in µg/µL from the net gain in weight. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock staldard. Optionally, stock standard solutions may be prepared using the pure standard material by volumetrically measuring the appropriate amounts and determining the weight of the material using the density of the material. Commercially prepared stock standards may be used at any concentration if they are certified by the manufactaurer or by an independent source.


6.6.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store at 4 °C and protect from light.


6.6.5 Prepare fresh standards daily.


6.7 Secondary dilution standards—Using stock standard solutions, prepare secondary dilution standards in reagent water that contain the compounds of interest, either singly or mixed together. The secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in Section 7.3.1 or 7.4.1 will bracket the working range of the analytical system. Secondary dilution standards should be prepared daily and stored at 4 °C.


6.8 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Assemble a purge and trap system that meets the specifications in Section 5.2. Condition the trap overnight at 180 °C by backflushing with an inert gas flow of at least 20 mL/min. Condition the trap for 10 min once daily prior to use.


7.2 Connect the purge and trap system to a gas chromatograph. The gas chromatograph must be operated using temperature and flow rate conditions equivalent to those given in Table 1. Calibrate the purge and trap-gas chromatographic system using either the external standard technique (Section 7.3) or the internal standard technique (Section 7.4).


7.3 External standard calibration procedure:


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter by carefully adding 20.0 µL of one or more secondary dilution standards to 100, 500, or 1000 mL of reagent water. A 25-µL syringe with a 0.006 in. ID needle should be used for this operation. One of the external standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector. These standards must be prepared fresh daily.


7.3.2 Analyze each calibration standard according to Section 10, and tabulate peak height or area responses versus the concentration of the standard. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to concentration (calibration factor) is a constant over the working range (

7.4 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.4.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest as described in Section 7.3.1.


7.4.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 6.6 and 6.7. It is recommended that the secondary dilution standard be prepared at a concentration of 15 µg/mL of each internal standard compound. The addition of 10 µL of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30 µg/L.


7.4.3 Analyze each calibration standard according to Section 10, adding 10 µL of internal standard spiking solution directly to the syringe (Section 10.4). Tabulate peak height or area responses against concentration for each compound and internal standard, and calculate response factors (RF) for each compound using Equation 1.


RF = (As)(Cis (Ais)(Cs)

Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard.

Cs = Concentration of the parameter to be measured.

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.5 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of a QC check sample.


7.5.1 Prepare the QC check sample as described in Section 8.2.2.


7.5.2 Analyze the QC check sample according to Section 10.


7.5.3 For each parameter, compare the response (Q) with the corresponding calibration acceptance criteria found in Table 2. If the responses for all parameters of interest fall within the designated ranges, analysis of actual samples can begin. If any individual Q falls outside the range, a new calibration curve, calibration factor, or RF must be prepared for that parameter according to Section 7.3 or 7.4.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Section 10.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Each day, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system are under control.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 25 µg/mL in reagent water. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Prepare a QC check sample to contain 50 µg/L of each parameter by adding 200 µL of QC check sample concentrate to 100 mL of reagent water.


8.2.3 Analyze four 5-mL aliquots of the well-mixed QC check sample according to Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 3. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If either s exceeds the precision limit or X
falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for each compound of interest.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 50 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.2 Analyze one 5-mL sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second 5-mL sample aliquot with 10 µL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 3. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 10 µL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 5 mL of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 3. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 All samples must be iced or refrigerated from the time of collection until analysis. If the sample contains free or combined chlorine, add sodium thiosulfate preservative (10 mg/40 mL is sufficient for up to 5 ppm Cl2) to the empty sample bottle just prior to shipping to the sampling site. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
8 Field test kits are available for this purpose.


9.2 If acrolein is to be analyzed, collect about 500 mL of sample in a clean glass container. Adjust the pH of the sample to 4 to 5 using acid or base, measuring with narrow range pH paper. Samples for acrolein analysis receiving no pH adjustment must be analyzed within 3 days of sampling.


9.3 Grab samples must be collected in glass containers having a total volume of at least 25 mL. Fill the sample bottle just to overflowing in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. If preservative has been added, shake vigorously for 1 min. Maintain the hermetic seal on the sample bottle until time of analysis.


9.4 All samples must be analyzed within 14 days of collection.
3


10. Procedure

10.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are estimated retention times and MDL that can be achieved under these conditions. An example of the separations achieved by Column 1 is shown in Figure 5. Other packed columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


10.2 Calibrate the system daily as described in Section 7.


10.3 Adjust the purge gas (nitrogen or helium) flow rate to 20 mL-min. Attach the trap inlet to the purging device, and set the purge and trap system to purge (Figure 3). Open the syringe valve located on the purging device sample introduction needle.


10.4 Remove the plunger from a 5-mL syringe and attach a closed syringe valve. Open the sample bottle (or standard) and carefully pour the sample into the syringe barrel to just short of overflowing. Replace the syringe plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume to 5.0 mL. Since this process of taking an aliquot destroys the validity of the sample for future analysis, the analyst should fill a second syringe at this time to protect against possible loss of data. Add 10.0 µL of the internal standard spiking solution (Section 7.4.2), if applicable, through the valve bore then close the valve.


10.5 Attach the syringe-syringe valve assembly to the syringe valve on the purging device. Open the syringe valves and inject the sample into the purging chamber.


10.6 Close both valves and purge the sample for 15.0 ±0.1 min while heating at 85 ±2 °C.


10.7 After the 15-min purge time, attach the trap to the chromatograph, adjust the purge and trap system to the desorb mode (Figure 4), and begin to temperature program the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to 180 °C while backflushing the trap with an inert gas between 20 and 60 mL/min for 1.5 min.


10.8 While the trap is being desorbed into the gas chromatograph, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL flushes of reagent water.


10.9 After desorbing the sample for 1.5 min, recondition the trap by returning the purge and trap system to the purge mode. Wait 15 s then close the syringe valve on the purging device to begin gas flow through the trap. The trap temperature should be maintained at 210 °C. After approximately 7 min, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When the trap is cool, the next sample can be analyzed.


10.10 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


11. Calculations

11.1 Determine the concentration of individual compounds in the sample.


11.1.1 If the external standard calibration procedure is used, calculate the concentration of the parameter being measured from the peak response using the calibration curve or calibration factor determined in Section 7.3.2.


11.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.4.3 and Equation 2.




Equation 2

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard.

11.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


12. Method Performance

12.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
9 The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


12.2 This method is recommended for the concentration range from the MDL to 1,000 × MDL. Direct aqueous injection techniques should be used to measure concentration levels above 1,000 × MDL.


12.3 In a single laboratory (Battelle-Columbus), the average recoveries and standard deviations presented in Table 2 were obtained.
9 Seven replicate samples were analyzed at each spike level.


References

1. 40 CFR part 136, appendix B.


2. Bellar, T.A., and Lichtenberg, J.J. “Determining Volatile Organics at Microgram-per-Litre-Levels by Gas Chromatography,” Journal American Water Works Association, 66, 739 (1974).


3. “Evaluate Test Procedures for Acrolein and Acrylonitrile,” Special letter report for EPA Project 4719-A, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, 27 June 1979.


4. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983).


8. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


9. “Evaluation of Method 603 (Modified),” EPA-600/4-84-ABC, National Technical Information Service, PB84-, Springfield, Virginia 22161, Nov. 1984.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Column 1
Column 2
Acrolein10.68.20.7
Acrylonitrile12.79.80.5

Column 1 conditions: Porapak-QS (80/100 mesh) packed in a 10 ft × 2 mm ID glass or stainless steel column with helium carrier gas at 30 mL/min flow rate. Column temperature held isothermal at 110 °C for 1.5 min (during desorption), then heated as rapidly as possible to 150 °C and held for 20 min; column bakeout at 190 °C for 10 min.
9

Column 2 conditions: Chromosorb 101 (60/80 mesh) packed in a 6 ft. × 0.1 in. ID glass or stainless steel column with helium carrier gas at 40 mL/min flow rate. Column temperature held isothermal at 80 °C for 4 min, then programmed at 50 °C/min to 120 °C and held for 12 min.


Table 2—Single Laboratory Accuracy and Precision—Method 603

Parameter
Sample matrix
Spike conc. (µg/L)
Average recovery (µg/L)
Standard deviation (µg/L)
Average percent recovery
AcroleinRW5.05.20.2104
RW50.051.40.7103
POTW5.04.00.280
POTW50.044.40.889
IW5.00.10.12
IW100.09.31.19
AcrylonitrileRW5.04.20.284
RW50.051.41.5103
POTW20.020.10.8100
POTW100.0101.31.5101
IW10.09.10.891
IW100.0104.03.2104

RW = Reagent water.

POTW = Prechlorination secondary effluent from a municipal sewage treatment plant.

IW = Industrial wastewater containing an unidentified acrolein reactant.


Table 3—Calibration and QC Acceptance Criteria—Method 603
a

Parameter
Range for Q (µg/L)
Limit for S (µg/L)
Range for X (µg/L)
Range for P, Ps (%)
Acrolein45.9-54.14.642.9-60.188-118
Acrylonitrile41.2-58.89.933.1-69.971-135


a = Criteria were calculated assuming a QC check sample concentration of 50 µg/L.
9

Q = Concentration measured in QC check sample, in µg/L (Section 7.5.3).

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X = Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).






Method 604—Phenols

1. Scope and Application

1.1 This method covers the determination of phenol and certain substituted phenols. The following parameters may be determined by this method:


Parameter
STORET No.
CAS No.
4-Chloro-3-methylphenol3445259-50-7
2–Chlorophenol3458695-57-8
2,4-Dichlorophenol34601120-83-2
2,4-Dimethylphenol34606105-67-9
2,4-Dinitrophenol3461651-28-5
2-Methyl-4,6-dinitrophenol34657534-52-1
2-Nitrophenol3459188-75-5
4-Nitrophenol34646100-02-7
Pentachlorophenol3903287-86-5
Phenol34694108-95-2
2,4,6-Trichlorophenol3462188-06-2

1.2 This is a flame ionization detector gas chromatographic (FIDGC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for derivatization, cleanup, and electron capture detector gas chromatography (ECDGC) that can be used to confirm measurements made by FIDGC. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix. The MDL listed in Table 1 for each parameter was achieved with a flame ionization detector (FID). The MDLs that were achieved when the derivatization cleanup and electron capture detector (ECD) were employed are presented in Table 2.


1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.5 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is acidified and extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to 2-propanol during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the phenols are then measured with an FID.
2


2.2 A preliminary sample wash under basic conditions can be employed for samples having high general organic and organic base interferences.


2.3 The method also provides for a derivatization and column chromatography cleanup procedure to aid in the elimination of interferences.
2 3 The derivatives are analyzed by ECDGC.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
4 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are coextracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The derivatization cleanup procedure in Section 12 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Tables 1 and 2.


3.3 The basic sample wash (Section 10.2) may cause significantly reduced recovery of phenol and 2,4-dimethylphenol. The analyst must recognize that results obtained under these conditions are minimum concentrations.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this mothod has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
5 7 for the information of analyst.


4.2 Special care should be taken in handling pentafluorobenzyl bromide, which is a lachrymator, and 18-crown-6-ether, which is highly toxic.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnel—2-L, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Chromatographic column—100 mm long × 10 mm ID, with Teflon stopcock.


5.2.4 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.5 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.6 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.7 Snyder column, Kuderna-Danish—Two-ball micro (Kontes K-569001-0219 or equivalent).


5.2.8 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.2.9 Reaction flask—15 to 25-mL round bottom flask, with standard tapered joint, fitted with a water-cooled condenser and U-shaped drying tube containing granular calcium chloride.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighting 0.0001 g.


5.6 Gas chromatograph—An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.6.1 Column for underivatized phenols—1.8 m long × 2 mm ID glass, packed with 1% SP-1240DA on Supelcoport (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 11.1.


5.6.2 Column for derivatized phenols—1.8 m long × 2 mm ID glass, packed with 5% OV-17 on Chromosorb W-AW-DMCS (80/100 mesh) or equivalent. This column has proven effective in the analysis of wastewaters for derivatization products of the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 11.1.


5.6.3 Detectors—Flame ionization and electron capture detectors. The FID is used when determining the parent phenols. The ECD is used when determining the derivatized phenols. Guidelines for the use of alternatve detectors are provided in Section 11.1.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.3 Sodium hydroxide solution (1 N)—Dissolve 4 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.4 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400 °C for 4 h in a shallow tray.


6.5 Sodium thiosulfate—(ACS) Granular.


6.6 Sulfuric acid (1 + 1)—Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.


6.7 Sulfuric acid (1 N)—Slowly, add 58 mL of H2SO4 (ACS, sp. gr. 1.84) to reagent water and dilute to 1 L.


6.8 Potassium carbonate—(ACS) Powdered.


6.9 Pentafluorobenzyl bromide (α-Bromopentafluorotoluene)—97% minimum purity.



Note:

This chemical is a lachrymator. (See Section 4.2.)


6.10 18-crown-6-ether (1,4,7,10,13,16-Hexaoxacyclooctadecane)—98% minimum purity.



Note:

This chemical is highly toxic.


6.11 Derivatization reagent—Add 1 mL of pentafluorobenzyl bromide and 1 g of 18-crown-6-ether to a 50-mL volumetric flask and dilute to volume with 2-propanol. Prepare fresh weekly. This operation should be carried out in a hood. Store at 4 °C and protect from light.


6.12 Acetone, hexane, methanol, methylene chloride, 2-propanol, toluene—Pesticide quality or equivalent.


6.13 Silica gel—100/200 mesh, Davison, grade-923 or equivalent. Activate at 130 °C overnight and store in a desiccator.


6.14 Stock standard solutions (1.00 µg/µL)—Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions.


6.14.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in 2-propanol and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.14.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.14.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.15 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 To calibrate the FIDGC for the anaylsis of underivatized phenols, establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure for FIDGC:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with 2-propanol. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 2 to 5 µl, analyze each calibration standard according to Section 11 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure for FIDGC—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with 2-propanol. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 11 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.


RF = (As)(Cis (Ais)(Cs)

Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.


7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound.


7.5 To calibrate the ECDGC for the analysis of phenol derivatives, establish gas chromatographic operating conditions equivalent to those given in Table 2.


7.5.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with 2-propanol. One of the external standards should be at a concentration near, but above, the MDL (Table 2) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.5.2 Each time samples are to be derivatized, simultaneously treat a 1-mL aliquot of each calibration standard as described in Section 12.


7.5.3 After derivatization, analyze 2 to 5 µL of each column eluate collected according to the method beginning in Section 12.8 and tabulate peak height or area responses against the calculated equivalent mass of underivatized phenol injected. The results can be used to prepare a calibration curve for each compound.


7.6 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.6 and 11.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 100 µg/mL in 2-propanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at a concentration of 100 µg/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 3. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter.



Note:

The large number of parameters in Talbe 3 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.


8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.


8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.2.6.2 Beginning with Section 8.2.2, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 100 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any, or, if none, (2) the larger of either 5 times higher than the expected background concentration or 100 µg/L.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 3. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
8 If spiking was performed at a concentration lower than 100 µg/L, the analyst must use either the QC acceptance criteria in Table 3, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 4, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 4, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
8


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 3. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6. It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
9 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
10 Field test kits are available for this purpose.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

10.1 Mark the water meniscus on the side of sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.


10.2 For samples high in organic content, the analyst may solvent wash the sample at basic pH as prescribed in Sections 10.2.1 and 10.2.2 to remove potential method interferences. Prolonged or exhaustive contact with solvent during the wash may result in low recovery of some of the phenols, notably phenol and 2,4-dimethylphenol. For relatively clean samples, the wash should be omitted and the extraction, beginning with Section 10.3, should be followed.


10.2.1 Adjust the pH of the sample to 12.0 or greater with sodium hydroxide solution.


10.2.2 Add 60 mL of methylene chloride to the sample by shaking the funnel for 1 min with periodic venting to release excess pressure. Discard the solvent layer. The wash can be repeated up to two additional times if significant color is being removed.


10.3 Adjust the sample to a pH of 1 to 2 with sulfuric acid.


10.4 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.5 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.6 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.7 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.8 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.9 Increase the temperature of the hot water bath to 95 to 100 °C. Remove the Synder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of 2-propanol. A 5-mL syringe is recommended for this operation. Attach a two-ball micro-Snyder column to the concentrator tube and prewet the column by adding about 0.5 mL of 2-propanol to the top. Place the micro-K-D apparatus on the water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches 2.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Add an additional 2 mL of 2-propanol through the top of the micro-Snyder column and resume concentrating as before. When the apparent volume of liquid reaches 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.10 Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with a minimum amount of 2-propanol. Adjust the extract volume to 1.0 mL. Stopper the concentrator tube and store refrigerated at 4 °C if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with FIDGC analysis (Section 11). If the sample requires further cleanup, proceed to Section 12.


10.11 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Flame Ionization Detector Gas Chromatography

11.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. An example of the separations achieved by this column is shown in Figure 1. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


11.2 Calibrate the system daily as described in Section 7.


11.3 If the internal standard calibration procedure is used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.


11.4 Inject 2 to 5 µL of the sample extract or standard into the gas chromatograph using the solvent-flush technique.
11 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, and the resulting peak size in area or peak height units.


11.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound may be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


11.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


11.7 If the measurement of the peak response is prevented by the presence of interferences, an alternative gas chromatographic procedure is required. Section 12 describes a derivatization and column chromatographic procedure which has been tested and found to be a practical means of analyzing phenols in complex extracts.


12. Derivatization and Electron Capture Detector Gas Chromatography

12.1 Pipet a 1.0-mL aliquot of the 2-propanol solution of standard or sample extract into a glass reaction vial. Add 1.0 mL of derivatizing reagent (Section 6.11). This amount of reagent is sufficient to derivatize a solution whose total phenolic content does not exceed 0.3 mg/mL.


12.2 Add about 3 mg of potassium carbonate to the solution and shake gently.


12.3 Cap the mixture and heat it for 4 h at 80 °C in a hot water bath.


12.4 Remove the solution from the hot water bath and allow it to cool.


12.5 Add 10 mL of hexane to the reaction flask and shake vigorously for 1 min. Add 3.0 mL of distilled, deionized water to the reaction flask and shake for 2 min. Decant a portion of the organic layer into a concentrator tube and cap with a glass stopper.


12.6 Place 4.0 g of silica gel into a chromatographic column. Tap the column to settle the silica gel and add about 2 g of anhydrous sodium sulfate to the top.


12.7 Preelute the column with 6 mL of hexane. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, pipet onto the column 2.0 mL of the hexane solution (Section 12.5) that contains the derivatized sample or standard. Elute the column with 10.0 mL of hexane and discard the eluate. Elute the column, in order, with: 10.0 mL of 15% toluene in hexane (Fraction 1); 10.0 mL of 40% toluene in hexane (Fraction 2); 10.0 mL of 75% toluene in hexane (Fraction 3); and 10.0 mL of 15% 2-propanol in toluene (Fraction 4). All elution mixtures are prepared on a volume: volume basis. Elution patterns for the phenolic derivatives are shown in Table 2. Fractions may be combined as desired, depending upon the specific phenols of interest or level of interferences.


12.8 Analyze the fractions by ECDGC. Table 2 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. An example of the separations achieved by this column is shown in Figure 2.


12.9 Calibrate the system daily with a minimum of three aliquots of calibration standards, containing each of the phenols of interest that are derivatized according to Section 7.5.


12.10 Inject 2 to 5 µL of the column fractions into the gas chromatograph using the solvent-flush technique. Smaller (1.0 µL) volumes can be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, and the resulting peak size in area or peak height units. If the peak response exceeds the linear range of the system, dilute the extract and reanalyze.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample analyzed by FIDGC (without derivatization) as indicated below.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Determine the concentration of individual compounds in the sample analyzed by derivatization and ECDGC according to Equation 4.




Equation 4

where:

A = Mass of underivatized phenol represented by area of peak in sample chromatogram, determined from calibration curve in Section 7.5.3 (ng).

Vi = Volume of eluate injected (µL).

Vt = Total volume of column eluate or combined fractions from which Vi was taken (µL).

Vs = Volume of water extracted in Section 10.10 (mL).

B = Total volume of hexane added in Section 12.5 (mL).

C = Volume of hexane sample solution added to cleanup column in Section 12.7 (mL).

D = Total volume of 2-propanol extract prior to derivatization (mL).

E = Volume of 2-propanol extract carried through derivatization in Section 12.1 (mL).

13.3 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Tables 1 and 2 were obtained using reagent water.
12 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked as six concentrations over the range 12 to 450 µg/L.
13 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships for a flame ionization detector are presented in Table 4.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Phenols in Industrial and Municipal Wastewaters,” EPA 600/4-84-ABC, National Technical Information Service, PBXYZ, Springfield, Virginia 22161, November 1984.


3. Kawahara, F. K. “Microdetermination of Derivatives of Phenols and Mercaptans by Means of Electron Capture Gas Chromatography,” Analytical Chemistry, 40, 1009 (1968).


4. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


5. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


6. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


7. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


8. Provost, L. P., and Elder, R. S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


9. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


10. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methmds for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


11. Burke, J. A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


12. “Development of Detection Limits, EPA Method 604, Phenols,” Special letter report for EPA Contract 68-03-2625, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268.


13. “EPA Method Study 14 Method 604-Phenols,” EPA 600/4-84-044, National Technical Information Service, PB84-196211, Springfield, Virginia 22161, May 1984.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
2-Chlorophenol1.700.31
2-Nitrophenol2.000.45
Phenol3.010.14
2,4-Dimethylphenol4.030.32
2,4-Dichlorophenol4.300.39
2,4,6-Trichlorophenol6.050.64
4-Chloro-3-methylphenol7.500.36
2,4-Dinitrophenol10.0013.0
2-Methyl-4,6-dinitrophenol10.2416.0
Pentachlorophenol12.427.4
4-Nitrophenol24.252.8

Column conditions: Supelcoport (80/100 mesh) coated with 1% SP-1240DA packed in a 1.8 m long × 2 mm ID glass column with nitrogen carrier gas at 30 mL/min flow rate. Column temperature was 80 °C at injection, programmed immediately at 8 °C/min to 150 °C final temperature. MDL were determined with an FID.


Table 2—Silica Gel Fractionation and Electron Capture Gas Chromatography of PFBB Derivatives

Parent compound
Percent recovery by fraction
a
Retention time (min)
Method detection limit (µg/L)
1
2
3
4
2-Chlorophenol9013.30.58
2-Nitrophenol9909.10.77
Phenol90101.82.2
2,4-Dimethylphenol9572.90.63
2,4-Dichlorophenol9515.80.68
2,4,6-Trichlorophenol50507.00.58
4-Chloro-3-methylphenol84144.81.8
Pentachlorophenol752028.80.59
4-Nitrophenol19014.00.70

Column conditions: Chromosorb W-AW-DMCS (80/100 mesh) coated with 5% OV-17 packed in a 1.8 m long × 2.0 mm ID glass column with 5% methane/95% argon carrier gas at 30 mL/min flow rate. Column temperature held isothermal at 200 °C. MDL were determined with an ECD.


a Eluant composition:

Fraction 1—15% toluene in hexane.

Fraction 2—40% toluene in hexane.

Fraction 3—75% toluene in hexane.

Fraction 4—15% 2-propanol in toluene.


Table 3—QC Acceptance Criteria—Method 604

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (percent)
4-Chloro-3-methylphenol10016.656.7-113.449-122
2-Chlorophenol10027.054.1-110.238-126
2,4-Dichlorophenol10025.159.7-103.344-119
2,4-Dimethylphenol10033.350.4-100.024-118
4,6-Dinitro-2-methylphenol10025.042.4-123.630-136
2,4-Dinitrophenol10036.031.7-125.112-145
2-Nitrophenol10022.556.6-103.843-117
4-Nitrophenol10019.022.7-100.013-110
Pentachlorophenol10032.456.7-113.536-134
Phenol10014.132.4-100.023-108
2,4,6-Trichlorophenol10016.660.8-110.453-119

s—Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
—Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps—Percent recovery measured (Section 8.3.2, Section 8.4.2).

Note: These criteria are based directly upon the method performance data in Table 4. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 4.


Table 4—Method Accuracy and Precision as Functions of Concentration—Method 604

Parameter
Accuracy, as recovery, X′ (µg/L)
Single Analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
4-Chloro-3-methylphenol0.87C-1.970.11X
-0.21		0.16X
+ 1.41
2-Chlorophenol0.83C-0.840.18X
+ 0.20		0.21X
+ 0.75
2,4-Dichlorophenol0.81C + 0.480.17X
-0.02		0.18X
+ 0.62
2,4-Dimethylphenol0.62C-1.640.30X
-0.89		0.25X
+ 0.48
4,6-Dinitro-2-methylphenol0.84C-1.010.15X
+ 1.25		0.19X
+ 5.85
2,4-Dinitrophenol0.80C-1.580.27X
-1.15		0.29X
+ 4.51
2-Nitrophenol0.81C-0.760.15X
+ 0.44		0.14X
+ 3.84
4-Nitrophenol0.46C + 0.180.17X
+ 2.43		0.19X
+ 4.79
Pentachlorophenol0.83C + 2.070.22X
-0.58		0.23X
+ 0.57
Phenol0.43C + 0.110.20X
-0.88		0.17X
+ 0.77
2,4,6-Trichlorophenol0.86C-0.400.10X
+ 0.53		0.13X
+ 2.40

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.




Method 605—Benzidines

1. Scope and Application

1.1 This method covers the determination of certain benzidines. The following parameters can be determined by this method:


Parameter
Storet No
CAS No.
Benzidine3912092-87-5
3,3′-Dichlorobenzidine3463191-94-1

1.2 This is a high performance liquid chromatography (HPLC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for the compounds above, identifications should be supported by at least one additional qualitative technique. This method describes electrochemical conditions at a second potential which can be used to confirm measurements made with this method. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for the parameters listed above, using the extract produced by this method.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of the interferences in the sample matrix.


1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.5 This method is restricted to use by or under the supervision of analysts experienced in the use of HPLC instrumentation and in the interpretation of liquid chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with chloroform using liquid-liquid extractions in a separatory funnel. The chloroform extract is extracted with acid. The acid extract is then neutralized and extracted with chloroform. The final chloroform extract is exchanged to methanol while being concentrated using a rotary evaporator. The extract is mixed with buffer and separated by HPLC. The benzidine compounds are measured with an electrochemical detector.
2


2.2 The acid back-extraction acts as a general purpose cleanup to aid in the elimination of interferences.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
3 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedures that are inherent in the extraction step are used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


3.3 Some dye plant effluents contain large amounts of components with retention times closed to benzidine. In these cases, it has been found useful to reduce the electrode potential in order to eliminate interferences and still detect benzidine. (See Section 12.7.)


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health harzard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4 6 for the information of the analyst.


4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: benzidine and 3,3′-dichlorobenzidine. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.


4.3 Exposure to chloroform should be minimized by performing all extractions and extract concentrations in a hood or other well-ventiliated area.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested):


5.2.1 Separatory funnels—2000, 1000, and 250-mL, with Teflon stopcock.


5.2.2 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.2.3 Rotary evaporator.


5.2.4 Flasks—Round bottom, 100-mL, with 24/40 joints.


5.2.5 Centrifuge tubes—Conical, graduated, with Teflon-lined screw caps.


5.2.6 Pipettes—Pasteur, with bulbs.


5.3 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.4 High performance liquid chromatograph (HPLC)—An analytical system complete with column supplies, high pressure syringes, detector, and compatible recorder. A data system is recommended for measuring peak areas and retention times.


5.4.1 Solvent delivery system—With pulse damper, Altex 110A or equivalent.


5.4.2 Injection valve (optional)—Waters U6K or equivalent.


5.4.3 Electrochemical detector—Bioanalytical Systems LC-2A with glassy carbon electrode, or equivalent. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.1.


5.4.4 Electrode polishing kit—Princeton Applied Research Model 9320 or equivalent.


5.4.5 Column—Lichrosorb RP-2, 5 micron particle diameter, in a 25 cm × 4.6 mm ID stainless steel column. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Sodium hydroxide solution (5 N)—Dissolve 20 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.3 Sodium hydroxide solution (1 M)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 1 L.


6.4 Sodium thiosulfate—(ACS) Granular.


6.5 Sodium tribasic phosphate (0.4 M)—Dissolve 160 g of trisodium phosphate decahydrate (ACS) in reagent water and dilute to 1 L.


6.6 Sulfuric acid (1 + 1)—Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.


6.7 Sulfuric acid (1 M)—Slowly, add 58 mL of H2SO4 (ACS, sp. gr. 1.84) to reagent water and dilute to 1 L.


6.8 Acetate buffer (0.1 M, pH 4.7)—Dissolve 5.8 mL of glacial acetic acid (ACS) and 13.6 g of sodium acetate trihydrate (ACS) in reagent water which has been purified by filtration through a RO-4 Millipore System or equivalent and dilute to 1 L.


6.9 Acetonitrile, chloroform (preserved with 1% ethanol), methanol—Pesticide quality or equivalent.


6.10 Mobile phase—Place equal volumes of filtered acetonitrile (Millipore type FH filter or equivalent) and filtered acetate buffer (Millipore type GS filter or equivalent) in a narrow-mouth, glass container and mix thoroughly. Prepare fresh weekly. Degas daily by sonicating under vacuum, by heating and stirring, or by purging with helium.


6.11 Stock standard solutions (1.00 µg/µL)—Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions.


6.11.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in methanol and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.11.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.11.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.12 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish chromatographic operating conditions equivalent to those given in Table 1. The HPLC system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with mobile phase. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using syringe injections of 5 to 25 µL or a constant volume injection loop, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with mobile phase. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using syringe injections of 5 to 25 µL or a constant volume injection loop, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.


RF = (As)(Cis (Ais)(Cs)

Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.


7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound. If serious loss of response occurs, polish the electrode and recalibrate.


7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.9, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing benzidine and/or 3,3′-dichlorobenzidine at a concentration of 50 µg/mL each in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at a concentration of 50 µg/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 50 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or 50 µg/L.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7 If spiking was performed at a concentration lower than 50 µg/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Sections 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as HPLC with a dissimilar column, gas chromatography, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
8 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C and stored in the dark from the time of collection until extraction. Both benzidine and 3,3′-dichlorobenzidine are easily oxidized. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
9 Field test kits are available for this purpose. After mixing, adjust the pH of the sample to a range of 2 to 7 with sulfuric acid.


9.3 If 1,2-diphenylhydrazine is likely to be present, adjust the pH of the sample to 4.0 ±0.2 to prevent rearrangement to benzidine.


9.4 All samples must be extracted within 7 days of collection. Extracts may be held up to 7 days before analysis, if stored under an inert (oxidant free) atmosphere.
2 The extract should be protected from light.


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel. Check the pH of the sample with wide-range pH paper and adjust to within the range of 6.5 to 7.5 with sodium hydroxide solution or sulfuric acid.


10.2 Add 100 mL of chloroform to the sample bottle, seal, and shake 30 s to rinse the inner surface. (Caution: Handle chloroform in a well ventilated area.) Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the chloroform extract in a 250-mL separatory funnel.


10.3 Add a 50-mL volume of chloroform to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the separatory funnel. Perform a third extraction in the same manner.


10.4 Separate and discard any aqueous layer remaining in the 250-mL separatory funnel after combining the organic extracts. Add 25 mL of 1 M sulfuric acid and extract the sample by shaking the funnel for 2 min. Transfer the aqueous layer to a 250-mL beaker. Extract with two additional 25-mL portions of 1 M sulfuric acid and combine the acid extracts in the beaker.


10.5 Place a stirbar in the 250-mL beaker and stir the acid extract while carefully adding 5 mL of 0.4 M sodium tribasic phosphate. While monitoring with a pH meter, neutralize the extract to a pH between 6 and 7 by dropwise addition of 5 N sodium hydroxide solution while stirring the solution vigorously. Approximately 25 to 30 mL of 5 N sodium hydroxide solution will be required and it should be added over at least a 2-min period. Do not allow the sample pH to exceed 8.


10.6 Transfer the neutralized extract into a 250-mL separatory funnel. Add 30 mL of chloroform and shake the funnel for 2 min. Allow the phases to separate, and transfer the organic layer to a second 250-mL separatory funnel.


10.7 Extract the aqueous layer with two additional 20-mL aliquots of chloroform as before. Combine the extracts in the 250-mL separatory funnel.


10.8 Add 20 mL of reagent water to the combined organic layers and shake for 30 s.


10.9 Transfer the organic extract into a 100-mL round bottom flask. Add 20 mL of methanol and concentrate to 5 mL with a rotary evaporator at reduced pressure and 35 °C. An aspirator is recommended for use as the source of vacuum. Chill the receiver with ice. This operation requires approximately 10 min. Other concentration techniques may be used if the requirements of Section 8.2 are met.


10.10 Using a 9-in. Pasteur pipette, transfer the extract to a 15-mL, conical, screw-cap centrifuge tube. Rinse the flask, including the entire side wall, with 2-mL portions of methanol and combine with the original extract.


10.11 Carefully concentrate the extract to 0.5 mL using a gentle stream of nitrogen while heating in a 30 °C water bath. Dilute to 2 mL with methanol, reconcentrate to 1 mL, and dilute to 5 mL with acetate buffer. Mix the extract thoroughly. Cap the centrifuge tube and store refrigerated and protected from light if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with HPLC analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.


10.12 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1,000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.


12. High Performance Liquid Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the HPLC. Included in this table are retention times, capacity factors, and MDL that can be achieved under these conditions. An example of the separations achieved by this HPLC column is shown in Figure 1. Other HPLC columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met. When the HPLC is idle, it is advisable to maintain a 0.1 mL/min flow through the column to prolong column life.


12.2 Calibrate the system daily as described in Section 7.


12.3 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the instrument.


12.4 Inject 5 to 25 µL of the sample extract or standard into the HPLC. If constant volume injection loops are not used, record the volume injected to the nearest 0.05 µL, and the resulting peak size in area or peak height units.


12.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


12.6 If the response for a peak exceeds the working range of the system, dilute the extract with mobile phase and reanalyze.


12.7 If the measurement of the peak response for benzidine is prevented by the presence of interferences, reduce the electrode potential to + 0.6 V and reanalyze. If the benzidine peak is still obscured by interferences, further cleanup is required.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
10 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 7 × MDL to 3000 × MDL.
10


14.3 This method was tested by 17 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 1.0 to 70 µg/L.
11 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Benzidines in Industrial and Muncipal Wastewaters,” EPA 600/4-82-022, National Technical Information Service, PB82-196320, Springfield, Virginia 22161, April 1982.


3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


4. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


8. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


9. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


10. “EPA Method Study 15, Method 605 (Benzidines),” EPA 600/4-84-062, National Technical Information Service, PB84-211176, Springfield, Virginia 22161, June 1984.


11. “EPA Method Validation Study 15, Method 605 (Benzidines),” Report for EPA Contract 68-03-2624 (In preparation).


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Column capacity factor (k′)
Method detection limit (µg/L)
Benzidine6.11.440.08
3,3′-Dichlorobenzidine12.13.840.13

HPLC Column conditions: Lichrosorb RP-2, 5 micron particle size, in a 25 cm × 4.6 mm ID stainless steel column. Mobile Phase: 0.8 mL/min of 50% acetonitrile/50% 0.1M pH 4.7 acetate buffer. The MDL were determined using an electrochemical detector operated at + 0.8 V.


Table 2—QC Acceptance Criteria—Method 605

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (percent)
Benzidine5018.79.1-61.0D-140
3.3′-Dichlorobenzidine5023.618.7-50.05-128

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 605

Parameter
Accuracy, as recovery, X′(µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
Benzidine0.70C + 0.060.28X
+ 0.19		0.40X
+ 0.18
3,3′-Dichlorobenzidine0.66C + 0.230.39X
−0.05		0.38X
+ 0.02

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.



Method 606—Phthalate Ester

1. Scope and Application

1.1 This method covers the determination of certain phthalate esters. The following parameters can be determined by this method:


Parameter
STORET No.
CAS No.
Bis(2-ethylhexyl) phthalate39100117-81-7
Butyl benzyl phthalate3429285-68-7
Di-n-butyl phthalate3911084-74-2
Diethyl phthalate3433684-66-2
Dimethyl phthalate34341131-11-3
Di-n-octyl phthalate34596117-84-0

1.2 This is a gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 608, 609, 611, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.


1.5 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.6 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the phthalate esters are then measured with an electron capture detector.
2


2.2 Analysis for phthalates is especially complicated by their ubiquitous occurrence in the environment. The method provides Florisil and alumina column cleanup procedures to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
3 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Phthalate esters are contaminants in many products commonly found in the laboratory. It is particularly important to avoid the use of plastics because phthalates are commonly used as plasticizers and are easily extracted from plastic materials. Serious phthalate contamination can result at any time, if consistent quality control is not practiced. Great care must be experienced to prevent such contamination. Exhaustive cleanup of reagents and glassware may be required to eliminate background phthalate contamination.
4 5


3.3 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedures in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
6 8 for the information of the analyst.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only).


5.2.1 Separatory funnel—2-L, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Chromatographic column—300 mm long × 10 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0213 or equivalent).


5.2.4 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.5 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.6 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.7 Snyder column, Kuderna-Danish—Two-ball micro (Kontes K-569001-0219 or equivalent).


5.2.8 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.6 Gas chromatograph—An analytical system complete with gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.6.1 Column 1—1.8 m long × 4 mm ID glass, packed with 1.5% SP-2250/1.95% SP-2401 Supelcoport (100/120 mesh) or equivalent. This column was used to develop the method performance statemelts in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.


5.6.2 Column 2—1.8 m long × 4 mm ID glass, packed with 3% OV-1 on Supelcoport (100/120 mesh) or equivalent.


5.6.3 Detector—Electron capture detector. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.1.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Acetone, hexane, isooctane, methylene chloride, methanol—Pesticide quality or equivalent.


6.3 Ethyl ether—nanograde, redistilled in glass if necessary.


6.3.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated by EM Laboratories Quant test strips. (Available from Scientific Products Co., Cat. No. P1126-8, and other suppliers.)


6.3.2 Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each liter of ether.


6.4 Sodium sulfate—(ACS) Granular, anhydrous. Several levels of purification may be required in order to reduce background phthalate levels to an acceptable level: 1) Heat 4 h at 400 °C in a shallow tray, 2) Heat 16 h at 450 to 500 °C in a shallow tray, 3) Soxhlet extract with methylene chloride for 48 h.


6.5 Florisil—PR grade (60/100 mesh). Purchase activated at 1250 °F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. To prepare for use, place 100 g of Florisil into a 500-mL beaker and heat for approximately 16 h at 40 °C. After heating transfer to a 500-mL reagent bottle. Tightly seal and cool to room temperature. When cool add 3 mL of reagent water. Mix thoroughly by shaking or rolling for 10 min and let it stand for at least 2 h. Keep the bottle sealed tightly.


6.6 Alumina—Neutral activity Super I, W200 series (ICN Life Sciences Group, No. 404583). To prepare for use, place 100 g of alumina into a 500-mL beaker and heat for approximately 16 h at 400 °C. After heating transfer to a 500-mL reagent bottle. Tightly seal and cool to room temperature. When cool add 3 mL of reagent water. Mix thoroughly by shaking or rolling for 10 min and let it stand for at least 2 h. Keep the bottle sealed tightly.


6.7 Stock standard solutions (1.00 µg/µL)—Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.


6.7.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in isooctane and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.7.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.7.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.8 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish gas chromatograph operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepared calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with isooctane. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flash. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with isooctane. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.


RF = (As)(Cis (Ais)(Cs)

Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.


7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound.


7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality contrml (QC) check sample concentrate is required containing each parameter of interest at the following concentrations in acetone: butyl benzyl phthalate, 10 µg/mL; bis(2-ethylhexyl) phthalate, 50 µg/mL; di-n-octyl phthalate, 50 µg/mL; any other phthlate, 25 µg/mL. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agancy, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in Table 2 by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at the test concentration in Section 8.2.2 or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or the test concentration in Section 8.2.2.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A-B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
9 If spiking was performed at a concentration lower than the test concentration in Section 8.2.2, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
9


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
10 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.


10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phrase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentrator devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.5 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.7 Increase the temperature of the hot water bath to about 80 °C. Momentarily remove the Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder column. Concentrate the extract as in Section 10.6, except use hexane to prewet the column. The elapsed time of concentration should be 5 to 10 min.


10.8 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for this operation. Adjust the extract volume to 10 mL. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.


10.9 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11. Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use either procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.


11.2 If the entire extract is to be cleaned up by one of the following procedures, it must be concentrated to 2.0 mL. To the concentrator tube in Section 10.8, add a clean boiling chip and attach a two-ball micro-Snyder column. Prewet the column by adding about 0.5 mL of hexane to the top. Place the micro-K-D apparatus on a hot water bath (80 °C) so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of hexane. Adjust the final volume to 2.0 mL and proceed with one of the following cleanup procedures.


11.3 Florisil column cleanup for phthalate esters:


11.3.1 Place 10 g of Florisil into a chromatographic column. Tap the column to settle the Florisil and add 1 cm of anhydrous sodium sulfate to the top.


11.3.2 Preelute the column with 40 mL of hexane. The rate for all elutions should be about 2 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2-mL sample extract onto the column using an additional 2 mL of hexane to complete the transfer. Just prior to exposure of the sodium sulfate layer to the air, add 40 mL of hexane and continue the elution of the column. Discard this hexane eluate.


11.3.3 Next, elute the column with 100 mL of 20% ethyl ether in hexane (V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. Concentrate the collected fraction as in Section 10.6. No solvent exchange is necessary. Adjust the volume of the cleaned up extract to 10 mL in the concentrator tube and analyze by gas chromatography (Section 12).


11.4 Alumina column cleanup for phthalate esters:


11.4.1 Place 10 g of alumina into a chromatographic column. Tap the column to settle the alumina and add 1 cm of anhydrous sodium sulfate to the top.


11.4.2 Preelute the column with 40 mL of hexane. The rate for all elutions should be about 2 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2-mL sample extract onto the column using an additional 2 mL of hexane to complete the transfer. Just prior to exposure of the sodium sulfate layer to the air, add 35 mL of hexane and continue the elution of the column. Discard this hexane eluate.


11.4.3 Next, elute the column with 140 mL of 20% ethyl ether in hexane (V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator type. Concentrate the collected fraction as in Section 10.6. No solvent exchange is necessary. Adjust the volume of the cleaned up extract to 10 mL in the concentrator tube and analyze by gas chromatography (Section 12).


12. Gas Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Column 1 are shown in Figures 1 and 2. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


12.2 Calibrate the system daily as described in Section 7.


12.3 If the internal standard calibration procedure is being used, the internal staldard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.


12.4 Inject 2 to 5 µL of the sample extract or standard into the gas-chromatograph using the solvent-flush technique.
11 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, and the resulting peak size in area or peak height units.


12.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


12.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
12 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 5 × MDL to 1000 × MDL with the following exceptions: dimethyl and diethyl phthalate recoveries at 1000 × MDL were low (70%); bis-2-ethylhexyl and di-n-octyl phthalate recoveries at 5 × MDL were low (60%).
12


14.3 This method was tested by 16 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 0.7 to 106 µg/L.
13 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Phthalates in Industrial and Muncipal Wastewaters,” EPA 600/4-81-063, National Technical Information Service, PB81-232167, Springfield, Virginia 22161, July 1981.


3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


4. Giam, C.S., Chan, H.S., and Nef, G.S. “Sensitive Method for Determination of Phthalate Ester Plasticizers in Open-Ocean Biota Samples,” Analytical Chemistry, 47, 2225 (1975).


5. Giam, C.S., and Chan, H.S. “Control of Blanks in the Analysis of Phthalates in Air and Ocean Biota Samples,” U.S. National Bureau of Standards, Special Publication 442, pp. 701-708, 1976.


6. “Carcinogens—Working with Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


7. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


8. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


9. Provost L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


10. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


11. Burke, J.A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


12. “Method Detection Limit and Analytical Curve Studies, EPA Methods 606, 607, and 608,” Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.


13. “EPA Method Study 16 Method 606 (Phthalate Esters),” EPA 600/4-84-056, National Technical Information Service, PB84-211275, Springfield, Virginia 22161, June 1984.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Column 1
Column 2
Dimethyl phthalate2.030.950.29
Diethyl phthalate2.821.270.49
Di-n-butyl phthalate8.653.500.36
Butyl benzyl phthalate
a 6.94
a 5.11		0.34
Bis(2-ethylhexyl) phthalate
a 8.92
a 10.5		2.0
Di-n-octyl phthalate
a 16.2
a 18.0		3.0

Column 1 conditions: Supelcoport (100/120 mesh) coated with 1.5% SP-2250/1.95% SP-2401 packed in a 1.8 m long × 4 mm ID glass column with 5% methane/95% argon carrier gas at 60 mL/min flow rate. Column temperature held isothermal at 180 °C, except where otherwise indicated.

Column 2 conditions: Supelcoport (100/120 mesh) coated with 3% OV-1 packed in a 1.8 m long × 4 mm ID glass column with 5% methane/95% argon carrier gas at 60 mL/min flow rate. Column temperature held isothermal at 200 °C, except where otherwise indicated.


a 220 °C column temperature.


Table 2—QC Acceptance Criteria—Method 606

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (percent)
Bis(2-ethylhexyl) phthalate5038.41.2-55.9D-158
Butyl benzyl phthalate104.25.7-11.030-136
Di-n-butyl phthalate258.910.3-29.623-136
Diethyl phthalate259.01.9-33.4D-149
Dimethyl phathalate259.51.3-35.5D-156
Di-n-octyl phthalate5013.4D-50.0D-114

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 606

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
Bis(2-ethylhexyl) phthalate0.53C + 2.020.80X
−2.54		0.73X
−0.17
Butyl benzyl phthalate0.82C + 0.130.26X
+ 0.04		0.25X
+ 0.07
Di-n-butyl phthalate0.79C + 0.170.23X
+ 0.20		0.29X
+ 0.06
Diethyl phthalate0.70C + 0.130.27X
+ 0.05		0.45X
+ 0.11
Dimethyl phthalate0.73C + 0.170.26X
+ 0.14		0.44X
+ 0.31
Di-n-octyl phthalate0.35C−0.710.38X
+ 0.71		0.62X
+ 0.34

X
′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.




Method 607—Nitrosamines

1. Scope and Application

1.1 This method covers the determination of certain nitrosamines. The following parameters can be determined by this method:


Parameter
Storet No.
CAS No.
N-Nitrosodimethylamine3443862-75-9
N-Nitrosodiphenylamine3443386-30-6
N-Nitrosodi-n-propylamine34428621-64-7

1.2 This is a gas chromatographic (GC) method applicable to the determination of the parameters listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compmunds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditimns for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for N-nitrosodi-n-propylamine. In order to confirm the presence of N-nitrosodiphenylamine, the cleanup procedure specified in Section 11.3 or 11.4 must be used. In order to confirm the presence of N-nitrosodimethylamine by GC/MS, Column 1 of this method must be substituted for the column recommended in Method 625. Confirmation of these parameters using GC-high resolution mass spectrometry or a Thermal Energy Analyzer is also recommended.
1 2


1.3 The method detection limit (MDL, defined in Section 14.1)
3 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.5 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is washed with dilute hydrochloric acid to remove free amines, dried, and concentrated to a volume of 10 mL or less. After the extract has been exchanged to methanol, it is separated by gas chromatography and the parameters are then measured with a nitrogen-phosphorus detector.
4


2.2 The method provides Florisil and alumina column cleanup procedures to separate diphenylamine from the nitrosamines and to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
5 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedures in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


3.3 N-Nitrosodiphenylamine is reported
6-9 to undergo transnitrosation reactions. Care must be exercised in the heating or concentrating of solutions containing this compound in the presence of reactive amines.


3.4 The sensitive and selective Thermal Energy Analyzer and the reductive Hall detector may be used in place of the nitrogen-phosphorus detector when interferences are encountered. The Thermal Energy Analyzer offers the highest selectivity of the non-MS detectors.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
10-12 for the information of the analyst.


4.2 These nitrosamines are known carcinogens,
13-17 therefore, utmost care must be exercised in the handling of these materials. Nitrosamine reference standards and standard solutions should be handled and prepared in a ventilated glove box within a properly ventilated room.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flowmeter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnels—2-L and 250-mL, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.4 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.5 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.6 Snyder column, Kuderna-Danish—Two-ball micro (Kontes K-569001-0219 or equivalent).


5.2.7 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.2.8 Chromatographic column—Approximately 400 mm long × 22 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0234 or equivalent), for use in Florisil column cleanup procedure.


5.2.9 Chromatographic column—Approximately 300 mm long × 10 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0213 or equivalent), for use in alumina column cleanup procedure.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.6 Gas chromatograph—An analytical system complete with gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.6.1 Column 1—1.8 m long × 4 mm ID glass, packed with 10% Carbowax 20 M/2% KOH on Chromosorb W-AW (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.2.


5.6.2 Column 2—1.8 m long × 4 mm ID glass, packed with 10% SP-2250 on Supel-coport (100/120 mesh) or equivalent.


5.6.3 Detector—Nitrogen-phosphorus, reductive Hall, or Thermal Energy Analyzer detector.
1 2 These detectors have proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1). A nitrogen-phosphorus detector was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.2.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 ml.


6.3 Sodium thiosulfate—(ACS) Granular.


6.4 Sulfuric acid (1 + 1)—Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.


6.5 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400 °C for 4 h in a shallow tray.


6.6 Hydrochloric acid (1 + 9)—Add one volume of concentrated HCl (ACS) to nine volumes of reagent water.


6.7 Acetone, methanol, methylene chloride, pentane—Pesticide quality or equivalent.


6.8 Ethyl ether—Nanograde, redistilled in glass if necessary.


6.8.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated by EM Laboratories Quant test strips. (Available from Scientific Products Co., Cat No. P1126-8, and other suppliers.)


6.8.2 Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each liter of ether.


6.9 Florisil—PR grade (60/100 mesh). Purchase activated at 1250 °F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. Before use, activate each batch at least 16 h at 130 °C in a foil-covered glass container and allow to cool.


6.10 Alumina—Basic activity Super I, W200 series (ICN Life Sciences Group, No. 404571, or equivalent). To prepare for use, place 100 g of alumina into a 500-mL reagent bottle and add 2 mL of reagent water. Mix the alumina preparation thoroughly by shaking or rolling for 10 min and let it stand for at least 2 h. The preparation should be homogeneous before use. Keep the bottle sealed tightly to ensure proper activity.


6.11 Stock standard solutions (1.00 µg/µL)—Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.


6.11.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in methanol and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.11.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.11.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.12 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with methanol. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with methanol. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.


RF = (As)(Cis (Ais)(Cs)

Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.


7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound.


7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.2) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 20 µg/mL in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at a concentration of 20 µg/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 20 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or 20 µg/L.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were caluclated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
18 If spiking was performed at a concentration lower than 20 µg/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria caluclated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T) ±2.44(100 S′/T)%.
18


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
19 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
20 Field test kits are available for this purpose. If N-nitrosodiphenylamine is to be determined, adjust the sample pH to 7 to 10 with sodium hydroxide solution or sulfuric acid.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
4


9.4 Nitrosamines are known to be light sensitive.
7 Samples should be stored in amber or foil-wrapped bottles in order to minimize photolytic decomposition.


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel. Check the pH of the sample with wide-range pH paper and adjust to within the range of 5 to 9 with sodium hydroxide solution or sulfuric acid.


10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.5 Add 10 mL of hydrochloric acid to the combined extracts and shake for 2 min. Allow the layers to separate. Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.7 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of methylene chloride. A 5-mL syringe is recommended for this operation. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If N-nitrosodiphenylamine is to be measured by gas chromatography, the analyst must first use a cleanup column to eliminate diphenylamine interference (Section 11). If N-nitrosodiphenylamine is of no interest, the analyst may proceed directly with gas chromatographic analysis (Section 12).


10.8 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-


mL graduated cylinder. Record the sample volume to the nearest 5 mL.

11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use either procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure. Diphenylamine, if present in the original sample extract, must be separated from the nitrosamines if N-nitrosodiphenylamine is to be determined by this method.


11.2 If the entire extract is to be cleaned up by one of the following procedures, it must be concentrated to 2.0 mL. To the concentrator tube in Section 10.7, add a clean boiling chip and attach a two-ball micro-Snyder column. Prewet the column by adding about 0.5 mL of methylene chloride to the top. Place the micr-K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of methylene chloride. Adjust the final volume to 2.0 mL and proceed with one of the following cleanup procedures.


11.3 Florisil column cleanup for nitrosamines:


11.3.1 Place 22 g of activated Florisil into a 22-mm ID chromatographic column. Tap the column to settle the Florisil and add about 5 mm of anhydrous sodium sulfate to the top.


11.3.2 Preelute the column with 40 mL of ethyl ether/pentane (15 + 85)(V/V). Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2-mL sample extract onto the column using an additional 2 mL of pentane to complete the transfer.


11.3.3 Elute the column with 90 mL of ethyl ether/pentane (15 + 85)(V/V) and discard the eluate. This fraction will contain the diphenylamine, if it is present in the extract.


11.3.4 Next, elute the column with 100 mL of acetone/ethyl ether (5 + 95)(V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. This fraction will contain all of the nitrosamines listed in the scope of the method.


11.3.5 Add 15 mL of methanol to the collected fraction and concentrate as in Section 10.6, except use pentane to prewet the column and set the water bath at 70 to 75 °C. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of pentane. Analyze by gas chromatography (Section 12).


11.4 Alumina column cleanup for nitrosamines:


11.4.1 Place 12 g of the alumina preparation (Section 6.10) into a 10-mm ID chromatographic column. Tap the column to settle the alumina and add 1 to 2 cm of anhydrous sodium sulfate to the top.


11.4.2 Preelute the column with 10 mL of ethyl ether/pentane (3 + 7)(V/V). Discard the eluate (about 2 mL) and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2 mL sample extract onto the column using an additional 2 mL of pentane to complete the transfer.


11.4.3 Just prior to exposure of the sodium sulfate layer to the air, add 70 mL of ethyl ether/pentane (3 + 7)(V/V). Discard the first 10 mL of eluate. Collect the remainder of the eluate in a 500-mL K-D flask equipped with a 10 mL concentrator tube. This fraction contains N-nitrosodiphenylamine and probably a small amount of N-nitrosodi-n-propylamine.


11.4.4 Next, elute the column with 60 mL of ethyl ether/pentane (1 + 1)(V/V), collecting the eluate in a second K-D flask equipped with a 10-mL concentrator tube. Add 15 mL of methanol to the K-D flask. This fraction will contain N-nitrosodimethylamine, most of the N-nitrosodi-n-propylamine and any diphenylamine that is present.


11.4.5 Concentrate both fractions as in Section 10.6, except use pentane to prewet the column. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of pentane. Analyze the fractions by gas chromatography (Section 12).


12. Gas Chromatography

12.1 N-nitrosodiphenylamine completely reacts to form diphenylamine at the normal operating temperatures of a GC injection port (200 to 250 °C). Thus, N-nitrosodiphenylamine is chromatographed and detected as diphenylamine. Accurate determination depends on removal of diphenylamine that may be present in the original extract prior to GC analysis (See Section 11).


12.2 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Column 1 are shown in Figures 1 and 2. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


12.3 Calibrate the system daily as described in Section 7.


12.4 If the extract has not been subjected to one of the cleanup procedures in Section 11, it is necessary to exchange the solvent from methylene chloride to methanol before the thermionic detector can be used. To a 1 to 10-mL volume of methylene chloride extract in a concentrator tube, add 2 mL of methanol and a clean boiling chip. Attach a two-ball micro-Snyder column to the concentrator tube. Prewet the column by adding about 0.5 mL of methylene chloride to the top. Place the micro-K-D apparatus on a boiling (100 °C) water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of methanol. Adjust the final volume to 2.0 mL.


12.5 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.


12.6 Inject 2 to 5 µL of the sample extract or standard into the gas chromatograph using the solvent-flush technique.
21 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, and the resulting peak size in area or peak height units.


12.7 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


12.8 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


12.9 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
3 The MDL concentrations listed in Table 1 were obtained using reagent water.
22 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 4 × MDL to 1000 × MDL.
22


14.3 This method was tested by 17 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 0.8 to 55 µg/L.
23 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. Fine, D.H., Lieb, D., and Rufeh, R. “Principle of Operation of the Thermal Energy Analyzer for the Trace Analysis of Volatile and Non-volatile N-nitroso Compounds,” Journal of Chromatography, 107, 351 (1975).


2. Fine, D.H., Hoffman, F., Rounbehler, D.P., and Belcher, N.M. “Analysis of N-nitroso Compounds by Combined High Performance Liquid Chromatography and Thermal Energy Analysis,” Walker, E.A., Bogovski, P. and Griciute, L., Editors, N-nitroso Compounds—Analysis and Formation, Lyon, International Agency for Research on Cancer (IARC Scientific Publications No. 14), pp. 43-50 (1976).


3. 40 CFR part 136, appendix B.


4. “Determination of Nitrosamines in Industrial and Municipal Wastewaters,” EPA 600/4-82-016, National Technical Information Service, PB82-199621, Springfield, Virginia 22161, April 1982.


5. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


6. Buglass, A.J., Challis, B.C., and Osborn, M.R. “Transnitrosation and Decomposition of Nitrosamines,” Bogovski, P. and Walker, E.A., Editors, N-nitroso Compounds in the Environment, Lyon, International Agency for Research on Cancer (IARC Scientific Publication No. 9), pp. 94-100 (1974).


7. Burgess, E.M., and Lavanish, J.M. “Photochemical Decomposition of N-nitrosamines,” Tetrahedon Letters, 1221 (1964)


8. Druckrey, H., Preussmann, R., Ivankovic, S., and Schmahl, D. “Organotrope Carcinogene Wirkungen bei 65 Verschiedenen N-NitrosoVerbindungen an BD-Ratten,” Z. Krebsforsch., 69, 103 (1967).


9. Fiddler, W. “The Occurrence and Determination of N-nitroso Compounds,” Toxicol. Appl. Pharmacol., 31, 352 (1975).


10. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


11. “OSHA Safety and Health Standards, General Industry,” (29 CFR Part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


12. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


13. Lijinsky, W. “How Nitrosamines Cause Cancer,” New Scientist, 73, 216 (1977).


14. Mirvish, S.S. “N-Nitroso compounds: Their Chemical and in vivo Formation and Possible Importance as Environmental Carcinogens,” J. Toxicol. Environ. Health, 3, 1267 (1977).


15. “Reconnaissance of Environmental Levels of Nitrosamines in the Central United States,” EPA-330/1-77-001, National Enforcement Investigations Center, U.S. Environmental Protection Agency (1977).


16. “Atmospheric Nitrosamine Assessment Report,” Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina (1976).


17. “Scientific and Technical Assessment Report on Nitrosamines,” EPA-660/6-7-001, Office of Research and Development, U.S. Environmental Protection Agency (1976).


18. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value of 1.22 derived in this report.)


19. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


20. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


21. Burke, J. A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


22. “Method Detection Limit and Analytical Curve Studies EPA Methods 606, 607, and 608,” Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.


23. “EPA Method Study 17 Method 607—Nitrosamines,” EPA 600/4-84-051, National Technical Information Service, PB84-207646, Springfield, Virginia 22161, June 1984.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Column 1
Column 2
N-Nitrosodimethylamine4.10.880.15
N-Nitrosodi-n-propylamine12.14.2.46
N-Nitrosodiphenylamine
a
b 12.8
c 6.4		.81

Column 1 conditions: Chromosorb W-AW (80/100 mesh) coated with 10% Carbowax 20 M/2% KOH packed in a 1.8 m long × 4mm ID glass column with helium carrier gas at 40 mL/min flow rate. Column temperature held isothermal at 110 °C, except where otherwise indicated.

Column 2 conditions: Supelcoport (100/120 mesh) coated with 10% SP-2250 packed in a 1.8 m long × 4 mm ID glass column with helium carrier gas at 40 mL/min flow rate. Column temperature held isothermal at 120 °C, except where otherwise indicated.


a Measured as diphenylamine.


b 220 °C column temperature.


c 210 °C column temperature.


Table 2—QC Acceptance Criteria—Method 607

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (percent)
N-Nitrosodimethylamine203.44.6-20.013-109
N-Nitrosodiphenyl206.12.1-24.5D-139
N-Nitrosodi-n-propylamine205.711.5-26.845-146

s = Standard deviation for four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 607

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
N-Nitrosodimethylamine0.37C + 0.060.25X
−0.04		0.25X
+ 0.11
N-Nitrosodiphenylamine0.64C + 0.520.36X
−1.53		0.46X
−0.47
N-Nitrosodi-n-propylamine0.96C−0.070.15X
+ 0.13		0.21X
+ 0.15

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.




Method 608.3—Organochlorine Pesticides And PCBs By GC/HSD

1. Scope and Application

1.1 This method is for determination of organochlorine pesticides and polychlorinated biphenyls (PCBs) in industrial discharges and other environmental samples by gas chromatography (GC) combined with a halogen-specific detector (HSD; e.g., electron capture, electrolytic conductivity), as provided under 40 CFR 136.1. This revision is based on a previous protocol (Reference 1), on the revision promulgated October 26, 1984, on an inter-laboratory method validation study (Reference 2), and on EPA Method 1656 (Reference 16). The analytes that may be qualitatively and quantitatively determined using this method and their CAS Registry numbers are listed in Table 1.


1.2 This method may be extended to determine the analytes listed in Table 2. However, extraction or gas chromatography challenges for some of these analytes may make quantitative determination difficult.


1.3 When this method is used to analyze unfamiliar samples for an analyte listed in Table 1 or Table 2, analyte identification must be supported by at least one additional qualitative technique. This method gives analytical conditions for a second GC column that can be used to confirm and quantify measurements. Additionally, Method 625.1 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative confirmation of results for the analytes listed in Tables 1 and 2 using the extract produced by this method, and Method 1699 (Reference 18) provides high resolution GC/MS conditions for qualitative confirmation of results using the original sample. When such methods are used to confirm the identifications of the target analytes, the quantitative results should be derived from the procedure with the calibration range and sensitivity that are most appropriate for the intended application.


1.4 The large number of analytes in Tables 1 and 2 makes testing difficult if all analytes are determined simultaneously. Therefore, it is necessary to determine and perform quality control (QC) tests for the “analytes of interest” only. The analytes of interest are those required to be determined by a regulatory/control authority or in a permit, or by a client. If a list of analytes is not specified, the analytes in Table 1 must be determined, at a minimum, and QC testing must be performed for these analytes. The analytes in Table 1 and some of the analytes in Table 2 have been identified as Toxic Pollutants (40 CFR 401.15), expanded to a list of Priority Pollutants (40 CFR part 423, appendix A).


1.5 In this revision to Method 608, Chlordane has been listed as the alpha- and gamma- isomers in Table 1. Reporting may be by the individual isomers, or as the sum of the concentrations of these isomers, as requested or required by a regulatory/control authority or in a permit. Technical Chlordane is listed in Table 2 and may be used in cases where historical reporting has only been the Technical Chlordane. Toxaphene and the PCBs have been moved from Table 1 to Table 2 (Additional Analytes) to distinguish these analytes from the analytes required in quality control tests (Table 1). QC acceptance criteria for Toxaphene and the PCBs have been retained in Table 4 and may continue to be applied if desired, or if these analytes are requested or required by a regulatory/control authority or in a permit. Method 1668C (Reference 17) may be useful for determination of PCBs as individual chlorinated biphenyl congeners, and Method 1699 (Reference 18) may be useful for determination of the pesticides listed in this method. However, at the time of writing of this revision, Methods 1668C and 1699 had not been approved for use at 40 CFR part 136.


1.6 Method detection limits (MDLs; Reference 3) for the analytes in Tables 1 and some of the analytes in Table 2 are listed in those tables. These MDLs were determined in reagent water (Reference 3). Advances in analytical technology, particularly the use of capillary (open-tubular) columns, allowed laboratories to routinely achieve MDLs for the analytes in this method that are 2-10 times lower than those in the version promulgated in 1984. The MDL for an analyte in a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.6.1 EPA has promulgated this method at 40 CFR part 136 for use in wastewater compliance monitoring under the National Pollutant Discharge Elimination System (NPDES). The data reporting practices described in section 15.6 are focused on such monitoring needs and may not be relevant to other uses of the method.


1.6.2 This method includes “reporting limits” based on EPA’s “minimum level” (ML) concept (see the glossary in section 23). Tables 1 and 2 contain MDL values and ML values for many of the analytes.


1.7 The separatory funnel and continuous liquid-liquid sample extraction and concentration steps in this method are essentially the same as those steps in Methods 606, 609, 611, and 612. Thus, a single sample may be extracted to measure the analytes included in the scope of each of these methods. Samples may also be extracted using a disk-based solid-phase extraction (SPE) procedure developed by the 3M Corporation and approved by EPA as an Alternate Test Procedure (ATP) for wastewater analyses in 1995 (Reference 20).


1.8 This method is performance-based. It may be modified to improve performance (e.g., to overcome interferences or improve the accuracy of results) provided all performance requirements are met.


1.8.1 Examples of allowed method modifications are described at 40 CFR 136.6. Other examples of allowed modifications specific to this method are described in section 8.1.2.


1.8.2 Any modification beyond those expressly permitted at 40 CFR 136.6 or in section 8.1.2 of this method shall be considered a major modification subject to application and approval of an alternate test procedure under 40 CFR 136.4 and 136.5.


1.8.3 For regulatory compliance, any modification must be demonstrated to produce results equivalent or superior to results produced by this method when applied to relevant wastewaters (section 8.1.2).


1.9 This method is restricted to use by or under the supervision of analysts experienced in the use of GC/HSD. The laboratory must demonstrate the ability to generate acceptable results with this method using the procedure in section 8.2.


1.10 Terms and units of measure used in this method are given in the glossary at the end of the method.


2. Summary of Method

2.1 A measured volume of sample, the amount required to meet an MDL or reporting limit (nominally 1-L), is extracted with methylene chloride using a separatory funnel, a continuous liquid/liquid extractor, or disk-based solid-phase extraction equipment. The extract is dried and concentrated for cleanup, if required. After cleanup, or if cleanup is not required, the extract is exchanged into an appropriate solvent and concentrated to the volume necessary to meet the required compliance or detection limit, and analyzed by GC/HSD.


2.2 Qualitative identification of an analyte in the extract is performed using the retention times on dissimilar GC columns. Quantitative analysis is performed using the peak areas or peak heights for the analyte on the dissimilar columns with either the external or internal standard technique.


2.3 Florisil®, alumina, a C18 solid-phase cleanup, and an elemental sulfur cleanup procedure are provided to aid in elimination of interferences that may be encountered. Other cleanup procedures may be used if demonstrated to be effective for the analytes in a wastewater matrix.


3. Contamination and Interferences

3.1 Solvents, reagents, glassware, and other sample processing lab ware may yield artifacts, elevated baselines, or matrix interferences causing misinterpretation of chromatograms. All materials used in the analysis must be demonstrated free from contamination and interferences by running blanks initially and with each extraction batch (samples started through the extraction process in a given 24-hour period, to a maximum of 20 samples—see Glossary for detailed definition), as described in section 8.5. Specific selection of reagents and purification of solvents by distillation in all-glass systems may be required. Where possible, labware is cleaned by extraction or solvent rinse, or baking in a kiln or oven.


3.2 Glassware must be scrupulously cleaned (Reference 4). Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and reagent water. The glassware should then be drained dry, and heated at 400 °C for 15-30 minutes. Some thermally stable materials, such as PCBs, may require higher temperatures and longer baking times for removal. Solvent rinses with pesticide quality acetone, hexane, or other solvents may be substituted for heating. Do not heat volumetric labware above 90 °C. After drying and cooling, store inverted or capped with solvent-rinsed or baked aluminum foil in a clean environment to prevent accumulation of dust or other contaminants.


3.3 Interferences by phthalate esters can pose a major problem in pesticide analysis when using the electron capture detector. The phthalate esters generally appear in the chromatogram as large late eluting peaks, especially in the 15 and 50% fractions from Florisil®. Common flexible plastics contain varying amounts of phthalates that may be extracted or leached from such materials during laboratory operations. Cross contamination of clean glassware routinely occurs when plastics are handled during extraction steps, especially when solvent-wetted surfaces are handled. Interferences from phthalates can best be minimized by avoiding use of non-fluoropolymer plastics in the laboratory. Exhaustive cleanup of reagents and glassware may be required to eliminate background phthalate contamination (References 5 and 6). Interferences from phthalate esters can be avoided by using a microcoulometric or electrolytic conductivity detector.


3.4 Matrix interferences may be caused by contaminants co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. Interferences extracted from samples high in total organic carbon (TOC) may result in elevated baselines, or by enhancing or suppressing a signal at or near the retention time of an analyte of interest. Analyses of the matrix spike and matrix spike duplicate (Section 8.3) may be useful in identifying matrix interferences, and the cleanup procedures in Section 11 may aid in eliminating these interferences. EPA has provided guidance that may aid in overcoming matrix interferences (Reference 7); however, unique samples may require additional cleanup approaches to achieve the MDLs listed in Tables 1 and 2.


4. Safety

4.1 Hazards associated with each reagent used in this method have not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of safety data sheets (SDSs, OSHA, 29 CFR 1910.12009(g)) should also be made available to all personnel involved in sample handling and chemical analysis. Additional references to laboratory safety are available and have been identified (References 8 and 9) for the information of the analyst.


4.2 The following analytes covered by this method have been tentatively classified as known or suspected human or mammalian carcinogens: 4,4′-DDT, 4,4′-DDD, the BHCs, and the PCBs. Primary standards of these toxic analytes should be prepared in a chemical fume hood, and a NIOSH/MESA approved toxic gas respirator should be worn when high concentrations are handled.


4.3 This method allows the use of hydrogen as a carrier gas in place of helium (section 5.8.2). The laboratory should take the necessary precautions in dealing with hydrogen, and should limit hydrogen flow at the source to prevent buildup of an explosive mixture of hydrogen in air.


5. Apparatus and Materials


Note:

Brand names and suppliers are for illustration purposes only. No endorsement is implied. Equivalent performance may be achieved using equipment and materials other than those specified here. Demonstrating that the equipment and supplies used in the laboratory achieve the required performance is the responsibility of the laboratory. Suppliers for equipment and materials in this method may be found through an on-line search. Please do not contact EPA for supplier information.


5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—Amber glass bottle large enough to contain the necessary sample volume (nominally 1 L), fitted with a fluoropolymer-lined screw cap. Foil may be substituted for fluoropolymer if the sample is not corrosive. If amber bottles are not available, protect samples from light. Unless pre-cleaned, the bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must use a glass or fluoropolymer container and tubing for sample collection. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, rinse the compressible tubing thoroughly with methanol, followed by repeated rinsing with reagent water to minimize the potential for sample contamination. An integrating flow meter is required to collect flow proportional composites. The sample container must be kept refrigerated at ≤6 °C and protected from light during compositing.


5.2. Lab ware.


5.2.1 Extraction.


5.2.1.1 pH measurement.


5.2.1.1.1 pH meter, with combination glass electrode.


5.2.1.1.2 pH paper, wide range (Hydrion Papers, or equivalent).


5.2.1.2 Separatory funnel—Size appropriate to hold the sample and extraction solvent volumes, equipped with fluoropolymer stopcock.


5.2.1.3 Continuous liquid-liquid extractor—Equipped with fluoropolymer or glass connecting joints and stopcocks requiring no lubrication. (Hershberg-Wolf Extractor, Ace Glass Company, Vineland, NJ, or equivalent.)


5.2.1.3.1 Round-bottom flask, 500-mL, with heating mantle.


5.2.1.3.2 Condenser, Graham, to fit extractor.


5.2.1.4 Solid-phase extractor—90-mm filter apparatus (Figure 2) or multi-position manifold.



Note:

The approved ATP for solid-phase extraction is limited to disk-based extraction media and associated peripheral equipment.


5.2.1.4.1 Vacuum system—Capable of achieving 0.1 bar (25 inch) Hg (house vacuum, vacuum pump, or water aspirator), equipped with shutoff valve and vacuum gauge.


5.2.1.4.2 Vacuum trap—Made from 500-mL sidearm flask fitted with single-hole rubber stopper and glass tubing.


5.2.2 Filtration.


5.2.2.1 Glass powder funnel, 125- to 250-mL.


5.2.2.2 Filter paper for above, Whatman 41, or equivalent.


5.2.2.3 Prefiltering aids—90-mm 1-µm glass fiber filter or Empore® Filter Aid 400.


5.2.3 Drying column.


5.2.3.1 Chromatographic column—Approximately 400 mm long x 15 mm ID, with fluoropolymer stopcock and coarse frit filter disc (Kontes or equivalent).


5.2.3.2 Glass wool—Pyrex, extracted with methylene chloride or baked at 450 °C for 1 hour minimum.


5.2.4 Column for Florisil® or alumina cleanup—Approximately 300 mm long x 10 mm ID, with fluoropolymer stopcock. (This column is not required if cartridges containing Florisil® are used.)


5.2.5 Concentration/evaporation.



Note:

Use of a solvent recovery system with the K-D or other solvent evaporation apparatus is strongly recommended.


5.2.5.1 Kuderna-Danish concentrator.


5.2.5.1.1 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes or equivalent). Calibration must be checked at the volumes employed for extract volume measurement. A ground-glass stopper is used to prevent evaporation of extracts.


5.2.5.1.2 Evaporative flask, Kuderna-Danish—500-mL (Kontes or equivalent). Attach to concentrator tube with connectors.


5.2.5.1.3 Snyder column, Kuderna/Danish—Three-ball macro (Kontes or equivalent).


5.2.5.1.4 Snyder column—Two-ball micro (Kontes or equivalent).


5.2.5.1.5 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C), installed in a hood using appropriate engineering controls to limit exposure to solvent vapors.


5.2.5.2 Nitrogen evaporation device—Equipped with heated bath that can be maintained at an appropriate temperature for the solvent and analytes. (N-Evap, Organomation Associates, Inc., or equivalent).


5.2.5.3 Rotary evaporator—Buchi/Brinkman-American Scientific or equivalent, equipped with a variable temperature water bath, vacuum source with shutoff valve at the evaporator, and vacuum gauge.


5.2.5.3.1 A recirculating water pump and chiller are recommended, as use of tap water for cooling the evaporator wastes large volumes of water and can lead to inconsistent performance as water temperatures and pressures vary.


5.2.5.3.2 Round-bottom flask—100-mL and 500-mL or larger, with ground-glass fitting compatible with the rotary evaporator



Note:

This equipment is used to prepare copper foil or copper powder for removing sulfur from sample extracts (see Section 6.7.4).


5.2.5.4 Automated concentrator—Equipped with glassware sufficient to concentrate 3-400 mL extract to a final volume of 1-10 mL under controlled conditions of temperature and nitrogen flow (Turbovap, or equivalent). Follow manufacturer’s directions and requirements.


5.2.5.5 Boiling chips—Glass, silicon carbide, or equivalent, approximately 10/40 mesh. Heat at 400 °C for 30 minutes, or solvent rinse or Soxhlet extract with methylene chloride.


5.2.6 Solid-phase extraction disks—90-mm extraction disks containing 2 g of 8-µm octadecyl (C18) bonded silica uniformly enmeshed in a matrix of inert PTFE fibrils (3M Empore® or equivalent). The disks should not contain any organic compounds, either from the PTFE or the bonded silica, which will leach into the methylene chloride eluant. One liter of reagent water should pass through the disks in 2-5 minutes, using a vacuum of at least 25 inches of mercury.



Note:

Extraction disks from other manufacturers may be used in this procedure, provided that they use the same solid-phase materials (i.e., octadecyl bonded silica). Disks of other diameters also may be used, but may adversely affect the flow rate of the sample through the disk.


5.3 Vials.


5.3.1 Extract storage—10- to 15-mL, amber glass, with fluoropolymer-lined screw cap.


5.3.2 GC autosampler—1- to 5-mL, amber glass, with fluoropolymer-lined screw- or crimp-cap, to fit GC autosampler.


5.4 Balances.


5.4.1 Analytical—Capable of accurately weighing 0.1 mg.


5.4.2 Top loading—Capable of weighing 10 mg.


5.5 Sample cleanup.


5.5.1 Oven—For baking and storage of adsorbents, capable of maintaining a constant temperature (±5 °C) in the range of 105-250 °C.


5.5.2 Muffle furnace—Capable of cleaning glassware or baking sodium sulfate in the range of 400-450 °C.


5.5.3 Vacuum system and cartridges for solid-phase cleanup (see Section 11.2).


5.5.3.1 Vacuum system—Capable of achieving 0.1 bar (25 in.) Hg (house vacuum, vacuum pump, or water aspirator), equipped with shutoff valve and vacuum gauge.


5.5.3.2 VacElute Manifold (Analytichem International, or equivalent).


5.5.3.3 Vacuum trap—Made from 500-mL sidearm flask fitted with single-hole rubber stopper and glass tubing.


5.5.3.4 Rack for holding 50-mL volumetric flasks in the manifold.


5.5.3.5 Cartridge—Mega Bond Elute, Non-polar, C18 Octadecyl, 10 g/60 mL (Analytichem International or equivalent), used for solid-phase cleanup of sample extracts (see Section 11.2).


5.5.4 Sulfur removal tube—40- to 50-mL bottle, test tube, or Erlenmeyer flask with fluoropolymer-lined screw cap.


5.6 Centrifuge apparatus.


5.6.1 Centrifuge—Capable of rotating 500-mL centrifuge bottles or 15-mL centrifuge tubes at 5,000 rpm minimum.


5.6.2 Centrifuge bottle—500-mL, with screw cap, to fit centrifuge.


5.6.3 Centrifuge tube—15-mL, with screw cap, to fit centrifuge.


5.7 Miscellaneous lab ware—Graduated cylinders, pipettes, beakers, volumetric flasks, vials, syringes, and other lab ware necessary to support the operations in this method.


5.8 Gas chromatograph—Dual-column with simultaneous split/splitless, temperature programmable split/splitless (PTV), or on-column injection; temperature program with isothermal holds, and all required accessories including syringes, analytical columns, gases, and detectors. An autosampler is highly recommended because it injects volumes more reproducibly than manual injection techniques. Alternatively, two separate single-column gas chromatographic systems may be employed.


5.8.1 Example columns and operating conditions.


5.8.1.1 DB-608 (or equivalent), 30-m long x 0.53-mm ID fused-silica capillary, 0.83-µm film thickness.


5.8.1.2 DB-1701 (or equivalent), 30-m long x 0.53-mm ID fused-silica capillary, 1.0-µm film thickness.


5.8.1.3 Suggested operating conditions used to meet the retention times shown in Table 3 are:


(a) Carrier gas flow rate: Approximately 7 mL/min,


(b) Initial temperature: 150 °C for 0.5 minute,


(c) Temperature program: 150-270 °C at 5 °C/min, and


(d) Final temperature: 270 °C, until trans-Permethrin elutes.



Note:

Other columns, internal diameters, film thicknesses, and operating conditions may be used, provided that the performance requirements in this method are met. However, the column pair chosen must have dissimilar phases/chemical properties in order to separate the compounds of interest in different retention time order. Columns that only differ in the length, ID, or film thickness, but use the same stationary phase do not qualify as “dissimilar.”


5.8.2 Carrier gas—Helium or hydrogen. Data in the tables in this method were obtained using helium carrier gas. If hydrogen is used, analytical conditions may need to be adjusted for optimum performance, and calibration and all QC tests must be performed with hydrogen carrier gas. See Section 4.3 for precautions regarding the use of hydrogen as a carrier gas.


5.8.3 Detector—Halogen-specific detector (electron capture detector [ECD], electrolytic conductivity detector [ELCD], or equivalent). The ECD has proven effective in the analysis of wastewaters for the analytes listed in Tables 1 and 2, and was used to develop the method performance data in Section 17 and Tables 4 and 5.


5.8.4 Data system—A computer system must be interfaced to the GC that allows continuous acquisition and storage of data from the detectors throughout the chromatographic program. The computer must have software that allows searching GC data for specific analytes, and for plotting responses versus time. Software must also be available that allows integrating peak areas or peak heights in selected retention time windows and calculating concentrations of the analytes.


6. Reagents and Standards

6.1 pH adjustment.


6.1.1 Sodium hydroxide solutions.


6.1.1.1 Concentrated (10 M)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.1.1.2 Dilute (1 M)—Dissolve 40 g NaOH in 1 L of reagent water.


6.1.2 Sulfuric acid (1+1)—Slowly add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.


6.1.3 Hydrochloric acid—Reagent grade, 6 N.


6.2 Sodium thiosulfate—(ACS) granular.


6.3 Sodium sulfate—Sodium sulfate, reagent grade, granular anhydrous (Baker or equivalent), rinsed with methylene chloride, baked in a shallow tray at 450 °C for 1 hour minimum, cooled in a desiccator, and stored in a pre-cleaned glass bottle with screw cap which prevents moisture from entering. If, after heating, the sodium sulfate develops a noticeable grayish cast (due to the presence of carbon in the crystal matrix), that batch of reagent is not suitable for use and should be discarded. Extraction with methylene chloride (as opposed to simple rinsing) and baking at a lower temperature may produce sodium sulfate suitable for use.


6.4 Reagent water—Reagent water is defined as water in which the analytes of interest and interfering compounds are not observed at the MDLs of the analytes in this method.


6.5 Solvents—Methylene chloride, acetone, methanol, hexane, acetonitrile, and isooctane, high purity pesticide quality, or equivalent, demonstrated to be free of the analytes and interferences (section 3). Purification of solvents by distillation in all-glass systems may be required.



Note:

The standards and final sample extracts must be prepared in the same final solvent.


6.6 Ethyl ether—Nanograde, redistilled in glass if necessary. Ethyl ether must be shown to be free of peroxides before use, as indicated by EM Laboratories Quant test strips (available from Scientific Products Co. and other suppliers). Procedures recommended for removal of peroxides are provided with the test strips. After removal of peroxides, add 20 mL of ethyl alcohol preservative to each liter of ether.


6.7 Materials for sample cleanup.


6.7.1 Florisil®—PR grade (60/100 mesh), activated at 650-700 °C, stored in the dark in a glass container with fluoropolymer-lined screw cap. Activate each batch immediately prior to use for 16 hours minimum at 130 °C in a foil-covered glass container and allow to cool. Alternatively, 500 mg cartridges (J.T. Baker, or equivalent) may be used.


6.7.1.1 Cartridge certification—Each cartridge lot must be certified to ensure recovery of the analytes of interest and removal of 2,4,6-trichlorophenol. To make the test mixture, add the trichlorophenol solution (section 6.7.1.3) to the same standard used to prepare the Quality Control Check Sample (section 6.8.3). Transfer the mixture to the column and dry the column. Pre-elute with three 10-mL portions of elution solvent, drying the column between elutions. Elute the cartridge with 10 mL each of methanol and water, as in section 11.2.3.3.


6.7.1.2 Concentrate the eluant to per section 10.3.3, exchange to isooctane or hexane per section 10.3.3, and inject 1.0 µL of the concentrated eluant into the GC using the procedure in section 12. The recovery of all analytes (including the unresolved GC peaks) shall be within the ranges for calibration verification (section 13.6 and Table 4), the recovery of trichlorophenol shall be less than 5%, and no peaks interfering with the target analytes shall be detected. Otherwise the Florisil cartridge is not performing properly and the cartridge lot shall be rejected.


6.7.1.3 Florisil cartridge calibration solution—2,4,6-Trichlorophenol, 0.1 µg/mL in acetone.


6.7.2 SPE elution solvent—Methylene chloride:acetonitrile:hexane (50:3:47).


6.7.3 Alumina, neutral, Brockman Activity I, 80-200 mesh (Fisher Scientific certified, or equivalent). Heat in a glass bottle for 16 hours at 400 to 450 °C. Seal and cool to room temperature. Add 7% (w/w) reagent water and mix for 10 to 12 hours. Keep bottle tightly sealed.


6.7.4 Sulfur removal.


6.7.4.1 Copper foil or powder—Fisher, Alfa Aesar, or equivalent. Cut copper foil into approximately 1-cm squares. Copper must be activated before it may be used, as described below.


6.7.4.1.1 Place the quantity of copper needed for sulfur removal (section 11.5.1.3) in a ground-glass-stoppered Erlenmeyer flask or bottle. Cover the foil or powder with methanol.


6.7.4.1.2 Add HCl dropwise (0.5-1.0 mL) while swirling, until the copper brightens.


6.7.4.1.3 Pour off the methanol/HCl and rinse 3 times with reagent water to remove all traces of acid, then 3 times with acetone, then 3 times with hexane.


6.7.4.1.4 For copper foil, cover with hexane after the final rinse. Store in a stoppered flask under nitrogen until used. For the powder, dry on a rotary evaporator. Store in a stoppered flask under nitrogen until used. Inspect the copper foil or powder before each use. It must have a bright, non-oxidized appearance to be effective. Copper foil or powder that has oxidized may be reactivated using the procedure described above.


6.7.4.2 Tetrabutylammonium sulfite (TBA sulfite)—Prepare as described below.


6.7.4.2.1 Tetrabutylammonium hydrogen sulfate, [CH3(CH2)3]4NHSO4.


6.7.4.2.2 Sodium sulfite, Na2SO3.


6.7.4.2.3 Dissolve approximately 3 g tetrabutylammonium hydrogen sulfate in 100 mL of reagent water in an amber bottle with fluoropolymer-lined screw cap. Extract with three 20-mL portions of hexane and discard the hexane extracts.


6.7.4.2.4 Add 25 g sodium sulfite to produce a saturated solution. Store at room temperature. Replace after 1 month.


6.7.5 Sodium chloride—Reagent grade, prepare at 5% (w/v) solution in reagent water.


6.8 Stock standard solutions—Stock standard solutions may be prepared from pure materials, or purchased as certified solutions. Traceability must be to the National Institute of Standards and Technology (NIST) or other national or international standard, when available. Stock solution concentrations alternative to those below may be used. Because of the toxicity of some of the compounds, primary dilutions should be prepared in a hood, and a NIOSH/MESA approved toxic gas respirator should be worn when high concentrations of neat materials are handled. The following procedure may be used to prepare standards from neat materials.


6.8.1 Accurately weigh about 0.0100 g of pure material in a 10-mL volumetric flask. Dilute to volume in pesticide quality hexane, isooctane, or other suitable solvent. Larger volumes may be used at the convenience of the laboratory. When compound purity is assayed to be 96% or greater, the weight may be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards may be used at any concentration if they are certified by the manufacturer or by an independent source.


6.8.1.1 Unless stated otherwise in this method, store non-aqueous standards in fluoropolymer-lined screw-cap, or heat-sealed, glass containers, in the dark at −20 to −10 °C. Store aqueous standards; e.g., the aqueous LCS (section 8.4), in the dark at ≤6 °C, but do not freeze.


6.8.1.2 Standards prepared by the laboratory may be stored for up to one year, except when comparison with QC check standards indicates that a standard has degraded or become more concentrated due to evaporation, or unless the laboratory has data on file to prove stability for a longer period. Commercially prepared standards may be stored until the expiration date provided by the vendor, except when comparison with QC check standards indicates that a standard has degraded or become more concentrated due to evaporation, or unless the laboratory has data from the vendor on file to prove stability for a longer period.


6.8.2 Calibration solutions—It is necessary to prepare calibration solutions for the analytes of interest (section 1.4) only using an appropriate solvent (isooctane or hexane may be used). Whatever solvent is used, both the calibration standards and the final sample extracts must use the same solvent. Other analytes may be included as desired.


6.8.2.1 Prepare calibration standards for the single-component analytes of interest and surrogates at a minimum of three concentration levels (five are suggested) by adding appropriate volumes of one or more stock standards to volumetric flasks. One of the calibration standards should be at a concentration at or below the ML specified in Table 1, or 2, or as specified by a regulatory/control authority or in a permit. The ML value may be rounded to a whole number that is more convenient for preparing the standard, but must not exceed the ML value listed in Tables 1 or 2 for those analytes which list ML values. Alternatively, the laboratory may establish an ML for each analyte based on the concentration of the lowest calibration standard in a series of standards produced by the laboratory or obtained from a commercial vendor, again, provided that the ML does not exceed the ML in Table 1 and 2, and provided that the resulting calibration meets the acceptance criteria in section 7.5.2 based on the RSD, RSE, or R
2.


(a) The other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the GC system. A minimum of six concentration levels is required for a second order, non-linear (e.g., quadratic; ax
2 + bx + c = 0) calibration (section 7.5.2 or 7.6.2). Calibrations higher than second order are not allowed. A separate standard near the MDL may be analyzed as a check on sensitivity, but should not be included in the linearity assessment. The solvent for the standards must match the final solvent for the sample extracts (e.g., isooctane or hexane).



Note:

The option for non-linear calibration may be necessary to address specific instrumental techniques. However, it is not EPA’s intent to allow non-linear calibration to be used to compensate for detector saturation or to avoid proper instrument maintenance.


(b) Given the number of analytes included in this method, it is highly likely that some will coelute on one or both of the GC columns used for the analysis. Divide the analytes into two or more groups and prepare separate calibration standards for each group, at multiple concentrations (e.g., a five-point calibration will require ten solutions to cover two groups of analytes). Table 7 provides information on dividing the target analytes into separate calibration mixtures that should minimize or eliminate co-elutions. This table is provided solely as guidance, based on the GC columns suggested in this method. If an analyte listed in Table 7 is not an analyte of interest in a given laboratory setting, then it need not be included in a calibration mixture.



Note:

Many commercially available standards are divided into separate mixtures to address this issue.


(c) If co-elutions occur in analysis of a sample, a co-elution on one column is acceptable so long as effective separation of the co-eluting compounds can be achieved on the second column.


6.8.2.2 Multi-component analytes (e.g., PCBs as Aroclors, and Toxaphene).


6.8.2.2.1 A standard containing a mixture of Aroclor 1016 and Aroclor 1260 will include many of the peaks represented in the other Aroclor mixtures. As a result, a multi-point initial calibration employing a mixture of Aroclors 1016 and 1260 at three to five concentrations should be sufficient to demonstrate the linearity of the detector response without the necessity of performing multi-point initial calibrations for each of the seven Aroclors. In addition, such a mixture can be used as a standard to demonstrate that a sample does not contain peaks that represent any one of the Aroclors. This standard can also be used to determine the concentrations of either Aroclor 1016 or Aroclor 1260, should they be present in a sample. Therefore, prepare a minimum of three calibration standards containing equal concentrations of both Aroclor 1016 and Aroclor 1260 by dilution of the stock standard with isooctane or hexane. The concentrations should correspond to the expected range of concentrations found in real samples and should bracket the linear range of the detector.


6.8.2.2.2 Single standards of each of the other five Aroclors are required to aid the analyst in pattern recognition. Assuming that the Aroclor 1016/1260 standards described in Section 6.8.2.2.1 have been used to demonstrate the linearity of the detector, these single standards of the remaining five Aroclors also may be used to determine the calibration factor for each Aroclor. Prepare a standard for each of the other Aroclors. The concentrations should generally correspond to the mid-point of the linear range of the detector, but lower concentrations may be employed at the discretion of the analyst based on project requirements.


6.8.2.2.3 For Toxaphene, prepare a minimum of three calibration standards containing Toxaphene by dilution of the stock standard with isooctane or hexane. The concentrations should correspond to the expected range of concentrations found in real samples and should bracket the linear range of the detector.


6.8.3 Quality Control (QC) Check Sample Concentrate—Prepare one or more mid-level standard mixtures (concentrates) in acetone (or other water miscible solvent). The concentrate is used as the spiking solution with which to prepare the Demonstration of Capabilities (DOC) samples, the Laboratory Control Sample (LCS), and Matrix Spike (MS) and Matrix Spike Duplicate (MSD) samples described in section 8. If prepared by the laboratory (as opposed the purchasing it from a commercial supplier), the concentrate must be prepared independently from the standards used for calibration, but may be prepared from the same source as the second-source standard used for calibration verification (section 7.7). Regardless of the source, the concentrate must be in a water-miscible solvent, as noted above. The concentrate is used to prepare the DOC and LCS (sections 8.2.1 and 8.4) and MS/MSD samples (section 8.3). Depending on the analytes of interest for a given sample (see Section 1.4), multiple solutions and multiple LCS or MS/MSD samples may be required to account for co-eluting analytes. However, a co-elution on one column is acceptable so long as effective separation of the co-eluting compounds can be achieved on the second column. In addition, the concentrations of the MS/MSD samples should reflect any relevant compliance limits for the analytes of interest, as described in section 8.3.1. If a custom spiking solution is required for a specific discharge (section 8.3.1), prepare it separately from the DOC and LCS solution.



Note:

Some commercially available standards are divided into separate mixtures to address the co-elution issue.


6.8.4 Calibration Verification Standards—In order to verify the results of the initial calibration standards, prepare one or more mid-level standard mixtures in isooctane or hexane, using standards obtained from a second source (different manufacturer or different certified lot from the calibration standards). These standards will be analyzed to verify the accuracy of the calibration (sections 7.7 and 13.6.2). As with the QC sample concentrate in section 6.8.3, multiple solutions may be required to address co-elutions among all of the analytes.


6.8.5 Internal standard solution—If the internal standard calibration technique is to be used, prepare pentachloronitrobenzene (PCNB) at a concentration of 10 µg/mL in ethyl acetate. Alternative and multiple internal standards; e.g., tetrachloro-m-xylene, 4,4′-dibromobiphenyl, and/or decachlorobiphenyl may be used provided that the laboratory performs all QC tests and meets all QC acceptance criteria with the alternative or additional internal standard(s) as an integral part of this method.


6.8.6 Surrogate solution—Prepare a solution containing one or more surrogates at a concentration of 2 µg/mL in acetone. Potential surrogates include: dibutyl chlorendate (DBC), tetrachloro-m-xylene (TCMX), 4,4′-dibromobiphenyl, or decachlorobiphenyl. Alternative surrogates and concentrations may be used, provided the laboratory performs all QC tests and meets all QC acceptance criteria with the alternative surrogate(s) as an integral part of this method. If the internal standard calibration technique is used, do not use the internal standard as a surrogate.


6.8.7 DDT and endrin decomposition (breakdown) solution—Prepare a solution containing endrin at a concentration of 50 ng/mL and 4,4′-DDT at a concentration of 100 ng/mL, in isooctane or hexane. A 1-µL injection of this standard will contain 50 picograms (pg) of endrin and 100 pg of DDT. The concentration of the solution may be adjusted by the laboratory to accommodate other injection volumes such that the same masses of the two analytes are introduced into the instrument.


7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those in Section 5.8.1 and Footnote 2 to Table 3. Alternative temperature program and flow rate conditions may be used. The system may be calibrated using the external standard technique (section 7.5) or the internal standard technique (section 7.6). It is necessary to calibrate the system for the analytes of interest (section 1.4) only.


7.2 Separately inject the mid-level calibration standard for each calibration mixture. Store the retention time on each GC column.


7.3 Injection of calibration solutions—Inject a constant volume in the range of 0.5 to 2.0 µL of each calibration solution into the GC column/detector pairs. An alternative volume (see Section 12.3) may be used provided all requirements in this method are met. Beginning with the lowest level mixture and proceeding to the highest level mixture may limit the risk of carryover from one standard to the next, but other sequences may be used. An instrument blank should be analyzed after the highest standard to demonstrate that there is no carry-over within the system for this calibration range.


7.4 For each analyte, compute, record, and store, as a function of the concentration injected, the retention time and peak area on each column/detector system. If multi-component analytes are to be analyzed, store the retention time and peak area for the three to five exclusive (unique large) peaks for each PCB or technical chlordane. Use four to six peaks for toxaphene.


7.5 External standard calibration.


7.5.1 From the calibration data (Section 7.4), calculate the calibration factor (CF) for each analyte at each concentration according to the following equation:



Where:

Cs = Concentration of the analyte in the standard (ng/mL)

As = Peak height or area

For multi-component analytes, choose a series of characteristic peaks for each analyte (3 to 5 for each Aroclor, 4 to 6 for toxaphene) and calculate individual calibration factors for each peak. Alternatively, for toxaphene, sum the areas of all of the peaks in the standard chromatogram and use the summed area to determine the calibration factor. (If this alternative is used, the same approach must be used to quantitate the analyte in the samples.)


7.5.2 Calculate the mean (average) and relative standard deviation (RSD) of the calibration factors. If the RSD is less than 20%, linearity through the origin can be assumed and the average CF can be used for calculations. Alternatively, the results can be used to fit a linear or quadratic regression of response, As, vs. concentration Cs. If used, the regression must be weighted inversely proportional to concentration. The coefficient of determination (R
2) of the weighted regression must be greater than 0.920. Alternatively, the relative standard error (Reference 10) may be used as an acceptance criterion. As with the RSD, the RSE must be less than 20%. If an RSE less than 20% cannot be achieved for a quadratic regression, system performance is unacceptable and the system must be adjusted and re-calibrated.



Note:

Regression calculations are not included in this method because the calculations are cumbersome and because many GC/ECD data systems allow selection of weighted regression for calibration and calculation of analyte concentrations.


7.6 Internal standard calibration.


7.6.1 From the calibration data (Section 7.4), calculate the response factor (RF) for each analyte at each concentration according to the following equation:



Where:

As = Response for the analyte to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (ng/mL)

Cs = Concentration of the analyte to be measured (ng/mL).

7.6.2 Calculate the mean (average) and relative standard deviation (RSD) of the response factors. If the RSD is less than 15%, linearity through the origin can be assumed and the average RF can be used for calculations. Alternatively, the results can be used to prepare a calibration curve of response ratios, As/Ais, vs. concentration ratios, Cs/Cis, for the analyte. A minimum of six concentration levels is required for a non-linear (e.g., quadratic) regression. If used, the regression must be weighted inversely proportional to concentration, and the coefficient of determination of the weighted regression must be greater than 0.920. Alternatively, the relative standard error (Reference 10) may be used as an acceptance criterion. As with the RSD, the RSE must be less than 15%. If an RSE less than 15% cannot be achieved for a quadratic regression, system performance is unacceptable and the system must be adjusted and re-calibrated.


7.7 The working calibration curve, CF, or RF must be verified immediately after calibration and at the beginning and end of each 24-hour shift by the analysis of a mid-level calibration standard. The calibration verification standard(s) must be obtained from a second manufacturer or a manufacturer’s batch prepared independently from the batch used for calibration (Section 6.8.4). Requirements for calibration verification are given in Section 13.6 and Table 4. Alternatively, calibration verification may be performed after a set number of injections (e.g., every 20 injections), to include injection of extracts of field samples, QC samples, instrument blanks, etc. (i.e., it is based on the number of injections performed, not sample extracts). The time for the injections may not exceed 24 hours.



Note:

The 24-hour shift begins after analysis of the combined QC standard (calibration verification) and ends 24 hours later. The ending calibration verification standard is run immediately after the last sample run during the 24-hour shift, so the beginning and ending calibration verifications are outside of the 24-hour shift. If calibration verification is based on the number of injections instead of time, then the ending verification standard for one group of injections may be used as the beginning verification for the next group of injections.


7.8 Florisil® calibration—The column cleanup procedure in Section 11.3 utilizes Florisil column chromatography. Florisil® from different batches or sources may vary in adsorptive capacity. To standardize the amount of Florisil® which is used, use of the lauric acid value (Reference 11) is suggested. The referenced procedure determines the adsorption from a hexane solution of lauric acid (mg) per g of Florisil®. The amount of Florisil® to be used for each column is calculated by dividing 110 by this ratio and multiplying by 20 g. If cartridges containing Florisil® are used, then this step is not necessary.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and ongoing analysis of spiked samples and blanks to evaluate and document data quality. The laboratory must maintain records to document the quality of data generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet performance requirements of this method. A quality control check standard (LCS, section 8.4) must be prepared and analyzed with each batch of samples to confirm that the measurements were performed in an in-control mode of operation. A laboratory may develop its own performance criteria (as QC acceptance criteria), provided such criteria are as or more restrictive than the criteria in this method.


8.1.1 The laboratory must make an initial demonstration of the capability (IDC) to generate acceptable precision and recovery with this method. This demonstration is detailed in Section 8.2. On a continuing basis, the laboratory must repeat demonstration of capability (DOC) at least annually.


8.1.2 In recognition of advances that are occurring in analytical technology, and to overcome matrix interferences, the laboratory is permitted certain options (section 1.8 and 40 CFR 136.6(b) [Reference 12]) to improve separations or lower the costs of measurements. These options may include alternative extraction (e.g., other solid-phase extraction materials and formats), concentration, and cleanup procedures, and changes in GC columns (Reference 12). Alternative determinative techniques, such as the substitution of spectroscopic or immunoassay techniques, and changes that degrade method performance, are not allowed. If an analytical technique other than the techniques specified in this method is used, that technique must have a specificity equal to or greater than the specificity of the techniques in this method for the analytes of interest. The laboratory is also encouraged to participate in performance evaluation studies (see section 8.8).


8.1.2.1 Each time a modification listed above is made to this method, the laboratory is required to repeat the procedure in section 8.2. If the detection limit of the method will be affected by the change, the laboratory is required to demonstrate that the MDLs (40 CFR part 136, appendix B) are lower than one-third the regulatory compliance limit or as low as the MDLs in this method, whichever are greater. If calibration will be affected by the change, the instrument must be recalibrated per section 7. Once the modification is demonstrated to produce results equivalent or superior to results produced by this method as written, that modification may be used routinely thereafter, so long as the other requirements in this method are met (e.g., matrix spike/matrix spike duplicate recovery and relative percent difference).


8.1.2.1.1 If an allowed method modification, is to be applied to a specific discharge, the laboratory must prepare and analyze matrix spike/matrix spike duplicate (MS/MSD) samples (section 8.3) and LCS samples (section 8.4). The laboratory must include surrogates (Section 8.7) in each of the samples. The MS/MSD and LCS samples must be fortified with the analytes of interest (section 1.4). If the modification is for nationwide use, MS/MSD samples must be prepared from a minimum of nine different discharges (See section 8.1.2.1.2), and all QC acceptance criteria in this method must be met. This evaluation only needs to be performed once other than for the routine QC required by this method (for example it could be performed by the vendor of an alternative material) but any laboratory using that specific material must have the results of the study available. This includes a full data package with the raw data that will allow an independent reviewer to verify each determination and calculation performed by the laboratory (see section 8.1.2.2.5, items (a)-(q)).


8.1.2.1.2 Sample matrices on which MS/MSD tests must be performed for nationwide use of an allowed modification:


(a) Effluent from a publicly owned treatment works (POTW).


(b) ASTM D5905 Standard Specification for Substitute Wastewater.


(c) Sewage sludge, if sewage sludge will be in the permit.


(d) ASTM D1141 Standard Specification for Substitute Ocean Water, if ocean water will be in the permit.


(e) Untreated and treated wastewaters up to a total of nine matrix types (see https://www.epa.gov/eg/industrial-effluent-guidelines for a list of industrial categories with existing effluent guidelines).


(i) At least one of the above wastewater matrix types must have at least one of the following characteristics:


(A) Total suspended solids greater than 40 mg/L.


(B) Total dissolved solids greater than 100 mg/L.


(C) Oil and grease greater than 20 mg/L.


(D) NaCl greater than 120 mg/L.


(E) CaCO3 greater than 140 mg/L.


(ii) The interim acceptance criteria for MS, MSD recoveries that do not have recovery limits in Table 4 or developed in section 8.3.3, and for surrogates that do not have recovery limits developed in section 8.6, must be no wider than 60-140%, and the relative percent difference (RPD) of the concentrations in the MS and MSD that do not have RPD limits in Table 4 or developed in section 8.3.3, must be less than 30%. Alternatively, the laboratory may use the laboratory’s in-house limits if they are tighter.


(f) A proficiency testing (PT) sample from a recognized provider, in addition to tests of the nine matrices (section 8.1.2.1.1).


8.1.2.2 The laboratory must maintain records of modifications made to this method. These records include the following, at a minimum:


8.1.2.2.1 The names, titles, and business street addresses, telephone numbers, and email addresses, of the analyst(s) that performed the analyses and modification, and of the quality control officer that witnessed and will verify the analyses and modifications.


8.1.2.2.2 A list of analytes, by name and CAS Registry number.


8.1.2.2.3 A narrative stating reason(s) for the modifications.


8.1.2.2.4 Results from all quality control (QC) tests comparing the modified method to this method, including:


(a) Calibration (section 7).


(b) Calibration verification (section 13.6).


(c) Initial demonstration of capability (section 8.2).


(d) Analysis of blanks (section 8.5).


(e) Matrix spike/matrix spike duplicate analysis (section 8.3).


(f) Laboratory control sample analysis (section 8.4).


8.1.2.2.5 Data that will allow an independent reviewer to validate each determination by tracing the instrument output (peak height, area, or other signal) to the final result. These data are to include:


(a) Sample numbers and other identifiers.


(b) Extraction dates.


(c) Analysis dates and times.


(d) Analysis sequence/run chronology.


(e) Sample weight or volume (section 10).


(f) Extract volume prior to each cleanup step (sections 10 and 11).


(g) Extract volume after each cleanup step (section 11).


(h) Final extract volume prior to injection (sections 10 and 12).


(i) Injection volume (sections 12.3 and 13.2).


(j) Sample or extract dilution (section 15.4).


(k) Instrument and operating conditions.


(l) Column (dimensions, material, etc.).


(m) Operating conditions (temperatures, flow rates, etc.).


(n) Detector (type, operating conditions, etc.).


(o) Chromatograms and other recordings of raw data.


(p) Quantitation reports, data system outputs, and other data to link the raw data to the results reported.


(q) A written Standard Operating Procedure (SOP).


8.1.2.2.6 Each individual laboratory wishing to use a given modification must perform the start-up tests in section 8.1.2 (e.g., DOC, MDL), with the modification as an integral part of this method prior to applying the modification to specific discharges. Results of the DOC must meet the QC acceptance criteria in Table 5 for the analytes of interest (section 1.4), and the MDLs must be equal to or lower than the MDLs in Tables 1 and 2 for the analytes of interest.


8.1.3 Before analyzing samples, the laboratory must analyze a blank to demonstrate that interferences from the analytical system, lab ware, and reagents, are under control. Each time a batch of samples is extracted or reagents are changed, a blank must be extracted and analyzed as a safeguard against laboratory contamination. Requirements for the blank are given in section 8.5.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze samples to monitor and evaluate method and laboratory performance on the sample matrix. The procedure for spiking and analysis is given in section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through analysis of a quality control check sample (laboratory control sample, LCS; on-going precision and recovery sample, OPR) that the measurement system is in control. This procedure is described in Section 8.4.


8.1.6 The laboratory should maintain performance records to document the quality of data that is generated. This procedure is given in section 8.7.


8.1.7 The large number of analytes tested in performance tests in this method present a substantial probability that one or more will fail acceptance criteria when all analytes are tested simultaneously, and a re-test (reanalysis) is allowed if this situation should occur. If, however, continued re-testing results in further repeated failures, the laboratory should document the failures and either avoid reporting results for the analytes that failed or report the problem and failures with the data. A QC failure does not relieve a discharger or permittee of reporting timely results.


8.2 Demonstration of capability (DOC)—To establish the ability to generate acceptable recovery and precision, the laboratory must perform the DOC in sections 8.2.1 through 8.2.6 for the analytes of interest initially and in an on-going manner at least annually. The laboratory must also establish MDLs for the analytes of interest using the MDL procedure at 40 CFR part 136, appendix B. The laboratory’s MDLs must be equal to or lower than those listed in Tables 1 or 2, or lower than one-third the regulatory compliance limit, whichever is greater. For MDLs not listed in Tables 1 or 2, the laboratory must determine the MDLs using the MDL procedure at 40 CFR part 136, appendix B under the same conditions used to determine the MDLs for the analytes listed in Tables 1 and 2. When analyzing the PCBs as Aroclors, it is only necessary to establish an MDL for one of the multi-component analytes (e.g., PCB 1254), or the mixture of Aroclors 1016 and 1260 may be used to establish MDLs for all of the Aroclors. Similarly, MDLs for other multi-component analytes (e.g., Chlordanes) may be determined using only one of the major components. All procedures used in the analysis, including cleanup procedures, must be included in the DOC.


8.2.1 For the DOC, a QC check sample concentrate containing each analyte of interest (section 1.4) is prepared in a water-miscible solvent using the solution in section 6.8.3.



Note:

QC check sample concentrates are no longer available from EPA.


8.2.2 Using a pipet or syringe, prepare four QC check samples by adding an appropriate volume of the concentrate and of the surrogate(s) to each of four 1-L aliquots of reagent water. Swirl or stir to mix.


8.2.3 Extract and analyze the well-mixed QC check samples according to the method beginning in section 10.


8.2.4 Calculate the average percent recovery (X) and the standard deviation (s) of the percent recovery for each analyte using the four results.


8.2.5 For each analyte, compare s and X with the corresponding acceptance criteria for precision and recovery in Table 4. For analytes in Table 2 that are not listed in Table 4, QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 12 and 13). If s and X for all analytes of interest meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for recovery, system performance is unacceptable for that analyte.



Note:

The large number of analytes in Tables 1 and 2 present a substantial probability that one or more will fail at least one of the acceptance criteria when many or all analytes are determined simultaneously.


8.2.6 When one or more of the analytes tested fail at least one of the acceptance criteria, repeat the test for only the analytes that failed. If results for these analytes pass, system performance is acceptable and analysis of samples and blanks may proceed. If one or more of the analytes again fail, system performance is unacceptable for the analytes that failed the acceptance criteria. Correct the problem and repeat the test (section 8.2). See section 8.1.7 for disposition of repeated failures.



Note:

To maintain the validity of the test and re-test, system maintenance and/or adjustment is not permitted between this pair of tests.


8.3 Matrix spike and matrix spike duplicate (MS/MSD)—The purpose of the MS/MSD requirement is to provide data that demonstrate the effectiveness of the method as applied to the samples in question by a given laboratory, and both the data user (discharger, permittee, regulated entity, regulatory/control authority, customer, other) and the laboratory share responsibility for provision of such data. The data user should identify the sample and the analytes of interest (section 1.4) to be spiked and provide sufficient sample volume to perform MS/MSD analyses. The laboratory must, on an ongoing basis, spike at least 5% of the samples in duplicate from each discharge being monitored to assess accuracy (recovery and precision). If direction cannot be obtained from the data user, the laboratory must spike at least one sample in duplicate per extraction batch of up to 20 samples with the analytes in Table 1. Spiked sample results should be reported only to the data user whose sample was spiked, or as requested or required by a regulatory/control authority, or in a permit.


8.3.1. If, as in compliance monitoring, the concentration of a specific analyte will be checked against a regulatory concentration limit, the concentration of the spike should be at that limit; otherwise, the concentration of the spike should be one to five times higher than the background concentration determined in section 8.3.2, at or near the midpoint of the calibration range, or at the concentration in the LCS (section 8.4) whichever concentration would be larger. When no information is available, the mid-point of the calibration may be used.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of the each analyte of interest. If necessary to meet the requirement in section 8.3.1, prepare a new check sample concentrate (section 8.2.1) appropriate for the background concentration. Spike and analyze two additional sample aliquots of the same volume as the original sample, and determine the concentrations after spiking (A1 and A2) of each analyte. Calculate the percent recoveries (P1 and P2) as:



where T is the known true value of the spike.

Also calculate the relative percent difference (RPD) between the concentrations (A1 and A2):



8.3.3 Compare the percent recoveries (P1 and P2) and the RPD for each analyte in the MS/MSD aliquots with the corresponding QC acceptance criteria for recovery (P) and RPD in Table 4.


(a) If any individual P falls outside the designated range for recovery in either aliquot, or the RPD limit is exceeded, the result for the analyte in the unspiked sample is suspect and may not be reported or used for permitting or regulatory compliance. See section 8.1.7 for disposition of failures.


(b) For analytes in Table 2 not listed in Table 4, QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 12 and 13).


8.3.4 After analysis of a minimum of 20 MS/MSD samples for each target analyte and surrogate, and if the laboratory chooses to develop and apply optional in-house QC limits, the laboratory should calculate and apply the optional in-house QC limits for recovery and RPD of future MS/MSD samples (Section 8.3). The optional in-house QC limits for recovery are calculated as the mean observed recovery ±3 standard deviations, and the upper QC limit for RPD is calculated as the mean RPD plus 3 standard deviations of the RPDs. The in-house QC limits must be updated at least every two years and re-established after any major change in the analytical instrumentation or process. At least 80% of the analytes tested in the MS/MSD must have in-house QC acceptance criteria that are tighter than those in Table 4 and the remaining analytes (those not included in the 80%) must meet the acceptance criteria in Table 4. If an in-house QC limit for the RPD is greater than the limit in Table 4, then the limit in Table 4 must be used. Similarly, if an in-house lower limit for recovery is below the lower limit in Table 4, then the lower limit in Table 4 must be used, and if an in-house upper limit for recovery is above the upper limit in Table 4, then the upper limit in Table 4 must be used. The laboratory must evaluate surrogate recovery data in each sample against its in-house surrogate recovery limits. The laboratory may use 60 -140% as interim acceptance criteria for surrogate recoveries until in-house limits are developed. Alternatively, surrogate recovery limits may be developed from laboratory control charts. In-house QC acceptance criteria must be updated at least every two years.


8.4 Laboratory control sample (LCS)—A QC check sample (laboratory control sample, LCS; on-going precision and recovery sample, OPR) containing each single-component analyte of interest (section 1.4) must be extracted, concentrated, and analyzed with each extraction batch of up to 20 samples (section 3.1) to demonstrate acceptable recovery of the analytes of interest from a clean sample matrix. If multi-peak analytes are required, extract and prepare at least one as an LCS for each batch. Alternatively, the laboratory may set up a program where multi-peak LCS is rotated with a single-peak LCS.


8.4.1 Prepare the LCS by adding QC check sample concentrate (sections 6.8.3 and 8.2.1) to reagent water. Include all analytes of interest (section 1.4) in the LCS. The volume of reagent water must be the same as the nominal volume used for the sample, the DOC (Section 8.2), the blank (section 8.5), and the MS/MSD (section 8.3). Also add a volume of the surrogate solution (section 6.8.6).


8.4.2 Analyze the LCS prior to analysis of samples in the extraction batch (Section 3.1). Determine the concentration (A) of each analyte. Calculate the percent recovery as:



where T is the true value of the concentration in the LCS.

8.4.3 For each analyte, compare the percent recovery (P) with its corresponding QC acceptance criterion in Table 4. For analytes of interest in Table 2 not listed in Table 4, use the QC acceptance criteria developed for the MS/MSD (section 8.3.3.2), or limits based on laboratory control charts. If the recoveries for all analytes of interest fall within the designated ranges, analysis of blanks and field samples may proceed. If any individual recovery falls outside the range, proceed according to section 8.4.4.



Note:

The large number of analytes in Tables 1 and 2 present a substantial probability that one or more will fail the acceptance criteria when all analytes are tested simultaneously. Because a re-test is allowed in event of failure (sections 8.1.7 and 8.4.4), it may be prudent to extract and analyze two LCSs together and evaluate results of the second analysis against the QC acceptance criteria only if an analyte fails the first test.


8.4.4 Repeat the test only for those analytes that failed to meet the acceptance criteria (P). If these analytes now pass, system performance is acceptable and analysis of blanks and samples may proceed. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, repeat the test using a fresh LCS (section 8.2.1) or an LCS prepared with a fresh QC check sample concentrate (section 8.2.1), or perform and document system repair. Subsequent to analysis of the LCS prepared with a fresh sample concentrate, or to system repair, repeat the LCS test (Section 8.4). If failure of the LCS indicates a systemic problem with samples in the batch, re-extract and re-analyze the samples in the batch. See Section 8.1.7 for disposition of repeated failures.


8.4.5 After analysis of 20 LCS samples, and if the laboratory chooses to develop and apply optional in-house QC limits, the laboratory should calculate and apply the optional in-house QC limits for recovery of future LCS samples (section 8.4). Limits for recovery in the LCS should be calculated as the mean recovery ±3 standard deviations. A minimum of 80% of the analytes tested for in the LCS must have QC acceptance criteria tighter than those in Table 4, and the remaining analytes (those not included in the 80%) must meet the acceptance criteria in Table 4. If an in-house lower limit for recovery is lower than the lower limit in Table 4, the lower limit in Table 4 must be used, and if an in-house upper limit for recovery is higher than the upper limit in Table 4, the upper limit in Table 4 must be used. Many of the analytes and surrogates do not contain acceptance criteria. The laboratory should use 60-140% as interim acceptance criteria for recoveries of spiked analytes and surrogates that do not have recovery limits specified in Table 4, and at least 80% of the surrogates must meet the 60-140% interim criteria until in-house LCS and surrogate limits are developed. Alternatively, acceptance criteria for analytes that do not have recovery limits in Table 4 may be based on laboratory control charts. In-house QC acceptance criteria must be updated at least every two years.


8.5 Blank—Extract and analyze a blank with each extraction batch (section 3.1) to demonstrate that the reagents and equipment used for preparation and analysis are free from contamination.


8.5.1 Prepare the blank from reagent water and spike it with the surrogates. The volume of reagent water must be the same as the volume used for samples, the DOC (section 8.2), the LCS (section 8.4), and the MS/MSD (section 8.3). Extract, concentrate, and analyze the blank using the same procedures and reagents used for the samples, LCS, and MS/MSD in the batch. Analyze the blank immediately after analysis of the LCS (section 8.4) and prior to analysis of the MS/MSD and samples to demonstrate freedom from contamination.


8.5.2 If any analyte of interest is found in the blank at a concentration greater than the MDL for the analyte, at a concentration greater than one-third the regulatory compliance limit, or at a concentration greater than one-tenth the concentration in a sample in the batch (section 3.1), whichever is greatest, analysis of samples must be halted and samples in the batch must be re-extracted and the extracts reanalyzed. Samples in a batch must be associated with an uncontaminated blank before the results for those samples may be reported or used for permitting or regulatory compliance purposes. If re-testing of blanks results in repeated failures, the laboratory should document the failures and report the problem and failures with the data.


8.6 Surrogate recovery—The laboratory must spike all samples with the surrogate standard spiking solution (section 6.8.6) per section 10.2.2 or 10.4.2, analyze the samples, and calculate the percent recovery of each surrogate. QC acceptance criteria for surrogates must be developed by the laboratory (section 8.4). If any recovery fails its criterion, attempt to find and correct the cause of the failure, and if sufficient volume is available, re-extract another aliquot of the affected sample; otherwise, see section 8.1.7 for disposition of repeated failures.


8.7 As part of the QC program for the laboratory, it is suggested but not required that method accuracy for wastewater samples be assessed and records maintained. After analysis of five or more spiked wastewater samples as in Section 8.3, calculate the average percent recovery (X) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent interval from X−2sp to X+2sp. For example, if X = 90% and sp = 10%, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each analyte on a regular basis to ensure process control (e.g., after each 5-10 new accuracy measurements). If desired, statements of accuracy for laboratory performance, independent of performance on samples, may be developed using LCSs.


8.8 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with another dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Collect samples as grab samples in glass bottles, or in refrigerated bottles using automatic sampling equipment. Collect 1-L of ambient waters, effluents, and other aqueous samples. If high concentrations of the analytes of interest are expected (e.g., for untreated effluents or in-process waters), collect a smaller volume (e.g., 250 mL), but not less than 100 mL, in addition to the 1-L sample. Follow conventional sampling practices, except do not pre-rinse the bottle with sample before collection. Automatic sampling equipment must be as free as possible of polyvinyl chloride or other tubing or other potential sources of contamination. If needed, collect additional sample(s) for the MS/MSD (section 8.3).


9.2 Ice or refrigerate the sample at ≤6 °C from the time of collection until extraction, but do not freeze. If aldrin is to be determined and residual chlorine is present, add 80 mg/L of sodium thiosulfate but do not add excess. Any method suitable for field use may be employed to test for residual chlorine (Reference 14). If sodium thiosulfate interferes in the determination of the analytes, an alternative preservative (e.g., ascorbic acid or sodium sulfite) may be used.


9.3 Extract all samples within seven days of collection and completely analyze within 40 days of extraction (Reference 1). If the sample will not be extracted within 72 hours of collection, adjust the sample pH to a range of 5.0-9.0 with sodium hydroxide solution or sulfuric acid. Record the volume of acid or base used.


10. Sample Extraction

10.1 This section contains procedures for separatory funnel liquid-liquid extraction (SFLLE, section 10.2), continuous liquid-liquid extraction (CLLE, section 10.4), and disk-based solid-phase extraction (SPE, section 10.5). SFLLE is faster, but may not be as effective as CLLE for extracting polar analytes. SFLLE is labor intensive and may result in formation of emulsions that are difficult to break. CLLE is less labor intensive, avoids emulsion formation, but requires more time (18-24 hours), more hood space, and may require more solvent. SPE can be faster, unless the particulate load in an aqueous sample is so high that it slows the filtration process. If an alternative extraction scheme to those detailed in this method is used, all QC tests must be performed and all QC acceptance criteria must be met with that extraction scheme as an integral part of this method.


10.2 Separatory funnel liquid-liquid extraction (SFLLE).


10.2.1 The SFLLE procedure below assumes a sample volume of 1 L. When a different sample volume is extracted, adjust the volume of methylene chloride accordingly.


10.2.2 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into the separatory funnel. Pipet the surrogate standard spiking solution (section 6.8.6) into the separatory funnel. If the sample will be used for the LCS or MS or MSD, pipet the appropriate QC check sample concentrate (section 8.3 or 8.4) into the separatory funnel. Mix well. If the sample arrives in a larger sample bottle, 1 L may be measured in a graduated cylinder, then added to the separatory funnel.



Note:

Instances in which the sample is collected in an oversized bottle should be reported by the laboratory to the data user. Of particular concern is that fact that this practice precludes rinsing the empty bottle with solvent as described below, which could leave hydrophobic pesticides on the wall of the bottle, and underestimate the actual sample concentrations.


10.2.3 Add 60 mL of methylene chloride to the sample bottle, seal, and shake for 30 seconds to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for two minutes with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 minutes. If an emulsion forms and the emulsion interface between the layers is more than one-third the volume of the solvent layer, employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, use of phase-separation paper, centrifugation, salting, freezing, or other physical methods. Collect the methylene chloride extract in a flask. If the emulsion cannot be broken (recovery of less than 80% of the methylene chloride, corrected for the water solubility of methylene chloride), transfer the sample, solvent, and emulsion into the extraction chamber of a continuous extractor and proceed as described in section 10.4.


10.2.4 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the flask. Perform a third extraction in the same manner. Proceed to macro-concentration (section 10.3.1).


10.2.5 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to an appropriately sized graduated cylinder. Record the sample volume to the nearest 5 mL. Sample volumes may also be determined by weighing the container before and after extraction or filling to the mark with water.


10.3 Concentration.


10.3.1 Macro concentration.


10.3.1.1 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator so long as the requirements of section 8.2 are met.


10.3.1.2 Pour the extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the flask and column with 20-30 mL of methylene chloride to complete the quantitative transfer.


10.3.1.3 If no cleanup is to be performed on the sample, add 500 µL (0.5 mL) of isooctane to the extract to act as a keeper during concentration.


10.3.1.4 Add one or two clean boiling chips and attach a three-ball Snyder column to the K-D evaporative flask. Pre-wet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60-65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15-20 minutes. At the proper rate of evaporation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL or other determined amount, remove the K-D apparatus from the water bath and allow it to drain and cool for at least 10 minutes.


10.3.1.5 If the extract is to be cleaned up by sulfur removal or acid back extraction, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of methylene chloride. A 5-mL syringe is recommended for this operation. Adjust the final volume to 10 mL in methylene chloride and proceed to sulfur removal (section 11.5) or acid back extraction (section 11.6). If the extract is to cleaned up using one of the other cleanup procedures or is to be injected into the GC, proceed to Kuderna-Danish micro-concentration (section 10.3.2) or nitrogen evaporation and solvent exchange (section 10.3.3).


10.3.2 Kuderna-Danish micro concentration—Add another one or two clean boiling chips to the concentrator tube and attach a two-ball micro-Snyder column. Pre-wet the Snyder column by adding about 0.5 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60-65 °C) so that the concentrator tube is partially immersed in hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5-10 minutes. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches approximately 1 mL or other required amount, remove the K-D apparatus from the water bath and allow it to drain and cool for at least 10 minutes. Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with approximately 0.2 mL of methylene chloride, and proceed to section 10.3.3 for nitrogen evaporation and solvent exchange.


10.3.3 Nitrogen evaporation and solvent exchange—Extracts to be subjected to solid-phase cleanup (SPE) are exchanged into 1.0 mL of the SPE elution solvent (section 6.7.2.2). Extracts to be subjected to Florisil® or alumina cleanups are exchanged into hexane. Extracts that have been cleaned up and are ready for analysis are exchanged into isooctane or hexane, to match the solvent used for the calibration standards.


10.3.3.1 Transfer the vial containing the sample extract to the nitrogen evaporation (blowdown) device (section 5.2.5.2). Lower the vial into a 50-55 °C water bath and begin concentrating. During the solvent evaporation process, do not allow the extract to become dry. Adjust the flow of nitrogen so that the surface of the solvent is just visibly disturbed. A large vortex in the solvent may cause analyte loss.


10.3.3.2 Solvent exchange.


10.3.3.2.1 When the volume of the liquid is approximately 500 µL, add 2 to 3 mL of the desired solvent (SPE elution solvent for SPE cleanup, hexane for Florisil or alumina, or isooctane for final injection into the GC) and continue concentrating to approximately 500 µL. Repeat the addition of solvent and concentrate once more.


10.3.3.3.2 Adjust the volume of an extract to be cleaned up by SPE, Florisil®, or alumina to 1.0 mL. Proceed to extract cleanup (section 11).


10.3.3.3 Extracts that have been cleaned up and are ready for analysis—Adjust the final extract volume to be consistent with the volume extracted and the sensitivity desired. The goal is for a full-volume sample (e.g., 1-L) to have a final extract volume of 10 mL, but other volumes may be used.


10.3.4 Transfer the concentrated extract to a vial with fluoropolymer-lined cap. Seal the vial and label with the sample number. Store in the dark at room temperature until ready for GC analysis. If GC analysis will not be performed on the same day, store the vial in the dark at ≤6 °C. Analyze the extract by GC per the procedure in section 12.


10.4 Continuous liquid/liquid extraction (CLLE).


10.4.1 Use CLLE when experience with a sample from a given source indicates an emulsion problem, or when an emulsion is encountered using SFLLE. CLLE may be used for all samples, if desired.


10.4.2 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Transfer the sample to the continuous extractor and, using a pipet, add surrogate standard spiking solution. If the sample will be used for the LCS, MS, or MSD, pipet the appropriate check sample concentrate (section 8.2.1 or 8.3.2) into the separatory funnel. Mix well. Add 60 mL of methylene chloride to the sample bottle, seal, and shake for 30 seconds to rinse the inner surface. Transfer the solvent to the extractor.


10.4.3 Repeat the sample bottle rinse with two additional 50-100 mL portions of methylene chloride and add the rinses to the extractor.


10.4.4 Add a suitable volume of methylene chloride to the distilling flask (generally 200-500 mL) and sufficient reagent water to ensure proper operation of the extractor, and extract the sample for 18-24 hours. A shorter or longer extraction time may be used if all QC acceptance criteria are met. Test and, if necessary, adjust the pH of the water to a range of 5.0-9.0 during the second or third hour of the extraction. After extraction, allow the apparatus to cool, then detach the distilling flask. Dry, concentrate, solvent exchange, and transfer the extract to a vial with fluoropolymer-lined cap, per Section 10.3.


10.4.5 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to an appropriately sized graduated cylinder. Record the sample volume to the nearest 5 mL. Sample volumes may also be determined by weighing the container before and after extraction or filling to the mark with water.


10.5 Solid-phase extraction of aqueous samples. The steps in this section address the extraction of aqueous field samples using disk-based solid-phase extraction (SPE) media, based on an ATP approved by EPA in 1995 (Reference 20). This application of SPE is distinct from that used in this method for the cleanup of sample extracts in section 11.2. Analysts must be careful not to confuse the equipment, supplies, or the procedural steps from these two different uses of SPE.



Note:

Changes to the extraction conditions described below may be made by the laboratory under the allowance for method flexibility described in section 8.1, provided that the performance requirements in section 8.2 are met. However, changes in SPE materials, formats, and solvents must meet the requirements in section 8.1.2 and its subsections.


10.5.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. If the sample contains particulates, let stand to settle out the particulates before extraction.


10.5.2 Extract the sample as follows:


10.5.2.1 Place a 90-mm standard filter apparatus on a vacuum filtration flask or manifold and attach to a vacuum source. The vacuum gauge must read at least 25 in. of mercury when all valves are closed. Position a 90-mm C18 extraction disk onto the filter screen. Wet the entire disk with methanol. To aid in filtering samples with particulates, a 1-µm glass fiber filter or Empore® Filter Aid 400 can be placed on the top of the disk and wetted with methanol. Install the reservoir and clamp. Resume vacuum to dry the disk. Interrupt the vacuum. Wash the disk and reservoir with 20 mL of methylene chloride. Resume the vacuum briefly to pull methylene chloride through the disk. Interrupt the vacuum and allow the disk to soak for about a minute. Resume vacuum and completely dry the disk.


10.5.2.2 Condition the disk with 20 mL of methanol. Apply vacuum until nearly all the solvent has passed through the disk, interrupting it while solvent remains on the disk. Allow the disk to soak for about a minute. Resume vacuum to pull most of the methanol through, but interrupting it to leave a layer of methanol on the surface of the disk. Do not allow disk to dry. For uniform flow and good recovery, it is critical the disk not be allowed to dry from now until the end of the extraction. Discard waste solvent. Rinse the disk with 20 mL of deionized water. Resume vacuum to pull most of the water through, but interrupt it to leave a layer of water on the surface of the disk. Do not allow the disk to dry. If disk does dry, recondition with methanol as above.


10.5.2.3 Add the water sample to the reservoir and immediately apply the vacuum. If particulates have settled in the sample, gently decant the clear layer into the apparatus until most of the sample has been processed. Then pour the remainder including the particulates into the reservoir. Empty the sample bottle completely. When the filtration is complete, dry the disk for three minutes. Turn off the vacuum.


10.5.3 Discard sample filtrate. Insert tube to collect the eluant. The tube should fit around the drip tip of the base. Reassemble the apparatus. Add 5.0 mL of acetone to the center of the disk, allowing it to spread evenly over the disk. Turn the vacuum on and quickly off when the filter surface nears dryness but still remains wet. Allow to soak for 15 seconds. Add 20 mL of methylene chloride to the sample bottle, seal and shake to rinse the inside of the bottle. Transfer the methylene chloride from the bottle to the filter. Resume the vacuum slowly so as to avoid splashing.


Interrupt the vacuum when the filter surface nears dryness but still remains wet. Allow disk to soak in solvent for 20 seconds. Rinse the reservoir glass and disk with 10 mL of methylene chloride. Resume vacuum slowly. Interrupt vacuum when disk is covered with solvent. Allow to soak for 20 seconds. Resume vacuum to dry the disk. Remove the sample tube.


10.5.4 Dry, concentrate, solvent exchange, and transfer the extract to a vial with fluoropolymer-lined cap, per section 10.3.


10.5.5 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to an appropriately sized graduated cylinder. Record the sample volume to the nearest 5 mL. Sample volumes may also be determined by weighing the container before and after extraction or filling to the mark with water.


11. Extract Cleanup

11.1 Cleanup may not be necessary for relatively clean samples (e.g., treated effluents, groundwater, drinking water). If particular circumstances require the use of a cleanup procedure, the laboratory may use any or all of the procedures below or any other appropriate procedure (e.g., gel permeation chromatography). However, the laboratory must first repeat the tests in sections 8.2, 8.3, and 8.4 to demonstrate that the requirements of those sections can be met using the cleanup procedure(s) as an integral part of this method. This is particularly important when the target analytes for the analysis include any of the single component pesticides in Table 2, because some cleanups have not been optimized for all of those analytes.


11.1.1 The solid-phase cartridge (section 11.2) removes polar organic compounds such as phenols.


11.1.2 The Florisil® column (section 11.3) allows for selected fractionation of the organochlorine analytes and will also eliminate polar interferences.


11.1.3 Alumina column cleanup (section 11.4) also removes polar materials.


11.1.4 Elemental sulfur, which interferes with the electron capture gas chromatography of some of the pesticides, may be removed using activated copper, or TBA sulfite. Sulfur removal (section 11.5) is required when sulfur is known or suspected to be present. Some chlorinated pesticides which also contain sulfur may be removed by this cleanup.


11.1.5 Acid back extraction (section 11.6) may be useful for cleanup of PCBs and other compounds not adversely affected by sulfuric acid.


11.2 Solid-phase extraction (SPE) as a cleanup. In order to use the C18 SPE cartridge in section 5.5.3.5 as a cleanup procedure, the sample extract must be exchanged from methylene chloride to methylene chloride:acetonitrile:hexane (50:3:47). Follow the solvent exchange steps in section 10.3.3.2 prior to attempting solid-phase cleanup.



Note:

This application of SPE is distinct from that used in this method for the extraction of aqueous samples in section 10.5. Analysts must be careful not to confuse the equipment, supplies, or procedural steps from these two different uses of SPE.


11.2.1 Setup.


11.2.1.1 Attach the VacElute Manifold (section 5.5.3.2) to a water aspirator or vacuum pump with the trap and gauge installed between the manifold and vacuum source.


11.2.1.2 Place the SPE cartridges in the manifold, turn on the vacuum source, and adjust the vacuum to 5 to 10 psi.


11.2.2 Cartridge washing—Pre-elute each cartridge prior to use sequentially with 10-mL portions each of hexane, methanol, and water using vacuum for 30 seconds after each eluting solvent. Follow this pre-elution with 1 mL methylene chloride and three 10-mL portions of the elution solvent (section 6.7.2.2) using vacuum for 5 minutes after each eluting solvent. Tap the cartridge lightly while under vacuum to dry between solvent rinses. The three portions of elution solvent may be collected and used as a cartridge blank, if desired. Finally, elute the cartridge with 10 mL each of methanol and water, using the vacuum for 30 seconds after each eluant.


11.2.3 Extract cleanup.


11.2.3.1 After cartridge washing (section 11.2.2), release the vacuum and place the rack containing the 50-mL volumetric flasks (section 5.5.3.4) in the vacuum manifold. Re-establish the vacuum at 5 to 10 psi.


11.2.3.2 Using a pipette or a 1-mL syringe, transfer 1.0 mL of extract to the SPE cartridge. Apply vacuum for five minutes to dry the cartridge. Tap gently to aid in drying.


11.2.3.3 Elute each cartridge into its volumetric flask sequentially with three 10-mL portions of the methylene chloride:acetonitrile:hexane (50:3:47) elution solvent (section 6.7.2.2), using vacuum for five minutes after each portion. Collect the eluants in the 50-mL volumetric flasks.


11.2.3.4 Release the vacuum and remove the 50-mL volumetric flasks.


11.2.3.5 Concentrate the eluted extracts per Section 10.3.


11.3 Florisil®. In order to use Florisil cleanup, the sample extract must be exchanged from methylene chloride to hexane. Follow the solvent exchange steps in section 10.3.3.2 prior to attempting Florisil® cleanup.



Note:

Alternative formats for this cleanup may be used by the laboratory, including cartridges containing Florisil®. If an alternative format is used, consult the manufacturer’s instructions and develop a formal documented procedure to replace the steps in section 11.3 of this method and demonstrate that the alternative meets the relevant quality control requirements of this method.


11.3.1 If the chromatographic column does not contain a frit at the bottom, place a small plug of pre-cleaned glass wool in the column (section 5.2.4) to retain the Florisil®. Place the mass of Florisil® (nominally 20 g) predetermined by calibration (section 7.8 and Table 6) in a chromatographic column. Tap the column to settle the Florisil® and add 1 to 2 cm of granular anhydrous sodium sulfate to the top.


11.3.2 Add 60 mL of hexane to wet and rinse the sodium sulfate and Florisil®. Just prior to exposure of the sodium sulfate layer to the air, stop the elution of the hexane by closing the stopcock on the chromatographic column. Discard the eluant.


11.3.3 Transfer the concentrated extract (section 10.3.3) onto the column. Complete the transfer with two 1-mL hexane rinses, drawing the extract and rinses down to the level of the sodium sulfate.


11.3.4 Place a clean 500-mL K-D flask and concentrator tube under the column. Elute Fraction 1 with 200 mL of 6% (v/v) ethyl ether in hexane at a rate of approximately 5 mL/min. Remove the K-D flask and set it aside for later concentration. Elute Fraction 2 with 200 mL of 15% (v/v) ethyl ether in hexane into a second K-D flask. Elute Fraction 3 with 200 mL of 50% (v/v) ethyl ether in hexane into a third K-D flask. The elution patterns for the pesticides and PCBs are shown in Table 6.


11.3.5 Concentrate the fractions as in Section 10.3, except use hexane to prewet the column and set the water bath at about 85 °C. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with hexane. Adjust the volume of Fraction 1 to approximately 10 mL for sulfur removal (Section 11.5), if required; otherwise, adjust the volume of the fractions to 10 mL, 1.0 mL, or other volume needed for the sensitivity desired. Analyze the concentrated extract by gas chromatography (Section 12).


11.4 Alumina. The sample extract must be exchanged from methylene chloride to hexane. Follow the solvent exchange steps in section 10.3.3.2 prior to attempting alumina cleanup.


11.4.1 If the chromatographic column does not contain a frit at the bottom, place a small plug of pre-cleaned glass wool in the chromatographic column (section 5.2.4) to retain the alumina. Add 10 g of alumina (section 6.7.3) on top of the plug. Tap the column to settle the alumina. Place 1-2 g of anhydrous sodium sulfate on top of the alumina.


11.4.2 Close the stopcock and fill the column to just above the sodium sulfate with hexane. Add 25 mL of hexane. Open the stopcock and adjust the flow rate of hexane to approximately 2 mL/min. Do not allow the column to go dry throughout the elutions.


11.4.3 When the level of the hexane is at the top of the column, quantitatively transfer the extract to the column. When the level of the extract is at the top of the column, slowly add 25 mL of hexane and elute the column to the level of the sodium sulfate. Discard the hexane.


11.4.4 Place a K-D flask (section 5.2.5.1.2) under the column and elute the pesticides with approximately 150 mL of hexane:ethyl ether (80:20 v/v). It may be necessary to adjust the volume of elution solvent for slightly different alumina activities.


11.4.5 Concentrate the extract per section 10.3.


11.5 Sulfur removal—Elemental sulfur will usually elute in Fraction 1 of the Florisil® column cleanup. If Florisil® cleanup is not used, or to remove sulfur from any of the Florisil® fractions, use one of the sulfur removal procedures below. These procedures may be applied to extracts in hexane, ethyl ether, or methylene chloride.



Note:

Separate procedures using copper or TBA sulfite are provided in this section for sulfur removal. They may be used separately or in combination, if desired.


11.5.1 Removal with copper (Reference 15).



Note:

Some of the analytes in Table 2 are not amenable to sulfur removal with copper (e.g., atrazine and diazinon). Therefore, before using copper to remove sulfur from an extract that will be analyzed for any of the non-PCB analytes in Table 2, the laboratory must demonstrate that the analytes can be extracted from an aqueous sample matrix that contains sulfur and recovered from an extract treated with copper. Acceptable performance can be demonstrated through the preparation and analysis of a matrix spike sample that meets the QC requirements for recovery.


11.5.1.1 Quantitatively transfer the extract to a 40- to 50-mL flask or bottle. If there is evidence of water in the K-D or round-bottom flask after the transfer, rinse the flask with small portions of hexane:acetone (40:60) and add to the flask or bottle. Mark and set aside the concentration flask for future use.


11.5.1.2 Add 10-20 g of granular anhydrous sodium sulfate to the flask. Swirl to dry the extract.


11.5.1.3 Add activated copper (section 6.7.4.1.4) and allow to stand for 30-60 minutes, swirling occasionally. If the copper does not remain bright, add more and swirl occasionally for another 30-60 minutes.


11.5.1.4 After drying and sulfur removal, quantitatively transfer the extract to a nitrogen-evaporation vial or tube and proceed to section 10.3.3 for nitrogen evaporation and solvent exchange, taking care to leave the sodium sulfate and copper foil in the flask.


11.5.2 Removal with TBA sulfite.


11.5.2.1 Using small volumes of hexane, quantitatively transfer the extract to a 40- to 50-mL centrifuge tube with fluoropolymer-lined screw cap.


11.5.2.2 Add 1-2 mL of TBA sulfite reagent (section 6.7.4.2.4), 2-3 mL of 2-propanol, and approximately 0.7 g of sodium sulfite (section 6.7.4.2.2) crystals to the tube. Cap and shake for 1-2 minutes. If the sample is colorless or if the initial color is unchanged, and if clear crystals (precipitated sodium sulfite) are observed, sufficient sodium sulfite is present. If the precipitated sodium sulfite disappears, add more crystalline sodium sulfite in approximately 0.5-g portions until a solid residue remains after repeated shaking.


11.5.2.3 Add 5-10 mL of reagent water and shake for 1-2 minutes. Centrifuge to settle the solids.


11.5.2.4 Quantitatively transfer the hexane (top) layer through a small funnel containing a few grams of granular anhydrous sodium sulfate to a nitrogen-evaporation vial or tube and proceed to section 10.3.3 for micro-concentration and solvent exchange.


11.6 Acid back extraction (section 6.1.2).


11.6.1 Quantitatively transfer the extract (section 10.3.1.5) to a 250-mL separatory funnel.


11.6.2 Partition the extract against 50 mL of sulfuric acid solution (section 6.1.2). Discard the aqueous layer. Repeat the acid washing until no color is visible in the aqueous layer, to a maximum of four washings.


11.6.3 Partition the extract against 50 mL of sodium chloride solution (section 6.7.5). Discard the aqueous layer.


11.6.4 Proceed to section 10.3.3 for micro-concentration and solvent exchange.


12. Gas Chromatography

12.1 Establish the same operating conditions used in section 7.1 for instrument calibration.


12.2 If the internal standard calibration procedure is used, add the internal standard solution (section 6.9.3) to the extract as close as possible to the time of injection to minimize the possibility of loss by evaporation, adsorption, or reaction. For example, add 1 µL of 10 µg/mL internal standard solution into the extract, assuming no dilutions. Mix thoroughly.


12.3 Simultaneously inject an appropriate volume of the sample extract or standard solution onto both columns, using split, splitless, solvent purge, large-volume, or on-column injection. Alternatively, if using a single-column GC configuration, inject an appropriate volume of the sample extract or standard solution onto each GC column independently. If the sample is injected manually, the solvent-flush technique should be used. The injection volume depends upon the technique used and the sensitivity needed to meet MDLs or reporting limits for regulatory compliance. Injection volumes must be the same for all extracts. Record the volume injected to the nearest 0.05 µL.


12.4 Set the data system or GC control to start the temperature program upon sample injection, and begin data collection after the solvent peak elutes. Set the data system to stop data collection after the last analyte is expected to elute and to return the column to the initial temperature.


12.5 Perform all qualitative and quantitative measurements as described in Sections 14 and 15. When standards and extracts are not being used for analyses, store them refrigerated at
13. System and Laboratory Performance

13.1 At the beginning of each shift during which standards or extracts are analyzed, GC system performance and calibration must be verified for all analytes and surrogates on both column/detector systems. Adjustment and/or recalibration (per section 7) are performed until all performance criteria are met. Only after all performance criteria are met may samples, blanks and other QC samples, and standards be analyzed.


13.2 Inject an aliquot of the calibration verification standard (section 6.8.4) on both columns. Inject an aliquot of each of the multi-component standards.


13.3 Retention times—The absolute retention times of the peak maxima shall be within ±2 seconds of the retention times in the calibration verification (section 7.8).


13.4 GC resolution—Resolution is acceptable if the valley height between two peaks (as measured from the baseline) is less than 40% of the shorter of the two peaks.


13.4.1 DB-608 column—DDT and endrin aldehyde


13.4.2 DB-1701 column—alpha and gamma chlordane



Note:

If using other GC columns or stationary phases, these resolution criteria apply to these four target analytes and any other closely eluting analytes on those other GC columns.


13.5 Decomposition of DDT and endrin—If DDT, endrin, or their breakdown products are to be determined, this test must be performed prior to calibration verification (section 13.6). DDT decomposes to DDE and DDD. Endrin decomposes to endrin aldehyde and endrin ketone.


13.5.1 Inject 1 µL of the DDT and endrin decomposition solution (section 6.8.7). As noted in section 6.8.7, other injection volumes may be used as long as the concentrations of DDT and endrin in the solution are adjusted to introduce the masses of the two analytes into the instrument that are listed in section 6.8.7.


13.5.2 Measure the areas of the peaks for DDT, DDE, DDD, endrin, endrin aldehyde, and endrin ketone in the chromatogram and calculate the percent breakdown as shown in the equations below:



13.5.3 Both the % breakdown of DDT and of endrin must be less than 20%, otherwise the system is not performing acceptably for DDT and endrin. In this case, repair the GC column system that failed and repeat the performance tests (sections 13.2 to 13.6) until the specification is met.



Note:

DDT and endrin decomposition are usually caused by accumulations of particulates in the injector and in the front end of the column. Cleaning and silanizing the injection port liner, and breaking off a short section of the front end of the column will usually eliminate the decomposition problem. Either of these corrective actions may affect retention times, GC resolution, and calibration linearity.


13.6 Calibration verification.


13.6.1 Compute the percent recovery of each analyte and of the coeluting analytes, based on the initial calibration data (section 7.5 or 7.6).


13.6.2 For each analyte or for coeluting analytes, compare the concentration with the limits for calibration verification in Table 4. For coeluting analytes, use the coeluting analyte with the least restrictive specification (the widest range). For analytes in Table 2 not listed in Table 4, QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 13 and 14). If the recoveries for all analytes meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may continue. If, however, any recovery falls outside the calibration verification range, system performance is unacceptable for that analyte. If this occurs, repair the system and repeat the test (section 13.6), or prepare a fresh calibration standard and repeat the test, or recalibrate (section 7). See Section 8.1.7 for information on repeated test failures.


13.7 Laboratory control sample.


13.7.1 Analyze the extract of the LCS (section 6.8.3) extracted with each sample batch (Section 8.4). See Section 8.4 for criteria acceptance of the LCS.


13.7.2 It is suggested, but not required, that the laboratory update statements of data quality. Add results that pass the specifications in section 13.7.3 to initial (section 8.7) and previous ongoing data. Update QC charts to form a graphic representation of continued laboratory performance. Develop a statement of laboratory data quality for each analyte by calculating the average percent recovery (R) and the standard deviation of percent recovery, sr. Express the accuracy as a recovery interval from R − 2sr to R + 2sr. For example, if R = 95% and sr = 5%, the accuracy is 85 to 105%.


13.8 Internal standard response—If internal standard calibration is used, verify that detector sensitivity has not changed by comparing the response (area or height) of each internal standard in the sample, blank, LCS, MS, and MSD to the response in calibration verification (section 6.8.3). The peak area or height of the internal standard should be within 50% to 200% (
1/2 to 2x) of its respective peak area or height in the verification standard. If the area or height is not within this range, compute the concentration of the analytes using the external standard method (section 7.5). If the analytes are affected, re-prepare and reanalyze the sample, blank, LCS, MS, or MSD, and repeat the pertinent test.


14. Qualitative Identification

14.1 Identification is accomplished by comparison of data from analysis of a sample, blank, or other QC sample with data from calibration verification (section 7.7.1 or 13.5), and with data stored in the retention-time and calibration libraries (section 7.7). The retention time window is determined as described in section 14.2. Identification is confirmed when retention time agrees on both GC columns, as described below. Alternatively, GC/MS identification may be used to provide another means of identification.


14.2 Establishing retention time windows.


14.2.1 Using the data from the multi-point initial calibration (section 7.4), determine the retention time in decimal minutes (not minutes:seconds) of each peak representing a single-component target analyte on each column/detector system. For the multi-component analytes, use the retention times of the five largest peaks in the chromatograms on each column/detector system.


14.2.2 Calculate the standard deviation of the retention times for each single-component analyte on each column/detector system and for the three to five exclusive (unique large) peaks for each multi-component analyte.


14.2.3 Define the width of the retention time window as three times that standard deviation. Establish the center of the retention time window for each analyte by using the absolute retention time for each analyte from the calibration verification standard at the beginning of the analytical shift. For samples run during the same shift as an initial calibration, use the retention time of the mid-point standard of the initial calibration. If the calculated RT window is less than 0.02 minutes, then use 0.02 minutes as the window.



Note:

Procedures for establishing retention time windows from other sources may be employed provided that they are clearly documented and provide acceptable performance. Such performance may be evaluated using the results for the spiked QC samples described in this method, such as laboratory control samples and matrix spike samples.


14.2.4 The retention time windows must be recentered when a new GC column is installed or if a GC column has been shortened during maintenance to a degree that the retention times of analytes in the calibration verification standard have shifted close to the lower limits of the established retention time windows.


14.2.5 RT windows should be checked periodically by examining the peaks in spiked samples such as the LCS or MS/MSD to confirm that peaks for known analytes are properly identified.


14.2.6 If the retention time of an analyte in the calibration (Section 7.4) varies by more than 5 seconds across the calibration range as a function of the concentration of the standard, using the standard deviation of the retention times (section 14.2.3) to set the width of the retention time window may not adequately serve to identify the analyte in question under routine conditions. In such cases, data from additional analyses of standards may be required to adequately model the chromatographic behavior of the analyte.


14.3 Identifying the analyte in a sample.


14.3.1 In order to identify a single-component analyte from analysis of a sample, blank, or other QC sample, the peak representing the analyte must fall within its respective retention time windows on both column/detector systems (as defined in section 14.2). That identification is further supported by the comparison of the numerical results on both columns, as described in section 15.7.


14.3.2 In order to identify a multi-component analyte, pattern matching (fingerprinting) may be used, or the three to five exclusive (unique and largest) peaks for that analyte must fall within their respective retention time windows on both column/detector systems (as defined in section 14.2). That identification is further supported by the comparison of the numerical results on both columns, as described in section 15.7. Alternatively, GC/MS identification may be used. Differentiation among some of the Aroclors may require evaluation of more than five peaks to ensure correct identification.


14.4 GC/MS confirmation. When the concentration of an analyte is sufficient and the presence or identity is suspect, its presence should be confirmed by GC/MS. In order to match the sensitivity of the GC/ECD, confirmation would need to be by GC/MS-SIM, or the estimated concentration would need to be 100 times higher than the GC/ECD calibration range. The extract may be concentrated by an additional amount to allow a further attempt at GC/MS confirmation.


14.5 Additional information that may aid the laboratory in the identification of an analyte. The occurrence of peaks eluting near the retention time of an analyte of interest increases the probability of a false positive for the analyte. If the concentration is insufficient for confirmation by GC/MS, the laboratory may use the cleanup procedures in this method (section 11) on a new sample aliquot to attempt to remove the interferent. After attempts at cleanup are exhausted, the following steps may be helpful to assure that the substance that appears in the RT windows on both columns is the analyte of interest.


14.5.1 Determine the consistency of the RT data for the analyte on each column. For example, if the RT is very stable (i.e., varies by no more than a few seconds) for the calibration, calibration verification, blank, LCS, and MS/MSD, the RT for the analyte of interest in the sample should be within this variation regardless of the window established in Section 14.2. If the analyte is not within this variation on both columns, it is likely not present.


14.5.2 The possibility exists that the RT for the analyte in a sample could shift if extraneous materials are present. This possibility may be able to be confirmed or refuted by the behavior of the surrogates in the sample. If multiple surrogates are used that span the length of the chromatographic run, the RTs for the surrogates on both columns are consistent with their RTs in calibration, calibration verification, blank, LCS, and MS/MSD, it is unlikely that the RT for the analyte of interest has shifted.


14.5.3 If the RT for the analyte is shifted slightly later on one column and earlier on the other, and the surrogates have not shifted, it is highly unlikely that the analyte is present, because shifts nearly always occur in the same direction on both columns.


15. Quantitative Determination

15.1 External standard quantitation—Calculate the concentration of the analyte in the extract using the calibration curve or average calibration factor determined in calibration (section 7.5.2) and the following equation:



where:

Cex = Concentration of the analyte in the extract (ng/mL)

As = Peak height or area for the analyte in the standard or sample

CF = Calibration factor, as defined in Section 7.5.1

15.2 Internal standard quantitation—Calculate the concentration of the analyte in the extract using the calibration curve or average response factor determined in calibration (section 7.6.2) and the following equation:



where:

Cex = Concentration of the analyte in the extract (ng/mL)

As = Peak height or area for the analyte in the standard or sample

Cis = Concentration of the internal standard (ng/mL)

Ais = Area of the internal standard

RF = Response factor, as defined in section 7.6.1

15.3 Calculate the concentration of the analyte in the sample using the concentration in the extract, the extract volume, the sample volume, and the dilution factor, per the following equation:



where:

Cs = Concentration of the analyte in the sample (µg/L)

Vex = Final extract volume (mL)

Cex = Concentration in the extract (ng/mL)

Vs = Volume of sample (L)

DF = Dilution factor

and the factor of 1,000 in the denominator converts the final units from ng/L to µg/L

15.4 If the concentration of any target analyte exceeds the calibration range, either extract and analyze a smaller sample volume, or dilute and analyze the diluted extract.


15.5 Quantitation of multi-component analytes.


15.5.1 PCBs as Aroclors. Quantify an Aroclor by comparing the sample chromatogram to that of the most similar Aroclor standard as indicated in section 14.3.2. Compare the responses of 3 to 5 major peaks in the calibration standard for that Aroclor with the peaks observed in the sample extract. The amount of Aroclor is calculated using the individual calibration factor for each of the 3 to 5 characteristic peaks chosen in section 7.5.1. Determine the concentration of each of the characteristic peaks, using the average calibration factor calculated for that peak in section 7.5.2, and then those 3 to 5 concentrations are averaged to determine the concentration of that Aroclor.


15.5.2 Other multi-component analytes. Quantify any other multi-component analytes (technical chlordane or toxaphene) using the same peaks used to develop the average calibration factors in section 7.5.2. Determine the concentration of each of the characteristic peaks, and then the concentrations represented by those characteristic peaks are averaged to determine the concentration of the analyte. Alternatively, for toxaphene, the analyst may determine the calibration factor in section 7.5.2 by summing the areas of all of the peaks for the analyte and using the summed of the peak areas in the sample chromatogram to determine the concentration. However, the approach used for toxaphene must be the same for the calibration and the sample analyses.


15.6 Reporting of results. As noted in section 1.6.1, EPA has promulgated this method at 40 CFR part 136 for use in wastewater compliance monitoring under the National Pollutant Discharge Elimination System (NPDES). The data reporting practices described here are focused on such monitoring needs and may not be relevant to other uses of the method.


15.6.1 Report results for wastewater samples in µg/L without correction for recovery. (Other units may be used if required by in a permit.) Report all QC data with the sample results.


15.6.2 Reporting level. Unless specified otherwise by a regulatory authority or in a discharge permit, results for analytes that meet the identification criteria are reported down to the concentration of the ML established by the laboratory through calibration of the instrument (see section 7.5 or 7.6 and the glossary for the derivation of the ML). EPA considers the terms “reporting limit,” “quantitation limit,” and “minimum level” to be synonymous.


15.6.2.1 Report the lower result from the two columns (see section 15.7 below) for each analyte in each sample or QC standard at or above the ML to 3 significant figures. Report a result for each analyte in each sample or QC standard below the ML as “

15.6.2.2 In addition to reporting results for samples and blank(s) separately, the concentration of each analyte in a blank or field blank associated with that sample may be subtracted from the result for that sample, but only if requested or required by a regulatory authority or in a permit. In this case, both the sample result and the blank results must be reported together.


15.6.2.3 Report the result for an analyte in a sample or extract that has been diluted at the least dilute level at which the peak area is within the calibration range (i.e., above the ML for the analyte) and the MS/MSD recovery and RPD are within their respective QC acceptance criteria (Table 4). This may require reporting results for some analytes from different analyses. Results for each analyte in MS/MSD samples should be reported from the same GC column as used to report the results for that analyte in the unspiked sample. If the MS/MSD recoveries and RPDs calculated in this manner do not meet the acceptance criteria in Table 4, the analyst may use the results from the other GC column to determine if the MS/MSD results meet the acceptance criteria. If such a situation occurs, the results for the sample should be recalculated using the same GC column data as used for the MS/MSD samples, and reported with appropriate annotations that alert the data user of the issue.


15.6.2.4 Results from tests performed with an analytical system that is not in control (i.e., that does not meet acceptance criteria for all of QC tests in this method) must not be reported or otherwise used for permitting or regulatory compliance purposes, but do not relieve a discharger or permittee of reporting timely results. See section 8.1.7 for dispositions of failures. If the holding time would be exceeded for a re-analysis of the sample, the regulatory/control authority should be consulted for disposition.


15.6.3 Analyze the sample by GC/MS or on a third column when analytes have co-eluted or interfere with determination on both columns.



Note:

Dichlone and kepone do not elute from the DB-1701 column and must be confirmed on a DB-5 column, or by GC/MS.


15.7 Quantitative information that may aid in the confirmation of the presence of an analyte.


15.7.1 As noted in Section 14.3, the relative agreement between the numerical results from the two GC columns may be used to support the identification of the target analyte by providing evidence that co-eluting interferences are not present at the retention time of the target analyte. Calculate the percent difference (%D) between the results for the analyte from both columns, as follows:



In general, if the %D of the two results is less than 50% (e.g., a factor of 2), then the pesticide is present. This %D is generous and allows for the pesticide that has the largest measurement error.



Note:

Laboratories may employ metrics less than 50% for this comparison, including those specified in other analytical methods for these pesticides (e.g., CLP or SW-846).


15.7.2 If the amounts do not agree, and the RT data indicate the presence of the analyte (per Section 14), it is likely that a positive interference is present on the column that yielded the higher result. That interferent may be represented by a separate peak on the other column that does not coincide with the retention time of any of the target analytes. If the interfering peak is evident on the other column, report the result from that column and advise the data user that the interference resulted in a %D value greater than 50%. If an interferent is not identifiable on the second column, then the results must be reported as “not detected” at the lower concentration. In this event, the pesticide is not confirmed and the reporting limit is elevated. See section 8.1.7 for disposition of problem results.



Note:

The resulting elevation of the reporting limit may not meet the requirements for compliance monitoring and the use of additional cleanup procedures may be required.


16. Analysis of Complex Samples

16.1 Some samples may contain high levels (greater than 1 µg/L) of the analytes of interest, interfering analytes, and/or polymeric materials. Some samples may not concentrate to 1.0 mL (section 10.3.3.3.2); others may overload the GC column and/or detector.


16.2 When an interference is known or suspected to be present, the laboratory should attempt to clean up the sample extract using the SPE cartridge (section 11.2), by Florisil® (Section 11.3), Alumina (Section 11.4), sulfur removal (section 11.5), or another clean up procedure appropriate to the analytes of interest. If these techniques do not remove the interference, the extract is diluted by a known factor and reanalyzed (section 12). Dilution until the extract is lightly colored is preferable. Typical dilution factors are 2, 5, and 10.


16.3 Recovery of surrogate(s)—In most samples, surrogate recoveries will be similar to those from reagent water. If surrogate recovery is outside the limits developed in Section 8.6, re-extract and reanalyze the sample if there is sufficient sample and if it is within the 7-day extraction holding time. If surrogate recovery is still outside this range, extract and analyze one-tenth the volume of sample to overcome any matrix interference problems. If a sample is highly colored or suspected to be high in concentration, a 1-L sample aliquot and a 100-mL sample aliquot could be extracted simultaneously and still meet the holding time criteria, while providing information about a complex matrix.


16.4 Recovery of the matrix spike and matrix spike duplicate (MS/MSD)—In most samples, MS/MSD recoveries will be similar to those from reagent water. If either the MS or MSD recovery is outside the range specified in Section 8.3.3, one-tenth the volume of sample is spiked and analyzed. If the matrix spike recovery is still outside the range, the result for the unspiked sample may not be reported or used for permitting or regulatory compliance purposes. See Section 8.1.7 for dispositions of failures. Poor matrix spike recovery does not relieve a discharger or permittee of reporting timely results.


17. Method Performance

17.1 This method was tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 4x MDL to 1000x MDL with the following exceptions: Chlordane recovery at 4x MDL was low (60%); Toxaphene recovery was demonstrated linear over the range of 10x MDL to 1000x MDL (Reference 3).


17.2 The 1984 version of this method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations (Reference 2). Concentrations used in the study ranged from 0.5 to 30 µg/L for single-component pesticides and from 8.5 to 400 µg/L for multi-component analytes. These data are for a subset of analytes described in the current version of the method.


17.3 During the development of Method 1656, a similar EPA procedure for the organochlorine pesticides, single-operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the analyte and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 5.


18. Pollution Prevention

18.1 Pollution prevention encompasses any technique that reduces or eliminates the quantity or toxicity of waste at the point of generation. Many opportunities for pollution prevention exist in laboratory operations. EPA has established a preferred hierarchy of environmental management techniques that places pollution prevention as the management option of first choice. Whenever feasible, the laboratory should use pollution prevention techniques to address waste generation. When wastes cannot be reduced at the source, the Agency recommends recycling as the next best option.


18.2 The analytes in this method are used in extremely small amounts and pose little threat to the environment when managed properly. Standards should be prepared in volumes consistent with laboratory use to minimize the disposal of excess volumes of expired standards. This method utilizes significant quantities of methylene chloride. Laboratories are encouraged to recover and recycle this and other solvents during extract concentration.


18.3 For information about pollution prevention that may be applied to laboratories and research institutions, consult “Less is Better: Laboratory Chemical Management for Waste Reduction” (Reference 19), available from the American Chemical Society’s Department of Governmental Relations and Science Policy, 1155 16th Street NW., Washington DC 20036, 202-872-4477.


19. Waste Management

19.1 The laboratory is responsible for complying with all Federal, State, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions, and to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations. An overview of requirements can be found in Environmental Management Guide for Small Laboratories (EPA 233-B-98-001).


19.2 Samples at pH 12, are hazardous and must be handled and disposed of as hazardous waste, or neutralized and disposed of in accordance with all federal, state, and local regulations. It is the laboratory’s responsibility to comply with all federal, state, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions. The laboratory using this method has the responsibility to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations. For further information on waste management, see “The Waste Management Manual for Laboratory Personnel,” also available from the American Chemical Society at the address in section 18.3.


19.3 Many analytes in this method decompose above 500 °C. Low-level waste such as absorbent paper, tissues, animal remains, and plastic gloves may be burned in an appropriate incinerator. Gross quantities of neat or highly concentrated solutions of toxic or hazardous chemicals should be packaged securely and disposed of through commercial or governmental channels that are capable of handling toxic wastes.


19.4 For further information on waste management, consult The Waste Management Manual for Laboratory Personnel and Less is Better-Laboratory Chemical Management for Waste Reduction, available from the American Chemical Society’s Department of Government Relations and Science Policy, 1155 16th Street NW., Washington, DC 20036, 202-872-4477.


20. References

1. “Determination of Pesticides and PCBs in Industrial and Municipal Wastewaters,” EPA 600/4-82-023, National Technical Information Service, PB82-214222, Springfield, Virginia 22161, April 1982.

2. “EPA Method Study 18 Method 608-Organochlorine Pesticides and PCBs,” EPA 600/4-84-061, National Technical Information Service, PB84-211358, Springfield, Virginia 22161, June 1984.

3. “Method Detection Limit and Analytical Curve Studies, EPA Methods 606, 607, and 608,” Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.

4. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practice for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.

5. Giam, C.S., Chan, H.S., and Nef, G.S. “Sensitive Method for Determination of Phthalate Ester Plasticizers in Open-Ocean Biota Samples,” Analytical Chemistry, 47:2225 (1975).

6. Giam, C.S. and Chan, H.S. “Control of Blanks in the Analysis of Phthalates in Air and Ocean Biota Samples,” U.S. National Bureau of Standards, Special Publication 442, pp. 701-708, 1976.

7. Solutions to Analytical Chemistry Problems with Clean Water Act Methods, EPA 821-R-07-002, March 2007.

8. “Carcinogens-Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

9. “Occupational Exposure to Hazardous Chemicals in Laboratories,” (29 CFR 1910.1450), Occupational Safety and Health Administration, OSHA.

10. 40 CFR 136.6(b)(4)(j).

11. Mills, P.A. “Variation of Florisil Activity: Simple Method for Measuring Absorbent Capacity and Its Use in Standardizing Florisil Columns,” Journal of the Association of Official Analytical Chemists, 51:29, (1968).

12. 40 CFR 136.6(b)(2)(i).

13. Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes in Wastewater and Drinking Water (EPA-821-B-98-003) March 1999.

14. Methods 4500 Cl F and 4500 Cl G, Standard Methods for the Examination of Water and Wastewater, published jointly by the American Public Health Association, American Water Works Association, and Water Environment Federation, 1015 Fifteenth St., Washington, DC 20005, 20th Edition, 2000.

15. “Manual of Analytical Methods for the Analysis of Pesticides in Human and Environmental Samples,” EPA-600/8-80-038, U.S. Environmental Protection Agency, Health Effects Research Laboratory, Research Triangle Park, North Carolina.

16. USEPA, 2000, Method 1656 Organo-Halide Pesticides In Wastewater, Soil, Sludge, Sediment, and Tissue by GC/HSD, EPA-821-R-00-017, September 2000.

17. USEPA, 2010, Method 1668C Chlorinated Biphenyl Congeners in Water, Soil, Sediment, Biosolids, and Tissue by HRGC/HRMS, EPA-820-R-10-005, April 2010.

18. USEPA, 2007, Method 1699: Pesticides in Water, Soil, Sediment, Biosolids, and Tissue by HRGC/HRMS, EPA-821-R-08-001, December 2007.

19. “Less is Better,” American Chemical Society on-line publication, http://www.acs.org/content/dam/acsorg/about/governance/committees/chemicalsafety/publications/less-is-better.pdf.

20. EPA Method 608 ATP 3M0222, An alternative test procedure for the measurement of organochlorine pesticides and polychlorinated biphenyls in waste water. Federal Register, Vol. 60, No. 148 August 2, 1995.

21. Tables

Table 1—Pesticides
1

Analyte
CAS No.
MDL
2

(ng/L)
ML
3

(ng/L)
Aldrin309-00-2412
alpha-BHC319-84-639
beta-BHC319-85-7618
delta-BHC319-86-8927
gamma-BHC (Lindane)58-89-9412
alpha-Chlordane
4		5103-71-91442
gamma-Chlordane
4		5103-74-21442
4,4′-DDD72-54-81133
4,4′-DDE72-55-9412
4,4′-DDT50-29-31236
Dieldrin60-57-126
Endosulfan I959-98-81442
Endosulfan II33213-65-9412
Endosulfan sulfate1031-07-866198
Endrin72-20-8618
Endrin aldehyde7421-93-42370
Heptachlor76-44-839
Heptachlor epoxide1024-57-383249


1 All analytes in this table are Priority Pollutants (40 CFR part 423, appendix A).


2 40 CFR part 136, appendix B, June 30, 1986.


3 ML = Minimum Level—see Glossary for definition and derivation, calculated as 3 times the MDL.


4 MDL based on the MDL for Chlordane.


Table 2—Additional Analytes

Analyte
CAS No.
MDL
3

(ng/L)
ML
4

(ng/L)
Acephate30560-19-1
Alachlor15972-60-8
Atrazine1912-24-9
Benfluralin (Benefin)1861-40-1
Bromacil314-40-9
Bromoxynil octanoate1689-99-2
Butachlor23184-66-9
Captafol2425-06-1
Captan133-06-2
Carbophenothion (Trithion)786-19-6
Chlorobenzilate510-15-6
Chloroneb (Terraneb)2675-77-6
Chloropropylate (Acaralate)5836-10-2
Chlorothalonil1897-45-6
Cyanazine21725-46-2
DCPA (Dacthal)1861-32-1
2,4′-DDD53-19-0
2,4′-DDE3424-82-6
2,4′-DDT789-02-6
Diallate (Avadex)2303-16-4
1,2-Dibromo-3-chloropropane (DBCP)96-12-8
Dichlone117-80-6
Dichloran99-30-9
Dicofol115-32-2
Endrin ketone53494-70-5
Ethalfluralin (Sonalan)55283-68-6
Etridiazole2593-15-9
Fenarimol (Rubigan)60168-88-9
Hexachlorobenzene
1		118-74-1
Hexachlorocyclopentadiene
1		77-47-4
Isodrin465-73-6
Isopropalin (Paarlan)33820-53-0
Kepone143-50-0
Methoxychlor72-43-5
Metolachlor51218-45-2
Metribuzin21087-64-9
Mirex2385-85-5
Nitrofen (TOK)1836-75-5
cis-Nonachlor5103-73-1
trans-Nonachlor39765-80-5
Norfluorazon27314-13-2
Octachlorostyrene29082-74-4
Oxychlordane27304-13-8
PCNB (Pentachloronitrobenzene)82-68-8
Pendamethalin (Prowl)40487-42-1
cis-Permethrin61949-76-6
trans-Permethrin61949-77-7
Perthane (Ethylan)72-56-0
Propachlor1918-16-7
Propanil709-98-8
Propazine139-40-2
Quintozene82-68-8
Simazine122-34-9
Strobane8001-50-1
Technazene117-18-0
Technical Chlordane
2
Terbacil5902-51-2
Terbuthylazine5915-41-3
Toxaphene
1		8001-35-2240720
Trifluralin1582-09-8
PCB-1016
1		12674-11-2
PCB-1221
1		11104-28-2
PCB-1232
1		11141-16-5
PCB-1242
1		53469-21-96595
PCB-1248
1		12672-29-6
PCB-1254
1		11097-69-1
PCB-1260
1		11096-82-5
PCB-126811100-14-4


1 Priority Pollutants (40 CFR part 423, appendix A).


2 Technical Chlordane may be used in cases where historical reporting has only been for this form of Chlordane.


3 40 CFR part 136, appendix B, June 30, 1986.


4 ML = Minimum Level—see Glossary for definition and derivation, calculated as 3 times the MDL.


Table 3—Example Retention Times
1

Analyte
Retention time

(min)
2
DB-608
DB-1701
Acephate5.03(
3)
Trifluralin5.166.79
Ethalfluralin5.286.49
Benfluralin5.536.87
Diallate-A7.156.23
Diallate-B7.426.77
alpha-BHC8.147.44
PCNB9.037.58
Simazine9.069.29
Atrazine9.129.12
Terbuthylazine9.179.46
gamma-BHC (Lindane)9.529.91
beta-BHC9.8611.90
Heptachlor10.6610.55
Chlorothalonil10.6610.96
Dichlone10.80(
4)
Terbacil11.1112.63
delta-BHC11.2012.98
Alachlor11.5711.06
Propanil11.6014.10
Aldrin11.8411.46
DCPA12.1812.09
Metribuzin12.8011.68
Triadimefon12.9913.57
Isopropalin13.0613.37
Isodrin13.4711.12
Heptachlor epoxide13.9712.56
Pendamethalin14.2113.46
Bromacil14.39(
3)
alpha-Chlordane14.6314.20
Butachlor15.0315.69
gamma-Chlordane15.2414.36
Endosulfan I15.2513.87
4,4′-DDE16.3414.84
Dieldrin16.4115.25
Captan16.8315.43
Chlorobenzilate17.5817.28
Endrin17.8015.86
Nitrofen (TOK)17.8617.47
Kepone17.92(
3 5)
4,4′-DDD18.4317.77
Endosulfan II18.4518.57
Bromoxynil octanoate18.8518.57
4,4′-DDT19.4818.32
Carbophenothion19.6518.21
Endrin aldehyde19.7219.18
Endosulfan sulfate20.2120.37
Captafol22.5121.22
Norfluorazon20.6822.01
Mirex22.7519.79
Methoxychlor22.8020.68
Endrin ketone23.0021.79
Fenarimol24.5323.79
cis-Permethrin25.0023.59
trans-Permethrin25.6223.92
PCB-1016
PCB-1221
PCB-1232
PCB-1242
PCB-1248
PCB-1254
PCB-1260 (5 peaks)15.4414.64
15.7315.36
16.9416.53
17.2818.70
19.1719.92
Toxaphene (5 peaks)16.6016.60
17.3717.52
18.1117.92
19.4618.73
19.6919.00


1 Data from EPA Method 1656 (Reference 16).


2 Columns: 30-m long x 0.53-mm ID fused-silica capillary; DB-608, 0.83 µm; and DB-1701, 1.0 µm.

Conditions suggested to meet retention times shown: 150 °C for 0.5 minute, 150-270 °C at 5 °C/min, and 270 °C until trans-Permethrin elutes.

Carrier gas flow rates approximately 7 mL/min.


3 Does not elute from DB-1701 column at level tested.


4 Not recovered from water at the levels tested.


5 Dichlone and Kepone do not elute from the DB-1701 column and should be confirmed on DB-5.


Table 4—QC Acceptance Criteria

Analyte
Calibration verification

(%)
Test

concentration

(µg/L)
Limit for s

(% SD)
Range for X

(%)
Range for P

(%)
Maximum

MS/MSD

RPD

(%)
Aldrin75-1252.02554-13042-14035
alpha-BHC69-1252.02849-13037-14036
beta-BHC75-1252.03839-13017-14744
delta-BHC75-1252.04351-13019-14052
gamma-BHC75-1252.02943-13032-14039
alpha-Chlordane73-12550.02455-13045-14035
gamma-Chlordane75-12550.02455-13045-14035
4,4′-DDD75-12510.03248-13031-14139
4,4′-DDE75-1252.03054-13030-14535
4,4′-DDT75-12510.03946-13725-16042
Dieldrin48-1252.04258-13036-14649
Endosulfan I75-1252.02557-14145-15328
Endosulfan II75-12510.06322-171D-20253
Endosulfan sulfate70-12510.03238-13226-14438
Endrin5-12510.04251-13030-14748
Heptachlor75-1252.02843-13034-14043
Heptachlor epoxide75-1252.02257-13237-14226
Toxaphene68-13450.03056-13041-14041
PCB-101675-12550.02461-10350-14036
PCB-122175-12550.05044-15015-17848
PCB-123275-12550.03228-19710-21525
PCB-124275-12550.02650-13939-15029
PCB-124875-12550.03258-14038-15835
PCB-125475-12550.03444-13029-14045
PCB-126075-12550.02837-1308-14038

S = Standard deviation of four recovery measurements for the DOC (section 8.2.4).

X = Average of four recovery measurements for the DOC (section 8.2.4).

P = Recovery for the LCS (section 8.4.3).

Note: These criteria were developed from data in Table 5 (Reference 2). Where necessary, limits for recovery have been broadened to assure applicability to concentrations below those in Table 5.


Table 5—Precision and Recovery as Functions of Concentration

Analyte
Recovery, X′

(µg/L)
Single analyst

precision, sr′

(µg/L)
Overall

precision, S′

(µg/L)
Aldrin0.81C + 0.040.16(X) − 0.040.20(X) − 0.01
alpha-BHC0.84C + 0.030.13(X) + 0.040.23(X) − 0.00
beta-BHC0.81C + 0.070.22(X) − 0.020.33(X) − 0.05
delta-BHC0.81C + 0.070.18(X) + 0.090.25(X) + 0.03
gamma-BHC (Lindane)0.82C − 0.050.12(X) + 0.060.22(X) + 0.04
Chlordane0.82C − 0.040.13(X) + 0.130.18(X) + 0.18
4,4′-DDD0.84C + 0.300.20(X) − 0.180.27(X) − 0.14
4,4′-DDE0.85C + 0.140.13(X) + 0.060.28(X) − 0.09
4,4′-DDT0.93C − 0.130.17(X) + 0.390.31(X) − 0.21
Dieldrin0.90C + 0.020.12(X) + 0.190.16(X) + 0.16
Endosulfan I0.97C + 0.040.10(X) + 0.070.18(X) + 0.08
Endosulfan II0.93C + 0.340.41(X) − 0.650.47(X) − 0.20
Endosulfan sulfate0.89C − 0.370.13(X) + 0.330.24(X) + 0.35
Endrin0.89C − 0.040.20(X) + 0.250.24(X) + 0.25
Heptachlor0.69C + 0.040.06(X) + 0.130.16(X) + 0.08
Heptachlor epoxide0.89C + 0.100.18(X) − 0.110.25(X) − 0.08
Toxaphene0.80C + 1.740.09(X) + 3.200.20(X) + 0.22
PCB-10160.81C + 0.500.13(X) + 0.150.15(X) + 0.45
PCB-12210.96C + 0.650.29(X) − 0.760.35(X) − 0.62
PCB-12320.91C + 10.80.21(X) − 1.930.31(X) + 3.50
PCB-12420.93C + 0.700.11(X) + 1.400.21(X) + 1.52
PCB-12480.97C + 1.060.17(X) + 0.410.25(X) − 0.37
PCB-12540.76C + 2.070.15(X) + 1.660.17(X) + 3.62
PCB-12600.66C + 3.760.22(X) − 2.370.39(X) − 4.86

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.


Table 6—Distribution of Chlorinated Pesticides and PCBs Into Florisil® Column Fractions

Analyte
Percent Recovery by Fraction
1
1
2
3
Aldrin100
alpha-BHC100
beta-BHC97
delta-BHC98
gamma-BHC (Lindane)100
Chlordane100
4,4′-DDD99
4,4′-DDE98
4,4′-DDT100
Dieldrin0100
Endosulfan I3764
Endosulfan II0791
Endosulfan sulfate00106
Endrin496
Endrin aldehyde06826
Heptachlor100
Heptachlor epoxide100
Toxaphene96
PCB-101697
PCB-122197
PCB-1232954
PCB-124297
PCB-1248103
PCB-125490
PCB-1260


1 Eluant composition:

Fraction 1—6% ethyl ether in hexane.

Fraction 2—15% ethyl ether in hexane.

Fraction 3—50% ethyl ether in hexane.


Table 7—Suggested Calibration Groups
1

Analyte
Calibration Group 1:
Acephate
Alachlor
Atrazine
beta-BHC
Bromoxynil octanoate
Captafol
Diallate
Endosulfan sulfate
Endrin
Isodrin
Pendimethalin (Prowl)
trans-Permethrin
Calibration Group 2:
alpha-BHC
DCPA
4,4′-DDE
4,4′-DDT
Dichlone
Ethalfluralin
Fenarimol
Methoxychlor
Metribuzin
Calibration Group 3:
gamma-BHC (Lindane)
gamma-Chlordane
Endrin ketone
Heptachlor epoxide
Isopropalin
Nitrofen (TOK)
PCNB
cis-Permethrin
Trifluralin
Callibration Group 4:
Benfluralin
Chlorobenzilate
Dieldrin
Endosulfan I
Mirex
Terbacil
Terbuthylazine
Triadimefon
Calibration Group 5:
alpha-Chlordane
Captan
Chlorothalonil
4,4′-DDD
Norfluorazon
Simazine
Calibration Group 6:
Aldrin
delta-BHC
Bromacil
Butachlor
Endosulfan II
Heptachlor
Kepone
Calibration Group 7:
Carbophenothion
Chloroneb
Chloropropylate
DBCP
Dicofol
Endrin aldehyde
Etridiazone
Perthane
Propachlor
Propanil
Propazine


1 The analytes may be organized in other calibration groups, provided that there are no coelution problems and that all QC requirements are met.


22. Figures



23. Glossary

These definitions and purposes are specific to this method but have been conformed to common usage to the extent possible.


23.1 Units of weight and measure and their abbreviations.


23.1.1 Symbols.


°C degrees Celsius

µg microgram

µL microliter


≤ less than or equal to

> greater than

% percent

23.1.2 Abbreviations (in alphabetical order).


cm centimeter

g gram

hr hour

ID inside diameter

in. inch

L liter

M molar solution—one mole or gram molecular weight of solute in one liter of solution

mg milligram

min minute

mL milliliter

mm millimeter

N Normality—one equivalent of solute in one liter of solution

ng nanogram

psia pounds-per-square inch absolute

psig pounds-per-square inch gauge

v/v volume per unit volume

w/v weight per unit volume

23.2 Definitions and acronyms (in alphabetical order)


Analyte—A compound or mixture of compounds (e.g., PCBs) tested for by this method. The analytes are listed in Tables 1 and 2.


Analytical batch—The set of samples analyzed on a given instrument during a 24-hour period that begins and ends with calibration verification (sections 7.8 and 13). See also “Extraction batch.”


Blank (method blank; laboratory blank)—An aliquot of reagent water that is treated exactly as a sample including exposure to all glassware, equipment, solvents, reagents, internal standards, and surrogates that are used with samples. The blank is used to determine if analytes or interferences are present in the laboratory environment, the reagents, or the apparatus.


Calibration factor (CF)—See section 7.5.1.


Calibration standard—A solution prepared from stock solutions and/or a secondary standards and containing the analytes of interest, surrogates, and internal standards. This standard is used to model the response of the GC instrument against analyte concentration.


Calibration verification—The process of confirming that the response of the analytical system remains within specified limits of the calibration.


Calibration verification standard—The standard (section 6.8.4) used to verify calibration (sections 7.8 and 13.6).


Extraction Batch—A set of up to 20 field samples (not including QC samples) started through the extraction process in a given 24-hour shift. Each extraction batch of 20 or fewer samples must be accompanied by a blank (section 8.5), a laboratory control sample (LCS, section 8.4), a matrix spike and duplicate (MS/MSD; section 8.3), resulting in a minimum of five samples (1 field sample, 1 blank, 1 LCS, 1 MS, and 1 MSD) and a maximum of 24 samples (20 field samples, 1 blank, 1 LCS, 1 MS, and 1 MSD) for the batch. If greater than 20 samples are to be extracted in a 24-hour shift, the samples must be separated into extraction batches of 20 or fewer samples.


