Code of Massachusetts Regulations
310 CMR - DEPARTMENT OF ENVIRONMENTAL PROTECTION
Title 310 CMR 22.00 - Drinking Water
Section 22.07B - Maximum Contaminant Levels (MCLs) for Volatile Organic Compounds (VOC)

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

Current through Register 1531, September 27, 2024

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

CAS No.

Contaminant

MCL (mg/l)

(a)

75-01-4

Vinyl chloride

0.002

(b)

71-43-2

Benzene

0.005

(c)

56-23-5

Carbon tetrachloride

0.005

(d)

107-06-2

1,2-Dichloroethane

0.005

(e)

79-01-6

Trichloroethylene

0.005

(f)

106-46-7

para-Dichlorobenzene

0.005

(g)

75-35-4

1,1-Dichloroethylene

0.007

(h)

71-55-6

1,1,1-Trichloroethane

0.2

(i)

156-59-2

cis-1,2-Dichloroethylene

0.07

(j)

78-87-5

1,2-Dichloropropane

0.005

(k)

100-41-4

Ethylbenzene

0.7

(l)

108-90-7

Monochlorobenzene

0.1

(m)

95-50-1

o-Dichlorobenzene

0.6

(n)

100-42-5

Styrene

0.1

(o)

127-18-4

Tetrachloroethylene

0.005

(p)

108-88-3

Toluene

1

(q)

156-60-5

trans-1,2-Dichloroethylene

0.1

(r)

1330-20-7

Xylenes (total)

10

(s)

75-09-2

Dichloromethane

0.005

(t)

120-82-1

1,2,4-Trichlorobenzene

0.07

(u)

79-00-5

1,1,2-Trichloroethane

0.005

(2) VOC Sampling Requirements. Beginning with the initial compliance period analysis of the contaminants listed in 310 CMR 22.07B(1) for the purpose of determining compliance with the maximum contaminant level the monitoring shall be conducted as follows:

(a) VOC 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). If conditions warrant, the Department may designate additional sampling points within the distribution system or at the consumer's tap which more accurately determines consumer exposure. Each sample must be taken at the same sampling point unless the Department determine that conditions make another sampling point more representative of each source, treatment plant, or within the distribution system.

(b) VOC Surface Water Monitoring Protocols. 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 (sampling point). If conditions warrant, the Department may designate additional sampling points within the distribution system or at the consumer's tap which more accurately determines consumer exposure. 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.

(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) Initial VOCs Sampling Frequency. Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in 310 CMR 22.07B(1) during each compliance period, beginning in the initial compliance period.

(e) VOC Grandfathered Data with No Detects - Reduced Monitoring. If the initial monitoring for contaminants listed in 310 CMR 22.07B(1) as allowed in 310 CMR 22.07B(10), has been completed by December 31, 1992, and the system did not exceed the detection levels in 310 CMR 22.07B(4) any contaminant listed in 310 CMR 22.07B(1), then each ground and surface water system shall take one sample annually beginning with the initial compliance period.

(f) Reduced VOC Sampling - Annually. Groundwater and surface water systems which do not detect one of the contaminants listed in 310 CMR 22.07B(1) after conducting the initial round of monitoring required in 310 CMR 22.07B(2)(a) and (b) shall take one sample annually.

(3) VOC Sampling Waivers. Each community and non-transient non-community system which does not detect a contaminant listed in 310 CMR 22.07B(1) may apply to the Department for a waiver from the requirements of 310 CMR 22.07B(2)(d), (f) and (10) after completing the initial monitoring. (For the purposes of 310 CMR 22.07B, detection is defined as >=0.0005 mg/l.) A waiver shall be effective for no more than three years (one compliance period).

(a) Basis of a VOC Sampling Waiver. A Department may grant a waiver after evaluating the following factor(s):
1. 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 II or IWPA, a waiver may be granted.

2. 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 and other protective measures considered relevant by the Department. 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.

