Code of Massachusetts Regulations
310 CMR - DEPARTMENT OF ENVIRONMENTAL PROTECTION
Title 310 CMR 22.00 - Drinking Water
Section 22.07A - Synthetic Organic Chemicals (SOC) Sampling and Analytical Requirements

Universal Citation: 310 CMR 22.00 MA Code of Regs 22.07A

Current through Register 1531, September 27, 2024

(1) Synthetic Organic Chemicals MCLs. The following maximum contaminant levels for organic contaminants apply to community water systems and non-transient, non-community water systems.

CAS No.

Contaminant

MCL (mg/l)

(a)

15972-60-8

Alachlor

0.002

(b)

Reserved

(c)

Reserved

(d)

Reserved

(e)

1912-24-9

Atrazine

0.003

(f)

1563-66-2

Carbofuran

0.04

(g)

57-74-9

Chlordane

0.002

(h)

96-12-8

Dibromochloropropane

0.0002

(i)

94-75-7

2,4-D

0.07

(j)

72-20-80

Endrin

0.002

(k)

106-93-4

Ethylene dibromide

0.00002

(l)

76-44-8

Heptachlor

0.0004

(m)

1024-57-3

Heptachlor epoxide

0.0002

(n)

58-89-9

Lindane

0.0002

(o)

72-43-5

Methoxychlor

0.04

(p)

1336-36-3

Polychlorinated biphenyls

0.0005

(q)

87-86-5

Pentachlorophenol

0.001

(r)

8001-35-2

Toxaphene

0.003

(s)

93-72-1

2,4,5-TP

0.05

(t)

50-32-8

Benzo(a)pyrene

0.0002

(u)

75-99-0

Dalapon

0.2

(v)

103-23-1

Di(2-ethylhexyl) adipate

0.4

(w)

117-81-7

Di(2-ethylhexyl) phthalate

0.006

(x)

88-85-7

Dinoseb

0.007

(y)

85-00-7

Diquat

0.02

(z)

145-73-3

Endothall

0.1

(aa)

1071-53-6

Glyphosate

0.7

(bb)

118-74-1

Hexachlorobenzene

0.001

(cc)

77-47-4

Hexachlorocyclopentadiene

0.05

(dd)

23135-22-0

Oxamyl (Vydate)

0.2

(ee)

1918-02-1

Picloram

0.5

(ff)

122-34-9

Simazine

0.004

(gg)

1746-01-6

2,3,7,8-TCDD(Dioxin)

3x10-8

(2) SOC Sampling Requirements. Beginning with the initial compliance period, analysis of the contaminants listed in 310 CMR 22.07A(1)(a) through (gg) for the purposes of determining compliance with the maximum contaminant level shall be conducted as follows:

(a) SOC Ground Water Monitoring Protocols. 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 (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.

(b) SOC Surface Water Monitoring Protocols. Surface water systems [Note: For purposes of 310 CMR 22.07A(2)(b), surface water systems include systems with a combination of surface and ground sources.) 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 (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.

(c) Multiple Sources. 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).

(d) Consecutive System Monitoring. Public water systems that obtain water from another public water system are exempt from conducting compliance monitoring for the purchased portion of the system for the organic chemicals (SOC) under 310 CMR 22.07A, provided that the system from which the water is obtained has conducted the analyses required under 310 CMR 22.07A, unless otherwise specified by the Department.

(3) SOC Monitoring Frequency.

(a) Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in 310 CMR 22.07A(1) during each compliance period beginning with the compliance period starting January 1, 1993.

(b) 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.

(c) 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.

(4) SOC Sampling Waivers. Each community and non-transient water system may apply to the Department for a waiver from the requirement of 310 CMR 22.07A(3). A system must reapply for a waiver for each compliance period.

Basis of an SOC Sampling Waiver. The Department 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 Department reveals no previous use of the contaminant within the watershed or Zone II or IWPA, 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.

(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. 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.

(c) The environmental persistence and transport of the pesticide or PCBs.

(d) 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 and other protective measures considered relevant by the Department.

(e) Elevated nitrate levels at the water supply source.

(f) Use of PCBs in equipment used in the production, storage, or distribution of water (i.e., PCBs used in pumps, transformers, etc.).

(5) Detection of an SOC. If an organic contaminant listed in 310 CMR 22.07A(1) is detected (as defined by 310 CMR 22.07A(16) in any sample, then:

(a) Each system shall report to the Department within seven days and shall monitor quarterly at each sampling point which resulted in a detection.