Field Duplicates—Two samples collected at the same time and place under identical conditions, and treated identically throughout field and laboratory procedures. Results of analyses the field duplicates provide an estimate of the precision associated with sample collection, preservation, and storage, as well as with laboratory procedures.


Field blank—An aliquot of reagent water or other reference matrix that is placed in a sample container in the field, and treated as a sample in all respects, including exposure to sampling site conditions, storage, preservation, and all analytical procedures. The purpose of the field blank is to determine if the field or sample transporting procedures and environments have contaminated the sample. See also “Blank.”


GC—Gas chromatograph or gas chromatography.


Gel-permeation chromatography (GPC)—A form of liquid chromatography in which the analytes are separated based on exclusion from the solid phase by size.


Internal standard—A compound added to an extract or standard solution in a known amount and used as a reference for quantitation of the analytes of interest and surrogates. Also see Internal standard quantitation.


Internal standard quantitation—A means of determining the concentration of an analyte of interest (Tables 1 and 2) by reference to a compound not expected to be found in a sample.


IDC—Initial Demonstration of Capability (section 8.2); four aliquots of a reference matrix spiked with the analytes of interest and analyzed to establish the ability of the laboratory to generate acceptable precision and recovery. An IDC is performed prior to the first time this method is used and any time the method or instrumentation is modified.


Laboratory Control Sample (LCS; laboratory fortified blank; section 8.4)—An aliquot of reagent water spiked with known quantities of the analytes of interest and surrogates. The LCS is analyzed exactly like a sample. Its purpose is to assure that the results produced by the laboratory remain within the limits specified in this method for precision and recovery.


Laboratory Fortified Sample Matrix—See Matrix spike.


Laboratory reagent blank—See blank.


Matrix spike (MS) and matrix spike duplicate (MSD) (laboratory fortified sample matrix and duplicate)—Two aliquots of an environmental sample to which known quantities of the analytes of interest and surrogates are added in the laboratory. The MS/MSD are prepared and analyzed exactly like a field sample. Their purpose is to quantify any additional bias and imprecision caused by the sample matrix. The background concentrations of the analytes in the sample matrix must be determined in a separate aliquot and the measured values in the MS/MSD corrected for background concentrations.


May—This action, activity, or procedural step is neither required nor prohibited.


May not—This action, activity, or procedural step is prohibited.


Method detection limit (MDL)—A detection limit determined by the procedure at 40 CFR part 136, appendix B. The MDLs determined by EPA are listed in Tables 1 and 2. As noted in section 1.6, use the MDLs in Tables 1 and 2 in conjunction with current MDL data from the laboratory actually analyzing samples to assess the sensitivity of this procedure relative to project objectives and regulatory requirements (where applicable).


Minimum level (ML)—The term “minimum level” refers to either the sample concentration equivalent to the lowest calibration point in a method or a multiple of the method detection limit (MDL), whichever is higher. Minimum levels may be obtained in several ways: They may be published in a method; they may be based on the lowest acceptable calibration point used by a laboratory; or they may be calculated by multiplying the MDL in a method, or the MDL determined by a laboratory, by a factor of 3. For the purposes of NPDES compliance monitoring, EPA considers the following terms to be synonymous: “quantitation limit,” “reporting limit,” and “minimum level.”


MS—Mass spectrometer or mass spectrometry.


Must—This action, activity, or procedural step is required.


Preparation blank—See blank.


Reagent water—Water demonstrated to be free from the analytes of interest and potentially interfering substances at the MDLs for the analytes in this method.


Regulatory compliance limit—A limit on the concentration or amount of a pollutant or contaminant specified in a nationwide standard, in a permit, or otherwise established by a regulatory/control authority.


Relative standard deviation (RSD)—The standard deviation times 100 divided by the mean. Also termed “coefficient of variation.”


RF—Response factor. See section 7.6.2.


RPD—Relative percent difference.


RSD—See relative standard deviation.


Safety Data Sheet (SDS)—Written information on a chemical’s toxicity, health hazards, physical properties, fire, and reactivity, including storage, spill, and handling precautions that meet the requirements of OSHA, 29 CFR 1910.1200(g) and appendix D to § 1910.1200. United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS), third revised edition, United Nations, 2009.


Should—This action, activity, or procedural step is suggested but not required.


SPE—Solid-phase extraction; a sample extraction or extract cleanup technique in which an analyte is selectively removed from a sample or extract by passage over or through a material capable of reversibly adsorbing the analyte.


Stock solution—A solution containing an analyte that is prepared using a reference material traceable to EPA, the National Institute of Science and Technology (NIST), or a source that will attest to the purity and authenticity of the reference material.


Surrogate—A compound unlikely to be found in a sample, which is spiked into the sample in a known amount before extraction, and which is quantified with the same procedures used to quantify other sample components. The purpose of the surrogate is to monitor method performance with each sample.


Method 609—Nitroaromatics and Isophorone

1. Scope and Application

1.1 This method covers the determination of certain nitroaromatics and isophorone. The following parameters may be determined by this method:


Parameter
STORET No.
CAS No.
2,4-Dinitrotoluene34611121-14-2
2,6-Dinitrotoluene34626606-20-2
Isophorone3440878-59-1
Nitrobenzene3444798-95-3

1.2 This is a gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 606, 608, 611, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.


1.5 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.6 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. Isophorone and nitrobenzene are measured by flame ionization detector gas chromatography (FIDGC). The dinitrotoluenes are measured by electron capture detector gas chromatography (ECDGC).
2


2.2 The method provides a Florisil column cleanup procedure to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baseliles in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
3 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedure in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4-6 for the information of the analyst.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnel—2-L, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Chromatographic column—100 mm long × 10 mm ID, with Teflon stopcock.


5.2.4 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.5 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.6 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.7 Snyder column, Kuderna-Danish—Two-ball micro (Kontes K-569001-0219 or equivalent).


5.2.8 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.6 Gas chromatograph—An analytical system complete with gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.6.1 Column 1—1.2 m long × 2 or 4 mm ID glass, packed with 1.95% QF-1/1.5% OV-17 on Gas-Chrom Q (80/100 mesh) or equivalent. This column was used to develop the method performance statements given in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.


5.6.2 Column 2—3.0 m long × 2 or 4 mm ID glass, packed with 3% OV-101 on Gas-Chrom Q (80/100 mesh) or equivalent.


5.6.3 Detectors—Flame ionization and electron capture detectors. The flame ionization detector (FID) is used when determining isophorone and nitrobenzene. The electron capture detector (ECD) is used when determining the dinitrotoluenes. Both detectors have proven effective in the analysis of wastewaters and were used in develop the method performance statements in Section 14. Guidelines for the use to alternate detectors are provided in Section 12.1.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.3 Sulfuric acid (1 + 1)—Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.


6.4 Acetone, hexane, methanol, methylene chloride—Pesticide quality or equivalent.


6.5 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400 °C for 4 h in a shallow tray.


6.6 Florisil—PR grade (60/100 mesh). Purchase activated at 1250 °F and store in dark in glass containers with ground glass stoppers or foil-lined screw caps. Before use, activate each batch at least 16 h at 200 °C in a foil-covered glass container and allow to cool.


6.7 Stock standard solutions (1.00 µg/µL)—Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.


6.7.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in hexane and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.7.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.7.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.8 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with hexane. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flash. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with hexane. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.


Equation 1.




where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.


7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound.


7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1,5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest in acetone at a concentration of 20 µg/mL for each dinitrotoluene and 100 µg/mL for isophorone and nitrobenzene. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in Table 2 by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at the test concentration in Section 8.2.2 or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determile background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or the test concentration in Section 8.2.2.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100 (A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7 If spiking was performed at a concentration lower than the test concentration in Section 8.2.2, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
8; (3) calculate the range for recovery at the spike concentration as (100 X′/T) ±2.44 (100 S′/T)%.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4. If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
8 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel. Check the pH of the sample with wide-range pH paper and adjust to within the range of 5 to 9 with sodium hydroxide solution or sulfuric acid.


10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.5 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.6 Sections 10.7 and 10.8 describe a procedure for exchanging the methylene chloride solvent to hexane while concentrating the extract volume to 1.0 mL. When it is not necessary to achieve the MDL in Table 2, the solvent exchange may be made by the addition of 50 mL of hexane and concentration to 10 mL as described in Method 606, Sections 10.7 and 10.8.


10.7 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.8 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of methylene chloride. A 5-mL syringe is recommended for this operation. Add 1 to 2 mL of hexane and a clean boiling chip to the concentrator tube and attach a two-ball micro-Snyder column. Prewet the column by adding about 0.5 mL of hexane to the top. Place the micro-K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.9 Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with a minimum amount of hexane. Adjust the extract volume to 1.0 mL. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.


10.10 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use the procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.


11.2 Florisil column cleanup:


11.2.1 Prepare a slurry of 10 g of activated Florisil in methylene chloride/hexane (1 + 9)(V/V) and place the Florisil into a chromatographic column. Tap the column to settle the Florisil and add 1 cm of anhydrous sodium sulfate to the top. Adjust the elution rate to about 2 mL/min.


11.2.2 Just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the sample extract onto the column using an additional 2 mL of hexane to complete the transfer. Just prior to exposure of the sodium sulfate layer to the air, add 30 mL of methylene chloride/hexane (1 + 9)(V/V) and continue the elution of the column. Discard the eluate.


11.2.3 Next, elute the column with 30 mL of acetone/methylene chloride (1 + 9)(V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. Concentrate the collected fraction as in Sections 10.6, 10.7, 10.8, and 10.9 including the solvent exchange to 1 mL of hexane. This fraction should contain the nitroaromatics and isophorone. Analyze by gas chromatography (Section 12).


12. Gas Chromatography

12.1 Isophorone and nitrobenzene are analyzed by injection of a portion of the extract into an FIDGC. The dinitrotoluenes are analyzed by a separate injection into an ECDGC. Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Column 1 are shown in Figures 1 and 2. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


12.2 Calibrate the system daily as described in Section 7.


12.3 If the internal standard calibration procedure is being used, the internal standard must be added to the same extract and mixed thoroughly immediately before injection into the gas chromatograph.


12.4 Inject 2 to 5 µL of the sample extract or standard into the gas chromatograph using the solvent-flush technique.
9 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, the total extract volume, and the resulting peak size in area or peak height units.


12.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


12.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
10 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 7 × MDL to 1000 × MDL.
10


14.3 This method was tested by 18 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 1.0 to 515 µg/L.
11 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Nitroaromatic Compounds and Isophorone in Industrial and Municipal Wastewaters,” EPA 600/ 4-82-024, National Technical Information Service, PB82-208398, Springfield, Virginia 22161, May 1982.


3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


4. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


8. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


9. Burke, J.A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


10. “Determination of Method Detection Limit and Analytical Curve for EPA Method 609—Nitroaromatics and Isophorone,” Special letter report for EPA Contract 68-03-2624, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.


11. “EPA Method Study 19, Method 609 (Nitroaromatics and Isophorone),” EPA 600/4-84-018, National Technical Information Service, PB84-176908, Springfield, Virginia 22161, March 1984.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Col. 1
Col. 2
ECDGC
FIDGC
Nitrobenzene3.314.3113.73.6
2,6-Dinitrotoluene3.524.750.01−
Isophorone4.495.7215.75.7
2,4-Dinitrotoluene5.356.540.02−

Column 1 conditions: Gas-Chrom Q (80/100 mesh) coated with 1.95% QF-1/1.5% OV-17 packed in a 1.2 m long × 2 mm or 4 mm ID glass column. A 2 mm ID column and nitrogen carrier gas at 44 mL/min flow rate were used when determining isophorone and nitrobenzene by FIDGC. The column temperature was held isothermal at 85 °C. A 4 mm ID column and 10% methane/90% argon carrier gas at 44 mL/min flow rate were used when determining the dinitrotoluenes by ECDGC. The column temperature was held isothermal at 145 °C.

Column 2 conditions: Gas-Chrom Q (80/100 mesh) coated with 3% OV-101 packed in a 3.0 m long × 2 mm or 4 mm ID glass column. A 2 mm ID column and nitrogen carrier gas at 44 mL/min flow rate were used when determining isophorone and nitrobenzene by FIDGC. The column temperature was held isothermal at 100 °C. A 4 mm ID column and 10% methane/90% argon carrier gas at 44 mL/min flow rate were used when determining the dinitrotoluenes by ECDGC. The column temperature was held isothermal at 150 °C.


Table 2—QC Acceptance Criteria—Method 609

Parameter
Test Conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (%)
2,4-Dinitrotoluene205.13.6-22.86-125
2,6-Dinitrotoluene204.83.8-23.08-126
Isophorone10032.38.0-100.0D-117
Nitrobenzene10033.325.7-100.06-118

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 609

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
2,4-Dinitro-
toluene0.65C + 0.220.20X
+ 0.08		0.37X
−0.07
2,6-Dinitro-
toluene0.66C + 0.200.19X
+ 0.06		0.36X
−0.00
Isophorone0.49C + 2.930.28X
+ 2.77		0.46X
+ 0.31
Nitrobenzene0.60C + 2.000.25X
+ 2.53		0.37X
−0.78

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.




Method 610—Polynuclear Aromatic Hydrocarbons

1. Scope and Application

1.1 This method covers the determination of certain polynuclear aromatic hydrocarbons (PAH). The following parameters can be determined by this method:


Parameter
STORET No.
CAS No.
Acenaphthene3420583-32-9
Acenaphthylene34200208-96-8
Anthracene34220120-12-7
Benzo(a)anthracene3452656-55-3
Benzo(a)pyrene3424750-32-8
Benzo(b)fluoranthene34230205-99-2
Benzo(ghi)perylene34521191-24-2
Benzo(k)fluoranthene34242207-08-9
Chrysene34320218-01-9
Dibenzo(a,h)anthracene3455653-70-3
Fluoranthene34376206-44-0
Fluorene3438186-73-7
Indeno(1,2,3-cd)pyrene34403193-39-5
Naphthalene3469691-20-3
Phenanthrene3446185-01-8
Pyrene34469129-00-0

1.2 This is a chromatographic method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for many of the parameters listed above, using the extract produced by this method.


1.3 This method provides for both high performance liquid chromatographic (HPLC) and gas chromatographic (GC) approaches for the determination of PAHs. The gas chromatographic procedure does not adequately resolve the following four pairs of compounds: Anthracene and phenanthrene; chrysene and benzo(a)anthracene; benzo(b)fluoranthene and benzo(k)fluoranthene; and dibenzo(a,h) anthracene and indeno (1,2,3-cd)pyrene. Unless the purpose for the analysis can be served by reporting the sum of an unresolved pair, the liquid chromatographic approach must be used for these compounds. The liquid chromatographic method does resolve all 16 of the PAHs listed.


1.4 The method detection limit (MDL, defined in Section 15.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.5 The sample extraction and concentration steps in this method are essentially the same as in Methods 606, 608, 609, 611, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. Selection of the aliquots must be made prior to the solvent exchange steps of this method. The analyst is allowed the latitude, under Sections 12 and 13, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.


1.6 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.7 This method is restricted to use by or under the supervision of analysts experienced in the use of HPLC and GC systems and in the interpretation of liquid and gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and concentrated to a volume of 10 mL or less. The extract is then separated by HPLC or GC. Ultraviolet (UV) and fluorescence detectors are used with HPLC to identify and measure the PAHs. A flame ionization detector is used with GC.
2


2.2 The method provides a silica gel column cleanup procedure to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardward that lead to discrete artifacts and/or elevated baselines in the chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
3 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedure in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


3.3 The extent of interferences that may be encountered using liquid chromatographic techniques has not been fully assessed. Although the HPLC conditions described allow for a unique resolution of the specific PAH compounds covered by this method, other PAH compounds may interfere.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method have not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4-6 for the information of the analyst.


4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: benzo(a)anthracene, benzo(a)pyrene, and dibenzo(a,h)-anthracene. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnel—2-L, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.4 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.5 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.6 Snyder column, Kuderna-Danish—Two-ball micro (Kontes K-569001-0219 or equivalent).


5.2.7 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.2.8 Chromatographic column—250 mm long × 10 mm ID, with coarse frit filter disc at bottom and Teflon stopcock.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.6 High performance liquid chromatograph (HPLC)—An analytical system complete with column supplies, high pressure syringes, detectors, and compatible strip-chart recorder. A data system is recommended for measuring peak areas and retention times.


5.6.1 Gradient pumping system—Constant flow.


5.6.2 Reverse phase column—HC-ODS Sil-X, 5 micron particle diameter, in a 25 cm × 2.6 mm ID stainless steel column (Perkin Elmer No. 089-0716 or equivalent). This column was used to develop the method performance statements in Section 15. Guidelines for the use of alternate column packings are provided in Section 12.2.


5.6.3 Detectors—Fluorescence and/or UV detectors. The fluorescence detector is used for excitation at 280 nm and emission greater than 389 nm cutoff (Corning 3-75 or equivalent). Fluorometers should have dispersive optics for excitation and can utilize either filter or dispersive optics at the emission detector. The UV detector is used at 254 nm and should be coupled to the fluorescence detector. These detectors were used to develop the method performance statements in Section 15. Guidelines for the use of alternate detectors are provided in Section 12.2.


5.7 Gas chromatograph—An analytical system complete with temperature programmable gas chromatograph suitable for on-column or splitless injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.7.1 Column—1.8 m long × 2 mm ID glass, packed with 3% OV-17 on Chromosorb W-AW-DCMS (100/120 mesh) or equivalent. This column was used to develop the retention time data in Table 2. Guidelines for the use of alternate column packings are provided in Section 13.3.


5.7.2 Detector—Flame ionization detector. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), excluding the four pairs of unresolved compounds listed in Section 1.3. Guidelines for the use of alternate detectors are provided in Section 13.3.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Sodium thiosulfate—(ACS) Granular.


6.3 Cyclohexane, methanol, acetone, methylene chloride, pentane—Pesticide quality or equivalent.


6.4 Acetonitrile—HPLC quality, distilled in glass.


6.5 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400 °C for 4 h in a shallow tray.


6.6 Silica gel—100/200 mesh, desiccant, Davison, grade-923 or equivalent. Before use, activate for at least 16 h at 130 °C in a shallow glass tray, loosely covered with foil.


6.7 Stock standard solutions (1.00 µg/µL)—Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.


6.7.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in acetonitrile and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.7.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.7.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.8 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish liquid or gas chromatographic operating conditions equivalent to those given in Table 1 or 2. The chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with acetonitrile. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 5 to 25 µL for HPLC and 2 to 5 µL for GC, analyze each calibration standard according to Section 12 or 13, as appropriate. Tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with acetonitrile. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 5 to 25 µL for HPLC and 2 to 5 µL for GC, analyze each calibration standard according to Section 12 or 13, as appropriate. Tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.




Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, the test must be repeated using a fresh calibration standard. Alternatively, a new calibration curve must be prepared for that compound.


7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, 12.2, and 13.3) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at the following concentrations in acetonitrile: 100 µg/mL of any of the six early-eluting PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, and anthracene); 5 µg/mL of benzo(k)fluoranthene; and 10 µg/mL of any of the other PAHs. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in Table 3 by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 3. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter.



Note:

The large number of parameters in Table 3 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.


8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.


8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.2.6.2 Beginning with Section 8.2.2, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at the test concentration in Section 8.2.2 or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none, (2) the larger of either 5 times higher than the expected background concentration or the test concentration in Section 8.2.2.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100 (A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 3. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7 If spiking was performed at a concentration lower than the test concentration in Section 8.2.2, the analyst must use either the QC acceptance criteria in Table 3, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 4, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 4, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the critiera must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory. If the entire list of parameters in Table 3 must be measured in the sample in Section 8.3, the probability that the analysis of a QC check standard will be required is high. In this case the QC check standard should be routinely analyzed with the spike sample.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 3. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
-2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
8 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction. PAHs are known to be light sensitive; therefore, samples, extracts, and standards should be stored in amber or foil-wrapped bottles in order to minimize photolytic decomposition. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
9 Field test kits are available for this purpose.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.


10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.5 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.7 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of methylene chloride. A 5-mL syringe is recommended for this operation. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial and protected from light. If the sample extract requires no further cleanup, proceed with gas or liquid chromatographic analysis (Section 12 or 13). If the sample requires further cleanup, proceed to Section 11.


10.8 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use the procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the methods as revised to incorporate the cleanup procedure.


11.2 Before the silica gel cleanup technique can be utilized, the extract solvent must be exchanged to cyclohexane. Add 1 to 10 mL of the sample extract (in methylene chloride) and a boiling chip to a clean K-D concentrator tube. Add 4 mL of cyclohexane and attach a two-ball micro-Snyder column. Prewet the column by adding 0.5 mL of methylene chloride to the top. Place the micro-K-D apparatus on a boiling (100 °C) water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of the liquid reaches 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with a minimum amount of cyclohexane. Adjust the extract volume to about 2 mL.


11.3 Silica gel column cleanup for PAHs:


11.3.1 Prepare a slurry of 10 g of activiated silica gel in methylene chloride and place this into a 10-mm ID chromatographic column. Tap the column to settle the silica gel and elute the methylene chloride. Add 1 to 2 cm of anhydrous sodium sulfate to the top of the silica gel.


11.3.2 Preelute the column with 40 mL of pentane. The rate for all elutions should be about 2 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, transfer the 2-mL cyclohexane sample extract onto the column using an additional 2 mL cyclohexane to complete the transfer. Just prior to exposure of the sodium sulfate layer to the air, add 25 mL of pentane and continue the elution of the column. Discard this pentane eluate.


11.3.3 Next, elute the column with 25 mL of methylene chloride/pentane (4 + 6)(V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. Concentrate the collected fraction to less than 10 mL as in Section 10.6. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint with pentane. Proceed with HPLC or GC analysis.


12. High Performance Liquid Chromatography

12.1 To the extract in the concentrator tube, add 4 mL of acetonitrile and a new boiling chip, then attach a two-ball micro-Snyder column. Concentrate the solvent as in Section 10.6, except set the water bath at 95 to 100 °C. When the apparatus is cool, remove the micro-Snyder column and rinse its lower joint into the concentrator tube with about 0.2 mL of acetonitrile. Adjust the extract volume to 1.0 mL.


12.2 Table 1 summarizes the recommended operating conditions for the HPLC. Included in this table are retention times, capacity factors, and MDL that can be achieved under these conditions. The UV detector is recommended for the determination of naphthalene, acenaphthylene, acenapthene, and fluorene and the fluorescence detector is recommended for the remaining PAHs. Examples of the separations achieved by this HPLC column are shown in Figures 1 and 2. Other HPLC columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


12.3 Calibrate the system daily as described in Section 7.


12.4 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the instrument.


12.5 Inject 5 to 25 µL of the sample extract or standard into the HPLC using a high pressure syringe or a constant volume sample injection loop. Record the volume injected to the nearest 0.1 µL, and the resulting peak size in area or peak height units. Re-equilibrate the HPLC column at the initial gradient conditions for at least 10 min between injections.


12.6 Identify the parameters in the sample by comparing the retention time of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


12.7 If the response for a peak exceeds the working range of the system, dilute the extract with acetonitrile and reanalyze.


12.8 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


13. Gas Chromatography

13.1 The packed column GC procedure will not resolve certain isomeric pairs as indicated in Section 1.3 and Table 2. The liquid chromatographic procedure (Section 12) must be used for these parameters.


13.2 To achieve maximum sensitivity with this method, the extract must be concentrated to 1.0 mL. Add a clean boiling chip to the methylene chloride extract in the concentrator tube. Attach a two-ball micro-Snyder column. Prewet the micro-Snyder column by adding about 0.5 mL of methylene chloride to the top. Place the micro-K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with a minimum amount of methylene chloride. Adjust the final volume to 1.0 mL and stopper the concentrator tube.


13.3 Table 2 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times that were obtained under these conditions. An example of the separations achieved by this column is shown in Figure 3. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


13.4 Calibrate the gas chromatographic system daily as described in Section 7.


13.5 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.


13.6 Inject 2 to 5 µL of the sample extract or standard into the gas chromatograph using the solvent-flush technique.
10 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, and the resulting peak size in area or peak height units.


13.7 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


13.8 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


13.9 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


14. Calculations

14.1 Determine the concentration of individual compounds in the sample.


14.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

14.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


15. Method Performance

15.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
11 Similar results were achieved using representative wastewaters. MDL for the GC approach were not determined. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


15.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 8 × MDL to 800 × MDL
11 with the following exception: benzo(ghi)perylene recovery at 80 × and 800 × MDL were low (35% and 45%, respectively).


15.3 This method was tested by 16 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 0.1 to 425 µg/L.
12 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 4.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Polynuclear Aromatic Hydrocarbons in Industrial and Municipal Wastewaters,” EPA 600/4-82-025, National Technical Information Service, PB82-258799, Springfield, Virginia 22161, June 1982.


3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


4. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


8. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


9. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


10. Burke, J.A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


11. Cole, T., Riggin, R., and Glaser, J. “Evaluation of Method Detection Limits and Analytical Curve for EPA Method 610—PNAs,” International Symposium on Polynuclear Aromatic Hydrocarbons, 5th, Battelle’s Columbus Laboratories, Columbus, Ohio (1980).


12. “EPA Method Study 20, Method 610 (PNA’s),” EPA 600/4-84-063, National Technical Information Service, PB84-211614, Springfield, Virginia 22161, June 1984.


Table 1—High Performance Liquid Chromatography Conditions and Method Detection Limits

Parameter
Retention time (min)
Column capacity factor (k′)
Method detection limit (µg/L)
a
Naphthalene16.612.21.8
Acenaphthylene18.513.72.3
Acenaphthene20.515.21.8
Fluorene21.215.80.21
Phenanthrene22.116.60.64
Anthracene23.417.60.66
Fluoranthene24.518.50.21
Pyrene25.419.10.27
Benzo(a)anthracene28.521.60.013
Chrysene29.322.20.15
Benzo(b)fluoranthene31.624.00.018
Benzo(k)fluoranthene32.925.10.017
Benzo(a)pyrene33.925.90.023
Dibenzo(a,h)anthracene35.727.40.030
Benzo(ghi)perylene36.327.80.076
Indeno(1,2,3-cd)pyrene37.428.70.043

HPLC column conditions: Reverse phase HC-ODS Sil-X, 5 micron particle size, in a 25 cm × 2.6 mm ID stainless steel column. Isocratic elution for 5 min. using acetonitrile/water (4 + 6), then linear gradient elution to 100% acetonitrile over 25 min. at 0.5 mL/min flow rate. If columns having other internal diameters are used, the flow rate should be adjusted to maintain a linear velocity of 2 mm/sec.


a The MDL for naphthalene, acenaphthylene, acenaphthene, and fluorene were determined using a UV detector. All others were determined using a fluorescence detector.


Table 2—Gas Chromatographic Conditions and Retention Times

Parameter
Retention time (min)
Naphthalene4.5
Acenaphthylene10.4
Acenaphthene10.8
Fluorene12.6
Phenanthrene15.9
Anthracene15.9
Fluoranthene19.8
Pyrene20.6
Benzo(a)anthracene24.7
Chrysene24.7
Benzo(b)fluoranthene28.0
Benzo(k)fluoranthene28.0
Benzo(a)pyrene29.4
Dibenzo(a,h)anthracene36.2
Indeno(1,2,3-cd)pyrene36.2
Benzo(ghi)perylene38.6

GC Column conditions: Chromosorb W-AW-DCMS (100/120 mesh) coated with 3% OV-17 packed in a 1.8 × 2 mm ID glass column with nitrogen carrier gas at 40 mL/min. flow rate. Column temperature was held at 100 °C for 4 min., then programmed at 8 °C/min. to a final hold at 280 °C.


Table 3—QC Acceptance Criteria—Method 610

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (%)
Acenaphthene10040.3D-105.7D-124
Acenaphthylene10045.122.1-112.1D-139
Anthracene10028.711.2-112.3D-126
Benzo(a)anthracene104.03.1-11.612-135
Benzo(a)pyrene104.00.2-11.0D-128
Benzo(b)fluor-anthene103.11.8-13.86-150
Benzo(ghi)perylene102.3D-10.7D-116
Benzo(k)fluo-ranthene52.5D-7.0D-159
Chrysene104.2D-17.5D-199
Dibenzo(a,h)an-thracene102.00.3-10.0D-110
Fluoranthene103.02.7-11.114-123
Fluorene10043.0D-119D-142
Indeno(1,2,3-cd)pyrene103.01.2-10.0D-116
Naphthalene10040.721.5-100.0D-122
Phenanthrene10037.78.4-133.7D-155
Pyrene103.41.4-12.1D-140

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 4. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 4.


Table 4—Method Accuracy and Precision as Functions of Concentration—Method 610

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′

(µg/L)
Acenaphthene0.52C + 0.540.39X
+ 0.76		0.53X
+ 1.32
Acenaphthylene0.69C − 1.890.36X
+ 0.29		0.42X
+ 0.52
Anthracene0.63C − 1.260.23X
+ 1.16		0.41X
+ 0.45
Benzo(a)anthracene0.73C + 0.050.28X
+ 0.04		0.34X
+ 0.02
Benzo(a)pyrene0.56C + 0.010.38X
− 0.01		0.53X
− 0.01
Benzo(b)fluoranthene0.78C + 0.010.21X
+ 0.01		0.38X
− 0.00
Benzo(ghi)perylene0.44C + 0.300.25X
+ 0.04		0.58X
+ 0.10
Benzo(k)fluoranthene0.59C + 0.000.44X
− 0.00		0.69X
+ 0.01
Chrysene0.77C − 0.180.32X
− 0.18		0.66X
− 0.22
Dibenzo(a,h)anthracene0.41C + 0.110.24X
+ 0.02		0.45X
+ 0.03
Fluoranthene0.68C + 0.070.22X
+ 0.06		0.32X
+ 0.03
Fluorene0.56C − 0.520.44X
− 1.12		0.63X
− 0.65
Indeno(1,2,3-cd)pyrene0.54C + 0.060.29X
+ 0.02		0.42X
+ 0.01
Naphthalene0.57C − 0.700.39X
− 0.18		0.41X
+ 0.74
Phenanthrene0.72C − 0.950.29X
+ 0.05		0.47X
− 0.25
Pyrene0.69C − 0.120.25X
+ 0.14		0.42X
− 0.00

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.





Method 611—Haloethers

1. Scope and Application

1.1 This method covers the determination of certain haloethers. The following parameters can be determined by this method:


Parameter
STORET No.
CAS No.
Bis(2-chloroethyl) ether34273111-44-4
Bis(2-chloroethoxy) methane34278111-91-1
2, 2′-oxybis (1-chloropropane)34283108-60-1
4-Bromophenyl phenyl ether34636101-55-3
4-Chlorophenyl phenyl ether346417005-72-3

1.2 This is a gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 606, 608, 609, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.


1.5 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.6 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the parameters are then measured with a halide specific detector.
2


2.2 The method provides a Florisil column cleanup procedure to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
3 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed be detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such a PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedure in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


3.3 Dichlorobenzenes are known to coelute with haloethers under some gas chromatographic conditions. If these materials are present together in a sample, it may be necessary to analyze the extract with two different column packings to completely resolve all of the compounds.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4-6 for the information of the analyst.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnel—2-L, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Chromatographic column—400 mm long × 19 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0224 or equivalent).


5.2.4 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.5 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.6 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.7 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.6 Gas chromatograph—An analytical system complete with temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.6.1 Column 1—1.8 m long × 2 mm ID glass, packed with 3% SP-1000 on Supelcoport (100/120 mesh) or equivalent. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.


5.6.2 Column 2—1.8 m long × 2 mm ID glass, packed with 2,6-diphenylene oxide polymer (60/80 mesh), Tenax, or equivalent.


5.6.3 Detector—Halide specific detector: electrolytic conductivity or microcoulometric. These detectors have proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1). The Hall conductivity detector was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.1. Although less selective, an electron capture detector is an acceptable alternative.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Sodium thiosulfate—(ACS) Granular.


6.3 Acetone, hexane, methanol, methylene chloride, petroleum ether (boiling range 30-60 °C)—Pesticide quality or equivalent.


6.4 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400 °C for 4 h in a shallow tray.


6.5 Florisil—PR Grade (60/100 mesh). Purchase activated at 1250 °F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. Before use, activate each batch at least 16 h at 130 °C in a foil-covered glass container and allow to cool.


6.6 Ethyl ether—Nanograde, redistilled in glass if necessary.


6.6.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated by EM Laboratories Quant test strips. (Available from Scientific Products Co., Cat. No. P1126-8, and other suppliers.)


6.6.2 Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each liter of ether.


6.7 Stock standard solutions (1.00 µg/µL)—Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.


6.7.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in acetone and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.7.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.7.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.8 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with hexane. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with hexane. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.




Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound.


7.5 The cleanup procedure in Section 11 utilizes Florisil column chromatography. Florisil from different batches or sources may vary in adsorptive capacity. To standardize the amount of Florisil which is used, the use of lauric acid value
7 is suggested. The referenced procedure determines the adsorption from hexane solution of lauric acid (mg) per g of Florisil. The amount of Florisil to be used for each column is calculated by dividing 110 by this ratio and multiplying by 20 g.


7.6 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 100 µg/mL in acetone. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at a concentration of 100 µg/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1. The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 100 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or 100 µg/L.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
8 If spiking was performed at a concentration lower than 100 µg/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
8


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 m/L of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
-2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
9 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
10 Field test kits are available for this purpose.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.


10.2 Add 60 mL methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.5 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.



Note:

Some of the haloethers are very volatile and significant losses will occur in concentration steps if care is not exercised. It is important to maintain a constant gentle evaporation rate and not to allow the liquid volume to fall below 1 to 2 mL before removing the K-D apparatus from the hot water bath.


10.7 Momentarily remove the Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder column. Raise the temperature of the water bath to 85 to 90 °C. Concentrate the extract as in Section 10.6, except use hexane to prewet the column. The elapsed time of concentration should be 5 to 10 min.


10.8 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for this operation. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.


10.9 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use the procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.


11.2 Florisil column cleanup for haloethers:


11.2.1 Adjust the sample extract volume to 10 mL.


11.2.2 Place a weight of Florisil (nominally 20 g) predetermined by calibration (Section 7.5), into a chromatographic column. Tap the column to settle the Florisil and add 1 to 2 cm of anhydrous sodium sulfate to the top.


11.2.3 Preelute the column with 50 to 60 mL of petroleum ether. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the sample extract onto the column by decantation and subsequent petroleum ether washings. Discard the eluate. Just prior to exposure of the sodium sulfate layer to the air, begin eluting the column with 300 mL of ethyl ether/petroleum ether (6 + 94) (V/V). Adjust the elution rate to approximately 5 mL/min and collect the eluate in a 500-mL K-D flask equipped with a 10-mL concentrator tube. This fraction should contain all of the haloethers.


11.2.4 Concentrate the fraction as in Section 10.6, except use hexane to prewet the column. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with hexane. Adjust the volume of the cleaned up extract to 10 mL with hexane and analyze by gas chromatography (Section 12).


12. Gas Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Columns 1 and 2 are shown in Figures 1 and 2, respectively. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


12.2 Calibrate the system daily as described in Section 7.


12.3 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatrograph.


12.4 Inject 2 to 5 µL of the sample extract or standard into the gas chromatograph using the solvent-flush technique.
11 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, the total extract volume, and the resulting peak size in area or peak height units.


12.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weight heavily in the interpretation of chromatograms.


12.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
12 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 4 × MDL to 1000 × MDL.
12


14.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 1.0 to 626 µ/L.
12 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Haloethers in Industrial and Municipal Wastewaters,” EPA 600/4-81-062, National Technical Information Service, PB81-232290, Springfield, Virginia 22161, July 1981.


3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constitutents,” American Society for Testing and Materials, Philadelphia.


4. “Carcinogens—Working Carcinogens, ” Department of Health, Education, and Welfare, Public Health Services, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Mills., P.A. “Variation of Florisil Activity: Simple Method for Measuring Absorbent Capacity and Its Use in Standardizing Florisil Columns,” Journal of the Association of Official Analytical Chemists, 51, 29 (1968).


8. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


9. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


10. “Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


11. Burke, J.A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


12. “EPA Method Study 21, Method 611, Haloethers,” EPA 600/4-84-052, National Technical Information Service, PB84-205939, Springfield, Virginia 22161, June 1984.


Table 1—Chromatographic Conditions and Methods Detection Limits

Parameters
Retention time (min)
Method detection limit (µ/L)
Column 1
Column 2
Bis(2-chloroisopropyl) ether8.49.70.8
Bis(2-chloroethyl) ether9.39.10.3
Bis(2-chloroethoxy) methane13.110.00.5
4-Chlorophenyl ether19.415.03.9
4-Bromophenyl phenyl ether21.216.22.3

Column 1 conditions: Supelcoport (100/120 mesh) coated with 3% SP-1000 packed in a 1.8 m long × 2 mm ID glass column with helium carrier gas at 40 mL/min. flow rate. Column temperature held at 60 °C for 2 min. after injection then programmed at 8 °C/min. to 230 °C and held for 4 min. Under these conditions the retention time for Aldrin is 22.6 min.

Column 2 conditions: Tenax-GC (60/80 mesh) packed in a 1.8 m long × 2mm ID glass column with helium carrier gas at 40 mL/min. flow rate. Column temperature held at 150 °C for 4 min. after injection then programmed at 16 °C/min. to 310 °C. Under these conditions the retention time for Aldrin is 18.4 min.


Table 2—QC Acceptance Criteria—Method 611

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps percent
Bis (2-chloroethyl)ether10026.326.3-136.811-152
Bis (2-chloroethoxy)methane10025.727.3-115.012-128
Bis (2-chloroisopropyl)ether10032.726.4-147.09-165
4-Bromophenyl phenyl ether10039.37.6-167.5D-189
4-Chlorophenyl phenyl ether10030.715.4-152.5D-170

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 611

Parameter
Accuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
Bis(2-chloroethyl) ether0.81C + 0.540.19X
+ 0.28		0.35X
+ 0,36
Bis(2-chloroethoxy) methane0.71C + 0.130.20X
+ 0.15		0.33X
+ 0.11
Bis(2-chloroisopropyl) ether0.85C + 1.670.20X
+ 1.05		0.36X
+ 0.79
4-Bromophenyl phenyl ether0.85C + 2.550.25X
+ 0.21		0.47X
+ 0.37
4-Chlorophenyl phenyl ether0.82C + 1.970.18X
+ 2.13		0.41X
+ 0.55

X′ = Expected recovery for one or more measuremelts of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.




Method 612—Chlorinated Hydrocarbons

1. Scope and Application

1.1 This method covers the determination of certain chlorinated hydrocarbons. The following parameters can be determined by this method:


Parameter
STORET No.
CAS No.
2-Chloronaphthalene3458191-58-7
1,2-Dichlorobenzene3453695-50-1
1,3-Dichlorobenzene34566541-73-1
1,4-Dichlorobenzene34571106-46-7
Hexachlorobenzene39700118-74-1
Hexachlorobutadiene3439187-68-3
Hexachlorocyclopentadiene3438677-47-4
Hexachloroethane3439667-72-1
1,2,4-Trichlorobenzene34551120-82-1

1.2 This is a gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 606, 608, 609, and 611. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.


1.5 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.6 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the parameters are then measured with an electron capture detector.
2


2.2 The method provides a Florisil column cleanup procedure to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
3 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedure in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
4-6 for the information of the analyst.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1cL or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnel—2-L, with Teflon stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long × 19 mm ID, with coarse frit filter disc.


5.2.3 Chromatographic column—300 long × 10 mm ID, with Teflon stopcock and coarse frit filter disc at bottom.


5.2.4 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.5 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.6 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.7 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balance—Analytical, capable of accurately weighing 0.0001 g.


5.6 Gas chromatograph—An analytical system complete with gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.


5.6.1 Column 1—1.8 m long × 2 mm ID glass, packed with 1% SP-1000 on Supelcoport (100/120 mesh) or equivalent. Guidelines for the use of alternate column packings are provide in Section 12.1.


5.6.2 Column 2—1.8 m long × 2 mm ID glass, packed with 1.5% OV-1/2.4% OV-225 on Supelcoport (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 14.


5.6.3 Detector—Electron capture detector. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.1.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.


6.2 Acetone, hexane, isooctane, methanol, methylene chloride, petroleum ether (boiling range 30 to 60 °C)—Pesticide quality or equivalent.


6.3 Sodium sulfate—(ACS) Granular, anhydrous. Purify heating at 400 °C for 4 h in a shallow tray.


6.4 Florisil—PR grade (60/100 mesh). Purchase activated at 1250 °F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. Before use, activate each batch at least 16 h at 130 °C in a foil-covered glass container and allow to cool.


6.5 Stock standard solution (1.00 µg/µL)—Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.


6.5.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in isooctane and dilute to volume in a 120-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.5.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 °C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.


6.5.3 Stock standard solutions must be replaced after six months, or sooner if comparision with check standards indicates a problem.


6.6 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).


7.2 External standard calibration procedure:


7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with isooctane. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.2.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (

7.3 Internal standard calibration procedure—To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.


7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with isooctane. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.


7.3.2 Using injections of 2 to 5 µL, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.




Equation 1

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the parameter to be measured (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±15%, a new calibration curve must be prepared for that compound.


7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When the results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at the following concentrations in acetone: Hexachloro-substituted parameters, 10 µg/mL; any other chlorinated hydrocarbon, 100 µg/mL. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in Table 2 by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for each parameter using the four results.


8.2.5 For each parameter compare s and X
with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, the system performance is unacceptable for that parameter.



Note:

The large number of parameters in Table 2 presents a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.


8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.


8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.


8.2.6.2 Beginning with Section 8.2.2, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spike sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at the test concentration in Section 8.2.2 or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none by (2) the larger of either 5 times higher than the expected background concentration or the test concentration in Section 8.2.2.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. In necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100 (A−B)%/T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
7 If spiking was performed at a concentration lower than the test concentration in Section 8.2.2, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X
; (3) calculate the range for recovery at the spike concentration as (100 X′/T) ±2.44 (100 S′/T)%.
7


8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.


8.4. If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Sections 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P−2sp to P + 2sp. If P = 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevent performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
8 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C from the time of collection until extraction.


9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.


10.2 Add 60 mL of methylele chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.5 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.


10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 to 2 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.



Note:

The dichloribenzenes have a sufficiently high volatility that significant losses may occur in concentration steps if care is not exercised. It is important to maintain a constant gentle evaporation rate and not to allow the liquid volume to fall below 1 to 2 mL before removing the K-D apparatus from the hot water bath.


10.7 Momentarily remove the Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder column. Raise the tempeature of the water bath to 85 to 90 °C. Concentrate the extract as in Section 10.6, except use hexane to prewet the column. The elapsed time of concentration should be 5 to 10 min.


10.8 Romove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for this operation. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.


10.9 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use the procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.


11.2 Florisil column cleanup for chlorinated hydrocarbons:


11.2.1 Adjust the sample extract to 10 mL with hexane.


11.2.2 Place 12 g of Florisil into a chromatographic column. Tap the column to settle the Florisil and add 1 to 2 cm of anhydrous sodium sulfate to the top.


11.2.3 Preelute the column with 100 mL of petroleum ether. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the sample extract onto the column by decantation and subsequent petroleum ether washings. Discard the eluate. Just prior to exposure of the sodium sulfate layer to the air, begin eluting the column with 200 mL of petroleum ether and collect the eluate in a 500-mL K-D flask equipped with a 10-mL concentrator tube. This fraction should contain all of the chlorinated hydrocarbons.


11.2.4 Concentrate the fraction as in Section 10.6, except use hexane to prewet the column. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with hexane. Analyze by gas chromatography (Section 12).


12. Gas Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Columl 2 are shown in Figures 1 and 2. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.


12.2 Calibrate the system daily as described in Section 7.


12.3 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed throughly immediately before injection into the gas chromatograph.


12.4 Inject 2 to 5 µL of the sample extract or standard into the gas chromatograph using the solvent-flush techlique.
9 Smaller (1.0 µL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 µL, the total extract volume, and the resulting peak size in area or peak height units.


12.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.


12.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.


12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.


13. Calculations

13.1 Determine the concentration of individual compounds in the sample.


13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2.




Equation 2

where:

A = Amount of material injected (ng).

Vi = Volume of extract injected (µL).

Vt = Volume of total extract (µL).

Vs = Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3.




Equation 3

where:

As = Response for the parameter to be measured.

Ais = Response for the internal standard.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentrations listed in Table 1 were obtained using reagent water.
10 Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 4 × MDL to 1000 × MDL.
10


14.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 1.0 to 356 µg/L.
11 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. “Determination of Chlorinated Hydrocarbons In Industrial and Municipal Wastewaters, “EPA 6090/4-84-ABC, National Technical Information Service, PBXYZ, Springfield, Virginia, 22161 November 1984.


3. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


4. “Carcinogens—Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


5. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


7. Provost, L.P., and Elder, R.S. “Interpretation of Percent Recovery Data,”American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


8. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


9. Burke, J.A. “Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,” Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).


10. “Development of Detection Limits, EPA Method 612, Chlorinated Hydrocarbons,” Special letter report for EPA Contract 68-03-2625, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268.


11. “EPA Method Study Method 612—Chlorinated Hydrocarbons,” EPA 600/4-84-039, National Technical Information Service, PB84-187772, Springfield, Virginia 22161, May 1984.


12. “Method Performance for Hexachlorocyclopentadiene by Method 612,” Memorandum from R. Slater, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, December 7, 1983.


Table 1—Chromatographic Conditions and Method Detection Limits

Parameter
Retention time (min)
Method detection limit (µg/L)
Column 1
Column 2
1,3-Dichlorobenzene4.56.81.19
Hexachloroethane4.98.30.03
1,4-Dichlorobenzene5.27.61.34
1,2-Dichlorobenzene6.69.31.14
Hexachlorobutadiene7.720.00.34
1,2,4-Trichlorobenzene15.522.30.05
Hexachlorocyclopentadienend
c 16.5		0.40
2-Chloronaphthalene
a 2.7
b 3.6		0.94
Hexachlorobenzene
a 5.6
b 10.1		0.05

Column 1 conditions: Supelcoport (100/120 mesh) coated with 1% SP-1000 packed in a 1.8 m × 2 mm ID glass column with 5% methane/95% argon carrier gas at 25 mL/min. flow rate. Column temperature held isothermal at 65 °C, except where otherwise indicated.

Column 2 conditions: Supelcoport (80/100 mesh) coated with 1.5% OV-1/2.4% OV-225 packed in a 1.8 m × 2 mm ID glass column with 5% methane/95% argon carrier gas at 25 mL/min. flow rate. Column temperature held isothermal at 75 °C, except where otherwise indicated.

nd = Not determined.


a 150 °C column temperature.


b 165 °C column temperature.


c 100 °C column temperature.


Table 2—QC Acceptance Criteria—Method 612

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X
(µg/L)
Range for P, Ps (percent)
2-Chloronaphthalene10037.329.5-126.99-148
1,2-Dichlorobenzene10028.323.5-145.19-160
1,3-Dichlorobenzene10026.47.2-138.6D-150
1,4-Dichlorobenzene10020.822.7-126.913-137
Hexachlorobenzene102.42.6-14.815-159
Hexachlorobutadiene102.2D-12.7D-139
Hexachlorocyclopentadiene102.5D-10.4D-111
Hexachloroethane103.32.4-12.38-139
1,2,4-Trichlorobenzene10031.620.2-133.75-149

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 612

Parameter
Acccuracy, as recovery, X′ (µg/L)
Single analyst precision, sr′ (µg/L)
Overall precision, S′ (µg/L)
2-Chloronaphthalene0.75C + 3.210.28X
−1.17		0.38X
−1.39
1,2-Dichlorobenzene0.85C−0.700.22X
−2.95		0.41X
−3.92
1,3-Dichlorobenzene0.72C + 0.870.21X
−1.03		0.49X
−3.98
1,4-Dichlorobenzene0.72C + 2.800.16X
−0.48		0.35X
−0.57
Hexachlorobenzene0.87C−0.020.14X
+ 0.07		0.36X
−0.19
Hexachlorobutadiene0.61C + 0.030.18X
+ 0.08		0.53X
−0.12
Hexachlorocyclopentadiene
a		0.47C0.24X
0.50X

Hexachloroethane0.74C−0.020.23X
+ 0.07		0.36X
−0.00
1,2,4-Trichlorobenzene0.76C + 0.980.23X
−0.44		0.40X
−1.37

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.


a Estimates based upon the performance in a single laboratory.
12




Method 613—2,3,7,8-Tetrachlorodibenzo-p-Dioxin

1. Scope and Application

1.1 This method covers the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). The following parameter may be determined by this method:


Parameter
STORET No.
GAS No.
2,3,7,8-TCDD346751746-01-6

1.2 This is a gas chromatographic/mass spectrometer (GC/MS) method applicable to the determination of 2,3,7,8-TCDD in municipal and industrial discharges as provided under 40 CFR 136.1. Method 625 may be used to screen samples for 2,3,7,8-TCDD. When the screening test is positive, the final qualitative confirmation and quantification must be made using Method 613.


1.3 The method detection limit (MDL, defined in Section 14.1)
1 for 2,3,7,8-TCDD is listed in Table 1. The MDL for a specific wastewater may be different from that listed, depending upon the nature of interferences in the sample matrix.


1.4 Because of the extreme toxicity of this compound, the analyst must prevent exposure to himself, of to others, by materials knows or believed to contain 2,3,7,8-TCDD. Section 4 of this method contains guidelines and protocols that serve as minimum safe-handling standards in a limited-access laboratory.


1.5 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.6 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph/mass spectrometer and in the interpretation of mass spectra. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.


2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is spiked with an internal standard of labeled 2,3,7,8-TCDD and extracted with methylene chloride using a separatory funnel. The methylene chloride extract is exchanged to hexane during concentration to a volume of 1.0 mL or less. The extract is then analyzed by capillary column GC/MS to separate and measure 2,3,7,8-TCDD.
2 3


2.2 The method provides selected column chromatographic cleanup proceudres to aid in the elimination of interferences that may be encountered.


3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated backgrounds at the masses (m/z) monitored. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.


3.1.1 Glassware must be scrupulously cleaned.
4 Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 °C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by the treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.


3.1.2 The use of high purity reagents and solvents helps to mininmize interference problems. Purification of solvents by distillation in all-glass systems may be required.


3.2 Matrix interferences may be caused by contaminants that are coextracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. 2,3,7,8-TCDD is often associated with other interfering chlorinated compounds which are at concentrations several magnitudes higher than that of 2,3,7,8-TCDD. The cleanup producers in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches
1 5-7 to eliminate false positives and achieve the MDL listed in Table 1.


3.3 The primary column, SP-2330 or equivalent, resolves 2,3,7,8-TCDD from the other 21 TCDD insomers. Positive results using any other gas chromatographic column must be confirmed using the primary column.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified
8-10 for the information of the analyst. Benzene and 2,3,7,8-TCDD have been identified as suspected human or mammalian carcinogens.


4.2 Each laboratory must develop a strict safety program for handling 2,3,7,8-TCDD. The following laboratory practices are recommended:


4.2.1 Contamination of the laboratory will be minimized by conducting all manipulations in a hood.


4.2.2 The effluents of sample splitters for the gas chromatograph and roughing pumps on the GC/MS should pass through either a column of activated charcoal or be bubbled through a trap containing oil or high-boiling alcohols.


4.2.3 Liquid waste should be dissolved in methanol or ethanol and irradiated with ultraviolet light with a wavelength greater than 290 nm for several days. (Use F 40 BL lamps or equivalent). Analyze liquid wastes and dispose of the solutions when 2,3,7,8-TCDD can no longer be detected.


4.3 Dow Chemical U.S.A. has issued the following precautimns (revised November 1978) for safe handling of 2,3,7,8-TCDD in the laboratory:


4.3.1 The following statements on safe handling are as complete as possible on the basis of available toxicological information. The precautions for safe handling and use are necessarily general in nature since detailed, specific recommendations can be made only for the particular exposure and circumstances of each individual use. Inquiries about specific operations or uses may be addressed to the Dow Chemical Company. Assistance in evaluating the health hazards of particular plant conditions may be obtained from certain consulting laboratories and from State Departments of Health or of Labor, many of which have an industrial health service. 2,3,7,8-TCDD is extremely toxic to laboratory animals. However, it has been handled for years without injury in analytical and biological laboratories. Techniques used in handling radioactive and infectious materials are applicable to 2,3,7,8,-TCDD.


4.3.1.1 Protective equipment—Throw-away plastic gloves, apron or lab coat, safety glasses, and a lab hood adequate for radioactive work.


4.3.1.2 Training—Workers must be trained in the proper method of removing contaminated gloves and clothing without contacting the exterior surfaces.


4.3.1.3 Personal hygiene—Thorough washing of hands and forearms after each manipulation and before breaks (coffee, lunch, and shift).


4.3.1.4 Confinement—Isolated work area, posted with signs, segregated glassware and tools, plastic-backed absorbent paper on benchtops.


4.3.1.5 Waste—Good technique includes minimizing contaminated waste. Plastic bag liners should be used in waste cans. Janitors must be trained in the safe handling of waste.


4.3.1.6 Disposal of wastes—2,3,7,8-TCDD decomposes above 800 °C. Low-level waste such as absorbent paper, tissues, animal remains, and plastic gloves may be burned in a good incinerator. Gross quantities (milligrams) should be packaged securely and disposed through commercial or governmental channels which are capable of handling high-level radioactive wastes or extremely toxic wastes. Liquids should be allowed to evaporate in a good hood and in a disposable container. Residues may then be handled as above.


4.3.1.7 Decontamination—For personal decontamination, use any mild soap with plenty of scrubbing action. For decontamination of glassware, tools, and surfaces, Chlorothene NU Solvent (Trademark of the Dow Chemical Company) is the least toxic solvent shown to be effective. Satisfactory cleaning may be accomplished by rinsing with Chlorothene, then washing with any detergent and water. Dishwater may be disposed to the sewer. It is prudent to minimize solvent wastes because they may require special disposal through commercial sources which are expensive.


4.3.1.8 Laundry—Clothing known to be contaminated should be disposed with the precautions described under Section 4.3.1.6. Lab coats or other clothing worn in 2,3,7,8-TCDD work areas may be laundered.


Clothing should be collected in plastic bags. Persons who convey the bags and launder the clothing should be advised of the hazard and trained in proper handling. The clothing may be put into a washer without contact if the launderer knows the problem. The washer should be run through a cycle before being used again for other clothing.


4.3.1.9 Wipe tests—A useful method of determining cleanliness of work surfaces and tools is to wipe the surface with a piece of filter paper. Extraction and analysis by gas chromatography can achieve a limit of sensitivity of 0.1 µg per wipe. Less than 1 µg of 2,3,7,8-TCDD per sample indicates acceptable cleanliness; anything higher warrants further cleaning. More than 10 µg on a wipe sample constitutes an acute hazard and requires prompt cleaning before further use of the equipment or work space. A high (>10 µg) 2,3,7,8-TCDD level indicates that unacceptable work practices have been employed in the past.


4.3.1.10 Inhalation—Any procedure that may produce airborne contamination must be done with good ventilation. Gross losses to a ventilation system must not be allowed. Handling of the dilute solutions normally used in analytical and animal work presents no inhalation hazards except in the case of an accident.


4.3.1.11 Accidents—Remove contaminated clothing immediately, taking precautions not to contaminate skin or other articles. Wash exposed skin vigorously and repeatedly until medical attention is obtained.


5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.


5.1.3 Clearly label all samples as “POISON” and ship according to U.S. Department of Transportation regulations.


5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):


5.2.1 Separatory funnels—2-L and 125-mL, with Teflon stopcock.


5.2.2 Concentrator tube, Kuderna-Danish—10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.


5.2.3 Evaporative flask, Kuderna-Danish—500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.


5.2.4 Snyder column, Kuderna-Danish—Three-ball macro (Kontes K-503000-0121 or equivalent).


5.2.5 Snyder column, Kuderna-Danish—Two-ball micro (Kontes K-569001-0219 or equivalent).


5.2.6 Vials—10 to 15-mL, amber glass, with Teflon-lined screw cap.


5.2.7 Chromatographic column—300 mm long × 10 mm ID, with Teflon stopcock and coarse frit filter disc at bottom.


5.2.8 Chromatographic column—400 mm long × 11 mm ID, with Teflon stopcock and coarse frit filter disc at bottom.


5.3 Boiling chips—Approximately 10/40 mesh. Heat to 400 °C for 30 min or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 GC/MS system:


5.5.1 Gas chromatograph—An analytical system complete with a temperature programmable gas chromatograph and all required accessories including syringes, analytical columns, and gases. The injection port must be designed for capillary columns. Either split, splitless, or on-column injection techniques may be employed, as long as the requirements of Section 7.1.1 are achieved.


5.5.2 Column—60 m long × 0.25 mm ID glass or fused silica, coated with SP-2330 (or equivalent) with a film thickness of 0.2 µm. Any equivalent column must resolve 2, 3, 7, 8-TCDD from the other 21 TCDD isomers.
16


5.5.3 Mass spectrometer—Either a low resolution mass spectrometer (LRMS) or a high resolution mass spectrometer (HRMS) may be used. The mass spectrometer must be equipped with a 70 V (nominal) ion source and be capable of aquiring m/z abundance data in real time selected ion monitoring (SIM) for groups of four or more masses.


5.5.4 GC/MS interface—Any GC to MS interface can be used that achieves the requirements of Section 7.1.1. GC to MS interfaces constructed of all glass or glass-lined materials are recommended. Glass surfaces can be deactivated by silanizing with dichlorodimethylsilane. To achieve maximum sensitivity, the exit end of the capillary column should be placed in the ion source. A short piece of fused silica capillary can be used as the interface to overcome problems associated with straightening the exit end of glass capillary columns.


5.5.5 The SIM data acquired during the chromatographic program is defined as the Selected Ion Current Profile (SICP). The SICP can be acquired under computer control or as a real time analog output. If computer control is used, there must be software available to plot the SICP and report peak height or area data for any m/z in the SICP between specified time or scan number limits.


5.6 Balance—Analytical, capable of accurately weighing 0.0001 g.


6. Reagents

6.1 Reagent water—Reagent water is defined as a water in which an interferent is not observed at the MDL of 2, 3, 7, 8-TCDD.


6.2 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL. Wash the solution with methylene chloride and hexane before use.


6.3 Sodium thiosulfate—(ACS) Granular.


6.4 Sulfuric acid—Concentrated (ACS, sp. gr. 1.84).


6.5 Acetone, methylene chloride, hexane, benzene, ortho-xylene, tetradecane—Pesticide quality or equivalent.


6.6 Sodium sulfate—(ACS) Granular, anhydrous. Purify by heating at 400 °C for 4 h in a shallow tray.


6.7 Alumina—Neutral, 80/200 mesh (Fisher Scientific Co., No. A-540 or equivalent). Before use, activate for 24 h at 130 °C in a foil-covered glass container.


6.8 Silica gel—High purity grade, 100/120 mesh (Fisher Scientific Co., No. S-679 or equivalent).


6.9 Stock standard solutions (1.00 µg/µL)—Stock standard solutimns can be prepared from pure standard materials or purchased as certified solutions. Acetone should be used as the solvent for spiking solutions; ortho-xylene is recommended for calibration standards for split injectors; and tetradecane is recommended for splitless or on-colum injectors. Analyze stock internal standards to verify the absence of native 2,3,7,8-TCDD.


6.9.1 Prepare stock standard solutions of 2,3,7,8-TCDD (mol wt 320) and either
37C14 2,3,7,8-TCDD (mol wt 328) or
13C112 2,3,7,8-TCDD (mol wt 332) in an isolated area by accurately weighing about 0.0100 g of pure material. Dissolve the material in pesticide quality solvent and dilute to volume in a 10-mL volumetric flask. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.


6.9.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store in an isolated refrigerator protected from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards or spiking solutions from them.


6.9.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.


6.10 Internal standard spiking solution (25 ng/mL)—Using stock standard solution, prepare a spiking solution in acetone of either
13 Cl12 or
37 Cl4 2,3,7,8-TCDD at a concentration of 25 ng/mL. (See Section 10.2)


6.11 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Establish gas chromatograhic operating conditions equivalent to those given in Table 1 and SIM conditions for the mass spectrometer as described in Section 12.2 The GC/MS system must be calibrated using the internal standard technique.


7.1.1 Using stock standards, prepare calibration standards that will allow measurement of relative response factors of at least three concentration ratios of 2,3,7,8-TCDD to internal standard. Each calibration standard must be prepared to contain the internal standard at a concentration of 25 ng/mL. If any interferences are contributed by the internal standard at m/z 320 and 322, its concentration may be reduced in the calibration standards and in the internal standard spiking solution (Section 6.10). One of the calibration standards should contain 2,3,7,8-TCDD at a concentration near, but above, the MDL and the other 2,3,7,8-TCDD concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the GC/MS system.


7.1.2 Using injections of 2 to 5 µL, analyze each calibration standardaccording to Section 12 and tabulate peak height or area response against the concentration of 2,3,7,8-TCDD and internal standard. Calculate response factors (RF) for 2,3,7,8-TCDD using Equation 1.




Equation 1

where:

As = SIM response for 2,3,7,8-TCDD m/z 320.

Ais = SIM response for the internal standard, m/z 332 for
13 C12 2,3,7,8-TCDD m/z 328 for
37 Cl4 2,3,7,8-TCDD.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of 2,3,7,8-TCDD (µg/L).

If the RF value over the working range is a constant (s/Ais, vs. RF.

7.1.3 The working calibration curve or RF must be verified on each working day by the measurement of one or more 2,3,7,8-TCDD calibration standards. If the response for 2,3,7,8-TCDD varies from the predicted response by more than ±15%, the test must be repeated using a fresh calibration standard. Alternatively, a new calibration curve must be prepared.


7.2 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.


8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.5, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2


8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples with native 2,3,7,8-TCDD to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.


8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.


8.2.1 A quality control (QC) check sample concentrate is required containing 2,3,7,8-TCDD at a concentration of 0.100 µg/mL in acetone. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.


8.2.2 Using a pipet, prepare QC check samples at a concentration of 0.100 µg/L (100 ng/L) by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.


8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.


8.2.4 Calculate the average recovery (X
) in µg/L, and the standard deviation of the recovery (s) in µg/L, for 2,3,7,8-TCDD using the four results.


8.2.5 Compare s and (X
) with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X
meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If s exceeds the precision limit or X
falls outside the range for accuracy, the system performance is unacceptable for 2,3,7,8-TCDD. Locate and correct the source of the problem and repeat the test beginning with Section 8.2.2.


8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.


8.3.1 The concentration of the spike in the sample should be determined as follows:


8.3.1.1 If, as in compliance monitoring, the concentration of 2,3,7,8-TCDD in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.2 If the concentration of 2,3,7,8-TCDD in the sample is not being checked against a limit specific to that parameter, the spike should be at 0.100 µg/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.


8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or 0.100 µg/L.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of 2,3,7,8-TCDD. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentration in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of 2,3,7,8-TCDD. Calculate percent recovery (P) as 100(A−B)%T, where T is the known true value of the spike.


8.3.3 Compare the percent recovery (P) for 2,3,7,8-TCDD with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst’s spike to background ratio approaches 5:1.
11 If spiking was performed at a concentration lower than 0.100 µg/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of 2,3,7,8-TCDD: (1) Calculate accuracy (X′) using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S′) using the equation in Table 3, substituting X′ for X; (3) calculate the range for recovery at the spike concentration as (100 X′/T)±2.44(100 S′/T)%.
11


8.3.4 If the recovery of 2,3,7,8-TCDD falls outside the designated range for recovery, a check standard must be analyzed as described in Section 8.4.


8.4 If the recovery of 2,3,7,8-TCDD fails the acceptance criteria for recovery in Section 8.3, a QC check standard must be prepared and analyzed.



Note:

The frequency for the required analysis of a QC check standard will depend upon the complexity of the sample matrix and the performance of the laboratory.


8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water.


8.4.2 Analyze the QC check standard to determine the concentration measured (A) of 2,3,7,8-TCDD. Calculate the percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.


8.4.3 Compare the percent recovery (Ps) with the corresponding QC acceptance criteria found in Table 2. If the recovery of 2,3,7,8-TCDD falls outside the designated range, the laboratory performance is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for 2,3,7,8-TCDD in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.


8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P
) and the spandard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P
−2sp to P
+ 2sp. If P
= 90% and sp = 10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment on a regular basis (e.g. after each five to ten new accuracy measurements).


8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices
12 should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.


9.2 All samples must be iced or refrigerated at 4 °C and protected from light from the time of collection until extraction. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine.
13 Field test kits are available for this purpose.


9.3 Label all samples and containers “POISON” and ship according to applicable U.S. Department of Transportation regulations.


9.4 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction.
2


10. Sample Extraction

Caution: When using this method to analyze for 2,3,7,8-TCDD, all of the following operations must be performed in a limited-access laboratory with the analyst wearing full protective covering for all exposed skin surfaces. See Section 4.2.


10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.


10.2 Add 1.00 mL of internal standard spiking solution to the sample in the separatory funnel. If the final extract will be concentrated to a fixed volume below 1.00 mL (Section 12.3), only that volume of spiking solution should be added to the sample so that the final extract will contain 25 ng/mL of internal standard at the time of analysis.


10.3 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the vmlume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.


10.4 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.5 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.


10.6 Pour the combined extract into the K-D concentrator. Rinse the Erlenmeyer flask with 20 to 30 mL of methylele chloride to complete the quantitative transfer.


10.7 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.


10.8 Momentarily remove the Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder column. Raise the temperature of the water bath to 85 to 90 °C. Concentrate the extract as in Section 10.7, except use hexane to prewet the column. Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for this operation. Set aside the K-D glassware for reuse in Section 10.14.


10.9 Pour the hexane extract from the concentrator tube into a 125-mL separatory funnel. Rinse the concentrator tube four times with 10-mL aliquots of hexane. Combine all rinses in the 125-mL separatory funnel.


10.10 Add 50 mL of sodium hydroxide solution to the funnel and shake for 30 to 60 s. Discard the aqueous phase.


10.11 Perform a second wash of the organic layer with 50 mL of reagent water. Discard the aqueous phase.


10.12 Wash the hexane layer with a least two 50-mL aliquots of concentrated sulfuric acid. Continue washing the hexane layer with 50-mL aliquots of concentrated sulfuric acid until the acid layer remains colorless. Discard all acid fractions.


10.13 Wash the hexane layer with two 50-mL aliquots of reagent water. Discard the aqueous phases.


10.14 Transfer the hexane extract into a 125-mL Erlenmeyer flask containing 1 to 2 g of anhydrous sodium sulfate. Swirl the flask for 30 s and decant the hexane extract into the reassembled K-D apparatus. Complete the quantitative transfer with two 10-mL hexane rinses of the Erlenmeyer flask.


10.15 Replace the one or two clean boiling chips and concentrate the extract to 6 to 10 mL as in Section 10.8.


10.16 Add a clean boiling chip to the concentrator tube and attach a two-ball micro-Snyder column. Prewet the column by adding about 1 mL of hexane to the top. Place the micro-K-D apparatus on the water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of hexane.


Adjust the extract volume to 1.0 mL with hexane. Stopper the concentrator tube and store refrigerated and protected from light if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with GC/MS analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.


10.17 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.


11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use either procedure below or any other appropriate procedure.
1 5-7 However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure. Two cleanup column options are offered to the analyst in this section. The alumina column should be used first to overcome interferences. If background problems are still encountered, the silica gel column may be helpful.


11.2 Alumina column cleanup for 2,3,7,8-TCDD:


11.2.1 Fill a 300 mm long × 10 mm ID chromatographic column with activated alumina to the 150 mm level. Tap the column gently to settle the alumina and add 10 mm of anhydrous sodium sulfate to the top.


11.2.2 Preelute the column with 50 mL of hexane. Adjust the elution rate to 1 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 1.0-mL sample extract onto the column using two 2-mL portions of hexane to complete the transfer.


11.2.3 Just prior to exposure of the sodium sulfate layer to the air, add 50 mL of 3% methylene chloride/95% hexane (V/V) and continue the elution of the column. Discard the eluate.


11.2.4 Next, elute the column with 50 mL of 20% methylene chloride/80% hexane (V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. Concentrate the collected fraction to 1.0 mL as in Section 10.16 and analyze by GC/MS (Section 12).


11.3 Silica gel column cleanup for 2,3,7,8-TCDD:


11.3.1 Fill a 400 mm long × 11 mm ID chromatmgraphic column with silica gel to the 300 mm level. Tap the column gently to settle the silica gel and add 10 mm of anhydrous sodium sulfate to the top.


11.3.2 Preelute the column with 50 mL of 20% benzene/80% hexane (V/V). Adjust the elution rate to 1 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 1.0-mL sample extract onto the column using two 2-mL portions of 20% benzene/80% hexane to complete the transfer.


11.3.3 Just prior to exposure of the sodium sulfate layer to the air, add 40 mL of 20% benzene/80% hexane to the column. Collect the eluate in a clean 500-mL K-D flask equipped with a 10-mL concentrator tube. Concentrate the collected fraction to 1.0 mL as in Section 10.16 and analyze by GC/MS.


12. GC/MS Analysis

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Other capillary columns or chromatographic conditions may be used if the requirements of Sections 5.5.2 and 8.2 are met.


12.2 Analyze standards and samples with the mass spectrometer operating in the selected ion monitoring (SIM) mode using a dwell time to give at least seven points per peak. For LRMS, use masses at m/z 320, 322, and 257 for 2,3,7,8-TCDD and either m/z 328 for
37Cl4 2,3,7,8-TCDD or m/z 332 for
13C12 2,3,7,8-TCDD. For HRMS, use masses at m/z 319.8965 and 321.8936 for 2,3,7,8-TCDD and either m/z 327.8847 for
37Cl4 2,3,7,8-TCDD or m/z 331.9367 for
13C12 2,3,7,8-TCDD.


12.3 If lower detection limits are required, the extract may be carefully evaporated to dryness under a gentle stream of nitrogen with the concentrator tube in a water bath at about 40 °C. Conduct this operation immediately before GC/MS analysis. Redissolve the extract in the desired final volume of ortho-xylene or tetradecane.


12.4 Calibrate the system daily as described in Section 7.


12.5 Inject 2 to 5 µL of the sample extract into the gas chromatograph. The volume of calibration standard injected must be measured, or be the same as all sample injection volumes.


12.6 The presence of 2,3,7,8-TCDD is qualitatively confirmed if all of the following criteria are achieved:


12.6.1 The gas chromatographic column must resolve 2,3,7,8-TCDD from the other 21 TCDD isomers.


12.6.2 The masses for native 2,3,7,8-TCDD (LRMS-m/z 320, 322, and 257 and HRMS-m/z 320 and 322) and labeled 2,3,7,8-TCDD (m/z 328 or 332) must exhibit a simultaneous maximum at a retention time that matches that of native 2,3,7,8-TCDD in the calibration standard, with the performance specifications of the analytical system.


12.6.3 The chlorine isotope ratio at m/z 320 and m/z 322 must agree to within±10% of that in the calibration standard.


12.6.4 The signal of all peaks must be greater than 2.5 times the noise level.


12.7 For quantitation, measure the response of the m/z 320 peak for 2,3,7,8-TCDD and the m/z 332 peak for
13C12 2,3,7,8-TCDD or the m/z 328 peak for
37Cl4 2,3,7,8-TCDD.


12.8 Co-eluting impurities are suspected if all criteria are achieved except those in Section 12.6.3. In this case, another SIM analysis using masses at m/z 257, 259, 320 and either m/a 328 or m/z 322 can be performed. The masses at m/z 257 and m/z 259 are indicative of the loss of one chlorine and one carbonyl group from 2,3,7,8-TCDD. If masses m/z 257 and m/z 259 give a chlorine isotope ratio that agrees to within ±10% of the same cluster in the calibration standards, then the presence of TCDD can be confirmed. Co-eluting DDD, DDE, and PCB residues can be confirmed, but will require another injection using the appropriate SIM masses or full repetitive mass scans. If the response for
37Cl4 2,3,7,8-TCDD at m/z 328 is too large, PCB contamination is suspected and can be confirmed by examining the response at both m/z 326 and m/z 328. The
37Cl4 2,3,7,8-TCDD internal standard gives negligible response at m/z 326. These pesticide residues can be removed using the alumina column cleanup procedure.


12.9 If broad background interference restricts the sensitivity of the GC/MS analysis, the analyst should employ additional cleanup procedures and reanalyze by GC/MS.


12.10 In those circumstances where these procedures do not yield a definitive conclusion, the use of high resolution mass spectrometry is suggested.
5


13. Calculations

13.1 Calculate the concentration of 2,3,7,8-TCDD in the sample using the response factor (RF) determined in Section 7.1.2 and Equation 2.




Equation 2

where:

As = SIM response for 2,3,7,8-TCDD at m/z 320.

Ais = SIM response for the internal standard at m/z 328 or 332.

Is = Amount of internal standard added to each extract (µg).

Vo = Volume of water extracted (L).

13.2 For each sample, calculate the percent recovery of the internal standard by comparing the area of the m/z peak measured in the sample to the area of the same peak in the calibration standard. If the recovery is below 50%, the analyst should review all aspects of his analytical technique.


13.3 Report results in µg/L without correction for recovery data. All QC data obtained should be reported with the sample results.


14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero.
1 The MDL concentration listed in Table 1 was obtained using reagent water.
14 The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.


14.2 This method was tested by 11 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 0.02 to 0.20 µg/L.
15 Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.


References

1. 40 CFR part 136, appendix B.


2. “Determination of TCDD in Industrial and Municipal Wastewaters,” EPA 600/4-82-028, National Technical Information Service, PB82-196882, Springfield, Virginia 22161, April 1982.


3. Buser, H.R., and Rappe, C. “High Resolution Gas Chromatography of the 22 Tetrachlorodibenzo-p-dioxin Isomers,” Analytical Chemistry, 52, 2257 (1980).


4. ASTM Annual Book of Standards, Part 31, D3694-78. “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.


5. Harless, R. L., Oswald, E. O., and Wilkinson, M. K. “Sample Preparation and Gas Chromatography/Mass Spectrometry Determination of 2,3,7,8-Tetrachlorodibenzo-p-dioxin,” Analytical Chemistry, 52, 1239 (1980).


6. Lamparski, L. L., and Nestrick, T. J. “Determination of Tetra-, Hepta-, and Octachlorodibenzo-p-dioxin Isomers in Particulate Samples at Parts per Trillion Levels,” Analytical Chemistry, 52, 2045 (1980).


7. Longhorst, M. L., and Shadoff, L. A. “Determination of Parts-per-Trillion Concentrations of Tetra-, Hexa-, and Octachlorodibenzo-p-dioxins in Human Milk,” Analytical Chemistry, 52, 2037 (1980).


8. “Carcinogens—Working with Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


9. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occuptional Safety and Health Administration, OSHA 2206 (Revised, January 1976).


10. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.


11. Provost, L. P., and Elder, R. S., “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)


12. ASTM Annual Book of Standards, Part 31, D3370-76, “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.


13. “Methods, 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric DPD) for Chlorine, Total Residual,” Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.


14. Wong, A.S. et al. “The Determination of 2,3,7,8-TCDD in Industrial and Municipal Wastewaters, Method 613, Part 1—Development and Detection Limits,” G. Choudhay, L. Keith, and C. Ruppe, ed., Butterworth Inc., (1983).


15. “EPA Method Study 26, Method 613: 2,3,7,8-Tetrachlorodibenzo-p-dioxin,” EPA 600/4-84-037, National Technical Information Service, PB84-188879, Springfield, Virginia 22161, May 1984.


Table 1—Chromatographic Conditions and Method Detection Limit

Parameter
Retention time (min)
Method detection limit (µg/L)
2,3,7,8-TCDD13.10.002

Column conditions: SP-2330 coated on a 60 m long × 0.25 mm ID glass column with hydrogen carrier gas at 40 cm/sec linear velocity, splitless injection using tetradecane. Column temperature held isothermal at 200 °C for 1 min, then programmed at 8 °C/min to 250 °C and held. Use of helium carrier gas will approximately double the retention time.


Table 2—QC Acceptance Criteria—Method 613

Parameter
Test conc. (µg/L)
Limit for s (µg/L)
Range for X (µg/L)
Range for P, Ps (%)
2,3,7,8-TCDD0.1000.02760.0523-0.122645-129

s = Standard deviation of four recovery measurements, in µg/L (Section 8.2.4).

X
= Average recovery for four recovery measurements, in µg/L (Section 8.2.4).

P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits for recovery have been broadened to assure applicability of the limits to concentrations below those used to develop Table 3.


Table 3—Method Accuracy and Precision as Functions of Concentration—Method 613

Parameter
Accuracy, as recovery, X″ (µg/L)
Single analyst, precision, sr″ (µ/L)
Overall precision, S″ (µ/g/L)
2,3,7,8-TCDD0.86C + 0.001450.13X
+ 0.00129		0.19X
+ 0.00028

X′ = Expected recovery for one or more measurements. of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X
, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X
, in µg/L.

C = True value for the concentration, in µg/L.

X
= Average recovery found for measurements of samples containing a concentration of C, in µg/L.


Method 624.1—Purgeables by GC/MS

1. Scope and Application

1.1 This method is for determination of purgeable organic pollutants in industrial discharges and other environmental samples by gas chromatography combined with mass spectrometry (GC/MS), as provided under 40 CFR 136.1. This revision is based on previous protocols (References 1—3), on the revision promulgated October 26, 1984, and on an interlaboratory method validation study (Reference 4). Although this method was validated through an interlaboratory study conducted in the early 1980s, the fundamental chemistry principles used in this method remain sound and continue to apply.


1.2 The analytes that may be qualitatively and quantitatively determined using this method and their CAS Registry numbers are listed in Table 1. The method may be extended to determine the analytes listed in Table 2; however, poor purging efficiency or gas chromatography of some of these analytes may make quantitative determination difficult. For example, an elevated temperature may be required to purge some analytes from water. If an elevated temperature is used, calibration and all quality control (QC) tests must be performed at the elevated temperature. EPA encourages the use of this method to determine additional compounds amenable to purge-and-trap GC/MS.


1.3 The large number of analytes in Tables 1 and 2 of this method makes testing difficult if all analytes are determined simultaneously. Therefore, it is necessary to determine and perform QC tests for “analytes of interest” only. Analytes of interest are those required to be determined by a regulatory/control authority or in a permit, or by a client. If a list of analytes is not specified, the analytes in Table 1 must be determined, at a minimum, and QC testing must be performed for these analytes. The analytes in Table 1 and some of the analytes in Table 2 have been identified as Toxic Pollutants (40 CFR 401.15), expanded to a list of Priority Pollutants (40 CFR part 423, appendix A).


1.4 Method detection limits (MDLs; Reference 5) for the analytes in Table 1 are listed in that table. These MDLs were determined in reagent water (Reference 6). Advances in analytical technology, particularly the use of capillary (open-tubular) columns, allowed laboratories to routinely achieve MDLs for the analytes in this method that are 2-10 times lower than those in the version promulgated in 1984. The MDL for a specific wastewater may differ from those listed, depending on the nature of interferences in the sample matrix.


1.4.1 EPA has promulgated this method at 40 CFR part 136 for use in wastewater compliance monitoring under the National Pollutant Discharge Elimination System (NPDES). The data reporting practices described in section 13.2 are focused on such monitoring needs and may not be relevant to other uses of the method.


1.4.2 This method includes “reporting limits” based on EPA’s “minimum level” (ML) concept (see the glossary in section 20). Table 1 contains MDL values and ML values for many of the analytes. The MDL for an analyte in a specific wastewater may differ from that listed in Table 1, depending upon the nature of interferences in the sample matrix.


1.5 This method is performance-based. It may be modified to improve performance (e.g., to overcome interferences or improve the accuracy of results) provided all performance requirements are met.


1.5.1 Examples of allowed method modifications are described at 40 CFR 136.6. Other examples of allowed modifications specific to this method are described in section 8.1.2.


1.5.2 Any modification beyond those expressly allowed at 40 CFR 136.6 or in section 8.1.2 of this method shall be considered a major modification that is subject to application and approval of an alternate test procedure under 40 CFR 136.4 and 136.5.


1.5.3 For regulatory compliance, any modification must be demonstrated to produce results equivalent or superior to results produced by this method when applied to relevant wastewaters (section 8.3).


1.6 This method is restricted to use by or under the supervision of analysts experienced in the operation of a purge-and-trap system and a gas chromatograph/mass spectrometer and in the interpretation of mass spectra. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure in section 8.2.


1.7 Terms and units of measure used in this method are given in the glossary at the end of the method.


2. Summary of Method

2.1 A gas is bubbled through a measured volume of water in a specially-designed purging chamber. The purgeables are efficiently transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the purgeables are trapped. After purging is completed, the trap is heated and backflushed with the gas to desorb the purgeables onto a gas chromatographic column. The column is temperature programmed to separate the purgeables which are then detected with a mass spectrometer.


2.2 Different sample sizes in the range of 5-25 mL are allowed in order to meet differing sensitivity requirements. Calibration and QC samples must have the same volume as field samples.


3. Interferences

3.1 Impurities in the purge gas, organic compounds outgassing from the plumbing ahead of the trap, and solvent vapors in the laboratory account for the majority of contamination problems. The analytical system must be demonstrated to be free from contamination under the conditions of the analysis by analyzing blanks initially and with each analytical batch (samples analyzed on a given 12-hour shift, to a maximum of 20 samples), as described in Section 8.5. Fluoropolymer tubing, fittings, and thread sealant should be used to avoid contamination.


3.2 Samples can be contaminated by diffusion of volatile organics (particularly fluorocarbons and methylene chloride) through the septum seal into the sample during shipment and storage. Protect samples from sources of volatiles during collection, shipment, and storage. A reagent water field blank carried through sampling and analysis can serve as a check on such contamination.


3.3 Contamination by carry-over can occur whenever high level and low level samples are analyzed sequentially. To reduce the potential for carry-over, the purging device and sample syringe must be rinsed with reagent water between sample analyses. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of a blank to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high purgeable levels, it may be necessary to wash the purging device with a detergent solution, rinse it with distilled water, and then dry it in a 105 °C oven between analyses. The trap and other parts of the system are also subject to contamination; therefore, frequent bakeout and purging of the entire system may be required. Screening samples at high dilution may prevent introduction of contaminants into the system.


4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of safety data sheets (SDSs, OSHA, 29 CFR 1910.1200(g)) should also be made available to all personnel involved in sample handling and chemical analysis. Additional references to laboratory safety are available and have been identified (References 7-9) for the information of the analyst.


4.2. The following analytes covered by this method have been tentatively classified as known or suspected human or mammalian carcinogens: Benzene; carbon tetrachloride; chloroform; 1,4-dichlorobenzene; 1,2-dichloroethane; 1,2-dichloropropane; methylene chloride; tetrachloroethylene; trichloroethylene; and vinyl chloride. Primary standards of these toxic compounds should be prepared in a chemical fume hood, and a NIOSH/MESA approved toxic gas respirator should be worn when handling high concentrations of these compounds.


4.3 This method allows the use of hydrogen as a carrier gas in place of helium (Section 5.3.1.2). The laboratory should take the necessary precautions in dealing with hydrogen, and should limit hydrogen flow at the source to prevent buildup of an explosive mixture of hydrogen in air.


5. Apparatus and Materials


Note:

Brand names, suppliers, and part numbers are cited for illustration purposes only. No endorsement is implied. Equivalent performance may be achieved using equipment and materials other than those specified here. Demonstration of equivalent performance that meets the requirements of this method is the responsibility of the laboratory. Suppliers for equipment and materials in this method may be found through an on-line search.


5.1 Sampling equipment for discrete sampling.


5.1.1 Vial—25- or 40-mL capacity, or larger, with screw cap with a hole in the center (Fisher #13075 or equivalent). Unless pre-cleaned, detergent wash, rinse with tap and reagent water, and dry at 105 ± 5 °C before use.


5.1.2 Septum—Fluoropolymer-faced silicone (Fisher #12722 or equivalent). Unless pre-cleaned, detergent wash, rinse with tap and reagent water, and dry at 105 ± 5 °C for one hour before use.


5.2 Purge-and-trap system—The purge-and-trap system consists of three separate pieces of equipment: A purging device, trap, and desorber. Several complete systems are commercially available with autosamplers. Any system that meets the performance requirements in this method may be used.


5.2.1 The purging device should accept 5- to 25-mL samples with a water column at least 3 cm deep. The purge gas must pass though the water column as finely divided bubbles. The purge gas must be introduced no more than 5 mm from the base of the water column. Purge devices of a different volume may be used so long as the performance requirements in this method are met.


5.2.2 The trap should be at least 25 cm long and have an inside diameter of at least 0.105 in. The trap should be packed to contain the following minimum lengths of adsorbents: 1.0 cm of methyl silicone coated packing (section 6.3.2), 15 cm of 2,6-diphenylene oxide polymer (section 6.3.1), and 8 cm of silica gel (section 6.3.3). A trap with different dimensions and packing materials is acceptable so long as the performance requirements in this method are met.


5.2.3 The desorber should be capable of rapidly heating the trap to the temperature necessary to desorb the analytes of interest, and of maintaining this temperature during desorption. The trap should not be heated higher than the maximum temperature recommended by the manufacturer.


5.2.4 The purge-and-trap system may be assembled as a separate unit or coupled to a gas chromatograph.


5.3 GC/MS system.


5.3.1 Gas chromatograph (GC)—An analytical system complete with a temperature programmable gas chromatograph and all required accessories, including syringes and analytical columns. Autosamplers designed for purge-and-trap analysis of volatiles also may be used.


5.3.1.1 Injection port—Volatiles interface, split, splitless, temperature programmable split/splitless (PTV), large volume, on-column, backflushed, or other.


5.3.1.2 Carrier gas—Data in the tables in this method were obtained using helium carrier gas. If another carrier gas is used, analytical conditions may need to be adjusted for optimum performance, and calibration and all QC tests must be performed with the alternative carrier gas. See Section 4.3 for precautions regarding the use of hydrogen as a carrier gas.


5.3.2 GC column—See the footnote to Table 3. Other columns or column systems may be used provided all requirements in this method are met.


5.3.3 Mass spectrometer—Capable of repetitively scanning from 35-260 Daltons (amu) every 2 seconds or less, utilizing a 70 eV (nominal) electron energy in the electron impact ionization mode, and producing a mass spectrum which meets all criteria in Table 4 when 50 ng or less of 4-bromofluorobenzene (BFB) is injected through the GC inlet. If acrolein, acrylonitrile, chloromethane, and vinyl chloride are to be determined, it may be necessary to scan from below 25 Daltons to measure the peaks in the 26-35 Dalton range for reliable identification.


5.3.4 GC/MS interface—Any GC to MS interface that meets all performance requirements in this method may be used.


5.3.5 Data system—A computer system must be interfaced to the mass spectrometer that allows continuous acquisition and storage of mass spectra throughout the chromatographic program. The computer must have software that allows searching any GC/MS data file for specific m/z’s (masses) and plotting m/z abundances versus time or scan number. This type of plot is defined as an extracted ion current profile (EICP). Software must also be available that allows integrating the abundance at any EICP between specified time or scan number limits.


5.4 Syringes—Graduated, 5-25 mL, glass hypodermic with Luerlok tip, compatible with the purging device.


5.5 Micro syringes—Graduated, 25-1000 µL, with 0.006 in. ID needle.


5.6 Syringe valve—Two-way, with Luer ends.


5.7 Syringe—5 mL, gas-tight with shut-off valve.


5.8 Bottle—15 mL, screw-cap, with Teflon cap liner.


5.9 Balance—Analytical, capable of accurately weighing 0.0001 g.


6. Reagents

6.1 Reagent water—Reagent water is defined as water in which the analytes of interest and interfering compounds are not detected at the MDLs of the analytes of interest. It may be generated by passing deionized water, distilled water, or tap water through a carbon bed, passing the water through a water purifier, or heating the water to between 90 and 100 °C while bubbling contaminant-free gas through it for approximately 1 hour. While still hot, transfer the water to screw-cap bottles and seal with a fluoropolymer-lined cap.


6.2 Sodium thiosulfate—(ACS) Granular.


6.3 Trap materials.


6.3.1 2,6-Diphenylene oxide polymer—Tenax, 60/80 mesh, chromatographic grade, or equivalent.


6.3.2 Methyl silicone packing—3% OV-1 on Chromosorb-W, 60/80 mesh, or equivalent.


6.3.3 Silica gel—35/60 mesh, Davison, Grade-15 or equivalent.


6.3.4 Other trap materials are acceptable if performance requirements in this method are met.


6.4 Methanol—Demonstrated to be free from the target analytes and potentially interfering compounds.


6.5 Stock standard solutions—Stock standard solutions may be prepared from pure materials, or purchased as certified solutions. Traceability must be to the National Institute of Standards and Technology (NIST) or other national or international standard, when available. Stock solution concentrations alternative to those below may be used. Prepare stock standard solutions in methanol using assayed liquids or gases as appropriate. Because some of the compounds in this method are known to be toxic, primary dilutions should be prepared in a hood, and a NIOSH/MESA approved toxic gas respirator should be worn when high concentrations of neat materials are handled. The following procedure may be used to prepare standards from neat materials:


6.5.1 Place about 9.8 mL of methanol in a 10-mL ground-glass-stoppered volumetric flask. Allow the flask to stand, unstoppered, for about 10 minutes or until all alcohol wetted surfaces have dried. Weigh the flask to the nearest 0.1 mg.


6.5.2 Add the assayed reference material.


6.5.2.1 Liquids—Using a 100 µL syringe, immediately add two or more drops of assayed reference material to the flask. Be sure that the drops fall directly into the alcohol without contacting the neck of the flask. Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in µg/µL from the net gain in weight.


6.5.2.2 Gases—To prepare standards for any of compounds that boil below 30 °C, fill a 5-mL valved gas-tight syringe with reference standard vapor to the 5.0 mL mark. Lower the needle to 5 mm above the methanol meniscus. Slowly introduce the vapor above the surface of the liquid (the vapor will rapidly dissolve in the methanol). Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in µg/µL from the net gain in weight.


6.5.3 When compound purity is assayed to be 96% or greater, the weight may be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards may be used at any concentration if they are certified by the manufacturer or by an independent source.


6.5.4 Prepare fresh standards weekly for the gases and 2-chloroethylvinyl ether. Unless stated otherwise in this method, store non-aqueous standards in fluoropolymer-lined screw-cap, or heat-sealed, glass containers, in the dark at −20 to −10 °C. Store aqueous standards; e.g., the aqueous LCS (section 8.4.1) in the dark at ≤6 °C (but do not freeze) with zero headspace; e.g., in VOA vials (section 5.1.1). Standards prepared by the laboratory may be stored for up to one month, except when comparison with QC check standards indicates that a standard has degraded or become more concentrated due to evaporation, or unless the laboratory has data on file to prove stability for a longer period. Commercially prepared standards may be stored until the expiration date provided by the vendor, except when comparison with QC check standards indicates that a standard has degraded or become more concentrated due to evaporation, or unless the laboratory has data from the vendor on file to prove stability for a longer period.



Note:

2-Chloroethylvinyl ether has been shown to be stable for as long as one month if prepared as a separate standard, and the other analytes have been shown to be stable for as long as 2 months if stored at less than −10 °C with minimal headspace in sealed, miniature inert-valved vials.


6.6 Secondary dilution standards—Using stock solutions, prepare secondary dilution standards in methanol that contain the compounds of interest, either singly or mixed. Secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in section 7.3.2 will bracket the working range of the analytical system.


6.7 Surrogate standard spiking solution—Select a minimum of three surrogate compounds from Table 5. The surrogates selected should match the purging characteristics of the analytes of interest as closely as possible. Prepare a stock standard solution for each surrogate in methanol as described in section 6.5, and prepare a solution for spiking the surrogates into all blanks, LCSs, and MS/MSDs. Prepare the spiking solution such that spiking a small volume will result in a constant concentration of the surrogates. For example, add 10 µL of a spiking solution containing the surrogates at a concentration of 15 µg/mL in methanol to a 5-mL aliquot of water to produce a concentration of 30 µg/L for each surrogate. Other surrogate concentrations may be used. Store per section 6.5.4.


6.8 BFB standard—Prepare a solution of BFB in methanol as described in Sections 6.5 and 6.6. The solution should be prepared such that an injection or purging from water will result in introduction of ≤ 50 ng into the GC. BFB may be included in a mixture with the internal standards and/or surrogates.


6.9 Quality control check sample concentrate—See Section 8.2.1.


7. Calibration

7.1 Assemble a purge-and-trap system that meets the specifications in Section 5.2. Prior to first use, condition the trap overnight at 180 °C by backflushing with gas at a flow rate of at least 20 mL/min. Condition the trap after each analysis at a temperature and time sufficient to prevent detectable concentrations of the analytes or contaminants in successive analyses.


7.2 Connect the purge-and-trap system to the gas chromatograph. The gas chromatograph should be operated using temperature and flow rate conditions equivalent to those given in the footnotes to Table 3. Alternative temperature and flow rate conditions may be used provided that performance requirements in this method are met.


7.3 Internal standard calibration.


7.3.1 Internal standards.


7.3.1.1 Select three or more internal standards similar in chromatographic behavior to the compounds of interest. Suggested internal standards are listed in Table 5. Use the base peak m/z as the primary m/z for quantification of the standards. If interferences are found at the base peak, use one of the next two most intense m/z’s for quantitation. Demonstrate that measurements of the internal standards are not affected by method or matrix interferences.


7.3.1.2 To assure accurate analyte identification, particularly when selected ion monitoring (SIM) is used, it may be advantageous to include more internal standards than those suggested in Section 7.3.1.1. An analyte will be located most accurately if its retention time relative to an internal standard is in the range of 0.8 to 1.2.


7.3.1.3 Prepare a stock standard solution for each internal standard in methanol as described in Section 6.5, and prepare a solution for spiking the internal standards into all blanks, LCSs, and MS/MSDs. Prepare the spiking solution such that spiking a small volume will result in a constant concentration of the internal standards. For example, add 10 µL of a spiking solution containing the internal standards at a concentration of 15 µg/mL in methanol to a 5-mL aliquot of water to produce a concentration of 30 µg/L for each internal standard. Other concentrations may be used. The internal standard solution and the surrogate standard spiking solution (Section 6.7) may be combined, if desired. Store per section 6.5.4.


7.3.2 Calibration.


7.3.2.1 Calibration standards.


7.3.2.1.1 Prepare calibration standards at a minimum of five concentration levels for each analyte of interest by adding appropriate volumes of one or more stock standards to a fixed volume (e.g., 40 mL) of reagent water in volumetric glassware. Fewer levels may be necessary for some analytes based on the sensitivity of the MS, but no fewer than 3 levels may be used, and only the highest or lowest point(s) may be dropped from the calibration. One of the calibration standards should be at a concentration at or below the ML or as specified by a regulatory/control authority or in a permit. The ML value may be rounded to a whole number that is more convenient for preparing the standard, but must not exceed the ML values listed in Table 1 for those analytes which list ML values. Alternatively, the laboratory may establish the ML for each analyte based on the concentration of the lowest calibration standard in a series of standards produced in the laboratory or obtained from a commercial vendor, again, provided that the ML value does not exceed the MLs in Table 1, and provided that the resulting calibration meets the acceptance criteria in Section 7.3.4, based on the RSD, RSE, or R
2. The concentrations of the higher standards should correspond to the expected range of concentrations found in real samples, or should define the working range of the GC/MS system for full-scan and/or SIM operation, as appropriate. A minimum of six concentration levels is required for a second order, non-linear (e.g., quadratic; ax
2 + bx + c = 0) calibration. Calibrations higher than second order are not allowed.


7.3.2.1.2 To each calibration standard or standard mixture, add a known constant volume of the internal standard spiking solution (section 7.3.1.3) and surrogate standard spiking solution (section 6.7) or the combined internal standard solution and surrogate spiking solution (section 7.3.1.3). Aqueous standards may be stored up to 24 hours, if held in sealed vials with zero headspace. If not so stored, they must be discarded after one hour.


7.3.2.2 Prior to analysis of the calibration standards, analyze the BFB standard (section 6.8) and adjust the scan rate of the MS to produce a minimum of 5 mass spectra across the BFB GC peak, but do not exceed 2 seconds per scan. Adjust instrument conditions until the BFB criteria in Table 4 are met. Once the scan conditions are established, they must be used for analyses of all standards, blanks, and samples.



Note:

The BFB spectrum may be evaluated by summing the intensities of the m/z’s across the GC peak, subtracting the background at each m/z in a region of the chromatogram within 20 scans of but not including any part of the BFB peak. The BFB spectrum may also be evaluated by fitting a Gaussian to each m/z and using the intensity at the maximum for each Gaussian, or by integrating the area at each m/z and using the integrated areas. Other means may be used for evaluation of the BFB spectrum so long as the spectrum is not distorted to meet the criteria in Table 4.


7.3.2.3 Analyze the mid-point standard and enter or review the retention time, relative retention time, mass spectrum, and quantitation m/z in the data system for each analyte of interest, surrogate, and internal standard. If additional analytes (Table 2) are to be quantified, include these analytes in the standard. The mass spectrum for each analyte must be comprised of a minimum of 2 m/z’s; 3 to 5 m/z’s assure more reliable analyte identification. Suggested quantitation m/z’s are shown in Table 6 as the primary m/z. For analytes in Table 6 that do not have a secondary m/z, acquire a mass spectrum and enter one or more secondary m/z’s for more reliable identification. If an interference occurs at the primary m/z, use one of the secondary m/z’s or an alternative m/z. A single m/z only is required for quantitation.


7.3.2.4 For SIM operation, determine the analytes in each descriptor, the quantitation m/z for each analyte (the quantitation m/z can be the same as for full-scan operation; Section 7.3.2.3), the dwell time on each m/z for each analyte, and the beginning and ending retention time for each descriptor. Analyze the verification standard in scan mode to verify m/z’s and establish retention times for the analytes. There must be a minimum of two m/z’s for each analyte to assure analyte identification. To maintain sensitivity, the number of m/z’s in a descriptor should be limited. For example, for a descriptor with 10 m/z’s and a chromatographic peak width of 5 sec, a dwell time of 100 ms at each m/z would result in a scan time of 1 second and provide 5 scans across the GC peak. The quantitation m/z will usually be the most intense peak in the mass spectrum. The quantitation m/z and dwell time may be optimized for each analyte. The acquisition table used for SIM must take into account the mass defect (usually less than 0.2 Dalton) that can occur at each m/z monitored. Refer to the footnotes to Table 3 for establishing operating conditions and to section 7.3.2.2 for establishing scan conditions.


7.3.2.5 For combined scan and SIM operation, set up the scan segments and descriptors to meet requirements in sections 7.3.2.2-7.3.2.4. Analyze unfamiliar samples in the scan mode to assure that the analytes of interest are determined.


7.3.3 Analyze each calibration standard according to Section 10 and tabulate the area at the quantitation m/z against concentration for each analyte of interest, surrogate, and internal standard. Calculate the response factor (RF) for each compound at each concentration using Equation 1.



Where:

As = Area of the characteristic m/z for the analyte to be measured.

Ais = Area of the characteristic m/z for the internal standard.

Cis = Concentration of the internal standard (µg/L).

Cs = Concentration of the analyte to be measured (µg/L).

7.3.4 Calculate the mean (average) and relative standard deviation (RSD) of the response factors. If the RSD is less than 35%, the RF can be assumed to be invariant and the average RF can be used for calculations. Alternatively, the results can be used to fit a linear or quadratic regression of response ratios, As/Ais, vs. concentration ratios Cs/Cis. If used, the regression must be weighted inversely proportional to concentration (1/C). The coefficient of determination (R
2) of the weighted regression must be greater than 0.920 (this value roughly corresponds to the RSD limit of 35%). Alternatively, the relative standard error (Reference 10) may be used as an acceptance criterion. As with the RSD, the RSE must be less than 35%. If an RSE less than 35% cannot be achieved for a quadratic regression, system performance is unacceptable, and the system must be adjusted and re-calibrated.



Note:

Using capillary columns and current instrumentation, it is quite likely that a laboratory can calibrate the target analytes in this method and achieve a linearity metric (either RSD or RSE) well below 35%. Therefore, laboratories are permitted to use more stringent acceptance criteria for calibration than described here, for example, to harmonize their application of this method with those from other sources.


7.4 Calibration verification—Because the analytical system is calibrated by purge of the analytes from water, calibration verification is performed using the laboratory control sample (LCS). See section 8.4 for requirements for calibration verification using the LCS, and the Glossary for further definition.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and ongoing analysis of spiked samples and blanks to evaluate and document data quality (40 CFR 136.7). The laboratory must maintain records to document the quality of data generated. Results of ongoing performance tests are compared with established QC acceptance criteria to determine if the results of analyses meet performance requirements of this method. When results of spiked samples do not meet the QC acceptance criteria in this method, a quality control check sample (laboratory control sample; LCS) must be analyzed to confirm that the measurements were performed in an in-control mode of operation. A laboratory may develop its own performance criteria (as QC acceptance criteria), provided such criteria are as or more restrictive than the criteria in this method.


8.1.1 The laboratory must make an initial demonstration of capability (DOC) to generate acceptable precision and recovery with this method. This demonstration is detailed in Section 8.2. On a continuing basis, the laboratory must repeat demonstration of capability (DOC) at least annually.


8.1.2 In recognition of advances that are occurring in analytical technology, and to overcome matrix interferences, the laboratory is permitted certain options (section 1.5 and 40 CFR 136.6(b)) to improve separations or lower the costs of measurements. These options may include an alternative purge-and-trap device, and changes in both column and type of mass spectrometer (see 40 CFR 136.6(b)(4)(xvi)). Alternative determinative techniques, such as substitution of spectroscopic or immunoassay techniques, and changes that degrade method performance, are not allowed. If an analytical technique other than GC/MS is used, that technique must have a specificity equal to or greater than the specificity of GC/MS for the analytes of interest. The laboratory is also encouraged to participate in inter-comparison and performance evaluation studies (see section 8.8).


8.1.2.1 Each time a modification is made to this method, the laboratory is required to repeat the procedure in section 8.2. If the detection limit of the method will be affected by the change, the laboratory must demonstrate that the MDLs (40 CFR part 136, appendix B) are lower than one-third the regulatory compliance limit or the MDLs in this method, whichever are greater. If calibration will be affected by the change, the instrument must be recalibrated per section 7. Once the modification is demonstrated to produce results equivalent or superior to results produced by this method, that modification may be used routinely thereafter, so long as the other requirements in this method are met (e.g., matrix spike/matrix spike duplicate recovery and relative percent difference).


8.1.2.1.1 If a modification is to be applied to a specific discharge, the laboratory must prepare and analyze matrix spike/matrix spike duplicate (MS/MSD) samples (Section 8.3) and LCS samples (section 8.4). The laboratory must include internal standards and surrogates (section 8.7) in each of the samples. The MS/MSD and LCS samples must be fortified with the analytes of interest (section 1.3.). If the modification is for nationwide use, MS/MSD samples must be prepared from a minimum of nine different discharges (See section 8.1.2.1.2), and all QC acceptance criteria in this method must be met. This evaluation only needs to be performed once, other than for the routine QC required by this method (for example it could be performed by the vendor of the alternative materials) but any laboratory using that specific material must have the results of the study available. This includes a full data package with the raw data that will allow an independent reviewer to verify each determination and calculation performed by the laboratory (see section 8.1.2.2.5, items (a)-(l)).


8.1.2.1.2 Sample matrices on which MS/MSD tests must be performed for nationwide use of an allowed modification:


(a) Effluent from a publicly owned treatment works (POTW).


(b) ASTM D5905 Standard Specification for Substitute Wastewater.


(c) Sewage sludge, if sewage sludge will be in the permit.


(d) ASTM D1141 Standard Specification for Substitute Ocean Water, if ocean water will be in the permit.


(e) Untreated and treated wastewaters up to a total of nine matrix types (see https://www.epa.gov/eg/industrial-effluent-guidelines for a list of industrial categories with existing effluent guidelines).


(i) At least one of the above wastewater matrix types must have at least one of the following characteristics:


(A) Total suspended solids greater than 40 mg/L.


(B) Total dissolved solids greater than 100 mg/L.


(C) Oil and grease greater than 20 mg/L.


(D) NaCl greater than 120 mg/L.


(E) CaCO3 greater than 140 mg/L.


(ii) Results of MS/MSD tests must meet QC acceptance criteria in section 8.3.


(f) A proficiency testing (PT) sample from a recognized provider, in addition to tests of the nine matrices (section 8.1.2.1.1).


8.1.2.2 The laboratory is required to maintain records of modifications made to this method. These records include the following, at a minimum:


8.1.2.2.1 The names, titles, and business street addresses, telephone numbers, and email addresses of the analyst(s) that performed the analyses and modification, and of the quality control officer that witnessed and will verify the analyses and modifications.


8.1.2.2.2 A list of analytes, by name and CAS Registry Number.


8.1.2.2.3 A narrative stating reason(s) for the modifications.


8.1.2.2.4 Results from all quality control (QC) tests comparing the modified method to this method, including:


(a) Calibration (section 7).


(b) Calibration verification/LCS (section 8.4).


(c) Initial demonstration of capability (section 8.2).


(d) Analysis of blanks (section 8.5).


(e) Matrix spike/matrix spike duplicate analysis (section 8.3).


(f) Laboratory control sample analysis (section 8.4).


8.1.2.2.5 Data that will allow an independent reviewer to validate each determination by tracing the instrument output (peak height, area, or other signal) to the final result. These data are to include:


(a) Sample numbers and other identifiers.


(b) Analysis dates and times.


(c) Analysis sequence/run chronology.


(d) Sample volume (Section 10).


(e) Sample dilution (Section 13.2).


(f) Instrument and operating conditions.


(g) Column (dimensions, material, etc).


(h) Operating conditions (temperature program, flow rate, etc).


(i) Detector (type, operating conditions, etc).


(j) Chromatograms, mass spectra, and other recordings of raw data.


(k) Quantitation reports, data system outputs, and other data to link the raw data to the results reported.


(l) A written Standard Operating Procedure (SOP).


8.1.2.2.6 Each individual laboratory wishing to use a given modification must perform the start-up tests in section 8.1.2 (e.g., DOC, MDL), with the modification as an integral part of this method prior to applying the modification to specific discharges. Results of the DOC must meet the QC acceptance criteria in Table 7 for the analytes of interest (section 1.3), and the MDLs must be equal to or lower than the MDLs in Table3 for the analytes of interest


8.1.3 Before analyzing samples, the laboratory must analyze a blank to demonstrate that interferences from the analytical system, labware, and reagents are under control. Each time a batch of samples is analyzed or reagents are changed, a blank must be analyzed as a safeguard against laboratory contamination. Requirements for the blank are given in section 8.5.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze samples to monitor and evaluate method and laboratory performance on the sample matrix. The procedure for spiking and analysis is given in section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through analysis of a quality control check sample (laboratory control sample, LCS; on-going precision and recovery sample, OPR) that the measurement system is in control. This procedure is given in section 8.4.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is given in section 8.8.


8.1.7 The large number of analytes tested in performance tests in this method present a substantial probability that one or more will fail acceptance criteria when many analytes are tested simultaneously, and a re-test is allowed if this situation should occur. If, however, continued re-testing results in further repeated failures, the laboratory must document and report the failures (e.g., as qualifiers on results), unless the failures are not required to be reported as determined by the regulatory/control authority. Results associated with a QC failure for an analyte regulated in a discharge cannot be used to demonstrate regulatory compliance. QC failures do not relieve a discharger or permittee of reporting timely results.


8.2 Initial demonstration of capability (DOC)—To establish the ability to generate acceptable recovery and precision, the laboratory must perform the DOC in sections 8.2.1 through 8.2.6 for the analytes of interest. The laboratory must also establish MDLs for the analytes of interest using the MDL procedure at 40 CFR part 136, appendix B. The laboratory’s MDLs must be equal to or lower than those listed in Table 1 for those analytes which list MDL values, or lower than one-third the regulatory compliance limit, whichever is greater. For MDLs not listed in Table 1, the laboratory must determine the MDLs using the MDL procedure at 40 CFR part 136, appendix B under the same conditions used to determine the MDLs for the analytes listed in Table 1. All procedures used in the analysis must be included in the DOC.


8.2.1 For the DOC, a QC check sample concentrate (LCS concentrate) containing each analyte of interest (section 1.3) is prepared in methanol. The QC check sample concentrate must be prepared independently from those used for calibration, but may be from the same source as the second-source standard used for calibration verification/LCS (sections 7.4 and 8.4). The concentrate should produce concentrations of the analytes of interest in water at the mid-point of the calibration range, and may be at the same concentration as the LCS (section 8.4).



Note:

QC check sample concentrates are no longer available from EPA.


8.2.2 Using a pipet or micro-syringe, prepare four LCSs by adding an appropriate volume of the concentrate to each of four aliquots of reagent water. The volume of reagent water must be the same as the volume that will be used for the sample, blank (section 8.5), and MS/MSD (section 8.3). A volume of 5 mL and a concentration of 20 µg/L were used to develop the QC acceptance criteria in Table 7. An alternative volume and sample concentration may be used, provided that all QC tests are performed and all QC acceptance criteria in this method are met. Also add an aliquot of the surrogate spiking solution (section 6.7) and internal standard spiking solution (section 7.3.1.3) to the reagent-water aliquots.


8.2.3 Analyze the four LCSs according to the method beginning in section 10.


8.2.4 Calculate the average percent recovery (X) and the standard deviation of the percent recovery (s) for each analyte using the four results.


8.2.5 For each analyte, compare s and X with the corresponding acceptance criteria for precision and recovery in Table 7. For analytes in Tables 1 and 2 not listed in Table 7, DOC QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 11 and 12). Alternatively, acceptance criteria for analytes not listed in Table 7 may be based on laboratory control charts. If s and X for all analytes of interest meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may begin. If any individual s exceeds the precision limit or any individual X falls outside the range for recovery, system performance is unacceptable for that analyte.



Note:

The large number of analytes in Tables 1 and 2 present a substantial probability that one or more will fail at least one of the acceptance criteria when many or all analytes are determined simultaneously. Therefore, the analyst is permitted to conduct a “re-test” as described in section 8.2.6.


8.2.6 When one or more of the analytes tested fail at least one of the acceptance criteria, repeat the test for only the analytes that failed. If results for these analytes pass, system performance is acceptable and analysis of samples and blanks may proceed. If one or more of the analytes again fail, system performance is unacceptable for the analytes that failed the acceptance criteria. Correct the problem and repeat the test (section 8.2). See section 8.1.7 for disposition of repeated failures.



Note:

To maintain the validity of the test and re-test, system maintenance and/or adjustment is not permitted between this pair of tests.


8.3 Matrix spike and matrix spike duplicate (MS/MSD)—The purpose of the MS/MSD requirement is to provide data that demonstrate the effectiveness of the method as applied to the samples in question by a given laboratory, and both the data user (discharger, permittee, regulated entity, regulatory/control authority, customer, other) and the laboratory share responsibility for provision of such data. The data user should identify the sample and the analytes of interest (section 1.3) to be spiked and provide sufficient sample volume to perform MS/MSD analyses. The laboratory must, on an ongoing basis, spike at least 5% of the samples in duplicate from each discharge being monitored to assess accuracy (recovery and precision). If direction cannot be obtained from the data user, the laboratory must spike at least one sample in duplicate per extraction batch of up to 20 samples with the analytes in Table 1. Spiked sample results should be reported only to the data user whose sample was spiked, or as requested or required by a regulatory/control authority, or in a permit.


8.3.1 If, as in compliance monitoring, the concentration of a specific analyte will be checked against a regulatory concentration limit, the concentration of the spike should be at that limit; otherwise, the concentration of the spike should be one to five times higher than the background concentration determined in section 8.3.2, at or near the mid-point of the calibration range, or at the concentration in the LCS (section 8.4) whichever concentration would be larger.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of the each analyte of interest. If necessary, prepare a new check sample concentrate (section 8.2.1) appropriate for the background concentration. Spike and analyze two additional sample aliquots, and determine the concentration after spiking (A1 and A2) of each analyte. Calculate the percent recoveries (P1 and P2) as 100 (A1−B)/T and 100 (A2−B)/T, where T is the known true value of the spike. Also calculate the relative percent difference (RPD) between the concentrations (A1 and A2) as 200 |A1−A2|/(A1 + A2). If necessary, adjust the concentrations used to calculate the RPD to account for differences in the volumes of the spiked aliquots.


8.3.3 Compare the percent recoveries (P1 and P2) and the RPD for each analyte in the MS/MSD aliquots with the corresponding QC acceptance criteria in Table 7. A laboratory may develop and apply QC acceptance criteria more restrictive than the criteria in Table 7, if desired.


8.3.3.1 If any individual P falls outside the designated range for recovery in either aliquot, or the RPD limit is exceeded, the result for the analyte in the unspiked sample is suspect. See Section 8.1.7 for disposition of failures.


8.3.3.2 The acceptance criteria in Table 7 were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the spike to background ratio approaches 5:1 (Reference 13) and is applied to spike concentrations of 20 µg/L and higher. If spiking is performed at a concentration lower than 20 µg/L, the laboratory must use the QC acceptance criteria in Table 7, the optional QC acceptance criteria calculated for the specific spike concentration in Table 8, or optional in-house criteria (Section 8.3.4). To use the acceptance criteria in Table 8: (1) Calculate recovery (X’) using the equation in Table 8, substituting the spike concentration (T) for C; (2) Calculate overall precision (S’) using the equation in Table 8, substituting X’ for X; (3) Calculate the range for recovery at the spike concentration as (100 X’/T) ± 2.44(100 S’/T)% (Reference 4). For analytes of interest in Tables 1 and 2 not listed in Table 7, QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 11 and 12). Alternatively, acceptance criteria may be based on laboratory control charts. In-house LCS QC acceptance criteria must be updated at least every two years.


8.3.4 After analysis of a minimum of 20 MS/MSD samples for each target analyte and surrogate, and if the laboratory chooses to develop and apply in-house QC limits, the laboratory should calculate and apply in-house QC limits for recovery and RPD of future MS/MSD samples (section 8.3). The QC limits for recovery are calculated as the mean observed recovery ± 3 standard deviations, and the upper QC limit for RPD is calculated as the mean RPD plus 3 standard deviations of the RPDs. The in-house QC limits must be updated at least every two years and re-established after any major change in the analytical instrumentation or process. If in-house QC limits are developed, at least 80% of the analytes tested in the MS/MSD must have in-house QC acceptance criteria that are tighter than those in Table 7 and the remaining analytes (those other than the analytes included in the 80%) must meet the acceptance criteria in Table 7. If an in-house QC limit for the RPD is greater than the limit in Table 7, then the limit in Table 7 must be used. Similarly, if an in-house lower limit for recovery is below the lower limit in Table 7, then the lower limit in Table 7 must be used, and if an in-house upper limit for recovery is above the upper limit in Table 7, then the upper limit in Table 7 must be used.


8.4 Calibration verification/laboratory control sample (LCS)—The working calibration curve or RF must be verified immediately after calibration and at the beginning of each 12-hour shift by the measurement of an LCS. The LCS must be from a source different from the source used for calibration (section 7.3.2.1), but may be the same as the sample prepared for the DOC (section 8.2.1).



Note:

The 12-hour shift begins after analysis of BFB, the LCS, and the blank, and ends 12 hours later. BFB, the LCS, and blank are outside of the 12-hour shift (Section 11.4). The MS and MSD are treated as samples and are analyzed within the 12-hour shift.


8.4.1 Prepare the LCS by adding QC check sample concentrate (section 8.2.1) to reagent water. Include all analytes of interest (Section 1.3) in the LCS. The volume of reagent water must be the same as the volume used for the sample, blank (Section 8.5), and MS/MSD (section 8.3). Also add an aliquot of the surrogate solution (Section 6.7) and internal standard solution (section 7.3.1.3). The concentration of the analytes in reagent water should be the same as the concentration in the DOC (section 8.2.2).


8.4.2 Analyze the LCS prior to analysis of field samples in the batch of samples analyzed during the 12-hour shift (see the Note at section 8.4). Determine the concentration (A) of each analyte. Calculate the percent recovery (Q) as 100 (A/T) %, where T is the true value of the concentration in the LCS.


8.4.3 Compare the percent recovery (Q) for each analyte with its corresponding QC acceptance criterion in Table 7. For analytes of interest in Tables 1 and 2 not listed in Table 7, use the QC acceptance criteria developed for the LCS (section 8.4.5). If the recoveries for all analytes of interest fall within their respective QC acceptance criteria, analysis of blanks and field samples may proceed. If any individual Q falls outside the range, proceed according to section 8.4.4.



Note:

The large number of analytes in Tables 1—2 present a substantial probability that one or more will fail the acceptance criteria when all analytes are tested simultaneously. Because a re-test is allowed in event of failure (sections 8.1.7 and 8.4.3), it may be prudent to analyze two LCSs together and evaluate results of the second analysis against the QC acceptance criteria only if an analyte fails the first test.


8.4.4 Repeat the test only for those analytes that failed to meet the acceptance criteria (Q). If these analytes now pass, system performance is acceptable and analysis of blanks and samples may proceed. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, repeat the test (section 8.4.2). using a fresh LCS (section 8.2.2) or an LCS prepared with a fresh QC check sample concentrate (section 8.2.1), or perform and document system repair. Subsequent to repair, repeat the calibration verification/LCS test (section 8.4). If the acceptance criteria for Q cannot be met, re-calibrate the instrument (section 7). See section 8.1.7 for disposition of repeated failures.



Note:

To maintain the validity of the test and re-test, system maintenance and/or adjustment is not permitted between the pair of tests.


8.4.5 After analysis of 20 LCS samples, and if the laboratory chooses to develop and apply in-house QC limits, the laboratory should calculate and apply in-house QC limits for recovery to future LCS samples (section 8.4). Limits for recovery in the LCS calculated as the mean recovery ±3 standard deviations. A minimum of 80% of the analytes tested for in the LCS must have QC acceptance criteria tighter than those in Table 7, and the remaining analytes (those other than the analytes included in the 80%) must meet the acceptance criteria in Table 7. If an in-house lower limit for recovery is lower than the lower limit in Table 7, the lower limit in Table 7 must be used, and if an in-house upper limit for recovery is higher than the upper limit in Table 7, the upper limit in Table 7 must be used. Many of the analytes and surrogates do not have acceptance criteria. The laboratory should use 60-140% as interim acceptance criteria for recoveries of spiked analytes that do not have recovery limits specified in Table 7, and least 80% of the analytes should meet the 60-140% interim criteria until in-house LCS limits are developed. Alternatively, acceptance criteria for analytes that do not have recovery limits in Table 7 may be based on laboratory control charts. In-house QC acceptance criteria must be updated at least every two years.


8.5 Blank—A blank must be analyzed prior to each 12-hour shift to demonstrate freedom from contamination. A blank must also be analyzed after a sample containing a high concentration of an analyte or potentially interfering compound to demonstrate freedom from carry-over.


8.5.1 Spike the internal standards and surrogates into the blank. Analyze the blank immediately after analysis of the LCS (Section 8.4) and prior to analysis of the MS/MSD and samples to demonstrate freedom from contamination.


8.5.2 If any analyte of interest is found in the blank: At a concentration greater than the MDL for the analyte, at a concentration greater than one-third the regulatory compliance limit, or at a concentration greater than one-tenth the concentration in a sample analyzed during the 12-hour shift (section 8.4), whichever is greater; analysis of samples must be halted and samples affected by the blank must be re-analyzed. If, however, continued re-testing results in repeated blank contamination, the laboratory must document and report the failures (e.g., as qualifiers on results), unless the failures are not required to be reported as determined by the regulatory/control authority. Results associated with blank contamination for an analyte regulated in a discharge cannot be used to demonstrate regulatory compliance. QC failures do not relieve a discharger or permittee of reporting timely results.


8.6 Surrogate recoveries—The laboratory must evaluate surrogate recovery data in each sample against its in-house surrogate recovery limits for surrogates that do not have acceptance criteria in Table 7. The laboratory may use 60-140% as interim acceptance criteria for recoveries for surrogates not listed in Table 5. At least 80% of the surrogates must meet the 60-140% interim criteria until in-house limits are developed. Alternatively, surrogate recovery limits may be developed from laboratory control charts.


8.6.1 Spike the surrogates into all samples, blanks, LCSs, and MS/MSDs. Compare surrogate recoveries against the QC acceptance criteria in Table 7. For surrogates in Table 5 without QC acceptance criteria in Table 7, and for other surrogates that may be used by the laboratory, limits must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 11 and 12). Alternatively, surrogate recovery limits may be developed from laboratory control charts. In-house QC acceptance criteria must be updated at least every two years.


8.6.2 If any recovery fails its criteria, attempt to find and correct the cause of the failure. See section 8.1.7 for disposition of failures.


8.7 Internal standard responses.


8.7.1 Calibration verification/LCS—The responses (GC peak heights or areas) of the internal standards in the calibration verification/LCS must be within 50% to 200% (1/2 to 2×) of their respective responses in the mid-point calibration standard. If they are not, repeat the LCS test using a fresh QC check sample (section 8.4.1) or perform and document system repair. Subsequent to repair, repeat the calibration verification/LCS test (section 8.4). If the responses are still not within 50% to 200%, re-calibrate the instrument (section 7) and repeat the calibration verification/LCS test.


8.7.2 Samples, blanks, and MS/MSDs—The responses (GC peak heights or areas) of each internal standard in each sample, blank, and MS/MSD must be within 50% to 200% (1/2 to 2×) of its respective response in the mid-point calibration standard. If, as a group, all internal standards are not within this range, perform and document system repair, repeat the calibration verification/LCS test (section 8.4), and re-analyze the affected samples. If a single internal standard is not within the 50% to 200% range, use an alternative internal standard for quantitation of the analyte referenced to the affected internal standard. It may be necessary to use the data system to calculate a new response factor from calibration data for the alternative internal standard/analyte pair. If an internal standard fails the 50-200% criteria and no analytes are detected in the sample, ignore the failure or report it if required by the regulatory/control authority.


8.8 As part of the QC program for the laboratory, control charts or statements of accuracy for wastewater samples must be assessed and records maintained periodically (see 40 CFR 136.7(c)(1)(viii)). After analysis of five or more spiked wastewater samples as in section 8.3, calculate the average percent recovery (PX) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent interval from PX−2sp to PX + 2sp. For example, if PX = 90% and sp = 10%, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each analyte on a regular basis (e.g., after each 5-10 new accuracy measurements). If desired, statements of accuracy for laboratory performance, independent of performance on samples, may be developed using LCSs.


8.9 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of environmental measurements. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Collect the sample as a grab sample in a glass container having a total volume of at least 25 mL. Fill the sample bottle just to overflowing in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. If needed, collect additional sample(s) for the MS/MSD (section 8.3).


9.2 Ice or refrigerate samples at ≤6 °C from the time of collection until analysis, but do not freeze. If residual chlorine is present, add sodium thiosulfate preservative (10 mg/40 mL is sufficient for up to 5 ppm Cl2) to the empty sample bottle just prior to shipping to the sampling site. Any method suitable for field use may be employed to test for residual chlorine (Reference 14). Field test kits are also available for this purpose. If sodium thiosulfate interferes in the determination of the analytes, an alternative preservative (e.g., ascorbic acid or sodium sulfite) may be used. If preservative has been added, shake the sample vigorously for one minute. Maintain the hermetic seal on the sample bottle until time of analysis.


9.3 If acrolein is to be determined, analyze the sample within 3 days. To extend the holding time to 14 days, acidify a separate sample to pH 4-5 with HCl using the procedure in section 9.7.


9.4 Experimental evidence indicates that some aromatic compounds, notably benzene, toluene, and ethyl benzene are susceptible to rapid biological degradation under certain environmental conditions (Reference 3). Refrigeration alone may not be adequate to preserve these compounds in wastewaters for more than seven days. To extend the holding time for aromatic compounds to 14 days, acidify the sample to approximately pH 2 using the procedure in section 9.7.


9.5 If halocarbons are to be determined, either use the acidified aromatics sample in section 9.4 or acidify a separate sample to a pH of about 2 using the procedure in section 9.7.


9.6 The ethers listed in Table 2 are prone to hydrolysis at pH 2 when a heated purge is used. Aqueous samples should not be acid preserved if these ethers are of interest, or if the alcohols they would form upon hydrolysis are of interest and the ethers are anticipated to present.


9.7 Sample acidification—Collect about 500 mL of sample in a clean container and adjust the pH of the sample to 4-5 for acrolein (section 9.3), or to about 2 for the aromatic compounds (section 9.4) by adding 1+1 HCl while swirling or stirring. Check the pH with narrow range pH paper. Fill a sample container as described in section 9.1. Alternatively, fill a precleaned vial (section 5.1.1) that contains approximately 0.25 mL of 1+1 HCl with sample as in section 9.1. If preserved using this alternative procedure, the pH of the sample can be verified to be

9.8 All samples must be analyzed within 14 days of collection (Reference 3), unless specified otherwise in sections 9.3-9.7.


10. Sample Purging and Gas Chromatography

10.1 The footnote to Table 3 gives the suggested GC column and operating conditions MDLs and MLs for many of the analytes are given in Table 1. Retention times for many of the analytes are given in Table 3. Sections 10.2 through 10.7 suggest procedures that may be used with a manual purge-and-trap system. Auto-samplers and other columns or chromatographic conditions may be used if requirements in this method are met. Prior to performing analyses, and between analyses, it may be necessary to bake the purge-and-trap and GC systems (section 3.3).


10.2 Attach the trap inlet to the purging device, and set the purge-and-trap system to purge. Open the syringe valve located on the purging device sample introduction needle.


10.3 Allow the sample to come to ambient temperature prior to pouring an aliquot into the syringe. Remove the plunger from a syringe and attach a closed syringe valve. Open the sample bottle (or standard) and carefully pour the sample into the syringe barrel to just short of overflowing. Replace the syringe plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume. Since this process of taking an aliquot destroys the validity of the sample for future analysis, the analyst should fill a second syringe at this time to protect against possible loss of data. Add the surrogate spiking solution (section 6.7) and internal standard spiking solution (section 7.3.1.3) through the valve bore, then close the valve. The surrogate and internal standards may be mixed and added as a single spiking solution. Autosamplers designed for purge-and-trap analysis of volatiles also may be used.


10.4 Attach the syringe valve assembly to the syringe valve on the purging device. Open the syringe valve and inject the sample into the purging chamber.


10.5 Close both valves and purge the sample at a temperature, flow rate, and duration sufficient to purge the less-volatile analytes onto the trap, yet short enough to prevent blowing the more-volatile analytes through the trap. The temperature, flow rate, and time should be determined by test. The same purge temperature, flow rate, and purge time must be used for all calibration, QC, and field samples.


10.6 After the purge, set the purge-and-trap system to the desorb mode, and begin the temperature program of the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to the desorb temperature while backflushing the trap with carrier gas at the flow rate and for the time necessary to desorb the analytes of interest. The optimum temperature, flow rate, and time should be determined by test. The same temperature, desorb time, and flow rate must be used for all calibration, QC, and field samples. If heating of the trap does not result in sharp peaks for the early eluting analytes, the GC column may be used as a secondary trap by cooling to an ambient or subambient temperature. To avoid carry-over and interferences, maintain the trap at the desorb temperature and flow rate until the analytes, interfering compounds, and excess water are desorbed. The optimum conditions should be determined by test.


10.7 Start MS data acquisition at the start of the desorb cycle and stop data collection when the analytes of interest, potentially interfering compounds, and water have eluted (see the footnote to Table 3 for conditions).


10.8 Cool the trap to the purge temperature and return the trap to the purge mode. When the trap is cool, the next sample can be analyzed.


11. Performance Tests

11.1 At the beginning of each 12-hour shift during which standards or samples will be analyzed, perform the tests in sections 11.2-11.3 to verify system performance. Use the instrument operating conditions in the footnotes to Table 3 for these performance tests. Alternative conditions may be used so as long as all QC requirements are met.


11.2 BFB—Inject 50 ng of BFB solution directly on the column. Alternatively, add BFB to reagent water or an aqueous standard such that 50 ng or less of BFB will be introduced into the GC. Analyze according to section 10. Confirm that all criteria in section 7.3.2.2 and Table 4 are met. If all criteria are not met, perform system repair, retune the mass spectrometer, and repeat the test until all criteria are met.


11.3 Verify calibration with the LCS (section 8.4) after the criteria for BFB are met (Reference 15) and prior to analysis of a blank or sample. After verification, analyze a blank (section 8.5) to demonstrate freedom from contamination and carry-over at the MDL. Tests for BFB, the LCS, and the blank are outside of the 12-hour shift, and the 12-hour shift includes samples and matrix spikes and matrix spike duplicates (section 8.4). The total time for analysis of BFB, the LCS, the blank, and the 12-hour shift must not exceed 14 hours.


12. Qualitative Identification

12.1 Identification is accomplished by comparison of results from analysis of a sample or blank with data stored in the GC/MS data system (section 7.3.2.3). Identification of an analyte is confirmed per sections 12.1.1 through 12.1.4.


12.1.1 The signals for the quantitation and secondary m/z’s stored in the data system (section 7.3.2.3) for each analyte of interest must be present and must maximize within the same two consecutive scans.


12.1.2 The retention time for the analyte should be within ± 10 seconds of the analyte in the LCS run at the beginning of the shift (section 8.4).



Note:

Retention time windows other than ± 10 seconds may be appropriate depending on the performance of the gas chromatograph or observed retention time drifts due to certain types of matrix effects. Relative retention time (RRT) may be used as an alternative to absolute retention times if retention time drift is a concern. RRT is a unitless quantity (see section 20.2), although some procedures refer to “RRT units” in providing the specification for the agreement between the RRT values in the sample and the LCS or other standard. When significant retention time drifts are observed, dilutions or spiked samples may help the analyst determine the effects of the matrix on elution of the target analytes and to assist in qualitative identification.


12.1.3 Either the background corrected EICP areas, or the corrected relative intensities of the mass spectral peaks at the GC peak maximum, must agree within 50% to 200% (
1/2 to 2 times) for the quantitation and secondary m/z’s in the reference mass spectrum stored in the data system (section 7.3.2.3), or from a reference library. For example, if a peak has an intensity of 20% relative to the base peak, the analyte is identified if the intensity of the peak in the sample is in the range of 10% to 40% of the base peak.


12.1.4 If the acquired mass spectrum is contaminated, or if identification is ambiguous, an experienced spectrometrist (section 1.6) must determine the presence or absence of the compound.


12.2 Structural isomers that produce very similar mass spectra should be identified as individual isomers if they have sufficiently different gas chromatographic retention times. Sufficient gas chromatographic resolution is achieved if the height of the valley between two isomer peaks is less than 50% of the average of the two peak heights. Otherwise, structural isomers are identified as isomeric pairs. The resolution should be verified on the mid-point concentration of the initial calibration as well as the laboratory designated continuing calibration verification level if closely eluting isomers are to be reported.


13. Calculations

13.1 When an analyte has been identified, quantitation of that analyte is based on the integrated abundance from the EICP of the primary characteristic m/z in Table 5 or 6. Calculate the concentration using the response factor (RF) determined in section 7.3.3 and Equation 2. If a calibration curve was used, calculate the concentration using the regression equation for the curve. If the concentration of an analyte exceeds the calibration range, dilute the sample by the minimum amount to bring the concentration into the calibration range, and re-analyze. Determine a dilution factor (DF) from the amount of the dilution. For example, if the extract is diluted by a factor of 2, DF = 2.



Where:

Cs = Concentration of the analyte in the sample, and the other terms are as defined in Section 7.3.3.

13.2 Reporting of results


As noted in section 1.4.1, EPA has promulgated this method at 40 CFR part 136 for use in wastewater compliance monitoring under the National Pollutant Discharge Elimination System (NPDES). The data reporting practices described here are focused on such monitoring needs and may not be relevant to other uses of this method.


13.2.1 Report results for wastewater samples in µg/L without correction for recovery. (Other units may be used if required by a permit.) Report all QC data with the sample results.


13.2.2 Reporting level. Unless otherwise specified in by a regulatory authority or in a discharge permit, results for analytes that meet the identification criteria are reported down to the concentration of the ML established by the laboratory through calibration of the instrument (see section 7.3.2 and the glossary for the derivation of the ML). EPA considers the terms “reporting limit,” “limit of quantitation,” “quantitation limit,” and “minimum level” to be synonymous.


13.2.2.1 Report a result for each analyte in each field sample or QC standard at or above the ML to 3 significant figures. Report a result for each analyte found in each field sample or QC standard below the ML as “

13.2.2.2 In addition to reporting results for samples and blanks separately, the concentration of each analyte in a blank associated with the sample may be subtracted from the result for that sample, but only if requested or required by a regulatory authority or in a permit. In this case, both the sample result and the blank result must be reported together.


13.2.2.3 Report a result for an analyte found in a sample that has been diluted at the least dilute level at which the area at the quantitation m/z is within the calibration range (i.e., above the ML for the analyte) and the MS/MSD recovery and RPD are within their respective QC acceptance criteria (Table 7). This may require reporting results for some analytes from different analyses.


13.2.3 Results from tests performed with an analytical system that is not in control (i.e., that does not meet acceptance criteria for any of the QC test in this method) must be documented and reported (e.g., as a qualifier on results), unless the failure is not required to be reported as determined by the regulatory/control authority. Results associated with a QC failure cannot be used to demonstrate regulatory compliance. QC failures do not relieve a discharger or permittee of reporting timely results. If the holding time would be exceeded for a re-analysis of the sample, the regulatory/control authority should be consulted for disposition.


14. Method Performance

14.1 This method was tested by 15 laboratories using reagent water, drinking water, surface water, and industrial wastewaters spiked at six concentrations over the range 5-600 µg/L (References 4 and 16). Single-operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the analyte and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 8.


14.2 As noted in section 1.1, this method was validated through an interlaboratory study conducted in the early 1980s. However, the fundamental chemistry principles used in this method remain sound and continue to apply.


15. Pollution Prevention

15.1 Pollution prevention encompasses any technique that reduces or eliminates the quantity or toxicity of waste at the point of generation. Many opportunities for pollution prevention exist in laboratory operations. EPA has established a preferred hierarchy of environmental management techniques that places pollution prevention as the management option of first choice. Whenever feasible, the laboratory should use pollution prevention techniques to address waste generation. When wastes cannot be reduced at the source, the Agency recommends recycling as the next best option.


15.2 The analytes in this method are used in extremely small amounts and pose little threat to the environment when managed properly. Standards should be prepared in volumes consistent with laboratory use to minimize the disposal of excess volumes of expired standards.


15.3 For information about pollution prevention that may be applied to laboratories and research institutions, consult “Less is Better: Laboratory Chemical Management for Waste Reduction,” available from the American Chemical Society’s Department of Governmental Relations and Science Policy, 1155 16th Street NW., Washington, DC 20036, 202-872-4477.


16. Waste Management

16.1 The laboratory is responsible for complying with all Federal, State, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions, and to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations. An overview of requirements can be found in Environmental Management Guide for Small Laboratories (EPA 233-B-98-001).


16.2 Samples at pH 12, are hazardous and must be handled and disposed of as hazardous waste, or neutralized and disposed of in accordance with all federal, state, and local regulations. It is the laboratory’s responsibility to comply with all federal, state, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions. The laboratory using this method has the responsibility to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations. For further information on waste management, see “The Waste Management Manual for Laboratory Personnel,” also available from the American Chemical Society at the address in Section 15.3.


16.3 Many analytes in this method decompose above 500 °C. Low-level waste such as absorbent paper, tissues, and plastic gloves may be burned in an appropriate incinerator. Gross quantities of neat or highly concentrated solutions of toxic or hazardous chemicals should be packaged securely and disposed of through commercial or governmental channels that are capable of handling these types of wastes.


16.4 For further information on waste management, consult “Waste Management Manual for Laboratory Personnel and Less is Better-Laboratory Chemical Management for Waste Reduction,” available from the American Chemical Society’s Department of Government Relations and Science Policy, 1155 16th Street NW., Washington, DC 20036, 202-872-4477.


17. References

1. Bellar, T.A. and Lichtenberg, J.J. “Determining Volatile Organics at Microgram-per-Litre Levels by Gas Chromatography,” Journal American Water Works Association, 66: 739 (1974).


2. “Sampling and Analysis Procedures for Screening of Industrial Effluents for Priority Pollutants,” U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1977, Revised April 1977.


3. Bellar, T.A. and Lichtenberg, J.J. “Semi-Automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds,” Measurement of Organic Pollutants in Water and Wastewater, C.E. Van Hall, editor, American Society for Testing and Materials, Philadelphia, PA. Special Technical Publication 686, 1978.


4. “EPA Method Study 29 EPA Method 624-Purgeables,” EPA 600/4-84-054, National Technical Information Service, PB84-209915, Springfield, Virginia 22161, June 1984.


5. 40 CFR part 136, appendix B.


6. “Method Detection Limit for Methods 624 and 625,” Olynyk, P., Budde, W.L., and Eichelberger, J.W. Unpublished report, May 14, 1980.


7. “Carcinogens-Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.


8. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).


9. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 7th Edition, 2003.


10. 40 CFR 136.6(b)(5)(x).


11. 40 CFR 136.6(b)(2)(i).


12. Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes in Wastewater and Drinking Water (EPA-821-B-98-003) March 1999.


13. Provost, L.P. and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983).


14. 40 CFR 136.3(a), Table IB, Chlorine—Total residual.


15. Budde, W.L. and Eichelberger, J.W. “Performance Tests for the Evaluation of Computerized Gas Chromatography/Mass Spectrometry Equipment and Laboratories,” EPA-600/4-80-025, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, April 1980.


16. “Method Performance Data for Method 624,” Memorandum from R. Slater and T. Pressley, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, January 17, 1984.


18. Tables

Table 1—Purgeables
1

Analyte
CAS Registry No.
MDL (µg/L)
2
ML (µg/L)
3
Acrolein107-02-8
Acrylonitrile107-13-1
Benzene71-43-24.413.2
Bromodichloromethane75-27-42.26.6
Bromoform75-25-24.714.1
Bromomethane74-83-9
Carbon tetrachloride56-23-52.88.4
Chlorobenzene108-90-76.018.0
Chloroethane75-00-3
2-Chloroethylvinyl ether110-75-8
Chloroform67-66-31.64.8
Chloromethane74-87-3
Dibromochloromethane124-48-13.19.3
1,2-Dichlorobenzene95-50-1
1,3-Dichlorobenzene541-73-1
1,4-Dichlorobenzene106-46-7
1,1-Dichloroethane75-34-34.714.1
1,2-Dichloroethane107-06-22.88.4
1,1-Dichloroethene75-35-42.88.4
trans-1,2-Dichloroethene156-60-51.64.8
1,2-Dichloropropane78-87-56.018.0
cis-1,3-Dichloropropene10061-01-55.015.0
trans-1,3-Dichloropropene10061-02-6
Ethyl benzene100-41-47.221.6
Methylene chloride75-09-22.88.4
1,1,2,2-Tetrachloroethane79-34-56.920.7
Tetrachloroethene127-18-44.112.3
Toluene108-88-36.018.0
1,1,1-Trichloroethane71-55-63.811.4
1,1,2-Trichloroethane79-00-55.015.0
Trichloroethene79-01-61.95.7
Vinyl chloride75-01-4


1 All the analytes in this table are Priority Pollutants (40 CFR part 423, appendix A).


2 MDL values from the 1984 promulgated version of Method 624.


3 ML = Minimum Level—see Glossary for definition and derivation.


Table 2—Additional Purgeables

Analyte
CAS Registry
Acetone
1		67-64-1
Acetonitrile
2		75-05-8
Acrolein107-02-8
Acrylonitrile107-13-1
Allyl alcohol
1		107-18-6
Allyl chloride107-05-1
t-Amyl ethyl ether (TAEE)919-94-8
t-Amyl methyl ether (TAME)994-058
Benzyl chloride100-44-7
Bromoacetone
2		598-31-2
Bromobenzene108-86-1
Bromochloromethane74-97-5
1,3-Butadiene106-99-0
n-Butanol
1		71-36-3
2-Butanone (MEK)
1 2		78-93-3
t-Butyl alcohol (TBA)75-65-0
n-Butylbenzene104-51-8
sec-Butylbenzene135-98-8
t-Butylbenzene98-06-6
t-Butyl ethyl ether (ETBE)637-92-3
Carbon disulfide75-15-0
Chloral hydrate
2		302-17-0
Chloroacetonitrile
1		107-14-2
1-Chlorobutane109-69-3
Chlorodifluoromethane75-45-6
2-Chloroethanol
2		107-07-3
bis (2-Chloroethyl) sulfide
2		505-60-2
1-Chlorohexanone20261-68-1
Chloroprene (2-chloro-1,3-butadiene)126-99-8
3-Chloropropene107-05-1
3-Chloropropionitrile542-76-7
2-Chlorotoluene95-49-8
4-Chlorotoluene106-43-4
Crotonaldehyde
1 2		123-73-9
Cyclohexanone108-94-1
1,2-Dibromo-3-chloropropane96-12-8
1,2-Dibromoethane106-93-4
Dibromomethane74-95-3
cis-1,4-Dichloro-2-butene1476-11-5
trans-1,4-Dichloro-2-butene110-57-6
cis-1,2-Dichloroethene156-59-2
Dichlorodifluoromethane75-71-8
1,3-Dichloropropane142-28-9
2,2-Dichloropropane590-20-7
1,3-Dichloro-2-propanol
2		96-23-1
1,1-Dichloropropene563-58-6
cis-1,3-Dichloropropene10061-01-5
1:2,3:4-Diepoxybutane1464-53-5
Diethyl ether60-29-7
Diisopropyl ether (DIPE)108-20-3
1,4-Dioxane
2		123-91-1
Epichlorohydrin
2		106-89-8
Ethanol
2		64-17-5
Ethyl acetate
2		141-78-6
Ethyl methacrylate97-63-2
Ethylene oxide
2		75-21-8
Hexachlorobutadiene87-63-3
Hexachloroethane67-72-1
2-Hexanone
2		591-78-6
Iodomethane74-88-4
Isobutyl alcohol
1		78-83-1
Isopropylbenzene98-82-8
p-Isopropyltoluene99-87-6
Methacrylonitrile
2		126-98-7
Methanol
2		67-56-1
Malonitrile
2		109-77-3
Methyl acetate79-20-9
Methyl acrylate96-33-3
Methyl cyclohexane108-87-2
Methyl iodide74-88-4
Methyl methacrylate78-83-1
4-Methyl-2-pentanone (MIBK)
2		108-10-1
Methyl-t-butyl ether (MTBE)1634-04-4
Naphthalene91-20-3
Nitrobenzene98-95-3
N-Nitroso-di-n-butylamine
2		924-16-3
2-Nitropropane79-46-9
Paraldehyde
2		123-63-7
Pentachloroethane
2		76-01-7
Pentafluorobenzene363-72-4
2-Pentanone
2		107-19-7
2-Picoline
2		109-06-8
1-Propanol
1		71-23-8
2-Propanol
1		67-63-0
Propargyl alcohol
2		107-19-7
beta-Propiolactone
2		57-58-8
Propionitrile (ethyl cyanide)
1		107-12-0
n-Propylamine107-10-8
n-Propylbenzene103-65-1
Pyridine
2		110-86-1
Styrene100-42-5
1,1,1,2-Tetrachloroethane630-20-6
Tetrahydrofuran109-99-9
o-Toluidine
2		95-53-4
1,2,3-Trichlorobenzene87-61-6
Trichlorofluoromethane75-69-4
1,2,3-Trichloropropane96-18-4
1,2,3-Trimethylbenzene526-73-8
1,2,4-Trimethylbenzene95-63-6
1,3,5-Trimethylbenzene108-67-8
Vinyl acetate108-05-4
m-Xylene
3		108-38-3
o-Xylene
3		95-47-6
p-Xylene
3		106-42-3
m+o-Xylene
3		179601-22-0
m+p-Xylene
3		179601-23-1
o+p-Xylene
3		136777-61-2


1 Determined at a purge temperature of 80 °C.


2 May be detectable at a purge temperature of 80 °C.


3 Determined in combination separated by GC column. Most GC columns will resolve o-xylene from m+p-xylene. Report using the CAS number for the individual xylene or the combination, as determined.


Table 3—Example Retention Times

Analyte
Retention time

(min)
Chloromethane3.68
Vinyl chloride3.92
Bromomethane4.50
Chloroethane4.65
Trichlorofluoromethane5.25
Diethyl ether5.88
Acrolein6.12
1,1-Dichloroethene6.30
Acetone6.40
Iodomethane6.58
Carbon disulfide6.72
3-Chloropropene6.98
Methylene chloride7.22
Acrylonitrile7.63
trans-1,2-Dichloroethene7.73
1,1-Dichloroethane8.45
Vinyl acetate8.55
Allyl alcohol8.58
2-Chloro-1,3-butadiene8.65
Methyl ethyl ketone9.50
cis-1,2-Dichloroethene9.50
Ethyl cyanide9.57
Methacrylonitrile9.83
Chloroform10.05
1,1,1-Trichloroethane10.37
Carbon tetrachloride10.70
Isobutanol10.77
Benzene10.98
1,2-Dichloroethane11.00
Crotonaldehyde11.45
Trichloroethene12.08
1,2-Dichloropropane12.37
Methyl methacrylate12.55
p-Dioxane12.63
Dibromomethane12.65
Bromodichloromethane12.95
Chloroacetonitrile13.27
2-Chloroethylvinyl ether13.45
cis-1,3-Dichloropropene13.65
4-Methyl-2-pentanone13.83
Toluene14.18
trans-1,3-Dichloropropene14.57
Ethyl methacrylate14.70
1,1,2-Trichloroethane14.93
1,3-Dichloropropane15.18
Tetrachloroethene15.22
2-Hexanone15.30
Dibromochloromethane15.68
1,2-Dibromoethane15.90
Chlorobenzene16.78
Ethylbenzene16.82
1,1,1,2-Tetrachloroethane16.87
m+p-Xylene17.08
o-Xylene17.82
Bromoform18.27
Bromofluorobenzene18.80
1,1,2,2-Tetrachloroethane18.98
1,2,3-Trichloropropane19.08
trans-1,4-Dichloro-2-butene19.12

Column: 75 m x 0.53 mm ID x 3.0 µm wide-bore DB-624

Conditions: 40 °C for 4 min, 9 °C/min to 200 °C, 20 °C/min (or higher) to 250 °C, hold for 20 min at 250 °C to remove water.

Carrier gas flow rate: 6-7 mL/min at 40 °C.

Inlet split ratio: 3:1.

Interface split ratio: 7:2.


Table 4—BFB Key m/z Abundance Criteria
1

m/z
Abundance criteria
5015-40% of m/z 95.
7530-60% of m/z 95.
95Base Peak, 100% Relative Abundance.
965-9% of m/z 95.
173
174>50% of m/z 95.
1755-9% of m/z 174.
176>95% but
1775-9% of m/z 176.


1 Abundance criteria are for a quadrupole mass spectrometer. Alternative tuning criteria from other published EPA reference methods may be used, provided method performance is not adversely affected. Alternative tuning criteria specified by an instrument manufacturer may also be used for another type of mass spectrometer, or for an alternative carrier gas, provided method performance is not adversely affected.


Table 5—Suggested Surrogate and Internal Standards

Analyte
Retention time (min)
1
Primary m/z
Secondary

m/z’s
Benzene-d610.9584
4-Bromofluorobenzene18.8095174, 176
Bromochloromethane9.8812849, 130, 51
2-Bromo-1-chloropropane14.807779, 156
2-Butanone-d59.3377
Chloroethane-d54.6371
Chloroform-
13C		10.0086
1,2-Dichlorobenzene-d4152
1,4-Dichlorobutane18.575590, 92
1,2-Dichloroethane-d410.88102
1,1-Dichloroethene-d26.3065
1,2-Dichloropropane-d612.2767
trans-1,3-Dichloropropene-d414.5079
1,4-Difluorobenzene11463, 88
Ethylbenzene-d1016.7798
Fluorobenzene9670
2-Hexanone-d515.3063
Pentafluorobenzene168
1,1,2,2-Tetrachloroethane-d218.9384
Toluene-d814.13100
Vinyl chloride-d33.8765


1 For chromatographic conditions, see the footnote to Table 3.


Table 6—Characteristic m/z’s for Purgeable Organics

Analyte
Primary m/z
Secondary m/z’s
Acrolein5655 and 58.
Acrylonitrile5352 and 51.
Chloromethane5052.
Bromomethane9496.
Vinyl chloride6264.
Chloroethane6466.
Methylene chloride8449, 51, and 86.
Trichlorofluoromethane101103.
1,1-Dichloroethene9661 and 98.
1,1-Dichloroethane6365, 83, 85, 98, and 100.
trans-1,2-Dichloroethene9661 and 98.
Chloroform8385.
1,2-Dichloroethane9862, 64, and 100.
1,1,1-Trichloroethane9799, 117, and 119.
Carbon tetrachloride117119 and 121.
Bromodichloromethane83127, 85, and 129.
1,2-Dichloropropane63112, 65, and 114.
trans-1,3-Dichloropropene7577.
Trichloroethene13095, 97, and 132.
Benzene78
Dibromochloromethane127129, 208, and 206.
1,1,2-Trichloroethane9783, 85, 99, 132, and 134.
cis-1,3-Dichloropropene7577.
2-Chloroethylvinyl ether10663 and 65.
Bromoform173171, 175, 250, 252, 254, and 256.
1,1,2,2-Tetrachloroethane16883, 85, 131, 133, and 166.
Tetrachloroethene164129, 131, and 166.
Toluene9291.
Chlorobenzene112114.
Ethyl benzene10691.
1,3-Dichlorobenzene146148 and 111.
1,2-Dichlorobenzene146148 and 111.
1,4-Dichlorobenzene146148 and 111.

Table 7—LCS (Q), DOC (s and X), and MS/MSD (P and RPD) Acceptance Criteria
1

Analyte
Range for Q

(%)
Limit for s

(%)
Range for X

(%)
Range for P1, P2

(%)
Limit for RPD
Acrolein60-1403050-15040-16060
Acrylonitrile60-1403050-15040-16060
Benzene65-1353375-12537-15161
Benzene-d6
Bromodichloromethane65-1353450-14035-15556
Bromoform70-1302557-15645-16942
Bromomethane15-18590D-206D-24261
2-Butanone-d5
Carbon tetrachloride70-1302665-12570-14041
Chlorobenzene65-1352982-13737-16053
Chloroethane40-1604742-20214-23078
Chloroethane-d5
2-Chloroethylvinyl etherD-225130D-252D-30571
Chloroform70-1353268-12151-13854
Chloroform-
13C
ChloromethaneD-205472D-230D-27360
Dibromochloromethane70-1353069-13353-14950
1,2-Dichlorobenzene65-1353159-17418-19057
1,2-Dichlorobenzene-d4
1,3-Dichlorobenzene70-1302475-14459-15643
1,4-Dichlorobenzene65-1353159-17418-19057
1,1-Dichloroethane70-1302471-14359-15540
1,2-Dichloroethane70-1302972-13749-15549
1,2-Dichloroethane-d4
1,1-Dichloroethene50-1504019-212D-23432
1,1-Dichloroethene-d2
trans-1,2-Dichloroethene70-1302768-14354-15645
1,2-Dichloropropane35-1656919-181D-21055
1,2-Dichloropropane-d6
cis-1,3-Dichloropropene25-175795-195D-22758
trans-1,3-Dichloropropene50-1505238-16217-18386
trans-1,3-Dichloropropene-d4
Ethyl benzene60-1403475-13437-16263
2-Hexanone-d5
Methylene chloride60-140192D-205D-22128
1,1,2,2-Tetrachloroethane60-1403668-13646-15761
1,1,2,2-Tetrachloroethane-d2
Tetrachloroethene70-1302365-13364-14839
Toluene70-1302275-13447-15041
Toluene-d8
1,1,1-Trichloroethane70-1302169-15152-16236
1,1,2-Trichloroethane70-1302775-13652-15045
Trichloroethene65-1352975-13870-15748
Trichlorofluoromethane50-1505045-15817-18184
Vinyl chloride5-195100D-218D-25166
Vinyl chloride-d3


1 Criteria were calculated using an LCS concentration of 20 µg/L.

Q = Percent recovery in calibration verification/LCS (section 8.4).

s = Standard deviation of percent recovery for four recovery measurements (section 8.2.4).

X = Average percent recovery for four recovery measurements (section 8.2.4).

P = Percent recovery for the MS or MSD (section 8.3.3).

D = Detected; result must be greater than zero.

Notes:

1. Criteria for pollutants are based upon the method performance data in Reference 4. Where necessary, limits have been broadened to assure applicability to concentrations below those used to develop Table 7.

2. Criteria for surrogates are from EPA CLP SOM01.2D.


Table 8—Recovery and Precision as Functions of Concentration

Analyte
Recovery, X′

(µg/L)
Single analyst precision, sr′

(µg/L)
Overall

precision, S′

(µg/L)
Benzene0.93C+2.0020.26 X−1.740.25 X−1.33
Bromodichloromethane1.03C−1.580.15 X+0.590.20 X+1.13
Bromoform1.18C−2.350.12 X+0.360.17 X+1.38
Bromomethane
a		1.00C0.43 X0.58 X
Carbon tetrachloride1.10C−1.680.12 X+0.250.11 X+0.37
Chlorobenzene0.98C+2.280.16 X−0.090.26 X−1.92
Chloroethane1.18C+0.810.14 X+2.780.29 X+1.75
2-Chloroethylvinyl ether
a		1.00C0.62 X0.84 X
Chloroform0.93C+0.330.16 X+0.220.18 X+0.16
Chloromethane1.03C+0.810.37 X+2.140.58 X+0.43
Dibromochloromethane1.01C−0.030.17 X−0.180.17 X+0.49
1,2-Dichlorobenzene
b		0.94C+4.470.22 X−1.450.30 X−1.20
1,3-Dichlorobenzene1.06C+1.680.14 X−0.480.18 X−0.82
1,4-Dichlorobenzene
b		0.94C+4.470.22 X−1.450.30 X−1.20
1,1-Dichloroethane1.05C+0.360.13 X−0.050.16 X+0.47
1,2-Dichloroethane1.02C+0.450.17 X−0.320.21 X−0.38
1,1-Dichloroethene1.12C+0.610.17 X+1.060.43 X−0.22
trans-1,2,-Dichloroethene1.05C+0.030.14 X−+0.090.19 X−+0.17
1,2-Dichloropropane
a		1.00C0.33 X0.45 X
cis-1,3-Dichloropropene
a		1.00C0.38 X0.52 X
trans-1,3-Dichloropropene
a		1.00C0.25 X0.34 X
Ethyl benzene0.98C+2.480.14 X+1.000.26 X−1.72
Methylene chloride0.87C+1.880.15 X+1.070.32 X+4.00
1,1,2,2-Tetrachloroethane0.93C+1.760.16 X+0.690.20 X+0.41
Tetrachloroethene1.06C+0.600.13 X−0.180.16 X−0.45
Toluene0.98C+2.030.15 X−0.710.22 X−1.71
1,1,1-Trichloroethane1.06C+0.730.12 X−0.150.21 X−0.39
1,1,2-Trichloroethane0.95C+1.710.14 X+0.020.18 X+0.00
Trichloroethene1.04C+2.270.13 X+0.360.12 X+0.59
Trichlorofluoromethane0.99C+0.390.33 X−1.480.34 X−0.39
Vinyl chloride1.00C0.48 X0.65 X

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

Sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X, in µg/L.

C = True value for the concentration, in µg/L.

X = Average recovery found for measurements of samples containing a concentration of C, in µg/L.


a Estimates based upon the performance in a single laboratory (References 4 and 16).


b Due to coelutions, performance statements for these isomers are based upon the sums of their concentrations.


19. Glossary

These definitions and purposes are specific to this method, but have been conformed to common usage to the extent possible.


19.1 Units of weight and measure and their abbreviations.


19.1.1 Symbols.


°C degrees Celsius

µg microgram

µL microliter


> greater than

% percent

19.1.2 Abbreviations (in alphabetical order).


cm centimeter

g gram

h hour

ID inside diameter

in. inch

L liter

m mass

mg milligram

min minute

mL milliliter

mm millimeter

ms millisecond

m/z mass-to-charge ratio

N normal; gram molecular weight of solute divided by hydrogen equivalent of solute, per liter of solution

ng nanogram

pg picogram

ppb part-per-billion

ppm part-per-million

ppt part-per-trillion

psig pounds-per-square inch gauge

v/v volume per unit volume

w/v weight per unit volume

19.2 Definitions and acronyms (in alphabetical order).


Analyte—A compound tested for by this method. The analytes are listed in Tables 1 and 2.


Analyte of interest—An analyte of interest is an analyte required to be determined by a regulatory/control authority or in a permit, or by a client.


Analytical batch—The set of samples analyzed on a given instrument during a 12-hour period that begins with analysis of a calibration verification/LCS. See section 8.4.


Blank—An aliquot of reagent water that is treated exactly as a sample including exposure to all glassware, equipment, solvents, reagents, internal standards, and surrogates that are used with samples. The blank is used to determine if analytes or interferences are present in the laboratory environment, the reagents, or the apparatus. See section 8.5.


Calibration—The process of determining the relationship between the output or response of a measuring instrument and the value of an input standard. Historically, EPA has referred to a multi-point calibration as the “initial calibration,” to differentiate it from a single-point calibration verification.


Calibration standard—A solution prepared from stock solutions and/or a secondary standards and containing the analytes of interest, surrogates, and internal standards. The calibration standard is used to calibrate the response of the GC/MS instrument against analyte concentration.


Calibration verification standard—The laboratory control sample (LCS) used to verify calibration. See Section 8.4.


Descriptor—In SIM, the beginning and ending retention times for the RT window, the m/z’s sampled in the RT window, and the dwell time at each m/z.


Extracted ion current profile (EICP)—The line described by the signal at a given m/z.


Field duplicates—Two samples collected at the same time and place under identical conditions, and treated identically throughout field and laboratory procedures. Results of analyses of field duplicates provide an estimate of the precision associated with sample collection, preservation, and storage, as well as with laboratory procedures.


Field blank—An aliquot of reagent water or other reference matrix that is placed in a sample container in the field, and treated as a sample in all respects, including exposure to sampling site conditions, storage, preservation, and all analytical procedures. The purpose of the field blank is to determine if the field or sample transporting procedures and environments have contaminated the sample.


GC—Gas chromatograph or gas chromatography.


Internal standard—A compound added to a sample in a known amount and used as a reference for quantitation of the analytes of interest and surrogates. Internal standards are listed in Table 5. Also see Internal standard quantitation.


Internal standard quantitation—A means of determining the concentration of an analyte of interest (Tables 1 and 2) by reference to a compound added to a sample and not expected to be found in the sample.


DOC—Initial demonstration of capability (DOC; section 8.2); four aliquots of reagent water spiked with the analytes of interest and analyzed to establish the ability of the laboratory to generate acceptable precision and recovery. A DOC is performed prior to the first time this method is used and any time the method or instrumentation is modified.


Laboratory control sample (LCS; laboratory fortified blank (LFB); on-going precision and recovery sample; OPR)—An aliquot of reagent water spiked with known quantities of the analytes of interest and surrogates. The LCS is analyzed exactly like a sample. Its purpose is to assure that the results produced by the laboratory remain within the limits specified in this method for precision and recovery. In this method, the LCS is synonymous with a calibration verification sample (See sections 7.4 and 8.4).


Laboratory fortified sample matrix—See Matrix spike.


Laboratory reagent blank—See Blank.


Matrix spike (MS) and matrix spike duplicate (MSD) (laboratory fortified sample matrix and duplicate)—Two aliquots of an environmental sample to which known quantities of the analytes of interest and surrogates are added in the laboratory. The MS/MSD are prepared and analyzed exactly like a field sample. Their purpose is to quantify any additional bias and imprecision caused by the sample matrix. The background concentrations of the analytes in the sample matrix must be determined in a separate aliquot and the measured values in the MS/MSD corrected for background concentrations.


May—This action, activity, or procedural step is neither required nor prohibited.


May not—This action, activity, or procedural step is prohibited.


Method blank (laboratory reagent blank)—See Blank.


Method detection limit (MDL)—A detection limit determined by the procedure at 40 CFR part 136, appendix B. The MDLs determined by EPA in the original version of the method are listed in Table 1. As noted in Sec. 1.4, use the MDLs in Table 1 in conjunction with current MDL data from the laboratory actually analyzing samples to assess the sensitivity of this procedure relative to project objectives and regulatory requirements (where applicable).


Minimum level (ML)—The term “minimum level” refers to either the sample concentration equivalent to the lowest calibration point in a method or a multiple of the method detection limit (MDL), whichever is higher. Minimum levels may be obtained in several ways: They may be published in a method; they may be based on the lowest acceptable calibration point used by a laboratory; or they may be calculated by multiplying the MDL in a method, or the MDL determined by a laboratory, by a factor of 3. For the purposes of NPDES compliance monitoring, EPA considers the following terms to be synonymous: “quantitation limit,” “reporting limit,” and “minimum level.”


MS—Mass spectrometer or mass spectrometry.


Must—This action, activity, or procedural step is required.


m/z—The ratio of the mass of an ion (m) detected in the mass spectrometer to the charge (z) of that ion.


Quality control sample (QCS)—A sample containing analytes of interest at known concentrations. The QCS is obtained from a source external to the laboratory or is prepared from standards obtained from a different source than the calibration standards.


The purpose is to check laboratory performance using test materials that have been prepared independent of the normal preparation process.


Reagent water—Water demonstrated to be free from the analytes of interest and potentially interfering substances at the MDLs for the analytes in this method.


Regulatory compliance limit (or regulatory concentration limit)—A limit on the concentration or amount of a pollutant or contaminant specified in a nationwide standard, in a permit, or otherwise established by a regulatory/control authority.


Relative retention time (RRT)—The ratio of the retention time of an analyte to the retention time of its associated internal standard. RRT compensates for small changes in the GC temperature program that can affect the absolute retention times of the analyte and internal standard. RRT is a unitless quantity.


Relative standard deviation (RSD)—The standard deviation times 100 divided by the mean. Also termed “coefficient of variation.”


RF—Response factor. See section 7.3.3.


RSD—See relative standard deviation.


Safety Data Sheet (SDS)—Written information on a chemical’s toxicity, health hazards, physical properties, fire, and reactivity, including storage, spill, and handling precautions that meet the requirements of OSHA, 29 CFR 1910.1200(g) and appendix D to § 1910.1200. United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS), third revised edition, United Nations, 2009.


Selected Ion Monitoring (SIM)—An MS technique in which a few m/z’s are monitored. When used with gas chromatography, the m/z’s monitored are usually changed periodically throughout the chromatographic run to correlate with the characteristic m/z’s for the analytes, surrogates, and internal standards as they elute from the chromatographic column. The technique is often used to increase sensitivity and minimize interferences.


Signal-to-noise ratio (S/N)—The height of the signal as measured from the mean (average) of the noise to the peak maximum divided by the width of the noise.


SIM—See Selection Ion Monitoring.


Should—This action, activity, or procedural step is suggested but not required.


Stock solution—A solution containing an analyte that is prepared using a reference material traceable to EPA, the National Institute of Science and Technology (NIST), or a source that will attest to the purity and authenticity of the reference material.


Surrogate—A compound unlikely to be found in a sample, and which is spiked into sample in a known amount before purge-and-trap. The surrogate is quantitated with the same procedures used to quantitate the analytes of interest. The purpose of the surrogate is to monitor method performance with each sample.


VOA—Volatile organic analysis: e.g., the analysis performed by this method.


Method 625.1—Base/Neutrals and Acids by GC/MS

1. Scope and Application

1.1 This method is for determination of semivolatile organic pollutants in industrial discharges and other environmental samples by gas chromatography combined with mass spectrometry (GC/MS), as provided under 40 CFR 136.1. This revision is based on a previous protocol (Reference 1), on the basic revision promulgated October 26, 1984, and on an interlaboratory method validation study (Reference 2). Although this method was validated through an interlaboratory study conducted in the early 1980s, the fundamental chemistry principles used in this method remain sound and continue to apply.


1.2 The analytes that may be qualitatively and quantitatively determined using this method and their CAS Registry numbers are listed in Tables 1 and 2. The method may be extended to determine the analytes listed in Table 3; however, extraction or gas chromatography of some of these analytes may make quantitative determination difficult. For example, benzidine is subject to oxidative losses during extraction and/or solvent concentration. Under the alkaline conditions of the extraction, alpha-BHC, gamma-BHC, endosulfan I and II, and endrin are subject to decomposition. Hexachlorocyclopentadiene is subject to thermal decomposition in the inlet of the gas chromatograph, chemical reaction in acetone solution, and photochemical decomposition. N-nitrosodiphenylamine and other nitrosoamines may decompose in the gas chromatographic inlet. The sample may be extracted at neutral pH if necessary to overcome these or other decomposition problems that could occur at alkaline or acidic pH. EPA also has provided other methods (e.g., Method 607—Nitrosamines) that may be used for determination of some of these analytes. EPA encourages use of Method 625.1 to determine additional compounds amenable to extraction and GC/MS.


1.3 The large number of analytes in Tables 1-3 of this method makes testing difficult if all analytes are determined simultaneously. Therefore, it is necessary to determine and perform quality control (QC) tests for the “analytes of interest” only. Analytes of interest are those required to be determined by a regulatory/control authority or in a permit, or by a client. If a list of analytes is not specified, the analytes in Tables 1 and 2 must be determined, at a minimum, and QC testing must be performed for these analytes. The analytes in Tables 1 and 2, and some of the analytes in Table 3 have been identified as Toxic Pollutants (40 CFR 401.15), expanded to a list of Priority Pollutants (40 CFR part 423, appendix A).


1.4 In this revision to Method 625, the pesticides and polychlorinated biphenyls (PCBs) have been moved from Table 1 to Table 3 (Additional Analytes) to distinguish these analytes from the analytes required in quality control tests (Tables 1 and 2). QC acceptance criteria for pesticides and PCBs have been retained in Table 6 and may continue to be applied if desired, or if requested or required by a regulatory/control authority or in a permit. Method 608.3 should be used for determination of pesticides and PCBs. However, if pesticides and/or PCBs are to be determined, an additional sample must be collected and extracted using the pH adjustment and extraction procedures specified in Method 608.3. Method 1668C may be useful for determination of PCBs as individual chlorinated biphenyl congeners, and Method 1699 may be useful for determination of pesticides. At the time of writing of this revision, Methods 1668C and 1699 had not been approved for use at 40 CFR part 136. The screening procedure for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) contained in the version of Method 625 promulgated October 26, 1984 has been replaced with procedures for selected ion monitoring (SIM), and 2,3,7,8-TCDD may be determined using the SIM procedures. However, EPA Method 613 or 1613B should be used for analyte-specific determination of 2,3,7,8-TCDD because of the focus of these methods on this compound. Methods 613 and 1613B are approved for use at 40 CFR part 136.


1.5 Method detection limits (MDLs; Reference 3) for the analytes in Tables 1, 2, and 3 are listed in those tables. These MDLs were determined in reagent water (Reference 4). Advances in analytical technology, particularly the use of capillary (open-tubular) columns, allowed laboratories to routinely achieve MDLs for the analytes in this method that are 2-10 times lower than those in the version promulgated in 1984. The MDL for an analyte in a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.


1.5.1 EPA has promulgated this method at 40 CFR part 136 for use in wastewater compliance monitoring under the National Pollutant Discharge Elimination System (NPDES). The data reporting practices described in section 15.2 are focused on such monitoring needs and may not be relevant to other uses of the method.


1.5.2 This method includes “reporting limits” based on EPA’s “minimum level” (ML) concept (see the glossary in section 22). Tables 1, 2, and 3 contain MDL values and ML values for many of the analytes.


1.6 This method is performance-based. It may be modified to improve performance (e.g., to overcome interferences or improve the accuracy of results) provided all performance requirements are met.


1.6.1 Examples of allowed method modifications are described at 40 CFR 136.6. Other examples of allowed modifications specific to this method, including solid-phase extraction (SPE) are described in section 8.1.2.


1.6.2 Any modification beyond those expressly permitted at 40 CFR 136.6 or in section 8.1.2 of this method shall be considered a major modification subject to application and approval of an alternate test procedure under 40 CFR 136.4 and 136.5.


1.6.3 For regulatory compliance, any modification must be demonstrated to produce results equivalent or superior to results produced by this method when applied to relevant wastewaters (section 8.3).


1.7 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph/mass spectrometer and in the interpretation of mass spectra. Each laboratory that uses this method must demonstrate the ability to generate acceptable results using the procedure in Section 8.2.


1.8 Terms and units of measure used in this method are given in the glossary at the end of the method.


2. Summary of Method

2.1 A measured volume of sample, sufficient to meet an MDL or reporting limit, is serially extracted with methylene chloride at pH 11-13 and again at a pH less than 2 using a separatory funnel or continuous liquid/liquid extractor.


2.2 The extract is concentrated to a volume necessary to meet the required compliance or detection limit, and analyzed by GC/MS. Qualitative identification of an analyte in the extract is performed using the retention time and the relative abundance of two or more characteristic masses (m/z’s). Quantitative analysis is performed using the internal standard technique with a single characteristic m/z.


3. Contamination and Interferences

3.1 Solvents, reagents, glassware, and other sample processing labware may yield artifacts, elevated baselines, or matrix interferences causing misinterpretation of chromatograms and mass spectra. All materials used in the analysis must be demonstrated to be free from contamination and interferences by analyzing blanks initially and with each extraction batch (samples started through the extraction process in a given 24-hour period, to a maximum of 20 samples—see Glossary for detailed definition), as described in Section 8.5. Specific selection of reagents and purification of solvents by distillation in all-glass systems may be required. Where possible, labware is cleaned by extraction or solvent rinse, or baking in a kiln or oven.


3.2 Glassware must be scrupulously cleaned (Reference 5). Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and reagent water. The glassware should then be drained dry, and heated at 400 °C for 15-30 minutes. Some thermally stable materials, such as PCBs, may require higher temperatures and longer baking times for removal. Solvent rinses with pesticide quality acetone, hexane, or other solvents may be substituted for heating. Do not heat volumetric labware above 90 °C. After drying and cooling, store inverted or capped with solvent-rinsed or baked aluminum foil in a clean environment to prevent accumulation of dust or other contaminants.


3.3 Matrix interferences may be caused by contaminants co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. Interferences extracted from samples high in total organic carbon (TOC) may result in elevated baselines, or by enhancing or suppressing a signal at or near the retention time of an analyte of interest. Analyses of the matrix spike and duplicate (section 8.3) may be useful in identifying matrix interferences, and gel permeation chromatography (GPC; Section 11.1) and sulfur removal (section 11.2) may aid in eliminating these interferences. EPA has provided guidance that may aid in overcoming matrix interferences (Reference 6).


3.4 In samples that contain an inordinate number of interferences, the use of chemical ionization (CI) or triple quadrupole (MRM) mass spectrometry may make identification easier. Tables 4 and 5 give characteristic CI and MRM m/z’s for many of the analytes covered by this method. The use of CI or MRM mass spectrometry may be utilized to support electron ionization (EI) mass spectrometry or as a primary method for identification and quantification. While the use of these enhanced techniques is encouraged, it is not required.


4. Safety

4.1 Hazards associated with each reagent used in this method have not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of safety data sheets (SDSs, OSHA, 29 CFR 1910.1200(g)) should also be made available to all personnel involved in sample handling and chemical analysis. Additional references to laboratory safety are available and have been identified (References 7-9) for the information of the analyst.


4.2 The following analytes covered by this method have been tentatively classified as known or suspected human or mammalian carcinogens: Benzo(a)anthracene, benzidine, 3,3′-dichlorobenzidine, benzo(a)pyrene, alpha-BHC, beta-BHC, delta-BHC, gamma-BHC, Dibenz(a,h)-anthracene, N-nitrosodimethylamine, 4,4′-DDT, and PCBs. Other compounds in Table 3 may also be toxic. Primary standards of toxic compounds should be prepared in a chemical fume hood, and a NIOSH/MESA approved toxic gas respirator should be worn when handling high concentrations of these compounds.


4.3 This method allows the use of hydrogen as a carrier gas in place of helium (section 5.6.1.2). The laboratory should take the necessary precautions in dealing with hydrogen, and should limit hydrogen flow at the source to prevent buildup of an explosive mixture of hydrogen in air.


5. Apparatus and Materials


Note:

Brand names, suppliers, and part numbers are for illustration purposes only. No endorsement is implied. Equivalent performance may be achieved using equipment and materials other than those specified here. Demonstrating that the equipment and supplies used in the laboratory achieves the required performance is the responsibility of the laboratory. Suppliers for equipment and materials in this method may be found through an on-line search. Please do not contact EPA for supplier information.


5.1 Sampling equipment, for discrete or composite sampling.


5.1.1 Grab sample bottle—amber glass bottle large enough to contain the necessary sample volume, fitted with a fluoropolymer-lined screw cap. Foil may be substituted for fluoropolymer if the sample is not corrosive. If amber bottles are not available, protect samples from light. Unless pre-cleaned, the bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.


5.1.2 Automatic sampler (optional)—the sampler must incorporate a pre-cleaned glass sample container. Samples must be kept refrigerated at ≤6 °C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, rinse the compressible tubing with methanol, followed by repeated rinsing with reagent water, to minimize the potential for sample contamination. An integrating flow meter is required to collect flow-proportioned composites.


5.2 Glassware.


5.2.1 Separatory funnel—Size appropriate to hold sample volume and extraction solvent volume, and equipped with fluoropolymer stopcock.


5.2.2 Drying column—Chromatographic column, approximately 400 mm long by 19 mm ID, with coarse frit, or equivalent, sufficient to hold 15 g of anhydrous sodium sulfate.


5.2.3 Concentrator tube, Kuderna-Danish—10 mL, graduated (Kontes 570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. A ground glass stopper is used to prevent evaporation of extracts.


5.2.4 Evaporative flask, Kuderna-Danish—500 mL (Kontes 57001-0500 or equivalent). Attach to concentrator tube with springs.



Note:

Use of a solvent recovery system with the K-D or other solvent evaporation apparatus is strongly recommended.


5.2.5 Snyder column, Kuderna-Danish—Three-ball macro (Kontes 503000-0121 or equivalent).


5.2.6 Snyder column, Kuderna-Danish—Two-ball micro (Kontes 569001-0219 or equivalent).


5.2.7 Vials—10-15 mL, amber glass, with Teflon-lined screw cap.


5.2.8 Continuous liquid-liquid extractor—Equipped with fluoropolymer or glass connecting joints and stopcocks requiring no lubrication. (Hershberg-Wolf Extractor, Ace Glass Company, Vineland, NJ, P/N 6848-20, or equivalent.)


5.2.9 In addition to the glassware listed above, the laboratory should be equipped with all necessary pipets, volumetric flasks, beakers, and other glassware listed in this method and necessary to perform analyses successfully.


5.3 Boiling chips—Approximately 10/40 mesh, glass, silicon carbide, or equivalent. Heat to 400 °C for 30 minutes, or solvent rinse or Soxhlet extract with methylene chloride.


5.4 Water bath—Heated, with concentric ring cover, capable of temperature control (±2 °C). The bath should be used in a hood.


5.5 Balances.


5.5.1 Analytical, capable of accurately weighing 0.1 mg.


5.5.2 Top loading, capable of accurately weighing 10 mg.


5.6 GC/MS system.


5.6.1 Gas chromatograph (GC)—An analytical system complete with a temperature programmable gas chromatograph and all required accessories, including syringes and analytical columns.


5.6.1.1 Injection port—Can be split, splitless, temperature programmable vaporization split/splitless (PTV), solvent-purge, large-volume, on-column, backflushed, or other. An autosampler is highly recommended because it injects volumes more precisely than volumes injected manually.


5.6.1.2 Carrier gas—Helium or hydrogen. Data in the tables in this method were obtained using helium carrier gas. If hydrogen is used, analytical conditions may need to be adjusted for optimum performance, and calibration and all QC tests must be performed with hydrogen carrier gas. See Section 4.3 for precautions regarding the use of hydrogen as a carrier gas.


5.6.2 GC column—See the footnotes to Tables 4 and 5. Other columns or column systems may be used provided all requirements in this method are met.


5.6.3 Mass spectrometer—Capable of repetitively scanning from 35-450 Daltons (amu) every two seconds or less, utilizing a 70 eV (nominal) electron energy in the electron impact ionization mode, and producing a mass spectrum which meets all the criteria in Table 9A or 9B when 50 ng or less of decafluorotriphenyl phosphine (DFTPP; CAS 5074-71-5; bis(pentafluorophenyl) phenyl phosphine) is injected into the GC.


5.6.4 GC/MS interface—Any GC to MS interface that meets all performance requirements in this method may be used.


5.6.5 Data system—A computer system must be interfaced to the mass spectrometer that allows the continuous acquisition and storage of mass spectra acquired throughout the chromatographic program. The computer must have software that allows searching any GC/MS data file for specific m/z’s (masses) and plotting m/z abundances versus time or scan number. This type of plot is defined as an extracted ion current profile (EICP). Software must also be available that allows integrating the abundance at any EICP between specified time or scan number limits.


5.7 Automated gel permeation chromatograph (GPC).


5.7.1 GPC column—150-700 mm long × 21-25 mm ID, packed with 70 g of SX-3 Biobeads; Bio-Rad Labs, or equivalent.


5.7.2 Pump, injection valve, UV detector, and other apparatus necessary to meet the requirements in this method.


5.8 Nitrogen evaporation device—Equipped with a water bath than can be maintained at 30-45 °C; N-Evap, Organomation Associates, or equivalent.


5.9 Muffle furnace or kiln—Capable of baking glassware or sodium sulfate in the range of 400-450 °C.


6. Reagents

6.1 Reagent water—Reagent water is defined as water in which the analytes of interest and interfering compounds are not detected at the MDLs of the analytes of interest.


6.2 Sodium hydroxide solution (10 N)—Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.


6.3 Sodium thiosulfate—(ACS) granular.


6.4 Sulfuric acid (1+1)—Slowly add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.


6.5 Acetone, methanol, methylene chloride, 2-propanol—High purity pesticide quality, or equivalent, demonstrated to be free of the analytes of interest and interferences (Section 3). Purification of solvents by distillation in all-glass systems may be required.


6.6 Sodium sulfate—(ACS) granular, anhydrous, rinsed or Soxhlet extracted with methylene chloride (20 mL/g), baked in a shallow tray at 450 °C for one hour minimum, cooled in a desiccator, and stored in a pre-cleaned glass bottle with screw cap that prevents moisture from entering.


6.7 Stock standard solutions (1.00 µg/µL)—Stock standard solutions may be prepared from pure materials, or purchased as certified solutions. Traceability must be to the National Institute of Standards and Technology (NIST) or other national or international standard, when available. Stock solution concentrations alternate to those below may be used. Because of the toxicity of some of the compounds, primary dilutions should be prepared in a hood, and a NIOSH/MESA approved toxic gas respirator should be worn when high concentrations of neat materials are handled. The following procedure may be used to prepare standards from neat materials.


6.7.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in pesticide quality methanol or other suitable solvent and dilute to volume in a 10-mL volumetric flask. Larger volumes may be used at the convenience of the laboratory. When compound purity is assayed to be 96% or greater, the weight may be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards may be used at any concentration if they are certified by the manufacturer or by an independent source.


6.7.2 Unless stated otherwise in this method, store non-aqueous standards in fluoropolymer-lined screw-cap, or heat-sealed, glass containers, in the dark at −20 to −10 °C. Store aqueous standards; e.g., the aqueous LCS (section 8.4.1), in the dark at ≤ 6 °C, but do not freeze. Standards prepared by the laboratory may be stored for up to one year, except when comparison with QC check standards indicates that a standard has degraded or become more concentrated due to evaporation, or unless the laboratory has data on file to prove stability for a longer period. Commercially prepared standards may be stored until the expiration date provided by the vendor, except when comparison with QC check standards indicates that a standard has degraded or become more concentrated due to evaporation, or unless the laboratory has data from the vendor on file to prove stability for a longer period.


6.8 Surrogate standard spiking solution.


6.8.1 Select a minimum of three surrogate compounds from Table 8 that most closely match the recovery of the analytes of interest. For example, if all analytes tested are considered acids, use surrogates that have similar chemical attributes. Other compounds may be used as surrogates so long as they do not interfere in the analysis. If only one or two analytes are determined, one or two surrogates may be used.


6.8.2 Prepare a solution containing each selected surrogate such that the concentration in the sample would match the concentration in the mid-point calibration standard. For example, if the midpoint of the calibration is 100 µg/L, prepare the spiking solution at a concentration of 100 µg/mL in methanol. Addition of 1.00 mL of this solution to 1000 mL of sample will produce a concentration of 100 µg/L of the surrogate. Alternate volumes and concentrations appropriate to the response of the GC/MS instrument or for selective ion monitoring (SIM) may be used, if desired. Store per section 6.7.2.


6.9 Internal standard spiking solution.


6.9.1 Select three or more internal standards similar in chromatographic behavior to the analytes of interest. Internal standards are listed in Table 8. Suggested internal standards are: 1,4-dichlorobenzene-d4; naphthalene-d8; acenaphthene-d10; phenanthrene-d10; chrysene-d12; and perylene-d12. The laboratory must demonstrate that measurement of the internal standards is not affected by method or matrix interferences (see also section 7.3.4).


6.9.2 Prepare the internal standards at a concentration of 10 mg/mL in methylene chloride or other suitable solvent. When 10 µL of this solution is spiked into a 1-mL extract, the concentration of the internal standards will be 100 µg/mL. A lower concentration appropriate to the response of the GC/MS instrument or for SIM may be used, if desired. Store per section 6.7.3.