(b) VOC Waiver Requirements for GW Systems. 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 one compliance period or three years) and update its vulnerability assessment considering the factors listed in 310 CMR 22.07B(3)(a). Based on this vulnerability assessment the Department must reconfirm that the system is non-vulnerable. If the Department 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 310 CMR 22.07B(10)(a).

(c) VOC Waiver Requirements for SW Systems. Each community and non-transient non-community surface water system which does not detect a contaminant listed in 310 CMR 22.07B(1) may apply to the Department for a waiver from the requirements of 310 CMR 22.07B(2)(a) after completing the initial monitoring. Systems meeting this criteria must be determined by the Department 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 Department.

(4) Detection of a VOC.

(a) If a contaminant listed in 310 CMR 22.07B(1) is detected at a level exceeding 0.0005 mg/l in any sample, then:
1. The system shall report to the Department within seven days and shall monitor for the contaminants listed in 310 CMR 22.07B quarterly at each sampling point which resulted in a detection.

2. The Department may decrease the quarterly monitoring requirement specified in 310 CMR 22.07B(4)(a)1. 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.

3. If the Department determines that the system is reliably and consistently below the MCL, the Department may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter(s) which previously yielded the highest analytical result or as specified by the Department.

(b) Detection of a VOC Other than Those Listed in 310 CMR 22.07B(1). Systems which detect any VOC contaminants at any level shall report the results to the Department.

(c) VOCs Reliably and Consistently below the MCL. Systems which violate the requirements of 310 CMR 22.07B(1), as determined by 310 CMR 22.07B(7), must monitor quarterly. After a minimum of four consecutive quarterly samples which show the system is in compliance as specified in 310 CMR 22.07B(7) the system demonstration and the Department determines that the system is reliably and consistently below the maximum contaminant level, the system may monitor at the frequency and time specified in 310 CMR 22.07B(4)(a)3.

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

(6) VOC Composite Samples. The total number of samples a system must analyze may be reduced, with the Department's approval, by the compositing of 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 done in the laboratory and analyzed within 14 days of sample collection. Compositing of sources with previous detections exceeding the detection limit is not allowed, unless otherwise authorized by the Department. If duplicates of the original samples taken from each sampling point used in the composit samples are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the Department within 14 days after completing the analyses of the composited samples, provided the holding times of the samples has not been exceeded.

(a) If the concentration in the composite sample is >=0.0005 mg/l for any contaminant listed in 310 CMR 22.07B(1), then a follow-up sample must be taken and analyzed within 14 days from each sampling point included in the composite.

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

(c) Compositing will be permitted at sampling points within a single system, unless the population served by the system is <=3,300 persons. In systems serving <=3,300 persons, compositing is permitted with the Department's approval among different systems provided the five-sample limit is maintained.

(d) Compositing samples prior to GC analysis.
1. Add 5 ml or equal larger amounts of each sample (up to five samples are allowed) to a 25 ml glass syringe. Special precautions must be made to maintain zero headspace in the syringe.

2. The samples must be cooled at 4°C during this step to minimize volatilization losses.

3. Mix well and draw out a 5-ml aliquot for analysis.

4. Follow sample introduction, purging, and desorption steps described in the method.

5. If less than five samples are used for compositing, a proportionately small syringe may be used.

(e) Compositing samples prior to GC/MS analysis.
1. Inject 5-ml or equal larger amounts of each aqueous sample (up to five samples are allowed) into a 25-ml purging device using the sample introduction technique described in the method.

2. The total volume of the sample in the purging device must be 25 ml.

3. Purge and desorb as described in the method.

(7) VOC Compliance Calculations. Compliance with 310 CMR 22.07B(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) Annually or Less. Each supplier of water 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.

(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) 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.

(g) Average Exceeding VOC MCLs. When the average of four analyses made pursuant to 310 CMR 22.07B(4), 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 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.

(8) VOC Analytical Methods. Analysis for the contaminants listed in 310 CMR 22.07B(1) shall be conducted using the following EPA methods or their equivalent as approved by EPA.