(b) The Department may decrease the quarterly monitoring requirement specified in 310 CMR 22.07A(5)(a) provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the Department 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.

(c) After the Department determines the system is reliably and consistently below the maximum contaminant level the Department may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter that previously yielded the highest analytical result.

(d) Systems which have three consecutive annual samples with no detection of a contaminant may apply to the Department for a waiver as specified in 310 CMR 22.07A(4).

(e) If monitoring results in detection of one or more of certain related contaminants (heptachlor, heptachlor epoxide), then subsequent monitoring shall analyze for all related contaminants.

(6) MCL Violation and Reliably/consistently below the MCL. Systems which violate the requirements of 310 CMR 22.07A(1) as determined by 310 CMR 22.07A(9) must monitor quarterly. After a minimum of four quarterly samples show the system is in compliance and the Department determines the system is reliably and consistently below the MCL, as specified in 310 CMR 22.07A(9), the system shall monitor at the frequency specified in 310 CMR 22.07A(5)(c).

(7) SOC Confirmation Sampling. The Department may require a confirmation sample for positive or negative results. If a confirmation sample is required by the Department, the result must be averaged with the first sampling result and the average used for the compliance determination as specified by 310 CMR 22.07A(9). The Department has discretion to delete results of obvious sampling errors from this calculation.

(8) Composite SOC Sampling. The total number of samples which must be analyzed may be reduced by compositing samples. 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 and none of the samples to be composited are representative of multiple sources. Compositing of samples must be approved by the Department and must be done in the laboratory and analyzed within the holding times specified by EPA-814B-92-002, Change 2 - September 1992 Manual for the Certification of Laboratories Analyzing Drinking Water, third edition. Compositing of sources with previous detections greater than the detection limit is not allowed, unless otherwise authorized by the Department.

(a) If the concentration in the composite sample exceeds the detection limit for one or more contaminants listed in 310 CMR 22.07A(1), then a follow-up sample must be taken and analyzed from each sampling point included in the company within 14 days after completion of the composite analysis or before the holding time of the initial sample is exceeded, whichever is sooner.

(b) If duplicates of the original sample taken from each sampling point used in the composite are available, the system may use these duplicates instead of resampling. The duplicate must be analyzed and the results reported to the Department within 14 days of collection.

(c) If the population served by the system is >3,300 persons, then compositing may only be permitted by the Department at sampling points within a single system. In systems serving <=3,300 persons, the Department may permit compositing among different systems provided the 5-sample limit is maintained.

(9) SOC Compliance Calculations. Compliance with 310 CMR 22.07A(1) 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.

(a) Greater than Annual. For systems monitoring more than once per year, compliance with the MCL is determined by a running annual average at each sampling point.

(b) Annual or Less. Each supplier of water monitoring annually or less frequently whose sample result exceeds the regulatory detection level as defined by 310 CMR 22.07A(16) must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling.

(c) 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.

(d) If a supplier of water fails to collect the required number of samples, compliance will be based on the total number of samples collected.

(e) If a sample result is less than the detection limit, zero will be used to calculate the annual average.

(f) Average Exceeding SOC MCLs. When the average of four analyses made pursuant to 310 CMR 22.07A(5), 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 report to the Department pursuant to 310 CMR 22.15 and give public notice to the public pursuant to 310 CMR 22.16. Monitoring after public notification shall be at a frequency designated by the Department and shall continue until the maximum contaminant level has not been exceeded in two successive samples or until a monitoring schedule as condition to variance, exemption or enforcement action shall become effective.

(10) SOC Analytical Methods. Analysis for the contaminants listed in 310 CMR 22.07A(1) shall be conducted using the following EPA methods or their equivalent as approved by EPA. Methods 508A and 515.1 are contained 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, PB92-27703, PB95-261616 and PB95-104774 (respectively), U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161. The phone number is 800-553-6847. The phone number is 513-569-7586. Method 6610 is contained in Standard Methods for the Examination of Water and Wastewater 18th Edition Supplement, 1994, or with the 19th edition (1995) or 20th edition (1998), any of these three editions may be used. Method 6651 is contained in Standard Methods for the Examination of Water and Wastewater 18th Edition, (1992), 19th edition (1995), or 20th edition (1998); any of these three editions may be used. The APHA documents are available from American Public Health Association, 1015 Fifteenth Street NW, Wash., D.C. 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 Methods 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 methods may be used. EPA Methods 515.4, "Determination of Chlorinated Acids in Drinking Water by Liquid-Liquid Microextraction, Derivatization and Fast Gas Chromatrography with Electron Capture Detection", Revision 1.0, April 2000, EPA/815/B-00/001 and EPA Methods 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 [File Link Not Available]. 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-methylcarbamoyloximes and N-methylcarbamates in Water by Direct Aqueous Injection HPLC with Postcolumn Derivatization", Revision 1., September 2001, EPA 815-B-01-002, can be accessed and downloaded directly online at http://www.epa.gov/safewater/methods/sourcult.htnml.