6.9.3 To assure accurate analyte identification, particularly when SIM is used, it may be advantageous to include more internal standards than those suggested in section 6.9.1. An analyte will be located most accurately if its retention time relative to an internal standard is in the range of 0.8 to 1.2.


6.10 DFTPP standard—Prepare a solution of DFTPP in methanol or other suitable solvent such that 50 ng or less will be injected (see section 13.2). An alternative concentration may be used to compensate for specific injection volumes or to assure that the operating range of the instrument is not exceeded, so long as the total injected is 50 ng or less. Include benzidine and pentachlorophenol in this solution such that ≤100 ng of benzidine and ≤50 ng of pentachlorophenol will be injected.


6.11 Quality control check sample concentrate—See section 8.2.1.


6.12 GPC calibration solution.


6.12.1 Prepare a methylene chloride solution to contain corn oil, bis(2-ethylhexyl) phthalate (BEHP), perylene, and sulfur at the concentrations in section 6.12.2, or at concentrations appropriate to the response of the detector.



Note:

Sulfur does not readily dissolve in methylene chloride, but is soluble in warm corn oil. The following procedure is suggested for preparation of the solution.


6.12.2 Weigh 8 mg sulfur and 2.5 g corn oil into a 100-mL volumetric flask and warm to dissolve the sulfur. Separately weigh 100 mg BEHP, 20 mg pentachlorophenol, and 2 mg perylene and add to flask. Bring to volume with methylene chloride and mix thoroughly.


6.12.3 Store the solution in an amber glass bottle with a fluoropolymer-lined screw cap at 0-6 °C. Protect from light. Refrigeration may cause the corn oil to precipitate. Before use, allow the solution to stand at room temperature until the corn oil dissolves, or warm slightly to aid in dissolution. Replace the solution every year, or more frequently if the response of a component changes.


6.13 Sulfur removal—Copper foil or powder (bright, non-oxidized), or tetrabutylammonium sulfite (TBA sulfite).


6.13.1 Copper foil, or powder—Fisher, Alfa Aesar 42455-18, 625 mesh, or equivalent. Cut copper foil into approximately 1-cm squares. Copper must be activated before it may be used, as described below:


6.13.1.1 Place the quantity of copper needed for sulfur removal (section 11.2.1.3) in a ground-glass-stoppered Erlenmeyer flask or bottle. Cover the foil or powder with methanol.


6.13.1.2 Add HCl dropwise (0.5-1.0 mL) while swirling, until the copper brightens.


6.13.1.3 Pour off the methanol/HCl and rinse 3 times with reagent water to remove all traces of acid, then 3 times with acetone, then 3 times with hexane.


6.13.1.4 For copper foil, cover with hexane after the final rinse. Store in a stoppered flask under nitrogen until used. For the powder, dry on a rotary evaporator or under a stream of nitrogen. Store in a stoppered flask under nitrogen until used. Inspect the copper foil or powder before each use. It must have a bright, non-oxidized appearance to be effective. Copper foil or powder that has oxidized may be reactivated using the procedure described above.


6.13.2 Tetrabutylammonium sodium sulfite (TBA sodium sulfite).


6.13.2.1 Tetrabutylammonium hydrogen sulfate, [CH3(CH2)3]4NHSO4.


6.13.2.2 Sodium sulfite, Na2SO3.


6.13.2.3 Dissolve approximately 3 g tetrabutylammonium hydrogen sulfate in 100 mL of reagent water in an amber bottle with fluoropolymer-lined screw cap. Extract with three 20-mL portions of hexane and discard the hexane extracts.


6.13.2.4 Add 25 g sodium sulfite to produce a saturated solution. Store at room temperature. Replace after 1 month.


6.14 DDT and endrin decomposition (breakdown) solution—Prepare a solution containing endrin at a concentration of 1 µg/mL and 4,4′-DDT at a concentration of 2 µg/mL, in isooctane or hexane. A 1-µL injection of this standard will contain 1 nanogram (ng) of endrin and 2 ng of DDT. The concentration of the solution may be adjusted by the laboratory to accommodate other injection volumes such that the same masses of the two analytes are introduced into the instrument.


7. Calibration

7.1 Establish operating conditions equivalent to those in the footnote to Table 4 or 5 for the base/neutral or acid fraction, respectively. If a combined base/neutral/acid fraction will be analyzed, use the conditions in the footnote to Table 4. Alternative temperature program and flow rate conditions may be used. It is necessary to calibrate the GC/MS for the analytes of interest (Section 1.3) only.


7.2 Internal standard calibration.


7.2.1 Prepare calibration standards for the analytes of interest and surrogates at a minimum of five concentration levels by adding appropriate volumes of one or more stock standards to volumetric flasks. One of the calibration standards should be at a concentration at or below the ML specified in Table 1, 2, or 3, or as specified by a regulatory/control authority or in a permit. The ML value may be rounded to a whole number that is more convenient for preparing the standard, but must not exceed the ML in Table 1, 2, or 3 for those analytes which list ML values. Alternatively, the laboratory may establish a laboratory ML for each analyte based on the concentration in a nominal whole-volume sample that is equivalent to the concentration of the lowest calibration standard in a series of standards produced in the laboratory or obtained from a commercial vendor. The laboratory’s ML must not exceed the ML in Table 1, 2, or 3, and the resulting calibration must meet the acceptance criteria in Section 7.2.3, based on the RSD, RSE, or R
2. The concentrations of the other calibration standards should correspond to the expected range of concentrations found in real samples or should define the working range of the GC/MS system for full-scan and/or SIM operation, as appropriate. A minimum of six concentration levels is required for a second order, non-linear (e.g., quadratic; ax
2 + bx + c = 0) calibration (section 7.2.3). Calibrations higher than second order are not allowed. To each calibration standard or standard mixture, add a known constant volume of the internal standard solution (section 6.9), and dilute to volume with methylene chloride.



Note:

The large number of analytes in Tables 1 through 3 may not be soluble or stable in a single solution; multiple solutions may be required if a large number of analytes are to be determined simultaneously.


7.2.1.1 Prior to analysis of the calibration standards, inject the DFTPP standard (Section 6.10) and adjust the scan rate of the mass spectrometer to produce a minimum of 5 mass spectra across the DFTPP GC peak. Adjust instrument conditions until the DFTPP criteria in Table 9A or 9B are met. Calculate peak tailing factors for benzidine and pentachlorophenol. Calculation of the tailing factor is illustrated in Figure 1. The tailing factor for benzidine and pentachlorophenol must be <2; otherwise, adjust instrument conditions and either replace the column or break off a short section of the front end of the column, and repeat the test. Once the scan conditions are established, they must be used for analyses of all standards, blanks, and samples.



Note:

The DFTPP spectrum may be evaluated by summing the intensities of the m/z’s across the GC peak, subtracting the background at each m/z in a region of the chromatogram within 20 scans of but not including any part of, the DFTPP peak. The DFTPP spectrum may also be evaluated by fitting a Gaussian to each m/z and using the intensity at the maximum for each Gaussian or by integrating the area at each m/z and using the integrated areas. Other means may be used for evaluation of the DFTPP spectrum so long as the spectrum is not distorted to meet the criteria in Table 9A or 9B.


7.2.1.2 Analyze the mid-point combined base/neutral and acid calibration standard and enter or review the retention time, relative retention time, mass spectrum, and quantitation m/z in the data system for each analyte of interest, surrogate, and internal standard. If additional analytes (Table 3) are to be quantified, include these analytes in the standard. The mass spectrum for each analyte must be comprised of a minimum of 2 m/z’s (Tables 4 and 5); 3 to 5 m/z’s assure more reliable analyte identification. Suggested quantitation m/z’s are shown in Tables 4 and 5 as the primary m/z. If an interference occurs at the primary m/z, use one of the secondary m/z’s or an alternate m/z. A single m/z only is required for quantitation.


7.2.1.3 For SIM operation, determine the analytes in each descriptor, the quantitation m/z for each analyte (the quantitation m/z can be the same as for full-scan operation; section 7.2.1.2), the dwell time on each m/z for each analyte, and the beginning and ending retention time for each descriptor. Analyze the verification standard in scan mode to verify m/z’s and establish retention times for the analytes. There must be a minimum of two m/z’s for each analyte to assure analyte identification. To maintain sensitivity, the number of m/z’s in a descriptor should be limited. For example, for a descriptor with 10 m/z’s and a chromatographic peak width of 5 sec, a dwell time of 100 ms at each m/z would result in a scan time of 1 second and provide 5 scans across the GC peak. The quantitation m/z will usually be the most intense peak in the mass spectrum. The quantitation m/z and dwell time may be optimized for each analyte. The acquisition table used for SIM must take into account the mass defect (usually less than 0.2 Dalton) that can occur at each m/z monitored. Refer to the footnotes to Table 4 or 5 for establishing operating conditions and to section 7.2.1.1 for establishing scan conditions.


7.2.1.4 For combined scan and SIM operation, set up the scan segments and descriptors to meet requirements in sections 7.2.1.1-7.2.1.3. Analyze unfamiliar samples in the scan mode to assure that the analytes of interest are determined.


7.2.2 Analyze each calibration standard according to section 12 and tabulate the area at the quantitation m/z against concentration for each analyte of interest, surrogate, and internal standard. If an interference is encountered, use a secondary m/z (Table 4 or 5) for quantitation. Calculate a response factor (RF) for each analyte of interest at each concentration using Equation 1.



where:

As = Area of the characteristic m/z for the analyte of interest or surrogate.

Ais = Area of the characteristic m/z for the internal standard.

Cis = Concentration of the internal standard (µg/mL).

Cs = Concentration of the analyte of interest or surrogate (µg/mL).

7.2. Calculate the mean (average) and relative standard deviation (RSD) of the responses factors. If the RSD is less than 35%, the RF can be assumed to be invariant and the average RF can be used for calculations. Alternatively, the results can be used to fit a linear or quadratic regression of response ratios, As/Ais, vs. concentration ratios Cs/Cis. If used, the regression must be weighted inversely proportional to concentration. The coefficient of determination (R
2; Reference 10) of the weighted regression must be greater than 0.920 (this value roughly corresponds to the RSD limit of 35%). Alternatively, the relative standard error (Reference 11) may be used as an acceptance criterion. As with the RSD, the RSE must be less than 35%. If an RSE less than 35% cannot be achieved for a quadratic regression, system performance is unacceptable and the system must be adjusted and re-calibrated.



Note:

Using capillary columns and current instrumentation, it is quite likely that a laboratory can calibrate the target analytes in this method and achieve a linearity metric (either RSD or RSE) well below 35%. Therefore, laboratories are permitted to use more stringent acceptance criteria for calibration than described here, for example, to harmonize their application of this method with those from other sources.


7.3 Calibration verification—The RF or calibration curve must be verified immediately after calibration and at the beginning of each 12-hour shift, by analysis of a standard at or near the concentration of the mid-point calibration standard (section 7.2.1). The standard(s) must be obtained from a second manufacturer or a manufacturer’s batch prepared independently from the batch used for calibration. Traceability must be to a national standard, when available. Include the surrogates (section 6.8) in this solution. It is necessary to verify calibration for the analytes of interest (section 1.3) only.



Note:

The 12-hour shift begins after the DFTPP (section 13.1) and DDT/endrin tests (if DDT and endrin are to be determined), and after analysis of the calibration verification standard. The 12-hour shift ends 12 hours later. The DFTPP, DDT/endrin, and calibration verification tests are outside of the 12-hour shift.


7.3.1 Analyze the calibration verification standard(s) beginning in section 12. Calculate the percent recovery of each analyte. Compare the recoveries for the analytes of interest against the acceptance criteria for recovery (Q) in Table 6, and the recoveries for the surrogates against the acceptance criteria in Table 8. If recovery of the analytes of interest and surrogates meet acceptance criteria, system performance is acceptable and analysis of samples may continue. If any individual recovery is outside its limit, system performance is unacceptable for that analyte.



Note:

The large number of analytes in Tables 6 and 8 present a substantial probability that one or more will fail acceptance criteria when all analytes are tested simultaneously.


7.3.2 When one or more analytes fail acceptance criteria, analyze a second aliquot of the calibration verification standard and compare ONLY those analytes that failed the first test (section 7.3.1) with their respective acceptance criteria. If these analytes now pass, system performance is acceptable and analysis of samples may continue. A repeat failure of any analyte that failed the first test, however, will confirm a general problem with the measurement system. If this occurs, repair the system (section 7.2.1.1) and repeat the test (section 7.3.1), or prepare a fresh calibration standard and repeat the test. If calibration cannot be verified after maintenance or injection of the fresh calibration standard, re-calibrate the instrument.



Note:

If it is necessary to perform a repeat verification test frequently; i.e., perform two tests in order to pass, it may be prudent to perform two injections in succession and review the results, rather than perform one injection, review the results, then perform the second injection if results from the first injection fail. To maintain the validity of the test and re-test, system maintenance and/or adjustment is not permitted between the injections.


7.3.3 Many of the analytes in Table 3 do not have QC acceptance criteria in Table 6, and some of the surrogates in Table 8 do not have acceptance criteria. If calibration is to be verified and other QC tests are to be performed for these analytes, acceptance criteria must be developed and applied. EPA has provided guidance for development of QC acceptance criteria (References 12 and 13). Alternatively, analytes that do not have acceptance criteria in Table 6 or Table 8 may be based on laboratory control charts, or 60 to 140% may be used.


7.3.4 Internal standard responses—Verify that detector sensitivity has not changed by comparing the response of each internal standard in the calibration verification standard (section 7.3) to the response of the respective internal standard in the midpoint calibration standard (section 7.2.1). The peak areas or heights of the internal standards in the calibration verification standard must be within 50% to 200% (1/2 to 2x) of their respective peak areas or heights in the mid-point calibration standard. If not, repeat the calibration verification test using a fresh calibration verification standard (7.3), or perform and document system repair. Subsequent to repair, repeat the calibration verification test (section 7.3.1). If the responses are still not within 50% to 200%, re-calibrate the instrument (section 7.2.2) and repeat the calibration verification test.


8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and ongoing analysis of spiked samples and blanks to evaluate and document data quality (40 CFR 136.7). The laboratory must maintain records to document the quality of data generated. Results of ongoing performance tests are compared with established QC acceptance criteria to determine if the results of analyses meet performance requirements of this method. When results of spiked samples do not meet the QC acceptance criteria in this method, a quality control check sample (laboratory control sample; LCS) must be analyzed to confirm that the measurements were performed in an in-control mode of operation. A laboratory may develop its own performance criteria (as QC acceptance criteria), provided such criteria are as or more restrictive than the criteria in this method.


8.1.1 The laboratory must make an initial demonstration of capability (DOC) to generate acceptable precision and recovery with this method. This demonstration is detailed in Section 8.2.


8.1.2 In recognition of advances that are occurring in analytical technology, and to overcome matrix interferences, the laboratory is permitted certain options (section 1.6 and 40 CFR 136.6(b)) to improve separations or lower the costs of measurements. These options may include alternate extraction, concentration, and cleanup procedures (e.g., solid-phase extraction; rotary-evaporator concentration; column chromatography cleanup), changes in column and type of mass spectrometer (40 CFR 136.6(b)(4)(xvi)). Alternate determinative techniques, such as substitution of spectroscopic or immunoassay techniques, and changes that degrade method performance, are not allowed. If an analytical technique other than GC/MS is used, that technique must have a specificity equal to or greater than the specificity of GC/MS for the analytes of interest. The laboratory is also encouraged to participate in inter-comparison and performance evaluation studies (see section 8.10).


8.1.2.1 Each time a modification is made to this method, the laboratory is required to repeat the procedure in section 8.2. If the detection limit of the method will be affected by the change, the laboratory must demonstrate that the MDLs (40 CFR part 136, appendix B) are lower than one-third the regulatory compliance limit or the MDLs in this method, whichever are greater. If calibration will be affected by the change, the instrument must be recalibrated per section 7. Once the modification is demonstrated to produce results equivalent or superior to results produced by this method, that modification may be used routinely thereafter, so long as the other requirements in this method are met (e.g., matrix spike/matrix spike duplicate recovery and relative percent difference).


8.1.2.1.1 If SPE, or another allowed method modification, is to be applied to a specific discharge, the laboratory must prepare and analyze matrix spike/matrix spike duplicate (MS/MSD) samples (section 8.3) and LCS samples (section 8.4). The laboratory must include surrogates (section 8.7) in each of the samples. The MS/MSD and LCS samples must be fortified with the analytes of interest (Section 1.3). If the modification is for nationwide use, MS/MSD samples must be prepared from a minimum of nine different discharges (See section 8.1.2.1.2), and all QC acceptance criteria in this method must be met. This evaluation only needs to be performed once other than for the routine QC required by this method (for example it could be performed by the vendor of the SPE materials) but any laboratory using that specific material must have the results of the study available. This includes a full data package with the raw data that will allow an independent reviewer to verify each determination and calculation performed by the laboratory (see section 8.1.2.2.5, items (a)-(q)).


8.1.2.1.2 Sample matrices on which MS/MSD tests must be performed for nationwide use of an allowed modification:


(a) Effluent from a POTW.


(b) ASTM D5905 Standard Specification for Substitute Wastewater.


(c) Sewage sludge, if sewage sludge will be in the permit.


(d) ASTM D1141 Standard Specification for Substitute Ocean Water, if ocean water will be in the permit.


(e) Untreated and treated wastewaters up to a total of nine matrix types (see https://www.epa.gov/eg/industrial-effluent-guidelines for a list of industrial categories with existing effluent guidelines).


(i) At least one of the above wastewater matrix types must have at least one of the following characteristics:


(A) Total suspended solids greater than 40 mg/L.


(B) Total dissolved solids greater than 100 mg/L.


(C) Oil and grease greater than 20 mg/L.


(D) NaCl greater than 120 mg/L.


(E) CaCO3 greater than 140 mg/L.


(ii) Results of MS/MSD tests must meet QC acceptance criteria in Section 8.3.


(f) A proficiency testing (PT) sample from a recognized provider, in addition to tests of the nine matrices (section 8.1.2.1.1).


8.1.2.2 The laboratory is required to maintain records of modifications made to this method. These records include the following, at a minimum:


8.1.2.2.1 The names, titles, and business street addresses, telephone numbers, and email addresses, of the analyst(s) that performed the analyses and modification, and of the quality control officer that witnessed and will verify the analyses and modifications.


8.1.2.2.2 A list of analytes, by name and CAS Registry Number.


8.1.2.2.3 A narrative stating reason(s) for the modifications.


8.1.2.2.4 Results from all quality control (QC) tests comparing the modified method to this method, including:


(a) Calibration (section 7).


(b) Calibration verification (section 7).


(c) Initial demonstration of capability (section 8.2).


(d) Analysis of blanks (section 8.5).


(e) Matrix spike/matrix spike duplicate analysis (section 8.3).


(f) Laboratory control sample analysis (section 8.4).


8.1.2.2.5 Data that will allow an independent reviewer to validate each determination by tracing the instrument output (peak height, area, or other signal) to the final result. These data are to include:


(a) Sample numbers and other identifiers.


(b) Extraction dates.


(c) Analysis dates and times.


(d) Analysis sequence/run chronology.


(e) Sample weight or volume (ssection 10).


(f) Extract volume prior to each cleanup step (sections 10 and 11).


(g) Extract volume after each cleanup step (section 11).


(h) Final extract volume prior to injection (sections 10 and 12).


(i) Injection volume (section 12.2.3).


(j) Sample or extract dilution (section 12.2.3.2).


(k) Instrument and operating conditions.


(l) Column (dimensions, material, etc).


(m) Operating conditions (temperature program, flow rate, etc).


(n) Detector (type, operating conditions, etc).


(o) Chromatograms, mass spectra, and other recordings of raw data.


(p) Quantitation reports, data system outputs, and other data to link the raw data to the results reported.


(q) A written Standard Operating Procedure (SOP).


8.1.2.2.6 Each individual laboratory wishing to use a given modification must perform the start-up tests in section 8.1.2 (e.g., DOC, MDL), with the modification as an integral part of this method prior to applying the modification to specific discharges. Results of the DOC must meet the QC acceptance criteria in Table 6 for the analytes of interest (section 1.3), and the MDLs must be equal to or lower than the MDLs in Tables 1, 2, or 3 for the analytes of interest.


8.1.3 Before analyzing samples, the laboratory must analyze a blank to demonstrate that interferences from the analytical system, labware, and reagents, are under control. Each time a batch of samples is extracted or reagents are changed, a blank must be extracted and analyzed as a safeguard against laboratory contamination. Requirements for the blank are given in section 8.5.


8.1.4 The laboratory must, on an ongoing basis, spike and analyze to monitor and evaluate method and laboratory performance on the sample matrix. The procedure for spiking and analysis is given in section 8.3.


8.1.5 The laboratory must, on an ongoing basis, demonstrate through analysis of a quality control check sample (laboratory control sample, LCS; on-going precision and recovery sample, OPR) that the measurement system is in control. This procedure is given in section 8.4.


8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is given in section 8.9.


8.1.7 The large number of analytes tested in performance tests in this method present a substantial probability that one or more will fail acceptance criteria when many analytes are tested simultaneously, and a re-test is allowed if this situation should occur. If, however, continued re-testing results in further repeated failures, the laboratory must document and report the failures (e.g., as qualifiers on results), unless the failures are not required to be reported as determined by the regulatory/control authority. Results associated with a QC failure for an analyte regulated in a discharge cannot be used to demonstrate regulatory compliance. QC failures do not relieve a discharger or permittee of reporting timely results.


8.2 Initial demonstration of capability (DOC)—To establish the ability to generate acceptable recovery and precision, the laboratory must perform the DOC in sections 8.2.1 through 8.2.6 for the analytes of interest. The laboratory must also establish MDLs for the analytes of interest using the MDL procedure at 40 CFR part 136, appendix B. The laboratory’s MDLs must be equal to or lower than those listed in Tables 1, 2, or 3 or lower than one third the regulatory compliance limit, whichever is greater. For MDLs not listed in Tables 4 and 5, the laboratory must determine the MDLs using the MDL procedure at 40 CFR part 136, appendix B under the same conditions used to determine the MDLs for the analytes listed in Tables 1, 2, and 3. All procedures used in the analysis, including cleanup procedures, must be included in the DOC.


8.2.1 For the DOC, a QC check sample concentrate (LCS concentrate) containing each analyte of interest (section 1.3) is prepared in a water-miscible solvent. The QC check sample concentrate must be prepared independently from those used for calibration, but may be from the same source as the second-source standard used for calibration verification (Section 7.3). The concentrate should produce concentrations of the analytes of interest in water at the mid-point of the calibration range, and may be at the same concentration as the LCS (section 8.4). Multiple solutions may be required.



Note:

QC check sample concentrates are no longer available from EPA.


8.2.2 Using a pipet or micro-syringe, prepare four LCSs by adding an appropriate volume of the concentrate to each of four aliquots of reagent water, and mix well. The volume of reagent water must be the same as the volume that will be used for the sample, blank (section 8.5), and MS/MSD (section 8.3). A volume of 1-L and a concentration of 100 µg/L were used to develop the QC acceptance criteria in Table 6. Also add an aliquot of the surrogate spiking solution (section 6.8) to the reagent-water aliquots.


8.2.3 Extract and analyze the four LCSs according to the method beginning in Section 10.


8.2.4 Calculate the average percent recovery (X) and the standard deviation of the percent recovery (s) for each analyte using the four results.


8.2.5 For each analyte, compare s and (X) with the corresponding acceptance criteria for precision and recovery in Table 6. For analytes in Table 3 not listed in Table 6, DOC QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 12 and 13). Alternatively, acceptance criteria for analytes not listed in Table 6 may be based on laboratory control charts. If s and (X) for all analytes of interest meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may begin. If any individual s exceeds the precision limit or any individual (X) falls outside the range for recovery, system performance is unacceptable for that analyte.



Note:

The large number of analytes in Tables 1-3 present a substantial probability that one or more will fail at least one of the acceptance criteria when many or all analytes are determined simultaneously. Therefore, the analyst is permitted to conduct a “re-test” as described in section 8.2.6.


8.2.6 When one or more of the analytes tested fail at least one of the acceptance criteria, repeat the test for only the analytes that failed. If results for these analytes pass, system performance is acceptable and analysis of samples and blanks may proceed. If one or more of the analytes again fail, system performance is unacceptable for the analytes that failed the acceptance criteria. Correct the problem and repeat the test (section 8.2). See section 8.1.7 for disposition of repeated failures.



Note:

To maintain the validity of the test and re-test, system maintenance and/or adjustment is not permitted between this pair of tests.


8.3 Matrix spike and matrix spike duplicate (MS/MSD)—The purpose of the MS/MSD requirement is to provide data that demonstrate the effectiveness of the method as applied to the samples in question by a given laboratory, and both the data user (discharger, permittee, regulated entity, regulatory/control authority, customer, other) and the laboratory share responsibility for provision of such data. The data user should identify the sample and the analytes of interest (section 1.3) to be spiked and provide sufficient sample volume to perform MS/MSD analyses. The laboratory must, on an ongoing basis, spike at least 5% of the samples in duplicate from each discharge being monitored to assess accuracy (recovery and precision). If direction cannot be obtained from the data user, the laboratory must spike at least one sample in duplicate per extraction batch of up to 20 samples with the analytes in Table 1. Spiked sample results should be reported only to the data user whose sample was spiked, or as requested or required by a regulatory/control authority, or in a permit.


8.3.1 If, as in compliance monitoring, the concentration of a specific analyte will be checked against a regulatory concentration limit, the concentration of the spike should be at that limit; otherwise, the concentration of the spike should be one to five times higher than the background concentration determined in section 8.3.2, at or near the midpoint of the calibration range, or at the concentration in the LCS (section 8.4) whichever concentration would be larger.


8.3.2 Analyze one sample aliquot to determine the background concentration (B) of the each analyte of interest. If necessary, prepare a new check sample concentrate (section 8.2.1) appropriate for the background concentration. Spike and analyze two additional sample aliquots, and determine the concentration after spiking (A1 and A2) of each analyte. Calculate the percent recoveries (P1 and P2) as 100 (A1 − B)/T and 100 (A2 − B)/T, where T is the known true value of the spike. Also calculate the relative percent difference (RPD) between the concentrations (A1 and A2) as 200 |A1 − A2|/(A1 + A2). If necessary, adjust the concentrations used to calculate the RPD to account for differences in the volumes of the spiked aliquots.


8.3.3 Compare the percent recoveries (P1 and P2) and the RPD for each analyte in the MS/MSD aliquots with the corresponding QC acceptance criteria in Table 6. A laboratory may develop and apply QC acceptance criteria more restrictive than the criteria in Table 6, if desired.


8.3.3.1 If any individual P falls outside the designated range for recovery in either aliquot, or the RPD limit is exceeded, the result for the analyte in the unspiked sample is suspect. See Section 8.1.7 for disposition of failures.


8.3.3.2 The acceptance criteria in Table 6 were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the spike to background ratio approaches 5:1 (Reference 14) and is applied to spike concentrations of 100 µg/L and higher. If spiking is performed at a concentration lower than 100 µg/L, the laboratory must use the QC acceptance criteria in Table 6, the optional QC acceptance criteria calculated for the specific spike concentration in Table 7, or optional in-house criteria (section 8.3.4). To use the acceptance criteria in Table 7: (1) Calculate recovery (X′) using the equation in Table 7, substituting the spike concentration (T) for C; (2) Calculate overall precision (S′) using the equation in Table 7, substituting X′ for X; (3) Calculate the range for recovery at the spike concentration as (100 X′/T) ± 2.44(100 S′/T)% (Reference 14). For analytes in Table 3 not listed in Table 6, QC acceptance criteria must be developed by the laboratory. EPA has provided guidance for development of QC acceptance criteria (References 12 and 13). Alternatively, acceptance criteria may be based on laboratory control charts.


8.3.4 After analysis of a minimum of 20 MS/MSD samples for each target analyte and surrogate, and if the laboratory chooses to develop and apply the optional in-house QC limits (Section 8.3.3), the laboratory should calculate and apply the optional in-house QC limits for recovery and RPD of future MS/MSD samples (Section 8.3). The QC limits for recovery are calculated as the mean observed recovery ±3 standard deviations, and the upper QC limit for RPD is calculated as the mean RPD plus 3 standard deviations of the RPDs. The in-house QC limits must be updated at least every two years and re-established after any major change in the analytical instrumentation or process. If in-house QC limits are developed, at least 80% of the analytes tested in the MS/MSD must have in-house QC acceptance criteria that are tighter than those in Table 6, and the remaining analytes (those other than the analytes included in the 80%) must meet the acceptance criteria in Table 6. If an in-house QC limit for the RPD is greater than the limit in Table 6, then the limit in Table 6 must be used. Similarly, if an in-house lower limit for recovery is below the lower limit in Table 6, then the lower limit in Table 6 must be used, and if an in-house upper limit for recovery is above the upper limit in Table 6, then the upper limit in Table 6 must be used.


8.4 Laboratory control sample (LCS)—A QC check sample (laboratory control sample, LCS; on-going precision and recovery sample, OPR) containing each analyte of interest (Section 1.3) and surrogate must be prepared and analyzed with each extraction batch of up to 20 samples to demonstrate acceptable recovery of the analytes of interest from a clean sample matrix.


8.4.1 Prepare the LCS by adding QC check sample concentrate (section 8.2.1) to reagent water. Include all analytes of interest (section 1.3) in the LCS. The LCS may be the same sample prepared for the DOC (section 8.2.1). The volume of reagent water must be the same as the volume used for the sample, blank (section 8.5), and MS/MSD (Section 8.3). Also add an aliquot of the surrogate spiking solution (section 6.8). The concentration of the analytes in reagent water should be the same as the concentration in the DOC (section 8.2.2).


8.4.2 Analyze the LCS prior to analysis of field samples in the extraction batch. Determine the concentration (A) of each analyte. Calculate the percent recovery (PS) as 100 (A/T)%, where T is the true value of the concentration in the LCS.


8.4.3 Compare the percent recovery (PS) for each analyte with its corresponding QC acceptance criterion in Table 6. For analytes of interest in Table 3 not listed in Table 6, use the QC acceptance criteria developed for the LCS (section 8.4.5), or limits based on laboratory control charts. If the recoveries for all analytes of interest fall within their respective QC acceptance criteria, analysis of blanks and field samples may proceed. If any individual PS falls outside the range, proceed according to section 8.4.4.



Note:

The large number of analytes in Tables 1-3 present a substantial probability that one or more will fail the acceptance criteria when all analytes are tested simultaneously. Because a re-test is allowed in event of failure (sections 8.1.7 and 8.4.3), it may be prudent to extract and analyze two LCSs together and evaluate results of the second analysis against the QC acceptance criteria only if an analyte fails the first test.


8.4.4 Repeat the test only for those analytes that failed to meet the acceptance criteria (PS). If these analytes now pass, system performance is acceptable and analysis of blanks and samples may proceed. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, repeat the test using a fresh LCS (section 8.2.2) or an LCS prepared with a fresh QC check sample concentrate (section 8.2.1), or perform and document system repair. Subsequent to analysis of the LCS prepared with a fresh sample concentrate, or to system repair, repeat the LCS test (section 8.4). If failure of the LCS indicates a systemic problem with samples in the batch, re-extract and re-analyze the samples in the batch. See section 8.1.7 for disposition of repeated failures.



Note:

To maintain the validity of the test and re-test, system maintenance and/or adjustment is not permitted between the pair of tests.


8.4.5 After analysis of 20 LCS samples, and if the laboratory chooses to develop and apply in-house QC limits, the laboratory should calculate and apply in-house QC limits for recovery to future LCS samples (section 8.4). Limits for recovery in the LCS should be calculated as the mean recovery ±3 standard deviations. A minimum of 80% of the analytes tested for in the LCS must have QC acceptance criteria tighter than those in Table 6, and the remaining analytes (those other than the analytes included in the 80%) must meet the acceptance criteria in Table 6. If an in-house lower limit for recovery is lower than the lower limit in Table 6, the lower limit in Table 6 must be used, and if an in-house upper limit for recovery is higher than the upper limit in Table 6, the upper limit in Table 6 must be used. Many of the analytes and surrogates do not contain acceptance criteria. The laboratory should use 60-140% as interim acceptance criteria for recoveries of spiked analytes and surrogates that do not have recovery limits specified in Table 8, and at least 80% of the surrogates must meet the 60-140% interim criteria until in-house LCS and surrogate limits are developed. Alternatively, acceptance criteria for analytes that do not have recovery limits in Table 6 may be based on laboratory control charts. In-house QC acceptance criteria must be updated at least every two years.


8.5 Blank—A blank must be extracted and analyzed with each extraction batch to demonstrate that the reagents and equipment used for preparation and analysis are free from contamination.


8.5.1 Spike the surrogates into the blank. Extract and concentrate the blank using the same procedures and reagents used for the samples, LCS, and MS/MSD in the batch. Analyze the blank immediately after analysis of the LCS (section 8.4) and prior to analysis of the MS/MSD and samples to demonstrate freedom from contamination.


8.5.2 If an analyte of interest is found in the blank: At a concentration greater than the MDL for the analyte, at a concentration greater than one-third the regulatory compliance limit, or at a concentration greater than one-tenth the concentration in a sample in the extraction batch, whichever is greater, analysis of samples must be halted, and the problem corrected. If the contamination is traceable to the extraction batch, samples affected by the blank must be re-extracted and the extracts re-analyzed. If, however, continued re-testing results in repeated blank contamination, the laboratory must document and report the failures (e.g., as qualifiers on results), unless the failures are not required to be reported as determined by the regulatory/control authority. Results associated with blank contamination for an analyte regulated in a discharge cannot be used to demonstrate regulatory compliance. QC failures do not relieve a discharger or permittee of reporting timely results.


8.6 Internal standards responses.


8.6.1 Calibration verification—The responses (GC peak heights or areas) of the internal standards in the calibration verification must be within 50% to 200% (1/2 to 2x) of their respective responses in the mid-point calibration standard. If they are not, repeat the calibration verification (Section 7.4) test or perform and document system repair. Subsequent to repair, repeat the calibration verification. If the responses are still not within 50% to 200%, re-calibrate the instrument (Section 7) and repeat the calibration verification test.


8.6.2 Samples, blanks, LCSs, and MS/MSDs—The responses (GC peak heights or areas) of each internal standard in each sample, blank, and MS/MSD must be within 50% to 200% (1/2 to 2x) of its respective response in the LCS for the extraction batch. If, as a group, all internal standards are not within this range, perform and document system repair, repeat the calibration verification (section 8.4), and re-analyze the affected samples. If a single internal standard is not within the 50% to 200% range, use an alternate internal standard for quantitation of the analyte referenced to the affected internal standard. It may be necessary to use the data system to calculate a new response factor from calibration data for the alternate internal standard/analyte pair. If an internal standard fails the 50-200% criteria and no analytes are detected in the sample, ignore the failure or report it if required by the regulatory/control authority.


8.7 Surrogate recoveries—The laboratory must evaluate surrogate recovery data in each sample against its in-house surrogate recovery limits. The laboratory may use 60-140% as interim acceptance criteria for recoveries for surrogates not listed in Table 8. At least 80% of the surrogates must meet the 60-140% interim criteria until in-house limits are developed. Alternatively, surrogate recovery limits may be developed from laboratory control charts, but such limits must be at least as restrictive as those in Table 8. Spike the surrogates into all samples, blanks, LCSs, and MS/MSDs. Compare surrogate recoveries against the QC acceptance criteria in Table 8 and/or those developed in section 7.3.3 or 8.4.5. If any recovery fails its criteria, attempt to find and correct the cause of the failure. See section 8.1.7 for disposition of failures.


8.8 DDT and endrin decomposition (breakdown)—If DDT and/or endrin are to be analyzed using this method, the DDT/endrin decomposition test in section 13.8 must be performed to reliably quantify these two pesticides.


8.9 As part of the QC program for the laboratory, control charts or statements of accuracy for wastewater samples must be assessed and records maintained (40 CFR 136.7(c)(1)(viii)). After analysis of five or more spiked wastewater samples as in section 8.3, calculate the average percent recovery (PX) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent interval from PX −2sp to PX +2sp. For example, if PX = 90% and sp = 10%, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each analyte on a regular basis (e.g., after each 5-10 new accuracy measurements). If desired, statements of accuracy for laboratory performance, independent of performance on samples, may be developed using LCSs.


8.10 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of environmental measurements. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.


9. Sample Collection, Preservation, and Handling

9.1 Collect samples as grab samples in amber or clear glass bottles, or in refrigerated bottles using automatic sampling equipment. If clear glass is used, protect samples from light. Collect 1-L of ambient waters, effluents, and other aqueous samples. If the sensitivity of the analytical system is sufficient, a smaller volume (e.g., 250 mL), but no less than 100 mL, may be used. Conventional sampling practices (Reference 15) should be followed, except that the bottle must not be pre-rinsed with sample before collection. Automatic sampling equipment must be as free as possible of polyvinyl chloride or other tubing or other potential sources of contamination. If needed, collect additional sample(s) for the MS/MSD (section 8.3).


9.2 Ice or refrigerate samples at ≤6 °C from the time of collection until extraction, but do not freeze. If residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. Any method suitable for field use may be employed to test for residual chlorine (Reference 16). Add more sodium sulfate if 80 mg/L is insufficient but do not add excess sodium thiosulfate. If sodium thiosulfate interferes in the determination of the analytes, an alternate preservative (e.g., ascorbic acid or sodium sulfite) may be used. If preservative has been added, shake the sample vigorously for one minute. Maintain the hermetic seal on the sample bottle until time of analysis.


9.3 All samples must be extracted within 7 days of collection and sample extracts must be analyzed within 40 days of extraction.


10. Extraction

10.1 This section contains procedures for separatory funnel liquid-liquid extraction (SFLLE) and continuous liquid-liquid extraction (CLLE). SFLLE is faster, but may not be as effective as CLLE for recovery of polar analytes such as phenol. SFLLE is labor intensive and may result in formation of emulsions that are difficult to break. CLLE is less labor intensive, avoids emulsion formation, but requires more time (18-24 hours) and more hood space, and may require more solvent. The procedures assume base-neutral extraction followed by acid extraction. For some matrices and analytes of interest, improved results may be obtained by acid-neutral extraction followed by base extraction. A single acid or base extraction may also be performed. If an extraction scheme alternate to base-neutral followed by acid extraction is used, all QC tests must be performed and all QC acceptance criteria must be met with that extraction scheme as an integral part of this method. Solid-phase extraction (SPE) may be used provided requirements in section 8.1.2 are met.


10.2 Separatory funnel liquid-liquid extraction (SFLLE) and extract concentration.


10.2.1 The SFLLE procedure below assumes a sample volume of 1 L. When a different sample volume is extracted, adjust the volume of methylene chloride accordingly.


10.2.2 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into the separatory funnel. Pipet the surrogate standard spiking solution (section 6.8) into the separatory funnel. If the sample will be used for the LCS or MS or MSD, pipet the appropriate check sample concentrate (section 8.2.1 or 8.3.2) into the separatory funnel. Mix well. Check the pH of the sample with wide-range pH paper and adjust to pH 11-13 with sodium hydroxide solution.


10.2.3 Add 60 mL of methylene chloride to the sample bottle, seal, and shake for approximately 30 seconds to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for two minutes with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 minutes. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool or phase-separation paper, salting, centrifugation, or other physical methods. Collect the methylene chloride extract in a flask. If the emulsion cannot be broken (recovery of

10.2.4 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.


10.2.5 Adjust the pH of the aqueous phase to less than 2 using sulfuric acid. Serially extract the acidified aqueous phase three times with 60 mL aliquots of methylene chloride. Collect and combine the extracts in a flask in the same manner as the base/neutral extracts.



Note:

Base/neutral and acid extracts may be combined for concentration and analysis provided all QC tests are performed and all QC acceptance criteria met for the analytes of interest with the combined extract as an integral part of this method, and provided that the analytes of interest are as reliably identified and quantified as when the extracts are analyzed separately. If doubt exists as to whether identification and quantitation will be affected by use of a combined extract, the fractions must be analyzed separately.


10.2.6 For each fraction or the combined fractions, assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator so long as the requirements in section 8.2 are met.


10.2.7 For each fraction or the combined fractions, pour the extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20-30 mL of methylene chloride to complete the quantitative transfer.


10.2.8 Add one or two clean boiling chips and attach a three-ball Snyder column to the evaporative flask for each fraction (section 10.2.7). Pre-wet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60-65 °C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15-20 minutes. At the proper rate of distillation, the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL or other determined amount, remove the K-D apparatus from the water bath and allow to drain and cool for at least 10 minutes. Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1-2 mL of methylene chloride. A 5-mL syringe is recommended for this operation. If the sample will be cleaned up, reserve the K-D apparatus for concentration of the cleaned up extract. Adjust the volume to 5 mL with methylene chloride and proceed to section 11 for cleanup; otherwise, further concentrate the extract for GC/MS analysis per section 10.2.9 or 10.2.10.


10.2.9 Micro Kuderna-Danish concentration—Add another one or two clean boiling chips to the concentrator tube for each fraction and attach a two-ball micro-Snyder column. Pre-wet the Snyder column by adding about 0.5 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60-65 °C) so that the concentrator tube is partially immersed in hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5-10 minutes. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches about 1 mL or other determined amount, remove the K-D apparatus from the water bath and allow it to drain and cool for at least 10 minutes. Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with approximately 0.2 mL of or methylene chloride. Adjust the final volume to 1.0 mL or a volume appropriate to the sensitivity desired (e.g., to meet lower MDLs or for selected ion monitoring). Record the volume, stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extracts will be stored longer than two days, they should be transferred to fluoropolymer-lined screw-cap vials and labeled base/neutral or acid fraction as appropriate. Mark the level of the extract on the vial so that solvent loss can be detected.


10.2.10 Nitrogen evaporation and solvent exchange—Extracts may be concentrated for analysis using nitrogen evaporation in place of micro K-D concentration (section 10.2.9). Extracts that have been cleaned up using sulfur removal (section 11.2) and are ready for analysis are exchanged into methylene chloride.


10.2.10.1 Transfer the vial containing the sample extract to the nitrogen evaporation (blowdown) device (section 5.8). Lower the vial into the water bath and begin concentrating. If the more volatile analytes (section 1.2) are to be concentrated, use room temperature for concentration; otherwise, a slightly elevated (e.g., 30-45 °C) may be used. During the solvent evaporation process, keep the solvent level below the water level of the bath and do not allow the extract to become dry. Adjust the flow of nitrogen so that the surface of the solvent is just visibly disturbed. A large vortex in the solvent may cause analyte loss.


10.2.10.2 Extracts to be solvent exchanged—When the volume of the liquid is approximately 200 µL, add 2 to 3 mL of methylene chloride and continue concentrating to approximately 100 µL. Repeat the addition of solvent and concentrate once more. Adjust the final extract volume to be consistent with the volume extracted and the sensitivity desired.


10.2.10.3 For extracts that have been cleaned up by GPC and that are to be concentrated to a nominal volume of 1 mL, adjust the final volume to compensate the GPC loss. For a 50% GPC loss, concentrate the extract to 1/2000 of the volume extracted. For example, if the volume extracted is 950 mL, adjust the final volume to 0.48 mL. For extracts that have not been cleaned up by GPC and are to be concentrated to a nominal volume of 1.0 mL, adjust the final extract volume to 1/1000 of the volume extracted. For example, if the volume extracted is 950 mL, adjust the final extract volume to 0.95 mL. Alternative means of compensating the loss during GPC are acceptable so long as they produce results as accurate as results produced using the procedure detailed in this Section. An alternative final volume may be used, if desired, and the calculations adjusted accordingly.



Note:

The difference in the volume fraction for an extract cleaned up by GPC accounts for the loss in GPC cleanup. Also, by preserving the ratio between the volume extracted and the final extract volume, the concentrations and detection limits do not need to be adjusted for differences in the volume extracted and the extract volume.


10.2.11 Transfer the concentrated extract to a vial with fluoropolymer-lined cap. Seal the vial and label with the sample number. Store in the dark at room temperature until ready for GC analysis. If GC analysis will not be performed on the same day, store the vial in the dark at ≤6 °C. Analyze the extract by GC/MS per the procedure in section 12.


10.2.12 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to an appropriately sized graduated cylinder. For sample volumes on the order of 1000 mL, record the sample volume to the nearest 10 mL; for sample volumes on the order of 100 mL, record the volume to the nearest 1 mL. Sample volumes may also be determined by weighing the container before and after filling to the mark with water.


10.3 Continuous liquid/liquid extraction (CLLE).



Note:

With CLLE, phenol, 2,4-dimethyl phenol, and some other analytes may be preferentially extracted into the base-neutral fraction. Determine an analyte in the fraction in which it is identified and quantified most reliably. Also, the short-chain phthalate esters (e.g., dimethyl phthalate, diethyl phthalate) and some other compounds may hydrolyze during prolonged exposure to basic conditions required for continuous extraction, resulting in low recovery of these analytes. When these analytes are of interest, their recovery may be improved by performing the acid extraction first.


10.3.1 Use CLLE when experience with a sample from a given source indicates an emulsion problem, or when an emulsion is encountered during SFLLE. CLLE may be used for all samples, if desired.


10.3.2 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Check the pH of the sample with wide-range pH paper and adjust to pH 11-13 with sodium hydroxide solution. Transfer the sample to the continuous extractor. Pipet surrogate standard spiking solution (section 6.8) into the sample. If the sample will be used for the LCS or MS or MSD, pipet the appropriate check sample concentrate (section 8.2.1 or 8.3.2) into the extractor. Mix well. Add 60 mL of methylene chloride to the sample bottle, seal, and shake for 30 seconds to rinse the inner surface. Transfer the solvent to the extractor.


10.3.3 Repeat the sample bottle rinse with an additional 50-100 mL portion of methylene chloride and add the rinse to the extractor.


10.3.4 Add a suitable volume of methylene chloride to the distilling flask (generally 200-500 mL), add sufficient reagent water to ensure proper operation, and extract for 18-24 hours. A shorter or longer extraction time may be used if all QC acceptance criteria are met. Test and, if necessary, adjust the pH of the water during the second or third hour of the extraction. After extraction, allow the apparatus to cool, then detach the distilling flask. Dry, concentrate, and seal the extract per sections 10.2.6 through 10.2.11. See the note at section 10.2.5 regarding combining extracts of the base/neutral and acid fractions.


10.3.5 Charge the distilling flask with methylene chloride and attach it to the continuous extractor. Carefully, while stirring, adjust the pH of the aqueous phase to less than 2 using sulfuric acid. Extract for 18-24 hours. A shorter or longer extraction time may be used if all QC acceptance criteria are met. Test and, if necessary, adjust the pH of the water during the second or third hour of the extraction. After extraction, allow the apparatus to cool, then detach the distilling flask. Dry, concentrate, and seal the extract per sections 10.2.6 through 10.2.11. Determine the sample volume per section 10.2.12.


11. Extract Cleanup


Note:

Cleanup may not be necessary for relatively clean samples (e.g., treated effluents, groundwater, drinking water). If particular circumstances require the use of a cleanup procedure, the laboratory may use any or all of the procedures below or any other appropriate procedure. Before using a cleanup procedure, the laboratory must demonstrate that the requirements of section 8.1.2 can be met using the cleanup procedure as an integral part of this method.


11.1 Gel permeation chromatography (GPC).


11.1.1 Calibration.


11.1.1.1 Load the calibration solution (section 6.12) into the sample loop.


11.1.1.2 Inject the calibration solution and record the signal from the detector. The elution pattern will be corn oil, bis(2-ethylhexyl) phthalate, pentachlorophenol, perylene, and sulfur.


11.1.1.3 Set the “dump time” to allow >85% removal of the corn oil and >85% collection of the phthalate.


11.1.1.4 Set the “collect time” to the peak minimum between perylene and sulfur.


11.1.1.5 Verify calibration with the calibration solution after every 20 or fewer extracts. Calibration is verified if the recovery of the pentachlorophenol is greater than 85%. If calibration is not verified, recalibrate using the calibration solution, and re-extract and clean up the preceding extracts using the calibrated GPC system.


11.1.2 Extract cleanup—GPC requires that the column not be overloaded. The column specified in this method is designed to handle a maximum of 0.5 g of high molecular weight material in a 5-mL extract. If the extract is known or expected to contain more than 0.5 g, the extract is split into fractions for GPC and the fractions are combined after elution from the column. The solids content of the extract may be obtained gravimetrically by evaporating the solvent from a 50-µL aliquot.


11.1.2.1 Filter the extract or load through the filter holder to remove particulates. Load the extract into the sample loop. The maximum capacity of the column is 0.5-1.0 g. If necessary, split the extract into multiple aliquots to prevent column overload.


11.1.2.2 Elute the extract using the calibration data determined in Section 11.1.1. Collect the eluate in the K-D apparatus reserved in section 10.2.8.


11.1.3 Concentrate the cleaned up extract per sections 10.2.8 and 10.2.9 or 10.2.10.


11.1.4 Rinse the sample loading tube thoroughly with methylene chloride between extracts to prepare for the next sample.


11.1.5 If a particularly dirty extract is encountered, run a methylene chloride blank through the system to check for carry-over.


11.2 Sulfur removal.



Note:

Separate procedures using copper or TBA sulfite are provided in this section for sulfur removal. They may be used separately or in combination, if desired.


11.2.1 Removal with copper (Reference 17).



Note:

If an additional compound (Table 3) is to be determined; sulfur is to be removed; copper will be used for sulfur removal; and a sulfur matrix is known or suspected to be present, the laboratory must demonstrate that the additional compound can be successfully extracted and treated with copper in the sulfur matrix. Some of the additional compounds (Table 3) are known not to be amenable to sulfur removal with copper (e.g., Atrazine and Diazinon).


11.2.1.1 Quantitatively transfer the extract from section 10.2.8 to a 40- to 50-mL flask or bottle. If there is evidence of water in the concentrator tube after the transfer, rinse the tube with small portions of hexane:acetone (40:60) and add to the flask or bottle. Mark and set aside the concentrator tube for use in re-concentrating the extract.


11.2.1.2 Add 10-20 g of granular anhydrous sodium sulfate to the flask. Swirl to dry the extract.


11.2.1.3 Add activated copper (section 6.13.1.4) and allow to stand for 30—60 minutes, swirling occasionally. If the copper does not remain bright, add more and swirl occasionally for another 30-60 minutes.


11.2.1.4 After drying and sulfur removal, quantitatively transfer the extract to a nitrogen-evaporation vial or tube and proceed to section 10.2.10 for nitrogen evaporation and solvent exchange, taking care to leave the sodium sulfate and copper in the flask.


11.2.2 Removal with TBA sulfite.


11.2.2.1 Using small volumes of hexane, quantitatively transfer the extract to a 40- to 50-mL centrifuge tube with fluoropolymer-lined screw cap.


11.2.2.2 Add 1-2 mL of TBA sulfite reagent (section 6.13.2.4), 2-3 mL of 2-propanol, and approximately 0.7 g of sodium sulfite (section 6.13.2.2) crystals to the tube. Cap and shake for 1-2 minutes. If the sample is colorless or if the initial color is unchanged, and if clear crystals (precipitated sodium sulfite) are observed, sufficient sodium sulfite is present. If the precipitated sodium sulfite disappears, add more crystalline sodium sulfite in approximately 0.5 g portions until a solid residue remains after repeated shaking.


11.2.2.3 Add 5-10 mL of reagent water and shake for 1-2 minutes. Centrifuge to settle the solids.


11.2.2.4 Quantitatively transfer the hexane (top) layer through a small funnel containing a few grams of granular anhydrous sodium sulfate to a nitrogen-evaporation vial or tube and proceed to section 10.2.10 for nitrogen evaporation and solvent exchange.


12. Gas Chromatography/Mass Spectrometry

12.1 Establish the operating conditions in Table 4 or 5 for analysis of a base/neutral or acid extract, respectively. For analysis of a combined extract (section 10.2.5, note), use the operating conditions in Table 4 MDLs and MLs for the analytes are given in Tables 1, 2, and 3. Retention times for many of the analytes are given in Tables 4 and 5. Examples of the separations achieved are shown in Figure 2 for the combined extract. Alternative columns or chromatographic conditions may be used if the requirements of section 8.2 are met. Verify system performance per section 13.


12.2 Analysis of a standard or extract.


12.2.1 Bring the standard or concentrated extract (section 10.2.9 or 10.2.11) to room temperature and verify that any precipitate has redissolved. Verify the level on the extract and bring to the mark with solvent if required.


12.2.2 Add the internal standard solution (section 6.9) to the extract. Mix thoroughly.


12.2.3 Inject an appropriate volume of the sample extract or standard solution using split, splitless, solvent purge, large-volume, or on-column injection. If the sample is injected manually the solvent-flush technique should be used. The injection volume depends upon the technique used and the ability to meet MDLs or reporting limits for regulatory compliance. Injected volumes must be the same for standards and sample extracts. Record the volume injected to two significant figures.


12.2.3.1 Start the GC column oven program upon injection. Start MS data collection after the solvent peak elutes. Stop data collection after benzo(ghi)perylene elutes for the base/neutral or combined fractions, or after pentachlorophenol elutes for the acid fraction. Return the column to the initial temperature for analysis of the next standard solution or extract.


12.2.3.2 If the concentration of any analyte of interest exceeds the calibration range, either extract and analyze a smaller sample volume, or dilute and analyze the diluted extract after bringing the concentrations of the internal standards to the levels in the undiluted extract.


12.2.4 Perform all qualitative and quantitative measurements as described in Sections 14 and 15. When standards and extracts are not being used for analyses, store them refrigerated at ≤6 °C protected from light in screw-cap vials equipped with un-pierced fluoropolymer-lined septa.


13. Performance Tests

13.1 At the beginning of each 12-hour shift during which standards or extracts will be analyzed, perform the tests in sections 13.2-13.4 to verify system performance. If an extract is concentrated for greater sensitivity (e.g., by SIM), all tests must be performed at levels consistent with the reduced extract volume.


13.2 DFTPP—Inject the DFTPP standard (section 6.10) and verify that the criteria for DFTPP in section 7.2.1.1 and Table 9A (Reference 18) for a quadrupole MS, or Table 9B (Reference 19) for a time-of-flight MS, are met.


13.3 GC resolution—The resolution should be verified on the mid-point concentration of the initial calibration as well as the laboratory designated continuing calibration verification level if closely eluting isomers are to be reported (e.g., benzo(b)fluoranthene and benzo(k)fluoranthene). Sufficient gas chromatographic resolution is achieved if the height of the valley between two isomer peaks is less than 50% of the average of the two peak heights.


13.4 Calibration verification—Verify calibration per sections 7.3 and Table 6.


13.5 Peak tailing—Verify the tailing factor specifications are met per Section 7.2.1.1.


13.6 Laboratory control sample and blank—Analyze the extracts of the LCS and blank at the beginning of analyses of samples in the extraction batch (section 3.1). The LCS must meet the requirements in section 8.4, and the blank must meet the requirements in section 8.5 before sample extracts may be analyzed.


13.7 Analysis of DFTPP, the DDT/Endrin decomposition test (if used), the LCS, and the blank are outside of the 12-hour analysis shift (section 3.1). The total time for DFTPP, DDT/Endrin, the LCS, the blank, and the 12-hour shift must not exceed 15 hours.


13.8 Decomposition of DDT and endrin—If DDT and/or endrin are to be determined, this test must be performed prior to calibration verification (section 13.4). The QC acceptance criteria (section 13.8.3) must be met before analyzing samples for DDE and/or Endrin. DDT decomposes to DDE and DDD. Endrin decomposes to endrin aldehyde and endrin ketone.


13.8.1 Inject 1 µL of the DDT and endrin decomposition solution (section 6.14). As noted in section 6.14, other injection volumes may be used as long as the concentrations of DDT and endrin in the solution are adjusted to introduce the masses of the two analytes into the instrument that are listed in section 6.14.


13.8.2 Measure the areas of the peaks for DDT, DDE, DDD, Endrin, Endrin aldehyde, and Endrin ketone. Calculate the percent breakdown as shown in the equations below:



13.8.3 Both the % breakdown of DDT and of Endrin must be less than 20%, otherwise the system is not performing acceptably for DDT and endrin. In this case, repair the GC column system that failed and repeat the performance tests (sections 13.2 to 13.6) until the specification is met.



Note:

DDT and endrin decomposition are usually caused by accumulation of particulates in the injector and in the front end of the column. Cleaning and silanizing the injection port liner, and breaking off a short section of the front end of the column will usually eliminate the decomposition problem. Either of these corrective actions may affect retention times, GC resolution, and calibration linearity.


14. Qualitative Identification

14.1 Identification is accomplished by comparison of data from analysis of a sample or blank with data stored in the GC/MS data system (sections 5.6.5 and 7.2.1.2). Identification of an analyte is confirmed per sections 14.1.1 through 14.1.4.


14.1.1 The signals for the quantitation and secondary m/z’s stored in the data system for each analyte of interest must be present and must maximize within the same two consecutive scans.


14.1.2 The retention time for the analyte should be within ± 10 seconds of the analyte in the calibration verification run at the beginning of the shift (section 7.3 or 13.4).



Note:

Retention time windows other than ± 10 seconds may be appropriate depending on the performance of the gas chromatograph or observed retention time drifts due to certain types of matrix effects. Relative retention time (RRT) may be used as an alternative to absolute retention times if retention time drift is a concern. RRT is a unitless quantity (see Sec. 22.2), although some procedures refer to “RRT units” in providing the specification for the agreement between the RRT values in the sample and the calibration verification or other standard. When significant retention time drifts are observed, dilutions or spiked samples may help the analyst determine the effects of the matrix on elution of the target analytes and to assist in qualitative identification.


14.1.3 Either the background corrected EICP areas, or the corrected relative intensities of the mass spectral peaks at the GC peak maximum, must agree within 50% to 200% (1/2 to 2 times) for the quantitation and secondary m/z’s in the reference mass spectrum stored in the data system (section 7.2.1.2), or from a reference library. For example, if a peak has an intensity of 20% relative to the base peak, the analyte is identified if the intensity of the peak in the sample is in the range of 10% to 40% of the base peak. If identification is ambiguous, an experienced spectrometrist (section 1.7) must determine the presence or absence of the compound.


14.2 Structural isomers that produce very similar mass spectra should be identified as individual isomers if they have sufficiently different gas chromatographic retention times. Sufficient gas chromatographic resolution is achieved if the height of the valley between two isomer peaks is less than 50% of the average of the two peak heights. Otherwise, structural isomers are identified as isomeric pairs.


15. Calculations

15.1 When an analyte has been identified, quantitation of that analyte is based on the integrated abundance from the EICP of the primary characteristic m/z in Table 4 or 5. Calculate the concentration in the extract using the response factor (RF) determined in Section 7.2.2 and Equation 2. If the concentration of an analyte exceeds the calibration range, dilute the extract by the minimum amount to bring the concentration into the calibration range, and re-analyze the extract. Determine a dilution factor (DF) from the amount of the dilution. For example, if the extract is diluted by a factor of 2, DF = 2.



where:

Cex = Concentration of the analyte in the extract, in µg/mL, and the other terms are as defined in section 7.2.2.

Calculate the concentration of the analyte in the sample using the concentration in the extract, the extract volume, the sample volume, and the dilution factor, per Equation 3:



where:

Csamp = Concentration of the analyte in the sample

Cex = Concentration of the analyte in the extract, in µg/mL

Vex = Volume of extract (mL)

Vs = Volume of sample (L)

DF = Dilution factor

15.2 Reporting of results. As noted in section 1.4.1, EPA has promulgated this method at 40 CFR part 136 for use in wastewater compliance monitoring under the National Pollutant Discharge Elimination System (NPDES). The data reporting practices described here are focused on such monitoring needs and may not be relevant to other uses of the method.


15.2.1 Report results for wastewater samples in µg/L without correction for recovery. (Other units may be used if required by in a permit.) Report all QC data with the sample results.


15.2.2 Reporting level. Unless specified otherwise by a regulatory authority or in a discharge permit, results for analytes that meet the identification criteria are reported down to the concentration of the ML established by the laboratory through calibration of the instrument (see section 7.3.2 and the glossary for the derivation of the ML). EPA considers the terms “reporting limit,” “quantitation limit,” “limit of quantitation,” and “minimum level” to be synonymous.


15.2.2.1 Report a result for each analyte in each field sample or QC standard at or above the ML to 3 significant figures. Report a result for each analyte found in each field sample or QC standard below the ML as “ML” where ML is the concentration of the analyte at the ML, or as required by the regulatory/control authority or permit. Report a result for each analyte in a blank at or above the MDL to 2 significant figures. Report a result for each analyte found in a blank below the MDL as “MDL,” where MDL is the concentration of the analyte at the MDL, or as required by the regulatory/control authority or permit.


15.2.2.2 In addition to reporting results for samples and blanks separately, the concentration of each analyte in a blank associated with the sample may be subtracted from the result for that sample, but only if requested or required by a regulatory authority or in a permit. In this case, both the sample result and the blank results must be reported together.


15.2.2.3 Report a result for an analyte found in a sample or extract that has been diluted at the least dilute level at which the area at the quantitation m/z is within the calibration range (i.e., above the ML for the analyte) and the MS/MSD recovery and RPD are within their respective QC acceptance criteria (Table 6). This may require reporting results for some analytes from different analyses.


15.2.3 Results from tests performed with an analytical system that is not in control (i.e., that does not meet acceptance criteria for any QC test in this method) must be documented and reported (e.g., as a qualifier on results), unless the failure is not required to be reported as determined by the regulatory/control authority. Results associated with a QC failure cannot be used to demonstrate regulatory compliance. QC failures do not relieve a discharger or permittee of reporting timely results. If the holding time would be exceeded for a re-analysis of the sample, the regulatory/control authority should be consulted for disposition.


16. Method Performance

16.1 The basic version of this method was tested by 15 laboratories using reagent water, drinking water, surface water, and industrial wastewaters spiked at six concentrations over the range 5-1300 µg/L (Reference 2). Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the analyte and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 7.


16.2 As noted in section 1.1, this method was validated through an interlaboratory study in the early 1980s. However, the fundamental chemistry principles used in this method remain sound and continue to apply.


16.3 A chromatogram of the combined acid/base/neutral calibration standard is shown in Figure 2.


17. Pollution Prevention

17.1 Pollution prevention encompasses any technique that reduces or eliminates the quantity or toxicity of waste at the point of generation. Many opportunities for pollution prevention exist in laboratory operations. EPA has established a preferred hierarchy of environmental management techniques that places pollution prevention as the management option of first choice. Whenever feasible, the laboratory should use pollution prevention techniques to address waste generation. When wastes cannot be reduced at the source, the Agency recommends recycling as the next best option.


17.2 The analytes in this method are used in extremely small amounts and pose little threat to the environment when managed properly. Standards should be prepared in volumes consistent with laboratory use to minimize the disposal of excess volumes of expired standards. This method utilizes significant quantities of methylene chloride. Laboratories are encouraged to recover and recycle this and other solvents during extract concentration.


17.3 For information about pollution prevention that may be applied to laboratories and research institutions, consult Less is Better: Laboratory Chemical Management for Waste Reduction, available from the American Chemical Society’s Department of Governmental Relations and Science Policy, 1155 16th Street NW., Washington DC 20036, 202-872-4477.


18. Waste Management

18.1 The laboratory is responsible for complying with all Federal, State, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions, and to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations. An overview of requirements can be found in Environmental Management Guide for Small Laboratories (EPA 233-B-98-001).


18.2 Samples at pH 12, are hazardous and must be handled and disposed of as hazardous waste, or neutralized and disposed of in accordance with all federal, state, and local regulations. It is the laboratory’s responsibility to comply with all federal, state, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions. The laboratory using this method has the responsibility to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations. For further information on waste management, see “The Waste Management Manual for Laboratory Personnel,” also available from the American Chemical Society at the address in section 17.3.


18.3 Many analytes in this method decompose above 500 ºC. Low-level waste such as absorbent paper, tissues, and plastic gloves may be burned in an appropriate incinerator. Gross quantities of neat or highly concentrated solutions of toxic or hazardous chemicals should be packaged securely and disposed of through commercial or governmental channels that are capable of handling these types of wastes.


18.4 For further information on waste management, consult The Waste Management Manual for Laboratory Personnel and Less is Better-Laboratory Chemical Management for Waste Reduction, available from the American Chemical Society’s Department of Government Relations and Science Policy, 1155 16th Street NW., Washington, DC 20036, 202-872-4477.


19. References

1. “Sampling and Analysis Procedures for Screening of Industrial Effluents for Priority Pollutants,” U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1977, Revised April 1977.

2. “EPA Method Study 30, Method 625, Base/Neutrals, Acids, and Pesticides,” EPA 600/4-84-053, National Technical Information Service, PB84-206572, Springfield, Virginia 22161, June 1984.

3. 40 CFR part 136, appendix B.

4. Olynyk, P., Budde, W.L. and Eichelberger, J.W. “Method Detection Limit for Methods 624 and 625,” Unpublished report, May 14, 1980.

5. Annual Book of ASTM Standards, Volume 11.02, D3694-96, “Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,” American Society for Testing and Materials, Philadelphia.

6. Solutions to Analytical Chemistry Problems with Clean Water Act Methods, EPA 821-R-07-002, March 2007.

7. “Carcinogens-Working With Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

8. “OSHA Safety and Health Standards, General Industry,” (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

9. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety, 7th Edition, 2003.

10. Johnson, R.A., and Wichern, D.W., “Applied Multivariate Statistical Analysis,” 3rd edition, Prentice Hall, Englewood Cliffs, NJ, 1992.

11. 40 CFR 136.6(b)(4)(x).

12. 40 CFR 136.6(b)(2)(i).

13. Protocol for EPA Approval of New Methods for Organic and Inorganic Analytes in Wastewater and Drinking Water (EPA-821-B-98-003) March 1999.

14. Provost, L.P. and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in section 8.3.3 is two times the value 1.22 derived in this report.)

15. ASTM Annual Book of Standards, Part 31, D3370-76. “Standard Practices for Sampling Water,” American Society for Testing and Materials, Philadelphia.

16. 40 CFR 136.3(a), Table IB, Chlorine—Total Residual.

17. “Manual of Analytical Methods for the Analysis of Pesticides in Human and Environmental Samples,” EPA-600/8-80-038, U.S. Environmental Protection Agency, Health Effects Research Laboratory, Research Triangle Park, North Carolina.

18. Eichelberger, J.W., Harris, L.E., and Budde, W.L. “Reference Compound to Calibrate Ion Abundance Measurement in Gas Chromatography-Mass Spectrometry,” Analytical Chemistry, 47, 995 (1975).

19. Letter of approval of acceptance criteria for DFTPP for time-of-flight mass spectrometers from William A. Telliard and Herb Brass of EPA to Jack Cochran of LECO Corporation, February 9, 2005.

20. Tables

Table 1—Non Pesticide/PCB Base/Neutral Extractables
1

Analyte
CAS registry
MDL
4

(ug/L)
ML
5

(ug/L)
Acenaphthene83-32-91.95.7
Acenaphthylene208-96-83.510.5
Anthracene120-12-71.95.7
Benzidine
2		92-87-544132
Benzo(a)anthracene56-55-37.823.4
Benzo(a)pyrene50-32-82.57.5
Benzo(b)fluoranthene205-99-24.814.4
Benzo(k)fluoranthene207-08-92.57.5
Benzo(ghi)perylene191-24-24.112.3
Benzyl butyl phthalate85-68-72.57.5
bis(2-Chloroethoxy)methane111-91-15.315.9
bis(2-Ethylhexyl)phthalate117-81-72.57.5
bis(2-Chloroisopropyl) ether (2,2′-Oxybis[1-chloropropane])108-60-15.717.1
4-Bromophenyl phenyl ether101-55-31.95.7
2-Chloronaphthalene91-58-71.95.7
4-Chlorophenyl phenyl ether7005-72-34.212.6
Chrysene218-01-92.57.5
Dibenz(a,h)anthracene53-70-32.57.5
Di-n-butylphthalate84-74-22.57.5
3,3′-Dichlorobenzidine91-94-116.549.5
Diethyl phthalate84-66-21.95.7
Dimethyl phthalate131-11-31.64.8
2,4-Dinitrotoluene121-14-25.717.1
2,6-Dinitrotoluene606-20-21.95.7
Di-n-octylphthalate117-84-02.57.5
Fluoranthene206-44-02.26.6
Fluorene86-73-71.95.7
Hexachlorobenzene118-74-11.95.7
Hexachlorobutadiene87-68-30.92.7
Hexachloroethane67-72-11.64.8
Indeno(1,2,3-cd)pyrene193-39-53.711.1
Isophorone78-59-12.26.6
Naphthalene91-20-31.64.8
Nitrobenzene98-95-31.95.7
N-Nitrosodi-n-propylamine
3		621-64-7——
Phenanthrene85-01-85.416.2
Pyrene129-00-01.95.7
1,2,4-Trichlorobenzene120-82-11.95.7


1 All analytes in this table are Priority Pollutants (40 CFR part 423, appendix A).


2 Included for tailing factor testing.


3 See section 1.2.


4 MDL values from the 1984 promulgated version of Method 625.


5 ML = Minimum Level—see Glossary for definition and derivation.


Table 2—Acid Extractables
1

Analyte
CAS registry
MDL
3

(ug/L)
ML
4

(ug/L)
4-Chloro-3-methylphenol59-50-73.09.0
2-Chlorophenol95-57-83.39.9
2,4-Dichlorophenol120-83-22.78.1
2,4-Dimethylphenol105-67-92.78.1
2,4-Dinitrophenol51-28-542126
2-Methyl-4,6-dinitrophenol534-52-12472
2-Nitrophenol88-75-53.610.8
4-Nitrophenol100-02-72.47.2
Pentachlorophenol
2		87-86-53.610.8
Phenol108-95-21.54.5
2,4,6-Trichlorophenol88-06-22.78.1


1 All analytes in this table are Priority Pollutants (40 CFR part 423, appendix A).


2 See section 1.2; included for tailing factor testing.


3 MDL values from the 1984 promulgated version of Method 625.


4 ML = Minimum Level—see Glossary for definition and derivation.


Table 3—Additional Extractable Analytes
1 2

Analyte
CAS registry
MDL
7

(ug/L)
ML
8

(ug/L)
Acetophenone98-86-2
2-Acetylaminofluorene53-96-3
1-Acetyl-2-thiourea591-08-2
Alachlor15972-60-8
Aldrin
3		309-00-21.95.7
Ametryn834-12-8
2-Aminoanthraquinone117-79-3
Aminoazobenzene60-09-3
4-Aminobiphenyl92-67-1
3-Amino-9-ethylcarbazole132-32-1
Anilazine101-05-3
Aniline62-53-3
o-Anisidine90-04-0
Aramite140-57-8
Atraton1610-17-9
Atrazine1912-24-9
Azinphos-methyl86-50-0
Barban101-27-9
Benzanthrone82-05-3
Benzenethiol108-98-5
Benzoic acid65-85-0
2,3-Benzofluorene243-17-4
p-Benzoquinone106-51-4
Benzyl alcohol100-51-6
alpha-BHC
3 4		319-84-6
beta-BHC
3		319-85-73.19.3
gamma-BHC (Lindane)
3 4		58-89-84.212.6
delta-BHC
3		319-86-8
Biphenyl92-52-4
Bromacil314-40-9
2-Bromochlorobenzene694-80-4
3-Bromochlorobenzene108-39-2
Bromoxynil1689-84-5
Butachlor2318-4669
Butylate2008-41-5
n-C10 (n-decane)124-18-5
n-C12 (n-undecane)112-40-2
n-C14 (n-tetradecane)629-59-4
n-C16 (n-hexadecane)544-76-3
n-C18 (n-octadecane)593-45-3
n-C20 (n-eicosane)112-95-8
n-C22 (n-docosane)629-97-0
n-C24 (n-tetracosane)646-31-1
n-C26 (n-hexacosane)630-01-3
n-C28 (n-octacosane)630-02-4
n-C30 (n-triacontane)638-68-6
Captafol2425-06-1
Captan133-06-2
Carbaryl63-25-2
Carbazole86-74-8
Carbofuran1563-66-2
Carboxin5234-68 -4
Carbophenothion786-19-6
Chlordane
3 5		57-74-9
bis(2-Chloroethyl) ether
3 4		111-44-45.717.1
Chloroneb2675-77-6
4-Chloroaniline106-47-8
Chlorobenzilate510-15-6
Chlorfenvinphos470-90-6
4-Chloro-2-methylaniline95-69-2
3-(Chloromethyl)pyridine hydrochloride6959-48-4
4-Chloro-2-nitroaniline89-63-4
Chlorpropham101-21-3
Chlorothalonil1897-45-6
1-Chloronaphthalene90-13-1
3-Chloronitrobenzene121-73-3
4-Chloro-1,2-phenylenediamine95-83-0
4-Chloro-1,3-phenylenediamine5131-60-2
2-Chlorobiphenyl2051-60-7
Chlorpyrifos2921-88-2
Coumaphos56-72-4
m + p-Cresol65794-96-9
o-Cresol95-48-7
p-Cresidine120-71-8
Crotoxyphos7700-17-6
2-Cyclohexyl-4,6-dinitro-phenol131-89-5
Cyanazine21725-46-2
Cycloate1134-23-2
p-Cymene99-87-6
Dacthal (DCPA)1861-32-1
4,4′-DDD
3		72-54-82.88.4
4,4′-DDE
3		72-55-95.616.8
4,4′-DDT
3		50-29-34.714.1
Demeton-O298-03-3
Demeton-S126-75-0
Diallate (cis or trans)2303-16-4
2,4-Diaminotoluene95-80-7
Diazinon333-41-5
Dibenz(a,j)acridine224-42-0
Dibenzofuran132-64-9
Dibenzo(a,e)pyrene192-65-4
Dibenzothiophene132-65-0
1,2-Dibromo-3-chloropropane96-12-8
3,5-Dibromo-4-hydroxybenzonitrile1689-84-5
2,6-Di-tert-butyl-p-benzoquinone719-22-2
Dichlone117-80-6
2,3-Dichloroaniline608-27-5
2,3-Dichlorobiphenyl16605-91-7
2,6-Dichloro-4-nitroaniline99-30-9
2,3-Dichloronitrobenzene3209-22-1
1,3-Dichloro-2-propanol96-23-1
2,6-Dichlorophenol120-83-2
Dichlorvos62-73-7
Dicrotophos141-66-2
Dieldrin
3		60-57-12.57.5
1,2:3,4-Diepoxybutane1464-53-5
Di(2-ethylhexyl) adipate103-23-1
Diethylstilbestrol56-53-1
Diethyl sulfate64-67-5
Dilantin (5,5-Diphenylhydantoin)57-41-0
Dimethoate60-51-5
3,3′-Dimethoxybenzidine119-90-4
Dimethylaminoazobenzene60-11-7
7,12-Dimethylbenz(a)anthracene57-97-6
3,3′-Dimethylbenzidine119-93-7
N,N-Dimethylformamide68-12-2
3,6-Dimethylphenathrene1576-67-6
alpha, alpha-Dimethylphenethylamine122-09-8
Dimethyl sulfone67-71-0
1,2-Dinitrobenzene528-29-0
1,3-Dinitrobenzene99-65-0
1,4-Dinitrobenzene100-25-4
Dinocap39300-45-3
Dinoseb88-85-7
Diphenylamine122-39-4
Diphenyl ether101-84-8
1,2-Diphenylhydrazine122-66-7
Diphenamid957-51-7
Diphenyldisulfide882-33-7
Disulfoton298-04-4
Disulfoton sulfoxide2497-07-6
Disulfoton sulfone2497-06-5
Endosulfan I
4		959-98-8
Endosulfan II
3 4		33213-65-9
Endosulfan sulfate
3		1031-07-85.616.8
Endrin
3 4		72-20-8
Endrin aldehyde
3 4		7421-93-4
Endrin ketone
3 4		53494-70-5
EPN2104-64-5
EPTC759-94-4
Ethion563-12-2
Ethoprop13194-48-4
Ethyl carbamate51-79-6
Ethyl methanesulfonate65-50-0
Ethylenethiourea96-45-7
Etridiazole2593-15-9
Ethynylestradiol-3-methyl ether72-33-3
Famphur52-85-7
Fenamiphos22224-92-6
Fenarimol60168-88-9
Fensulfothion115-90-2
Fenthion55-38-9
Fluchloralin33245-39-5
Fluridone59756-60-4
Heptachlor
3		76-44-81.95.7
Heptachlor epoxide
3		1024-57-32.26.6
2,2′,3,3′,4,4′,6-Heptachlorobiphenyl52663-71-5
2,2′,4,4′,5′,6-Hexachlorobiphenyl60145-22-4
Hexachlorocyclopentadiene
3 4		77-47-4
Hexachlorophene70-30-4
Hexachloropropene1888-71-7
Hexamethylphosphoramide680-31-9
Hexanoic acid142-62-1
Hexazinone51235-04-2
Hydroquinone123-31-9
Isodrin465-73-6
2-Isopropylnaphthalene2027-17-0
Isosafrole120-58-1
Kepone143-50-0
Leptophos21609-90-5
Longifolene475-20-7
Malachite green569-64-2
Malathion121-75-5
Maleic anhydride108-31-6
Merphos150-50-5
Mestranol72-33-3
Methapyrilene91-80-5
Methoxychlor72-43-5
2-Methylbenzothioazole120-75-2
3-Methylcholanthrene56-49-5
4,4′-Methylenebis(2-chloroaniline)101-14-4
4,4′-Methylenebis(N,N-dimethylaniline)101-61-1
4,5-Methylenephenanthrene203-64-5
1-Methylfluorene1730-37-6
Methyl methanesulfonate66-27-3
2-Methylnaphthalene91-57-6
Methylparaoxon950-35-6
Methyl parathion298-00-0
1-Methylphenanthrene832-69-9
2-(Methylthio)benzothiazole615-22-5
Metolachlor5218-45-2
Metribuzin21087-64-9
Mevinphos7786-34-7
Mexacarbate315-18-4
MGK 264113-48-4
Mirex2385-85-5
Molinate2212-67-1
Monocrotophos6923-22-4
Naled300-76-5
Napropamide15299-99-7
1,4-Naphthoquinone130-15-4
1-Naphthylamine134-32-7
2-Naphthylamine91-59-8
1,5-Naphthalenediamine2243-62-1
Nicotine54-11-5
5-Nitroacenaphthene602-87-9
2-Nitroaniline88-74-4
3-Nitroaniline99-09-2
4-Nitroaniline100-01-6
5-Nitro-o-anisidine99-59-2
4-Nitrobiphenyl92-93-3
Nitrofen1836-75-5
5-Nitro-o-toluidine99-55-8
Nitroquinoline-1-oxide56-57-5
N-Nitrosodi-n-butylamine
4		924-16-3
N-Nitrosodiethylamine
4		55-18-5
N-Nitrosodimethylamine
3 4		62-75-9
N-Nitrosodiphenylamine
3 4		86-30-6
N-Nitrosomethylethylamine
4		10595-95-6
N-Nitrosomethylphenylamine
4		614-00-6
N-Nitrosomorpholine
4		59-89-2
N-Nitrosopiperidine
4		100-75-5
N-Nitrosopyrrolidine
4		930-55-2
trans-Nonachlor39765-80-5
Norflurazon27314-13-2
2,2′,3,3′,4,5′,6,6′-Octachlorobiphenyl40186-71-8
Octamethyl pyrophosphoramide152-16-9
4,4′-Oxydianiline101-80-4
Parathion56-38-2
PCB-1016
3 5		12674-11-2
PCB-1221
3 5		11104-28-23090
PCB-1232
3 5		11141-16-5
PCB-1242
3 5		53469-21-9
PCB-1248
3 5		12672-29-6
PCB-1254
3 5		11097-69-136108
PCB-1260
3 5		11098-82-5
PCB-1268
3 5		11100-14-4
Pebulate1114-71-2
Pentachlorobenzene608-93-5
Pentachloronitrobenzene82-68-8
2,2′,3,4′,6-Pentachlorobiphenyl68194-05-8
Pentachloroethane76-01-7
Pentamethylbenzene700-12-9
Perylene198-55-0
Phenacetin62-44-2
cis-Permethrin61949-76-6
trans-Permethrin61949-77-7
Phenobarbital50-06-6
Phenothiazene92-84-2
1,4-Phenylenediamine624-18-0
1-Phenylnaphthalene605-02-7
2-Phenylnaphthalene612-94-2
Phorate298-02-2
Phosalone2310-18-0
Phosmet732-11-6
Phosphamidon13171-21-6
Phthalic anhydride85-44-9
alpha-Picoline (2-Methylpyridine)109-06-8
Piperonyl sulfoxide120-62-7
Prometon1610-18-0
Prometryn7287-19-6
Pronamide23950-58-5
Propachlor1918-16-7
Propazine139-40-2
Propylthiouracil51-52-5
Pyridine110-86-1
Resorcinol (1,3-Benzenediol)108-46-3
Safrole94-59-7
Simazine122-34-9
Simetryn1014-70-6
Squalene7683-64-9
Stirofos22248-79-9
Strychnine57-24-9
Styrene
9		100-42-5
Sulfallate95-06-7
Tebuthiuron34014-18-1
Terbacil5902-51-2
Terbufos13071-79-9
Terbutryn886-50-0
alpha-Terpineol98-55-5
1,2,4,5-Tetrachlorobenzene95-94-3
2,2′,4,4′-Tetrachlorobiphenyl2437-79-8
2,3,7,8-Tetrachlorodibenzo-p-dioxin1746-01-6
2,3,4,6-Tetrachlorophenol58-90-2
Tetrachlorvinphos22248-79-9
Tetraethyl dithiopyrophosphate3689-24-5
Tetraethyl pyrophosphate107-49-3
Thianaphthene (2,3-Benzothiophene)95-15-8
Thioacetamide62-55-5
Thionazin297-97-2
Thiophenol (Benzenethiol)108-98-5
Thioxanthone492-22-8
Toluene-1,3-diisocyanate26471-62-5
Toluene-2,4-diisocyanate584-84-9
o-Toluidine95-53-4
Toxaphene
3 5		8001-35-2
Triadimefon43121-43-3
1,2,3-Trichlorobenzene87-61-6
2,4,5-Trichlorobiphenyl15862-07-4
2,3,6-Trichlorophenol933-75-5
2,4,5-Trichlorophenol95-95-4
Tricyclazole41814-78-2
Trifluralin1582-09-8
1,2,3-Trimethoxybenzene634-36-6
2,4,5-Trimethylaniline137-17-7
Trimethyl phosphate512-56-1
Triphenylene217-59-4
Tripropyleneglycolmethyl ether20324-33-8
1,3,5-Trinitrobenzene99-35-4
Tris(2,3-dibromopropyl) phosphate126-72-7
Tri-p-tolyl phosphate78-32-0
O,O,O-Triethyl phosphorothioate126-68-1
Trithiane291-29-4
Vernolate1929-77-7


1 Compounds that have been demonstrated amenable to extraction and gas chromatography.


2 Determine each analyte in the fraction that gives the most accurate result.


3 Priority Pollutant (40 CFR part 423, appendix A).


4 See section 1.2.


5 These compounds are mixtures of various isomers.


6 Detected as azobenzene.


7 MDL values from the 1984 promulgated version of Method 625.


8 ML = Minimum Level—see Glossary for definition and derivation.


9 Styrene may be susceptible to losses during sampling, preservation, and/or extraction of full-volume (1 L) water samples. However, styrene is not regulated at 40 CFR part 136, and it is also listed as an analyte in EPA Method 624.1 and EPA Method 1625C, where such losses may be less than using Method 625.1.


Table 4—Chromatographic Conditions and Characteristic m/z’s for Base/Neutral Extractables

Analyte
Retention time

(sec)
1
Characteristic m/z’s
Electron impact ionization
Chemical ionization
Primary
Second
Second
Methane
Methane
Methane
N-Nitrosodimethylamine385427444
bis(2-Chloroethyl) ether70493639563107109
bis(2-Chloroisopropyl) ether79945777977135137
Hexachloroethane823117201199199201203
N-Nitrosodi-n-propylamine83013042101
Nitrobenzene8497712365124152164
Isophorone8898295138139167178
bis(2-Chloroethoxy) methane939939512365107137
1,2,4-Trichlorobenzene958180182145181183209
Naphthalene967128129127129157169
Hexachlorobutadiene1006225223227223225227
Hexachlorocyclopentadiene1142237235272235237239
2-Chloronaphthalene1200162164127163191203
Acenaphthylene1247152151153152153181
Dimethyl phthalate1273163194164151163164
2,6-Dinitrotoluene130016589121183211223
Acenaphthene1304154153152154155183
2,4-Dinitrotoluene136416563182183211223
Fluorene1401166165167166167195
4-Chlorophenyl phenyl ether1409204206141
Diethyl phthalate1414149177150177223251
N-Nitrosodiphenylamine1464169168167169170198
4-Bromophenyl phenyl ether1498248250141249251277
alpha-BHC1514183181109
Hexachlorobenzene1522284142249284286288
beta-BHC1544183181109
gamma-BHC1557181183109
Phenanthrene1583178179176178179207
Anthracene1592178179176178179207
delta-BHC1599183109181
Heptachlor1683100272274
Di-n-butyl phthalate1723149150104149205279
Aldrin175366263220
Fluoranthene1817202101100203231243
Heptachlor epoxide1820353355351
gamma-Chlordane1834373375377
Pyrene1852202101100203231243
Benzidine
2		185318492185185213225
alpha-Chlordane1854373375377
Endosulfan I1855237339341
4,4′-DDE1892246248176
Dieldrin190779263279
Endrin19358126382
Endosulfan II2014237339341
4,4′-DDD2019235237165
Endrin aldehyde203167345250
Butyl benzyl phthalate206014991206149299327
Endosulfan sulfate2068272387422
4,4′-DDT2073235237165
Chrysene2083228226229228229257
3,3′-Dichlorobenzidine2086252254126
Benzo(a)anthracene2090228229226228229257
bis(2-Ethylhexyl) phthalate2124149167279149
Di-n-octyl phthalate22401494357
Benzo(b)fluoranthene2286252253125252253281
Benzo(k)fluoranthene2293252253125252253281
Benzo(a)pyrene2350252253125252253281
Indeno(1,2,3-cd) pyrene2650276138277276277305
Dibenz(a,h)anthracene2660278139279278279307
Benzo(ghi)perylene2750276138277276277305
Toxaphene159231233
PCB 1016224260294
PCB 1221190224260
PCB 1232190224260
PCB 1242224260294
PCB 1248294330262
PCB 1254294330362
PCB 1260330362394


1 Column: 30 m x 0.25 mm ID; 94% methyl, 5% phenyl, 1% vinyl bonded phase fused silica capillary.

Conditions: 5 min at 30 °C; 30-280 at 8 °C per min; isothermal at 280 °C until benzo(ghi)perylene elutes.

Gas velocity: 30 cm/sec at 30 °C (at constant pressure).


2 See section 1.2; included for tailing factor testing.


Table 5—Chromatographic Conditions and Characteristic m/z’s for Acid Extractables

Analyte
Retention Time

(sec)
1
Characteristic m/z’s
Electron impact ionization
Chemical ionization
Prime
Second
Second
Methane
Methane
Methane
2-Chlorophenol70512864130129131157
Phenol70094656695123135
2-Nitrophenol90013965109140168122
2,4-Dimethylphenol924122107121123151163
2,4-Dichlorophenol94716216498163165167
4-Chloro-3-methylphenol1091142107144143171183
2,4,6-Trichlorophenol1165196198200197199201
2,4-Dinitrophenol132518463154185213225
4-Nitrophenol135465139109140168122
2-Methyl-4,6-dinitrophenol143519818277199227239
Pentachlorophenol1561266264268267265269

Column: 30 m x 0.25 mm ID; 94% methyl, 5% phenyl, 1% vinyl bonded phase fused silica capillary.

Conditions: 5 min at 30 °C; 30-250 at 8 °C per min; isothermal at 280 °C until pentachlorophenol elutes.

Gas velocity: 30 cm/sec at 30 °C (at constant pressure).


Table 6—QC Acceptance Criteria—Method 625
1

Analyte
Range for Q

(%)
2
Limit for s

(%)
3
Range for

X (%)
3
Range for

P1, P2(%)
3
Limit for

RPD (%)
Acenaphthene70-1302960-13247-14548
Acenaphthylene60-1304554-12633-14574
Aldrin7-152397-152D-16681
Anthracene58-1304043-12027-13366
Benzo(a)anthracene42-1333242-13333-14353
Benzo(b)fluoranthene42-1404342-14024-15971
Benzo(k)fluoranthene25-1463825-14611-16263
Benzo(a)pyrene32-1484332-14817-16372
Benzo(ghi)perylene13-19561D-195D-21997
Benzyl butyl phthalate43-14036D-140D-15260
beta-BHC42-1313742-13124-14961
delta-BHCD-13077D-120D-120129
bis(2-Chloroethyl)ether52-1306543-12612-158108
bis(2-Chloroethoxy)methane52-1643249-16533-18454
bis(2-Chloroisopropyl) ether63-1394663-13936-16676
bis(2-Ethylhexyl) phthalate43-1375029-1378-15882
4-Bromophenyl phenyl ether70-1302665-12053-12743
2-Chloronaphthalene70-1301565-12060-12024
4-Chlorophenyl phenyl ether57-1453638-14525-15861
Chrysene44-1405344-14017-16887
4,4′-DDDD-13556D-135D-14593
4,4′-DDE19-1304619-1204-13677
4,4′-DDTD-17181D-171D-203135
Dibenz(a,h)anthracene13-20075D-200D-227126
Di-n-butyl phthalate52-130288-1201-12047
3,3′-Dichlorobenzidine18-213658-213D-262108
Dieldrin70-1303844-11929-13662
Diethyl phthalate47-13060D-120D-120100
Dimethyl phthalate50-130110D-120D-120183
2,4-Dinitrotoluene53-1302548-12739-13942
2,6-Dinitrotoluene68-1372968-13750-15848
Di-n-octyl phthalate21-1324219-1324-14669
Endosulfan sulfateD-13042D-120D-12070
Endrin aldehydeD-18945D-189D-20975
Fluoranthene47-1304043-12126-13766
Fluorene70-1302370-12059-12138
HeptachlorD-17244D-172D-19274
Heptachlor epoxide70-1306171-12026-155101
Hexachlorobenzene38-142338-142D-15255
Hexachlorobutadiene68-1303838-12024-12062
Hexachloroethane55-1303255-12040-12052
Indeno(1,2,3-cd)pyrene13-15160D-151D-17199
Isophorone52-1805647-18021-19693
Naphthalene70-1303936-12021-13365
Nitrobenzene54-1583754-15835-18062
N-Nitrosodi-n-propylamine59-1705214-198D-23087
PCB-126019-1307719-130D-164128
Phenanthrene67-1302465-12054-12039
Pyrene70-1303070-12052-12049
1,2,4-Trichlorobenzene61-1303057-13044-14250
4-Chloro-3-methylphenol68-1304441-12822-14773
2-Chlorophenol55-1303736-12023-13461
2,4-Dichlorophenol64-1303053-12239-13550
2,4-Dimethylphenol58-1303542-12032-12058
2,4-Dinitrophenol39-17379D-173D-191132
2-Methyl-4,6-dinitrophenol56-13012253-130D-181203
2-Nitrophenol61-1633345-16729-18255
4-Nitrophenol35-1307913-129D-132131
Pentachlorophenol42-1525238-15214-17686
Phenol48-1303917-1205-12064
2,4,6-Trichlorophenol69-1303552-12937-14458


1 Acceptance criteria are based upon method performance data in Table 7 and from EPA Method 1625. Where necessary, limits for recovery have been broadened to assure applicability to concentrations below those used to develop Table 7.


2 Test concentration = 100 µg/mL.


3 Test concentration = 100 µg/L.

Q = Calibration verification (sections 7.3.1 and 13.4).

s = Standard deviation for four recovery measurements in the DOC test (section 8.2.4).

X = Average recovery for four recovery measurements in the DOC test (section 8.2.4).

P1, P2 = MS/MSD recovery (section 8.3.2, section 8.4.2).

RPD = MS/MSD relative percent difference (RPD; section 8.3.3).

D = Detected; result must be greater than zero.


Table 7—Precision and Recovery as Functions of Concentration—Method 625
1

Analyte
Recovery, X′

(µg/L)
Single analyst

precision, sr′

(µg/L)
Overall

precision, S′

(µg/L)
Acenaphthene0.96C + 0.190.15 X−0.120.21 X−0.67
Acenaphthylene0.89C + 0.740.24 X−1.060.26 X−0.54
Aldrin0.78C + 1.660.27 X−1.280.43 X + 1.13
Anthracene0.80C + 0.680.21 X−0.320.27 X−0.64
Benzo(a)anthracene0.88C−0.600.15 X + 0.930.26 X−0.28
Benzo(b)fluoranthene0.93C−1.800.22 X + 0.430.29 X + 0.96
Benzo(k)fluoranthene0.87C−1.560.19 X + 1.030.35 X + 0.40
Benzo(a)pyrene0.90C−0.130.22 X + 0.480.32 X + 1.35
Benzo(ghi)perylene0.98C−0.860.29 X + 2.400.51 X−0.44
Benzyl butyl phthalate0.66C−1.680.18 X + 0.940.53 X + 0.92
beta-BHC0.87C−0.940.20 X−0.580.30 X−1.94
delta-BHC0.29C−1.090.34 X + 0.860.93 X−0.17
bis(2-Chloroethyl) ether0.86C−1.540.35 X−0.990.35 X + 0.10
bis(2-Chloroethoxy) methane1.12C−5.040.16 X + 1.340.26 X + 2.01
bis(2-Chloroisopropyl) ether1.03C−2.310.24 X + 0.280.25 X + 1.04
bis(2-Ethylhexyl) phthalate0.84C−1.180.26 X + 0.730.36 X + 0.67
4-Bromophenyl phenyl ether0.91C−1.340.13 X + 0.660.16 X + 0.66
2-Chloronaphthalene0.89C + 0.010.07 X + 0.520.13 X + 0.34
4-Chlorophenyl phenyl ether0.91C + 0.530.20 X−0.940.30 X−0.46
Chrysene0.93C−1.000.28 X + 0.130.33 X−0.09
4,4′-DDD0.56C−0.400.29 X−0.320.66 X−0.96
4,4′-DDE0.70C−0.540.26 X−1.170.39 X−1.04
4,4′-DDT0.79C−3.280.42 X + 0.190.65 X−0.58
Dibenz(a,h)anthracene0.88C + 4.720.30 X + 8.510.59 X + 0.25
Di-n-butyl phthalate0.59C + 0.710.13 X + 1.160.39 X + 0.60
3,3′-Dichlorobenzidine1.23C−12.650.28 X + 7.330.47 X + 3.45
Dieldrin0.82C−0.160.20 X−0.160.26 X−0.07
Diethyl phthalate0.43C + 1.000.28 X + 1.440.52 X + 0.22
Dimethyl phthalate0.20C + 1.030.54 X + 0.191.05 X−0.92
2,4-Dinitrotoluene0.92C−4.810.12 X + 1.060.21 X + 1.50
2,6-Dinitrotoluene1.06C−3.600.14 X + 1.260.19 X + 0.35
Di-n-octyl phthalate0.76C−0.790.21 X + 1.190.37 X + 1.19
Endosulfan sulfate0.39C + 0.410.12 X + 2.470.63 X−1.03
Endrin aldehyde0.76C−3.860.18 X + 3.910.73 X−0.62
Fluoranthene0.81C + 1.100.22 X + 0.730.28 X−0.60
Fluorene0.90C−0.000.12 X + 0.260.13 X + 0.61
Heptachlor0.87C−2.970.24 X−0.560.50 X−0.23
Heptachlor epoxide0.92C−1.870.33 X−0.460.28 X + 0.64
Hexachlorobenzene0.74C + 0.660.18 X−0.100.43 X−0.52
Hexachlorobutadiene0.71C−1.010.19 X + 0.920.26 X + 0.49
Hexachloroethane0.73C−0.830.17 X + 0.670.17 X + 0.80
Indeno(1,2,3-cd)pyrene0.78C−3.100.29 X + 1.460.50 X + 0.44
Isophorone1.12C + 1.410.27 X + 0.770.33 X + 0.26
Naphthalene0.76C + 1.580.21 X−0.410.30 X−0.68
Nitrobenzene1.09C−3.050.19 X + 0.920.27 X + 0.21
N-Nitrosodi-n-propylamine1.12C−6.220.27 X + 0.680.44 X + 0.47
PCB-12600.81C−10.860.35 X + 3.610.43 X + 1.82
Phenanthrene0.87C−0.060.12 X + 0.570.15 X + 0.25
Pyrene0.84C−0.160.16 X + 0.060.15 X + 0.31
1,2,4-Trichlorobenzene0.94C−0.790.15 X + 0.850.21 X + 0.39
4-Chloro-3-methylphenol0.84C + 0.350.23 X + 0.750.29 X + 1.31
2-Chlorophenol0.78C + 0.290.18 X + 1.460.28 X + 0.97
2,4-Dichlorophenol0.87C + 0.130.15 X + 1.250.21 X + 1.28
2,4-Dimethylphenol0.71C + 4.410.16 X + 1.210.22 X + 1.31
2,4-Dinitrophenol0.81C−18.040.38 X + 2.360.42 X + 26.29
2-Methyl-4,6-Dinitrophenol1.04C−28.040.05 X + 42.290.26 X + 23.10
2-Nitrophenol1.07C−1.150.16 X + 1.940.27 X + 2.60
4-Nitrophenol0.61C−1.220.38 X + 2.570.44 X + 3.24
Pentachlorophenol0.93C + 1.990.24 X + 3.030.30 X + 4.33
Phenol0.43C + 1.260.26 X + 0.730.35 X + 0.58
2,4,6-Trichlorophenol0.91C−0.180.16 X + 2.220.22 X + 1.81


1 Regressions based on data from Reference 2.

X′ = Expected recovery for one or more measurements of a sample containing a concentration of C, in µg/L.

sr′ = Expected single analyst standard deviation of measurements at an average concentration found of X, in µg/L.

S′ = Expected interlaboratory standard deviation of measurements at an average concentration found of X, in µg/L.

C = True value for the concentration, in µg/L.

X = Average recovery found for measurements of samples containing a concentration of C, in µg/L.


Table 8—Suggested Internal and Surrogate Standards

Base/neutral fraction
Range for surrogate recovery (%)
1
Calibration verification
Recovery from samples
Acenaphthalene-d866-15233-168
Acenaphthene-d1071-14130-180
Aniline-d5
Anthracene-d1058-17123-142
Benzo(a)anthracene-d1228-35722-329
Benzo(a)pyrene-d1232-19432-194
4-Chloroaniline-d41-1451-145
bis(2-Chloroethyl) ether-d852-19425-222
Chrysene-d1223-29023-290
Decafluorobiphenyl
4,4′-Dibromobiphenyl
4,4′-Dibromooctafluorobiphenyl
1,4-Dichlorobenzene-d465-15311-245
2,2′-Difluorobiphenyl
Dimethyl phthalate-d647-2111-500
Fluoranthene-d1047-21530-187
Fluorene-d1061-16438-172
4-Fluoroaniline
1-Fluoronaphthalene
2-Fluoronaphthalene
2-Methylnaphthalene-d1050-15050-150
Naphthalene-d871-14122-192
Nitrobenzene-d546-21915-314
2,3,4,5,6-Pentafluorobiphenyl
Perylene-d12
Phenanthrene-d1067-14934-168
Pyrene-d1048-21028-196
Pyridine-d5
Acid fraction
2-Chlorophenol-d455-18033-180
2,4-Dichlorophenol-d364-15734-182
4,6-Dinitro-2-methylphenol-d256-17722-307
2-Fluorophenol
4-Methylphenol-d825-11125-111
2-Nitrophenol-d461-16337-163
4-Nitrophenol-d435-2876-500
Pentafluorophenol
2-Perfluoromethylphenol
Phenol-d548-2088-424


1 Recovery from samples is the wider of the criteria in the CLP SOW for organics or in Method 1625.


Table 9A—DFTPP Key m/z’s and Abundance Criteria for Quadrupole Instruments
1

m/z
Abundance criteria
5130-60 percent of m/z 198.
68Less than 2 percent of m/z 69.
70Less than 2 percent of m/z 69.
12740-60 percent of base peak m/z 198.
197Less than 1 percent of m/z 198.
198Base peak, 100 percent relative abundance.
1995-9 percent of m/z 198.
27510-30 percent of m/z 198.
365Greater than 1 percent of m/z 198.
441Present but less than m/z 443.
44240-100 percent of m/z 198.
44317-23 percent of m/z 442.


1 Criteria in these tables are for quadrupole and time-of-flight instruments. Alternative tuning criteria from other published EPA reference methods may be used provided method performance is not adversely affected. Alternative tuning criteria specified by an instrument manufacturer may also be used for another type of mass spectrometer, provided method performance is not adversely affected.


Table 9B—DFTPP Key m/z’s and Abundance Criteria for Time-of-flight Instruments
1

m/z
Abundance criteria
5110-85 percent of the base peak.
68Less than 2 percent of m/z 69.
70Less than 2 percent of m/z 69.
12710-80 percent of the base peak.
197Less than 2 percent of Mass 198.
198Base peak, or greater than 50% of m/z 442.
1995-9 percent of m/z 198.
27510-60 percent of the base peak.
365Greater than 0.5 percent of m/z 198.
441Less than 150 percent of m/z 443.
442Base peak or greater than 30 percent of m/z 198.
44315-24 percent of m/z 442.


1 Criteria in these tables are for quadrupole and time-of-flight instruments. Alternative tuning criteria from other published EPA reference methods may be used provided method performance is not adversely affected. Alternative tuning criteria specified by an instrument manufacturer may also be used for another type of mass spectrometer, or for an alternative carrier gas, provided method performance is not adversely affected.


21. Figures



22. Glossary

These definitions and purposes are specific to this method but have been conformed to common usage to the extent possible.


22.1 Units of weight and measure and their abbreviations.


22.1.1 Symbols.


°C degrees Celsius

µg microgram

µL microliter


> greater than

≤ less than or equal to

% percent

22.1.2 Abbreviations (in alphabetical order).


cm centimeter

g gram

h hour

ID inside diameter

in. inch

L liter

m mass or meter

mg milligram

min minute

mL milliliter

mm millimeter

ms millisecond

m/z mass-to-charge ratio

N normal; gram molecular weight of solute divided by hydrogen equivalent of solute, per liter of solution

ng nanogram

pg picogram

ppb part-per-billion

ppm part-per-million

ppt part-per-trillion

psig pounds-per-square inch gauge

22.2 Definitions and acronyms (in alphabetical order).


Analyte—A compound or mixture of compounds (e.g., PCBs) tested for by this method. The analytes are listed in Tables 1-3.


Batch—See Extraction.


Blank—An aliquot of reagent water that is treated exactly as a sample including exposure to all glassware, equipment, solvents, reagents, internal standards, and surrogates that are used with samples. The blank is used to determine if analytes or interferences are present in the laboratory environment, the reagents, or the apparatus.


Calibration—The process of determining the relationship between the output or response of a measuring instrument and the value of an input standard. Historically, EPA has referred to a multi-point calibration as the “initial calibration,” to differentiate it from a single-point calibration verification.


Calibration standard—A solution prepared from stock solutions and/or a secondary standards and containing the analytes of interest, surrogates, and internal standards. The calibration standard is used to calibrate the response of the GC/MS instrument against analyte concentration.


Calibration verification standard—The mid-point calibration standard used to verify calibration. See sections 7.3 and 13.4.


Descriptor—In SIM, the beginning and ending retention times for the RT window, the m/z’s sampled in the RT window, and the dwell time at each m/z.


Extracted ion current profile (EICP)—The line described by the signal at a given m/z.


Extraction Batch—A set of up to 20 field samples (not including QC samples) started through the extraction process on a given 24-hour shift (section 3.1). Each extraction batch must be accompanied by a blank (section 8.5), a laboratory control sample (LCS, section 8.4), and a matrix spike and duplicate (MS/MSD; Section 8.3), resulting in a minimum of five analyses (1 sample, 1 blank, 1 LCS, 1 MS, and 1 MSD) and a maximum of 24 analyses (20 field samples, 1 blank, 1 LCS, 1 MS, and 1 MSD) for the batch. If greater than 20 samples are to be extracted in a 24-hour shift, the samples must be separated into extraction batches of 20 or fewer samples.


Field Duplicates—Two samples collected at the same time and placed under identical conditions, and treated identically throughout field and laboratory procedures. Results of analyses of the field duplicates provide an estimate of the precision associated with sample collection, preservation, and storage, as well as with laboratory procedures.


Field blank—An aliquot of reagent water or other reference matrix that is placed in a sample container in the field, and treated as a sample in all respects, including exposure to sampling site conditions, storage, preservation, and all analytical procedures. The purpose of the field blank is to determine if the field or sample transporting procedures and environments have contaminated the sample.


GC—Gas chromatograph or gas chromatography.


Internal standard—A compound added to an extract or standard solution in a known amount and used as a reference for quantitation of the analytes of interest and surrogates. In this method the internal standards are stable isotopically labeled analogs of selected method analytes (Table 8). Also see Internal standard quantitation.


Internal standard quantitation—A means of determining the concentration of an analyte of interest (Tables 1-3) by reference to a compound not expected to be found in a sample.


DOC—Initial demonstration of capability (section 8.2); four aliquots of reagent water spiked with the analytes of interest and analyzed to establish the ability of the laboratory to generate acceptable precision and recovery. A DOC is performed prior to the first time this method is used and any time the method or instrumentation is modified.


Laboratory Control Sample (LCS; laboratory fortified blank; section 8.4)—An aliquot of reagent water spiked with known quantities of the analytes of interest and surrogates. The LCS is analyzed exactly like a sample. Its purpose is to assure that the results produced by the laboratory remain within the limits specified in this method for precision and recovery.


Laboratory fortified sample matrix—See Matrix spike.


Laboratory reagent blank—A blank run on laboratory reagents; e.g., methylene chloride (section 11.1.5).


Matrix spike (MS) and matrix spike duplicate (MSD) (laboratory fortified sample matrix and duplicate)—Two aliquots of an environmental sample to which known quantities of the analytes of interest and surrogates are added in the laboratory. The MS/MSD are prepared and analyzed exactly like a field sample. Their purpose is to quantify any additional bias and imprecision caused by the sample matrix. The background concentrations of the analytes in the sample matrix must be determined in a separate aliquot and the measured values in the MS/MSD corrected for background concentrations.


May—This action, activity, or procedural step is neither required nor prohibited.


May not—This action, activity, or procedural step is prohibited.


Method blank—See blank.


Method detection limit (MDL)—A detection limit determined by the procedure at 40 CFR part 136, appendix B. The MDLs determined by EPA in the original version of the method are listed in Tables 1, 2 and 3. As noted in section 1.5, use the MDLs in Tables 1, 2, and 3 in conjunction with current MDL data from the laboratory actually analyzing samples to assess the sensitivity of this procedure relative to project objectives and regulatory requirements (where applicable).


Minimum level (ML)—The term “minimum level” refers to either the sample concentration equivalent to the lowest calibration point in a method or a multiple of the method detection limit (MDL), whichever is higher. Minimum levels may be obtained in several ways: They may be published in a method; they may be based on the lowest acceptable calibration point used by a laboratory; or they may be calculated by multiplying the MDL in a method, or the MDL determined by a laboratory, by a factor of 3. For the purposes of NPDES compliance monitoring, EPA considers the following terms to be synonymous: “quantitation limit,” “reporting limit,” and “minimum level.”


MS—Mass spectrometer or mass spectrometry, or matrix spike (a QC sample type).


MSD—Matrix spike duplicate (a QC sample type).


Must—This action, activity, or procedural step is required.


m/z—The ratio of the mass of an ion (m) detected in the mass spectrometer to the charge (z) of that ion.


Preparation blank—See blank.


Quality control check sample (QCS)—See Laboratory Control Sample.


Reagent water—Water demonstrated to be free from the analytes of interest and potentially interfering substances at the MDLs for the analytes in this method.


Regulatory compliance limit (or regulatory concentration limit)—A limit on the concentration or amount of a pollutant or contaminant specified in a nationwide standard, in a permit, or otherwise established by a regulatory/control authority.


Relative retention time (RRT)—The ratio of the retention time of an analyte to the retention time of its associated internal standard. RRT compensates for small changes in the GC temperature program that can affect the absolute retention times of the analyte and internal standard. RRT is a unitless quantity.


Relative standard deviation (RSD)—The standard deviation times 100 divided by the mean. Also termed “coefficient of variation.”


RF—Response factor. See section 7.2.2.


RSD—See relative standard deviation.


Safety Data Sheet (SDS)—Written information on a chemical’s toxicity, health hazards, physical properties, fire, and reactivity, including storage, spill, and handling precautions that meet the requirements of OSHA, 29 CFR 1910.1200(g) and appendix D to § 1910.1200. United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS), third revised edition, United Nations, 2009.


Selected Ion Monitoring (SIM)—An MS technique in which a few m/z’s are monitored. When used with gas chromatography, the m/z’s monitored are usually changed periodically throughout the chromatographic run, to correlate with the characteristic m/z’s of the analytes, surrogates, and internal standards as they elute from the chromatographic column. The technique is often used to increase sensitivity and minimize interferences.


Signal-to-noise ratio (S/N)—The height of the signal as measured from the mean (average) of the noise to the peak maximum divided by the width of the noise.


Should—This action, activity, or procedural step is suggested but not required.


SPE—Solid-phase extraction; an extraction technique in which an analyte is extracted from an aqueous solution by passage over or through a material capable of reversibly adsorbing the analyte. Also termed liquid-solid extraction.


Stock solution—A solution containing an analyte that is prepared using a reference material traceable to EPA, the National Institute of Science and Technology (NIST), or a source that will attest to the purity, authenticity, and concentration of the standard.


Surrogate—A compound unlikely to be found in a sample, and which is spiked into sample in a known amount before extraction or other processing, and is quantitated with the same procedures used to quantify other sample components. The purpose of the surrogate is to monitor method performance with each sample.


Method 1613, Revision B

Tetra- Through Octa-Chlorinated Dioxins and Furans by Isotope Dilution HRGC/HRMS

1.0 Scope and Application

1.1 This method is for determination of tetra- through octa-chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs) in water, soil, sediment, sludge, tissue, and other sample matrices by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). The method is for use in EPA’s data gathering and monitoring programs associated with the Clean Water Act, the Resource Conservation and Recovery Act, the Comprehensive Environmental Response, Compensation and Liability Act, and the Safe Drinking Water Act. The method is based on a compilation of EPA, industry, commercial laboratory, and academic methods (References 1-6).


1.2 The seventeen 2,3,7,8-substituted CDDs/CDFs listed in Table 1 may be determined by this method. Specifications are also provided for separate determination of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) and 2,3,7,8-tetrachloro-dibenzofuran (2,3,7,8-TCDF).


1.3 The detection limits and quantitation levels in this method are usually dependent on the level of interferences rather than instrumental limitations. The minimum levels (MLs) in Table 2 are the levels at which the CDDs/CDFs can be determined with no interferences present. The Method Detection Limit (MDL) for 2,3,7,8-TCDD has been determined as 4.4 pg/L (parts-per-quadrillion) using this method.


1.4 The GC/MS portions of this method are for use only by analysts experienced with HRGC/HRMS or under the close supervision of such qualified persons. Each laboratory that uses this method must demonstrate the ability to generate acceptable results using the procedure in Section 9.2.


1.5 This method is “performance-based”. The analyst is permitted to modify the method to overcome interferences or lower the cost of measurements, provided that all performance criteria in this method are met. The requirements for establishing method equivalency are given in Section 9.1.2.


1.6 Any modification of this method, beyond those expressly permitted, shall be considered a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


2.0 Summary of Method

Flow charts that summarize procedures for sample preparation, extraction, and analysis are given in Figure 1 for aqueous and solid samples, Figure 2 for multi-phase samples, and Figure 3 for tissue samples.


2.1 Extraction.


2.1.1 Aqueous samples (samples containing less than 1% solids)—Stable isotopically labeled analogs of 15 of the 2,3,7,8-substituted CDDs/CDFs are spiked into a 1 L sample, and the sample is extracted by one of three procedures:


2.1.1.1 Samples containing no visible particles are extracted with methylene chloride in a separatory funnel or by the solid-phase extraction technique summarized in Section 2.1.1.3. The extract is concentrated for cleanup.


2.1.1.2 Samples containing visible particles are vacuum filtered through a glass-fiber filter. The filter is extracted in a Soxhlet/Dean-Stark (SDS) extractor (Reference 7), and the filtrate is extracted with methylene chloride in a separatory funnel. The methylene chloride extract is concentrated and combined with the SDS extract prior to cleanup.


2.1.1.3 The sample is vacuum filtered through a glass-fiber filter on top of a solid-phase extraction (SPE) disk. The filter and disk are extracted in an SDS extractor, and the extract is concentrated for cleanup.


2.1.2 Solid, semi-solid, and multi-phase samples (but not tissue)—The labeled compounds are spiked into a sample containing 10 g (dry weight) of solids. Samples containing multiple phases are pressure filtered and any aqueous liquid is discarded. Coarse solids are ground or homogenized. Any non-aqueous liquid from multi-phase samples is combined with the solids and extracted in an SDS extractor. The extract is concentrated for cleanup.


2.1.3 Fish and other tissue—The sample is extracted by one of two procedures:


2.1.3.1 Soxhlet or SDS extraction—A 20 g aliquot of sample is homogenized, and a 10 g aliquot is spiked with the labeled compounds. The sample is mixed with sodium sulfate, allowed to dry for 12-24 hours, and extracted for 18-24 hours using methylene chloride:hexane (1:1) in a Soxhlet extractor. The extract is evaporated to dryness, and the lipid content is determined.


2.1.3.2 HCl digestion—A 20 g aliquot is homogenized, and a 10 g aliquot is placed in a bottle and spiked with the labeled compounds. After equilibration, 200 mL of hydrochloric acid and 200 mL of methylene chloride:hexane (1:1) are added, and the bottle is agitated for 12-24 hours. The extract is evaporated to dryness, and the lipid content is determined.


2.2 After extraction,
37Cl4-labeled 2,3,7,8-TCDD is added to each extract to measure the efficiency of the cleanup process. Sample cleanups may include back-extraction with acid and/or base, and gel permeation, alumina, silica gel, Florisil and activated carbon chromatography. High-performance liquid chromatography (HPLC) can be used for further isolation of the 2,3,7,8-isomers or other specific isomers or congeners. Prior to the cleanup procedures cited above, tissue extracts are cleaned up using an anthropogenic isolation column, a batch silica gel adsorption, or sulfuric acid and base back-extraction, depending on the tissue extraction procedure used.


2.3 After cleanup, the extract is concentrated to near dryness. Immediately prior to injection, internal standards are added to each extract, and an aliquot of the extract is injected into the gas chromatograph. The analytes are separated by the GC and detected by a high-resolution (≥10,000) mass spectrometer. Two exact m/z’s are monitored for each analyte.


2.4 An individual CDD/CDF is identified by comparing the GC retention time and ion-abundance ratio of two exact m/z’s with the corresponding retention time of an authentic standard and the theoretical or acquired ion-abundance ratio of the two exact m/z’s. The non-2,3,7,8 substituted isomers and congeners are identified when retention times and ion-abundance ratios agree within predefined limits. Isomer specificity for 2,3,7,8-TCDD and 2,3,7,8-TCDF is achieved using GC columns that resolve these isomers from the other tetra-isomers.


2.5 Quantitative analysis is performed using selected ion current profile (SICP) areas, in one of three ways:


2.5.1 For the 15 2,3,7,8-substituted CDDs/CDFs with labeled analogs (see Table 1), the GC/MS system is calibrated, and the concentration of each compound is determined using the isotope dilution technique.


2.5.2 For 1,2,3,7,8,9-HxCDD, OCDF, and the labeled compounds, the GC/MS system is calibrated and the concentration of each compound is determined using the internal standard technique.


2.5.3 For non-2,3,7,8-substituted isomers and for all isomers at a given level of chlorination (i.e., total TCDD), concentrations are determined using response factors from calibration of the CDDs/CDFs at the same level of chlorination.


2.6 The quality of the analysis is assured through reproducible calibration and testing of the extraction, cleanup, and GC/MS systems.


3.0 Definitions

Definitions are given in the glossary at the end of this method.


4.0 Contamination and Interferences

4.1 Solvents, reagents, glassware, and other sample processing hardware may yield artifacts and/or elevated baselines causing misinterpretation of chromatograms (References 8-9). Specific selection of reagents and purification of solvents by distillation in all-glass systems may be required. Where possible, reagents are cleaned by extraction or solvent rinse.


4.2 Proper cleaning of glassware is extremely important, because glassware may not only contaminate the samples but may also remove the analytes of interest by adsorption on the glass surface.


4.2.1 Glassware should be rinsed with solvent and washed with a detergent solution as soon after use as is practical. Sonication of glassware containing a detergent solution for approximately 30 seconds may aid in cleaning. Glassware with removable parts, particularly separatory funnels with fluoropolymer stopcocks, must be disassembled prior to detergent washing.


4.2.2 After detergent washing, glassware should be rinsed immediately, first with methanol, then with hot tap water. The tap water rinse is followed by another methanol rinse, then acetone, and then methylene chloride.


4.2.3 Do not bake reusable glassware in an oven as a routine part of cleaning. Baking may be warranted after particularly dirty samples are encountered but should be minimized, as repeated baking of glassware may cause active sites on the glass surface that will irreversibly adsorb CDDs/CDFs.


4.2.4 Immediately prior to use, the Soxhlet apparatus should be pre-extracted with toluene for approximately three hours (see Sections 12.3.1 through 12.3.3). Separatory funnels should be shaken with methylene chloride/toluene (80/20 mixture) for two minutes, drained, and then shaken with pure methylene chloride for two minutes.


4.3 All materials used in the analysis shall be demonstrated to be free from interferences by running reference matrix method blanks initially and with each sample batch (samples started through the extraction process on a given 12-hour shift, to a maximum of 20 samples).


4.3.1 The reference matrix must simulate, as closely as possible, the sample matrix under test. Ideally, the reference matrix should not contain the CDDs/CDFs in detectable amounts, but should contain potential interferents in the concentrations expected to be found in the samples to be analyzed. For example, a reference sample of human adipose tissue containing pentachloronaphthalene can be used to exercise the cleanup systems when samples containing pentachloronaphthalene are expected.


4.3.2 When a reference matrix that simulates the sample matrix under test is not available, reagent water (Section 7.6.1) can be used to simulate water samples; playground sand (Section 7.6.2) or white quartz sand (Section 7.3.2) can be used to simulate soils; filter paper (Section 7.6.3) can be used to simulate papers and similar materials; and corn oil (Section 7.6.4) can be used to simulate tissues.


4.4 Interferences coextracted from samples will vary considerably from source to source, depending on the diversity of the site being sampled. Interfering compounds may be present at concentrations several orders of magnitude higher than the CDDs/CDFs. The most frequently encountered interferences are chlorinated biphenyls, methoxy biphenyls, hydroxydiphenyl ethers, benzylphenyl ethers, polynuclear aromatics, and pesticides. Because very low levels of CDDs/CDFs are measured by this method, the elimination of interferences is essential. The cleanup steps given in Section 13 can be used to reduce or eliminate these interferences and thereby permit reliable determination of the CDDs/CDFs at the levels shown in Table 2.


4.5 Each piece of reusable glassware should be numbered to associate that glassware with the processing of a particular sample. This will assist the laboratory in tracking possible sources of contamination for individual samples, identifying glassware associated with highly contaminated samples that may require extra cleaning, and determining when glassware should be discarded.


4.6 Cleanup of tissue—The natural lipid content of tissue can interfere in the analysis of tissue samples for the CDDs/CDFs. The lipid contents of different species and portions of tissue can vary widely. Lipids are soluble to varying degrees in various organic solvents and may be present in sufficient quantity to overwhelm the column chromatographic cleanup procedures used for cleanup of sample extracts. Lipids must be removed by the lipid removal procedures in Section 13.7, followed by alumina (Section 13.4) or Florisil (Section 13.8), and carbon (Section 13.5) as minimum additional cleanup steps. If chlorodiphenyl ethers are detected, as indicated by the presence of peaks at the exact m/z’s monitored for these interferents, alumina and/or Florisil cleanup must be employed to eliminate these interferences.


5.0 Safety

5.1 The toxicity or carcinogenicity of each compound or reagent used in this method has not been precisely determined; however, each chemical compound should be treated as a potential health hazard. Exposure to these compounds should be reduced to the lowest possible level.


5.1.1 The 2,3,7,8-TCDD isomer has been found to be acnegenic, carcinogenic, and teratogenic in laboratory animal studies. It is soluble in water to approximately 200 ppt and in organic solvents to 0.14%. On the basis of the available toxicological and physical properties of 2,3,7,8-TCDD, all of the CDDs/CDFs should be handled only by highly trained personnel thoroughly familiar with handling and cautionary procedures and the associated risks.


5.1.2 It is recommended that the laboratory purchase dilute standard solutions of the analytes in this method. However, if primary solutions are prepared, they shall be prepared in a hood, and a NIOSH/MESA approved toxic gas respirator shall be worn when high concentrations are handled.


5.2 The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material safety data sheets (MSDSs) should also be made available to all personnel involved in these analyses. It is also suggested that the laboratory perform personal hygiene monitoring of each analyst who uses this method and that the results of this monitoring be made available to the analyst. Additional information on laboratory safety can be found in References 10-13. The references and bibliography at the end of Reference 13 are particularly comprehensive in dealing with the general subject of laboratory safety.


5.3 The CDDs/CDFs and samples suspected to contain these compounds are handled using essentially the same techniques employed in handling radioactive or infectious materials. Well-ventilated, controlled access laboratories are required. Assistance in evaluating the health hazards of particular laboratory conditions may be obtained from certain consulting laboratories and from State Departments of Health or Labor, many of which have an industrial health service. The CDDs/CDFs are extremely toxic to laboratory animals. Each laboratory must develop a strict safety program for handling these compounds. The practices in References 2 and 14 are highly recommended.


5.3.1 Facility—When finely divided samples (dusts, soils, dry chemicals) are handled, all operations (including removal of samples from sample containers, weighing, transferring, and mixing) should be performed in a glove box demonstrated to be leak tight or in a fume hood demonstrated to have adequate air flow. Gross losses to the laboratory ventilation system must not be allowed. Handling of the dilute solutions normally used in analytical and animal work presents no inhalation hazards except in the case of an accident.


5.3.2 Protective equipment—Disposable plastic gloves, apron or lab coat, safety glasses or mask, and a glove box or fume hood adequate for radioactive work should be used. During analytical operations that may give rise to aerosols or dusts, personnel should wear respirators equipped with activated carbon filters. Eye protection equipment (preferably full face shields) must be worn while working with exposed samples or pure analytical standards. Latex gloves are commonly used to reduce exposure of the hands. When handling samples suspected or known to contain high concentrations of the CDDs/CDFs, an additional set of gloves can also be worn beneath the latex gloves.


5.3.3 Training—Workers must be trained in the proper method of removing contaminated gloves and clothing without contacting the exterior surfaces.


5.3.4 Personal hygiene—Hands and forearms should be washed thoroughly after each manipulation and before breaks (coffee, lunch, and shift).


5.3.5 Confinement—Isolated work areas posted with signs, segregated glassware and tools, and plastic absorbent paper on bench tops will aid in confining contamination.


5.3.6 Effluent vapors—The effluents of sample splitters from the gas chromatograph (GC) and from roughing pumps on the mass spectrometer (MS) should pass through either a column of activated charcoal or be bubbled through a trap containing oil or high-boiling alcohols to condense CDD/CDF vapors.


5.3.7 Waste Handling—Good technique includes minimizing contaminated waste. Plastic bag liners should be used in waste cans. Janitors and other personnel must be trained in the safe handling of waste.


5.3.8 Decontamination


5.3.8.1 Decontamination of personnel—Use any mild soap with plenty of scrubbing action.


5.3.8.2 Glassware, tools, and surfaces—Chlorothene NU Solvent is the least toxic solvent shown to be effective. Satisfactory cleaning may be accomplished by rinsing with Chlorothene, then washing with any detergent and water. If glassware is first rinsed with solvent, then the dish water may be disposed of in the sewer. Given the cost of disposal, it is prudent to minimize solvent wastes.


5.3.9 Laundry—Clothing known to be contaminated should be collected in plastic bags. Persons who convey the bags and launder the clothing should be advised of the hazard and trained in proper handling. The clothing may be put into a washer without contact if the launderer knows of the potential problem. The washer should be run through a cycle before being used again for other clothing.


5.3.10 Wipe tests—A useful method of determining cleanliness of work surfaces and tools is to wipe the surface with a piece of filter paper. Extraction and analysis by GC with an electron capture detector (ECD) can achieve a limit of detection of 0.1 µg per wipe; analysis using this method can achieve an even lower detection limit. Less than 0.1 µg per wipe indicates acceptable cleanliness; anything higher warrants further cleaning. More than 10 µg on a wipe constitutes an acute hazard and requires prompt cleaning before further use of the equipment or work space, and indicates that unacceptable work practices have been employed.


5.3.11 Table or wrist-action shaker—The use of a table or wrist-action shaker for extraction of tissues presents the possibility of breakage of the extraction bottle and spillage of acid and flammable organic solvent. A secondary containment system around the shaker is suggested to prevent the spread of acid and solvents in the event of such a breakage. The speed and intensity of shaking action should also be adjusted to minimize the possibility of breakage.


6.0 Apparatus and Materials


Note:

Brand names, suppliers, and part numbers are for illustration purposes only and no endorsement is implied. Equivalent performance may be achieved using apparatus and materials other than those specified here. Meeting the performance requirements of this method is the responsibility of the laboratory.


6.1 Sampling Equipment for Discrete or Composite Sampling


6.1.1 Sample bottles and caps


6.1.1.1 Liquid samples (waters, sludges and similar materials containing 5% solids or less)—Sample bottle, amber glass, 1.1 L minimum, with screw cap.


6.1.1.2 Solid samples (soils, sediments, sludges, paper pulps, filter cake, compost, and similar materials that contain more than 5% solids)—Sample bottle, wide mouth, amber glass, 500 mL minimum.


6.1.1.3 If amber bottles are not available, samples shall be protected from light.


6.1.1.4 Bottle caps—Threaded to fit sample bottles. Caps shall be lined with fluoropolymer.


6.1.1.5 Cleaning


6.1.1.5.1 Bottles are detergent water washed, then solvent rinsed before use.


6.1.1.5.2 Liners are detergent water washed, rinsed with reagent water (Section 7.6.1) followed by solvent, and baked at approximately 200 °C for a minimum of 1 hour prior to use.


6.1.2 Compositing equipment—Automatic or manual compositing system incorporating glass containers cleaned per bottle cleaning procedure above. Only glass or fluoropolymer tubing shall be used. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used in the pump only. Before use, the tubing shall be thoroughly rinsed with methanol, followed by repeated rinsing with reagent water to minimize sample contamination. An integrating flow meter is used to collect proportional composite samples.


6.2 Equipment for Glassware Cleaning—Laboratory sink with overhead fume hood.


6.3 Equipment for Sample Preparation


6.3.1 Laboratory fume hood of sufficient size to contain the sample preparation equipment listed below.


6.3.2 Glove box (optional).


6.3.3 Tissue homogenizer—VirTis Model 45 Macro homogenizer (American Scientific Products H-3515, or equivalent) with stainless steel Macro-shaft and Turbo-shear blade.


6.3.4 Meat grinder—Hobart, or equivalent, with 3-5 mm holes in inner plate.


6.3.5 Equipment for determining percent moisture


6.3.5.1 Oven—Capable of maintaining a temperature of 110 ±5 °C.


6.3.5.2 Dessicator.


6.3.6 Balances


6.3.6.1 Analytical—Capable of weighing 0.1 mg.


6.3.6.2 Top loading—Capable of weighing 10 mg.


6.4 Extraction Apparatus


6.4.1 Water samples


6.4.1.1 pH meter, with combination glass electrode.


6.4.1.2 pH paper, wide range (Hydrion Papers, or equivalent).


6.4.1.3 Graduated cylinder, 1 L capacity.


6.4.1.4 Liquid/liquid extraction—Separatory funnels, 250 mL, 500 mL, and 2000 mL, with fluoropolymer stopcocks.


6.4.1.5 Solid-phase extraction


6.4.1.5.1 One liter filtration apparatus, including glass funnel, glass frit support, clamp, adapter, stopper, filtration flask, and vacuum tubing (Figure 4). For wastewater samples, the apparatus should accept 90 or 144 mm disks. For drinking water or other samples containing low solids, smaller disks may be used.


6.4.1.5.2 Vacuum source capable of maintaining 25 in. Hg, equipped with shutoff valve and vacuum gauge.


6.4.1.5.3 Glass-fiber filter—Whatman GMF 150 (or equivalent), 1 micron pore size, to fit filtration apparatus in Section 6.4.1.5.1.


6.4.1.5.4 Solid-phase extraction disk containing octadecyl (C18) bonded silica uniformly enmeshed in an inert matrix—Fisher Scientific 14-378F (or equivalent), to fit filtration apparatus in Section 6.4.1.5.1.


6.4.2 Soxhlet/Dean-Stark (SDS) extractor (Figure 5)—For filters and solid/sludge samples.


6.4.2.1 Soxhlet—50 mm ID, 200 mL capacity with 500 mL flask (Cal-Glass LG-6900, or equivalent, except substitute 500 mL round-bottom flask for 300 mL flat-bottom flask).


6.4.2.2 Thimble—43 × 123 to fit Soxhlet (Cal-Glass LG-6901-122, or equivalent).


6.4.2.3 Moisture trap—Dean Stark or Barret with fluoropolymer stopcock, to fit Soxhlet.


6.4.2.4 Heating mantle—Hemispherical, to fit 500 mL round-bottom flask (Cal-Glass LG-8801-112, or equivalent).


6.4.2.5 Variable transformer—Powerstat (or equivalent), 110 volt, 10 amp.


6.4.3 Apparatus for extraction of tissue.


6.4.3.1 Bottle for extraction (if digestion/extraction using HCl is used)” 500-600 mL wide-mouth clear glass, with fluoropolymer-lined cap.


6.4.3.2 Bottle for back-extraction—100-200 mL narrow-mouth clear glass with fluoropolymer-lined cap.


6.4.3.3 Mechanical shaker—Wrist-action or platform-type rotary shaker that produces vigorous agitation (Sybron Thermolyne Model LE “Big Bill” rotator/shaker, or equivalent).


6.4.3.4 Rack attached to shaker table to permit agitation of four to nine samples simultaneously.


6.4.4 Beakers—400-500 mL.


6.4.5 Spatulas—Stainless steel.


6.5 Filtration Apparatus.


6.5.1 Pyrex glass wool—Solvent-extracted by SDS for three hours minimum.



Note:

Baking glass wool may cause active sites that will irreversibly adsorb CDDs/CDFs.


6.5.2 Glass funnel—125-250 mL.


6.5.3 Glass-fiber filter paper—Whatman GF/D (or equivalent), to fit glass funnel in Section 6.5.2.


6.5.4 Drying column—15-20 mm ID Pyrex chromatographic column equipped with coarse-glass frit or glass-wool plug.


6.5.5 Buchner funnel—15 cm.


6.5.6 Glass-fiber filter paper—to fit Buchner funnel in Section 6.5.5.


6.5.7 Filtration flasks—1.5-2.0 L, with side arm.


6.5.8 Pressure filtration apparatus—Millipore YT30 142 HW, or equivalent.


6.6 Centrifuge Apparatus.


6.6.1 Centrifuge—Capable of rotating 500 mL centrifuge bottles or 15 mL centrifuge tubes at 5,000 rpm minimum.


6.6.2 Centrifuge bottles—500 mL, with screw-caps, to fit centrifuge.


6.6.3 Centrifuge tubes—12-15 mL, with screw-caps, to fit centrifuge.


6.7 Cleanup Apparatus.


6.7.1 Automated gel permeation chromatograph (Analytical Biochemical Labs, Inc, Columbia, MO, Model GPC Autoprep 1002, or equivalent).


6.7.1.1 Column—600-700 mm long × 25 mm ID, packed with 70 g of


SX-3 Bio-beads (Bio-Rad Laboratories, Richmond, CA, or equivalent).

6.7.1.2 Syringe—10 mL, with Luer fitting.


6.7.1.3 Syringe filter holder—stainless steel, and glass-fiber or fluoropolymer filters (Gelman 4310, or equivalent).


6.7.1.4 UV detectors—254 nm, preparative or semi-preparative flow cell (Isco, Inc., Type 6; Schmadzu, 5 mm path length; Beckman-Altex 152W, 8 µL micro-prep flow cell, 2 mm path; Pharmacia UV-1, 3 mm flow cell; LDC Milton-Roy UV-3, monitor #1203; or equivalent).


6.7.2 Reverse-phase high-performance liquid chromatograph.


6.7.2.1 Column oven and detector—Perkin-Elmer Model LC-65T (or equivalent) operated at 0.02 AUFS at 235 nm.


6.7.2.2 Injector—Rheodyne 7120 (or equivalent) with 50 µL sample loop.


6.7.2.3 Column—Two 6.2 mm × 250 mm Zorbax-ODS columns in series (DuPont Instruments Division, Wilmington, DE, or equivalent), operated at 50 °C with 2.0 mL/min methanol isocratic effluent.


6.7.2.4 Pump—Altex 110A (or equivalent).


6.7.3 Pipets.


6.7.3.1 Disposable, pasteur—150 mm long × 5-mm ID (Fisher Scientific 13-678-6A, or equivalent).


6.7.3.2 Disposable, serological—10 mL (6 mm ID).


6.7.4 Glass chromatographic columns.


6.7.4.1 150 mm long × 8-mm ID, (Kontes K-420155, or equivalent) with coarse-glass frit or glass-wool plug and 250 mL reservoir.


6.7.4.2 200 mm long × 15 mm ID, with coarse-glass frit or glass-wool plug and 250 mL reservoir.


6.7.4.3 300 mm long × 25 mm ID, with 300 mL reservoir and glass or fluoropolymer stopcock.


6.7.5 Stirring apparatus for batch silica cleanup of tissue extracts.


6.7.5.1 Mechanical stirrer—Corning Model 320, or equivalent.


6.7.5.2 Bottle—500-600 mL wide-mouth clear glass.


6.7.6 Oven—For baking and storage of adsorbents, capable of maintaining a constant temperature (±5 °C) in the range of 105-250 °C.


6.8 Concentration Apparatus.


6.8.1 Rotary evaporator—Buchi/Brinkman-American Scientific No. E5045-10 or equivalent, equipped with a variable temperature water bath.


6.8.1.1 Vacuum source for rotary evaporator equipped with shutoff valve at the evaporator and vacuum gauge.


6.8.1.2 A recirculating water pump and chiller are recommended, as use of tap water for cooling the evaporator wastes large volumes of water and can lead to inconsistent performance as water temperatures and pressures vary.


6.8.1.3 Round-bottom flask—100 mL and 500 mL or larger, with ground-glass fitting compatible with the rotary evaporator.


6.8.2 Kuderna-Danish (K-D) Concentrator.


6.8.2.1 Concentrator tube—10 mL, graduated (Kontes K-570050-1025, or equivalent) with calibration verified. Ground-glass stopper (size 19/22 joint) is used to prevent evaporation of extracts.


6.8.2.2 Evaporation flask—500 mL (Kontes K-570001-0500, or equivalent), attached to concentrator tube with springs (Kontes K-662750-0012 or equivalent).


6.8.2.3 Snyder column—Three-ball macro (Kontes K-503000-0232, or equivalent).


6.8.2.4 Boiling chips.


6.8.2.4.1 Glass or silicon carbide—Approximately 10/40 mesh, extracted with methylene chloride and baked at 450 °C for one hour minimum.


6.8.2.4.2 Fluoropolymer (optional)—Extracted with methylene chloride.


6.8.2.5 Water bath—Heated, with concentric ring cover, capable of maintaining a temperature within ±2 °C, installed in a fume hood.


6.8.3 Nitrogen blowdown apparatus—Equipped with water bath controlled in the range of 30-60 °C (N-Evap, Organomation Associates, Inc., South Berlin, MA, or equivalent), installed in a fume hood.


6.8.4 Sample vials.


6.8.4.1 Amber glass—2-5 mL with fluoropolymer-lined screw-cap.


6.8.4.2 Glass—0.3 mL, conical, with fluoropolymer-lined screw or crimp cap.


6.9 Gas Chromatograph—Shall have splitless or on-column injection port for capillary column, temperature program with isothermal hold, and shall meet all of the performance specifications in Section 10.


6.9.1 GC column for CDDs/CDFs and for isomer specificity for 2,3,7,8-TCDD—60 ±5 m long × 0.32 ±0.02 mm ID; 0.25 µm 5% phenyl, 94% methyl, 1% vinyl silicone bonded-phase fused-silica capillary column (J&W DB-5, or equivalent).


6.9.2 GC column for isomer specificity for 2,3,7,8-TCDF—30 ±5 m long × 0.32 ±0.02 mm ID; 0.25 µm bonded-phase fused-silica capillary column (J&W DB-225, or equivalent).


6.10 Mass Spectrometer—28-40 eV electron impact ionization, shall be capable of repetitively selectively monitoring 12 exact m/z’s minimum at high resolution (≥10,000) during a period of approximately one second, and shall meet all of the performance specifications in Section 10.


6.11 GC/MS Interface—The mass spectrometer (MS) shall be interfaced to the GC such that the end of the capillary column terminates within 1 cm of the ion source but does not intercept the electron or ion beams.


6.12 Data System—Capable of collecting, recording, and storing MS data.


7.0 Reagents and Standards

7.1 pH Adjustment and Back-Extraction.


7.1.1 Potassium hydroxide—Dissolve 20 g reagent grade KOH in 100 mL reagent water.


7.1.2 Sulfuric acid—Reagent grade (specific gravity 1.84).


7.1.3 Hydrochloric acid—Reagent grade, 6N.


7.1.4 Sodium chloride—Reagent grade, prepare at 5% (w/v) solution in reagent water.


7.2 Solution Drying and Evaporation.


7.2.1 Solution drying—Sodium sulfate, reagent grade, granular, anhydrous (Baker 3375, or equivalent), rinsed with methylene chloride (20 mL/g), baked at 400 °C for one hour minimum, cooled in a dessicator, and stored in a pre-cleaned glass bottle with screw-cap that prevents moisture from entering. If, after heating, the sodium sulfate develops a noticeable grayish cast (due to the presence of carbon in the crystal matrix), that batch of reagent is not suitable for use and should be discarded. Extraction with methylene chloride (as opposed to simple rinsing) and baking at a lower temperature may produce sodium sulfate that is suitable for use.


7.2.2 Tissue drying—Sodium sulfate, reagent grade, powdered, treated and stored as above.


7.2.3 Prepurified nitrogen.


7.3 Extraction.


7.3.1 Solvents—Acetone, toluene, cyclohexane, hexane, methanol, methylene chloride, and nonane; distilled in glass, pesticide quality, lot-certified to be free of interferences.


7.3.2 White quartz sand, 60/70 mesh—For Soxhlet/Dean-Stark extraction (Aldrich Chemical, Cat. No. 27-437-9, or equivalent). Bake at 450 °C for four hours minimum.


7.4 GPC Calibration Solution—Prepare a solution containing 300 mg/mL corn oil, 15 mg/mL bis(2-ethylhexyl) phthalate, 1.4 mg/mL pentachlorophenol, 0.1 mg/mL perylene, and 0.5 mg/mL sulfur.


7.5 Adsorbents for Sample Cleanup.


7.5.1 Silica gel.


7.5.1.1 Activated silica gel—100-200 mesh, Supelco 1-3651 (or equivalent), rinsed with methylene chloride, baked at 180 °C for a minimum of one hour, cooled in a dessicator, and stored in a precleaned glass bottle with screw-cap that prevents moisture from entering.


7.5.1.2 Acid silica gel (30% w/w)—Thoroughly mix 44.0 g of concentrated sulfuric acid with 100.0 g of activated silica gel in a clean container. Break up aggregates with a stirring rod until a uniform mixture is obtained. Store in a bottle with a fluoropolymer-lined screw-cap.


7.5.1.3 Basic silica gel—Thoroughly mix 30 g of 1N sodium hydroxide with 100 g of activated silica gel in a clean container. Break up aggregates with a stirring rod until a uniform mixture is obtained. Store in a bottle with a fluoropolymer-lined screw-cap.


7.5.1.4 Potassium silicate.


7.5.1.4.1 Dissolve 56 g of high purity potassium hydroxide (Aldrich, or equivalent) in 300 mL of methanol in a 750-1000 mL flat-bottom flask.


7.5.1.4.2 Add 100 g of silica gel and a stirring bar, and stir on a hot plate at 60-70 °C for one to two hours.


7.5.1.4.3 Decant the liquid and rinse the potassium silicate twice with 100 mL portions of methanol, followed by a single rinse with 100 mL of methylene chloride.


7.5.1.4.4 Spread the potassium silicate on solvent-rinsed aluminum foil and dry for two to four hours in a hood.


7.5.1.4.5 Activate overnight at 200-250 °C.


7.5.2 Alumina—Either one of two types of alumina, acid or basic, may be used in the cleanup of sample extracts, provided that the laboratory can meet the performance specifications for the recovery of labeled compounds described in Section 9.3. The same type of alumina must be used for all samples, including those used to demonstrate initial precision and recovery (Section 9.2) and ongoing precision and recovery (Section 15.5).


7.5.2.1 Acid alumina—Supelco 19996-6C (or equivalent). Activate by heating to 130 °C for a minimum of 12 hours.


7.5.2.2 Basic alumina—Supelco 19944-6C (or equivalent). Activate by heating to 600 °C for a minimum of 24 hours. Alternatively, activate by heating in a tube furnace at 650-700 °C under an air flow rate of approximately 400 cc/minute. Do not heat over 700 °C, as this can lead to reduced capacity for retaining the analytes. Store at 130 °C in a covered flask. Use within five days of baking.


7.5.3 Carbon.


7.5.3.1 Carbopak C—(Supelco 1-0258, or equivalent).


7.5.3.2 Celite 545—(Supelco 2-0199, or equivalent).


7.5.3.3 Thoroughly mix 9.0 g Carbopak C and 41.0 g Celite 545 to produce an 18% w/w mixture. Activate the mixture at 130 °C for a minimum of six hours. Store in a dessicator.


7.5.4 Anthropogenic isolation column—Pack the column in Section 6.7.4.3 from bottom to top with the following:


7.5.4.1 2 g silica gel (Section 7.5.1.1).


7.5.4.2 2 g potassium silicate (Section 7.5.1.4).


7.5.4.3 2 g granular anhydrous sodium sulfate (Section 7.2.1).


7.5.4.4 10 g acid silica gel (Section 7.5.1.2).


7.5.4.5 2 g granular anhydrous sodium sulfate.


7.5.5 Florisil column.


7.5.5.1 Florisil—60-100 mesh, Floridin Corp (or equivalent). Soxhlet extract in 500 g portions for 24 hours.


7.5.5.2 Insert a glass wool plug into the tapered end of a graduated serological pipet (Section 6.7.3.2). Pack with 1.5 g (approx 2 mL) of Florisil topped with approx 1 mL of sodium sulfate (Section 7.2.1) and a glass wool plug.


7.5.5.3 Activate in an oven at 130-150 °C for a minimum of 24 hours and cool for 30 minutes. Use within 90 minutes of cooling.


7.6 Reference Matrices—Matrices in which the CDDs/CDFs and interfering compounds are not detected by this method.


7.6.1 Reagent water—Bottled water purchased locally, or prepared by passage through activated carbon.


7.6.2 High-solids reference matrix—Playground sand or similar material. Prepared by extraction with methylene chloride and/or baking at 450 °C for a minimum of four hours.


7.6.3 Paper reference matrix—Glass-fiber filter, Gelman Type A, or equivalent. Cut paper to simulate the surface area of the paper sample being tested.


7.6.4 Tissue reference matrix—Corn or other vegetable oil. May be prepared by extraction with methylene chloride.


7.6.5 Other matrices—This method may be verified on any reference matrix by performing the tests given in Section 9.2. Ideally, the matrix should be free of the CDDs/CDFs, but in no case shall the background level of the CDDs/CDFs in the reference matrix exceed three times the minimum levels in Table 2. If low background levels of the CDDs/CDFs are present in the reference matrix, the spike level of the analytes used in Section 9.2 should be increased to provide a spike-to-background ratio in the range of 1:1 to 5:1 (Reference 15).


7.7 Standard Solutions—Purchased as solutions or mixtures with certification to their purity, concentration, and authenticity, or prepared from materials of known purity and composition. If the chemical purity is 98% or greater, the weight may be used without correction to compute the concentration of the standard. When not being used, standards are stored in the dark at room temperature in screw-capped vials with fluoropolymer-lined caps. A mark is placed on the vial at the level of the solution so that solvent loss by evaporation can be detected. If solvent loss has occurred, the solution should be replaced.


7.8 Stock Solutions.


7.8.1 Preparation—Prepare in nonane per the steps below or purchase as dilute solutions (Cambridge Isotope Laboratories (CIL), Woburn, MA, or equivalent). Observe the safety precautions in Section 5, and the recommendation in Section 5.1.2.


7.8.2 Dissolve an appropriate amount of assayed reference material in solvent. For example, weigh 1-2 mg of 2,3,7,8-TCDD to three significant figures in a 10 mL ground-glass-stoppered volumetric flask and fill to the mark with nonane. After the TCDD is completely dissolved, transfer the solution to a clean 15 mL vial with fluoropolymer-lined cap.


7.8.3 Stock standard solutions should be checked for signs of degradation prior to the preparation of calibration or performance test standards. Reference standards that can be used to determine the accuracy of calibration standards are available from CIL and may be available from other vendors.


7.9 PAR Stock Solution


7.9.1 All CDDs/CDFs—Using the solutions in Section 7.8, prepare the PAR stock solution to contain the CDDs/CDFs at the concentrations shown in Table 3. When diluted, the solution will become the PAR (Section 7.14).


7.9.2 If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, prepare the PAR stock solution to contain these compounds only.


7.10 Labeled-Compound Spiking Solution.


7.10.1 All CDDs/CDFs—From stock solutions, or from purchased mixtures, prepare this solution to contain the labeled compounds in nonane at the concentrations shown in Table 3. This solution is diluted with acetone prior to use (Section 7.10.3).


7.10.2 If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, prepare the labeled-compound solution to contain these compounds only. This solution is diluted with acetone prior to use (Section 7.10.3).


7.10.3 Dilute a sufficient volume of the labeled compound solution (Section 7.10.1 or 7.10.2) by a factor of 50 with acetone to prepare a diluted spiking solution. Each sample requires 1.0 mL of the diluted solution, but no more solution should be prepared than can be used in one day.


7.11 Cleanup Standard—Prepare
37Cl
4-2,3,7,8-TCDD in nonane at the concentration shown in Table 3. The cleanup standard is added to all extracts prior to cleanup to measure the efficiency of the cleanup process.


7.12 Internal Standard(s).


7.12.1 All CDDs/CDFs—Prepare the internal standard solution to contain
13C
12-1,2,3,4-TCDD and
13C
2-1,2,3,7,8,9-HxCDD in nonane at the concentration shown in Table 3.


7.12.2 If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, prepare the internal standard solution to contain
13C
12-1,2,3,4-TCDD only.


7.13 Calibration Standards (CS1 through CS5)—Combine the solutions in Sections 7.9 through 7.12 to produce the five calibration solutions shown in Table 4 in nonane. These solutions permit the relative response (labeled to native) and response factor to be measured as a function of concentration. The CS3 standard is used for calibration verification (VER). If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, combine the solutions appropriate to these compounds.


7.14 Precision and Recovery (PAR) Standard—Used for determination of initial (Section 9.2) and ongoing (Section 15.5) precision and recovery. Dilute 10 µL of the precision and recovery standard (Section 7.9.1 or 7.9.2) to 2.0 mL with acetone for each sample matrix for each sample batch. One mL each are required for the blank and OPR with each matrix in each batch.


7.15 GC Retention Time Window Defining Solution and Isomer Specificity Test Standard—Used to define the beginning and ending retention times for the dioxin and furan isomers and to demonstrate isomer specificity of the GC columns employed for determination of 2,3,7,8-TCDD and 2,3,7,8-TCDF. The standard must contain the compounds listed in Table 5 (CIL EDF—4006, or equivalent), at a minimum. It is not necessary to monitor the window-defining compounds if only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined. In this case, an isomer-specificity test standard containing the most closely eluted isomers listed in Table 5 (CIL EDF-4033, or equivalent) may be used.


7.16 QC Check Sample—A QC Check Sample should be obtained from a source independent of the calibration standards. Ideally, this check sample would be a certified reference material containing the CDDs/CDFs in known concentrations in a sample matrix similar to the matrix under test.


7.17 Stability of Solutions—Standard solutions used for quantitative purposes (Sections 7.9 through 7.15) should be analyzed periodically, and should be assayed against reference standards (Section 7.8.3) before further use.


8.0 Sample Collection, Preservation, Storage, and Holding Times

8.1 Collect samples in amber glass containers following conventional sampling practices (Reference 16). Aqueous samples that flow freely are collected in refrigerated bottles using automatic sampling equipment. Solid samples are collected as grab samples using wide-mouth jars.


8.2 Maintain aqueous samples in the dark at 0-4 °C from the time of collection until receipt at the laboratory. If residual chlorine is present in aqueous samples, add 80 mg sodium thiosulfate per liter of water. EPA Methods 330.4 and 330.5 may be used to measure residual chlorine (Reference 17). If sample pH is greater than 9, adjust to pH 7-9 with sulfuric acid.


Maintain solid, semi-solid, oily, and mixed-phase samples in the dark at

Store aqueous samples in the dark at 0-4 °C. Store solid, semi-solid, oily, mixed-phase, and tissue samples in the dark at

8.3 Fish and Tissue Samples.


8.3.1 Fish may be cleaned, filleted, or processed in other ways in the field, such that the laboratory may expect to receive whole fish, fish fillets, or other tissues for analysis.


8.3.2 Fish collected in the field should be wrapped in aluminum foil, and must be maintained at a temperature less than 4 °C from the time of collection until receipt at the laboratory.


8.3.3 Samples must be frozen upon receipt at the laboratory and maintained in the dark at

8.4 Holding Times.


8.4.1 There are no demonstrated maximum holding times associated with CDDs/CDFs in aqueous, solid, semi-solid, tissues, or other sample matrices. If stored in the dark at 0-4 °C and preserved as given above (if required), aqueous samples may be stored for up to one year. Similarly, if stored in the dark at

8.4.2 Store sample extracts in the dark at
9.0 Quality Assurance/Quality Control

9.1 Each laboratory that uses this method is required to operate a formal quality assurance program (Reference 18). The minimum requirements of this program consist of an initial demonstration of laboratory capability, analysis of samples spiked with labeled compounds to evaluate and document data quality, and analysis of standards and blanks as tests of continued performance. Laboratory performance is compared to established performance criteria to determine if the results of analyses meet the performance characteristics of the method.


If the method is to be applied to sample matrix other than water (e.g., soils, filter cake, compost, tissue) the most appropriate alternate matrix (Sections 7.6.2 through 7.6.5) is substituted for the reagent water matrix (Section 7.6.1) in all performance tests.


9.1.1 The analyst shall make an initial demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 9.2.


9.1.2 In recognition of advances that are occurring in analytical technology, and to allow the analyst to overcome sample matrix interferences, the analyst is permitted certain options to improve separations or lower the costs of measurements. These options include alternate extraction, concentration, cleanup procedures, and changes in columns and detectors. Alternate determinative techniques, such as the substitution of spectroscopic or immuno-assay techniques, and changes that degrade method performance, are not allowed. If an analytical technique other than the techniques specified in this method is used, that technique must have a specificity equal to or better than the specificity of the techniques in this method for the analytes of interest.


9.1.2.1 Each time a modification is made to this method, the analyst is required to repeat the procedure in Section 9.2. If the detection limit of the method will be affected by the change, the laboratory is required to demonstrate that the MDL (40 CFR part 136, appendix B) is lower than one-third the regulatory compliance level or one-third the ML in this method, whichever is higher. If calibration will be affected by the change, the analyst must recalibrate the instrument per Section 10.


9.1.2.2 The laboratory is required to maintain records of modifications made to this method. These records include the following, at a minimum:


9.1.2.2.1 The names, titles, addresses, and telephone numbers of the analyst(s) who performed the analyses and modification, and of the quality control officer who witnessed and will verify the analyses and modifications.


9.1.2.2.2 A listing of pollutant(s) measured, by name and CAS Registry number.


9.1.2.2.3 A narrative stating reason(s) for the modifications.


9.1.2.2.4 Results from all quality control (QC) tests comparing the modified method to this method, including:


(a) Calibration (Section 10.5 through 10.7).


(b) Calibration verification (Section 15.3).


(c) Initial precision and recovery (Section 9.2).


(d) Labeled compound recovery (Section 9.3).


(e) Analysis of blanks (Section 9.5).


(f) Accuracy assessment (Section 9.4).


9.1.2.2.5 Data that will allow an independent reviewer to validate each determination by tracing the instrument output (peak height, area, or other signal) to the final result. These data are to include:


(a) Sample numbers and other identifiers.


(b) Extraction dates.


(c) Analysis dates and times.


(d) Analysis sequence/run chronology.


(e) Sample weight or volume (Section 11).


(f) Extract volume prior to each cleanup step (Section 13).


(g) Extract volume after each cleanup step (Section 13).


(h) Final extract volume prior to injection (Section 14).


(i) Injection volume (Section 14.3).


(j) Dilution data, differentiating between dilution of a sample or extract (Section 17.5).


(k) Instrument and operating conditions.


(l) Column (dimensions, liquid phase, solid support, film thickness, etc).


(m) Operating conditions (temperatures, temperature program, flow rates).


(n) Detector (type, operating conditions, etc).


(o) Chromatograms, printer tapes, and other recordings of raw data.


(p) Quantitation reports, data system outputs, and other data to link the raw data to the results reported.


9.1.3 Analyses of method blanks are required to demonstrate freedom from contamination (Section 4.3). The procedures and criteria for analysis of a method blank are described in Sections 9.5 and 15.6.


9.1.4 The laboratory shall spike all samples with labeled compounds to monitor method performance. This test is described in Section 9.3. When results of these spikes indicate atypical method performance for samples, the samples are diluted to bring method performance within acceptable limits. Procedures for dilution are given in Section 17.5.


9.1.5 The laboratory shall, on an ongoing basis, demonstrate through calibration verification and the analysis of the ongoing precision and recovery aliquot that the analytical system is in control. These procedures are described in Sections 15.1 through 15.5.


9.1.6 The laboratory shall maintain records to define the quality of data that is generated. Development of accuracy statements is described in Section 9.4.


9.2 Initial Precision and Recovery (IPR)—To establish the ability to generate acceptable precision and recovery, the analyst shall perform the following operations.


9.2.1 For low solids (aqueous) samples, extract, concentrate, and analyze four 1 L aliquots of reagent water spiked with the diluted labeled compound spiking solution (Section 7.10.3) and the precision and recovery standard (Section 7.14) according to the procedures in Sections 11 through 18. For an alternative sample matrix, four aliquots of the alternative reference matrix (Section 7.6) are used. All sample processing steps that are to be used for processing samples, including preparation (Section 11), extraction (Section 12), and cleanup (Section 13), shall be included in this test.


9.2.2 Using results of the set of four analyses, compute the average concentration (X) of the extracts in ng/mL and the standard deviation of the concentration (s) in ng/mL for each compound, by isotope dilution for CDDs/CDFs with a labeled analog, and by internal standard for 1,2,3,7,8,9-HxCDD, OCDF, and the labeled compounds.


9.2.3 For each CDD/CDF and labeled compound, compare s and X with the corresponding limits for initial precision and recovery in Table 6. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, compare s and X with the corresponding limits for initial precision and recovery in Table 6a. If s and X for all compounds meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may begin. If, however, any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, system performance is unacceptable for that compound. Correct the problem and repeat the test (Section 9.2).


9.3 The laboratory shall spike all samples with the diluted labeled compound spiking solution (Section 7.10.3) to assess method performance on the sample matrix.


9.3.1 Analyze each sample according to the procedures in Sections 11 through 18.


9.3.2 Compute the percent recovery of the labeled compounds and the cleanup standard using the internal standard method (Section 17.2).


9.3.3 The recovery of each labeled compound must be within the limits in Table 7 when all 2,3,7,8-substituted CDDs/CDFs are determined, and within the limits in Table 7a when only 2,3,7,8-TCDD and 2,3,7,8-TCDF are determined. If the recovery of any compound falls outside of these limits, method performance is unacceptable for that compound in that sample. To overcome such difficulties, water samples are diluted and smaller amounts of soils, sludges, sediments, and other matrices are reanalyzed per Section 18.4.


9.4 Recovery of labeled compounds from samples should be assessed and records should be maintained.


9.4.1 After the analysis of five samples of a given matrix type (water, soil, sludge, pulp, etc.) for which the labeled compounds pass the tests in Section 9.3, compute the average percent recovery (R) and the standard deviation of the percent recovery (SR) for the labeled compounds only. Express the assessment as a percent recovery interval from R−2SR to R = 2SR for each matrix. For example, if R = 90% and SR = 10% for five analyses of pulp, the recovery interval is expressed as 70-110%.


9.4.2 Update the accuracy assessment for each labeled compound in each matrix on a regular basis (e.g., after each 5-10 new measurements).


9.5 Method Blanks—Reference matrix method blanks are analyzed to demonstrate freedom from contamination (Section 4.3).


9.5.1 Prepare, extract, clean up, and concentrate a method blank with each sample batch (samples of the same matrix started through the extraction process on the same 12-hour shift, to a maximum of 20 samples). The matrix for the method blank shall be similar to sample matrix for the batch, e.g., a 1 L reagent water blank (Section 7.6.1), high-solids reference matrix blank (Section 7.6.2), paper matrix blank (Section 7.6.3); tissue blank (Section 7.6.4) or alternative reference matrix blank (Section 7.6.5). Analyze the blank immediately after analysis of the OPR (Section 15.5) to demonstrate freedom from contamination.


9.5.2 If any 2,3,7,8-substituted CDD/CDF (Table 1) is found in the blank at greater than the minimum level (Table 2) or one-third the regulatory compliance level, whichever is greater; or if any potentially interfering compound is found in the blank at the minimum level for each level of chlorination given in Table 2 (assuming a response factor of 1 relative to the
13C12-1,2,3,4-TCDD internal standard for compounds not listed in Table 1), analysis of samples is halted until the blank associated with the sample batch shows no evidence of contamination at this level. All samples must be associated with an uncontaminated method blank before the results for those samples may be reported for regulatory compliance purposes.


9.6 QC Check Sample—Analyze the QC Check Sample (Section 7.16) periodically to assure the accuracy of calibration standards and the overall reliability of the analytical process. It is suggested that the QC Check Sample be analyzed at least quarterly.


9.7 The specifications contained in this method can be met if the apparatus used is calibrated properly and then maintained in a calibrated state. The standards used for calibration (Section 10), calibration verification (Section 15.3), and for initial (Section 9.2) and ongoing (Section 15.5) precision and recovery should be identical, so that the most precise results will be obtained. A GC/MS instrument will provide the most reproducible results if dedicated to the settings and conditions required for the analyses of CDDs/CDFs by this method.


9.8 Depending on specific program requirements, field replicates may be collected to determine the precision of the sampling technique, and spiked samples may be required to determine the accuracy of the analysis when the internal standard method is used.


10.0 Calibration

10.1 Establish the operating conditions necessary to meet the minimum retention times for the internal standards in Section 10.2.4 and the relative retention times for the CDDs/CDFs in Table 2.


10.1.1 Suggested GC operating conditions:


Injector temperature: 270 °C

Interface temperature: 290 °C

Initial temperature: 200 °C

Initial time: Two minutes

Temperature program:

200-220 °C, at 5 °C/minute

220 °C for 16 minutes

220-235 °C, at 5 °C/minute

235 °C for seven minutes

235-330 °C, at 5 °C/minute


Note:

All portions of the column that connect the GC to the ion source shall remain at or above the interface temperature specified above during analysis to preclude condensation of less volatile compounds.


Optimize GC conditions for compound separation and sensitivity. Once optimized, the same GC conditions must be used for the analysis of all standards, blanks, IPR and OPR aliquots, and samples.


10.1.2 Mass spectrometer (MS) resolution—Obtain a selected ion current profile (SICP) of each analyte in Table 3 at the two exact m/z’s specified in Table 8 and at ≥10,000 resolving power by injecting an authentic standard of the CDDs/CDFs either singly or as part of a mixture in which there is no interference between closely eluted components.


10.1.2.1 The analysis time for CDDs/CDFs may exceed the long-term mass stability of the mass spectrometer. Because the instrument is operated in the high-resolution mode, mass drifts of a few ppm (e.g., 5 ppm in mass) can have serious adverse effects on instrument performance. Therefore, a mass-drift correction is mandatory and a lock-mass m/z from PFK is used for drift correction. The lock-mass m/z is dependent on the exact m/z’s monitored within each descriptor, as shown in Table 8. The level of PFK metered into the HRMS during analyses should be adjusted so that the amplitude of the most intense selected lock-mass m/z signal (regardless of the descriptor number) does not exceed 10% of the full-scale deflection for a given set of detector parameters. Under those conditions, sensitivity changes that might occur during the analysis can be more effectively monitored.



Note:

Excessive PFK (or any other reference substance) may cause noise problems and contamination of the ion source necessitating increased frequency of source cleaning.


10.1.2.2 If the HRMS has the capability to monitor resolution during the analysis, it is acceptable to terminate the analysis when the resolution falls below 10,000 to save reanalysis time.


10.1.2.3 Using a PFK molecular leak, tune the instrument to meet the minimum required resolving power of 10,000 (10% valley) at m/z 304.9824 (PFK) or any other reference signal close to m/z 304 (from TCDF). For each descriptor (Table 8), monitor and record the resolution and exact m/z’s of three to five reference peaks covering the mass range of the descriptor. The resolution must be greater than or equal to 10,000, and the deviation between the exact m/z and the theoretical m/z (Table 8) for each exact m/z monitored must be less than 5 ppm.


10.2 Ion Abundance Ratios, Minimum Levels, Signal-to-Noise Ratios, and Absolute Retention Times—Choose an injection volume of either 1 µL or 2 µL, consistent with the capability of the HRGC/HRMS instrument. Inject a 1 µL or 2 µL aliquot of the CS1 calibration solution (Table 4) using the GC conditions from Section 10.1.1. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, the operating conditions and specifications below apply to analysis of those compounds only.


10.2.1 Measure the SICP areas for each analyte, and compute the ion abundance ratios at the exact m/z’s specified in Table 8. Compare the computed ratio to the theoretical ratio given in Table 9.


10.2.1.1 The exact m/z’s to be monitored in each descriptor are shown in Table 8. Each group or descriptor shall be monitored in succession as a function of GC retention time to ensure that all CDDs/CDFs are detected. Additional m/z’s may be monitored in each descriptor, and the m/z’s may be divided among more than the five descriptors listed in Table 8, provided that the laboratory is able to monitor the m/z’s of all the CDDs/CDFs that may elute from the GC in a given retention-time window. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, the descriptors may be modified to include only the exact m/z’s for the tetra-and penta-isomers, the diphenyl ethers, and the lock m/z’s.


10.2.1.2 The mass spectrometer shall be operated in a mass-drift correction mode, using perfluorokerosene (PFK) to provide lock m/z’s. The lock-mass for each group of m/z’s is shown in Table 8. Each lock mass shall be monitored and shall not vary by more than ±20% throughout its respective retention time window. Variations of the lock mass by more than 20% indicate the presence of coeluting interferences that may significantly reduce the sensitivity of the mass spectrometer. Reinjection of another aliquot of the sample extract will not resolve the problem. Additional cleanup of the extract may be required to remove the interferences.


10.2.2 All CDDs/CDFs and labeled compounds in the CS1 standard shall be within the QC limits in Table 9 for their respective ion abundance ratios; otherwise, the mass spectrometer shall be adjusted and this test repeated until the m/z ratios fall within the limits specified. If the adjustment alters the resolution of the mass spectrometer, resolution shall be verified (Section 10.1.2) prior to repeat of the test.


10.2.3 Verify that the HRGC/HRMS instrument meets the minimum levels in Table 2. The peaks representing the CDDs/CDFs and labeled compounds in the CS1 calibration standard must have signal-to-noise ratios (S/N) greater than or equal to 10.0. Otherwise, the mass spectrometer shall be adjusted and this test repeated until the minimum levels in Table 2 are met.


10.2.4 The absolute retention time of
13C12-1,2,3,4-TCDD (Section 7.12) shall exceed 25.0 minutes on the DB-5 column, and the retention time of
13C12-1,2,3,4-TCDD shall exceed 15.0 minutes on the DB-225 column; otherwise, the GC temperature program shall be adjusted and this test repeated until the above-stated minimum retention time criteria are met.


2010.3 Retention-Time Windows—Analyze the window defining mixtures (Section 7.15) using the optimized temperature program in Section 10.1. Table 5 gives the elution order (first/last) of the window-defining compounds. If 2,3,7,8-TCDD and 2,3,7,8-TCDF only are to be analyzed, this test is not required.

10.4 Isomer Specificity.


10.4.1 Analyze the isomer specificity test standards (Section 7.15) using the procedure in Section 14 and the optimized conditions for sample analysis (Section 10.1.1).


10.4.2 Compute the percent valley between the GC peaks that elute most closely to the 2,3,7,8-TCDD and TCDF isomers, on their respective columns, per Figures 6 and 7.


10.4.3 Verify that the height of the valley between the most closely eluted isomers and the 2,3,7,8-substituted isomers is less than 25% (computed as 100 x/y in Figures 6 and 7). If the valley exceeds 25%, adjust the analytical conditions and repeat the test or replace the GC column and recalibrate (Sections 10.1.2 through 10.7).


10.5 Calibration by Isotope Dilution—Isotope dilution calibration is used for the 15 2,3,7,8-substituted CDDs/CDFs for which labeled compounds are added to samples prior to extraction. The reference compound for each CDD/CDF compound is shown in Table 2.


10.5.1 A calibration curve encompassing the concentration range is prepared for each compound to be determined. The relative response (RR) (labeled to native) vs. concentration in standard solutions is plotted or computed using a linear regression. Relative response is determined according to the procedures described below. Five calibration points are employed.


10.5.2 The response of each CDD/CDF relative to its labeled analog is determined using the area responses of both the primary and secondary exact m/z’s specified in Table 8, for each calibration standard, as follows:



where:

A1n and A2n = The areas of the primary and secondary m/z’s for the CDD/CDF.

A1l and A2l = The areas of the primary and secondary m/z’s for the labeled compound.

Cl = The concentration of the labeled compound in the calibration standard (Table 4).

Cn = The concentration of the native compound in the calibration standard (Table 4).

10.5.3 To calibrate the analytical system by isotope dilution, inject a volume of calibration standards CS1 through CS5 (Section 7.13 and Table 4) identical to the volume chosen in Section 10.2, using the procedure in Section 14 and the conditions in Section 10.1.1 and Table 2. Compute the relative response (RR) at each concentration.


10.5.4 Linearity—If the relative response for any compound is constant (less than 20% coefficient of variation) over the five-point calibration range, an averaged relative response may be used for that compound; otherwise, the complete calibration curve for that compound shall be used over the five-point calibration range.


10.6 Calibration by Internal Standard—The internal standard method is applied to determination of 1,2,3,7,8,9-HxCDD (Section 17.1.2), OCDF (Section 17.1.1), the non 2,3,7,8-substituted compounds, and to the determination of labeled compounds for intralaboratory statistics (Sections 9.4 and 15.5.4).


10.6.1 Response factors—Calibration requires the determination of response factors (RF) defined by the following equation:



where:

A1s and A2s = The areas of the primary and secondary m/z’s for the CDD/CDF.

A1is and A2is = The areas of the primary and secondary m/z’s for the internal standard.

Cis = The concentration of the internal standard (Table 4).

Cs = The concentration of the compound in the calibration standard (Table 4).


Note:

There is only one m/z for
37Cl4-2,3,7,8-TCDD. See Table 8.


10.6.2 To calibrate the analytical system by internal standard, inject 1.0 µL or 2.0 µL of calibration standards CS1 through CS5 (Section 7.13 and Table 4) using the procedure in Section 14 and the conditions in Section 10.1.1 and Table 2. Compute the response factor (RF) at each concentration.


10.6.3 Linearity—If the response factor (RF) for any compound is constant (less than 35% coefficient of variation) over the five-point calibration range, an averaged response factor may be used for that compound; otherwise, the complete calibration curve for that compound shall be used over the five-point range.


10.7 Combined Calibration—By using calibration solutions (Section 7.13 and Table 4) containing the CDDs/CDFs and labeled compounds and the internal standards, a single set of analyses can be used to produce calibration curves for the isotope dilution and internal standard methods. These curves are verified each shift (Section 15.3) by analyzing the calibration verification standard (VER, Table 4). Recalibration is required if any of the calibration verification criteria (Section 15.3) cannot be met.


10.8 Data Storage—MS data shall be collected, recorded, and stored.


10.8.1 Data acquisition—The signal at each exact m/z shall be collected repetitively throughout the monitoring period and stored on a mass storage device.


10.8.2 Response factors and multipoint calibrations—The data system shall be used to record and maintain lists of response factors (response ratios for isotope dilution) and multipoint calibration curves. Computations of relative standard deviation (coefficient of variation) shall be used to test calibration linearity. Statistics on initial performance (Section 9.2) and ongoing performance (Section 15.5) should be computed and maintained, either on the instrument data system, or on a separate computer system.


11.0 Sample Preparation

11.1 Sample preparation involves modifying the physical form of the sample so that the CDDs/CDFs can be extracted efficiently. In general, the samples must be in a liquid form or in the form of finely divided solids in order for efficient extraction to take place. Table 10 lists the phases and suggested quantities for extraction of various sample matrices.


For samples known or expected to contain high levels of the CDDs/CDFs, the smallest sample size representative of the entire sample should be used (see Section 17.5).


For all samples, the blank and IPR/OPR aliquots must be processed through the same steps as the sample to check for contamination and losses in the preparation processes.


11.1.1 For samples that contain particles, percent solids and particle size are determined using the procedures in Sections 11.2 and 11.3, respectively.


11.1.2 Aqueous samples—Because CDDs/CDFs may be bound to suspended particles, the preparation of aqueous samples is dependent on the solids content of the sample.


11.1.2.1 Aqueous samples visibly absent particles are prepared per Section 11.4 and extracted directly using the separatory funnel or SPE techniques in Sections 12.1 or 12.2, respectively.


11.1.2.2 Aqueous samples containing visible particles and containing one percent suspended solids or less are prepared using the procedure in Section 11.4. After preparation, the sample is extracted directly using the SPE technique in 12.2 or filtered per Section 11.4.3. After filtration, the particles and filter are extracted using the SDS procedure in Section 12.3 and the filtrate is extracted using the separatory funnel procedure in Section 12.1.


11.1.2.3 For aqueous samples containing greater than one percent solids, a sample aliquot sufficient to provide 10 g of dry solids is used, as described in Section 11.5.


11.1.3 Solid samples are prepared using the procedure described in Section 11.5 followed by extraction via the SDS procedure in Section 12.3.


11.1.4 Multiphase samples—The phase(s) containing the CDDs/CDFs is separated from the non-CDD/CDF phase using pressure filtration and centrifugation, as described in Section 11.6. The CDDs/CDFs will be in the organic phase in a multiphase sample in which an organic phase exists.


11.1.5 Procedures for grinding, homogenization, and blending of various sample phases are given in Section 11.7.


11.1.6 Tissue samples—Preparation procedures for fish and other tissues are given in Section 11.8.


11.2 Determination of Percent Suspended Solids.



Note:

This aliquot is used for determining the solids content of the sample, not for determination of CDDs/CDFs.


11.2.1 Aqueous liquids and multi-phase samples consisting of mainly an aqueous phase.


11.2.1.1 Dessicate and weigh a GF/D filter (Section 6.5.3) to three significant figures.


11.2.1.2 Filter 10.0 ±0.02 mL of well-mixed sample through the filter.


11.2.1.3 Dry the filter a minimum of 12 hours at 110 ±5 °C and cool in a dessicator.


11.2.1.4 Calculate percent solids as follows:



11.2.2 Non-aqueous liquids, solids, semi-solid samples, and multi-phase samples in which the main phase is not aqueous; but not tissues.


11.2.2.1 Weigh 5-10 g of sample to three significant figures in a tared beaker.


11.2.2.2 Dry a minimum of 12 hours at 110 ±5 °C, and cool in a dessicator.


11.2.2.3 Calculate percent solids as follows:



11.3 Determination of Particle Size.


11.3.1 Spread the dried sample from Section 11.2.2.2 on a piece of filter paper or aluminum foil in a fume hood or glove box.


11.3.2 Estimate the size of the particles in the sample. If the size of the largest particles is greater than 1 mm, the particle size must be reduced to 1 mm or less prior to extraction using the procedures in Section 11.7.


11.4 Preparation of Aqueous Samples Containing 1% Suspended Solids or Less.


11.4.1 Aqueous samples visibly absent particles are prepared per the procedure below and extracted directly using the separatory funnel or SPE techniques in Sections 12.1 or 12.2, respectively. Aqueous samples containing visible particles and one percent suspended solids or less are prepared using the procedure below and extracted using either the SPE technique in Section 12.2 or further prepared using the filtration procedure in Section 11.4.3. The filtration procedure is followed by SDS extraction of the filter and particles (Section 12.3) and separatory funnel extraction of the filtrate (Section 12.1). The SPE procedure is followed by SDS extraction of the filter and disk.


11.4.2 Preparation of sample and QC aliquots.


11.4.2.1 Mark the original level of the sample on the sample bottle for reference. Weigh the sample plus bottle to ±1.


11.4.2.2 Spike 1.0 mL of the diluted labeled-compound spiking solution (Section 7.10.3) into the sample bottle. Cap the bottle and mix the sample by careful shaking. Allow the sample to equilibrate for one to two hours, with occasional shaking.


11.4.2.3 For each sample or sample batch (to a maximum of 20 samples) to be extracted during the same 12-hour shift, place two 1.0 L aliquots of reagent water in clean sample bottles or flasks.


11.4.2.4 Spike 1.0 mL of the diluted labeled-compound spiking solution (Section 7.10.3) into both reagent water aliquots. One of these aliquots will serve as the method blank.


11.4.2.5 Spike 1.0 mL of the PAR standard (Section 7.14) into the remaining reagent water aliquot. This aliquot will serve as the OPR (Section 15.5).


11.4.2.6 If SPE is to be used, add 5 mL of methanol to the sample, cap and shake the sample to mix thoroughly, and proceed to Section 12.2 for extraction. If SPE is not to be used, and the sample is visibly absent particles, proceed to Section 12.1 for extraction. If SPE is not to be used and the sample contains visible particles, proceed to the following section for filtration of particles.


11.4.3 Filtration of particles.


11.4.3.1 Assemble a Buchner funnel (Section 6.5.5) on top of a clean filtration flask. Apply vacuum to the flask, and pour the entire contents of the sample bottle through a glass-fiber filter (Section 6.5.6) in the Buchner funnel, swirling the sample remaining in the bottle to suspend any particles.


11.4.3.2 Rinse the sample bottle twice with approximately 5 mL portions of reagent water to transfer any remaining particles onto the filter.


11.4.3.3 Rinse any particles off the sides of the Buchner funnel with small quantities of reagent water.


11.4.3.4 Weigh the empty sample bottle to ±1 g. Determine the weight of the sample by difference. Save the bottle for further use.


11.4.3.5 Extract the filtrate using the separatory funnel procedure in Section 12.1.


11.4.3.6 Extract the filter containing the particles using the SDS procedure in Section 12.3.


11.5 Preparation of Samples Containing Greater Than 1% Solids.


11.5.1 Weigh a well-mixed aliquot of each sample (of the same matrix type) sufficient to provide 10 g of dry solids (based on the solids determination in Section 11.2) into a clean beaker or glass jar.


11.5.2 Spike 1.0 mL of the diluted labeled compound spiking solution (Section 7.10.3) into the sample.


11.5.3 For each sample or sample batch (to a maximum of 20 samples) to be extracted during the same 12-hour shift, weigh two 10 g aliquots of the appropriate reference matrix (Section 7.6) into clean beakers or glass jars.


11.5.4 Spike 1.0 mL of the diluted labeled compound spiking solution (Section 7.10.3) into each reference matrix aliquot. One aliquot will serve as the method blank. Spike 1.0 mL of the PAR standard (Section 7.14) into the other reference matrix aliquot. This aliquot will serve as the OPR (Section 15.5).


11.5.5 Stir or tumble and equilibrate the aliquots for one to two hours.


11.5.6 Decant excess water. If necessary to remove water, filter the sample through a glass-fiber filter and discard the aqueous liquid.


11.5.7 If particles >1mm are present in the sample (as determined in Section 11.3.2), spread the sample on clean aluminum foil in a hood. After the sample is dry, grind to reduce the particle size (Section 11.7).


11.5.8 Extract the sample and QC aliquots using the SDS procedure in Section 12.3.


11.6 Multiphase Samples.


11.6.1 Using the percent solids determined in Section 11.2.1 or 11.2.2, determine the volume of sample that will provide 10 g of solids, up to 1 L of sample.


11.6.2 Pressure filter the amount of sample determined in Section 11.6.1 through Whatman GF/D glass-fiber filter paper (Section 6.5.3). Pressure filter the blank and OPR aliquots through GF/D papers also. If necessary to separate the phases and/or settle the solids, centrifuge these aliquots prior to filtration.


11.6.3 Discard any aqueous phase (if present). Remove any non-aqueous liquid present and reserve the maximum amount filtered from the sample (Section 11.6.1) or 10 g, whichever is less, for combination with the solid phase (Section 12.3.5).


11.6.4 If particles >1mm are present in the sample (as determined in Section 11.3.2) and the sample is capable of being dried, spread the sample and QC aliquots on clean aluminum foil in a hood. After the aliquots are dry or if the sample cannot be dried, reduce the particle size using the procedures in Section 11.7 and extract the reduced particles using the SDS procedure in Section 12.3. If particles >1mm are not present, extract the particles and filter in the sample and QC aliquots directly using the SDS procedure in Section 12.3.


11.7 Sample grinding, homogenization, or blending—Samples with particle sizes greater than 1 mm (as determined in Section 11.3.2) are subjected to grinding, homogenization, or blending. The method of reducing particle size to less than 1 mm is matrix-dependent. In general, hard particles can be reduced by grinding with a mortar and pestle. Softer particles can be reduced by grinding in a Wiley mill or meat grinder, by homogenization, or in a blender.


11.7.1 Each size-reducing preparation procedure on each matrix shall be verified by running the tests in Section 9.2 before the procedure is employed routinely.


11.7.2 The grinding, homogenization, or blending procedures shall be carried out in a glove box or fume hood to prevent particles from contaminating the work environment.


11.7.3 Grinding—Certain papers and pulps, slurries, and amorphous solids can be ground in a Wiley mill or heavy duty meat grinder. In some cases, reducing the temperature of the sample to freezing or to dry ice or liquid nitrogen temperatures can aid in the grinding process. Grind the sample aliquots from Section 11.5.7 or 11.6.4 in a clean grinder. Do not allow the sample temperature to exceed 50 °C. Grind the blank and reference matrix aliquots using a clean grinder.


11.7.4 Homogenization or blending—Particles that are not ground effectively, or particles greater than 1 mm in size after grinding, can often be reduced in size by high speed homogenization or blending. Homogenize and/or blend the particles or filter from Section 11.5.7 or 11.6.4 for the sample, blank, and OPR aliquots.


11.7.5 Extract the aliquots using the SDS procedure in Section 12.3.


11.8 Fish and Other Tissues—Prior to processing tissue samples, the laboratory must determine the exact tissue to be analyzed. Common requests for analysis of fish tissue include whole fish—skin on, whole fish—skin removed, edible fish fillets (filleted in the field or by the laboratory), specific organs, and other portions. Once the appropriate tissue has been determined, the sample must be homogenized.


11.8.1 Homogenization.


11.8.1.1 Samples are homogenized while still frozen, where practical. If the laboratory must dissect the whole fish to obtain the appropriate tissue for analysis, the unused tissues may be rapidly refrozen and stored in a clean glass jar for subsequent use.


11.8.1.2 Each analysis requires 10 g of tissue (wet weight). Therefore, the laboratory should homogenize at least 20 g of tissue to allow for re-extraction of a second aliquot of the same homogenized sample, if re-analysis is required. When whole fish analysis is necessary, the entire fish is homogenized.


11.8.1.3 Homogenize the sample in a tissue homogenizer (Section 6.3.3) or grind in a meat grinder (Section 6.3.4). Cut tissue too large to feed into the grinder into smaller pieces. To assure homogeneity, grind three times.


11.8.1.4 Transfer approximately 10 g (wet weight) of homogenized tissue to a clean, tared, 400-500 mL beaker. For the alternate HCl digestion/extraction, transfer the tissue to a clean, tared 500-600 mL wide-mouth bottle. Record the weight to the nearest 10 mg.


11.8.1.5 Transfer the remaining homogenized tissue to a clean jar with a fluoropolymer-lined lid. Seal the jar and store the tissue at

11.8.2 QC aliquots.


11.8.2.1 Prepare a method blank by adding approximately 10 g of the oily liquid reference matrix (Section 7.6.4) to a 400-500 mL beaker. For the alternate HCl digestion/extraction, add the reference matrix to a 500-600 mL wide-mouth bottle. Record the weight to the nearest 10 mg.