Contaminant

EPA Method

Benzene

502.2, 524.2

Carbon tetrachloride

502.2, 524.2, 551.1

Chlorobenzene

502.2, 524.2

1,2-Dichlorobenzene

502.2, 524.2

1,4- Dichlorobenzene

502.2, 524.2

1,2- Dichloroethane

502.2, 524.2

cis-Dichloroethylene

502.2, 524.2

trans- Dichloroethylene

502.2, 524.2

Dichloromethane

502.2, 524.2

1,2-Dichloropropane

502.2, 524.2

Ethylbenzene

502.2, 524.2

Styrene

502.2, 524.2

Tetrachloroethylene

502.2, 524.2, 551.1

1,1,1-Trichlorobenzene

502.2, 524.2, 551.1

Trichloroethylene

502.2, 524.2, 551.1

Toluene

502.2, 524.2

1,2,4-Trichlorobenzene

502.2, 524.2

1,1-Dichloroethylene

502.2, 524.2

1,1,2-Trichloroethane

502.2, 524.2

Vinyl chloride

502.2, 524.2

Xylenes(total)

502.2, 524.2
(a) Methods 502.2 is in Methods for the Determination of Organic Compounds in Drinking Water, EPA-600/4-88-039, December 1988, Revised, July 1991.

(b) Methods 524.2, is in Methods for the Determination of Organic Compounds in Drinking Water - Supplement III, EPA/600/R-95/131, August 1995.

(c) Method 551.1 is in Methods for the Determination of Organic Compounds in Drinking Water - Supplement III, EPA/600/R-95-131, August 1995 and can be used to measure carbon tetrachloride, tetrachloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, and trichloroethylene.

(9) Maximum Contaminant Levels (MCLs) for Volatile Organic Compounds (VOC). (Reserved)

(10) Grandfathered VOC Data. The Department may allow the use of monitoring data collected after January 1, 1988, for purposes of complying with initial compliance period. If the data are generally consistent with the other requirements in 310 CMR 22.07B, the Department may use these data (i.e., a single sample rather than four quarterly samples) to satisfy the initial monitoring requirement of 310 CMR 22.07B(2)(d). Systems which use grandfathered samples and did not detect any contaminants listed in 310 CMR 22.07B(1) shall begin monitoring annually in accordance with 310 CMR 22.07B(2)(e) beginning with the initial compliance period.

(11) Increased VOC Sampling. The Department may increase required monitoring where necessary to detect variations within the system.

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

(13) 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 volatile organic chemicals under 310 CMR 22.07B, provided that the system from which the water is obtained has conducted the analyses required under 310 CMR 22.07B, unless otherwise specified by the Department.

(14) Volatile Organic BATs. The Department hereby identifies as indicated in the Table below either granular activated carbon (GAC), packed tower aeration (PTA), or both 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 22.07B(1):

BAT FOR ORGANIC CONTAMINANTS

CAS #

Chemical

GAC

PTA

71-43-2

Benzene

X

X

56-23-5

Carbon tetrachloride

X

X

95-50-1

o-Dichlorobenzene

X

X

107-06-2

1,2-Dichloroethane

X

X

156-59-2

cis-1,2-Dichloroethylene

X

X

156-60-5

trans-1,2-Dichloroethylene

X

X

75-35-4

1,1-Dichloroethylene

X

X

78-87-5

1,2-Dichloropropane

X

X

100-41-4

Ethylbenzene

X

X

108-90-7

Monochlorobenzene

X

X

106-46-7

para-Dichlorobenzene

X

X

100-42-5

Styrene

X

X

127-18-4

Tetrachloroethylene

X

X

71-55-6

1,1,1-Trichloroethane

X

X

79-01-6

Trichloroethylene

X

X

108-88-3

Toluene

X

X

75-01-4

Vinyl chloride

X

1330-20-7

Xylene

X

X

(15) New Systems/Sources. Each new supplier of water or supplier of water 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 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 22.07B.

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