Contaminant

EPA Method

SM

ASTM

Other

2,3,7,8-TCDD(dioxin)

1613

2,4-D3 (as acid, salts and esters)

515.2, 555, 515.1, 515.3, 515.4

D5317-93,98 (Reapproved 2003).

2,4,5-TP3 (Silvex)

515.2, 555, 515.1, 515.3, 515.4

D5317-93, 98 (Reapproved 2003).

Alachor1

505, 507, 525.2, 508.1, 551.1

Atrazine1

505, 507, 525.2, 508.1, 551.1

Syngenta AG-6254

Benzo(a)pyrene

525.2, 550, 550.1

Carbofuran

531.1, 531.2

6610

Chlordane

505, 508, 525.2, 508.1

Dalapon

552.1, 515.1, 515.3, 552.2, 515.4

Di(2-ethylhexyl)adipate

506, 525.2

Di(2-ethylhexyl)phthalate

506, 525.2

Dibromochloropropane (DBCP)

504.1, 551.1

Dinoseb3

515.2, 555, 515.1, 515.3, 515.4

Diquat

549.2

Endothall

548.1

Endrin

505, 508, 525.2, 508.1, 551.1

Ethylene dibromide (EDB)

504.1, 551.1

6651

Glyphosate

547

Heptachlor

505, 508, 525.2, 508.1, 551.1

Heptachlor Epoxide

505, 508, 525.2, 508.1, 551.1

Hexachlorobenzene

505, 508, 525.2, 508.1, 551.1

Hexachloro-cyclopentadiene

505, 508, 525.2, 508.1, 551.1

Lindane

505, 508, 525.2, 508.1, 551.1

Methoxychlor

505, 508, 525.2, 508.1, 551.1

Oxamyl

531.1, 531, 2

6610

PCBs(as decachlorobiphenyl)2

508A

PCBs (as Aroclors)2

505, 508, 508.1, 525.2

Pentachlorophenol

515.2, 525.2, 555, 515.1, 515.3, 515.4

D5317-93, 98 (Reapproved 2003).

Picloram3

515.2, 555, 515.1, 515.3, 515.4

D5317-93, 98 (Reapproved 2003).

Simazine1

505, 507, 525.2, 508.1, 551.1

Toxaphene

505, 508, 508.1, 525.2

Footnotes

1 Substitution of the detector specified in Methods 505, 507, 508, or 508.1 for the purpose of achieving lower detection limits is allowed as follows. Either an electron capture or nitrogen phosphorus detector may be used provided all regulatory requirements and quality control criteria are met.

2 PCBs are qualitatively identified as Arolcolrs 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.

3 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 Methods D5317-93,98 (Reapproved 2003).

4 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 1/2 the maximum contaminant level (MCL) (in other words, greater than 0.0015mg/L or 1.5 ug/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.

(11) Analysis for PCBs shall be conducted as follows:

(a) Each system that monitors for PCBs shall analyze each sample using either Method 508.1, 525.2, 508 or 505. The mean of the method detection limits of all Aroclors shall be 0.00025mg/l except for Aroclor 1221 which is 0.02 mg/l. Users of Method 505 may have more difficulty in achieving the required Aloclor detection limits than using methods 508.1, 525.2 or 508.
1. A lab may conduct a scan for Aroclors using any one of the four methods mentioned in 310 22.07A(11)(a).

2. A lab that is certified for any of the four methods listed in 310 22.07A(11)(a) is eligible to conduct the scan for Aroclors.

(b) If PCBs (as one of seven Aroclors) are detected as designated in 310 CMR 22.07A(11)(a) the system shall reanalyze the sample using Method 508A to quantitate PCBs (as decachlorobiphenyl).

(c) Compliance with the PCB MCL shall be determined based upon the quantitative results of analyses using Method 508A.