11.8.2.2 Prepare a precision and recovery aliquot by adding approximately 10 g of the oily liquid reference matrix (Section 7.6.4) to a separate 400-500 mL beaker or wide-mouth bottle, depending on the extraction procedure to be used. Record the weight to the nearest 10 mg. If the initial precision and recovery test is to be performed, use four aliquots; if the ongoing precision and recovery test is to be performed, use a single aliquot.


11.8.3 Spiking


11.8.3.1 Spike 1.0 mL of the labeled compound spiking solution (Section 7.10.3) into the sample, blank, and OPR aliquot.


11.8.3.2 Spike 1.0 mL of the PAR standard (Section 7.14) into the OPR aliquot.


11.8.4 Extract the aliquots using the procedures in Section 12.4.


12.0 Extraction and Concentration

Extraction procedures include separatory funnel (Section 12.1) and solid phase (Section 12.2) for aqueous liquids; Soxhlet/Dean-Stark (Section 12.3) for solids, filters, and SPE disks; and Soxhlet extraction (Section 12.4.1) and HCl digestion (Section 12.4.2) for tissues. Acid/base back-extraction (Section 12.5) is used for initial cleanup of extracts.


Macro-concentration procedures include rotary evaporation (Section 12.6.1), heating mantle (Section 12.6.2), and Kuderna-Danish (K-D) evaporation (Section 12.6.3). Micro-concentration uses nitrogen blowdown (Section 12.7).


12.1 Separatory funnel extraction of filtrates and of aqueous samples visibly absent particles.


12.1.1 Pour the spiked sample (Section 11.4.2.2) or filtrate (Section 11.4.3.5) into a 2 L separatory funnel. Rinse the bottle or flask twice with 5 mL of reagent water and add these rinses to the separatory funnel.


12.1.2 Add 60 mL methylene chloride to the empty sample bottle (Section 12.1.1), seal, and shake 60 seconds to rinse the inner surface. Transfer the solvent to the separatory funnel, and extract the sample by shaking the funnel for two minutes with periodic venting. Allow the organic layer to separate from the aqueous phase for a minimum of 10 minutes. If an emulsion forms and is more than one-third the volume of the solvent layer, employ mechanical techniques to complete the phase separation (see note below). Drain the methylene chloride extract through a solvent-rinsed glass funnel approximately one-half full of granular anhydrous sodium sulfate (Section 7.2.1) supported on clean glass-fiber paper into a solvent-rinsed concentration device (Section 12.6).



Note:

If an emulsion forms, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration through glass wool, use of phase separation paper, centrifugation, use of an ultrasonic bath with ice, addition of NaCl, or other physical methods. Alternatively, solid-phase or other extraction techniques may be used to prevent emulsion formation. Any alternative technique is acceptable so long as the requirements in Section 9 are met.


Experience with aqueous samples high in dissolved organic materials (e.g., paper mill effluents) has shown that acidification of the sample prior to extraction may reduce the formation of emulsions. Paper industry methods suggest that the addition of up to 400 mL of ethanol to a 1 L effluent sample may also reduce emulsion formation. However, studies by EPA suggest that the effect may be a result of sample dilution, and that the addition of reagent water may serve the same function. Mechanical techniques may still be necessary to complete the phase separation. If either acidification or addition of ethanol is utilized, the laboratory must perform the startup tests described in Section 9.2 using the same techniques.


12.1.3 Extract the water sample two more times with 60 mL portions of methylene chloride. Drain each portion through the sodium sulfate into the concentrator. After the third extraction, rinse the separatory funnel with at least 20 mL of methylene chloride, and drain this rinse through the sodium sulfate into the concentrator. Repeat this rinse at least twice. Set aside the funnel with sodium sulfate if the extract is to be combined with the extract from the particles.


12.1.4 Concentrate the extract using one of the macro-concentration procedures in Section 12.6.


12.1.4.1 If the extract is from a sample visibly absent particles (Section 11.1.2.1), adjust the final volume of the concentrated extract to approximately 10 mL with hexane, transfer to a 250 mL separatory funnel, and back-extract using the procedure in Section 12.5.


12.1.4.2 If the extract is from the aqueous filtrate (Section 11.4.3.5), set aside the concentration apparatus for addition of the SDS extract from the particles (Section 12.3.9.1.2).


12.2 SPE of Samples Containing Less Than 1% Solids (References 19-20).


12.2.1 Disk preparation.


12.2.1.1 Place an SPE disk on the base of the filter holder (Figure 4) and wet with toluene. While holding a GMF 150 filter above the SPE disk with tweezers, wet the filter with toluene and lay the filter on the SPE disk, making sure that air is not trapped between the filter and disk. Clamp the filter and SPE disk between the 1 L glass reservoir and the vacuum filtration flask.


12.2.1.2 Rinse the sides of the filtration flask with approx 15 mL of toluene using a squeeze bottle or syringe. Apply vacuum momentarily until a few drops appear at the drip tip. Release the vacuum and allow the filter/disk to soak for approx one minute. Apply vacuum and draw all of the toluene through the filter/disk. Repeat the wash step with approx 15 mL of acetone and allow the filter/disk to air dry.


12.2.1.3 Re-wet the filter/disk with approximately 15 mL of methanol, allowing the filter/disk to soak for approximately one minute. Pull the methanol through the filter/disk using the vacuum, but retain a layer of methanol approximately 1 mm thick on the filter. Do not allow the disk to go dry from this point until the end of the extraction.


12.2.1.4 Rinse the filter/disk with two 50-mL portions of reagent water by adding the water to the reservoir and pulling most through, leaving a layer of water on the surface of the filter.


12.2.2 Extraction.


12.2.2.1 Pour the spiked sample (Section 11.4.2.2), blank (Section 11.4.2.4), or IPR/OPR aliquot (Section 11.4.2.5) into the reservoir and turn on the vacuum to begin the extraction. Adjust the vacuum to complete the extraction in no less than 10 minutes. For samples containing a high concentration of particles (suspended solids), filtration times may be eight hours or longer.


12.2.2.2 Before all of the sample has been pulled through the filter/disk, rinse the sample bottle with approximately 50 mL of reagent water to remove any solids, and pour into the reservoir. Pull through the filter/disk. Use additional reagent water rinses until all visible solids are removed.


12.2.2.3 Before all of the sample and rinses have been pulled through the filter/disk, rinse the sides of the reservoir with small portions of reagent water.


12.2.2.4 Allow the filter/disk to dry, then remove the filter and disk and place in a glass Petri dish. Extract the filter and disk per Section 12.3.


12.3 SDS Extraction of Samples Containing Particles, and of Filters and/or Disks.


12.3.1 Charge a clean extraction thimble (Section 6.4.2.2) with 5.0 g of 100/200 mesh silica (Section 7.5.1.1) topped with 100 g of quartz sand (Section 7.3.2).



Note:

Do not disturb the silica layer throughout the extraction process.


12.3.2 Place the thimble in a clean extractor. Place 30-40 mL of toluene in the receiver and 200-250 mL of toluene in the flask.


12.3.3 Pre-extract the glassware by heating the flask until the toluene is boiling. When properly adjusted, one to two drops of toluene will fall per second from the condenser tip into the receiver. Extract the apparatus for a minimum of three hours.


12.3.4 After pre-extraction, cool and disassemble the apparatus. Rinse the thimble with toluene and allow to air dry.


12.3.5 Load the wet sample, filter, and/or disk from Section 11.4.3.6, 11.5.8, 11.6.4, 11.7.3, 11.7.4, or 12.2.2.4 and any nonaqueous liquid from Section 11.6.3 into the thimble and manually mix into the sand layer with a clean metal spatula, carefully breaking up any large lumps of sample.


12.3.6 Reassemble the pre-extracted SDS apparatus, and add a fresh charge of toluene to the receiver and reflux flask. Apply power to the heating mantle to begin refluxing. Adjust the reflux rate to match the rate of percolation through the sand and silica beds until water removal lessens the restriction to toluene flow. Frequently check the apparatus for foaming during the first two hours of extraction. If foaming occurs, reduce the reflux rate until foaming subsides.


12.3.7 Drain the water from the receiver at one to two hours and eight to nine hours, or sooner if the receiver fills with water. Reflux the sample for a total of 16-24 hours. Cool and disassemble the apparatus. Record the total volume of water collected.


12.3.8 Remove the distilling flask. Drain the water from the Dean-Stark receiver and add any toluene in the receiver to the extract in the flask.


12.3.9 Concentrate the extract using one of the macro-concentration procedures in Section 12.6 per the following:


12.3.9.1 Extracts from the particles in an aqueous sample containing less than 1% solids (Section 11.4.3.6).


12.3.9.1.1 Concentrate the extract to approximately 5 mL using the rotary evaporator or heating mantle procedures in Section 12.6.1 or 12.6.2.


12.3.9.1.2 Quantitatively transfer the extract through the sodium sulfate (Section 12.1.3) into the apparatus that was set aside (Section 12.1.4.2) and reconcentrate to the level of the toluene.


12.3.9.1.3 Adjust to approximately 10 mL with hexane, transfer to a 250 mL separatory funnel, and proceed with back-extraction (Section 12.5).


12.3.9.2 Extracts from particles (Sections 11.5 through 11.6) or from the SPE filter and disk (Section 12.2.2.4)—Concentrate to approximately 10 mL using the rotary evaporator or heating mantle (Section 12.6.1 or 12.6.2), transfer to a 250 mL separatory funnel, and proceed with back-extraction (Section 12.5).


12.4 Extraction of Tissue—Two procedures are provided for tissue extraction.


12.4.1 Soxhlet extraction (Reference 21).


12.4.1.1 Add 30-40 g of powdered anhydrous sodium sulfate to each of the beakers (Section 11.8.4) and mix thoroughly. Cover the beakers with aluminum foil and allow to equilibrate for 12-24 hours. Remix prior to extraction to prevent clumping.


12.4.1.2 Assemble and pre-extract the Soxhlet apparatus per Sections 12.3.1 through 12.3.4, except use the methylene chloride:hexane (1:1) mixture for the pre-extraction and rinsing and omit the quartz sand. The Dean-Stark moisture trap may also be omitted, if desired.


12.4.1.3 Reassemble the pre-extracted Soxhlet apparatus and add a fresh charge of methylene chloride:hexane to the reflux flask.


12.4.1.4 Transfer the sample/sodium sulfate mixture (Section 12.4.1.1) to the Soxhlet thimble, and install the thimble in the Soxhlet apparatus.


12.4.1.5 Rinse the beaker with several portions of solvent mixture and add to the thimble. Fill the thimble/receiver with solvent. Extract for 18-24 hours.


12.4.1.6 After extraction, cool and disassemble the apparatus.


12.4.1.7 Quantitatively transfer the extract to a macro-concentration device (Section 12.6), and concentrate to near dryness. Set aside the concentration apparatus for re-use.


12.4.1.8 Complete the removal of the solvent using the nitrogen blowdown procedure (Section 12.7) and a water bath temperature of 60 °C. Weigh the receiver, record the weight, and return the receiver to the blowdown apparatus, concentrating the residue until a constant weight is obtained.


12.4.1.9 Percent lipid determination—The lipid content is determined by extraction of tissue with the same solvent system (methylene chloride:hexane) that was used in EPA’s National Dioxin Study (Reference 22) so that lipid contents are consistent with that study.


12.4.1.9.1 Redissolve the residue in the receiver in hexane and spike 1.0 mL of the cleanup standard (Section 7.11) into the solution.


12.4.1.9.2 Transfer the residue/hexane to the anthropogenic isolation column (Section 13.7.1) or bottle for the acidified silica gel batch cleanup (Section 13.7.2), retaining the boiling chips in the concentration apparatus. Use several rinses to assure that all material is transferred. If necessary, sonicate or heat the receiver slightly to assure that all material is re-dissolved. Allow the receiver to dry. Weigh the receiver and boiling chips.


12.4.1.9.3 Calculate the lipid content to the nearest three significant figures as follows:



12.4.1.9.4 It is not necessary to determine the lipid content of the blank, IPR, or OPR aliquots.


12.4.2 HCl digestion/extraction and concentration (References 23-26).


12.4.2.1 Add 200 mL of 6 N HCl and 200 mL of methylene chloride:hexane (1:1) to the sample and QC aliquots (Section 11.8.4).


12.4.2.2 Cap and shake each bottle one to three times. Loosen the cap in a hood to vent excess pressure. Shake each bottle for 10-30 seconds and vent.


12.4.2.3 Tightly cap and place on shaker. Adjust the shaker action and speed so that the acid, solvent, and tissue are in constant motion. However, take care to avoid such violent action that the bottle may be dislodged from the shaker. Shake for 12-24 hours.


12.4.2.4 After digestion, remove the bottles from the shaker. Allow the bottles to stand so that the solvent and acid layers separate.


12.4.2.5 Decant the solvent through a glass funnel with glass-fiber filter (Sections 6.5.2 through 6.5.3) containing approximately 10 g of granular anhydrous sodium sulfate (Section 7.2.1) into a macro-concentration apparatus (Section 12.6). Rinse the contents of the bottle with two 25 mL portions of hexane and pour through the sodium sulfate into the apparatus.


12.4.2.6 Concentrate the solvent to near dryness using a macro-concentration procedure (Section 12.6).


12.4.2.7 Complete the removal of the solvent using the nitrogen blowdown apparatus (Section 12.7) and a water bath temperature of 60 °C. Weigh the receiver, record the weight, and return the receiver to the blowdown apparatus, concentrating the residue until a constant weight is obtained.


12.4.2.8 Percent lipid determination—The lipid content is determined in the same solvent system [methylene chloride:hexane (1:1)] that was used in EPA’s National Dioxin Study (Reference 22) so that lipid contents are consistent with that study.


12.4.2.8.1 Redissolve the residue in the receiver in hexane and spike 1.0 mL of the cleanup standard (Section 7.11) into the solution.


12.4.2.8.2 Transfer the residue/hexane to the narrow-mouth 100-200 mL bottle retaining the boiling chips in the receiver. Use several rinses to assure that all material is transferred, to a maximum hexane volume of approximately 70 mL. Allow the receiver to dry. Weigh the receiver and boiling chips.


12.4.2.8.3 Calculate the percent lipid per Section 12.4.1.9.3. It is not necessary to determine the lipid content of the blank, IPR, or OPR aliquots.


12.4.2.9 Clean up the extract per Section 13.7.3.


12.5 Back-Extraction with Base and Acid.


12.5.1 Spike 1.0 mL of the cleanup standard (Section 7.11) into the separatory funnels containing the sample and QC extracts from Section 12.1.4.1, 12.3.9.1.3, or 12.3.9.2.


12.5.2 Partition the extract against 50 mL of potassium hydroxide solution (Section 7.1.1). Shake for two minutes with periodic venting into a hood. Remove and discard the aqueous layer. Repeat the base washing until no color is visible in the aqueous layer, to a maximum of four washings. Minimize contact time between the extract and the base to prevent degradation of the CDDs/CDFs. Stronger potassium hydroxide solutions may be employed for back-extraction, provided that the laboratory meets the specifications for labeled compound recovery and demonstrates acceptable performance using the procedure in Section 9.2.


12.5.3 Partition the extract against 50 mL of sodium chloride solution (Section 7.1.4) in the same way as with base. Discard the aqueous layer.


12.5.4 Partition the extract against 50 mL of sulfuric acid (Section 7.1.2) in the same way as with base. Repeat the acid washing until no color is visible in the aqueous layer, to a maximum of four washings.


12.5.5 Repeat the partitioning against sodium chloride solution and discard the aqueous layer.


12.5.6 Pour each extract through a drying column containing 7-10 cm of granular anhydrous sodium sulfate (Section 7.2.1). Rinse the separatory funnel with 30-50 mL of solvent, and pour through the drying column. Collect each extract in a round-bottom flask. Re-concentrate the sample and QC aliquots per Sections 12.6 through 12.7, and clean up the samples and QC aliquots per Section 13.


12.6 Macro-Concentration—Extracts in toluene are concentrated using a rotary evaporator or a heating mantle; extracts in methylene chloride or hexane are concentrated using a rotary evaporator, heating mantle, or Kuderna-Danish apparatus.


12.6.1 Rotary evaporation—Concentrate the extracts in separate round-bottom flasks.


12.6.1.1 Assemble the rotary evaporator according to manufacturer’s instructions, and warm the water bath to 45 °C. On a daily basis, preclean the rotary evaporator by concentrating 100 mL of clean extraction solvent through the system. Archive both the concentrated solvent and the solvent in the catch flask for a contamination check if necessary. Between samples, three 2-3 mL aliquots of solvent should be rinsed down the feed tube into a waste beaker.


12.6.1.2 Attach the round-bottom flask containing the sample extract to the rotary evaporator. Slowly apply vacuum to the system, and begin rotating the sample flask.


12.6.1.3 Lower the flask into the water bath, and adjust the speed of rotation and the temperature as required to complete concentration in 15-20 minutes. At the proper rate of concentration, the flow of solvent into the receiving flask will be steady, but no bumping or visible boiling of the extract will occur.



Note:

If the rate of concentration is too fast, analyte loss may occur.


12.6.1.4 When the liquid in the concentration flask has reached an apparent volume of approximately 2 mL, remove the flask from the water bath and stop the rotation. Slowly and carefully admit air into the system. Be sure not to open the valve so quickly that the sample is blown out of the flask. Rinse the feed tube with approximately 2 mL of solvent.


12.6.1.5 Proceed to Section 12.6.4 for preparation for back-extraction or micro-concentration and solvent exchange.


12.6.2 Heating mantle—Concentrate the extracts in separate round-bottom flasks.


12.6.2.1 Add one or two clean boiling chips to the round-bottom flask, and attach a three-ball macro Snyder column. Prewet the column by adding approximately 1 mL of solvent through the top. Place the round-bottom flask in a heating mantle, and apply heat as required to complete the concentration in 15-20 minutes. At the proper rate of distillation, the balls of the column will actively chatter, but the chambers will not flood.


12.6.2.2 When the liquid has reached an apparent volume of approximately 10 mL, remove the round-bottom flask from the heating mantle and allow the solvent to drain and cool for at least 10 minutes. Remove the Snyder column and rinse the glass joint into the receiver with small portions of solvent.


12.6.2.3 Proceed to Section 12.6.4 for preparation for back-extraction or micro-concentration and solvent exchange.


12.6.3 Kuderna-Danish (K-D)—Concentrate the extracts in separate 500 mL K-D flasks equipped with 10 mL concentrator tubes. The K-D technique is used for solvents such as methylene chloride and hexane. Toluene is difficult to concentrate using the K-D technique unless a water bath fed by a steam generator is used.


12.6.3.1 Add one to two clean boiling chips to the receiver. Attach a three-ball macro Snyder column. Prewet the column by adding approximately 1 mL of solvent through the top. Place the K-D apparatus in a hot water bath so that the entire lower rounded surface of the flask is bathed with steam.


12.6.3.2 Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15-20 minutes. At the proper rate of distillation, the balls of the column will actively chatter but the chambers will not flood.


12.6.3.3 When the liquid has reached an apparent volume of 1 mL, remove the K-D apparatus from the bath and allow the solvent to drain and cool for at least 10 minutes. Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1-2 mL of solvent. A 5 mL syringe is recommended for this operation.


12.6.3.4 Remove the three-ball Snyder column, add a fresh boiling chip, and attach a two-ball micro Snyder column to the concentrator tube. Prewet the column by adding approximately 0.5 mL of solvent through the top. Place the apparatus in the hot water bath.


12.6.3.5 Adjust the vertical position and the water temperature as required to complete the concentration in 5-10 minutes. At the proper rate of distillation, the balls of the column will actively chatter but the chambers will not flood.


12.6.3.6 When the liquid reaches an apparent volume of 0.5 mL, remove the apparatus from the water bath and allow to drain and cool for at least 10 minutes.


12.6.3.7 Proceed to 12.6.4 for preparation for back-extraction or micro-concentration and solvent exchange.


12.6.4 Preparation for back-extraction or micro-concentration and solvent exchange.


12.6.4.1 For back-extraction (Section 12.5), transfer the extract to a 250 mL separatory funnel. Rinse the concentration vessel with small portions of hexane, adjust the hexane volume in the separatory funnel to 10-20 mL, and proceed to back-extraction (Section 12.5).


12.6.4.2 For determination of the weight of residue in the extract, or for clean-up procedures other than back-extraction, transfer the extract to a blowdown vial using two to three rinses of solvent. Proceed with micro-concentration and solvent exchange (Section 12.7).


12.7 Micro-Concentration and Solvent Exchange.


12.7.1 Extracts to be subjected to GPC or HPLC cleanup are exchanged into methylene chloride. Extracts to be cleaned up using silica gel, alumina, carbon, and/or Florisil are exchanged into hexane.


12.7.2 Transfer the vial containing the sample extract to a nitrogen blowdown device. Adjust the flow of nitrogen so that the surface of the solvent is just visibly disturbed.



Note:

A large vortex in the solvent may cause analyte loss.


12.7.3 Lower the vial into a 45 °C water bath and continue concentrating.


12.7.3.1 If the extract is to be concentrated to dryness for weight determination (Sections 12.4.1.8, 12.4.2.7, and 13.7.1.4), blow dry until a constant weight is obtained.


12.7.3.2 If the extract is to be concentrated for injection into the GC/MS or the solvent is to be exchanged for extract cleanup, proceed as follows:


12.7.4 When the volume of the liquid is approximately 100 L, add 2-3 mL of the desired solvent (methylene chloride for GPC and HPLC, or hexane for the other cleanups) and continue concentration to approximately 100 µL. Repeat the addition of solvent and concentrate once more.


12.7.5 If the extract is to be cleaned up by GPC, adjust the volume of the extract to 5.0 mL with methylene chloride. If the extract is to be cleaned up by HPLC, further concentrate the extract to 30 µL. Proceed with GPC or HPLC cleanup (Section 13.2 or 13.6, respectively).


12.7.6 If the extract is to be cleaned up by column chromatography (alumina, silica gel, Carbopak/Celite, or Florisil), bring the final volume to 1.0 mL with hexane. Proceed with column cleanups (Sections 13.3 through 13.5 and 13.8).


12.7.7 If the extract is to be concentrated for injection into the GC/MS (Section 14), quantitatively transfer the extract to a 0.3 mL conical vial for final concentration, rinsing the larger vial with hexane and adding the rinse to the conical vial. Reduce the volume to approximately 100 µL. Add 10 µL of nonane to the vial, and evaporate the solvent to the level of the nonane. Seal the vial and label with the sample number. Store in the dark at room temperature until ready for GC/MS analysis. If GC/MS analysis will not be performed on the same day, store the vial at
13.0 Extract Cleanup

13.1 Cleanup may not be necessary for relatively clean samples (e.g., treated effluents, groundwater, drinking water). If particular circumstances require the use of a cleanup procedure, the analyst may use any or all of the procedures below or any other appropriate procedure. Before using a cleanup procedure, the analyst must demonstrate that the requirements of Section 9.2 can be met using the cleanup procedure. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, the cleanup procedures may be optimized for isolation of these two compounds.


13.1.1 Gel permeation chromatography (Section 13.2) removes high molecular weight interferences that cause GC column performance to degrade. It should be used for all soil and sediment extracts and may be used for water extracts that are expected to contain high molecular weight organic compounds (e.g., polymeric materials, humic acids).


13.1.2 Acid, neutral, and basic silica gel (Section 13.3), alumina (Section 13.4), and Florisil (Section 13.8) are used to remove nonpolar and polar interferences. Alumina and Florisil are used to remove chlorodiphenyl ethers.


13.1.3 Carbopak/Celite (Section 13.5) is used to remove nonpolar interferences.


13.1.4 HPLC (Section 13.6) is used to provide specificity for the 2,3,7,8-substituted and other CDD and CDF isomers.


13.1.5 The anthropogenic isolation column (Section 13.7.1), acidified silica gel batch adsorption procedure (Section 13.7.2), and sulfuric acid and base back-extraction (Section 13.7.3) are used for removal of lipids from tissue samples.


13.2 Gel Permeation Chromatography (GPC).


13.2.1 Column packing.


13.2.1.1 Place 70-75 g of SX-3 Bio-beads (Section 6.7.1.1) in a 400-500 mL beaker.


13.2.1.2 Cover the beads with methylene chloride and allow to swell overnight (a minimum of 12 hours).


13.2.1.3 Transfer the swelled beads to the column (Section 6.7.1.1) and pump solvent through the column, from bottom to top, at 4.5-5.5 mL/minute prior to connecting the column to the detector.


13.2.1.4 After purging the column with solvent for one to two hours, adjust the column head pressure to 7-10 psig and purge for four to five hours to remove air. Maintain a head pressure of 7-10 psig. Connect the column to the detector (Section 6.7.1.4).


13.2.2 Column calibration.


13.2.2.1 Load 5 mL of the calibration solution (Section 7.4) into the sample loop.


13.2.2.2 Inject the calibration solution and record the signal from the detector. The elution pattern will be corn oil, bis(2-ethyl hexyl)phthalate, pentachlorophenol, perylene, and sulfur.


13.2.2.3 Set the “dump time” to allow >85% removal of the corn oil and >85% collection of the phthalate.


13.2.2.4 Set the “collect time” to the peak minimum between perylene and sulfur.


13.2.2.5 Verify the calibration with the calibration solution after every 20 extracts. Calibration is verified if the recovery of the pentachlorophenol is greater than 85%. If calibration is not verified, the system shall be recalibrated using the calibration solution, and the previous 20 samples shall be re-extracted and cleaned up using the calibrated GPC system.


13.2.3 Extract cleanup—GPC requires that the column not be overloaded. The column specified in this method is designed to handle a maximum of 0.5 g of high molecular weight material in a 5 mL extract. If the extract is known or expected to contain more than 0.5 g, the extract is split into aliquots for GPC, and the aliquots are combined after elution from the column. The residue content of the extract may be obtained gravimetrically by evaporating the solvent from a 50 µL aliquot.


13.2.3.1 Filter the extract or load through the filter holder (Section 6.7.1.3) to remove the particles. Load the 5.0 mL extract onto the column.


13.2.3.2 Elute the extract using the calibration data determined in Section 13.2.2. Collect the eluate in a clean 400-500 mL beaker.


13.2.3.3 Rinse the sample loading tube thoroughly with methylene chloride between extracts to prepare for the next sample.


13.2.3.4 If a particularly dirty extract is encountered, a 5.0 mL methylene chloride blank shall be run through the system to check for carry-over.


13.2.3.5 Concentrate the eluate per Sections 12.6 and 12.7 for further cleanup or injection into the GC/MS.


13.3 Silica Gel Cleanup.


13.3.1 Place a glass-wool plug in a 15 mm ID chromatography column (Section 6.7.4.2). Pack the column bottom to top with: 1 g silica gel (Section 7.5.1.1), 4 g basic silica gel (Section 7.5.1.3), 1 g silica gel, 8 g acid silica gel (Section 7.5.1.2), 2 g silica gel, and 4 g granular anhydrous sodium sulfate (Section 7.2.1). Tap the column to settle the adsorbents.


13.3.2 Pre-elute the column with 50-100 mL of hexane. Close the stopcock when the hexane is within 1 mm of the sodium sulfate. Discard the eluate. Check the column for channeling. If channeling is present, discard the column and prepare another.


13.3.3 Apply the concentrated extract to the column. Open the stopcock until the extract is within 1 mm of the sodium sulfate.


13.3.4 Rinse the receiver twice with 1 mL portions of hexane, and apply separately to the column. Elute the CDDs/CDFs with 100 mL hexane, and collect the eluate.


13.3.5 Concentrate the eluate per Sections 12.6 and 12.7 for further cleanup or injection into the HPLC or GC/MS.


13.3.6 For extracts of samples known to contain large quantities of other organic compounds (such as paper mill effluents), it may be advisable to increase the capacity of the silica gel column. This may be accomplished by increasing the strengths of the acid and basic silica gels. The acid silica gel (Section 7.5.1.2) may be increased in strength to as much as 44% w/w (7.9 g sulfuric acid added to 10 g silica gel). The basic silica gel (Section 7.5.1.3) may be increased in strength to as much as 33% w/w (50 mL 1N NaOH added to 100 g silica gel), or the potassium silicate (Section 7.5.1.4) may be used.



Note:

The use of stronger acid silica gel (44% w/w) may lead to charring of organic compounds in some extracts. The charred material may retain some of the analytes and lead to lower recoveries of CDDs/CDFs. Increasing the strengths of the acid and basic silica gel may also require different volumes of hexane than those specified above to elute the analytes off the column. Therefore, the performance of the method after such modifications must be verified by the procedure in Section 9.2.


13.4 Alumina Cleanup.


13.4.1 Place a glass-wool plug in a 15 mm ID chromatography column (Section 6.7.4.2).


13.4.2 If using acid alumina, pack the column by adding 6 g acid alumina (Section 7.5.2.1). If using basic alumina, substitute 6 g basic alumina (Section 7.5.2.2). Tap the column to settle the adsorbents.


13.4.3 Pre-elute the column with 50-100 mL of hexane. Close the stopcock when the hexane is within 1 mm of the alumina.


13.4.4 Discard the eluate. Check the column for channeling. If channeling is present, discard the column and prepare another.


13.4.5 Apply the concentrated extract to the column. Open the stopcock until the extract is within 1 mm of the alumina.


13.4.6 Rinse the receiver twice with 1 mL portions of hexane and apply separately to the column. Elute the interfering compounds with 100 mL hexane and discard the eluate.


13.4.7 The choice of eluting solvents will depend on the choice of alumina (acid or basic) made in Section 13.4.2.


13.4.7.1 If using acid alumina, elute the CDDs/CDFs from the column with 20 mL methylene chloride:hexane (20:80 v/v). Collect the eluate.


13.4.7.2 If using basic alumina, elute the CDDs/CDFs from the column with 20 mL methylene chloride:hexane (50:50 v/v). Collect the eluate.


13.4.8 Concentrate the eluate per Sections 12.6 and 12.7 for further cleanup or injection into the HPLC or GC/MS.


13.5 Carbon Column.


13.5.1 Cut both ends from a 10 mL disposable serological pipet (Section 6.7.3.2) to produce a 10 cm column. Fire-polish both ends and flare both ends if desired. Insert a glass-wool plug at one end, and pack the column with 0.55 g of Carbopak/Celite (Section 7.5.3.3) to form an adsorbent bed approximately 2 cm long. Insert a glass-wool plug on top of the bed to hold the adsorbent in place.


13.5.2 Pre-elute the column with 5 mL of toluene followed by 2 mL of methylene chloride: methanol:toluene (15:4:1 v/v), 1 mL of methylene chloride:cyclohexane (1:1 v/v), and 5 mL of hexane. If the flow rate of eluate exceeds 0.5 mL/minute, discard the column.


13.5.3 When the solvent is within 1 mm of the column packing, apply the sample extract to the column. Rinse the sample container twice with 1 mL portions of hexane and apply separately to the column. Apply 2 mL of hexane to complete the transfer.


13.5.4 Elute the interfering compounds with two 3 mL portions of hexane, 2 mL of methylene chloride:cyclohexane (1:1 v/v), and 2 mL of methylene chloride:methanol:toluene (15:4:1 v/v). Discard the eluate.


13.5.5 Invert the column, and elute the CDDs/CDFs with 20 mL of toluene. If carbon particles are present in the eluate, filter through glass-fiber filter paper.


13.5.6 Concentrate the eluate per Sections 12.6 and 12.7 for further cleanup or injection into the HPLC or GC/MS.


13.6 HPLC (Reference 6).


13.6.1 Column calibration.


13.6.1.1 Prepare a calibration standard containing the 2,3,7,8-substituted isomers and/or other isomers of interest at a concentration of approximately 500 pg/µL in methylene chloride.


13.6.1.2 Inject 30 µL of the calibration solution into the HPLC and record the signal from the detector. Collect the eluant for reuse. The elution order will be the tetra- through octa-isomers.


13.6.1.3 Establish the collection time for the tetra-isomers and for the other isomers of interest. Following calibration, flush the injection system with copious quantities of methylene chloride, including a minimum of five 50 µL injections while the detector is monitored, to ensure that residual CDDs/CDFs are removed from the system.


13.6.1.4 Verify the calibration with the calibration solution after every 20 extracts. Calibration is verified if the recovery of the CDDs/CDFs from the calibration standard (Section 13.6.1.1) is 75-125% compared to the calibration (Section 13.6.1.2). If calibration is not verified, the system shall be recalibrated using the calibration solution, and the previous 20 samples shall be re-extracted and cleaned up using the calibrated system.


13.6.2 Extract cleanup—HPLC requires that the column not be overloaded. The column specified in this method is designed to handle a maximum of 30 µL of extract. If the extract cannot be concentrated to less than 30 µL, it is split into fractions and the fractions are combined after elution from the column.


13.6.2.1 Rinse the sides of the vial twice with 30 µL of methylene chloride and reduce to 30 µL with the evaporation apparatus (Section 12.7).


13.6.2.2 Inject the 30 µL extract into the HPLC.


13.6.2.3 Elute the extract using the calibration data determined in Section 13.6.1. Collect the fraction(s) in a clean 20 mL concentrator tube containing 5 mL of hexane:acetone (1:1 v/v).


13.6.2.4 If an extract containing greater than 100 ng/mL of total CDD or CDF is encountered, a 30 µL methylene chloride blank shall be run through the system to check for carry-over.


13.6.2.5 Concentrate the eluate per Section 12.7 for injection into the GC/MS.


13.7 Cleanup of Tissue Lipids—Lipids are removed from the Soxhlet extract using either the anthropogenic isolation column (Section 13.7.1) or acidified silica gel (Section 13.7.2), or are removed from the HCl digested extract using sulfuric acid and base back-extraction (Section 13.7.3).


13.7.1 Anthropogenic isolation column (References 22 and 27)—Used for removal of lipids from the Soxhlet/SDS extraction (Section 12.4.1).


13.7.1.1 Prepare the column as given in Section 7.5.4.


13.7.1.2 Pre-elute the column with 100 mL of hexane. Drain the hexane layer to the top of the column, but do not expose the sodium sulfate.


13.7.1.3 Load the sample and rinses (Section 12.4.1.9.2) onto the column by draining each portion to the top of the bed. Elute the CDDs/CDFs from the column into the apparatus used for concentration (Section 12.4.1.7) using 200 mL of hexane.


13.7.1.4 Concentrate the cleaned up extract (Sections 12.6 through 12.7) to constant weight per Section 12.7.3.1. If more than 500 mg of material remains, repeat the cleanup using a fresh anthropogenic isolation column.


13.7.1.5 Redissolve the extract in a solvent suitable for the additional cleanups to be used (Sections 13.2 through 13.6 and 13.8).


13.7.1.6 Spike 1.0 mL of the cleanup standard (Section 7.11) into the residue/solvent.


13.7.1.7 Clean up the extract using the procedures in Sections 13.2 through 13.6 and 13.8. Alumina (Section 13.4) or Florisil (Section 13.8) and carbon (Section 13.5) are recommended as minimum additional cleanup steps.


13.7.1.8 Following cleanup, concentrate the extract to 10 µL as described in Section 12.7 and proceed with the analysis in Section 14.


13.7.2 Acidified silica gel (Reference 28)—Procedure alternate to the anthropogenic isolation column (Section 13.7.1) that is used for removal of lipids from the Soxhlet/SDS extraction (Section 12.4.1).


13.7.2.1 Adjust the volume of hexane in the bottle (Section 12.4.1.9.2) to approximately 200 mL.


13.7.2.2 Spike 1.0 mL of the cleanup standard (Section 7.11) into the residue/solvent.


13.7.2.3 Drop the stirring bar into the bottle, place the bottle on the stirring plate, and begin stirring.


13.7.2.4 Add 30-100 g of acid silica gel (Section 7.5.1.2) to the bottle while stirring, keeping the silica gel in motion. Stir for two to three hours.



Note:

30 grams of silica gel should be adequate for most samples and will minimize contamination from this source.


13.7.2.5 After stirring, pour the extract through approximately 10 g of granular anhydrous sodium sulfate (Section 7.2.1) contained in a funnel with glass-fiber filter into a macro contration device (Section 12.6). Rinse the bottle and sodium sulfate with hexane to complete the transfer.


13.7.2.6 Concentrate the extract per Sections 12.6 through 12.7 and clean up the extract using the procedures in Sections 13.2 through 13.6 and 13.8. Alumina (Section 13.4) or Florisil (Section 13.8) and carbon (Section 13.5) are recommended as minimum additional cleanup steps.


13.7.3 Sulfuric acid and base back-extraction. Used with HCl digested extracts (Section 12.4.2).


13.7.3.1 Spike 1.0 mL of the cleanup standard (Section 7.11) into the residue/solvent (Section 12.4.2.8.2).


13.7.3.2 Add 10 mL of concentrated sulfuric acid to the bottle. Immediately cap and shake one to three times. Loosen cap in a hood to vent excess pressure. Cap and shake the bottle so that the residue/solvent is exposed to the acid for a total time of approximately 45 seconds.


13.7.3.3 Decant the hexane into a 250 mL separatory funnel making sure that no acid is transferred. Complete the quantitative transfer with several hexane rinses.


13.7.3.4 Back extract the solvent/residue with 50 mL of potassium hydroxide solution per Section 12.5.2, followed by two reagent water rinses.


13.7.3.5 Drain the extract through a filter funnel containing approximately 10 g of granular anhydrous sodium sulfate in a glass-fiber filter into a macro concentration device (Section 12.6).


13.7.3.6 Concentrate the cleaned up extract to a volume suitable for the additional cleanups given in Sections 13.2 through 13.6 and 13.8. Gel permeation chromatography (Section 13.2), alumina (Section 13.4) or Florisil (Section 13.8), and Carbopak/Celite (Section 13.5) are recommended as minimum additional cleanup steps.


13.7.3.7 Following cleanup, concentrate the extract to 10 L as described in Section 12.7 and proceed with analysis per Section 14.


13.8 Florisil Cleanup (Reference 29).


13.8.1 Pre-elute the activated Florisil column (Section 7.5.3) with 10 mL of methylene chloride followed by 10 mL of hexane:methylene chloride (98:2 v/v) and discard the solvents.


13.8.2 When the solvent is within 1 mm of the packing, apply the sample extract (in hexane) to the column. Rinse the sample container twice with 1 mL portions of hexane and apply to the column.


13.8.3 Elute the interfering compounds with 20 mL of hexane:methylene chloride (98:2) and discard the eluate.


13.8.4 Elute the CDDs/CDFs with 35 mL of methylene chloride and collect the eluate. Concentrate the eluate per Sections 12.6 through 12.7 for further cleanup or for injection into the HPLC or GC/MS.


14.0 HRGC/HRMS Analysis

14.1 Establish the operating conditions given in Section 10.1.


14.2 Add 10 uL of the appropriate internal standard solution (Section 7.12) to the sample extract immediately prior to injection to minimize the possibility of loss by evaporation, adsorption, or reaction. If an extract is to be reanalyzed and evaporation has occurred, do not add more instrument internal standard solution. Rather, bring the extract back to its previous volume (e.g., 19 L) with pure nonane only (18 L if 2 L injections are used).


14.3 Inject 1.0 µL or 2.0 µL of the concentrated extract containing the internal standard solution, using on-column or splitless injection. The volume injected must be identical to the volume used for calibration (Section 10). Start the GC column initial isothermal hold upon injection. Start MS data collection after the solvent peak elutes. Stop data collection after the OCDD and OCDF have eluted. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, stop data collection after elution of these compounds. Return the column to the initial temperature for analysis of the next extract or standard.


15.0 System and Laboratory Performance

15.1 At the beginning of each 12-hour shift during which analyses are performed, GC/MS system performance and calibration are verified for all CDDs/CDFs and labeled compounds. For these tests, analysis of the CS3 calibration verification (VER) standard (Section 7.13 and Table 4) and the isomer specificity test standards (Section 7.15 and Table 5) shall be used to verify all performance criteria. Adjustment and/or recalibration (Section 10) shall be performed until all performance criteria are met. Only after all performance criteria are met may samples, blanks, IPRs, and OPRs be analyzed.


15.2 MS Resolution—A static resolving power of at least 10,000 (10% valley definition) must be demonstrated at the appropriate m/z before any analysis is performed. Static resolving power checks must be performed at the beginning and at the end of each 12-hour shift according to procedures in Section 10.1.2. Corrective actions must be implemented whenever the resolving power does not meet the requirement.


15.3 Calibration Verification.


15.3.1 Inject the VER standard using the procedure in Section 14.


15.3.2 The m/z abundance ratios for all CDDs/CDFs shall be within the limits in Table 9; otherwise, the mass spectrometer shall be adjusted until the m/z abundance ratios fall within the limits specified, and the verification test shall be repeated. If the adjustment alters the resolution of the mass spectrometer, resolution shall be verified (Section 10.1.2) prior to repeat of the verification test.


15.3.3 The peaks representing each CDD/CDF and labeled compound in the VER standard must be present with S/N of at least 10; otherwise, the mass spectrometer shall be adjusted and the verification test repeated.


15.3.4 Compute the concentration of each CDD/CDF compound by isotope dilution (Section 10.5) for those compounds that have labeled analogs (Table 1). Compute the concentration of the labeled compounds by the internal standard method (Section 10.6). These concentrations are computed based on the calibration data in Section 10.


15.3.5 For each compound, compare the concentration with the calibration verification limit in Table 6. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, compare the concentration to the limit in Table 6a. If all compounds meet the acceptance criteria, calibration has been verified and analysis of standards and sample extracts may proceed. If, however, any compound fails its respective limit, the measurement system is not performing properly for that compound. In this event, prepare a fresh calibration standard or correct the problem causing the failure and repeat the resolution (Section 15.2) and verification (Section 15.3) tests, or recalibrate (Section 10).


15.4 Retention Times and GC Resolution.


15.4.1 Retention times.


15.4.1.1 Absolute—The absolute retention times of the
13C12-1,2,3,4-TCDD and
13C12-1,2,3,7,8,9-HxCDD GCMS internal standards in the verification test (Section 15.3) shall be within ±15 seconds of the retention times obtained during calibration (Sections 10.2.1 and 10.2.4).


15.4.1.2 Relative—The relative retention times of CDDs/CDFs and labeled compounds in the verification test (Section 15.3) shall be within the limits given in Table 2.


15.4.2 GC resolution.


15.4.2.1 Inject the isomer specificity standards (Section 7.15) on their respective columns.


15.4.2.2 The valley height between 2,3,7,8-TCDD and the other tetra-dioxin isomers at m/z 319.8965, and between 2,3,7,8-TCDF and the other tetra-furan isomers at m/z 303.9016 shall not exceed 25% on their respective columns (Figures 6 and 7).


15.4.3 If the absolute retention time of any compound is not within the limits specified or if the 2,3,7,8-isomers are not resolved, the GC is not performing properly. In this event, adjust the GC and repeat the verification test (Section 15.3) or recalibrate (Section 10), or replace the GC column and either verify calibration or recalibrate.


15.5 Ongoing Precision and Recovery.


15.5.1 Analyze the extract of the ongoing precision and recovery (OPR) aliquot (Section 11.4.2.5, 11.5.4, 11.6.2, 11.7.4, or 11.8.3.2) prior to analysis of samples from the same batch.


15.5.2 Compute the concentration of each CDD/CDF by isotope dilution for those compounds that have labeled analogs (Section 10.5). Compute the concentration of 1,2,3,7,8,9-HxCDD, OCDF, and each labeled compound by the internal standard method (Section 10.6).


15.5.3 For each CDD/CDF and labeled compound, compare the concentration to the OPR limits given in Table 6. If only 2,3,7,8-TCDD and 2,3,7,8-TCDF are to be determined, compare the concentration to the limits in Table 6a. If all compounds meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may proceed. If, however, any individual concentration falls outside of the range given, the extraction/concentration processes are not being performed properly for that compound. In this event, correct the problem, re-prepare, extract, and clean up the sample batch and repeat the ongoing precision and recovery test (Section 15.5).


15.5.4 Add results that pass the specifications in Section 15.5.3 to initial and previous ongoing data for each compound in each matrix. Update QC charts to form a graphic representation of continued laboratory performance. Develop a statement of laboratory accuracy for each CDD/CDF in each matrix type by calculating the average percent recovery (R) and the standard deviation of percent recovery (SR). Express the accuracy as a recovery interval from R−2SR to R = 2SR. For example, if R = 95% and SR = 5%, the accuracy is 85-105%.


15.6 Blank—Analyze the method blank extracted with each sample batch immediately following analysis of the OPR aliquot to demonstrate freedom from contamination and freedom from carryover from the OPR analysis. The results of the analysis of the blank must meet the specifications in Section 9.5.2 before sample analyses may proceed.


16.0 Qualitative Determination

A CDD, CDF, or labeled compound is identified in a standard, blank, or sample when all of the criteria in Sections 16.1 through 16.4 are met.


16.1 The signals for the two exact m/z’s in Table 8 must be present and must maximize within the same two seconds.


16.2 The signal-to-noise ratio (S/N) for the GC peak at each exact m/z must be greater than or equal to 2.5 for each CDD or CDF detected in a sample extract, and greater than or equal to 10 for all CDDs/CDFs in the calibration standard (Sections 10.2.3 and 15.3.3).


16.3 The ratio of the integrated areas of the two exact m/z’s specified in Table 8 must be within the limit in Table 9, or within ±10% of the ratio in the midpoint (CS3) calibration or calibration verification (VER), whichever is most recent.


16.4 The relative retention time of the peak for a 2,3,7,8-substituted CDD or CDF must be within the limit in Table 2. The retention time of peaks representing non-2,3,7,8-substituted CDDs/CDFs must be within the retention time windows established in Section 10.3.


16.5 Confirmatory Analysis—Isomer specificity for 2,3,7,8-TCDF cannot be achieved on the DB-5 column. Therefore, any sample in which 2,3,7,8-TCDF is identified by analysis on a DB-5 column must have a confirmatory analysis performed on a DB-225, SP-2330, or equivalent GC column. The operating conditions in Section 10.1.1 may be adjusted to optimize the analysis on the second GC column, but the GC/MS must meet the mass resolution and calibration specifications in Section 10.


16.6 If the criteria for identification in Sections 16.1 through 16.5 are not met, the CDD or CDF has not been identified and the results may not be reported for regulatory compliance purposes. If interferences preclude identification, a new aliquot of sample must be extracted, further cleaned up, and analyzed.


17.0 Quantitative Determination


17.1 Isotope Dilution Quantitation—By adding a known amount of a labeled compound to every sample prior to extraction, correction for recovery of the CDD/CDF can be made because the CDD/CDF and its labeled analog exhibit similar effects upon extraction, concentration, and gas chromatography. Relative response (RR) values are used in conjunction with the initial calibration data described in Section 10.5 to determine concentrations directly, so long as labeled compound spiking levels are constant, using the following equation:



where:

Cex = The concentration of the CDD/CDF in the extract, and the other terms are as defined in Section 10.5.2.

17.1.1 Because of a potential interference, the labeled analog of OCDF is not added to the sample. Therefore, OCDF is quantitated against labeled OCDD. As a result, the concentration of OCDF is corrected for the recovery of the labeled OCDD. In instances where OCDD and OCDF behave differently during sample extraction, concentration, and cleanup procedures, this may decrease the accuracy of the OCDF results. However, given the low toxicity of this compound relative to the other dioxins and furans, the potential decrease in accuracy is not considered significant.


17.1.2 Because
13C12-1,2,3,7,8,9-HxCDD is used as an instrument internal standard (i.e., not added before extraction of the sample), it cannot be used to quantitate the 1,2,3,7,8,9-HxCDD by strict isotope dilution procedures. Therefore, 1,2,3,7,8,9-HxCDD is quantitated using the averaged response of the labeled analogs of the other two 2,3,7,8-substituted HxCDD’s: 1,2,3,4,7,8-HxCDD and 1,2,3,6,7,8-HxCDD. As a result, the concentration of 1,2,3,7,8,9-HxCDD is corrected for the average recovery of the other two HxCDD’s.


17.1.3 Any peaks representing non-2,3,7,8-substituted CDDs/CDFs are quantitated using an average of the response factors from all of the labeled 2,3,7,8-isomers at the same level of chlorination.


17.2 Internal Standard Quantitation and Labeled Compound Recovery.


17.2.1 Compute the concentrations of 1,2,3,7,8,9-HxCDD, OCDF, the
13C-labeled analogs and the
37C-labeled cleanup standard in the extract using the response factors determined from the initial calibration data (Section 10.6) and the following equation:



where:

Cex = The concentration of the CDD/CDF in the extract, and the other terms are as defined in Section 10.6.1.


Note:

There is only one m/z for the
37Cl-labeled standard.


17.2.2 Using the concentration in the extract determined above, compute the percent recovery of the
13C-labeled compounds and the
37C-labeled cleanup standard using the following equation:



17.3 The concentration of a CDD/CDF in the solid phase of the sample is computed using the concentration of the compound in the extract and the weight of the solids (Section 11.5.1), as follows:



where:

Cex = The concentration of the compound in the extract.

Vex = The extract volume in mL.

Ws = The sample weight (dry weight) in kg.

17.4 The concentration of a CDD/CDF in the aqueous phase of the sample is computed using the concentration of the compound in the extract and the volume of water extracted (Section 11.4 or 11.5), as follows:



where:

Cex = The concentration of the compound in the extract.

Vex = The extract volume in mL.

Vs = The sample volume in liters.

17.5 If the SICP area at either quantitation m/z for any compound exceeds the calibration range of the system, a smaller sample aliquot is extracted.


17.5.1 For aqueous samples containing 1% solids or less, dilute 100 mL, 10 mL, etc., of sample to 1 L with reagent water and re-prepare, extract, clean up, and analyze per Sections 11 through 14.


17.5.2 For samples containing greater than 1% solids, extract an amount of sample equal to
1/10,
1/100, etc., of the amount used in Section 11.5.1. Re-prepare, extract, clean up, and analyze per Sections 11 through 14.


17.5.3 If a smaller sample size will not be representative of the entire sample, dilute the sample extract by a factor of 10, adjust the concentration of the instrument internal standard to 100 pg/µL in the extract, and analyze an aliquot of this diluted extract by the internal standard method.


17.6 Results are reported to three significant figures for the CDDs/CDFs and labeled compounds found in all standards, blanks, and samples.


17.6.1 Reporting units and levels.


17.6.1.1 Aqueous samples—Report results in pg/L (parts-per-quadrillion).


17.6.1.2 Samples containing greater than 1% solids (soils, sediments, filter cake, compost)—Report results in ng/kg based on the dry weight of the sample. Report the percent solids so that the result may be corrected.


17.6.1.3 Tissues—Report results in ng/kg of wet tissue, not on the basis of the lipid content of the sample. Report the percent lipid content, so that the data user can calculate the concentration on a lipid basis if desired.


17.6.1.4 Reporting level.


17.6.1.4.1 Standards (VER, IPR, OPR) and samples—Report results at or above the minimum level (Table 2). Report results below the minimum level as not detected or as required by the regulatory authority.


17.6.1.4.2 Blanks—Report results above one-third the ML.


17.6.2 Results for CDDs/CDFs in samples that have been diluted are reported at the least dilute level at which the areas at the quantitation m/z’s are within the calibration range (Section 17.5).


17.6.3 For CDDs/CDFs having a labeled analog, results are reported at the least dilute level at which the area at the quantitation m/z is within the calibration range (Section 17.5) and the labeled compound recovery is within the normal range for the method (Section 9.3 and Tables 6, 6a, 7, and 7a).


17.6.4 Additionally, if requested, the total concentration of all isomers in an individual level of chlorination (i.e., total TCDD, total TCDF, total Paced, etc.) may be reported by summing the concentrations of all isomers identified in that level of chlorination, including both 2,3,7,8-substituted and non-2,3,7,8-substituted isomers.


18.0 Analysis of Complex Samples

18.1 Some samples may contain high levels (>10 ng/L; >1000 ng/kg) of the compounds of interest, interfering compounds, and/or polymeric materials. Some extracts will not concentrate to 10 µL (Section 12.7); others may overload the GC column and/or mass spectrometer.


18.2 Analyze a smaller aliquot of the sample (Section 17.5) when the extract will not concentrate to 10 µL after all cleanup procedures have been exhausted.


18.3 Chlorodiphenyl Ethers—If chromatographic peaks are detected at the retention time of any CDDs/CDFs in any of the m/z channels being monitored for the chlorodiphenyl ethers (Table 8), cleanup procedures must be employed until these interferences are removed. Alumina (Section 13.4) and Florisil (Section 13.8) are recommended for removal of chlorodiphenyl ethers.


18.4 Recovery of Labeled Compounds—In most samples, recoveries of the labeled compounds will be similar to those from reagent water or from the alternate matrix (Section 7.6).


18.4.1 If the recovery of any of the labeled compounds is outside of the normal range (Table 7), a diluted sample shall be analyzed (Section 17.5).


18.4.2 If the recovery of any of the labeled compounds in the diluted sample is outside of normal range, the calibration verification standard (Section 7.13) shall be analyzed and calibration verified (Section 15.3).


18.4.3 If the calibration cannot be verified, a new calibration must be performed and the original sample extract reanalyzed.


18.4.4 If the calibration is verified and the diluted sample does not meet the limits for labeled compound recovery, the method does not apply to the sample being analyzed and the result may not be reported for regulatory compliance purposes. In this case, alternate extraction and cleanup procedures in this method must be employed to resolve the interference. If all cleanup procedures in this method have been employed and labeled compound recovery remains outside of the normal range, extraction and/or cleanup procedures that are beyond this scope of this method will be required to analyze these samples.


19.0 Pollution Prevention

19.1 The solvents used in this method pose little threat to the environment when managed properly. The solvent evaporation techniques used in this method are amenable to solvent recovery, and it is recommended that the laboratory recover solvents wherever feasible.


19.2 Standards should be prepared in volumes consistent with laboratory use to minimize disposal of standards.


20.0 Waste Management

20.1 It is the laboratory’s responsibility to comply with all federal, state, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restrictions, and to protect the air, water, and land by minimizing and controlling all releases from fume hoods and bench operations. Compliance is also required with any sewage discharge permits and regulations.


20.2 Samples containing HCl to pH

20.3 The CDDs/CDFs decompose above 800 °C. Low-level waste such as absorbent paper, tissues, animal remains, and plastic gloves may be burned in an appropriate incinerator. Gross quantities (milligrams) should be packaged securely and disposed of through commercial or governmental channels that are capable of handling extremely toxic wastes.


20.4 Liquid or soluble waste should be dissolved in methanol or ethanol and irradiated with ultraviolet light with a wavelength shorter than 290 nm for several days. Use F40 BL or equivalent lamps. Analyze liquid wastes, and dispose of the solutions when the CDDs/CDFs can no longer be detected.


20.5 For further information on waste management, consult “The Waste Management Manual for Laboratory Personnel” and “Less is Better—Laboratory Chemical Management for Waste Reduction,” available from the American Chemical Society’s Department of Government Relations and Science Policy, 1155 16th Street N.W., Washington, D.C. 20036.


21.0 Method Performance

Method performance was validated and performance specifications were developed using data from EPA’s international interlaboratory validation study (References 30-31) and the EPA/paper industry Long-Term Variability Study of discharges from the pulp and paper industry (58 FR 66078).


22.0 References

1. Tondeur, Yves. “Method 8290: Analytical Procedures and Quality Assurance for Multimedia Analysis of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans by High Resolution Gas Chromatography/High Resolution Mass Spectrometry,” USEPA EMSL, Las Vegas, Nevada, June 1987.


2. “Measurement of 2,3,7,8-Tetrachlorinated Dibenzo-p-dioxin (TCDD) and 2,3,7,8-Tetrachlorinated Dibenzofuran (TCDF) in Pulp, Sludges, Process Samples and Wastewaters from Pulp and Paper Mills,” Wright State University, Dayton, OH 45435, June 1988.


3. “NCASI Procedures for the Preparation and Isomer Specific Analysis of Pulp and Paper Industry Samples for 2,3,7,8-TCDD and 2,3,7,8-TCDF,” National Council of the Paper Industry for Air and Stream Improvement Inc., 260 Madison Avenue, New York, NY 10016, Technical Bulletin No. 551, Pre-Release Copy, July 1988.


4. “Analytical Procedures and Quality Assurance Plan for the Determination of PCDD/PCDF in Fish,” USEPA, Environmental Research Laboratory, 6201 Congdon Boulevard, Duluth, MN 55804, April 1988.


5. Tondeur, Yves. “Proposed GC/MS Methodology for the Analysis of PCDDs and PCDFs in Special Analytical Services Samples,” Triangle Laboratories, Inc., 801-10 Capitola Dr, Research Triangle Park, NC 27713, January 1988; updated by personal communication September 1988.


6. Lamparski, L.L. and Nestrick, T.J. “Determination of Tetra-, Hexa-, Hepta-, and Octachlorodibenzo-p-dioxin Isomers in Particulate Samples at Parts per Trillion Levels,” Analytical Chemistry, 52: 2045-2054, 1980.


7. Lamparski, L.L. and Nestrick, T.J. “Novel Extraction Device for the Determination of Chlorinated Dibenzo-p-dioxins (PCDDs) and Dibenzofurans (PCDFs) in Matrices Containing Water,” Chemosphere, 19:27-31, 1989.


8. Patterson, D.G., et. al. “Control of Interferences in the Analysis of Human Adipose Tissue for 2,3,7,8-Tetrachlorodibenzo-p-dioxin,” Environmental Toxicological Chemistry, 5:355-360, 1986.


9. Stanley, John S. and Sack, Thomas M. “Protocol for the Analysis of 2,3,7,8-Tetrachlorodibenzo-p-dioxin by High Resolution Gas Chromatography/High Resolution Mass Spectrometry,” USEPA EMSL, Las Vegas, Nevada 89114, EPA 600/4-86-004, January 1986.


10. “Working with Carcinogens,” Department of Health, Education, & Welfare, Public Health Service, Centers for Disease Control, NIOSH, Publication 77-206, August 1977, NTIS PB-277256.


11. “OSHA Safety and Health Standards, General Industry,” OSHA 2206, 29 CFR 1910.


12. “Safety in Academic Chemistry Laboratories,” ACS Committee on Chemical Safety, 1979.


13. “Standard Methods for the Examination of Water and Wastewater,” 18th edition and later revisions, American Public Health Association, 1015 15th St, N.W., Washington, DC 20005, 1-35: Section 1090 (Safety), 1992.


14. “Method 613—2,3,7,8-Tetrachlorodibenzo-p-dioxin,” 40 CFR 136 (49 FR 43234), October 26, 1984, Section 4.1.


15. Provost, L.P. and Elder, R.S. “Interpretation of Percent Recovery Data,” American Laboratory, 15: 56-83, 1983.


16. “Standard Practice for Sampling Water,” ASTM Annual Book of Standards, ASTM, 1916 Race Street, Philadelphia, PA 19103-1187, 1980.


17. “Methods 330.4 and 330.5 for Total Residual Chlorine,” USEPA, EMSL, Cincinnati, OH 45268, EPA 600/4-79-020, March 1979.


18. “Handbook of Analytical Quality Control in Water and Wastewater Laboratories,” USEPA EMSL, Cincinnati, OH 45268, EPA-600/4-79-019, March 1979.


19. Williams, Rick. Letter to Bill Telliard, June 4, 1993, available from the EPA Sample Control Center operated by DynCorp Viar, Inc., 300 N Lee St, Alexandria, VA 22314, 703-519-1140.


20. Barkowski, Sarah. Fax to Sue Price, August 6, 1992, available from the EPA Sample Control Center operated by DynCorp Viar, Inc., 300 N Lee St, Alexandria VA 22314, 703-519-1140.


21. “Analysis of Multi-media, Multi-concentration Samples for Dioxins and Furans, PCDD/PCDF Analyses Data Package”, Narrative for Episode 4419, MRI Project No. 3091-A, op.cit. February 12, 1993, Available from the EPA Sample Control Center operated by DynCorp Viar Inc, 300 N Lee St, Alexandria, VA 22314 (703-519-1140).


22. “Analytical Procedures and Quality Assurance Plan for the Determination of PCDD/PCDF in Fish”, U.S. Environmental Protection Agency, Environmental Research Laboratory, Duluth, MN 55804, EPA/600/3-90/022, March 1990.


23. Afghan, B.K., Carron, J., Goulden, P.D., Lawrence, J., Leger, D., Onuska, F., Sherry, J., and Wilkenson, R.J., “Recent Advances in Ultratrace Analysis of Dioxins and Related Halogenated Hydrocarbons”, Can J. Chem., 65: 1086-1097, 1987.


24. Sherry, J.P. and Tse, H. “A Procedure for the Determination of Polychlorinated Dibenzo-p-dioxins in Fish”, Chemosphere, 20: 865-872, 1990.


25. “Preliminary Fish Tissue Study”, Results of Episode 4419, available from the EPA Sample Control Center operated by DynCorp Viar, Inc., 300 N Lee St, Alexandria, VA 22314, 703-519-1140.


26. Nestrick, Terry L. DOW Chemical Co., personal communication with D.R. Rushneck, April 8, 1993. Details available from the U.S. Environmental Protection Agency Sample Control Center operated by DynCorp Viar Inc, 300 N Lee St, Alexandria, VA 22314, 703-519-1140.


27. Barnstadt, Michael. “Big Fish Column”, Triangle Laboratories of RTP, Inc., SOP 129-90, 27 March 27, 1992.


28. “Determination of Polychlorinated Dibenzo-p-Dioxins (PCDD) and Dibenzofurans (PCDF) in Environmental Samples Using EPA Method 1613”, Chemical Sciences Department, Midwest Research Institute, 425 Volker Boulevard, Kansas City, MO 44110-2299, Standard Operating Procedure No. CS-153, January 15, 1992.


29. Ryan, John J. Raymonde Lizotte and William H. Newsome, J. Chromatog. 303 (1984) 351-360.


30. Telliard, William A., McCarty, Harry B., and Riddick, Lynn S. “Results of the Interlaboratory Validation Study of USEPA Method 1613 for the Analysis of Tetra-through Octachlorinated Dioxins and Furans by Isotope Dilution GC/MS,” Chemosphere, 27, 41-46 (1993).


31. “Results of the International Interlaboratory Validation Study of USEPA Method 1613”, October 1994, available from the EPA Sample Control Center operated by DynCorp Viar, Inc., 300 N Lee St, Alexandria, VA 22314, 703-519-1140.


23.0 Tables and Figures

Table 1—Chlorinated Dibenzo-p-Dioxins and Furans Determined by Isotope Dilution and Internal Standard High Resolution Gas Chromatography (HRGC)/High Resolution Mass Spectrometry (HRMS)

CDDs/CDFs
1
CAS registry
Labeled analog
CAS registry
2,3,7,8-TCDD1746-01-6
13C12-2,3,7,8-TCDD

37Cl4-2,3,7,8-TCDD		76523-40-5

85508-50-5
Total TCDD41903-57-5
2,3,7,8-TCDF51207-31-9
13C12-2,3,7,8-TCDF		89059-46-1
Total-TCDF55722-27-5
1,2,3,7,8-PeCDD40321-76-4
13C12-1,2,3,7,8-PeCDD		109719-79-1
Total-PeCDD36088-22-9
1,2,3,7,8-PeCDF57117-41-6
13C12-1,2,3,7,8-PeCDF		109719-77-9
2,3,4,7,8-PeCDF57117-31-4
13C12-2,3,4,7,8-PeCDF		116843-02-8
Total-PeCDF30402-15-4
1,2,3,4,7,8-HxCDD39227-28-6
13C12-1,2,3,4,7,8-HxCDD		109719-80-4
1,2,3,6,7,8-HxCDD57653-85-7
13C12-1,2,3,6,7,8-HxCDD		109719-81-5
1,2,3,7,8,9-HxCDD19408-74-3
13C12-1,2,3,7,8,9-HxCDD		109719-82-6
Total-HxCDD34465-46-8
1,2,3,4,7,8-HxCDF70648-26-9
13C12-1,2,3,4,7,8-HxCDF		114423-98-2
1,2,3,6,7,8-HxCDF57117-44-9
13C12-1,2,3,6,7,8-HxCDF		116843-03-9
1,2,3,7,8,9-HxCDF72918-21-9
13C12-1,2,3,7,8,9-HxCDF		116843-04-0
2,3,4,6,7,8-HxCDF60851-34-5
13C12-2,3,4,6,7,8-HxCDF		116843-05-1
Total-HxCDF55684-94-1
1,2,3,4,6,7,8-HpCDD35822-46-9
13C12-1,2,3,4,6,7,8-HpCDD		109719-83-7
Total-HpCDD37871-00-4
1,2,3,4,6,7,8-HpCDF67562-39-4
13C12-1,2,3,4,6,7,8-HpCDF		109719-84-8
1,2,3,4,7,8,9-HpCDF55673-89-7
13C12-1,2,3,4,7,8,9-HpCDF		109719-94-0
Total-HpCDF38998-75-3
OCDD3268-87-9
13C12-OCDD		114423-97-1
OCDF39001-02-0Not used


1 Chlorinated dibenzo-p-dioxins and chlorinated dibenzofurans.

TCDD = Tetrachlorodibenzo-p-dioxin.

TCDF = Tetrachlorodibenzofuran.

PeCDD = Pentachlorodibenzo-p-dioxin.

PeCDF = Pentachlorodibenzofuran.

HxCDD = Hexachlorodibenzo-p-dioxin.

HxCDF = Hexachlorodibenzofuran.

HpCDD = Heptachlorodibenzo-p-dioxin.

HpCDF = Heptachlorodibenzofuran.

OCDD = Octachlorodibenzo-p-dioxin.

OCDF = Octachlorodibenzofuran.


Table 2—Retention Time References, Quantitation References, Relative Retention Times, and Minimum Levels for CDDS and DCFS

CDD/CDF
Retention time and quantitation

reference
Relative retention time
Minimum level
1
Water (pg/L; ppq)
Solid (ng/kg; ppt)
Extract (pg/µL; ppb)
Compounds using
13 C12-1,2,3,4-TCDD as the Injection Internal Standard
2,3,7,8-TCDF
13 C12-2,3,7,8-TCDF		0.999-1.0031010.5
2,3,7,8-TCDD
13 C12-2,3,7,8-TCDD		0.999-1.0021010.5
1,2,3,7,8-Pe
13 C12-1,2,3,7,8-PeCDF		0.999-1.0025052.5
2,3,4,7,8-PeCDF
13 C12-2,3,4,7,8-PeCDF		0.999-1.0025052.5
1,2,3,7,8-PeCDD
13 C12-1,2,3,7,8-PeCDD		0.999-1.0025052.5

13 C12-2,3,7,8-TCDF
13 C12-1,2,3,4-TCDD		0.923-1.103

13 C12-2,3,7,8-TCDD
13 C12-1,2,3,4-TCDD		0.976-1.043

13 C12-2,3,7,8-TCDD
13 C12-1,2,3,4-TCDD		0.989-1.052

13 C12-1,2,3,7,8-PeCDF
13 C12-1,2,3,4-TCDD		1.000-1.425

13 C12-2,3,4,7,8-PeCDF
13 C12-1,2,3,4-TCDD		1.001-1.526

13 C12-1,2,3,7,8-PeCDF
13 C12-1,2,3,4-TCDD		1.000-1.567
Compounds using
13 C12-1,2,3,7,8,9-HxCDD as the Injection Internal Standard
1,2,3,4,7,8-HxCDF
13 C12-1,2,3,4,7,8-HxCDF		0.999-1.0015052.5
1,2,3,6,7,8-HxCDF
13 C12-1,2,3,6,7,8-HxCDF		0.997-1.0055052.5
1,2,3,7,8,9-HxCDF
13 C12-1,2,3,7,8,9-HxCDF		0.999-1.0015052.5
2,3,4,6,7,8-HxCDF
13 C12-2,3,4,6,7,8-HxCDF		0.999-1.0015052.5
1,2,3,4,7,8-HxCDD
13 C12-1,2,3,4,7,8-HxCDD		0.999-1.0015052.5
1,2,3,6,7,8-HxCDD
13 C12-1,2,3,6,7,8-HxCDD		0.998-1.0045052.5
1,2,3,7,8,9-HxCDD(
2)		1.000-1.0195052.5
1,2,3,4,6,7,8-HpCDF
13 C12-1,2,3,4,6,7,8-HpCDF		0.999-1.0015052.5
1,2,3,4,7,8,9-HpCDF
13 C12-1,2,3,4,7,8,9-HpCDF		0.999-1.0015052.5
1,2,3,4,6,7,8-HpCDD
13 C12-1,2,3,4,6,7,8-HpCDD		0.999-1.0015052.5
OCDF
13 C12-OCDD		0.999-1.001100105.0
OCDD
13 C12-OCDD		0.999-1.001100105.0
1,2,3,4,6,7,8,-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		0.949-0.975

13 C121,2,3,7,8,9-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		0.977-1.047

13 C122,3,4,6,7,8,-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		0.959-1.021

13 C121,2,3,4,7,8,-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		0.977-1.000

13 C121,2,3,6,7,8,-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		0.981-1.003

13 C121,2,3,4,6,7,8-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		1.043-1.085

13 C121,2,3,4,7,8,9-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		1.057-1.151

13 C121,2,3,4,6,7,8-HxCDF
13 C12-1,2,3,7,8,9-HpCDD		1.086-1.110

13 C12OCDD
13 C12-1,2,3,7,8,9-HpCDD		1.032-1.311


1 The Minimum Level (ML) for each analyte is defined as the level at which the entire analytical system must give a recognizable signal and acceptable calibration point. It is equivalent to the concentration of the lowest calibration standard, assuming that all method-specified sample weights, volumes, and cleanup procedures have been employed.


2 The retention time reference for 1,2,3,7,8,9-HxCDD is
13C12-1,2,3,6,7,8-HxCDD, and 1,2,3,7,8,9-HxCDD is quantified using the averaged responses for
13C12-1,2,3,4,7,8-HxCDD and
13C12-1,2,3,6,7,8-HxCDD.


Table 3—Concentration of Stock and Spiking Solutions Containing CDDS/CDFS and Labeled Compounds

CDD/CDF
Labeled compound stock solution
1

(ng/mL)
Labeled compound spiking solution
2

(ng/mL)
PAR stock solution
3 (ng/mL)
PAR spiking solution
4

(ng/mL)
2,3,7,8-TCDD400.8
2,3,7,8-TCDF400.8
1,2,3,7,8-PeCDD2004
1,2,3,7,8-PeCDF2004
2,3,4,7,8-PeCDF2004
1,2,3,4,7,8-HxCDD2004
1,2,3,6,7,8-HxCDD2004
1,2,3,7,8,9-HxCDD2004
1,2,3,4,7,8-HxCDF2004
1,2,3,6,7,8-HxCDF2004
1,2,3,7,8,9-HxCDF2004
2,3,4,6,7,8-HxCDF2004
1,2,3,4,6,7,8-HpCDD2004
1,2,3,4,6,7,8-HpCDF2004
1,2,3,4,7,8,9-HpCDF2004
OCDD4008
OCDF4008

13C12-2,3,7,8-TCDD		1002

13C12-2,3,7,8-TCDF		1002

13C12-1,2,3,7,8-PeCDD		1002

13C12-1,2,3,7,8-PeCDF		1002

13C12-2,3,4,7,8-PeCDF		1002

13C12-1,2,3,4,7,8-HxCDD		1002

13C12-1,2,3,6,7,8-HxCDD		1002

13C12-1,2,3,4,7,8-HxCDF		1002

13C12-1,2,3,6,7,8-HxCDF		1002

13C12-1,2,3,7,8,9-HxCDF		1002

13C12-2,3,4,6,7,8-HxCDF		1002

13C12-1,2,3,4,6,7,8-HpCDD		1002

13C12-1,2,3,4,6,7,8-HpCDF		1002

13C12-1,2,3,4,7,8,9-HpCDF		1002

13C12-OCDD		2004
Cleanup Standard
5

37Cl4-2,3,7,8-TCDD		0.8
Internal Standards
6

13C12-1,2,3,4-TCDD		200

13C12-1,2,3,7,8,9-HxCDD		200


1 Section 7.10—prepared in nonane and diluted to prepare spiking solution.


2 Section 7.10.3—prepared in acetone from stock solution daily.


3 Section 7.9—prepared in nonane and diluted to prepare spiking solution.


4 Section 7.14—prepared in acetone from stock solution daily.


5 Section 7.11—prepared in nonane and added to extract prior to cleanup.


6 Section 7.12—prepared in nonane and added to the concentrated extract immediately prior to injection into the GC (Section 14.2).


Table 4—Concentration of CDDS/CDFS in Calibration and Calibration Verification Solutions
1 (Section 15.3)


CDD/CDF
CS2

(ng/mL)
CS3

(ng/mL)
CS4

(ng/mL)
CS5

(ng/mL)
2,3,7,8-TCDD0.521040200
2,3,7,8-TCDF0.521040200
1,2,3,7,8-PeCDD2.510502001000
1,2,3,7,8-PeCDF2.510502001000
2,3,4,7,8-PeCDF2.510502001000
1,2,3,4,7,8-HxCDD2.510502001000
1,2,3,6,7,8-HxCDD2.510502001000
1,2,3,7,8,9-HxCDD2.510502001000
1,2,3,4,7,8-HxCDF2.510502001000
1,2,3,6,7,8-HxCDF2.510502001000
1,2,3,7,8,9-HxCDF2.510502001000
2,3,4,6,7,8-HxCDF2.510502001000
1,2,3,4,6,7,8-HpCDD2.510502001000
1,2,3,4,6,7,8-HpCDF2.510502001000
1,2,3,4,7,8,9-HpCDF2.510502001000
OCDD5.0201004002000
OCDF5.0201004002000

13 C12-2,3,7,8-TCDD		100100100100100

13 C12-2,3,7,8-TCDF		100100100100100

13 C12-1,2,3,7,8-PeCDD		100100100100100

13 C12-PeCDF		100100100100100

13 C12-2,3,4,7,8-PeCDF		100100100100100

13 C12-1,2,3,4,7,8-HxCDD		100100100100100

13 C12-1,2,3,6,7,8-HxCDD		100100100100100

13 C12-1,2,3,4,7,8-HxCDF		100100100100100

13 C12-1,2,3,6,7,8-HxCDF		100100100100100

13 C12-1,2,3,7,8,9-HxCDF		100100100100100

13 C12-1,2,3,4,6,7,8-HpCDD		100100100100100

13 C12-1,2,3,4,6,7,8-HpCDF		100100100100100

13 C12-1,2,3,4,7,8,9-Hp CDF		100100100100100

13 C12-OCDD		200200200200200
Cleanup Standard:

37 C14-2,3,7,8-TCDD		0.521040200
Internal Standards:

13 C12-1,2,3,4-TCDD		100100100100100

13 C12-1,2,3,7,8,9-HxCDD		100100100100100

Table 5—GC Retention Time Window Defining Solution and Isomer Specificity Test Standard (Section 7.15)

DB-5 column GC retention-time window defining solution
CDD/CDF
First eluted
Last eluted
TCDF1,3,6,8-1,2,8,9-
TCDD1,3,6,8-1,2,8,9-
PeCDF1,3,4,6,8-1,2,3,8,9-
PeCDD1,2,4,7,9-1,2,3,8,9-
HxCDF1,2,3,4,6,8-1,2,3,4,8,9-
HxCDD1,2,4,6,7,9-1,2,3,4,6,7-
HpCDF1,2,3,4,6,7,8-1,2,3,4,7,8,9-
HpCDD1,2,3,4,6,7,9-1,2,3,4,6,7,8-

DB-5 Column TCDD Specificity Test Standard
1,2,3,7 = 1,2,3,8-TCDD
2,3,7,8-TCDD
1,2,3,9-TCDD
DB-225 Column TCDF Isomer Specificity Test Standard
2,3,4,7-TCDF
2,3,7,8-TCDF
1,2,3,9-TCDF

Table 6—Acceptance Criteria for Performance Tests When All CDDS/CDFS Are Tested
1

CDD/CDF
Test conc. (ng/mL)
IPR
2 3
OPR

(ng/mL)
VER

(ng/mL)
s

(ng/mL)
X

(ng/mL)
2,3,7,8-TCDD102.88.3-12.96.7-15.87.8-12.9
2,3,7,8-TCDF102.08.7-13.77.5-15.88.4-12.0
1,2,3,7,8-PeCDD507.538-6635-7139-65
1,2,3,7,8-PeCDF507.543-6240-6741-60
2,3,4,7,8-PeCDF508.636-7534-8041-61
1,2,3,4,7,8-HxCDD509.439-7635-8239-64
1,2,3,6,7,8-HxCDD507.742-6238-6739-64
1,2,3,7,8,9-HxCDD5011.137-7132-8141-61
1,2,3,4,7,8-HxCDF508.741-5936-6745-56
1,2,3,6,7,8-HxCDF506.746-6042-6544-57
1,2,3,7,8,9-HxCDF506.442-6139-6545-56
2,3,4,6,7,8-HxCDF507.437-7435-7844-57
1,2,3,4,6,7,8-HpCDD507.738-6535-7043-58
1,2,3,4,6,7,8-HpCDF506.345-5641-6145-55
1,2,3,4,7,8,9-HpCDF508.143-6339-6943-58
OCDD1001989-12778-14479-126
OCDF1002774-14663-17063-159

13C12-2,3,7,8-TCDD		1003728-13420-17582-121

13C12-2,3,7,8-TCDF		1003531-11322-15271-140

13C12-1,2,3,7,8-PeCDD		1003927-18421-22762-160

13C12-1,2,3,7,8-PeCDF		1003427-15621-19276-130

13C12-2,3,4,7,8-PeCDF		1003816-27913-32877-130

13C12-1,2,3,4,7,8-HxCDD		1004129-14721-19385-117

13C12-1,2,3,6,7,8-HxCDD		1003834-12225-16385-118

13C12-1,2,3,4,7,8-HxCDF		1004327-15219-20276-131

13C12-1,2,3,6,7,8-HxCDF		1003530-12221-15970-143

13C12-1,2,3,7,8,9-HxCDF		1004024-15717-20574-135

13C12-2,3,4,6,7,8,-HxCDF		1003729-13622-17673-137

13C12-1,2,3,4,6,7,8-HpCDD		1003534-12926-16672-138

13C12-1,2,3,4,6,7,8-HpCDF		1004132-11021-15878-129

13C12-1,2,3,4,7,8,9-HpCDF		1004028-14120-18677-129

13C12-OCDD		2009541-27626-39796-415

37Cl4-2,3,7,8-TCDD		103.63.9-15.43.1-19.17.9-12.7


1 All specifications are given as concentration in the final extract, assuming a 20 µL volume.


2 s = standard deviation of the concentration.


3 X = average concentration.


Table 6a—Acceptance Criteria for Performance Tests When Only Tetra Compounds are Tested
1

CDD/CDF
Test Conc. (ng/mL)
IPR
2 3
OPR

(ng/mL)
VER

(ng/mL)
s (ng/mL)
X (ng/mL)
2,3,7,8-TCDD102.78.7-12.47.314.68.2-12.3
2,3,7,8-TCDF102.09.1-13.18.0-14.78.6-11.6

13C12-2,3,7,8-TCDD		1003532-11525-14185-117

13C12-2,3,7,8-TCDF		1003435-9926-12676-131

37Cl4-2,3,7,8-TCDD		103.44.5-13.43.7-15.88.3-12.1


1 All specifications are given as concentration in the final extract, assuming a 20 µL volume.


2 s = standard deviation of the concentration.


3 X = average concentration.


Table 7—Labeled Compounds Recovery in Samples When all CDDS/CDFS are Tested

Compound
Test conc. (ng/mL)
Labeled compound

recovery
(ng/mL)
1
(%)

13C12-2,3,7,8-TCDD		10025-16425-164

13C12-2,3,7,8-TCDF		10024-16924-169

13C12-1,2,3,7,8-PeCDD		10025-18125-181

13C12-1,2,3,7,8-PeCDF		10024-18524-185

13C12-2,3,4,7,8-PeCDF		10021-17821-178

13C12-1,2,3,4,7,8-HxCDD		10032-14132-141

13C12-1,2,3,6,7,8-HxCDD		10028-13028-130

13C12-1,2,3,4,7,8-HxCDF		10026-15226-152

13C12-1,2,3,6,7,8-HxCDF		10026-12326-123

13C12-1,2,3,7,8,9-HxCDF		10029-14729-147

13C12-2,3,4,6,7,8-HxCDF		10028-13628-136

13C12-1,2,3,4,6,7,8-HpCDD		10023-14023-140

13C12-1,2,3,4,6,7,8-HpCDF		10028-14328-143

13C12-1,2,3,4,7,8,9-HpCDF		10026-13826-138

13C12-OCDD		20034-31317-157

37Cl4-2,3,7,8-TCDD		103.5-19.735-197


1 Specification given as concentration in the final extract, assuming a 20-µL volume.


Table 7a—Labeled Compound Recovery in Samples When Only Tetra Compounds are Tested

Compound
Test conc. (ng/mL)
Labeled compound

recovery
(ng/mL)
1
(%)

13C12-2,3,7,8-TCDD		10031-13731-137

13C12-2,3,7,8-TCDF		10029-14029-140

37Cl4-2,3,7,8-TCDD		104.2-16.442-164


1 Specification given as concentration in the final extract, assuming a 20 µL volume.


Table 8—Descriptors, Exact M/Z’s, M/Z Types, and Elemental Compositions of the CDDs and CDFs

Descriptor
Exact M/Z
1
M/Z type
Elemental composition
Substance
2
1292.9825LockC7F11PFK
303.9016MC12H4
35Cl4O		TCDF
305.8987M = 2C12H4
35Cl3
37ClO		TCDF
315.9419M
13C12H4
35Cl4O		TCDF
3
317.9389M = 2
13C12H4
35Cl3
37ClO		TCDF
3
319.8965MC12H4
35Cl4O2		TCDD
321.8936M = 2C12H4
35Cl3
37ClO2		TCDD
327.8847MC12H4
37Cl4O2		TCDD
4
330.9792QCC7F13PFK
331.9368M
13C12H4
35Cl4O2		TCDD
3
333.9339M = 2
13C12H4
35Cl3
37ClO2		TCDD
3
375.8364M = 2C12H4
35Cl5
37ClO		HxCDPE
2339.8597M = 2C12H3
35Cl4
37ClO		PeCDF
341.8567M = 4C12H3
35Cl3
37Cl2O		PeCDF
351.9000M = 2
13C12H3
35Cl4
37ClO		PeCDF
353.8970M = 4
13C12H3
35Cl3
37Cl2O		PeCDF
3
354.9792LockC9F13PFK
355.8546M = 2C12H3
35Cl4
37ClO2		PeCDD
357.8516M = 4C12H3
35Cl3
37Cl2O2		PeCDD
367.8949M = 2
13C12H3
35Cl4
37ClO2		PeCDD
3
369.8919M = 4
13C12H3
35Cl3
37Cl2O2		PeCDD
3
409.7974M = 2C12H3
35Cl6
37ClO		HpCDPE
3373.8208M = 2C12H2
35Cl5
37ClO		HxCDF
375.8178M = 4C12H2
35Cl4
37Cl2O		HxCDF
383.8639M
13C12H2
35Cl6O		HxCDF
3
385.8610M = 2
13C12H2
35Cl5
37ClO		HxCDF
3
389.8157M = 2C12H2
35Cl5
37ClO2		HxCDD
391.8127M = 4C12H2
35Cl4
37Cl2O2		HxCDD
392.9760LockC9F15PFK
401.8559M = 2
13C12H2
35Cl5
37ClO2		HxCDD
3
403.8529M = 4
13C12H2
35Cl4
37Cl2O2		HxCDD
3
430.9729QCC9F17PFK
445.7555M = 4C12H2
35Cl6
37Cl2O		OCDPE
4407.7818M = 2C12H
35Cl6
37ClO		HpCDF
409.7789M = 4C12H
35Cl5
37Cl2O		HpCDF
417.8253M
13C12H
35Cl7O		HpCDF
3
419.8220M = 2
13C12H
35Cl6
37ClO		HpCDF
3
423.7766M = 2C12H
35Cl6
37ClO2		HpCDD
425.7737M = 4C12H
35Cl5
37Cl2O2		HpCDD
430.9729LockC9F17PFK
435.8169M = 2
13C12H
35Cl6
37ClO2		HpCDD
3
437.8140M = 4
13C12H
35Cl5
37Cl2O2		HpCDD
3
479.7165M = 4C12H
35Cl7
37Cl2O		NCDPE
5441.7428M = 2C12
35Cl7
37ClO		OCDF
442.9728LockC10F17PFK
443.7399M = 4C12
35Cl6
37Cl2O		OCDF
457.7377M = 2C12
35Cl7
37ClO2		OCDD
459.7348M = 4C12
35Cl6
37Cl2O2		OCDD
469.7779M = 2
13C12
35Cl7
37ClO2		OCDD
3
471.7750M = 4
13C12
35Cl6
37Cl2O2		OCDD
3
513.6775M = 4C12
35Cl8
37Cl2O		DCDPE


1 Nuclidic masses used:

H = 1.007825.

O = 15.994915.

C = 12.00000.


35Cl = 34.968853.


13C = 13.003355.


37Cl = 36.965903.

F = 18.9984.


2 TCDD = Tetrachlorodibenzo-p-dioxin.

PeCDD = Pentachlorodibenzo-p-dioxin.

HxCDD = Hexachlorodibenzo-p-dioxin.

HpCDD = Heptachlorodibenzo-p-dioxin.

OCDD = Octachlorodibenzo-p-dioxin.

HxCDPE = Hexachlorodiphenyl ether.

OCDPE = Octachlorodiphenyl ether.

DCDPE = Decachlorodiphenyl ether.

TCDF = Tetrachlorodibenzofuran.

PeCDF = Pentachlorodibenzofuran.

HxCDF = Hexachlorodibenzofuran.

HpCDF = Heptachlorodibenzofuran.

OCDF = Octachlorodibenzofuran.

HpCDPE = Heptachlorodiphenyl ether.

NCDPE = Nonachlorodiphenyl ether.

PFK = Perfluorokerosene.


3 Labeled compound.


4 There is only one m/z for
37Cl4-2,3,7,8,-TCDD (cleanup standard).


Table 9—Theoretical Ion Abundance Ratios and QC Limits

Number of chlorine atoms
M/Z’s forming ratio
Theoretical ratio
QC limit
1
Lower
Upper
4
2		M/(M = 2)0.770.650.89
5(M = 2)/(M = 4)1.551.321.78
6(M = 2)/(M = 4)1.241.051.43
6
3		M/(M = 2)0.510.430.59
7(M = 2)/(M = 4)1.050.881.20
7
4		M/(M = 2)0.440.370.51
8(M = 2)/(M = 4)0.890.761.02


1 QC limits represent ±15% windows around the theoretical ion abundance ratios.


2 Does not apply to
37Cl4-2,3,7,8-TCDD (cleanup standard).


3 Used for
13C12-HxCDF only.


4 Used for
13C12-HpCDF only.


Table 10—Suggested Sample Quantities To Be Extracted for Various Matrices
1

Sample Matrix
2
Example
Percent solids
Phase
Quantity extracted
Single-phase:
AqueousDrinking water(
3)		1000 mL.
Groundwater
Treated wastewater
SolidDry soil>20Solid10 g.
Compost
Ash
OrganicWaste solventOrganic10 g.
Waste oil
Organic polymer
TissueFishOrganic10 g.
Human adipose
Multi-phase:
Liquid/Solid:
Aqueous/SolidWet soil1-30Solid10 g.
Untreated effluent
Digested municipal sludge
Filter cake
Paper pulp
Organic/solidIndustrial sludge1-100Both10 g.
Oily waste
Liquid/Liquid:
Aqueous/organicIn-process effluentOrganic10 g.
Untreated effluent
Drum waste
Aqueous/organic/solidUntreated effluent>1Organic and solid10 g.
Drum waste


1 The quantity of sample to be extracted is adjusted to provide 10 g of solids (dry weight). One liter of aqueous samples containing 1% solids will contain 10 g of solids. For aqueous samples containing greater than 1% solids, a lesser volume is used so that 10 g of solids (dry weight) will be extracted.


2 The sample matrix may be amorphous for some samples. In general, when the CDDs/CDFs are in contact with a multiphase system in which one of the phases is water, they will be preferentially dispersed in or adsorbed on the alternate phase because of their low solubility in water.


3 Aqueous samples are filtered after spiking with the labeled compounds. The filtrate and the materials trapped on the filter are extracted separately, and the extracts are combined for cleanup and analysis.









24.0 Glossary of Definitions and Purposes

These definitions and purposes are specific to this method but have been conformed to common usage as much as possible.


24.1 Units of weight and Measure and Their Abbreviations.


24.1.1 Symbols:


°C—degrees Celsius

µL—microliter

µm—micrometer


>—greater than

%—percent

24.1.2 Alphabetical abbreviations:

amp—ampere

cm—centimeter

g—gram

h—hour

D—inside diameter

in.—inch

L—liter

M—Molecular ion

m—meter

mg—milligram

min—minute

mL—milliliter

mm—millimeter

m/z—mass-to-charge ratio

N—normal; gram molecular weight of solute divided by hydrogen equivalent of solute, per liter of solution

OD—outside diameter

pg—picogram

ppb—part-per-billion

ppm—part-per-million

ppq—part-per-quadrillion

ppt—part-per-trillion

psig—pounds-per-square inch gauge

v/v—volume per unit volume

w/v—weight per unit volume

24.2 Definitions and Acronyms (in Alphabetical Order).


Analyte—A CDD or CDF tested for by this method. The analytes are listed in Table 1.


Calibration Standard (CAL)—A solution prepared from a secondary standard and/or stock solutions and used to calibrate the response of the instrument with respect to analyte concentration.


Calibration Verification Standard (VER)—The mid-point calibration standard (CS3) that is used in to verify calibration. See Table 4.


CDD—Chlorinated Dibenzo-p-ioxin—The isomers and congeners of tetra-through octa-chlorodibenzo-p-dioxin.


CDF—Chlorinated Dibenzofuran—The isomers and congeners of tetra-through octa-chlorodibenzofuran.


CS1, CS2, CS3, CS4, CS5—See Calibration standards and Table 4.


Field Blank—An aliquot of reagent water or other reference matrix that is placed in a sample container in the laboratory or the field, and treated as a sample in all respects, including exposure to sampling site conditions, storage, preservation, and all analytical procedures. The purpose of the field blank is to determine if the field or sample transporting procedures and environments have contaminated the sample.


GC—Gas chromatograph or gas chromatography.


GPC—Gel permeation chromatograph or gel permeation chromatography.


HPLC—High performance liquid chromatograph or high performance liquid chromatography.


HRGC—High resolution GC.


HRMS—High resolution MS.


IPR—Initial precision and recovery; four aliquots of the diluted PAR standard analyzed to establish the ability to generate acceptable precision and accuracy. An IPR is performed prior to the first time this method is used and any time the method or instrumentation is modified.


K-D—Kuderna-Danish concentrator; a device used to concentrate the analytes in a solvent.


Laboratory Blank—See method blank.


Laboratory Control sample (LCS)—See ongoing precision and recovery standard (OPR).


Laboratory Reagent Blank—See method blank.


May—This action, activity, or procedural step is neither required nor prohibited.


May Not—This action, activity, or procedural step is prohibited.


Method Blank—An aliquot of reagent water that is treated exactly as a sample including exposure to all glassware, equipment, solvents, reagents, internal standards, and surrogates that are used with samples. The method blank is used to determine if analytes or interferences are present in the laboratory environment, the reagents, or the apparatus.


Minimum Level (ML)—The level at which the entire analytical system must give a recognizable signal and acceptable calibration point for the analyte. It is equivalent to the concentration of the lowest calibration standard, assuming that all method-specified sample weights, volumes, and cleanup procedures have been employed.


MS—Mass spectrometer or mass spectrometry.


Must—This action, activity, or procedural step is required.


OPR—Ongoing precision and recovery standard (OPR); a laboratory blank spiked with known quantities of analytes. The OPR is analyzed exactly like a sample. Its purpose is to assure that the results produced by the laboratory remain within the limits specified in this method for precision and recovery.


PAR—Precision and recovery standard; secondary standard that is diluted and spiked to form the IPR and OPR.


PFK—Perfluorokerosene; the mixture of compounds used to calibrate the exact m/z scale in the HRMS.


Preparation Blank—See method blank.


Primary Dilution Standard—A solution containing the specified analytes that is purchased or prepared from stock solutions and diluted as needed to prepare calibration solutions and other solutions.


Quality Control Check Sample (QCS)—A sample containing all or a subset of the analytes at known concentrations. The QCS is obtained from a source external to the laboratory or is prepared from a source of standards different from the source of calibration standards. It is used to check laboratory performance with test materials prepared external to the normal preparation process.


Reagent Water—Water demonstrated to be free from the analytes of interest and potentially interfering substances at the method detection limit for the analyte.


Relative Standard Deviation (RSD)—The standard deviation times 100 divided by the mean. Also termed “coefficient of variation.”


RF—Response factor. See Section 10.6.1.


RR—Relative response. See Section 10.5.2.


RSD—See relative standard deviation.


SDS—Soxhlet/Dean-Stark extractor; an extraction device applied to the extraction of solid and semi-solid materials (Reference 7).


Should—This action, activity, or procedural step is suggested but not required.


SICP—Selected ion current profile; the line described by the signal at an exact m/z.


SPE—Solid-phase extraction; an extraction technique in which an analyte is extracted from an aqueous sample by passage over or through a material capable of reversibly adsorbing the analyte. Also termed liquid-solid extraction.


Stock Solution—A solution containing an analyte that is prepared using a reference material traceable to EPA, the National Institute of Science and Technology (NIST), or a source that will attest to the purity and authenticity of the reference material.


TCDD—Tetrachlorodibenzo-p-dioxin.


TCDF—Tetrachlorodibenzofuran.


VER—See calibration verification standard.


Method 1624 Revision B—Volatile Organic Compounds by Isotope Dilution GC/MS

1. Scope and Application

1.1 This method is designed to determine the volatile toxic organic pollutants associated with the 1976 Consent Decree and additional compounds amenable to purge and trap gas chromatography-mass spectrometry (GC/MS).


1.2 The chemical compounds listed in table 1 may be determined in municipal and industrial discharges by this method. The methmd is designed to meet the survey requirements of Effluent Guidelines Division (EGD) and the National Pollutants Discharge Elimination System (NPDES) under 40 CFR 136.1 and 136.5. Any modifications of this method, beyond those expressly permitted, shall be considered as major modifications subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.3 The detection limit of this method is usually dependent on the level of interferences rather than instrumental limitations. The limits in table 2 represent the minimum quantity that can be detected with no interferences present.


1.4 The GC/MS portions of this method are for use only by analysts experienced with GC/MS or under the close supervision of such qualified persons. Laboratories unfamiliar with the analyses of environmental samples by GC/MS should run the performance tests in reference 1 before beginning.


2. Summary of Method

2.1 Stable isotopically labeled analogs of the compounds of interest are added to a 5 mL water sample. The sample is purged at 20-25 °C with an inert gas in a specially designed chamber. The volatile organic compounds are transferred from the aqueous phase into the gaseous phase where they are passed into a sorbent column and trapped. After purging is completed, the trap is backflushed and heated rapidly to desorb the compounds into a gas chromatograph (GC). The compounds are separated by the GC and detected by a mass spectrometer (MS) (references 2 and 3). The labeled compounds serve to correct the variability of the analytical technique.


2.2 Identification of a compound (qualitative analysis) is performed by comparing the GC retention time and the background corrected characteristic spectral masses with those of authentic standards.


2.3 Quantitative analysis is performed by GC/MS using extracted ion current profile (EICP) areas. Isotope dilution is used when labeled compounds are available; otherwise, an internal standard method is used.


2.4 Quality is assured through reproducible calibration and testing of the purge and trap and GC/MS systems.


3. Contamination and Interferences

3.1 Impurities in the purge gas, organic compounds out-gassing from the plumbing upstream of the trap, and solvent vapors in the laboratory account for the majority of contamination problems. The analytical system is demonstrated to be free from interferences under conditions of the analysis by analyzing blanks initially and with each sample lot (samples analyzed on the same 8 hr shift), as described in Section 8.5.


3.2 Samples can be contaminated by diffusion of volatile organic compounds (particularly methylene chloride) through the bottle seal during shipment and storage. A field blank prepared from reagent water and carried through the sampling and handling protocol serves as a check on such contamination.


3.3 Contamination by carry-over can occur when high level and low level samples are analyzed sequentially. To reduce carry-over, the purging device and sample syringe are rinsed between samples with reagent water. When an unusually concentrated sample is encountered, it is followed by analysis of a reagent water blank to check for carry-over. For samples containing large amounts of water soluble materials, suspended solids, high boiling compounds, or high levels or purgeable compounds, the purge device is washed with soap solution, rinsed with tap and distilled water, and dried in an oven at 100-125 °C. The trap and other parts of the system are also subject to contamination; therefore, frequent bakeout and purging of the entire system may be required.


3.4 Interferences resulting from samples will vary considerably from source to source, depending on the diversity of the industrial complex or municipality being sampled.


4. Safety

4.1 The toxicity or carcinogenicity of each compound or reagent used in this method has not been precisely determined; however, each chemical compound should be treated as a potential health hazard. Exposure to these compounds should be reduced to the lowest possible level. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of data handling sheets should also be made available to all personnel involved in these analyses. Additional information on laboratory safety can be found in references 4-6.


4.2 The following compounds covered by this method have been tentatively classified as known or suspected human or mammalian carcinogens: benzene, carbon tetrachloride, chloroform, and vinyl chloride. Primary standards of these toxic compounds should be prepared in a hood, and a NIOSH/MESA approved toxic gas respirator should be worn when high concentrations are handled.


5. Apparatus and Materials

5.1 Sample bottles for discrete sampling.


5.1.1 Bottle—25 to 40 mL with screw cap (Pierce 13075, or equivalent). Detergent wash, rinse with tap and distilled water, and dry at >105 °C for one hr minimum before use.


5.1.2 Septum—Teflon-faced silicone (Pierce 12722, or equivalent), cleaned as above and baked at 100-200 °C, for one hour minimum.


5.2 Purge and trap device—consists of purging device, trap, and desorber. Complete devices are commercially available.


5.2.1 Purging device—designed to accept 5 mL samples with water column at least 3 cm deep. The volume of the gaseous head space between the water and trap shall be less than 15 mL. The purge gas shall be introduced less than 5 mm from the base of the water column and shall pass through the water as bubbles with a diameter less than 3 mm. The purging device shown in Figure 1 meets these criteria.


5.2.2 Trap—25 to 30 cm × 2.5 mm i.d. minimum, containing the following:


5.2.2.1 Methyl silicone packing—one ±0.2 cm, 3 percent OV-1 on 60/80 mesh Chromosorb W, or equivalent.


5.2.2.2 Porous polymer—15 ±1.0 cm, Tenax GC (2,6-diphenylene oxide polymer), 60/80 mesh, chromatographic grade, or equivalent.


5.2.2.3 Silica gel—8 ±1.0 cm, Davison Chemical, 35/60 mesh, grade 15, or equivalent. The trap shown in Figure 2 meets these specifications.


5.2.3 Desorber—shall heat the trap to 175 ±5 °C in 45 seconds or less. The polymer section of the trap shall not exceed 180 °C, and the remaining sections shall not exceed 220 °C. The desorber shown in Figure 2 meets these specifications.


5.2.4 The purge and trap device may be a separate unit or coupled to a GC as shown in Figures 3 and 4.


5.3 Gas chromatograph—shall be linearly temperature programmable with initial and final holds, shall contain a glass jet separator as the MS interface, and shall produce results which meet the calibration (Section 7), quality assurance (Section 8), and performance tests (Section 11) of this method.


5.3.1 Column—2.8 ±0.4 m × 2 ±0.5 mm i. d. glass, packekd with one percent SP-1000 on Carbopak B, 60/80 mesh, or equivalent.


5.4 Mass spectrometer—70 eV electron impact ionization; shall repetitively scan from 20 to 250 amu every 2-3 seconds, and produce a unit resolution (valleys between m/z 174-176 less than 10 percent of the height of the m/z 175 peak), background corrected mass spectrum from 50 ng 4-bromo-fluorobenzene (BFB) injected into the GC. The BFB spectrum shall meet the mass-intensity criteria in Table 3. All portions of the GC column, transfer lines, and separator which connect the GC column to the ion source shall remain at or above the column temperature during analysis to preclude condensation of less volatile compounds.


5.5 Data system—shall collect and record MS data, store mass intensity data in spectral libraries, process GC/MS data and generate reports, and shall calculate and record response factors.


5.5.1 Data acquisition—mass spectra shall be collected continuously throughout the analysis and stored on a mass storage device.


5.5.2 Mass spectral libraries—user created libraries containing mass spectra obtained from analysis of authentic standards shall be employed to reverse search GC/MS runs for the compounds of interest (Section 7.2).


5.5.3 Data processing—the data system shall be used to search, locate, identify, and quantify the compounds of interest in each GC/MS analysis. Software routines shall be employed to compute retention times and EICP areas. Displays of spectra, mass chromatograms, and library comparisons are required to verify results.


5.5.4 Response factors and multipoint calibrations—the data system shall be used to record and maintain lists of response factors (response ratios for isotope dilution) and generate multi-point calibration curves (Section 7). Computations of relative standard deviation (coefficient of variation) are useful for testing calibration linearity. Statistics on initial and on-going performance shall be maintained (Sections 8 and 11).


5.6 Syringes—5 mL glass hypodermic, with Luer-lok tips.


5.7 Micro syringes—10, 25, and 100 uL.


5.8 Syringe valves—2-way, with Luer ends (Telfon or Kel-F).


5.9 Syringe—5 mL, gas-tight, with shut-off valve.


5.10 Bottles—15 mL., screw-cap with Telfon liner.


5.11 Balance—analytical, capable of weighing 0.1 mg.


6. Reagents and Standards

6.1 Reagent water—water in which the compounds of interest and interfering compounds are not detected by this method (Section 11.7). It may be generated by any of the following methods:


6.1.1 Activated carbon—pass tap water through a carbon bed (Calgon Filtrasorb-300, or equivalent).


6.1.2 Water purifier—pass tap water through a purifier (Millipore Super Q, or equivalent).


6.1.3 Boil and purge—heat tap water to 90-100 °C and bubble contaminant free inert gas through it for approx one hour. While still hot, transfer the water to screw-cap bottles and seal with a Teflon-lined cap.


6.2 Sodium thiosulfate—ACS granular.


6.3 Methanol—pesticide quality or equivalent.


6.4 Standard solutions—purchased as solution or mixtures with certification to their purity, concentration, and authenticity, or prepared from materials of known purity and composition. If compound purity is 96 percent or greater, the weight may be used without correction to calculate the concentration of the standard.


6.5 Preparation of stock solutions—prepare in methanol using liquid or gaseous standards per the steps below. Observe the safety precautions given in Section 4.


6.5.1 Place approx 9.8 mL of methanol in a 10 mL ground glass stoppered volumetric flask. Allow the flask to stand unstoppered for approximately 10 minutes or until all methanol wetted surfaces have dried. In each case, weigh the flask, immediately add the compound, then immediately reweigh to prevent evaporation losses from affecting the measurement.


6.5.1.1 Liquids—using a 100 µL syringe, permit 2 drops of liquid to fall into the methanol without contacting the leck of the flask. Alternatively, inject a known volume of the compound into the methanol in the flask using a micro-syringe.


6.5.1.2 Gases (chloromethane, bromomethane, chloroethane, vinyl chloride)—fill a valved 5 mL gas-tight syringe with the compound. Lower the needle to approximately 5 mm above the methanol meniscus. Slowly introduce the compound above the surface of the meniscus. The gas will dissolve rapidly in the methanol.


6.5.2 Fill the flask to volume, stopper, then mix by inverting several times. Calculate the concentration in mg/mL (µg/µL) from the weight gain (or density if a known volume was injected).


6.5.3 Transfer the stock solution to a Teflon sealed screw-cap-bottle. Store, with minimal headspace, in the dark at −10 to −20 °C.


6.5.4 Prepare fresh standards weekly for the gases and 2-chloroethylvinyl ether. All other standards are replaced after one month, or sooner if comparison with check standards indicate a change in concentration. Quality control check standards that can be used to determine the accuracy of calibration standards are available from the US Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio.


6.6 Labeled compound spiking solution—from stock standard solutions prepared as above, or from mixtures, prepare the spiking solution to contain a concentration such that a 5-10 µL spike into each 5 mL sample, blank, or aqueous standard analyzed will result in a concentration of 20 µg/L of each labeled compound. For the gases and for the water soluble compounds (acrolein, acrylonitrile, acetone, diethyl ether, and MEK), a concentration of 100 µg/L may be used. Include the internal standards (Section 7.5) in this solution so that a concentration of 20 µg/L in each sample, blank, or aqueous standard will be produced.


6.7 Secondary standards—using stock solutions, prepare a secondary standard in methanol to contain each pollutant at a concentration of 500 µg/mL For the gases and water soluble compounds (Section 6.6), a concentration of 2.5 mg/mL may be used.


6.7.1 Aqueous calibration standards—using a 25 µL syringe, add 20 µL of the secondary standard (Section 6.7) to 50, 100, 200, 500, and 1000 mL of reagent water to produce concentrations of 200, 100, 50, 20, and 10 µg/L, respectively. If the higher concentration standard for the gases and water soluble compounds was chosen (Section 6.6), these compounds will be at concentrations of 1000, 500, 250, 100, and 50 µg/L in the aqueous calibration standards.


6.7.2 Aqueous performance standard—an aqueous standard containing all pollutants, internal standards, labeled compounds, and BFB is prepared daily, and analyzed each shift to demonstrate performance (Section 11). This standard shall contain either 20 or 100 µg/L of the labeled and pollutant gases and water soluble compounds, 10 µg/L BFB, and 20 µg/L of all other pollutants, labeled compounds, and internal standards. It may be the nominal 20 µg/L aqueous calibration standard (Section 6.7.1).


6.7.3 A methanolic standard containing all pollutants and internal standards is prepared to demonstrate recovery of these compounds when syringe injection and purge and trap analyses are compared. This standard shall contain either 100 µg/mL or 500 µg/mL of the gases and water soluble compounds, and 100 µg/mL of the remaining pollutants and internal standards (consistent with the amounts in the aqueous performance standard in 6.7.2).


6.7.4 Other standards which may be needed are those for test of BFB performance (Section 7.1) and for collection of mass spectra for storage in spectral libraries (Section 7.2).


7. Calibration

7.1 Assemble the gas chromatographic apparatus and establish operating conditions given in table 2. By injecting standards into the GC, demonstrate that the analytical system meets the detection limits in table 2 and the mass-intensity criteria in table 3 for 50 ng BFB.


7.2 Mass spectral libraries—detection and identification of the compound of interest are dependent upon the spectra stored in user created libraries.


7.2.1 Obtain a mass spectrum of each pollutant and labeled compound and each internal standard by analyzing an authentic standard either singly or as part of a mixture in which there is no interference between closely eluted components. That only a single compound is present is determined by examination of the spectrum. Fragments not attributable to the compound under study indicate the presence of an interfering compound. Adjust the analytical conditions and scan rate (for this test only) to produce an undistorted spectrum at the GC peak maximum. An undistorted spectrum will usually be obtained if five complete spectra are collected across the upper half of the GC peak. Software algorithms designed to “enhance” the spectrum may eliminate distortion, but may also eliminate authentic m/z’s or introduce other distortion.


7.2.3 The authentic reference spectrum is obtained under BFB tuning conditions (Section 7.1 and table 3) to normalize it to spectra from other instruments.


7.2.4 The spectrum is edited by saving the 5 most intense mass spectral peaks and all other mass spectral peaks greater than 10 percent of the base peak. This spectrum is stored for reverse search and for compound confirmation.


7.3 Assemble the purge and trap device. Pack the trap as shown in Figure 2 and condition overnight at 170-180 °C by backflushing with an inert gas at a flow rate of 20-30 mL/min. Condition traps daily for a minimum of 10 minutes prior to use.


7.3.1 Analyze the aqueous performance standard (Section 6.7.2) according to the purge and trap procedure in Section 10. Compute the area at the primary m/z (table 4) for each compound. Compare these areas to those obtained by injecting one µL of the methanolic standard (Section 6.7.3) to determine compound recovery. The recovery shall be greater than 20 percent for the water soluble compounds, and 60-110 percent for all other compounds. This recovery is demonstrated initially for each purge and trap GC/MS system. The test is repeated only if the purge and trap or GC/MS systems are modified in any way that might result in a change in recovery.


7.3.2 Demonstrate that 100 ng toluene (or toluene-d8) produces an area at m/z 91 (or 99) approx one-tenth that required to exceed the linear range of the system. The exact value must be determined by experience for each instrument. It is used to match the calibration range of the instrument to the analytical range and detection limits required.


7.4 Calibration by isotope dilution—the isotope dilution approach is used for the purgeable organic compounds when appropriate labeled compounds are available and when interferences do not preclude the analysis. If labeled compounds are not available, or interferences are present, internal standard methods (Section 7.5 or 7.6) are used. A calibration curve encompassing the concentration range of interest is prepared for each compound determined. The relative response (RR) vs concentration (µg/L) is plotted or computed using a linear regression. An example of a calibration curve for toluene using toluene-d8 is given in figure 5. Also shown are the ±10 percent error limits (dotted lines). Relative response is determined according to the procedures described below. A minimum of five data points are required for calibration (Section 7.4.4).


7.4.1 The relative response (RR) of pollutant to labeled compound is determined from isotope ratio values calculated from acquired data. Three isotope ratios are used in this process:


RX = the isotope ratio measured in the pure pollutant (figure 6A).

Ry = the isotope ratio of pure labeled compound (figure 6B).

Rm = the isotope ratio measured in the analytical mixture of the pollutant and labeled compounds (figure 6C).

The correct way to calculate RR is: RR = (Ry−Rm) (RX + 1)/(Rm−RX)(Ry + 1) If Rm is not between 2Ry and 0.5RX, the method does not apply and the sample is analyzed by internal or external standard methods (Section 7.5 or 7.6).


7.4.2 In most cases, the retention times of the pollutant and labeled compound are the same and isotope ratios (R’s) can be calculated from the EICP areas, where: R = (area at m1/z)/(area at m2/z) If either of the areas is zero, it is assigned a value of one in the calculations; that is, if: area of m1/z = 50721, and area of m2/z = 0, then R = 50721/1 = 50720. The m/z’s are always selected such that RX>Ry. When there is a difference in retention times (RT) between the pollutant and labeled compounds, special precautions are required to determine the isotope ratios.


RX, Ry, and Rm are defined as follows:


RX=[area m1/z (at RT1)]/1

Ry = 1/[area m2/z (at RT2)]

Rm=[area m1/z (at RT1)]/[area m2/z (at RT2)]

7.4.3 An example of the above calculations can be taken from the data plotted in figure 6 for toluene and toluene-d8. For these data, RX = 168920/1 = 168900, Ry = 1/60960 = 0.00001640, and Rm = 96868/82508 = 1.174. The RR for the above data is then calculated using the equation given in Section 7.4.1. For the example, RR = 1.174.



Note:

Not all labeled compounds elute before their pollutant analogs.


7.4.4 To calibrate the analytical system by isotope dilution, analyze a 5 mL aliquot of each of the aqueous calibration standards (Section 6.7.1) spiked with an appropriate constant amount of the labeled compound spiking solution (Section 6.6), using the purge and trap procedure in section 10. Compute the RR at each concentration.


7.4.5 Linearity—if the ratio of relative response to concentration for any compound is constant (less than 20 percent coefficient of variation) over the 5 point calibration range, an averaged relative response/concentration ratio may be used for that compound; otherwise, the complete calibration curve for that compound shall be used over the 5 point calibration range.


7.5 Calibration by internal standard—used when criteria for isotope dilution (Section 7.4) cannot be met. The method is applied to pollutants having no labeled analog and to the labeled compounds. The internal standards used for volatiles analyses are bromochloromethane, 2-bromo-1-chloropropane, and 1,4-dichlorobutane. Concentrations of the labeled compounds and pollutants without labeled analogs are computed relative to the nearest eluted internal standard, as shown in table 2.


7.5.1 Response factors—calibration requires the determination of response factors (RF) which are defined by the following equation:


RF = (AsxCis)/(AisxCs), where As is the EICP area at the characteristic m/z for the compound in the daily standard. Ais is the EICP area at the characteristic m/z for the internal standard.


Cis is the concentration (ug/L) of the internal standard


Cs is the concentration of the pollutant in the daily standard.


7.5.2 The response factor is determined at 10, 20, 50, 100, and 200 ug/L for the pollutants (optionally at five times these concentrations for gases and water soluble pollutants—see Section 6.7), in a way analogous to that for calibration by isotope dilution (Section 7.4.4). The RF is plotted against concentration for each compound in the standard (Cs) to produce a calibration curve.


7.5.3 Linearity—if the response factor (RF) for any compound is constant (less than 35 percent coefficient of variation) over the 5 point calibration range, an averaged response factor may be used for that compound; otherwise, the complete calibration curve for that compound shall be used over the 5 point range.


7.6 Combined calibration—by adding the isotopically labeled compounds and internal standards (Section 6.6) to the aqueous calibration standards (Section 6.7.1), a single set of analyses can be used to produce calibration curves for the isotope dilution and internal standard methods. These curves are verified each shift (Section 11.5) by purging the aqueous performance standard (Section 6.7.2). Recalibration is required only if calibration and on-going performance (Section 11.5) criteria cannot be met.


8. Quality Assurance/Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability, analysis of samples spiked with labeled compounds to evaluate and document data quality, and analysis of standards and blanks as tests of continued performance. Laboratory performance is compared to established performance criteria to determine if the results of analyses meet the performance characteristics of the method.


8.1.1 The analyst shall make an initial demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 The analyst is permitted to modify this method to improve separations or lower the costs of measurements, provided all performance specifications are met. Each time a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2 to demonstrate method performance.


8.1.3 Analyses of blanks are required to demonstrate freedom from contamination and that the compounds of interest and interfering compounds have not been carried over from a previous analysis (Section 3). The procedures and criteria for analysis of a blank are described in Sections 8.5 and 11.7.


8.1.4 The laboratory shall spike all samples with labeled compounds to monitor method performance. This test is described in Section 8.3. When results of these spikes indicate atypical method performance for samples, the samples are diluted to bring method performance within acceptable limits (Section 14.2).


8.1.5 The laboratory shall, on an on-going basis, demonstrate through the analysis of the aqueous performance standard (Section 6.7.2) that the analysis system is in control. This procedure is described in Sections 11.1 and 11.5.


8.1.6 The laboratory shall maintain records to define the quality of data that is generated. Development of accuracy statements is described in Sections 8.4 and 11.5.2.


8.2 Initial precision and accuracy—to establish the ability to generate acceptable precision and accuracy, the analyst shall perform the following operations:


8.2.1 Analyze two sets of four 5-mL aliquots (8 aliquots total) of the aqueous performance standard (Section 6.7.2) according to the method beginning in Section 10.


8.2.2 Using results of the first set of four analyses in Section 8.2.1, compute the average recovery (X
) in µg/L and the standard deviation of the recovery (s) in µg/L for each compound, by isotope dilution for polluitants with a labeled analog, and by internal standard for labeled compounds and pollutants with no labeled analog.


8.2.3 For each compound, compare s and X
with the corresponding limits for initial precision and accuracy found in table 5. If s and X
for all compounds meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may begin. If individual X
falls outside the range for accuracy, system performance is unacceptable for that compound.



Note:

The large number of compounds in table 5 present a substantial probability that one or more will fail one of the acceptance criteria when all compoulds are analyzed. To determine if the analytical system is out of control, or if the failure can be attributed to probability, proceed as follows:


8.2.4 Using the results of the second set of four analyses, compute s and X
for only those compounds which failed the test of the first set of four analyses (Section 8.2.3). If these compounds now pass, system performance is acceptable for all compounds and analysis of blanks and samples may begin. If, however, any of the same compounds fail again, the analysis system is not performing properly for the compound(s) in question. In this event, correct the problem and repeat the entire test (Section 8.2.1).


8.3 The laboratory shall spike all samples with labeled compounds to assess method performance on the sample matrix.


8.3.1 Spike and analyze each sample according to the method beginning in Section 10.


8.3.2 Compute the percent recovery (P) of the labeled compounds using the internal standard method (Section 7.5).


8.3.3 Compare the percent recovery for each compound with the corresponding labeled compound recovery limit in table 5. If the recovery of any compound falls outside its warning limit, method performance is unacceptable for that compound in that sample. Therefore, the sample matrix is complex and the sample is to be diluted and reanalyzed, per Section 14.2.


8.4 As part of the QA program for the laboratory, method accuracy for wastewater samples shall be assessed and records shall be maintained. After the analysis of five wastewater samples for which the labeled compounds pass the tests in Section 8.3.3, compute the average percent recovery (P) and the standard deviation of the percent recovery (sp) for the labeled compounds only. Express the accuracy assessment as a percent recovery interval from P−2sp to P + 2sp. For example, if P = 90% and sp = 10%, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each compound on a regular basis (e.g. after each 5-10 new accuracy measurements).


8.5 Blanks—reagent water blanks are analyzed to demonstrate freedom from carry-over (Section 3) and contamination.


8.5.1 The level at which the purge and trap system will carry greater than 5 µg/L of a pollutant of interest (table 1) into a succeeding blank shall be determined by analyzing successively larger concentrations of these compounds. When a sample contains this concentration or more, a blank shall be analyzed immediately following this sample to demonstrate no carry-over at the 5 µg/L level.


8.5.2 With each sample lot (samples analyzed on the same 8 hr shift), a blank shall be analyzed immediately after analysis of the aqueous performance standard (Section 11.1) to demonstrate freedom from contamination. If any of the compounds of interest (table 1) or any potentially interfering compound is found in a blank at greater than 10 µg/L (assuming a response factor of 1 relative to the nearest eluted internal standard for compounds not listed in table 1), analysis of samples is halted until the source of contamination is eliminated and a blank shows no evidence of contamination at this level.


8.6 The specifications contained in this method can be met if the apparatus used is calibrated properly, then maintained in a calibrated state.


The standards used for calibration (Section 7), calibration verification (Section 11.5) and for initial (Section 8.2) and on-going (Section 11.5) precision and accuracy should be identical, so that the most precise results will be obtained. The GC/MS instrument in particular will provide the most reproducible results if dedicated to the settings and conditions required for the analyses of volatiles by this method.


8.7 Depending on specific program requirements, field replicates may be collected to determine the precision of the sampling technique, and spiked samples may be required to determine the accuracy of the analysis when internal or external standard methods are used.


9. Sample Collection, Preservation, and Handling

9.1 Grab samples are collected in glass containers having a total volume greater than 20 mL. Fill sample bottles so that no air bubbles pass through the sample as the bottle is filled. Seal each bottle so that no air bubbles are entrapped. Maintain the hermetic seal on the sample bottle until time of analysis.


9.2 Samples are maintained at 0-4 °C from the time of collection until analysis. If the sample contains residual chlorine, add sodium thiosulfate preservative (10 mg/40 mL) to the empty sample bottles just prior to shipment to the sample site. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine (Reference 8). If preservative has been added, shake bottle vigorously for one minute immediately after filling.


9.3 Experimental evidence indicates that some aromatic compounds, notably benzene, toluene, and ethyl benzene are susceptible to rapid biological degradation under certain environmental conditions. Refrigeration alone may not be adequate to preserve these compounds in wastewaters for more than seven days. For this reason, a separate sample should be collected, acidified, and analyzed when these aromatics are to be determined. Collect about 500 mL of sample in a clean container.


Adjust the pH of the sample to about 2 by adding HCl (1 + 1) while stirring. Check pH with narrow range (1.4 to 2.8) pH paper. Fill a sample container as described in Section 9.1. If residual chlorine is present, add sodium thiosulfate to a separate sample container and fill as in Section 9.1.


9.4 All samples shall be analyzed within 14 days of collection.


10. Purge, Trap, and GC/MS Analysis

10.1 Remove standards and samples from cold storage and bring to 20-25 °.


10.2 Adjust the purge gas flow rate to 40 ±4 mL/min. Attach the trap inlet to the purging device and set the valve to the purge mode (figure 3). Open the syringe valve located on the purging device sample introduction needle (figure 1).


10.3 Remove the plunger from a 5-mL syringe and attach a closed syringe valve. Open the sample bottle and carefully pour the sample into the syringe barrel until it overflows. Replace the plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume to 5.0 mL. Because this process of taking an aliquot destroys the validity of the sample for future analysis, fill a second syringe at this time to protect against possible loss of data. Add an appropriate amount of the labeled compound spiking solution (Section 6.6) through the valve bore, then close the valve.


10.4 Attach the syringe valve assembly to the syringe valve on the purging device. Open both syringe valves and inject the sample into the purging chamber.


10.5 Close both valves and purge the sample for 11.0 ±0.1 minutes at 20-25 °C.


10.6 After the 11 minute purge time, attach the trap to the chromatograph and set the purge and trap apparatus to the desorb mode (figure 4). Desorb the trapped compounds into the GC column by heating the trap to 170-180 °C while backflushing with carrier gas at 20-60 mL/min for four minutes. Start MS data acquisition upon start of the desorb cycle, and start the GC column temperature program 3 minutes later. Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and detection limits that were achieved under these conditions. Other columns may be used provided the requirements in Section 8 can be met. If the priority pollutant gases produce GC peaks so broad that the precision and recovery specifications (Section 8.2) cannot be met, the column may be cooled to ambient or sub-ambient temperatures to sharpen these peaks.


10.7 While analysis of the desorbed compounds proceeds, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL portions of reagent water. After the purging device has been emptied, allow the purge gas to vent through the chamber until the frit is dry, so that it is ready for the next sample.


10.8 After desorbing the sample for four minutes, recondition the trap by returning to the purge mode. Wait 15 seconds, then close the syringe valve on the purging device to begin gas flow through the trap. Maintain the trap temperature at 170-180 °C. After approximately seven minutes, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When cool, the trap is ready for the next sample.


11. System Performance

11.1 At the beginning of each 8 hr shift during which analyses are performed, system calibration and performance shall be verified for all pollutants and labeled compounds. For these tests, analysis of the aqueous performance standard (Section 6.7.2) shall be used to verify all performance criteria. Adjustment and/or recalibration (per Section 7) shall be performed until all performance criteria are met. Only after all performance criteria are met may blanks and samples be analyzed.


11.2 BFB spectrum validity—the criteria in table 3 shall be met.


11.3 Retention times—the absolute retention times of all compounds shall approximate those given in Table 2.


11.4 GC resolution—the valley height between toluene and toluene-d8 (at m/z 91 and 99 plotted on the same graph) shall be less than 10 percent of the taller of the two peaks.


11.5 Calibration verification and on-going precision and accuracy—compute the concentration of each polutant (Table 1) by isotope dilution (Section 7.4) for those compmunds which have labeled analogs. Compute the concentration of each pollutant (Table 1) which has no labeled analog by the internal standard method (Section 7.5). Compute the concentration of the labeled compounds by the internal standard method. These concentrations are computed based on the calibration data determined in Section 7.


11.5.1 For each pollutant and labeled compound, compare the concentration with the corresponding limit for on-going accuracy in Table 5. If all compmunds meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may continue. If any individual value falls outside the range given, system performance is unacceptable for that compound.



Note:

The large number of compounds in Table 5 present a substantial probability that one or more will fail the acceptance criteria when all compounds are analyzed. To determine if the analytical system is out of control, or if the failure may be attributed to probability, proceed as follows:


11.5.1.1 Analyze a second aliquot of the aqueous performance standard (Section 6.7.2).


11.5.1.2 Compute the concentration for only those compounds which failed the first test (Section 11.5.1). If these compounds now pass, system performance is acceptable for all compounds and analyses of blanks and samples may proceed. If, however, any of the compounds fail again, the measurement system is not performing properly for these compounds. In this event, locate and correct the problem or recalibrate the system (Section 7), and repeat the entire test (Section 11.1) for all compounds.


11.5.2 Add results which pass the specification in 11.5.1.2 to initial (Section 8.2) and previous on-going data. Update QC charts to form a graphic representation of laboratory performance (Figure 7). Develop a statement of accuracy for each pollutant and labeled compound by calculating the average percentage recovery (R) and the standard deviation of percent recovery (sr). Express the accuracy as a recovery interval from R−2sr to R + 2sr. For example, if R = 95% and sr = 5%, the accuracy is 85-105 percent.


12. Qualitative Determination—Accomplished by Comparison of Data from Analysis of a Sample or Blank with Data from Analysis of the Shift Standard (Section 11.1). Identification is Confirmed When Spectra and Retention Times Agree Per the Criteria Below

12.1 Labeled compounds and pollutants having no labeled analog:


12.1.1 The signals for all characteristic masses stored in the spectral library (Section 7.2.4) shall be present and shall maximize within the same two consecutive scans.


12.1.2 Either (1) the background corrected EICP areas, or (2) the corrected relative intensities of the mass spectral peaks at the GC peak maximum shall agree within a factor of two (0.5 to 2 times) for all masses stored in the library.


12.1.3 The retention time relative to the nearest eluted internal standard shall be within ±7 scans or ±20 seconds, whichever is greater.


12.2 Pollutants having a labeled analog:


12.2.1 The signals for all characteristic masses stored in the spectral library (Section 7.2.4) shall be present and shall maximize within the same two consecutive scans.


12.2.2 Either (1) the background corrected EICP areas, or (2) the corrected relative intensities of the mass spectral peaks at the GC peak maximum shall agree within a factor of two for all masses stored in the spectral library.


12.2.3 The retention time difference between the pollutant and its labeled analog shall agree within ±2 scans or ±6 seconds (whichever is greater) of this difference in the shift standard (Section 11.1).


12.3 Masses present in the experimental mass spectrum that are not present in the reference mass spectrum shall be accounted for by contaminant or background ions. If the experimental mass spectrum is contaminated, an experienced spectrometrist (Section 1.4) is to determine the presence or absence of the compound.


13. Quantitative Determination

13.1 Isotope dilution—by adding a known amount of a labeled compound to every sample prior to purging, correction for recovery of the pollutant can be made because the pollutant and its labeled analog exhibit the same effects upon purging, desorption, and gas chromatography. Relative response (RR) values for sample mixtures are used in conjunction with calibration curves described in Section 7.4 to determine concentrations directly, so long as labeled compound spiking levels are constant. For the toluene example given in Figure 6 (Section 7.4.3), RR would be equal to 1.174. For this RR value, the toluene calibration curve given in Figure 5 indicates a concentration of 31.8 µg/L.


13.2 Internal standard—calculate the concentration using the response factor determined from calibration data (Section 7.5) and the following equation:


Concentration = (As × Cis)/(Ais × RF) where the terms are as defined in Section 7.5.1.


13.3 If the EICP area at the quantitation mass for any compound exceeds the calibration range of the system, the sample is diluted by successive factors of 10 and these dilutions are analyzed until the area is within the calibration range.


13.4 Report results for all pollutants and labeled compounds (Table 1) found in all standards, blanks, and samples, in µg/L to three significant figures. Results for samples which have been diluted are reported at the least dilute level at which the area at the quantitation mass is within the calibration range (Section 13.3) and the labeled compound recovery is within the normal range for the Method (Section 14.2).


14. Analysis of Complex Samples

14.1 Untreated effluents and other samples frequently contain high levels (>1000 µg/L) of the compounds of interest and of interfering compounds. Some samples will foam excessively when purged; others will overload the trap/or GC column.


14.2 Dilute 0.5 mL of sample with 4.5 mL of reagent water and analyze this diluted sample when labeled compound recovery is outside the range given in Table 5. If the recovery remains outside of the range for this diluted sample, the aqueous performance standard shall be analyzed (Section 11) and calibration verified (Section 11.5). If the recovery for the labeled compmund in the aqueous performance standard is outside the range given in Table 5, the analytical system is out of control. In this case, the instrumelt shall be repaired, the performance specifications in Section 11 shall be met, and the analysis of the undiluted sample shall be repeated. If the recovery for the aqueous performance standard is within the range given in Table 5, the method does not work on the sample being analyzed and the result may not be reported for regulatory compliance purposes.


14.3 Reverse search computer programs can misinterpret the spectrum of chromatographically unresolved pollutant and labeled compound pairs with overlapping spectra when a high level of the pollutant is present. Examine each chromatogram for peaks greater than the height of the internal standard peaks. These peaks can obscure the compounds of interest.


15. Method Performance

15.1 The specifications for this method were taken from the inter-laboratory validation of EPA Method 624 (reference 9). Method 1624 has been shown to yield slightly better performance on treated effluents than Method 624. Additional method performance data can be found in Reference 10.


References

1. “Performance Tests for the Evaluation of Computerized Gas Chromatography/Mass Spectrometry Equipment and Laboratories,” USEPA, EMSL/Cincinnati, OH 45268, EPA-600/4-80-025 (April 1980).


2. Bellar, T.A. and Lichtenberg, J.J., “Journal American Water Works Association,” 66, 739 (1974).


3. Bellar, T.A. and Lichtenberg, J.J., “Semi-automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds,” in Measurement of Organic Pollutants Water and Wastewater, C.E. VanHall, ed., American Society for Testing Materials, Philadelphia, PA, Special Technical Publication 686, (1978).


4. “Working with Carcinogens,” DHEW, PHS, NIOSH, Publication 77-206 (1977).


5. “OSHA Safety and Health Standards, General Industry,” 29 CFR part 1910, OSHA 2206, (1976).


6. “Safety in Academic Chemistry Laboratories,” American Chemical Society Publication, Committee on Chemical Safety (1979).


7. “Handbook of Analytical Quality Control in Water and Wastewater Laboratories,” USEPA, EMSL/Cincinnati, OH 45268, EPA-4-79-019 (March 1979).


8. “Methods 330.4 and 330.5 for Total Residual Chlorine,” USEPA, EMSL/Cincinnati, OH 45268, EPA-4-79-020 (March 1979).


9. “EPA Method Study 29 EPA Method 624—Purgeables,” EPA 600/4-84-054, National Technical Information Service, PB84-209915, Springfield, Virginia 22161, June 1984.


10. “Colby, B.N., Beimer, R.G., Rushneck, D.R., and Telliard, W.A., “Isotope Dilution Gas Chromatography-Mass Spectrometry for the Determination of Priority Pollutants in Industrial Effluents,” USEPA, Effluent Guidelines Division, Washington, DC 20460 (1980).


Table 1—Volatile Organic Compounds Analyzed by Isotope Dilution Gc/MS

Compound
Storet
CAS registry
EPA-EGD
NPDES
Acetone8155267-64-1516 V
Acrolein34210107-02-8002 V001 V
Acrylonitrile34215107-13-1003 V002 V
Benzene3403071-43-2004 V003 V
Bromodichloromethane3210175-27-4048 V012 V
Bromoform3210475-25-2047 V005 V
Bromomethane3441374-83-9046 V020 V
Carbon tetrachloride3210256-23-5006 V006 V
Chlorobenzene34301108-90-7007 V007 V
Chloroethane3431175-00-3016 V009 V
2-chloroethylvinyl ether34576110-75-8019 V010 V
Chloroform3210667-66-1023 V011 V
Chloromethane3441874-87-3045 V021 V
Dibromochloromethane32105124-48-1051 V008 V
1,1-dichloroethane3449675-34-3013 V014 V
1,2-dichloroethane34536107-06-2010 V015 V
1,1-dichloroethene3450175-35-4029 V016 V
Trans-1,2-dichloroethane34546156-60-5030 V026 V
1,2-dichloropropane3454178-87-5032 V017 V
Cis-1,3-dichloropropene3470410061-01-5
Trans-1,3-dichloropropene3469910061-02-6033 V
Diethyl ether8157660-29-7515 V
P-dioxane81582123-91-1527 V
Ethylbenzene34371100-41-4038 V019 V
Methylene chloride3442375-09-2044 V022 V
Methyl ethyl ketone8159578-93-3514 V
1,1,2,2-tetrachloroethane3451679-34-5015 V023 V
Tetrachlorethene34475127-18-4085 V024 V
Toluene34010108-88-3086 V025 V
1,1,1-trichloroethane3450671-55-6011 V027 V
1,1,2-trichloroethane3451179-00-5014 V028 V
Trichloroethene3918079-01-6087 V029 V
Vinyl chloride3917575-01-4088 V031 V

Table 2—Gas Chromatography of Purgeable Organic Compounds by Isotope Dilution GC/MS

EGD No. (1)
Compound
Ref EGD No.
Mean retention time (sec)
Minimum level (2) (µg/L)
181Bromochloromethane (I.S.)18173010
245Chloromethane-d318114750
345Chloromethane24514850
246Bromomethane-d318124350
346Bromomethane24624650
288Vinyl chloride-d318130150
388Vinyl chloride28830410
216Chloroethane-d518137850
316Chloroethane21638650
244Methylene chloride-d218151210
344Methylene chloride24451710
616Acetone-d618155450
716Acetone61656550
002Acrolein18156650
203Acrylonitrile-d318160650
303Acrylonitrile20361250
2291,1-dichloroethene-d218169610
3291,1-dichloroethene22969610
2131,1-dichloroethane-d318177810
3131,1-dichloroethane21378610
615Diethyl ether-d1018180450
715Diethyl ether61582050
230Trans-1,2-dichloroethene-d218182110
330Trans-1,2-dichloroethene23082110
614Methyl ethyl ketone-d318184050
714Methyl ethyl ketone61484850
223Chloroform-13C118186110
323Chloroform22386110
2101,2-dichloroethane-d418190110
3101,2-dichloroethane21091010
2111,1,1-trichloroethane-13C218198910
3111,1,1-trichloroethane21199910
527p-dioxane181100110
206Carbon tetrachloride-13C1182101810
306Carbon tetrachloride206101810
248Bromodichloromethane-13C1182104510
348Bromodichloromethane248104510
2321,2-dichloropropane-d6182112310
3321.2-dichloropropane232113410
233Trans-1,3-dichloropropene-d4182113810
333Trans-1,3-dichloropropene233113810
287Trichloroethene-13C1182117210
387Trichloroethene287118710
204Benzene-d6182120010
304Benzene204121210
251Chlorodibromemethane-13C1182122210
351Chlorodibromomethane251122210
2141,1,2-trichloroethane-13C2182122410
3141,1,2-trichloroethane214122410
0192-chloroethylvinyl ether182127810
1822-bromo-1-chloropropane (I.S.)182130610
247Bromoform-13C1182138610
347Bromoform247138610
2151,1,2,2-tetrachloroethane-d2183152510
3151,1,2,2-tetrachloroethane215152510
285Tetrachloroethene-13C2183152810
385Tetrachloroethene285152810
1831,4-dichlorobutale (int std)183155510
286Toluene-d8183160310
386Toluene286161910
207Chlorobenzene-d5183167910
307Chlorobenzene207167910
238Ethylbenzene-d10183180210
338Ethylbenzene238182010
185Bromofluorobenzene183198510

(1) Reference numbers beginning with 0, 1 or 5 indicate a pollutant quantified by the internal standard method; reference numbers beginning with 2 or 6 indicate a labeled compound quantified by the internal standard method; reference numbers beginning with 3 or 7 indicate a pollutant quantified by isotope dilution.

(2) This is a minimum level at which the analytical system shall give recognizable mass spectra (background corrected) and acceptable calibration points. Column: 2.4m (8 ft) × 2 mm i.d. glass, packed with one percent SP-1000 coated on 60/80 Carbopak B. Carrier gas: helium at 40 mL/min. Temperature program: 3 min at 45 °C, 8 °C per min to 240 °C, hold at 240 °C for 15 minutes.

Note: The specifications in this table were developed from data collected from three wastewater laboratories.


Table 3—BFB Mass-Intensity Specifications

Mass
Intensity required
5015 to 40 percent of mass 95.
7530 to 60 percent of mass 95.
95base peak, 100 percent.
965 to 9 percent of mass 95.
173
174>50 percent of mass 95.
1755 to 9 percent of mass 174
17695 to 101 percent of mass 174
1775 to 9 percent of mass 176.

Table 4—Volatile Organic Compound Characteristic Masses

Labeled compound
Analog
Primary m/z’s
Acetoned658/64
Acroleind256/58
Acrylonitriled353/56
Benzened678/84
Bromodichloromethane13C83/86
Bromoform13C173/176
Bromomethaled396/99
Carbon tetrachloride13C47/48
Chlorobenzened5112/117
Chloroethaned564/71
2-chloroethylvinyl etherd7106/113
Chloroform13C85/86
Chloromethaned350/53
Dibromochloromethane13C129/130
1,1-dichloroethaned363/66
1,2-dichloroethaned462/67
1,1-dichloroethened261/65
Trans-1,2-dichloroethened261/65
1,2-dichloropropaned663/67
Cis-1,3-dichloropropened475/79
Trans-1,3-dichloropropened475/79
Diethyl etherd1074/84
p-dioxaned888/96
Ethylbenzened10106/116
Methylene chlorided284/88
Methyl ethyl ketoned372/75
1,1,2,2-tetrachloroethaned283/84
Tetrachloroethene13C2166/172
Toluened892/99
1,1,1-trichloroethaned397/102
1,1,2-trichloroethane13C283/84
Trichloroethene13C95/133
Vinyl chlorided362/65

Table 5—Acceptance Criteria for Performance Tests

Compound
Acceptance criteria at 20 µg/L
Initial precision and accuracy section 8.2.3
Labeled compound recovery sec. 8.3 and 14.2
On-going accuracy sec. 11.5
s (µg/L)
X
(µg/L)
P (percent)
R (µg/L)
AcetoneNote 1
AcroleinNote 2
AcrylonitrileNote 2
Benzene9.013.0-28.2ns-1964-33
Bromodichloromethane8.26.5-31.5ns-1994-34
Bromoform7.07.4-35.1ns-2146-36
Bromomethane25.0d-54.3ns-414d-61
Carbon tetrachloride6.915.9-24.842-16512-30
Chlorobenzene8.214.2-29.6ns-2054-35
Chloroethane14.82.1-46.7ns-308d-51
2-chloroethylvinyl ether36.0d-69.8ns-554d-79
Chloroform7.911.6-26.318-1728-30
Chloromethane26.0d-55.5ns-410d-64
Dibromochloromethane7.911.2-29.116-1858-32
1,1-dichloroethane6.711.4-31.423-1919-33
1,2-dichloroethane7.711.6-30.112-1928-33
1,1-dichloroethene11.7d-49.8ns-315d-52
Trans-1,2-dichloroethene7.410.5-31.515-1958-34
1,2-dichloropropane19.2d-46.8ns-343d-51
Cis-1,3-dichloropropene22.1d-51.0ns-381d-56
Trans-1,3-dichloropropene14.5d-40.2ns-284d-44
Diethyl etherNote 1
P-dioxaneNote 1
Ethyl benzene9.615.6-28.5ns-2035-35
Methylene chloride9.7d-49.8ns-316d-50
Methyl ethyl ketoneNote 1
1,1,2,2-tetrachloroethane9.610.7-30.05-1997-34
Tetrachloroethene6.615.1-28.531-18111-32
Toluene6.314.5-28.74-1936-33
1,1,1-trichloroethane5.910.5-33.412-2008-35
1,1,2-trichloroethane7.111.8-29.721-1849-32
Trichloroethene8.916.6-29.535-19612-34
Vinyl chloride27.9d-58.5ns-452d-65

d = detected; result must be greater than zero.

ns = no specification; limit would be below detection limit.

Note 1: Specifications not available for these compounds at time of release of this method.

Note 2: Specifications not developed for these compounds; use method 603.




Method 1625 Revision B—Semivolatile Organic Compounds by Isotope Dilution GC/MS


1. Scope and Application

1.1 This method is designed to determine the semivolatile toxic organic pollutants associated with the 1976 Consent Decree and additional compounds amenable to extraction and analysis by capillary column gas chromatography-mass spectrometry (GC/MS).


1.2 The chemical compounds listed in Tables 1 and 2 may be determined in municipal and industrial discharges by this method. The method is designed to meet the survey requirements of Effluent Guidelines Division (EGD) and the National Pollutants Discharge Elimination System (NPDES) under 40 CFR 136.1. Any modifications of this method, beyond those expressly permitted, shall be considered as major modifications subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.


1.3 The detection limit of this method is usually dependent on the level of interferences rather than instrumental limitations. The limits listed in Tables 3 and 4 represent the minimum quantity that can be detected with no interferences present.


1.4 The GC/MS portions of this method are for use only by analysts experienced with GC/MS or under the close supervision of such qualified persons. Laboratories unfamiliar with analyses of environmental samples by GC/MS should run the performance tests in reference 1 before beginning.


2. Summary of Method

2.1 Stable isotopically labeled analogs of the compounds of interest are added to a one liter wastewater sample. The sample is extracted at pH 12-13, then at pH

2.2 Identification of a compound (qualitative analysis) is performed by comparing the GC retention time and background corrected characteristic spectral masses with those of authentic standards.


2.3 Quantitative analysis is performed by GC/MS using extracted ion current profile (EICP) areas. Isotope dilution is used when labeled compounds are available; otherwise, an internal standard method is used.


2.4 Quality is assured through reproducible calibration and testing of the extraction and GC/MS systems.


3. Contamination and Interferences

3.1 Solvents, reagents, glassware, and other sample processing hardware may yield artifacts and/or elevated baselines causing misinterpretation of chromatograms and spectra. All materials shall be demonstrated to be free from interferences under the conditions of analysis by running method blanks initially and with each sample lot (samples started through the extraction process on a given 8 hr shift, to a maximum of 20). Specific selection of reagents and purification of solvents by distillation in all-glass systems may be required. Glassware and, where possible, reagents are cleaned by solvent rinse and baking at 450 °C for one hour minimum.


3.2 Interferences coextracted from samples will vary considerably from source to source, depending on the diversity of the industrial complex or municipality being samples.


4. Safety

4.1 The toxicity or carcinogenicity of each compound or reagent used in this method has not been precisely determined; however, each chemical compound should be treated as a potential health hazard. Exposure to these compounds should be reduced to the lowest possible level. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of data handling sheets should also be made available to all personnel involved in these analyses. Additional information on laboratory safety can be found in references 2-4.


4.2 The following compounds covered by this method have been tentatively classified as known or suspected human or mammalian carcinogens: benzidine benzo(a)anthracene, 3,3′-dichlorobenzidine, benzo(a)pyrene, dibenzo(a,h)anthracene, N-nitrosodimethylamine, and β-naphtylamine. Primary standards of these compounds shall be prepared in a hood, and a NIOSH/MESA approved toxic gas respirator should be worn when high concentrations are handled.


5. Apparatus and Materials

5.1 Sampling equipment for discrete or composite sampling.


5.1.1 Sample bottle, amber glass, 1.1 liters minimum. If amber bottles are not available, samples shall be protected from light. Bottles are detergent water washed, then solvent rinsed or baked at 450 °C for one hour minimum before use.


5.1.2 Bottle caps—threaded to fit sample bottles. Caps are lined with Teflon. Aluminum foil may be substituted if the sample is not corrosive. Liners are detergent water washed, then reagent water (Section 6.5) and solvent rinsed, and baked at approximately 200 °C for one hour minimum before use.


5.1.3 Compositing equipment—automatic or manual compositing system incorporating glass containers for collection of a minimum 1.1 liters. Sample containers are kept at 0 to 4 °C during sampling. Glass or Teflon tubing only shall be used. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used in the pump only. Before use, the tubing is thoroughly rinsed with methanol, followed by repeated rinsings with reagent water (Section 6.5) to minimize sample contamination. An integrating flow meter is used to collect proportional composite samples.


5.2 Continuous liquid-liquid extractor—Teflon or glass conncecting joints and stopcocks without lubrication (Hershberg-Wolf Extractor) one liter capacity, Ace Glass 6841-10, or equivalent.


5.3 Drying column—15 to 20 mm i.d. Pyrex chromatographic column equipped with coarse glass frit or glass wool plug.


5.4 Kuderna-Danish (K-D) apparatus


5.4.1 Concentrator tube—10mL, graduated (Kontes K-570050-1025, or equivalent) with calibration verified. Ground glass stopper (size 19/22 joint) is used to prevent evaporation of extracts.


5.4.2 Evaporation flask—500 mL (Kontes K-570001-0500, or equivalent), attached to concentrator tube with springs (Kontes K-662750-0012).


5.4.3 Snyder column—three ball macro (Kontes K-503000-0232, or equivalent).


5.4.4 Snyder column—two ball micro (Kontes K-469002-0219, or equivalent).


5.4.5 Boiling chips—approx 10/40 mesh, extracted with methylene chloride and baked at 450 °C for one hr minimum.


5.5 Water bath—heated, with concentric ring cover, capable of temperature control ±2 °C, installed in a fume hood.


5.6 Sample vials—amber glass, 2-5 mL with Teflon-lined screw cap.


5.7 Analytical balance—capable of weighing 0.1 mg.


5.8 Gas chromatograph—shall have splitless or on-column injection port for capillary column, temperature program with 30 °C hold, and shall meet all of the performance specifications in Section 12.


5.8.1 Column—30 ±5 m × 0.25 ±0.02 mm i.d. 5% phenyl, 94% methyl, 1% vinyl silicone bonded phase fused silica capillary column (J & W DB-5, or equivalent).


5.9 Mass spectrometer—70 eV electron impact ionization, shall repetitively scan from 35 to 450 amu in 0.95 to 1.00 second, and shall produce a unit resolution (valleys between m/z 441-442 less than 10 percent of the height of the 441 peak), backgound corrected mass spectrum from 50 ng decafluorotriphenylphosphine (DFTPP) introduced through the GC inlet. The spectrum shall meet the mass-intensity criteria in Table 5 (reference 5). The mass spectrometer shall be interfaced to the GC such that the end of the capillary column terminates within one centimeter of the ion source but does not intercept the electron or ion beams. All portions of the column which connect the GC to the ion source shall remain at or above the column temperature during analysis to preclude condensation of less volatile compounds.


5.10 Data system—shall collect and record MS data, store mass-intensity data in spectral libraries, process GC/MS data, generate reports, and shall compute and record response factors.


5.10.1 Data acquisition—mass spectra shall be collected continuously throughout the analysis and stored on a mass storage device.


5.10.2 Mass spectral libraries—user created libraries containing mass spectra obtained from analysis of authentic standards shall be employed to reverse search GC/MS runs for the compounds of interest (Section 7.2).


5.10.3 Data processing—the data system shall be used to search, locate, identify, and quantify the compounds of interest in each GC/MS analysis. Software routines shall be employed to compute retention times and peak areas. Displays of spectra, mass chromatograms, and library comparisons are required to verify results.


5.10.4 Response factors and multipoint calibrations—the data system shall be used to record and maintain lists of response factors (response ratios for isotope dilution) and multipoint calibration curves (Section 7). Computations of relative standard deviation (coefficient of variation) are useful for testing calibration linearity. Statistics on initial (Section 8.2) and on-going (Section 12.7) performance shall be computed and maintained.


6. Reagents and Standards

6.1 Sodium hydroxide—reagent grade, 6N in reagent water.


6.2 Sulfuric acid—reagent grade, 6N in reagent water.


6.3 Sodium sulfate—reagent grade, granular anhydrous, rinsed with methylene chloride (20 mL/g) and conditioned at 450 °C for one hour minimum.


6.4 Methylene chloride—distilled in glass (Burdick and Jackson, or equivalent).


6.5 Reagent water—water in which the compounds of interest and interfering compounds are not detected by this method.


6.6 Standard solutions—purchased as solutions or mixtures with certification to their purity, concentration, and authenticity, or prepared from materials of known purity and composition. If compound purity is 96 percent or greater, the weight may be used without correction to compute the concentration of the standard. When not being used, standards are stored in the dark at −20 to −10 °C in screw-capped vials with Teflon-lined lids. A mark is placed on the vial at the level of the solution so that solvent evaporation loss can be detected. The vials are brought to room temperature prior to use. Any precipitate is redissolved and solvent is added if solvent loss has occurred.


6.7 Preparation of stock solutions—prepare in methylene chloride, benzene, p-dioxane, or a mixture of these solvents per the steps below. Observe the safety precautions in Section 4. The large number of labeled and unlabeled acid, base/neutral, and Appendix C compounds used for combined calibration (Section 7) and calibration verification (12.5) require high concentratimns (approx 40 mg/mL) when individual stock solutions are prepared, so that dilutions of mixtures will permit calibration with all compounds in a single set of solutions. The working range for most compounds is 10-200 µg/mL. Compounds with a reduced MS response may be prepared at higher concentrations.


6.7.1 Dissolve an appropriate amount of assayed reference material in a suitable solvent. For example, weigh 400 mg naphthalene in a 10 mL ground glass stoppered volumetric flask and fill to the mark with benzene. After the naphthalene is completely dissolved, transfer the solution to a 15 mL vial with Teflon-lined cap.


6.7.2 Stock standard solutions should be checked for signs of degradation prior to the preparation of calibration or performance test standards. Quality control check samples that can be used to determine the accuracy of calibration standards are available from the US Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268.


6.7.3 Stock standard solutions shall be replaced after six months, or sooner if comparison with quality control check samples indicates a change in concentration.


6.8 Labeled compound spiking solution—from stock standard solutions prepared as above, or from mixtures, prepare the spiking solution at a concentration of 200 µg/mL, or at a concentration appropriate to the MS response of each compound.


6.9 Secondary standard—using stock solutions (Section 6.7), prepare a secondary standard containing all of the compounds in Tables 1 and 2 at a concentration of 400 µg/mL, or higher concentration appropriate to the MS response of the compound.


6.10 Internal standard solution—prepare 2,2′-difluorobiphenyl (DFB) at a concentration of 10 mg/mL in benzene.


6.11 DFTPP solution—prepare at 50 µg/mL in acetone.


6.12 Solutions for obtaining authentic mass spectra (Section 7.2)—prepare mixtures of compounds at concentrations which will assure authentic spectra are obtained for storage in libraries.


6.13 Calibration solutions—combine 0.5 mL of the solution in Section 6.8 with 25, 50, 125, 250, and 500 uL of the solution in section 6.9 and bring to 1.00 mL total volume each. This will produce calibration solutions of nominal 10, 20, 50, 100, and 200 µg/mL of the pollutants and a constant nominal 100 µg/mL of the labeled compounds. Spike each solution with 10 µL of the internal standard solution (Section 6.10). These solutions permit the relative response (labeled to unlabeled) to be measured as a function of concentration (Section 7.4).


6.14 Precision and recovery standard—used for determination of initial (Section 8.2) and on-going (Section 12.7) precision and recovery. This solution shall contain the pollutants and labeled compounds at a nominal concentration of 100 µg/mL.


6.15 Stability of solutions—all standard solutions (Sections 6.8-6.14) shall be analyzed within 48 hours of preparation and on a monthly basis thereafter for signs of degradation. Standards will remain acceptable if the peak area at the quantitation mass relative to the DFB internal standard remains within ±15 percent of the area obtained in the initial analysis of the standard.


7. Calibration

7.1 Assemble the GC/MS and establish the operating conditions in Table 3. Analyze standards per the procedure in Section 11 to demonstrate that the analytical system meets the detection limits in Tables 3 and 4, and the mass-intensity criteria in Table 5 for 50 ng DFTPP.


7.2 Mass spectral libraries—detection and identification of compounds of interest are dependent upon spectra stored in user created libraries.


7.2.1 Obtain a mass spectrum of each pollutant, labeled compound, and the internal standard by analyzing an authentic standard either singly or as part of a mixture in which there is no interference between closely eluted components. That only a single compound is present is determined by examination of the spectrum. Fragments not attributable to the compound under study indicate the presence of an interfering compound.


7.2.2 Adjust the analytical conditions and scan rate (for this test only) to produce an undistorted spectrum at the GC peak maximum. An undistorted spectrum will usually be obtained if five complete spectra are collected across the upper half of the GC peak. Software algorithms designed to “enhance” the spectrum may eliminate distortion, but may also eliminate authentic masses or introduce other distortion.


7.2.3 The authentic reference spectrum is obtained under DFTPP tuning conditions (Section 7.1 and Table 5) to normalize it to spectra from other instruments.


7.2.4 The spectrum is edited by saving the 5 most intense mass spectral peaks and all other mass spectral peaks greater than 10 percent of the base peak. This edited spectrum is stored for reverse search and for compound confirmation.


7.3 Analytical range—demonstrate that 20 ng anthracene or phenanthrene produces an area at m/z 178 approx one-tenth that required to exceed the linear range of the system. The exact value must be determined by experience for each instrument. It is used to match the calibration range of the instrument to the analytical range and detection limits required, and to diagnose instrument sensitivity problems (Section 15.4). The 20 ug/mL calibration standard (Section 6.13) can be used to demonstrate this performance.


7.3.1 Polar compound detection—demonstrate that unlabeled pentachlorophenol and benzidine are detectable at the 50 µg/mL level (per all criteria in Section 13). The 50 µg/mL calibration standard (Section 6.13) can be used to demonstrate this performance.


7.4 Calibration with isotope dilution—isotope dilution is used when (1) labeled compounds are available, (2) interferences do not preclude its use, and (3) the quantitation mass extracted ion current profile (EICP) area for the compound is in the calibration range. If any of these conditions preclude isotope dilution, internal standard methods (Section 7.5 or 7.6) are used.


7.4.1 A calibration curve encompassing the concentration range is prepared for each compound to be determined. The relative response (pollutant to labeled) vs concentration in standard solutions is plotted or computed using a linear regression. The example in Figure 1 shows a calibration curve for phenol using phenol-d5 as the isotopic diluent. Also shown are the ±10 percent error limits (dotted lines). Relative Reponse (RR) is determined according to the procedures described below. A minimum of five data points are employed for calibration.


7.4.2 The relative response of a pollutant to its labeled analog is determined from isotope ratio values computed from acquired data. Three isotope ratios are used in this process:


RX = the isotope ratio measured for the pure pollutant.


Ry = the isotope ratio measured for the labeled compound.


Rm = the isotope ratio of an analytical mixture of pollutant and labeled compounds.


The m/z’s are selected such that RX>Ry. If Rm is not between 2Ry and 0.5RX, the method does not apply and the sample is analyzed by internal or external standard methods.


7.4.3 Capillary columns usually separate the pollutant-labeled pair, with the labeled compound eluted first (Figure 2). For this case, RX = [area m1/z]/1, at the retention time of the pollutant (RT2). Ry = 1/[area m2/z, at the retention time of the labeled compound RT1). Rm = [area at m1/z (at RT2)]/[area at RT1)], as measured in the mixture of the pollutant and labeled compounds (Figure 2), and RR = Rm.


7.4.4 Special precautions are taken when the pollutant-labeled pair is not separated, or when another labeled compound with interfering spectral masses overlaps the pollutant (a case which can occur with isomeric compounds). In this case, it is necessary to determine the respective contributions of the pollutant and labeled compounds to the respective EICP areas. If the peaks are separated well enough to permit the data system or operator to remove the contributions of the compounds to each other, the equations in Section 7.4.3 apply. This usually occurs when the height of the valley between the two GC peaks at the same m/z is less than 10 percent of the height of the shorter of the two peaks. If significant GC and spectral overlap occur, RR is computed using the following equation:


RR = (Ry − Rm) (RX + 1)/(Rm − RX) (Ry + 1), where RX is measured as shown in Figure 3A, Ry is measured as shown in Figure 3B, and Rm is measured as shown in Figure 3C. For example, RX = 46100/4780 = 9.644, Ry = 2650/43600 = 0.0608, Rm = 49200/48300 = 1.019. amd RR = 1.114.


7.4.5 To calibrate the analytical system by isotope dilution, analyze a 1.0 µL aliquot of each of the calibration standards (Section 6.13) using the procedure in Section 11. Compute the RR at each concentration.


7.4.6 Linearity—if the ratio of relative response to concentration for any compound is constant (less than 20 percent coefficient of variation) over the 5 point calibration range, and averaged relative response/concentration ratio may be used for that compound; otherwise, the complete calibration curve for that compound shall be used over the 5 point calibration range.


7.5 Calibration by internal standard—used when criteria for istope dilution (Section 7.4) cannot be met. The internal standard to be used for both acid and base/neutral analyses is 2,2′-difluorobiphenyl. The internal standard method is also applied to determination of compounds having no labeled analog, and to measurement of labeled compounds for intra-laboratory statistics (Sections 8.4 and 12.7.4).


7.5.1 Response factors—calibration requires the determination of response factors (RF) which are defined by the following equation:


RF = (As × Cis)/(Ais × Cs), where

As is the area of the characteristic mass for the compmund in the daily standard

Ais is the area of the characteristic mass for the internal standard

Cis is the concentration of the internal standard (µg/mL)

Cs is the concentration of the compound in the daily standard (µg/mL)

7.5.1.1 The response factor is determined for at least five concentrations appropriate to the response of each compound (Section 6.13); nominally, 10, 20, 50, 100, and 200 µg/mL. The amount of internal standard added to each extract is the same (100 µg/mL) so that Cis remains constant. The RF is plotted vs concentration for each compound in the standard (Cs) to produce a calibration curve.


7.5.1.2 Linearity—if the response factor (RF) for any compound is constant (less than 35 percent coefficient of variation) over the 5 point calibration range, an averaged response factor may be used for that compound; otherwise, the complete calibration curve for that compound shall be used over the 5 point range.


7.6 Combined calibration—by using calibration solutions (Section 6.13) containing the pollutants, labeled compounds, and the internal standard, a single set of analyses can be used to produce calibration curves for the isotope dilution and internal standard methods. These curves are verified each shift (Section 12.5) by analyzing the 100 µg/mL calibration standard (Section 6.13). Recalibration is required only if calibration verification (Section 12.5) criteria cannot be met.


8. Quality Assurance/Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability, analysis of samples spiked with labeled compounds to evaluate and document data quality, and analysis of standards and blanks as tests of continued performance. Laboratory performance is compared to established performance criteria to determine if the results of analyses meet the performance characteristics of the method.


8.1.1 The analyst shall make an initial demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.


8.1.2 The analyst is permitted to modify this method to improve separations or lower the costs of measurements, provided all performance specifications are met. Each time a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2 to demonstrate method performance.


8.1.3 Analyses of blanks are required to demonstrate freedom from contamination. The procedures and criteria for analysis of a blank are described in Section 8.5.


8.1.4 The laboratory shall spike all samples with labeled compounds to monitor method performance. This test is described in Section 8.3. When results of these spikes indicate atypical method performance for samples, the samples are diluted to bring method performance within acceptable limits (Section 15).


8.1.5 The laboratory shall, on an on-going basis, demonstrate through calibration verification and the analysis of the precision and recovery standard (Section 6.14) that the analysis system is in control. These procedures are described in Sections 12.1, 12.5, and 12.7.


8.1.6 The laboratory shall maintain records to define the quality of data that is generated. Development of accuracy statements is described in Section 8.4.


8.2 Initial precision and accuracy—to establish the ability to generate acceptable precision and accuracy, the analyst shall perform the following operations:


8.2.1 Extract, concentrate, and analyze two sets of four one-liter aliquots (8 aliquots total) of the precision and recovery standard (Section 6.14) according to the procedure in Section 10.


8.2.2 Using results of the first set of four analyses, compute the average recovery (X
) in µg/mL and the standard deviation of the recovery (s) in θg/µL for each compound, by isotope dilution for pollutants with a labeled analog, and by internal standard for labeled compounds and pollutants with no labeled analog.


8.2.3 For each compound, compare s and X
with the corresponding limits for initial precision and accuracy in Table 8. If s and X
for all compounds meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may begin. If, however, any individual s exceeds the precision limit or any individual X
falls outside the range for accuracy, system performance is unacceptable for that compound.



Note:

The large number of compounds in Table 8 present a substantial probability that one or more will fail the acceptance criteria when all compounds are analyzed. To determine if the analytical system is out of control, or if the failure can be attributed to probability, proceed as follows:


8.2.4 Using the results of the second set of four analyses, compute s and X
for only those compounds which failed the test of the first set of four analyses (Section 8.2.3). If these compounds now pass, system performance is acceptable for all compounds and analysis of blanks and samples may begin. If, however, any of the same compoulds fail again, the analysis system is not performing properly for these compounds. In this event, correct the problem and repeat the entire test (Section 8.2.1).


8.3 The laboratory shall spike all samples with labeled compounds to assess method performance on the sample matrix.


8.3.1 Analyze each sample according to the method in Section 10.


8.3.2 Compute the percent recovery (P) of the labeled compounds using the internal standard methmd (Section 7.5).


8.3.3 Compare the labeled compound recovery for each compound with the corresponding limits in Table 8. If the recovery of any compounds falls outside its warning limit, method performance is unacceptable for that compound in that sample, Therefore, the sample is complex and is to be diluted and reanalyzed per Section 15.4.


8.4 As part of the QA program for the laboratory, method accuracy for wastewater samples shall be assessed and records shall be maintained. After the analysis of five wastewater samples for which the labeled compounds pass the tests in Section 8.3, compute the average percent recovery (P) and the standard deviation of the percent recovery (sp) for the labeled compounds only. Express the accuracy assessment as a percent recovery interval from P—2 sp to P + 2sp. For example, if P = 90% and sp = 10%, the accuracy interval is expressed as 70-100%. Update the accuracy assessment for each compound on a regular basis (e.g. after each 5-10 new accuracy measurements).


8.5 Blanks—reagent water blanks are analyzed to demonstrate freedom from contamination.


8.5.1 Extract and concentrate a blank with each sample lot (samples started through the extraction process on the same 8 hr shift, to a maximum of 20 samples). Analyze the blank immediately after analysis of the precision and recovery standard (Section 6.14) to demonstrate freedom from contamination.


8.5.2 If any of the compounds of interest (Tables 1 and 2) or any potentially interfering compound is found in a blank at greater than 10 µg/L (assuming a response factor of 1 relative to the internal standard for compounds not listed in Tables 1 and 2), analysis of samples is halted until the source of contamination is eliminated and a blank shows no evidence of contamination at this level.


8.6 The specifications contained in this method can be met if the apparatus used is calibrated properly, then maintained in a calibrated state. The standards used for calibration (Section 7), calibration verification (Section 12.5), and for initial (Section 8.2) and on-going (Section 12.7) precision and recovery should be identical, so that the most precise results will be obtained. The GC/MS instrument in particular will provide the most reproducible results if dedicated to the settings and conditions required for the analysis of semi-volatiles by this method.


8.7 Depending on specific program requirements, field replicates may be collected to determine the precision of the sampling technique, and spiked samples may be required to determine the accuracy of the analysis when internal or external standard methods are used.


9. Sample Collection, Preservation, and Handling

9.1 Collect samples in glass containers following conventional sampling practices (Reference 7). Composite samples are collected in refrigerated glass containers (Section 5.1.3) in accordance with the requirements of the sampling program.


9.2 Maintain samples at 0-4 °C from the time collectimn until extraction. If residual chlorine is present, add 80 mg sodium thiosulfate per liter of water. EPA Methods 330.4 and 330.5 may be used to measure residual chlorine (Reference 8).


9.3 Begin sample extraction within seven days of collection, and analyze all extracts within 40 days of extraction.


10. Sample Extraction and Concentration (See Figure 4)

10.1 Labeled compound spiking—measure 1.00 ±0.01 liter of sample into a glass container. For untreated effluents, and samples which are expected to be difficult to extract and/or concentrate, measure an additional 10.0 ±0.1 mL and dilute to a final volume of 1.00 ±0.01 liter with reagent water in a glass container.


10.1.1 For each sample or sample lot (to a maximum of 20) to be extracted at the same time, place three 1.00 ±0.10 liter aliquots of reagent water in glass containers.


10.1.2 Spike 0.5 mL of the labeled compound spiking solution (Section 6.8) into all samples and one reagant water aliquot.


10.1.3 Spike 1.0 mL of the precision and recovery standard (Section 6.14) into the two remaining reagent water aliquots.


10.1.4 Stir and equilibrate all solutions for 1-2 hr.


10.2 Base/neutral extraction—place 100-150 mL methylene chloride in each continuous extractor and 200-300 in each distilling flask.


10.2.1 Pour the sample(s), blank, and standard aliquots into the extractors. Rinse the glass containers with 50-100 mL methylene chloride and add to the respective extractor.


10.2.2 Adjust the pH of the waters in the extractors to 12-13 with 6N NaOH while monitoring with a pH meter. Begin the extraction by heating the flask until the methylene chloride is boiling. When properly adjusted, 1-2 drops of methylene chloride per second will fall from the condensor tip into the water. After 1-2 hours of extraction, test the pH and readjust to 12-13 if required. Extract for 18-24 hours.


10.2.3 Remove the distilling flask, estimate and record the volume of extract (to the nearest 100 mL), and pour the contents through a drying column containing 7 to 10 cm anhydrous sodium sulfate. Rinse the distilling flask with 30-50 mL of methylene chloride and pour through the drying column. Collect the solution in a 500 mL K-D evaporator flask equipped with a 10 mL concentrator tube. Seal, label as the base/neutral fraction, and concentrate per Sections 10.4 to 10.5.


10.3 Acid extraction—adjust the pH of the waters in the extractors to 2 or less using 6N sulfuric acid. Charge clean distilling flasks with 300-400 mL of methylene chloride. Test and adjust the pH of the waters after the first 1-2 hr of extraction. Extract for 18-24 hours.


10.3.1 Repeat Section 10.2.3, except label as the acid fraction.


10.4 Concentration—concentrate the extracts in separate 500 mL K-D flasks equipped with 10 mL concentrator tubes.


10.4.1 Add 1 to 2 clean boiling chips to the flask and attach a three-ball macro Snyder column. Prewet the column by adding approximately one mL of methylene chloride through the top. Place the K-D apparatus in a hot water bath so that the entire lower rounded surface of the flask is bathed with steam. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 minutes. At the proper rate of distillation, the balls of the column will actively chatter but the chambers will not flood. When the liquid has reached an apparent volume of 1 mL, remove the K-D apparatus from the bath and allow the solvent to drain and cool for at least 10 minutes. Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1-2 mL of methylene chloride. A 5-mL syringe is recommended for this operation.


10.4.2 For performance standards (Sections 8.2 and 12.7) and for blanks (Section 8.5), combine the acid and base/neutral extracts for each at this point. Do not combine the acid and base/neutral extracts for samples.


10.5 Add a clean boiling chip and attach a two ball micro Snyder column to the concentrator tube. Prewet the column by adding approx 0.5 mL methylene chloride through the top. Place the apparatus in the hot water bath. Adjust the vertical position and the water temperature as required to complete the concentration in 5-10 minutes. At the proper rate of distillation, the balls of the column will actively chatter but the chambers will not flood. When the liquid reaches an apparent volume of approx 0.5 mL, remove the apparatus from the water bath and allow to drain and cool for at least 10 minutes. Remove the micro Snyder column and rinse its lower joint into the concentrator tube with approx 0.2 mL of methylene chloride. Adjust the final volume to 1.0 mL.


10.6 Transfer the concentrated extract to a clean screw-cap vial. Seal the vial with a Teflon-lined lid, and mark the level on the vial. Label with the sample number and fraction, and store in the dark at −20 to −10 °C until ready for analysis.


11. GC/MS Analysis

11.1 Establish the operating conditions given in Table 3 or 4 for analysis of the base/neutral or acid extracts, respectively. For analysis of combined extracts (Section 10.4.2), use the operating conditions in Table 3.


11.2 Bring the concentrated extract (Section 10.6) or standard (Sections 6.13 through 6.14) to room temperature and verify that any precipitate has redissolved. Verify the level on the extract (Sections 6.6 and 10.6) and bring to the mark with solvent if required.


11.3 Add the internal standard solution (Section 6.10) to the extract (use 1.0 uL of solution per 0.1 mL of extract) immediately prior to injection to minimize the possibility of loss by evaporation, adsorption, or reaction. Mix thoroughly.


11.4 Inject a volume of the standard solution or extract such that 100 ng of the internal standard will be injected, using on-column or splitless injection. For 1 mL extracts, this volume will be 1.0 uL. Start the GC column initial isothermal hold upon injection. Start MS data collection after the solvent peak elutes. Stop data collection after the benzo (ghi) perylene or pentachlorophenol peak elutes for the base/neutral or acid fraction, respectively. Return the column to the initial temperature for analysis of the next sample.


12. System and Laboratory Performance

12.1 At the beginning of each 8 hr shift during which analyses are performed, GC/MS system performance and calibration are verified for all pollutants and labeled compounds. For these tests, analysis of the 100 µg/mL calibration standard (Section 6.13) shall be used to verify all performance criteria. Adjustment and/or recalibration (per Section 7) shall be performed until all performance criteria are met. Only after all performance criteria are met may samples, blanks, and precision and recovery standards be analyzed.


12.2 DFTPP spectrum validity—inject 1 µL of the DFTPP solution (Section 6.11) either separately or within a few seconds of injection of the standard (Section 12.1) analyzed at the beginning of each shift. The criteria in Table 5 shall be met.


12.3 Retention times—the absolute retention time of 2,2′-difluorobiphenyl shall be within the range of 1078 to 1248 seconds and the relative retention times of all pollutants and labeled compounds shall fall within the limits given in Tables 3 and 4.


12.4 GC resolution—the valley height between anthracene and phenanthrene at m/z 178 (or the analogs at m/z 188) shall not exceed 10 percent of the taller of the two peaks.


12.5 Calibration verification—compute the concentration of each pollutant (Tables 1 and 2) by isotope dilution (Section 7.4) for those compounds which have labeled analogs. Compute the concentration of each pollutant which has no labeled analog by the internal standard method (Section 7.5). Compute the concentration of the labeled compounds by the internal standard method. These concentrations are computed based on the calibration data determined in Section 7.


12.5.1 For each pollutant and labeled compound being tested, compare the concentration with the calibration verification limit in Table 8. If all compounds meet the acceptance criteria, calibration has been verified and analysis of blanks, samples, and precision and recovery standards may proceed. If, however, any compound fails, the measurement system is not performing properly for that compound. In this event, prepare a fresh calibration standard or correct the problem causing the failure and repeat the test (Section 12.1), or recalibrate (Section 7).


12.6 Multiple peaks—each compound injected shall give a single, distinct GC peak.


12.7 On-going precision and accuracy.


12.7.1 Analyze the extract of one of the pair of precision and recovery standards (Section 10.1.3) prior to analysis of samples from the same lot.


12.7.2 Compute the concentration of each pollutant (Tables 1 and 2) by isotope dilution (Section 7.4) for those compounds which have labeled analogs. Compute the concentration of each pollutant which has no labeled analog by the internal standard method (Section 7.5). Compute the concentration of the labeled compounds by the internal standard method.


12.7.3 For each pollutant and labeled compound, compare the concentration with the limits for on-going accuracy in Table 8. If all compounds meet the acceptance criteria, system performance is acceptable and analysis of blanks and samples may proceed. If, however, any individual concentration falls outside of the range given, system performance is unacceptable for that compound.



Note:

The large number of compounds in Table 8 present a substantial probability that one or more will fail when all compounds are analyzed. To determine if the extraction/concentration system is out of control or if the failure is caused by probability, proceed as follows:


12.7.3.1 Analyze the second aliquot of the pair of precision and recovery standard (Section 10.1.3).


12.7.3.2 Compute the concentration of only those pollutants or labeled compounds that failed the previous test (Section 12.7.3). If these compounds now pass, the extraction/concentration processes are in control and analysis of blanks and samples may proceed. If, however, any of the same compounds fail again, the extraction/concentration processes are not being performed properly for these compounds. In this event, correct the problem, re-extract the sample lot (Section 10) and repeat the on-going precision and recovery test (Section 12.7).


12.7.4 Add results which pass the specifications in Section 12.7.2 to initial and previous on-going data. Update QC charts to perform a graphic representation of continued laboratory performance (Figure 5). Develop a statement of laboratory accuracy for each pollutant and labeled compound by calculating the average percent recovery (R) and the standard deviation of percent recovery (sr). Express the accuracy as a recovery interval from R−2sr to R + 2sr. For example, if R = 95% and sr = 5%, the accuracy is 85−105%.


13. Qualitative Determination

13.1 Qualititative determination is accomplished by comparison of data from analysis of a sample or blank with data from analysis of the shift standard (Section 12.1) and with data stored in the spectral libraries (Section 7.2.4). Identification is confirmed when spectra and retention times agree per the criteria below.


13.2 Labeled compounds and pollutants having no labeled analog:


13.2.1 The signals for all characteristic masses stored in the spectral library (Section 7.2.4) shall be present and shall maximize within the same two consecutive scans.


13.2.2 Either (1) the background corrected EICP areas, or (2) the corrected relative intensities of the mass spectral peaks at the GC peak maximum shall agree within a factor of two (0.5 to 2 times) for all masses stored in the library.


13.2.3 The retention time relative to the nearest eluted internal standard shall be within ±15 scans or ±15 seconds, whichever is greater of this difference in the shift standard (Section 12.1).


13.3 Pollutants having a labled analog:


13.3.1 The signals for all characteristic masses stored in the spectral library (Section 7.2.4) shall be present and shall maximize within the same two consecutive scans.


13.3.2. Either (1) the background corrected EICP areas, or (2) the corrected relative intensities of the mass spectral peaks at the GC peak maximum shall agree within a factor of two for all masses stored in the spectral library.


13.3.3. The retention time difference between the pollutant and its labeled analog shall agree within ±6 scans or ±6 seconds (whichever is greater) of this difference in the shift standard (Section 12.1).


13.4 Masses present in the experimental mass spectrum that are not present in the reference mass spectrum shall be accounted for by contaminant or background ions. If the experimental mass spectrum is contaminated, an experienced spectrometrist (Section 1.4) is to determine the presence or absence of the cmmpound.


14. Quantitative Determination

14.1 Isotope dilution—by adding a known amount of a labeled compound to every sample prior to extraction, correction for recovery of the pollutant can be made because the pollutant and its labeled analog exhibit the same effects upon extraction, concentration, and gas chromatography. Relative response (RR) values for mixtures are used in conjunction with calibration curves described in Section 7.4 to determine concentrations directly, so long as labeled compound spiking levels are constant. For the phenml example given in Figure 1 (Section 7.4.1), RR would be equal to 1.114. For this RR value, the phenol calibration curve given in Figure 1 indicates a concentration of 27 µg/mL in the sample extract (Cex).


14.2 Internal standard—compute the concentration in the extract using the response factor determined from calibration data (Section 7.5) and the following equation: Cex(µg/mL) = (As × Cis/(Ais × RF) where Cex is the concentration of the compound in the extract, and the other terms are as defined in Section 7.5.1.


14.3 The concentration of the pollutant in water is computed using the volumes of the original water sample (Section 10.1) and the final extract volume (Section 10.5), as follows: Concentration in water (µg/L) = (Cex × Vex)/Vs where Vex is the extract volume in mL, and Vs is the sample volume in liters.


14.4 If the EICP area at the quantitiation mass for any compound exceeds the calibration range of the system, the extract of the dilute aliquot (Section 10.1) is analyzed by isotope dilution; otherwise, the extract is diluted by a factor of 10, 9 µL of internal standard solution (Section 6.10) are added to a 1.0 mL aliquot, and this diluted extract is analyzed by the internal standard method (Section 14.2). Quantify each compound at the highest concentration level within the calibration range.


14.5 Report results for all pollutants and labeled compounds (Tables 1 and 2) found in all standards, blanks, and samples in µg/L, to three significant figures. Results for samples which have been diluted are reported at the least dilute level at which the area at the quantitation mass is within the calibration range (Section 14.4) and the labeled compound recovery is within the normal range for the method (Section 15.4).


15. Analysis of Complex Samples

15.1 Untreated effluents and other samples frequently contain high levels (>1000 µg/L) of the compounds of interest, interfering compounds, and/or polymeric materials. Some samples will not concentrate to one mL (Section 10.5); others will overload the GC column and/or mass spectrometer.


15.2 Analyze the dilute aliquot (Section 10.1) when the sample will not concentrate to 1.0 mL. If a dilute aliquot was not extracted, and the sample holding time (Section 9.3) has not been exceeded, dilute an aliquot of the sample with reagent water and re-extract (Section 10.1); otherwise, dilute the extract (Section 14.4) and analyze by the internal standard method (Section 14.2).


15.3 Recovery of internal standard—the EICP area of the internal standard should be within a factor of two of the area in the shift standard (Section 12.1). If the absolute areas of the labeled compounds are within a factor of two of the respective areas in the shift standard, and the internal standard area is less than one-half of its respective area, then internal standard loss in the extract has occurred. In this case, use one of the labeled compounds (perferably a polynuclear aromatic hydrocarbon) to compute the concentration of a pollutant with no labeled analog.


15.4 Recovery of labeled compounds—in most samples, labeled compound recoveries will be similar to those from reagent water (Section 12.7). If the labeled compound recovery is outside the limits given in Table 8, the dilute extract (Section 10.1) is analyzed as in Section 14.4. If the recoveries of all labeled compounds and the internal staldard are low (per the criteria above), then a loss in instrument sensitivity is the most likely cause. In this case, the 100 µg/mL calibration standard (Section 12.1) shall be analyzed and calibration verified (Section 12.5). If a loss in sensitivity has occurred, the instrument shall be repaired, the performance specifications in Section 12 shall be met, and the extract reanalyzed. If a loss in instrument sensitivity has not occurred, the method does not work on the sample being analyzed and the result may not be reported for regulatory compliance purposes.


16. Method Performance

16.1 Interlaboratory performance for this method is detailed in references 9 and 10.


16.2 A chromatogram of the 100 µg/mL acid/base/neutral calibration standard (Section 6.13) is shown in Figure 6.


References

1. “Performance Tests for the Evaluation of Computerized Gas Chromatography/Mass Spectrometry Equipment and Laboratories” USEPA, EMSL/Cincinnati, OH 45268, EPA-600/4-80-025 (April 1980).


2. “Working with Carcinogens,” DHEW, PHS, CDC, NIOSH, Publication 77-206, (August 1977).


3. “OSHA Safety and Health Standards, General Industry” OSHA 2206, 29 CFR part 1910 (January 1976).


4. “Safety in Academic Chemistry Laboratories, ” ACS Committee on Chemical Safety (1979).


5. “Reference Compound to Calibrate Ion Abundance Measurement in Gas Chromatography-Mass Spectrometry Systems,” J.W. Eichelberger, L.E. Harris, and W.L. Budde, Anal. Chem., 47, 955 (1975).


6. “Handbook of Analytical Quality Control in Water and Wastewater Laboratories,” USEPA, EMSL/Cincinnati, OH 45268, EPA-600/4-79-019 (March 1979).


7. “Standard Practice for Sampling Water,” ASTM Annual Book of Standards, ASTM, Philadelphia, PA, 76 (1980).


8. “Methods 330.4 and 330.5 for Total Residual Chlorine,” USEPA, EMSL/ Cincinnati, OH 45268, EPA 600/4-70-020 (March 1979).


9. Colby, B.N., Beimer, R.G., Rushneck, D.R., and Telliard, W.A., “Isotope Dilution Gas Chromatography-Mass Spectrometry for the determination of Priority Pollutants in Industrial Effluents.” USEPA, Effluent Guidelines Division, Washington, DC 20460 (1980).


10. “Inter-laboratory Validation of US Environmental Protection Agency Method 1625,” USEPA, Effluent Guidelines Division, Washington, DC 20460 (June 15, 1984).


