Code of Massachusetts Regulations
310 CMR - DEPARTMENT OF ENVIRONMENTAL PROTECTION
Title 310 CMR 42.00 - Certification And Operation Of Environmental Analysis Laboratories
Section 42.20 - Potable Water

Universal Citation: 310 MA Code of Regs 310.42

Current through Register 1531, September 27, 2024

(1) To receive certification to conduct analyses for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, nitrite, selenium, and thallium the laboratory must:

(a) Analyze Proficiency Test samples provided by EPA, the Department, or by a Department-approved third party; and

(b) Achieve quantitative results on the analyses that are within the following acceptance limits:

Contaminant

Acceptance Limit

Antimony

± 30% at >= 0.006 mg/L

Arsenic

+ 30% at >= 0.003 mg/L

Asbestos

2 standard deviations based on study statistics

Barium

± 15% at >= 0.15 mg/L

Beryllium

±15% at >= 0.001 mg/L

Cadmium

± 20% at >= 0.002 mg/L

Chromium

± 15% at >= 0.01 mg/L

Cyanide

± 25% at >= 0.1 mg/L

Fluoride

± 10% at 1 to 10 mg/L

Mercury

± 30% at >= 0.0005 mg/L

Nickel

± 15% at >= 0.01 mg/L

Nitrate

± 10% at >= 0.4 mg/L

Nitrite

± 15% at >= 0.4 mg/L

Selenium

± 20% at >= 0.01 mg/L

Thallium

± 30% at >=0.002 mg/L

(2) To receive certification to conduct analyses for the contaminants in 310 CMR 42.20(2)(b), the laboratory must:

(a) Analyze Proficiency Test samples provided by EPA, the Department, or by a third party with the approval of the Department; and

(b) Achieve quantitative results on the analyses that are within the following acceptance limits:

Contaminant

Acceptance Limit (percent)

1,2-Dibromo-3-chloropropane (DBCP)

± 40

1,2-Dibromoethane (EDB)

± 40

Alachlor

± 45

Atrazine

± 45

Benzo[a]pyrene

2 standard deviations

Carbofuran

± 45

Chlordane

± 45

Dalapon

2 standard deviations

Di(2-ethylhexyl)adipate

2 standard deviations

Di(2-ethylhexyl)phthalate

2 standard deviations

Dinoseb

2 standard deviations

Diquat

2 standard deviations

Endothall

2 standard deviations

Endrin

± 30

Glyphosate

2 standard deviations

Heptachlor

± 45

Heptachlor epoxide

± 45

Hexachlorobenzene

2 standard deviations

Hexachlorocyclopentadiene

2 standard deviations

Lindane

± 45

Methoxychlor

± 45

Oxamyl(Vydate)

2 standard deviations

Polychlorinated biphenyls (as decachlorobiphenyl)

0-200

Picloram

2 standard deviations

Simazine

2 standard deviations

Toxaphene

+ 45

Aldicarb

2 standard deviations

Aldicarb sulfoxide

2 standard deviations

Aldicarb sulfone

2 standard deviations

Pentachlorophenol

± 50

2,4-Dichlorophenoxyacetic acid (2,4-D)

± 50

2-(2,4,5-Trichlorophenoxy)propionic acid (2,4,5-TP) (Silvex)

± 50

(3) To receive certification to conduct analyses for benzene, carbon tetrachloride, 1,2-dichloroethane, 1,1-dichloroethylene, p-dichlorobenzene, 1,1,1-trichloroethane, trichloroethylene, o-dichlorobenzene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,2-dichloropropane, ethylbenzene, monochlorobenzene, styrene, tetrachloroethylene, toluene, xylenes (total), dichloromethane, 1,2,4-trichlorobenzene, and 1,1,2-trichloroethane, the laboratory must:

(a) Analyze Proficiency Test (PT) samples provided by EPA, the Department, or by a Department-approved third party;

(b) Achieve the quantitative acceptance limits on the analyses performed under 310 CMR 42.20(3)(a) for at least 80% of the regulated organic chemicals listed at 310 CMR 42.20(3);

(c) Achieve quantitative results on the analyses performed under 310 CMR 42.20(3)(a) that are within ± 20% of the actual amount of the substances in the PT sample when the actual amount is greater than or equal to 0.010 mg/L;

(d) Achieve quantitative results on the analyses performed under 310 CMR 42.20(3)(a) that are within ± 40% of the actual amount of the substances in the PT sample when the actual amount is less than 0.010 mg/L; and

(e) Achieve a method detection limit of 0.0005 mg/L according to the procedures in Appendix B of 40 CFR Part 136.

(4) To receive certification for vinyl chloride, the laboratory must:

(a) Analyze Proficiency Test (PT) samples provided by EPA, the Department, or by a Department-approved third party;

(b) Achieve quantitative results on the analyses performed under 310 CMR 42.20(4)(a) that are within ± 40% of the actual amount of vinyl chloride in the PT sample;

(c) Achieve a method detection limit of 0.0005 mg/L according to procedures in 40 CFR Part 136: Appendix B; and

(d) Obtain certification for the contaminants listed in 310 CMR 42.20(3).

(5) To receive certification for total trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, and bromoform), haloacetic acids (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid, known collectively as HAA5), bromate, and chlorite, the laboratory must:

(a) Analyze Proficiency Test (PT) samples approved by the Department at least once each calendar year by each method for which the laboratory desires certification;

(b) Achieve quantitative results within the acceptable limit for each analyte included in each PT sample and, for haloacetic acids, on a minimum of 80% of the analytes included in each PT sample. The acceptance limit is defined as ± 20% of the true value for each of the trihalomethanes; ± 40% of the true value for each of the haloacetic acids; ± 30% of the true value for chlorite; and ± 30% of the true value for bromate;

(c) Report quantitative data for concentrations at least as low as the regulatory minimum reporting level of 0.0010 mg/L for each of the trihalomethanes, 0.0020 mg/L for monochloroacetic acid, 0.0010 mg/L for dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid, 0.020 mg/L for chlorite, and 0.0050 mg/L for bromate (0.0010 mg/L for laboratories using EPA Methods 317 Revision 2.0, 326.0 or 321.8);

(d) Use calibration curves for the analysis of trihalomethanes, haloacetic acids, bromate, and chlorite that 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 five 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; and

(e) When adding the individual trihalomethane or haloacetic acid concentrations in order to calculate the total trihalomethane or HAA5 concentrations, respectively, use a zero for any analytical result that is less than the MRL concentration for that particular analyte.

(6) To receive certification to conduct analyses for perchlorate, the laboratory must:

(a) Analyze PT samples approved by the Department;

(b) Achieve quantitative results within the acceptable limit for this analyte in each PT sample. The acceptance limit is defined as the 95% confidence interval calculated around the mean of the PT study data;

(c) Use analytical methods acceptable to the Department; and

(d) Comply with specific Department policies regarding quality assurance/quality control and data reporting procedures for this analyte.

(7) To receive certification to conduct analyses for 1,4-dioxane, the laboratory must:

(a) Analyze PT samples approved by the Department;

(b) Achieve quantitative results within the acceptable limit for this analyte in each PT sample. The acceptance limit is defined as the 95% confidence interval calculated around the mean of the PT study data; and

(c) Use analytical methods, quality assurance/quality control protocols, and data reporting procedures acceptable to the Department.

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