(12) Grandfathered SOC Data: The Department may allow the use of monitoring data collected after January 1, 1990, for purposes of satisfying the initial monitoring requirement of 310 CMR 22.07A(2), if in the opinion of the Department, the data are generally consistent with the requirements of 310 CMR 22.07A(2). A single sample rather than four quarterly samples may be allowed by the Department to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.

(13) Increased SOC Sampling: The Department 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).

(14) Enforcement: The Department has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.

(15) Designated Sampling Schedules: Each public water system shall monitor at the time designated by the Department within each compliance period.

(16) SOC Detection Limits: Detection as used in 310 CMR 22.07A(5) shall be defined as greater than or equal to the following concentrations for each contaminant. (Please refer to the Guidelines and Policies for further information regarding detection limits).

SOC DETECTION LIMITS

Contaminant

Detection Limit mg/l

Alachlor

0.0002

Aldicarb

0.0005

Aldicarb sulfoxide

0.0005

Aldicarb sulfone

0.0008

Atrazine

0.0001

Benzo(a)pyrene

0.00002

Carbofuran

0.0009

Chlordane

0.0002

Dalapon

0.001

Dibromochloropropane (DBCP)

0.00002

Di (2-ethythexyl) adipate

0.0006

Di (2-ethylhexyl) phthalate

0.0006

Dinoseb

0.0002

Diquat

0.0004

2,4-D

0.0001

Endothall

0.009

Endrin

0.00001

Ethylene dibromide (EDB)

0.00001

Glyphosate

0.006

Heptachlor

0.00004

Heptachlor epoxide

0.00002

Hexachlorobenzene

0.0001

Hexachlorocyclopentadiene

0.0001

Lindane

0.00002

Methoxychlor

0.0001

Oxamyl

0.002

Picloram

0.0001

Polychlorinated biphenyls (PCBs) (as decachlorobiphenyl)

0.0001

Pentachlorophenol

0.00004

Simazine

0.00007

Toxaphene

0.001

2,3,7,8-TCDD (Dioxin)

0.000000005

2,4,5-TP (Silvex)

0.0002

(17) SYNTHETIC ORGANIC BATs. The EPA Administrator, pursuant to the federal Safe Drinking Water Act, § 1412, has identified as indicated in the Table below either 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 310 CMR 22.07A(1):

BAT FOR ORGANIC CONTAMINANTS LISTED IN 310 CMR 22.07A(1)

CAS #

Chemical

GAC

PTA

OX

15972-60-8

Alachlor

X

116-06-3

Aldicarb

X

1646-88-4

Aldicarb sulfone

X

1646-87-3

Aldicarb sulfoxide

X

1912-24-9

Atrazine

X

50-32-8

Benzo[a)pyrene

X

1563-66-2

Carbofuran

X

57-74-9

Chlordane

X

75-99-0

Dalapon

X

96-12-8

Dibromochloropropane (DBCP)

X

X

75-09-2

Dichloreomethane

X

103-23-1

Di (2-ethylhexyl) adipate

X

X

117-81-7

Di (2-ethylhexyl) phthalate

X

88-85-7

Dinoseb

X

85-00-7

Diquat

X

94-75-7

2,4-D

X

72-20-8

Endrin

X

145-73-3

Endothall

X

106-93-4

Ethylene Dibromide (EDB)

X

X

1071-583-6

Glyphosate

X

76-44-8

Heptachlor

X

1024-57-3

Heptachlor epoxide

X

118-74-1

Hexachlorobenzene

X

77-47-3

Hexachlorocyclopentadiene

X

X

58-89-9

Lindane

X

72-43-5

Methoxychlor

X

1336-36-3

Polychlorinated biphenyls(PCB)

X

23135-22-0

Oxamyl (Vydate)

X

87-86-5

Pentachlorophenol

X

1918-02-1

Picloram

X

93-72-1

2,4,5-TP (Silvex)

X

122-34-9

Simazine

X

120-82-1

1,2,4-Trichlorobenzene

X

X

79-00-5

1,1,2-Trichloroethane

X

X

1746-01-6

2,3,7,8-TCDD(Dioxin)

X

8001-35-2

Toxaphene

X

X

(18) New Systems/Sources. Each new supplier of water or supplier of water that uses a new source of water that begins operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the Department. The supplier of water must also comply with the initial sampling frequencies specified by the Department to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in 310 CMR 22.07A.

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