Table 1—Base/Neutral Extractable Compounds

Compound
STORET
CAS registry
EPA-EGD
NPDES
Acenaphthene3420583-32-9001 B001 B
Acenaphthylene34200208-96-8077 B002 B
Anthracene34220120-12-7078 B003 B
Benzidine3912092-87-5005 B004 B
Benzo(a)anthracene3452656-55-3072 B005 B
Benzo(b)fluoranthene34230205-99-2074 B007 B
Benzo(k)fluoranthene34242207-08-9075 B009 B
Benzo(a)pyrene3424750-32-8073 B006 B
Benzo(ghi)perylene34521191-24-2079 B008 B
Biphenyl (Appendix C)8151392-52-4512 B
Bis(2-chloroethyl) ether34273111-44-4018 B011 B
Bis(2-chloroethyoxy)methane34278111-91-1043 B010 B
Bis(2-chloroisopropyl) ether34283108-60-1042 B012 B
Bis(2-ethylhexyl) phthalate39100117-81-7066 B013 B
4-bromophenyl phenyl ether34636101-55-3041 B014 B
Butyl benzyl phthalate3429285-68-7067 B015 B
n-C10 (Appendix C)77427124-18-5517 B
n-C12 (Appendix C)77588112-40-2506 B
n-C14 (Appendix C)77691629-59-4518 B
n-C16 (Appendix C)77757544-76-3519 B
n-C18 (Appendix C)77804593-45-3520 B
n-C20 (Appendix C)77830112-95-8521 B
n-C22 (Appendix C)77859629-97-0522 B
n-C24 (Appendix C)77886646-31-1523 B
n-C26 (Appendix C)77901630-01-3524 B
n-C28 (Appendix C)78116630-02-4525 B
n-C30 (Appendix C)78117638-68-6526 B
Carbazole (4c)7757186-74-8528 B
2-chloronaphthalene3458191-58-7020 B016 B
4-chlorophenyl phenyl ether346417005-72-3040 B017 B
Chrysene34320218-01-9076 B018 B
P-cymene (Appendix C)7735699-87-6513 B
Dibenzo(a,h)anthracene3455653-70-3082 B019 B
Dibenzofuran (Appendix C and 4c)81302132-64-9505 B
Dibenzothiophene (Synfuel)77639132-65-0504 B
Di-n-butyl phthalate3911084-74-2068 B026 B
1,2-dichlorobenzene3453695-50-1025 B020 B
1,3-dichlorobenzene34566541-73-1026 B021 B
1,4-dichlorobenzene34571106-46-7027 B022 B
3,3′-dichlorobenzidine3463191-94-1028 B023 B
Diethyl phthalate3433684-66-2070 B024 B
2,4-dimethylphenol34606105-67-9034 A003 A
Dimethyl phthalate34341131-11-3071 B025 B
2,4-dinitrotoluene34611121-14-2035 B027 B
2,6-dinitrotoluene34626606-20-2036 B028 B
Di-n-octyl phthalate34596117-84-0069 B029 B
Diphenylamine (Appendix C)77579122-39-4507 B
Diphenyl ether (Appendix C)77587101-84-8508 B
1,2-diphenylhydrazine34346122-66-7037 B030 B
Fluoranthene34376206-44-0039 B031 B
Fluorene3438186-73-7080 B032 B
Hexachlorobenzene39700118-74-1009 B033 B
Hexachlorobutadiene3439187-68-3052 B034 B
Hexachloroethane3439667-72-1012 B036 B
Hexachlorocyclopentadiene3438677-47-4053 B035 B
Indeno(1,2,3-cd)pyrene34403193-39-5083 B037 B
Isophorone3440878-59-1054 B038 B
Naphthalene3469691-20-3055 B039 B
B-naphthylamine (Appendix C)8255391-59-8502 B
Nitrobenzene3444798-95-3056 B040 B
N-nitrosodimethylamine3443862-75-9061 B041 B
N-nitrosodi-n-propylamine34428621-64-7063 B042 B
N-nitrosodiphenylamine3443386-30-3062 B043 B
Phenanthrene3446185-01-8081 B044 B
Phenol34694108-95-2065 A010 A
a-Picoline (Synfuel)77088109-06-89503 B
Pyrene34469129-00-0084 B045 B
styrene (Appendix C)77128100-42-5510 B
a-terpineol (Appendix C)7749398-55-5509 B
1,2,3-trichlorobenzene (4c)7761387-61-6529 B
1,2,4-trichlorobenzene34551120-82-1008 B046 B

Table 2—Acid Extractable Compounds

Compound
STORET
CAS registry
EPA-EGD
NPDES
4-chloro-3-methylphenol3445259-50-7022 A008 A
2-chlorophenol3458695-57-8024 A001 A
2,4-dichlorophenol34601120-83-2031 A002 A
2,4-dinitrophenol3461651-28-5059 A005 A
2-methyl-4,6-dinitrophenol34657534-52-1060 A004 A
2-nitrophenol3459188-75-5057 A006 A
4-nitrophenol34646100-02-7058 A007 A
Pentachlorophenol3903287-86-5064 A009 A
2,3,6-trichlorophenol (4c)7768893-37-55530 A
2,4,5-trichlorophenol (4c)95-95-4531 A
2,4,6-trichlorophenol3462188-06-2021 A011 A

Table 3—Gas Chromatography of Base/Neutral Extractable Compounds

EGD No.
1
Compound
Retention time
Detection limit
2 (µg/L)
Mean (sec)
EGD Ref
Relative
1642,2′-difluorobiphenyl (int std)11631641.000-1.00010
061N-nitrosodimethylamine385164ns50
603alpha picoline-d74171640.326-0.39350
703alpha picoline4266031.006-1.02850
610styrene-d55461640.450-0.48810
710styrene5496101.002-1.00910
613p-cymene-d147421640.624-0.65210
713p-cymene7556131.008-1.02310
265phenol-d56961640.584-0.61310
365phenol7002650.995-1.01010
218bis(2-chloroethyl) ether-d86961640.584-0.60710
318bis(2-chloroethyl) ether7042181.007-1.01610
617n-decane-d226981640.585-0.61510
717n-decane7206171.022-1.03810
2261,3-dichlorobenzene-d47221640.605-0.63610
3261,3-dichlorobenzene7242260.998-1.00810
2271,4-dichlorobenzene-d47371640.601-0.66610
3271,4-dichlorobenzene7402270.997-1.00910
2251,2-dichlorobenzene-d47581640.632-0.66710
3251,2-dichlorobenzene7602250.995-1.00810
242bis(2-chloroisopropyl) ether-d127881640.664-0.69110
342bis(2-chloroisopropyl) ether7992421.010-1.01610
212hexachloroethane-13C8191640.690-0.71710
312hexachloroethane8232120.999-1.00110
063N-nitrosodi-n-propylamine830164ns20
256nitrobenzene-d58451640.706-0.72710
356nitrobenzene8492561.002-1.00710
254isophorone-d88811640.747-0.76710
354isophorone8892540.999-1.01710
2342,4-dimethyl phenol-d39211640.781-0.80310
3342,4-dimethylphenol9242340.999-1.00310
043bis(2-chloroethoxy) methane939164ns10
2081,2,4-trichlorobenzene-d39551640.813-0.83010
3081,2,4-trichlorobenzene9582081.000-1.00510
255naphthalene-d89631640.819-0.83610
355naphthalene9672551.001-1.00610
609alpha-terpineol-d39731640.829-0.84410
709alpha-terpineol9756090.998-1.00810
606n-dodecane-d269531640.730-0.90810
706n-dodecane9816060.986-1.05110
5291,2,3-trichlorobenzene1003164ns10
252hexachlorobutadiene-13C410051640.856-0.87110
352hexachlorobutadiene10062520.999-1.00210
253hexachlorocyclopentadiene-13C411471640.976-0.98610
353hexachlorocyclopentadiene11422530.999-1.00110
2202-chloronaphthalene-d711851641.014-1.02410
3202-chloronaphthalene12002200.997-1.00710
518n-tetradecane1203164ns10
612Biphenyl-d1012051641.016-1.02710
712Biphenyl11956121.001-1.00610
608Diphenyl ether-d1012111641.036-1.04710
708Diphenyl ether12166080.997-1.00910
277Acenaphthylene-d812651641.080-1.09510
377Acenaphthylene12472771.000-1.00410
271Dimethyl phthalate-d412691641.083-1.10210
371Dimethyl phthalate12732710.998-1.00510
2362,6-dinitrotoluene-d312831641.090-1.11210
3362,6-dinitrotoluene13002361.001-1.00510
201Acenaphthene-d1012981641.107-1.12510
301Acenaphthene13042010.999-1.00910
605Dibenzofuran-d813311641.134-1.15510
705Dibenzofuran13356050.998-1.00710
602Beta-naphthylamine-d713681641.163-1.18950
702Beta-naphthylamine13716020.996-1.00750
280Fluorene-d1013951641.185-1.21410
380Fluorene14012810.999-1.00810
2404-chlorophenyl phenyl ether-d514061641.194-1.22310
3404-chlorophenyl phenyl ether14092400.990-1.01510
270Diethyl phthalate-d414091641.197-1.22910
370Diethyl phthalate14142700.996-1.00610
619n-hexadecane-d3414471641.010-1.47810
719n-hexadecane14696191.013-1.02010
2352,4-dinitrotoluene-d313591641.152-1.18110
3352,4-dinitrotoluene13442351.000-1.00210
2371,2-diphenylhydrazine-d814331641.216-1.24820
3371,2-diphenylhydrazine (
3)		14392370.999-1.00920
607Diphenylamine-d1014371641.213-1.24920
707Diphenylamine14396071.000-1.00720
262N-nitrosodiphenylamine-d614471641.225-1.25220
362N-nitrosodiphenylamine (
4)		14642621.000-1.00220
0414-bromophenyl phenyl ether14981641.271-1.30710
209Hexachlorobenzene-13C615211641.288-1.32710
309Hexachlorobenzene15222090.999-1.00110
281Phenanthrene-d1015781641.334-1.38010
520n-octadecane1580164ns10
381Phenanthrene15832811.000-1.00510
278Anthracene-d1015881641.342-1.38810
378Anthracene15922780.998-1.00610
604Dibenzothiophene-d815591641.314-1.36110
704Dibenzothiophene15646041.000-1.00610
528Carbazole1650164ns20
621n-eicosane-d4216551641.184-1.66210
721n-eicosane16776211.010-1.02110
268Di-n-butyl phthalate-d417191641.446-1.51010
368Di-n-butyl phthalate17232681.000-1.00310
239Fluoranthene-d1018131641.522-1.59610
339Fluoranthene18172391.000-1.00410
284Pyrene-d1018441641.523-1.64410
384Pyrene18522841.001-1.00310
205Benzidine-d818541641.549-1.63250
305Benzidine18532051.000-1.00250
522n-docosane1889164ns10
623n-tetracosane-d5019971641.671-1.76410
723n-tetracosane20256121.012-1.01510
067Butylbenzyl phthalate2060164ns10
276Chrysene-d1220811641.743-1.83710
376Chrysene20832761.000-1.00410
272Benzo(a)anthracene-d1220821641.735-1.84610
372Benzo(a)anthracene20902720.999-1.00710
2283,3′-dichlorobenzidine-d620881641.744-1.84850
3283,3′-dichlorobenzidine20862281.000-1.00150
266Bis(2-ethylhexyl) phthalate-d421231641.771-1.88010
366Bis(2-ethylhexyl) phthalate21242661.000-1.00210
524n-hexacosane2147164ns10
269di-n-octyl phthalate-d422391641.867-1.98210
369di-n-octyl phthalate22402691.000-1.00210
525n-octacosane2272164ns10
274Benzo(b)fluoranthene-d1222811641.902-2.02510
354Benzo(b)fluoranthene22932741.000-1.00510
275Benzo(k)fluoranthene-d1222871641.906-2.03310
375Benzo(k)fluoranthene22932751.000-1.00510
273Benzo(a)pyrene-d1223511641.954-2.08810
373Benzo(a)pyrene23502731.000-1.00410
626N-triacontane-d6223841641.972-2.12710
726N-triacontane24296261.011-1.02810
083Indeno(1,2,3-cd)pyrene2650164ns20
082Dibenzo(a,h)anthracene2660164ns20
279Benzo(ghi)perylene-d1227411642.187-2.52420
379Benzo(ghi)perylene27502791.001-1.00620


1 Reference numbers beginning with 0, 1 or 5 indicate a pollutant quantified by the internal standard method; reference numbers beginning with 2 or 6 indicate a labeled compound quantified by the internal standard method; reference numbers beginning with 3 or 7 indicate a pollutant quantified by isotope dilution.


2 This is a minimum level at which the entire GC/MS system must give recognizable mass spectra (background corrected) and acceptable calibration points.


3 Detected as azobenzene.


4 Detected as diphenylamine.

ns = specification not available at time of release of method.

Column: 30 ±2 m × 0.25 ±0.02 mm i.d. 94% methyl, 4% phenyl, 1% vinyl bonded phase fused silica capillary.

Temperature program: 5 min at 30 °C; 30 – 280 °C at 8 °C per min; isothermal at 280 °C until benzo(ghi)perylene elutes.

Gas velocity: 30 ±5 cm/sec.


Table 4—Gas Chromatography of Acid Extractable Compounds

EGD No.
1
Compound
Retention time
Detection limit
2 (µg/L)
Mean (sec)
EGD Ref
Relative
1642,2′-difluorobiphenyl (int std)11631641.000-1.00010
2242-chlorophenol-d47011640.587-0.61810
3242-chlorophenol7052240.997-1.01010
2572-nitrophenol-d48981640.761-0.78320
3572-nitrophenol9002570.994-1.00920
2312,4-dichlorophenol-d39441640.802-0.82210
3312,4-dichlorophenol9472310.997-1.00610
2224-chloro-3-methylphenol-d210861640.930-0.94310
3224-chloro-3-methylphenol10912220.998-1.00310
2212,4,6-trichlorophenol-d211621640.994-1.00510
3212,4,6-trichlorophenol11652210.998-1.00410
5312,4,5-trichlorophenol1170164ns10
5302,3,6-trichlorophenol1195164ns10
2592,4-dinitrophenol-d313231641.127-1.14950
3592,4-dinitrophenol13252591.000-1.00550
2584-nitrophenol-d413491641.147-1.17550
3584-nitrophenol13542580.997-1.00650
2602-methyl-4,6-dinitrophenol-d214331641.216-1.24920
3602-methyl-4,6-dinitrophenol14352601.000-1.00220
264Pentachlorophenol-13C615591641.320-1.36350
364Pentachlorophenol15612640.998-1.00250


1 Reference numbers beginning with 0, 1 or 5 indicate a pollutant quantified by the internal standard method; reference numbers beginning with 2 or 6 indicate a labeled compound quantified by the internal standard method; reference numbers beginning with 3 or 7 indicate a pollutant quantified by isotope dilution.


2 This is a minimum level at which the entire GC/MS system must give recognizable mass spectra (background corrected) and acceptable calibration points.

ns = specification not available at time of release of method.

Column: 30 ±2m × 0.25 ±0.02mm i.d. 94% methyl, 4% phenyl, 1% vinyl bonded phase fused silica capillary.

Temperature program: 5 min at 30 °C; 8 °C/min. to 250 °C or until pentachlorophenol elutes.

Gas velocity: 30 ±5 cm/sec.


Table 5—DFTPP Mass Intensity Specifications

Mass
Intensity required
5130-60 percent of mass 198.
68Less than 2 percent of mass 69.
70Less than 2 percent of mass 69.
12740-60 percent of mass 198.
197Less than 1 percent of mass 198.
1995-9 percent of mass 198.
27510-30 percent of mass 198.
365greater than 1 percent of mass 198
441present and less than mass 443
44240-100 percent of mass 198.
44317-23 percent of mass 442.

Table 6—Base/Neutral Extractable Compound Characteristic Masses

Compound
Labeled analog
Primary m/z
Acenaphthened10154/164
Acenaphthylened8152/160
Anthracened10178/188
Benzidined8184/192
Benzo(a)anthracened12228/240
Benzo(b)fluoranthened12252/264
Benzo(k)fluoranthened12252/264
Benzo(a)pyrened12252/264
Benzo(ghi)perylened12276/288
Biphenyld10154/164
Bis(2-chloroethyl) etherd893/101
Bis(2-chloroethoxy)methane93
Bis(2-chloroisopropyl) etherd12121/131
Bis(2-ethylhexyl) phthalated4149/153
4-bromophenyl phenyl ether248
Butyl benzyl phthalate149
n-C10d2255/66
n-C12d2655/66
n-C1455
n-C16d3455/66
n-C1855
n-C20d4255/66
n-C2255
n-C24d5055/66
n-C2655
n-C2855
n-C30d6255/66
Carbazoled8167/175
2-chloronaphthalened7162/169
4-chlorophenyl phenyl etherd5204/209
Chrysened12228/240
p-cymened14114/130
Dibenzo(a,h)anthracene278
Dibenzofurand8168/176
Dibenzothiophened8184/192
Di-n-butyl phthalated4149/153
1,2-dichlorobenzened4146/152
1,3-dichlorobenzened4146/152
1,4-dichlorobenzened4146/152
3,3′-dichlorobenzidined6252/258
Diethyl phthalated4149/153
2,4-dimethylphenold3122/125
Dimethyl phthalated4163/167
2,4-dinitrotoluened3164/168
2,6-dinitrotoluened3165/167
Di-n-octyl phthalated4149/153
Diphenylamined10169/179
Diphenyl etherd10170/180
1,2-diphenylhydrazine
1		d1077/82
Fluoranthened10202/212
Fluorened10166/176
Hexachlorobenzene13C6284/292
Hexachlorobutadiene13C4225/231
Hexachloroethane13C201/204
Hexachlorocyclopentadiene13C4237/241
Ideno(1,2,3-cd)pyrene276
Isophoroned882/88
Naphthalened8128/136
B-naphthylamined7143/150
Nitrobenzened5123/128
N-nitrosodimethylamine74
N-nitrosodi-n-propylamine70
N-nitrosodiphenylamile
2		d6169/175
Phenanthrened10178/188
Phenold594/71
a-picolined793/100
Pyrened10202/212
Styrened5104/109
a-terpineold359/62
1,2,3-trichlorobenzened3180/183
1,2,4-trichlorobenzened3180/183


1 Detected as azobenzene.


2 Detected as diphenylamine.


Table 7—Acid Extractable Compound Characteristic Masses

Compound
Labeled analog
Primary m/z
4-chloro-3-methylphenold2107/109
2-chlorophenold4128/132
2,4-dichlorophenold3162/167
2,4-dinitrophenold3184/187
2-methyl-4,6-dinitrophenold2198/200
2-nitrophenold4139/143
4-nitrophenold4139/143
Pentachlorophenol13C6266/272
2,3,6-trichlorophenold2196/200
2,4,5-trichlorophenold2196/200
2,4,6-trichlorophenold2196/200

Table 8—Acceptance Criteria for Performance Tests

EGD No.
1
Compound
Acceptance criteria
Initial precision and accuracy section 8.2.3 (µg/L)
Labeled compound recovery sec. 8.3 and 14.2 P (percent)
Calibration verification sec. 12.5 (µg/mL)
On-going accuracy sec. 11.6 R (µg/L)
s
X
301Acenaphthene2179-13480-12572-144
201Acenaphthene-d103838-14720-27071-14130-180
377Acenaphtylene3869-18660-16661-207
277Acenaphthylene-d83138-14623-23966-15233-168
378Anthracene4158-17460-16850-199
278Anthracene-d104931-19414-41958-17123-242
305Benzidine11916-51834-29611-672
205Benzidine-d8269ns-nsns-nsns-nsns-ns
372Benzo(a)anthracene2065-16870-14262-176
272Benzo(a)anthracene-d124125-29812-60528-35722-329
374Benzo(b)fluoranthene18332-54561-16420-ns
274Benzo(b)fluoranthene-d1216811-577ns-ns14-nsns-ns
375Benzo(k)fluoranthene2659-14313-ns53-155
275Benzo(k)fluoranthene-d1211415-514ns-ns13-nsns-685
373Benzo(a)pyrene2662-19578-12959-206
273Benzo(a)pyrene-d122435-18121-29012-ns32-194
379Benzo(ghi)perylene2172-16069-14558-168
279Benzo(ghi)perylene-d124529-26814-52913-ns25-303
712Biphenyl (Appendix C)4175-14858-17162-176
612Biphenyl-d124328-165ns-ns52-19217-267
318Bis(2-chloroethyl) ether3455-19661-16450-213
218Bis(2-chloroethyl) ether-d83329-19615-37252-19425-222
043Bis(2-chloroethoxy)methane*2743-15344-22839-166
342Bis(2-chloroisopropyl) ether1781-13867-14877-145
242Bis(2-chloroisopropyl)ether-d122735-14920-26044-22930-169
366Bis(2-ethylhexyl) phthalate3169-22076-13164-232
266Bis(2-ethylhexyl) phthalate-d42932-20518-36443-23228-224
0414-bromophenyl phenyl ether*4444-14052-19335-172
067Butyl benzyl phthalate*3119-23322-45035-170
717n-C10 (Appendix C)5124-19542-23519-237
617n-C10-d2270ns-298ns-ns44-227ns-504
706n-C12 (Appendix C)7435-36960-16629-424
606n-C12-d2653ns-331ns-ns41-242ns-408
518n-C14 (Appendix C)*109ns-98537-268ns-ns
719n-C16 (Appendix C)3380-16272-13871-181
619n-C16-d344637-16218-30854-18628-202
520n-C18 (Appendix C)*3942-13140-24935-167
721n-C20 (Appendix C)5953-26354-18446-301
621n-C20-d423434-17219-30662-16229-198
522n-C22 (Appendix C)*3145-15240-24939-195
723n-C24 (Appendix C)1180-13965-15478-142
623n-C24-d502827-21115-37650-19925-229
524n-C26 (Appendix C)*3535-19326-39231-212
525n-C28 (Appendix C)*3535-19326-39231-212
726n-C30 (Appendix C)3261-20066-15256-215
626n-C30-d624127-24213-47924-42323-274
528Carbazole (4c)*3836-16544-22731-188
3202-chloronaphthalene10046-35758-17135-442
2202-chloronaphthalene-d74130-16815-32472-13924-204
3224-chloro-3-methylphenol3776-13185-11562-159
2224-chloro-3-methylphenol-d211130-174ns-61368-14714-314
3242-chlorophenol1379-13578-12976-138
2242-chlorophenol-d42436-16223-25555-18033-176
3404-chlorophenyl phenyl ether4275-16671-14263-194
2404-chlorophenyl phenyl ether-d55240-16119-32557-17529-212
376Chrysene5159-18670-14248-221
276Chrysene-d126933-21913-51224-41123-290
713p-cymene (Appendix C)1876-14079-12772-147
613p-cymene-d1467ns-359ns-ns66-152ns-468
082Dibenzo(a,h)anthracene*5523-29913-76119-340
705Dibenzofuran (Appendix C)2085-13673-13679-146
605Dibenzofuran-d83147-13628-22066-15039-160
704Dibenzothiophene (Synfuel)3179-15072-14070-168
604Dibenzothiophene-d83148-13029-21569-14540-156
368Di-n-butyl phthalate1576-16571-14274-169
268Di-n-butyl phthalate-d42323-19513-34652-19222-209
3251,2-dichlorobenzene1773-14674-13570-152
2251,2-dichlorobenzene-d43514-212ns-49461-16411-247
3261,3-dichlorobenzene4363-20165-15455-225
2261,3-dichlorobenzene-d44813-203ns-55052-192ns-260
3271,4-dichlorobenzene4261-19462-16153-219
2271,4-dichlorobenzene-d44815-193ns-47465-15311-245
3283,3′-dichlorobenzidine2668-17477-13064-185
2283,3′-dichlorobenzidine-d680ns-562ns-ns18-558ns-ns
3312,4-dichlorophenol1285-13167-14983-135
2312,4-dichlorophenol-d32838-16424-26064-15734-182
370Diethyl phthalate4475-19674-13565-222
270Diethyl phthalate-d478ns-260ns-ns47-211ns-ns
3342,4-dimethylphenol1362-15367-15060-156
2342,4-dimethylphenol-d32215-228ns-44958-17214-242
371Dimethyl phthalate3674-18873-13767-207
271Dimethyl phthalate-d4108ns-640ns-ns50-201ns-ns
3592,4-dinitrophenol1872-13475-13368-141
2592,4-dinitrophenol-d36622-308ns-ns39-25617-378
3352,4-dinitrotoluene1875-15879-12772-164
2352,4-dinitrotoluene-d33722-24510-51453-18719-275
3362,6-dinitrotoluene3080-14155-18370-159
2362,6-dinitrotoluene-d35944-18417-44236-27831-250
369Di-n-octyl phthalate1677-16171-14074-166
269Di-n-octyl phthalate-d44612-383ns-ns21-46710-433
707Diphenylamine (Appendix C)4558-20557-17651-231
607Diphenylamine-d104227-20611-48859-16921-249
708Diphenyl ether (Appendix C)1982-13683-12077-144
608Diphenyl ether-d103736-15519-28177-12929-186
3371,2-diphenylhydrazine7349-30875-13440-360
2371,2-diphenylhydrazine-d103531-17317-31658-17426-200
339Fluoranthene3371-17767-14964-194
239Fluoranthene-d103536-16120-27847-21530-187
380Fluorene2981-13274-13570-151
280Fluorene-d104351-13127-23861-16438-172
309Hexachlorobenzene1690-12478-12885-132
209Hexachlorobenzene-13C68136-22813-59538-26523-321
352hexachlorobutadiene5651-25174-13543-287
252hexachlorobutadiene-13C463ns-316ns-ns68-148ns-413
312hexachloroethane22721-ns71-14113-ns
212hexachloroethane-13C177ns-400ns-ns47-212ns-563
353hexachlorocyclopentadiene1569-14477-12967-148
253hexachlorocyclopentadiene-13C460ns-nsns-ns47-211ns-ns
083ideno(1,2,3-cd)pyrene*5523-29913-76119-340
354isophorone2576-15670-14270-168
254isophorone-d82349-13333-19352-19444-147
3602-methyl-4,6-dinitrophenol1977-13369-14572-142
2602-methyl-4,6-dinitrophenol-d26436-24716-52756-17728-307
355naphthalene2080-13973-13775-149
255naphthalene-d83928-15714-30571-14122-192
702B-naphthylamine (Appendix C)4910-ns39-256ns-ns
602B-naphthylamine-d733ns-nsns-ns44-230ns-ns
356nitrobenzene2569-16185-11565-169
256nitrobenzene-d52818-265ns-ns46-21915-314
3572-nitrophenol1578-14077-12975-145
2572-nitrophenol-d42341-14527-21761-16337-158
3584-nitrophenol4262-14655-18351-175
2584-nitrophenol-d418814-398ns-ns35-287ns-ns
061N-nitrosodimethylamile*19821-47240-24912-807
063N-nitrosodi-n-proplyamine*19821-47240-24912-807
362N-nitrosodiphenylamine4565-14268-14853-173
262N-nitrosodiphenylamine-d63754-12626-25659-17040-166
364pentachlorophenol2176-14077-13071-150
264pentachlorophenol-13C64937-21218-41242-23729-254
381phenanthrene1393-11975-13387-126
281phenanthrene-d104045-13024-24167-14934-168
365phenol3677-12765-15562-154
265phenol-d516121-210ns-ns48-208ns-ns
703a-picoline (Synfuel)3859-14960-16550-174
603a-picoline-d713811-380ns-ns31-324ns-608
384pyrene1976-15276-13272-159
284pyrene-d102932-17618-30348-21028-196
710styrene (Appendix C)4253-22165-15348-244
610styrene-d549ns-281ns-ns44-228ns-348
709a-terpineol (Appendix C)4442-23454-18638-258
609a-terpineol-d34822-292ns-67220-50218-339
5291,2,3-trichlorobenzene (4c)*6915-22960-16711-297
3081,2,4-trichlorobenzene1982-13678-12877-144
2081,2,4-trichlorobenzene-d35715-212ns-59261-16310-282
5302,3,6-trichlorophenol (4c)*3058-13756-18051-153
5312,4,5-trichlorophenol (4c)*3058-13756-18051-153
3212,4,6-trichlorophenol5759-20581-12348-244
2212,4,6-trichlorophenol-d24743-18321-36369-14434-226


1 Reference numbers beginning with 0, 1 or 5 indicate a pollutant quantified by the internal standard method; reference numbers beginning with 2 or 6 indicate a labeled compound quantified by the internal standard method; reference numbers beginning with 3 or 7 indicate a pollutant quantified by isotope dilution.

* Measured by internal standard; specification derived from related compound.

ns = no specification; limit is outside the range that can be measured reliably.





Attachment 1 to Method 1625

Introduction

To support measurement of several semivolatile pollutants, EPA has developed this attachment to EPA Method 1625B.
1
The modifications listed in this attachment are approved only for monitoring wastestreams from the Centralized Waste Treatment Point Source Category (40 CFR part 437) and the Landfills Point Source Category (40 CFR part 445). EPA Method 1625B (the Method) employs sample extraction with methylene chloride followed by analysis of the extract using capillary column gas chromatography-mass spectrometry (GC/MS). This attachment addresses the addition of the semivolatile pollutants listed in Tables 1 and 2 to all applicable standard, stock, and spiking solutions utilized for the determination of semivolatile organic compounds by EPA Method 1625B.




1 EPA Method 1625 Revision B, Semivolatile Organic Compounds by Isotope Dilution GC/MS, 40 CFR part 136, appendix A.


1.0 EPA METHOD 1625 REVISION B MODIFICATION SUMMARY

The additional semivolatile organic compounds listed in Tables 1 and 2 are added to all applicable calibration, spiking, and other solutions utilized in the determination of semivolatile compounds by EPA Method 1625. The instrument is to be calibrated with these compounds, and all procedures and quality control tests described in the Method must be performed.


2.0 SECTION MODIFICATIONS


Note:

All section and figure numbers in this Attachment reference section and figure numbers in EPA Method 1625 Revision B unless noted otherwise. Sections not listed here remain unchanged.


Section 6.7 The stock standard solutions described in this section are modified such that the analytes in Tables 1 and 2 of this attachment are required in addition to those specified in the Method.

Section 6.8 The labeled compound spiking solution in this section is modified to include the labeled compounds listed in Tables 5 and 6 of this attachment.

Section 6.9 The secondary standard is modified to include the additional analytes listed in Tables 1 and 2 of this attachment.

Section 6.12 The solutions for obtaining authentic mass spectra are to include all additional analytes listed in Tables 1 and 2 of this attachment.

Section 6.13 The calibration solutions are modified to include the analytes listed in Tables 1 and 2 and the labeled compounds listed in Tables 5 and 6 of this attachment.

Section 6.14 The precision and recovery standard is modified to include the analytes listed in Tables 1 and 2 and the labeled compounds listed in Tables 5 and 6 of this attachment.

Section 6.15 The solutions containing the additional analytes listed in Tables 1 and 2 of this attachment are to be analyzed for stability.

Section 7.2.1 This section is modified to include the analytes listed in Tables 1 and 2 and the labeled compounds listed in Tables 5 and 6 of this attachment.

Section 7.4.5 This section is modified to include the analytes listed in Tables 1 and 2 and the labeled compounds listed in Tables 5 and 6 in the calibration.

Section 8.2 The initial precision and recovery (IPR) requirements are modified to include the analytes listed in Tables 1 and 2 and the labeled compounds listed in Tables 5 and 6 of this attachment. Additional IPR performance criteria are supplied in Table 7 of this attachment.

Section 8.3 The labeled compounds listed in Tables 3 and 4 of this attachment are to be included in the method performance tests. Additional method performance criteria are supplied in Table 7 of this attachment.

Section 8.5.2 The acceptance criteria for blanks includes the analytes listed in Tables 1 and 2 of this attachment.

Section 10.1.2 The labeled compound solution must include the labeled compounds listed in Tables 5 and 6 of this attachment.

Section 10.1.3 The precision and recovery standard must include the analytes listed in Tables 1 and 2 and the labeled compounds listed in Tables 5 and 6 of this attachment.

Section 12.5 Additional QC requirements for calibration verification are supplied in Table 7 of this attachment.

Section 12.7 Additional QC requirements for ongoing precision and recovery are supplied in Table 7 of this attachment.

Table 1—Base/Neutral Extractable Compounds

Compound
Pollutant
CAS

Registry
EPA-EGD
acetophenone
1		98-86-2758
aniline
2		62-53-3757
-2,3-dichloroaniline
1		608-27-5578
-o-cresol
1		95-48-7771
pyridine
2		110-86-11330

CAS = Chemical Abstracts Registry.

EGD = Effluent Guidelines Division.


1 Analysis of this pollutant is approved only for the Centralized Waste Treatment industry.


2 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


Table 2—Acid Extractable Compounds

Compound
Pollutant
CAS

Registry
EPA-EGD
p-cresol
1		106-44-51744

CAS = Chemical Abstracts Registry.

EGD = Effluent Guidelines Division.


1 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


Table 3—Gas Chromatography
1 of Base/Neutral Extractable Compounds

EGD No.
Compound
Retention time
2
Minimum

level
3

(µg/L)
EGD No.
Compound
Retention time
2
Minimum level
3

(µg/L)
Mean

(sec)
EGD Ref
Relative
Mean

(sec)
EGD Ref
Relative
758acetophenone
4		8186581.003-1.00510
757aniline
5		6946570.994-1.02310
5782,3-dichloroaniline
4		11601641.003-1.00710
771o-cresol
4		8146711.005-1.00910
1330pyridine
5		37812301.005-1.01110

EGD = Effluent Guidelines Division.


1 The data presented in this table were obtained under the chromatographic conditions given in the footnote to Table 3 of EPA Method 1625B.


2 Retention times are approximate and are intended to be consistent with the retention times for the analytes in EPA Method 1625B.


3 See the definition in footnote 2 to Table 3 of EPA Method 1625B.


4 Analysis of this pollutant is approved only for the Centralized Waste Treatment industry.


5 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


Table 4—Gas Chromatography
1 of Acid Extractable Compounds

EGD No.
Compound
Retention time
2
Minimum

level

(µ/L)
3
Mean

(sec)
EGD Ref
Relative
1744p-cresol
4		83416441.004-1.00820

EGD = Effluent Guidelines Division.


1 The data presented in this table were obtained under the chromatographic conditions given in the footnote to Table 4 of EPA Method 1625B.


2 Retention times are approximate and are intended to be consistent with the retention times for the analytes in EPA Method 1625B.


3 See the definition in footnote 2 to Table 4 of EPA Method 1625B.


4 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


Table 5—Base/Neutral Extractable Compound Characteristic m/z’s

Compound
Labeled Analog
Primary

m/z
1
acetophenone
2		d5105/110
aniline
3		d793/100
o-cresol
2		d7108/116
2,3-dichloroaniline
2		n/a161
pyridine
3		d579/84

m/z = mass to charge ratio.


1 Native/labeled.


2 Analysis of this pollutant is approved only for the Centralized Waste Treatment industry.


3 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


Table 6—Acid Extractable Compound Characteristic m/z’s

Compound
Labeled Analog
Primary

m/z
1
p-cresol
2		d7108/116

m/z = mass to charge ratio.


1 Native/labeled.


2 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


Table 7—Acceptance Criteria for Performance Tests

EGD No.
Compound
Acceptance criteria
Calibration verification sec. 12.5

µg/mL)
On-going accuracy sec. 12.7 R

(µg/L)
Initial precision and accuracy section 8.2

(µg/L)
Labeled compound recovery sec. 8.3 and 14.2 P

(percent)
s

(µg/L)
X
758acetophenone
1		3444-16785-11545-162
658acetophenone-d 5
1		5123-25445-16285-11522-264
757aniline
2		3230-17185-11533-154
657aniline-d 7
2		7115-27833-15485-11512-344
771o-cresol
1		4031-22685-11535-196
671o-cresol-d 7
1		2330-14635-19685-11531-142
1744p-cresol
2		5954-14085-11537-203
1644p-cresol-d7
2		2211-61837-20385-11516-415
5782,3-dichloroaniline
1		1340-16085-11544-144
1330pyridine
2		2810-42183-11718-238
1230pyridine-d 5
2		ns7-39219-23885-1154-621

s = Standard deviation of four recovery measurements.

X = Average recovery for four recovery measurements.

EGD = Effluent Guidelines Division.

ns = no specification; limit is outside the range that can be measured reliably.


1 Analysis of this pollutant is approved only for the Centralized Waste Treatment industry.


2 Analysis of this pollutant is approved only for the Centralized Waste Treatment and Landfills industries.


[49 FR 43261, Oct. 26, 1984; 50 FR 692, 695, Jan. 4, 1985, as amended at 51 FR 23702, June 30, 1986; 62 FR 48405, Sept. 15, 1997; 65 FR 3044, Jan. 19, 2000; 65 FR 81295, 81298, Dec. 22, 2000; 82 FR 40875, Aug. 28, 2017]


Appendix B to Part 136—Definition and Procedure for the Determination of the Method Detection Limit—Revision 2

Definition

The method detection limit (MDL) is defined as the minimum measured concentration of a substance that can be reported with 99% confidence that the measured concentration is distinguishable from method blank results.


I. Scope and Application

(1) The MDL procedure is designed to be a straightforward technique for estimation of the detection limit for a broad variety of physical and chemical methods. The procedure requires a complete, specific, and well-defined analytical method. It is essential that all sample processing steps used by the laboratory be included in the determination of the method detection limit.


(2) The MDL procedure is not applicable to methods that do not produce results with a continuous distribution, such as, but not limited to, methods for whole effluent toxicity, presence/absence methods, and microbiological methods that involve counting colonies. The MDL procedure also is not applicable to measurements such as, but not limited to, biochemical oxygen demand, color, pH, specific conductance, many titration methods, and any method where low-level spiked samples cannot be prepared. Except as described in the addendum, for the purposes of this procedure, “spiked samples” are prepared from a clean reference matrix, such as reagent water, spiked with a known and consistent quantity of the analyte. MDL determinations using spiked samples may not be appropriate for all gravimetric methods (e.g., residue or total suspended solids), but an MDL based on method blanks can be determined in such instances.


II. Procedure

(1) Estimate the initial MDL using one or more of the following:


(a) The mean determined concentration plus three times the standard deviation of a set of method blanks.


(b) The concentration value that corresponds to an instrument signal-to-noise ratio in the range of 3 to 5.


(c) The concentration equivalent to three times the standard deviation of replicate instrumental measurements of spiked blanks.


(d) That region of the calibration where there is a significant change in sensitivity, i.e., a break in the slope of the calibration.


(e) Instrumental limitations.


(f) Previously determined MDL.



Note:

It is recognized that the experience of the analyst is important to this process. However, the analyst should include some or all of the above considerations in the initial estimate of the MDL.


(2) Determine the initial MDL.



Note:

The Initial MDL is used when the laboratory does not have adequate data to perform the Ongoing Annual Verification specified in Section (4), typically when a new method is implemented or if a method was rarely used in the last 24 months.


(a) Select a spiking level, typically 2—10 times the estimated MDL in Section 1. Spiking levels in excess of 10 times the estimated detection limit may be required for analytes with very poor recovery (e.g., for an analyte with 10% recovery, spiked at 100 micrograms/L, with mean recovery of 10 micrograms/L; the calculated MDL may be around 3 micrograms/L. Therefore, in this example, the spiking level would be 33 times the MDL, but spiking lower may result in no recovery at all).


(b) Process a minimum of seven spiked samples and seven method blank samples through all steps of the method. The samples used for the MDL must be prepared in at least three batches on three separate calendar dates and analyzed on three separate calendar dates. (Preparation and analysis may be on the same day.) Existing data may be used, if compliant with the requirements for at least three batches, and generated within the last twenty four months. The most recent available data for method blanks and spiked samples must be used. Statistical outlier removal procedures should not be used to remove data for the initial MDL determination, since the total number of observations is small and the purpose of the MDL procedure is to capture routine method variability. However, documented instances of gross failures (e.g., instrument malfunctions, mislabeled samples, cracked vials) may be excluded from the calculations, provided that at least seven spiked samples and seven method blanks are available. (The rationale for removal of specific outliers must be documented and maintained on file with the results of the MDL determination.)


(i) If there are multiple instruments that will be assigned the same MDL, then the sample analyses must be distributed across all of the instruments.


(ii) A minimum of two spiked samples and two method blank samples prepared and analyzed on different calendar dates is required for each instrument. Each analytical batch may contain one spiked sample and one method blank sample run together. A spiked sample and a method blank sample may be analyzed in the same batch, but are not required to be.


(iii) The same prepared extract may be analyzed on multiple instruments so long as the minimum requirement of seven preparations in at least three separate batches is maintained.


(c) Evaluate the spiking level: If any result for any individual analyte from the spiked samples does not meet the method qualitative identification criteria or does not provide a numerical result greater than zero, then repeat the spiked samples at a higher concentration. (Qualitative identification criteria are a set of rules or guidelines for establishing the identification or presence of an analyte using a measurement system. Qualitative identification does not ensure that quantitative results for the analyte can be obtained.)


(d) Make all computations as specified in the analytical method and express the final results in the method-specified reporting units.


(i) Calculate the sample standard deviation (S) of the replicate spiked sample measurements and the sample standard deviation of the replicate method blank measurements from all instruments to which the MDL will be applied.


(ii) Compute the MDLs (the MDL based on spiked samples) as follows:


MDLS = t(n −1, 1−α = 0.99)Ss

Where:

MDLs = the method detection limit based on spiked samples

t(n-1, 1−α = 0.99) = the Student’s t-value appropriate for a single-tailed 99th percentile t statistic and a standard deviation estimate with n-1 degrees of freedom. See Addendum Table 1.

Ss = sample standard deviation of the replicate spiked sample analyses.

(iii) Compute the MDLb (the MDL based on method blanks) as follows:


(A) If none of the method blanks give numerical results for an individual analyte, the MDLb does not apply. A numerical result includes both positive and negative results, including results below the current MDL, but not results of “ND” (not detected) commonly observed when a peak is not present in chromatographic analysis.


(B) If some (but not all) of the method blanks for an individual analyte give numerical results, set the MDLb equal to the highest method blank result. If more than 100 method blanks are available, set MDLb to the level that is no less than the 99th percentile of the method blank results. For “n” method blanks where n ≥ 100, sort the method blanks in rank order. The (n * 0.99) ranked method blank result (round to the nearest whole number) is the MDLb. For example, to find MDLb from a set of 164 method blanks where the highest ranked method blank results are . . . 1.5, 1.7, 1.9, 5.0, and 10, then 164 × 0.99 = 162.36 which rounds to the 162nd method blank result. Therefore, MDLb is 1.9 for n = 164 (10 is the 164th result, 5.0 is the 163rd result, and 1.9 is the 162nd result). Alternatively, you may use spreadsheet algorithms to calculate the 99th percentile to interpolate between the ranks more precisely.


(C) If all of the method blanks for an individual analyte give numerical results, then calculate the MDLb as:


MDLb = X + tn−1,1−α = (0.99)Sb

Where:

MDLb = the MDL based on method blanks

X = mean of the method blank results (use zero in place of the mean if the mean is negative)

t(n−1, 1α = 0.99) = the Student’s t-value appropriate for the single-tailed 99th percentile t statistic and a standard deviation estimate with n−1 degrees of freedom. See Addendum Table 1.

Sb = sample standard deviation of the replicate method blank sample analyses.


Note:

If 100 or more method blanks are available, as an option, MDLb may be set to the concentration that is greater than or equal to the 99th percentile of the method blank results, as described in Section (2)(d)(iii)(B).


(e) Select the greater of MDLs or MDLb as the initial MDL.


(3) Ongoing Data Collection.


(a) During any quarter in which samples are being analyzed, prepare and analyze a minimum of two spiked samples on each instrument, in separate batches, using the same spiking concentration used in Section 2. If any analytes are repeatedly not detected in the quarterly spiked sample analyses, or do not meet the qualitative identification criteria of the method (see section 2(c) of this procedure), then this is an indication that the spiking level is not high enough and should be adjusted upward. Note that it is not necessary to analyze additional method blanks together with the spiked samples, the method blank population should include all of the routine method blanks analyzed with each batch during the course of sample analysis.


(b) Ensure that at least seven spiked samples and seven method blanks are completed for the annual verification. If only one instrument is in use, a minimum of seven spikes are still required, but they may be drawn from the last two years of data collection.


(c) At least once per year, re-evaluate the spiking level.


(i) If more than 5% of the spiked samples do not return positive numerical results that meet all method qualitative identification criteria, then the spiking level must be increased and the initial MDL re-determined following the procedure in section 2.


(ii) [Reserved]


(d) If the method is altered in a way that can be reasonably expected to change its sensitivity, then re-determine the initial MDL according to section 2, and the restart the ongoing data collection.


(e) If a new instrument is added to a group of instruments whose data are being pooled to create a single MDL, analyze a minimum of two spiked replicates and two method blank replicates on the new instrument. If both method blank results are below the existing MDL, then the existing MDLb is validated. Combine the new spiked sample results to the existing spiked sample results and recalculate the MDLs as in Section 4. If the recalculated MDLs does not vary by more than the factor specified in section 4(f) of this procedure, then the existing MDLs is validated. If either of these two conditions is not met, then calculate a new MDL following the instructions in section 2.


(4) Ongoing Annual Verification.


(a) At least once every thirteen months, re-calculate MDLs and MDLb from the collected spiked samples and method blank results using the equations in section 2.


(b) Include data generated within the last twenty four months, but only data with the same spiking level. Only documented instances of gross failures (e.g., instrument malfunctions, mislabeled samples, cracked vials) may be excluded from the calculations. (The rationale for removal of specific outliers must be documented and maintained on file with the results of the MDL determination.) If the laboratory believes the sensitivity of the method has changed significantly, then the most recent data available may be used, maintaining compliance with the requirement for at least seven replicates in three separate batches on three separate days (see section 2b).


(c) Include the initial MDL spiked samples, if the data were generated within twenty four months.


(d) Only use data associated with acceptable calibrations and batch QC. Include all routine data, with the exception of batches that are rejected and the associated samples reanalyzed. If the method has been altered in a way that can be reasonably expected to change its sensitivity, then use only data collected after the change.


(e) Ideally, use all method blank results from the last 24 months for the MDLb calculation. The laboratory has the option to use only the last six months of method blank data or the fifty most recent method blanks, whichever criteria yields the greater number of method blanks.


(f) The verified MDL is the greater of the MDLs or MDLb. If the verified MDL is within 0.5 to 2.0 times the existing MDL, and fewer than 3% of the method blank results (for the individual analyte) have numerical results above the existing MDL, then the existing MDL may optionally be left unchanged. Otherwise, adjust the MDL to the new verification MDL. (The range of 0.5 to 2.0 approximates the 95th percentile confidence interval for the initial MDL determination with six degrees of freedom.)


Addendum to Section II: Determination of the MDL for a Specific Matrix

The MDL may be determined in a specific sample matrix as well as in reagent water.


(1) Analyze the sample matrix to determine the native (background) concentration of the analyte(s) of interest.


(2) If the response for the native concentration is at a signal-to-noise ratio of approximately 5-20, determine the matrix-specific MDL according to Section 2 but without spiking additional analyte.


(3) Calculate MDLb using the method blanks, not the sample matrix.


(4) If the signal-to-noise ratio is less than 5, then the analyte(s) should be spiked into the sample matrix to obtain a concentration that will give results with a signal-to-noise ratio of approximately 10-20.


(5) If the analytes(s) of interest have signal-to-noise ratio(s) greater than approximately 20, then the resulting MDL is likely to be biased high.


Table 1—Single-Tailed 99th Percentile t Statistic

Number of replicates
Degrees of freedom

(n−1)
t (n−1, 0.99)
763.143
872.998
982.896
1092.821
11102.764
16152.602
21202.528
26252.485
31302.457
32312.453
48472.408
50492.405
61602.390
64632.387
80792.374
96952.366
100992.365

III. Documentation

The analytical method used must be specifically identified by number or title and the MDL for each analyte expressed in the appropriate method reporting units. Data and calculations used to establish the MDL must be able to be reconstructed upon request. The sample matrix used to determine the MDL must also be identified with MDL value. Document the mean spiked and recovered analyte levels with the MDL. The rationale for removal of outlier results, if any, must be documented and maintained on file with the results of the MDL determination.


[82 FR 40939, Aug. 28, 2017]


Appendix C to Part 136—Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry Method 200.7

1.0 Scope and Application

1.1 Inductively coupled plasma-atomic emission spectrometry (ICP-AES) is used to determine metals and some nonmetals in solution. This method is a consolidation of existing methods for water, wastewater, and solid wastes.1-4 (For analysis of petroleum products see References 5 and 6, Section 16.0). This method is applicable to the following analytes:


Analyte
Chemical abstract services registry

number (CASRN)
Aluminum (Al)7429-90-5
Antimony (Sb)7440-36-0
Arsenic (As)7440-38-2
Barium (Ba)7440-39-3
Beryllium (Be)7440-41-7
Boron (B)7440-42-8
Cadmium (Cd)7440-43-9
Calcium (Ca)7440-70-2
Cerium
a (Cr)		7440-45-1
Chromium (Cr)7440-47-3
Cobalt (Co)7440-48-4
Copper (Cu)7440-50-8
Iron (Fe)7439-89-6
Lead (Pb)7439-92-1
Lithium (Li)7439-93-2
Magnesium (Mg)7439-95-4
Manganese (Mn)7439-96-5
Mercury (Hg)7439-97-6
Molybdenum (Mo)7439-98-7
Nickel (Ni)7440-02-0
Phosphorus (P)7723-14-0
Potassium (K)7440-09-7
Selenium (Se)7782-49-2
Silica
b (Si02)		7631-86-9
Silver (Ag)7440-22-4
Sodium (Na)7440-23-5
Strontium (Sr)7440-24-6
Thallium (Tl)7440-28-0
Tin (Sn)7440-31-5
Titanium (Ti)7440-32-6
Vanadium (V)7440-62-2
Zinc (Zn)7440-66-6


a Cerium has been included as method analyte for correction of potential interelement spectral interference.


b This method is not suitable for the determination of silica in solids.


1.2 For reference where this method is approved for use in compliance monitoring programs [e.g., Clean Water Act (NPDES) or Safe Drinking Water Act (SDWA)] consult both the appropriate sections of the Code of Federal Regulation (40 CFR Part 136 Table 1B for NPDES, and Part 141 § 141.23 for drinking water), and the latest Federal Register announcements.


1.3 ICP-AES can be used to determine dissolved analytes in aqueous samples after suitable filtration and acid preservation. To reduce potential interferences, dissolved solids should be

1.4 With the exception of silver, where this method is approved for the determination of certain metal and metalloid contaminants in drinking water, samples may be analyzed directly by pneumatic nebulization without acid digestion if the sample has been properly preserved with acid and has turbidity of

1.5 For the determination of total recoverable analytes in aqueous and solid samples a digestion/extraction is required prior to analysis when the elements are not in solution (e.g., soils, sludges, sediments and aqueous samples that may contain particulate and suspended solids). Aqueous samples containing suspended or particulate material 1% (w/v) should be extracted as a solid type sample.


1.6 When determining boron and silica in aqueous samples, only plastic, PTFE or quartz labware should be used from time of sample collection to completion of analysis. For accurate determination of boron in solid samples only quartz or PTFE beakers should be used during acid extraction with immediate transfer of an extract aliquot to a plastic centrifuge tube following dilution of the extract to volume. When possible, borosilicate glass should be avoided to prevent contamination of these analytes.


1.7 Silver is only slightly soluble in the presence of chloride unless there is a sufficient chloride concentration to form the soluble chloride complex. Therefore, low recoveries of silver may occur in samples, fortified sample matrices and even fortified blanks if determined as a dissolved analyte or by “direct analysis” where the sample has not been processed using the total recoverable mixed acid digestion. For this reason it is recommended that samples be digested prior to the determination of silver. The total recoverable sample digestion procedure given in this method is suitable for the determination of silver in aqueous samples containing concentrations up to 0.1 mg/L. For the analysis of wastewater samples containing higher concentrations of silver, succeeding smaller volume, well mixed aliquots should be prepared until the analysis solution contains 50 mg/kg should be treated in a similar manner. Also, the extraction of tin from solid samples should be prepared again using aliquots

1.8 The total recoverable sample digestion procedure given in this method will solubilize and hold in solution only minimal concentrations of barium in the presence of free sulfate. For the analysis of barium in samples having varying and unknown concentrations of sulfate, analysis should be completed as soon as possible after sample preparation.


1.9 The total recoverable sample digestion procedure given in this method is not suitable for the determination of volatile organo-mercury compounds. However, if digestion is not required (turbidity 3 + HCl) matrix as the total recoverable calibration standards and blank solutions.


1.10 Detection limits and linear ranges for the elements will vary with the wavelength selected, the spectrometer, and the matrices. Table 1 provides estimated instrument detection limits for the listed wavelengths.
7 However, actual method detection limits and linear working ranges will be dependent on the sample matrix, instrumentation, and selected operating conditions.


1.11 Users of the method data should state the data-quality objectives prior to analysis. Users of the method must document and have on file the required initial demonstration performance data described in Section 9.2 prior to using the method for analysis.


2.0 Summary of Method

2.1 An aliquot of a well mixed, homogeneous aqueous or solid sample is accurately weighed or measured for sample processing. For total recoverable analysis of a solid or an aqueous sample containing undissolved material, analytes are first solubilized by gentle refluxing with nitric and hydrochloric acids. After cooling, the sample is made up to volume, is mixed and centrifuged or allowed to settle overnight prior to analysis. For the determination of dissolved analytes in a filtered aqueous sample aliquot, or for the “direct analysis” total recoverable determination of analytes in drinking water where sample turbidity is

2.2 The analysis described in this method involves multielemental determinations by ICP-AES using sequential or simultaneous instruments. The instruments measure characteristic atomic-line emission spectra by optical spectrometry. Samples are nebulized and the resulting aerosol is transported to the plasma torch. Element specific emission spectra are produced by a radio-frequency inductively coupled plasma. The spectra are dispersed by a grating spectrometer, and the intensities of the line spectra are monitored at specific wavelengths by a photosensitive device. Photocurrents from the photosensitive device are processed and controlled by a computer system. A background correction technique is required to compensate for variable background contribution to the determination of the analytes. Background must be measured adjacent to the analyte wavelength during analysis. Various interferences must be considered and addressed appropriately as discussed in Sections 4.0, 7.0, 9.0, 10.0, and 11.0.


3.0 Definitions

3.1 Calibration Blank—A volume of reagent water acidified with the same acid matrix as in the calibration standards. The calibration blank is a zero standard and is used to calibrate the ICP instrument (Section 7.10.1).


3.2 Calibration Standard (CAL)—A solution prepared from the dilution of stock standard solutions. The CAL solutions are used to calibrate the instrument response with respect to analyte concentration (Section 7.9).


3.3 Dissolved Analyte—The concentration of analyte in an aqueous sample that will pass through a 0.45 µm membrane filter assembly prior to sample acidification (Section 11.1).


3.4 Field Reagent Blank (FRB)—An aliquot of reagent water or other blank matrix that is placed in a sample container in the laboratory and treated as a sample in all respects, including shipment to the sampling site, exposure to the sampling site conditions, storage, preservation, and all analytical procedures. The purpose of the FRB is to determine if method analytes or other interferences are present in the field environment (Section 8.5).


3.5 Instrument Detection Limit (IDL)—The concentration equivalent to the analyte signal which is equal to three times the standard deviation of a series of 10 replicate measurements of the calibration blank signal at the same wavelength (Table 1.).


3.6 Instrument Performance Check (IPC) Solution—A solution of method analytes, used to evaluate the performance of the instrument system with respect to a defined set of method criteria (Sections 7.11 and 9.3.4).


3.7 Internal Standard—Pure analyte(s) added to a sample, extract, or standard solution in known amount(s) and used to measure the relative responses of other method analytes that are components of the same sample or solution. The internal standard must be an analyte that is not a sample component (Section 11.5).


3.8 Laboratory Duplicates (LD1 and LD2)—Two aliquots of the same sample taken in the laboratory and analyzed separately with identical procedures. Analyses of LD1 and LD2 indicate precision associated with laboratory procedures, but not with sample collection, preservation, or storage procedures.


3.9 Laboratory Fortified Blank (LFB)—An aliquot of LRB to which known quantities of the method analytes are added in the laboratory. The LFB is analyzed exactly like a sample, and its purpose is to determine whether the methodology is in control and whether the laboratory is capable of making accurate and precise measurements (Sections 7.10.3 and 9.3.2).


3.10 Laboratory Fortified Sample Matrix (LFM)—An aliquot of an environmental sample to which known quantities of the method analytes are added in the laboratory. The LFM is analyzed exactly like a sample, and its purpose is to determine whether the sample matrix contributes bias to the analytical results. The background concentrations of the analytes in the sample matrix must be determined in a separate aliquot and the measured values in the LFM corrected for background concentrations (Section 9.4).


3.11 Laboratory Reagent Blank (LRB)—An aliquot of reagent water or other blank matrices that are treated exactly as a sample including exposure to all glassware, equipment, solvents, reagents, and internal standards that are used with other samples. The LRB is used to determine if method analytes or other interferences are present in the laboratory environment, reagents, or apparatus (Sections 7.10.2 and 9.3.1).


3.12 Linear Dynamic Range (LDR)—The concentration range over which the instrument response to an analyte is linear (Section 9.2.2).


3.13 Method Detection Limit (MDL)—The minimum concentration of an analyte that can be identified, measured, and reported with 99% confidence that the analyte concentration is greater than zero (Section 9.2.4 and Table 4.).


3.14 Plasma Solution—A solution that is used to determine the optimum height above the work coil for viewing the plasma (Sections 7.15 and 10.2.3).


3.15 Quality Control Sample (QCS)—A solution of method analytes of known concentrations which is used to fortify an aliquot of LRB or sample matrix. The QCS is obtained from a source external to the laboratory and different from the source of calibration standards. It is used to check either laboratory or instrument performance (Sections 7.12 and 9.2.3).


3.16 Solid Sample—For the purpose of this method, a sample taken from material classified as soil, sediment or sludge.


3.17 Spectral Interference Check (SIC) Solution—A solution of selected method analytes of higher concentrations which is used to evaluate the procedural routine for correcting known interelement spectral interferences with respect to a defined set of method criteria (Sections 7.13, 7.14 and 9.3.5).


3.18 Standard Addition—The addition of a known amount of analyte to the sample in order to determine the relative response of the detector to an analyte within the sample matrix. The relative response is then used to assess either an operative matrix effect or the sample analyte concentration (Sections 9.5.1 and 11.5).


3.19 Stock Standard Solution—A concentrated solution containing one or more method analytes prepared in the laboratory using assayed reference materials or purchased from a reputable commercial source (Section 7.8).


3.20 Total Recoverable Analyte—The concentration of analyte determined either by “direct analysis” of an unfiltered acid preserved drinking water sample with turbidity of

3.21 Water Sample—For the purpose of this method, a sample taken from one of the following sources: drinking, surface, ground, storm runoff, industrial or domestic wastewater.


4.0 Interferences

4.1 Spectral interferences are caused by background emission from continuous or recombination phenomena, stray light from the line emission of high concentration elements, overlap of a spectral line from another element, or unresolved overlap of molecular band spectra.


4.1.1 Background emission and stray light can usually be compensated for by subtracting the background emission determined by measurement(s) adjacent to the analyte wavelength peak. Spectral scans of samples or single element solutions in the analyte regions may indicate not only when alternate wavelengths are desirable because of severe spectral interference, but also will show whether the most appropriate estimate of the background emission is provided by an interpolation from measurements on both sides of the wavelength peak or by the measured emission on one side or the other. The location(s) selected for the measurement of background intensity will be determined by the complexity of the spectrum adjacent to the wavelength peak. The location(s) used for routine measurement must be free of off-line spectral interference (interelement or molecular) or adequately corrected to reflect the same change in background intensity as occurs at the wavelength peak.


4.1.2 Spectral overlaps may be avoided by using an alternate wavelength or can be compensated for by equations that correct for interelement contributions, which involves measuring the interfering elements. Some potential on-line spectral interferences observed for the recommended wavelengths are given in Table 2. When operative and uncorrected, these interferences will produce false-positive determinations and be reported as analyte concentrations. The interferences listed are only those that occur between method analytes. Only interferences of a direct overlap nature that were observed with a single instrument having a working resolution of 0.035 nm are listed. More extensive information on interferant effects at various wavelengths and resolutions is available in Boumans’ Tables.
8 Users may apply interelement correction factors determined on their instruments within tested concentration ranges to compensate (off-line or on-line) for the effects of interfering elements.


4.1.3 When interelement corrections are applied, there is a need to verify their accuracy by analyzing spectral interference check solutions as described in Section 7.13. Interelement corrections will vary for the same emission line among instruments because of differences in resolution, as determined by the grating plus the entrance and exit slit widths, and by the order of dispersion. Interelement corrections will also vary depending upon the choice of background correction points. Selecting a background correction point where an interfering emission line may appear should be avoided when practical. Interelement corrections that constitute a major portion of an emission signal may not yield accurate data. Users should not forget that some samples may contain uncommon elements that could contribute spectral interferences.
7 8


4.1.4 The interference effects must be evaluated for each individual instrument whether configured as a sequential or simultaneous instrument. For each instrument, intensities will vary not only with optical resolution but also with operating conditions (such as power, viewing height and argon flow rate). When using the recommended wavelengths given in Table 1, the analyst is required to determine and document for each wavelength the effect from the known interferences given in Table 2, and to utilize a computer routine for their automatic correction on all analyses. To determine the appropriate location for off-line background correction, the user must scan the area on either side adjacent to the wavelength and record the apparent emission intensity from all other method analytes. This spectral information must be documented and kept on file. The location selected for background correction must be either free of off-line interelement spectral interference or a computer routine must be used for their automatic correction on all determinations. If a wavelength other than the recommended wavelength is used, the user must determine and document both the on-line and off-line spectral interference effect from all method analytes and provide for their automatic correction on all analyses. Tests to determine the spectral interference must be done using analyte concentrations that will adequately describe the interference. Normally, 100 mg/L single element solutions are sufficient, however, for analytes such as iron that may be found at high concentration a more appropriate test would be to use a concentration near the upper LDR limit. See Section 10.4 for required spectral interference test criteria.


4.1.5 When interelement corrections are not used, either on-going SIC solutions (Section 7.14) must be analyzed to verify the absence of interelement spectral interference or a computer software routine must be employed for comparing the determinative data to limits files for notifying the analyst when an interfering element is detected in the sample at a concentration that will produce either an apparent false positive concentration, greater than the analyte IDL, or false negative analyte concentration, less than the 99% lower control limit of the calibration blank. When the interference accounts for 10% or more of the analyte concentration, either an alternate wavelength free of interference or another approved test procedure must be used to complete the analysis. For example, the copper peak at 213.853 nm could be mistaken for the zinc peak at 213.856 nm in solutions with high copper and low zinc concentrations. For this example, a spectral scan in the 213.8 nm region would not reveal the misidentification because a single peak near the zinc location would be observed. The possibility of this misidentification of copper for the zinc peak at 213.856 nm can be identified by measuring the copper at another emission line, e.g., 324.754 nm. Users should be aware that, depending upon the instrumental resolution, alternate wavelengths with adequate sensitivity and freedom from interference may not be available for all matrices. In these circumstances the analyte must be determined using another approved test procedure.


4.2 Physical interferences are effects associated with the sample nebulization and transport processes. Changes in viscosity and surface tension can cause significant inaccuracies, especially in samples containing high dissolved solids or high acid concentrations. If physical interferences are present, they must be reduced by such means as a high-solids nebulizer, diluting the sample, using a peristaltic pump, or using an appropriate internal standard element. Another problem that can occur with high dissolved solids is salt buildup at the tip of the nebulizer, which affects aerosol flow rate and causes instrumental drift. This problem can be controlled by a high-solids nebulizer, wetting the argon prior to nebulization, using a tip washer, or diluting the sample. Also, it has been reported that better control of the argon flow rates, especially for the nebulizer, improves instrument stability and precision; this is accomplished with the use of mass flow controllers.


4.3 Chemical interferences include molecular-compound formation, ionization effects, and solute-vaporization effects. Normally, these effects are not significant with the ICP-AES technique. If observed, they can be minimized by careful selection of operating conditions (such as incident power and observation height), by buffering of the sample, by matrix matching, and by standard-addition procedures. Chemical interferences are highly dependent on matrix type and the specific analyte element.


4.4 Memory interferences result when analytes in a previous sample contribute to the signals measured in a new sample. Memory effects can result from sample deposition on the uptake tubing to the nebulizer, and from the buildup of sample material in the plasma torch and spray chamber. The site where these effects occur is dependent on the element and can be minimized by flushing the system with a rinse blank between samples (Section 7.10.4). The possibility of memory interferences should be recognized within an analytical run and suitable rinse times should be used to reduce them. The rinse times necessary for a particular element must be estimated prior to analysis. This may be achieved by aspirating a standard containing elements corresponding to either their LDR or a concentration ten times those usually encountered. The aspiration time should be the same as a normal sample analysis period, followed by analysis of the rinse blank at designated intervals. The length of time required to reduce analyte signals to within a factor of two of the method detection limit, should be noted. Until the required rinse time is established, this method requires a rinse period of at least 60 seconds between samples and standards. If a memory interference is suspected, the sample must be re-analyzed after a long rinse period.


5.0 Safety

5.1 The toxicity or carcinogenicity of each reagent used in this method have not been fully established. Each chemical should be regarded as a potential health hazard and exposure to these compounds should be as low as reasonably achievable. Each laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method.9-12 A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Specifically, concentrated nitric and hydrochloric acids present various hazards and are moderately toxic and extremely irritating to skin and mucus membranes. Use these reagents in a fume hood whenever possible and if eye or skin contact occurs, flush with large volumes of water. Always wear safety glasses or a shield for eye protection, protective clothing and observe proper mixing when working with these reagents.


5.2 The acidification of samples containing reactive materials may result in the release of toxic gases, such as cyanides or sulfides. Acidification of samples should be done in a fume hood.


5.3 All personnel handling environmental samples known to contain or to have been in contact with human waste should be immunized against known disease causative agents.


5.4 The inductively coupled plasma should only be viewed with proper eye protection from the ultraviolet emissions.


5.5 It is the responsibility of the user of this method to comply with relevant disposal and waste regulations. For guidance see Sections 14.0 and 15.0.


6.0 Equipment and Supplies

6.1 Inductively coupled plasma emission spectrometer:


6.1.1 Computer-controlled emission spectrometer with background-correction capability.


The spectrometer must be capable of meeting and complying with the requirements described and referenced in Section 2.2.

6.1.2 Radio-frequency generator compliant with FCC regulations.


6.1.3 Argon gas supply—High purity grade (99.99%). When analyses are conducted frequently, liquid argon is more economical and requires less frequent replacement of tanks than compressed argon in conventional cylinders.


6.1.4 A variable speed peristaltic pump is required to deliver both standard and sample solutions to the nebulizer.


6.1.5 (Optional) Mass flow controllers to regulate the argon flow rates, especially the aerosol transport gas, are highly recommended. Their use will provide more exacting control of reproducible plasma conditions.


6.2 Analytical balance, with capability to measure to 0.1 mg, for use in weighing solids, for preparing standards, and for determining dissolved solids in digests or extracts.


6.3 A temperature adjustable hot plate capable of maintaining a temperature of 95 °C.


6.4 (Optional) A temperature adjustable block digester capable of maintaining a temperature of 95 °C and equipped with 250 mL constricted digestion tubes.


6.5 (Optional) A steel cabinet centrifuge with guard bowl, electric timer and brake.


6.6 A gravity convection drying oven with thermostatic control capable of maintaining 180 °C ±5 °C.


6.7 (Optional) An air displacement pipetter capable of delivering volumes ranging from 0.1-2500 µL with an assortment of high quality disposable pipet tips.


6.8 Mortar and pestle, ceramic or nonmetallic material.


6.9 Polypropylene sieve, 5-mesh (4 mm opening).


6.10 Labware—For determination of trace levels of elements, contamination and loss are of prime consideration. Potential contamination sources include improperly cleaned laboratory apparatus and general contamination within the laboratory environment from dust, etc. A clean laboratory work area designated for trace element sample handling must be used. Sample containers can introduce positive and negative errors in the determination of trace elements by contributing contaminants through surface desorption or leaching, or depleting element concentrations through adsorption processes. All reusable labware (glass, quartz, polyethylene, PTFE, FEP, etc.) should be sufficiently clean for the task objectives. Several procedures found to provide clean labware include washing with a detergent solution, rinsing with tap water, soaking for four hours or more in 20% (v/v) nitric acid or a mixture of HNO3 and HCl (1 + 2 + 9), rinsing with reagent water and storing clean.
2 3 Chromic acid cleaning solutions must be avoided because chromium is an analyte.


6.10.1 Glassware—Volumetric flasks, graduated cylinders, funnels and centrifuge tubes (glass and/or metal-free plastic).


6.10.2 Assorted calibrated pipettes.


6.10.3 Conical Phillips beakers (Corning 1080-250 or equivalent), 250 mL with 50 mm watch glasses.


6.10.4 Griffin beakers, 250 mL with 75 mm watch glasses and (optional) 75 mm ribbed watch glasses.


6.10.5 (Optional) PTFE and/or quartz Griffin beakers, 250 mL with PTFE covers.


6.10.6 Evaporating dishes or high-form crucibles, porcelain, 100 mL capacity.


6.10.7 Narrow-mouth storage bottles, FEP (fluorinated ethylene propylene) with screw closure, 125 mL to 1 L capacities.


6.10.8 One-piece stem FEP wash bottle with screw closure, 125 mL capacity.


7.0 Reagents and Standards

7.1 Reagents may contain elemental impurities which might affect analytical data. Only high-purity reagents that conform to the American Chemical Society specifications
13 should be used whenever possible. If the purity of a reagent is in question, analyze for contamination. All acids used for this method must be of ultra high-purity grade or equivalent. Suitable acids are available from a number of manufacturers. Redistilled acids prepared by sub-boiling distillation are acceptable.


7.2 Hydrochloric acid, concentrated (sp.gr. 1.19)—HCl.


7.2.1 Hydrochloric acid (1 + 1)—Add 500 mL concentrated HCl to 400 mL reagent water and dilute to 1 L.


7.2.2 Hydrochloric acid (1 + 4)—Add 200 mL concentrated HCl to 400 mL reagent water and dilute to 1 L.


7.2.3 Hydrochloric acid (1 + 20)—Add 10 mL concentrated HCl to 200 mL reagent water.


7.3 Nitric acid, concentrated (sp.gr. 1.41)—HNO3.


7.3.1 Nitric acid (1 + 1)—Add 500 mL concentrated HNO3 to 400 mL reagent water and dilute to 1 L.


7.3.2 Nitric acid (1 + 2)—Add 100 mL concentrated HNO3 to 200 mL reagent water.


7.3.3 Nitric acid (1 + 5)—Add 50 mL concentrated HNO3 to 250 mL reagent water.


7.3.4 Nitric acid (1 + 9)—Add 10 mL concentrated HNO3 to 90 mL reagent water.


7.4 Reagent water. All references to water in this method refer to ASTM Type I grade water.
14


7.5 Ammonium hydroxide, concentrated (sp.gr. 0.902).


7.6 Tartaric acid, ACS reagent grade.


7.7 Hydrogen peroxide, 50%, stabilized certified reagent grade.


7.8 Standard Stock Solutions—Stock standards may be purchased or prepared from ultra-high purity grade chemicals (99.99-99.999% pure). All compounds must be dried for one hour at 105 °C, unless otherwise specified. It is recommended that stock solutions be stored in FEP bottles. Replace stock standards when succeeding dilutions for preparation of calibration standards cannot be verified.


CAUTION: Many of these chemicals are extremely toxic if inhaled or swallowed (Section 5.1). Wash hands thoroughly after handling.


Typical stock solution preparation procedures follow for 1 L quantities, but for the purpose of pollution prevention, the analyst is encouraged to prepare smaller quantities when possible. Concentrations are calculated based upon the weight of the pure element or upon the weight of the compound multiplied by the fraction of the analyte in the compound


From pure element,



where: gravimetric factor = the weight fraction of the analyte in the compound

7.8.1 Aluminum solution, stock, 1 mL = 1000 µg Al: Dissolve 1.000 g of aluminum metal, weighed accurately to at least four significant figures, in an acid mixture of 4.0 mL of (1 + 1) HCl and 1 mL of concentrated HNO3 in a beaker. Warm beaker slowly to effect solution. When dissolution is complete, transfer solution quantitatively to a 1 L flask, add an additional 10.0 mL of (1 + 1) HCl and dilute to volume with reagent water.


7.8.2 Antimony solution, stock, 1 mL = 1000 µg Sb: Dissolve 1.000 g of antimony powder, weighed accurately to at least four significant figures, in 20.0 mL (1 + 1) HNO3 and 10.0 mL concentrated HCl. Add 100 mL reagent water and 1.50 g tartaric acid. Warm solution slightly to effect complete dissolution. Cool solution and add reagent water to volume in a 1 L volumetric flask.


7.8.3 Arsenic solution, stock, 1 mL = 1000 µg As: Dissolve 1.320 g of As2O3 (As fraction = 0.7574), weighed accurately to at least four significant figures, in 100 mL of reagent water containing 10.0 mL concentrated NH4OH. Warm the solution gently to effect dissolution. Acidify the solution with 20.0 mL concentrated HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.4 Barium solution, stock, 1 mL = 1000 µg Ba: Dissolve 1.437 g BaCO3 (Ba fraction = 0.6960), weighed accurately to at least four significant figures, in 150 mL (1 + 2) HNO3 with heating and stirring to degas and dissolve compound. Let solution cool and dilute with reagent water in 1 L volumetric flask.


7.8.5 Beryllium solution, stock, 1 mL = 1000 µg Be: DO NOT DRY. Dissolve 19.66 g BeSO4•4H2O (Be fraction = 0.0509), weighed accurately to at least four significant figures, in reagent water, add 10.0 mL concentrated HNO3, and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.6 Boron solution, stock, 1 mL = 1000 µg B: DO NOT DRY. Dissolve 5.716 g anhydrous H3BO3 (B fraction = 0.1749), weighed accurately to at least four significant figures, in reagent water and dilute in a 1 L volumetric flask with reagent water. Transfer immediately after mixing to a clean FEP bottle to minimize any leaching of boron from the glass volumetric container. Use of a nonglass volumetric flask is recommended to avoid boron contamination from glassware.


7.8.7 Cadmium solution, stock, 1 mL = 1000 µg Cd: Dissolve 1.000 g Cd metal, acid cleaned with (1 + 9) HNO3, weighed accurately to at least four significant figures, in 50 mL (1 + 1) HNO3 with heating to effect dissolution. Let solution cool and dilute with reagent water in a 1 L volumetric flask.


7.8.8 Calcium solution, stock, 1 mL = 1000 µg Ca: Suspend 2.498 g CaCO3 (Ca fraction = 0.4005), dried at 180 °C for one hour before weighing, weighed accurately to at least four significant figures, in reagent water and dissolve cautiously with a minimum amount of (1 + 1) HNO3. Add 10.0 mL concentrated HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.9 Cerium solution, stock, 1 mL = 1000 µg Ce: Slurry 1.228 g CeO2 (Ce fraction = 0.8141), weighed accurately to at least four significant figures, in 100 mL concentrated HNO3 and evaporate to dryness. Slurry the residue in 20 mL H2O, add 50 mL concentrated HNO3, with heat and stirring add 60 mL 50% H2O2 dropwise in 1 mL increments allowing periods of stirring between the 1 mL additions. Boil off excess H2O2 before diluting to volume in a 1 L volumetric flask with reagent water.


7.8.10 Chromium solution, stock, 1 mL = 1000 µg Cr: Dissolve 1.923 g CrO3 (Cr fraction = 0.5200), weighed accurately to at least four significant figures, in 120 mL (1 + 5) HNO3. When solution is complete, dilute to volume in a 1 L volumetric flask with reagent water.


7.8.11 Cobalt solution, stock, 1 mL = 1000 µg Co: Dissolve 1.000 g Co metal, acid cleaned with (1 + 9) HNO3, weighed accurately to at least four significant figures, in 50.0 mL (1 + 1) HNO3. Let solution cool and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.12 Copper solution, stock, 1 mL = 1000 µg Cu: Dissolve 1.000 g Cu metal, acid cleaned with (1 + 9) HNO3, weighed accurately to at least four significant figures, in 50.0 mL (1 + 1) HNO3 with heating to effect dissolution. Let solution cool and dilute in a 1 L volumetric flask with reagent water.


7.8.13 Iron solution, stock, 1 mL = 1000 µg Fe: Dissolve 1.000 g Fe metal, acid cleaned with (1 + 1) HCl, weighed accurately to four significant figures, in 100 mL (1 + 1) HCl with heating to effect dissolution. Let solution cool and dilute with reagent water in a 1 L volumetric flask.


7.8.14 Lead solution, stock, 1 mL = 1000 µg Pb: Dissolve 1.599 g Pb(NO3)2 (Pb fraction = 0.6256), weighed accurately to at least four significant figures, in a minimum amount of (1 + 1) HNO3. Add 20.0 mL (1 + 1) HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.15 Lithium solution, stock, 1 mL = 1000 µg Li: Dissolve 5.324 g Li2CO3 (Li fraction = 0.1878), weighed accurately to at least four significant figures, in a minimum amount of (1 + 1) HCl and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.16 Magnesium solution, stock, 1 mL = 1000 µg Mg: Dissolve 1.000 g cleanly polished Mg ribbon, accurately weighed to at least four significant figures, in slowly added 5.0 mL (1 + 1) HCl (CAUTION: reaction is vigorous). Add 20.0 mL (1 + 1) HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.17 Manganese solution, stock, 1 mL = 1000 µg Mn: Dissolve 1.000 g of manganese metal, weighed accurately to at least four significant figures, in 50 mL (1 + 1) HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.18 Mercury solution, stock, 1 mL = 1000 µg Hg: DO NOT DRY. CAUTION: highly toxic element. Dissolve 1.354 g HgCl2 (Hg fraction = 0.7388) in reagent water. Add 50.0 mL concentrated HNO3 and dilute to volume in 1 L volumetric flask with reagent water.


7.8.19 Molybdenum solution, stock, 1 mL = 1000 µg Mo: Dissolve 1.500 g MoO3 (Mo fraction = 0.6666), weighed accurately to at least four significant figures, in a mixture of 100 mL reagent water and 10.0 mL concentrated NH4OH, heating to effect dissolution. Let solution cool and dilute with reagent water in a 1 L volumetric flask.


7.8.20 Nickel solution, stock, 1 mL = 1000 µg Ni: Dissolve 1.000 g of nickel metal, weighed accurately to at least four significant figures, in 20.0 mL hot concentrated HNO3, cool, and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.21 Phosphorus solution, stock, 1 mL = 1000 µg P: Dissolve 3.745 g NH4H2PO4 (P fraction = 0.2696), weighed accurately to at least four significant figures, in 200 mL reagent water and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.22 Potassium solution, stock, 1 mL = 1000 µg K: Dissolve 1.907 g KCl (K fraction = 0.5244) dried at 110 °C, weighed accurately to at least four significant figures, in reagent water, add 20 mL (1 + 1) HCl and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.23 Selenium solution, stock, 1 mL = 1000 µg Se: Dissolve 1.405 g SeO2 (Se fraction = 0.7116), weighed accurately to at least four significant figures, in 200 mL reagent water and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.24 Silica solution, stock, 1 mL = 1000 µg SiO2: DO NOT DRY. Dissolve 2.964 g (NH4)2SiF6, weighed accurately to at least four significant figures, in 200 mL (1 + 20) HCl with heating at 85 °C to effect dissolution. Let solution cool and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.25 Silver solution, stock, 1 mL = 1000 µg Ag: Dissolve 1.000 g Ag metal, weighed accurately to at least four significant figures, in 80 mL (1 + 1) HNO3 with heating to effect dissolution. Let solution cool and dilute with reagent water in a 1 L volumetric flask. Store solution in amber bottle or wrap bottle completely with aluminum foil to protect solution from light.


7.8.26 Sodium solution, stock, 1 mL = 1000 µg Na: Dissolve 2.542 g NaCl (Na fraction = 0.3934), weighed accurately to at least four significant figures, in reagent water. Add 10.0 mL concentrated HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.27 Strontium solution, stock, 1 mL = 1000 µg Sr: Dissolve 1.685 g SrCO3 (Sr fraction = 0.5935), weighed accurately to at least four significant figures, in 200 mL reagent water with dropwise addition of 100 mL (1 + 1) HCl. Dilute to volume in a 1 L volumetric flask with reagent water.


7.8.28 Thallium solution, stock, 1 mL = 1000 µg Tl: Dissolve 1.303 g TlNO3 (Tl fraction = 0.7672), weighed accurately to at least four significant figures, in reagent water. Add 10.0 mL concentrated HNO3 and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.29 Tin solution, stock, 1 mL = 1000 µg Sn: Dissolve 1.000 g Sn shot, weighed accurately to at least four significant figures, in an acid mixture of 10.0 mL concentrated HCl and 2.0 mL (1 + 1) HNO3 with heating to effect dissolution. Let solution cool, add 200 mL concentrated HCl, and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.30 Titanium solution, stock, 1 mL = 1000 µg Ti: DO NOT DRY. Dissolve 6.138 g (NH4)2TiO(C2O4)2•H2O (Ti fraction = 0.1629), weighed accurately to at least four significant figures, in 100 mL reagent water. Dilute to volume in a 1 L volumetric flask with reagent water.


7.8.31 Vanadium solution, stock, 1 mL = 1000 µg V: Dissolve 1.000 g V metal, acid cleaned with (1 + 9) HNO3, weighed accurately to at least four significant figures, in 50 mL (1 + 1) HNO3 with heating to effect dissolution. Let solution cool and dilute with reagent water to volume in a 1 L volumetric flask.


7.8.32 Yttrium solution, stock 1 mL = 1000 µg Y: Dissolve 1.270 g Y2O3 (Y fraction = 0.7875), weighed accurately to at least four significant figures, in 50 mL (1 + 1) HNO3, heating to effect dissolution. Cool and dilute to volume in a 1 L volumetric flask with reagent water.


7.8.33 Zinc solution, stock, 1 mL = 1000 µg Zn: Dissolve 1.000 g Zn metal, acid cleaned with (1 + 9) HNO3, weighed accurately to at least four significant figures, in 50 mL (1 + 1) HNO3 with heating to effect dissolution. Let solution cool and dilute with reagent water to volume in a 1 L volumetric flask.


7.9 Mixed Calibration Standard Solutions—For the analysis of total recoverable digested samples prepare mixed calibration standard solutions (see Table 3) by combining appropriate volumes of the stock solutions in 500 mL volumetric flasks containing 20 mL (1 + 1) HNO3 and 20 mL (1 + 1) HCl and dilute to volume with reagent water. Prior to preparing the mixed standards, each stock solution should be analyzed separately to determine possible spectral interferences or the presence of impurities. Care should be taken when preparing the mixed standards to ensure that the elements are compatible and stable together. To minimize the opportunity for contamination by the containers, it is recommended to transfer the mixed-standard solutions to acid-cleaned, never-used FEP fluorocarbon (FEP) bottles for storage. Fresh mixed standards should be prepared, as needed, with the realization that concentrations can change on aging. Calibration standards not prepared from primary standards must be initially verified using a certified reference solution. For the recommended wavelengths listed in Table 1 some typical calibration standard combinations are given in Table 3.


Note: If the addition of silver to the recommended mixed-acid calibration standard results in an initial precipitation, add 15 mL of reagent water and warm the flask until the solution clears. For this acid combination, the silver concentration should be limited to 0.5 mg/L.


7.10 Blanks—Four types of blanks are required for the analysis. The calibration blank is used in establishing the analytical curve, the laboratory reagent blank is used to assess possible contamination from the sample preparation procedure, the laboratory fortified blank is used to assess routine laboratory performance and a rinse blank is used to flush the instrument uptake system and nebulizer between standards, check solutions, and samples to reduce memory interferences.


7.10.1 The calibration blank for aqueous samples and extracts is prepared by acidifying reagent water to the same concentrations of the acids as used for the standards. The calibration blank should be stored in a FEP bottle.


7.10.2 The laboratory reagent blank (LRB) must contain all the reagents in the same volumes as used in the processing of the samples. The LRB must be carried through the same entire preparation scheme as the samples including sample digestion, when applicable.


7.10.3 The laboratory fortified blank (LFB) is prepared by fortifying an aliquot of the laboratory reagent blank with all analytes to a suitable concentration using the following recommended criteria: Ag 0.1 mg/L, K 5.0 mg/L and all other analytes 0.2 mg/L or a concentration approximately 100 times their respective MDL, whichever is greater. The LFB must be carried through the same entire preparation scheme as the samples including sample digestion, when applicable.


7.10.4 The rinse blank is prepared by acidifying reagent water to the same concentrations of acids as used in the calibration blank and stored in a convenient manner.


7.11 Instrument Performance Check (IPC) Solution—The IPC solution is used to periodically verify instrument performance during analysis. It should be prepared in the same acid mixture as the calibration standards by combining method analytes at appropriate concentrations. Silver must be limited to

7.12 Quality Control Sample (QCS)—Analysis of a QCS is required for initial and periodic verification of calibration standards or stock standard solutions in order to verify instrument performance. The QCS must be obtained from an outside source different from the standard stock solutions and prepared in the same acid mixture as the calibration standards. The concentration of the analytes in the QCS solution should be 1 mg/L, except silver, which must be limited to a concentration of 0.5 mg/L for solution stability. The QCS solution should be stored in a FEP bottle and analyzed as needed to meet data-quality needs. A fresh solution should be prepared quarterly or more frequently as needed.


7.13 Spectral Interference Check (SIC) Solutions—When interelement corrections are applied, SIC solutions are needed containing concentrations of the interfering elements at levels that will provide an adequate test of the correction factors.


7.13.1 SIC solutions containing (a) 300 mg/L Fe; (b) 200 mg/L AL; (c) 50 mg/L Ba; (d) 50 mg/L Be; (e) 50 mg/L Cd; (f) 50 mg/L Ce; (g) 50 mg/L Co; (h) 50 mg/L Cr; (i) 50 mg/L Cu; (j) 50 mg/L Mn; (k) 50 mg/L Mo; (l) 50 mg/L Ni; (m) 50 mg/L Sn; (n) 50 mg/L SiO2; (o) 50 mg/L Ti; (p) 50 mg/L Tl and (q) 50 mg/L V should be prepared in the same acid mixture as the calibration standards and stored in FEP bottles. These solutions can be used to periodically verify a partial list of the on-line (and possible off-line) interelement spectral correction factors for the recommended wavelengths given in Table 1. Other solutions could achieve the same objective as well. (Multielement SIC solutions
3 may be prepared and substituted for the single element solutions provided an analyte is not subject to interference from more than one interferant in the solution.)


Note: If wavelengths other than those recommended in Table 1 are used, other solutions different from those above (a through q) may be required.


7.13.2 For interferences from iron and aluminum, only those correction factors (positive or negative) when multiplied by 100 to calculate apparent analyte concentrations that exceed the determined analyte IDL or fall below the lower 3-sigma control limit of the calibration blank need be tested on a daily basis.


7.13.3 For the other interfering elements, only those correction factors (positive or negative) when multiplied by 10 to calculate apparent analyte concentrations that exceed the determined analyte IDL or fall below the lower 3-sigma control limit of the calibration blank need be tested on a daily basis.


7.13.4 If the correction routine is operating properly, the determined apparent analyte(s) concentration from analysis of each interference solution (a through q) should fall within a specific concentration range bracketing the calibration blank. This concentration range is calculated by multiplying the concentration of the interfering element by the value of the correction factor being tested and dividing by 10. If after subtraction of the calibration blank the apparent analyte concentration is outside (above or below) this range, a change in the correction factor of more than 10% should be suspected. The cause of the change should be determined and corrected and the correction factor should be updated.


Note: The SIC solution should be analyzed more than once to confirm a change has occurred with adequate rinse time between solutions and before subsequent analysis of the calibration blank.


7.13.5 If the correction factors tested on a daily basis are found to be within the 10% criteria for five consecutive days, the required verification frequency of those factors in compliance may be extended to a weekly basis. Also, if the nature of the samples analyzed is such (e.g., finished drinking water) that they do not contain concentrations of the interfering elements at the 10 mg/L level, daily verification is not required; however, all interelement spectral correction factors must be verified annually and updated, if necessary.


7.13.6 If the instrument does not display negative concentration values, fortify the SIC solutions with the elements of interest at 1 mg/L and test for analyte recoveries that are below 95%. In the absence of measurable analyte, over-correction could go undetected because a negative value could be reported as zero.


7.14 For instruments without interelement correction capability or when interelement corrections are not used, SIC solutions (containing similar concentrations of the major components in the samples, e.g., 10 mg/L) can serve to verify the absence of effects at the wavelengths selected. These data must be kept on file with the sample analysis data. If the SIC solution confirms an operative interference that is 10% of the analyte concentration, the analyte must be determined using a wavelength and background correction location free of the interference or by another approved test procedure. Users are advised that high salt concentrations can cause analyte signal suppressions and confuse interference tests.


7.15 Plasma Solution—The plasma solution is used for determining the optimum viewing height of the plasma above the work coil prior to using the method (Section 10.2). The solution is prepared by adding a 5 mL aliquot from each of the stock standard solutions of arsenic, lead, selenium, and thallium to a mixture of 20 mL (1 + 1) nitric acid and 20 mL (1 + 1) hydrochloric acid and diluting to 500 mL with reagent water. Store in a FEP bottle.


8.0 Sample Collection, Preservation, and Storage

8.1 Prior to the collection of an aqueous sample, consideration should be given to the type of data required, (i.e., dissolved or total recoverable), so that appropriate preservation and pretreatment steps can be taken. The pH of all aqueous samples must be tested immediately prior to aliquoting for processing or “direct analysis” to ensure the sample has been properly preserved. If properly acid preserved, the sample can be held up to six months before analysis.


8.2 For the determination of the dissolved elements, the sample must be filtered through a 0.45 µm pore diameter membrane filter at the time of collection or as soon thereafter as practically possible. (Glass or plastic filtering apparatus are recommended to avoid possible contamination. Only plastic apparatus should be used when the determinations of boron and silica are critical.) Use a portion of the filtered sample to rinse the filter flask, discard this portion and collect the required volume of filtrate. Acidify the filtrate with (1 + 1) nitric acid immediately following filtration to pH

8.3 For the determination of total recoverable elements in aqueous samples, samples are not filtered, but acidified with (1 + 1) nitric acid to pH 2, more acid must be added and the sample held for 16 hours until verified to be pH

Note: When the nature of the sample is either unknown or is known to be hazardous, acidification should be done in a fume hood. See Section 5.2.


8.4 Solid samples require no preservation prior to analysis other than storage at 4 °C. There is no established holding time limitation for solid samples.


8.5 For aqueous samples, a field blank should be prepared and analyzed as required by the data user. Use the same container and acid as used in sample collection.


9.0 Quality Control

9.1 Each laboratory using this method is required to operate a formal quality control (QC) program. The minimum requirements of this program consist of an initial demonstration of laboratory capability, and the periodic analysis of laboratory reagent blanks, fortified blanks and other laboratory solutions as a continuing check on performance. The laboratory is required to maintain performance records that define the quality of the data thus generated.


9.2 Initial Demonstration of Performance (mandatory).


9.2.1 The initial demonstration of performance is used to characterize instrument performance (determination of linear dynamic ranges and analysis of quality control samples) and laboratory performance (determination of method detection limits) prior to analyses conducted by this method.


9.2.2 Linear dynamic range (LDR)—The upper limit of the LDR must be established for each wavelength utilized. It must be determined from a linear calibration prepared in the normal manner using the established analytical operating procedure for the instrument. The LDR should be determined by analyzing succeedingly higher standard concentrations of the analyte until the observed analyte concentration is no more than 10% below the stated concentration of the standard. Determined LDRs must be documented and kept on file. The LDR which may be used for the analysis of samples should be judged by the analyst from the resulting data. Determined sample analyte concentrations that are greater than 90% of the determined upper LDR limit must be diluted and reanalyzed. The LDRs should be verified annually or whenever, in the judgment of the analyst, a change in analytical performance caused by either a change in instrument hardware or operating conditions would dictate they be redetermined.


9.2.3 Quality control sample (QCS)—When beginning the use of this method, on a quarterly basis, after the preparation of stock or calibration standard solutions or as required to meet data-quality needs, verify the calibration standards and acceptable instrument performance with the preparation and analyses of a QCS (Section 7.12). To verify the calibration standards the determined mean concentrations from three analyses of the QCS must be within 5% of the stated values. If the calibration standard cannot be verified, performance of the determinative step of the method is unacceptable. The source of the problem must be identified and corrected before either proceeding on with the initial determination of method detection limits or continuing with on-going analyses.


9.2.4 Method detection limit (MDL)—MDLs must be established for all wavelengths utilized, using reagent water (blank) fortified at a concentration of two to three times the estimated instrument detection limit.
15 To determine MDL values, take seven replicate aliquots of the fortified reagent water and process through the entire analytical method. Perform all calculations defined in the method and report the concentration values in the appropriate units. Calculate the MDL as follows:


MDL = (t) × (S)

where:

t = students’ t value for a 99% confidence level and a standard deviation estimate with n-1 degrees of freedom [t = 3.14 for seven replicates]

S = standard deviation of the replicate analyses

Note: If additional confirmation is desired, reanalyze the seven replicate aliquots on two more nonconsecutive days and again calculate the MDL values for each day. An average of the three MDL values for each analyte may provide for a more appropriate MDL estimate. If the relative standard deviation (RSD) from the analyses of the seven aliquots is

The MDLs must be sufficient to detect analytes at the required levels according to compliance monitoring regulation (Section 1.2). MDLs should be determined annually, when a new operator begins work or whenever, in the judgment of the analyst, a change in analytical performance caused by either a change in instrument hardware or operating conditions would dictate they be redetermined.


9.3 Assessing Laboratory Performance (mandatory)


9.3.1 Laboratory reagent blank (LRB)—The laboratory must analyze at least one LRB (Section 7.10.2) with each batch of 20 or fewer samples of the same matrix. LRB data are used to assess contamination from the laboratory environment. LRB values that exceed the MDL indicate laboratory or reagent contamination should be suspected. When LRB values constitute 10% or more of the analyte level determined for a sample or is 2.2 times the analyte MDL whichever is greater, fresh aliquots of the samples must be prepared and analyzed again for the affected analytes after the source of contamination has been corrected and acceptable LRB values have been obtained.


9.3.2 Laboratory fortified blank (LFB)—The laboratory must analyze at least one LFB (Section 7.10.3) with each batch of samples. Calculate accuracy as percent recovery using the following equation:



where:

R = percent recovery

LFB = laboratory fortified blank

LRB = laboratory reagent blank

s = concentration equivalent of analyte added to fortify the LBR solution

If the recovery of any analyte falls outside the required control limits of 85-115%, that analyte is judged out of control, and the source of the problem should be identified and resolved before continuing analyses.


9.3.3 The laboratory must use LFB analyses data to assess laboratory performance against the required control limits of 85-115% (Section 9.3.2). When sufficient internal performance data become available (usually a minimum of 20-30 analyses), optional control limits can be developed from the mean percent recovery (x) and the standard deviation (S) of the mean percent recovery. These data can be used to establish the upper and lower control limits as follows:


UPPER CONTROL LIMIT = x + 3S

LOWER CONTROL LIMIT = x − 3S

The optional control limits must be equal to or better than the required control limits of 85-115%. After each five to 10 new recovery measurements, new control limits can be calculated using only the most recent 20-30 data points. Also, the standard deviation (S) data should be used to establish an on-going precision statement for the level of concentrations included in the LFB. These data must be kept on file and be available for review.


9.3.4 Instrument performance check (IPC) solution—For all determinations the laboratory must analyze the IPC solution (Section 7.11) and a calibration blank immediately following daily calibration, after every 10th sample (or more frequently, if required) and at the end of the sample run. Analysis of the calibration blank should always be

9.3.5 Spectral interference check (SIC) solution—For all determinations the laboratory must periodically verify the interelement spectral interference correction routine by analyzing SIC solutions. The preparation and required periodic analysis of SIC solutions and test criteria for verifying the interelement interference correction routine are given in Section 7.13. Special cases where on-going verification is required are described in Section 7.14.


9.4 Assessing Analyte Recovery and Data Quality.


9.4.1 Sample homogeneity and the chemical nature of the sample matrix can affect analyte recovery and the quality of the data. Taking separate aliquots from the sample for replicate and fortified analyses can in some cases assess the effect. Unless otherwise specified by the data user, laboratory or program, the following laboratory fortified matrix (LFM) procedure (Section 9.4.2) is required. Also, other tests such as the analyte addition test (Section 9.5.1) and sample dilution test (Section 9.5.2) can indicate if matrix effects are operative.


9.4.2 The laboratory must add a known amount of each analyte to a minimum of 10% of the routine samples. In each case the LFM aliquot must be a duplicate of the aliquot used for sample analysis and for total recoverable determinations added prior to sample preparation. For water samples, the added analyte concentration must be the same as that used in the laboratory fortified blank (Section 7.10.3). For solid samples, however, the concentration added should be expressed as mg/kg and is calculated for a one gram aliquot by multiplying the added analyte concentration (mg/L) in solution by the conversion factor 100 (mg/L × 0.1L/0.001kg = 100, Section 12.5). (For notes on Ag, Ba, and Sn see Sections 1.7 and 1.8.) Over time, samples from all routine sample sources should be fortified.


Note: The concentration of calcium, magnesium, sodium and strontium in environmental waters, along with iron and aluminum in solids can vary greatly and are not necessarily predictable. Fortifying these analytes in routine samples at the same concentration used for the LFB may prove to be of little use in assessing data quality for these analytes. For these analytes sample dilution and reanalysis using the criteria given in Section 9.5.2 is recommended. Also, if specified by the data user, laboratory or program, samples can be fortified at higher concentrations, but even major constituents should be limited to

9.4.3 Calculate the percent recovery for each analyte, corrected for background concentrations measured in the unfortified sample, and compare these values to the designated LFM recovery range of 70-130% or a 3-sigma recovery range calculated from the regression equations given in Table 9.
16 Recovery calculations are not required if the concentration added is less than 30% of the sample background concentration. Percent recovery may be calculated in units appropriate to the matrix, using the following equation:



where:

R = percent recovery

Cs = fortified sample concentration

C = sample background concentration

s = concentration equivalent of analyte added to fortify the sample

9.4.4 If the recovery of any analyte falls outside the designated LFM recovery range, and the laboratory performance for that analyte is shown to be in control (Section 9.3), the recovery problem encountered with the fortified sample is judged to be matrix related, not system related. The data user should be informed that the result for that analyte in the unfortified sample is suspect due to either the heterogeneous nature of the sample or matrix effects and analysis by method of standard addition or the use of an internal standard(s) (Section 11.5) should be considered.


9.4.5 Where reference materials are available, they should be analyzed to provide additional performance data. The analysis of reference samples is a valuable tool for demonstrating the ability to perform the method acceptably. Reference materials containing high concentrations of analytes can provide additional information on the performance of the spectral interference correction routine.


9.5 Assess the possible need for the method of standard additions (MSA) or internal standard elements by the following tests. Directions for using MSA or internal standard(s) are given in Section 11.5.


9.5.1 Analyte addition test: An analyte(s) standard added to a portion of a prepared sample, or its dilution, should be recovered to within 85% to 115% of the known value. The analyte(s) addition should produce a minimum level of 20 times and a maximum of 100 times the method detection limit. If the analyte addition is

9.5.2 Dilution test: If the analyte concentration is sufficiently high (minimally, a factor of 50 above the instrument detection limit in the original solution but
10.0 Calibration and Standardization

10.1 Specific wavelengths are listed in Table 1. Other wavelengths may be substituted if they can provide the needed sensitivity and are corrected for spectral interference. However, because of the difference among various makes and models of spectrometers, specific instrument operating conditions cannot be given. The instrument and operating conditions utilized for determination must be capable of providing data of acceptable quality to the program and data user. The analyst should follow the instructions provided by the instrument manufacturer unless other conditions provide similar or better performance for a task. Operating conditions for aqueous solutions usually vary from 1100-1200 watts forward power, 15-16 mm viewing height, 15-19 L/min. argon coolant flow, 0.6-1 L/min. argon aerosol flow, 1-1.8 mL/min. sample pumping rate with a one minute preflush time and measurement time near 1 s per wavelength peak (for sequential instruments) and near 10 s per sample (for simultaneous instruments). Use of the Cu/Mn intensity ratio at 324.754 nm and 257.610 nm (by adjusting the argon aerosol flow) has been recommended as a way to achieve repeatable interference correction factors.
17


10.2 Prior to using this method optimize the plasma operating conditions. The following procedure is recommended for vertically configured plasmas. The purpose of plasma optimization is to provide a maximum signal-to-background ratio for the least sensitive element in the analytical array. The use of a mass flow controller to regulate the nebulizer gas flow rate greatly facilitates the procedure.


10.2.1 Ignite the plasma and select an appropriate incident rf power with minimum reflected power. Allow the instrument to become thermally stable before beginning. This usually requires at least 30 to 60 minutes of operation. While aspirating the 1000 µg/mL solution of yttrium (Section 7.8.32), follow the instrument manufacturer’s instructions and adjust the aerosol carrier gas flow rate through the nebulizer so a definitive blue emission region of the plasma extends approximately from 5-20 mm above the top of the work coil.
18 Record the nebulizer gas flow rate or pressure setting for future reference.


10.2.2 After establishing the nebulizer gas flow rate, determine the solution uptake rate of the nebulizer in mL/min. by aspirating a known volume calibration blank for a period of at least three minutes. Divide the spent volume by the aspiration time (in minutes) and record the uptake rate. Set the peristaltic pump to deliver the uptake rate in a steady even flow.


10.2.3 After horizontally aligning the plasma and/or optically profiling the spectrometer, use the selected instrument conditions from Sections 10.2.1 and 10.2.2, and aspirate the plasma solution (Section 7.15), containing 10 µg/mL each of As, Pb, Se and Tl. Collect intensity data at the wavelength peak for each analyte at 1 mm intervals from 14-18 mm above the top of the work coil. (This region of the plasma is commonly referred to as the analytical zone.)
19 Repeat the process using the calibration blank. Determine the net signal to blank intensity ratio for each analyte for each viewing height setting. Choose the height for viewing the plasma that provides the largest intensity ratio for the least sensitive element of the four analytes. If more than one position provides the same ratio, select the position that provides the highest net intensity counts for the least sensitive element or accept a compromise position of the intensity ratios of all four analytes.


10.2.4 The instrument operating condition finally selected as being optimum should provide the lowest reliable instrument detection limits and method detection limits. Refer to Tables 1 and 4 for comparison of IDLs and MDLs, respectively.


10.2.5 If either the instrument operating conditions, such as incident power and/or nebulizer gas flow rate are changed, or a new torch injector tube having a different orifice i.d. is installed, the plasma and plasma viewing height should be reoptimized.


10.2.6 Before daily calibration and after the instrument warmup period, the nebulizer gas flow must be reset to the determined optimized flow. If a mass flow controller is being used, it should be reset to the recorded optimized flow rate. In order to maintain valid spectral interelement correction routines the nebulizer gas flow rate should be the same from day-to-day (

10.3 Before using the procedure (Section 11.0) to analyze samples, there must be data available documenting initial demonstration of performance. The required data and procedure is described in Section 9.2. This data must be generated using the same instrument operating conditions and calibration routine (Section 11.4) to be used for sample analysis. These documented data must be kept on file and be available for review by the data user.


10.4 After completing the initial demonstration of performance, but before analyzing samples, the laboratory must establish and initially verify an interelement spectral interference correction routine to be used during sample analysis. A general description concerning spectral interference and the analytical requirements for background correction and for correction of interelement spectral interference in particular are given in Section 4.1. To determine the appropriate location for background correction and to establish the interelement interference correction routine, repeated spectral scan about the analyte wavelength and repeated analyses of the single element solutions may be required. Criteria for determining an interelement spectral interference is an apparent positive or negative concentration on the analyte that is outside the 3-sigma control limits of the calibration blank for the analyte. (The upper-control limit is the analyte IDL.) Once established, the entire routine must be initially and periodically verified annually, or whenever there is a change in instrument operating conditions (Section 10.2.5). Only a portion of the correction routine must be verified more frequently or on a daily basis. Test criteria and required solutions are described in Section 7.13. Initial and periodic verification data of the routine should be kept on file. Special cases where on-going verification are required is described in Section 7.14.


11.0 Procedure

11.1 Aqueous Sample Preparation—Dissolved Analytes

11.1.1 For the determination of dissolved analytes in ground and surface waters, pipet an aliquot (20 mL) of the filtered, acid preserved sample into a 50 mL polypropylene centrifuge tube. Add an appropriate volume of (1 + 1) nitric acid to adjust the acid concentration of the aliquot to approximate a 1% (v/v) nitric acid solution (e.g., add 0.4 mL (1 + 1) HNO3 to a 20 mL aliquot of sample). Cap the tube and mix. The sample is now ready for analysis (Section 1.3). Allowance for sample dilution should be made in the calculations. (If mercury is to be determined, a separate aliquot must be additionally acidified to contain 1% (v/v) HCl to match the signal response of mercury in the calibration standard and reduce memory interference effects. Section 1.9).



Note:

If a precipitate is formed during acidification, transport, or storage, the sample aliquot must be treated using the procedure described in Sections 11.2.2 through 11.2.7 prior to analysis.


11.2 Aqueous Sample Preparation—Total Recoverable Analytes

11.2.1 For the “direct analysis” of total recoverable analytes in drinking water samples containing turbidity

11.2.2 For the determination of total recoverable analytes in aqueous samples (other than drinking water with

Note:

If the sample contains undissolved solids >1%, a well mixed, acid preserved aliquot containing no more than 1 g particulate material should be cautiously evaporated to near 10 mL and extracted using the acid-mixture procedure described in Sections 11.3.3 through 11.3.6.


11.2.3 Add 2 mL (1 + 1) nitric acid and 1.0 mL of (1 + 1) hydrochloric acid to the beaker containing the measured volume of sample. Place the beaker on the hot plate for solution evaporation. The hot plate should be located in a fume hood and previously adjusted to provide evaporation at a temperature of approximately but no higher than 85 °C. (See the following note.) The beaker should be covered with an elevated watch glass or other necessary steps should be taken to prevent sample contamination from the fume hood environment.



Note:

For proper heating adjust the temperature control of the hot plate such that an uncovered Griffin beaker containing 50 mL of water placed in the center of the hot plate can be maintained at a temperature approximately but no higher than 85 °C. (Once the beaker is covered with a watch glass the temperature of the water will rise to approximately 95 °C.)


11.2.4 Reduce the volume of the sample aliquot to about 20 mL by gentle heating at 85 °C. DO NOT BOIL. This step takes about two hours for a 100 mL aliquot with the rate of evaporation rapidly increasing as the sample volume approaches 20 mL. (A spare beaker containing 20 mL of water can be used as a gauge.)


11.2.5 Cover the lip of the beaker with a watch glass to reduce additional evaporation and gently reflux the sample for 30 minutes. (Slight boiling may occur, but vigorous boiling must be avoided to prevent loss of the HCl-H2O azeotrope.)


11.2.6 Allow the beaker to cool. Quantitatively transfer the sample solution to a 50 mL volumetric flask, make to volume with reagent water, stopper and mix.


11.2.7 Allow any undissolved material to settle overnight, or centrifuge a portion of the prepared sample until clear. (If after centrifuging or standing overnight the sample contains suspended solids that would clog the nebulizer, a portion of the sample may be filtered for their removal prior to analysis. However, care should be exercised to avoid potential contamination from filtration.) The sample is now ready for analysis. Because the effects of various matrices on the stability of diluted samples cannot be characterized, all analyses should be performed as soon as possible after the completed preparation.


11.3 Solid Sample Preparation—Total Recoverable Analytes

11.3.1 For the determination of total recoverable analytes in solid samples, mix the sample thoroughly and transfer a portion (>20 g) to tared weighing dish, weigh the sample and record the wet weight (WW). (For samples with 35% a larger aliquot 50-100 g is required.) Dry the sample to a constant weight at 60 °C and record the dry weight (DW) for calculation of percent solids (Section 12.6). (The sample is dried at 60 °C to prevent the loss of mercury and other possible volatile metallic compounds, to facilitate sieving, and to ready the sample for grinding.)


11.3.2 To achieve homogeneity, sieve the dried sample using a 5-mesh polypropylene sieve and grind in a mortar and pestle. (The sieve, mortar and pestle should be cleaned between samples.) From the dried, ground material weigh accurately a representative 1.0 ±0.01 g aliquot (W) of the sample and transfer to a 250 mL Phillips beaker for acid extraction (Sections 1.6, 1.7, 1.8, and 1.9).


11.3.3 To the beaker add 4 mL of (1 + 1) HNO3 and 10 mL of (1 + 4) HCl. Cover the lip of the beaker with a watch glass. Place the beaker on a hot plate for reflux extraction of the analytes. The hot plate should be located in a fume hood and previously adjusted to provide a reflux temperature of approximately 95 °C. (See the following note.)



Note:

For proper heating adjust the temperature control of the hot plate such that an uncovered Griffin beaker containing 50 mL of water placed in the center of the hot plate can be maintained at a temperature approximately but no higher than 85 °C. (Once the beaker is covered with a watch glass the temperature of the water will rise to approximately 95 °C.) Also, a block digester capable of maintaining a temperature of 95 °C and equipped with 250 mL constricted volumetric digestion tubes may be substituted for the hot plate and conical beakers in the extraction step.


11.3.4 Heat the sample and gently reflux for 30 minutes. Very slight boiling may occur, however vigorous boiling must be avoided to prevent loss of the HCl-H2O azeotrope. Some solution evaporation will occur (3-4 mL).


11.3.5 Allow the sample to cool and quantitatively transfer the extract to a 100 mL volumetric flask. Dilute to volume with reagent water, stopper and mix.


11.3.6 Allow the sample extract solution to stand overnight to separate insoluble material or centrifuge a portion of the sample solution until clear. (If after centrifuging or standing overnight the extract solution contains suspended solids that would clog the nebulizer, a portion of the extract solution may be filtered for their removal prior to analysis. However, care should be exercised to avoid potential contamination from filtration.) The sample extract is now ready for analysis. Because the effects of various matrices on the stability of diluted samples cannot be characterized, all analyses should be performed as soon as possible after the completed preparation.


11.4 Sample Analysis

11.4.1 Prior to daily calibration of the instrument inspect the sample introduction system including the nebulizer, torch, injector tube and uptake tubing for salt deposits, dirt and debris that would restrict solution flow and affect instrument performance. Clean the system when needed or on a daily basis.


11.4.2 Configure the instrument system to the selected power and operating conditions as determined in Sections 10.1 and 10.2.


11.4.3 The instrument must be allowed to become thermally stable before calibration and analyses. This usually requires at least 30 to 60 minutes of operation. After instrument warmup, complete any required optical profiling or alignment particular to the instrument.


11.4.4 For initial and daily operation calibrate the instrument according to the instrument manufacturer’s recommended procedures, using mixed calibration standard solutions (Section 7.9) and the calibration blank (Section 7.10.1). A peristaltic pump must be used to introduce all solutions to the nebulizer. To allow equilibrium to be reached in the plasma, aspirate all solutions for 30 seconds after reaching the plasma before beginning integration of the background corrected signal to accumulate data. When possible, use the average value of replicate integration periods of the signal to be correlated to the analyte concentration. Flush the system with the rinse blank (Section 7.10.4) for a minimum of 60 seconds (Section 4.4) between each standard. The calibration line should consist of a minimum of a calibration blank and a high standard. Replicates of the blank and highest standard provide an optimal distribution of calibration standards to minimize the confidence band for a straight-line calibration in a response region with uniform variance.
20


11.4.5 After completion of the initial requirements of this method (Sections 10.3 and 10.4), samples should be analyzed in the same operational manner used in the calibration routine with the rinse blank also being used between all sample solutions, LFBs, LFMs, and check solutions (Section 7.10.4).


11.4.6 During the analysis of samples, the laboratory must comply with the required quality control described in Sections 9.3 and 9.4. Only for the determination of dissolved analytes or the “direct analysis” of drinking water with turbidity of

11.4.7 Determined sample analyte concentrations that are 90% or more of the upper limit of the analyte LDR must be diluted with reagent water that has been acidified in the same manner as calibration blank and reanalyzed (see Section 11.4.8). Also, for the interelement spectral interference correction routines to remain valid during sample analysis, the interferant concentration must not exceed its LDR. If the interferant LDR is exceeded, sample dilution with acidified reagent water and reanalysis is required. In these circumstances analyte detection limits are raised and determination by another approved test procedure that is either more sensitive and/or interference free is recommended.


11.4.8 When it is necessary to assess an operative matrix interference (e.g., signal reduction due to high dissolved solids), the tests described in Section 9.5 are recommended.


11.4.9 Report data as directed in Section 12.0.


11.5 If the method of standard additions (MSA) is used, standards are added at one or more levels to portions of a prepared sample. This technique
21 compensates for enhancement or depression of an analyte signal by a matrix. It will not correct for additive interferences such as contamination, interelement interferences, or baseline shifts. This technique is valid in the linear range when the interference effect is constant over the range, the added analyte responds the same as the endogenous analyte, and the signal is corrected for additive interferences. The simplest version of this technique is the single-addition method. This procedure calls for two identical aliquots of the sample solution to be taken. To the first aliquot, a small volume of standard is added; while to the second aliquot, a volume of acid blank is added equal to the standard addition. The sample concentration is calculated by the following:



where:

C = Concentration of the standard solution (mg/L)

S1 = Signal for fortified aliquot

S2 = Signal for unfortified aliquot

V1 = Volume of the standard addition (L)

V2 = Volume of the sample aliquot (L) used for MSA

For more than one fortified portion of the prepared sample, linear regression analysis can be applied using a computer or calculator program to obtain the concentration of the sample solution. An alternative to using the method of standard additions is use of the internal standard technique by adding one or more elements (not in the samples and verified not to cause an uncorrected interelement spectral interference) at the same concentration (which is sufficient for optimum precision) to the prepared samples (blanks and standards) that are affected the same as the analytes by the sample matrix. Use the ratio of analyte signal to the internal standard signal for calibration and quantitation.


12.0 Data Analysis and Calculations

12.1 Sample data should be reported in units of mg/L for aqueous samples and mg/kg dry weight for solid samples.


12.2 For dissolved aqueous analytes (Section 11.1) report the data generated directly from the instrument with allowance for sample dilution. Do not report analyte concentrations below the IDL.


12.3 For total recoverable aqueous analytes (Section 11.2), multiply solution analyte concentrations by the dilution factor 0.5, when 100 mL aliquot is used to produce the 50 mL final solution, and report data as instructed in Section 12.4. If a different aliquot volume other than 100 mL is used for sample preparation, adjust the dilution factor accordingly. Also, account for any additional dilution of the prepared sample solution needed to complete the determination of analytes exceeding 90% or more of the LDR upper limit. Do not report data below the determined analyte MDL concentration or below an adjusted detection limit reflecting smaller sample aliquots used in processing or additional dilutions required to complete the analysis.


12.4 For analytes with MDLs

12.5 For total recoverable analytes in solid samples (Section 11.3), round the solution analyte concentrations (mg/L) as instructed in Section 12.4. Report the data up to three significant figures as mg/kg dry-weight basis unless specified otherwise by the program or data user. Calculate the concentration using the equation below:



where:

C = Concentration in extract (mg/L)

V = Volume of extract (L, 100 mL = 0.1L)

D = Dilution factor (undiluted = 1)

W = Weight of sample aliquot extracted (g × 0.001 = kg)

Do not report analyte data below the estimated solids MDL or an adjusted MDL because of additional dilutions required to complete the analysis.


12.6 To report percent solids in solid samples (Section 11.3) calculate as follows:



where:

DW = Sample weight (g) dried at 60 ºC

WW = Sample weight (g) before drying

Note: If the data user, program or laboratory requires that the reported percent solids be determined by drying at 105 °C, repeat the procedure given in Section 11.3 using a separate portion (>20 g) of the sample and dry to constant weight at 103-105 °C.


12.7 The QC data obtained during the analyses provide an indication of the quality of the sample data and should be provided with the sample results.


13.0 Method Performance

13.1 Listed in Table 4 are typical single laboratory total recoverable MDLs determined for the recommended wavelengths using simultaneous ICP-AES and the operating conditions given in Table 5. The MDLs were determined in reagent blank matrix (best case situation). PTFE beakers were used to avoid boron and silica contamination from glassware with the final dilution to 50 mL completed in polypropylene centrifuged tubes. The listed MDLs for solids are estimates and were calculated from the aqueous MDL determinations.


13.2 Data obtained from single laboratory method testing are summarized in Table 6 for five types of water samples consisting of drinking water, surface water, ground water, and two wastewater effluents. The data presented cover all analytes except cerium and titanium. Samples were prepared using the procedure described in Section 11.2. For each matrix, five replicate aliquots were prepared, analyzed and the average of the five determinations used to define the sample background concentration of each analyte. In addition, two pairs of duplicates were fortified at different concentration levels. For each method analyte, the sample background concentration, mean percent recovery, standard deviation of the percent recovery, and relative percent difference between the duplicate fortified samples are listed in Table 6. The variance of the five replicate sample background determinations is included in the calculated standard deviation of the percent recovery when the analyte concentration in the sample was greater than the MDL. The tap and well waters were processed in Teflon and quartz beakers and diluted in polypropylene centrifuged tubes. The nonuse of borosilicate glassware is reflected in the precision and recovery data for boron and silica in those two sample types.


13.3 Data obtained from single laboratory method testing are summarized in Table 7 for three solid samples consisting of EPA 884 Hazardous Soil, SRM 1645 River Sediment, and EPA 286 Electroplating Sludge. Samples were prepared using the procedure described in Section 11.3. For each method analyte, the sample background concentration, mean percent recovery of the fortified additions, the standard deviation of the percent recovery, and relative percent difference between duplicate additions were determined as described in Section 13.2. Data presented are for all analytes except cerium, silica, and titanium. Limited comparative data to other methods and SRM materials are presented in Reference 23 of Section 16.0.


13.4 Performance data for aqueous solutions independent of sample preparation from a multilaboratory study are provided in Table 8.
22


13.5 Listed in Table 9 are regression equations for precision and bias for 25 analytes abstracted from EPA Method Study 27, a multilaboratory validation study of Method 200.7.
1 These equations were developed from data received from 12 laboratories using the total recoverable sample preparation procedure on reagent water, drinking water, surface water and three industrial effluents. For a complete review and description of the study, see Reference 16 of Section 16.0.


14.0 Pollution Prevention

14.1 Pollution prevention encompasses any technique that reduces or eliminates the quantity or toxicity of waste at the point of generation. Numerous opportunities for pollution prevention exist in laboratory operation. The EPA has established a preferred hierarchy of environmental management techniques that places pollution prevention as the management option of first choice. Whenever feasible, laboratory personnel should use pollution prevention techniques to address their waste generation (e.g., Section 7.8). When wastes cannot be feasibly reduced at the source, the Agency recommends recycling as the next best option.


14.2 For information about pollution prevention that may be applicable to laboratories and research institutions, consult “Less is Better: Laboratory Chemical Management for Waste Reduction”, available from the American Chemical Society’s Department of Government Relations and Science Policy, 1155 16th Street NW., Washington, DC 20036, (202) 872-4477.


15.0 Waste Management

15.1 The Environmental Protection Agency requires that laboratory waste management practices be conducted consistent with all applicable rules and regulations. The Agency urges laboratories to protect the air, water, and land by minimizing and controlling all releases from hoods and bench operations, complying with the letter and spirit of any sewer discharge permits and regulations, and by complying with all solid and hazardous waste regulations, particularly the hazardous waste identification rules and land disposal restrictions. For further information on waste management consult “The Waste Management Manual for Laboratory Personnel”, available from the American Chemical Society at the address listed in the Section 14.2.


16.0 References

1. U.S. Environmental Protection Agency. Inductively Coupled Plasma—Atomic Emission Spectrometric Method for Trace Element Analysis of Water and Wastes—Method 200.7, Dec. 1982. EPA-600/4-79-020, revised March 1983.

2. U.S. Environmental Protection Agency. Inductively Coupled Plasma Atomic Emission Spectroscopy Method 6010, SW-846 Test Methods for Evaluating Solid Waste, 3rd Edition, 1986.

3. U.S. Environmental Protection Agency. Method 200.7: Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma—Atomic Emission Spectrometry, revision 3.3, EPA 600 4-91/010, June 1991.

4. U.S. Environmental Protection Agency. Inductively Coupled Plasma—Atomic Emission Spectrometry Method for the Analysis of Waters and Solids, EMMC, July 1992.

5. Fassel, V.A. et al. Simultaneous Determination of Wear Metals in Lubricating Oils by Inductively-Coupled Plasma Atomic Emission Spectrometry. Anal. Chem. 48:516-519, 1976.

6. Merryfield, R.N. and R.C. Loyd. Simultaneous Determination of Metals in Oil by Inductively Coupled Plasma Emission Spectrometry. Anal. Chem. 51:1965-1968, 1979.

7. Winge, R.K. et al. Inductively Coupled Plasma—Atomic Emission Spectroscopy: An Atlas of Spectral Information, Physical Science Data 20. Elsevier Science Publishing, New York, New York, 1985.

8. Boumans, P.W.J.M. Line Coincidence Tables for Inductively Coupled Plasma Atomic Emission Spectrometry, 2nd edition. Pergamon Press, Oxford, United Kingdom, 1984.

9. Carcinogens—Working With Carcinogens, Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, Aug. 1977. Available from the National Technical Information Service (NTIS) as PB-277256.

10. OSHA Safety and Health Standards, General Industry, (29 CFR 1910), Occupational Safety and Health Administration, OSHA 2206, (Revised, January 1976).

11. Safety in Academic Chemistry Laboratories, American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

12. Proposed OSHA Safety and Health Standards, Laboratories, Occupational Safety and Health Administration, Federal Register, July 24, 1986.

13. Rohrbough, W.G. et al. Reagent Chemicals, American Chemical Society Specifications, 7th edition. American Chemical Society, Washington, DC, 1986.

14. American Society for Testing and Materials. Standard Specification for Reagent Water, D1193-77. Annual Book of ASTM Standards, Vol. 11.01. Philadelphia, PA, 1991.

15. Code of Federal Regulations 40, Ch. 1, Pt. 136 Appendix B.

16. Maxfield, R. and B. Mindak. EPA Method Study 27, Method 200.7 Trace Metals by ICP, Nov. 1983. Available from National Technical Information Service (NTIS) as PB 85-248-656.

17. Botto, R.I. Quality Assurance in Operating a Multielement ICP Emission Spectrometer. Spectrochim. Acta, 39B(1):95-113, 1984.

18. Wallace, G.F., Some Factors Affecting the Performance of an ICP Sample Introduction System. Atomic Spectroscopy, Vol. 4, p. 188-192, 1983.

19. Koirtyohann, S.R. et al. Nomenclature System for the Low-Power Argon Inductively Coupled Plasma, Anal. Chem. 52:1965, 1980.

20. Deming, S.N. and S.L. Morgan. Experimental Design for Quality and Productivity in Research, Development, and Manufacturing, Part III, pp. 119-123. Short course publication by Statistical Designs, 9941 Rowlett, Suite 6, Houston, TX 77075, 1989.

21. Winefordner, J.D., Trace Analysis: Spectroscopic Methods for Elements, Chemical Analysis, Vol. 46, pp. 41-42.

22. Jones, C.L. et al. An Interlaboratory Study of Inductively Coupled Plasma Atomic Emission Spectroscopy Method 6010 and Digestion Method 3050. EPA-600/4-87-032, U.S. Environmental Protection Agency, Las Vegas, Nevada, 1987.

23. Martin, T.D., E.R. Martin and SE. Long. Method 200.2: Sample Preparation Procedure for Spectrochemical Analyses of Total Recoverable Elements, EMSL ORD, USEPA, 1989.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

Table 1—Wavelengths, Estimated Instrument Detection Limits, and Recommended Calibration

Analyte
Wavelength
a

(nm)
Estimated

detection

limit
b (µg/L)
Calibrate
c

to (mg/L)
Aluminum308.2154510
Antimony206.833325
Arsenic193.7595310
Barium493.4092.31
Beryllium313.0420.271
Boron249.6785.71
Cadmium226.5023.42
Calcium315.8873010
Cerium413.765482
Chromium205.5526.15
Cobalt228.6167.02
Copper324.7545.42
Iron259.9406.210
Lead220.3534210
Lithium670.784
d 3.7		5
Magnesium279.0793010
Manganese257.6101.42
Mercury194.2272.52
Molybdenum203.8441210
Nickel231.604152
Phosphorus214.9147610
Potassium766.491
e 700		20
Selenium196.090755
Silica (SiO2)251.611
d 26 (SiO2)		10
Silver328.0687.00.5
Sodium588.9952910
Strontium421.5520.771
Thallium190.864405
Tin189.980254
Titanium334.9413.810
Vanadium292.4027.52
Zinc213.8561.85


a The wavelengths listed are recommended because of their sensitivity and overall acceptability. Other wavelengths may be substituted if they can provide the needed sensitivity and are treated with the same corrective techniques for spectral interference (see Section 4.1).


b These estimated 3-sigma instrumental detection limits
16 are provided only as a guide to instrumental limits. The method detection limits are sample dependent and may vary as the sample matrix varies. Detection limits for solids can be estimated by dividing these values by the grams extracted per liter, which depends upon the extraction procedure. Divide solution detection limits by 10 for 1 g extracted to 100 mL for solid detection limits.


c Suggested concentration for instrument calibration.
2 Other calibration limits in the linear ranges may be used.


d Calculated from 2-sigma data.
5


e Highly dependent on operating conditions and plasma position.


TABLE 2—On-Line Method Interelement Spectral Interferances Arising From Interferants at the 100 mg/L Level

Analyte
Wavelength (nm)
Interferant*
Ag

Al

As

B

Ba

Be

Ca

Cd

Ce

Co

Cr

Cu

Fe

Hg

K

Li

Mg

Mn

Mo

Na

Ni

P

Pb

Sb

Se

SiO2

Sn

Sr

Tl

Ti

V

Zn		328.068

308.215

193.759

249.678

493.409

313.042

315.887

226.502

413.765

228.616

205.552

324.754

259.940

194.227

766.491

670.784

279.079

257.610

203.844

588.995

231.604

214.914

220.353

206.833

196.099

251.611

189.980

421.552

190.864

334.941

292.402

213.856		Ce, Ti, Mn

V, Mo, Ce, Mn

V, Al, Co, Fe, Ni

None

None

V, Ce

Co, Mo, Ce

Ni, Ti, Fe, Ce

None

Ti, Ba, Cd, Ni, Cr, Mo, Ce

Be, Mo, Ni

Mo, Ti

None

V, Mo

None

None

Ce

Ce

Ce

None

Co, Tl

Cu, Mo

Co, Al, Ce, Cu, Ni, Ti, Fe

Cr, Mo, Sn, Ti, Ce, Fe

Fe

None

Mo, Ti, Fe, Mn, Si

None

Ti, Mo, Co, Ce, Al, V, Mn

None

Mo, Ti, Cr, Fe, Ce

Ni, Cu, Fe

* These on-line interferences from method analytes and titanium only were observed using an instrument with 0.035 nm resolution (see Section 4.1.2). Interferant ranked by magnitude of intensity with the most severe interferant listed first in the row.


TABLE 3—Mixed Standard Solutions

Solution
Analytes
I

II

III

IV

V		Ag, As, B, Ba, Ca, Cd, Cu, Mn, Sb, and Se

K, Li, Mo, Na, Sr, and Ti

Co, P, V, and Ce

Al, Cr, Hg, SiO2, Sn, and Zn

Be, Fe, Mg, Ni, Pb, and Tl

TABLE 4—Total Recoverable Method Detection Limits (MDL)

Analyte
MDLs

Aqueous, mg/L
(1)
Solids, mg/kg
(2)
Ag0.0020.3
Al0.023
As0.0082
B0.003—
Ba0.0010.2
Be0.00030.1
Ca0.012
Cd0.0010.2
Ce0.023
Co0.0020.4
Cr0.0040.8
Cu0.0030.5
Fe*0.036
Hg0.0072
K0.360
Li0.0010.2
Mg0.023
Mn0.0010.2
Mo0.0041
Na0.036
Ni0.0051
P0.0612
Pb0.012
Sb0.0082
Se0.025
SiO20.02—
Sn0.0072
Sr0.00030.1
Tl0.0010.2
Ti0.023
V0.0031
Zn0.0020.3


(1) MDL concentrations are computed for original matrix with allowance for 2x sample preconcentration during preparation. Samples were processed in PTFE and diluted in 50-mL plastic centrifuge tubes.


(2) Estimated, calculated from aqueous MDL determinations.

— Boron not reported because of glassware contamination. Silica not determined in solid samples.

* Elevated value due to fume-hood contamination.


TABLE 5—Inductively Coupled Plasma Instrument Operating Conditions

Incident rf power1100 watts
Reflected rf power
Viewing height above work coil15 mm
Injector tube orifice i.d.1 mm
Argon supplyliquid argon
Argon pressure40 psi
Coolant argon flow rate19 L/min.
Aerosol carrier argon flow rate620 mL/min.
Auxiliary (plasma) argon flow rate300 mL/min.
Sample uptake rate controlled to1.2 mL/min.

Table 6—Precision and Recovery Data in Aqueous Matrices

Analyte
Sample conc.

mg/L
Low spike

mg/L
Average

recovery

R (%)
S (R)
RPD
High spike

mg/L
Average

recovery

R (%)
S (R)
RPD
Tap Water
Ag0.05950.72.10.2960.00.0
Al0.1850.05988.81.70.21053.03.1
As0.051081.43.70.21010.72.0
B0.0230.1980.20.00.4980.20.5
Ba0.0420.051021.62.20.2980.40.8
Be0.011000.00.00.1990.00.0
Ca35.25.01018.81.720.01032.00.9
Cd0.011053.59.50.1980.00.0
Co0.021000.00.00.2990.51.5
Cr0.011100.00.00.11020.00.0
Cu0.021031.84.90.21011.23.5
Fe0.0080.11061.01.80.41050.30.5
Hg0.051030.71.90.21000.41.0
K1.985.01091.42.320.1070.71.7
Li0.0060.021036.93.80.21101.94.4
Mg8.085.01042.21.520.01000.71.1
Mn0.011000.00.00.1990.00.0
Mo0.02953.510.50.21080.51.4
Na10.35.0993.02.020.01061.01.6
Ni0.021081.84.70.21041.12.9
P0.0450.110213.19.40.41043.21.3
Pb0.05950.72.10.21000.20.5
Sb0.05990.72.00.21020.72.0
Se0.1871.13.50.4990.82.3
SiO26.55.01043.33.420.0961.12.3
Sn0.051032.15.80.21011.85.0
Sr0.1810.11023.32.10.41050.81.0
Tl0.11013.910.90.41010.10.3
V0.051010.72.00.2990.20.5
Zn0.0050.051013.79.00.2980.92.5
Pond Water
Ag 0.05920.00.00.2940.00.0
Al0.8190.28810.05.00.81002.93.7
As0.051020.00.00.2981.44.1
B0.0340.11118.96.90.41032.00.0
Ba0.0290.05960.90.00.2970.30.5
Be0.01950.41.10.2950.00.0
Ca53.95.0**0.720.01002.01.5
Cd0.011070.00.00.1970.00.0
Co0.021002.77.50.2970.72.1
Cr0.011053.59.50.11031.12.9
Cu0.02982.14.40.21000.51.5
Fe0.8750.2958.92.80.8973.23.6
Hg0.05973.510.30.2980.00.0
K2.485.01060.30.120.01030.20.4
Li0.021100.00.00.21060.20.5
Mg10.85.01020.50.020.0960.71.3
Mn0.6320.01**0.20.1972.30.3
Mo0.021053.59.50.21030.41.0
Na17.85.01031.30.420.0940.30.0
Ni0.02965.69.10.21000.71.5
P0.1960.19114.70.30.41083.91.3
Pb0.05962.67.80.21000.72.0
Sb0.051022.87.80.21040.41.0
Se0.11042.15.80.41031.64.4
SiO27.835.01511.61.320.01170.40.6
Sn0.05980.00.00.2991.13.0
Sr0.1290.11050.40.00.4990.10.2
Tl0.11031.12.90.4971.33.9
V0.0030.05940.40.00.2980.10.0
Zn0.0060.05971.61.80.2940.40.0
Well Water
Ag0.05970.72.10.2960.20.5
Al0.0360.051077.610.10.21011.10.8
As0.051070.71.90.21040.41.0
B0.0630.1970.60.70.4980.82.1
Ba0.1020.051023.00.00.2990.91.0
Be0.011000.00.00.11000.00.0
Ca93.85.0**2.120.01004.10.1
Cd0.0020.01900.00.00.1960.00.0
Co0.02940.41.10.2940.41.1
Cr0.011007.120.00.11000.41.0
Cu0.021001.10.40.2960.51.5
Fe0.0420.1992.31.40.4971.43.3
Hg0.05942.88.50.2931.23.8
K6.215.0963.43.620.01011.22.3
Li0.0010.021007.69.50.21041.01.9
Mg24.55.0955.60.320.0931.61.2
Mn2.760.01**0.40.1**0.7
Mo0.021081.84.70.21010.20.5
Na35.05.010111.40.820.01003.11.5
Ni0.021121.84.40.2960.20.5
P0.1970.19512.71.90.4983.40.9
Pb0.05874.916.10.2950.20.5
Sb0.05982.88.20.2991.44.0
Se0.11020.41.00.4941.13.4
SiO213.15.0934.82.820.0990.80.0
Sn0.05982.88.20.2940.20.5
Sr0.2740.1945.72.70.4951.72.2
Tl0.1920.41.10.4951.13.2
V0.05980.00.00.2990.41.0
Zn0.5380.05**0.70.2992.51.1
Sewage Treatment Effluent
Ag0.0090.05921.53.60.2950.10.0
Al1.190.05**0.90.211312.42.1
As0.05992.16.10.2932.16.5
B0.2260.121716.39.50.411913.120.9
Ba0.1890.05906.81.70.2991.60.5
Be0.01940.41.10.11000.41.0
Ca87.95.0**0.620.01013.70.0
Cd0.0090.01892.62.30.1970.41.0
Co0.0160.02953.10.00.2930.40.5
Cr0.1280.01**1.50.1972.42.7
Cu0.1740.029833.14.70.2983.01.4
Fe1.280.1**2.80.41117.00.6
Hg0.051021.43.90.2980.51.5
K10.65.01042.81.320.01010.60.0
Li0.0110.021038.53.20.21050.80.5
Mg22.75.01004.40.020.0921.10.2
Mn0.1990.01**2.00.11041.90.3
Mo0.1250.0211021.26.80.21021.30.9
Na0.2365.0**0.020.0**0.4
Ni0.0870.0212210.74.50.2980.81.1
P4.710.1**2.60.4**1.4
Pb0.0150.05913.55.00.2961.32.9
Sb0.05970.72.10.21031.12.9
Se0.11083.910.00.41012.67.2
SiO216.75.01244.00.920.01081.10.8
Sn0.0160.05903.80.00.2951.00.0
Sr0.5150.11036.40.50.4961.60.2
Tl0.11050.41.00.4950.00.0
V0.0030.05930.92.00.2970.20.5
Zn0.1600.05983.31.90.21011.01.4
Industrial Effluent
Ag0.05880.00.00.2840.93.0
Al0.0540.058811.712.20.2903.98.1
As0.05822.89.80.2880.51.7
B0.170.116217.613.90.4924.79.3
Ba0.0830.05868.21.60.2852.32.4
Be0.01940.41.10.1821.44.9
Ca5005.0**2.820.0**2.3
Cd0.0080.01854.76.10.1821.44.4
Co0.02931.85.40.2830.41.2
Cr0.1650.01**4.50.11066.65.6
Cu0.0950.029323.30.90.2952.72.8
Fe0.3150.18816.41.00.4996.58.0
Hg0.05870.72.30.2860.41.2
K2.875.01013.42.420.01000.80.4
Li0.0690.0210324.75.60.21042.52.2
Mg6.845.0873.10.020.0870.91.2
Mn0.1410.01**1.20.1896.64.8
Mo1.270.02**0.00.210015.02.7
Na15005.0**2.720.0**2.0
Ni0.0140.02984.43.00.2870.51.1
P0.3260.110516.04.70.4973.91.4
Pb0.2510.058019.91.40.2885.00.9
Sb2.810.05**0.40.2**2.0
Se0.0210.11062.63.20.41051.94.6
SiO26.835.0996.81.720.01002.23.0
Sn0.05870.72.30.2860.41.2
Sr6.540.1**2.00.4**2.7
Tl0.1871.85.80.4841.13.6
V0.05901.44.40.2841.13.6
Zn0.0240.05896.04.40.2913.58.9

S (R) Standard deviation of percent recovery.

RPD Relative percent difference between duplicate spike determinations.

* Spike concentration


Table 7—Precision and Recovery Data in Solid Matrices

Analyte
Sample conc.

mg/kg
Low + spike

mg/kg
Average

recovery R (%)
S (R)
RPD
High + spike

mg/kg
Average

recovery R (%)
S (R)
RPD
EPA Hazardous Soil #884
Ag1.120980.71.0100960.20.6
Al508020**7.2100**5.4
As5.720955.410.6100961.43.6
B20.4100932.75.34001002.15.5
Ba111209871.422.21009710.01.0
Be0.6620970.72.3100990.10.2
Ca85200−−−−−−−−
Cd220930.71.0100940.20.4
Co5.520963.57.7100930.82.1
Cr79.7208728.816.51001041.31.1
Cu1132011016.24.41001044.04.2
Fe16500−−−−−−−−
Hg10922.57.740980.00.0
K6215001211.30.020001070.91.8
Li6.7101133.54.4401060.60.6
Mg24400500**8.42000**10.1
Mn34320**8.51009511.01.6
Mo5.320885.313.2100911.44.1
Na1955001022.22.420001001.53.7
Ni15.6201001.80.0100941.53.6
P59550010613.48.020001033.22.7
Pb145208851.817.910010815.617.4
Sb6.120833.97.5100811.95.9
Se207914.752.4100990.72.1
Sn16.6209134.65.8801128.72.8
Sr102100849.610.8400942.54.6
Tl20924.814.6100911.54.6
V16.7201044.25.4100990.81.7
Zn1312010331.27.31001047.26.4
EPA Electroplating Sludge #286
Ag620960.20.4100930.10.4
Al498020**4.4100**5.6
As3220941.30.8100970.71.6
B2101001132.01.6400981.93.5
Ba39.82006.80.310001.65.7
Be0.3220960.20.51001010.72.0
Ca48500−−−−−−−−
Cd10820982.50.8100960.50.5
Co5.920932.95.7100930.61.5
Cr758020**0.7100**1.3
Cu80620**1.5100948.30.7
Fe31100−−−−−−−−
Hg6.110902.54.040971.74.3
K2390500758.34.02000942.93.8
Li9.1101012.80.5401061.63.1
Mg19505001102.00.820001082.33.2
Mn26220**1.8100911.20.9
Mo13.220922.12.9100920.30.0
Na73400500**1.72000**1.4
Ni45620**0.4100882.70.9
P9610500**2.920001147.43.4
Pb142020**2.1100**1.3
Sb20760.93.3100752.810.7
Se6.320869.016.61001031.62.7
Sn24.020874.02.780920.70.0
Sr145100908.18.1400932.44.6
Tl1620894.65.3100920.80.9
V21.720951.21.0100960.40.9
Zn1250020**0.8100**0.8
NBS 1645 River Sediment
Ag1.620920.41.0100960.30.9
Al516020**8.4100**2.4
As62.8208914.49.7100972.95.0
B31.91001167.113.5400950.61.5
Ba54.820956.12.8100981.21.3
Be0.72201010.41.01001031.43.9
Ca28000−−−−−−−−
Cd9.7201001.10.01001010.71.8
Co9.420983.84.8100980.91.8
Cr2850020**0.4100**0.7
Cu109201158.50.01001021.81.0
Fe84800−−−−−−−−
Hg3.110994.37.740960.71.0
K452500984.12.020001061.42.3
Li3.7101012.00.7401081.33.0
Mg6360500**1.82000932.71.0
Mn72820**3.51009712.42.2
Mo17.9209712.518.5100980.60.0
Na1020500922.60.02000971.11.7
Ni36.220945.94.01001001.11.5
P5535001021.40.920001000.81.6
Pb70720**0.81001035.90.4
Sb22.820862.30.0100880.60.9
Se6.72010314.327.1100983.17.6
Sn30920**1.0801017.92.7
Sr7821009112.33.0400963.32.6
Tl20900.00.0100951.34.0
V20.120895.45.8100980.70.0
Zn164020**1.8100**1.1

S (R) Standard deviation of percent recovery.

RPD Relative percent difference between duplicate spike determinations.

* Spike concentration

− Not spiked.

+ Equivalent.


Table 8—ICP-AES Instrumental Precision and Accuracy for Aqueous Solutions
a

Element
Mean conc.

(mg/L)
N
b
RSD (%)
Accurace
c

(% of Nominal)
Al14.886.3100
Sb15.187.7102
As14.776.499
Ba3.6673.199
Be3.7885.8102
Cd3.6187.097
Ca15.087.4101
Cr3.7588.2101
Co3.5285.995
Cu3.5885.697
Fe14.885.9100
Pb14.475.997
Mg14.186.596
Mn3.7084.3100
Mo3.7086.9100
Ni3.7075.7100
K14.186.695
Se15.387.5104
Na14.084.295
Tl15.178.5102
V3.5186.695
Zn3.5788.396


a These performance values are independent of sample preparation because the labs analyzed portions of the same solutions using sequential or simultaneous instruments.


b N = Number of measurements for mean and relative standard deviation (RSD).


c Accuracy is expressed as a percentage of the nominal value for each analyte in the acidified, multi-element solutions.


Table 9—Multilaboratory ICP Precision and Accuracy Data*

Analyte
Concentration

µg/L
Total recoverable digestion

µ/L
Aluminum69-4792X = 0.9380 (C) + 22.1
SR = 0.0481 (X) + 18.8
Antimony77-14060.8908 (C) + 0.9
SR = 0.0682 (X) + 2.5
Arsenic69-1887X = 1.0175 (C) + 3.9
SR = 0.0643 (X) + 10.3
Barium9-377X = 0.8.80 (C) + 1.68
SR = 0.0826 (X) + 3.54
Beryllium3-1906X = 1.0177 (C) − 0.55
SR = 0.0445 (X) − 0.10
Boron19-5189X = 0.9676 (C) + 18.7
SR = 0.0743 (X) + 21.1
Cadmium9-1943X = 1.0137 (C) − 0.65
SR = 0.0332 (X) + 0.90
Calcium17-47170X = 0.9658 (C) + 0.8
SR = 0.0327 (X) + 10.1
Chromium13-1406X = 1.0049 (C) − 1.2
SR = 0.0571 (X) + 1.0
Cobalt17-2340X = 0.9278 (C) + 1.5
SR = 0.0407 (X) + 0.4
Copper8-1887X = 0.9647 (C) − 3.64
SR = 0.0406 (X) + 0.96
Iron13-9359X = 0.9830 (C) + 5.7
SR = 0.0790 (X) + 11.5
Lead42-4717X = 1.0056 (C) + 4.1
SR = 0.0448 (X) + 3.5
Magnesium34-13868X = 0.9879 (C) + 2.2
SR = 0.0268 (X) + 8.1
Manganese4-1887X = 0.9725 (C) + 0.07
SR = 0.0400 (X) + 0.82
Molybdenum17-1830X = 0.9707 (C) − 2.3
SR = 0.0529 (X) + 2.1
Nickel17-47170X = 0.9869 (C) + 1.5
SR = 0.0393 (X) + 2.2
Potassium347-14151X = 0.9355 (C) − 183.1
SR = 0.0329 (X) + 60.9
Selenium69-1415X = 0.9737 (C) − 1.0
SR = 0.0443 (X) + 6.6
Silicon189-9434X = 0.9737 (C) − 22.6
SR = 0.2133 (X) + 22.6
Silver8-189X = 0.3987 (C) + 8.25
SR = 0.1836 (X) − 0.27
Sodium35-47170X = 1.0526 (C) + 26.7
SR = 0.0884 (X) + 50.5
Thallium79-1434X = 0.9238 (C) + 5.5
SR = 0.0106 (X) + 48.0
Vanadium13-4698X = 0.9551 (C) + 0.4
SR = 0.0472 (X) + 0.5
Zinc7-7076X = 0.9500 (C) + 1.82
SR = 0.0153 (X) + 7.78

*—Regression equations abstracted from Reference 16.

X = Mean Recovery, µg/L.

C = True Value for the Concentration, µg/L.

SR = Single-analyst Standard Deviation, µg/L.



[77 FR 29813, May 18, 2012]


Appendix D to Part 136—Precision and Recovery Statements for Methods for Measuring Metals

Two selected methods from “Methods for Chemical Analysis of Water and Wastes,” EPA-600/4-79-020 (1979) have been subjected to interlaboratory method validation studies. The two selected methods are for Thallium and Zinc. The following precision and recovery statements are presented in this appendix and incorporated into Part 136:


Method 279.2

For Thallium, Method 279.2 (Atomic Absorption, Furnace Technique) replace the Precision and Accuracy Section statement with the following:


Precision and Accuracy

An interlaboratory study on metal analyses by this method was conducted by the Quality Assurance Branch (QAB) of the Environmental Monitoring Systems Laboratory—Cincinnati (EMSL-CI). Synthetic concentrates containing various levels of this element were added to reagent water, surface water, drinking water and three effluents. These samples were digested by the total digestion procedure, 4.1.3 in this manual. Results for the reagent water are given below. Results for other water types and study details are found in “EPA Method Study 31, Trace Metals by Atomic Absorption (Furnace Techniques),” National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 Order No. PB 86-121 704/AS, by Copeland, F.R. and Maney, J.P., January 1986.


For a concentration range of 10.00-252 µg/L


X = 0.8781(C) − 0.715

S = 0.1112(X) + 0.669

SR = 0.1005(X) + 0.241

Where:

C = True Value for the Concentration, µg/L

X = Mean Recovery, µg/L

S = Multi-laboratory Standard Deviation, µg/L

SR = Single-analyst Standard Deviation, µg/L

Method 289.2

For Zinc, Method 289.2 (Atomic Absorption, Furnace Technique) replace the Precision and Accuracy Section statement with the following:


Precision and Accuracy

An interlaboratory study on metal analyses by this method was conducted by the Quality Assurance Branch (QAB) of the Environmental Monitoring Systems Laboratory—Cincinnati (EMSL-CI). Synthetic concentrates containing various levels of this element were added to reagent water, surface water, drinking water and three effluents. These samples were digested by the total digestion procedure, 4.1.3 in this manual. Results for the reagent water are given below. Results for other water types and study details are found in “EPA Method Study 31, Trace Metals by Atomic Absorption (Furnace Techniques),” National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 Order No. PB 86-121 704/AS, by Copeland, F.R. and Maney, J.P., January 1986.


For a concentration range of 0.51-189 µg/L


X = 1.6710(C) + 1.485

S = 0.6740(X) − 0.342

SR = 0.3895(X)− 0.384

Where:

C = True Value for the Concentration, µg/L

X = Mean Recovery, µg/L

S = Multi-laboratory Standard Deviation, µg/L

SR = Single-analyst Standard Deviation, µg/L

[77 FR 29833, May 18, 2012]


PART 140—MARINE SANITATION DEVICE STANDARD


Authority:33 U.S.C. 1322, as amended.


Source:41 FR 4453, Jan. 29, 1976, unless otherwise noted.

§ 140.1 Definitions.

For the purpose of these standards the following definitions shall apply:


(a) Sewage means human body wastes and the wastes from toilets and other receptacles intended to receive or retain body wastes;


(b) Discharge includes, but is not limited to, any spilling, leaking, pumping, pouring, emitting, emptying, or dumping;


(c) Marine sanitation device includes any equipment for installation onboard a vessel and which is designed to receive, retain, treat, or discharge sewage and any process to treat such sewage;


(d) Vessel includes every description of watercraft or other artificial contrivance used, or capable of being used, as a means of transportation on waters of the United States;


(e) New vessel refers to any vessel on which construction was initiated on or after January 30, 1975;


(f) Existing vessel refers to any vessel on which construction was initiated before January 30, 1975;


(g) Fecal coliform bacteria are those organisms associated with the intestines of warm-blooded animals that are commonly used to indicate the presence of fecal material and the potential presence of organisms capable of causing human disease.


§ 140.2 Scope of standard.

The standard adopted herein applies only to vessels on which a marine sanitation device has been installed. The standard does not require the installation of a marine sanitation device on any vessel that is not so equipped. The standard applies to vessels owned and operated by the United States unless the Secretary of Defense finds that compliance would not be in the interest of national security.


§ 140.3 Standard.

(a) (1) In freshwater lakes, freshwater reservoirs or other freshwater impoundments whose inlets or outlets are such as to prevent the ingress or egress by vessel traffic subject to this regulation, or in rivers not capable of navigation by interstate vessel traffic subject to this regulation, marine sanitation devices certified by the U.S. Coast Guard (see 33 CFR part 159, published in 40 FR 4622, January 30, 1975), installed on all vessels shall be designed and operated to prevent the overboard discharge of sewage, treated or untreated, or of any waste derived from sewage. This shall not be construed to prohibit the carriage of Coast Guard-certified flow-through treatment devices which have been secured so as to prevent such discharges.


(2) In all other waters, Coast Guard-certified marine sanitation devices installed on all vessels shall be designed and operated to either retain, dispose of, or discharge sewage. If the device has a discharge, subject to paragraph (d) of this section, the effluent shall not have a fecal coliform bacterial count of greater than 1,000 per 100 milliliters nor visible floating solids. Waters where a Coast Guard-certified marine sanitation device permitting discharge is allowed include coastal waters and estuaries, the Great Lakes and inter-connected waterways, fresh-water lakes and impoundments accessible through locks, and other flowing waters that are navigable interstate by vessels subject to this regulation.


(b) This standard shall become effective on January 30, 1977 for new vessels and on January 30, 1980 for existing vessels (or, in the case of vessels owned and operated by the Department of Defense, two years and five years, for new and existing vessels, respectively, after promulgation of implementing regulations by the Secretary of Defense under section 312(d) of the Act).


(c) Any vessel which is equipped as of the date of promulgation of this regulation with a Coast Guard-certified flow-through marine sanitation device meeting the requirements of paragraph (a)(2) of this section, shall not be required to comply with the provisions designed to prevent the overboard discharge of sewage, treated or untreated, in paragraph (a)(1) of this section, for the operable life of that device.


(d) After January 30, 1980, subject to paragraphs (e) and (f) of this section, marine sanitation devices on all vessels on waters that are not subject to a prohibition of the overboard discharge of sewage, treated or untreated, as specified in paragraph (a)(1) of this section, shall be designed and operated to either retain, dispose of, or discharge sewage, and shall be certified by the U.S. Coast Guard. If the device has a discharge, the effluent shall not have a fecal coliform bacterial count of greater than 200 per 100 milliliters, nor suspended solids greater than 150 mg/1.


(e) Any existing vessel on waters not subject to a prohibition of the overboard discharge of sewage in paragraph (a)(1) of this section, and which is equipped with a certified device on or before January 30, 1978, shall not be required to comply with paragraph (d) of this section, for the operable life of that device.


(f) Any new vessel on waters not subject to the prohibition of the overboard discharge of sewage in paragraph (a)(1) of this section, and on which construction is initiated before January 31, 1980, which is equipped with a marine sanitation device before January 31, 1980, certified under paragraph (a)(2) of this section, shall not be required to comply with paragraph (d) of this section, for the operable life of that device.


(g) The degrees of treatment described in paragraphs (a) and (d) of this section are “appropriate standards” for purposes of Coast Guard and Department of Defense certification pursuant to section 312(g)(2) of the Act.


[41 FR 4453, Jan. 29, 1976, as amended at 60 FR 33932, June 29, 1995]


§ 140.4 Complete prohibition.

(a) Prohibition pursuant to CWA section 312(f)(3): a State may completely prohibit the discharge from all vessels of any sewage, whether treated or not, into some or all of the waters within such State by making a written application to the Administrator, Environmental Protection Agency, and by receiving the Administrator’s affirmative determination pursuant to section 312(f)(3) of the Act. Upon receipt of an application under section 312(f)(3) of the Act, the Administrator will determine within 90 days whether adequate facilities for the safe and sanitary removal and treatment of sewage from all vessels using such waters are reasonably available. Applications made by States pursuant to section 312(f)(3) of the Act shall include:


(1) A certification that the protection and enhancement of the waters described in the petition require greater environmental protection than the applicable Federal standard;


(2) A map showing the location of commercial and recreational pump-out facilities;


(3) A description of the location of pump-out facilities within waters designated for no discharge;


(4) The general schedule of operating hours of the pump-out facilities;


(5) The draught requirements on vessels that may be excluded because of insufficient water depth adjacent to the facility;


(6) Information indicating that treatment of wastes from such pump-out facilities is in conformance with Federal law; and


(7) Information on vessel population and vessel usage of the subject waters.


(b) Prohibition pursuant to CWA section 312(f)(4)(A): a State may make a written application to the Administrator, Environmental Protection Agency, under section 312(f)(4)(A) of the Act, for the issuance of a regulation completely prohibiting discharge from a vessel of any sewage, whether treated or not, into particular waters of the United States or specified portions thereof, which waters are located within the boundaries of such State. Such application shall specify with particularly the waters, or portions thereof, for which a complete prohibition is desired. The application shall include identification of water recreational areas, drinking water intakes, aquatic sanctuaries, identifiable fish-spawning and nursery areas, and areas of intensive boating activities. If, on the basis of the State’s application and any other information available to him, the Administrator is unable to make a finding that the waters listed in the application require a complete prohibition of any discharge in the waters or portions thereof covered by the application, he shall state the reasons why he cannot make such a finding, and shall deny the application. If the Administrator makes a finding that the waters listed in the application require a complete prohibition of any discharge in all or any part of the waters or portions thereof covered by the State’s application, he shall publish notice of such findings together with a notice of proposed rule making, and then shall proceed in accordance with 5 U.S.C. 553. If the Administrator’s finding is that applicable water quality standards require a complete prohibition covering a more restricted or more expanded area than that applied for by the State, he shall state the reasons why his finding differs in scope from that requested in the State’s application.


(1) For the following waters the discharge from a vessel of any sewage (whether treated or not) is completely prohibited pursuant to CWA section 312(f)(4)(A):


(i) Boundary Waters Canoe Area, formerly designated as the Superior, Little Indian Sioux, and Caribou Roadless Areas, in the Superior National Forest, Minnesota, as described in 16 U.S.C. 577-577d1.


(ii) Waters of the State of Florida within the boundaries of the Florida Keys National Marine Sanctuary as delineated on a map of the Sanctuary at http://www.fknms.nos.noaa.gov/.


(2)(i) For the marine waters of the State of California, the following vessels are completely prohibited from discharging any sewage (whether treated or not):


(A) A large passenger vessel;


(B) A large oceangoing vessel equipped with a holding tank which has not fully used the holding tank’s capacity, or which contains more than de minimis amounts of sewage generated while the vessel was outside of the marine waters of the State of California.


(ii) For purposes of paragraph (b)(2) of this section:


(A) “Marine waters of the State of California” means the territorial sea measured from the baseline as determined in accordance with the Convention on the Territorial Sea and the Contiguous Zone and extending seaward a distance of three miles, and all enclosed bays and estuaries subject to tidal influences from the Oregon border (41.999325 North Latitude, 124.212110 West Longitude, decimal degrees, NAD 1983) to the Mexican border (32.471231 North Latitude, 117.137814 West Longitude, decimal degrees, NAD 1983). A map illustrating these waters can be obtained from EPA or viewed at http://www.epa.gov/region9/water/no-discharge/overview.html.


(B) A “large passenger vessel” means a passenger vessel, as defined in section 2101(22) of title 46, United States Code, of 300 gross tons or more, as measured under the International Convention on Tonnage Measurement of Ships, 1969, measurement system in 46 U.S.C. 14302, or the regulatory measurement system of 46 U.S.C. 14502 for vessels not measured under 46 U.S.C. 14302, that has berths or overnight accommodations for passengers.


(C) A “large oceangoing vessel” means a private, commercial, government, or military vessel of 300 gross tons or more, as measured under the International Convention on Tonnage Measurement of Ships, 1969, measurement system in 46 U.S.C. 14302, or the regulatory measurement system of 46 U.S.C. 14502 for vessels not measured under 46 U.S.C.14302, that is not a large passenger vessel.


(D) A “holding tank” means a tank specifically designed, constructed, and fitted for the retention of treated or untreated sewage, that has been designated and approved by the ship’s flag Administration on the ship’s stability plan; a designated ballast tank is not a holding tank for this purpose.


(c)(1) Prohibition pursuant to CWA section 312(f)(4)(B): A State may make written application to the Administrator of the Environmental Protection Agency under section 312(f)(4)(B) of the Act for the issuance of a regulation establishing a drinking water intake no discharge zone which completely prohibits discharge from a vessel of any sewage, whether treated or untreated, into that zone in particular waters, or portions thereof, within such State. Such application shall:


(i) Identify and describe exactly and in detail the location of the drinking water supply intake(s) and the community served by the intake(s), including average and maximum expected amounts of inflow;


(ii) Specify and describe exactly and in detail, the waters, or portions thereof, for which a complete prohibition is desired, and where appropriate, average, maximum and low flows in million gallons per day (MGD) or the metric equivalent;


(iii) Include a map, either a USGS topographic quadrant map or a NOAA nautical chart, as applicable, clearly marking by latitude and longitude the waters or portions thereof to be designated a drinking water intake zone; and


(iv) Include a statement of basis justifying the size of the requested drinking water intake zone, for example, identifying areas of intensive boating activities.


(2) If the Administrator finds that a complete prohibition is appropriate under this paragraph, he or she shall publish notice of such finding together with a notice of proposed rulemaking, and then shall proceed in accordance with 5 U.S.C. 553. If the Administrator’s finding is that a complete prohibition covering a more restricted or more expanded area than that applied for by the State is appropriate, he or she shall also include a statement of the reasons why the finding differs in scope from that requested in the State’s application.


(3) If the Administrator finds that a complete prohibition is inappropriate under this paragraph, he or she shall deny the application and state the reasons for such denial.


(4) For the following waters the discharge from a vessel of any sewage, whether treated or not, is completely prohibited pursuant to CWA section 312(f)(4)(B):


(i) Two portions of the Hudson River in New York State, the first is bounded by an east-west line through the most northern confluence of the Mohawk River which will be designated by the Troy-Waterford Bridge (126th Street Bridge) on the south and Lock 2 on the north, and the second of which is bounded on the north by the southern end of Houghtaling Island and on the south by a line between the Village of Roseton on the western shore and Low Point on the eastern shore in the vicinity of Chelsea, as described in Items 2 and 3 of 6 NYCRR Part 858.4.


(ii) [Reserved]


[41 FR 4453, Jan. 29, 1976, as amended at 42 FR 43837, Aug. 31, 1977; 60 FR 63945, Dec. 13, 1995; 63 FR 1320, Jan. 8, 1998; 67 FR 35743, May 21, 2002; 77 FR 11411, Feb. 27, 2012]


§ 140.5 Analytical procedures.

In determining the composition and quality of effluent discharge from marine sanitation devices, the procedures contained in 40 CFR part 136, “Guidelines Establishing Test Procedures for the Analysis of Pollutants,” or subsequent revisions or amendments thereto, shall be employed.


PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS


Authority:42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j-9, and 300j-11.


Source:40 FR 59570, Dec. 24, 1975, unless otherwise noted.


Editorial Note:Nomenclature changes to part 141 appear at 69 FR 18803, Apr. 9, 2004.

Note:

For community water systems serving 75,000 or more persons, monitoring must begin 1 year following promulation and the effective date of the MCL is 2 years following promulgation. For community water systems serving 10,000 to 75,000 persons, monitoring must begin within 3 years from the date of promulgation and the effective date of the MCL is 4 years from the date of promulgation. Effective immediately, systems that plan to make significant modifications to their treatment processes for the purpose of complying with the TTHM MCL are required to seek and obtain State approval of their treatment modification plans. This note affects §§ 141.2, 141.6, 141.12, 141.24 and 141.30. For additional information see 44 FR 68641, Nov. 29, 1979.

Subpart A—General

§ 141.1 Applicability.

This part establishes primary drinking water regulations pursuant to section 1412 of the Public Health Service Act, as amended by the Safe Drinking Water Act (Pub. L. 93-523); and related regulations applicable to public water systems.


§ 141.2 Definitions.

As used in this part, the term:


Act means the Public Health Service Act, as amended by the Safe Drinking Water Act, Public Law 93-523.


Action level means the concentrations of lead or copper in water as specified in § 141.80(c) which determines requirements under subpart I of this part. The action level for lead is 0.015 mg/L and the action level for copper is 1.3 mg/L.


Aerator means the device embedded in the water faucet to enhance air flow with the water stream and to prevent splashing.


Bag filters are pressure-driven separation devices that remove particulate matter larger than 1 micrometer using an engineered porous filtration media. They are typically constructed of a non-rigid, fabric filtration media housed in a pressure vessel in which the direction of flow is from the inside of the bag to outside.


Bank filtration is a water treatment process that uses a well to recover surface water that has naturally infiltrated into ground water through a river bed or bank(s). Infiltration is typically enhanced by the hydraulic gradient imposed by a nearby pumping water supply or other well(s).


Best available technology or BAT means the best technology, treatment techniques, or other means which the Administrator finds, after examination for efficacy under field conditions and not solely under laboratory conditions, are available (taking cost into consideration). For the purposes of setting MCLs for synthetic organic chemicals, any BAT must be at least as effective as granular activated carbon.


Cartridge filters are pressure-driven separation devices that remove particulate matter larger than 1 micrometer using an engineered porous filtration media. They are typically constructed as rigid or semi-rigid, self-supporting filter elements housed in pressure vessels in which flow is from the outside of the cartridge to the inside.


Child care facility means a location that houses a licensed provider of child care, day care, or early learning services to children, as determined by the State, local, or tribal licensing agency.


Clean compliance history is, for the purposes of subpart Y, a record of no MCL violations under § 141.63; no monitoring violations under § 141.21 or subpart Y; and no coliform treatment technique trigger exceedances or treatment technique violations under subpart Y.


Coagulation means a process using coagulant chemicals and mixing by which colloidal and suspended materials are destabilized and agglomerated into flocs.


Combined distribution system is the interconnected distribution system consisting of the distribution systems of wholesale systems and of the consecutive systems that receive finished water.


Community water system means a public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents.


Compliance cycle means the nine-year calendar year cycle during which public water systems must monitor. Each compliance cycle consists of three three-year compliance periods. The first calendar year cycle begins January 1, 1993 and ends December 31, 2001; the second begins January 1, 2002 and ends December 31, 2010; the third begins January 1, 2011 and ends December 31, 2019.


Compliance period means a three-year calendar year period within a compliance cycle. Each compliance cycle has three three-year compliance periods. Within the first compliance cycle, the first compliance period runs from January 1, 1993 to December 31, 1995; the second from January 1, 1996 to December 31, 1998; the third from January 1, 1999 to December 31, 2001.


Comprehensive performance evaluation (CPE) is a thorough review and analysis of a treatment plant’s performance-based capabilities and associated administrative, operation and maintenance practices. It is conducted to identify factors that may be adversely impacting a plant’s capability to achieve compliance and emphasizes approaches that can be implemented without significant capital improvements. For purpose of compliance with subparts P and T of this part, the comprehensive performance evaluation must consist of at least the following components: Assessment of plant performance; evaluation of major unit processes; identification and prioritization of performance limiting factors; assessment of the applicability of comprehensive technical assistance; and preparation of a CPE report.


Confluent growth means a continuous bacterial growth covering the entire filtration area of a membrane filter, or a portion thereof, in which bacterial colonies are not discrete.


Consecutive system is a public water system that receives some or all of its finished water from one or more wholesale systems. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems.


Contaminant means any physical, chemical, biological, or radiological substance or matter in water.


Conventional filtration treatment means a series of processes including coagulation, flocculation, sedimentation, and filtration resulting in substantial particulate removal.


Corrosion inhibitor means a substance capable of reducing the corrosivity of water toward metal plumbing materials, especially lead and copper, by forming a protective film on the interior surface of those materials.


CT or CTcalc is the product of “residual disinfectant concentration” (C) in mg/1 determined before or at the first customer, and the corresponding “disinfectant contact time” (T) in minutes, i.e., “C” × “T”. If a public water system applies disinfectants at more than one point prior to the first customer, it must determine the CT of each disinfectant sequence before or at the first customer to determine the total percent inactivation or “total inactivation ratio.” In determining the total inactivation ratio, the public water system must determine the residual disinfectant concentration of each disinfection sequence and corresponding contact time before any subsequent disinfection application point(s). “CT99.9” is the CT value required for 99.9 percent (3-log) inactivation of Giardia lamblia cysts. CT99.9 for a variety of disinfectants and conditions appear in tables 1.1-1.6, 2.1, and 3.1 of § 141.74(b)(3).




is the inactivation ratio. The sum of the inactivation ratios, or total inactivation ratio shown as



is calculated by adding together the inactivation ratio for each disinfection sequence. A total inactivation ratio equal to or greater than 1.0 is assumed to provide a 3-log inactivation of Giardia lamblia cysts.

Diatomaceous earth filtration means a process resulting in substantial particulate removal in which (1) a precoat cake of diatomaceous earth filter media is deposited on a support membrance (septum), and (2) while the water is filtered by passing through the cake on the septum, additional filter media known as body feed is continuously added to the feed water to maintain the permeability of the filter cake.


Direct filtration means a series of processes including coagulation and filtration but excluding sedimentation resulting in substantial particulate removal.


Disinfectant means any oxidant, including but not limited to chlorine, chlorine dioxide, chloramines, and ozone added to water in any part of the treatment or distribution process, that is intended to kill or inactivate pathogenic microorganisms.


Disinfectant contact time (“T” in CT calculations) means the time in minutes that it takes for water to move from the point of disinfectant application or the previous point of disinfectant residual measurement to a point before or at the point where residual disinfectant concentration (“C”) is measured. Where only one “C” is measured, “T” is the time in minutes that it takes for water to move from the point of disinfectant application to a point before or at where residual disinfectant concentration (“C”) is measured. Where more than one “C” is measured, “T” is (a) for the first measurement of “C”, the time in minutes that it takes for water to move from the first or only point of disinfectant application to a point before or at the point where the first “C” is measured and (b) for subsequent measurements of “C”, the time in minutes that it takes for water to move from the previous “C” measurement point to the “C” measurement point for which the particular “T” is being calculated. Disinfectant contact time in pipelines must be calculated based on “plug flow” by dividing the internal volume of the pipe by the maximum hourly flow rate through that pipe. Disinfectant contact time within mixing basins and storage reservoirs must be determined by tracer studies or an equivalent demonstration.


Disinfection means a process which inactivates pathogenic organisms in water by chemical oxidants or equivalent agents.


Disinfection profile is a summary of Giardia lamblia inactivation through the treatment plant. The procedure for developing a disinfection profile is contained in § 141.172 (Disinfection profiling and benchmarking) in subpart P and §§ 141.530-141.536 (Disinfection profile) in subpart T of this part.


Domestic or other non-distribution system plumbing problem means a coliform contamination problem in a public water system with more than one service connection that is limited to the specific service connection from which the coliform-positive sample was taken.


Dose equivalent means the product of the absorbed dose from ionizing radiation and such factors as account for differences in biological effectiveness due to the type of radiation and its distribution in the body as specified by the International Commission on Radiological Units and Measurements (ICRU).


Dual sample set is a set of two samples collected at the same time and same location, with one sample analyzed for TTHM and the other sample analyzed for HAA5. Dual sample sets are collected for the purposes of conducting an IDSE under subpart U of this part and determining compliance with the TTHM and HAA5 MCLs under subpart V of this part.


Effective corrosion inhibitor residual, for the purpose of subpart I of this part only, means a concentration sufficient to form a passivating film on the interior walls of a pipe.


Elementary school, for the purposes of subpart I of this part only, means a school classified as elementary by state and local practice and composed of any span of grades (including pre-school) not above grade 8.


Enhanced coagulation means the addition of sufficient coagulant for improved removal of disinfection byproduct precursors by conventional filtration treatment.


Enhanced softening means the improved removal of disinfection byproduct precursors by precipitative softening.


Fifth liter sample, for purposes of subpart I of this part, means a one-liter sample of tap water collected in accordance with § 141.86(b).


Filter profile is a graphical representation of individual filter performance, based on continuous turbidity measurements or total particle counts versus time for an entire filter run, from startup to backwash inclusively, that includes an assessment of filter performance while another filter is being backwashed.


Filtration means a process for removing particulate matter from water by passage through porous media.


Find-and-fix means the requirements under subpart I of this part that water systems must perform at every tap sampling site that yielded a lead result above 15 µg/L.


Finished water is water that is introduced into the distribution system of a public water system and is intended for distribution and consumption without further treatment, except as treatment necessary to maintain water quality in the distribution system (e.g., booster disinfection, addition of corrosion control chemicals).


First draw sample means the first one-liter sample of tap water collected in accordance with § 141.86(b)(2).


Flocculation means a process to enhance agglomeration or collection of smaller floc particles into larger, more easily settleable particles through gentle stirring by hydraulic or mechanical means.


Flowing stream is a course of running water flowing in a definite channel.


Full lead service line replacement means the replacement of a lead service line (as well as galvanized service lines requiring replacement), as defined in this section, that results in the entire length of the service line, regardless of service line ownership, meeting the Safe Drinking Water Act (SDWA) Section 1417 definition of lead free applicable at the time of the replacement. A full lead service line replacement includes a replacement where only one portion of the service line is lead, such as where a partial lead service line was previously conducted, as long as, upon completion of the replacement, the entire service line meets the SDWA Section 1417 definition of lead-free applicable at the time of the replacement. Galvanized service lines that are or were downstream of a lead service line must also be replaced for a service line to be a full lead service line replacement. A lead service line that is left in place in the ground but remains out-of-service may be full lead service line replacement where a new non-lead service line is installed for use instead of the out-of-service lead service line.


GAC10 means granular activated carbon filter beds with an empty-bed contact time of 10 minutes based on average daily flow and a carbon reactivation frequency of every 180 days, except that the reactivation frequency for GAC10 used as a best available technology for compliance with subpart V MCLs under § 141.64(b)(2) shall be 120 days.


GAC20 means granular activated carbon filter beds with an empty-bed contact time of 20 minutes based on average daily flow and a carbon reactivation frequency of every 240 days.


Galvanized service line means iron or steel piping that has been dipped in zinc to prevent corrosion and rusting.


Gooseneck, pigtail, or connector is a short section of piping, typically not exceeding two feet, which can be bent and used for connections between rigid service piping. For purposes of this subpart, lead goosenecks, pigtails, and connectors are not considered to be part of the lead service line but may be required to be replaced pursuant to § 141.84(c).


Ground water under the direct influence of surface water (GWUDI) means any water beneath the surface of the ground with significant occurrence of insects or other macroorganisms, algae, or large-diameter pathogens such as Giardia lamblia or Cryptosporidium, or significant and relatively rapid shifts in water characteristics such as turbidity, temperature, conductivity, or pH which closely correlate to climatological or surface water conditions. Direct influence must be determined for individual sources in accordance with criteria established by the State. The State determination of direct influence may be based on site-specific measurements of water quality and/or documentation of well construction characteristics and geology with field evaluation.


Gross alpha particle activity means the total radioactivity due to alpha particle emission as inferred from measurements on a dry sample.


Gross beta particle activity means the total radioactivity due to beta particle emission as inferred from measurements on a dry sample.


Haloacetic acids (five) (HAA5) mean the sum of the concentrations in milligrams per liter of the haloacetic acid compounds (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid), rounded to two significant figures after addition.


Halogen means one of the chemical elements chlorine, bromine or iodine.


Initial compliance period means the first full three-year compliance period which begins at least 18 months after promulgation, except for contaminants listed at § 141.61(a) (19)-(21), (c) (19)-(33), and § 141.62(b) (11)-(15), initial compliance period means the first full three-year compliance period after promulgation for systems with 150 or more service connections (January 1993-December 1995), and first full three-year compliance period after the effective date of the regulation (January 1996-December 1998) for systems having fewer than 150 service connections.


Lake/reservoir refers to a natural or man made basin or hollow on the Earth’s surface in which water collects or is stored that may or may not have a current or single direction of flow.


Large water system, for the purpose of subpart I of this part only, means a water system that serves more than 50,000 persons.


Lead service line means a portion of pipe that is made of lead, which connects the water main to the building inlet. A lead service line may be owned by the water system, owned by the property owner, or both. For the purposes of this subpart, a galvanized service line is considered a lead service line if it ever was or is currently downstream of any lead service line or service line of unknown material. If the only lead piping serving the home is a lead gooseneck, pigtail, or connector, and it is not a galvanized service line that is considered a lead service line the service line is not a lead service line. For purposes of § 141.86(a) only, a galvanized service line is not considered a lead service line.


Lead status unknown service line means a service line that has not been demonstrated to meet or not meet the SDWA Section 1417 definition of lead free. It is not necessary to physically verify the material composition (for example, copper or plastic) of a service line for its lead status to be identified (e.g., records demonstrating the service line was installed after a municipal, State, or Federal lead ban).


Lead trigger level means a particular concentration of lead in water that prompts certain activities under subpart I of this part. The trigger level for lead is a concentration of 10 µg/L.


Legionella means a genus of bacteria, some species of which have caused a type of pneumonia called Legionnaires Disease.


Level 1 assessment is an evaluation to identify the possible presence of sanitary defects, defects in distribution system coliform monitoring practices, and (when possible) the likely reason that the system triggered the assessment. It is conducted by the system operator or owner. Minimum elements include review and identification of atypical events that could affect distributed water quality or indicate that distributed water quality was impaired; changes in distribution system maintenance and operation that could affect distributed water quality (including water storage); source and treatment considerations that bear on distributed water quality, where appropriate (e.g., whether a ground water system is disinfected); existing water quality monitoring data; and inadequacies in sample sites, sampling protocol, and sample processing. The system must conduct the assessment consistent with any State directives that tailor specific assessment elements with respect to the size and type of the system and the size, type, and characteristics of the distribution system.


Level 2 assessment is an evaluation to identify the possible presence of sanitary defects, defects in distribution system coliform monitoring practices, and (when possible) the likely reason that the system triggered the assessment. A Level 2 assessment provides a more detailed examination of the system (including the system’s monitoring and operational practices) than does a Level 1 assessment through the use of more comprehensive investigation and review of available information, additional internal and external resources, and other relevant practices. It is conducted by an individual approved by the State, which may include the system operator. Minimum elements include review and identification of atypical events that could affect distributed water quality or indicate that distributed water quality was impaired; changes in distribution system maintenance and operation that could affect distributed water quality (including water storage); source and treatment considerations that bear on distributed water quality, where appropriate (e.g., whether a ground water system is disinfected); existing water quality monitoring data; and inadequacies in sample sites, sampling protocol, and sample processing. The system must conduct the assessment consistent with any State directives that tailor specific assessment elements with respect to the size and type of the system and the size, type, and characteristics of the distribution system. The system must comply with any expedited actions or additional actions required by the State in the case of an E. coli MCL violation.


Locational running annual average (LRAA) is the average of sample analytical results for samples taken at a particular monitoring location during the previous four calendar quarters.


Man-made beta particle and photon emitters means all radionuclides emitting beta particles and/or photons listed in Maximum Permissible Body Burdens and Maximum Permissible Concentration of Radionuclides in Air or Water for Occupational Exposure, NBS Handbook 69, except the daughter products of thorium-232, uranium-235 and uranium-238.


Maximum contaminant level means the maximum permissable level of a contaminant in water which is delivered to any user of a public water system.


Maximum contaminant level goal or MCLG means the maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on the health of persons would occur, and which allows an adequate margin of safety. Maximum contaminant level goals are nonenforceable health goals.


Maximum residual disinfectant level (MRDL) means a level of a disinfectant added for water treatment that may not be exceeded at the consumer’s tap without an unacceptable possibility of adverse health effects. For chlorine and chloramines, a PWS is in compliance with the MRDL when the running annual average of monthly averages of samples taken in the distribution system, computed quarterly, is less than or equal to the MRDL. For chlorine dioxide, a PWS is in compliance with the MRDL when daily samples are taken at the entrance to the distribution system and no two consecutive daily samples exceed the MRDL. MRDLs are enforceable in the same manner as maximum contaminant levels under Section 1412 of the Safe Drinking Water Act. There is convincing evidence that addition of a disinfectant is necessary for control of waterborne microbial contaminants. Notwithstanding the MRDLs listed in § 141.65, operators may increase residual disinfectant levels of chlorine or chloramines (but not chlorine dioxide) in the distribution system to a level and for a time necessary to protect public health to address specific microbiological contamination problems caused by circumstances such as distribution line breaks, storm runoff events, source water contamination, or cross-connections.


Maximum residual disinfectant level goal (MRDLG) means the maximum level of a disinfectant added for water treatment at which no known or anticipated adverse effect on the health of persons would occur, and which allows an adequate margin of safety. MRDLGs are nonenforceable health goals and do not reflect the benefit of the addition of the chemical for control of waterborne microbial contaminants.


Maximum Total Trihalomethane Potential (MTP) means the maximum concentration of total trihalomethanes produced in a given water containing a disinfectant residual after 7 days at a temperature of 25 °C or above.


Medium-size water system, for the purpose of subpart I of this part only, means a water system that serves greater than 10,000 persons and less than or equal to 50,000 persons.


Membrane filtration is a pressure or vacuum driven separation process in which particulate matter larger than 1 micrometer is rejected by an engineered barrier, primarily through a size-exclusion mechanism, and which has a measurable removal efficiency of a target organism that can be verified through the application of a direct integrity test. This definition includes the common membrane technologies of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis.


Method detection limit (MDL) means the minimum concentration of a substance that can be measured and reported with 99 percent confidence that the analyte concentration is greater than zero and is determined from analysis of a sample in a given matrix containing the analyte.


Near the first service connection means at one of the 20 percent of all service connections in the entire system that are nearest the water supply treatment facility, as measured by water transport time within the distribution system.


Non-community water system means a public water system that is not a community water system. A non-community water system is either a “transient non-community water system (TWS)” or a “non-transient non-community water system (NTNCWS).”


Non-transient non-community water system or NTNCWS means a public water system that is not a community water system and that regularly serves at least 25 of the same persons over 6 months per year.


Optimal corrosion control treatment, for the purpose of subpart I of this part only, means the corrosion control treatment that minimizes the lead and copper concentrations at users’ taps while insuring that the treatment does not cause the water system to violate any national primary drinking water regulations.


Partial lead service line replacement means replacement of any portion of a lead service line or galvanized service line requiring replacement, as defined in this section, that leaves in service any length of lead service line or galvanized service line requiring replacement upon completion of the work. Partial lead service line replacements are permitted under limited circumstances under § 141.84(d) but do not count towards the mandatory or goal-based lead service line replacement rate.


Performance evaluation sample means a reference sample provided to a laboratory for the purpose of demonstrating that the laboratory can successfully analyze the sample within limits of performance specified by the Agency. The true value of the concentration of the reference material is unknown to the laboratory at the time of the analysis.


Person means an individual; corporation; company; association; partnership; municipality; or State, Federal, or tribal agency.


Picocurie (pCi) means the quantity of radioactive material producing 2.22 nuclear transformations per minute.


Pitcher filter means a non-plumbed water filtration device which consists of a gravity fed water filtration cartridge and a filtered drinking water reservoir that is certified by an American National Standards Institute accredited certifier to reduce lead in drinking water.


Plant intake refers to the works or structures at the head of a conduit through which water is diverted from a source (e.g., river or lake) into the treatment plant.


Point of disinfectant application is the point where the disinfectant is applied and water downstream of that point is not subject to recontamination by surface water runoff.


Point-of-entry treatment device (POE) is a treatment device applied to the drinking water entering a house or building for the purpose of reducing contaminants in the drinking water distributed throughout the house or building.


Point-of-use treatment device or point of use device (POU) is a water treatment device physically installed or connected to a single fixture, outlet, or tap to reduce or remove contaminants in drinking water. For the purposes of subpart I of this part, it must be certified by an American National Standards Institute accredited certifier to reduce lead in drinking water.


Practical quantitation limit (PQL) means the minimum concentration of an analyte (substance) that can be measured with a high degree of confidence that the analyte is present at or above that concentration.


Presedimentation is a preliminary treatment process used to remove gravel, sand and other particulate material from the source water through settling before the water enters the primary clarification and filtration processes in a treatment plant.


Pre-stagnation flushing is the opening of tap(s) to flush standing water from plumbing prior to the minimum 6-hour stagnation period in anticipation of lead and copper tap sampling under subpart I of this part.


Public water system means a system for the provision to the public of water for human consumption through pipes or, after August 5, 1998, other constructed conveyances, if such system has at least fifteen service connections or regularly serves an average of at least twenty-five individuals daily at least 60 days out of the year. Such term includes: any collection, treatment, storage, and distribution facilities under control of the operator of such system and used primarily in connection with such system; and any collection or pretreatment storage facilities not under such control which are used primarily in connection with such system. Such term does not include any “special irrigation district.” A public water system is either a “community water system” or a “noncommunity water system.”


Rem means the unit of dose equivalent from ionizing radiation to the total body or any internal organ or organ system. A “millirem (mrem)” is
1/1000 of a rem.


Repeat compliance period means any subsequent compliance period after the initial compliance period.


Residual disinfectant concentration (“C” in CT calculations) means the concentration of disinfectant measured in mg/l in a representative sample of water.


Sanitary defect is a defect that could provide a pathway of entry for microbial contamination into the distribution system or that is indicative of a failure or imminent failure in a barrier that is already in place.


Sanitary survey means an onsite review of the water source, facilities, equipment, operation and maintenance of a public water system for the purpose of evaluating the adequacy of such source, facilities, equipment, operation and maintenance for producing and distributing safe drinking water.


School, for the purpose of subpart I of this part only, means any building(s) associated with public, private, or charter institutions that primarily provides teaching and learning for elementary or secondary students.


Seasonal system is a non-community water system that is not operated as a public water system on a year-round basis and starts up and shuts down at the beginning and end of each operating season.


Secondary school, for the purpose of subpart I of this part only, means a school comprising any span of grades beginning with the next grade following an elementary or middle school (usually 7, 8, or 9) and ending with or below grade 12. Both junior high schools and senior high schools are included.


Sedimentation means a process for removal of solids before filtration by gravity or separation.


Service connection, as used in the definition of public water system, does not include a connection to a system that delivers water by a constructed conveyance other than a pipe if:


(1) The water is used exclusively for purposes other than residential uses (consisting of drinking, bathing, and cooking, or other similar uses);


(2) The State determines that alternative water to achieve the equivalent level of public health protection provided by the applicable national primary drinking water regulation is provided for residential or similar uses for drinking and cooking; or


(3) The State determines that the water provided for residential or similar uses for drinking, cooking, and bathing is centrally treated or treated at the point of entry by the provider, a pass-through entity, or the user to achieve the equivalent level of protection provided by the applicable national primary drinking water regulations.


Single family structure, for the purpose of subpart I of this part only, means a building constructed as a single-family residence that is currently used as either a residence or a place of business.


Slow sand filtration means a process involving passage of raw water through a bed of sand at low velocity (generally less than 0.4 m/h) resulting in substantial particulate removal by physical and biological mechanisms.


Small water system, for the purpose of subpart I of this part only, means a water system that serves 3,300 persons or fewer.


Special irrigation district means an irrigation district in existence prior to May 18, 1994 that provides primarily agricultural service through a piped water system with only incidental residential or similar use where the system or the residential or similar users of the system comply with the exclusion provisions in section 1401(4)(B)(i)(II) or (III).


Standard sample means the aliquot of finished drinking water that is examined for the presence of coliform bacteria.


State means the agency of the State or Tribal government which has jurisdiction over public water systems. During any period when a State or Tribal government does not have primary enforcement responsibility pursuant to section 1413 of the Act, the term “State” means the Regional Administrator, U.S. Environmental Protection Agency.


Subpart H systems means public water systems using surface water or ground water under the direct influence of surface water as a source that are subject to the requirements of subpart H of this part.


Supplier of water means any person who owns or operates a public water system.


Surface water means all water which is open to the atmosphere and subject to surface runoff.


SUVA means Specific Ultraviolet Absorption at 254 nanometers (nm), an indicator of the humic content of water. It is a calculated parameter obtained by dividing a sample’s ultraviolet absorption at a wavelength of 254 nm (UV 254) (in m
= 1) by its concentration of dissolved organic carbon (DOC) (in mg/L).


System with a single service connection means a system which supplies drinking water to consumers via a single service line.


System without corrosion control treatment means a public water system that does not have or purchases all of its water from a system that does not have:


(1) An optimal corrosion control treatment approved by the State; or


(2) Any pH adjustment, alkalinity adjustment, and/or corrosion inhibitor addition resulting from other water quality adjustments as part of its treatment train infrastructure.


Tap sampling monitoring period, for the purposes of subpart I of this part, means the period of time during which each water system must conduct tap sampling for lead and copper analysis. A tap sampling monitoring period is determined by lead and copper concentrations in tap samples and the frequency can range from every six months (i.e., semi-annual) up to once every nine years. Water systems on semi-annual tap sampling monitoring must collect samples no less frequently than every six months while those on annual monitoring must sample no less frequently than every year. Water systems on triennial monitoring must collect samples no less frequently than every three years; and those on monitoring waivers must sample no less frequently than every nine years. The start of each new tap sampling monitoring period, with the exception of semi-annual monitoring, must begin on January 1.


Tap sampling period, for the purpose of subpart I of this part only, means the time period, within a tap sampling monitoring period, during which the water system is required to collect samples for lead and copper analysis. For systems monitoring at a reduced frequency, the tap sampling period must be between the months of June and September, unless a different 4-month period of time is approved in writing to be more appropriate by the State.


Tap sampling protocol means the instructions given to residents or those sampling on behalf of the water system to conduct tap sampling under subpart I of this part.


Too numerous to count means that the total number of bacterial colonies exceeds 200 on a 47-mm diameter membrane filter used for coliform detection.


Total Organic Carbon (TOC) means total organic carbon in mg/L measured using heat, oxygen, ultraviolet irradiation, chemical oxidants, or combinations of these oxidants that convert organic carbon to carbon dioxide, rounded to two significant figures.


Total trihalomethanes (TTHM) means the sum of the concentration in milligrams per liter of the trihalomethane compounds (trichloromethane [chloroform], dibromochloromethane, bromodichloromethane and tribromomethane [bromoform]), rounded to two significant figures.


Transient non-community water system or TWS means a non-community water system that does not regularly serve at least 25 of the same persons over six months per year.


Trihalomethane (THM) means one of the family of organic compounds, named as derivatives of methane, wherein three of the four hydrogen atoms in methane are each substituted by a halogen atom in the molecular structure.


Two-stage lime softening is a process in which chemical addition and hardness precipitation occur in each of two distinct unit clarification processes in series prior to filtration.


Uncovered finished water storage facility is a tank, reservoir, or other facility used to store water that will undergo no further treatment to reduce microbial pathogens except residual disinfection and is directly open to the atmosphere.


Virus means a virus of fecal origin which is infectious to humans by waterborne transmission.


Waterborne disease outbreak means the significant occurrence of acute infectious illness, epidemiologically associated with the ingestion of water from a public water system which is deficient in treatment, as determined by the appropriate local or State agency.


Wholesale system is a public water system that treats source water as necessary to produce finished water and then delivers some or all of that finished water to another public water system. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems.


Wide-mouth bottles, for the purpose of subpart I of this part only, means bottles configured with a mouth that is at least 55 mm wide that are one liter in size.


[40 FR 59570, Dec. 24, 1975]


Editorial Note:For Federal Register citations affecting § 141.2, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

§ 141.3 Coverage.

This part shall apply to each public water system, unless the public water system meets all of the following conditions:


(a) Consists only of distribution and storage facilities (and does not have any collection and treatment facilities);


(b) Obtains all of its water from, but is not owned or operated by, a public water system to which such regulations apply:


(c) Does not sell water to any person; and


(d) Is not a carrier which conveys passengers in interstate commerce.


§ 141.4 Variances and exemptions.

(a) Variances or exemptions from certain provisions of these regulations may be granted pursuant to sections 1415 and 1416 of the Act and subpart K of part 142 of this chapter (for small system variances) by the entity with primary enforcement responsibility, except that variances or exemptions from the MCLs for total coliforms and E. coli and variances from any of the treatment technique requirements of subpart H of this part may not be granted.


(b) EPA has stayed the effective date of this section relating to the total coliform MCL of § 141.63(a) for systems that demonstrate to the State that the violation of the total coliform MCL is due to a persistent growth of total coliforms in the distribution system rather than fecal or pathogenic contamination, a treatment lapse or deficiency, or a problem in the operation or maintenance of the distribution system. This is stayed until March 31, 2016, at which time the total coliform MCL is no longer effective.



Note to paragraph (a):

As provided in § 142.304(a), small system variances are not available for rules addressing microbial contaminants, which would include subparts H, P, S, T, W, and Y of this part.


[78 FR 10346, Feb. 13, 2013]


§ 141.5 Siting requirements.

Before a person may enter into a financial commitment for or initiate construction of a new public water system or increase the capacity of an existing public water system, he shall notify the State and, to the extent practicable, avoid locating part or all of the new or expanded facility at a site which:


(a) Is subject to a significant risk from earthquakes, floods, fires or other disasters which could cause a breakdown of the public water system or a portion thereof; or


(b) Except for intake structures, is within the floodplain of a 100-year flood or is lower than any recorded high tide where appropriate records exist. The U.S. Environmental Protection Agency will not seek to override land use decisions affecting public water systems siting which are made at the State or local government levels.


§ 141.6 Effective dates.

(a) Except as provided in paragraphs (b) through (k) of this section, and in § 141.80(a)(2), the regulations set forth in this part shall take effect on June 24, 1977.


(b) The regulations for total trihalomethanes set forth in § 141.12(c) shall take effect 2 years after the date of promulgation of these regulations for community water systems serving 75,000 or more individuals, and 4 years after the date of promulgation for communities serving 10,000 to 74,999 individuals.


(c) The regulations set forth in §§ 141.11(d); 141.21(a), (c) and (i); 141.22(a) and (e); 141.23(a)(3) and (a)(4); 141.23(f); 141.24(e) and (f); 141.25(e); 141.27(a); 141.28(a) and (b); 141.31(a), (d) and (e); 141.32(b)(3); and 141.32(d) shall take effect immediately upon promulgation.


(d) The regulations set forth in § 141.41 shall take effect 18 months from the date of promulgation. Suppliers must complete the first round of sampling and reporting within 12 months following the effective date.


(e) The regulations set forth in § 141.42 shall take effect 18 months from the date of promulgation. All requirements in § 141.42 must be completed within 12 months following the effective date.


(f) The regulations set forth in § 141.11(c) and § 141.23(g) are effective May 2, 1986. Section 141.23(g)(4) is effective October 2, 1987.


(g) The regulations contained in § 141.6, paragraph (c) of the table in 141.12, and 141.62(b)(1) are effective July 1, 1991. The regulations contained in §§ 141.11(b), 141.23, 141.24, 142.57(b), 143.4(b)(12) and (b)(13), are effective July 30, 1992. The regulations contained in the revisions to §§ 141.32(e) (16), (25) through (27) and (46); 141.61(c)(16); and 141.62(b)(3) are effective January 1, 1993. The effective date of regulations contained in § 141.61(c) (2), (3), and (4) is postponed.


(h) Regulations for the analytic methods listed at § 141.23(k)(4) for measuring antimony, beryllium, cyanide, nickel, and thallium are effective August 17, 1992. Regulations for the analytic methods listed at § 141.24(f)(16) for dichloromethane, 1,2,4-trichlorobenzene, and 1,1,2-trichloroethane are effective August 17, 1992. Regulations for the analytic methods listed at § 141.24(h)(12) for measuring dalapon, dinoseb, diquat, endothall, endrin, glyphosate, oxamyl, picloram, simazine, benzo(a)pyrene, di(2-ethylhexyl)adipate, di(2-ethylhexyl)phthalate, hexachlorobenzene, hexachlorocyclopentadiene, and 2,3,7,8-TCDD are effective August 17, 1992. The revision to § 141.12(a) promulgated on July 17, 1992 is effective on August 17, 1992.


(i) [Reserved]


(j) The arsenic maximum contaminant levels (MCL) listed in § 141.62 is effective for the purpose of compliance on January 23, 2006. Requirements relating to arsenic set forth in §§ 141.23(i)(4), 141.23(k)(3) introductory text, 141.23(k)(3)(ii), 141.51(b), 141.62(b), 141.62(b)(16), 141.62(c), 141.62(d), and 142.62(b) revisions in Appendix A of subpart O for the consumer confidence rule, and Appendices A and B of subpart Q for the public notification rule are effective for the purpose of compliance on January 23, 2006. However, the consumer confidence rule reporting requirements relating to arsenic listed in § 141.154(b) and (f) are effective for the purpose of compliance on February 22, 2002.


(k) Regulations set forth in §§ 141.23(i)(1), 141.23(i)(2), 141.24(f)(15), 141.24(f)(22), 141.24(h)(11), 141.24(h)(20), 142.16(e), 142.16(j), and 142.16(k) are effective for the purpose of compliance on January 22, 2004.


[44 FR 68641, Nov. 29, 1979, as amended at 45 FR 57342, Aug. 27, 1980; 47 FR 10998, Mar. 12, 1982; 51 FR 11410, Apr. 2, 1986; 56 FR 30274, July 1, 1991; 57 FR 22178, May 27, 1992; 57 FR 31838, July 17, 1992; 59 FR 34322, July 1, 1994; 61 FR 24368, May 14, 1996; 66 FR 7061, Jan. 22, 2001; 66 FR 28350, May 22, 2001]


Subpart B—Maximum Contaminant Levels

§ 141.11 Maximum contaminant levels for inorganic chemicals.

(a) The maximum contaminant level for arsenic applies only to community water systems. The analyses and determination of compliance with the 0.05 milligrams per liter maximum contaminant level for arsenic use the requirements of § 141.23.


(b) The maximum contaminant level for arsenic is 0.05 milligrams per liter for community water systems until January 23, 2006.


(c) [Reserved]


(d) At the discretion of the State, nitrate levels not to exceed 20 mg/l may be allowed in a non-community water system if the supplier of water demonstrates to the satisfaction of the State that:


(1) Such water will not be available to children under 6 months of age; and


(2) The non-community water system is meeting the public notification requirements under § 141.209, including continuous posting of the fact that nitrate levels exceed 10 mg/l and the potential health effects of exposure; and


(3) Local and State public health authorities will be notified annually of nitrate levels that exceed 10 mg/l; and


(4) No adverse health effects shall result.


[40 FR 59570, Dec. 24, 1975, as amended at 45 FR 57342, Aug. 27, 1980; 47 FR 10998, Mar. 12, 1982; 51 FR 11410, Apr. 2, 1986; 56 FR 3578, Jan. 30, 1991; 56 FR 26548, June 7, 1991; 56 FR 30274, July 1, 1991; 56 FR 32113, July 15, 1991; 60 FR 33932, June 29, 1995; 65 FR 26022, May 4, 2000; 66 FR 7061, Jan. 22, 2001]


§ 141.12 [Reserved]

§ 141.13 Maximum contaminant levels for turbidity.

The maximum contaminant levels for turbidity are applicable to both community water systems and non-community water systems using surface water sources in whole or in part. The maximum contaminant levels for turbidity in drinking water, measured at a representative entry point(s) to the distribution system, are:


(a) One turbidity unit (TU), as determined by a monthly average pursuant to § 141.22, except that five or fewer turbidity units may be allowed if the supplier of water can demonstrate to the State that the higher turbidity does not do any of the following:


(1) Interfere with disinfection;


(2) Prevent maintenance of an effective disinfectant agent throughout the distribution system; or


(3) Interfere with microbiological determinations.


(b) Five turbidity units based on an average for two consecutive days pursuant to § 141.22.


[40 FR 59570, Dec. 24, 1975]


Subpart C—Monitoring and Analytical Requirements

§ 141.21 Coliform sampling.

(a) Routine monitoring. (1) Public water systems must collect total coliform samples at sites which are representative of water throughout the distribution system according to a written sample siting plan. These plans are subject to State review and revision.


(2) The monitoring frequency for total coliforms for community water systems is based on the population served by the system, as follows:


Total Coliform Monitoring Frequency for Community Water Systems

Population served
Minimum number of samples per month
25 to 1,000
1		1
1,001 to 2,5002
2,501 to 3,3003
3,301 to 4,1004
4,101 to 4,9005
4,901 to 5,8006
5,801 to 6,7007
6,701 to 7,6008
7,601 to 8,5009
8,501 to 12,90010
12,901 to 17,20015
17,201 to 21,50020
21,501 to 25,00025
25,001 to 33,00030
33,001 to 41,00040
41,001 to 50,00050
50,001 to 59,00060
59,001 to 70,00070
70,001 to 83,00080
83,001 to 96,00090
96,001 to 130,000100
130,001 to 220,000120
220,001 to 320,000150
320,001 to 450,000180
450,001 to 600,000210
600,001 to 780,000240
780,001 to 970,000270
970,001 to 1,230,000300
1,230,001 to 1,520,000330
1,520,001 to 1,850,000360
1,850,001 to 2,270,000390
2,270,001 to 3,020,000420
3,020,001 to 3,960,000450
3,960,001 or more480


1 Includes public water systems which have at least 15 service connections, but serve fewer than 25 persons.


If a community water system serving 25 to 1,000 persons has no history of total coliform contamination in its current configuration and a sanitary survey conducted in the past five years shows that the system is supplied solely by a protected groundwater source and is free of sanitary defects, the State may reduce the monitoring frequency specified above, except that in no case may the State reduce the monitoring frequency to less than one sample per quarter. The State must approve the reduced monitoring frequency in writing.

(3) The monitoring frequency for total coliforms for non-community water systems is as follows:


(i) A non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving 1,000 persons or fewer must monitor each calendar quarter that the system provides water to the public, except that the State may reduce this monitoring frequency, in writing, if a sanitary survey shows that the system is free of sanitary defects. Beginning June 29, 1994, the State cannot reduce the monitoring frequency for a non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving 1,000 persons or fewer to less than once/year.


(ii) A non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in § 141.2) and serving more than 1,000 persons during any month must monitor at the same frequency as a like-sized community water system, as specified in paragraph (a)(2) of this section, except the State may reduce this monitoring frequency, in writing, for any month the system serves 1,000 persons or fewer. The State cannot reduce the monitoring frequency to less than once/year. For systems using ground water under the direct influence of surface water, paragraph (a)(3)(iv) of this section applies.


(iii) A non-community water system using surface water, in total or in part, must monitor at the same frequency as a like-sized community water system, as specified in paragraph (a)(2) of this section, regardless of the number of persons it serves.


(iv) A non-community water system using ground water under the direct influence of surface water, as defined in § 141.2, must monitor at the same frequency as a like-sized community water system, as specified in paragraph (a)(2) of this section. The system must begin monitoring at this frequency beginning six months after the State determines that the ground water is under the direct influence of surface water.


(4) The public water system must collect samples at regular time intervals throughout the month, except that a system which uses only ground water (except ground water under the direct influence of surface water, as defined in § 141.2), and serves 4,900 persons or fewer, may collect all required samples on a single day if they are taken from different sites.


(5) A public water system that uses surface water or ground water under the direct influence of surface water, as defined in § 141.2, and does not practice filtration in compliance with Subpart H must collect at least one sample near the first service connection each day the turbidity level of the source water, measured as specified in § 141.74(b)(2), exceeds 1 NTU. This sample must be analyzed for the presence of total coliforms. When one or more turbidity measurements in any day exceed 1 NTU, the system must collect this coliform sample within 24 hours of the first exceedance, unless the State determines that the system, for logistical reasons outside the system’s control, cannot have the sample analyzed within 30 hours of collection. Sample results from this coliform monitoring must be included in determining compliance with the MCL for total coliforms in § 141.63.


(6) Special purpose samples, such as those taken to determine whether disinfection practices are sufficient following pipe placement, replacement, or repair, shall not be used to determine compliance with the MCL for total coliforms in § 141.63. Repeat samples taken pursuant to paragraph (b) of this section are not considered special purpose samples, and must be used to determine compliance with the MCL for total coliforms in § 141.63.


(b) Repeat monitoring. (1) If a routine sample is total coliform-positive, the public water system must collect a set of repeat samples within 24 hours of being notified of the positive result. A system which collects more than one routine sample/month must collect no fewer than three repeat samples for each total coliform-positive sample found. A system which collects one routine sample/month or fewer must collect no fewer than four repeat samples for each total coliform-positive sample found. The State may extend the 24-hour limit on a case-by-case basis if the system has a logistical problem in collecting the repeat samples within 24 hours that is beyond its control. In the case of an extension, the State must specify how much time the system has to collect the repeat samples.


(2) The system must collect at least one repeat sample from the sampling tap where the original total coliform-positive sample was taken, and at least one repeat sample at a tap within five service connections upstream and at least one repeat sample at a tap within five service connections downstream of the original sampling site. If a total coliform-positive sample is at the end of the distribution system, or one away from the end of the distribution system, the State may waive the requirement to collect at least one repeat sample upstream or downstream of the original sampling site.


(3) The system must collect all repeat samples on the same day, except that the State may allow a system with a single service connection to collect the required set of repeat samples over a four-day period or to collect a larger volume repeat sample(s) in one or more sample containers of any size, as long as the total volume collected is at least 400 ml (300 ml for systems which collect more than one routine sample/month).


(4) If one or more repeat samples in the set is total coliform-positive, the public water system must collect an additional set of repeat samples in the manner specified in paragraphs (b) (1)-(3) of this section. The additional samples must be collected within 24 hours of being notified of the positive result, unless the State extends the limit as provided in paragraph (b)(1) of this section. The system must repeat this process until either total coliforms are not detected in one complete set of repeat samples or the system determines that the MCL for total coliforms in § 141.63 has been exceeded and notifies the State.


(5) If a system collecting fewer than five routine samples/month has one or more total coliform-positive samples and the State does not invalidate the sample(s) under paragraph (c) of this section, it must collect at least five routine samples during the next month the system provides water to the public, except that the State may waive this requirement if the conditions of paragraph (b)(5) (i) or (ii) of this section are met. The State cannot waive the requirement for a system to collect repeat samples in paragraphs (b) (1)-(4) of this section.


(i) The State may waive the requirement to collect five routine samples the next month the system provides water to the public if the State, or an agent approved by the State, performs a site visit before the end of the next month the system provides water to the public. Although a sanitary survey need not be performed, the site visit must be sufficiently detailed to allow the State to determine whether additional monitoring and/or any corrective action is needed. The State cannot approve an employee of the system to perform this site visit, even if the employee is an agent approved by the State to perform sanitary surveys.


(ii) The State may waive the requirement to collect five routine samples the next month the system provides water to the public if the State has determined why the sample was total coliform-positive and establishes that the system has corrected the problem or will correct the problem before the end of the next month the system serves water to the public. In this case, the State must document this decision to waive the following month’s additional monitoring requirement in writing, have it approved and signed by the supervisor of the State official who recommends such a decision, and make this document available to the EPA and public. The written documentation must describe the specific cause of the total coliform-positive sample and what action the system has taken and/or will take to correct this problem. The State cannot waive the requirement to collect five routine samples the next month the system provides water to the public solely on the grounds that all repeat samples are total coliform-negative. Under this paragraph, a system must still take at least one routine sample before the end of the next month it serves water to the public and use it to determine compliance with the MCL for total coliforms in § 141.63, unless the State has determined that the system has corrected the contamination problem before the system took the set of repeat samples required in paragraphs (b) (1)-(4) of this section, and all repeat samples were total coliform-negative.


(6) After a system collects a routine sample and before it learns the results of the analysis of that sample, if it collects another routine sample(s) from within five adjacent service connections of the initial sample, and the initial sample, after analysis, is found to contain total coliforms, then the system may count the subsequent sample(s) as a repeat sample instead of as a routine sample.


(7) Results of all routine and repeat samples not invalidated by the State must be included in determining compliance with the MCL for total coliforms in § 141.63.


(c) Invalidation of total coliform samples. A total coliform-positive sample invalidated under this paragraph (c) does not count towards meeting the minimum monitoring requirements of this section.


(1) The State may invalidate a total coliform-positive sample only if the conditions of paragraph (c)(1) (i), (ii), or (iii) of this section are met.


(i) The laboratory establishes that improper sample analysis caused the total coliform-positive result.


(ii) The State, on the basis of the results of repeat samples collected as required by paragraphs (b) (1) through (4) of this section, determines that the total coliform-positive sample resulted from a domestic or other non-distribution system plumbing problem. The State cannot invalidate a sample on the basis of repeat sample results unless all repeat sample(s) collected at the same tap as the original total coliform-positive sample are also total coliform-positive, and all repeat samples collected within five service connections of the original tap are total coliform-negative (e.g., a State cannot invalidate a total coliform-positive sample on the basis of repeat samples if all the repeat samples are total coliform-negative, or if the public water system has only one service connection).


(iii) The State has substantial grounds to believe that a total coliform-positive result is due to a circumstance or condition which does not reflect water quality in the distribution system. In this case, the system must still collect all repeat samples required under paragraphs (b) (1)-(4) of this section, and use them to determine compliance with the MCL for total coliforms in § 141.63. To invalidate a total coliform-positive sample under this paragraph, the decision with the rationale for the decision must be documented in writing, and approved and signed by the supervisor of the State official who recommended the decision. The State must make this document available to EPA and the public. The written documentation must state the specific cause of the total coliform-positive sample, and what action the system has taken, or will take, to correct this problem. The State may not invalidate a total coliform-positive sample solely on the grounds that all repeat samples are total coliform-negative.


(2) A laboratory must invalidate a total coliform sample (unless total coliforms are detected) if the sample produces a turbid culture in the absence of gas production using an analytical method where gas formation is examined (e.g., the Multiple-Tube Fermentation Technique), produces a turbid culture in the absence of an acid reaction in the Presence-Absence (P-A) Coliform Test, or exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter (e.g., Membrane Filter Technique). If a laboratory invalidates a sample because of such interference, the system must collect another sample from the same location as the original sample within 24 hours of being notified of the interference problem, and have it analyzed for the presence of total coliforms. The system must continue to re-sample within 24 hours and have the samples analyzed until it obtains a valid result. The State may waive the 24-hour time limit on a case-by-case basis.


(d) Sanitary surveys. (1)(i) Public water systems which do not collect five or more routine samples/month must undergo an initial sanitary survey by June 29, 1994, for community public water systems and June 29, 1999, for non-community water systems. Thereafter, systems must undergo another sanitary survey every five years, except that non-community water systems using only protected and disinfected ground water, as defined by the State, must undergo subsequent sanitary surveys at least every ten years after the initial sanitary survey. The State must review the results of each sanitary survey to determine whether the existing monitoring frequency is adequate and what additional measures, if any, the system needs to undertake to improve drinking water quality.


(ii) In conducting a sanitary survey of a system using ground water in a State having an EPA-approved wellhead protection program under section 1428 of the Safe Drinking Water Act, information on sources of contamination within the delineated wellhead protection area that was collected in the course of developing and implementing the program should be considered instead of collecting new information, if the information was collected since the last time the system was subject to a sanitary survey.


(2) Sanitary surveys must be performed by the State or an agent approved by the State. The system is responsible for ensuring the survey takes place.


(3) Sanitary surveys conducted by the State under the provisions of § 142.16(o)(2) of this chapter may be used to meet the sanitary survey requirements of this section.


(e) Fecal coliforms/Escherichia coli (E. coli) testing. (1) If any routine or repeat sample is total coliform-positive, the system must analyze that total coliform-positive culture medium to determine if fecal coliforms are present, except that the system may test for E. coli in lieu of fecal coliforms. If fecal coliforms or E. coli are present, the system must notify the State by the end of the day when the system is notified of the test result, unless the system is notified of the result after the State office is closed, in which case the system must notify the State before the end of the next business day.


(2) The State has the discretion to allow a public water system, on a case-by-case basis, to forgo fecal coliform or E. coli testing on a total coliform-positive sample if that system assumes that the total coliform-positive sample is fecal coliform-positive or E. coli-positive. Accordingly, the system must notify the State as specified in paragraph (e)(1) of this section and the provisions of § 141.63(b) apply.


(f) Analytical methodology. (1) The standard sample volume required for total coliform analysis, regardless of analytical method used, is 100 ml.


(2) Public water systems need only determine the presence or absence of total coliforms; a determination of total coliform density is not required.


(3) Public water systems must conduct total coliform analyses in accordance with one of the analytical methods in the following table or one of the alternative methods listed in appendix A to subpart C of this part.


Organism
Methodology
12
Citation
1
Total Coliforms
2		Total Coliform Fermentation Technique
3 4 5		9221A, B.
Total Coliform Membrane Filter Technique
6		9222A, B, C.
Presence-Absence (P-A) Coliform Test
5 7		9221D.
ONPG-MUG Test
8		9223.
Colisure Test.
9
E*Colite ® Test.
10
m-ColiBlue24 ® Test.
11
Readycult ® Coliforms 100 Presence/Absence Test.
13
Membrane Filter Technique using Chromocult ® Coliform Agar.
14
Colitag ® Test.
15

The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1, 6, 8, 9, 10 , 11, 13, 14 and 15 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800-426-4791. Documents may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW., EPA West, Room B102, Washington DC 20460 (Telephone: 202-566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.


1 Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998). American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. The cited methods published in any of these three editions may be used. In addition, the following online versions may also be used: 9221 A, B, D-99, 9222 A, B, C-97, and 9223 B-97. Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that may be used.


2 The time from sample collection to initiation of analysis may not exceed 30 hours. Systems are encouraged but not required to hold samples below 10 deg. C during transit.


3 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the system conducts at least 25 parallel tests between this medium and lauryl tryptose broth using the water normally tested, and this comparison demonstrates that the false-positive rate and false-negative rate for total coliform, using lactose broth, is less than 10 percent.


4 If inverted tubes are used to detect gas production, the media should cover these tubes at least one-half to two-thirds after the sample is added.


5 No requirement exists to run the completed phase on 10 percent of all total coliform-positive confirmed tubes.


6 MI agar also may be used. Preparation and use of MI agar is set forth in the article, “New medium for the simultaneous detection of total coliform and Escherichia coli in water” by Brenner, K.P., et. al., 1993, Appl. Environ. Microbiol. 59:3534-3544. Also available from the Office of Water Resource Center (RC-4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460, EPA/600/J-99/225. Verification of colonies is not required.


7 Six-times formulation strength may be used if the medium is filter-sterilized rather than autoclaved.


8 The ONPG-MUG Test is also known as the Autoanalysis Collect System.


9 A description of the Colisure Test, Feb 28, 1994, may be obtained from IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, Maine 04092. The Colisure Test may be read after an incubation time of 24 hours.


10 A description of the E*Colite ® Test, “Presence/Absence for Coliforms and E. Coli in Water,” Dec 21, 1997, is available from Charm Sciences, Inc., 36 Franklin Street, Malden, MA 02148-4120.


11 A description of the m-ColiBlue24 ® Test, Aug 17, 1999, is available from the Hach Company, 100 Dayton Avenue, Ames, IA 50010.


12 EPA strongly recommends that laboratories evaluate the false-positive and negative rates for the method(s) they use for monitoring total coliforms. EPA also encourages laboratories to establish false-positive and false-negative rates within their own laboratory and sample matrix (drinking water or source water) with the intent that if the method they choose has an unacceptable false-positive or negative rate, another method can be used. The Agency suggests that laboratories perform these studies on a minimum of 5% of all total coliform-positive samples, except for those methods where verification/confirmation is already required, e.g., the M-Endo and LES Endo Membrane Filter Tests, Standard Total Coliform Fermentation Technique, and Presence-Absence Coliform Test. Methods for establishing false-positive and negative-rates may be based on lactose fermentation, the rapid test for β-galactosidase and cytochrome oxidase, multi-test identification systems, or equivalent confirmation tests. False-positive and false-negative information is often available in published studies and/or from the manufacturer(s).


13 The Readycult ® Coliforms 100 Presence/Absence Test is described in the document, “Readycult ® Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichla coli in Finished Waters”, November 2000, Version 1.0, available from EM Science (an affiliate of Merck KGgA, Darmstadt Germany), 480 S. Democrat Road, Gibbstown, NJ 08027-1297. Telephone number is (800) 222-0342, e-mail address is: [email protected].


14 Membrane Filter Technique using Chromocult ® Coliform Agar is described in the document, “Chromocult ® Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform Bacteria and Escherichla coli in Finished Waters”, November 2000, Version 1.0, available from EM Science (an affiliate of Merck KGgA, Darmstadt Germany), 480 S. Democrat Road, Gibbstown, NJ 08027-1297. Telephone number is (800) 222-0342, e-mail address is: [email protected].


15 Colitag ® product for the determination of the presence/absence of total coliforms and E. coli is described in “Colitag ® Product as a Test for Detection and Identification of Coliforms and E. coli Bacteria in Drinking Water and Source Water as Required in National Primary Drinking Water Regulations,” August 2001, available from CPI International, Inc., 5580 Skylane Blvd., Santa Rosa, CA, 95403, telephone (800) 878-7654, Fax (707) 545-7901, Internet address http://www.cpiinternational.com.


(4) [Reserved]


(5) Public water systems must conduct fecal coliform analysis in accordance with the following procedure. When the MTF Technique or Presence-Absence (PA) Coliform Test is used to test for total coliforms, shake the lactose-positive presumptive tube or P-A vigorously and transfer the growth with a sterile 3-mm loop or sterile applicator stick into brilliant green lactose bile broth and EC medium to determine the presence of total and fecal coliforms, respectively. For EPA-approved analytical methods which use a membrane filter, transfer the total coliform-positive culture by one of the following methods: remove the membrane containing the total coliform colonies from the substrate with a sterile forceps and carefully curl and insert the membrane into a tube of EC medium (the laboratory may first remove a small portion of selected colonies for verification), swab the entire membrane filter surface with a sterile cotton swab and transfer the inoculum to EC medium (do not leave the cotton swab in the EC medium), or inoculate individual total coliform-positive colonies into EC Medium. Gently shake the inoculated tubes of EC medium to insure adequate mixing and incubate in a waterbath at 44.5 ±0.2 °C for 24 ±2 hours. Gas production of any amount in the inner fermentation tube of the EC medium indicates a positive fecal coliform test. The preparation of EC medium is described in Method 9221E (paragraph 1a) in Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), and 20th edition (1998); the cited method in any one of these three editions may be used. Public water systems need only determine the presence or absence of fecal coliforms; a determination of fecal coliform density is not required.


(6) Public water systems must conduct analysis of Escherichia coli in accordance with one of the following analytical methods or one of the alternative methods listed in appendix A to subpart C of this part.


(i) EC medium supplemented with 50 µg/mL of 4-methylumbelliferyl-beta-D-glucuronide (MUG) (final concentration), as described in Method 9222G in Standard Methods for the Examination of Water and Wastewater, 19th edition (1995) and 20th edition (1998). Either edition may be used. Alternatively, the 18th edition (1992) may be used if at least 10 mL of EC medium, as described in paragraph (f)(5) of this section, is supplemented with 50 µg/mL of MUG before autoclaving. The inner inverted fermentation tube may be omitted. If the 18th edition is used, apply the procedure in paragraph (f)(5) of this section for transferring a total coliform-positive culture to EC medium supplemented with MUG, incubate the tube at 44.5 ±0.2 °C for 24 ±2 hours, and then observe fluorescence with an ultraviolet light (366 nm) in the dark. If fluorescence is visible, E. coli are present.


(ii) Nutrient agar supplemented with 100 µg/mL of 4-methylumbelliferyl-beta-D-glucuronide (MUG) (final concentration), as described in Method 9222G in Standard Methods for the Examination of Water and Wastewater, 19th edition (1995) and 20th edition (1998). Either edition may be used for determining if a total coliform-positive sample, as determined by a membrane filter technique, contains E. coli. Alternatively, the 18th edition (1992) may be used if the membrane filter containing a total coliform-positive colony(ies) is transferred to nutrient agar, as described in Method 9221B (paragraph 3) of Standard Methods (18th edition), supplemented with 100 µg/mL of MUG. If the 18th edition is used, incubate the agar plate at 35 °C for 4 hours and then observe the colony(ies) under ultraviolet light (366 nm) in the dark for fluorescence. If fluorescence is visible, E. coli are present.


(iii) Minimal Medium ONPG-MUG (MMO-MUG) Test, as set forth in the article “National Field Evaluation of a Defined Substrate Method for the Simultaneous Detection of Total Coliforms and Escherichia coli from Drinking Water: Comparison with Presence-Absence Techniques” (Edberg et al.), Applied and Environmental Microbiology, Volume 55, pp. 1003-1008, April 1989. (Note: The Autoanalysis Colilert System is an MMO-MUG test). If the MMO-MUG test is total coliform-positive after a 24-hour incubation, test the medium for fluorescence with a 366-nm ultraviolet light (preferably with a 6-watt lamp) in the dark. If fluorescence is observed, the sample is E. coli-positive. If fluorescence is questionable (cannot be definitively read) after 24 hours incubation, incubate the culture for an additional four hours (but not to exceed 28 hours total), and again test the medium for fluorescence. The MMO-MUG Test with hepes buffer in lieu of phosphate buffer is the only approved formulation for the detection of E. coli.


(iv) The Colisure Test. A description of the Colisure Test may be obtained from the Millipore Corporation, Technical Services Department, 80 Ashby Road, Bedford, MA 01730.


(v) The membrane filter method with MI agar, a description of which is cited in footnote 6 to the table in paragraph (f)(3) of this section.


(vi) E*Colite ® Test, a description of which is cited in footnote 10 to the table at paragraph (f)(3) of this section.


(vii) m-ColiBlue24 ® Test, a description of which is cited in footnote 11 to the table in paragraph (f)(3) of this section.


(viii) Readycult ® Coliforms 100 Presence/Absence Test, a description of which is cited in footnote 13 to the table at paragraph (f)(3) of this section.


(ix) Membrane Filter Technique using Chromocult ® Coliform Agar, a description of which is cited in footnote 14 to the table at paragraph (f)(3) of this section.


(x) Colitag ®, a description of which is cited in footnote 15 to the table at paragraph (f)(3) of this section.


(7) As an option to paragraph (f)(6)(iii) of this section, a system with a total coliform-positive, MUG-negative, MMO-MUG test may further analyze the culture for the presence of E. coli by transferring a 0.1 ml, 28-hour MMO-MUG culture to EC Medium + MUG with a pipet. The formulation and incubation conditions of EC Medium + MUG, and observation of the results are described in paragraph (f)(6)(i) of this section.


(8) The following materials are incorporated by reference in this section with the approval of the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the analytical methods cited in Standard Methods for the Examination of Water and Wastewater (18th, 19th, and 20th editions) may be obtained from the American Public Health Association et al.; 1015 Fifteenth Street, NW., Washington, DC 20005-2605. Copies of the MMO-MUG Test, as set forth in the article “National Field Evaluation of a Defined Substrate Method for the Simultaneous Enumeration of Total Coliforms and Escherichia coli from Drinking Water: Comparison with the Standard Multiple Tube Fermentation Method” (Edberg et al.) may be obtained from the American Water Works Association Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235. Copies of the MMO-MUG Test as set forth in the article “National Field Evaluation of a Defined Substrate Method for the Simultaneous Enumeration of Total Coliforms and Escherichia coli from Drinking Water: Comparison with the Standard Multiple Tube Fermentation Method” (Edberg et al.) may be obtained from the American Water Works Association Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235. A description of the Colisure Test may be obtained from the Millipore Corp., Technical Services Department, 80 Ashby Road, Bedford, MA 01730. Copies may be inspected at EPA’s Drinking Water Docket; 401 M St., SW.; Washington, DC 20460, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.


(g) Response to violation. (1) A public water system which has exceeded the MCL for total coliforms in § 141.63 must report the violation to the State no later than the end of the next business day after it learns of the violation, and notify the public in accordance with subpart Q.


(2) A public water system which has failed to comply with a coliform monitoring requirement, including the sanitary survey requirement, must report the monitoring violation to the State within ten days after the system discovers the violation, and notify the public in accordance with subpart Q.


(h) The provisions of paragraphs (a) and (d) of this section are applicable until March 31, 2016. The provisions of paragraphs (b), (c), (e), (f), and (g) of this section are applicable until all required repeat monitoring under paragraph (b) of this section and fecal coliform or E. coli testing under paragraph (e) of this section that was initiated by a total coliform-positive sample taken before April 1, 2016 is completed, as well as analytical method, reporting, recordkeeping, public notification, and consumer confidence report requirements associated with that monitoring and testing. Beginning April 1, 2016, the provisions of subpart Y of this part are applicable, with systems required to begin regular monitoring at the same frequency as the system-specific frequency required on March 31, 2016.


[54 FR 27562, June 29, 1989]


Editorial Note:For Federal Register citations affecting § 141.21, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

§ 141.22 Turbidity sampling and analytical requirements.

The requirements in this section apply to unfiltered systems until December 30, 1991, unless the State has determined prior to that date, in writing pursuant to section 1412(b)(7)(iii), that filtration is required. The requirements in this section apply to filtered systems until June 29, 1993. The requirements in this section apply to unfiltered systems that the State has determined, in writing pursuant to section 1412(b)(7)(C)(iii), must install filtration, until June 29, 1993, or until filtration is installed, whichever is later.


(a) Samples shall be taken by suppliers of water for both community and non-community water systems at a representative entry point(s) to the water distribution system at least once per day, for the purposes of making turbidity measurements to determine compliance with § 141.13. If the State determines that a reduced sampling frequency in a non-community will not pose a risk to public health, it can reduce the required sampling frequency. The option of reducing the turbidity frequency shall be permitted only in those public water systems that practice disinfection and which maintain an active residual disinfectant in the distribution system, and in those cases where the State has indicated in writing that no unreasonable risk to health existed under the circumstances of this option. Turbidity measurements shall be made as directed in § 141.74(a)(1).


(b) If the result of a turbidity analysis indicates that the maximum allowable limit has been exceeded, the sampling and measurement shall be confirmed by resampling as soon as practicable and preferably within one hour. If the repeat sample confirms that the maximum allowable limit has been exceeded, the supplier of water shall report to the State within 48 hours. The repeat sample shall be the sample used for the purpose of calculating the monthly average. If the monthly average of the daily samples exceeds the maximum allowable limit, or if the average of two samples taken on consecutive days exceeds 5 TU, the supplier of water shall report to the State and notify the public as directed in § 141.31 and subpart Q.


(c) Sampling for non-community water systems shall begin within two years after the effective date of this part.


(d) The requirements of this § 141.22 shall apply only to public water systems which use water obtained in whole or in part from surface sources.


(e) The State has the authority to determine compliance or initiate enforcement action based upon analytical results or other information compiled by their sanctioned representatives and agencies.


[40 FR 59570, Dec. 24, 1975, as amended at 45 FR 57344, Aug. 27, 1980; 47 FR 8998, Mar. 3, 1982; 47 FR 10998, Mar. 12, 1982; 54 FR 27527, June 29, 1989; 59 FR 62466, Dec. 5, 1994; 65 FR 26022, May 4, 2000]


§ 141.23 Inorganic chemical sampling and analytical requirements.

Community water systems shall conduct monitoring to determine compliance with the maximum contaminant levels specified in § 141.62 in accordance with this section. Non-transient, non-community water systems shall conduct monitoring to determine compliance with the maximum contaminant levels specified in § 141.62 in accordance with this section. Transient, non-community water systems shall conduct monitoring to determine compliance with the nitrate and nitrite maximum contaminant levels in §§ 141.11 and 141.62 (as appropriate) in accordance with this section.


(a) Monitoring shall be conducted as follows:


(1) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point) beginning in the initial compliance period. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.


(2) Surface water systems shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the distribution system at a point which is representative of each source after treatment (hereafter called a sampling point) beginning in the initial compliance period. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.



Note:

For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.


(3) If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water is representative of all sources being used).


(4) The State may reduce the total number of samples which must be analyzed by allowing the use of compositing. Composite samples from a maximum of five samples are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory.


(i) If the concentration in the composite sample is greater than or equal to one-fifth of the MCL of any inorganic chemical, then a follow-up sample must be taken within 14 days at each sampling point included in the composite. These samples must be analyzed for the contaminants which exceeded one-fifth of the MCL in the composite sample. Detection limits for each analytical method and MCLs for each inorganic contaminant are the following:


Detection Limits for Inorganic Contaminants

Contaminant
MCL (mg/l)
Methodology
Detection limit (mg/l)
Antimony0.006Atomic Absorption; Furnace0.003
Atomic Absorption; Platform0.0008
5
ICP-Mass Spectrometry0.0004
Hydride-Atomic Absorption0.001
Arsenic0.010
6		Atomic Absorption; Furnace0.001
Atomic Absorption; Platform—Stabilized Temperature0.0005
7
Atomic Absorption; Gaseous Hydride0.001
ICP-Mass Spectrometry0.0014
8
Asbestos7 MFL
1		Transmission Electron Microscopy0.01 MFL
Barium2Atomic Absorption; furnace technique0.002
Atomic Absorption; direct aspiration0.1
Inductively Coupled Plasma0.002 (0.001)
Beryllium0.004Atomic Absorption; Furnace0.0002
Atomic Absorption; Platform0.00002
5
Inductively Coupled Plasma
2		0.0003
ICP-Mass Spectrometry0.0003
Cadmium0.005Atomic Absorption; furnace technique0.0001
Inductively Coupled Plasma0.001
Chromium0.1Atomic Absorption; furnace technique0.001
Inductively Coupled Plasma0.007 (0.001)
Cyanide0.2Distillation, Spectrophotometric
3		0.02
Distillation, Automated, Spectrophotometric
3		0.005
Distillation, Amenable, Spectrophotometric
4		0.02
Distillation, Selective Electrode
3 4		0.05
UV, Distillation, Spectrophotometric
9		0.0005
Micro Distillation, Flow Injection, Spectrophotometric
3		0.0006
Ligand Exchange with Amperometry
4		0.0005
Mercury0.002Manual Cold Vapor Technique0.0002
Automated Cold Vapor Technique0.0002
NickelxlAtomic Absorption; Furnace0.001
Atomic Absorption; Platform0.0006
5
Inductively Coupled Plasma
2		0.005
ICP-Mass Spectrometry0.0005
Nitrate10 (as N)Manual Cadmium Reduction0.01
Automated Hydrazine Reduction0.01
Automated Cadmium Reduction0.05
Ion Selective Electrode1
Ion Chromatography0.01
Capillary Ion Electrophoresis0.076
Nitrite1 (as N)Spectrophotometric0.01
Automated Cadmium Reduction0.05
Manual Cadmium Reduction0.01
Ion Chromatography0.004
Capillary Ion Electrophoresis0.103
Selenium0.05Atomic Absorption; furnace0.002
Atomic Absorption; gaseous hydride0.002
Thallium0.002Atomic Absorption; Furnace0.001
Atomic Absorption; Platform0.0007
5
ICP-Mass Spectrometry0.0003


1 MFL = million fibers per liter >10 µm.


2 Using a 2X preconcentration step as noted in Method 200.7. Lower MDLs may be achieved when using a 4X preconcentration.


3 Screening method for total cyanides.


4 Measures “free” cyanides when distillation, digestion, or ligand exchange is omitted.


5 Lower MDLs are reported using stabilized temperature graphite furnace atomic absorption.


6 The value for arsenic is effective January 23, 2006. Unit then, the MCL is 0.05 mg/L.


7 The MDL reported for EPA method 200.9 (Atomic Absorption; Platform—Stablized Temperature) was determined using a 2x concentration step during sample digestion. The MDL determined for samples analyzed using direct analyses (i.e., no sample digestion) will be higher. Using multiple depositions, EPA 200.9 is capable of obtaining MDL of 0.0001 mg/L.


8 Using selective ion monitoring, EPA Method 200.8 (ICP-MS) is capable of obtaining a MDL of 0.0001 mg/L.


9 Measures total cyanides when UV-digestor is used, and “free” cyanides when UV-digestor is bypassed.


(ii) If the population served by the system is >3,300 persons, then compositing may only be permitted by the State at sampling points within a single system. In systems serving ≤3,300 persons, the State may permit compositing among different systems provided the 5-sample limit is maintained.


(iii) If duplicates of the original sample taken from each sampling point used in the composite sample are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the State within 14 days after completing analysis of the composite sample, provided the holding time of the sample is not exceeded.


(5) The frequency of monitoring for asbestos shall be in accordance with paragraph (b) of this section: the frequency of monitoring for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium and thallium shall be in accordance with paragraph (c) of this section; the frequency of monitoring for nitrate shall be in accordance with paragraph (d) of this section; and the frequency of monitoring for nitrite shall be in accordance with paragraph (e) of this section.


(b) The frequency of monitoring conducted to determine compliance with the maximum contaminant level for asbestos specified in § 141.62(b) shall be conducted as follows:


(1) Each community and non-transient, non-community water system is required to monitor for asbestos during the first three-year compliance period of each nine-year compliance cycle beginning in the compliance period starting January 1, 1993.


(2) If the system believes it is not vulnerable to either asbestos contamination in its source water or due to corrosion of asbestos-cement pipe, or both, it may apply to the State for a waiver of the monitoring requirement in paragraph (b)(1) of this section. If the State grants the waiver, the system is not required to monitor.


(3) The State may grant a waiver based on a consideration of the following factors:


(i) Potential asbestos contamination of the water source, and


(ii) The use of asbestos-cement pipe for finished water distribution and the corrosive nature of the water.


(4) A waiver remains in effect until the completion of the three-year compliance period. Systems not receiving a waiver must monitor in accordance with the provisions of paragraph (b)(1) of this section.


(5) A system vulnerable to asbestos contamination due solely to corrosion of asbestos-cement pipe shall take one sample at a tap served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.


(6) A system vulnerable to asbestos contamination due solely to source water shall monitor in accordance with the provision of paragraph (a) of this section.


(7) A system vulnerable to asbestos contamination due both to its source water supply and corrosion of asbestos-cement pipe shall take one sample at a tap served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.


(8) A system which exceeds the maximum contaminant levels as determined in § 141.23(i) of this section shall monitor quarterly beginning in the next quarter after the violation occurred.


(9) The State may decrease the quarterly monitoring requirement to the frequency specified in paragraph (b)(1) of this section provided the State has determined that the system is reliably and consistently below the maximum contaminant level. In no case can a State make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface (or combined surface/ground) water system takes a minimum of four quarterly samples.


(10) If monitoring data collected after January 1, 1990 are generally consistent with the requirements of § 141.23(b), then the State may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.


(c) The frequency of monitoring conducted to determine compliance with the maximum contaminant levels in § 141.62 for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium and thallium shall be as follows:


(1) Groundwater systems shall take one sample at each sampling point during each compliance period. Surface water systems (or combined surface/ground) shall take one sample annually at each sampling point.


(2) The system may apply to the State for a waiver from the monitoring frequencies specified in paragraph (c)(1) of this section. States may grant a public water system a waiver for monitoring of cyanide, provided that the State determines that the system is not vulnerable due to lack of any industrial source of cyanide.


(3) A condition of the waiver shall require that a system shall take a minimum of one sample while the waiver is effective. The term during which the waiver is effective shall not exceed one compliance cycle (i.e., nine years).


(4) The State may grant a waiver provided surface water systems have monitored annually for at least three years and groundwater systems have conducted a minimum of three rounds of monitoring. (At least one sample shall have been taken since January 1, 1990). Both surface and groundwater systems shall demonstrate that all previous analytical results were less than the maximum contaminant level. Systems that use a new water source are not eligible for a waiver until three rounds of monitoring from the new source have been completed.


(5) In determining the appropriate reduced monitoring frequency, the State shall consider:


(i) Reported concentrations from all previous monitoring;


(ii) The degree of variation in reported concentrations; and


(iii) Other factors which may affect contaminant concentrations such as changes in groundwater pumping rates, changes in the system’s configuration, changes in the system’s operating procedures, or changes in stream flows or characteristics.


(6) A decision by the State to grant a waiver shall be made in writing and shall set forth the basis for the determination. The determination may be initiated by the State or upon an application by the public water system. The public water system shall specify the basis for its request. The State shall review and, where appropriate, revise its determination of the appropriate monitoring frequency when the system submits new monitoring data or when other data relevant to the system’s appropriate monitoring frequency become available.


(7) Systems which exceed the maximum contaminant levels as calculated in § 141.23(i) of this section shall monitor quarterly beginning in the next quarter after the violation occurred.


(8) The State may decrease the quarterly monitoring requirement to the frequencies specified in paragraphs (c)(1) and (c)(2) of this section provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case can a State make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.


(9) All new systems or systems that use a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the State. The system must also comply with the initial sampling frequencies specified by the State to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.


(d) All public water systems (community; non-transient, non-community; and transient, non-community systems) shall monitor to determine compliance with the maximum contaminant level for nitrate in § 141.62.


(1) Community and non-transient, non-community water systems served by groundwater systems shall monitor annually beginning January 1, 1993; systems served by surface water shall monitor quarterly beginning January 1, 1993.


(2) For community and non-transient, non-community water systems, the repeat monitoring frequency for groundwater systems shall be quarterly for at least one year following any one sample in which the concentration is ≥50 percent of the MCL. The State may allow a groundwater system to reduce the sampling frequency to annually after four consecutive quarterly samples are reliably and consistently less than the MCL.


(3) For community and non-transient, non-community water systems, the State may allow a surface water system to reduce the sampling frequency to annually if all analytical results from four consecutive quarters are

(4) Each transient non-community water system shall monitor annually beginning January 1, 1993.


(5) After the initial round of quarterly sampling is completed, each community and non-transient non-community system which is monitoring annually shall take subsequent samples during the quarter(s) which previously resulted in the highest analytical result.


(e) All public water systems (community; non-transient, non-community; and transient, non-community systems) shall monitor to determine compliance with the maximum contaminant level for nitrite in § 141.62(b).


(1) All public water systems shall take one sample at each sampling point in the compliance period beginning January 1, 1993 and ending December 31, 1995.


(2) After the initial sample, systems where an analytical result for nitrite is

(3) For community, non-transient, non-community, and transient non-community water systems, the repeat monitoring frequency for any water system shall be quarterly for at least one year following any one sample in which the concentration is ≥50 percent of the MCL. The State may allow a system to reduce the sampling frequency to annually after determining the system is reliably and consistently less than the MCL.


(4) Systems which are monitoring annually shall take each subsequent sample during the quarter(s) which previously resulted in the highest analytical result.


(f) Confirmation samples:


(1) Where the results of sampling for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium indicate an exceedance of the maximum contaminant level, the State may require that one additional sample be collected as soon as possible after the initial sample was taken (but not to exceed two weeks) at the same sampling point.


(2) Where nitrate or nitrite sampling results indicate an exceedance of the maximum contaminant level, the system shall take a confirmation sample within 24 hours of the system’s receipt of notification of the analytical results of the first sample. Systems unable to comply with the 24-hour sampling requirement must immediately notify persons served by the public water system in accordance with § 141.202 and meet other Tier 1 public notification requirements under subpart Q of this part. Systems exercising this option must take and analyze a confirmation sample within two weeks of notification of the analytical results of the first sample.


(3) If a State-required confirmation sample is taken for any contaminant, then the results of the initial and confirmation sample shall be averaged. The resulting average shall be used to determine the system’s compliance in accordance with paragraph (i) of this section. States have the discretion to delete results of obvious sampling errors.


(g) The State may require more frequent monitoring than specified in paragraphs (b), (c), (d) and (e) of this section or may require confirmation samples for positive and negative results at its discretion.


(h) Systems may apply to the State to conduct more frequent monitoring than the minimum monitoring frequencies specified in this section.


(i) Compliance with § 141.11 or § 141.62(b) (as appropriate) shall be determined based on the analytical result(s) obtained at each sampling point.


(1) For systems which are conducting monitoring at a frequency greater than annual, compliance with the maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium is determined by a running annual average at any sampling point. If the average at any sampling point is greater than the MCL, then the system is out of compliance. If any one sample would cause the annual average to be exceeded, then the system is out of compliance immediately. Any sample below the method detection limit shall be calculated at zero for the purpose of determining the annual average. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.


(2) For systems which are monitoring annually, or less frequently, the system is out of compliance with the maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium if the level of a contaminant is greater than the MCL. If confirmation samples are required by the State, the determination of compliance will be based on the annual average of the initial MCL exceedance and any State-required confirmation samples. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.


(3) Compliance with the maximum contaminant levels for nitrate and nitrate is determined based on one sample if the levels of these contaminants are below the MCLs. If the levels of nitrate and/or nitrite exceed the MCLs in the initial sample, a confirmation sample is required in accordance with paragraph (f)(2) of this section, and compliance shall be determined based on the average of the initial and confirmation samples.


(4) Arsenic sampling results will be reported to the nearest 0.001 mg/L.


(j) Each public water system shall monitor at the time designated by the State during each compliance period.


(k) Inorganic analysis:


(1) Analysis for the following contaminants shall be conducted in accordance with the methods in the following table, or the alternative methods listed in appendix A to subpart C of this part, or their equivalent as determined by EPA. Criteria for analyzing arsenic, barium, beryllium, cadmium, calcium, chromium, copper, lead, nickel, selenium, sodium, and thallium with digestion or directly without digestion, and other analytical test procedures are contained in Technical Notes on Drinking Water Methods, EPA-600/R-94-173, October 1994. This document is available from the National Service Center for Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 45242-0419 or http://www.epa.gov/nscep/.


Contaminant
Methodology
13
EPA
ASTM
3
SM
4 (18th, 19th ed.)
SM
4 (20th ed.)
SM Online
22
Other
1. AlkalinityTitrimetricD1067-92, 02 B2320 B2320 B2320 B-97
Electrometric titrationI-1030-85
5
2. AntimonyInductively Coupled Plasma (ICP)—Mass Spectrometry200.8
2
Hydride-Atomic AbsorptionD3697-92, 02
Atomic Absorption; Platform200.9
2
Atomic Absorption; Furnace3113 B3113 B-99
3. Arsenic
14		ICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Atomic Absorption; FurnaceD2972-97, 03 C3113 B3113 B-99
Hydride Atomic AbsorptionD1972-97, 03 B3114 B3114 B-97
4. AsbestosTransmission Electron Microscopy100.1
9
Transmission Electron Microscopy100.2
10
5. BariumInductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
ICP-Mass Spectrometry200.8
2
Atomic Absorption; Direct3111D3111 D-99
Atomic Absorption; Furnace3113 B3113 B-99
6. BerylliumInductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
ICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Atomic Absorption; FurnaceD3645-97, 03 B3113 B3113 B-99
7. CadmiumInductively Coupled Plasma200.7
2
ICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Atomic Absorption; Furnace3113 B3113 B-99
8. CalciumEDTA titrimetricD511-93, 03 A3500-Ca D3500-Ca B3500-Ca B-97
Atomic Absorption; Direct AspirationD511-93, 03 B3111 B3111 B-99
Inductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
Ion ChromatographyD6919-03
9. ChromiumInductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
ICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Atomic Absorption; Furnace3113 B3113 B-99
10. CopperAtomic Absorption; FurnaceD1688-95, 02 C3113 B3113 B-99
Atomic Absorption; Direct AspirationD1688-95, 02 A3111 B3111 B-99
Inductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
ICP-Mass spectrometry200.8
2
Atomic Absorption; Platform200.9
2
11. ConductivityConductanceD1125-95 (Reapproved 1999) A2510 B2510 B2510 B-97
12. CyanideManual Distillation followed byD2036-98 A4500-CN− C4500-CN− C
Spectrophotometric, AmenableD2036-98 B4500-CN− G4500-CN− G4500-CN− G-99
Spectro-photometric ManualD2036-98 A4500-CN− E4500-CN− E4500-CN− E-99I-3300-85
5
Spectro-photometric Semi-automated335.4
6
Selective Electrode4500-CN− F4500-CN− F4500-CN− F-99
UV, Distillation, SpectrophotometricKelada-01
17
Micro Distillation, Flow Injection, SpectrophotometricQuikChem 10-204-00-1-X
18
Ligand Exchange and Amperometry
21		D6888-04OIA-1677, DW
20
13. FluorideIon Chromatography300.0
6, 300.1
19		D4327-97, 034110 B4110 B4110 B-00
Manual Distill.; Color. SPADNS4500-F− B, D4500-F− B, D4500-F− B, D-97
Manual ElectrodeD1179-93, 99 B4500-F− C4500-F− C4500-F− C-97
Automated Electrode380-75WE
11
Automated Alizarin4500-F− E4500-F− E4500-F− E-97129-71W
11
Capillary Ion ElectrophoresisD6508, Rev. 2
23
14. LeadAtomic Absorption; FurnaceD3559-96, 03 D3113 B3113 B-99
ICP-Mass spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Differential Pulse Anodic Stripping VoltametryMethod 1001
16
15. MagnesiumAtomic AbsorptionD511-93, 03 B3111 B3111 B-99
ICP200.7
2		3120 B3120 B3120 B-99
Complexation Titrimetric MethodsD511-93, 03 A3500-Mg E3500-Mg B3500-Mg B-97
Ion ChromatographyD6919-03
16. MercuryManual, Cold Vapor245.1
2		D3223-97, 023112 B3112 B-99
Automated, Cold Vapor245.2
1
ICP-Mass Spectrometry200.8
2
17. NickelInductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
ICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Atomic Absorption; Direct3111 B3111 B-99
Atomic Absorption; Furnace3113 B3113 B-99
18. NitrateIon Chromatography300.0
6, 300.1
19		D4327-97, 034110 B4110 B4110 B-00B-1011
8
Automated Cadmium Reduction353.2
6		D3867-90 A4500-NO3− F4500-NO3− F4500-NO3− F-00
Ion Selective Electrode4500-NO3− D4500-NO3− D4500-NO3− D-00601
7
Manual Cadmium ReductionD3867-90 B4500-NO3− E4500-NO3− E4500-NO3− E-00
Capillary Ion ElectrophoresisD6508-00.
19. NitriteIon Chromatography300.0
6, 300.1
19		D4327-97, 034110 B4110 B4110 B-00B-1011
8
Automated Cadmium Reduction353.2
6		D3867-90 A4500-NO3− F4500-NO3− F4500-NO3− F-00
Manual Cadmium ReductionD3867-90 B4500-NO3− E4500-NO3− E4500-NO3− E-00
Spectrophotometric4500-NO2− B4500-NO2− B4500-NO2− B-00
Capillary Ion ElectrophoresisD6508-00
20. Ortho-phosphateColorimetric, Automated, Ascorbic Acid365.1
6		4500-P F4500-P F
Colorimetric, ascorbic acid, single reagentD515-88 A4500-P E4500-P E
Colorimetric Phosphomolybdate; Automated-segmented flow; Automated DiscreteI-1601-85
5

I-2601-90
5

I-2598-85
5
Ion Chromatography300.0
6, 300.1
19		D4327-97, 034110 B4110 B4110 B-00
Capillary Ion ElectrophoresisD6508-00
21. pHElectrometric150.1, 150.2
1		D1293-95, 994500-H
+ B		4500-H
+ B		4500-H
+ B-00
22. SeleniumHydride-Atomic AbsorptionD3859-98, 03 A3114 B3114 B-97
ICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2
Atomic Absorption; FurnaceD3859-98, 03 B3113 B3113 B-99
23. SilicaColorimetric, Molybdate BlueI-1700-85
5
Automated-segmented FlowI-2700-85
5
ColorimetricD859-94, 00
Molybdosilicate4500-Si D4500-SiO2 C4500-SiO2 C-97
Heteropoly blue4500-Si E4500-SiO2 D4500-SiO2 D-97
Automated for Molybdate-reactive Silica4500-Si F4500-SiO2 E4500-SiO2 E-97
Inductively Coupled Plasma200.7
2		3120 B3120 B3120 B-99
24. SodiumInductively Coupled Plasma200.7
2
Atomic Absorption; Direct Aspiration3111 B3111 B-99
Ion ChromatographyD6919-03
25. TemperatureThermometric255025502550-00
26. ThalliumICP-Mass Spectrometry200.8
2
Atomic Absorption; Platform200.9
2

The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1-11, 16-20, and 22-23 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800-426-4791. Documents may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW., Room 3334, Washington, DC 20460 (Telephone: 202-566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.


1 “Methods for Chemical Analysis of Water and Wastes,” EPA/600/4-79/020, March 1983. Available at NTIS, PB84-128677.


2 “Methods for the Determination of Metals in Environmental Samples—Supplement I,” EPA/600/R-94/111, May 1994. Available at NTIS, PB95-125472.


3 Annual Book of ASTM Standards, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428, http://www.astm.org.; Annual Book of ASTM Standards 1994, Vols. 11.01 and 11.02; Annual Book of ASTM Standards 1996, Vols. 11.01 and 11.02; Annual Book of ASTM Standards 1999, Vols. 11.01 and 11.02; Annual Book of ASTM Standards 2003, Vols. 11.01 and 11.02.


4 Standard Methods for the Examination of Water and Wastewater, American Public Health Association, 800 I Street NW., Washington, DC 20001-3710; Standard Methods for the Examination of Water and Wastewater, 18th edition (1992); Standard Methods for the Examination of Water and Wastewater, 19th edition (1995); Standard Methods for the Examination of Water and Wastewater, 20th edition (1998).The following methods from this edition cannot be used: 3111 B, 3111 D, 3113 B, and 3114 B.


5 U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225-0425; Methods for Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water and Fluvial Sediment, Open File Report 93-125, 1993; Techniques of Water Resources Investigation of the U.S. Geological Survey, Book 5, Chapter A-1, 3rd edition, 1989.


6 “Methods for the Determination of Inorganic Substances in Environmental Samples,” EPA/600/R-93/100, August 1993. Available as Technical Report PB94-120821 at National Technical Information Service (NTIS), 5301 Shawnee Road, Alexandria, VA 22312. http://www.ntis.gov.


7 The procedure shall be done in accordance with the Technical Bulletin 601 “Standard Method of Test for Nitrate in Drinking Water,” July 1994, PN 221890-001, Analytical Technology, Inc. Copies may be obtained from ATI Orion, 529 Main Street, Boston, MA 02129.


8 Method B-1011. “Waters Test Method for Determination of Nitrite/Nitrate in Water Using Single Column Ion Chromatography,” August, 1987. Copies may be obtained from Waters Corporation, Technical Services Division, 34 Maple Street, Milford, MA 01757, Telephone: 508/482-2963, Fax: 508/482-4056.


9 Method 100.1, “Analytical Method For Determination of Asbestos Fibers in Water,” EPA/600/4-83/043, EPA, September 1983. Available at NTIS, PB83-260471.


10 Method 100.2, “Determination of Asbestos Structure Over 10-μm In Length In Drinking Water,” EPA/600/R-94/134, June 1994. Available at NTIS, PB94-201902.


11 Industrial Method No. 129-71W, “Fluoride in Water and Wastewater,” December 1972, and Method No. 380-75WE, “Fluoride in Water and Wastewater,” February 1976, Technicon Industrial Systems. Copies may be obtained from Bran & Luebbe, 1025 Busch Parkway, Buffalo Grove, IL 60089.


12 Unfiltered, no digestion or hydrolysis.


13 Because MDLs reported in EPA Methods 200.7 and 200.9 were determined using a 2x preconcentration step during sample digestion, MDLs determined when samples are analyzed by direct analysis (i.e., no sample digestion) will be higher. For direct analysis of cadmium and arsenic by Method 200.7, and arsenic by Method 3120 B, sample preconcentration using pneumatic nebulization may be required to achieve lower detection limits. Preconcentration may also be required for direct analysis of antimony, lead, and thallium by Method 200.9; antimony and lead by Method 3113 B; and lead by Method D3559-90D, unless multiple in-furnace depositions are made.


14 If ultrasonic nebulization is used in the determination of arsenic by Method 200.8, the arsenic must be in the pentavalent state to provide uniform signal response. For direct analysis of arsenic with Method 200.8 using ultrasonic nebulization, samples and standards must contain 1 mg/L of sodium hypochlorite.


15 [Reserved]


16 The description for Method Number 1001 for lead is available from Palintest, LTD, 21 Kenton Lands Road, P.O. Box 18395, Erlanger, KY 41018. Or from the Hach Company, P.O. Box 389, Loveland, CO 80539.


17 The description for the Kelada-01 Method, “Kelada Automated Test Methods for Total Cyanide, Acid Dissociable Cyanide, And Thiocyanate,” Revision 1.2, August 2001, EPA # 821-B-01-009 for cyanide is available from the National Technical Information Service (NTIS), PB 2001-108275, 5285 Port Royal Road, Springfield, VA 22161. The toll free telephone number is 800-553-6847. Note: A 450-W UV lamp may be used in this method instead of the 550-W lamp specified if it provides performance within the quality control (QC) acceptance criteria of the method in a given instrument. Similarly, modified flow cell configurations and flow conditions may be used in the method, provided that the QC acceptance criteria are met.


18 The description for the QuikChem Method 10-204-00-1-X, “Digestion and distillation of total cyanide in drinking and wastewaters using MICRO DIST and determination of cyanide by flow injection analysis,” Revision 2.1, November 30, 2000, for cyanide is available from Lachat Instruments, 6645 W. Mill Rd., Milwaukee, WI 53218. Telephone: 414-358-4200.


19 “Methods for the Determination of Organic and Inorganic Compounds in Drinking Water,” Vol. 1, EPA 815-R-00-014, August 2000. Available as Technical Report PB2000-106981 at National Technical Information Service (NTIS), 5301 Shawnee Road, Alexandria, VA 22312. http://www.ntis.gov.


20 Method OIA-1677, DW “Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry,” January 2004. EPA-821-R-04-001, Available from ALPKEM, A Division of OI Analytical, P.O. Box 9010, College Station, TX 77842-9010.


21 Sulfide levels below those detected using lead acetate paper may produce positive method interferences. Test samples using a more sensitive sulfide method to determine if a sulfide interference is present, and treat samples accordingly.


22 Standard Methods Online, American Public Health Association, 800 I Street NW., Washington, DC 20001, available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.


(2) Sample collection for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, nitrite, selenium, and thallium under this section shall be conducted using the sample preservation, container, and maximum holding time procedures specified in the table below:


Contaminant
Preservative
1
Container
2
Time
3
AntimonyHNO
3		P or G6 months
ArsenicConc HNO3 to pH P or G6 months
Asbestos4 °CP or G48 hours
4
BariumHNO
3		P or G6 months
BerylliumHNO
3		P or G6 months
CadmiumHNO
3		P or G6 months
ChromiumHNO
3		P or G6 months
Cyanide4 °C, NaOHP or G14 days
FluorideNoneP or G1 month
MercuryHNO
3		P or G28 days
NickelHNO
3		P or G6 months
Nitrate4 °CP or G48 hours
5
Nitrate-Nitrite
6		H
2SO
4		P or G28 days
Nitrite4 °CP or G48 hours
SeleniumHNO
3		P or G6 months
ThalliumHNO
3		P or G6 months


1 For cyanide determinations samples must be adjusted with sodium hydroxide to pH 12 at the time off collection. When chilling is indicated the sample must be shipped and stored at 4 °C or less. Acidification of nitrate or metals samples may be with a concentrated acid or a dilute (50% by volume) solution of the applicable concentrated acid. Acidification of samples for metals analysis is encouraged and allowed at the laboratory rather than at the time of sampling provided the shipping time and other instructions in Section 8.3 of EPA Methods 200.7 or 200.8 or 200.9 are followed.


2 P = plastic, hard or soft; G = glass, hard or soft.


3 In all cases samples should be analyzed as soon after collection as possible. Follow additional (if any) information on preservation, containers or holding times that is specified in method.


4 Instructions for containers, preservation procedures and holding times as specified in Method 100.2 must be adhered to for all compliance analyses including those conducted with Method 100.1.


5 If the sample is chlorinated, the holding time for an unacidified sample kept at 4 °C is extended to 14 days.


6 Nitrate-Nitrite refers to a measurement of total nitrate.


(3) Analysis under this section shall only be conducted by laboratories that have been certified by EPA or the State. Laboratories may conduct sample analysis under provisional certification until January 1, 1996. To receive certification to conduct analyses for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, nitrite and selenium and thallium, the laboratory must:


(i) Analyze Performance Evaluation (PE) samples provided by EPA, the State or by a third party (with the approval of the State or EPA) at least once a year.


(ii) For each contaminant that has been included in the PE sample and for each method for which the laboratory desires certification achieve quantitative results on the analyses that are within the following acceptance limits:


Contaminant
Acceptance limit
Antimony±30 at ≥0.006 mg/1
Arsenic±30 at ≥0.003 mg/L
Asbestos2 standard deviations based on study statistics.
Barium±15% at ≥0.15 mg/1
Beryllium±15% at ≥0.001 mg/1
Cadmium±20% at ≥0.002 mg/1
Chromium±15% at ≥0.01 mg/1
Cyanide±25% at ≥0.1 mg/1
Fluoride±10% at ≥1 to 10 mg/1
Mercury±30% at ≥0.0005 mg/1
Nickel±15% at ≥0.01 mg/1
Nitrate±10% at ≥0.4 mg/1
Nitrite±15% at ≥0.4 mg/1
Selenium±20% at ≥0.01 mg/1
Thallium±30% at ≥0.002 mg/1

(l) Analyses for the purpose of determining compliance with § 141.11 shall be conducted using the requirements specified in paragraphs (l) through (q) of this section.


(1) Analyses for all community water systems utilizing surface water sources shall be completed by June 24, 1978. These analyses shall be repeated at yearly intervals.


(2) Analyses for all community water systems utilizing only ground water sources shall be completed by June 24, 1979. These analyses shall be repeated at three-year intervals.


(3) For non-community water systems, whether supplied by surface or ground sources, analyses for nitrate shall be completed by December 24, 1980. These analyses shall be repeated at intervals determined by the State.


(4) The State has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.


(m) If the result of an analysis made under paragraph (l) of this section indicates that the level of any contaminant listed in § 141.11 exceeds the maximum contaminant level, the supplier of the water shall report to the State within 7 days and initiate three additional analyses at the same sampling point within one month.


(n) When the average of four analyses made pursuant to paragraph (m) of this section, rounded to the same number of significant figures as the maximum contaminant level for the substance in question, exceeds the maximum contaminant level, the supplier of water shall notify the State pursuant to § 141.31 and give notice to the public pursuant to subpart Q. Monitoring after public notification shall be at a frequency designated by the State and shall continue until the maximum contaminant level has not been exceeded in two successive samples or until a monitoring schedule as a condition to a variance, exemption or enforcement action shall become effective.


(o) The provisions of paragraphs (m) and (n) of this section notwithstanding, compliance with the maximum contaminant level for nitrate shall be determined on the basis of the mean of two analyses. When a level exceeding the maximum contaminant level for nitrate is found, a second analysis shall be initiated within 24 hours, and if the mean of the two analyses exceeds the maximum contaminant level, the supplier of water shall report his findings to the State pursuant to § 141.31 and shall notify the public pursuant to subpart Q.


(p) For the initial analyses required by paragraph (l) (1), (2) or (3) of this section, data for surface waters acquired within one year prior to the effective date and data for ground waters acquired within 3 years prior to the effective date of this part may be substituted at the discretion of the State.


(q) [Reserved]


[56 FR 3579, Jan. 30, 1991]


Editorial Note:For Federal Register citations affecting § 141.23, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

§ 141.24 Organic chemicals, sampling and analytical requirements.

(a)-(d) [Reserved]


(e) Analyses for the contaminants in this section shall be conducted using the methods listed in the following table, or the alternative methods listed in appendix A to subpart C of this part, or their equivalent as determined by EPA.


(1) The following documents are incorporated by reference. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be inspected at EPA’s Drinking Water Docket, 1301 Constitution Avenue, NW., EPA West, Room 3334, Washington, DC 20460 (Telephone: 202-566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Method 508A and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water, EPA/600/4-88-039, December 1988, Revised, July 1991. Methods 547, 550 and 550.1 are in Methods for the Determination of Organic Compounds in Drinking Water—Supplement I, EPA/600-4-90-020, July 1990. Methods 548.1, 549.1, 552.1 and 555 are in Methods for the Determination of Organic Compounds in Drinking Water—Supplement II, EPA/600/R-92-129, August 1992. Methods 502.2, 504.1, 505, 506, 507, 508, 508.1, 515.2, 524.2 525.2, 531.1, 551.1 and 552.2 are in Methods for the Determination of Organic Compounds in Drinking Water–Supplement III, EPA/600/R-95-131, August 1995. Method 1613 is titled “Tetra-through Octa-Chlorinated Dioxins and Furans by Isotope-Dilution HRGC/HRMS,” EPA/821-B-94-005, October 1994. These documents are available from the National Technical Information Service, NTIS PB91-231480, PB91-146027, PB92-207703, PB95-261616 and PB95-104774, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. The toll free number is: 800-553-6847. Method 6651 shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998), American Public Health Association (APHA); any of these three editions may be used. Method 6610 shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, (18th Edition Supplement) (1994), or with the 19th edition (1995) or 20th edition (1998) of Standard Methods for the Examination of Water and Wastewater; any of these publications may be used. The APHA documents are available from APHA, 1015 Fifteenth Street NW., Washington, DC 20005. Other required analytical test procedures germane to the conduct of these analyses are contained in Technical Notes on Drinking Water Methods, EPA/600/R-94-173, October 1994, NTIS PB95-104766. EPA Methods 515.3 and 549.2 are available from U.S. Environmental Protection Agency, National Exposure Research Laboratory (NERL)-Cincinnati, 26 West Martin Luther King Drive, Cincinnati, OH 45268. ASTM Method D 5317-93, 98 (Reapproved 2003) is available in the Annual Book of ASTM Standards, (1999), Vol. 11.02, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428, any edition containing the cited version of the method may be used. EPA Method 515.4, “Determination of Chlorinated Acids in Drinking Water by Liquid-Liquid Microextraction, Derivatization and Fast Gas Chromatography with Electron Capture Detection,” Revision 1.0, April 2000, EPA/815/B-00/001 and EPA Method 552.3, “Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-Liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection,” Revision 1.0, July 2003, EPA 815-B-03-002, can be accessed and downloaded directly online at http://www.epa.gov/safewater/methods/sourcalt.html. Syngenta Method AG-625, “Atrazine in Drinking Water by Immunoassay,” February 2001, is available from Syngenta Crop Protection, Inc., 410 Swing Road, P.O. Box 18300, Greensboro, NC 27419. Telephone: 336-632-6000. Method 531.2 “Measurement of N-methylcarbamoyloximes and N-methylcarbamates in Water by Direct Aqueous Injection HPLC with Postcolumn Derivatization,” Revision 1.0, September 2001, EPA 815-B-01-002, can be accessed and downloaded directly online at http://www.epa.gov/safewater/methods/sourcalt.html.


Contaminant
EPA method
Standard methods
ASTM
Other
1. Benzene502.2, 524.2
2. Carbon tetrachloride502.2, 524.2, 551.1
3. Chlorobenzene502.2, 524.2
4. 1,2-Dichlorobenzene502.2, 524.2
5. 1,4-Dichlorobenzene502.2, 524.2
6. 1,2-Dichloroethane502.2, 524.2
7. cis-Dichloroethylene502.2, 524.2
8. trans-Dichloroethylene502.2, 524.2
9. Dichloromethane502.2, 524.2
10. 1,2-Dichloropropane502.2, 524.2
11. Ethylbenzene502.2, 524.2
12. Styrene502.2, 524.2
13. Tetrachloroethylene502.2, 524.2, 551.1
14. 1,1,1-Trichloroethane502.2, 524.2, 551.1
15. Trichloroethylene502.2, 524.2, 551.1
16. Toluene502.2, 524.2
17. 1,2,4-Trichlorobenzene502.2, 524.2
18. 1,1-Dichloroethylene502.2, 524.2
19. 1,1,2-Trichloroethane502.2, 524.2, 551.1
20. Vinyl chloride502.2, 524.2
21. Xylenes (total)502.2, 524.2
22. 2,3,7,8-TCDD (dioxin)1613
23. 2,4-D
4 (as acids, salts, and esters)		515.2, 555, 515.1, 515.3, 515.4D5317-93, 98 (Reapproved 2003)
24. 2,4,5-TP
4 (Silvex)		515.2, 555, 515.1, 515.3, 515.4D5317-93, 98 (Reapproved 2003)
25. Alachlor
2		507, 525.2, 508.1, 505, 551.1
26. Atrazine
2		507, 525.2, 508.1, 505, 551.1Syngenta
5 AG-625
27. Benzo(a)pyrene525.2, 550, 550.1
28. Carbofuran531.1, 531.26610
29. Chlordane508, 525.2, 508.1, 505
30. Dalapon552.1 515.1, 552.2, 515.3, 515.4, 552.3
31. Di(2-ethylhexyl)adipate506, 525.2
32. Di(2-ethylhexyl)phthalate506, 525.2
33. Dibromochloropropane (DBCP)504.1, 551.1
34. Dinoseb
4		515.2, 555, 515.1, 515.3, 515.4
35. Diquat549.2
36. Endothall548.1
37. Endrin508, 525.2, 508.1, 505, 551.1
38. Ethylene dibromide (EDB)504.1, 551.1
39. Glyphosate5476651
40. Heptachlor508, 525.2, 508.1, 505, 551.1
41. Heptachlor Epoxide508, 525.2, 508.1, 505, 551.1
42. Hexachlorobenzene508, 525.2, 508.1, 505, 551.1
43. Hexachlorocyclopentadiene508, 525.2, 508.1, 505, 551.1
44. Lindane508, 525.2, 508.1, 505, 551.1
45. Methoxychlor508, 525.2, 508.1, 505, 551.1
46. Oxamyl531.1, 531.26610
47. PCBs
3 (as decachlorobiphenyl)		508A
48. PCBs
3 (as Aroclors)		508.1, 508, 525.2, 505
49. Pentachlorophenol515.2, 525.2, 555, 515.1, 515.3, 515.4D5317-93, 98 (Reapproved 2003)
50. Picloram
4		515.2, 555, 515.1, 515.3, 515.4D5317-93, 98 (Reapproved 2003)
51. Simazine
2		507, 525.2, 508.1, 505, 551.1
52. Toxaphene508, 508.1, 525.2, 505
53. Total Trihalomethanes502.2, 524.2, 551.1


1 [Reserved]


2 Substitution of the detector specified in Method 505, 507, 508 or 508.1 for the purpose of achieving lower detection limits is allowed as follows. Either an electron capture or nitrogen phosphorous detector may be used provided all regulatory requirements and quality control criteria are met.


3 PCBs are qualitatively identified as Aroclors and measured for compliance purposes as decachlorobiphenyl. Users of Method 505 may have more difficulty in achieving the required detection limits than users of Methods 508.1, 525.2 or 508.


4 Accurate determination of the chlorinated esters requires hydrolysis of the sample as described in EPA Methods 515.1, 515.2, 515.3, 515.4 and 555 and ASTM Method D5317-93.


5 This method may not be used for the analysis of atrazine in any system where chlorine dioxide is used for drinking water treatment. In samples from all other systems, any result for atrazine generated by Method AG-625 that is greater than one-half the maximum contaminant level (MCL) (in other words, greater than 0.0015mg/L or 1.5 μg/L) must be confirmed using another approved method for this contaminant and should use additional volume of the original sample collected for compliance monitoring. In instances where a result from Method AG-625 triggers such confirmatory testing, the confirmatory result is to be used to determine compliance.


(2) [Reserved]


(f) Beginning with the initial compliance period, analysis of the contaminants listed in § 141.61(a) (1) through (21) for the purpose of determining compliance with the maximum contaminant level shall be conducted as follows:


(1) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source, treatment plant, or within the distribution system.


(2) Surface water systems (or combined surface/ground) shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source, treatment plant, or within the distribution system.


(3) If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water representative of all sources is being used).


(4) Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in § 141.61(a) (2) through (21) during each compliance period, beginning in the initial compliance period.


(5) If the initial monitoring for contaminants listed in § 141.61(a) (1) through (8) and the monitoring for the contaminants listed in § 141.61(a) (9) through (21) as allowed in paragraph (f)(18) has been completed by December 31, 1992, and the system did not detect any contaminant listed in § 141.61(a) (1) through (21), then each ground and surface water system shall take one sample annually beginning with the initial compliance period.


(6) After a minimum of three years of annual sampling, the State may allow groundwater systems with no previous detection of any contaiminant listed in § 141.61(a) to take one sample during each compliance period.


(7) Each community and non-transient non-community ground water system which does not detect a contaminant listed in § 141.61(a) (1) through (21) may apply to the State for a waiver from the requirements of paragraphs (f)(5) and (f)(6) of this section after completing the initial monitoring. (For purposes of this section, detection is defined as ≥0.0005 mg/l.) A waiver shall be effective for no more than six years (two compliance periods). States may also issue waivers to small systems for the initial round of monitoring for 1,2,4-trichlorobenzene.


(8) A State may grant a waiver after evaluating the following factor(s):


(i) Knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If a determination by the State reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be granted.


(ii) If previous use of the contaminant is unknown or it has been used previously, then the following factors shall be used to determine whether a waiver is granted.


(A) Previous analytical results.


(B) The proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities.


(C) The environmental persistence and transport of the contaminants.


(D) The number of persons served by the public water system and the proximity of a smaller system to a larger system.


(E) How well the water source is protected against contamination, such as whether it is a surface or groundwater system. Groundwater systems must consider factors such as depth of the well, the type of soil, and wellhead protection. Surface water systems must consider watershed protection.


(9) As a condition of the waiver a groundwater system must take one sample at each sampling point during the time the waiver is effective (i.e., one sample during two compliance periods or six years) and update its vulnerability assessment considering the factors listed in paragraph (f)(8) of this section. Based on this vulnerability assessment the State must reconfirm that the system is non-vulnerable. If the State does not make this reconfirmation within three years of the initial determination, then the waiver is invalidated and the system is required to sample annually as specified in paragraph (5) of this section.


(10) Each community and non-transient non-community surface water system which does not detect a contaminant listed in § 141.61(a) (1) through (21) may apply to the State for a waiver from the requirements of (f)(5) of this section after completing the initial monitoring. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Systems meeting this criterion must be determined by the State to be non-vulnerable based on a vulnerability assessment during each compliance period. Each system receiving a waiver shall sample at the frequency specified by the State (if any).


(11) If a contaminant listed in § 141.61(a) (2) through (21) is detected at a level exceeding 0.0005 mg/l in any sample, then:


(i) The system must monitor quarterly at each sampling point which resulted in a detection.


(ii) The State may decrease the quarterly monitoring requirement speci fied in paragraph (f)(11)(i) of this section provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the State make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.


(iii) If the State determines that the system is reliably and consistently below the MCL, the State may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter(s) which previously yielded the highest analytical result.


(iv) Systems which have three consecutive annual samples with no detection of a contaminant may apply to the State for a waiver as specified in paragraph (f)(7) of this section.


(v) Groundwater systems which have detected one or more of the following two-carbon organic compounds: trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, or 1,1-dichloroethylene shall monitor quarterly for vinyl chloride. A vinyl chloride sample shall be taken at each sampling point at which one or more of the two-carbon organic compounds was detected. If the results of the first analysis do not detect vinyl chloride, the State may reduce the quarterly monitoring frequency of vinyl chloride monitoring to one sample during each compliance period. Surface water systems are required to monitor for vinyl chloride as specified by the State.


(12) Systems which violate the requirements of § 141.61(a) (1) through (21), as determined by paragraph (f)(15) of this section, must monitor quarterly. After a minimum of four consecutive quarterly samples which show the system is in compliance as specified in paragraph (f)(15) of this section the system and the State determines that the system is reliably and consistently below the maximum contaminant level, the system may monitor at the frequency and times specified in paragraph (f)(11)(iii) of this section.


(13) The State may require a confirmation sample for positive or negative results. If a confirmation sample is required by the State, the result must be averaged with the first sampling result and the average is used for the compliance determination as specified by paragraph (f)(15). States have discretion to delete results of obvious sampling errors from this calculation.


(14) The State may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection.


(i) If the concentration in the composite sample is greater than or equal to 0.0005 mg/l for any contaminant listed in § 141.61(a), then a follow-up sample must be taken within 14 days at each sampling point included in the composite, and be analyzed for that contaminant.


(ii) If duplicates of the original sample taken from each sampling point used in the composite sample are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the State within 14 days after completing analysis of the composite sample, provided the holding time of the sample is not exceeded.


(iii) If the population served by the system is >3,300 persons, then compositing may only be permitted by the State at sampling points within a single system. In systems serving ≤3,300 persons, the State may permit compositing among different systems provided the 5-sample limit is maintained.


(iv) Compositing samples prior to GC analysis.


(A) Add 5 ml or equal larger amounts of each sample (up to 5 samples are allowed) to a 25 ml glass syringe. Special precautions must be made to maintain zero headspace in the syringe.


(B) The samples must be cooled at 4 °C during this step to minimize volatilization losses.


(C) Mix well and draw out a 5-ml aliquot for analysis.


(D) Follow sample introduction, purging, and desorption steps described in the method.


(E) If less than five samples are used for compositing, a proportionately small syringe may be used.


(v) Compositing samples prior to GC/MS analysis.


(A) Inject 5-ml or equal larger amounts of each aqueous sample (up to 5 samples are allowed) into a 25-ml purging device using the sample introduction technique described in the method.


(B) The total volume of the sample in the purging device must be 25 ml.


(C) Purge and desorb as described in the method.


(15) Compliance with § 141.61(a) (1) through (21) shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.


(i) For systems monitoring more than once per year, compliance with the MCL is determined by a running annual average at each sampling point.


(ii) Systems monitoring annually or less frequently whose sample result exceeds the MCL must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling.


(iii) If any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.


(iv) If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected.


(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average.


(16) [Reserved]


(17) Analysis under this section shall only be conducted by laboratories that are certified by EPA or the State according to the following conditions (laboratories may conduct sample analysis under provisional certification until January 1, 1996):


(i) To receive certification to conduct analyses for the contaminants in § 141.61(a) (2) through (21) the laboratory must:


(A) Analyze Performance Evaluation (PE) samples provided by EPA, the State, or by a third party (with the approval of the State or EPA) at least once a year by each method for which the laboratory desires certification.


(B) Achieve the quantitative acceptance limits under paragraphs (f)(17)(i)(C) and (D) of this section for at least 80 percent of the regulated organic contaminants included in the PE sample.


(C) Achieve quantitative results on the analyses performed under paragraph (f)(17)(i)(A) of this section that are within ±20% of the actual amount of the substances in the Performance Evaluation sample when the actual amount is greater than or equal to 0.010 mg/l.


(D) Achieve quantitative results on the analyses performed under paragraph (f)(17)(i)(A) of this section that are within ±40 percent of the actual amount of the substances in the Performance Evaluation sample when the actual amount is less than 0.010 mg/l.


(E) Achieve a method detection limit of 0.0005 mg/l, according to the procedures in appendix B of part 136.


(ii) To receive certification to conduct analyses for vinyl chloride, the laboratory must:


(A) Analyze Performance Evaluation (PE) samples provided by EPA, the State, or by a third party (with the approval of the State or EPA) at least once a year by each method for which the laboratory desires certification.


(B) Achieve quantitative results on the analyses performed under paragraph (f)(17)(ii)(A) of this section that are within ±40 percent of the actual amount of vinyl chloride in the Performance Evaluation sample.


(C) Achieve a method detection limit of 0.0005 mg/l, according to the procedures in appendix B of part 136.


(D) Obtain certification for the contaminants listed in § 141.61(a)(2) through (21).


(18) States may allow the use of monitoring data collected after January 1, 1988, required under section 1445 of the Act for purposes of initial monitoring compliance. If the data are generally consistent with the other requirements of this section, the State may use these data (i.e., a single sample rather than four quarterly samples) to satisfy the initial monitoring requirement of paragraph (f)(4) of this section. Systems which use grandfathered samples and did not detect any contaminant listed § 141.61(a)(2) through (21) shall begin monitoring annually in accordance with paragraph (f)(5) of this section beginning with the initial compliance period.


(19) States may increase required monitoring where necessary to detect variations within the system.


(20) Each certified laboratory must determine the method detection limit (MDL), as defined in appendix B to part 136, at which it is capable of detecting VOCs. The acceptable MDL is 0.0005 mg/l. This concentration is the detection concentration for purposes of this section.


(21) Each public water system shall monitor at the time designated by the State within each compliance period.


(22) All new systems or systems that use a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the State. The system must also comply with the initial sampling frequencies specified by the State to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.


(g) [Reserved]


(h) Analysis of the contaminants listed in § 141.61(c) for the purposes of determining compliance with the maximum contaminant level shall be conducted as follows, with the exception that no monitoring is required for aldicarb, aldicarb sulfoxide or aldicarb sulfone:


(1) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.


(2) Surface water systems shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.



Note:

For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.


(3) If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water representative of all sources is being used).


(4) Monitoring frequency: (i) Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in § 141.61(c) during each compliance period beginning with the initial compliance period.


(ii) Systems serving more than 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of two quarterly samples in one year during each repeat compliance period.


(iii) Systems serving less than or equal to 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of one sample during each repeat compliance period.


(5) Each community and non-transient water system may apply to the State for a waiver from the requirement of paragraph (h)(4) of this section. A system must reapply for a waiver for each compliance period.


(6) A State may grant a waiver after evaluating the following factor(s): Knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If a determination by the State reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be granted. If previous use of the contaminant is unknown or it has been used previously, then the following factors shall be used to determine whether a waiver is granted.


(i) Previous analytical results.


(ii) The proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities. Non-point sources include the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.


(iii) The environmental persistence and transport of the pesticide or PCBs.


(iv) How well the water source is protected against contamination due to such factors as depth of the well and the type of soil and the integrity of the well casing.


(v) Elevated nitrate levels at the water supply source.


(vi) Use of PCBs in equipment used in the production, storage, or distribution of water (i.e., PCBs used in pumps, transformers, etc.).


(7) If an organic contaminant listed in § 141.61(c) is detected (as defined by paragraph (h)(18) of this section) in any sample, then:


(i) Each system must monitor quarterly at each sampling point which resulted in a detection.


(ii) The State may decrease the quarterly monitoring requirement specified in paragraph (h)(7)(i) of this section provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the State make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.


(iii) After the State determines the system is reliably and consistently below the maximum contaminant level the State may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter that previously yielded the highest analytical result.


(iv) Systems which have 3 consecutive annual samples with no detection of a contaminant may apply to the State for a waiver as specified in paragraph (h)(6) of this section.


(v) If the monitoring results in detection of one or more of certain related contaminants (heptachlor and heptachlor epoxide), then subsequent monitoring shall analyze for all related contaminants.


(8) Systems which violate the requirements of § 141.61(c) as determined by paragraph (h)(11) of this section must monitor quarterly. After a minimum of four quarterly samples show the system is in compliance and the State determines the system is reliably and consistently below the MCL, as specified in paragraph (h)(11) of this section, the system shall monitor at the frequency specified in paragraph (h)(7)(iii) of this section.


(9) The State may require a confirmation sample for positive or negative results. If a confirmation sample is required by the State, the result must be averaged with the first sampling result and the average used for the compliance determination as specified by paragraph (h)(11) of this section. States have discretion to delete results of obvious sampling errors from this calculation.


(10) The State may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection.


(i) If the concentration in the composite sample detects one or more contaminants listed in § 141.61(c), then a follow-up sample must be taken within 14 days at each sampling point included in the composite, and be analyzed for that contaminant.


(ii) If duplicates of the original sample taken from each sampling point used in the composite sample are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the State within 14 days after completion of the composite analysis or before the holding time for the initial sample is exceeded whichever is sooner.


(iii) If the population served by the system is >3,300 persons, then compositing may only be permitted by the State at sampling points within a single system. In systems serving ≤3,300 persons, the State may permit compositing among different systems provided the 5-sample limit is maintained.


(11) Compliance with § 141.61(c) shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.


(i) For systems monitoring more than once per year, compliance with the MCL is determined by a running annual average at each sampling point.


(ii) Systems monitoring annually or less frequently whose sample result exceeds the regulatory detection level as defined by paragraph (h)(18) of this section must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling.


(iii) If any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.


(iv) If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected.


(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average.


(12) [Reserved]


(13) Analysis for PCBs shall be conducted as follows using the methods in paragraph (e) of this section:


(i) Each system which monitors for PCBs shall analyze each sample using either Method 508.1, 525.2, 508 or 505. Users of Method 505 may have more difficulty in achieving the required Aroclor detection limits than users of Methods 508.1, 525.2 or 508.


(ii) If PCBs (as one of seven Aroclors) are detected (as designated in this paragraph) in any sample analyzed using Method 505 or 508, the system shall reanalyze the sample using Method 508A to quantitate PCBs (as decachlorobiphenyl).


Aroclor
Detection limit (mg/l)
10160.00008
12210.02
12320.0005
12420.0003
12480.0001
12540.0001
12600.0002

(iii) Compliance with the PCB MCL shall be determined based upon the quantitative results of analyses using Method 508A.


(14) If monitoring data collected after January 1, 1990, are generally consistent with the requirements of § 141.24(h), then the State may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.


(15) The State may increase the required monitoring frequency, where necessary, to detect variations within the system (e.g., fluctuations in concentration due to seasonal use, changes in water source).


(16) The State has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.


(17) Each public water system shall monitor at the time designated by the State within each compliance period.


(18) Detection as used in this paragraph shall be defined as greater than or equal to the following concentrations for each contaminant.


Contaminant
Detection limit (mg/l)
Alachlor.0002
Aldicarb.0005
Aldicarb sulfoxide.0005
Aldicarb sulfone.0008
Atrazine.0001
Benzo[a]pyrene.00002
Carbofuran.0009
Chlordane.0002
Dalapon.001
1,2-Dibromo-3-chloropropane (DBCP).00002
Di (2-ethylhexyl) adipate.0006
Di (2-ethylhexyl) phthalate.0006
Dinoseb.0002
Diquat.0004
2,4-D.0001
Endothall.009
Endrin.00001
Ethylene dibromide (EDB).00001
Glyphosate.006
Heptachlor.00004
Heptachlor epoxide.00002
Hexachlorobenzene.0001
Hexachlorocyclopentadiene.0001
Lindane.00002
Methoxychlor.0001
Oxamyl.002
Picloram.0001
Polychlorinated biphenyls (PCBs) (as decachlorobiphenyl).0001
Pentachlorophenol.00004
Simazine.00007
Toxaphene.001
2,3,7,8-TCDD (Dioxin).000000005
2,4,5-TP (Silvex).0002

(19) Anaylsis under this section shall only be conducted by laboratories that have received certification by EPA or the State and have met the following conditions:


(i) To receive certification to conduct analyses for the contaminants in § 141.61(c) the laboratory must:


(A) Analyze Performance Evaluation (PE) samples provided by EPA, the State, or by a third party (with the approval of the State or EPA) at least once a year by each method for which the laboratory desires certification.


(B) For each contaminant that has been included in the PE sample achieve quantitative results on the analyses that are within the following acceptance limits:


Contaminant
Acceptance limits (percent)
DBCP±40
EDB±40.
Alachlor±45.
Atrazine±45.
Benzo[a]pyrene2 standard deviations.
Carbofuran±45.
Chlordane±45.
Dalapon2 standard deviations.
Di(2-ethylhexyl)adipate2 standard deviations.
Di(2-ethylhexyl)phthalate2 standard deviations.
Dinoseb2 standard deviations.
Diquat2 standard deviations.
Endothall2 standard deviations.
Endrin±30.
Glyphosate2 standard deviations.
Heptachlor±45.
Heptachlor epoxide±45.
Hexachlorobenzene2 standard deviations.
Hexachloro- cyclopentadiene2 standard deviations.
Lindane±45.
Methoxychlor±45.
Oxamyl2 standard deviations.
PCBs (as Decachlorobiphenyl)0-200.
Picloram2 standard deviations.
Simazine2 standard deviations.
Toxaphene±45.
Aldicarb2 standard deviations.
Aldicarb sulfoxide2 standard deviations.
Aldicarb sulfone2 standard deviations.
Pentachlorophenol±50.
2,3,7,8-TCDD (Dioxin)2 standard deviations.
2,4-D±50.
2,4,5-TP (Silvex)±50.

(ii) [Reserved]


(20) All new systems or systems that use a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the State. The system must also comply with the initial sampling frequencies specified by the State to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.


(Approved by the Office of Management and Budget under control number 2040-0090)

[40 FR 59570, Dec. 24, 1975]


Editorial Note:For Federal Register citations affecting § 141.24, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov.

§ 141.25 Analytical methods for radioactivity.

(a) Analysis for the following contaminants shall be conducted to determine compliance with § 141.66 (radioactivity) in accordance with the methods in the following table, or the alternative methods listed in appendix A to subpart C this part, or their equivalent determined by EPA in accordance with § 141.27.


Contaminant
Methodology
Reference (Method of Page Number)
EPA
1
EPA
2
EPA
3
EPA
4
SM
5
ASTM
6
USGS
7
DOE
8
Other
Naturally Occurring:
Gross alpha
11 and beta		Evaporation900.0p. 100-01p. 1302, 7110 B, 7110 B-00R-1120-76
Gross alpha
11		Coprecipitation00-027110 C, 7110 C-00
Radium 226Radon emanation903.1p. 16Ra-04p. 19305, 7500-Ra C, 7500-Ra C-01D3454-97R-1141-76Ra-04NY
9,
Radiochemical903.0p. 13Ra-03304, 7500-Ra B, 7500-Ra B-01D2460-97R-1140-76GA
14
Radium 228Radiochemical904.0p. 24Ra-05p. 197500-Ra D, 7500-Ra D-01R-1142-76NY
9,

NJ
10,

GA
14
Uranium
12		Radiochemical908.07500-U B, 7500-U B-00
Fluorometric908.17500-U C (17th Ed.)D2907-97R-1180-76, R-1181-76U-04
ICP-MS200.8
13		3125D5673-03
Alpha Spectrometry00-07p. 337500-U C (18th, 19th, or 20th Ed.), 7500-U C-00D3972-97, 02R-1182-76U-02
Laser PhosphorimetryD5174-97, 02
Man-Made:
Radioactive CesiumRadiochemical901.0p. 47500-Cs B, 7500-Cs B-00D2459-72R-1111-76
Gamma Ray Spectrometry901.1p. 927120, 7120-97D3649-91, 98aR-1110-764.5.2.3
Radioactive IodineRadiochemical902.0p. 67500-I B, 7500-I B-00
p. 97500-I C, 7500-I C-00
7500-I D, 7500-I D-00D3649-91, 98a
Gamma Ray Spectrometry901.1p. 927120, 7120-97D4785-93, 00a4.5.2.3
Radioactive Strontium 89, 90Radiochemical905.0p. 29Sr-04p. 65303, 7500-Sr B, 7500-Sr B-01R-1160-76Sr-01, Sr-02
TritiumLiquid Scintillation906.0p. 34H-02p. 87306, 7500-
3 H B, 7500-
3 H B-00		D4107-91, 98 (Reapproved 2002)R-1171-76
Gamma EmittersGamma Ray Spectrometry901.1p. 927120, 7120-97D3649-91, 98aR-1110-76Ga-01-R
902.07500-Cs B, 7500-Cs B-00D4785-93, 00a
901.07500-I B, 7500-I B-00

The procedures shall be done in accordance with the documents listed below. The incorporation by reference of documents 1 through 10 and 13 through 14 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800-426-4791. Documents may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW., Room 3334 , Washington, DC 20460 (Telephone: 202-566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.


1 “Prescribed Procedures for the Measurement of Radioactivity in Drinking Water,” EPA 600/4-80-032, August 1980. Available at the U.S. Department of Commerce, National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161 (Telephone 800-553-6847), PB 80-224744.


2 “Interim Radiochemical Methodology for Drinking Water,” EPA 600/4-75-008 (revised), March 1976. Available NTIS, ibid.


3 “Radiochemistry Procedures Manual,” EPA 520/5-84-006, December 1987. Available NTIS, ibid.


4 “Radiochemical Analytical Procedures for Analysis of Environmental Samples,” March 1979. Available at NTIS, ibid. EMSL LV 053917.


5 “Standard Methods for the Examination of Water and Wastewater,” 13th, 17th, 18th, 19th or 20th edition, 1971, 1989, 1992, 1995, 1998. Available at American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. Methods 302, 303, 304, 305 and 306 are only in the 13th edition. Methods 7110B, 7500-Ra B, 7500-Ra C, 7500-Ra D, 7500-U B, 7500-Cs B, 7500-I B, 7500-I C, 7500-I D, 7500-Sr B, and 7500-
3H B are in the 17th, 18th, 19th and 20th editions. Method 7110 C is in the 18th, 19th and 20th editions. Method 7500-U C Fluorometric Uranium is only in the 17th Edition, and 7500-U C Alpha spectrometry is only in the 18th, 19th and 20th editions. Method 7120 is only in the 19th and 20th editions. Method 3125 is only in the 20th edition. Methods 7110 B-00, 7110 C-00, 7500-Ra B-01, 7500-Ra C-01, 7500-Ra D-01, 7500-U B-00, 7500-U C-00, 7500-I B-00, 7500-I C-00, 7500-I D-00, 7120-97, 7500-Sr B-01, and 7500-
3H B-00 are available online at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.


6 Annual Book of ASTM Standards, Vol. 11.01 and 11.02, 2002; ASTM International; any year containing the cited version of the method may be used. Copies of these two volumes and the 2003 version of D 5673-03 may be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.


7 “Methods for Determination of Radioactive Substances in Water and Fluvial Sediments,” Chapter A5 in Book 5 of Techniques of Water-Resources Investigations of the United States Geological Survey, 1977. Available at U.S. Geological Survey (USGS) Information Services, Box 25286, Federal Center, Denver, CO 80225-0425.


8 “EML Procedures Manual,” 28th (1997) or 27th (1990) Editions, Volumes 1 and 2; either edition may be used. In the 27th Edition Method Ra-04 is listed as Ra-05 and Method Ga-01-R is listed as Sect. 4.5.2.3. Available at the Environmental Measurements Laboratory, U.S. Department of Energy (DOE), 376 Hudson Street, New York, NY 10014-3621.


9 “Determination of Ra-226 and Ra-228 (Ra-02),” January 1980, Revised June 1982. Available at Radiological Sciences Institute for Laboratories and Research, New York State Department of Health, Empire State Plaza, Albany, NY 12201.


10 “Determination of Radium 228 in Drinking Water,” August 1980. Available at State of New Jersey, Department of Environmental Protection, Division of Environmental Quality, Bureau of Radiation and Inorganic Analytical Services, 9 Ewing Street, Trenton, NJ 08625.


11 Natural uranium and thorium-230 are approved as gross alpha calibration standards for gross alpha with co-precipitation and evaporation methods; americium-241 is approved with co-precipitation methods.


12 If uranium (U) is determined by mass, a 0.67 pCi/μg of uranium conversion factor must be used. This conversion factor is based on the 1:1 activity ratio of U-234 and U-238 that is characteristic of naturally occurring uranium.


13 “Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma-Mass Spectrometry,” Revision 5.4, which is published in “Methods for the Determination of Metals in Environmental Samples—Supplement I,” ‘ EPA 600-R-94-111, May 1994. Available at NTIS, PB 95-125472.


14 “The Determination of Radium-226 and Radium-228 in Drinking Water by Gamma-ray Spectrometry Using HPGE or Ge(Li) Detectors,” Revision 1.2, December 2004. Available from the Environmental Resources Center, Georgia Institute of Technology, 620 Cherry Street, Atlanta, GA 30332-0335, USA, Telephone: 404-894-3776. This method may be used to analyze for radium-226 and radium-228 in samples collected after January 1, 2005 to satisfy the radium-226 and radium-228 monitoring requirements specified at 40 CFR 141.26.


(b) When the identification and measurement of radionuclides other than those listed in paragraph (a) of this section is required, the following references are to be used, except in cases where alternative methods have been approved in accordance with § 141.27.


(1) Procedures for Radiochemical Analysis of Nuclear Reactor Aqueous Solutions, H. L. Krieger and S. Gold, EPA-R4-73-014. USEPA, Cincinnati, Ohio, May 1973.


(2) HASL Procedure Manual, Edited by John H. Harley. HASL 300, ERDA Health and Safety Laboratory, New York, NY., 1973.


(c) For the purpose of monitoring radioactivity concentrations in drinking water, the required sensitivity of the radioanalysis is defined in terms of a detection limit. The detection limit shall be that concentration which can be counted with a precision of plus or minus 100 percent at the 95 percent confidence level (1.96σ where σ is the standard deviation of the net counting rate of the sample).


(1) To determine compliance with § 141.66(b), (c), and (e) the detection limit shall not exceed the concentrations in Table B to this paragraph.


Table B—Detection Limits for Gross Alpha Particle Activity, Radium 226, Radium 228, and Uranium

Contaminant
Detection

limit
Gross alpha particle activity3 pCi/L.
Radium 2261 pCi/L.
Radium 2281 pCi/L.
Uranium1 µg/L

(2) To determine compliance with § 141.66(d) the detection limits shall not exceed the concentrations listed in Table C to this paragraph.


Table C—Detection Limits for Man-made Beta Particle and Photon Emitters

Radionuclide
Detection limit
Tritium1,000 pCi/1.
Strontium-8910 pCi/1.
Strontium-902 pCi/1.
Iodine-1311 pCi/1.
Cesium-13410 pCi/1.
Gross beta4 pCi/1.
Other radionuclides
1/10 of the applicable limit.

(d) To judge compliance with the maximum contaminant levels listed in § 141.66, averages of data shall be used and shall be rounded to the same number of significant figures as the maximum contaminant level for the substance in question.


(e) The State has the authority to determine compliance or initiate enforcement action based upon analytical results or other information compiled by their sanctioned representatives and agencies.


[41 FR 28404, July 9, 1976, as amended at 45 FR 57345, Aug. 27, 1980; 62 FR 10173, Mar. 5, 1997; 65 FR 76745, Dec. 7, 2000; 67 FR 65250, Oct. 23, 2002; 69 FR 38855, June 29, 2004; 69 FR 52180, Aug. 25, 2004; 72 FR 11245, Mar. 12, 2007; 74 FR 30958, June 29, 2009]


§ 141.26 Monitoring frequency and compliance requirements for radionuclides in community water systems.

(a) Monitoring and compliance requirements for gross alpha particle activity, radium-226, radium-228, and uranium. (1) Community water systems (CWSs) must conduct initial monitoring to determine compliance with § 141.66(b), (c), and (e) by December 31, 2007. For the purposes of monitoring for gross alpha particle activity, radium-226, radium-228, uranium, and beta particle and photon radioactivity in drinking water, “detection limit” is defined as in § 141.25(c).


(i) Applicability and sampling location for existing community water systems or sources. All existing CWSs using ground water, surface water or systems using both ground and surface water (for the purpose of this section hereafter referred to as systems) must sample at every entry point to the distribution system that is representative of all sources being used (hereafter called a sampling point) under normal operating conditions. The system must take each sample at the same sampling point unless conditions make another sampling point more representative of each source or the State has designated a distribution system location, in accordance with paragraph (a)(2)(ii)(C) of this section.


(ii) Applicability and sampling location for new community water systems or sources. All new CWSs or CWSs that use a new source of water must begin to conduct initial monitoring for the new source within the first quarter after initiating use of the source. CWSs must conduct more frequent monitoring when ordered by the State in the event of possible contamination or when changes in the distribution system or treatment processes occur which may increase the concentration of radioactivity in finished water.


(2) Initial monitoring: Systems must conduct initial monitoring for gross alpha particle activity, radium-226, radium-228, and uranium as follows:


(i) Systems without acceptable historical data, as defined below, must collect four consecutive quarterly samples at all sampling points before December 31, 2007.


(ii) Grandfathering of data: States may allow historical monitoring data collected at a sampling point to satisfy the initial monitoring requirements for that sampling point, for the following situations.


(A) To satisfy initial monitoring requirements, a community water system having only one entry point to the distribution system may use the monitoring data from the last compliance monitoring period that began between June 2000 and December 8, 2003.


(B) To satisfy initial monitoring requirements, a community water system with multiple entry points and having appropriate historical monitoring data for each entry point to the distribution system may use the monitoring data from the last compliance monitoring period that began between June 2000 and December 8, 2003.


(C) To satisfy initial monitoring requirements, a community water system with appropriate historical data for a representative point in the distribution system may use the monitoring data from the last compliance monitoring period that began between June 2000 and December 8, 2003, provided that the State finds that the historical data satisfactorily demonstrate that each entry point to the distribution system is expected to be in compliance based upon the historical data and reasonable assumptions about the variability of contaminant levels between entry points. The State must make a written finding indicating how the data conforms to the these requirements.


(iii) For gross alpha particle activity, uranium, radium-226, and radium-228 monitoring, the State may waive the final two quarters of initial monitoring for a sampling point if the results of the samples from the previous two quarters are below the detection limit.


(iv) If the average of the initial monitoring results for a sampling point is above the MCL, the system must collect and analyze quarterly samples at that sampling point until the system has results from four consecutive quarters that are at or below the MCL, unless the system enters into another schedule as part of a formal compliance agreement with the State.


(3) Reduced monitoring: States may allow community water systems to reduce the future frequency of monitoring from once every three years to once every six or nine years at each sampling point, based on the following criteria.


(i) If the average of the initial monitoring results for each contaminant (i.e., gross alpha particle activity, uranium, radium-226, or radium-228) is below the detection limit specified in Table B, in § 141.25(c)(1), the system must collect and analyze for that contaminant using at least one sample at that sampling point every nine years.


(ii) For gross alpha particle activity and uranium, if the average of the initial monitoring results for each contaminant is at or above the detection limit but at or below
1/2 the MCL, the system must collect and analyze for that contaminant using at least one sample at that sampling point every six years. For combined radium-226 and radium-228, the analytical results must be combined. If the average of the combined initial monitoring results for radium-226 and radium-228 is at or above the detection limit but at or below
1/2 the MCL, the system must collect and analyze for that contaminant using at least one sample at that sampling point every six years.


(iii) For gross alpha particle activity and uranium, if the average of the initial monitoring results for each contaminant is above
1/2 the MCL but at or below the MCL, the system must collect and analyze at least one sample at that sampling point every three years. For combined radium-226 and radium-228, the analytical results must be combined. If the average of the combined initial monitoring results for radium-226 and radium-228 is above
1/2 the MCL but at or below the MCL, the system must collect and analyze at least one sample at that sampling point every three years.


(iv) Systems must use the samples collected during the reduced monitoring period to determine the monitoring frequency for subsequent monitoring periods (e.g., if a system’s sampling point is on a nine year monitoring period, and the sample result is above
1/2 MCL, then the next monitoring period for that sampling point is three years).


(v) If a system has a monitoring result that exceeds the MCL while on reduced monitoring, the system must collect and analyze quarterly samples at that sampling point until the system has results from four consecutive quarters that are below the MCL, unless the system enters into another schedule as part of a formal compliance agreement with the State.


(4) Compositing: To fulfill quarterly monitoring requirements for gross alpha particle activity, radium-226, radium-228, or uranium, a system may composite up to four consecutive quarterly samples from a single entry point if analysis is done within a year of the first sample. States will treat analytical results from the composited as the average analytical result to determine compliance with the MCLs and the future monitoring frequency. If the analytical result from the composited sample is greater than
1/2 MCL, the State may direct the system to take additional quarterly samples before allowing the system to sample under a reduced monitoring schedule.


(5) A gross alpha particle activity measurement may be substituted for the required radium-226 measurement provided that the measured gross alpha particle activity does not exceed 5 pCi/l. A gross alpha particle activity measurement may be substituted for the required uranium measurement provided that the measured gross alpha particle activity does not exceed 15 pCi/l. The gross alpha measurement shall have a confidence interval of 95% (1.65σ, where σ is the standard deviation of the net counting rate of the sample) for radium-226 and uranium. When a system uses a gross alpha particle activity measurement in lieu of a radium-226 and/or uranium measurement, the gross alpha particle activity analytical result will be used to determine the future monitoring frequency for radium-226 and/or uranium. If the gross alpha particle activity result is less than detection,
1/2 the detection limit will be used to determine compliance and the future monitoring frequency.


(b) Monitoring and compliance requirements for beta particle and photon radioactivity. To determine compliance with the maximum contaminant levels in § 141.66(d) for beta particle and photon radioactivity, a system must monitor at a frequency as follows:


(1) Community water systems (both surface and ground water) designated by the State as vulnerable must sample for beta particle and photon radioactivity. Systems must collect quarterly samples for beta emitters and annual samples for tritium and strontium-90 at each entry point to the distribution system (hereafter called a sampling point), beginning within one quarter after being notified by the State. Systems already designated by the State must continue to sample until the State reviews and either reaffirms or removes the designation.


(i) If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity at a sampling point has a running annual average (computed quarterly) less than or equal to 50 pCi/L (screening level), the State may reduce the frequency of monitoring at that sampling point to once every 3 years. Systems must collect all samples required in paragraph (b)(1) of this section during the reduced monitoring period.


(ii) For systems in the vicinity of a nuclear facility, the State may allow the CWS to utilize environmental surveillance data collected by the nuclear facility in lieu of monitoring at the system’s entry point(s), where the State determines if such data is applicable to a particular water system. In the event that there is a release from a nuclear facility, systems which are using surveillance data must begin monitoring at the community water system’s entry point(s) in accordance with paragraph (b)(1) of this section.


(2) Community water systems (both surface and ground water) designated by the State as utilizing waters contaminated by effluents from nuclear facilities must sample for beta particle and photon radioactivity. Systems must collect quarterly samples for beta emitters and iodine-131 and annual samples for tritium and strontium-90 at each entry point to the distribution system (hereafter called a sampling point), beginning within one quarter after being notified by the State. Systems already designated by the State as systems using waters contaminated by effluents from nuclear facilities must continue to sample until the State reviews and either reaffirms or removes the designation.


(i) Quarterly monitoring for gross beta particle activity shall be based on the analysis of monthly samples or the analysis of a composite of three monthly samples. The former is recommended.


(ii) For iodine-131, a composite of five consecutive daily samples shall be analyzed once each quarter. As ordered by the State, more frequent monitoring shall be conducted when iodine-131 is identified in the finished water.


(iii) Annual monitoring for strontium-90 and tritium shall be conducted by means of the analysis of a composite of four consecutive quarterly samples or analysis of four quarterly samples. The latter procedure is recommended.


(iv) If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity at a sampling point has a running annual average (computed quarterly) less than or equal to 15 pCi/L (screening level), the State may reduce the frequency of monitoring at that sampling point to every 3 years. Systems must collect the same type of samples required in paragraph (b)(2) of this section during the reduced monitoring period.


(v) For systems in the vicinity of a nuclear facility, the State may allow the CWS to utilize environmental surveillance data collected by the nuclear facility in lieu of monitoring at the system’s entry point(s), where the State determines if such data is applicable to a particular water system. In the event that there is a release from a nuclear facility, systems which are using surveillance data must begin monitoring at the community water system’s entry point(s) in accordance with paragraph (b)(2) of this section.


(3) Community water systems designated by the State to monitor for beta particle and photon radioactivity can not apply to the State for a waiver from the monitoring frequencies specified in paragraph (b)(1) or (b)(2) of this section.


(4) Community water systems may analyze for naturally occurring potassium-40 beta particle activity from the same or equivalent sample used for the gross beta particle activity analysis. Systems are allowed to subtract the potassium-40 beta particle activity value from the total gross beta particle activity value to determine if the screening level is exceeded. The potassium-40 beta particle activity must be calculated by multiplying elemental potassium concentrations (in mg/L) by a factor of 0.82.


(5) If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity exceeds the appropriate screening level, an analysis of the sample must be performed to identify the major radioactive constituents present in the sample and the appropriate doses must be calculated and summed to determine compliance with § 141.66(d)(1), using the formula in § 141.66(d)(2). Doses must also be calculated and combined for measured levels of tritium and strontium to determine compliance.


(6) Systems must monitor monthly at the sampling point(s) which exceed the maximum contaminant level in § 141.66(d) beginning the month after the exceedance occurs. Systems must continue monthly monitoring until the system has established, by a rolling average of 3 monthly samples, that the MCL is being met. Systems who establish that the MCL is being met must return to quarterly monitoring until they meet the requirements set forth in paragraph (b)(1)(i) or (b)(2)(iv) of this section.


(c) General monitoring and compliance requirements for radionuclides. (1) The State may require more frequent monitoring than specified in paragraphs (a) and (b) of this section, or may require confirmation samples at its discretion. The results of the initial and confirmation samples will be averaged for use in compliance determinations.


(2) Each public water systems shall monitor at the time designated by the State during each compliance period.


(3) Compliance: Compliance with § 141.66 (b) through (e) will be determined based on the analytical result(s) obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.


(i) For systems monitoring more than once per year, compliance with the MCL is determined by a running annual average at each sampling point. If the average of any sampling point is greater than the MCL, then the system is out of compliance with the MCL.


(ii) For systems monitoring more than once per year, if any sample result will cause the running average to exceed the MCL at any sample point, the system is out of compliance with the MCL immediately.


(iii) Systems must include all samples taken and analyzed under the provisions of this section in determining compliance, even if that number is greater than the minimum required.


(iv) If a system does not collect all required samples when compliance is based on a running annual average of quarterly samples, compliance will be based on the running average of the samples collected.


(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average, unless a gross alpha particle activity is being used in lieu of radium-226 and/or uranium. If the gross alpha particle activity result is less than detection,
1/2 the detection limit will be used to calculate the annual average.


(4) States have the discretion to delete results of obvious sampling or analytic errors.


(5) If the MCL for radioactivity set forth in § 141.66 (b) through (e) is exceeded, the operator of a community water system must give notice to the State pursuant to § 141.31 and to the public as required by subpart Q of this part.


[65 FR 76745, Dec. 7, 2000, as amended at 69 FR 38855, June 29, 2004]


§ 141.27 Alternate analytical techniques.

(a) With the written permission of the State, concurred in by the Administrator of the U.S. EPA, an alternate analytical technique may be employed. An alternate technique shall be accepted only if it is substantially equivalent to the prescribed test in both precision and accuracy as it relates to the determination of compliance with any MCL. The use of the alternate analytical technique shall not decrease the frequency of monitoring required by this part.


[45 FR 57345, Aug. 27, 1980]


§ 141.28 Certified laboratories.

(a) For the purpose of determining compliance with § 141.21 through 141.27, 141.30, 141.40, 141.74, 141.89 and 141.402, samples may be considered only if they have been analyzed by a laboratory certified by the State except that measurements of alkalinity, disinfectant residual, orthophosphate, pH, silica, temperature, and turbidity may be performed by any person acceptable to the State.


(b) Nothing in this part shall be construed to preclude the State or any duly designated representative of the State from taking samples or from using the results from such samples to determine compliance by a supplier of water with the applicable requirements of this part.


[45 FR 57345, Aug. 27, 1980; 47 FR 10999, Mar. 12, 1982, as amended at 59 FR 34323, July 1, 1994; 64 FR 67465, Dec. 1, 1999; 71 FR 65651, Nov. 8, 2006; 86 FR 4282, Jan. 15, 2021]


§ 141.29 Monitoring of consecutive public water systems.

When a public water system supplies water to one or more other public water systems, the State may modify the monitoring requirements imposed by this part to the extent that the interconnection of the systems justifies treating them as a single system for monitoring purposes. Any modified monitoring shall be conducted pursuant to a schedule specified by the State and concurred in by the Administrator of the U.S. Environmental Protection Agency.


Appendix A to Subpart C of Part 141—Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

Only the editions stated in the following table are approved.


Alternative Testing Methods for Contaminants Listed at 40 CFR 141.21(f)(3)

Organism
Methodology
SM 21st Edition
1
SM 22nd Edition
28
SM Online
3
Other
Total ColiformsTotal Coliform Fermentation Technique9221 A, B9221 A, B9221 A,B-06
Total Coliform Membrane Filter Technique9222 A, B, C
Presence-Absence (P-A) Coliform Test9221 D
ONPG-MUG Test92239223 B9223 B-04
Colitag
TM		Modified Colitag
TM
13
Tecta EC/TC
33

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.21(f)(5)

Organism
Methodology
SM 22nd Edition
28
SM Online
3
Fecal ColiformsFecal Coliform Procedure9221 E9221 E-06

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.21(f)(6)

Organism
Methodology
SM 20th

Edition
6
SM 21st

Edition
1
SM 22nd

Edition
28
SM Online
3
Other
E.coliONPG-MUG Test9223 B9223 B9223 B9223 B-97, B-04
Colitag
TM		Modified Colitag
TM
13
Tecta EC/TC
33

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.23(k)(1)

Contaminant
Methodology
EPA method
SM 21st

edition
1
SM 22nd

edition
28
SM 23rd

edition,
49 SM

24th edition
66
SM online
3
ASTM
4
Other
AlkalinityTitrimetric2320 B2320 B2320 BD1067-06 B, 11 B, 16 B
AntimonyHydride—Atomic AbsorptionD 3697-07, -12, -17
Atomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
ArsenicAtomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10D 2972-08 C, -15 C
Hydride Atomic Absorption3114 B3114 B3114 B3114 B-09D 2972-08 B, -15 B
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
BariumInductively Coupled Plasma3120 B3120 B3120 B
Atomic Absorption; Direct3111 D3111 D3111 D
Atomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
BerylliumInductively Coupled Plasma3120 B3120 B3120 B
Atomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10D 3645-08 B, -15 B
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
CadmiumAtomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
CalciumEDTA titrimetric3500-Ca B3500-Ca B3500-Ca BD 511-09, -14 A
Atomic Absorption; Direct Aspiration3111 B3111 B3111 BD 511-09, -14 B
Inductively Coupled Plasma3120 B3120 B3120 B
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Ion ChromatographyD 6919-09, -17
ChromiumInductively Coupled Plasma3120 B3120 B3120 B
Atomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
CopperAtomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10D 1688-07, -12 C, 17 C
Atomic Absorption; Direct Aspiration3111 B3111 B3111 BD 1688-07, -12 A, 17 A
Inductively Coupled Plasma3120 B3120 B3120 B
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
ColorimetryHach Method 8026,
35 Hach Method 10272.
36
ConductivityConductance2510 B2510 B2510 BD 1125-14 A
CyanideManual Distillation with MgCl2 followed by:4500-CN−C4500-CN−C4500-CN−C4500-CN−C-99D 2036-06 A
Spectrophotometric, Amenable4500-CN−G4500-CN−G4500-CN−GD 2036-06 B
Spectrophotometric Manual4500-CN−E4500-CN−E4500-CN−ED2036-06 A
Selective Electrode4500-CN−F4500-CN−F4500-CN−F
Gas Chromatography/Mass Spectrometry HeadspaceME355.01.
7
FluorideIon Chromatography4110 B4110 B4110 BD 4327-11, -17
Manual Distillation; Colorimetric SPADNS4500-F−B, D4500-F−B, D4500-F−B, D
Manual Electrode4500-F−C4500-F−C4500-F−CD 1179-04, 10 B, 16 B
Automated Alizarin4500-F−E4500-F−E4500-F−E
Arsenite-Free Colorimetric SPADNSHach SPADNS 2 Method 10225,
22 Hach Method 10312.
67
LeadAtomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10D 3559-08 D, 15 D
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Differential Pulse Anodic Stripping VoltametryMethod 1001, Rev. 1.1.
57
MagnesiumAtomic Absorption3111 B3111 B3111 BD 511-09, -14 B
Inductively Coupled Plasma3120 B3120 B3120 B
Complexation Titrimetric Methods3500-Mg B3500-Mg B3500-Mg BD 511-09, -14 A
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Ion ChromatographyD 6919-09, -17
MercuryManual, Cold Vapor3112 B3112 B3112 B3112 B-09D 3223-12, -17
NickelInductively Coupled Plasma3120 B3120 B3120 B
Atomic Absorption; Direct3111 B3111 B3111 B
Atomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
NitrateIon Chromatography4110 B4110 B4110 BD 4327-11, -17
Automated Cadmium Reduction4500-NO3−F4500-NO3−F4500-NO3−F
Manual Cadmium Reduction4500-NO3− E4500-NO3− E4500-NO3− E
Ion Selective Electrode4500-NO3− D4500-NO3− D4500-NO3− D
Reduction/ColorimetricSystea Easy (1-Reagent),
8 NECi Nitrate-Reductase.
40
Colorimetric; DirectHach TNTplus
TM 835/836 Method 10206.
23
Capillary Ion ElectrophoresisD 6508-15
NitriteIon Chromatography4110 B4110 B4110 BD 4327-11, -17
Automated Cadmium Reduction4500-NO3−F4500-NO3−F4500-NO3−F
Manual Cadmium Reduction4500-NO3−E4500-NO3−E4500-NO3−E
Spectrophotometric4500-NO2−B4500-NO2−B4500-NO2−B
Reduction/ColorimetricSystea Easy (1-Reagent),
8 NECi Nitrate-Reductase.
40
Capillary Ion ElectrophoresisD 6508-15
Ortho-phosphateIon Chromatography4110 B4110 B4110 BD 4327-11, -17
Colorimetric, ascorbic acid, single reagent4500-P E4500-P E4500-P E4500-P E-99
Colorimetric, Automated, Ascorbic Acid4500-P F4500-P F4500-P F4500-P F-99Thermo Fisher Discrete Analyzer.
41
Capillary Ion ElectrophoresisD 6508-15
pHElectrometric
48 150.3		4500-H
+ B		4500-H
+ B		4500-H
+ B		D 1293-12, -18
SeleniumHydride-Atomic Absorption3114 B3114 B3114 B3114 B-09D 3859-08 A, -15 A
Atomic Absorption; Furnace3113 B3113 B3113 B3113 B-04, B-10D 3859-08 B, -15 B
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
SilicaColorimetricD859-05, 10, 16
Molybdosilicate4500-SiO2 C4500-SiO2 C4500-SiO2 C
Heteropoly blue4500-SiO2 D4500-SiO2 D4500-SiO2 D
Automated for Molybdate-reactive Silica4500-SiO2 E4500-SiO2 E4500-SiO2 E
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Inductively Coupled Plasma3120 B3120 B3120 B
SodiumAtomic Absorption; Direct Aspiration3111 B3111 B3111 B
Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Ion ChromatographyD 6919-09, -17
TemperatureThermometric2550255025502550-10

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.24(e)(1)

Contaminant
Methodology
EPA method
SM 21st edition
1
SM 22nd

edition,
28 SM

23rd edition,
49 SM

24th edition
66
SM online
3
ASTM
4
Other
BenzenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
Carbon tetrachloridePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
ChlorobenzenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,2-DichlorobenzenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,4-DichlorobenzenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,2-DichloroethanePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
cis-DichloroethylenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
trans-DichloroethylenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
DichloromethanePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,2-DichloropropanePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
EthylbenzenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
StyrenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4
29
TetrachloroethylenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,1,1-TrichloroethanePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
TrichloroethylenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
ToluenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,2,4-TrichlorobenzenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
1,1-DichloroethylenePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4
29
1,1,2-TrichlorethanePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
Vinyl chloridePurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
Xylenes (total)Purge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29
2,4-DGas Chromatography/Electron Capture Detection (GC/ECD)6640 B6640 B6640 B-01, B-06D 5317-20
2,4,5-TP (Silvex)Gas Chromatography/Electron Capture Detection (GC/ECD)6640 B6640 B6640 B-01, B-06D 5317-20
AlachlorSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
AtrazineLiquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS)536.
25
Solid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3,
24 523.
26
Benzo(a)pyreneSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
CarbofuranHigh-performance liquid chromatography (HPLC) with post-column derivatization and fluorescence detection6610 B6610 B6610 B-04
Liquid Chromatography/Mass SpectrometryME 531.
58
ChlordaneSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
DalaponIon Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS)557.
14
Gas Chromatography/Electron Capture Detection (GC/ECD)6640 B6640 B6640 B-01, B-06
Di(2-ethylhexyl)adipateSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
Di(2-ethylhexyl)phthalateSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
Dibromochloropropane (DBCP)Purge &Trap/Gas Chromatography/Mass Spectrometry524.3.
9
DinosebGas Chromatography/Electron Capture Detection (GC/ECD)6640 B6640 B6640 B-01, B-06
EndrinSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
Ethyl dibromide (EDB)Purge &Trap/Gas Chromatography/Mass Spectrometry524.3.
9
GlyphosateHigh-Performance Liquid Chromatography (HPLC) with Post-Column Derivatization and Fluorescence Detection6651 B6651 B6651 B-00, B-05
HeptachlorSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
Heptachlor EpoxideSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
HexachlorobenzeneSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
Hexachlorocyclo-pentadieneSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
LindaneSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
MethoxychlorSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
OxamylHigh-performance liquid chromatography (HPLC) with post-column derivatization and fluorescence detection6610 B6610 B6610 B-04
Liquid Chromatography/Mass SpectrometryME 531.
58
PCBs (as Aroclors)Solid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
PentachlorophenolGas Chromatography/Electron Capture Detection (GC/ECD)6640 B6640 B6640 B-01, B-06D 5317-20
Solid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
PicloramGas Chromatography/Electron Capture Detection (GC/ECD)6640 B6640 B6640 B-01, B-06D 5317-20
SimazineLiquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS)536.
25
Solid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3,
24 523.
26
ToxapheneSolid Phase Extraction/Gas Chromatography/Mass Spectrometry (GC/MS)525.3.
24
Total TrihalomethanesPurge &Trap/Gas Chromatography/Mass Spectrometry524.3,
9 524.4.
29

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.25(a)

Contaminant
Methodology
EPA method
SM 21st edition
1
SM 22nd edition,
28 SM 23rd edition,
49 SM 24th edition
66
ASTM
4
SM online
3
Naturally Occurring:
Gross alpha and betaEvaporation900.0, Rev. 1.0
50		7110 B7110 B
Liquid Scintillation7110 DD 7283-177110 D-17.
Gross alphaCoprecipitation7110 C7110 C
Radium 226Radon emanation903.1, Rev. 1.0
53		7500-Ra C7500-Ra CD 3454-05, -18, D 3454-21
Radiochemical903.0, Rev. 1.0
54		7500-Ra B7500-Ra BD 2460-07
Gamma Spectrometry7500-Ra E7500-Ra E-07.
Radium 228Radiochemical904.0, Rev. 1.0
62		7500-Ra D7500-Ra D
Gamma Spectrometry7500-Ra E7500-Ra E-07.
UraniumRadiochemical7500-U B7500-U B
ICP-MS3125D 5673-05, 10, 16
Alpha spectrometry7500-U C7500-U CD 3972-09
Laser PhosphorimetryD 5174-07
Alpha Liquid Scintillation SpectrometryD 6239-09
Man-Made:
Radioactive CesiumRadiochemical7500-Cs B7500-Cs B
Gamma Ray Spectrometry71207120D 3649-06
Radioactive IodineRadiochemical7500-I B, 7500-I C, 7500-I D7500-I B, 7500-I C, 7500-I DD 3649-06
Gamma Ray Spectrometry71207120D 4785-08, -20
Radioactive Strontium 89, 90Radiochemical7500-Sr B7500-Sr B
TritiumLiquid Scintillation7500-
3H B		7500-
3H B		D 4107-08, -20
Gamma EmittersGamma Ray Spectrometry7120, 7500-Cs B, 7500-I B7120, 7500-Cs B, 7500-I BD 3649-06, D 4785-08, -20

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.74(a)(1)

Organism
Methodology
SM 21st edition
1
SM 22nd

edition
28
SM 23rd edition
49
SM 24th edition
66
SM online
3
Other
Total ColiformTotal Coliform Fermentation Technique9221 A, B, C9221 A, B, C9221 A, B, C9221 A, B, C9221 A, B, C-06
Total Coliform Membrane Filter Technique9222 A, B, C9222 A, B, C9222 A, B, C
ONPG-MUG Test92239223 B9223 B9223 B9223 B-04
Fecal ColiformsFecal Coliform Procedure9221 E9221 E9221 E9221 E9221 E-06
Fecal Coliform Filter Procedure9222 D9222 D9222 D9222 D9222 D-06
Heterotrophic bacteriaPour Plate Method9215 B9215 B9215 B9215 B-04
TurbidityNephelometric Method2130 B2130 B2130 B2130 BHach Method 8195, Rev. 3.0.
52
Laser Nephelometry (on-line)Mitchell M5271,
10 Mitchell M5331, Rev. 1.2,
42 Lovibond PTV 6000.
46
LED Nephelometry (on-line)Mitchell M5331,
11 Mitchell M5331, Rev. 1.2,
42 Lovibond PTV 2000,
45 Yokogawa 820.
68
LED Nephelometry (on-line)AMI Turbiwell,
15 Lovibond PTV 1000.
44
LED Nephelometry (portable)Orion AQ4500,
12 Lovibond TB 3500,
64 Lovibond TB 5000.
65
Laser Nephelometry (portable)Lovibond TB 6000.
63
360° NephelometryHach Method 10258, Rev. 1.0,
39 Hach Method 10258, Rev. 2.0.
51

Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.74(a)(2)

Residual
Methodology
EPA methods
SM 21st edition
1
SM 22nd edition,
28 SM 23rd edition,
49 SM 24th edition
66
ASTM
4
Other
Free ChlorineAmperometric Titration4500-Cl D4500-Cl DD 1253-08, -14
DPD Ferrous Titrimetric4500-Cl F4500-Cl F
DPD Colorimetric4500-Cl G4500-Cl GHach Method 10260.
31
Indophenol ColorimetricHach Method 10241.
34
Syringaldazine (FACTS)4500-Cl H4500-Cl H
On-line Chlorine AnalyzerEPA 334.0.
16
Amperometric SensorChloroSense,
17 ChloroSense, Rev. 1.1.
59
Total ChlorineAmperometric Titration4500-Cl D4500-Cl DD 1253-08, -14
Amperometric Titration (Low level measurement)4500-Cl E4500-Cl E
DPD Ferrous Titrimetric4500-Cl F4500-Cl F
DPD Colorimetric4500-Cl G4500-Cl GHach Method 10260.
31
Indophenol Colorimetric127.
55
Iodometric Electrode4500-Cl I4500-Cl I
On-line Chlorine AnalyzerEPA 334.0.
16
Amperometric SensorChloroSense,
17 ChloroSense, Rev. 1.1.
59
Chlorine DioxideAmperometric Titration4500-ClO2 C4500-ClO2 C
Amperometric Titration4500-ClO2 E4500-ClO2 E
Amperometric SensorChlordioX Plus,
32 ChlordioX Plus, Rev. 1.1.
60
OzoneIndigo Method4500-O3 B4500-O3 B

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.131(b)(1)

Contaminant
Methodology
EPA method
ASTM
4
SM online
3
SM 21st edition
1
SM 22nd

edition,
28 SM

23rd edition,
49

SM 24th

Edition
66
Other
TTHMP&T/GC/MS524.3,
9 524.4.
29
HAA5LLE (diazomethane)/GC/ECD6251 B-076251 B6251 B
Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS)557.
14
Two-Dimensional Ion Chromatography (IC) with Suppressed Conductivity DetectionThermo Fisher 557.1.
47
BromateTwo-Dimensional Ion Chromatography (IC)302.0
18
Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS)557.
14
Chemically Suppressed Ion ChromatographyD 6581-08 A
Electrolytically Suppressed Ion ChromatographyD 6581-08 B
ChloriteChemically Suppressed Ion ChromatographyD 6581-08 A
Electrolytically Suppressed Ion ChromatographyD 6581-08 B
Chlorite—daily monitoring as prescribed in 40 CFR 141.132(b)(2)(i)(A)Amperometric Titration4500-ClO2 E4500-ClO2 E
Amperometric SensorChlordioX Plus,
32 ChlordioX Plus, Rev. 1.1.
60

Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.131(c)(1)

Residual
Methodology
SM 21
st edition
1
SM 22
nd edition,
28 SM 23
rd edition,
49 SM 24
th edition
66
ASTM
4
Other
Free ChlorineAmperometric Titration4500-Cl D4500-Cl DD 1253-08, -14
DPD Ferrous Titrimetric4500-Cl F4500-Cl F
DPD Colorimetric4500-Cl G4500-Cl GHach Method 10260.
31
Indophenol ColorimetricHach Method 10241.
34
Syringaldazine (FACTS)4500-Cl H4500-Cl H
Amperometric SensorChloroSense,
17 ChloroSense, Rev. 1.1.
59
On-line Chlorine AnalyzerEPA 334.0.
16
Combined ChlorineAmperometric Titration4500-Cl D4500-Cl DD 1253-08, -14.
DPD Ferrous Titrimetric4500-Cl F4500-Cl F
DPD Colorimetric4500-Cl G4500-Cl GHach Method 10260.
31
Total ChlorineAmperometric Titration4500-Cl D4500-Cl DD 1253-08, -14
>Low level Amperometric Titration4500-Cl E4500-Cl E
DPD Ferrous Titrimetric4500-Cl F4500-Cl F
DPD Colorimetric4500-Cl G4500-Cl GHach Method 10260.
31
Iodometric Electrode4500-Cl I4500-Cl I
Amperometric SensorChloroSense,
17 ChloroSense, Rev. 1.1.
59
On-line Chlorine AnalyzerEPA 334.0.
16
Chlorine DioxideAmperometric Method II4500-ClO2 E4500-ClO2 E
Amperometric SensorChlordioX Plus,
32 ChlordioX Plus, Rev. 1.1.
60

Alternative Testing Methods for Parameters Listed at 40 CFR 141.131(d)

Parameter
Methodology
SM 21
st edition
1
SM 22
nd edition
28
SM 23
rd edition
49, SM 24
th edition
66
SM online
3
EPA
Other
Total Organic Carbon (TOC)High Temperature Combustion5310 B5310 B5310 B415.3, Rev 1.2
19
Persulfate-Ultraviolet or Heated Persulfate Oxidation5310 C5310 C5310 C415.3, Rev 1.2
19		Hach Method 10267
38.
Wet Oxidation5310 D5310 D415.3, Rev 1.2
19
Ozone OxidationHach Method 10261
37.
Specific Ultraviolet Absorbance (SUVA)Calculation using DOC and UV254 data415.3, Rev 1.2
19
Dissolved Organic Carbon (DOC)High Temperature Combustion5310 B5310 B5310 B415.3, Rev 1.2
19
Persulfate-Ultraviolet or Heated Persulfate Oxidation5310 C5310 C5310 C415.3, Rev 1.2
19
Wet Oxidation5310 D5310 D415.3, Rev 1.2
19
Ultraviolet absorption at 254 nm (UV254)Spectrophotometry5910 B5910 B5910 B5910 B-11415.3, Rev 1.2
19

Alternative Testing Methods With MRL ≤0.0010 mg/L for Monitoring Listed at 40 CFR 141.132(b)(3)(ii)(B)

Contaminant
Methodology
EPA method
BromateTwo-Dimensional Ion Chromatography (IC)302.0
18
Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS)557
14

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.402(c)(2)

Organism
Methodology
SM 20
th edition
6
SM 21
st edition
1
SM 22
nd edition
28
SM 23
rd edition
49, SM 24
th edition
66
SM online
3
Other
E. coliColilert9223 B9223 B9223 B9223 B-97, B-04
Colisure9223 B9223 B9223 B9223 B-97, B-04
Colilert-189223 B9223 B9223 B9223 B9223 B-97, B-04
Readycult®Readycult®.
20
ColitagModified ColitagTM
13, Modified Colitag TM, Version 2.0.
61
Chromocult®Chromocult®.
21
EC-MUG9221 F9221 F9221 F-06
NA-MUG9222 I
mColiBlue24 Test9222 J
Tecta EC/TC
33
43
RAPID’E.coli 2
56
EnterococciMultiple-Tube Technique9230 B9230 B-04
Membrane Filter Techniques9230 C
Fluorogenic Substrate Enterococcus Test (using Enterolert)9230 D
ColiphageTwo-Step Enrichment Presence-Absence ProcedureFast Phage.
30

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.704(b)

Organism
Methodology
SM 20th edition
6
E. coliMembrane Filtration, Two Step9222 D/9222 G

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.852(a)(5)

Organism
Methodology category
Method
SM 20
th, 21
st editions
1
6
SM 22
nd edition
28
SM 23
rd edition
49, SM 24
th edition
66
SM online
3
Total ColiformsLactose Fermentation MethodsStandard Total Coliform Fermentation Technique9221 B.1, B.29221 B.1, B.2, B.3, B.49221 B.1, B.2-06.
Presence-Absence (P-A) Coliform Test9221 D.1, D.2, D.3
Membrane Filtration MethodsStandard Total Coliform Membrane Filter Procedure using Endo Media9222 B, C
Simultaneous Detection of Total Coliforms and E. coli by Dual Chromogen Membrane Filter Procedure (using mColiBlue24 medium)9222 J
Simultaneous Detection of Total Coliform Bacteria and Escherichia coli Using RAPID’E.coli (REC2) in Drinking Water
56
Enzyme Substrate MethodsColilert®9223 B9223 B9223 B-04.
Colisure®9223 B9223 B9223 B-04.
Colilert-189223 B9223 B9223 B9223 B-04.
Tecta EC/TC
33
43
Modified ColitagTM, Version 2.0
61
Escherichia coliEscherichia coli Procedure (following Lactose Fermentation Methods)EC-MUG medium9221 F.19221 F.19221 F.1-06.
Escherichia coli Partitioning Methods (following Membrane Filtration Methods)EC broth with MUG (EC-MUG)9222 H
NA-MUG medium9222 I
Simultaneous Detection of Total Coliforms and E. coli by Dual Chromogen Membrane Filter ProceduremColiBlue24 medium9222 J
Membrane Filtration MethodSimultaneous Detection of Total Coliform Bacteria and Escherichia coli Using RAPID’E.coli (REC2) in Drinking Water
56
Enzyme Substrate MethodsColilert®9223 B9223 B9223 B-04.
Colisure®9223 B9223 B9223 B-04.
Colilert-189223 B9223 B9223 B9223 B-04.
Tecta EC/TC
33
43
Modified ColitagTM, Version 2.0
61

Alternative Testing Methods for Contaminants Listed at 40 CFR 143.4(b)

Contaminant
Methodology
EPA method
ASTM
4
SM 21
st edition
1
SM 22
nd edition,
28 SM 23
rd edition,
49 SM 24
th edition
66
SM online
3
AluminumAxially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Atomic Absorption; Direct3111 D3111 D
Atomic Absorption; Furnace3113 B3113 B3113 B-04, B-10.
Inductively Coupled Plasma3120 B3120 B

ChlorideSilver Nitrate TitrationD 512-04 B, 12 B4500-Cl
−B		4500-Cl
−B
Ion ChromatographyD 4327-11, -174110 B4110 B
Potentiometric Titration4500-Cl
−D		4500-Cl
−D
ColorVisual Comparison2120 B2120 B
Foaming AgentsMethylene Blue Active Substances (MBAS)5540 C5540 C
IronAxially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Atomic Absorption; Direct3111 B3111 B
Atomic Absorption; Furnace3113 B3113 B3113 B-04, B-10
Inductively Coupled Plasma3120 B3120 B
ManganeseAxially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Atomic Absorption; Direct3111 B3111 B
Atomic Absorption; Furnace3113 B3113 B3113 B-04, B-10.
Inductively Coupled Plasma3120 B3120 B
OdorThreshold Odor Test2150 B2150 B
SilverAxially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Atomic Absorption; Direct3111 B3111 B
Atomic Absorption; Furnace3113 B3113 B3113 B-04, B-10.
Inductively Coupled Plasma3120 B3120 B
SulfateIon ChromatographyD 4327-11, -174110 B4110 B
Gravimetric with ignition of residue4500-SO4
2
−C		4500-SO4
2
−C		4500-SO4
2
−C-97.
Gravimetric with drying of residue4500-SO4
2
−D		4500-SO4
2
−D		4500-SO4
2
−D-97.
Turbidimetric methodD 516-07, 11, 164500-SO4
2
−E		4500-SO4
2
−E		4500-SO4
2
−E-97.
Automated methylthymol blue method4500-SO4
2
−F		4500-SO4
2
−F		4500-SO4
2
−F-97.
Total Dissolved SolidsTotal Dissolved Solids Dried at 180 deg C2540 C2540 C
ZincAxially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)200.5, Revision 4.2
2
Atomic Absorption; Direct Aspiration3111 B3111 B
Inductively Coupled Plasma3120 B3120 B


1 Standard Methods for the Examination of Water and Wastewater, 21st edition (2005). Available from American Public Health Association, 800 I Street NW, Washington, DC 20001-3710.


2 EPA Method 200.5, Revision 4.2. “Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry.” 2003. EPA/600/R-06/115. (Available at http://www.epa.gov/water-research/epa-drinking-water-research-methods.)


3 Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.


4 Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 or http://astm.org. The methods listed are the only alternative versions that may be used.


5 Method D99-003, Revision 3.0. “Free Chlorine Species (HOCl− and OCl−) by Test Strip,” November 21, 2003. Available from Industrial Test Systems, Inc., 1875 Langston St., Rock Hill, SC 29730.


6 Standard Methods for the Examination of Water and Wastewater, 20th edition (1998). Available from American Public Health Association, 800 I Street NW, Washington, DC 20001-3710.


7 Method ME355.01, Revision 1.0. “Determination of Cyanide in Drinking Water by GC/MS Headspace,” May 26, 2009. Available at https://www.nemi.gov or from James Eaton, H & E Testing Laboratory, 221 State Street, Augusta, ME 04333. (207) 287-2727.


8 Systea Easy (1-Reagent). “Systea Easy (1-Reagent) Nitrate Method,” February 4, 2009. Available at https://www.nemi.gov or from Systea Scientific, LLC., 900 Jorie Blvd., Suite 35, Oak Brook, IL 60523.


9 EPA Method 524.3, Version 1.0. “Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry,” June 2009. EPA 815-B-09-009. Available at https://www.nemi.gov.


10 Mitchell Method M5271, Revision 1.1. “Determination of Turbidity by Laser Nephelometry,” March 5, 2009. Available at https://www.nemi.gov or from Leck Mitchell, Ph.D., PE, 656 Independence Valley Dr., Grand Junction, CO 81507.


11 Mitchell Method M5331, Revision 1.1. “Determination of Turbidity by LED Nephelometry,” March 5, 2009. Available at https://www.nemi.gov or from Leck Mitchell, Ph.D., PE, 656 Independence Valley Dr., Grand Junction, CO 81507.


12 Orion Method AQ4500, Revision 1.0. “Determination of Turbidity by LED Nephelometry,” May 8, 2009. Available at https://www.nemi.gov or from Thermo Scientific, 166 Cummings Center, Beverly, MA 01915, http://www.thermo.com.


13 Modified ColitagTM Method. “Modified ColitagTM Test Method for the Simultaneous Detection of E. coli and other Total Coliforms in Water (ATP D05-0035),” August 28, 2009. Available at https://www.nemi.gov or from CPI International, 5580 Skylane Boulevard, Santa Rosa, CA 95403.


14 EPA Method 557. “Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS),” September 2009. EPA 815-B-09-012. Available at https://www.nemi.gov.


15 AMI Turbiwell, “Continuous Measurement of Turbidity Using a SWAN AMI Turbiwell Turbidimeter,” August 2009. Available at https://www.nemi.gov or from Markus Bernasconi, SWAN Analytische Instrumente AG, Studbachstrasse 13, CH-8340 Hinwil, Switzerland.


16 EPA Method 334.0. “Determination of Residual Chlorine in Drinking Water Using an On-line Chlorine Analyzer,” September 2009. EPA 815-B-09-013. Available at https://www.nemi.gov.


17 ChloroSense. “Measurement of Free and Total Chlorine in Drinking Water by Palintest ChloroSense,” August 2009. Available at https://www.nemi.gov or from Palintest Ltd, 1455 Jamike Avenue (Suite 100), Erlanger, KY 41018.


18 EPA Method 302.0. “Determination of Bromate in Drinking Water using Two-Dimensional Ion Chromatography with Suppressed Conductivity Detection,” September 2009. EPA 815-B-09-014. Available at https://www.nemi.gov.


19 EPA 415.3, Revision 1.2. “Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water,” September 2009. EPA/600/R-09/122. Available at http://www.epa.gov/water-research/epa-drinking-water-research-methods.


20 Readycult® Method, “Readycult® Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” January, 2007. Version 1.1. Available from EMD Millipore (division of Merck KGaA, Darmstadt, Germany), 290 Concord Road, Billerica, MA 01821.


21 Chromocult® Method, “Chromocult® Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” November, 2000. Version 1.0. EMD Millipore (division of Merck KGaA, Darmstadt, Germany), 290 Concord Road, Billerica, MA 01821.


22 Hach Company. “Hach Company SPADNS 2 (Arsenite-Free) Fluoride Method 10225-Spectrophotometric Measurement of Fluoride in Water and Wastewater,” January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, Colorado 80539.


23 Hach Company. “Hach Company TNTplus
TM 835/836 Nitrate Method 10206-Spectrophotometric Measurement of Nitrate in Water and Wastewater,” January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, Colorado 80539.


24 EPA Method 525.3. “Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS),” February 2012. EPA/600/R-12/010. Available at http://www.epa.gov/water-research/epa-drinking-water-research-methods.


25 EPA Method 536. “Determination of Triazine Pesticides and their Degradates in Drinking Water by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS),” October 2007. EPA 815-B-07-002. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


26 EPA Method 523. “Determination of Triazine Pesticides and their Degradates in Drinking Water by Gas Chromatography/Mass Spectrometry (GC/MS),” February 2011. EPA 815-R-11-002. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


27 EPA Method 1623.1. “Cryptosporidium and Giardia in Water by Filtration/IMS/FA,” 2012. EPA-816-R-12-001. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


28 Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012). Available from American Public Health Association, 800 I Street NW, Washington, DC 20001-3710.


29 EPA Method 524.4, Version 1.0. “Measurement of Purgeable Organic Compounds in Water by Gas Chromatography/Mass Spectrometry using Nitrogen Purge Gas.” May 2013. EPA 815-R-13-002. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


30 Charm Sciences Inc. “Fast Phage Test Procedure. Presence/Absence for Coliphage in Ground Water with Same Day Positive Prediction”. Version 009. November 2012. 659 Andover Street, Lawrence, MA 01843. Available at www.charmsciences.com.


31 Hach Company. “Hach Method 10260-Determination of Chlorinated Oxidants (Free and Total) in Water Using Disposable Planar Reagent-filled Cuvettes and Mesofluidic Channel Colorimetry,” April 2013. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


32 ChlordioX Plus. “Chlorine Dioxide and Chlorite in Drinking Water by Amperometry using Disposable Sensors,” November 2013.

Available from Palintest Ltd, 1455 Jamike Avenue (Suite 100), Erlanger, KY 41018.


33 Tecta EC/TC. “TechtaTM EC/TC Medium and TechtaTM Instrument: A Presence/Absence Method for the Simultaneous Detection of Total Coliforms and Escherichia coli (E. coli) in Drinking Water,” version 1.0, May 2014. Available from Pathogen Detection Systems, Inc., 382 King Street East, Kingston, Ontario, Canada, K7K 2Y2.


34 Hach Company. “Hach Method 10241-Spectrophotometric Measurement of Free Chlorine (Cl2) in Drinking Water,” November 2015. Revision 1.2. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


35 Hach Company. “Hach Method 8026-Spectrophotometric Measurement of Copper in Finished Drinking Water,” December 2015. Revision 1.2. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


36 Hach Company. “Hach Method 10272-Spectrophotometric Measurement of Copper in Finished Drinking Water,” December 2015. Revision 1.2. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


37 Hach Company. “Hach Method 10261-Total Organic Carbon in Finished Drinking Water by Catalyzed Ozone Hydroxyl Radical Oxidation Infrared Analysis,” December 2015. Revision 1.2. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


38 Hach Company. “Hach Method 10267-Spectrophotometric Measurement of Total Organic Carbon (TOC) in Finished Drinking Water,” December 2015. Revision 1.2. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


39 Hach Company. “Hach Method 10258-Determination of Turbidity by 360° Nephelometry,” January 2016. Revision 1.0. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


40 Nitrate Elimination Company Inc. (NECi). “Method for Nitrate Reductase Nitrate-Nitrogen Analysis of Drinking Water,” February 2016. Superior Enzymes Inc., 334 Hecla Street, Lake Linden, Michigan 49945.


41 Thermo Fisher. “Thermo Fisher Scientific Drinking Water Orthophosphate Method for Thermo Scientific Gallery Discrete Analyzer,” February 2016. Revision 5. Thermo Fisher Scientific, Ratastie 2, 01620 Vantaa, Finland.


42 Mitchell Method M5331, Revision 1.2. “Determination of Turbidity by LED or Laser Nephelometry,” February 2016. Available from Leck Mitchell, Ph.D., PE, 656 Independence Valley Dr., Grand Junction, CO 81507.


43 Tecta EC/TC. “TectaTM EC/TC Medium and the TectaTM Instrument: A Presence/Absence Method for the Simultaneous Detection of Total Coliforms and Escherichia coli (E. coli) in Drinking Water,” version 2.0, March 2017. Available from Pathogen Detection Systems, Inc., 382 King Street East, Kingston, Ontario, Canada, K7K 2Y2.


44 Lovibond PTV 1000. “Continuous Measurement of Drinking Water Turbidity using a Lovibond PTV 1000 White Light LED Turbidimeter,” December 2016. Revision 1.0. Available from Tintometer, Inc., 6456 Parkland Drive, Sarasota, FL 34243.


45 Lovibond PTV 2000. “Continuous Measurement of Drinking Water Turbidity Using a Lovibond PTV 2000 660-nm LED Turbidimeter,” December 2016. Revision 1.0. Available from Tintometer, Inc., 6456 Parkland Drive, Sarasota, FL 34243.


46 Lovibond PTV 6000. “Continuous Measurement of Drinking Water Turbidity Using a Lovibond PTV 6000 Laser Turbidimeter,” December 2016. Revision 1.0. Available from Tintometer, Inc., 6456 Parkland Drive, Sarasota, FL 34243.


47 Thermo Fisher. “Thermo Fisher method 557.1: Determination of Haloacetic Acids in Drinking Water using Two-Dimensional Ion Chromatography with Suppressed Conductivity Detection,” January 2017. Version 1.0. Available from Thermo Fisher Scientific, 490 Lakeside Dr., Sunnyvale, CA 94085 ([email protected]).


48 EPA Method 150.3. “Determination of pH in Drinking Water,” February 2017. EPA 815-B-17-001. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


49 Standard Methods for the Examination of Water and Wastewater, 23rd edition (2017). Available from American Public Health Association, 800 I Street NW, Washington, DC 20001-3710.


50 EPA Method 900.0, Rev. 1.0. “Determination of Gross Alpha and Gross Beta in Drinking Water,” February 2018. EPA 815-B-18-002. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


51 Hach Company. “Hach Method 10258—Determination of Turbidity by 360° Nephelometry.” March 2018. Revision 2.0. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


52 Hach Company. “Hach Method 8195-Determination of Turbidity by Nephelometry.” March 2018. Revision 3.0. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.


53 EPA Method 903.1, Rev. 1.0. “Radium-226 in Drinking Water Radon Emanation Technique.” January 2021. EPA 815-B-21-003. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


54 EPA Method 903.0, Rev. 1.0. “Alpha-Emitting Radium Isotopes in Drinking Water.” January 2021. EPA 815-B-21-002. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


55 EPA Method 127. “Determination of Monochloramine Concentration in Drinking Water.” January 2021. EPA 815-B-21-004. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


56 Bio-Rad. “Simultaneous Detection of Total Coliform Bacteria and Escherichia coli using RAPID’E. coli 2 (REC2) in Drinking Water.” May 2020. Bio-Rad Laboratories, 2000 Nobel Drive, Hercules, California 94547.


57 Method 1001, Rev. 1.1. “Lead in Drinking Water by Differential Pulse Anodic Stripping Voltammetry.” May 2020. Palintest Ltd, 400 Corporate Circle, Suite J, Golden, CO 80401.


58 ME 531, Version 1.0. “Measurement of N-Methylcarbamoyloximes and N-Methylcarbamates in Drinking Water by LC-MS/MS. September 2019. Maine Health Environmental Testing Laboratory, 221 State Street, Augusta, ME 04330.


59 ChloroSense, Rev. 1.1. “Free and Total Chlorine in Drinking Water by Amperometry using Disposable Sensors.” February 2020. Palintest Ltd, 400 Corporate Circle, Suite J, Golden, CO 80401.


60 ChlordioX Plus, Rev. 1.1. “Chlorine Dioxide and Chlorite in Drinking Water by Amperometry using Disposable Sensors.” February 2020. Palintest Ltd, 400 Corporate Circle, Suite J, Golden, CO 80401.


61 Modified ColitagTM, Version 2.0. “Modified ColitagTM Test Method for the Simultaneous Determination of Total Coliforms and E. coli in Water.” June 2020. Neogen Corporation, 620 Lesher Place, Lansing, MI 48912.


62 EPA Method 904.0, Rev. 1.0. “Radium-228 in Drinking Water.” March 2022. EPA 815-B-22-003. Available at the National Service Center for Environmental Publications at https://www.epa.gov/nscep.


63 Lovibond TB 6000. “Measurement of Drinking Water Turbidity of a Captured Sample using a Lovibond Portable Laser Turbidimeter.” May 2021. Revision 1.0. Available from Tintometer, Inc., 6456 Parkland Drive, Sarasota, FL 34243.


64 Lovibond TB 3500. “Measurement of Drinking Water Turbidity of a Captured Sample using a Lovibond White Light LED Portable Turbidimeter.” May 2021. Revision 1.0. Available from Tintometer, Inc., 6456 Parkland Drive, Sarasota, FL 34243.


65 Lovibond TB 5000. “Measurement of Drinking Water Turbidity of a Captured Sample using a Lovibond 660-nm LED Portable Turbidimeter.” May 2021. Revision 1.0. Available from Tintometer, Inc., 6456 Parkland Drive, Sarasota, FL 34243.


66 Standard Methods for the Examination of Water and Wastewater, 24th edition (2023). Available from American Public Health Association, 800 I Street NW, Washington, DC 20001-3710.


67 Hach Company. “Hach Method 10312—Spectrophotometric Measurement of Fluoride in Finished Drinking Water Aluminum-Chromeazurol S complex (AL-CAS) Using Planar Reagent-filled Cuvettes”. August 2022. Revision 1.0. 5600 Lindbergh Drive, Loveland, Colorado 80539.


68 Yokogawa Electric Corporation. “Yokogawa Method 820—Measurement of Turbidity in Drinking Water by Right Angle Scattered Light Turbidity Analyzer”. November 2022. Revision 1.0. 2-9-32 Nakamachi, Musashino-shi, Tokyo, Japan 180-8750.


[74 FR 38353, Aug. 3, 2009, as amended at 74 FR 57914, Nov. 10, 2009; 74 FR 63069, Dec. 2, 2009; 75 FR 32299, June 8, 2010; 76 FR 37018, June 24, 2011; 77 FR 38527, June 28, 2012; 78 FR 32565, May 31, 2013; 78 FR 37463, June 21, 2013; 79 FR 35086, June 19, 2014; 79 FR 36428, June 27, 2014; 81 FR 46844, July 19, 2016; 82 FR 34867, July 27, 2017; 83 FR 51644, Oct. 12, 2018; 83 FR 54676, Oct. 31, 2018; 86 FR 28284, May 26, 2021; 86 FR 29526, June 2, 2021; 87 FR 50579, Aug. 17, 2022; 89 FR 5780, Jan. 30, 2024; 89 FR 7624, Feb. 5, 2024]


Subpart D—Reporting and Recordkeeping

§ 141.31 Reporting requirements.

(a) Except where a shorter period is specified in this part, the supplier of water shall report to the State the results of any test measurement or analysis required by this part within (1) The first ten days following the month in which the result is received, or (2) the first ten days following the end of the required monitoring period as stipulated by the State, whichever of these is shortest.


(b) Except where a different reporting period is specified in this part, the supplier of water must report to the State within 48 hours the failure to comply with any national primary drinking water regulation (including failure to comply with monitoring requirements) set forth in this part.


(c) The supplier of water is not required to report analytical results to the State in cases where a State laboratory performs the analysis and reports the results to the State office which would normally receive such notification from the supplier.


(d)(1) The public water system, within 10 days of completing the public notification requirements under subpart Q of this part for the initial public notice and any repeat notices, must submit to the primary agency a certification that it has fully complied with the public notification regulations. For Tier 2 and 3 notices, the public water system must include with this certification a representative copy of each type of notice distributed, published, posted, and made available to the persons served by the system and to the media.


(2) For Tier 1 notices for a lead action level exceedance, public water systems must provide a copy of any Tier 1 notice to the Administrator and the head of the primacy agency as soon as practicable, but not later than 24 hours after the public water system learns of the violation or exceedance.


(e) The water supply system shall submit to the State within the time stated in the request copies of any records required to be maintained under § 141.33 hereof or copies of any documents then in existence which the State or the Administrator is entitled to inspect pursuant to the authority of section 1445 of the Safe Drinking Water Act or the equivalent provisions of State law.


[40 FR 59570, Dec. 24, 1975, as amended at 45 FR 57345, Aug. 27, 1980; 65 FR 26022, May 4, 2000; 86 FR 4282, Jan. 15, 2021]


§ 141.32 [Reserved]

§ 141.33 Record maintenance.

Any owner or operator of a public water system subject to the provisions of this part shall retain on its premises or at a convenient location near its premises the following records:


(a) Records of microbiological analyses and turbidity analyses made pursuant to this part shall be kept for not less than 5 years. Records of chemical analyses made pursuant to this part shall be kept for not less than 10 years. Actual laboratory reports may be kept, or data may be transferred to tabular summaries, provided that the following information is included:


(1) The date, place, and time of sampling, and the name of the person who collected the sample;


(2) Identification of the sample as to whether it was a routine distribution system sample, check sample, raw or process water sample or other special purpose sample;


(3) Date of analysis;


(4) Laboratory and person responsible for performing analysis;


(5) The analytical technique/method used; and


(6) The results of the analysis.


(b) Records of action taken by the system to correct violations of primary drinking water regulations shall be kept for a period not less than 3 years after the last action taken with respect to the particular violation involved.


(c) Copies of any written reports, summaries or communications relating to sanitary surveys of the system conducted by the system itself, by a private consultant, or by any local, State or Federal agency, shall be kept for a period not less than 10 years after completion of the sanitary survey involved.


(d) Records concerning a variance or exemption granted to the system shall be kept for a period ending not less than 5 years following the expiration of such variance or exemption.


(e) Copies of public notices issued pursuant to subpart Q of this part and certifications made to the primacy agency pursuant to § 141.31 must be kept for three years after issuance.


(f) Copies of monitoring plans developed pursuant to this part shall be kept for the same period of time as the records of analyses taken under the plan are required to be kept under paragraph (a) of this section, except as specified elsewhere in this part.


[40 FR 59570, Dec. 24, 1975, as amended at 65 FR 26022, May 4, 2000; 71 FR 478, Jan. 4, 2006]


§ 141.34 [Reserved]

§ 141.35 Reporting for unregulated contaminant monitoring results.

(a) General applicability. This section applies to any owner or operator of a public water system (PWS) required to monitor for unregulated contaminants under § 141.40(a); such owner or operator is referred to as “you.” This section specifies the information that must be reported to EPA prior to the commencement of monitoring and describes the process for reporting monitoring results to EPA. For the purposes of this section, PWS “population served” is the retail population served directly by the PWS as reported to the Federal Safe Drinking Water Information System (SDWIS/Fed). For purposes of this section, the term “finished” means water that is introduced into the distribution system of a PWS and is intended for distribution and consumption without further treatment, except the treatment necessary to maintain water quality in the distribution system (e.g., booster disinfection, addition of corrosion control chemicals). For purposes of this section, the term “State” refers to the State or Tribal government entity that has jurisdiction over your PWS even if that government does not have primary enforcement responsibility for PWSs under the Safe Drinking Water Act. For purposes of this section, the term “PWS Official” refers to the person at your PWS who is able to function as the official spokesperson for the system’s Unregulated Contaminant Monitoring Regulation (UCMR) activities; and the term “PWS Technical Contact” refers to the person at your PWS who is responsible for the technical aspects of your UCMR activities, such as details concerning sampling and reporting.


(b) Reporting by all systems. You must meet the reporting requirements of this paragraph if you meet the applicability criteria in § 141.40(a)(1) and (2).


(1) Where to submit UCMR reporting requirement information. Some of your reporting requirements are to be fulfilled electronically and others by mail. Information that must be submitted using EPA’s electronic data reporting system must be submitted through: https://www.epa.gov/dwucmr. Documentation that is required to be mailed can be submitted either: To UCMR Sampling Coordinator, USEPA, Technical Support Center, 26 West Martin Luther King Drive (MS 140), Cincinnati, OH 45268; or by email at [email protected]. In addition, you must notify the public of the availability of unregulated contaminant monitoring data as provided in subpart Q (Public Notification) of this part (40 CFR 141.207). Community Water Systems that detect unregulated contaminants under this monitoring must also address such detections as part of their Consumer Confidence Reports, as provided in subpart O of this part (40 CFR 141.151).


(2) Contacting EPA if your system does not meet applicability criteria or has a status change. If you have received a letter from EPA or your State concerning your required monitoring and your system does not meet the applicability criteria for UCMR established in § 141.40(a)(1) or (2), or if a change occurs at your system that may affect your requirements under UCMR as defined in § 141.40(a)(3) through (5), you must mail or email a letter to EPA, as specified in paragraph (b)(1) of this section. The letter must be from your PWS Official and must include your PWS Identification (PWSID) Code along with an explanation as to why the UCMR requirements are not applicable to your PWS, or have changed for your PWS, along with the appropriate contact information. EPA will make an applicability determination based on your letter and in consultation with the State when necessary. You are subject to UCMR requirements unless and until you receive a letter from EPA agreeing that you do not meet the applicability criteria.


(c) Reporting by large systems. If you serve a population of more than 10,000 people, and meet the applicability criteria in § 141.40(a)(2)(i), you must meet the reporting requirements in paragraphs (c)(1) through (8) of this section.


(1) Contact and zip code information. You must provide contact information by December 31, 2022, and provide updates within 30 days if this information changes. The contact information must be submitted using EPA’s electronic data reporting system, as specified in paragraph (b)(1) of this section, and include the name, affiliation, mailing address, phone number, and email address for your PWS Technical Contact and your PWS Official. In addition, as a one-time reporting requirement, you must report the U.S. Postal Service Zip Code(s) for all areas being served water by your PWS.


(2) Sampling location inventory information. You must provide your inventory information by December 31, 2022, using EPA’s electronic data reporting system, as specified in paragraph (b)(1) of this section. You must submit, verify, or update data elements 1-9 (as defined in Table 1 of paragraph (e) of this section) for each sampling location, or for each approved representative sampling location (as specified in paragraph (c)(3) of this section) regarding representative sampling locations. If this information changes, you must report updates, including new sources, and sampling locations that are put in use before or during the UCMR sampling period, to EPA’s electronic data reporting system within 30 days of the change.


(3) Proposed ground water representative sampling locations. Some systems that use ground water as a source and have multiple entry points to the distribution system (EPTDSs) may propose monitoring at representative entry point(s), rather than monitor at every EPTDS, as follows:


(i) Qualifications. Large PWSs that have EPA- or State-approved representative EPTDS sampling locations from a previous UCMR cycle, or as provided for under 40 CFR 141.23(a)(1), 40 CFR 141.24(f)(1), or 40 CFR 141.24(h)(1), may submit a copy of documentation from your State or EPA that approves your representative sampling plan. PWSs that do not have an approved representative EPTDS sampling plan may submit a proposal to sample at representative EPTDS(s) rather than at each individual EPTDS if: You use ground water as a source; all of your well sources have either the same treatment or no treatment; and you have multiple EPTDSs from the same source (i.e., same aquifer). You must submit a copy of the existing or proposed representative EPTDS sampling plan, as appropriate, at least six months prior to your scheduled sample collection, as specified in paragraph (b)(1) of this section. If changes to your inventory that impact your representative plan occur before or during the UCMR sampling period, you must report updates within 30 days of the change.


(ii) Demonstration. If you are submitting a proposal to sample at representative EPTDS(s) rather than at each individual EPTDS, you must demonstrate that any EPTDS that you propose as representative of multiple wells is associated with a well that draws from the same aquifer as the wells it will represent. The proposed well must be representative of the highest annual volume and most consistently active wells in the representative array. If that representative well is not in use at the scheduled sampling time, you must select and sample an alternative representative well. You must submit the information defined in Table 1, paragraph (e) of this section for each proposed representative sampling location. You must also include documentation to support your proposal that the specified wells are representative of other wells. This documentation can include system-maintained well logs or construction drawings indicating that the representative well(s) is/are at a representative depth, and details of well casings and grouting; data demonstrating relative homogeneity of water quality constituents (e.g., pH, dissolved oxygen, conductivity, iron, manganese) in samples drawn from each well; and data showing that your wells are located in a limited geographic area (e.g., all wells within a 0.5 mile radius) and/or, if available, the hydrogeologic data indicating the ground water travel time between the representative well and each of the individual wells it represents (e.g., all wells within a five-year time of travel delineation). Your proposal must be sent in writing to EPA, as specified in paragraph (b)(1) of this section.


(iii) Approval. EPA or the State (as specified in the Partnership Agreement reached between the State and EPA) will review your proposal and coordinate any necessary changes with you. Your plan will not be final until you receive written approval from EPA, identifying the final list of EPTDSs where you will be required to monitor.


(4) Contacting EPA if your PWS has not been notified of requirements. If you believe you are subject to UCMR requirements, as defined in 40 CFR 141.40(a)(1) and (a)(2)(i), and you have not been contacted by either EPA or your State by April 26, 2022, you must send a letter to EPA, as specified in paragraph (b)(1) of this section. The letter must be from your PWS Official and must include an explanation as to why the UCMR requirements are applicable to your system along with the appropriate contact information. A copy of the letter must also be submitted to the State as directed by the State. EPA will make an applicability determination based on your letter, and in consultation with the State when necessary and will notify you regarding your applicability status and required sampling schedule. However, if your PWS meets the applicability criteria specified in 40 CFR 141.40(a)(2)(i), you are subject to the UCMR monitoring and reporting requirements, regardless of whether you have been contacted by the State or EPA.


(5) Notifying EPA if your PWS cannot sample according to schedule—


(i) General rescheduling notification requirements. Large systems may independently change their monitoring schedules up to December 31, 2022, using EPA’s electronic data reporting system, as specified in paragraph (b)(1) of this section. After this date has passed, if your PWS cannot sample according to your assigned sampling schedule (e.g., because of budget constraints, or if a sampling location will be closed during the scheduled month of monitoring), you must mail or email a letter to EPA, as specified in paragraph (b)(1) of this section, prior to the scheduled sampling date. You must include an explanation of why the samples cannot be taken according to the assigned schedule, and you must provide the alternative schedule you are requesting. You must not reschedule monitoring specifically to avoid sample collection during a suspected vulnerable period. You are subject to your assigned UCMR sampling schedule or the schedule that you revised on or before December 31, 2022, unless and until you receive a letter from EPA specifying a new schedule.


(ii) Exceptions to the rescheduling notification requirements. For ground water sampling, if the second round of sampling will be completed five to seven months after the first sampling event, as specified in Table 2 of § 141.40(a)(4)(i)(B), no notification to EPA is required. If any ground water sampling location will be non-operational for more than one month before and one month after the month in which the second sampling event is scheduled (i.e., it is not possible for you to sample within the five to seven month window), you must notify EPA, as specified in paragraph (b)(1) of this section, explaining why the schedule cannot be met. You must comply with any modified schedule provided by EPA.


(6) Reporting monitoring results. For UCMR samples, you must report all data elements specified in Table 1 of paragraph (e) of this section, using EPA’s electronic data reporting system. You also must report any changes, relative to what is currently posted, made to data elements 1 through 9 to EPA in writing, explaining the nature and purpose of the proposed change, as specified in paragraph (b)(1) of this section.


(i) Electronic reporting system. You are responsible for ensuring that the laboratory conducting the analysis of your unregulated contaminant monitoring samples (your laboratory) posts the analytical results to EPA’s electronic reporting system. You are also responsible for reviewing, approving, and submitting those results to EPA.


(ii) Reporting schedule. You must require your laboratory, on your behalf, to post and approve the data in EPA’s electronic data reporting system, accessible at https://www.epa.gov/dwucmr, for your review within 90 days from the sample collection date (sample collection must occur as specified in 40 CFR 141.40(a)(4)). You then have 30 days from when the laboratory posts and approves your data to review, approve, and submit the data to the State and EPA via the agency’s electronic data reporting system. If you do not electronically approve and submit the laboratory data to EPA within 30 days of the laboratory posting approved data, the data will be considered approved by you and available for State and EPA review.


(7) Only one set of results accepted. If you report more than one set of valid results for the same sampling location and the same sampling event (for example, because you have had more than one laboratory analyze replicate samples collected under § 141.40(a)(5), or because you have collected multiple samples during a single monitoring event at the same sampling location), EPA will use the highest of the reported values as the official result.


(8) No reporting of previously collected data. You cannot report previously collected data to meet the testing and reporting requirements for the contaminants listed in § 141.40(a)(3). All analyses must be performed by laboratories approved by EPA to perform UCMR analyses using the analytical methods specified in Table 1 of § 141.40(a)(3) and using samples collected according to § 141.40(a)(4). Such requirements preclude the possibility of “grandfathering” previously collected data.


(d) Reporting by small systems. If you serve a population of 10,000 or fewer people, and you are notified that you have been selected for UCMR monitoring, your reporting requirements will be specified within the materials that EPA sends you, including a request for contact information, and a request for information associated with the sampling kit.


(1) Contact and zip code information. EPA will send you a notice requesting contact information for key individuals at your system, including name, affiliation, mailing address, phone number and email address. These individuals include your PWS Technical Contact and your PWS Official. You are required to provide this contact information within 90 days of receiving the notice from EPA as specified in paragraph (b)(1) of this section. If this contact information changes, you also must provide updates within 30 days of the change, as specified in paragraph (b)(1) of this section. In addition, as a one-time reporting requirement, you must report the U.S. Postal Service Zip Code(s) for all areas being served water by your PWS.


(2) Sampling location inventory information. You must provide your inventory information by December 31, 2022, using EPA’s electronic data reporting system, as specified in paragraph (b)(1) of this section. If this information changes, you must report updates, including new sources, and sampling locations that are put in use before or during the UCMR sampling period, to EPA’s electronic data reporting system within 30 days of the change, as specified in paragraph (b)(1) of this section. You must record all data elements listed in Table 1 of paragraph (e) of this section on each sample form and sample bottle, as appropriate, provided to you by the UCMR Sampling Coordinator. You must send this information as specified in the instructions of your sampling kit, which will include the due date and return address. You must report any changes made in data elements 1 through 9 by emailing an explanation of the nature and purpose of the proposed change to EPA, as specified in paragraph (b)(1) of this section.


(e) Data elements. Table 1 defines the data elements that must be provided for UCMR monitoring.


Table 1 to Paragraph (e)—Unregulated Contaminant Monitoring Reporting Requirements

Data element
Definition
1. Public Water System Identification (PWSID) CodeThe code used to identify each PWS. The code begins with the standard 2-character postal State abbreviation or Region code; the remaining 7 numbers are unique to each PWS in the State. The same identification code must be used to represent the PWS identification for all current and future UCMR monitoring.
2. Public Water System NameUnique name, assigned once by the PWS.
3. Public Water System Facility Identification CodeAn identification code established by the State or, at the State’s discretion, by the PWS, following the format of a 5-digit number unique within each PWS for each applicable facility (i.e., for each source of water, treatment plant, distribution system, or any other facility associated with water treatment or delivery). The same identification code must be used to represent the facility for all current and future UCMR monitoring.
4. Public Water System Facility NameUnique name, assigned once by the PWS, for every facility ID (e.g., Treatment Plant).
5. Public Water System Facility TypeThat code that identifies that type of facility as either:

CC = Consecutive connection.

SS = Sampling station.

TP = Treatment plant.

OT = Other.
6. Water Source TypeThe type of source water that supplies a water system facility. Systems must report one of the following codes for each sampling location:
SW = Surface water (to be reported for water facilities that are served entirely by a surface water source during the 12-month period).
GU = Ground water under the direct influence of surface water (to be reported for water facilities that are served all or in part by ground water under the direct influence of surface water at any time during the 12-month sampling period), and are not served at all by surface water during this period.
MX = Mixed water (to be reported for water facilities that are served by a mix of surface water, ground water, and/or ground water under the direct influence of surface water during the 12-month period).
GW = Ground water (to be reported for water facilities that are served entirely by a ground water source during the 12-month period).
7. Sampling Point Identification CodeAn identification code established by the State, or at the State’s discretion, by the PWS, that uniquely identifies each sampling point. Each sampling code must be unique within each applicable facility, for each applicable sampling location (i.e., entry point to the distribution system). The same identification code must be used to represent the sampling location for all current and future UCMR monitoring.
8. Sampling Point NameUnique sample point name, assigned once by the PWS, for every sample point ID (e.g., Entry Point).
9. Sampling Point Type CodeA code that identifies the location of the sampling point as:

EP = Entry point to the distribution system.
10. Disinfectant TypeAll of the disinfectants/oxidants that have been added prior to and at the entry point to the distribution system. Please select all that apply:
PEMB = Permanganate.
HPXB = Hydrogen peroxide.
CLGA = Gaseous chlorine.
CLOF = Offsite generated hypochlorite (stored as a liquid form).
CLON = Onsite generated hypochlorite.
CAGC = Chloramine (formed with gaseous chlorine).
CAOF = Chloramine (formed with offsite hypochlorite).
CAON = Chloramine (formed with onsite hypochlorite).
CLDB = Chlorine dioxide.
OZON = Ozone.
ULVL = Ultraviolet light.
OTHD = All other types of disinfectant/oxidant.
NODU = No disinfectant/oxidant used.
11. Treatment InformationTreatment information associated with the sample point. Please select all that apply.
CON = Conventional (non-softening, consisting of at least coagulation/sedimentation basins and filtration).
SFN = Softening.
RBF = River bank filtration.
PSD = Pre-sedimentation.
INF = In-line filtration.
DFL = Direct filtration.
SSF = Slow sand filtration.
BIO = Biological filtration (operated with an intention of maintaining biological activity within filter).
UTR = Unfiltered treatment for surface water source.
GWD = Groundwater system with disinfection only.
PAC = Application of powder activated carbon.
GAC = Granular activated carbon adsorption (not part of filters in CON, SFN, INF, DFL, or SSF).
AIR = Air stripping (packed towers, diffused gas contactors).
POB = Pre-oxidation with chlorine (applied before coagulation for CON or SFN plants or before filtration for other filtration plants).
MFL = Membrane filtration.
IEX = Ionic exchange.
DAF = Dissolved air floatation.
CWL = Clear well/finished water storage without aeration.
CWA = Clear well/finished water storage with aeration.
ADS = Aeration in distribution system (localized treatment).
OTH = All other types of treatment.
NTU = No treatment used.
DKN = Do not know.
12. Sample Collection DateThe date the sample is collected, reported as 4-digit year, 2-digit month, and 2-digit day (YYYYMMDD).
13. Sample Identification CodeAn alphanumeric value up to 30 characters assigned by the laboratory to uniquely identify containers, or groups of containers, containing water samples collected at the same sampling location for the same sampling date.
14. ContaminantThe unregulated contaminant for which the sample is being analyzed.
15. Analytical Method CodeThe identification code of the analytical method used.
16. Extraction Batch Identification CodeLaboratory assigned extraction batch ID. Must be unique for each extraction batch within the laboratory for each method. For CCC samples report the Analysis Batch Identification Code as the value for this field. For methods without an extraction batch, leave this field null.
17. Extraction DateDate for the start of the extraction batch (YYYYMMDD). For methods without an extraction batch, leave this field null.
18. Analysis Batch Identification CodeLaboratory assigned analysis batch ID. Must be unique for each analysis batch within the laboratory for each method.
19. Analysis DateDate for the start of the analysis batch (YYYYMMDD).
20. Sample Analysis TypeThe type of sample collected and/or prepared, as well as the fortification level. Permitted values include:

CCCL = MRL level continuing calibration check; a calibration standard containing the contaminant, the internal standard, and surrogate analyzed to verify the existing calibration for those contaminants.
CCCM = Medium level continuing calibration check; a calibration standard containing the contaminant, the internal standard, and surrogate analyzed to verify the existing calibration for those contaminants.
CCCH = High level continuing calibration check; a calibration standard containing the contaminant, the internal standard, and surrogate analyzed to verify the existing calibration for those contaminants.
FS = Field sample; sample collected and submitted for analysis under this final rule.
LFB = Laboratory fortified blank; an aliquot of reagent water fortified with known quantities of the contaminants and all preservation compounds.
LRB = Laboratory reagent blank; an aliquot of reagent water treated exactly as a field sample, including the addition of preservatives, internal standards, and surrogates to determine if interferences are present in the laboratory, reagents, or other equipment.
LFSM = Laboratory fortified sample matrix; a UCMR field sample with a known amount of the contaminant of interest and all preservation compounds added.
LFSMD = Laboratory fortified sample matrix duplicate; duplicate of the laboratory fortified sample matrix.
QCS = Quality control sample; a sample prepared with a source external to the one used for initial calibration and CCC. The QCS is used to check calibration standard integrity.
FRB = Field reagent blank; an aliquot of reagent water treated as a sample including exposure to sampling conditions to determine if interferences or contamination are present from sample collection through analysis.
21. Analytical Result—SignA value indicating whether the sample analysis result was:

((=) “equal to” means the contaminant was detected at the level reported in “Analytical Result— Measured Value.”
22. Analytical Result—Measured ValueThe actual numeric value of the analytical results for: Field samples; laboratory fortified matrix samples; laboratory fortified sample matrix duplicates; and concentration fortified.
23. Additional ValueRepresents the true value or the fortified concentration for spiked samples for QC Sample Analysis Types (CCCL, CCCM, CCCH, QCS, LFB, LFSM, and LFSMD).
24. Laboratory Identification CodeThe code, assigned by EPA, used to identify each laboratory. The code begins with the standard two-character State postal abbreviation; the remaining five numbers are unique to each laboratory in the State.
25. Sample Event CodeA code assigned by the PWS for each sample event. This will associate samples with the PWS monitoring plan to allow EPA to track compliance and completeness. Systems must assign the following codes:
SE1, SE2, SE3, and SE4—Represent samples collected to meet UCMR Assessment Monitoring requirements; where “SE1” and “SE2” represent the first and second sampling period for all water types; and “SE3” and “SE4” represent the third and fourth sampling period for SW, GU, and MX sources only.
26. Historical Information for Contaminant Detections and TreatmentA yes or no answer provided by the PWS for each entry point to the distribution system.

Question: Have you tested for the contaminant in your drinking water in the past?

YES = If yes, did you modify your treatment and if so, what types of treatment did you implement? Select all that apply.
PAC = Application of powder activated carbon.
GAC = Granular activated carbon adsorption (not part of filters in CON, SFN, INF, DFL, or SSF).
IEX = Ionic exchange.
NRO = Nanofiltration and reverse osmosis.
OZN = Ozone.
BAC = Biologically active carbon.
MFL = Membrane filtration.
UVL = Ultraviolet light.
OTH = Other.
NMT = Not modified after testing.
NO = Have never tested for the contaminant.
DK = Do not know.
27. Potential PFAS SourcesA yes or no answer provided by the PWS for each entry point to the distribution system.

Question: Are you aware of any potential current and/or historical sources of PFAS that may have impacted the drinking water sources at your water system?
YES = If yes, select all that apply:
MB = Military base.
FT = Firefighting training school.
AO = Airport operations.
CW = Car wash or industrial launderers.
PS = Public safety activities (e.g., fire and rescue services).
WM = Waste management.
HW = Hazardous waste collection, treatment, and disposal.
UW = Underground injection well.
SC = Solid waste collection, combustors, incinerators.
MF = Manufacturing.
FP = Food packaging.
TA = Textile and apparel (e.g., stain- and water-resistant, fiber/thread, carpet, house furnishings, leather).
PP = Paper.
CC = Chemical.
PR = Plastics and rubber products.
MM = Machinery.
CE = Computer and electronic products.
FM = Fabricated metal products (e.g., nonstick cookware).
PC = Petroleum and coal products.
FF = Furniture.
OG = Oil and gas production.
UT = Utilities (e.g., sewage treatment facilities).
CT = Construction (e.g., wood floor finishing, electrostatic painting).
OT = Other.
NO = Not aware of any potential current and/or historical sources.
DK = Do not know.

[72 FR 389, Jan. 4, 2007, as amended at 77 FR 26096, May 2, 2012; 81 FR 92684, Dec. 20, 2016; 86 FR 73151, Dec. 27, 2021; 87 FR 3679, Jan. 25, 2022]


Subpart E—Special Regulations, Including Monitoring

§ 141.40 Monitoring requirements for unregulated contaminants.

(a) General applicability. This section specifies the monitoring and quality control requirements that must be followed if you own or operate a public water system (PWS) that is subject to the Unregulated Contaminant Monitoring Regulation (UCMR), as specified in paragraphs (a)(1) and (2) of this section. In addition, this section specifies the UCMR requirements for State and Tribal participation. For the purposes of this section, PWS “population served,” “State,” ” PWS Official,” “PWS Technical Contact,” and “finished water” apply as defined in § 141.35(a). The determination of whether a PWS is required to monitor under this rule is based on the type of system (e.g., community water system, non-transient non-community water system, etc.), and its retail population, as indicated by SDWIS/Fed on February 1, 2021 or subsequent corrections from the State.


(1) Applicability to transient non-community systems. If you own or operate a transient non-community water system, you are not subject to monitoring requirements in this section.


(2) Applicability to community water systems and non-transient non-community water systems—(i) Large systems. If you own or operate a retail PWS (other than a transient non-community system) that serves more than 10,000 people, you must monitor according to the specifications in this paragraph (a)(2)(i). If you believe that your applicability status is different than EPA has specified in the notification letter that you received, or if you are subject to UCMR requirements and you have not been notified by either EPA or your State, you must report to EPA, as specified in § 141.35(b)(2) or (c)(4).


(A) Assessment monitoring. You must monitor for the contaminants on List 1, per Table 1, UCMR Contaminant List, in paragraph (a)(3) of this section. If you serve a retail population of more than 10,000 people, you are required to perform this monitoring regardless of whether you have been notified by the State or EPA.


(B) Screening Survey. You must monitor for the unregulated contaminants on List 2 (Screening Survey) of Table 1, as specified in paragraph (a)(3) of this section, if your system serves 10,001 to 100,000 people and you are notified by EPA or your State that you are part of the State Monitoring Plan for Screening Survey testing. If your system serves more than 100,000 people, you are required to conduct this Screening Survey testing regardless of whether you have been notified by the State or EPA.


(C) Pre-Screen Testing. You must monitor for the unregulated contaminants on List 3 of Table 1, in paragraph (a)(3) of this section, if notified by your State or EPA that you are part of the Pre-Screen Testing.


(ii) Small systems. EPA will provide sample containers, provide pre-paid air bills for shipping the sampling materials, conduct the laboratory analysis, and report and review monitoring results for all small systems selected to conduct monitoring under paragraphs (a)(2)(ii)(A) through (C) of this section. If you own or operate a PWS (other than a transient non-community water system) that serves a retail population of 10,000 or fewer people and you are notified of monitoring requirements by the State or EPA, you must monitor as follows:


(A) Assessment Monitoring. You must monitor for the contaminants on List 1 per table 1 to paragraph (a)(3) if you are notified by your State or EPA that you are part of the State Monitoring Plan for Assessment Monitoring.


(B) Screening Survey. You must monitor for the unregulated contaminants on List 2 of Table 1, in paragraph (a)(3) of this section, if notified by your State or EPA that you are part of the State Monitoring Plan for the Screening Survey.


(C) Pre-screen testing. You must monitor for the contaminants on List 3 of Table 1, in paragraph (a)(3) of this section if you are notified by your State or EPA that you are part of the State Monitoring Plan for Pre-Screen Testing.


(3) Analytes to be monitored. Lists 1, 2, and 3 contaminants are provided in table 1 to paragraph (a)(3):


Table 1 to Paragraph (a)(3)—UCMR Contaminant List

1—Contaminant
2—CASRN
3—Analytical

methods
a
4—Minimum

reporting level
b
5—Sampling

location
c
6—Period during

which sample

collection

to be completed
List 1: Assessment Monitoring
Per- and Polyfluoroalkyl Substances (PFAS)
11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)763051-92-9EPA 5330.005 µg/LEPTDS1/1/2023-12/31/2025
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)39108-34-4EPA 5330.005 µg/LEPTDS1/1/2023-12/31/2025
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)757124-72-4EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)27619-97-2EPA 5330.005 µg/LEPTDS1/1/2023-12/31/2025
4,8-dioxa-3H-perfluorononanoic acid (ADONA)919005-14-4EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)756426-58-1EPA 5330.002 µg/LEPTDS1/1/2023-12/31/2025
hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX)13252-13-6EPA 5330.005 µg/LEPTDS1/1/2023-12/31/2025
nonafluoro-3,6-dioxaheptanoic acid (NFDHA)151772-58-6EPA 5330.02 µg/LEPTDS1/1/2023-12/31/2025
perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)113507-82-7EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluoro-3-methoxypropanoic acid (PFMPA)377-73-1EPA 5330.004 µg/LEPTDS1/1/2023-12/31/2025
perfluoro-4-methoxybutanoic acid (PFMBA)863090-89-5EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluorobutanesulfonic acid (PFBS)375-73-5EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluorobutanoic acid (PFBA)375-22-4EPA 5330.005 µg/LEPTDS1/1/2023-12/31/2025
perfluorodecanoic acid (PFDA)335-76-2EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluorododecanoic acid (PFDoA)307-55-1EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluoroheptanesulfonic acid (PFHpS)375-92-8EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluoroheptanoic acid (PFHpA)375-85-9EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluorohexanesulfonic acid (PFHxS)355-46-4EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluorohexanoic acid (PFHxA)307-24-4EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluorononanoic acid (PFNA)375-95-1EPA 5330.004 µg/LEPTDS1/1/2023-12/31/2025
perfluorooctanesulfonic acid (PFOS)1763-23-1EPA 5330.004 µg/LEPTDS1/1/2023-12/31/2025
perfluorooctanoic acid (PFOA)335-67-1EPA 5330.004 µg/LEPTDS1/1/2023-12/31/2025
perfluoropentanesulfonic acid (PFPeS)2706-91-4EPA 5330.004 µg/LEPTDS1/1/2023-12/31/2025
perfluoropentanoic acid (PFPeA)2706-90-3EPA 5330.003 µg/LEPTDS1/1/2023-12/31/2025
perfluoroundecanoic acid (PFUnA)2058-94-8EPA 5330.002 µg/LEPTDS1/1/2023-12/31/2025
n-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)2991-50-6EPA 537.10.005 µg/LEPTDS1/1/2023-12/31/2025
n-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)2355-31-9EPA 537.10.006 µg/LEPTDS1/1/2023-12/31/2025
perfluorotetradecanoic acid (PFTA)376-06-7EPA 537.10.008 µg/LEPTDS1/1/2023-12/31/2025
perfluorotridecanoic acid (PFTrDA)72629-94-8EPA 537.10.007 µg/LEPTDS1/1/2023-12/31/2025
Metal/Pharmaceutical
Lithium7439-93-2EPA 200.7, SM 3120 B, ASTM D1976-209 µg/LEPTDS1/1/2023-12/31/2025
List 2: Screening Survey
ReservedReservedReservedReservedReservedReserved
List 3: Pre-Screen Testing
ReservedReservedReservedReservedReservedReserved

Column headings are:

1—Contaminant: The name of the contaminant to be analyzed.

2—CASRN (Chemical Abstracts Service Registry Number) or Identification Number: A unique number identifying the chemical contaminants.

3—Analytical Methods: Method numbers identifying the methods that must be used to test the contaminants.

4—Minimum Reporting Level (MRL): The value and unit of measure at or above which the concentration of the contaminant must be measured using the approved analytical methods. If EPA determines, after the first six months of monitoring that the specified MRLs result in excessive resampling, EPA will establish alternate MRLs and will notify affected PWSs and laboratories of the new MRLs. N/A is defined as non-applicable.

5—Sampling Location: The locations within a PWS at which samples must be collected.

6—Period During Which Sample Collection to be Completed: The time period during which the sampling and testing will occur for the indicated contaminant.


a The analytical procedures shall be performed in accordance with the documents associated with each method, see paragraph (c) of this section.


b The MRL is the minimum concentration of each analyte that must be reported to EPA.


c Sampling must occur at your PWS’s entry points to the distribution system (EPTDSs), after treatment is applied, that represent each non-emergency water source in routine use over the 12-month period of monitoring. Systems that purchase water with multiple connections from the same wholesaler may select one representative connection from that wholesaler. The representative EPTDS must be a location within the purchaser’s water system. This EPTDS sampling location must be representative of the highest annual volume connections. If the connection selected as the representative EPTDS is not available for sampling, an alternate highest volume representative connection must be sampled. See 40 CFR 141.35(c)(3) for an explanation of the requirements related to the use of representative GW EPTDSs.


(4) Sampling requirements—(i) Large systems. If you serve more than 10,000 people and meet the UCMR applicability criteria specified in paragraph (a)(2)(i) of this section, you must comply with the requirements specified in paragraphs (a)(4)(i)(A) through (I) of this section. Your samples must be collected according to the schedule that you are assigned by EPA or your State, or the schedule that you revised using EPA’s electronic data reporting system on or before December 31, 2022. Your schedule must follow both the timing and frequency of monitoring specified in Tables 1 and 2 of this section.


(A) Sample collection period. You must collect the samples in one continuous 12-month period for List 1 Assessment Monitoring, and, if applicable, for List 2 Screening Survey, or List 3 Pre-Screen Testing, during the timeframe indicated in column 6 of table 1 to paragraph (a)(3) of this section. EPA or your State will specify the month(s) and year(s) in which your monitoring must occur. As specified in 40 CFR 141.35(c)(5), you must contact EPA if you believe you cannot collect samples according to your schedule.


(B) Frequency. You must collect the samples within the timeframe and according to the frequency specified by contaminant type and water source type for each sampling location, as specified in table 2 to this paragraph (a)(4)(i)(B). For the second or subsequent round of sampling, if a sample location is non-operational for more than one month before and one month after the scheduled sampling month (i.e., it is not possible for you to sample within the window specified in table 2), you must notify EPA as specified in 40 CFR 141.35(c)(5) to reschedule your sampling.


Table 2 to Paragraph (a)(4)(i)(B)—Monitoring Frequency by Contaminant and Water Source Types

Contaminant type
Water source type
Timeframe
Frequency
1
List 1 ContaminantsSurface water, Mixed, or GWUDI12 monthsYou must monitor for four consecutive quarters. Sample events must occur three months apart. (Example: If first monitoring is in January, the second monitoring must occur any time in April, the third any time in July, and the fourth any time in October).
Ground water12 monthsYou must monitor twice in a consecutive 12-month period. Sample events must occur 5-7 months apart. (Example: If the first monitoring event is in April, the second monitoring event must occur any time in September, October, or November.)


1 Systems must assign a sample event code for each contaminant listed in Table 1. Sample event codes must be assigned by the PWS for each sample event. For more information on sample event codes see 40 CFR 141.35(e) Table 1.


(C) Location. You must collect samples for each List 1 Assessment Monitoring contaminant, and, if applicable, for each List 2 Screening Survey, or List 3 Pre-Screen Testing contaminant, as specified in table 1 to paragraph (a)(3) of this section. Samples must be collected at each sample point that is specified in column 5 and footnote c of table 1 to paragraph (a)(3) of this section. If you are a GW system with multiple EPTDSs, and you request and receive approval from EPA or the State for sampling at representative EPTDS(s), as specified in 40 CFR 141.35(c)(3), you must collect your samples from the approved representative sampling location(s).


(D) Sampling instructions. For each List 1 Assessment Monitoring contaminant, and, if applicable, for each List 2 Screening Survey, or List 3 Pre-Screen Testing contaminant, you must follow the sampling procedure for the method specified in column 3 of Table 1, in paragraph (a)(3) of this section. In addition, you must not composite (that is, combine, mix, or blend) the samples; you must collect and preserve each sample separately.


(E) Sample collection and shipping time. If you must ship the samples for analysis, you must collect the samples early enough in the day to allow adequate time to send the samples for overnight delivery to the laboratory. You should not collect samples on Friday, Saturday, or Sunday because sampling on these days may not allow samples to be shipped and received at the laboratory at the required temperature, unless you have made special arrangements with your laboratory to receive the samples.


(F) Analytical methods. For each contaminant, you must use the respective analytical methods for List 1, and, if applicable, for List 2, or List 3 that are specified in column 3 of Table 1, in paragraph (a)(3) of this section; report values at or above the minimum reporting levels for List 1, and, if applicable, for List 2 Screening Survey, or List 3 Pre-Screen Testing, that are specified in column 4 of Table 1, in paragraph (a)(3) of this section; and conduct the quality control procedures specified in paragraph (a)(5) of this section.


(G) Laboratory errors or sampling deviations. If the laboratory data do not meet the required QC criteria, as specified in paragraph (a)(5) of this section, or you do not follow the required sampling procedures, as specified in paragraphs (a)(4) of this section, you must resample within 30 days of being informed or becoming aware of these facts. This resampling is not for the purpose of confirming previous results, but to correct the sampling or laboratory error. All systems must report the results obtained from the first sampling for each sampling period, except for cases of sampling or laboratory errors. For the purposes of this rule, no samples are to be recollected for the purposes of confirming the results observed in a previous sampling.


(H) Analysis. For the List 1 contaminants, and, if applicable, List 2 Screening Survey, or List 3 Pre-Screen Testing contaminants, identified in Table 1, paragraph (a)(3) of this section, you must arrange for testing by a laboratory that has been approved by EPA according to requirements in paragraph (a)(5)(ii) of this section.


(I) Review and reporting of results. After you have received the laboratory results, you must review, approve, and submit the system information, and sample collection data and test results. You must report the results as provided in § 141.35(c)(6).


(ii) Small systems. If you serve a population of 10,000 or fewer people and are notified that you are part of the State Monitoring Plan, you must comply with the requirements specified in paragraphs (a)(4)(ii)(A) through (H) of this section. If EPA or the State informs you that they will be collecting your UCMR samples, you must assist them in identifying the appropriate sampling locations and in collecting the samples.


(A) Sample collection and frequency. You must collect samples at the times specified for you by the State or EPA. Your schedule must follow both the timing of monitoring specified in table 1 to paragraph (a)(3) of this section, List 1, and, if applicable, List 2, or List 3, and the frequency of monitoring in table 2 to paragraph (a)(4)(i)(B) of this section.


(B) Location. You must collect samples at the locations specified for you by the State or EPA.


(C) Sample kits. You must store and maintain the sample collection kits sent to you by the UCMR Sampling Coordinator in accordance with the kit’s instructions. The sample kit will include all necessary containers, packing materials and cold packs, instructions for collecting the sample and sample treatment (such as dechlorination or preservation), report forms for each sample, contact name and telephone number for the laboratory, and a prepaid return shipping docket and return address label. If any of the materials listed in the kit’s instructions are not included in the kit or arrive damaged, you must notify the UCMR Sampling Coordinator who sent you the sample collection kits.


(D) Sampling instructions. You must comply with the instructions sent to you by the State or EPA concerning the use of containers, collection (how to fill the sample bottle), dechlorination and/or preservation, and sealing and preparation of sample and shipping containers for shipment. You must not composite (that is, combine, mix, or blend) the samples. You also must collect, preserve, and test each sample separately. You must also comply with the instructions sent to you by the UCMR Sampling Coordinator concerning the handling of sample containers for specific contaminants.


(E) Sampling deviations. If you do not collect a sample according to the instructions provided to you for a listed contaminant, you must report the deviation within 7 days of the scheduled monitoring on the sample reporting form, as specified in § 141.35(d)(2). You must resample following instructions that you will be sent from the UCMR Sampling Coordinator or State. A copy of the form must be sent to the laboratory with the recollected samples, and to the UCMR Sampling Coordinator.


(F) [Reserved]


(G) Sampling forms. You must completely fill out each of the sampling forms and bottles sent to you by the UCMR Sampling Coordinator, including data elements listed in § 141.35(e) for each sample, as specified in § 141.35(d)(2). You must sign and date the sampling forms.


(H) Sample collection and shipping. You must collect the samples early enough in the day to allow adequate time to send the samples for overnight delivery to the laboratory. You should not collect samples on Friday, Saturday, or Sunday because sampling on these days may not allow samples to be shipped and received at the laboratory at the required temperature unless you have made special arrangements with EPA for the laboratory to receive the samples. Once you have collected the samples and completely filled in the sampling forms, you must send the samples and the sampling forms to the laboratory designated on the air bill.


(5) Quality control requirements. If your system serves more than 10,000 people, you must ensure that the quality control requirements listed below are met during your sampling procedures and by the laboratory conducting your analyses. You must also ensure that all method quality control procedures and all UCMR quality control procedures are followed.


(i) Sample collection/preservation. You must follow the sample collection and preservation requirements for the specified method for each of the contaminants in Table 1, in paragraph (a)(3) of this section. These requirements specify sample containers, collection, dechlorination, preservation, storage, sample holding time, and extract storage and/or holding time that you must assure that the laboratory follow.


(ii) Laboratory approval for Lists 1, List 2 and List 3. To be approved to conduct UCMR testing, the laboratory must be certified under § 141.28 for one or more compliance analyses; demonstrate for each analytical method it plans to use for UCMR testing that it can meet the Initial Demonstration of Capability (IDC) requirements detailed in the analytical methods specified in column 3 of Table 1, in paragraph (a)(3) of this section; and successfully participate in the UCMR Proficiency Testing (PT) Program administered by EPA for each analytical method it plans to use for UCMR testing. UCMR laboratory approval decisions will be granted on an individual method basis for the methods listed in column 3 of Table 1 in paragraph (a)(3) of this section for List 1, List 2, and List 3 contaminants. Laboratory approval is contingent upon the capability of the laboratory to post monitoring data to the EPA electronic data reporting system. To participate in the UCMR Laboratory Approval Program, the laboratory must register and complete the necessary application materials by August 1, 2022. Correspondence must be addressed to: UCMR Laboratory Approval Coordinator, USEPA, Technical Support Center, 26 West Martin Luther King Drive, (MS 140), Cincinnati, Ohio 45268; or emailed to EPA at: [email protected].


(iii) Minimum Reporting Level. The MRL is defined by EPA as the quantitation limit achievable, with 95 percent confidence, by 75 percent of laboratories nationwide, assuming the use of good instrumentation and experienced analysts.


(A) Validation of laboratory performance. Your laboratory must be capable of quantifying each contaminant listed in Table 1, at or below the MRL specified in column 4 of Table 1, in paragraph (a)(3) of this section. You must ensure that the laboratory completes and has on file and available for your inspection, records of two distinct procedures. First, your laboratory must have conducted an IDC involving replicate analyses at or below the MRL as described in this paragraph. Second, for each day that UCMR analyses are conducted by your laboratory, a validation of its ability to quantify each contaminant, at or below the MRL specified in column 4 of Table 1, in paragraph (a)(3) of this section, following the procedure listed in paragraph (a)(5)(iii)(B) of this section, must be performed. The procedure for initial validation of laboratory performance at or below the MRL is as follows:


(1) All laboratories performing analysis under UCMR must demonstrate that they are capable of meeting data quality objectives at or below the MRL listed in Table 1, column 4, in paragraph (a)(3) of this section.


(2) The MRL, or any concentration below the MRL, at which performance is being evaluated, must be contained within the range of calibration. The calibration curve regression model and the range of calibration levels that are used in these performance validation steps must be used in all routine sample analyses used to comply with this regulation. Only straight line or quadratic regression models are allowed. The use of either weighted or unweighted models is permitted. The use of cubic regression models is not permitted.


(3) Replicate analyses of at least seven (7) fortified samples in reagent water must be performed at or below the MRL for each analyte, and must be processed through the entire method procedure (i.e., including extraction, where applicable, and with all preservatives).


(4) A prediction interval of results (PIR), which is based on the estimated arithmetic mean of analytical results and the estimated sample standard deviation of measurement results, must be determined by Equation 1:





Where:

t is the Student’s t value with df degrees of freedom and confidence level (1-α),

s is the sample standard deviation of n replicate samples fortified at the MRL,

n is the number of replicates.

(5) The values needed to calculate the PIR using Equation 1 are: Number of replicates (n); Student’s t value with a two-sided 99% confidence level for n number of replicates; the average (mean) of at least seven replicates; and the sample standard deviation. Factor 1 is referred to as the Half Range PIR (HRPIR).




For a certain number of replicates and for a certain confidence level in Student’s t, this factor



is constant, and can be tabulated according to replicate number and confidence level for the Student’s t. Table 3 in this paragraph lists the constant factor (C) for replicate sample numbers 7 through 10 with a confidence level of 99% for Student’s t.

(6) The HRPIR is calculated by Equation 2:




(7) The PIR is calculated by Equation 3:




Table 3—The Constant Factor (C) to be Multiplied by the Standard Deviation to Determine the Half Range Interval of the PIR (Student’s t 99% Confidence Level)
a

Replicates
Degrees of freedom
Constant factor (C) to be multiplied by the standard

deviation
763.963
873.711
983.536
1093.409


a The critical t-value for a two-sided 99% confidence interval is equivalent to the critical t-value for a one-sided 99.5% confidence interval, due to the symmetry of the t-distribution. PIR = Prediction Interval of Results.


(8) The lower and upper result limits of the PIR must be converted to percent recovery of the concentration being tested. To pass criteria at a certain level, the PIR lower recovery limits cannot be lower than the lower recovery limits of the QC interval (50%), and the PIR upper recovery limits cannot be greater than the upper recovery limits of the QC interval (150%). When either of the PIR recovery limits falls outside of either bound of the QC interval of recovery (higher than 150% or less than 50%), laboratory performance is not validated at the concentration evaluated. If the PIR limits are contained within both bounds of the QC interval, laboratory performance is validated for that analyte.


(B) Quality control requirements for validation of laboratory performance at or below the MRL.


(1) You must ensure that the calibration curve regression model and that the range of calibration levels that are used in these performance validation steps are used in future routine sample analysis. Only straight line or quadratic regression models are allowed. The use of either weighted or unweighted models is permitted. The use of cubic regression models is not permitted.


(2) You must ensure, once your laboratory has performed an IDC as specified in each analytical method (demonstrating that DQOs are met at or below an MRL), that a daily performance check is performed for each analyte and method. A single laboratory blank, fortified at or below the MRL for each analyte, must be processed through the entire method procedure. The measured concentration for each analyte must be converted to a percent recovery, and if the recovery is within 50%-150% (inclusive), the daily performance of the laboratory has been validated. The results for any analyte for which 50%-150% recovery cannot be demonstrated during the daily check are not valid. Laboratories may elect to re-run the daily performance check sample if the performance for any analyte or analytes cannot be validated. If performance is validated for these analytes, the laboratory performance is considered validated. Alternatively, the laboratory may re-calibrate and repeat the performance validation process for all analytes.


(iv) [Reserved]


(v) Method defined quality control. You must ensure that your laboratory analyzes Laboratory Fortified Blanks and conducts Laboratory Performance Checks, as appropriate to the method’s requirements, for those methods listed in column 3 in table 1 to paragraph (a)(3) of this section. Each method specifies acceptance criteria for these QC checks.


(vi) Reporting. You must require your laboratory, on your behalf, to post and approve these data in EPA’s electronic data reporting system, accessible at https://www.epa.gov/dwucmr, for your review within 90 days from the sample collection date. You then have 30 days from when the laboratory posts and approves your data to review, approve, and submit the data to the State and EPA, via the agency’s electronic data reporting system. If you do not electronically approve and submit the laboratory data to EPA within 30 days of the laboratory posting approved data, the data will be considered approved by you and available for State and EPA review.


(6) Violation of this rule—(i) Monitoring violations. Any failure to monitor in accordance with § 141.40(a)(3)-(5) is a monitoring violation.


(ii) Reporting violations. Any failure to report in accordance with § 141.35 is a reporting violation.


(b) Petitions and waivers by States—(1) Governors’ petition for additional contaminants. The Safe Drinking Water Act allows Governors of seven (7) or more States to petition the EPA Administrator to add one or more contaminants to the UCMR Contaminant List in paragraph (a)(3) of this section. The petition must clearly identify the reason(s) for adding the contaminant(s) to the monitoring list, including the potential risk to public health, particularly any information that might be available regarding disproportional risks to the health and safety of children, the expected occurrence documented by any available data, any analytical methods known or proposed to be used to test for the contaminant(s), and any other information that could assist the Administrator in determining which contaminants present the greatest public health concern and should, therefore, be included on the UCMR Contaminant List in paragraph (a)(3) of this section.


(2) State-wide waivers. A State can waive monitoring requirements only with EPA approval and under very limited conditions. Conditions and procedures for obtaining a waiver are as follows:


(i) Application. A State may apply to EPA for a State-wide waiver from the unregulated contaminant monitoring requirements for PWSs serving more than 10,000 people. To apply for such a waiver, the State must submit an application to EPA that includes the following information: The list of contaminants on the UCMR Contaminant List for which a waiver is requested, along with documentation for each contaminant in the request demonstrating that the contaminants or their parent compounds do not occur naturally in the State, and certifying that during the past 15 years they have not been used, applied, stored, disposed of, released, or detected in the source waters or distribution systems in the State.


(ii) Approval. EPA will review State applications and notify the State whether it accepts or rejects the request. The State must receive written approval from EPA before issuing a State-wide waiver.


(c) Incorporation by reference. The standards required in this section are incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. All approved material is available for inspection at U.S. Environmental Protection Agency, Water Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. NW, Washington, DC 20004, (202) 566-1744, email [email protected], or go to https://www.epa.gov/dockets/epa-docket-center-reading-room, and is available from the sources indicated elsewhere in this paragraph. The material is also available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email [email protected], or go to www.archives.gov/federal-register/cfr/ibr-locations.html.


(1) U.S. Environmental Protection Agency, EPA West, Room 3334, 1301 Constitution Ave. NW, Washington, DC 20004; telephone: (202) 566-1744.


(i) Method 200.7, “Determination of Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry,” Revision 4.4, EMMC Version, 1994. Available at https://www.epa.gov/esam/method-2007-determination-metals-and-trace-elements-water-and-wastes-inductively-coupled-plasma.


(ii) Method 537.1, “Determination of Selected Per- and Polyfluorinated Alkyl Substances in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry,” Version 2.0, 2020. Available at https://www.epa.gov/water-research/epa-drinking-water-research-methods.


(iii) Method 533, “Determination of Per- and Polyfluoroalkyl Substances in Drinking Water by Isotope Dilution Anion Exchange Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry,” November 2019, EPA 815-B-19-020. Available at https://www.epa.gov/dwanalyticalmethods.


(2) American Public Health Association, 800 I Street NW, Washington, DC 20001-3710; telephone: (202) 777-2742; email: [email protected]; www.apha.org.


(i) “Standard Methods for the Examination of Water & Wastewater,” 23rd edition (2017).


(A) SM 3120 B, “Metals by Plasma Emission Spectroscopy (2017): Inductively Coupled Plasma (ICP) Method.”


(B) [Reserved]


(ii) “Standard Methods Online,” approved 1999; https://www.standardmethods.org.


(A) SM 3120 B, “Metals by Plasma Emission Spectroscopy: Inductively Coupled Plasma (ICP) Method,” revised December 14, 2020.


(B) [Reserved]


(3) ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959; telephone: (610) 832-9500; email: [email protected]; www.astm.org.


(i) ASTM D1976-20, “Standard Test Method for Elements in Water by Inductively-Coupled Plasma Atomic Emission Spectroscopy,” approved May 1, 2020.


(ii) [Reserved]


[72 FR 393, Jan. 4, 2007; 72 FR 3916, Jan. 26, 2007, as amended at 77 FR 26098, May 2, 2012; 81 FR 92688, Dec. 20, 2016; 86 FR 73155, Dec. 27, 2021; 87 FR 3679, Jan. 25, 2022]


§ 141.41 Special monitoring for sodium.

(a) Suppliers of water for community public water systems shall collect and analyze one sample per plant at the entry point of the distribution system for the determination of sodium concentration levels; samples must be collected and analyzed annually for systems utilizing surface water sources in whole or in part, and at least every three years for systems utilizing solely ground water sources. The minimum number of samples required to be taken by the system shall be based on the number of treatment plants used by the system, except that multiple wells drawing raw water from a single aquifer may, with the State approval, be considered one treatment plant for determining the minimum number of samples. The supplier of water may be required by the State to collect and analyze water samples for sodium more frequently in locations where the sodium content is variable.


(b) The supplier of water shall report to EPA and/or the State the results of the analyses for sodium within the first 10 days of the month following the month in which the sample results were received or within the first 10 days following the end of the required monitoring period as stipulated by the State, whichever of these is first. If more than annual sampling is required the supplier shall report the average sodium concentration within 10 days of the month following the month in which the analytical results of the last sample used for the annual average was received. The supplier of water shall not be required to report the results to EPA where the State has adopted this regulation and results are reported to the State. The supplier shall report the results to EPA where the State has not adopted this regulation.


(c) The supplier of water shall notify appropriate local and State public health officials of the sodium levels by written notice by direct mail within three months. A copy of each notice required to be provided by this paragraph shall be sent to EPA and/or the State within 10 days of its issuance. The supplier of water is not required to notify appropriate local and State public health officials of the sodium levels where the State provides such notices in lieu of the supplier.


(d) Analyses for sodium shall be conducted as directed in § 141.23(k)(1).


[45 FR 57345, Aug. 27, 1980, as amended at 59 FR 62470, Dec. 5, 1994]


§ 141.42 Special monitoring for corrosivity characteristics.

(a)-(c) [Reserved]


(d) Community water supply systems shall identify whether the following construction materials are present in their distribution system and report to the State:



Lead from piping, solder, caulking, interior lining of distribution mains, alloys and home plumbing.

Copper from piping and alloys, service lines, and home plumbing.

Galvanized piping, service lines, and home plumbing.

Ferrous piping materials such as cast iron and steel.

Asbestos cement pipe.
In addition, States may require identification and reporting of other materials of construction present in distribution systems that may contribute contaminants to the drinking water, such as:


Vinyl lined asbestos cement pipe.

Coal tar lined pipes and tanks.
[45 FR 57346, Aug. 27, 1980; 47 FR 10999, Mar. 12, 1982, as amended at 59 FR 62470, Dec. 5, 1994]


Subpart F—Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals

§ 141.50 Maximum contaminant level goals for organic contaminants.

(a) MCLGs are zero for the following contaminants:


(1) Benzene


(2) Vinyl chloride


(3) Carbon tetrachloride


(4) 1,2-dichloroethane


(5) Trichloroethylene


(6) Acrylamide


(7) Alachlor


(8) Chlordane


(9) Dibromochloropropane


(10) 1,2-Dichloropropane


(11) Epichlorohydrin


(12) Ethylene dibromide


(13) Heptachlor


(14) Heptachlor epoxide


(15) Pentachlorophenol


(16) Polychlorinated biphenyls (PCBs)


(17) Tetrachloroethylene


(18) Toxaphene


(19) Benzo[a]pyrene


(20) Dichloromethane (methylene chloride)


(21) Di(2-ethylhexyl)phthalate


(22) Hexachlorobenzene


(23) 2,3,7,8-TCDD (Dioxin)


(b) MCLGs for the following contaminants are as indicated:


Contaminant
MCLG in mg/l
(1) 1,1-Dichloroethylene0.007
(2) 1,1,1-Trichloroethane0.20
(3) para-Dichlorobenzene0.075
(4) Aldicarb0.001
(5) Aldicarb sulfoxide0.001
(6) Aldicarb sulfone0.001
(7) Atrazine0.003
(8) Carbofuran0.04
(9) o-Dichlorobenzene0.6
(10) cis-1,2-Dichloroethylene0.07
(11) trans-1,2-Dichloroethylene0.1
(12) 2,4-D0.07
(13) Ethylbenzene0.7
(14) Lindane0.0002
(15) Methoxychlor0.04
(16) Monochlorobenzene0.1
(17) Styrene0.1
(18) Toluene1
(19) 2,4,5-TP0.05
(20) Xylenes (total)10
(21) Dalapon0.2
(22) Di(2-ethylhexyl)adipate.4
(23) Dinoseb.007
(24) Diquat.02
(25) Endothall.1
(26) Endrin.002
(27) Glyphosate.7
(28) Hexachlorocyclopentadiene.05
(29) Oxamyl (Vydate).2
(30) Picloram.5
(31) Simazine.004
(32) 1,2,4-Trichlorobenzene.07
(33) 1,1,2-Trichloroethane.003

[50 FR 46901, Nov. 13, 1985, as amended at 52 FR 20674, June 2, 1987; 52 FR 25716, July 8, 1987; 56 FR 3592, Jan. 30, 1991; 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992]


§ 141.51 Maximum contaminant level goals for inorganic contaminants.

(a) [Reserved]


(b) MCLGs for the following contaminants are as indicated:


Contaminant
MCLG (mg/l)
Antimony0.006
Arseniczero
1
Asbestos7 Million fibers/liter (longer than 10 µm).
Barium2
Beryllium.004
Cadmium0.005
Chromium0.1
Copper1.3
Cyanide (as free Cyanide).2
Fluoride4.0
Leadzero
Mercury0.002
Nitrate10 (as Nitrogen).
Nitrite1 (as Nitrogen).
Total Nitrate + Nitrite10 (as Nitrogen).
Selenium0.05
Thallium.0005


1 This value for arsenic is effective January 23, 2006. Until then, there is no MCLG.


[50 FR 47155, Nov. 14, 1985, as amended at 52 FR 20674, June 2, 1987; 56 FR 3593, Jan. 30, 1991; 56 FR 26548, June 7, 1991; 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 60 FR 33932, June 29, 1995; 66 FR 7063, Jan. 22, 2001]


§ 141.52 Maximum contaminant level goals for microbiological contaminants.

(a) MCLGs for the following contaminants are as indicated:


Contaminant
MCLG
(1) Giardia lambliazero
(2) Viruseszero
(3) Legionellazero
(4) Total coliforms (including fecal)zero
coliforms and Escherichia coli
(5) Cryptosporidiumzero
(6) Escherichia coli (E. coli)zero

(b) The MCLG identified in paragraph (a)(4) of this section is applicable until March 31, 2016. The MCLG identified in paragraph (a)(6) of this section is applicable beginning April 1, 2016.


[78 FR 10347, Feb. 13, 2013]


§ 141.53 Maximum contaminant level goals for disinfection byproducts.

MCLGs for the following disinfection byproducts are as indicated:


Disinfection byproduct
MCLG

(mg/L)
Bromodichloromethanezero
Bromoformzero
Bromatezero
Chlorite0.8
Chloroform0.07
Dibromochloromethane0.06
Dichloroacetic acidzero
Monochloroacetic acid0.07
Trichloroacetic acid0.02

[63 FR 69465, Dec. 16, 1998, as amended at 65 FR 34405, May 30, 2000; 71 FR 478, Jan. 4, 2006]


§ 141.54 Maximum residual disinfectant level goals for disinfectants.

MRDLGs for disinfectants are as follows:


Disinfectant residual
MRDLG(mg/L)
Chlorine4 (as Cl 2).
Chloramines4 (as Cl 2).
Chlorine dioxide0.8 (as ClO2)

[63 FR 69465, Dec. 16, 1998]


§ 141.55 Maximum contaminant level goals for radionuclides.

MCLGs for radionuclides are as indicated in the following table:


Contaminant
MCLG
1. Combined radium-226 and radium-228Zero.
2. Gross alpha particle activity (excluding radon and uranium)Zero.
3. Beta particle and photon radioactivityZero.
4. UraniumZero.

[65 FR 76748, Dec. 7, 2000]


Subpart G—National Primary Drinking Water Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels

§ 141.60 Effective dates.

(a) The effective dates for § 141.61 are as follows:


(1) The effective date for paragraphs (a)(1) through (a)(8) of § 141.61 is January 9, 1989.


(2) The effective date for paragraphs (a)(9) through (a)(18) and (c)(1) through (c)(18) of § 141.61 is July 30, 1992.


(3) The effective date for paragraphs (a)(19) through (a)(21), (c)(19) through (c)(25), and (c)(27) through (c)(33) of § 141.61 is January 17, 1994. The effective date of § 141.61(c)(26) is August 17, 1992.


(b) The effective dates for § 141.62 are as follows:


(1) The effective date of paragraph (b)(1) of § 141.62 is October 2, 1987.


(2) The effective date for paragraphs (b)(2) and (b)(4) through (b)(10) of § 141.62 is July 30, 1992.


(3) The effective date for paragraphs (b)(11) through (b)(15) of § 141.62 is January 17, 1994.


(4) The effective date for § 141.62(b)(16) is January 23, 2006.


[56 FR 3593, Jan. 30, 1991, as amended at 57 FR 31846, July 17, 1992; 59 FR 34324, July 1, 1994; 66 FR 7063, Jan. 22, 2001]


§ 141.61 Maximum contaminant levels for organic contaminants.

(a) The following maximum contaminant levels for organic contaminants apply to community and non-transient, non-community water systems.


CAS No.
Contaminant
MCL (mg/l)
(1) 75-01-4Vinyl chloride0.002
(2) 71-43-2Benzene0.005
(3) 56-23-5Carbon tetrachloride0.005
(4) 107-06-21,2-Dichloroethane0.005
(5) 79-01-6Trichloroethylene0.005
(6) 106-46-7para-Dichlorobenzene0.075
(7) 75-35-41,1-Dichloroethylene0.007
(8) 71-55-61,1,1-Trichloroethane0.2
(9) 156-59-2cis-1,2-Dichloroethylene0.07
(10) 78-87-51,2-Dichloropropane0.005
(11) 100-41-4Ethylbenzene0.7
(12) 108-90-7Monochlorobenzene0.1
(13) 95-50-1o-Dichlorobenzene0.6
(14) 100-42-5Styrene0.1
(15) 127-18-4Tetrachloroethylene0.005
(16) 108-88-3Toluene1
(17) 156-60-5trans-1,2-Dichloroethylene0.1
(18) 1330-20-7Xylenes (total)10
(19) 75-09-2Dichloromethane0.005
(20) 120-82-11,2,4-Trichloro- benzene.07
(21) 79-00-51,1,2-Trichloro- ethane.005

(b) The Administrator, pursuant to section 1412 of the Act, hereby identifies as indicated in the Table below granular activated carbon (GAC), packed tower aeration (PTA), or oxidation (OX) as the best technology treatment technique, or other means available for achieving compliance with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c) of this section:


BAT for Organic Contaminants Listed in § 141.61 (a) and (c)

CAS No.
Contaminant
GAC
PTA
OX
15972-60-8AlachlorX
116-06-3AldicarbX
1646-88-4Aldicarb sulfoneX
1646-87-3Aldicarb sulfoxideX
1912-24-9AtrazineX
71-43-2BenzeneXX
50-32-8Benzo[a]pyreneX
1563-66-2CarbofuranX
56-23-5Carbon tetrachlorideXX
57-74-9ChlordaneX
75-99-0DalaponX
94-75-72,4-DX
103-23-1Di (2-ethylhexyl) adipateXX
117-81-7Di (2-ethylhexyl) phthalateX
96-12-8Dibromochloropropane (DBCP)XX
95-50-1o-DichlorobenzeneXX
106-46-7para-DichlorobenzeneXX
107-06-21,2-DichloroethaneXX
75-35-41,1-DichloroethyleneXX
156-59-2cis-1,2-DichloroethyleneXX
156-60-5trans-1,2-DichloroethyleneXX
75-09-2DichloromethaneX
78-87-51,2-DichloropropaneXX
88-85-7DinosebX
85-00-7DiquatX
145-73-3EndothallX
72-20-8EndrinX
100-41-4EthylbenzeneXX
106-93-4Ethylene Dibromide (EDB)XX
1071-83-6GylphosateX
76-44-8HeptachlorX
1024-57-3Heptachlor epoxideX
118-74-1HexachlorobenzeneX
77-47-3HexachlorocyclopentadieneXX
58-89-9LindaneX
72-43-5MethoxychlorX
108-90-7MonochlorobenzeneXX
23135-22-0Oxamyl (Vydate)X
87-86-5PentachlorophenolX
1918-02-1PicloramX
1336-36-3Polychlorinated biphenyls (PCB)X
122-34-9SimazineX
100-42-5StyreneXX
1746-01-62,3,7,8-TCDD (Dioxin)X
127-18-4TetrachloroethyleneXX
108-88-3TolueneXX
8001-35-2ToxapheneX
93-72-12,4,5-TP (Silvex)X
120-82-11,2,4-TrichlorobenzeneXX
71-55-61,1,1-TrichloroethaneXX
79-00-51,1,2-TrichloroethaneXX
79-01-6TrichloroethyleneXX
75-01-4Vinyl chlorideX
1330-20-7XyleneXX

(c) The following maximum contaminant levels for synthetic organic contaminants apply to community water systems and non-transient, non-community water systems:


CAS No.
Contaminant
MCL (mg/l)
(1) 15972-60-8Alachlor0.002
(2) 116-06-3Aldicarb0.003
(3) 1646-87-3Aldicarb sulfoxide0.004
(4) 1646-87-4Aldicarb sulfone0.002
(5) 1912-24-9Atrazine0.003
(6) 1563-66-2Carbofuran0.04
(7) 57-74-9Chlordane0.002
(8) 96-12-8Dibromochloropropane0.0002
(9) 94-75-72,4-D0.07
(10) 106-93-4Ethylene dibromide0.00005
(11) 76-44-8Heptachlor0.0004
(12) 1024-57-3Heptachlor epoxide0.0002
(13) 58-89-9Lindane0.0002
(14) 72-43-5Methoxychlor0.04
(15) 1336-36-3Polychlorinated biphenyls0.0005
(16) 87-86-5Pentachlorophenol0.001
(17) 8001-35-2Toxaphene0.003
(18) 93-72-12,4,5-TP0.05
(19) 50-32-8Benzo[a]pyrene0.0002
(20) 75-99-0Dalapon0.2
(21) 103-23-1Di(2-ethylhexyl) adipate0.4
(22) 117-81-7Di(2-ethylhexyl) phthalate0.006
(23) 88-85-7Dinoseb0.007
(24) 85-00-7Diquat0.02
(25) 145-73-3Endothall0.1
(26) 72-20-8Endrin0.002
(27) 1071-53-6Glyphosate0.7
(28) 118-74-1Hexacholorbenzene0.001
(29) 77-47-4Hexachlorocyclopentadiene0.05
(30) 23135-22-0Oxamyl (Vydate)0.2
(31) 1918-02-1Picloram0.5
(32) 122-34-9Simazine0.004
(33) 1746-01-62,3,7,8-TCDD (Dioxin)3 × 10−8

[56 FR 3593, Jan. 30, 1991, as amended at 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 59 FR 34324, July 1, 1994]


§ 141.62 Maximum contaminant levels for inorganic contaminants.

(a) [Reserved]


(b) The maximum contaminant levels for inorganic contaminants specified in paragraphs (b) (2)-(6), (b)(10), and (b) (11)-(16) of this section apply to community water systems and non-transient, non-community water systems. The maximum contaminant level specified in paragraph (b)(1) of this section only applies to community water systems. The maximum contaminant levels specified in (b)(7), (b)(8), and (b)(9) of this section apply to community water systems; non-transient, non-community water systems; and transient non-community water systems.


Contaminant
MCL (mg/l)
(1) Fluoride4.0
(2) Asbestos7 Million Fibers/liter (longer than 10 µm).
(3) Barium2
(4) Cadmium0.005
(5) Chromium0.1
(6) Mercury0.002
(7) Nitrate10 (as Nitrogen)
(8) Nitrite1 (as Nitrogen)
(9) Total Nitrate and Nitrite10 (as Nitrogen)
(10) Selenium0.05
(11) Antimony0.006
(12) Beryllium0.004
(13) Cyanide (as free Cyanide)0.2
(14) [Reserved]
(15) Thallium0.002
(16) Arsenic0.010

(c) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment technique, or other means available for achieving compliance with the maximum contaminant levels for inorganic contaminants identified in paragraph (b) of this section, except fluoride:


BAT for Inorganic Compounds Listed in Section 141.62(b)

Chemical Name
BAT(s)
Antimony2,7
Arsenic
4		1, 2, 5, 6, 7, 9, 12
5
Asbestos2,3,8
Barium5,6,7,9
Beryllium1,2,5,6,7
Cadmium2,5,6,7
Chromium2,5,6
2,7
Cyanide5,7,13
Mercury2
1,4,6
1,7
1
Nickel5,6,7
Nitrate5,7,9
Nitrite5,7
Selenium1,2
3,6,7,9
Thallium1,5


1 BAT only if influent Hg concentrations ≤10µg/1.


2 BAT for Chromium III only.


3 BAT for Selenium IV only.


4 BATs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.


5 To obtain high removals, iron to arsenic ratio must be at least 20:1.


Key to BATS in Table


1 = Activated Alumina

2 = Coagulation/Filtration (not BAT for systems
3 = Direct and Diatomite Filtration

4 = Granular Activated Carbon

5 = Ion Exchange

6 = Lime Softening (not BAT for systems
7 = Reverse Osmosis

8 = Corrosion Control

9 = Electrodialysis

10 = Chlorine

11 = Ultraviolet

12 = Oxidation/Filtration

13 = Alkaline Chlorination (pH ≥8.5)

(d) The Administrator, pursuant to section 1412 of the Act, hereby identifies in the following table the affordable technology, treatment technique, or other means available to systems serving 10,000 persons or fewer for achieving compliance with the maximum contaminant level for arsenic:


Small System Compliance Technologies (SSCTs)
1 for Arsenic
2

Small system compliance technology
Affordable for listed small system categories
3
Activated Alumina (centralized)All size categories.
Activated Alumina (Point-of-Use)
4		All size categories.
Coagulation/Filtration
5		501-3,300, 3,301-10,000.
Coagulation-assisted Microfiltration501-3,300, 3,301-10,000.
Electrodialysis reversal
6		501-3,300, 3,301-10,000.
Enhanced coagulation/filtrationAll size categories
Enhanced lime softening (pH>10.5)All size categories.
Ion ExchangeAll size categories.
Lime Softening
5		501-3,300, 3,301-10,000.
Oxidation/Filtration
7		All size categories.
Reverse Osmosis (centralized)
6		501-3,300, 3,301-10,000.
Reverse Osmosis (Point-of-Use)
4		All size categories.


1 Section 1412(b)(4)(E)(ii) of SDWA specifies that SSCTs must be affordable and technically feasible for small systems.


2 SSCTs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.


3 The Act (ibid.) specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501, (ii) those serving more than 500, but fewer than 3,301, and (iii) those serving more than 3,300, but fewer than 10,001.


4 When POU or POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be provided by the water system to ensure adequate performance.


5 Unlikely to be installed solely for arsenic removal. May require pH adjustment to optimal range if high removals are needed.


6 Technologies reject a large volume of water—may not be appropriate for areas where water quantity may be an issue.


7 To obtain high removals, iron to arsenic ratio must be at least 20:1.


[56 FR 3594, Jan. 30, 1991, as amended at 56 FR 30280, July 1, 1991; 57 FR 31847, July 17, 1992; 59 FR 34325, July 1, 1994; 60 FR 33932, June 29, 1995; 66 FR 7063, Jan. 22, 2001; 68 FR 14506, Mar. 25, 2003; 69 FR 38855, June 29, 2004]


§ 141.63 Maximum contaminant levels (MCLs) for microbiological contaminants.

(a) Until March 31, 2016, the total coliform MCL is based on the presence or absence of total coliforms in a sample, rather than coliform density.


(1) For a system that collects at least 40 samples per month, if no more than 5.0 percent of the samples collected during a month are total coliform-positive, the system is in compliance with the MCL for total coliforms.


(2) For a system that collects fewer than 40 samples per month, if no more than one sample collected during a month is total coliform-positive, the system is in compliance with the MCL for total coliforms.


(b) Until March 31, 2016, any fecal coliform-positive repeat sample or E. coli-positive repeat sample, or any total coliform-positive repeat sample following a fecal coliform-positive or E. coli-positive routine sample, constitutes a violation of the MCL for total coliforms. For purposes of the public notification requirements in subpart Q of this part, this is a violation that may pose an acute risk to health.


(c) Beginning April 1, 2016, a system is in compliance with the MCL for E. coli for samples taken under the provisions of subpart Y of this part unless any of the conditions identified in paragraphs (c)(1) through (c)(4) of this section occur. For purposes of the public notification requirements in subpart Q of this part, violation of the MCL may pose an acute risk to health.


(1) The system has an E. coli-positive repeat sample following a total coliform-positive routine sample.


(2) The system has a total coliform-positive repeat sample following an E. coli-positive routine sample.


(3) The system fails to take all required repeat samples following an E. coli-positive routine sample.


(4) The system fails to test for E. coli when any repeat sample tests positive for total coliform.


(d) Until March 31, 2016, a public water system must determine compliance with the MCL for total coliforms in paragraphs (a) and (b) of this section for each month in which it is required to monitor for total coliforms. Beginning April 1, 2016, a public water system must determine compliance with the MCL for E. coli in paragraph (c) of this section for each month in which it is required to monitor for total coliforms.


(e) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant level for total coliforms in paragraphs (a) and (b) of this section and for achieving compliance with the maximum contaminant level for E. coli in paragraph (c) of this section:


(1) Protection of wells from fecal contamination by appropriate placement and construction;


(2) Maintenance of a disinfectant residual throughout the distribution system;


(3) Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, cross connection control, and continual maintenance of positive water pressure in all parts of the distribution system;


(4) Filtration and/or disinfection of surface water, as described in subparts H, P, T, and W of this part, or disinfection of ground water, as described in subpart S of this part, using strong oxidants such as chlorine, chlorine dioxide, or ozone; and


(5) For systems using ground water, compliance with the requirements of an EPA-approved State Wellhead Protection Program developed and implemented under section 1428 of the SDWA.


(f) The Administrator, pursuant to section 1412 of the Act, hereby identifies the technology, treatment techniques, or other means available identified in paragraph (e) of this section as affordable technology, treatment techniques, or other means available to systems serving 10,000 or fewer people for achieving compliance with the maximum contaminant level for total coliforms in paragraphs (a) and (b) of this section and for achieving compliance with the maximum contaminant level for E. coli in paragraph (c) of this section.


[78 FR 10347, Feb. 13, 2013]


§ 141.64 Maximum contaminant levels for disinfection byproducts.

(a) Bromate and chlorite. The maximum contaminant levels (MCLs) for bromate and chlorite are as follows:


Disinfection byproduct
MCL (mg/L)
Bromate0.010
Chlorite1.0

(1) Compliance dates for CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this paragraph (a) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (a) beginning January 1, 2004.


(2) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for bromate and chlorite identified in this paragraph (a):


Disinfection byproduct
Best available technology
BromateControl of ozone treatment process to reduce production of bromate
ChloriteControl of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels

(b) TTHM and HAA5. (1) Subpart L—RAA compliance. (i) Compliance dates. Subpart H systems serving 10,000 or more persons must comply with this paragraph (b)(1) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (b)(1) beginning January 1, 2004. All systems must comply with these MCLs until the date specified for subpart V compliance in § 141.620(c).


Disinfection byproduct
MCL (mg/L)
Total trihalomethanes (TTHM)0.080
Haloacetic acids (five) (HAA5)0.060

(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(1):


Disinfection byproduct
Best available technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant

(2) Subpart V—LRAA compliance. (i) Compliance dates. The subpart V MCLs for TTHM and HAA5 must be complied with as a locational running annual average at each monitoring location beginning the date specified for subpart V compliance in § 141.620(c).


Disinfection byproduct
MCL (mg/L)
Total trihalomethanes (TTHM)0.080
Haloacetic acids (five) (HAA5)0.060

(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for all systems that disinfect their source water:


Disinfection byproduct
Best available technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)Enhanced coagulation or enhanced softening, plus GAC10; or nanofiltration with a molecular weight cutoff ≤1000 Daltons; or GAC20

(iii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive:


Disinfection byproduct
Best available technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)Systems serving ≥10,000: Improved distribution system and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance
Systems serving

[71 FR 478, Jan. 4, 2006]


§ 141.65 Maximum residual disinfectant levels.

(a) Maximum residual disinfectant levels (MRDLs) are as follows:


Disinfectant residual
MRDL (mg/L)
Chlorine4.0 (as Cl2).
Chloramines4.0 (as Cl2).
Chlorine dioxide0.8 (as ClO2).

(b) Compliance dates—(1) CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this section beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this subpart beginning January 1, 2004.


(2) Transient NCWSs. Subpart H systems serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and using chlorine dioxide as a disinfectant or oxidant and systems using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2004.


(c) The Administrator, pursuant to Section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum residual disinfectant levels identified in paragraph (a) of this section: control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels.


[63 FR 69465, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]


§ 141.66 Maximum contaminant levels for radionuclides.

(a) [Reserved]


(b) MCL for combined radium-226 and -228. The maximum contaminant level for combined radium-226 and radium-228 is 5 pCi/L. The combined radium-226 and radium-228 value is determined by the addition of the results of the analysis for radium-226 and the analysis for radium-228.


(c) MCL for gross alpha particle activity (excluding radon and uranium). The maximum contaminant level for gross alpha particle activity (including radium-226 but excluding radon and uranium) is 15 pCi/L.


(d) MCL for beta particle and photon radioactivity. (1) The average annual concentration of beta particle and photon radioactivity from man-made radionuclides in drinking water must not produce an annual dose equivalent to the total body or any internal organ greater than 4 millirem/year (mrem/year).


(2) Except for the radionuclides listed in table A, the concentration of man-made radionuclides causing 4 mrem total body or organ dose equivalents must be calculated on the basis of 2 liter per day drinking water intake using the 168 hour data list in “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure,” NBS (National Bureau of Standards) Handbook 69 as amended August 1963, U.S. Department of Commerce. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of this document are available from the National Technical Information Service, NTIS ADA 280 282, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. The toll-free number is 800-553-6847. Copies may be inspected at EPA’s Drinking Water Docket, 401 M Street, SW., Washington, DC 20460; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. If two or more radionuclides are present, the sum of their annual dose equivalent to the total body or to any organ shall not exceed 4 mrem/year.


Table A—Average Annual Concentrations Assumed To Produce: a Total Body or Organ Dose of 4 mrem/yr

1. RadionuclideCritical organpCi per liter
2. TritiumTotal body20,000
3. Strontium-90Bone Marrow8

(e) MCL for uranium. The maximum contaminant level for uranium is 30 µg/L.


(f) Compliance dates. (1) Compliance dates for combined radium-226 and -228, gross alpha particle activity, gross beta particle and photon radioactivity, and uranium: Community water systems must comply with the MCLs listed in paragraphs (b), (c), (d), and (e) of this section beginning December 8, 2003 and compliance shall be determined in accordance with the requirements of §§ 141.25 and 141.26. Compliance with reporting requirements for the radionuclides under appendix A to subpart O and appendices A and B to subpart Q is required on December 8, 2003.


(2) [Reserved]


(g) Best available technologies (BATs) for radionuclides. The Administrator, pursuant to section 1412 of the Act, hereby identifies as indicated in the following table the best technology available for achieving compliance with the maximum contaminant levels for combined radium-226 and -228, uranium, gross alpha particle activity, and beta particle and photon radioactivity.


Table B—BAT for Combined Radium-226 and Radium-228, Uranium, Gross Alpha Particle Activity, and Beta Particle and Photon Radioactivity

Contaminant
BAT
1. Combined radium-226 and radium-228Ion exchange, reverse osmosis, lime softening.
2. UraniumIon exchange, reverse osmosis, lime softening, coagulation/filtration.
3. Gross alpha particle activity (excluding Radon and Uranium)Reverse osmosis.
4. Beta particle and photon radioactivityIon exchange, reverse osmosis.

(h) Small systems compliance technologies list for radionuclides.


Table C—List of Small Systems Compliance Technologies for Radionuclides and Limitations to Use

Unit technologies
Limitations (see footnotes)
Operator skill level required
1
Raw water quality range and

considerations.
1
1. Ion exchange (IE)(
a)		IntermediateAll ground waters.
2. Point of use (POU
2) IE		(
b)		BasicAll ground waters.
3. Reverse osmosis (RO)(
c)		AdvancedSurface waters usually require pre-filtration.
4. POU
2 RO		(
b)		BasicSurface waters usually require pre-filtration.
5. Lime softening(
d)		AdvancedAll waters.
6. Green sand filtration(
e)		Basic.
7. Co-precipitation with Barium sulfate(
f)		Intermediate to AdvancedGround waters with suitable water quality.
8. Electrodialysis/electrodialysis reversalBasic to IntermediateAll ground waters.
9. Pre-formed hydrous Manganese oxide filtration(
g)		IntermediateAll ground waters.
10. Activated alumina(
a), (
h)		AdvancedAll ground waters; competing anion concentrations may affect regeneration frequency.
11. Enhanced coagulation/filtration(
i)		AdvancedCan treat a wide range of water qualities.


1 National Research Council (NRC). Safe Water from Every Tap: Improving Water Service to Small Communities. National Academy Press. Washington, D.C. 1997.


2 A POU, or “point-of-use” technology is a treatment device installed at a single tap used for the purpose of reducing contaminants in drinking water at that one tap. POU devices are typically installed at the kitchen tap. See the April 21, 2000 NODA for more details.

Limitations Footnotes: Technologies for Radionuclides:


a The regeneration solution contains high concentrations of the contaminant ions. Disposal options should be carefully considered before choosing this technology.


b When POU devices are used for compliance, programs for long-term operation, maintenance, and monitoring must be provided by water utility to ensure proper performance.


c Reject water disposal options should be carefully considered before choosing this technology. See other RO limitations described in the SWTR Compliance Technologies Table.


d The combination of variable source water quality and the complexity of the water chemistry involved may make this technology too complex for small surface water systems.


e Removal efficiencies can vary depending on water quality.


f This technology may be very limited in application to small systems. Since the process requires static mixing, detention basins, and filtration, it is most applicable to systems with sufficiently high sulfate levels that already have a suitable filtration treatment train in place.


g This technology is most applicable to small systems that already have filtration in place.


h Handling of chemicals required during regeneration and pH adjustment may be too difficult for small systems without an adequately trained operator.


i Assumes modification to a coagulation/filtration process already in place.


Table D—Compliance Technologies by System Size Category for Radionuclide NPDWR’s

Contaminant
Compliance technologies
1 for system size categories (population served)
3,300-10,000
25-500
501-3,300
1. Combined radium-226 and radium-2281, 2, 3, 4, 5, 6, 7, 8, 91, 2, 3, 4, 5, 6, 7, 8, 91, 2, 3, 4, 5, 6, 7. 8, 9.
2. Gross alpha particle activity3, 43, 43, 4.
3. Beta particle activity and photon activity1, 2, 3, 41, 2, 3, 41, 2, 3, 4.
4. Uranium1, 2, 4, 10, 111, 2, 3, 4, 5, 10, 111, 2, 3, 4, 5, 10, 11.

Note:
1 Numbers correspond to those technologies found listed in the table C of 141.66(h).


[65 FR 76748, Dec. 7, 2000]


Subpart H—Filtration and Disinfection


Source:54 FR 27527, June 29, 1989, unless otherwise noted.

§ 141.70 General requirements.

(a) The requirements of this subpart H constitute national primary drinking water regulations. These regulations establish criteria under which filtration is required as a treatment technique for public water systems supplied by a surface water source and public water systems supplied by a ground water source under the direct influence of surface water. In addition, these regulations establish treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, and turbidity. Each public water system with a surface water source or a ground water source under the direct influence of surface water must provide treatment of that source water that complies with these treatment technique requirements. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:


(1) At least 99.9 percent (3-log) removal and/or inactivation of Giardia lamblia cysts between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer; and


(2) At least 99.99 percent (4-log) removal and/or inactivation of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer.


(b) A public water system using a surface water source or a ground water source under the direct influence of surface water is considered to be in compliance with the requirements of paragraph (a) of this section if:


(1) It meets the requirements for avoiding filtration in § 141.71 and the disinfection requirements in § 141.72(a); or


(2) It meets the filtration requirements in § 141.73 and the disinfection requirements in § 141.72(b).


(c) Each public water system using a surface water source or a ground water source under the direct influence of surface water must be operated by qualified personnel who meet the requirements specified by the State.


(d) Additional requirements for systems serving at least 10,000 people. In addition to complying with requirements in this subpart, systems serving at least 10,000 people must also comply with the requirements in subpart P of this part.


(e) Additional requirements for systems serving fewer than 10,000 people. In addition to complying with requirements in this subpart, systems serving fewer than 10,000 people must also comply with the requirements in subpart T of this part.


[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 67 FR 1836, Jan. 14, 2002]


§ 141.71 Criteria for avoiding filtration.

A public water system that uses a surface water source must meet all of the conditions of paragraphs (a) and (b) of this section, and is subject to paragraph (c) of this section, beginning December 30, 1991, unless the State has determined, in writing pursuant to § 1412(b)(7)(C)(iii), that filtration is required. A public water system that uses a ground water source under the direct influence of surface water must meet all of the conditions of paragraphs (a) and (b) of this section and is subject to paragraph (c) of this section, beginning 18 months after the State determines that it is under the direct influence of surface water, or December 30, 1991, whichever is later, unless the State has determined, in writing pursuant to § 1412(b)(7)(C)(iii), that filtration is required. If the State determines in writing pursuant to § 1412(b)(7)(C)(iii) before December 30, 1991, that filtration is required, the system must have installed filtration and meet the criteria for filtered systems specified in §§ 141.72(b) and 141.73 by June 29, 1993. Within 18 months of the failure of a system using surface water or a ground water source under the direct influence of surface water to meet any one of the requirements of paragraphs (a) and (b) of this section or after June 29, 1993, whichever is later, the system must have installed filtration and meet the criteria for filtered systems specified in §§ 141.72(b) and 141.73.


(a) Source water quality conditions. (1) The fecal coliform concentration must be equal to or less than 20/100 ml, or the total coliform concentration must be equal to or less than 100/100 ml (measured as specified in § 141.74 (a) (1) and (2) and (b)(1)), in representative samples of the source water immediately prior to the first or only point of disinfectant application in at least 90 percent of the measurements made for the 6 previous months that the system served water to the public on an ongoing basis. If a system measures both fecal and total coliforms, the fecal coliform criterion, but not the total coliform criterion, in this paragraph must be met.


(2) The turbidity level cannot exceed 5 NTU (measured as specified in § 141.74 (a)(1) and (b)(2)) in representative samples of the source water immediately prior to the first or only point of disinfectant application unless: (i) the State determines that any such event was caused by circumstances that were unusual and unpredictable; and (ii) as a result of any such event, there have not been more than two events in the past 12 months the system served water to the public, or more than five events in the past 120 months the system served water to the public, in which the turbidity level exceeded 5 NTU. An “event” is a series of consecutive days during which at least one turbidity measurement each day exceeds 5 NTU.


(b) Site-specific conditions. (1)(i) The public water system must meet the requirements of § 141.72(a)(1) at least 11 of the 12 previous months that the system served water to the public, on an ongoing basis, unless the system fails to meet the requirements during 2 of the 12 previous months that the system served water to the public, and the State determines that at least one of these failures was caused by circumstances that were unusual and unpredictable.


(ii) The public water system must meet the requirements of § 141.72(a)(2) at all times the system serves water to the public.


(iii) The public water system must meet the requirements of § 141.72(a)(3) at all times the system serves water to the public unless the State determines that any such failure was caused by circumstances that were unusual and unpredictable.


(iv) The public water system must meet the requirements of § 141.72(a)(4) on an ongoing basis unless the State determines that failure to meet these requirements was not caused by a deficiency in treatment of the source water.


(2) The public water system must maintain a watershed control program which minimizes the potential for contamination by Giardia lamblia cysts and viruses in the source water. The State must determine whether the watershed control program is adequate to meet this goal. The adequacy of a program to limit potential contamination by Giardia lamblia cysts and viruses must be based on: the comprehensiveness of the watershed review; the effectiveness of the system’s program to monitor and control detrimental activities occurring in the watershed; and the extent to which the water system has maximized land ownership and/or controlled land use within the watershed. At a minimum, the watershed control program must:


(i) Characterize the watershed hydrology and land ownership;


(ii) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and


(iii) Monitor the occurrence of activities which may have an adverse effect on source water quality.


The public water system must demonstrate through ownership and/or written agreements with landowners within the watershed that it can control all human activities which may have an adverse impact on the microbiological quality of the source water. The public water system must submit an annual report to the State that identifies any special concerns about the watershed and how they are being handled; describes activities in the watershed that affect water quality; and projects what adverse activities are expected to occur in the future and describes how the public water system expects to address them. For systems using a ground water source under the direct influence of surface water, an approved wellhead protection program developed under section 1428 of the Safe Drinking Water Act may be used, if the State deems it appropriate, to meet these requirements.

(3) The public water system must be subject to an annual on-site inspection to assess the watershed control program and disinfection treatment process. Either the State or a party approved by the State must conduct the on-site inspection. The inspection must be conducted by competent individuals such as sanitary and civil engineers, sanitarians, or technicians who have experience and knowledge about the operation and maintenance of a public water system, and who have a sound understanding of public health principles and waterborne diseases. A report of the on-site inspection summarizing all findings must be prepared every year. The on-site inspection must indicate to the State’s satisfaction that the watershed control program and disinfection treatment process are adequately designed and maintained. The on-site inspection must include:


(i) A review of the effectiveness of the watershed control program;


(ii) A review of the physical condition of the source intake and how well it is protected;


(iii) A review of the system’s equipment maintenance program to ensure there is low probability for failure of the disinfection process;


(iv) An inspection of the disinfection equipment for physical deterioration;


(v) A review of operating procedures;


(vi) A review of data records to ensure that all required tests are being conducted and recorded and disinfection is effectively practiced; and


(vii) Identification of any improvements which are needed in the equipment, system maintenance and operation, or data collection.


(4) The public water system must not have been identified as a source of a waterborne disease outbreak, or if it has been so identified, the system must have been modified sufficiently to prevent another such occurrence, as determined by the State.


(5) The public water system must comply with the maximum contaminant level (MCL) for total coliforms in § 141.63(a) and (b) and the MCL for E. coli in § 141.63(c) at least 11 months of the 12 previous months that the system served water to the public, on an ongoing basis, unless the State determines that failure to meet this requirement was not caused by a deficiency in treatment of the source water.


(6) The public water system must comply with the requirements for trihalomethanes in §§ 141.12 and 141.30 until December 31, 2001. After December 31, 2001, the system must comply with the requirements for total trihalomethanes, haloacetic acids (five), bromate, chlorite, chlorine, chloramines, and chlorine dioxide in subpart L of this part.


(c) Treatment technique violations. (1) A system that (i) fails to meet any one of the criteria in paragraphs (a) and (b) of this section and/or which the State has determined that filtration is required, in writing pursuant to § 1412(b)(7)(C)(iii), and (ii) fails to install filtration by the date specified in the introductory paragraph of this section is in violation of a treatment technique requirement.


(2) A system that has not installed filtration is in violation of a treatment technique requirement if:


(i) The turbidity level (measured as specified in § 141.74(a)(1) and (b)(2)) in a representative sample of the source water immediately prior to the first or only point of disinfection application exceeds 5 NTU; or


(ii) The system is identified as a source of a waterborne disease outbreak.


[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 66 FR 3776, Jan. 16, 2001; 69 FR 38855, June 29, 2004; 78 FR 10347, Feb. 13, 2013]


§ 141.72 Disinfection.

A public water system that uses a surface water source and does not provide filtration treatment must provide the disinfection treatment specified in paragraph (a) of this section beginning December 30, 1991, unless the State determines that filtration is required in writing pursuant to § 1412 (b)(7)(C)(iii). A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment must provide disinfection treatment specified in paragraph (a) of this section beginning December 30, 1991, or 18 months after the State determines that the ground water source is under the influence of surface water, whichever is later, unless the State has determined that filtration is required in writing pursuant to § 1412(b)(7)(C)(iii). If the State has determined that filtration is required, the system must comply with any interim disinfection requirements the State deems necessary before filtration is installed. A system that uses a surface water source that provides filtration treatment must provide the disinfection treatment specified in paragraph (b) of this section beginning June 29, 1993, or beginning when filtration is installed, whichever is later. A system that uses a ground water source under the direct influence of surface water and provides filtration treatment must provide disinfection treatment as specified in paragraph (b) of this section by June 29, 1993, or beginning when filtration is installed, whichever is later. Failure to meet any requirement of this section after the applicable date specified in this introductory paragraph is a treatment technique violation.


(a) Disinfection requirements for public water systems that do not provide filtration. Each public water system that does not provide filtration treatment must provide disinfection treatment as follows:


(1) The disinfection treatment must be sufficient to ensure at least 99.9 percent (3-log) inactivation of Giardia lamblia cysts and 99.99 percent (4-log) inactivation of viruses, every day the system serves water to the public, except any one day each month. Each day a system serves water to the public, the public water system must calculate the CT value(s) from the system’s treatment parameters, using the procedure specified in § 141.74(b)(3), and determine whether this value(s) is sufficient to achieve the specified inactivation rates for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the system may demonstrate to the State, through the use of a State-approved protocol for on-site disinfection challenge studies or other information satisfactory to the State, that CT99.9 values other than those specified in tables 2.1 and 3.1 in § 141.74(b)(3) or other operational parameters are adequate to demonstrate that the system is achieving minimum inactivation rates required by paragraph (a)(1) of this section.


(2) The disinfection system must have either (i) redundant components, including an auxiliary power supply with automatic start-up and alarm to ensure that disinfectant application is maintained continuously while water is being delivered to the distribution system, or (ii) automatic shut-off of delivery of water to the distribution system whenever there is less than 0.2 mg/l of residual disinfectant concentration in the water. If the State determines that automatic shut-off would cause unreasonable risk to health or interfere with fire protection, the system must comply with paragraph (a)(2)(i) of this section.


(3) The residual disinfectant concentration in the water entering the distribution system, measured as specified in § 141.74 (a)(2) and (b)(5), cannot be less than 0.2 mg/l for more than 4 hours.


(4)(i) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in § 141.74 (a)(2) and (b)(6), cannot be undetectable in more than 5 percent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in § 141.74(a)(1), is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula cannot exceed 5 percent in one month, for any two consecutive months.





where:

a = number of instances where the residual disinfectant concentration is measured;

b = number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured;

c = number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;

d = number of instances where the residual disinfectant concentration is measured but not detected and where the HPC is >500/ml; and

e = number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml.

(ii) If the State determines, based on site-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions specified by § 141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (a)(4)(i) of this section do not apply to that system.


(b) Disinfection requirements for public water systems which provide filtration. Each public water system that provides filtration treatment must provide disinfection treatment as follows.


(1) The disinfection treatment must be sufficient to ensure that the total treatment processes of that system achieve at least 99.9 percent (3-log) inactivation and/or removal of Giardia lamblia cysts and at least 99.99 percent (4-log) inactivation and/or removal of viruses, as determined by the State.


(2) The residual disinfectant concentration in the water entering the distribution system, measured as specified in § 141.74 (a)(2) and (c)(2), cannot be less than 0.2 mg/l for more than 4 hours.


(3)(i) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in § 141.74 (a)(2) and (c)(3), cannot be undetectable in more than 5 percent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in § 141.74(a)(1), is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula cannot exceed 5 percent in one month, for any two consecutive months.





where:

a = number of instances where the residual disinfectant concentration is measured;

b = number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured;

c = number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;

d = number of instances where no residual disinfectant concentration is detected and where the HPC is >500/ml; and

e = number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml.

(ii) If the State determines, based on site-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions specified in § 141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (b)(3)(i) of this section do not apply.


[54 FR 27527, June 29, 1989, as amended at 69 FR 38855, June 29, 2004]


§ 141.73 Filtration.

A public water system that uses a surface water source or a ground water source under the direct influence of surface water, and does not meet all of the criteria in § 141.71 (a) and (b) for avoiding filtration, must provide treatment consisting of both disinfection, as specified in § 141.72(b), and filtration treatment which complies with the requirements of paragraph (a), (b), (c), (d), or (e) of this section by June 29, 1993, or within 18 months of the failure to meet any one of the criteria for avoiding filtration in § 141.71 (a) and (b), whichever is later. Failure to meet any requirement of this section after the date specified in this introductory paragraph is a treatment technique violation.


(a) Conventional filtration treatment or direct filtration. (1) For systems using conventional filtration or direct filtration, the turbidity level of representative samples of a system’s filtered water must be less than or equal to 0.5 NTU in at least 95 percent of the measurements taken each month, measured as specified in § 141.74 (a)(1) and (c)(1), except that if the State determines that the system is capable of achieving at least 99.9 percent removal and/or inactivation of Giardia lamblia cysts at some turbidity level higher than 0.5 NTU in at least 95 percent of the measurements taken each month, the State may substitute this higher turbidity limit for that system. However, in no case may the State approve a turbidity limit that allows more than 1 NTU in more than 5 percent of the samples taken each month, measured as specified in § 141.74 (a)(1) and (c)(1).


(2) The turbidity level of representative samples of a system’s filtered water must at no time exceed 5 NTU, measured as specified in § 141.74 (a)(1) and (c)(1).


(3) Beginning January 1, 2002, systems serving at least 10,000 people must meet the turbidity requirements in § 141.173(a).


(4) Beginning January 1, 2005, systems serving fewer than 10,000 people must meet the turbidity requirements in §§ 141.550 through 141.553.


(b) Slow sand filtration. (1) For systems using slow sand filtration, the turbidity level of representative samples of a system’s filtered water must be less than or equal to 1 NTU in at least 95 percent of the measurements taken each month, measured as specified in § 141.74 (a)(1) and (c)(1), except that if the State determines there is no significant interference with disinfection at a higher turbidity level, the State may substitute this higher turbidity limit for that system.


(2) The turbidity level of representative samples of a system’s filtered water must at no time exceed 5 NTU, measured as specified in § 141.74 (a)(1) and (c)(1).


(c) Diatomaceous earth filtration. (1) For systems using diatomaceous earth filtration, the turbidity level of representative samples of a system’s filtered water must be less than or equal to 1 NTU in at least 95 percent of the measurements taken each month, measured as specified in § 141.74 (a)(1) and (c)(1).


(2) The turbidity level of representative samples of a system’s filtered water must at no time exceed 5 NTU, measured as specified in § 141.74 (a)(1) and (c)(1).


(d) Other filtration technologies. A public water system may use a filtration technology not listed in paragraphs (a) through (c) of this section if it demonstrates to the State, using pilot plant studies or other means, that the alternative filtration technology, in combination with disinfection treatment that meets the requirements of § 141.72(b), consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts and 99.99 percent removal and/or inactivation of viruses. For a system that makes this demonstration, the requirements of paragraph (b) of this section apply. Beginning January 1, 2002, systems serving at least 10,000 people must meet the requirements for other filtration technologies in § 141.173(b). Beginning January 14, 2005, systems serving fewer than 10,000 people must meet the requirements for other filtration technologies in § 141.550 through 141.553.


[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 66 FR 3776, Jan. 16, 2001; 67 FR 1836, Jan. 14, 2002; 69 FR 38855, June 29, 2004]


§ 141.74 Analytical and monitoring requirements.

(a) Analytical requirements. Only the analytical method(s) specified in this paragraph, or otherwise approved by EPA, may be used to demonstrate compliance with §§ 141.71, 141.72 and 141.73. Measurements for pH, turbidity, temperature and residual disinfectant concentrations must be conducted by a person approved by the State. Measurement for total coliforms, fecal coliforms and HPC must be conducted by a laboratory certified by the State or EPA to do such analysis. Until laboratory certification criteria are developed for the analysis of fecal coliforms and HPC, any laboratory certified for total coliforms analysis by the State or EPA is deemed certified for fecal coliforms and HPC analysis. The following procedures shall be conducted in accordance with the publications listed in the following section. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the methods published in Standard Methods for the Examination of Water and Wastewater may be obtained from the American Public Health Association et al., 1015 Fifteenth Street, NW., Washington, DC 20005; copies of the Minimal Medium ONPG-MUG Method as set forth in the article “National Field Evaluation of a Defined Substrate Method for the Simultaneous Enumeration of Total Coliforms and Esherichia coli from Drinking Water: Comparison with the Standard Multiple Tube Fermentation Method” (Edberg et al.), Applied and Environmental Microbiology, Volume 54, pp. 1595-1601, June 1988 (as amended under Erratum, Applied and Environmental Microbiology, Volume 54, p. 3197, December, 1988), may be obtained from the American Water Works Association Research Foundation, 6666 West Quincy Avenue, Denver, Colorado, 80235; and copies of the Indigo Method as set forth in the article “Determination of Ozone in Water by the Indigo Method” (Bader and Hoigne), may be obtained from Ozone Science & Engineering, Pergamon Press Ltd., Fairview Park, Elmsford, New York 10523. Copies may be inspected at the U.S. Environmental Protection Agency, Room EB15, 401 M St., SW., Washington, DC 20460 or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.


(1) Public water systems must conduct analysis of pH and temperature in accordance with one of the methods listed at § 141.23(k)(1). Public water systems must conduct analysis of total coliforms, fecal coliforms, heterotrophic bacteria, and turbidity in accordance with one of the following analytical methods or one of the alternative methods listed in appendix A to subpart C of this part and by using analytical test procedures contained in Technical Notes on Drinking Water Methods, EPA-600/R-94-173, October 1994. This document is available from the National Service Center for Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 45242-0419 or http://www.epa.gov/nscep/.


Organism
Methodology
Citation
1
Total Coliform
2		Total Coliform Fermentation Technique
3 4 5		9221 A, B, C
Total Coliform Membrane Filter Technique
6		9222 A, B, C
ONPG-MUG Test
7		9223
Fecal Coliforms
2		Fecal Coliform Procedure
8		9221 E
Fecal Coliform Filter Procedure9222 D
Heterotrophic bacteria
2		Pour Plate Method9215 B
SimPlate
11
Turbidity
13		Nephelometric Method2130 B
Nephelometric Method180.1
9
Great Lakes InstrumentsMethod 2
10
Hach FilterTrak10133
12

The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1, 6, 7 and 9-12 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800-426-4791. Documents may be inspected at EPA’s Drinking Water Docket, 1301 Constitution Avenue, NW., EPA West, Room B102, Washington DC 20460 (Telephone: 202-566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.


1 Except where noted, all methods refer to Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998), American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. The cited methods published in any of these three editions may be used. In addition, the following online versions may also be used: 2130 B-01, 9215 B-00, 9221 A, B, C, E-99, 9222 A, B, C, D-97, and 9223 B-97. Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that may be used.


2 The time from sample collection to initiation of analysis may not exceed 8 hours. Systems must hold samples below 10 deg. C during transit.


3 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the system conducts at least 25 parallel tests between this medium and lauryl tryptose broth using the water normally tested, and this comparison demonstrates that the false-positive rate and false-negative rate for total coliform, using lactose broth, is less than 10 percent.


4 Media should cover inverted tubes at least one-half to two-thirds after the sample is added.


5 No requirement exists to run the completed phase on 10 percent of all total coliform-positive confirmed tubes.


6 MI agar also may be used. Preparation and use of MI agar is set forth in the article, “New medium for the simultaneous detection of total coliform and Escherichia coli in water” by Brenner, K.P., et. al., 1993, Appl. Environ. Microbiol. 59:3534-3544. Also available from the Office of Water Resource Center (RC-4100T), 1200 Pennsylvania Avenue, NW., Washington DC 20460, EPA/600/J-99/225. Verification of colonies is not required.


7 The ONPG-MUG Test is also known as the Autoanalysis Colilert System.


8 A-1 broth may be held up to 7 days in a tightly closed screw cap tube at 4 °C.


9 “Methods for the Determination of Inorganic Substances in Environmental Samples”, EPA/600/R-93/100, August 1993. Available at NTIS, PB94-121811.


10 GLI Method 2, “Turbidity,” November 2, 1992, Great Lakes Instruments, Inc., 8855 North 55th Street, Milwaukee, WI 53223.


11 A description of the SimPlate method, “IDEXX SimPlate TM HPC Test Method for Heterotrophs in Water,” November 2000, can be obtained from IDEXX Laboratories, Inc., 1 IDEXX Drive, Westbrook, ME 04092, telephone (800) 321-0207.


12 A description of the Hach FilterTrak Method 10133, “Determination of Turbidity by Laser Nephelometry,” January 2000, Revision 2.0, can be obtained from; Hach Co., P.O. Box 389, Loveland, CO 80539-0389, telephone: 800-227-4224.


13 Styrene divinyl benzene beads (e.g., AMCO-AEPA-1 or equivalent) and stabilized formazin (e.g., Hach StablCal
TM or equivalent) are acceptable substitutes for formazin.


(2) Public water systems must measure residual disinfectant concentrations with one of the analytical methods in the following table or one of the alternative methods listed in appendix A to subpart C of this part. If approved by the State, residual disinfectant concentrations for free chlorine and combined chlorine also may be measured by using DPD colorimetric test kits. In addition States may approve the use of the ITS free chlorine test strip for the determination of free chlorine. Use of the test strips is described in Method D99-003, “Free Chlorine Species (HOCl− and OCl−) by Test Strip,” Revision 3.0, November 21, 2003, available from Industrial Test Systems, Inc., 1875 Langston St., Rock Hill, SC 29730. Free and total chlorine residuals may be measured continuously by adapting a specified chlorine residual method for use with a continuous monitoring instrument provided the chemistry, accuracy, and precision remain the same. Instruments used for continuous monitoring must be calibrated with a grab sample measurement at least every five days, or with a protocol approved by the State.


Residual
Methodology
SM
1
SM Online
2
Other
Free ChlorineAmperometric Titration4500-Cl D4500-Cl D-00D1253-03
3
DPD Ferrous Titrimetric4500-Cl F4500-Cl F-00
DPD Colorimetric4500-Cl G4500-Cl G-00
Syringaldazine (FACTS)4500-Cl H4500-Cl H-00
Total ChlorineAmperometric Titration4500-Cl D4500-Cl D-00D1253-03
3
Amperometric Titration (low level measurement)4500-Cl E4500-Cl E-00
DPD Ferrous Titrimetric4500-Cl F4500-Cl F-00
DPD Colorimetric4500-Cl G4500-Cl G-00
Iodometric Electrode4500-Cl I4500-Cl I-00
Chlorine DioxideAmperometric Titration4500-ClO2 C4500-ClO2 C-00
DPD Method4500-ClO2 D
Amperometric Titration4500-ClO2 E4500-ClO2 E-00
Spectrophotometric327.0, Revision 1.1
4
OzoneIndigo Method4500-O3 B4500-O3 B-97


1 All the listed methods are contained in the 18th, 19th, and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1992, 1995, and 1998; the cited methods published in any of these three editions may be used.


2 Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that may be used.


3 Annual Book of ASTM Standards, Vol. 11.01, 2004 ; ASTM International; any year containing the cited version of the method may be used. Copies of this method may be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700 West Conshohocken, PA 19428-2959.


4 EPA Method 327.0, Revision 1.1, “Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidase with Detection by Visible Spectrophotometry,” USEPA, May 2005, EPA 815-R-05-008. Available online at http://www.epa.gov/safewater/methods/sourcalt.html.


(b) Monitoring requirements for systems that do not provide filtration. A public water system that uses a surface water source and does not provide filtration treatment must begin monitoring, as specified in this paragraph (b), beginning December 31, 1990, unless the State has determined that filtration is required in writing pursuant to § 1412(b)(7)(C)(iii), in which case the State may specify alternative monitoring requirements, as appropriate, until filtration is in place. A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment must begin monitoring as specified in this paragraph (b) beginning December 31, 1990, or 6 months after the State determines that the ground water source is under the direct influence of surface water, whichever is later, unless the State has determined that filtration is required in writing pursuant to § 1412(b)(7)(C)(iii), in which case the State may specify alternative monitoring requirements, as appropriate, until filtration is in place.


(1) Fecal coliform or total coliform density measurements as required by § 141.71(a)(1) must be performed on representative source water samples immediately prior to the first or only point of disinfectant application. The system must sample for fecal or total coliforms at the following minimum frequency each week the system serves water to the public:


System size (persons served)
Samples/week
1
≤5001
501 to 3,3002
3,301 to 10,0003
10,001 to 25,0004
>25,0005


1 Must be taken on separate days.


Also, one fecal or total coliform density measurement must be made every day the system serves water to the public and the turbidity of the source water exceeds 1 NTU (these samples count towards the weekly coliform sampling requirement) unless the State determines that the system, for logistical reasons outside the system’s control, cannot have the sample analyzed within 30 hours of collection.

(2) Turbidity measurements as required by § 141.71(a)(2) must be performed on representative grab samples of source water immediately prior to the first or only point of disinfectant application every four hours (or more frequently) that the system serves water to the public. A public water system may substitute continuous turbidity monitoring for grab sample monitoring if it validates the continuous measurement for accuracy on a regular basis using a protocol approved by the State.


(3) The total inactivation ratio for each day that the system is in operation must be determined based on the CT99.9 values in tables 1.1-1.6, 2.1, and 3.1 of this section, as appropriate. The parameters necessary to determine the total inactivation ratio must be monitored as follows:


(i) The temperature of the disinfected water must be measured at least once per day at each residual disinfectant concentration sampling point.


(ii) If the system uses chlorine, the pH of the disinfected water must be measured at least once per day at each chlorine residual disinfectant concentration sampling point.


(iii) The disinfectant contact time(s) (“T”) must be determined for each day during peak hourly flow.


(iv) The residual disinfectant concentration(s) (“C”) of the water before or at the first customer must be measured each day during peak hourly flow.


(v) If a system uses a disinfectant other than chlorine, the system may demonstrate to the State, through the use of a State-approved protocol for on-site disinfection challenge studies or other information satisfactory to the State, that CT99.9 values other than those specified in tables 2.1 and 3.1 in this section other operational parameters are adequate to demonstrate that the system is achieving the minimum inactivation rates required by § 141.72(a)(1).


Table 1.1—CT Values (CT99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 0.5 °C or Lower
1

Residual (mg/l)
pH
≤6.0
6.5
7.0
7.5
8.0
8.5
≤9.0
≤0.4137163195237277329390
0.6141168200239286342407
0.8145172205246295354422
1.0148176210253304365437
1.2152180215259313376451
1.4155184221266321387464
1.6157189226273329397477
1.8162193231279338407489
2.0165197236286346417500
2.2169201242297353426511
2.4172205247298361435522
2.6175209252304368444533
2.8178213257310375452543
3.0181217261316382460552


1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linear interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.


Table 1.2—CT Values (CT 99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 5.0 °C
1

Free residual (mg/l)
pH
≤6.0
6.5
7.0
7.5
8.0
8.5
≤9.0
≤0.497117139166198236279
0.6100120143171204244291
0.8103122146175210252301
1.0105125149179216260312
1.2107127152183221267320
1.4109130155187227274329
1.6111132158192232281337
1.8114135162196238287345
2.0116138165200243294353
2.2118140169204248300361
2.4120143172209253306368
2.6122146175213258312375
2.8124148178217263318382
3.0126151182221268324389


1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linear interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature, and at the higher pH.


Table 1.3—CT Values (CT 99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 10.0 °C
1

Free residual (mg/l)
pH
≤6.0
6.5
7.0
7.5
8.0
8.5
≤9.0
≤0.47388104125149177209
0.67590107128153183218
0.87892110131158189226
1.07994112134162195234
1.28095114137166200240
1.48298116140170206247
1.68399119144174211253
1.886101122147179215259
2.087104124150182221265
2.289105127153186225271
2.490107129157190230276
2.692110131160194234281
2.893111134163197239287
3.095113137166201243292


1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linear interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature, and at the higher pH.


Table 1.4—CT Values (CT 99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 15.0 °C
1

Free residual (mg/l)
pH
≤6.0
6.5
7.0
7.5
8.0
8.5
≤9.0
≤0.44959708399118140
0.650607286102122146
0.852617388105126151
1.053637590108130156
1.254647692111134160
1.455657894114137165
1.656667996116141169
1.857688198119144173
2.0586983100122147177
2.2597085102124150181
2.4607286105127153184
2.6617388107129156188
2.8627489109132159191
3.0637691111134162195


1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linear interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature, and at the higher pH.


Table 1.5—CT Values (CT99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 20 °C
1

Free residual (mg/l)
pH
≤6.0
6.5
7.0
7.5
8.0
8.5
≤9.0
≤0.4364452627489105
0.6384554647792109
0.8394655667995113
1.0394756678198117
1.24048576983100120
1.44149587085103123
1.64250597287105126
1.84351617489108129
2.04452627591110132
2.24453637793113135
2.44554657895115138
2.64655668097117141
2.84756678199119143
3.047576883101122146


1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linear interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature, and at the higher pH.


Table 1.6—CT Values (CT99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 25 °C
1 and Higher

Free residual (mg/l)
pH
≤6.0
6.5
7.0
7.5
8.0
8.5
≤9.0
≤0.424293542505970
0.625303643516173
0.826313744536375
1.026313745546578
1.227323846556780
1.427333947576982
1.628334048587084
1.829344149607286
2.029354150617488
2.230354251627590
2.430364352637792
2.631374453657894
2.831374554668096
3.032384655678197


1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linear interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature, and at the higher pH.


Table 2.1—CT Values (CT99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Chlorine Dioxide and Ozone
1


Temperature
5 °C
10 °C
15 °C
20 °C
≥25 °C
Chlorine dioxide632623191511
Ozone2.91.91.40.950.720.48


1 These CT values achieve greater than 99.99 percent inactivation of viruses. CT values between the indicated temperatures may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature for determining CT99.9 values between indicated temperatures.


Table 3.1—CT Values (CT 99.9) for 99.9 Percent Inactivation of Giardia Lamblia Cysts By Chloramines
1

Temperature
5 °C
10 °C
15 °C
20 °C
25 °C
3,8002,2001,8501,5001,100750


1 These values are for pH values of 6 to 9. These CT values may be assumed to achieve greater than 99.99 percent inactivation of viruses only if chlorine is added and mixed in the water prior to the addition of ammonia. If this condition is not met, the system must demonstrate, based on on-site studies or other information, as approved by the State, that the system is achieving at least 99.99 percent inactivation of viruses. CT values between the indicated temperatures may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature for determining CT99.9 values between indicated temperatures.


(4) The total inactivation ratio must be calculated as follows:


(i) If the system uses only one point of disinfectant application, the system may determine the total inactivation ratio based on either of the following two methods:


(A) One inactivation ratio (CTcalc/CT99.9) is determined before or at the first customer during peak hourly flow and if the CTcalc/CT99.9 ≥1.0, the 99.9 percent Giardia lamblia inactivation requirement has been achieved; or


(B) Successive CTcalc/CT99.9 values, representing sequential inactivation ratios, are determined between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternative, the following method must be used to calculate the total inactivation ratio:




lamblia inactivation requirement has been achieved.

(ii) If the system uses more than one point of disinfectant application before or at the first customer, the system must determine the CT value of each disinfection sequence immediately prior to the next point of disinfectant application during peak hourly flow. The CTcalc/CT99.9 value of each sequence and




must be calculated using the method in paragraph (b)(4)(i)(B) of this section to determine if the system is in compliance with § 141.72(a).

(iii) Although not required, the total percent inactivation for a system with one or more points of residual disinfectant concentration monitoring may be calculated by solving the following equation:




(5) The residual disinfectant concentration of the water entering the distribution system must be monitored continuously, and the lowest value must be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab sampling every 4 hours may be conducted in lieu of continuous monitoring, but for no more than 5 working days following the failure of the equipment, and systems serving 3,300 or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies prescribed below:


System size by population
Samples/day
1
1
501 to 1,0002
1,001 to 2,5003
2,501 to 3,3004


1 The day’s samples cannot be taken at the same time. The sampling intervals are subject to State review and approval.


If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the system must take a grab sample every 4 hours until the residual concentration is equal to or greater than 0.2 mg/l.

(6)(i) Until March 31, 2016, the residual disinfectant concentration must be measured at least at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in § 141.21. Beginning April 1, 2016, the residual disinfectant concentration must be measured at least at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in §§ 141.854 through 141.858. The State may allow a public water system which uses both a surface water source or a ground water source under direct influence of surface water, and a ground water source, to take disinfectant residual samples at points other than the total coliform sampling points if the State determines that such points are more representative of treated (disinfected) water quality within the distribution system. Heterotrophic bacteria, measured as heterotrophic plate count (HPC) as specified in paragraph (a)(1) of this section, may be measured in lieu of residual disinfectant concentration.


(ii) If the State determines, based on site-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions specified by paragraph (a)(1) of this section and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (b)(6)(i) of this section do not apply to that system.


(c) Monitoring requirements for systems using filtration treatment. A public water system that uses a surface water source or a ground water source under the influence of surface water and provides filtration treatment must monitor in accordance with this paragraph (c) beginning June 29, 1993, or when filtration is installed, whichever is later.


(1) Turbidity measurements as required by § 141.73 must be performed on representative samples of the system’s filtered water every four hours (or more frequently) that the system serves water to the public. A public water system may substitute continuous turbidity monitoring for grab sample monitoring if it validates the continuous measurement for accuracy on a regular basis using a protocol approved by the State. For any systems using slow sand filtration or filtration treatment other than conventional treatment, direct filtration, or diatomaceous earth filtration, the State may reduce the sampling frequency to once per day if it determines that less frequent monitoring is sufficient to indicate effective filtration performance. For systems serving 500 or fewer persons, the State may reduce the turbidity sampling frequency to once per day, regardless of the type of filtration treatment used, if the State determines that less frequent monitoring is sufficient to indicate effective filtration performance.


(2) The residual disinfectant concentration of the water entering the distribution system must be monitored continuously, and the lowest value must be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab sampling every 4 hours may be conducted in lieu of continuous monitoring, but for no more than 5 working days following the failure of the equipment, and systems serving 3,300 or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies each day prescribed below:


System size by population
Samples/day
1
±5001
501 to 1,0002
1,001 to 2,5003
2,501 to 3,3004


1 The day’s samples cannot be taken at the same time. The sampling intervals are subject to State review and approval.


If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the system must take a grab sample every 4 hours until the residual disinfectant concentration is equal to or greater than 0.2 mg/l.

(3)(i) Until March 31, 2016, the residual disinfectant concentration must be measured at least at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in § 141.21. Beginning April 1, 2016, the residual disinfectant concentration must be measured at least at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in §§ 141.854 through 141.858. The State may allow a public water system which uses both a surface water source or a ground water source under direct influence of surface water, and a ground water source, to take disinfectant residual samples at points other than the total coliform sampling points if the State determines that such points are more representative of treated (disinfected) water quality within the distribution system. Heterotrophic bacteria, measured as heterotrophic plate count (HPC) as specified in paragraph (a)(1) of this section, may be measured in lieu of residual disinfectant concentration.


(ii) If the State determines, based on site-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions specified by paragraph (a)(1) of this section and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (c)(3)(i) of this section do not apply to that system.


[54 FR 27527, June 29, 1989, as amended at 59 FR 62470, Dec. 5, 1994; 60 FR 34086, June 29, 1995; 64 FR 67465, Dec. 1, 1999; 67 FR 65252, Oct. 23, 2002; 67 FR 65901, Oct. 29, 2002; 69 FR 38856, June 29, 2004; 72 FR 11247, Mar. 12, 2007; 74 FR 30958, June 29, 2009; 78 FR 10347, Feb. 13, 2013]


§ 141.75 Reporting and recordkeeping requirements.

(a) A public water system that uses a surface water source and does not provide filtration treatment must report monthly to the State the information specified in this paragraph (a) beginning December 31, 1990, unless the State has determined that filtration is required in writing pursuant to section 1412(b)(7)(C)(iii), in which case the State may specify alternative reporting requirements, as appropriate, until filtration is in place. A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment must report monthly to the State the information specified in this paragraph (a) beginning December 31, 1990, or 6 months after the State determines that the ground water source is under the direct influence of surface water, whichever is later, unless the State has determined that filtration is required in writing pursuant to § 1412(b)(7)(C)(iii), in which case the State may specify alternative reporting requirements, as appropriate, until filtration is in place.


(1) Source water quality information must be reported to the State within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:


(i) The cumulative number of months for which results are reported.


(ii) The number of fecal and/or total coliform samples, whichever are analyzed during the month (if a system monitors for both, only fecal coliforms must be reported), the dates of sample collection, and the dates when the turbidity level exceeded 1 NTU.


(iii) The number of samples during the month that had equal to or less than 20/100 ml fecal coliforms and/or equal to or less than 100/100 ml total coliforms, whichever are analyzed.


(iv) The cumulative number of fecal or total coliform samples, whichever are analyzed, during the previous six months the system served water to the public.


(v) The cumulative number of samples that had equal to or less than 20/100 ml fecal coliforms or equal to or less than 100/100 ml total coliforms, whichever are analyzed, during the previous six months the system served water to the public.


(vi) The percentage of samples that had equal to or less than 20/100 ml fecal coliforms or equal to or less than 100/100 ml total coliforms, whichever are analyzed, during the previous six months the system served water to the public.


(vii) The maximum turbidity level measured during the month, the date(s) of occurrence for any measurement(s) which exceeded 5 NTU, and the date(s) the occurrence(s) was reported to the State.


(viii) For the first 12 months of recordkeeping, the dates and cumulative number of events during which the turbidity exceeded 5 NTU, and after one year of recordkeeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded 5 NTU in the previous 12 months the system served water to the public.


(ix) For the first 120 months of recordkeeping, the dates and cumulative number of events during which the turbidity exceeded 5 NTU, and after 10 years of recordkeeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded 5 NTU in the previous 120 months the system served water to the public.


(2) Disinfection information specified in § 141.74(b) must be reported to the State within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:


(i) For each day, the lowest measurement of residual disinfectant concentration in mg/l in water entering the distribution system.


(ii) The date and duration of each period when the residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l and when the State was notified of the occurrence.


(iii) The daily residual disinfectant concentration(s) (in mg/l) and disinfectant contact time(s) (in minutes) used for calculating the CT value(s).


(iv) If chlorine is used, the daily measurement(s) of pH of disinfected water following each point of chlorine disinfection.


(v) The daily measurement(s) of water temperature in °C following each point of disinfection.


(vi) The daily CTcalc and CTcalc/CT99.9 values for each disinfectant measurement or sequence and the sum of all CTcalc/CT99.9 values ((CTcalc/CT99.9)) before or at the first customer.


(vii) The daily determination of whether disinfection achieves adequate Giardia cyst and virus inactivation, i.e., whether (CTcalc/CT99.9) is at least 1.0 or, where disinfectants other than chlorine are used, other indicator conditions that the State determines are appropriate, are met.


(viii) The following information on the samples taken in the distribution system in conjunction with total coliform monitoring pursuant to § 141.72:


(A) Number of instances where the residual disinfectant concentration is measured;


(B) Number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured;


(C) Number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;


(D) Number of instances where the residual disinfectant concentration is detected and where HPC is >500/ml;


(E) Number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml;


(F) For the current and previous month the system served water to the public, the value of “V” in the following formula:





where:

a = the value in paragraph (a)(2)(viii)(A) of this section,

b = the value in paragraph (a)(2)(viii)(B) of this section,

c = the value in paragraph (a)(2)(viii)(C) of this section,

d = the value in paragraph (a)(2)(viii)(D) of this section, and

e = the value in paragraph (a)(2)(viii)(E) of this section.

(G) If the State determines, based on site-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions specified by § 141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (a)(2)(viii) (A)-(F) of this section do not apply to that system.


(ix) A system need not report the data listed in paragraphs (a)(2) (i), and (iii)-(vi) of this section if all data listed in paragraphs (a)(2) (i)-(viii) of this section remain on file at the system, and the State determines that:


(A) The system has submitted to the State all the information required by paragraphs (a)(2) (i)-(viii) of this section for at least 12 months; and


(B) The State has determined that the system is not required to provide filtration treatment.


(3) No later than ten days after the end of each Federal fiscal year (September 30), each system must provide to the State a report which summarizes its compliance with all watershed control program requirements specified in § 141.71(b)(2).


(4) No later than ten days after the end of each Federal fiscal year (September 30), each system must provide to the State a report on the on-site inspection conducted during that year pursuant to § 141.71(b)(3), unless the on-site inspection was conducted by the State. If the inspection was conducted by the State, the State must provide a copy of its report to the public water system.


(5)(i) Each system, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, must report that occurrence to the State as soon as possible, but no later than by the end of the next business day.


(ii) If at any time the turbidity exceeds 5 NTU, the system must consult with the primacy agency as soon as practical, but no later than 24 hours after the exceedance is known, in accordance with the public notification requirements under § 141.203(b)(3).


(iii) If at any time the residual falls below 0.2 mg/l in the water entering the distribution system, the system must notify the State as soon as possible, but no later than by the end of the next business day. The system also must notify the State by the end of the next business day whether or not the residual was restored to at least 0.2 mg/l within 4 hours.


(b) A public water system that uses a surface water source or a ground water source under the direct influence of surface water and provides filtration treatment must report monthly to the State the information specified in this paragraph (b) beginning June 29, 1993, or when filtration is installed, whichever is later.


(1) Turbidity measurements as required by § 141.74(c)(1) must be reported within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:


(i) The total number of filtered water turbidity measurements taken during the month.


(ii) The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to the turbidity limits specified in § 141.73 for the filtration technology being used.


(iii) The date and value of any turbidity measurements taken during the month which exceed 5 NTU.


(2) Disinfection information specified in § 141.74(c) must be reported to the State within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:


(i) For each day, the lowest measurement of residual disinfectant concentration in mg/l in water entering the distribution system.


(ii) The date and duration of each period when the residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l and when the State was notified of the occurrence.


(iii) The following information on the samples taken in the distribution system in conjunction with total coliform monitoring pursuant to § 141.72:


(A) Number of instances where the residual disinfectant concentration is measured;


(B) Number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured;


(C) Number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;


(D) Number of instances where no residual disinfectant concentration is detected and where HPC is >500/ml;


(E) Number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml;


(F) For the current and previous month the system serves water to the public, the value of “V” in the following formula:





where:

a = the value in paragraph (b)(2)(iii)(A) of this section,

b = the value in paragraph (b)(2)(iii)(B) of this section,

c = the value in paragraph (b)(2)(iii)(C) of this section,

d = the value in paragraph (b)(2)(iii)(D) of this section, and

e = the value in paragraph (b)(2)(iii)(E) of this section.

(G) If the State determines, based on site-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory within the requisite time and temperature conditions specified by § 141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (b)(2)(iii) (A)-(F) of this section do not apply.


(iv) A system need not report the data listed in paragraph (b)(2)(i) of this section if all data listed in paragraphs (b)(2) (i)-(iii) of this section remain on file at the system and the State determines that the system has submitted all the information required by paragraphs (b)(2) (i)-(iii) of this section for at least 12 months.


(3)(i) Each system, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, must report that occurrence to the State as soon as possible, but no later than by the end of the next business day.


(ii) If at any time the turbidity exceeds 5 NTU, the system must consult with the primacy agency as soon as practical, but no later than 24 hours after the exceedance is known, in accordance with the public notification requirements under § 141.203(b)(3).


(iii) If at any time the residual falls below 0.2 mg/l in the water entering the distribution system, the system must notify the State as soon as possible, but no later than by the end of the next business day. The system also must notify the State by the end of the next business day whether or not the residual was restored to at least 0.2 mg/l within 4 hours.


[54 FR 27527, June 29, 1989, as amended at 65 FR 26022, May 4, 2000; 69 FR 38856, June 29, 2004]


§ 141.76 Recycle provisions.

(a) Applicability. All subpart H systems that employ conventional filtration or direct filtration treatment and that recycle spent filter backwash water, thickener supernatant, or liquids from dewatering processes must meet the requirements in paragraphs (b) through (d) of this section.


(b) Reporting. A system must notify the State in writing by Decemeber 8, 2003, if the system recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes. This notification must include, at a minimum, the information specified in paragraphs (b)(1) and (2) of this section.


(1) A plant schematic showing the origin of all flows which are recycled (including, but not limited to, spent filter backwash water, thickener supernatant, and liquids from dewatering processes), the hydraulic conveyance used to transport them, and the location where they are re-introduced back into the treatment plant.


(2) Typical recycle flow in gallons per minute (gpm), the highest observed plant flow experienced in the previous year (gpm), design flow for the treatment plant (gpm), and State-approved operating capacity for the plant where the State has made such determinations.


(c) Treatment technique requirement. Any system that recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes must return these flows through the processes of a system’s existing conventional or direct filtration system as defined in § 141.2 or at an alternate location approved by the State by June 8, 2004. If capital improvements are required to modify the recycle location to meet this requirement, all capital improvements must be completed no later than June 8, 2006.


(d) Recordkeeping. The system must collect and retain on file recycle flow information specified in paragraphs (d)(1) through (6) of this section for review and evaluation by the State beginning June 8, 2004.


(1) Copy of the recycle notification and information submitted to the State under paragraph (b) of this section.


(2) List of all recycle flows and the frequency with which they are returned.


(3) Average and maximum backwash flow rate through the filters and the average and maximum duration of the filter backwash process in minutes.


(4) Typical filter run length and a written summary of how filter run length is determined.


(5) The type of treatment provided for the recycle flow.


(6) Data on the physical dimensions of the equalization and/or treatment units, typical and maximum hydraulic loading rates, type of treatment chemicals used and average dose and frequency of use, and frequency at which solids are removed, if applicable.


[66 FR 31103, June 8, 2001]


Subpart I—Control of Lead and Copper


Source:56 FR 26548, June 7, 1991, unless otherwise noted.

§ 141.80 General requirements.

(a) Applicability, effective date, and compliance deadlines. The requirements of this subpart constitute the national primary drinking water regulations for lead and copper.


(1) The provisions of this subpart apply to community water systems and non-transient, non-community water systems (in this subpart referred to as “water systems” or “systems”) as defined at § 141.2.


(2) The requirements of this subpart are effective as of December 16, 2021.


(3) Community water systems and non-transient, non-community water systems must comply with the requirements of this subpart no later than October 16, 2024, except where otherwise specified in §§ 141.81, 141.84, 141.85, 141.86, and 141.90, or where an exemption in accordance with 40 CFR part 142, subpart C or F, has been established by the Administrator.


(4)(i) Between December 16, 2021, and October 16, 2024, community water systems and non-transient, non-community water systems must comply with 40 CFR 141.80 through 141.91, as codified on July 1, 2020.


(ii) If an exemption from subpart I of this part has been issued in accordance with 40 CFR part 142, subpart C or F, prior to December 16, 2021, then the water systems must comply with 40 CFR 141.80 through 141.91, as codified on July 1, 2020, until the expiration of that exemption.


(b) Scope. The regulations in this subpart establish a treatment technique that includes requirements for corrosion control treatment, source water treatment, lead service line inventory, lead service line replacement, public notice, monitoring for lead in schools and child care facilities, and public education. Several of the requirements in this subpart are prompted by the lead and copper action levels or the lead trigger level, specified in paragraph (c) of this section, as measured in samples collected at consumers’ taps. The requirements for sampling for lead in schools and child care facilities and public education requirements in this subpart apply to all community water systems regardless of the results of the compliance tap sampling.


(c) Lead trigger level, lead action level, and copper action level. Trigger levels and action levels must be determined based on tap water samples collected in accordance with the tap sampling monitoring requirements of § 141.86 for the purpose of calculating the 90th percentile and tested using the analytical methods specified in § 141.89. The trigger level and action levels described in this paragraph (c) are applicable to all sections of subpart I of this part. Trigger level and action levels for lead and copper are as follows:


(1) The lead trigger level is exceeded if the 90th percentile concentration of lead as specified in paragraph (c)(4) of this section is greater than 10 µg/L.


(2) The lead action level is exceeded if the 90th percentile concentration of lead as specified in paragraph (c)(4) of this section is greater than 15 µg/L.


(3) The copper action level is exceeded if the 90th percentile concentration of copper as specified in paragraph (c)(4) of this section is greater than 1.3 mg/L.


(4) For purposes of this subpart, the 90th percentile concentration shall be computed as follows:


(i) For systems that do not have lead service line sites and only have sites identified as Tier 3, 4, or 5 under § 141.86(a).


(A) The results of all lead or copper samples taken during a tap sampling period shall be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Each sampling result shall be assigned a number, ascending by single integers beginning with the number 1 for the sample with the lowest contaminant level. The number assigned to the sample with the highest contaminant level shall be equal to the total number of samples taken.


(B) The number of samples taken during the tap sampling period shall be multiplied by 0.9.


(C) The contaminant concentration in the numbered sample yielded by the calculation in paragraph (c)(4)(i)(B) of this section is the 90th percentile concentration.


(D) For water systems serving fewer than 100 people that collect 5 samples per tap sampling period, the 90th percentile concentration is the average of the highest and second highest concentration.


(E) For a public water system that has been allowed by the State to collect fewer than five samples in accordance with § 141.86(c), or has failed to collect five samples, the sample result with the highest concentration is considered the 90th percentile value.


(ii) For public water systems with lead service lines with sites identified as Tier 1 or 2 under § 141.86(a) with enough Tier 1 or 2 sites to meet the minimum number of sites listed in § 141.86(c):


(A) The results of all lead or copper samples taken at Tier 1 or Tier 2 sites during a tap sampling period shall be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Sample results from Tier 3, 4, or 5 sites shall not be included in this calculation. Each sampling result shall be assigned a number, ascending by single integers beginning with the number 1 for the sample with the lowest contaminant level. The number assigned to the sample with the highest contaminant level shall be equal to the total number of samples taken.


(B) The number of samples taken at Tier 1 or Tier 2 sites during the tap sampling period shall be multiplied by 0.9.


(C) The contaminant concentration in the numbered sample yielded by the calculation in paragraph (c)(4)(ii)(B) of this section is the 90th percentile concentration.


(D) For water systems serving fewer than 100 people that collect 5 samples per tap sampling period, the 90th percentile concentration is the average of the highest and second highest concentration.


(E) For a public water system that has been allowed by the State to collect fewer than five samples in accordance with § 141.86(c), or has failed to collect five samples, the sample result with the highest concentration is considered the 90th percentile value.


(iii) For systems with lead service lines with sites identified as Tier 1 or 2 under § 141.86(a) with insufficient number of Tier 1 or 2 sites to meet the minimum number of sites listed in § 141.86(c):


(A) The results of all lead or copper samples taken at Tier 1 or Tier 2 sites along with the highest results from Tier 3, 4, or 5 sites sufficient to meet the minimum number of sites shall be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Sample results from any remaining Tier 3, 4, and 5 sites shall not be included in this calculation. Each sampling result shall be assigned a number, ascending by single integers beginning with the number 1 for the sample with the lowest contaminant level. The number assigned to the sample with the highest contaminant level shall be equal to the total minimum number of sites listed in § 141.86(c).


(B) The required minimum number of sites listed in § 141.86(c) shall be multiplied by 0.9.


(C) The contaminant concentration in the numbered sample yielded by the calculation in paragraph (c)(4)(iii)(B) is the 90th percentile concentration.


(D) For water systems serving fewer than 100 people that collect 5 samples per tap sampling period, the 90th percentile concentration is the average of the highest and second highest concentration.


(E) For a public water system that has been allowed by the State to collect fewer than five samples in accordance with § 141.86(c), or has failed to collect five samples, the sample result with the highest concentration is considered the 90th percentile value.


(d) Corrosion control requirements. (1) All water systems shall install and operate corrosion control treatment in accordance with §§ 141.81 and 141.82, and that meets the definition of optimal corrosion control treatment at § 141.2.


(2) Any water system that complies with the applicable corrosion control treatment requirements specified by the State under §§ 141.81 and 141.82 shall be deemed in compliance with the treatment requirement contained in paragraph (d)(1) of this section.


(3) Any small or non-transient non-community water system that complies with the applicable small system compliance flexibility requirements specified by the State under §§ 141.81(a)(3) and 141.93 is deemed to be in compliance with the treatment requirement in paragraph (d)(1) of this section.


(4) Any water system shall notify the State in writing pursuant to § 141.90(a)(3) of any upcoming long-term change in treatment or addition of a new source as described in § 141.90(a)(3). The State must review and approve the addition of a new source or long-term change in water treatment before it is implemented by the water system. The State may require any such water system to conduct additional monitoring or to take other action the State deems appropriate to ensure that such water system maintains minimal levels of corrosion control in its distribution system.


(e) Source water requirements. (1) Any system exceeding the lead or copper action level shall implement all applicable source water treatment requirements specified by the State under § 141.83.


(2) Any system that changes their source water or makes long-term treatment changes shall submit written documentation to the State describing the change in accordance with §§ 141.81(a)(3), 141.86(d)(2)(iv), and 141.90(a)(3). The State must review and approve the change before it is implemented by the water system.


(f) Lead service line replacements and inventory. Lead service line replacements must be conducted as follows:


(1) Any water system exceeding the lead action level specified at paragraph (c) of this section must complete mandatory lead service line replacement. Lead service line replacement must be conducted in accordance with § 141.84(g) and must include public education pursuant to § 141.85(a) and (b).


(2) Any water system exceeding the lead trigger level specified at paragraph (c) of this section must complete goal-based lead service line replacement pursuant to § 141.84(f) and public education pursuant to § 141.85(g) and (h).


(3) All water systems must prepare an inventory of service lines connected to its distribution system, whether or not they are owned or controlled by the water system, to identify those service lines that are made of lead or of unknown material. The inventory must be prepared in accordance with § 141.84(a).


(g) Public education and notification requirements. Pursuant to § 141.85(d), all water systems must provide notification of lead tap water monitoring results to persons served at the sites (taps) that are tested. All community water systems must conduct annual outreach to local and State health agencies pursuant to § 141.85(i). In addition:


(1) Any water system exceeding the lead action level specified at paragraph (c) of this section shall implement the public education requirements in accordance with § 141.85(a) and (b).


(2) Any water system exceeding the lead trigger level specified at paragraph (c) of this section shall provide notification to all customers with a lead service line in accordance with § 141.85(g).


(3) Any water system exceeding the lead action level specified at paragraph (c) of this section shall notify the public in accordance with the public notification requirements in subpart Q of this part.


(4) Any water system with lead service lines, galvanized requiring replacement or lead status unknown service lines in their inventory as specified in § 141.84(a) shall inform all consumers with a lead service line, galvanized requiring replacement, or a lead status unknown service line in accordance with § 141.85(e).


(5) Any water system that fails to reach its goal lead service line replacement rate as required under § 141.84(f) shall conduct outreach activities in accordance with § 141.85(h).


(h) Monitoring and analytical requirements. Tap water monitoring for lead and copper, monitoring for water quality parameters, source water monitoring for lead and copper, and analyses of the monitoring results under this subpart shall be completed in compliance with §§ 141.86, 141.87, 141.88, and 141.89.


(i) Reporting requirements. Systems shall report to the State any information required by the treatment provisions of this subpart and § 141.90.


(j) Recordkeeping requirements. Systems shall maintain records in accordance with § 141.91.


(k) Violation of national primary drinking water regulations. Failure to comply with the applicable requirements of this section and §§ 141.81 through 141.93, including requirements established by the State pursuant to the provisions in this subpart, is a violation of the national primary drinking water regulations for lead and copper.


(l) Testing in schools and child care facilities. All community water systems must collect samples from all schools and child care facilities within its distribution system in accordance with § 141.92.


[56 FR 26548, June 7, 1991; 57 FR 28788, June 29, 1992, as amended at 72 FR 57814, Oct. 10, 2007; 86 FR 4282, Jan. 15, 2021; 86 FR 31947, June 16, 2021]


§ 141.81 Applicability of corrosion control treatment steps to small, medium, and large water systems.

(a) Corrosion control treatment. This section sets forth when a system must complete the corrosion control treatment steps for 31947, June optimize corrosion control treatment based on size, whether the system has corrosion control treatment, and whether it has exceeded the lead trigger and/or action level and/or the copper action level.


(1) Large water system (serving >50,000 people). (i) Large water systems with corrosion control treatment that exceed either the lead trigger level or copper action level shall complete the corrosion control treatment steps specified in paragraph (d) of this section.


(ii) Large water systems without corrosion control treatment with 90th percentile results as calculated in accordance with § 141.80(c)(4) that exceed either the lead practical quantitation level of 0.005 mg/L or the copper action level shall complete the corrosion control treatment steps specified in paragraph (e) of this section.


(iii) Large water systems with corrosion control treatment with 90th percentile results as calculated in accordance with § 141.80(c)(4) that exceed the lead practical quantitation level but do not exceed lead trigger level or the copper action level may be required by the State to complete the corrosion control treatment steps in paragraph (d) of this section.


(2) Medium-size water systems (serving >10,000 and ≤50,000 people). (i) Medium-size water systems with corrosion control treatment that exceed either the lead trigger level or copper action level shall complete the corrosion control treatment steps specified in paragraph (d) of this section.


(ii) Medium-size water systems without corrosion control treatment that exceed either the lead or copper action level shall complete the corrosion control treatment steps specified in paragraph (e) of this section.


(iii) Medium-size water systems without corrosion control treatment that exceed the lead trigger level but do not exceed the lead or copper action levels shall complete the treatment recommendation step specified in paragraph (e)(1) of this section (Step 1). The water system shall complete the remaining steps in paragraph (e) of this section if it subsequently exceeds either the lead or copper action level.


(3) Small water systems (serving ≤10,000 people) and non-transient, non-community water systems. (i) Small and non-transient non-community water systems with corrosion control treatment that exceed the lead trigger level or the lead action level but do not exceed the copper action level, shall complete the corrosion control treatment steps specified in paragraph (d) of this section, if corrosion control treatment is approved by the State as a compliance option under § 141.93(a).


(ii) Small and non-transient, non-community water systems with corrosion control treatment that exceed the copper action level shall complete the corrosion control treatment steps specified in paragraph (d) of this section.


(iii) Small and non-transient, non-community water systems without corrosion control treatment that exceed the lead action level shall complete the corrosion control treatment steps specified in paragraph (e) of this section if corrosion control treatment is approved by the State as a compliance option under § 141.93.


(iv) Small and non-transient, non-community water systems without corrosion control treatment that exceed the copper action level shall complete the corrosion control treatment steps specified in paragraph (e) of this section.


(b) Systems deemed to have optimized corrosion control. A system is deemed to have optimal corrosion control treatment (OCCT) or re-optimized OCCT if the system satisfies one of the criteria specified in paragraphs (b)(1) through (3) of this section. Any such system deemed to have OCCT under this paragraph and which has corrosion control treatment in place shall continue to operate and maintain that treatment and meet any additional requirements that the State determines to be appropriate to ensure optimal corrosion control treatment is maintained.


(1) A small or medium-size water system without corrosion control treatment is deemed to have optimal corrosion control if the water system does not exceed the lead action level and copper action level during two consecutive 6-month tap sampling monitoring periods and thereafter remains at or below the lead trigger level and copper action level in all tap sampling periods conducted in accordance with § 141.86.


(2) A small or medium-size water system with corrosion control treatment is deemed to have optimal corrosion control treatment if the water system does not exceed the lead trigger level and copper action level during two consecutive 6-month monitoring periods conducted in accordance with § 141.86 and thereafter remains at or below the lead trigger level and copper action level in all tap sampling periods conducted in accordance with § 141.86. Small or medium-size systems with corrosion control treatment that exceed the lead trigger level but do not exceed the lead and copper action levels during two consecutive 6-month monitoring periods and thereafter remains at or below the lead and copper action levels in all tap sampling periods conducted in accordance with § 141.86 are deemed to have re-optimized optimal corrosion control treatment if the system meets the requirements of this section. Where the State has set optimal water quality parameters (OWQPs) under paragraph (d) or (e) of this section a system will not be eligible to be deemed to have optimized or re-optimized OCCT pursuant to paragraph (b) of this section.


(3) Any water system is deemed to have optimized or re-optimized corrosion control if it submits results of tap water monitoring in accordance with § 141.86 demonstrating that the 90th percentile tap water lead level is less than or equal to the lead practical quantitation level of 0.005 mg/L and does not exceed the copper action level for two consecutive 6-month tap sampling monitoring periods, and does not have optimal water quality parameters that were set by the State under paragraph (d) or (e) of this section. Any such system with 90th percentile tap sample results that thereafter exceeds the lead practical quantitation level or copper action level during any tap sampling period shall not be eligible to be deemed to have optimized OCCT in accordance with this paragraph (b)(3) without first completing the treatment steps specified in paragraph (d) or (e) of this section


(i) [Reserved]


(ii) Any water system deemed to have optimized corrosion control in accordance with this paragraph (b)(3) shall continue monitoring for lead and copper at the tap no less frequently than once every three calendar years using the reduced number of sites specified in § 141.86(c) and collecting samples at times and locations specified in § 141.86(d)(4)(v).


(iii) through (v) [Reserved]


(c) Corrosion control steps completion for small and medium-size water systems without corrosion control treatment. Any small or medium-sized system without corrosion control treatment required to complete the corrosion control steps in paragraph (e) of this section due to its exceedance of the lead or copper action level that does not exceed either the lead or copper action levels during each of two consecutive 6-month tap sample monitoring periods pursuant to § 141.86 prior to the start of Step 3 in paragraph (e)(3) of this section or Step 5 in paragraph (e)(5) of this section may cease completing the steps and is not required to complete Step 3 or Step 5, respectively, except that medium-sized systems with lead service lines and small systems with lead service lines that choose the corrosion control option pursuant to § 141.93 must complete a corrosion control treatment study under paragraph (e)(3)(i) of this section. Any system that initiates Step 5 must complete all remaining steps in paragraphs (e)(6) through (8) of this section and is not permitted to cease the steps. Any system that ceases the steps either prior to Step 3 or Step 5 and thereafter exceeds either the lead or copper action level shall not be permitted to cease the steps a second time and shall complete the applicable treatment steps beginning with the first treatment step which was not previously completed in its entirety. The State may require a water system to repeat treatment steps previously completed by the water system when the State determines that this is necessary to implement the treatment requirements of this section. The State must notify the system in writing of such a determination and explain the basis for its decision.


(d) Treatment steps and deadlines for water systems re-optimizing corrosion control treatment. Except as provided in paragraph (b) of this section or § 141.93, water systems with corrosion control treatment shall complete the following corrosion control treatment steps (described in the referenced portions of §§ 141.82, 141.86, and 141.87) by the indicated time periods.


(1) Step 1. (i) A water system other than those covered in paragraph (d)(1)(ii) of this section shall recommend re-optimized optimal corrosion control treatment (§ 141.82(c)) within six months after the end of the tap sampling period during which it exceeds either the lead trigger level or copper action level. States may approve modifications of the existing corrosion control treatment without a study for systems that exceed the lead trigger level, but do not exceed the lead or copper action level. The State shall specify re-optimized corrosion control treatment within six months of receiving the treatment recommendation. The system shall complete modifications to corrosion control treatment to have re-optimized corrosion control treatment installed within six months of the State specifying re-optimized corrosion control treatment.


(ii) A water system with lead service lines that exceeds the lead action level must harvest lead pipes from the distribution system and construct flow-through pipe loops and operate the loops with finished water within one year after the end of the tap sampling period during which it exceeds the lead action level. These water systems must proceed to Step 3 in paragraph (d)(3) of this section and conduct the corrosion control studies for re-optimization under paragraph (d)(3)(i) of this section using the pipe loops.


(2) Step 2. (i) Large water systems shall conduct the corrosion control studies for re-optimization under paragraph (d)(3) of this section (Step 3) unless the system is at or below the lead action level and the State has approved the modification of the existing corrosion control treatment made under paragraph (d)(3)(i) of this section (Step 1).


(ii) Within 12 months after the end of the tap sampling period during which a small or medium-size water system with corrosion control treatment exceeds the lead trigger level or copper action level, the State may require the water system to perform corrosion control studies for re-optimization (§ 141.82(c)(2) or (3)). If the State does not require the system to perform such studies, the State must specify re-optimized corrosion control treatment (§ 141.82(d)(2)) within the timeframes specified in paragraphs (d)(2)(ii)(A) and (B) of this section. The State must provide its determination to the system in writing.


(A) For medium-size water systems, within 12 months after the end of the tap sampling period during which such water system exceeds the lead trigger level or copper action level.


(B) For small water systems, within 18 months after the end of the tap sampling period during which such water system exceeds the lead trigger level or copper action level.


(3) Step 3. (i) Any water system with lead service lines that exceeded the lead action level shall complete the corrosion control treatment studies for re-optimization within 30 months after the end of the tap sampling period during which it exceeds the lead action level.


(ii) If the water system is required to perform corrosion control studies under paragraph (d)(2) of this section (Step 2), the water system shall complete the studies (§ 141.82(c)(2)) within 18 months after the State requires that such studies be conducted.


(4) Step 4. (i) The State shall designate re-optimized corrosion control treatment (§ 141.82(d)(3)) within six months after completion of paragraph (d)(3)(i) of this section (Step 3).


(ii) If the water system has performed corrosion control studies under paragraph (d)(2) of this section (Step 2), the State shall designate re-optimized corrosion control treatment (§ 141.82(d)(2) or (4)) within six months after completion of paragraph (d)(3)(ii) of this section (Step 3).


(5) Step 5. (i) Large water systems shall complete modifications to corrosion control treatment to have re-optimized corrosion control treatment installed within 12 months after completion of paragraph (d)(4)(i) of this section (Step 4).


(ii) Small or medium-size water systems shall install re-optimized corrosion control treatment (§ 141.82(e)(1)) within 12 months after completion of paragraph (d)(4)(ii) of this section (Step 4).


(6) Step 6. Water systems must complete follow-up sampling (§§ 141.86(d)(2) and 141.87(c)) within 12 months after completion of paragraph (d)(5)(i) or (ii) of this section (Step 5).


(7) Step 7. The State must review the water system’s installation of treatment and designate optimal water quality control parameters (§ 141.82(f)(1)) within six months of completion of paragraph (d)(6) of this section (Step 6).


(8) Step 8. The water system must operate in compliance with the State-designated optimal water quality control parameters (§ 141.82(g)) and continue to conduct tap sampling (§ 141.86(d)(3) and water quality parameter monitoring under § 141.87(d)).


(e) Treatment steps and deadlines for systems without corrosion control treatment. Except as provided in paragraph (b) of this section or § 141.93, water systems without corrosion control treatment must complete the following corrosion control treatment steps (described in the referenced portions of §§ 141.82, 141.86, and 141.87) by the indicated time periods.


(1) Step 1. (i) A water system other than those covered in paragraph (e)(1)(ii) or (iii) of this section must recommend optimal corrosion control treatment (§ 141.82(a)(1), (2), (3), or (4)) within six months after the end of the tap sampling period during which it exceeds either the lead trigger level or copper action level.


(ii) A water system with lead service lines that exceeds the lead action level must harvest lead pipes from the distribution system and construct flow-through pipe loops and operate the loops with finished water within one year after the end of the tap sampling period during which it exceeds the lead action level. These water systems must proceed to Step 3 in paragraph (e)(3) of this section and conduct the corrosion control studies for optimization under paragraph (e)(3)(i) of this section using the pipe loops.


(iii) Large water systems under paragraph (a)(1)(ii) of this section must conduct the corrosion control studies for optimization under paragraph (e)(3) of this section (Step 3).


(2) Step 2. Within 12 months after the end of the tap sampling period during which a water system exceeds the lead or copper action level, if not otherwise required by this rule, the State may require the water system to perform corrosion control studies (§ 141.82(b)(1)). The State must notify the system in writing of this requirement. If the State does not require the system to perform such studies, the State must specify optimal corrosion control treatment (§ 141.82(d)(1) or (2)) within the timeframes established in paragraphs (e)(2)(i) and (ii) of this section. The State must provide its determination to the system in writing.


(i) For medium-size water systems, within 18 months after the end of the tap sampling monitoring period during which such water system exceeds the lead trigger level or copper action level.


(ii) For small water systems, within 24 months after the end of the tap sampling monitoring period during which such water system exceeds the lead trigger level or copper action level.


(3) Step 3. (i) Large water systems with or without lead service line and medium or small systems with lead service lines that exceed the lead action level shall complete the corrosion control treatment studies for optimization within 30 months after the end of the tap sampling period during which it exceeds the lead action level.


(ii) If the State requires a water system to perform corrosion control studies under paragraph (e)(2) of this section (Step 2), the water system must complete the studies (§ 141.82(c)(1)) within 18 months after the State notifies the system in writing that such studies must be conducted.


(4) Step 4. (i) The State shall designate re-optimized corrosion control treatment (§ 141.82(d)(3)) within six months after completion of paragraph (d)(3)(i) of this section (Step 3).


(ii) If the water system has performed corrosion control studies under paragraph (e)(2) of this section (Step 2), the State must designate optimal corrosion control treatment (§ 141.82(d)(1)) within six months after completion of paragraph (e)(3) of this section (Step 3).


(5) Step 5. The water system must install optimal corrosion control treatment (§ 141.82(e)(1)) within 24 months after the State designates optimal corrosion control treatment under paragraph (e)(2) or (4) of this section (Step 2 or Step 4).


(6) Step 6. The water system shall complete follow-up sampling (§§ 141.86(d)(2)(i) and 141.87(c)) within 12 months after completion of paragraph (e)(5) of this section (Step 5).


(7) Step 7. The State must review the water system’s installation of treatment and designate optimal water quality control parameters (§ 141.82(f)(1)) within six months of completion of paragraph (e)(6) of this section (Step 6).


(8) Step 8. The water system must operate in compliance with the State-designated optimal water quality control parameters (§ 141.82(g)(1)) and continue to conduct tap sampling (§ 141.86(d)(3) and water quality parameter monitoring under § 141.87(d)).


(f) Treatment steps and deadlines for small community water systems and non-transient non-community water systems electing corrosion control treatment (CCT) as a compliance option under § 141.93, or as required by the State. Water systems selecting the corrosion control small system compliance flexibility option must complete the following steps by the indicated time periods.


(1) Step 1. A water system recommends corrosion control treatment as a small system compliance flexibility option under § 141.93(a)(2) within six months after the end of the tap sampling period during which it exceeds either the lead trigger level or the lead action level.


(2) Step 2. The State approves in writing the recommendation of corrosion control treatment as a small system compliance flexibility option or designates an alternative option in accordance with § 141.93(a) within six months of the recommendation by the water system in paragraph (f)(1) of this section (Step 1). Water systems required by the State to optimize or re-optimize corrosion control treatment must follow the schedules in paragraph (d) or (e) of this section, beginning with Step 3 in paragraph (d)(3) or (e)(3) of this section unless the State specifies optimal corrosion control treatment pursuant to either paragraph (d)(2)(ii) or (e)(2)(ii) of this section, as applicable.


[86 FR 4287, Jan. 15, 2021]


§ 141.82 Description of corrosion control treatment requirements.

This section sets forth the requirements applicable to systems and states in the designation of optimal corrosion control treatment for a system that is optimizing or reoptimizing corrosion control treatment. Each system must complete the corrosion control treatment requirements in this section as applicable to such system under § 141.81.


(a) System recommendation regarding corrosion control treatment for systems that do not contain lead service lines and systems with lead service lines that do not exceed the lead action level. (1) Any system under this paragraph (a) without corrosion control treatment that is required to recommend a treatment option in accordance with § 141.81(e) must, based on the results of lead and copper tap sampling and water quality parameter monitoring, recommend designation of one or more of the corrosion control treatments listed in paragraph (c)(1)(i) of this section. Small community water systems and non-transient non-community water systems that exceed the copper action level must comply with this paragraph (a)(1). The State may require the system to conduct additional water quality parameter monitoring to assist the State in reviewing the system’s recommendation.


(2) Any small community water system or non-transient non-community water system in this paragraph (a) without corrosion control treatment that chooses to pursue a small water system compliance flexibility option and is required to recommend an option in accordance with § 141.81(f) must, based on the results of lead tap sampling and water quality parameter monitoring, recommend designation of one of the options listed in § 141.93. Systems with no lead service lines that exceed the lead action level and select corrosion control under § 141.93(a)(2) must recommend designation of one or more of the corrosion control treatments listed in paragraph (c)(1) of this section as the optimal corrosion control treatment for that system.


(3) Any system under this paragraph (a) that exceeds the lead action level and selects corrosion control under § 141.93(a)(2) must recommend designation of one or more of the corrosion control treatments listed in paragraph (c)(1)(i) of this section as the optimal corrosion control treatment for that system. A corrosion control study under paragraph (c) of this section is not required for medium and small systems that exceed the lead trigger level but do not exceed the lead and copper action levels, unless required by the state.


(4) Any small community water system or non-transient, non-community water system with corrosion control treatment that that exceeds the lead action level and selects corrosion control under § 141.93(a)(2) must recommend designation of one or more of the corrosion control treatments listed in paragraph (c)(2) of this section as the optimal corrosion control treatment for that system.


(5) States may waive the requirement for a system to recommend OCCT if the State requires the system, in writing, to complete a corrosion control study within 3 months after the end of the tap sampling period during which the exceedance occurred. Such systems shall proceed directly to paragraph (c) of this section and complete a corrosion control study.


(b) State decision to require studies to identify initial optimal corrosion control treatment and re-optimized optimal corrosion control treatment except for large systems and small and medium systems with lead service lines that exceed the lead action level. Corrosion control treatment studies are always required for large systems that exceed the lead action level, large water systems without corrosion control treatment with 90th percentile results that exceed either the lead practical quantitation level of 0.005 mg/L or the copper action level, medium sized systems with lead service lines that exceed the lead action level, and small systems with lead service lines that exceed the lead action level and select the corrosion control treatment option under § 141.93(a).


(1) The State may require any small or medium-size system without corrosion control that exceeds either the lead or copper action level to perform corrosion control treatment studies under paragraph (c)(1) of this section to identify optimal corrosion control treatment for the system.


(2) The State may require any small or medium-size system without corrosion control that exceeds the lead trigger level but not the lead or copper action level to perform corrosion control treatment studies under paragraph (c)(1) of this section to identify optimal corrosion control treatment for the system. This corrosion control treatment shall be installed if the lead or copper action level is subsequently exceeded.


(3) The State may require any small or medium-size water systems with corrosion control treatment exceeding either the lead trigger level or copper action level to perform corrosion control treatment studies under paragraph (c)(2) of this section to identify re-optimized optimal corrosion control treatment for the system (i.e., optimal corrosion control treatment after a re-optimization evaluation).


(c) Performance of corrosion control studies. (1) Water systems without corrosion control treatment that are required to conduct corrosion control studies must complete the following:


(i) Any water system without corrosion control treatment must evaluate the effectiveness of each of the following treatments, and if appropriate, combinations of the following treatments to identify the optimal corrosion control treatment for the system:


(A) Alkalinity and pH adjustment;


(B) The addition of an orthophosphate- or silicate-based corrosion inhibitor at a concentration sufficient to maintain an effective corrosion inhibitor residual concentration in all test samples;


(C) The addition of an orthophosphate-based corrosion inhibitor at a concentration sufficient to maintain an orthophosphate residual concentration of 1 mg/L (as PO4) in all test samples; and


(D) The addition of an orthophosphate-based corrosion inhibitor at a concentration sufficient to maintain an orthophosphate residual concentration of 3 mg/L (as PO4) in all test samples.


(ii) The water system must evaluate each of the corrosion control treatments using either pipe rig/loop tests, metal coupon tests, partial-system tests, or analyses based on documented analogous treatments with other systems of similar size, water chemistry, and distribution system configurations. Large and medium systems and small community water systems and non-transient non-community water systems that select the corrosion control treatment option under § 141.93 with lead service lines that exceed the lead action level must conduct pipe rig/loop studies using harvested lead service lines from their distribution systems to assess the effectiveness of corrosion control treatment options on the existing pipe scale. For these systems, metal coupon tests can be used as a screen to reduce the number of options that are evaluated using pipe rig/loops to the current conditions and two options.


(iii) The water system must measure the following water quality parameters in any tests conducted under this paragraph (c)(1)(iii) before and after evaluating the corrosion control treatments listed in paragraphs (c)(1)(i) and (ii) of this section:


(A) Lead;


(B) Copper;


(C) pH;


(D) Alkalinity;


(E) Orthophosphate as PO4 (when an orthophosphate-based inhibitor is used); and


(F) Silicate (when a silicate-based inhibitor is used).


(iv) The water system must identify all chemical or physical constraints that limit or prohibit the use of a particular corrosion control treatment and document such constraints with one of the following:


(A) Data and documentation showing that a particular corrosion control treatment has adversely affected other drinking water treatment processes when used by another water system with comparable water quality characteristics. Systems using coupon studies to screen and/or pipe loop/rig studies to evaluate treatment options must not exclude treatment strategies from the studies based on the constraints identified in this section.


(B) Data and documentation demonstrating that the water system has previously attempted to evaluate a particular corrosion control treatment and has found that the treatment is ineffective or adversely affects other drinking water quality treatment processes. Systems using coupon studies to screen and/or pipe loop/rig studies to evaluate treatment options must not exclude treatment strategies from the studies based on the constraints identified in this section unless the treatment was found to be ineffective in a previous pipe loop/rig study.


(v) The water system must evaluate the effect of the chemicals used for corrosion control treatment on other drinking water quality treatment processes. Systems using coupon studies to screen and/or pipe loop/rig studies to evaluate treatment options shall not exclude treatment strategies from the studies based on the effects identified in this section.


(vi) On the basis of an analysis of the data generated during each evaluation, the water system must recommend to the State in writing the treatment option that the corrosion control studies indicate constitutes optimal corrosion control treatment for that system as defined in § 141.2. The water system must provide a rationale for its recommendation along with all supporting documentation specified in paragraphs (c)(2)(i) through (v) of this section.


(2) Systems with corrosion control treatment that are required to conduct corrosion control studies to determine re-optimized OCCT must complete the following:


(i) The water system must evaluate the effectiveness of the following treatments, and if appropriate, combinations of the following treatments to identify the re-optimized optimal corrosion control treatment for the system:


(A) Alkalinity and/or pH adjustment, or re-adjustment;


(B) The addition of an orthophosphate- or silicate-based corrosion inhibitor at a concentration sufficient to maintain an effective corrosion inhibitor residual concentration in all test samples if no such inhibitor is utilized;


(C) The addition of an orthophosphate-based corrosion inhibitor at a concentration sufficient to maintain an orthophosphate residual concentration of 1 mg/L (PO4) in all test samples unless the current inhibitor process already meets this residual; and


(D) The addition of an orthophosphate-based corrosion inhibitor at a concentration sufficient to maintain an orthophosphate residual concentration of 3 mg/L (PO4) in all test samples unless the current inhibitor process already meets this residual.


(ii) The water system must evaluate each of the corrosion control treatments using either pipe rig/loop tests, metal coupon tests, partial-system tests, or analyses based on documented analogous treatments with other systems of similar size, water chemistry, and distribution system configurations. If the water system has lead service lines and exceeds the lead action level, it must conduct pipe rig/loop studies using harvested lead service lines from their distribution systems to assess the effectiveness of corrosion control treatment options on the existing pipe scale. For these systems, metal coupon tests can be used as a screen to reduce the number of options that are evaluated using pipe rig/loops to the current conditions and two options.


(iii) The water system must measure the following water quality parameters in any tests conducted under this paragraph (c)(2)(iii) before and after evaluating the corrosion control treatments listed in paragraphs (c)(2)(i) and (ii) of this section:


(A) Lead;


(B) Copper;


(C) pH;


(D) Alkalinity;


(E) Orthophosphate as PO4 (when an orthophosphate-based inhibitor is used); and


(F) Silicate (when a silicate-based inhibitor is used).


(iv) The water system must identify all chemical or physical constraints that limit or prohibit the use of a particular corrosion control treatment and document such constraints with one of the following:


(A) Data and documentation showing that a particular corrosion control treatment has adversely affected other drinking water treatment processes when used by another water system with comparable water quality characteristics. Systems using coupon studies to screen and/or pipe loop/rig studies to evaluate treatment options must not exclude treatment strategies from the studies based on the constraints identified in this section.


(B) Data and documentation demonstrating that the water system has previously attempted to evaluate a particular corrosion control treatment and has found that the treatment is ineffective or adversely affects other drinking water quality treatment processes. Systems using coupon studies to screen and/or pipe loop/rig studies to evaluate treatment options shall not exclude treatment strategies from the studies based on the constraints identified in this section unless the treatment was found to be ineffective in a previous pipe loop/rig study.


(v) The water system must evaluate the effect of the chemicals used for corrosion control treatment on other drinking water quality treatment processes. Systems using coupon studies to screen and/or pipe loop/rig studies to evaluate treatment options shall not exclude treatment strategies from the studies based on the effects identified in this section.


(vi) On the basis of an analysis of the data generated during each evaluation, the water system must recommend to the State in writing the treatment option that the corrosion control studies indicate constitutes optimal corrosion control treatment for that system as defined in § 141.2. The water system must provide a rationale for its recommendation along with all supporting documentation specified in paragraph (c)(1)(i) through (v) of this section.


(d) State designation of optimized optimal corrosion control treatment and re-optimized optimal corrosion control treatment. When designating optimal corrosion control treatment, the State must consider the effects that additional corrosion control treatment will have on water quality parameters and on other drinking water quality treatment processes. The State must notify the water system of its designation of optimal corrosion control treatment in writing and explain the basis for this determination. If the State requests additional information to aid its review, the water system must provide the information.


(1) Designation of OCCT for systems without corrosion control treatment. Based upon considerations of available information including, where applicable, studies conducted under paragraph (c)(1) of this section and/or a system’s recommended corrosion control treatment option, the State must either approve the corrosion control treatment option recommended by the system or designate alternative corrosion control treatment(s) from among those listed in paragraph (c)(1)(i) of this section or, where applicable, an alternate small water system compliance flexibility option under § 141.93(a).


(2) Designation of re-optimized OCCT for systems with corrosion control treatment. Based upon considerations of available information including, where applicable, studies conducted under paragraph (c)(2) of this section and/or a system’s recommended treatment alternative, the State must either approve the corrosion control treatment option recommended by the water system or designate alternative corrosion control treatment(s) from among those listed in paragraph (c)(2)(i) of this section or, where applicable, an alternate small water system compliance flexibility option under § 141.93.


(e) Installation of optimal corrosion control treatment and re-optimization of corrosion control treatment. Each system must properly install and operate throughout its distribution system the optimal corrosion control treatment designated by the State under paragraph (d) of this section.


(f) State review of treatment and specification of optimal water quality control parameters for optimal corrosion control treatment and re-optimized corrosion control treatment. The State must evaluate the results of all lead and copper tap sampling and water quality parameter sampling submitted by the water system and determine whether the water system has properly installed and operated the optimal corrosion control treatment designated by the State in paragraph (d)(1) or (2) of this section, respectively. Upon reviewing the results of tap water and water quality parameter monitoring by the water system, both before and after the water system installs optimal corrosion control treatment, the State must designate:


(1) A minimum value or a range of values for pH measured at each entry point to the distribution system.


(2) A minimum pH value measured in all tap samples. Such a value shall be equal to or greater than 7.0, unless the State determines that meeting a pH level of 7.0 is not technologically feasible or is not necessary for the system to optimize corrosion control.


(3) If a corrosion inhibitor is used, a minimum concentration or a range of concentrations for orthophosphate (as PO4) or silicate measured at each entry point to the distribution system.


(4) If a corrosion inhibitor is used, a minimum orthophosphate or silicate concentration measured in all tap samples that the State determines is necessary to form a passivating film on the interior walls of the pipes of the distribution system. When orthophosphate is used, such an orthophosphate concentration shall be equal to or greater than 0.5 mg/L (asPO4) for OCCT designations under paragraph (d)(1) of this section and 1.0 mg/L for OCCT designations under paragraph (d)(2) of this section, unless the State determines that meeting the applicable minimum orthophosphate residual is not technologically feasible or is not necessary for optimal corrosion control treatment.


(5) If alkalinity is adjusted as part of optimal corrosion control treatment, a minimum concentration or a range of concentrations for alkalinity, measured at each entry point to the distribution system and in all tap samples.


(6) The values for the applicable water quality control parameters, previously listed in this section, shall be those that the State determines to reflect optimal corrosion control treatment for the water system. The State may designate values for additional water quality control parameters determined by the State to reflect optimal corrosion control treatment for the water system. The State must notify the system in writing of these determinations and explain the basis for its decisions.


(g) Continued operation and monitoring for optimal corrosion control treatment and re-optimized optimal corrosion control treatment. All systems optimizing or re-optimizing corrosion control must continue to operate and maintain optimal corrosion control treatment, including maintaining water quality parameters at or above minimum values or within ranges designated by the State under paragraph (f) of this section, in accordance with this paragraph (g) for all samples collected under § 141.87(d) through (f). The requirements of this paragraph (g) apply to all systems, including consecutive systems that distribute water that has been treated to control corrosion by another system, and any water system with corrosion control treatment, optimal corrosion control treatment, or re-optimized OCCT that is not required to monitor water quality parameters under § 141.87. Compliance with the requirements of this paragraph (g) shall be determined every six months, as specified under § 141.87(d). A water system is out of compliance with the requirements of this paragraph (g) for a six-month period if it has excursions for any State-specified parameter on more than nine days, cumulatively, during the period. An excursion occurs whenever the daily value for one or more of the water quality parameters measured at a sampling location is below the minimum value or outside the range designated by the State. Daily values are calculated as set out in paragraphs (g)(1) through (3) of this section. States have discretion to not include results of obvious sampling errors from this calculation. Sampling errors must still be recorded even when not included in calculations.


(1) On days when more than one measurement for the water quality parameter is collected at the sampling location, the daily value must be the average of all results collected during the day regardless of whether they are collected through continuous monitoring, grab sampling, or a combination of both. If EPA has approved an alternative formula under § 142.16(d)(1)(ii) of this chapter in the State’s application for a program revision submitted pursuant to § 142.12 of this chapter, the State’s formula shall be used to aggregate multiple measurements taken at a sampling point for the water quality parameters in lieu of the formula in this paragraph (g)(1).


(2) On days when only one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the result of that measurement.


(3) On days when no measurement is collected for the water quality parameter at the sampling location, the daily value shall be the daily value calculated on the most recent day on which the water quality parameter was measured at the sampling location.


(h) Modification of State treatment decisions for optimal corrosion control and re-optimized corrosion control. Upon its own initiative or in response to a request by a water system or other interested party, a State may modify its determination of the optimal corrosion control treatment under paragraph (d) of this section, or optimal water quality control parameters under paragraph (f) of this section. A request for modification by a system or other interested party shall be in writing, explaining why the modification is appropriate, and providing supporting documentation. The State may modify its determination where it concludes that such change is necessary to ensure that the water system continues to optimize corrosion control treatment. A revised determination must be made in writing, set forth the new treatment requirements and/or water quality parameters, explain the basis for the State’s decision, and provide an implementation schedule for completing the treatment modifications for re-optimized corrosion control treatment.


(i) Treatment decisions by EPA in lieu of the State on optimal corrosion control treatment and re-optimized corrosion control treatment. Pursuant to the procedures in § 142.19 of this chapter, EPA Regional Administrator may review optimal corrosion control treatment determinations made by a State under paragraph (d)(1) or (2), (f), or (h) of this section and issue Federal treatment determinations consistent with the requirements of paragraph (d)(1) or (2), (f), or (h) of this section where the Regional Administrator finds that:


(1) A State has failed to issue a treatment determination by the applicable deadlines contained in § 141.81;


(2) A State has abused its discretion in a substantial number of cases or in cases affecting a substantial population; or


(3) The technical aspects of a State’s determination would be indefensible in a Federal enforcement action taken against a water system.


(j) Find-and-fix assessment for tap sample sites that exceed the lead action level. The water system shall conduct the following steps, when a tap sample site exceeds the lead action level under monitoring conducted under § 141.86.


(1) Step 1: corrosion control treatment assessment. The water system must sample at a new water quality parameter site that is on the same size water main in the same pressure zone and located within a half mile of the location with the action level exceedance within 5 days of receiving the sample results. Small water systems without corrosion control treatment may have up to 14 days to collect the samples. The water system must measure the following parameters:


(i) pH;


(ii) Alkalinity;


(iii) Orthophosphate (as PO4), when an inhibitor containing an orthophosphate compound is used;


(iv) Silica, when an inhibitor containing a silicate compound is used; and


(v) Water systems with an existing water quality parameter location that meets the requirements of this section can conduct this sampling at that location.


(vi) All water systems required to meet optimal water quality control parameters but that do not have an existing water quality parameter location that meets the requirement of this section must add new sites to the minimum number of sites as described in § 141.87(g). Sites must be added until a system has twice the minimum number of sites listed in Table 1 to § 141.87(a)(2). When a system exceeds this upper threshold for the number of sites, the State has discretion to determine if the newer site can better assess the effectiveness of the corrosion control treatment and to remove existing sites during sanitary survey evaluation of OCCT.


(2) Step 2: Site assessment. Water systems shall collect a follow-up sample at any tap sample site that exceeds the action level within 30 days of receiving the sample results. These follow-up samples may use different sample volumes or different sample collection procedures to assess the source of elevated lead levels. Samples collected under this section must be submitted to the State but shall not be included in the 90th percentile calculation for compliance monitoring under § 141.86. If the water system is unable to collect a follow-up sample at a site, the water system must provide documentation to the State, explaining why it was unable to collect a follow-up sample.


(3) Step 3. Water systems shall evaluate the results of the monitoring conducted under this paragraph (j)(3) to determine if either localized or centralized adjustment of the optimal corrosion control treatment or other distribution system actions are necessary and submit the recommendation to the State within six months after the end of the tap sampling period in which the site(s) exceeded the lead action level. Corrosion control treatment modification may not be necessary to address every exceedance. Other distribution system actions may include flushing to reduce water age. Water systems must note the cause of the elevated lead level, if known from the site assessment, in their recommendation to the State as site-specific issues can be an important factor in why the system is not recommending any adjustment of corrosion control treatment or other distribution system actions. Systems in the process of optimizing or re-optimizing optimal corrosion control treatment under paragraphs (a) through (f) of this section do not need to submit a treatment recommendation for find-and-fix.


(4) Step 4. The State shall approve the treatment recommendation or specify a different approach within six months of completion of Step 3 as described in paragraph (j)(3) of this section.


(5) Step 5. If the State-approved treatment recommendation requires the water system to adjust the optimal corrosion control treatment process, the water system must complete modifications to its corrosion control treatment within 12 months after completion of Step 4 as described in paragraph (j)(4) of this section. Systems without corrosion control treatment required to install optimal corrosion control treatment must follow the schedule in § 141.81(e).


(6) Step 6. Water systems adjusting its optimal corrosion control treatment must complete follow-up sampling (§§ 141.86(d)(2) and 141.87(c)) within 12 months after completion of Step 5 as described in paragraph (j)(5) of this section.


(7) Step 7. For water systems adjusting its optimal corrosion control treatment, the State must review the water system’s modification of corrosion control treatment and designate optimal water quality control parameters (§ 141.82(f)(1)) within six months of completion of Step 6 as described in paragraph (j)(6) of this section.


(8) Step 8. For a water system adjusting its optimal corrosion control treatment, the water system must operate in compliance with the State-designated optimal water quality control parameters (§ 141.82(g)) and continue to conduct tap sampling (§§ 141.86(d)(3) and 141.87(d)).


[86 FR 4287, Jan. 15, 2021]


§ 141.83 Source water treatment requirements.

Systems shall complete the applicable source water monitoring and treatment requirements (described in the referenced portions of paragraph (b) of this section, and in §§ 141.86, and 141.88) by the following deadlines.


(a) Deadlines for completing source water treatment steps—(1) Step 1: A system exceeding the lead or copper action level shall complete lead and copper source water monitoring (§ 141.88(b)) and make a treatment recommendation to the State (§ 141.83(b)(1)) no later than 180 days after the end of the monitoring period during which the lead or copper action level was exceeded.


(2) Step 2: The State shall make a determination regarding source water treatment (§ 141.83(b)(2)) within 6 months after submission of monitoring results under step 1.


(3) Step 3: If the State requires installation of source water treatment, the system shall install the treatment (§ 141.83(b)(3)) within 24 months after completion of step 2.


(4) Step 4: The system shall complete follow-up tap water monitoring (§ 141.86(d)(2) and source water monitoring (§ 141.88(c)) within 36 months after completion of step 2.


(5) Step 5: The State shall review the system’s installation and operation of source water treatment and specify maximum permissible source water levels (§ 141.83(b)(4)) within 6 months after completion of step 4.


(6) Step 6: The system shall operate in compliance with the State-specified maximum permissible lead and copper source water levels (§ 141.83(b)(4)) and continue source water monitoring (§ 141.88(d)).


(b) Description of source water treatment requirements—(1) System treatment recommendation. Any system which exceeds the lead or copper action level shall recommend in writing to the State the installation and operation of one of the source water treatments listed in paragraph (b)(2) of this section. A system may recommend that no treatment be installed based upon a demonstration that source water treatment is not necessary to minimize lead and copper levels at users’ taps.


(2) State determination regarding source water treatment. The State shall complete an evaluation of the results of all source water samples submitted by the water system to determine whether source water treatment is necessary to minimize lead or copper levels in water delivered to users’ taps. If the State determines that treatment is needed, the State shall either require installation and operation of the source water treatment recommended by the system (if any) or require the installation and operation of another source water treatment from among the following: Ion exchange, reverse osmosis, lime softening or coagulation/filtration. If the State requests additional information to aid in its review, the water system shall provide the information by the date specified by the State in its request. The State shall notify the system in writing of its determination and set forth the basis for its decision.


(3) Installation of source water treatment. Each system shall properly install and operate the source water treatment designated by the State under paragraph (b)(2) of this section.


(4) State review of source water treatment and specification of maximum permissible source water levels. The State shall review the source water samples taken by the water system both before and after the system installs source water treatment, and determine whether the system has properly installed and operated the source water treatment designated by the State. Based upon its review, the State shall designate the maximum permissible lead and copper concentrations for finished water entering the distribution system. Such levels shall reflect the contaminant removal capability of the treatment properly operated and maintained. The State shall notify the system in writing and explain the basis for its decision.


(5) Continued operation and maintenance. Each water system shall maintain lead and copper levels below the maximum permissible concentrations designated by the State at each sampling point monitored in accordance with § 141.88. The system is out of compliance with this paragraph if the level of lead or copper at any sampling point is greater than the maximum permissible concentration designated by the State.


(6) Modification of State treatment decisions. Upon its own initiative or in response to a request by a water system or other interested party, a State may modify its determination of the source water treatment under paragraph (b)(2) of this section, or maximum permissible lead and copper concentrations for finished water entering the distribution system under paragraph (b)(4) of this section. A request for modification by a system or other interested party shall be in writing, explain why the modification is appropriate, and provide supporting documentation. The State may modify its determination where it concludes that such change is necessary to ensure that the system continues to minimize lead and copper concentrations in source water. A revised determination shall be made in writing, set forth the new treatment requirements, explain the basis for the State’s decision, and provide an implementation schedule for completing the treatment modifications.


(7) Treatment decisions by EPA in lieu of the State. Pursuant to the procedures in § 142.19, the EPA Regional Administrator may review treatment determinations made by a State under paragraphs (b) (2), (4), or (6) of this section and issue Federal treatment determinations consistent with the requirements of those paragraphs where the Administrator finds that:


(i) A State has failed to issue a treatment determination by the applicable deadlines contained in § 141.83(a),


(ii) A state has abused its discretion in a substantial number of cases or in cases affecting a substantial population, or


(iii) The technical aspects of a State’s determination would be indefensible in an expected Federal enforcement action taken against a system.


[56 FR 26548, June 7, 1991, as amended at 72 FR 57815, Oct. 10, 2007]


§ 141.84 Lead service line replacement requirements.

(a) Lead service line inventory. All water systems must develop an inventory to identify the materials of service lines connected to the public water distribution system. The inventory must meet the following requirements:


(1) All water systems must develop an initial inventory by October 16, 2024, and submit it to the primacy agency in accordance with § 141.90(e).


(2) The inventory must include all service lines connected to the public water distribution system regardless of ownership status (e.g., where service line ownership is shared, the inventory would include both the portion of the service line owned by the water system and the customer-owned portion of the service line).


(3) A water system must use any information on lead and galvanized iron or steel that it has identified pursuant to § 141.42(d) when conducting the inventory of service lines in its distribution system for the initial inventory under paragraph (a)(1) of this section. The water system must also review the sources of information listed in paragraphs (a)(3)(i) through (iv) of this section to identify service line materials for the initial inventory. The water system may use other sources of information not listed in paragraphs (a)(3)(i) through (iv) of this section if approved by the State.


(i) All construction and plumbing codes, permits, and existing records or other documentation which indicates the service line materials used to connect structures to the distribution system.


(ii) All water system records, including distribution system maps and drawings, historical records on each service connection, meter installation records, historical capital improvement or master plans, and standard operating procedures.


(iii) All inspections and records of the distribution system that indicate the material composition of the service connections that connect a structure to the distribution system.


(iv) Any resource, information, or identification method provided or required by the State to assess service line materials.


(4) Each service line, or portion of the service line where ownership is split, must be categorized in the following manner:


(i) “Lead” where the service line is made of lead.


(ii) “Galvanized Requiring Replacement” where a galvanized service line is or was at any time downstream of a lead service line or is currently downstream of a “Lead Status Unknown” service line. If the water system is unable to demonstrate that the galvanized service line was never downstream of a lead service line, it must presume there was an upstream lead service line.


(iii) “Non-lead” where the service line is determined through an evidence-based record, method, or technique not to be lead or galvanized requiring replacement. The water system may classify the actual material of the service line (i.e., plastic or copper) as an alternative to classifying it as “Non-lead.”


(iv) “Lead Status Unknown” where the service line material is not known to be lead, galvanized requiring replacement, or a non-lead service line, such as where there is no documented evidence supporting material classification. The water system may classify the line as “Unknown” as an alternative to classifying it as “Lead Status Unknown,” however, all requirements that apply to “Lead Status Unknown” service lines must also apply to those classified as “Unknown.” Water systems may elect to provide more information regarding their unknown lines as long as the inventory clearly distinguishes unknown service lines from those where the material has been verified through records or inspection.


(5) Water systems shall identify and track service line materials in the inventory as they are encountered in the course of its normal operations (e.g., checking service line materials when reading water meters or performing maintenance activities).


(6) Water systems must update the inventory based on all applicable sources described in paragraphs (a)(3) and (5) of this section and any lead service line replacements or service line material inspections that may have been conducted. The water system may use other sources of information if approved by the State and must use other sources of information provided or required by the State. Water systems must submit the updated inventory to the State in accordance with § 141.90(e). The inventory updates must be reflected in the publicly accessible inventory no less frequently than when required to be submitted to the State.


(i) Water systems whose inventories contain only non-lead service lines are not required to provide inventory updates to the State or to the public. If, in the future, such a water system finds a lead service line within its system, it must prepare an updated inventory in accordance with paragraph (a) of this section on a schedule established by the State.


(ii) [Reserved]


(7) To calculate the number of service line replacements applicable to paragraphs (f) and (g) of this section, the replacement rate must be applied to the sum of known lead and galvanized requiring replacement service lines when the system first exceeds the trigger or action level plus the number of lead status unknown service lines in the beginning of each year of a system’s annual goal or mandatory lead service line replacement program.


(i) Each service line shall count only once for purposes of calculating the required number of service line replacements, even where the ownership of the service line is split and both the customer-owned and system-owned portions require replacement.


(ii) The number of service lines requiring replacement must be updated annually to subtract the number of lead status unknown service lines that were discovered to be non-lead and to add the number of non-lead service lines that were discovered to be a lead or galvanized requiring replacement service line.


(iii) Verification of a lead status unknown service line as non-lead in the inventory does not count as a service line replacement.


(8) The service line materials inventory must be publicly accessible.


(i) The inventory must include a location identifier, such as a street address, block, intersection, or landmark, associated with each lead service line and galvanized requiring replacement service line. Water systems may, but are not required to, include a locational identifier for lead status unknown service lines or list the exact address of each service line.


(ii) Water systems serving greater than 50,000 persons must make the publicly accessible inventory available online.


(9) When a water system has no lead, galvanized requiring replacement, or lead status unknown service lines (regardless of ownership) in its inventory, it may comply with the requirements in paragraph (a)(8) of this section using a written statement, in lieu of the inventory, declaring that the distribution system has no lead service lines or galvanized requiring replacement service lines. The statement must include a general description of all applicable sources described in paragraphs (a)(3), (5), and (6) of this section used to make this determination.


(10) Instructions to access the service line inventory (including inventories consisting only of a statement in accordance with paragraph (a)(9) of this section) must be included in Consumer Confidence Report in accordance with § 141.153(d)(4)(xi).


(b) Lead service line replacement plan. All water systems with one or more lead, galvanized requiring replacement, or lead status unknown service lines in their distribution system must, by October 16, 2024, submit a lead service line replacement plan to the State in accordance with § 141.90(e). The lead service line replacement plan must be sufficiently detailed to ensure a system is able to comply with the lead service line replacement requirements in accordance with this section. The plan must include a description of:


(1) A strategy for determining the composition of lead status unknown service lines in its inventory;


(2) A procedure for conducting full lead service line replacement;


(3) A strategy for informing customers before a full or partial lead service line replacement;


(4) For systems that serve more than 10,000 persons, a lead service line replacement goal rate recommended by the system in the event of a lead trigger level exceedance;


(5) A procedure for customers to flush service lines and premise plumbing of particulate lead;


(6) A lead service line replacement prioritization strategy based on factors including but not limited to the targeting of known lead service lines, lead service line replacement for disadvantaged consumers and populations most sensitive to the effects of lead; and


(7) A funding strategy for conducting lead service line replacements which considers ways to accommodate customers that are unable to pay to replace the portion they own.


(c) Operating procedures for replacing lead goosenecks, pigtails, or connectors. (1) The water system must replace any lead gooseneck, pigtail, or connector it owns when encountered during planned or unplanned water system infrastructure work.


(2) The water system must offer to replace a customer-owned lead gooseneck, pigtail, or connector; however, the water system is not required to bear the cost of replacement of the customer-owned parts.


(3) The water system is not required to replace a customer-owned lead gooseneck, pigtail, or connector if the customer objects to its replacement.


(4) The replacement of a lead gooseneck, pigtail, or connector does not count for the purposes of meeting the requirements for goal-based or mandatory lead service line replacements, in accordance with paragraphs (f) and (g) of this section, respectively.


(5) Upon replacement of any gooseneck, pigtail, or connector that is attached to a lead service line, the water system must follow risk mitigation procedures specified in § 141.85(f)(2).


(6) The requirements of paragraphs (c)(1), (2), (3), and (5) of this section do not apply if state law includes lead connectors in the definition of lead service lines, prohibits partial lead service line replacements, and requires systems to remove all lead service lines irrespective of a system’s 90th percentile lead level.


(d) Requirements for conducting lead service line replacement that may result in partial replacement. (1) Any water system that plans to partially replace a lead service line (e.g., replace only the portion of a lead service line that it owns) in coordination with planned infrastructure work must provide notice to the owner of the affected service line, or the owner’s authorized agent, as well as non-owner resident(s) served by the affected service line at least 45 days prior to the replacement. The notice must explain that the system will replace the portion of the line it owns and offer to replace the portion of the service line not owned by the water system. The water system is not required to bear the cost of replacement of the portion of the affected service line not owned by the water system.


(i) Before the affected service line is returned to service, the water system must provide notification meeting the content requirements of § 141.85(a) explaining that consumers may experience a temporary increase of lead levels in their drinking water due to the replacement, information about the health effects of lead, and actions consumers can take to minimize their exposure to lead in drinking water. In instances where multi-family dwellings are served by the affected service line to be partially replaced, the water system may elect to post the information at a conspicuous location instead of providing individual notification to all residents.


(ii) The water system must provide information about service line flushing in accordance with the procedure developed in paragraph (b)(5) of this section before the affected service line is returned to service.


(iii) The water system must provide the consumer with a pitcher filter or point-of-use device certified by an American National Standards Institute accredited certifier to reduce lead, six months of replacement cartridges, and instructions for use before the affected service line is returned to service. If the affected service line serves more than one residence or non-residential unit (e.g., a multi-unit building), the water system must provide a filter, six months of replacement cartridges and use instructions to every residence in the building.


(iv) The water system must offer to collect a follow up tap sample between three months and six months after completion of any partial replacement of a lead service line. The water system must provide the results of the sample in accordance with § 141.85(d).


(2) Any water system that replaces the portion of the lead service line it owns due to an emergency repair, must provide notice and risk mitigation measures to the persons served by the affected service line in accordance with paragraphs (d)(1)(i) through (iii) of this section before the affected service line is returned to service.


(3) When a water system is notified by the customer that the customer’s portion of the lead service line will be replaced, the water system must make a good faith effort to coordinate simultaneous replacement of its portion of the service line. If simultaneous replacement cannot be conducted, the water system must replace its portion as soon as practicable but no later than 45 days from the date the customer replaces its portion of the lead service line. The water system must provide notification and risk mitigation measure in accordance with paragraphs (d)(1)(i) through (iii) of this section. If the water system fails to replace its portion of the lead service line within 45 days from the date the customer replaces the customer’s portion of the lead service line, the water system must notify the State within 30 days of failing to meet the deadline in accordance with § 141.90(e) and complete the replacement no later than 180 days of the date the customer replaces its portion.


(4) When a water system is notified or otherwise learns that replacement of a customer-owned lead service line has occurred within the previous six months and left in place a system-owned lead service line, the water system must replace its portion within 45 days from the day of becoming aware of the customer replacement. The water system must provide notification and risk mitigation measures in accordance with paragraphs (d)(1)(i) through (iii) of this section within 24 hours of becoming aware of the customer replacement. If the water system fails to replace its portion of the affected service line within 45 days of becoming aware of the customer replacement, it must notify the State within 30 days of failing to meet the deadline in accordance with § 141.90(e). The water system must complete the replacement no later than 180 days after the date the customer replaces its portion.


(5) When a water system is notified or otherwise learns of a replacement of a customer-owned lead service line which has occurred more than six months in the past, the water system is not required to complete the lead service line replacement of the system-owned portion under this paragraph (d)(5), however the system-owned portion must still be included in the calculation of a lead service line replacement rate under paragraph (a)(7) of this section.


(e) Requirements for conducting full lead service line replacement. Any water system that conducts a full lead service line replacement must provide notice to the owner of the affected service line, or the owner’s authorized agent, as well as non-owner resident(s) served by the affected service line within 24 hours of completion of the replacement. The water system is not required to bear the cost of replacement of the portion of the lead service line not owned by the water system.


(1) The notification must meet the content requirements of § 141.85(a) explaining that consumers may experience a temporary increase of lead levels in their drinking water due to the replacement, information about the health effects of lead, and actions consumers can take to minimize their exposure to lead in drinking water. In instances where multi-family dwellings are served by the lead service line to be replaced, the water system may elect to post the information at a conspicuous location instead of providing individual notification to all residents.


(2) The water system must provide information about service line flushing in accordance with the procedure developed under paragraph (b)(5) of this section before the replaced service line is returned to service.


(3) The water system must provide the consumer with a pitcher filter or point-of-use device certified by an American National Standards Institute accredited certifier to reduce lead, six months of replacement cartridges, and instructions for use before the replaced service line is returned to service. If the lead service line serves more than one residence or non-residential unit (e.g., a multi-unit building), the water system must provide a filter and six months of replacement cartridges and use instructions to every residence in the building.


(4) The water system must offer to the consumer to take a follow up tap sample between three months and six months after completion of any full replacement of a lead service line. The water system must provide the results of the sample to the consumer in accordance with paragraph (d) of this section.


(f) Goal-based full lead service line replacement for water systems whose 90th percentile lead level is above the trigger level but at or below the lead action level. Water systems that serve more than 10,000 persons whose 90th percentile lead level from tap samples taken pursuant to § 141.86 is above the lead trigger level but at or below the lead action level must conduct goal-based full lead service line replacement at a rate approved by the state.


(1) The water system must calculate the number of full lead service line replacements it must conduct annually in accordance with paragraph (a)(7) of this section.


(2) Replacement of lead service lines must be conducted in accordance with the requirements of paragraph (d) or (e) of this section.


(3) Only full lead service line replacements count towards a water system’s annual replacement goal. Partial lead service line replacements do not count towards the goal.


(4) The water system must provide information to customers with lead, galvanized requiring replacement, or lead status unknown service lines as required in § 141.85(g).


(5) Any water system that fails to meet its lead service line replacement goal must:


(i) Conduct public outreach activities pursuant to § 141.85(h) until either the water system meets its replacement goal, or tap sampling shows the 90th percentile of lead is at or below the trigger level for two consecutive one-year monitoring periods.


(ii) Recommence its goal-based lead service line replacement program pursuant to this paragraph (f)(5)(ii) if the 90th percentile lead level anytime thereafter exceeds the lead trigger level but is at or below the lead action level.


(6) The first year of lead service line replacement shall begin on the first day following the end of the tap sampling period in which the lead trigger level was exceeded. If sampling is required annually or less frequently, the end of the tap sampling monitoring period is September 30 of the calendar year in which the sampling occurs. If the State has established an alternate monitoring period, then the end of the monitoring period will be the last day of that period.


(g) Mandatory full lead service line replacement for water systems whose 90th percentile lead level exceeds the lead action level. Water systems serving more than 10,000 persons that exceed the lead action level in tap samples taken pursuant to § 141.86 must conduct mandatory full lead service line replacement at an average annual rate of at least three percent, calculated on a two-year rolling basis.


(1) The average annual number of full lead service line replacements must be calculated in accordance with paragraph (a)(7) of this section.


(2) Lead service line replacement must be conducted in accordance with the requirements of paragraphs (d) and (e) of this section.


(3) Only full lead service line replacement count towards a water system’s mandatory replacement rate of at least three percent annually. Partial lead service line replacements do not count towards the mandatory replacement rate.


(4) Water systems must provide information to customers with lead, galvanized requiring replacement, or lead status unknown service lines consistent with § 141.85(g).


(5) Community water systems serving 10,000 or fewer persons and Non-transient non-community water systems for which the state has approved or designated lead service line replacement as a compliance option must conduct lead service line replacement as described in § 141.93(a)(1). Replacement of lead service lines must be conducted in accordance with the requirements of paragraphs (d) and (e) of this section.


(6) A water system may cease mandatory lead service line replacement when it has conducted a cumulative percentage of replacements greater than or equal to 3%, or other percentage specified in paragraph (g)(9) of this section, of the service lines specified in paragraph (a)(7) of this section multiplied by the number of years that elapsed from when the system most recently began mandatory lead service line replacement and the date on which the system’s 90th percentile lead level, in accordance with § 141.80(c)(4), has been calculated to be at or below the lead action level during each of four consecutive six-month tap sampling monitoring periods. If tap samples collected in any such system thereafter exceed the lead action level, the system shall recommence mandatory lead service line replacement at the same two-year rolling average rate, unless the State has designated an alternate replacement rate under paragraph (g)(9) of this section.


(7) The water system may also cease mandatory lead service line replacement if the system has no remaining lead status unknown service lines in its inventory and obtains refusals to conduct full lead service line replacement or non-responses from every remaining customer in its distribution system served by either a full or partial lead service line, or a galvanized requiring replacement service line. For purposes of this paragraph (g)(7) and in accordance with § 141.90(e), a water system must provide documentation to the State of customer refusals including a refusal signed by the customer, documentation of a verbal statement made by the customer refusing replacement, or documentation of no response from the customer after the water system made a minimum of two good faith attempts to reach the customer regarding full lead service line replacement. If the water system’s 90th percentile exceeds the lead action level again, it must contact all customers served by a full or partial lead service line or a galvanized requiring replacement service line with an offer to replace the customer-owned portion. Nothing in this paragraph (g)(7) requires the water system to bear the cost of replacement of the customer-owned lead service line.


(8) The first year of lead service line replacement shall begin on the first day following the end of the tap sampling period in which lead action level was exceeded.


(9) The State shall require a system to replace lead service lines on a shorter schedule than that required by this section, taking into account the number of lead service lines in the system, where the State determines a shorter replacement schedule is feasible. The State shall make this determination in writing and notify the system of its finding within six months after the system is required to begin lead service line replacement under paragraph (g) of this section.


(h) Reporting to demonstrate compliance to State. To demonstrate compliance with paragraphs (a) through (g) of this section, a system shall report to the State the information specified in § 141.90(e).


[86 FR 4290, Jan. 15, 2021, as amended at 86 FR 31947, June 16, 2021]


§ 141.85 Public education and supplemental monitoring and mitigation requirements.

All water systems must deliver a consumer notice of lead tap water monitoring results to persons served by the water system at sites that are sampled, as specified in paragraph (d) of this section. A water system with lead, galvanized requiring replacement, or lead status unknown service lines must deliver public education materials to persons with a lead, galvanized requiring replacement, or lead status unknown service line as specified in paragraphs (e) through (g) of this section. All community water systems must conduct annual outreach to local and State health agencies as outlined in paragraph (i) of this section. A community water system serving more than 10,000 persons that fails to meet its annual lead service line replacement goal as required under § 141.84(f) shall conduct outreach activities as specified in paragraph (h) of this section. A water system that exceeds the lead action level based on tap water samples collected in accordance with § 141.86 shall deliver the public education materials contained in paragraph (a) of this section and in accordance with the requirements in paragraph (b) of this section. Water systems that exceed the lead action level shall offer to sample the tap water of any customer who requests it in accordance with paragraph (c) of this section. All small community water systems and non-transient non-community water systems that elect to implement POU devices under § 141.93 must provide public education materials to inform users how to properly use POU devices in accordance with paragraph (j) of this section.


(a) Content of written public education materials—


(1) Community water systems and non-transient non-community water systems. Water systems must include the following elements in printed materials (e.g., brochures and pamphlets) in the same order as listed in paragraphs (a)(1)(i) through (vii) of this section. In addition, language in paragraphs (a)(1)(i), (ii), and (vi) of this section must be included in the materials, exactly as written, except for the text in brackets in paragraphs (a)(1)(i), (ii), and (vi) of this section for which the water system must include system-specific information. Any additional information presented by a water system must be consistent with the information in paragraphs (a)(1) through (vii) of this section and be in plain language that can be understood by the general public. Water systems must submit all written public education materials to the State prior to delivery. The State may require the system to obtain approval of the content of written public materials prior to delivery. Water systems may change the mandatory language in paragraphs (a)(1)(i) and (ii) of this section only with State approval.


(i) IMPORTANT INFORMATION ABOUT LEAD IN YOUR DRINKING WATER. [INSERT NAME OF WATER SYSTEM] found elevated levels of lead in drinking water in some homes/buildings. Lead can cause serious health problems, especially for pregnant women and young children. Please read this information closely to see what you can do to reduce lead in your drinking water.


(ii) Health effects of lead. Exposure to lead in drinking water can cause serious health effects in all age groups. Infants and children can have decreases in IQ and attention span. Lead exposure can lead to new learning and behavior problems or exacerbate existing learning and behavior problems. The children of women who are exposed to lead before or during pregnancy can have increased risk of these adverse health effects. Adults can have increased risks of heart disease, high blood pressure, kidney or nervous system problems.


(iii) Sources of lead. (A) Explain what lead is.


(B) Explain possible sources of lead in drinking water and how lead enters drinking water. Include information on home/building plumbing materials and service lines that may contain lead.


(C) Discuss other important sources of lead exposure in addition to drinking water (e.g., paint).


(iv) Discuss the steps the consumer can take to reduce their exposure to lead in drinking water.


(A) Encourage running the water to flush out the lead.


(B) Explain concerns with using hot water from the tap and specifically caution against the use of hot water for preparing baby formula.


(C) Explain that boiling water does not reduce lead levels.


(D) Discuss other options consumers can take to reduce exposure to lead in drinking water, such as alternative sources or treatment of water.


(E) Suggest that parents have their child’s blood tested for lead.


(v) Explain why there are elevated levels of lead in the system’s drinking water (if known) and what the water system is doing to reduce the lead levels in homes/buildings in this area.


(vi) For more information, call us at [INSERT YOUR NUMBER] [(IF APPLICABLE), or visit our Web site at [INSERT YOUR WEB SITE HERE]]. For more information on reducing lead exposure around your home/building and the health effects of lead, visit EPA’s Web site at http://www.epa.gov/lead or contact your health care provider.


(vii) Information on lead service lines. For systems with lead service lines, discuss opportunities to replace lead service lines and explain how to access the service line inventory so the consumer can find out if they have a lead service line. Include information on programs that provide financing solutions to assist property owners with replacement of their portion of a lead service line, and a statement that the water system is required to replace its portion of a lead service line when the property owner notifies them they are replacing their portion of the lead service line.


(2) Community water systems. In addition to including the elements specified in paragraph (a)(1) of this section, community water systems must:


(i) Tell consumers how to get their water tested.


(ii) Discuss lead in plumbing components and the difference between low lead and lead free.


(b) Delivery of public education materials. (1) For public water systems serving a large proportion of non-English speaking consumers, as determined by the State, the public education materials must contain information in the appropriate language(s) regarding the importance of the notice or contain a telephone number or address where persons served may contact the water system to obtain a translated copy of the public education materials or to request assistance in the appropriate language.


(2) A community water system that exceeds the lead action level on the basis of tap water samples collected in accordance with § 141.86, and that is not already conducting public education tasks under this section, must conduct the public education tasks under this section within 60 days after the end of the tap sampling period in which the exceedance occurred:


(i) Deliver printed materials meeting the content requirements of paragraph (a) of this section to all bill paying customers.


(ii)(A) Contact customers who are most at risk by delivering education materials that meet the content requirements of paragraph (a) of this section to local public health agencies even if they are not located within the water system’s service area, along with an informational notice that encourages distribution to all the organization’s potentially affected customers or community water system’s users. The water system must contact the local public health agencies directly by phone or in person. The local public health agencies may provide a specific list of additional community based organizations serving target populations, which may include organizations outside the service area of the water system. If such lists are provided, systems must deliver education materials that meet the content requirements of paragraph (a) of this section to all organizations on the provided lists.


(B) Contact customers who are most at risk by delivering materials that meet the content requirements of paragraph (a) of this section to the following organizations listed in paragraphs (b)(2)(ii)(B)(1) through (7) of this section that are located within the water system’s service area, along with an informational notice that encourages distribution to all the organization’s potentially affected customers or community water system’s users:


(1) Schools, child care facilities, and school boards.


(2) Women, Infants and Children (WIC) and Head Start programs.


(3) Public and private hospitals and medical clinics.


(4) Pediatricians.


(5) Family planning clinics.


(6) Local welfare agencies.


(7) Obstetricians-Gynecologists and Midwives.


(iii) No less often than quarterly, provide information on or in each water bill as long as the system exceeds the action level for lead. The message on the water bill must include the following statement exactly as written except for the text in brackets for which the water system must include system-specific information: [INSERT NAME OF WATER SYSTEM] found high levels of lead in drinking water in some homes. Lead can cause serious health problems. For more information please call [INSERT NAME OF WATER SYSTEM] [or visit (INSERT YOUR WEB SITE HERE)]. The message or delivery mechanism can be modified in consultation with the State; specifically, the State may allow a separate mailing of public education materials to customers if the water system cannot place the information on water bills.


(iv) Post material meeting the content requirements of paragraph (a) of this section on the water system’s Web site if the system serves a population greater than 100,000.


(v) Submit a press release to newspaper, television and radio stations.


(vi) In addition to paragraphs (b)(2)(i) through (v) of this section, systems must implement at least three activities from one or more categories listed below. The educational content and selection of these activities must be determined in consultation with the State.


(A) Public Service Announcements.


(B) Paid advertisements.


(C) Public Area Information Displays.


(D) E-mails to customers.


(E) Public Meetings.


(F) Household Deliveries.


(G) Targeted Individual Customer Contact.


(H) Direct material distribution to all multi-family homes and institutions.


(I) Other methods approved by the State.


(vii) For systems that are required to conduct monitoring annually or less frequently, the end of the tap sampling period is September 30 of the calendar year in which the sampling occurs, or, if the State has established an alternate tap sampling period, the last day of that period.


(3) As long as a community water system exceeds the action level, it must repeat the activities pursuant to paragraph (b)(2) of this section as described in paragraphs (b)(3)(i) through (iv) of this section.


(i) A community water system shall repeat the tasks contained in paragraphs (b)(2)(i), (ii) and (vi) of this section every 12 months.


(ii) A community water system shall repeat tasks contained in paragraph (b)(2)(iii) of this section with each billing cycle.


(iii) A community water system serving a population greater than 100,000 shall post and retain material on a publicly accessible Web site pursuant to paragraph (b)(2)(iv) of this section.


(iv) The community water system shall repeat the task in paragraph (b)(2)(v) of this section twice every 12 months on a schedule agreed upon with the State. The State can allow activities in paragraph (b)(2) of this section to extend beyond the 60-day requirement if needed for implementation purposes on a case-by-case basis; however, this extension must be approved in writing by the State in advance of the 60-day deadline.


(4) Within 60 days after the end of the tap sampling period in which the exceedance occurred (unless it already is repeating public education tasks pursuant to paragraph (b)(5) of this section), a non-transient non-community water system shall deliver the public education materials specified by paragraph (a) of this section as follows:


(i) Post informational posters on lead in drinking water in a public place or common area in each of the buildings served by the system; and


(ii) Distribute informational pamphlets and/or brochures on lead in drinking water to each person served by the non-transient non-community water system. The State may allow the system to utilize electronic transmission in lieu of or combined with printed materials as long as it achieves at least the same coverage.


(iii) For systems that are required to conduct monitoring annually or less frequently, the end of the tap sampling period is September 30 of the calendar year in which the sampling occurs, or, if the State has established an alternate tap sampling period, the last day of that period.


(5) A non-transient non-community water system shall repeat the tasks contained in paragraph (b)(4) of this section at least once during each calendar year in which the system exceeds the lead action level. The State can allow activities in (b)(4) of this section to extend beyond the 60-day requirement if needed for implementation purposes on a case-by-case basis; however, this extension must be approved in writing by the State in advance of the 60-day deadline.


(6) A water system may discontinue delivery of public education materials if the system is at or below the lead action level during the most recent six-month tap sampling monitoring period conducted pursuant to § 141.86. Such a system shall recommence public education in accordance with this section if it subsequently exceeds the lead action level during any tap sampling period.


(7) A community water system may apply to the State, in writing (unless the State has waived the requirement for prior State approval), to use only the text specified in paragraph (a)(1) of this section in lieu of the text in paragraphs (a)(1) and (a)(2) of this section and to perform the tasks listed in paragraphs (b)(4) and (b)(5) of this section in lieu of the tasks in paragraphs (b)(2) and (b)(3) of this section if:


(i) The system is a facility, such as a prison or a hospital, where the population served is not capable of or is prevented from making improvements to plumbing or installing point of use treatment devices; and


(ii) The system provides water as part of the cost of services provided and does not separately charge for water consumption.


(8) A community water system serving 3,300 or fewer people may limit certain aspects of their public education programs as follows:


(i) With respect to the requirements of paragraph (b)(2)(vi) of this section, a system serving 3,300 or fewer must implement at least one of the activities listed in that paragraph.


(ii) With respect to the requirements of paragraph (b)(2)(ii) of this section, a system serving 3,300 or fewer people may limit the distribution of the public education materials required under that paragraph to facilities and organizations served by the system that are most likely to be visited regularly by pregnant women and children.


(iii) With respect to the requirements of paragraph (b)(2)(v) of this section, the State may waive this requirement for systems serving 3,300 or fewer persons as long as system distributes notices to every household served by the system.


(c) Supplemental monitoring and notification of results. A water system that fails to meet the lead action level on the basis of tap samples collected in accordance with § 141.86 shall offer to sample the tap water of any customer who requests it. The system is not required to pay for collecting or analyzing the sample, nor is the system required to collect and analyze the sample itself.


(d) Notification of results—(1) Reporting requirement. All water systems must provide a notice of the individual tap results from lead tap water monitoring carried out under the requirements of § 141.86 to the persons served by the water system at the specific sampling site from which the sample was taken (e.g., the occupants of the building where the tap was sampled).


(2) Timing of notification. A water system must provide the consumer notice as soon as practicable but no later than the following timeframes:


(i) For individual samples that do not exceed 15 µg/L of lead, no later than 30 days after the water system learns of the tap monitoring results.


(ii) For individual samples that exceed 15 µg/L of lead, as soon as practicable but no later than 3 calendar days after the water system learns of the tap monitoring results. Water systems that choose to mail the notification must assure those letters are postmarked within three days.


(3) Content. The consumer notice must include the results of lead tap water monitoring for the tap that was tested, an explanation of the health effects of lead, list steps consumers can take to reduce exposure to lead in drinking water and contact information for the water utility. The notice must also provide the maximum contaminant level goal and the action level for lead and the definitions for these two terms from § 141.153(c).


(4) Delivery. (i) For lead tap sample results that do not exceed 15 µg/L, the water systems must provide consumer notice to persons served at the tap that was sampled, by mail or by another method approved by the State. For example, upon approval by the State, a non-transient non-community water system could post the results on a bulletin board in the facility to allow users to review the information.


(ii) For lead tap sample results that exceed 15 µg/L, the water systems must provide consumer notice to persons served by the tap that was sampled; such notice must be provided electronically or by phone, hand delivery, by mail, or another method approved by the State.


(e) Notification of known or potential service line containing lead—(1) Notification requirements. All water systems with lead, galvanized requiring replacement, or lead status unknown service lines in their inventory pursuant to § 141.84(a) must inform all persons served by the water system at the service connection with a lead, galvanized requiring replacement, or lead status unknown service line.


(2) Timing of notification. A water system must provide the initial notification within 30 days of completion of the lead service line inventory required under § 141.84 and repeat the notification on an annual basis until the entire service connection is no longer a lead, galvanized requiring replacement, or lead status unknown service line. For new customers, water systems shall also provide the notice at the time of service initiation.


(3) Content—(i) Persons served by a confirmed lead service line. The notice must include a statement that the person’s service line is lead, an explanation of the health effects of lead that meets the requirements of paragraph (a)(1)(ii) of this section, steps persons at the service connection can take to reduce exposure to lead in drinking water, information about opportunities to replace lead service lines as well as programs that provide financing solutions to assist property owners with replacement of their portion of a lead service line, and a statement that the water system is required to replace its portion of a lead service line when the property owner notifies them they are replacing their portion of the lead service line.


(ii) Persons served by a galvanized requiring replacement service line. The notice must include a statement that the person’s service line is galvanized requiring replacement, an explanation of the health effects of lead, steps persons at the service connection can take to reduce exposure to lead in drinking water, and information about opportunities for replacement of the service line.


(iii) Persons served by a lead status unknown service line. The notice must include a statement that the person’s service line material is unknown but may be lead, an explanation of the health effects of lead that meets the requirements of paragraph (a)(1)(ii) of this section, steps persons at the service connection can take to reduce exposure to lead in drinking water, and information about opportunities to verify the material of the service line.


(4) Delivery. The notice must be provided to persons served by the water system at the service connection with a lead, galvanized requiring replacement, or lead status unknown service line, by mail or by another method approved by the State.


(f) Notification due to a disturbance to a known or potential service line containing lead. (1) Water systems that cause disturbance to a lead, galvanized requiring replacement, or lead status unknown service line that results in the water to an individual service line being shut off or bypassed, such as operating a valve on a service line or meter setter, and without conducting a partial or full lead service line replacement, must provide the persons served by the water system at the service connection with information about the potential for elevated lead levels in drinking water as a result of the disturbance as well as instructions for a flushing procedure to remove particulate lead. The water system must comply with the requirements in this paragraph (f)(1) before the affected service line is returned to service.


(2) If the disturbance of a lead, galvanized requiring replacement, or lead status unknown service line results from the replacement of an inline water meter, a water meter setter, or gooseneck, pigtail, or connector, the water system must provide the person served by the water system at the service connection with information about the potential for elevated lead levels in drinking water as a result of the disturbance, public education materials that meet the content requirements in paragraph (a) of this section, a pitcher filter or point-of-use device certified by an American National Standards Institute accredited certifier to reduce lead, instructions to use the filter, and six months of filter replacement cartridges. The water system must comply with the requirements of this paragraph (f)(2) before the affected service line is returned to service.


(3) A water system that conducts a partial or full lead service line replacement must follow procedures in accordance with the requirements in § 141.84(d)(1)(i) through (iv) and (e)(1)(i) through (iv), respectively.


(g) Information for persons served by known or potential service lines containing lead when a system exceeds the lead trigger level—(1) Content. All water systems with lead service lines that exceed the lead trigger level of 10 µg/L must provide persons served by the water system at the service connection with a lead, galvanized requiring replacement, or lead status unknown service line information regarding the water system’s lead service line replacement program and opportunities for replacement of the lead service line.


(2) Timing. Waters systems must send notification within 30 days of the end of the tap sampling period in which the trigger level exceedance occurred. Water systems must repeat the notification annually until the results of sampling conducted under § 141.86 are at or below the lead trigger level.


(3) Delivery. The notice must be provided to persons served at the service connection with a lead, galvanized requiring replacement, or lead status unknown service line, by mail or by another method approved by the State.


(h) Outreach activities for failure to meet the lead service line replacement goal. (1) In the first year after a community water system that serves more than 10,000 persons does not meet its annual lead service line replacement goal as required under § 141.84(f), it must conduct one outreach activity from the following list in the following year until the water system meets its replacement goal or until tap sampling shows that the 90th percentile for lead is at or below the trigger level of 10 µg/L for two consecutive tap sampling monitoring periods:


(i) Send certified mail to customers with a lead or galvanized requiring replacement service line to inform them about the water system’s goal-based lead service line replacement program and opportunities for replacement of the service line.


(ii) Conduct a townhall meeting.


(iii) Participate in a community event to provide information about its lead service line replacement program and distribute public education materials that meet the content requirements in paragraph (a) of this section.


(iv) Contact customers by phone, text message, email, or door hanger.


(v) Use another method approved by the State to discuss the lead service line replacement program and opportunities for lead service line replacement.


(2) After the first year following a trigger level exceedance, any water system that thereafter continues to fail to meet its lead service line replacement goal must conduct one activity from paragraph (h)(1) of this section and two additional outreach activities per year from the following list:


(i) Conduct social media campaign.


(ii) Conduct outreach via newspaper, television, or radio.


(iii) Contact organizations representing plumbers and contractors by mail to provide information about lead in drinking water including health effects, sources of lead, and the importance of using lead free plumbing materials.


(iv) Visit targeted customers to discuss the lead service line replacement program and opportunities for replacement.


(3) The water system may cease outreach activities when tap sampling shows that the 90th percentile for lead is at or below the trigger level of 10 µg/L for two consecutive tap sampling monitoring periods or when all customer-side lead or galvanized requiring replacement service line owners refuse to participate in the lead service line replacement program. For purposes of this paragraph (h)(3), a refusal includes a signed statement by the customer refusing lead service line replacement, or documentation by the water system of a verbal refusal or of no response after two good faith attempts to reach the customer.


(i) Public education to local and State health agencies—(1) Find-and-fix results. All community water systems must provide information to local and State health agencies about find-and-fix activities conducted in accordance with § 141.82(j) including the location of the tap sample site that exceeded 15 µg/L, the result of the initial tap sample, the result of the follow up tap sample, the result of water quality parameter monitoring, and any distribution system management actions or corrosion control treatment adjustments made.


(2) Timing and content. Community water systems must annually send copies of the public education materials provided under paragraph (a) of this section, and of paragraph (h)(1) of this section for actions conducted in the previous calendar year no later than July 1 of the following year.


(3) Delivery. Community water systems shall send public education materials and find-and-fix information to local and State health agencies by mail or by another method approved by the State.


(j) Public education requirements for small water system compliance flexibility POU devices—(1) Content. All small community water systems and non-transient non-community water systems that elect to implement POU devices under § 141.93 must provide public education materials to inform users how to properly use POU devices to maximize the units’ effectiveness in reducing lead levels in drinking water.


(2) Timing. Water systems shall provide the public education materials at the time of POU device delivery.


(3) Delivery. Water systems shall provide the public education materials in person, by mail, or by another method approved by the State, to persons at locations where the system has delivered POU devices.


[72 FR 57815, Oct. 10, 2007, as amended at 86 FR 4294, Jan. 15, 2021]


§ 141.86 Monitoring requirements for lead and copper in tap water.

(a) Sample site location. (1) By the applicable date for commencement of monitoring under paragraph (d)(1) of this section, each water system shall identify a pool of targeted sampling sites based on the service line inventory conducted in accordance with § 141.84(a), that meet the requirements of this section, and which is sufficiently large enough to ensure that the water system can collect the number of lead and copper tap samples required in paragraph (c) of this section. Sampling sites may not include sites with installed point-of-entry (POE) treatment devices and taps used at sampling sites may not have point-of-use (POU) devices designed to remove inorganic contaminants, except for water systems monitoring under § 141.93(a)(3)(iv) and water systems using these devices for the primary drinking water tap to meet other primary and secondary drinking water standards and all service connections have POEs or POUs to provide localized treatment for compliance with the other drinking water standards. Lead and copper sampling results for systems monitoring under § 141.93(a)(3)(iv) may not be used for the purposes of meeting the criteria for reduced monitoring specified in paragraph (d)(4) of this section.


(2) A water system must use the information on lead, copper, and galvanized iron or steel that is required to be identified under § 141.42(d) when conducting a materials evaluation and the information on lead service lines that is required to be collected under § 141.84(a) to identify potential lead service line sampling sites.


(3) The sampling sites for a community water system’s sampling pool must consist of single-family structures that are served by a lead service line (“Tier 1 sampling sites”). When multiple-family residences comprise at least 20 percent of the structures served by the water system, the system may include these types of structures in its Tier 1 sampling pool, if served by a lead service line. Sites with lead status unknown service lines must not be used as Tier 1 sampling sites.


(4) A community water system with insufficient Tier 1 sampling sites must complete its sampling pool with “Tier 2 sampling sites,” consisting of buildings, including multiple-family residences that are served by a lead service line. Sites with lead status unknown service lines must not be used as Tier 2 sampling sites.


(5) A community water system with insufficient Tier 1 and Tier 2 sampling sites must complete its sampling pool with “Tier 3 sampling sites,” consisting of single-family structures that contain galvanized lines identified as being downstream of a lead service line (LSL) currently or in the past, or known to be downstream of a lead gooseneck, pigtail or connector. Sites with lead status unknown service lines must not be used as Tier 3 sampling sites.


(6) A community water system with insufficient Tier 1, Tier 2, and Tier 3 sampling sites must complete its sampling pool with “Tier 4 sampling sites,” consisting of single-family structures that contain copper pipes with lead solder installed before the effective date of the State’s applicable lead ban. Sites with lead status unknown service lines must not be used as Tier 4 sampling sites.


(7) A community water system with insufficient Tier 1, Tier 2, Tier 3, and Tier 4 sampling sites must complete its sampling pool with “Tier 5 sampling sites,” consisting of single-family structures or buildings, including multiple family residences that are representative of sites throughout the distribution system. For the purpose of this paragraph (a)(7), a representative site is a site in which the plumbing materials used at that site would be commonly found at other sites served by the water system. Water systems may use non-residential buildings that are representative of sites throughout the distribution system if and only if there are an insufficient number of single-family or multiple family residential Tier 5 sites available.


(8) The sampling sites selected for a non-transient non-community water system must consist of sites that are served by a lead service line (“Tier 1 sampling sites”). Sites with lead status unknown service lines must not be used as Tier 1 sampling sites.


(9) A non-transient non-community water system with insufficient Tier 1 sites complete its sampling pool with “Tier 3 sampling sites,” consisting of sampling sites that contain galvanized lines identified as being downstream of an LSL currently or in the past, or known to be downstream of a lead gooseneck, pigtail, or connector. Sites with lead status unknown service lines must not be used as Tier 3 sampling sites.


(10) A non-transient non-community water system with insufficient Tier 1 and Tier 3 sampling sites must complete its sampling pool with “Tier 5 sampling sites,” consisting of sampling sites that are representative of sites throughout the distribution system. For the purpose of this paragraph (a)(10), a representative site is a site in which the plumbing materials used at that site would be commonly found at other sites served by the water system.


(11) A water system whose distribution system contains lead service lines must collect all samples for monitoring under this section from sites served by a lead service line. A water system that cannot identify a sufficient number of sampling sites served by lead service lines must still collect samples from every site served by a lead service line, and collect the remaining samples in accordance with tiering requirements under paragraphs (a)(5) through (7) or paragraphs (a)(9) through (10) of this section.


(b) Sample collection methods. (1) All tap samples for lead and copper collected in accordance with this subpart, with the exception of fifth liter samples collected under paragraph (b)(3) of this section, and samples collected under paragraphs (b)(5) and (h) of this section, must be first draw samples. The first draw sample shall be analyzed for lead and copper in tap sampling periods where both contaminants are required to be monitored. In tap sampling periods where only lead is required to be monitored, the first draw sample may be analyzed for lead only.


(2) Each first draw tap sample for lead and copper must be one liter in volume and have stood motionless in the plumbing system of each sampling site for at least six hours. Bottles used to collect first draw samples must be wide-mouth one-liter sample bottles. First draw samples from residential housing must be collected from the cold-water kitchen or bathroom sink tap. First draw samples from a nonresidential building must be one liter in volume and collected at a tap from which water is typically drawn for consumption. State-approved non-first-draw samples collected in lieu of first draw samples pursuant to paragraph (b)(5) of this section must be one liter in volume and shall be collected at an interior tap from which water is typically drawn for First draw samples may be collected by the system or the system may allow residents to collect first draw samples after instructing the residents of the sampling procedures specified in this paragraph (b)(2). Sampling instructions provided to residents must not include instructions for aerator removal and cleaning or flushing of taps prior to the start of the minimum six-hour stagnation period. To avoid problems of residents handling nitric acid, acidification of first draw samples may be done up to 14 days after the sample is collected. After acidification to resolubilize the metals, the sample must stand in the original container for the time specified in the approved EPA method before the sample can be analyzed. If a system allows residents to perform sampling, the system may not challenge, based on alleged errors in sample collection, the accuracy of sampling results.


(3)(i) All tap samples for copper collected in at sites with a lead service line shall be the first draw sample collected using the procedure listed in this paragraph (b)(3). Tap samples for copper are required to be collected and analyzed only in monitoring periods for which copper monitoring is required.


(ii) Systems must collect tap water in five consecutively numbered one-liter sample bottles after the water has stood motionless in the plumbing of each sampling site for at least six hours without flushing the tap prior to sample collection. Systems must analyze first draw samples for copper, when applicable, and fifth liter samples for lead. Bottles used to collect these samples must be wide-mouth one-liter sample bottles. Systems must collect first draw samples in the first sample bottle with each subsequently numbered bottle being filled until the final bottle is filled with the water running constantly during sample collection. Fifth liter sample is the final sample collected in this sequence. System must collect first draw and fifth liter samples from residential housing from the cold-water kitchen or bathroom sink tap First draw and fifth liter samples from a nonresidential building must be one liter in volume and collected at an interior cold water tap from which water is typically drawn for consumption. First draw and fifth liter samples may be collected by the system or the system may allow residents to collect first draw samples and fifth liter samples after instructing the residents on the sampling procedures specified in this paragraph (b)(3)(ii). Sampling instructions provided to customers must not direct the customer to remove the aerator or clean or flush the taps prior to the start of the minimum six-hour stagnation period. To avoid problems of residents handling nitric acid, the system may acidify first draw samples up to 14 days after the sample is collected. After acidification to resolubilize the metals, the sample must stand in the original container for the time specified in the approved EPA method before the sample can be analyzed. If a system allows residents to perform sampling, the system may not challenge, based on alleged errors in sample collection, the accuracy of sampling results.


(4) A water system must collect each first draw tap sample from the same sampling site from which it collected the previous sample. A water system must collect each fifth liter sample from the same sampling site from which it collected the previous sample. If, for reasons beyond the control of the water system, the water system cannot gain entry to a sampling site in order to collect a follow-up tap sample, the system may collect the follow-up tap sample from another sampling site in its sampling pool as long as the new site meets the same targeting criteria, and is within reasonable proximity of the original site.


(5) A non-transient, non-community water system, or a community water system that meets the criteria of § 141.85(b)(7), that does not have enough taps that can supply first draw samples or fifth liter samples meeting the six-hour minimum stagnation time, as defined in § 141.2, may apply to the State in writing to substitute non-first draw, first-draw, or fifth liter samples that do not meet the six-hour minimum stagnation time. Such systems must collect as many first draw or fifth liter samples from interior taps typically used for consumption, as possible and must identify sampling times and locations that would likely result in the longest standing time for the remaining sites. The State has the discretion to waive the requirement for prior State approval of sites not meeting the six-hour stagnation time either through State regulation or written notification to the system.


(c) Number of samples. Water systems shall collect at least one sample during each monitoring period specified in paragraph (d) of this section from the number of sites listed in the first column (“standard monitoring”) of the table in this paragraph. A system conducting reduced monitoring under paragraph (d)(4) of this section shall collect at least one sample from the number of sites specified in the second column (“reduced monitoring”) of the table in this paragraph during each monitoring period specified in paragraph (d)(4) of this section. Such reduced monitoring sites shall be representative of the sites required for standard monitoring. A public water system that has fewer than five drinking water taps, that can be used for human consumption meeting the sample site criteria of paragraph (a) of this section to reach the required number of sample sites listed in paragraph (c) of this section, must collect at least one sample from each tap and then must collect additional samples from those taps on different days during the monitoring period to meet the required number of sites. Alternatively the State may allow these public water systems to collect a number of samples less than the number of sites specified in paragraph (c) of this section, provided that 100 percent of all taps that can be used for human consumption are sampled. The State must approve this reduction of the minimum number of samples in writing based on a request from the system or onsite verification by the State. States may specify sampling locations when a system is conducting reduced monitoring. The table is as follows:


System size (number of people served)
Number of sites (standard

monitoring)
Number of sites (reduced

monitoring)
>100,00010050
10,001 to 100,0006030
3,301 to 10,0004020
501 to 3,3002010
101 to 500105
≤10055

(d) Timing of monitoring—(1) Standard monitoring. Standard monitoring is a six-month tap sampling monitoring period that begins on January 1 or July 1 of the year in which the water system is monitoring at the standard number of sites in accordance to paragraph (c) of this section.


(i) All water systems with lead service lines, including those deemed optimized under § 141.81(b)(3), and systems that did not conduct monitoring that meets all requirements of this section (e.g., sites selected in accordance with paragraph (a) of this section, samples collected in accordance with paragraph (b) of this section, etc.) between January 15, 2021, and October 16, 2024, must begin the first standard monitoring period on January 1 or July 1 in the year following October 16, 2024, whichever is sooner. Upon completion of this monitoring, systems must monitor in accordance with paragraph (d)(1)(ii) of this section.


(ii) Systems that conducted monitoring that meets all requirements of this section (e.g., sites selected in accordance with paragraph (a) of this section, samples collected in accordance with paragraph (b) of this section, etc.) between January 15, 2021, and October 16, 2024, and systems that have completed monitoring under paragraph (d)(1)(i) of this section, must continue monitoring as follows:


(A) Systems that do not meet the criteria under paragraph (d)(4) of the section must conduct standard monitoring.


(B) Systems that meet the criteria under paragraph (d)(4) of this section must continue to monitor in accordance with the criteria in paragraph (d)(4).


(C) Any system monitoring at a reduced frequency in accordance with paragraph (d)(4) of this section that exceeds an action level must resume standard monitoring beginning January 1 of the calendar year following the tap sampling monitoring period in which the system exceeded the action level. Any such system must also monitor in accordance with § 141.87(b), (c), or (d) as applicable.


(D) Any system monitoring at a reduced frequency that exceeds the lead trigger level but meets the copper action level must not monitor any less frequently than annually and must collect samples from the standard number of sites as established in paragraph (c) of this section. This monitoring must begin the calendar year following the tap sampling monitoring period in which the system exceeded the action level. Any such system must also monitor in accordance with § 141.87(b), (c), or (d) as applicable.


(E) Any system that fails to operate at or above the minimum value or within the range of values for the water quality parameters specified by the State under § 141.82(f) for more than nine days in any monitoring period specified in § 141.87 must conduct standard tap water monitoring and must resume sampling for water quality parameters in accordance with § 141.87(d). This standard monitoring must begin no later than the 6-month period beginning January 1 of the calendar year following the water quality parameter excursion.


(F) Any water system that becomes a large water system without corrosion control treatment or any large water system without corrosion control treatment whose lead 90th percentile exceeds the lead practical quantitation level must conduct standard monitoring for at least two consecutive 6-month tap sampling monitoring periods and then must continue monitoring in accordance with this paragraph (d)(1)(ii)(F).


(2) Monitoring after installation of initial or re-optimized corrosion control treatment, installation of source water treatment and addition of new source or change in treatment. (i) Any water system that installs or re-optimizes corrosion control treatment, as a result of exceeding the lead or copper action level, must monitor for lead and copper every six months and comply with previously designated water quality parameter values, where applicable, until the State specifies new water quality parameter values for optimal corrosion control.


(ii) Any water system that re-optimizes corrosion control treatment as a result of exceeding the lead trigger level but has not exceeded the lead or copper action level must monitor annually for lead at the standard number of sites listed in paragraph (c) of this section. Samples shall be analyzed for copper on a triennial basis. Small and medium-size systems that do not exceed the lead trigger level in three annual monitoring periods may reduce lead monitoring in accordance with paragraph (d)(4) of this section.


(iii) Any water system that installs source water treatment pursuant to § 141.83(a)(3) must monitor every six months until the system at or below lead and copper action levels for two consecutive six-month monitoring periods. Systems that do not exceed the lead or copper action level for two consecutive 6-month monitoring periods may reduce monitoring in accordance with paragraph (d)(4) of this section.


(iv) If a water system has notified the State in writing in accordance with § 141.90(a)(3) of an upcoming addition of a new source or long term change in treatment, the water system shall monitor every six months at the standard number of sites listed under paragraph (c) of this section until the system is at or below the lead and copper action levels for two consecutive six-month monitoring periods, unless the State determines that the addition of the new source or long term change in treatment is not significant and, therefore, does not warrant more frequent monitoring. Systems that do not exceed the lead and copper action levels, and/or the lead trigger level for two consecutive six-month monitoring periods may reduce monitoring in accordance with paragraph (d)(4) of this section.


(3) Monitoring after State specifies water quality parameter values for optimal corrosion control treatment. (i) After the State specifies the values for water quality control parameters under § 141.82(f), the system must conduct standard six-month monitoring for two consecutive six-month tap sampling monitoring periods. Systems may then reduce monitoring in accordance with paragraph (d)(4) of this section as applicable, following a State determination that reduced monitoring is approved.


(ii) Systems required to complete the re-optimization steps in § 141.81(d) due to the exceedance of the lead trigger level that do not exceed the lead and copper action levels must monitor for two consecutive 6-month tap sampling monitoring periods. Systems may then reduce monitoring in accordance with paragraph (d)(4) of this section as applicable following a State determination that reduced monitoring is approved.


(4) Reduced monitoring based on 90th percentile levels. Reduced monitoring refers to an annual or triennial tap sampling monitoring period. The reduced monitoring frequency is based on the 90th percentile value for the water system.


(i) A water system that meets the criteria for reduced monitoring under paragraph (d)(4) of this section must collect these samples from sampling sites identified in paragraph (a) of this section. Systems monitoring annually or less frequently must conduct the lead and copper tap sampling during the months of June, July, August, or September unless the State has approved a different sampling period in accordance with paragraph (d)(4)(i)(A) of this section.


(A) The State at its discretion may approve a different tap sampling period for conducting the lead and copper tap sampling for systems collecting samples at a reduced frequency. Such a period must be no longer than four consecutive months, within one calendar year, and must represent a time of normal operation where the highest levels of lead are most likely to occur. For a non-transient non-community water system that does not operate during the months of June through September and for which the period of normal operation where the highest levels of lead are most likely to occur is not known, the State must designate a period that represents normal operation for the system. This monitoring must begin during the period approved or designated by the State in the calendar year immediately following the end of the second 6-month monitoring period for systems initiating annual monitoring and during the 3-year period following the end of the third consecutive year of annual monitoring for systems initiating triennial monitoring.


(B) Systems monitoring annually that have been collecting samples during the months of June through September and that receive State approval to alter their tap sampling monitoring period under paragraph (d)(4)(i)(A) of this section must collect their next round of samples during a time period that ends no later than 21 months after the previous round of sampling. Systems monitoring triennially that have been collecting samples during the month of June through September and receive State approval to alter their sampling collection period as per paragraph (d)(4)(i)(A) of this section must collect their next round of samples during a time period that ends no later than 45 months after the previous tap sampling period. Subsequent monitoring must be conducted annually or triennially, as required by this section.


(C) Small systems with waivers granted pursuant to paragraph (g) of this section that have been collecting samples during the months of June through September and receive State approval to alter their tap sampling period as per paragraph (d)(4)(i)(A) of this section must collect their next round of samples before the end of the 9-year period.


(ii) Any system that meets the lead trigger level and the copper action levels during two consecutive 6-month tap sampling monitoring periods may reduce the monitoring frequency to annual monitoring and must sample at the standard number of sampling sites for lead and the reduced number of sites for copper as specified in paragraph (c) of this section. Systems operating OCCT must also have maintained the range of OWQPs set by the State in accordance with § 141.82(f) for the same period and receive a written determination from the State approving annual monitoring based on the State’s review of monitoring, treatment, and other relevant information submitted by the system as required by § 141.90. This sampling must begin no later than the calendar year immediately following the last calendar year in which the system sampled.


(iii) Any water system that exceeds the lead trigger level but not the lead and copper action levels during two consecutive 6-month tap sampling monitoring periods must monitor no less frequently than annually at the standard number of sampling sites for lead and copper specified in paragraph (c) of this section. Systems operating OCCT must also have maintained the range of OWQPs set by the State in accordance with § 141.82(f) for the same period of 6-month monitoring and receive a written determination from the State approving annual monitoring based on the State’s review of monitoring, treatment, and other relevant information submitted by the system as required by § 141.90. This sampling must begin no later than the calendar year immediately following the last calendar year in which the system sampled.


(iv) Any water system that exceeds the lead trigger level but not the lead and copper action levels during three consecutive years of monitoring may reduce the tap sampling monitoring period for copper to once every three years; however, the system may not reduce the tap sampling monitoring period for lead. Systems operating OCCT must also maintain the range of OWQPs set by the State in accordance with § 141.82(f) and receive a written determination from the State approving triennial monitoring based on the State’s review of monitoring, treatment, and other relevant information submitted by the system as required by § 141.90. This sampling must begin no later than the third calendar year immediately following the last calendar year in which the system sampled.


(v) Any small or medium-sized system that does not exceed the lead trigger level and the copper action level during three consecutive years of monitoring (standard monitoring completed during both six-month periods of a calendar year shall be considered 1 year of monitoring) may sample at the reduced number of sites for lead and copper in accordance with paragraph (c) of this section and reduce the monitoring frequency to triennial monitoring. Systems operating OCCT must also have maintained the range of OWQPs set by the State in accordance with § 141.82(f) for the same three-year period and receive a written determination from the State approving triennial monitoring based on the State’s review of monitoring, treatment, and other relevant information submitted by the system as required by § 141.90. This sampling must begin no later than three calendar years after the last calendar year in which the system sampled.


(vi) Any water system that demonstrates for two consecutive 6-month monitoring periods that its 90th percentile lead level, calculated under § 141.80(c)(4), is less than or equal to 0.005 mg/L and the 90th percentile copper level, calculated under § 141.80(c)(4), is less than or equal to 0.65 mg/L may sample at the reduced number of sites for lead and copper in accordance with paragraph (c) of this section and reduce the frequency of monitoring to triennial monitoring. For water systems with corrosion control treatment, the system must maintain the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the State under § 141.82(f) to qualify for reduced monitoring pursuant to this paragraph (d)(4)(vi).


(e) Additional monitoring by systems. The results of any monitoring conducted in addition to the minimum requirements of this section (such as customer-requested sampling) shall be considered by the water system and the State in making any determinations (i.e., calculating the 90th percentile lead or copper level) under this subpart. Lead service line water systems that are unable to collect the minimum number of samples from Tier 1 or Tier 2 sites shall calculate the 90th percentile using data from all the lead service lines sites and the highest lead and copper values from lower tier sites to meet the specified minimum number of samples. Systems must submit data from additional tier 3, 4 or 5 sites to the State but may not use these results in the 90th percentile calculation. Water systems must include customer-requested samples from known lead service line sites in the 90th percentile calculation if the samples meet the requirements of this section.


(f) Invalidation of lead and copper tap samples used in the calculation of the 90th percentile. A sample invalidated under this paragraph (f) does not count toward determining lead or copper 90th percentile levels under § 141.80(c)(4) or toward meeting the minimum monitoring requirements of paragraph (c) of this section.


(1) The State may invalidate a lead or copper tap water sample at least if one of the following conditions is met.


(i) The laboratory establishes that improper sample analysis caused erroneous results.


(ii) The State determines that the sample was taken from a site that did not meet the site selection criteria of this section.


(iii) The sample container was damaged in transit.


(iv) There is substantial reason to believe that the sample was subject to tampering.


(2) The system must report the results of all samples to the State and all supporting documentation for samples the system believes should be invalidated.


(3) To invalidate a sample under paragraph (f)(1) of this section, the decision and the rationale for the decision must be documented in writing. States may not invalidate a sample solely on the grounds that a follow-up sample result is higher or lower than that of the original sample.


(4) The water system must collect replacement samples for any samples invalidated under this section if, after the invalidation of one or more samples, the system has too few samples to meet the minimum requirements of paragraph (c) of this section. Any such replacement samples must be taken as soon as possible, but no later than 20 days after the date the State invalidates the sample or by the end of the applicable monitoring period, whichever occurs later. Replacement samples taken after the end of the applicable monitoring period shall not also be used to meet the monitoring requirements of a subsequent monitoring period. The replacement samples shall be taken at the same locations as the invalidated samples or, if that is not possible, at locations other than those already used for sampling during the monitoring period.


(g) Monitoring waivers for systems serving 3,300 or fewer persons. Any water system serving 3,300 or fewer persons that meets the criteria of this paragraph (g) may apply to the State to reduce the frequency of monitoring for lead and copper under this section to once every nine years (i.e., a “full waiver”) if it meets all of the materials criteria specified in paragraph (g)(1) of this section and all of the monitoring criteria specified in paragraph (g)(2) of this section. If State regulations permit, any water system serving 3,300 or fewer persons that meets the criteria in paragraphs (g)(1) and (2) of this section only for lead, or only for copper, may apply to the State for a waiver to reduce the frequency of tap water monitoring to once every nine years for that contaminant only (i.e., a “partial waiver”).


(1) Materials criteria. The system must demonstrate that its distribution system and service lines and all drinking water supply plumbing, including plumbing conveying drinking water within all residences and buildings connected to the system, are free of lead-containing materials and/or copper-containing materials, as those terms are defined in this paragraph, as follows:


(i) Lead. To qualify for a full waiver, or a waiver of the tap water monitoring requirements for lead (i.e., a “lead waiver”), the water system must provide certification and supporting documentation to the State that the system is free of all lead-containing materials, as follows:


(A) It contains no plastic pipes which contain lead plasticizers, or plastic service lines which contain lead plasticizers; and


(B) It is free of lead service lines, lead pipes, lead soldered pipe joints, and leaded brass or bronze alloy fittings and fixtures, unless such fittings and fixtures meet the specifications of any standard established pursuant to 42 U.S.C. 300g-6(e) (SDWA section 1417(e)).


(ii) Copper. To qualify for a full waiver, or a waiver of the tap water monitoring requirements for copper (i.e., a “copper waiver”), the water system must provide certification and supporting documentation to the State that the system contains no copper pipes or copper service lines.


(2) Monitoring criteria for waiver issuance. The system must have completed at least one 6-month round of standard tap water monitoring for lead and copper at sites approved by the State and from the number of sites required by paragraph (c) of this section and demonstrate that the 90th percentile levels for any and all rounds of monitoring conducted since the system became free of all lead-containing and/or copper-containing materials, as appropriate, meet the following criteria.


(i) Lead levels. To qualify for a full waiver, or a lead waiver, the system must demonstrate that the 90th percentile lead level does not exceed 0.005 mg/L.


(ii) Copper levels. To qualify for a full waiver, or a copper waiver, the system must demonstrate that the 90th percentile copper level does not exceed 0.65 mg/L.


(3) State approval of waiver application. The State shall notify the system of its waiver determination, in writing, setting forth the basis of its decision and any condition of the waiver. As a condition of the waiver, the State may require the system to perform specific activities (e.g., limited monitoring, periodic outreach to customers to remind them to avoid installation of materials that might void the waiver) to avoid the risk of lead or copper concentration of concern in tap water. The small system must continue monitoring for lead and copper at the tap as required by paragraphs (d)(1) through (d)(4) of this section, as appropriate, until it receives written notification from the State that the waiver has been approved.


(4) Monitoring frequency for systems with waivers. (i) A system with a full waiver must conduct tap water monitoring for lead and copper in accordance with paragraph (d)(4)(iv) of this section at the reduced number of sampling sites identified in paragraph (c) of this section at least once every nine years and provide the materials certification specified in paragraph (g)(1) of this section for both lead and copper to the State along with the monitoring results. Samples collected every nine years shall be collected no later than every ninth calendar year.


(ii) A system with a partial waiver must conduct tap water monitoring for the waived contaminant in accordance with paragraph (d)(4)(iv) of this section at the reduced number of sampling sites specified in paragraph (c) of this section at least once every nine years and provide the materials certification specified in paragraph (g)(1) of this section pertaining to the waived contaminant along with the monitoring results. Such a system also must continue to monitor for the non-waived contaminant in accordance with requirements of paragraph (d)(1) through (d)(4) of this section, as appropriate.


(iii) Any water system with a full or partial waiver shall notify the State in writing in accordance with § 141.90(a)(3) of any upcoming long-term change in treatment or addition of a new source, as described in that section. The State must review and approve the addition of a new source or long-term change in water treatment before it is implemented by the water system. The State has the authority to require the system to add or modify waiver conditions (e.g., require recertification that the system is free of lead-containing and/or copper-containing materials, require additional round(s) of monitoring), if it deems such modifications are necessary to address treatment or source water changes at the system.


(iv) If a system with a full or partial waiver becomes aware that it is no longer free of lead-containing or copper-containing materials, as appropriate, (e.g., as a result of new construction or repairs), the system shall notify the State in writing no later than 60 days after becoming aware of such a change.


(5) Continued eligibility. If the system continues to satisfy the requirements of paragraph (g)(4) of this section, the waiver will be renewed automatically, unless any of the conditions listed in paragraph (g)(5)(i) through (g)(5)(iii) of this section occurs. A system whose waiver has been revoked may re-apply for a waiver at such time as it again meets the appropriate materials and monitoring criteria of paragraphs (g)(1) and (g)(2) of this section.


(i) A system with a full waiver or a lead waiver no longer satisfies the materials criteria of paragraph (g)(1)(i) of this section or has a 90th percentile lead level greater than 0.005 mg/L.


(ii) A system with a full waiver or a copper waiver no longer satisfies the materials criteria of paragraph (g)(1)(ii) of this section or has a 90th percentile copper level greater than 0.65 mg/L.


(iii) The State notifies the system, in writing, that the waiver has been revoked, setting forth the basis of its decision.


(6) Requirements following waiver revocation. A system whose full or partial waiver has been revoked by the State is subject to the corrosion control treatment and lead and copper tap water monitoring requirements, as follows:


(i) If the system exceeds the lead and/or copper action level, the system must implement corrosion control treatment in accordance with the deadlines specified in § 141.81(e), and any other applicable requirements of this subpart.


(ii) If the system meets both the lead and the copper action level, the system must monitor for lead and copper at the tap no less frequently than once every three years using the reduced number of sample sites specified in paragraph (c) of this section.


(7) Pre-existing waivers. Small system waivers approved by the State in writing prior to April 11, 2000 shall remain in effect under the following conditions:


(i) If the system has demonstrated that it is both free of lead-containing and copper-containing materials, as required by paragraph (g)(1) of this section and that its 90th percentile lead levels and 90th percentile copper levels meet the criteria of paragraph (g)(2) of this section, the waiver remains in effect so long as the system continues to meet the waiver eligibility criteria of paragraph (g)(5) of this section. The first round of tap water monitoring conducted pursuant to paragraph (g)(4) of this section shall be completed no later than nine years after the last time the system has monitored for lead and copper at the tap.


(ii) If the system has met the materials criteria of paragraph (g)(1) of this section but has not met the monitoring criteria of paragraph (g)(2) of this section, the system shall conduct a round of monitoring for lead and copper at the tap demonstrating that it meets the criteria of paragraph (g)(2) of this section no later than September 30, 2000. Thereafter, the waiver shall remain in effect as long as the system meets the continued eligibility criteria of paragraph (g)(5) of this section. The first round of tap water monitoring conducted pursuant to paragraph (g)(4) of this section shall be completed no later than nine years after the round of monitoring conducted pursuant to paragraph (g)(2) of this section.


(h) Follow-up samples for “find-and-fix” under § 141.82(j). Systems shall collect a follow-up sample at any site that exceeds the action level within 30 days of receiving the sample results. These follow-up samples may use different sample volumes or different sample collection procedures to assess the source of elevated lead. Systems shall submit samples collected under this section to the State but shall not include such samples in the 90th percentile calculation.


(i) Public availability of tap monitoring results used in the 90th percentile calculation. All water systems must make available to the public the results of compliance tap water monitoring data, including data used in the 90th percentile calculation under § 141.80(c)(4), within 60 days of the end of the applicable tap sampling period. Nothing in this section requires water systems to make publicly available the addresses of the sites where the tap samples were collected. Large systems shall make available the monitoring results in a digital format. Small and medium-size systems shall make available the monitoring results in either a written or digital format. Water systems shall retain tap sampling monitoring data in accordance to recordkeeping requirements under § 141.91.


[56 FR 26548, June 7, 1991; 56 FR 32113, July 15, 1991; 57 FR 28788, June 29, 1992, as amended at 65 FR 2007, Jan. 12, 2000; 72 FR 57817, Oct. 10, 2007; 86 FR 4296, Jan. 15, 2021; 86 FR 31947, June 16, 2021]


§ 141.87 Monitoring requirements for water quality parameters.

All large water systems, and all small- and medium-size water systems that exceed the lead or copper action level, and all small- and medium-size water systems with corrosion control treatment that exceed the lead trigger level must monitor water quality parameters in addition to lead and copper in accordance with this section.


(a) General requirements—(1) Sample collection methods. (i) Tap samples must be representative of water quality throughout the distribution system, taking into account the number of persons served, the different sources of water, the different treatment methods employed by the system, and seasonal variability. Tap sampling under this section is not required to be conducted at taps targeted for lead and copper sampling under § 141.86(a). Sites selected for tap samples under this section must be included in the site sample plan specified under § 141.86(a)(1). The site sample plan must be updated prior to changes to the sampling locations. [Note: Systems may find it convenient to conduct tap sampling for water quality parameters at sites used for total coliform sampling under § 141.21(a)(1) if they also meet the requirements of this section.]


(ii) Samples collected at the entry point(s) to the distribution system must be from locations representative of each source after treatment. If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water is representative of all sources being used).


(2) Number of samples. (i) Systems must collect two tap samples for applicable water quality parameters during each monitoring period specified under paragraphs (b) through (e) of this section from the minimum number of sites listed in table 1 to this paragraph (a)(2)(i). Systems that add sites as a result of the “find-and-fix” requirements in § 141.82(j) must collect tap samples for applicable water quality parameters during each monitoring period under paragraphs (b) through (e) of this section and must sample from that adjusted minimum number of sites. Systems are not required to add sites if they are monitoring at least twice the minimum number of sites list in table 1 to this paragraph (a)(2)(i).


Table 1 to paragraph (a)(2)(i)

System size (number people served)
Minimum number of sites for water quality parameters
>100,00025
10,001-100,00010
3,301-10,0003
501-3,3002
101-5001
≤ 1001

(ii)(A) Except as provided in paragraph (c)(2) of this section, water systems without corrosion control treatment must collect two samples for each applicable water quality parameter at each entry point to the distribution system during each monitoring period specified in paragraph (b) of this section. During each monitoring period specified in paragraphs (c) through (e) of this section, water systems must collect one sample for each applicable water quality parameter at each entry point to the distribution system.


(B) During each monitoring period specified in paragraphs (c) through (e) of the section, water systems with corrosion control treatment must continue to collect one sample for each applicable water quality parameter at each entry point to the distribution system no less frequently than once every two weeks.


(b) Initial sampling for water systems. Any large water system without corrosion control treatment must monitor for water quality parameters as specified in paragraphs (b)(1) and (2) of this section during the first two six-month tap sampling monitoring periods beginning no later than January 1 of the calendar year after the system either becomes a large water system, or fails to maintain their 90th percentile for lead below the PQL for lead. Any medium or small system that exceeds the lead or copper action level and any system with corrosion control treatment for which the State has not designated OWQPs that exceeds the lead trigger level shall monitor for water quality parameters as specified in paragraphs (b)(1) and (2) of this section for two consecutive 6-month periods beginning the month immediately following the end of the tap sampling period in which the exceedance occurred.


(1) At taps, two samples for:


(i) pH;


(ii) Alkalinity;


(2) At each entry point to the distribution system all of the applicable parameters listed in paragraph (b)(1) of this section.


(c) Monitoring after installation of optimal corrosion control or re-optimized corrosion control treatment. (1) Any system that installs or modifies corrosion control treatment pursuant to § 141.81(d)(5) or (e)(5) and is required to monitor pursuant § 141.81(d)(6) or (e)(6) must monitor the parameters identified in paragraphs (c)(1)(i) and (ii) of this section every six months at the locations and frequencies specified in paragraphs (c)(1)(i) and (ii) of this section until the State specifies new water quality parameter values for optimal corrosion control pursuant to paragraph (d) of this section. Water systems must collect these samples evenly throughout the 6-month monitoring period so as to reflect seasonal variability.


(i) At taps, two samples each for:


(A) pH;


(B) Alkalinity;


(C) Orthophosphate, when an inhibitor containing an orthophosphate compound is used;


(D) Silica, when an inhibitor containing a silicate compound is used.


(ii) Except as provided in paragraph (c)(1)(iii) of this section, at each entry point to the distribution system, at least one sample no less frequently than every two weeks (biweekly) for:


(A) pH;


(B) When alkalinity is adjusted as part of optimal corrosion control, a reading of the dosage rate of the chemical used to adjust alkalinity, and the alkalinity concentration; and


(C) When a corrosion inhibitor is used as part of optimal corrosion control, a reading of the dosage rate of the inhibitor used, and the concentration of orthophosphate or silica (whichever is applicable).


(iii) Any groundwater system can limit entry point sampling described in paragraph (c)(1)(ii) of this section to those entry points that are representative of water quality and treatment conditions throughout the system. If water from untreated groundwater sources mixes with water from treated groundwater sources, the system must monitor for water quality parameters both at representative entry points receiving treatment and representative entry points receiving no treatment. Prior to the start of any monitoring under this paragraph (c)(1)(iii), the water system must provide to the State, written information identifying the selected entry points and documentation, including information on seasonal variability, sufficient to demonstrate that the sites are representative of water quality and treatment conditions throughout the system.


(2) States have the discretion to require small and medium-size systems with treatment for which the State has not designated OWQPs that exceed the lead trigger level but not the lead and copper action levels to conduct water quality parameter monitoring as described in paragraph (c)(1) of this section or the State can develop its own water quality control parameter monitoring structure for these systems.


(d) Monitoring after State specifies water quality parameter values for optimal corrosion control. (1) After the State specifies the values for applicable water quality parameters reflecting optimal corrosion control treatment under § 141.82(f), systems must monitor for the specified optimal water quality parameters during 6-month periods that begin on either January 1 or July 1. Such monitoring must be spaced evenly throughout the 6-month monitoring period so as to reflect seasonal variability and be consistent with the structure specified in paragraphs (c)(1)(i) through (iii) of this section.


(i) All large systems must measure the applicable water quality parameters specified by the State and determine compliance with the requirements of § 141.82(g) every six months with the first 6-month period to begin on either January 1 or July 1, whichever comes first, after the State specifies the optimal values under § 141.82(f).


(ii) Any small or medium-size water system that exceeds an action level must begin monitoring during the six-month period immediately following the tap sampling monitoring period in which the exceedance occurs and continue monitoring until the water system no longer exceeds the lead and copper action levels and meets the optimal water quality control parameters in two consecutive 6-month tap sampling monitoring periods under § 141.86(d)(3). For any such small and medium-size system that is subject to a reduced monitoring frequency pursuant to § 141.86(d)(4) at the time of the action level exceedance, the start of the applicable 6-month monitoring period under this paragraph must coincide with the start of the applicable tap sampling monitoring period under § 141.86(d)(4).


(iii) Compliance with State-designated optimal water quality parameter values must be determined as specified under § 141.82(g).


(2) Any small or medium-size system that exceeds the lead trigger level, but not the lead and copper action levels for which the State has set optimal water quality control parameters must monitor as specified in paragraph (d)(1) of this section every six month, until the system no longer exceeds the lead trigger level in two consecutive tap sampling monitoring periods.


(3) States have the discretion to continue to require systems described in paragraph (d)(2) of this section to monitor optimal water quality control parameters.


(e) Reduced monitoring. (1) Any large water system that maintains the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the State under § 141.82(f) and does not exceed the lead trigger level during each of two consecutive 6-month monitoring periods under paragraph (d) of this section must continue monitoring at the entry point(s) to the distribution system as specified in paragraph (c)(1)(ii) of this section. Such system may collect two tap samples for applicable water quality parameters from the following reduced number of sites during each 6-month monitoring period. Water systems must collect these samples evenly throughout the 6-month monitoring period so as to reflect seasonal variability.


Table 2 to paragraph (e)(1)

System size (number of people served)
Reduced minimum number of sites for water quality parameters
>100,00010
10,001-100,0007
3,301-10,0003
501-3,3002
101-5001
≤1001

(2)(i) Any water system that maintains the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the State under § 141.82(f) and does not exceed the lead trigger level or copper action level during three consecutive years of monitoring may reduce the frequency with which it collects the number of tap samples for applicable water quality parameters specified in paragraph (e)(1) of this section, from every six months to annually. This sampling begins during the calendar year immediately following the end of the monitoring period in which the third consecutive year of 6-month monitoring occurs.


(ii) A water system may reduce the frequency with which it collects tap samples for applicable water quality parameters specified in paragraph (e)(1) of this section to every year if it demonstrates during two consecutive monitoring periods that its tap water lead level at the 90th percentile is less than or equal to the PQL for lead of 0.005 mg/L that its tap water copper level at the 90th percentile is less than or equal to 0.65 mg/L in § 141.80(c)(3), and that it also has maintained the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the State under § 141.82(f).


(3) A water system that conducts sampling annually must collect these samples evenly throughout the year so as to reflect seasonal variability.


(4) Any water system subject to the reduced monitoring frequency that fails to operate at or above the minimum value or within the range of values for the water quality parameters specified by the State in § 141.82(f) for more than nine days in any 6-month period specified in § 141.82(g) must resume distribution system tap water sampling in accordance with the number and frequency requirements in paragraph (d) of this section. Such a system may resume annual monitoring for water quality parameters at the tap at the reduced number of sites specified in paragraph (e)(1) of this section after it has completed two subsequent consecutive 6-month rounds of monitoring that meet the criteria of paragraph (e)(1) of this section and/or may resume annual monitoring for water quality parameters at the tap at the reduced number of sites after it demonstrates through subsequent rounds of monitoring that it meets the criteria of either paragraph (e)(2)(i) or (ii) of this section.


(f) Additional monitoring by systems. The results of any monitoring conducted in addition to the minimum requirements of this section must be considered by the water system and the State in making any determinations (i.e., determining concentrations of water quality parameters) under this section or § 141.82.


(g) Additional sites added from find-and-fix. Any water system that conducts water quality parameter monitoring at additional sites through the “find-and-fix” provisions pursuant to § 141.82(j) must add those sites to the minimum number of sites specified under paragraphs (a) through (e) of this section unless the system is monitoring at least twice the minimum number of sites.


[86 FR 4300, Jan. 15, 2021]


§ 141.88 Monitoring requirements for lead and copper in source water.

(a) Sample location, collection methods, and number of samples. (1) A water system that fails to meet the lead or copper action level on the basis of tap samples collected in accordance with § 141.86 shall collect lead and copper source water samples in accordance with the following requirements regarding sample location, number of samples, and collection methods:


(i) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the distribution system at a point which is representative of each source after treatment (hereafter called a sampling point). The system shall take one sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.


(ii) Surface water systems shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the distribution system at a point which is representative of each source after treatment (hereafter called a sampling point). The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.



Note to paragraph (a)(1)(ii):

For the purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.


(iii) If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water is representative of all sources being used).


(iv) The State may reduce the total number of samples which must be analyzed by allowing the use of compositing. Compositing of samples must be done by certified laboratory personnel. Composite samples from a maximum of five samples are allowed, provided that if the lead concentration in the composite sample is greater than or equal to 0.001 mg/L or the copper concentration is greater than or equal to 0.160 mg/L, then either:


(A) A follow-up sample shall be taken and analyzed within 14 days at each sampling point included in the composite; or


(B) If duplicates of or sufficient quantities from the original samples from each sampling point used in the composite are available, the system may use these instead of resampling.


(2) Where the results of sampling indicate an exceedance of maximum permissible source water levels established under § 141.83(b)(4), the State may require that one additional sample be collected as soon as possible after the initial sample was taken (but not to exceed two weeks) at the same sampling point. If a State-required confirmation sample is taken for lead or copper, then the results of the initial and confirmation sample shall be averaged in determining compliance with the State-specified maximum permissible levels. Any sample value below the detection limit shall be considered to be zero. Any value above the detection limit but below the PQL shall either be considered as the measured value or be considered one-half the PQL.


(b) Monitoring frequency after system exceeds tap water action level. Any system which exceeds the lead or copper action level at the tap for the first time or for the first time after an addition of a new source or installation of source water treatment required under § 141.83(b)(2) shall collect one source water sample from each entry point to the distribution system no later than six months after the end of the tap sampling period during which the lead or copper action level was exceeded. For tap sampling periods that are annual or less frequent, the end of the tap sampling period is September 30 of the calendar year in which the sampling occurs, or if the State has established an alternate monitoring period, the last day of that period. If the State determines that source water treatment is not required under § 141.83(b)(2), the state may waive source water monitoring, for any subsequent lead or copper action level exceedance at the tap, in accordance with the requirements in paragraphs (b)(1)(i) through (iii) of this section.


(1) The State may waive source water monitoring for lead or copper action level exceedance at the tap under the following conditions:


(i) The water system has already conducted source water monitoring following a previous action level exceedance;


(ii) The State has determined that source water treatment is not required; and


(iii) The system has not added any new water sources.


(2) [Reserved]


(c) Monitoring frequency after installation of source water treatment and addition of new source. (1) Any system which installs source water treatment pursuant to § 141.83(a)(3) shall collect one source water sample from each entry point to the distribution system during two consecutive six-month monitoring periods by the deadline specified in § 141.83(a)(4).


(2) Any system which adds a new source shall collect one source water sample from each entry point to the distribution system until the system demonstrates that finished drinking water entering the distribution system has been maintained below the maximum permissible lead and copper concentrations specified by the State in § 141.83(b)(4) or the State determines that source water treatment is not needed.


(d) Monitoring frequency after State specifies maximum permissible source water levels. (1) A system shall monitor at the frequency specified in paragraphs (d)(1) and (2) of this section, in cases where the State specifies maximum permissible source water levels under § 141.83(b)(4).


(i) A water system using only groundwater shall collect samples once during the three-year compliance period (as that term is defined in § 141.2) in effect when the applicable State determination under paragraph (d)(1) of this section is made. Such systems shall collect samples once during each subsequent compliance period. Triennial samples shall be collected every third calendar year.


(ii) A water system using surface water (or a combination of surface and ground water) shall collect samples once during each calendar year, the first annual monitoring period to begin during the year in which the applicable State determination is made under paragraph (d)(1) of this section.


(2) A system is not required to conduct source water sampling for lead and/or copper if the system meets the action level for the specific contaminant in tap water samples during the entire source water sampling period applicable to the system under paragraph (d)(1) (i) or (ii) of this section.


(e) Reduced monitoring frequency. (1) A water system using only groundwater may reduce the monitoring frequency for lead and copper in source water to once during each nine-year compliance cycle (as that term is defined in § 141.2) provided that the samples are collected no later than every ninth calendar year and if the system meets the following criteria:


(i) The system demonstrates that finished drinking water entering the distribution system has been maintained below the maximum permissible lead and copper concentrations specified by the State in § 141.83(b)(4) during at least three consecutive monitoring periods under paragraph (d)(1) of this section.


(ii) [Reserved]


(2) A water system using surface water (or a combination of surface water and groundwater) may reduce the monitoring frequency in paragraph (d)(1) of this section to once during each nine-year compliance cycle (as that term is defined in § 141.2) provided that the samples are collected no later than every ninth calendar year and if the system meets the following criteria:


(i) The system demonstrates that finished drinking water entering the distribution system has been maintained below the maximum permissible lead and copper concentrations specified by the State in § 141.83(b)(4) for at least three consecutive years’


(ii) [Reserved]


(3) A water system that uses a new source of water is not eligible for reduced monitoring for lead and/or copper until concentrations in samples collected from the new source during three consecutive monitoring periods are below the maximum permissible lead and copper concentrations specified by the State in § 141.83(a)(5).


[56 FR 26548, June 7, 1991; 57 FR 28788 and 28789, June 29, 1992, as amended at 65 FR 2012, Jan. 12, 2000; 72 FR 57819, Oct. 10, 2007; 86 FR 4302, Jan. 15, 2021]


§ 141.89 Analytical methods.

(a) Analyses for lead, copper, pH, alkalinity, orthophosphate, and silica shall be conducted in accordance with methods in § 141.23(k)(1).


(1) Analyses for alkalinity, orthophosphate, pH, and silica may be performed by any person acceptable to the State. Analyses under this section for lead and copper shall only be conducted by laboratories that have been certified by EPA or the State. To obtain certification to conduct analyses for lead and copper, laboratories must:


(i) Analyze Performance Evaluation samples, which include lead and copper, provided by or acceptable to EPA or the State at least once a year by each method for which the laboratory desires certification; and


(ii) Achieve quantitative acceptance limits as follows:


(A) For lead: ±30 percent of the actual amount in the Performance Evaluation sample when the actual amount is greater than or equal to 0.005 mg/L. The Practical Quantitation Level, or PQL for lead is 0.005 mg/L.


(B) For Copper: ±10 percent of the actual amount in the Performance Evaluation sample when the actual amount is greater than or equal to 0.050 mg/L. The Practical Quantitation Level, or PQL for copper is 0.050 mg/L.


(iii) Achieve method detection limit for lead of 0.001 mg/L according to the procedures in appendix B of part 136 of this title.


(iv) Be currently certified by EPA or the State to perform analyses to the specifications described in paragraph (a)(1) of this section.


(2) States have the authority to allow the use of previously collected monitoring data for purposes of monitoring, if the data were collected and analyzed in accordance with the requirements of this subpart.


(3) All lead and copper levels measured between the PQL and MDL must be either reported as measured or they can be reported as one-half the PQL specified for lead and copper in paragraph (a)(1)(ii) of this section. All levels below the lead and copper MDLs must be reported as zero.


(4) All copper levels measured between the PQL and the MDL must be either reported as measured or they can be reported as one-half the PQL (0.025 mg/L). All levels below the copper MDL must be reported as zero.


(b) [Reserved]


[56 FR 26548, June 7, 1991, as amended at 57 FR 28789, June 29, 1992; 57 FR 31847, July 17, 1992; 59 FR 33863, June 30, 1994; 59 FR 62470, Dec. 5, 1994; 64 FR 67466, Dec. 1, 1999; 65 FR 2012, Jan. 12, 2000; 72 FR 57819, Oct. 10, 2007; 86 FR 4303, Jan. 15, 2021]


§ 141.90 Reporting requirements.

All water systems shall report all of the following information to the State in accordance with this section.


(a) Reporting requirements for tap water monitoring for lead and copper and for water quality parameter monitoring. (1) Notwithstanding the requirements of § 141.31(a), except as provided in paragraph (a)(1)(viii) of this section, a water system must report the information specified in paragraphs (a)(1)(i) through (ix) of this section, for all tap water samples specified in § 141.86 and for all water quality parameter samples specified in § 141.87 within the first 10 days following the end of each applicable tap sampling monitoring period specified in §§ 141.86 and 141.87 (i.e., every six months, annually, every three years, or every nine years). For tap sampling periods with a duration less than six months, the end of the tap sampling monitoring period is the last date samples can be collected during that tap sampling period as specified in §§ 141.86 and 141.87.


(i) The results of all tap samples for lead and copper including the location of each site and the site selection criteria under § 141.86(a)(3) through (10), used as the basis for which the site was selected for the water system’s sampling pool, accounting for § 141.86(a)(11);


(ii) Documentation for each tap water lead or copper sample for which the water system requests invalidation pursuant to § 141.86(f)(2);


(iii) Water systems with lead service lines, galvanized service lines requiring replacement, or lead status unknown service lines in the lead service line inventory conducted under § 141.84(a) must re-evaluate the tap sampling locations used in their sampling pool prior to the compliance date specified in § 141.80(a) and thereafter prior to the next round of tap sampling conducted by the system, or annually, whichever is more frequent.


(A) By the start of the first applicable tap sampling monitoring period in § 141.86(d), the water system must submit a site sample plan to the State in accordance with § 141.86, including a list of tap sample site locations identified from the inventory in § 141.84(a), and a list a tap sampling WQP sites selected under 141.87(a)(1). The site sample plan must be updated and submitted to the State prior to any changes to sample site locations. The State may require modifications to the site sample plan as necessary.


(B) For lead service line systems with insufficient lead service line sites to meet the minimum number required in § 141.86, documentation in support of the conclusion that there are an insufficient number of lead service line sites meeting the criteria under § 141.86(a)(3) or (4) for community water systems or § 141.86(a)(8) for non-transient, non-community water systems, as applicable;


(iv) The 90th percentile lead and copper concentrations measured from among all lead and copper tap water samples collected during each tap sampling period (calculated in accordance with § 141.80(c)(4)), unless the State calculates the water system’s 90th percentile lead and copper levels under paragraph (h) of this section;


(v) With the exception of initial tap sampling conducted pursuant to § 141.86(d)(1)(i), the water system must identify any site which was not sampled during previous tap sampling periods, and include an explanation of why sampling sites have changed;


(vi) The results of all water quality parameter tap samples that are required to be collected under § 141.87(b) through (g);


(vii) The results of all samples collected at the entry point(s) to the distribution system for applicable water quality parameters under § 141.87 (b)-(e);


(viii) A water system shall report the results of all water quality parameter samples collected under § 141.87(c) through (f) during each six-month monitoring period specified in § 141.87(d) within the first 10 days following the end of the monitoring period unless the State has specified a more frequent reporting requirement;


(ix) By the start of the first applicable tap sampling period in § 141.86(d), the water system must submit to the State, a copy of the tap sampling protocol that is provided to individuals who are sampling. The State shall verify that wide-mouth collection bottles are used and recommendations for pre-stagnation flushing and aerator cleaning or removal prior to sample collection are not included pursuant to § 141.86(b). The tap sampling protocol shall contain instructions for correctly collecting a first draw sample for sites without lead service lines and a first draw and a fifth liter sample for sites with lead service lines, where applicable. If the water system seeks to modify its tap sampling protocol specified in this paragraph (a)(1)(ix), it must submit the updated version of the protocol to the State for review and approval no later than 60 days prior to use.


(2) For a non-transient non-community water system, or a community water system meeting the criteria of § 141.86(b)(5), that does not have enough taps that can provide first draw or fifth liter samples, the water system must either:


(i) Provide written documentation to the State identifying standing times and locations for enough non-first-draw and fifth liter samples to make up its sampling pool under § 141.86(b)(5) by the start of the first applicable monitoring period under § 141.86(d) unless the State has waived prior State approval of non-first-draw and fifth liter sample sites selected by the water system pursuant to § 141.86(b)(5); or


(ii) If the State has waived prior approval of non-first-draw sample sites selected by the system, identify, in writing, each site that did not meet the six-hour minimum standing time and the length of standing time for that particular substitute sample collected pursuant to § 141.86(b)(5) and include this information with the lead and copper tap sample results required to be submitted pursuant to paragraph (a)(1)(i) of this section.


(3) At a time specified by the State, or if no specific time is designated by the State, as early as possible but no later than six months prior to the addition of a new source or any long-term change in water treatment, a water system must submit written documentation to the State describing the addition. The State must review and approve the addition of a new source or long-term treatment change before it is implemented by the water system. The State may require the system to take actions before or after the addition of a new source or long-term treatment change to ensure the system will operate and maintain optimal corrosion control treatment such as additional water quality parameter monitoring, additional lead or copper tap sampling, and re-evaluation of corrosion control treatment. Examples of long-term treatment changes include but are not limited to, the addition of a new treatment process or modification of an existing treatment process. Examples of modifications include switching secondary disinfectants, switching coagulants (e.g., alum to ferric chloride), and switching corrosion inhibitor products (e.g., orthophosphate to blended phosphate). Long-term changes can also include dose changes to existing chemicals if the water system is planning long-term changes to its finished water pH or residual inhibitor concentration. Long-term treatment changes would not include chemical dose fluctuations associated with daily raw water quality changes where a new source has not been added.


(4) Any small system applying for a monitoring waiver under § 141.86(g), or subject to a waiver granted pursuant to § 141.86(g)(3), shall provide the following information to the State in writing by the specified deadline:


(i) By the start of the first applicable tap sampling monitoring period in § 141.86(d), any small water system applying for a monitoring waiver shall provide the documentation required to demonstrate that it meets the waiver criteria of § 141.86(g)(1) and (2).


(ii) No later than nine years after the monitoring previously conducted pursuant to § 141.86(g)(2) or § 141.86(g)(4)(i), each small system desiring to maintain its monitoring waiver shall provide the information required by §§ 141.86(g)(4)(i) and (ii).


(iii) No later than 60 days after it becomes aware that it is no longer free of lead-containing and/or copper-containing material, as appropriate, each small system with a monitoring waiver shall provide written notification to the State, setting forth the circumstances resulting in the lead-containing and/or copper-containing materials being introduced into the system and what corrective action, if any, the system plans to remove these materials.


(5) Each ground water system that limits water quality parameter monitoring to a subset of entry points under § 141.87(c)(3) shall provide, by the commencement of such monitoring, written correspondence to the State that identifies the selected entry points and includes information sufficient to demonstrate that the sites are representative of water quality and treatment conditions throughout the system.


(b) Source water monitoring reporting requirements. (1) A water system shall report the sampling results for all source water samples collected in accordance with § 141.88 within the first 10 days following the end of each source water monitoring period (i.e., annually, per compliance period, per compliance cycle) specified in § 141.88.


(2) With the exception of the first round of source water sampling conducted pursuant to § 141.88(b), the system shall specify any site which was not sampled during previous monitoring periods, and include an explanation of why the sampling point has changed.


(c) Corrosion control treatment reporting requirements. By the applicable dates under § 141.81, systems shall report the following information:


(1) For water systems demonstrating that they have already optimized corrosion control, information required in § 141.81(b)(1) through (3).


(2) For systems required to optimize corrosion control, their recommendation regarding optimal corrosion control treatment under § 141.82(a).


(3) For systems required to evaluate the effectiveness of corrosion control treatments under § 141.82(c), the information required by that paragraph.


(4) For systems required to install optimal corrosion control designated by the State under § 141.82(d), a letter certifying that the system has completed installing that treatment.


(d) Source water treatment reporting requirements. By the applicable dates in § 141.83, systems shall provide the following information to the State:


(1) If required under § 141.83(b)(1), their recommendation regarding source water treatment;


(2) For systems required to install source water treatment under § 141.83(b)(2), a letter certifying that the system has completed installing the treatment designated by the State within 24 months after the State designated the treatment.


(e) Lead service line inventory and replacement reporting requirements. Water systems must report the following information to the State to demonstrate compliance with the requirements of §§ 141.84 and 141.85:


(1) No later than October 16, 2024, the water system must submit to the State an inventory of service lines as required in § 141.84(a).


(2) No later than October 16, 2024, any water system that has inventoried a lead service line, galvanized requiring replacement, or lead status unknown service line in its distribution system must submit to the State, as specified in § 141.84(b), a lead service line replacement plan.


(3) The water system must provide the State with updated versions of its inventory as required in § 141.84(a) in accordance with its tap sampling monitoring period schedule as required in § 141.86(d), but no more frequently than annually. The updated inventory must be submitted within 30 days of the end of each tap sampling monitoring period.


(i) When the water system has demonstrated that it has no lead, galvanized requiring replacement, or lead status unknown service lines in its inventory, it is no longer required to submit inventory updates to the State, except as required in paragraph (e)(3)(ii) of this section.


(ii) In the case that a water system meeting the requirements of paragraph (e)(3)(i) of this section, subsequently discovers any service lines requiring replacement in its distribution system, it must notify the State within 30 days of identifying the service line(s) and prepare an updated inventory in accordance with § 141.84(a) on a schedule established by the State.


(4) Within 30 days of the end of each tap sampling monitoring period, the water system must certify that it conducted replacement of any encountered lead goosenecks, pigtails, and connectors in accordance with § 141.84(c).


(5) Within 30 days of the end of each tap sampling monitoring period, the water system must certify to the State that any partial and full lead service line replacements were conducted in accordance with § 141.84(d) and (e), respectively.


(6) If the water system fails to meet the 45-day deadline to complete a customer-initiated lead service line replacement pursuant to § 141.84(d)(4), it must notify the State within 30 days of the replacement deadline to request an extension of the deadline up to 180 days of the customer-initiated lead service line replacement.


(i) The water system must certify annually that it has completed all customer-initiated lead service line replacements in accordance with § 141.84(d)(4).


(ii) [Reserved]


(7) No later than 30 days after the end of the water system’s annual lead service line replacement requirements under § 141.84(f) and (g), the water system must submit the following information to the State, and continue to submit it each year it conducts lead service line replacement under § 141.84(f) and (g):


(i) The number of lead service lines in the initial inventory;


(ii) The number of galvanized requiring replacement service lines in the initial inventory;


(iii) The number of lead status unknown service lines in the inventory at the onset of the water system’s annual lead service line replacement program;


(iv) The number of full lead service lines that have been replaced and the address associated with each replaced service line;


(v) The number of galvanized requiring replacement service lines that have been replaced and the address associated with each replaced service line;


(vi) The number of lead status unknown service lines remaining in the inventory;


(vii) The total number of lead status unknown service lines determined to be non-lead; and


(viii) The total number of service lines initially inventoried as “non-lead” later discovered to be a lead service line or a galvanized requiring replacement service line.


(8) No later than 30 days after the end of each tap sampling period, any water system that has received customer refusals about lead service line replacements or customer non-responses after a minimum of two good faith efforts by the water system to contact customers regarding full lead service line replacements in accordance with § 141.84(g)(7), must certify to the State the number of customer refusals or non-responses it received from customers served by a lead service line or galvanized requiring replacement service line, and maintain such documentation.


(9) No later than 12 months after the end of a tap sampling period in which a water system exceeds the lead action level in sampling conducted pursuant to § 141.86, the system must provide to the State its schedule for annually replacing an average annual rate, calculated on a two year rolling basis, of at least three percent, or otherwise specified in § 141.84(g)(9), of the number of known lead service lines and galvanized lines requiring replacement when the lead trigger or action level was first exceeded and lead status unknown service lines at the beginning of each year that required replacement occurs in its distribution system.


(10) No later than 12 months after the end of a sampling period in which a system exceeds the lead trigger level in sampling conducted pursuant to § 141.86, and every 12 months thereafter, the system shall certify to the State in writing that the system has:


(i) Conducted consumer notification as specified in §§ 141.84(f)(4) and 141.85(g) and


(ii) Delivered public education materials to the affected consumers as specified in § 141.85(a).


(iii) A water system that does not meet its annual service line replacement goal as required under § 141.84(f) must certify to the State in writing that the water system has conducted public outreach as specified in § 141.85(h). The water system must also submit the outreach materials used to the State.


(11) The annual submission to the State under paragraph (e)(10) of this section must contain the following information:


(i) The certification that results of samples collected between three months and six months after the date of a full or partial lead service line replacement were provided to the resident in accordance with the timeframes in § 141.85(d)(2). Mailed notices post-marked within three business days of receiving the results shall be considered “on time.”


(ii) [Reserved]


(12) Any system which collects samples following a partial lead service line replacement required by § 141.84 must report the results to the State within the first ten days of the month following the month in which the system receives the laboratory results, or as specified by the State. States, at their discretion may eliminate this requirement to report these monitoring results, but water systems shall still retain such records. Systems must also report any additional information as specified by the State, and in a time and manner prescribed by the State, to verify that all partial lead service line replacement activities have taken place.


(13) Any system with lead service lines in its inventory must certify on an annual basis that the system has complied with the consumer notification of lead service line materials as specified in § 141.85(e).


(f) Public education program reporting requirements. (1) Any water system that is subject to the public education requirements in § 141.85 shall, within ten days after the end of each period in which the system is required to perform public education in accordance with § 141.85(b), send written documentation to the State that contains:


(i) The public education materials that were delivered, and a demonstration that the water system has delivered the public education materials that meet the content requirements in § 141.85(a) and the delivery requirements in § 141.85(b); and


(ii) A list of all the newspapers, radio stations, television stations, and facilities and organizations to which the system delivered public education materials during the period in which the system was required to perform public education tasks.


(2) Unless required by the State, a system that previously has submitted the information required by paragraph (f)(1)(ii) of this section need not resubmit the information required by paragraph (f)(1)(ii) of this section, as long as there have been no changes in the distribution list and the system certifies that the public education materials were distributed to the same list submitted previously.


(3) No later than three months following the end of the tap sampling period, each water system must mail a sample copy of the consumer notification of tap results to the State along with a certification that the notification has been distributed in a manner consistent with the requirements of § 141.85(d).


(4) Annually by July 1, the water system must demonstrate to the State that it delivered annual consumer notification and delivered lead service line information materials to affected consumers with a lead, galvanized requiring replacement, or lead status unknown service line in accordance with § 141.85(e) for the previous calendar year. The water system shall also provide a copy of the notification and information materials to the State.


(5) Annually by July 1, the water system must demonstrate to the State that it conducted an outreach activity in accordance with § 141.85(h) when failing to meet the lead service line replacement goal as specified in § 141.84(f) for the previous calendar year. The water system shall also submit a copy to the State of the outreach provided.


(6) Annually, by July 1, the water system must certify to the State that it delivered notification to affected customers after any lead service line disturbance in accordance with § 141.85(f) for the previous calendar year. The water system shall also submit a copy of the notification to the State.


(7) Annually, by July 1, the water system must certify to the State that it delivered the required find-and-fix information to the State and local health departments for the previous calendar year.


(g) Reporting of additional monitoring data. Any water system which collects more samples than the minimum required, shall report the results to the State within the first 10 days following the end of the applicable monitoring period under §§ 141.86, 141.87, and 141.88 during which the samples are collected. This includes the monitoring data pertaining to “find-and-fix” pursuant to §§ 141.86(h) and 141.87(g). The system must certify to the State the number of customer refusals or non-responses for follow-up sampling under § 141.82(j) it received and information pertaining to the accuracy of the refusals or non-responses, within the first 10 days following the end of the applicable tap sampling period in which an individual sample exceeded the action level.


(h) Reporting of 90th percentile lead and copper concentrations where the State calculates a water system’s 90th percentile concentrations. A water system is not required to report the 90th percentile lead and copper concentrations measured from among all lead and copper tap water samples collected during each tap sampling monitoring period, as required by paragraph (a)(1)(iv) of this section if:


(1) The State has previously notified the water system that it will calculate the water system’s 90th percentile lead and copper concentrations, based on the lead and copper tap results submitted pursuant to paragraph (h)(2)(i) of this section, and the water system provides the results of lead and copper tap water samples no later than 10 days after the end of the applicable tap sampling monitoring period;


(2) The system has provided the following information to the State by the date specified in paragraph (h)(1) of this section:


(i) The results of all tap samples for lead and copper including the location of each site and the criteria under § 141.86(a)(3) through (10) under which the site was selected for the water system’s sampling pool; and


(ii) An identification of sampling sites utilized during the current tap sampling monitoring period that were not sampled during previous monitoring periods, and an explanation of why sampling sites have changed; and


(3) The State has provided the results of the 90th percentile lead and copper calculations, in writing, to the water system within 15 days of the end of the tap sampling period.


(i) Reporting requirements for a community water system’s public education and sampling in schools and child care facilities. (1) A community water system shall send a report to the State by July 1 of each year for the previous calendar year’s activity. The report must include the following:


(i) Certification that the water system made a good faith effort to identify schools and child care facilities in accordance with § 141.92(e). The good faith effort may include reviewing customer records and requesting lists of schools and child care facilities from the primacy agency or other licensing agency. A water system that certifies that no schools or child care facilities are served by the water system is not required to include information in paragraphs (i)(1)(ii) through (iv) of this section in the report. If there are changes to schools and child care facilities that a water system serves, an updated list must be submitted at least once every five years in accordance with § 141.92(e).


(ii) Certification that the water system has delivered information about health risks from lead in drinking water to the school and child care facilities that they serve in accordance with § 141.92(a)(2) and (g)(1).


(iii) Certification that the water system has completed the notification and sampling requirements of § 141.92 and paragraphs (i)(1)(iii)(A) through (E) of this section at a minimum of 20 percent of elementary schools and 20 percent of child care facilities. Certification that the water system has completed the notification and sampling requirements of § 141.92(g) and paragraphs (i)(1)(iii)(A), (B), and (E) of this section for any secondary school(s) sampled. After a water system has successfully completed one cycle of required sampling in all elementary schools and child care facilities identified in § 141.92(a)(1), it shall certify completion of the notification and sampling requirements of § 141.92(g) and paragraphs (i)(1)(iii)(A), (B), and (E) of this section for all sampling completed in any school or child care facility, thereafter.


(A) The number of schools and child care facilities served by the water system;


(B) The number of schools and child care facilities sampled in the calendar year;


(C) The number of schools and child care facilities that have refused sampling;


(D) Information pertaining to outreach attempts for sampling that were declined by the school or child care facility; and


(E) The analytical results for all schools and child care facilities sampled by the water system in the calendar year.


(iv) Certification that sampling results were provided to schools, child care facilities, and local and State health departments.


(2) [Reserved]


(3) The State has provided the results of the 90th percentile lead and copper calculations, in writing, to the water system before the end of the monitoring period.


(j) Reporting requirements for small system compliance flexibility options. By the applicable dates provided in paragraphs (j)(1) and (2), water systems implementing requirements pursuant to § 141.93, shall provide the following information to the State:


(1) Small water systems and non-transient, non-community water systems implementing the point-of-use device option under § 141.93(a)(3), shall report the results from the tap sampling required under § 141.93 no later than 10 days after the end of the tap sampling monitoring period. If the trigger level is exceeded, the water system must reach out to the homeowner and/or building management within 24 hours of receiving the tap sample results. The corrective action must be completed within 30 days. If the corrective action is not completed within 30 days, the system must provide documentation to the State within 30 days explaining why it was unable to correct the issue. Water systems selecting the point-of-use device option under § 141.93(a)(3) shall provide documentation to certify maintenance of the point-of-use devices unless the State waives the requirement of this paragraph (j)(1).


(2) Small community water systems and non-transient, non-community water systems implementing the small system compliance flexibility option to replace all lead-bearing plumbing under § 141.93(a)(4) must provide certification to the State that all lead-bearing material has been replaced on the schedule established by the State, within one year of designation of the option under § 141.93(a)(4).


[56 FR 26548, June 7, 1991; 57 FR 28789, June 29, 1992, as amended at 59 FR 33864, June 30, 1994; 65 FR 2012, Jan. 12, 2000; 72 FR 57819, Oct. 10, 2007; 86 FR 4303, Jan. 15, 2021; 86 FR 31947, June 16, 2021]


§ 141.91 Recordkeeping requirements.

Any system subject to the requirements of this subpart shall retain on its premises original records of all sampling data and analyses, reports, surveys, letters, evaluations, schedules, State determinations, and any other information required by §§ 141.81 through 141.88, 141.90, 141.92, and 141.93. Each water system shall retain the records required by this section for no fewer than 12 years.


[86 FR 4306, Jan. 15, 2021]


§ 141.92 Monitoring for lead in schools and child care facilities.

All community water systems must conduct directed public education and lead monitoring at the schools and child care facilities they serve if those schools or child care facilities were constructed prior to January 1, 2014 or the date the State adopted standards that meet the definition of lead free in accordance with Section 1417 of the Safe Drinking Water Act, as amended by the Reduction of Lead in Drinking Water Act, whichever is earlier. Water systems must conduct lead sampling at elementary schools and child care facilities they serve once and on request of the facility thereafter. Water systems shall also conduct lead sampling at secondary schools they serve on request. The provisions of this section do not apply to a school or child care facility that is regulated as a public water system. The provisions in paragraph (a) of this section apply until a water system samples all the elementary schools and child care facilities they serve once as specified in paragraph (c) of this section. Thereafter, water systems shall follow the provisions as specified in paragraph (g) of this section.


(a) Public education to schools and child care facilities. (1) By the compliance date specified in § 141.80(a)(3), each water system must compile a list of schools and child care facilities served by the system.


(2) Each water system must contact elementary schools and child care facilities identified by the system in paragraph (a)(1) of this section to provide:


(i) Information about health risks from lead in drinking water on at least an annual basis consistent with the requirements of § 141.85(a);


(ii) Notification that the water system is required to sample for lead at elementary schools and child care facilities, including:


(A) A proposed schedule for sampling at the facility;


(B) Information about sampling for lead in schools and child care facilities (EPA’s 3Ts for Reducing Lead in Drinking Water Toolkit, EPA-815-B-18-007 or subsequent EPA guidance); and


(C) Instructions for identifying outlets for sampling and preparing for a sampling event 30 days prior to the event.


(3) The water system must include documentation in accordance with § 141.90(i) if an elementary school or child care facility is non-responsive or otherwise declines to participate in the monitoring or education requirements of this section. For the purposes of this section, a school or child care facility is non-responsive after the water system makes at least two separate good faith attempts to contact the facility to schedule sampling with no response.


(4) The water system must contact all secondary schools in paragraph (a)(1) of this section on at least an annual basis to provide information on health risks from lead in drinking water and how to request lead sampling as specified in paragraph (g)(1) of this section.


(b) Lead sampling in schools and child care facilities. (1) Five samples per school and two samples per child care facility at outlets typically used for consumption shall be collected. Except as provided in paragraphs (b)(1)(i) through (vi) of this section, the outlets shall not have point-of-use (POU) devices. The water system shall sample at the following locations:


(i) For schools: two drinking water fountains, one kitchen faucet used for food or drink preparation, one classroom faucet or other outlet used for drinking, and one nurse’s office faucet, as available.


(ii) For child care facilities: one drinking water fountain and one of either a kitchen faucet used for preparation of food or drink or one classroom faucet or other outlet used for drinking.


(iii) If any facility has fewer than the required number of outlets, the water system must sample all outlets used for consumption.


(iv) The water system may sample at outlets with POU devices if the facility has POU devices installed on all outlets typically used for consumption.


(v) If any facility does not contain the type of faucet listed above, the water system shall collect a sample from another outlet typically used for consumption as identified by the facility.


(vi) Water systems must collect the samples from the cold water tap subject to the following additional requirements:


(A) Each sample for lead shall be a first draw sample;


(B) The sample must be 250 ml in volume;


(C) The water must have remained stationary in the plumbing system of the sampling site (building) for at least 8 but no more than 18 hours; and


(D) Samples must be analyzed using acidification and the corresponding analytical methods in § 141.89.


(2) The water system, school or child care facility, or other appropriately trained individual may collect samples in accordance with paragraph (b)(1) of this section.


(c) Frequency of sampling at elementary schools and child care facilities. (1) Water systems shall collect samples from at least 20 percent of elementary schools served by the system and 20 percent of child care facilities served by the system per year, or according to a schedule approved by the State, until all schools and child care facilities identified under paragraph (a)(1) of this section have been sampled or have declined to participate. For the purposes of this section, a water system may count a refusal or non-response from an elementary school or child care facility as part of the minimum 20 percent per year.


(2) All elementary schools and child care facilities must be sampled at least once in the five years following the compliance date in § 141.80(a)(3).


(3) After a water system has completed one required cycle of sampling in all elementary schools and child care facilities, a water system must sample at the request of an elementary school or child care facility in accordance with paragraph (g) of this section.


(4) A water system must sample at the request of a secondary school as specified in paragraph (g) of this section. If a water system receives requests from more than 20 percent of secondary schools identified in paragraph (a)(1) of this section in any of the five years following the compliance date in § 141.80(a)(3), the water system may schedule the requests that exceed 20 percent for the following year and is not required to sample an individual secondary school more than once in the five year period.


(d) Alternative school and child care lead sampling programs. (1) If mandatory sampling for lead in drinking water is conducted for schools and child care facilities served by a community water system due to State or local law or program, the State may exempt the water system from the requirements of this section by issuing a written waiver:


(i) If the sampling is consistent with the requirements in paragraphs (b) and (c) of this section; or


(ii) If the sampling is consistent with the requirements in paragraphs (b)(1)(i) through (vi) and (c) of this section and it is coupled with any of the following remediation actions:


(A) Disconnection of affected fixtures;


(B) Replacement of affected fixtures with fixtures certified as lead free; and


(C) Installation of POU devices; or


(iii) If the sampling is conducted in schools and child care facilities served by the system less frequently than once every five years and it is coupled with any of the remediation actions specified in paragraph (d)(1)(ii) of this section; or


(iv) If the sampling is conducted under a grant awarded under Section 1464(d) of the SDWA, consistent with the requirements of the grant.


(2) The duration of the waiver may not exceed the time period covered by the mandatory or voluntary sampling and will automatically expire at the end of any 12-month period during which sampling is not conducted at the required number of schools or child care facilities.


(3) The State may issue a partial waiver to the water system if the sampling covers only a subset of the schools or child care facilities served by the system as designated under paragraph (a)(1) of this section.


(4) The State may issue a written waiver applicable to more than one system (e.g., one waiver for all systems subject to a statewide sampling program that meets the requirements of paragraph (d) of this section).


(e) Confirmation or revision of schools and child care facilities in inventory. A water system shall either confirm that there have been no changes to its list of schools and child care facilities served by the system developed pursuant to paragraph (a)(1) of this section, or submit a revised list at least once every five years.


(f) Notification of results. (1) A water system must provide analytical results as soon as practicable but no later than 30 days after receipt of the results to the school or child care facility, along with information about remediation options.


(2) A water system must provide analytical results annually to:


(i) The local and State health department; and


(ii) The State in accordance with § 141.90(i).


(g) Lead sampling in schools and child care facilities on request. (1) A water system must contact schools and child care facilities identified in paragraph (a)(1) of this section on at least an annual basis to provide:


(i) Information about health risks from lead in drinking water;


(ii) Information about how to request sampling for lead at the facility; and


(iii) Information about sampling for lead in schools and child care facilities (EPA’s 3Ts for Reducing Lead in Drinking Water Toolkit, EPA-815-B-18-007, or subsequent EPA guidance).


(2) A water system must conduct sampling as specified in paragraph (b) of this section when requested by the facility and provide:


(i) Instructions for identifying outlets for sampling and preparing for a sampling event at least 30 days prior to the event; and


(ii) Results as specified in paragraph (f) of this section.


(3) If a water system receives requests from more than 20 percent of the schools and child care facilities identified in paragraph (a)(1) of this section in a given year, the water system may schedule sampling for those that exceed 20 percent for the following year. A water system is not required to sample an individual school or child care facility more than once every five years.


(4) If voluntary sampling for lead in drinking water is conducted for schools and child care facilities served by a community water system that meets the requirements of this section, the State may exempt the water system from the requirements of this section by issuing a written waiver in accordance with paragraph (d) of this section.


Any system subject to the requirements of this subpart shall retain on its premises original records of all sampling data and analyses, reports, surveys, letters, evaluations, schedules, State determinations, and any other information required by §§ 141.81 through 141.88, 141.90, 141.92, and 141.93. Each water system shall retain the records required by this section for no fewer than 12 years.


[86 FR 4306, Jan. 15, 2021]


§ 141.93 Small water system compliance flexibility.

The compliance alternatives described in this section apply to small community water systems serving 10,000 or fewer persons and all non-transient, non-community water systems. Small community water systems and non-transient, non-community water systems with corrosion control treatment in place must continue to operate and maintain optimal corrosion control treatment until the State determines, in writing, that it is no longer necessary, and meet any requirements that the State determines to be appropriate before implementing a State approved compliance option described in this section.


(a) A small community water system and non-transient, non-community water systems that exceeds the lead trigger level but does not exceed the lead and copper action levels must collect water quality parameters in accordance with § 141.87(b) and evaluate compliance options in paragraphs (a)(1) through (4) of this section and make a compliance option recommendation to the State within six months of the end of the tap sampling period in which the exceedance occurred. The State must approve the recommendation or designate an alternative from compliance options in paragraphs (a)(1) through (4) of this section within six months of the recommendation by the water system. If the water system subsequently exceeds the lead action level it must implement the approved compliance option as specified in paragraph (b) of this section. Water systems must select from the following compliance options:


(1) Lead service line replacement. A water system must implement a full lead service line replacement program on a schedule approved by the State but not to exceed 15 years. A water system must begin lead service line replacement within one year after the State’s approval or designation of the compliance option.


(i) Lead service line replacement must be conducted in accordance with the requirements of § 141.84(e) and (g)(4), (8), and (9).


(ii) A water system must continue lead service line replacement even if the system’s 90th percentile lead level is at or below the action level in future tap sampling monitoring periods.


(iii) A water system must have no lead service lines, galvanized service lines requiring replacement, or “Lead status unknown” service lines in its inventory by the end of its lead service line replacement program.


(2) Corrosion control treatment. A water system must install and maintain optimal corrosion control treatment in accordance with §§ 141.81 and 141.82, even if its 90th percentile is at or below the action level in future tap sampling monitoring periods. Any water system that has corrosion control treatment installed must re-optimize its corrosion control treatment in accordance with § 141.81(d). Water systems required by the State to optimize or re-optimize corrosion control treatment must follow the schedules in § 141.81(d) or (e), beginning with Step 3 in paragraph (d)(3) or (e)(3) of § 141.81 unless the State specifies optimal corrosion control treatment pursuant to either § 141.81(d)(2)(ii) or (e)(2)(i) or (ii), as applicable.


(3) Point-of-use devices. A water system must install, maintain, and monitor POU devices in each household or building even if its 90th percentile is at or below the action level in future tap sampling monitoring periods.


(i)(A) A community water system must install a minimum of one POU device (at one tap) in every household and at every tap that is used for cooking and/or drinking in every non-residential building in its distribution system on a schedule specified by the State, but not to exceed one year.


(B) A non-transient, non-community water system must provide a POU device to every tap that is used for cooking and/or drinking on a schedule specified by the State, but not to exceed three months.


(ii) The POU device must be independently certified by a third party to meet the American National Standards Institute standard applicable to the specific type of POU unit to reduce lead in drinking water.


(iii) The POU device must be maintained by the water system according to manufacturer’s recommendations to ensure continued effective filtration, including but not limited to changing filter cartridges and resolving any operational issues. POU device must be equipped with mechanical warnings to ensure that customers are automatically notified of operational problems. The water system shall provide documentation to the state to certify maintenance of the point-of-use devices, unless the state waives this requirement, in accordance with § 141.90(j)(1).


(iv) The water system must monitor one-third of the POU devices each year and all POU devices must be monitored within a three-year cycle. First draw tap samples collected under this section must be taken after water passes through the POU device to assess its performance. Samples must be one-liter in volume and have had a minimum 6-hour stagnation time. All samples must be at or below the lead trigger level. The water systems must report the results from the tap sampling no later than 10 days after the end of the tap sampling monitoring period in accordance with § 141.90(j)(1). The system must document the problem and take corrective action at any site where the sample result exceeds the lead trigger level. If the trigger level is exceeded, the water system must reach out to the homeowner and/or building management no later than 24 hours of receiving the tap sample results. The corrective action must be completed within 30 days. If the corrective action is not completed within 30 days, the system must provide documentation to the State within 30 days explaining why it was unable to correct the issue.


(v) The water system must provide public education to consumers in accordance with § 141.85(j) to inform them on proper use of POU devices to maximize the units’ lead level reduction effectiveness.


(vi) The water system must operate and maintain the POU devices until the system receives State approval to select one of the other compliance flexibility options and implements it.


(4) Replacement of lead-bearing plumbing. A water system that has control over all plumbing in its buildings, and no unknown, galvanized, or lead service lines, must replace all plumbing that is not lead free in accordance with Section 1417 of the Safe Drinking Water Act, as amended by the Reduction of Lead in Drinking Water Act and any future amendments applicable at the time of replacement. The replacement of all lead-bearing plumbing must occur on a schedule established by the State but not to exceed one year. Water systems must provide certification to the State that all lead-bearing material has been replaced in accordance with § 141.90(j)(2).


(b)(1) A water system that exceeds the lead action level after exceeding the lead trigger level but does not exceed the copper action level must implement the compliance option approved by the State under paragraph (a) of this section.


(2) A water system that exceeds the lead action level, but has not previously exceeded the lead trigger level, and does not exceed the copper action level must complete the provisions in paragraph (a) of this section and must implement the compliance option approved by the State under paragraph (a) of this section.


(3) A water system that exceeds the trigger level after it has implemented a compliance option approved by the State under paragraph (a) of this section, must complete the steps in paragraph (a) and if it thereafter exceeds the action level, it must implement the compliance option approved by the State under paragraph (a) of this section.


[86 FR 4308, Jan. 15, 2021]


Subpart J—Use of Non-Centralized Treatment Devices


Source:52 FR 25716, July 8, 1987, unless otherwise noted.

§ 141.100 Criteria and procedures for public water systems using point-of-entry devices.

(a) Public water systems may use point-of-entry devices to comply with maximum contaminant levels only if they meet the requirements of this section.


(b) It is the responsibility of the public water system to operate and maintain the point-of-entry treatment system.


(c) The public water system must develop and obtain State approval for a monitoring plan before point-of-entry devices are installed for compliance. Under the plan approved by the State, point-of-entry devices must provide health protection equivalent to central water treatment. “Equivalent” means that the water would meet all national primary drinking water regulations and would be of acceptable quality similar to water distributed by a well-operated central treatment plant. In addition to the VOCs, monitoring must include physical measurements and observations such as total flow treated and mechanical condition of the treatment equipment.


(d) Effective technology must be properly applied under a plan approved by the State and the microbiological safety of the water must be maintained.


(1) The State must require adequate certification of performance, field testing, and, if not included in the certification process, a rigorous engineering design review of the point-of-entry devices.


(2) The design and application of the point-of-entry devices must consider the tendency for increase in heterotrophic bacteria concentrations in water treated with activated carbon. It may be necessary to use frequent backwashing, post-contactor disinfection, and Heterotrophic Plate Count monitoring to ensure that the microbiological safety of the water is not compromised.


(e) All consumers shall be protected. Every building connected to the system must have a point-of-entry device installed, maintained, and adequately monitored. The State must be assured that every building is subject to treatment and monitoring, and that the rights and responsibilities of the public water system customer convey with title upon sale of property.


[52 FR 25716, July 8, 1987; 53 FR 25111, July 1, 1988]


§ 141.101 Use of bottled water.

Public water systems shall not use bottled water to achieve compliance with an MCL. Bottled water may be used on a temporary basis to avoid unreasonable risk to health.


[63 FR 31934, June 11, 1998]


Subpart K—Treatment Techniques


Source:56 FR 3594, Jan. 30, 1991, unless otherwise noted.

§ 141.110 General requirements.

The requirements of subpart K of this part constitute national primary drinking water regulations. These regulations establish treatment techniques in lieu of maximum contaminant levels for specified contaminants.


§ 141.111 Treatment techniques for acrylamide and epichlorohydrin.

Each public water system must certify annually in writing to the State (using third party or manufacturer’s certification) that when acrylamide and epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer level does not exceed the levels specified as follows:



Acrylamide = 0.05% dosed at 1 ppm (or equivalent)

Epichlorohydrin = 0.01% dosed at 20 ppm (or equivalent)
Certifications can rely on manufacturers or third parties, as approved by the State.


Subpart L—Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors

§ 141.130 General requirements.

(a) The requirements of this subpart L constitute national primary drinking water regulations.


(1) The regulations in this subpart establish criteria under which community water systems (CWSs) and nontransient, noncommunity water systems (NTNCWSs) which add a chemical disinfectant to the water in any part of the drinking water treatment process must modify their practices to meet MCLs and MRDLs in §§ 141.64 and 141.65, respectively, and must meet the treatment technique requirements for disinfection byproduct precursors in § 141.135.


(2) The regulations in this subpart establish criteria under which transient NCWSs that use chlorine dioxide as a disinfectant or oxidant must modify their practices to meet the MRDL for chlorine dioxide in § 141.65.


(3) EPA has established MCLs for TTHM and HAA5 and treatment technique requirements for disinfection byproduct precursors to limit the levels of known and unknown disinfection byproducts which may have adverse health effects. These disinfection byproducts may include chloroform; bromodichloromethane; dibromochloromethane; bromoform; dichloroacetic acid; and trichloroacetic acid.


(b) Compliance dates—(1) CWSs and NTNCWSs. Unless otherwise noted, systems must comply with the requirements of this subpart as follows. Subpart H systems serving 10,000 or more persons must comply with this subpart beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this subpart beginning January 1, 2004.


(2) Transient NCWSs. Subpart H systems serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with any requirements for chlorine dioxide in this subpart beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and using chlorine dioxide as a disinfectant or oxidant and systems using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with any requirements for chlorine dioxide in this subpart beginning January 1, 2004.


(c) Each CWS and NTNCWS regulated under paragraph (a) of this section must be operated by qualified personnel who meet the requirements specified by the State and are included in a State register of qualified operators.


(d) Control of disinfectant residuals. Notwithstanding the MRDLs in § 141.65, systems may increase residual disinfectant levels in the distribution system of chlorine or chloramines (but not chlorine dioxide) to a level and for a time necessary to protect public health, to address specific microbiological contamination problems caused by circumstances such as, but not limited to, distribution line breaks, storm run-off events, source water contamination events, or cross-connection events.


[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]


§ 141.131 Analytical requirements.

(a) General. (1) Systems must use only the analytical methods specified in this section, or their equivalent as approved by EPA, to demonstrate compliance with the requirements of this subpart and with the requirements of subparts U and V of this part. These methods are effective for compliance monitoring February 16, 1999, unless a different effective date is specified in this section or by the State.


(2) The following documents are incorporated by reference. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be inspected at EPA’s Drinking Water Docket, 1301 Constitution Avenue, NW., EPA West, Room B102, Washington, DC 20460, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. EPA Method 552.1 is in Methods for the Determination of Organic Compounds in Drinking Water-Supplement II, USEPA, August 1992, EPA/600/R-92/129 (available through National Information Technical Service (NTIS), PB92-207703). EPA Methods 502.2, 524.2, 551.1, and 552.2 are in Methods for the Determination of Organic Compounds in Drinking Water-Supplement III, USEPA, August 1995, EPA/600/R-95/131 (available through NTIS, PB95-261616). EPA Method 300.0 is in Methods for the Determination of Inorganic Substances in Environmental Samples, USEPA, August 1993, EPA/600/R-93/100 (available through NTIS, PB94-121811). EPA Methods 300.1 and 321.8 are in Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1, USEPA, August 2000, EPA 815-R-00-014 (available through NTIS, PB2000-106981). EPA Method 317.0, Revision 2.0, “Determination of Inorganic Oxyhalide Disinfection By-Products in Drinking Water Using Ion Chromatography with the Addition of a Postcolumn Reagent for Trace Bromate Analysis,” USEPA, July 2001, EPA 815-B-01-001, EPA Method 326.0, Revision 1.0, “Determination of Inorganic Oxyhalide Disinfection By-Products in Drinking Water Using Ion Chromatography Incorporating the Addition of a Suppressor Acidified Postcolumn Reagent for Trace Bromate Analysis,” USEPA, June 2002, EPA 815-R-03-007, EPA Method 327.0, Revision 1.1, “Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidase with Detection by Visible Spectrophotometry,” USEPA, May 2005, EPA 815-R-05-008 and EPA Method 552.3, Revision 1.0, “Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection,” USEPA, July 2003, EPA-815-B-03-002 can be accessed and downloaded directly on-line at http://www.epa.gov/safewater/methods/sourcalt.html. EPA Method 415.3, Revision 1.1, “Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water,” USEPA, February 2005, EPA/600/R-05/055 can be accessed and downloaded directly on-line at www.epa.gov/nerlcwww/ordmeth.htm. Standard Methods 4500-Cl D, 4500-Cl E, 4500-Cl F, 4500-Cl G, 4500-Cl H, 500-Cl I, 4500-ClO2 D, 4500-ClO2 E, 6251 B, and 5910 B shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 19th or 20th Editions, American Public Health Association, 1995 and 1998, respectively. The cited methods published in either edition may be used. Standard Methods 5310 B, 5310 C, and 5310 D shall be followed in accordance with the Supplement to the 19th Edition of Standard Methods for the Examination of Water and Wastewater, or the Standard Methods for the Examination of Water and Wastewater, 20th Edition, American Public Health Association, 1996 and 1998, respectively. The cited methods published in either edition may be used. Copies may be obtained from the American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. Standard Methods 4500-Cl D-00, 4500-Cl E-00, 4500-Cl F-00, 4500-Cl G-00, 4500-Cl H-00, 4500-Cl I-00, 4500-ClO2 E-00, 6251 B-94, 5310 B-00, 5310 C-00, 5310 D-00 and 5910 B-00 are available at http://www.standardmethods.org or at EPA’s Water Docket. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that are IBR-approved. ASTM Methods D 1253-86 and D 1253-86 (Reapproved 1996) shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 1996 or any ASTM edition containing the IBR-approved version of the method may be used. ASTM Method D1253-03 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2004 or any ASTM edition containing the IBR-approved version of the method may be used. ASTM Method D 6581-00 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2001 or any ASTM edition containing the IBR-approved version of the method may be used; copies may be obtained from the American Society for Testing and Materials International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.


(b) Disinfection byproducts. (1) Systems must measure disinfection byproducts by the methods (as modified by the footnotes) listed in the following table or one of the alternative methods listed in appendix A to subpart C of this part:


Approved Methods for Disinfection Byproduct Compliance Monitoring

Contaminant and methodology
1
EPA method
Standard method
2
SM online
9
ASTM method
3
TTHM
P&T/GC/ElCD & PID502.2
4
P&T/GC/MS524.2
LLE/GC/ECD551.1
HAA5
LLE (diazomethane)/GC/ECD 6251 B
5		6251 B-94
SPE (acidic methanol)/GC/ECD552.1
5
LLE (acidic methanol)/GC/ECD552.2, 552.3
Bromate
Ion chromatography300.1 D 6581-00
Ion chromatography & post column reaction317.0 Rev 2.0
6, 326.0
6
IC/ICP-MS321.8
6 7
Chlorite
Amperometric titration 4500-ClO2 E
8		4500-ClO2 E-00
8
Spectrophotometry327.0 Rev 1.1
8
Ion chromatography300.0, 300.1, 317.0 Rev 2.0, 326.0 D 6581-00


1 P&T = purge and trap; GC = gas chromatography; ElCD = electrolytic conductivity detector; PID = photoionization detector; MS = mass spectrometer; LLE = liquid/liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; IC = ion chromatography; ICP-MS = inductively coupled plasma/mass spectrometer.


2 19th and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1995 and 1998, respectively, American Public Health Association; either of these editions may be used.


3 Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01.


4 If TTHMs are the only analytes being measured in the sample, then a PID is not required.


5 The samples must be extracted within 14 days of sample collection.


6 Ion chromatography & post column reaction or IC/ICP-MS must be used for monitoring of bromate for purposes of demonstrating eligibility of reduced monitoring, as prescribed in § 141.132(b)(3)(ii).


7 Samples must be preserved at the time of sampling with 50 mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days.


8 Amperometric titration or spectrophotometry may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as prescribed in § 141.132(b)(2)(i)(A). Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the distribution system, as prescribed in § 141.132(b)(2)(i)(B) and (b)(2)(ii).


9 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.


(2) Analyses under this section for disinfection byproducts must be conducted by laboratories that have received certification by EPA or the State, except as specified under paragraph (b)(3) of this section. To receive certification to conduct analyses for the DBP contaminants in §§ 141.64, 141.135, and subparts U and V of this part, the laboratory must:


(i) Analyze Performance Evaluation (PE) samples that are acceptable to EPA or the State at least once during each consecutive 12 month period by each method for which the laboratory desires certification.


(ii) Until March 31, 2007, in these analyses of PE samples, the laboratory must achieve quantitative results within the acceptance limit on a minimum of 80% of the analytes included in each PE sample. The acceptance limit is defined as the 95% confidence interval calculated around the mean of the PE study between a maximum and minimum acceptance limit of ±50% and ±15% of the study mean.


(iii) Beginning April 1, 2007, the laboratory must achieve quantitative results on the PE sample analyses that are within the following acceptance limits:


DBP
Acceptance limits (percent of true value)
Comments
TTHM
Chloroform±20Laboratory must meet all 4 individual THM acceptance limits in order to successfully pass a PE sample for TTHM
Bromodichloromethane±20
Dibromochloromethane±20
Bromoform±20
HAA5
Monochloroacetic Acid±40Laboratory must meet the acceptance limits for 4 out of 5 of the HAA5 compounds in order to successfully pass a PE sample for HAA5
Dichloroacetic Acid±40
Trichloroacetic Acid±40
Monobromoacetic Acid±40
Dibromoacetic Acid±40
Chlorite±30
Bromate±30

(iv) Beginning April 1, 2007, report quantitative data for concentrations at least as low as the ones listed in the following table for all DBP samples analyzed for compliance with §§ 141.64, 141.135, and subparts U and V of this part:


DBP
Minimum reporting level (mg/L)
1
Comments
TTHM
2
Chloroform0.0010
Bromodichloromethane0.0010
Dibromochloromethane0.0010
Bromoform0.0010
HAA5
2
Monochloroacetic Acid0.0020
Dichloroacetic Acid0.0010
Trichloroacetic Acid0.0010
Monobromoacetic Acid0.0010
Dibromoacetic Acid0.0010
Chlorite0.020Applicable to monitoring as prescribed in § 141.132(b)(2)(1)(B) and (b)(2)(ii).
Bromate0.0050 or 0.0010Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0 or 321.8 must meet a 0.0010 mg/L MRL for bromate.


1 The calibration curve must encompass the regulatory minimum reporting level (MRL) concentration. Data may be reported for concentrations lower than the regulatory MRL as long as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest reporting limit chosen by the laboratory. The laboratory must verify the accuracy of the calibration curve at the MRL concentration by analyzing an MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for the MRL check standard must be ±50% of the expected value, if any field sample in the batch has a concentration less than 5 times the regulatory MRL. Method requirements to analyze higher concentration check standards and meet tighter acceptance criteria for them must be met in addition to the MRL check standard requirement.


2 When adding the individual trihalomethane or haloacetic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a zero is used for any analytical result that is less than the MRL concentration for that DBP, unless otherwise specified by the State.


(3) A party approved by EPA or the State must measure daily chlorite samples at the entrance to the distribution system.


(c) Disinfectant residuals. (1) Systems must measure residual disinfectant concentration for free chlorine, combined chlorine (chloramines), and chlorine dioxide by the methods listed in the following table or one of the alternative methods listed in appendix A to subpart C of this part:


Methodology
SM (19th or 20th ed)
SM

Online
2
ASTM

method
EPA

method
Residual measured
1
Free

Cl2
Combined

Cl2
Total

Cl2
ClO2
Amperometric Titration4500-Cl D4500-Cl D-00D 1253-86 (96), 03 XXX
Low Level Amperometric Titration4500-Cl E4500-Cl E-00X
DPD Ferrous Titrimetric4500-Cl F4500-Cl F-00XXX
DPD Colorimetric4500-Cl G4500-Cl G-00XXX
Syringaldazine (FACTS)4500-Cl H4500-Cl H-00X
Iodometric Electrode4500-Cl I4500-Cl I-00X
DPD4500-ClO2 DX
Amperometric Method II4500-ClO2 E4500-ClO2 E-00X
Lissamine Green Spectrophotometric327.0 Rev 1.1X


1 X indicates method is approved for measuring specified disinfectant residual. Free chlorine or total chlorine may be measured for demonstrating compliance with the chlorine MRDL and combined chlorine, or total chlorine may be measured for demonstrating compliance with the chloramine MRDL.


2 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.


(2) If approved by the State, systems may also measure residual disinfectant concentrations for chlorine, chloramines, and chlorine dioxide by using DPD colorimetric test kits.


(3) A party approved by EPA or the State must measure residual disinfectant concentration.


(d) Additional analytical methods. Systems required to analyze parameters not included in paragraphs (b) and (c) of this section must use the following methods or one of the alternative methods listed in appendix A to subpart C of this part. A party approved by EPA or the State must measure these parameters.


(1) Alkalinity. All methods allowed in § 141.89(a) for measuring alkalinity.


(2) Bromide. EPA Methods 300.0, 300.1, 317.0 Revision 2.0, 326.0, or ASTM D 6581-00.


(3) Total Organic Carbon (TOC). Standard Method 5310 B or 5310 B-00 (High-Temperature Combustion Method) or Standard Method 5310 C or 5310 C-00 (Persulfate-Ultraviolet or Heated-Persulfate Oxidation Method) or Standard Method 5310 D or 5310 D-00 (Wet-Oxidation Method) or EPA Method 415.3 Revision 1.1. Inorganic carbon must be removed from the samples prior to analysis. TOC samples may not be filtered prior to analysis. TOC samples must be acidified at the time of sample collection to achieve pH less than or equal to 2 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified TOC samples must be analyzed within 28 days.


(4) Specific Ultraviolet Absorbance (SUVA). SUVA is equal to the UV absorption at 254nm (UV254) (measured in m-
1 divided by the dissolved organic carbon (DOC) concentration (measured as mg/L). In order to determine SUVA, it is necessary to separately measure UV254 and DOC. When determining SUVA, systems must use the methods stipulated in paragraph (d)(4)(i) of this section to measure DOC and the method stipulated in paragraph (d)(4)(ii) of this section to measure UV254. SUVA must be determined on water prior to the addition of disinfectants/oxidants by the system. DOC and UV254 samples used to determine a SUVA value must be taken at the same time and at the same location.


(i) Dissolved Organic Carbon (DOC). Standard Method 5310 B or 5310 B-00 (High-Temperature Combustion Method) or Standard Method 5310 C or 5310 C-00 (Persulfate-Ultraviolet or Heated-Persulfate Oxidation Method) or Standard Method 5310 D or 5310 D-00 (Wet-Oxidation Method) or EPA Method 415.3 Revision 1.1. DOC samples must be filtered through the 0.45 μm pore-diameter filter as soon as practical after sampling, not to exceed 48 hours. After filtration, DOC samples must be acidified to achieve pH less than or equal to 2 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified DOC samples must be analyzed within 28 days of sample collection. Inorganic carbon must be removed from the samples prior to analysis. Water passed through the filter prior to filtration of the sample must serve as the filtered blank. This filtered blank must be analyzed using procedures identical to those used for analysis of the samples and must meet the following criteria: DOC

(ii) Ultraviolet Absorption at 254 nm (UV254). Standard Method 5910 B or 5910 B-00 (Ultraviolet Absorption Method) or EPA Method 415.3 Revision 1.1. UV absorption must be measured at 253.7 nm (may be rounded off to 254 nm). Prior to analysis, UV254 samples must be filtered through a 0.45 μm pore-diameter filter. The pH of UV254 samples may not be adjusted. Samples must be analyzed as soon as practical after sampling, not to exceed 48 hours.


(5) pH. All methods allowed in § 141.23(k)(1) for measuring pH.


(6) Magnesium. All methods allowed in § 141.23(k)(1) for measuring magnesium.


[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001; 71 FR 479, Jan. 4, 2006; 71 FR 37168, June 29, 2006; 74 FR 30958, June 29, 2009]


§ 141.132 Monitoring requirements.

(a) General requirements. (1) Systems must take all samples during normal operating conditions.


(2) Systems may consider multiple wells drawing water from a single aquifer as one treatment plant for determining the minimum number of TTHM and HAA5 samples required, with State approval in accordance with criteria developed under § 142.16(h)(5) of this chapter.


(3) Failure to monitor in accordance with the monitoring plan required under paragraph (f) of this section is a monitoring violation.


(4) Failure to monitor will be treated as a violation for the entire period covered by the annual average where compliance is based on a running annual average of monthly or quarterly samples or averages and the system’s failure to monitor makes it impossible to determine compliance with MCLs or MRDLs.


(5) Systems may use only data collected under the provisions of this subpart to qualify for reduced monitoring.


(b) Monitoring requirements for disinfection byproducts—(1) TTHMs and HAA5—(i) Routine monitoring. Systems must monitor at the frequency indicated in the following table:


Routine Monitoring Frequency for TTHM and HAA5

Type of system
Minimum monitoring frequency
Sample location in the distribution system
Subpart H system serving at least 10,000 personsFour water samples per quarter per treatment plantAt least 25 percent of all samples collected each quarter at locations representing maximum residence time. Remaining samples taken at locations representative of at least average residence time in the distribution system and representing the entire distribution system, taking into account number of persons served, different sources of water, and different treatment methods.
1
Subpart H system serving from 500 to 9,999 personsOne water sample per quarter per treatment plantLocations representing maximum residence time.
1
Subpart H system serving fewer than 500 personsOne sample per year per treatment plant during month of warmest water temperature.Locations representing maximum residence time.
1 If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until the system meets criteria in paragraph (b)(1)(iv) of this section.
System using only ground water not under direct influence of surface water using chemical disinfectant and serving at least 10,000 personsOne water sample per quarter per treatment plant
2		Locations representing maximum residence time.
1
System using only ground water not under direct influence of surface water using chemical disinfectant and serving fewer than 10,000 personsOne sample per year per treatment plant
2 during month of warmest water temperature.		Locations representing maximum residence time.
1 If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until the system meets criteria in paragraph (b)(1)(iv) of this section.


1 If a system elects to sample more frequently than the minimum required, at least 25 percent of all samples collected each quarter (including those taken in excess of the required frequency) must be taken at locations that represent the maximum residence time of the water in the distribution system. The remaining samples must be taken at locations representative of at least average residence time in the distribution system.


2 Multiple wells drawing water from a single aquifer may be considered one treatment plant for determining the minimum number of samples required, with State approval in accordance with criteria developed under § 142.16(h)(5) of this chapter.


(ii) Systems may reduce monitoring, except as otherwise provided, in accordance with the following table:


Reduced Monitoring Frequency for TTHM and HAA5

If you are a . . .
You may reduce monitoring if you have monitored at least one year and your . . .
To this level
Subpart H system serving at least 10,000 persons which has a source water annual average TOC level, before any treatment, ≤4.0 mg/LTTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/LOne sample per treatment plant per quarter at distribution system location reflecting maximum residence time.
Subpart H system serving from 500 to 9,999 persons which has a source water annual average TOC level, before any treatment, ≤4.0 mg/LTTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/LOne sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature. NOTE: Any Subpart H system serving fewer than 500 persons may not reduce its monitoring to less than one sample per treatment plant per year.
System using only ground water not under direct influence of surface water using chemical disinfectant and serving at least 10,000 personsTTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/LOne sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature
System using only ground water not under direct influence of surface water using chemical disinfectant and serving fewer than 10,000 personsTTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/L for two consecutive years OR TTHM annual average ≤0.020 mg/L and HAA5 annual average ≤0.015 mg/L for one yearOne sample per treatment plant per three year monitoring cycle at distribution system location reflecting maximum residence time during month of warmest water temperature, with the three-year cycle beginning on January 1 following quarter in which system qualifies for reduced monitoring.

(iii) Monitoring requirements for source water TOC. In order to qualify for reduced monitoring for TTHM and HAA5 under paragraph (b)(1)(ii) of this section, subpart H systems not monitoring under the provisions of paragraph (d) of this section must take monthly TOC samples every 30 days at a location prior to any treatment, beginning April 1, 2008 or earlier, if specified by the State. In addition to meeting other criteria for reduced monitoring in paragraph (b)(1)(ii) of this section, the source water TOC running annual average must be ≤4.0 mg/L (based on the most recent four quarters of monitoring) on a continuing basis at each treatment plant to reduce or remain on reduced monitoring for TTHM and HAA5. Once qualified for reduced monitoring for TTHM and HAA5 under paragraph (b)(1)(ii) of this section, a system may reduce source water TOC monitoring to quarterly TOC samples taken every 90 days at a location prior to any treatment.


(iv) Systems on a reduced monitoring schedule may remain on that reduced schedule as long as the average of all samples taken in the year (for systems which must monitor quarterly) or the result of the sample (for systems which must monitor no more frequently than annually) is no more than 0.060 mg/L and 0.045 mg/L for TTHMs and HAA5, respectively. Systems that do not meet these levels must resume monitoring at the frequency identified in paragraph (b)(1)(i) of this section (minimum monitoring frequency column) in the quarter immediately following the monitoring period in which the system exceeds 0.060 mg/L or 0.045 mg/L for TTHMs and HAA5, respectively. For systems using only ground water not under the direct influence of surface water and serving fewer than 10,000 persons, if either the TTHM annual average is >0.080 mg/L or the HAA5 annual average is >0.060 mg/L, the system must go to the increased monitoring identified in paragraph (b)(1)(i) of this section (sample location column) in the quarter immediately following the monitoring period in which the system exceeds 0.080 mg/L or 0.060 mg/L for TTHMs or HAA5 respectively.


(v) Systems on increased monitoring may return to routine monitoring if, after at least one year of monitoring their TTHM annual average is ≤0.060 mg/L and their HAA5 annual average is ≤0.045 mg/L.


(vi) The State may return a system to routine monitoring at the State’s discretion.


(2) Chlorite. Community and nontransient noncommunity water systems using chlorine dioxide, for disinfection or oxidation, must conduct monitoring for chlorite.


(i) Routine monitoring. (A) Daily monitoring. Systems must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the chlorite MCL, the system must take additional samples in the distribution system the following day at the locations required by paragraph (b)(2)(ii) of this section, in addition to the sample required at the entrance to the distribution system.


(B) Monthly monitoring. Systems must take a three-sample set each month in the distribution system. The system must take one sample at each of the following locations: near the first customer, at a location representative of average residence time, and at a location reflecting maximum residence time in the distribution system. Any additional routine sampling must be conducted in the same manner (as three-sample sets, at the specified locations). The system may use the results of additional monitoring conducted under paragraph (b)(2)(ii) of this section to meet the requirement for monitoring in this paragraph.


(ii) Additional monitoring. On each day following a routine sample monitoring result that exceeds the chlorite MCL at the entrance to the distribution system, the system is required to take three chlorite distribution system samples at the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible (reflecting maximum residence time in the distribution system).


(iii) Reduced monitoring. (A) Chlorite monitoring at the entrance to the distribution system required by paragraph (b)(2)(i)(A) of this section may not be reduced.


(B) Chlorite monitoring in the distribution system required by paragraph (b)(2)(i)(B) of this section may be reduced to one three-sample set per quarter after one year of monitoring where no individual chlorite sample taken in the distribution system under paragraph (b)(2)(i)(B) of this section has exceeded the chlorite MCL and the system has not been required to conduct monitoring under paragraph (b)(2)(ii) of this section. The system may remain on the reduced monitoring schedule until either any of the three individual chlorite samples taken quarterly in the distribution system under paragraph (b)(2)(i)(B) of this section exceeds the chlorite MCL or the system is required to conduct monitoring under paragraph (b)(2)(ii) of this section, at which time the system must revert to routine monitoring.


(3) Bromate—(i) Routine monitoring. Community and nontransient noncommunity systems using ozone, for disinfection or oxidation, must take one sample per month for each treatment plant in the system using ozone. Systems must take samples monthly at the entrance to the distribution system while the ozonation system is operating under normal conditions.


(ii) Reduced monitoring. (A) Until March 31, 2009, systems required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system’s average source water bromide concentration is less than 0.05 mg/L based on representative monthly bromide measurements for one year. The system may remain on reduced bromate monitoring until the running annual average source water bromide concentration, computed quarterly, is equal to or greater than 0.05 mg/L based on representative monthly measurements. If the running annual average source water bromide concentration is ≥0.05 mg/L, the system must resume routine monitoring required by paragraph (b)(3)(i) of this section in the following month.


(B) Beginning April 1, 2009, systems may no longer use the provisions of paragraph (b)(3)(ii)(A) of this section to qualify for reduced monitoring. A system required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system’s running annual average bromate concentration is ≤0.0025 mg/L based on monthly bromate measurements under paragraph (b)(3)(i) of this section for the most recent four quarters, with samples analyzed using Method 317.0 Revision 2.0, 326.0 or 321.8. If a system has qualified for reduced bromate monitoring under paragraph (b)(3)(ii)(A) of this section, that system may remain on reduced monitoring as long as the running annual average of quarterly bromate samples ≤0.0025 mg/L based on samples analyzed using Method 317.0 Revision 2.0, 326.0, or 321.8. If the running annual average bromate concentration is >0.0025 mg/L, the system must resume routine monitoring required by paragraph (b)(3)(i) of this section.


(c) Monitoring requirements for disinfectant residuals—(1) Chlorine and chloramines—(i) Routine monitoring. Until March 31, 2016, community and non-transient non-community water systems that use chlorine or chloramines must measure the residual disinfectant level in the distribution system at the same point in the distribution system and at the same time as total coliforms are sampled, as specified in § 141.21. Beginning April 1, 2016, community and non-transient non-community water systems that use chlorine or chloramines must measure the residual disinfectant level in the distribution system at the same point in the distribution system and at the same time as total coliforms are sampled, as specified in §§ 141.854 through 141.858. Subpart H systems of this part may use the results of residual disinfectant concentration sampling conducted under § 141.74(b)(6)(i) for unfiltered systems or § 141.74(c)(3)(i) for systems which filter, in lieu of taking separate samples.


(ii) Reduced monitoring. Monitoring may not be reduced.


(2) Chlorine dioxide—(i) Routine monitoring. Community, nontransient noncommunity, and transient noncommunity water systems that use chlorine dioxide for disinfection or oxidation must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the MRDL, the system must take samples in the distribution system the following day at the locations required by paragraph (c)(2)(ii) of this section, in addition to the sample required at the entrance to the distribution system.


(ii) Additional monitoring. On each day following a routine sample monitoring result that exceeds the MRDL, the system is required to take three chlorine dioxide distribution system samples. If chlorine dioxide or chloramines are used to maintain a disinfectant residual in the distribution system, or if chlorine is used to maintain a disinfectant residual in the distribution system and there are no disinfection addition points after the entrance to the distribution system (i.e., no booster chlorination), the system must take three samples as close to the first customer as possible, at intervals of at least six hours. If chlorine is used to maintain a disinfectant residual in the distribution system and there are one or more disinfection addition points after the entrance to the distribution system (i.e., booster chlorination), the system must take one sample at each of the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible (reflecting maximum residence time in the distribution system).


(iii) Reduced monitoring. Chlorine dioxide monitoring may not be reduced.


(d) Monitoring requirements for disinfection byproduct precursors (DBPP)—(1) Routine monitoring. Subpart H systems which use conventional filtration treatment (as defined in § 141.2) must monitor each treatment plant for TOC no later than the point of combined filter effluent turbidity monitoring and representative of the treated water. All systems required to monitor under this paragraph (d)(1) must also monitor for TOC in the source water prior to any treatment at the same time as monitoring for TOC in the treated water. These samples (source water and treated water) are referred to as paired samples. At the same time as the source water sample is taken, all systems must monitor for alkalinity in the source water prior to any treatment. Systems must take one paired sample and one source water alkalinity sample per month per plant at a time representative of normal operating conditions and influent water quality.


(2) Reduced monitoring. Subpart H systems with an average treated water TOC of less than 2.0 mg/L for two consecutive years, or less than 1.0 mg/L for one year, may reduce monitoring for both TOC and alkalinity to one paired sample and one source water alkalinity sample per plant per quarter. The system must revert to routine monitoring in the month following the quarter when the annual average treated water TOC ≥2.0 mg/L.


(e) Bromide. Systems required to analyze for bromate may reduce bromate monitoring from monthly to once per quarter, if the system demonstrates that the average source water bromide concentration is less than 0.05 mg/L based upon representative monthly measurements for one year. The system must continue bromide monitoring to remain on reduced bromate monitoring.


(f) Monitoring plans. Each system required to monitor under this subpart must develop and implement a monitoring plan. The system must maintain the plan and make it available for inspection by the State and the general public no later than 30 days following the applicable compliance dates in § 141.130(b). All Subpart H systems serving more than 3300 people must submit a copy of the monitoring plan to the State no later than the date of the first report required under § 141.134. The State may also require the plan to be submitted by any other system. After review, the State may require changes in any plan elements. The plan must include at least the following elements.


(1) Specific locations and schedules for collecting samples for any parameters included in this subpart.


(2) How the system will calculate compliance with MCLs, MRDLs, and treatment techniques.


(3) If approved for monitoring as a consecutive system, or if providing water to a consecutive system, under the provisions of § 141.29, the sampling plan must reflect the entire distribution system.


[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001; 69 FR 38856, June 29, 2004; 71 FR 482, Jan. 4, 2006; 78 FR 10348, Feb. 13, 2013]


§ 141.133 Compliance requirements.

(a) General requirements. (1) Where compliance is based on a running annual average of monthly or quarterly samples or averages and the system fails to monitor for TTHM, HAA5, or bromate, this failure to monitor will be treated as a monitoring violation for the entire period covered by the annual average. Where compliance is based on a running annual average of monthly or quarterly samples or averages and the system failure to monitor makes it impossible to determine compliance with MRDLs for chlorine and chloramines, this failure to monitor will be treated as a monitoring violation for the entire period covered by the annual average.


(2) All samples taken and analyzed under the provisions of this subpart must be included in determining compliance, even if that number is greater than the minimum required.


(3) If, during the first year of monitoring under § 141.132, any individual quarter’s average will cause the running annual average of that system to exceed the MCL for total trihalomethanes, haloacetic acids (five), or bromate; or the MRDL for chlorine or chloramine, the system is out of compliance at the end of that quarter.


(b) Disinfection byproducts—(1) TTHMs and HAA5. (i) For systems monitoring quarterly, compliance with MCLs in § 141.64 must be based on a running annual arithmetic average, computed quarterly, of quarterly arithmetic averages of all samples collected by the system as prescribed by § 141.132(b)(1).


(ii) For systems monitoring less frequently than quarterly, systems demonstrate MCL compliance if the average of samples taken that year under the provisions of § 141.132(b)(1) does not exceed the MCLs in § 141.64. If the average of these samples exceeds the MCL, the system must increase monitoring to once per quarter per treatment plant and such a system is not in violation of the MCL until it has completed one year of quarterly monitoring, unless the result of fewer than four quarters of monitoring will cause the running annual average to exceed the MCL, in which case the system is in violation at the end of that quarter. Systems required to increase monitoring frequency to quarterly monitoring must calculate compliance by including the sample which triggered the increased monitoring plus the following three quarters of monitoring.


(iii) If the running annual arithmetic average of quarterly averages covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to § 141.32 or § 141.202, whichever is effective for your system, in addition to reporting to the State pursuant to § 141.134.


(iv) If a PWS fails to complete four consecutive quarters of monitoring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.


(2) Bromate. Compliance must be based on a running annual arithmetic average, computed quarterly, of monthly samples (or, for months in which the system takes more than one sample, the average f all samples taken during the month) collected by the system as prescribed by § 141.132(b)(3). If the average of samples covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to subpart Q, in addition to reporting to the State pursuant to § 141.134. If a PWS fails to complete 12 consecutive months’ monitoring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.


(3) Chlorite. Compliance must be based on an arithmetic average of each three sample set taken in the distribution system as prescribed by § 141.132(b)(2)(i)(B) and § 141.132(b)(2)(ii). If the arithmetic average of any three sample set exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to subpart Q, in addition to reporting to the State pursuant to § 141.134.


(c) Disinfectant residuals—(1) Chlorine and chloramines. (i) Compliance must be based on a running annual arithmetic average, computed quarterly, of monthly averages of all samples collected by the system under § 141.132(c)(1). If the average covering any consecutive four-quarter period exceeds the MRDL, the system is in violation of the MRDL and must notify the public pursuant to subpart Q, in addition to reporting to the State pursuant to § 141.134.


(ii) In cases where systems switch between the use of chlorine and chloramines for residual disinfection during the year, compliance must be determined by including together all monitoring results of both chlorine and chloramines in calculating compliance. Reports submitted pursuant to § 141.134 must clearly indicate which residual disinfectant was analyzed for each sample.


(2) Chlorine dioxide. (i) Acute violations. Compliance must be based on consecutive daily samples collected by the system under § 141.132(c)(2). If any daily sample taken at the entrance to the distribution system exceeds the MRDL, and on the following day one (or more) of the three samples taken in the distribution system exceed the MRDL, the system is in violation of the MRDL and must take immediate corrective action to lower the level of chlorine dioxide below the MRDL and must notify the public pursuant to the procedures for acute health risks in subpart Q in addition to reporting to the State pursuant to § 141.134. Failure to take samples in the distribution system the day following an exceedance of the chlorine dioxide MRDL at the entrance to the distribution system will also be considered an MRDL violation and the system must notify the public of the violation in accordance with the provisions for acute violations under subpart Q in addition to reporting to the State pursuant to § 141.134.


(ii) Nonacute violations. Compliance must be based on consecutive daily samples collected by the system under § 141.132(c)(2). If any two consecutive daily samples taken at the entrance to the distribution system exceed the MRDL and all distribution system samples taken are below the MRDL, the system is in violation of the MRDL and must take corrective action to lower the level of chlorine dioxide below the MRDL at the point of sampling and will notify the public pursuant to the procedures for nonacute health risks in subpart Q in addition to reporting to the State pursuant to § 141.134. Failure to monitor at the entrance to the distribution system the day following an exceedance of the chlorine dioxide MRDL at the entrance to the distribution system is also an MRDL violation and the system must notify the public of the violation in accordance with the provisions for nonacute violations under § 141.32(e)(78) in addition to reporting to the State pursuant to § 141.134.


(d) Disinfection byproduct precursors (DBPP). Compliance must be determined as specified by § 141.135(c). Systems may begin monitoring to determine whether Step 1 TOC removals can be met 12 months prior to the compliance date for the system. This monitoring is not required and failure to monitor during this period is not a violation. However, any system that does not monitor during this period, and then determines in the first 12 months after the compliance date that it is not able to meet the Step 1 requirements in § 141.135(b)(2) and must therefore apply for alternate minimum TOC removal (Step 2) requirements, is not eligible for retroactive approval of alternate minimum TOC removal (Step 2) requirements as allowed pursuant to § 141.135(b)(3) and is in violation. Systems may apply for alternate minimum TOC removal (Step 2) requirements any time after the compliance date. For systems required to meet Step 1 TOC removals, if the value calculated under § 141.135(c)(1)(iv) is less than 1.00, the system is in violation of the treatment technique requirements and must notify the public pursuant to subpart Q of this part, in addition to reporting to the State pursuant to § 141.134.


[63 FR 69466, Dec. 16, 1998, as amended at 65 FR 26022, May 4, 2000; 65 FR 40521, June 30, 2000; 66 FR 3777, Jan. 16, 2001; 69 FR 38856, June 29, 2004; 71 FR 482, Jan. 4, 2006]


§ 141.134 Reporting and recordkeeping requirements.

(a) Systems required to sample quarterly or more frequently must report to the State within 10 days after the end of each quarter in which samples were collected, notwithstanding the provisions of § 141.31. Systems required to sample less frequently than quarterly must report to the State within 10 days after the end of each monitoring period in which samples were collected.


(b) Disinfection byproducts. Systems must report the information specified in the following table:


If you are a * * *
You must report * * *
(1) System monitoring for TTHMs and HAA5 under the requirements of § 141.132(b) on a quarterly or more frequent basis.(i) The number of samples taken during the last quarter.

(ii) The location, date, and result of each sample taken during the last quarter.

(iii) The arithmetic average of all samples taken in the last quarter.

(iv) The annual arithmetic average of the quarterly arithmetic averages of this section for the last four quarters.

(v) Whether, based on § 141.133(b)(1), the MCL was violated.
(2) System monitoring for TTHMs and HAA5 under the requirements of § 141.132(b) less frequently than quarterly (but as least annually).(i) The number of samples taken during the last year.

(ii) The location, date, and result of each sample taken during the last monitoring period.

(iii) The arithmetic average of all samples taken over the last year.

(iv) Whether, based on § 141.133(b)(1), the MCL was violated.
(3) System monitoring for TTHMs and HAA5 under the requriements of § 141.132(b) less frequently than annually.(i) The location, date, and result of each sample taken

(ii) Whether, based on § 141.133(b)(1), the MCL was violated.
(4) System monitoring for chlorite under the requirements of § 141.132(b)(i) The number of entry point samples taken each month for the last 3 months.

(ii) The location, date, and result of each sample (both entry point and distribution system) taken during the last quarter.

(iii) For each month in the reporting period, the arithmetic average of all samples taken in each three samples set taken in the distribution system.

(iv) Whether, based on § 141.133(b)(3), the MCL was violated, in which month, and how many times it was violated each month.
(5) System monitoring for bromate under the requirements of § 141.132(b).(i)The number of samples taken during the last quarter.

(ii)The location, date, and result of each sample taken during the last quarter.

(iii) The arithmetic average of the monthly arithmetic averages of all samples taken in the last year.

(iv) Whether, based on § 141.133(b)(2), the MCL was violated.


1 The State may choose to perform calculations and determine whether the MCL was exceeded, in lieu of having the system report that information


(c) Disinfectants. Systems must report the information specified in the following table:


If you are a * * *
You must report * * *
(1) System monitoring for chlorine or chloramines under the requirements of § 141.132(c)(i) The number of samples taken during each month of the last quarter.

(ii) The month arithmetic average of all samples taken in each month for the last 12 months.

(iii) The arithmetic average of the monthly averages for the last 12 months.

(iv) Whether, based on § 141.133(c)(1), the MRD was violated.
(2) System monitoring for chlorine dioxide under the requirements of § 141.132(c).(i) The dates, result, and locations of samples taken during the last quarter.

(ii) Whether, based on § 141.133(c)(2), the MRDL was violated.

(iii) Whether the MRDL was exceeded in any two consecutive daily samples and whether the resulting violation was acuate or nonacute.


1 The State may choose to perform calculations and determine whether the MRDL was exceeded, in lieu of having the system report that information.


(d) Disinfection byproduct precursors and enhanced coagulation or enhanced softening. Systems must report the information specified in the following table:


If you are a. . .
You must report. . .
1
(1) System monitoring monthly or quarterly for TOC under the requirements of § 141.132(d) and required to meet the enhanced coagulation or enhanced softening requirements in § 141.135(b)(2) or (3)(i) The number of paired (source water and treated water) samples taken during the last quarter.

(ii) The location, date, and results of each paired sample and associated alkalinity taken during the last quarter.

(iii) For each month in the reporting period that paired samples were taken, the arithmetic average of the percent reduction of TOC for each paired sample and the required TOC percent removal.

(iv) Calculations for determining compliance with the TOC percent removal requirements, as provided in § 141.135(c)(1).

(v) Whether the system is in compliance with the enhanced coagulation or enhanced softening percent removal requirements in § 141.135(b) for the last four quarters.
(2) System monitoring monthly or quarterly for TOC under the requirements of § 141.132(d) and meeting one or more of the alternative compliance criteria in § 141.135(a)(2) or (3)(i) The alternative compliance criterion that the system is using.
(ii) The number of paired samples taken during the last quarter.
(iii) The location, date, and result of each paired sample and associated alkalinity taken during the last quarter.
(iv) The running annual arithmetic average based on monthly averages (or quarterly samples) of source water TOC for systems meeting a criterion in §§ 141.135(a)(2)(i) or (iii) or of treated water TOC for systems meeting the criterion in § 141.135(a)(2)(ii).
(v) The running annual arithmetic average based on monthly averages (or quarterly samples) of source water SUVA for systems meeting the criterion in § 141.135(a)(2)(v) or of treated water SUVA for systems meeting the criterion in § 141.135(a)(2)(vi).
(vi) The running annual average of source water alkalinity for systems meeting the criterion in § 141.135(a)(2)(iii) and of treated water alkalinity for systems meeting the criterion in § 141.135(a)(3)(i).
(vii) The running annual average for both TTHM and HAA5 for systems meeting the criterion in § 141.135(a)(2)(iii) or (iv).
(viii) The running annual average of the amount of magnesium hardness removal (as CaCO3, in mg/L) for systems meeting the criterion in § 141.135(a)(3)(ii).
(ix) Whether the system is in compliance with the particular alternative compliance criterion in § 141.135(a)(2) or (3).


1 The State may choose to perform calculations and determine whether the treatment technique was met, in lieu of having the system report that information.


[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3778, Jan. 16, 2001; 66 FR 9903, Feb. 12, 2001]


§ 141.135 Treatment technique for control of disinfection byproduct (DBP) precursors.

(a) Applicability. (1) Subpart H systems using conventional filtration treatment (as defined in § 141.2) must operate with enhanced coagulation or enhanced softening to achieve the TOC percent removal levels specified in paragraph (b) of this section unless the system meets at least one of the alternative compliance criteria listed in paragraph (a)(2) or (a)(3) of this section.


(2) Alternative compliance criteria for enhanced coagulation and enhanced softening systems. Subpart H systems using conventional filtration treatment may use the alternative compliance criteria in paragraphs (a)(2)(i) through (vi) of this section to comply with this section in lieu of complying with paragraph (b) of this section. Systems must still comply with monitoring requirements in § 141.132(d).


(i) The system’s source water TOC level, measured according to § 141.131(d)(3), is less than 2.0 mg/L, calculated quarterly as a running annual average.


(ii) The system’s treated water TOC level, measured according to § 141.131(d)(3), is less than 2.0 mg/L, calculated quarterly as a running annual average.


(iii) The system’s source water TOC level, measured according to § 141.131(d)(3), is less than 4.0 mg/L, calculated quarterly as a running annual average; the source water alkalinity, measured according to § 141.131(d)(1), is greater than 60 mg/L (as CaCO3), calculated quarterly as a running annual average; and either the TTHM and HAA5 running annual averages are no greater than 0.040 mg/L and 0.030 mg/L, respectively; or prior to the effective date for compliance in § 141.130(b), the system has made a clear and irrevocable financial commitment not later than the effective date for compliance in § 141.130(b) to use of technologies that will limit the levels of TTHMs and HAA5 to no more than 0.040 mg/L and 0.030 mg/L, respectively. Systems must submit evidence of a clear and irrevocable financial commitment, in addition to a schedule containing milestones and periodic progress reports for installation and operation of appropriate technologies, to the State for approval not later than the effective date for compliance in § 141.130(b). These technologies must be installed and operating not later than June 30, 2005. Failure to install and operate these technologies by the date in the approved schedule will constitute a violation of National Primary Drinking Water Regulations.


(iv) The TTHM and HAA5 running annual averages are no greater than 0.040 mg/L and 0.030 mg/L, respectively, and the system uses only chlorine for primary disinfection and maintenance of a residual in the distribution system.


(v) The system’s source water SUVA, prior to any treatment and measured monthly according to § 141.131(d)(4), is less than or equal to 2.0 L/mg-m, calculated quarterly as a running annual average.


(vi) The system’s finished water SUVA, measured monthly according to § 141.131(d)(4), is less than or equal to 2.0 L/mg-m, calculated quarterly as a running annual average.


(3) Additional alternative compliance criteria for softening systems. Systems practicing enhanced softening that cannot achieve the TOC removals required by paragraph (b)(2) of this section may use the alternative compliance criteria in paragraphs (a)(3)(i) and (ii) of this section in lieu of complying with paragraph (b) of this section. Systems must still comply with monitoring requirements in § 141.132(d).


(i) Softening that results in lowering the treated water alkalinity to less than 60 mg/L (as CaCO3), measured monthly according to § 141.131(d)(1) and calculated quarterly as a running annual average.


(ii) Softening that results in removing at least 10 mg/L of magnesium hardness (as CaCO3), measured monthly according to § 141.131(d)(6) and calculated quarterly as a running annual average.


(b) Enhanced coagulation and enhanced softening performance requirements. (1) Systems must achieve the percent reduction of TOC specified in paragraph (b)(2) of this section between the source water and the combined filter effluent, unless the State approves a system’s request for alternate minimum TOC removal (Step 2) requirements under paragraph (b)(3) of this section.


(2) Required Step 1 TOC reductions, indicated in the following table, are based upon specified source water parameters measured in accordance with § 141.131(d). Systems practicing softening are required to meet the Step 1 TOC reductions in the far-right column (Source water alkalinity >120 mg/L) for the specified source water TOC:


Step 1 Required Removal of TOC by Enhanced Coagulation and Enhanced Softening for Subpart H Systems Using Conventional Treatment
1 2

Source-water

TOC, mg/L
Source-water alkalinity, mg/L as CaCO 3 (in precentages)
0-60
>60-120
>120
3
>2.0-4.035.025.015.0
>4.0-8.045.035.025.0
>8.0.50.040.030.0


1 Systems meeting at least one of the conditions in paragraph (a)(2)(i)-(vi) of this section are not required to operate with enhanced coagulation.


2 Softening system meeting one of the alternative compliance criteria in paragraph (a)(3) of this section are not required to operate with enhanced softening.


3 System practicing softening must meet the TOC removal requirements in this column.


(3) Subpart H conventional treatment systems that cannot achieve the Step 1 TOC removals required by paragraph (b)(2) of this section due to water quality parameters or operational constraints must apply to the State, within three months of failure to achieve the TOC removals required by paragraph (b)(2) of this section, for approval of alternative minimum TOC (Step 2) removal requirements submitted by the system. If the State approves the alternative minimum TOC removal (Step 2) requirements, the State may make those requirements retroactive for the purposes of determining compliance. Until the State approves the alternate minimum TOC removal (Step 2) requirements, the system must meet the Step 1 TOC removals contained in paragraph (b)(2) of this section.


(4) Alternate minimum TOC removal (Step 2) requirements. Applications made to the State by enhanced coagulation systems for approval of alternate minimum TOC removal (Step 2) requirements under paragraph (b)(3) of this section must include, at a minimum, results of bench- or pilot-scale testing conducted under paragraph (b)(4)(i) of this section. The submitted bench- or pilot-scale testing must be used to determine the alternate enhanced coagulation level.


(i) Alternate enhanced coagulation level is defined as coagulation at a coagulant dose and pH as determined by the method described in paragraphs (b)(4)(i) through (v) of this section such that an incremental addition of 10 mg/L of alum (or equivalent amount of ferric salt) results in a TOC removal of ≤0.3 mg/L. The percent removal of TOC at this point on the “TOC removal versus coagulant dose” curve is then defined as the minimum TOC removal required for the system. Once approved by the State, this minimum requirement supersedes the minimum TOC removal required by the table in paragraph (b)(2) of this section. This requirement will be effective until such time as the State approves a new value based on the results of a new bench- and pilot-scale test. Failure to achieve State-set alternative minimum TOC removal levels is a violation of National Primary Drinking Water Regulations.


(ii) Bench- or pilot-scale testing of enhanced coagulation must be conducted by using representative water samples and adding 10 mg/L increments of alum (or equivalent amounts of ferric salt) until the pH is reduced to a level less than or equal to the enhanced coagulation Step 2 target pH shown in the following table:


Enhanced Coagulation Step 2 target pH

Alkalinity (mg/L as CaCO3)
Target pH
0-605.5
>60-1206.3
>120-2407.0
>2407.5

(iii) For waters with alkalinities of less than 60 mg/L for which addition of small amounts of alum or equivalent addition of iron coagulant drives the pH below 5.5 before significant TOC removal occurs, the system must add necessary chemicals to maintain the pH between 5.3 and 5.7 in samples until the TOC removal of 0.3 mg/L per 10 mg/L alum added (or equivalant addition of iron coagulant) is reached.


(iv) The system may operate at any coagulant dose or pH necessary (consistent with other NPDWRs) to achieve the minimum TOC percent removal approved under paragraph (b)(3) of this section.


(v) If the TOC removal is consistently less than 0.3 mg/L of TOC per 10 mg/L of incremental alum dose at all dosages of alum (or equivalant addition of iron coagulant), the water is deemed to contain TOC not amenable to enhanced coagulation. The system may then apply to the State for a waiver of enhanced coagulation requirements.


(c) Compliance calculations. (1) Subpart H systems other than those identified in paragraph (a)(2) or (a)(3) of this section must comply with requirements contained in paragraph (b)(2) or (b)(3) of this section. Systems must calculate compliance quarterly, beginning after the system has collected 12 months of data, by determining an annual average using the following method:


(i) Determine actual monthly TOC percent removal, equal to:


(1−(treated water TOC/source water TOC)) × 100

(ii) Determine the required monthly TOC percent removal (from either the table in paragraph (b)(2) of this section or from paragraph (b)(3) of this section).


(iii) Divide the value in paragraph (c)(1)(i) of this section by the value in paragraph (c)(1)(ii) of this section.


(iv) Add together the results of paragraph (c)(1)(iii) of this section for the last 12 months and divide by 12.


(v) If the value calculated in paragraph (c)(1)(iv) of this section is less than 1.00, the system is not in compliance with the TOC percent removal requirements.


(2) Systems may use the provisions in paragraphs (c)(2)(i) through (v) of this section in lieu of the calculations in paragraph (c)(1)(i) through (v) of this section to determine compliance with TOC percent removal requirements.


(i) In any month that the system’s treated or source water TOC level, measured according to § 141.131(d)(3), is less than 2.0 mg/L, the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.


(ii) In any month that a system practicing softening removes at least 10 mg/L of magnesium hardness (as CaCO3), the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.


(iii) In any month that the system’s source water SUVA, prior to any treatment and measured according to § 141.131(d)(4), is ≤2.0 L/mg-m, the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.


(iv) In any month that the system’s finished water SUVA, measured according to § 141.131(d)(4), is ≤2.0 L/mg-m, the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.


(v) In any month that a system practicing enhanced softening lowers alkalinity below 60 mg/L (as CaCO3), the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.


(3) Subpart H systems using conventional treatment may also comply with the requirements of this section by meeting the criteria in paragraph (a)(2) or (3) of this section.


(d) Treatment technique requirements for DBP precursors. The Administrator identifies the following as treatment techniques to control the level of disinfection byproduct precursors in drinking water treatment and distribution systems: For Subpart H systems using conventional treatment, enhanced coagulation or enhanced softening.


[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3779, Jan. 16, 2001; 71 FR 482, Jan. 4, 2006]


Subparts M-N [Reserved]

Subpart O—Consumer Confidence Reports


Source:63 FR 44526, Aug. 19, 1998, unless otherwise noted.

§ 141.151 Purpose and applicability of this subpart.

(a) This subpart establishes the minimum requirements for the content of annual reports that community water systems must deliver to their customers. These reports must contain information on the quality of the water delivered by the systems and characterize the risks (if any) from exposure to contaminants detected in the drinking water in an accurate and understandable manner.


(b) Notwithstanding the provisions of § 141.3, this subpart applies only to community water systems.


(c) For the purpose of this subpart, customers are defined as billing units or service connections to which water is delivered by a community water system.


(d) For the purpose of this subpart, detected means: at or above the levels prescribed by § 141.23(a)(4) for inorganic contaminants, at or above the levels prescribed by § 141.24(f)(7) for the contaminants listed in § 141.61(a), at or above the levels prescribed by § 141.24(h)(18) for the contaminants listed in § 141.61(c), at or above the levels prescribed by § 141.131(b)(2)(iv) for the contaminants or contaminant groups listed in § 141.64, and at or above the levels prescribed by § 141.25(c) for radioactive contaminants.


(e) A State that has primary enforcement responsibility may adopt by rule, after notice and comment, alternative requirements for the form and content of the reports. The alternative requirements must provide the same type and amount of information as required by §§ 141.153 and 141.154, and must be designed to achieve an equivalent level of public information and education as would be achieved under this subpart.


(f) For purpose of §§ 141.154 and 141.155 of this subpart, the term “primacy agency” refers to the State or tribal government entity that has jurisdiction over, and primary enforcement responsibility for, public water systems, even if that government does not have interim or final primary enforcement responsibility for this rule. Where the State or tribe does not have primary enforcement responsibility for public water systems, the term “primacy agency” refers to the appropriate EPA regional office.


[63 FR 44526, Aug. 19, 1998, as amended at 71 FR 483, Jan. 4, 2006]


§ 141.152 Effective dates.

(a) The regulations in this subpart shall take effect on September 18, 1998.


(b) Each existing community water system must deliver its first report by October 19, 1999, its second report by July 1, 2000, and subsequent reports by July 1 annually thereafter. The first report must contain data collected during, or prior to, calendar year 1998 as prescribed in § 141.153(d)(3). Each report thereafter must contain data collected during, or prior to, the previous calendar year.


(c) A new community water system must deliver its first report by July 1 of the year after its first full calendar year in operation and annually thereafter.


(d) A community water system that sells water to another community water system must deliver the applicable information required in § 141.153 to the buyer system:


(1) No later than April 19, 1999, by April 1, 2000, and by April 1 annually thereafter or


(2) On a date mutually agreed upon by the seller and the purchaser, and specifically included in a contract between the parties.


§ 141.153 Content of the reports.

(a) Each community water system must provide to its customers an annual report that contains the information specified in this section and § 141.154.


(b) Information on the source of the water delivered:


(1) Each report must identify the source(s) of the water delivered by the community water system by providing information on:


(i) The type of the water: e.g., surface water, ground water; and


(ii) The commonly used name (if any) and location of the body (or bodies) of water.


(2) If a source water assessment has been completed, the report must notify consumers of the availability of this information and the means to obtain it. In addition, systems are encouraged to highlight in the report significant sources of contamination in the source water area if they have readily available information. Where a system has received a source water assessment from the primacy agency, the report must include a brief summary of the system’s susceptibility to potential sources of contamination, using language provided by the primacy agency or written by the operator.


(c) Definitions. (1) Each report must include the following definitions:


(i) Maximum Contaminant Level Goal or MCLG: The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.


(ii) Maximum Contaminant Level or MCL: The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.


(2) A report for a community water system operating under a variance or an exemption issued under § 1415 or 1416 of SDWA must include the following definition: Variances and Exemptions: State or EPA permission not to meet an MCL or a treatment technique under certain conditions.


(3) A report that contains data on contaminants that EPA regulates using any of the following terms must include the applicable definitions:


(i) Treatment Technique: A required process intended to reduce the level of a contaminant in drinking water.


(ii) Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.


(iii) Maximum residual disinfectant level goal or MRDLG: The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.


(iv) Maximum residual disinfectant level or MRDL: The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.


(4) A report that contains information regarding a Level 1 or Level 2 Assessment required under Subpart Y of this part must include the applicable definitions:


(i) Level 1 Assessment: A Level 1 assessment is a study of the water system to identify potential problems and determine (if possible) why total coliform bacteria have been found in our water system.


(ii) Level 2 Assessment: A Level 2 assessment is a very detailed study of the water system to identify potential problems and determine (if possible) why an E. coli MCL violation has occurred and/or why total coliform bacteria have been found in our water system on multiple occasions.


(d) Information on detected contaminants. (1) This sub-section specifies the requirements for information to be included in each report for contaminants subject to mandatory monitoring (except Cryptosporidium). It applies to:


(i) Contaminants subject to a MCL, action level, maximum residual disinfectant level, or treatment technique (regulated contaminants).


(ii) Contaminants for which monitoring is required by § 141.40 (unregulated contaminants); and


(iii) Disinfection by-products or microbial contaminants for which monitoring is required by §§ 141.142 and 141.143, except as provided under paragraph (e)(1) of this section, and which are detected in the finished water.


(2) The data relating to these contaminants must be displayed in one table or in several adjacent tables. Any additional monitoring results which a community water system chooses to include in its report must be displayed separately.


(3) The data must be derived from data collected to comply with EPA and State monitoring and analytical requirements during calendar year 1998 for the first report and subsequent calendar years thereafter except that:


(i) Where a system is allowed to monitor for regulated contaminants less often than once a year, the table(s) must include the date and results of the most recent sampling and the report must include a brief statement indicating that the data presented in the report are from the most recent testing done in accordance with the regulations. No data older than 5 years need be included.


(ii) Results of monitoring in compliance with §§ 141.142 and 141.143 need only be included for 5 years from the date of last sample or until any of the detected contaminants becomes regulated and subject to routine monitoring requirements, whichever comes first.


(4) For detected regulated contaminants (listed in appendix A to this subpart), the table(s) must contain:


(i) The MCL for that contaminant expressed as a number equal to or greater than 1.0 (as provided in appendix A to this subpart);


(ii) The MCLG for that contaminant expressed in the same units as the MCL;


(iii) If there is no MCL for a detected contaminant, the table must indicate that there is a treatment technique, or specify the action level, applicable to that contaminant, and the report must include the definitions for treatment technique and/or action level, as appropriate, specified in paragraph (c)(3) of this section;


(iv) For contaminants subject to an MCL, except turbidity, total coliform, fecal coliform and E. coli, the highest contaminant level used to determine compliance with an NPDWR and the range of detected levels, as follows:


(A) When compliance with the MCL is determined annually or less frequently: The highest detected level at any sampling point and the range of detected levels expressed in the same units as the MCL.


(B) When compliance with the MCL is determined by calculating a running annual average of all samples taken at a monitoring location: the highest average of any of the monitoring locations and the range of all monitoring locations expressed in the same units as the MCL. For the MCLs for TTHM and HAA5 in § 141.64(b)(2), systems must include the highest locational running annual average for TTHM and HAA5 and the range of individual sample results for all monitoring locations expressed in the same units as the MCL. If more than one location exceeds the TTHM or HAA5 MCL, the system must include the locational running annual averages for all locations that exceed the MCL.


(C) When compliance with the MCL is determined on a system-wide basis by calculating a running annual average of all samples at all monitoring locations: the average and range of detection expressed in the same units as the MCL. The system is required to include individual sample results for the IDSE conducted under subpart U of this part when determining the range of TTHM and HAA5 results to be reported in the annual consumer confidence report for the calendar year that the IDSE samples were taken.



Note to paragraph (d)(4)(iv):

When rounding of results to determine compliance with the MCL is allowed by the regulations, rounding should be done prior to multiplying the results by the factor listed in appendix A of this subpart.


(v) For turbidity.


(A) When it is reported pursuant to § 141.13: The highest average monthly value.


(B) When it is reported pursuant to the requirements of § 141.71: the highest monthly value. The report should include an explanation of the reasons for measuring turbidity.


(C) When it is reported pursuant to § 141.73 or § 141.173 or § 141.551: the highest single measurement and the lowest monthly percentage of samples meeting the turbidity limits specified in § 141.73 or § 141.173, or § 141.551 for the filtration technology being used. The report should include an explanation of the reasons for measuring turbidity;


(vi) For lead and copper: the 90th percentile concentration of the most recent round(s) of sampling, the number of sampling sites exceeding the action level, and the range of tap sampling results;


(vii) For total coliform analytical results until March 31, 2016:


(A) The highest monthly number of positive samples for systems collecting fewer than 40 samples per month; or


(B) The highest monthly percentage of positive samples for systems collecting at least 40 samples per month;


(viii) For fecal coliform and E. coli until March 31, 2016: The total number of positive samples;


(ix) The likely source(s) of detected contaminants to the best of the operator’s knowledge. Specific information regarding contaminants may be available in sanitary surveys and source water assessments, and should be used when available to the operator. If the operator lacks specific information on the likely source, the report must include one or more of the typical sources for that contaminant listed in appendix A to this subpart that is most applicable to the system;


(x) For E. coli analytical results under subpart Y: The total number of positive samples;


(xi) The report shall include a statement that a service line inventory (including inventories consisting only of a statement that there are no lead service lines) has been prepared and include instructions to access the service line inventory; and


(xii) The report shall notify consumers that complete lead tap sampling data are available for review and shall include information on how to access the data.


(5) If a community water system distributes water to its customers from multiple hydraulically independent distribution systems that are fed by different raw water sources, the table should contain a separate column for each service area and the report should identify each separate distribution system. Alternatively, systems could produce separate reports tailored to include data for each service area.


(6) The table(s) must clearly identify any data indicating violations of MCLs, MRDLs, or treatment techniques, and the report must contain a clear and readily understandable explanation of the violation including: the length of the violation, the potential adverse health effects, and actions taken by the system to address the violation. To describe the potential health effects, the system must use the relevant language of appendix A to this subpart.


(7) For detected unregulated contaminants for which monitoring is required (except Cryptosporidium), the table(s) must contain the average and range at which the contaminant was detected. The report may include a brief explanation of the reasons for monitoring for unregulated contaminants.


(e) Information on Cryptosporidium, radon, and other contaminants:


(1) If the system has performed any monitoring for Cryptosporidium, including monitoring performed to satisfy the requirements of § 141.143, which indicates that Cryptosporidium may be present in the source water or the finished water, the report must include:


(i) A summary of the results of the monitoring; and


(ii) An explanation of the significance of the results.


(2) If the system has performed any monitoring for radon which indicates that radon may be present in the finished water, the report must include:


(i) The results of the monitoring; and


(ii) An explanation of the significance of the results.


(3) If the system has performed additional monitoring which indicates the presence of other contaminants in the finished water, EPA strongly encourages systems to report any results which may indicate a health concern. To determine if results may indicate a health concern, EPA recommends that systems find out if EPA has proposed an NPDWR or issued a health advisory for that contaminant by calling the Safe Drinking Water Hotline (800-426-4791). EPA considers detects above a proposed MCL or health advisory level to indicate possible health concerns. For such contaminants, EPA recommends that the report include:


(i) The results of the monitoring; and


(ii) An explanation of the significance of the results noting the existence of a health advisory or a proposed regulation.


(f) Compliance with NPDWR. In addition to the requirements of § 141.153(d)(6), the report must note any violation that occurred during the year covered by the report of a requirement listed below, and include a clear and readily understandable explanation of the violation, any potential adverse health effects, and the steps the system has taken to correct the violation.


(1) Monitoring and reporting of compliance data;


(2) Filtration and disinfection prescribed by subpart H of this part. For systems which have failed to install adequate filtration or disinfection equipment or processes, or have had a failure of such equipment or processes which constitutes a violation, the report must include the following language as part of the explanation of potential adverse health effects: Inadequately treated water may contain disease-causing organisms. These organisms include bacteria, viruses, and parasites which can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.


(3) Lead and copper control requirements prescribed by subpart I of this part. For systems that fail to take one or more actions prescribed by §§ 141.80(d), 141.81, 141.82, 141.83 or 141.84, the report must include the applicable language of appendix A to this subpart for lead, copper, or both.


(4) Treatment techniques for Acrylamide and Epichlorohydrin prescribed by subpart K of this part. For systems that violate the requirements of subpart K of this part, the report must include the relevant language from appendix A to this subpart.


(5) Recordkeeping of compliance data.


(6) Special monitoring requirements prescribed by §§ 141.40 and 141.41; and


(7) Violation of the terms of a variance, an exemption, or an administrative or judicial order.


(g) Variances and Exemptions. If a system is operating under the terms of a variance or an exemption issued under § 1415 or 1416 of SDWA, the report must contain:


(1) An explanation of the reasons for the variance or exemption;


(2) The date on which the variance or exemption was issued;


(3) A brief status report on the steps the system is taking to install treatment, find alternative sources of water, or otherwise comply with the terms and schedules of the variance or exemption; and


(4) A notice of any opportunity for public input in the review, or renewal, of the variance or exemption.


(h) Additional information:


(1) The report must contain a brief explanation regarding contaminants which may reasonably be expected to be found in drinking water including bottled water. This explanation may include the language of paragraphs (h)(1) (i) through (iii) or systems may use their own comparable language. The report also must include the language of paragraph (h)(1)(iv) of this section.


(i) The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally-occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity.


(ii) Contaminants that may be present in source water include:


(A) Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.


(B) Inorganic contaminants, such as salts and metals, which can be naturally-occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming.


(C) Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses.


(D) Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, and septic systems.


(E) Radioactive contaminants, which can be naturally-occurring or be the result of oil and gas production and mining activities.


(iii) In order to ensure that tap water is safe to drink, EPA prescribes regulations which limit the amount of certain contaminants in water provided by public water systems. FDA regulations establish limits for contaminants in bottled water which must provide the same protection for public health.


(iv) Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the Environmental Protection Agency’s Safe Drinking Water Hotline (800-426-4791).


(2) The report must include the telephone number of the owner, operator, or designee of the community water system as a source of additional information concerning the report.


(3) In communities with a large proportion of non-English speaking residents, as determined by the Primacy Agency, the report must contain information in the appropriate language(s) regarding the importance of the report or contain a telephone number or address where such residents may contact the system to obtain a translated copy of the report or assistance in the appropriate language.


(4) The report must include information (e.g., time and place of regularly scheduled board meetings) about opportunities for public participation in decisions that may affect the quality of the water.


(5) The systems may include such additional information as they deem necessary for public education consistent with, and not detracting from, the purpose of the report.


(6) Systems required to comply with subpart S. (i) Any ground water system that receives notice from the State of a significant deficiency or notice from a laboratory of a fecal indicator-positive ground water source sample that is not invalidated by the State under § 141.402(d) must inform its customers of any significant deficiency that is uncorrected at the time of the next report or of any fecal indicator-positive ground water source sample in the next report. The system must continue to inform the public annually until the State determines that particular significant deficiency is corrected or the fecal contamination in the ground water source is addressed under § 141.403(a). Each report must include the following elements.


(A) The nature of the particular significant deficiency or the source of the fecal contamination (if the source is known) and the date the significant deficiency was identified by the State or the dates of the fecal indicator-positive ground water source samples;


(B) If the fecal contamination in the ground water source has been addressed under § 141.403(a) and the date of such action;


(C) For each significant deficiency or fecal contamination in the ground water source that has not been addressed under § 141.403(a), the State-approved plan and schedule for correction, including interim measures, progress to date, and any interim measures completed; and


(D) If the system receives notice of a fecal indicator-positive ground water source sample that is not invalidated by the State under § 141.402(d), the potential health effects using the health effects language of Appendix A of subpart O.


(ii) If directed by the State, a system with significant deficiencies that have been corrected before the next report is issued must inform its customers of the significant deficiency, how the deficiency was corrected, and the date of correction under paragraph (h)(6)(i) of this section.


(7) Systems required to comply with subpart Y. (i) Any system required to comply with the Level 1 assessment requirement or a Level 2 assessment requirement that is not due to an E. coli MCL violation must include in the report the text found in paragraph (h)(7)(i)(A) and paragraphs (h)(7)(i)(B) and (C) of this section as appropriate, filling in the blanks accordingly and the text found in paragraphs (h)(7)(i)(D)(1) and (2) of this section if appropriate.


(A) Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful, waterborne pathogens may be present or that a potential pathway exists through which contamination may enter the drinking water distribution system. We found coliforms indicating the need to look for potential problems in water treatment or distribution. When this occurs, we are required to conduct assessment(s) to identify problems and to correct any problems that were found during these assessments.


(B) During the past year we were required to conduct [INSERT NUMBER OF LEVEL 1ASSESSMENTS] Level 1 assessment(s). [INSERT NUMBER OF LEVEL 1 ASSESSMENTS] Level 1 assessment(s) were completed. In addition, we were required to take [INSERT NUMBER OF CORRECTIVE ACTIONS] corrective actions and we completed [INSERT NUMBER OF CORRECTIVE ACTIONS] of these actions.


(C) During the past year [INSERT NUMBER OF LEVEL 2 ASSESSMENTS] Level 2 assessments were required to be completed for our water system. [INSERT NUMBER OF LEVEL 2 ASSESSMENTS] Level 2 assessments were completed. In addition, we were required to take [INSERT NUMBER OF CORRECTIVE ACTIONS] corrective actions and we completed [INSERT NUMBER OF CORRECTIVE ACTIONS] of these actions.


(D) Any system that has failed to complete all the required assessments or correct all identified sanitary defects, is in violation of the treatment technique requirement and must also include one or both of the following statements, as appropriate:


(1) During the past year we failed to conduct all of the required assessment(s).


(2) During the past year we failed to correct all identified defects that were found during the assessment.


(ii) Any system required to conduct a Level 2 assessment due to an E. coli MCL violation must include in the report the text found in paragraphs (h)(7)(ii)(A) and (B) of this section, filling in the blanks accordingly and the text found in paragraphs (h)(7)(ii)(C)(1) and (2) of this section, if appropriate.


(A) E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Human pathogens in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a greater health risk for infants, young children, the elderly, and people with severely compromised immune systems. We found E. coli bacteria, indicating the need to look for potential problems in water treatment or distribution. When this occurs, we are required to conduct assessment(s) to identify problems and to correct any problems that were found during these assessments.


(B) We were required to complete a Level 2 assessment because we found E. coli in our water system. In addition, we were required to take [INSERT NUMBER OF CORRECTIVE ACTIONS] corrective actions and we completed [INSERT NUMBER OF CORRECTIVE ACTIONS] of these actions.


(C) Any system that has failed to complete the required assessment or correct all identified sanitary defects, is in violation of the treatment technique requirement and must also include one or both of the following statements, as appropriate:


(1) We failed to conduct the required assessment.


(2) We failed to correct all sanitary defects that were identified during the assessment that we conducted.


(iii) If a system detects E. coli and has violated the E. coli MCL, in addition to completing the table as required in paragraph (d)(4) of this section, the system must include one or more of the following statements to describe any noncompliance, as applicable:


(A) We had an E. coli-positive repeat sample following a total coliform-positive routine sample.


(B) We had a total coliform-positive repeat sample following an E. coli-positive routine sample.


(C) We failed to take all required repeat samples following an E. coli-positive routine sample.


(D) We failed to test for E. coli when any repeat sample tests positive for total coliform.


(iv) If a system detects E. coli and has not violated the E. coli MCL, in addition to completing the table as required in paragraph (d)(4) of this section, the system may include a statement that explains that although they have detected E. coli, they are not in violation of the E. coli MCL.


[63 FR 44526, Aug. 19, 1998, as amended at 63 FR 69516, Dec. 16, 1998; 64 FR 34733, June 29, 1999; 65 FR 26022, May 4, 2000; 67 FR 1836, Jan. 14, 2002; 71 FR 483, Jan. 4, 2006; 71 FR 65651, Nov. 8, 2006; 78 FR 10348, Feb. 13, 2013; 86 FR 4309, Jan. 15, 2021]


§ 141.154 Required additional health information.

(a) All reports must prominently display the following language: Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (800-426-4791).


(b) Ending in the report due by July 1, 2001, a system which detects arsenic at levels above 0.025 mg/L, but below the 0.05 mg/L, and beginning in the report due by July 1, 2002, a system that detects arsenic above 0.005 mg/L and up to and including 0.010 mg/L:


(1) Must include in its report a short informational statement about arsenic, using language such as: While your drinking water meets EPA’s standard for arsenic, it does contain low levels of arsenic. EPA’s standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water. EPA continues to research the health effects of low levels of arsenic, which is a mineral known to cause cancer in humans at high concentrations and is linked to other health effects such as skin damage and circulatory problems.


(2) May write its own educational statement, but only in consultation with the Primacy Agency.


(c) A system which detects nitrate at levels above 5 mg/l, but below the MCL:


(1) Must include a short informational statement about the impacts of nitrate on children using language such as: Nitrate in drinking water at levels above 10 ppm is a health risk for infants of less than six months of age. High nitrate levels in drinking water can cause blue baby syndrome. Nitrate levels may rise quickly for short periods of time because of rainfall or agricultural activity. If you are caring for an infant you should ask advice from your health care provider.


(2) May write its own educational statement, but only in consultation with the Primacy Agency.


(d) Every report must include the following lead-specific information:


(1) A short informational statement about lead in drinking water and its effects on children. The statement must include the following information:


Lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. [NAME OF UTILITY] is responsible for providing high quality drinking water and removing lead pipes, but cannot control the variety of materials used in plumbing components in your home. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. Before drinking tap water, flush your pipes for several minutes by running your tap, taking a shower, doing laundry or a load of dishes. You can also use a filter certified by an American National Standards Institute accredited certifier to reduce lead in drinking water. If you are concerned about lead in your water and wish to have your water tested, contact [NAME OF UTILITY and CONTACT INFORMATION]. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available at http://www.epa.gov/safewater/lead.


(2) A system may write its own educational statement, but only in consultation with the State.


(e) Community water systems that detect TTHM above 0.080 mg/l, but below the MCL in § 141.12, as an annual average, monitored and calculated under the provisions of § 141.30, must include health effects language for TTHMs prescribed by appendix A.


(f) Beginning in the report due by July 1, 2002, and ending January 22, 2006, a community water system that detects arsenic above 0.010 mg/L and up to and including 0.05 mg/L must include the arsenic health effects language prescribed by appendix A to subpart O of this part.


[63 FR 44526, Aug. 19, 1998, as amended at 63 FR 69475, Dec. 16, 1998; 64 FR 34733, June 29, 1999; 65 FR 26023, May 4, 2000; 66 FR 7064, Jan. 22, 2001; 68 FR 14506, Mar. 25, 2003; 72 FR 57820, Oct. 10, 2007; 86 FR 4309, Jan. 15, 2021]


§ 141.155 Report delivery and recordkeeping.

(a) Except as provided in paragraph (g) of this section, each community water system must mail or otherwise directly deliver one copy of the report to each customer.


(b) The system must make a good faith effort to reach consumers who do not get water bills, using means recommended by the primacy agency. EPA expects that an adequate good faith effort will be tailored to the consumers who are served by the system but are not bill-paying customers, such as renters or workers. A good faith effort to reach consumers would include a mix of methods appropriate to the particular system such as: Posting the reports on the Internet; mailing to postal patrons in metropolitan areas; advertising the availability of the report in the news media; publication in a local newspaper; posting in public places such as cafeterias or lunch rooms of public buildings; delivery of multiple copies for distribution by single-biller customers such as apartment buildings or large private employers; delivery to community organizations.


(c) No later than the date the system is required to distribute the report to its customers, each community water system must mail a copy of the report to the primacy agency, followed within 3 months by a certification that the report has been distributed to customers, and that the information is correct and consistent with the compliance monitoring data previously submitted to the primacy agency.


(d) No later than the date the system is required to distribute the report to its customers, each community water system must deliver the report to any other agency or clearinghouse identified by the primacy agency.


(e) Each community water system must make its reports available to the public upon request.


(f) Each community water system serving 100,000 or more persons must post its current year’s report to a publicly-accessible site on the Internet.


(g) The Governor of a State or his designee, or the Tribal Leader where the tribe has met the eligibility requirements contained in § 142.72 for the purposes of waiving the mailing requirement, can waive the requirement of paragraph (a) of this section for community water systems serving fewer than 10,000 persons. In consultation with the tribal government, the Regional Administrator may waive the requirement of § 141.155(a) in areas in Indian country where no tribe has been deemed eligible.


(1) Such systems must:


(i) Publish the reports in one or more local newspapers serving the area in which the system is located;


(ii) Inform the customers that the reports will not be mailed, either in the newspapers in which the reports are published or by other means approved by the State; and


(iii) Make the reports available to the public upon request.


(2) Systems serving 500 or fewer persons may forego the requirements of paragraphs (g)(1)(i) and (ii) of this section if they provide notice at least once per year to their customers by mail, door-to-door delivery or by posting in an appropriate location that the report is available upon request.


(h) Any system subject to this subpart must retain copies of its Consumer Confidence Report for no less than 3 years.


[63 FR 44526, Aug. 19, 1998, as amended at 65 FR 26023, May 4, 2000]


Appendix A to Subpart O of Part 141—Regulated Contaminants

Contaminant (units)
Traditional MCL in mg/L
To convert for CCR, multiply by
MCL in CCR units
MCLG
Major sources in drinking water
Health effects language
Microbiological contaminants:
Total Coliform Bacteria †MCL (systems that collect ≥40 samples/month) 5% of monthly samples are positive; (systems that collect MCL (systems that collect ≥40 samples/month) 5% of monthly samples are positive; (systems that collect 0Naturally present in the environmentColiforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially-harmful, bacteria may be present. Coliforms were found in more samples than allowed and this was a warning of potential problems.
Total Coliform Bacteria ‡TTTTN/ANaturally present in the environmentUse language found in § 141.153(h)(7)(i)(A)
Fecal coliform and E. coli †000Human and animal fecal wasteFecal coliforms and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.
E. coli ‡Routine and repeat samples are total coliform-positive and either is E. coli-positive or system fails to take repeat samples following E. coli-positive routine sample or system fails to analyze total coliform-positive repeat sample for E. coliRoutine and repeat samples are total coliform-positive and either is E. coli-positive or system fails to take repeat samples following E. coli-positive routine sample or system fails to analyze total coliform-positive repeat sample for E. coli0Human and animal fecal wasteE. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Human pathogens in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a greater health risk for infants, young children, the elderly, and people with severely-compromised immune systems.
Fecal Indicators (enterococci or coliphage)TTTTN/AHuman and animal fecal wasteFecal indicators are microbes whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.
Total organic carbon (ppm)TTTTN/ANaturally present in the environmentTotal organic carbon (TOC) has no health effects. However, total organic carbon provides a medium for the formation of disinfection by products. These byproducts include trihalomethanes (THMs) and haloacetic acids (HAAs). Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects, liver or kidney problems, or nervous system effects, and may lead to an increased risk of getting cancer.
Turbidity (NTU)TTTTN/ASoil runoffTurbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches.
Radioactive contaminants:
Beta/photon emitters (mrem/yr)4 mrem/yr−40Decay of natural and man-made depositsCertain minerals are radioactive and may emit forms of radiation known as photons and beta radiation. Some people who drink water containing beta particle and photon radioactivity in excess of the MCL over many years may have an increased risk of getting cancer.
Alpha emitters (pCi/L)15 pCi/L−150Erosion of natural depositsCertain minerals are radioactive and may emit a form of radiation known as alpha radiation. Some people who drink water containing alpha emitters in excess of the MCL over many years may have an increased risk of getting cancer.
Combined radium (pCi/L)5 pCi/L−50Erosion of natural depositsSome people who drink water containing radium-226 or -228 in excess of the MCL over many years may have an increased risk of getting cancer.
Uranium (pCi/L)30 µg/L−300Erosion of natural depositsSome people who drink water containing uranium in excess of the MCL over many years may have an increased risk of getting cancer and kidney toxicity.
Inorganic contaminants:
Antimony (ppb).006100066Discharge from petroleum refineries; fire retardants; ceramics; electronics; solderSome people who drink water containing antimony well in excess of the MCL over many years could experience increases in blood cholesterol and decreases in blood sugar.
Arsenic (ppb)
1 0.010		1000
1 10.
1 0		Erosion of natural deposits; Runoff from orchards; Runoff from glass and electronics production wastesSome people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer.
Asbestos (MFL)7 MFL77Decay of asbestos cement water mains; Erosion of natural depositsSome people who drink water containing asbestos in excess of the MCL over many years may have an increased risk of developing benign intestinal polyps.
Barium (ppm)222Discharge of drilling wastes; Discharge from metal refineries; Erosion of natural depositsSome people who drink water containing barium in excess of the MCL over many years could experience an increase in their blood pressure.
Beryllium (ppb).004100044Discharge from metal refineries and coal-burning factories; Discharge from electrical, aerospace, and defense industriesSome people who drink water containing beryllium well in excess of the MCL over many years could develop intestinal lesions
Bromate (ppb).0101000100By-product of drinking water disinfectionSome people who drink water of containing bromate in excess of the MCL over many years may have an increased risk of getting cancer.
Cadmium (ppb).005100055Corrosion of galvanized pipes; Erosion of natural deposits; Discharge from metal refineries; Runoff from waste batteries and paintsSome people who drink water containing cadmium in excess of the MCL over many years could experience kidney damage.
Chloramines (ppm)MRDL = 4MRDL = 4MRDLG = 4Water additive used to control microbesSome people who use water containing chloramines well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chloramines well in excess of the MRDL could experience stomach discomfort or anemia.
Chlorine (ppm)MRDL = 4MRDL = 4MRDLG = 4Water additive used to control microbesSome people who use water containing chlorine well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chlorine well in excess of the MRDL could experience stomach discomfort.
Chlorine dioxide (ppb)MRDL = .81000MRDL = 800MRDLG = 800Water additive used to control micorbesSome infants and young children who drink water chlorine dioxide in excess of the MRDL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of the MRDL. Some people may experience anemia.
Chlorite (ppm)110.8By-product of drinking water disinfectionSome infants and young children who drink water containing chlorite in excess of the MCL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorite in excess of the MCL. Some people may experience anemia.
Chromium (ppb).11000100100Discharge from steel and pulp mills; Erosion of natural depositsSome people who use water containing chromium well in excess of the MCL over many years could experience allergic dermatitis.
Copper (ppm)AL = 1.3AL = 1.31.3Corrosion of household plumbing systems; Erosion of natural depositsCopper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney damage. People with Wilson’s disease should consult their personal doctor.
Cyanide (ppb).21000200200Discharge from steel/metal factories; Discharge from plastic and fertilizer factoriesSome people who drink water containing cyanide well in excess of the MCL over many years could experience nerve damage or problems with their thyroid.
Fluoride (ppm)444Erosion of natural deposits; Water additive which promotes strong teeth; Discharge from fertilizer and aluminum factoriesSome people who drink water containing fluoride in excess of the MCL over many years could get bone disease, including pain and tenderness of the bones. Fluoride in drinking water at half the MCL or more may cause mottling of children’s teeth, usually in children less than nine years old. Mottling, also known as dental fluorosis, may include brown staining and/or pitting of the teeth, and occurs only in developing teeth before they erupt from the gums.
LeadAL = .0151000AL = 150Corrosion of household plumbing systems, Erosion of natural deposits.Exposure to lead in drinking water can cause serious health effects in all age groups. Infants and children can have decreases in IQ and attention span. Lead exposure can lead to new learning and behavior problems or exacerbate existing learning and behavior problems. The children of women who are exposed to lead before or during pregnancy can have increased risk of these adverse health effects. Adults can have increased risks of heart disease, high blood pressure, kidney or nervous system problems.
Mercury [inorganic] (ppb).002100022Erosion of natural deposits; Dis charge from refineries and factories; Runoff from landfills; Runoff from croplandSome people who drink water containing inorganic mercury well in excess of the MCL over many years could experience kidney damage.
Nitrate (ppm)101010Runoff from fertilizer use; Leaching from septic tanks, sew age; Erosion of natural depositsInfants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome.
Nitrite (ppm)111Runoff from fertilizer use; Leaching from septic tanks, sew age; Erosion of natural depositsInfants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome.
Selenium (ppb).0510005050Discharge from petroleum and metal refineries; Erosion of natural deposits; Discharge from minesSelenium is an essential nutrient. However, some people who drink water containing selenium in excess of the MCL over many years could experience hair or fingernail losses, numbness in fingers or toes, or problems with their circulation.
Thallium (ppb).002100020.5Leaching from ore-processing sites; Discharge from electronics, glass, and drug factoriesSome people who drink water containing thallium in excess of the MCL over many years could experience hair loss, changes in their blood, or problems with their kidneys, intestines, or liver.
Synthetic organic contaminants including pesticides and herbicides:
2,4-D (ppb).0710007070Runoff from herbicide used on row cropsSome people who drink water containing the weed killer 2,4-D well in excess of the MCL over many years could experience problems with their kidneys, liver, or adrenal glands.
2,4,5-TP [Silvex](ppb).0510005050Residue of banned herbicideSome people who drink water containing silvex in excess of the MCL over many years could experience liver problems.
AcrylamideTTTT0Added to water during sewage/wastewater treatmentSome people who drink water containing high levels of acrylamide over a long period of time could have problems with their nervous system or blood, and may have an increased risk of getting cancer.
Alachlor (ppb).002100020Runoff from herbicide used on row cropsSome people who drink water containing alachlor in excess of the MCL over many years could have problems with their eyes, liver, kidneys, or spleen, or experience anemia, and may have an increased risk of getting