Maximum Radionuclide Contaminant Levels, Monitoring Requirements and Analytical

Methods Effective as of December 8, 2003 (1) Maximum Contaminant Levels for Radionuclides: The maximum contaminant levels for radionuclide contaminants of 310 CMR 22.09A apply only to community water systems. The MCLs for radionuclides are as indicated in 310 CMR 22.09A: Table A: TABLE A MAXIMUM CONTAMINANT LEVELS FOR RADIONUCLIDES Contaminant MCL Combined radium-226 and radium-228 5 pCi/L Gross alpha particle activity (excluding radon and uranium) 15 pCi/L Beta particle and photon radioactivity 4 mrem/year Uranium 30 µg/L (a) MCL for Combined Radium-226 And radium-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. (b) 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. (c) 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 four millirem/year (mrem/year). 2. Except for the radionuclides listed in 310 CMR 22.09A: Table B, the concentration of man-made radionuclides causing four mrem total body or organ dose equivalents must be calculated on the basis of two 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. 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 Office of the Federal Register, 800 North Capitol Street, NW., Suite 700, Washington, DC. 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 four mrem/year. 22.09A: continued 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: The regeneration solution contains high concentrations of the contaminant ions. Disposal options should a be carefully considered before choosing this technology. When POU devices are used for compliance, programs for long-term operation, maintenance, and b monitoring must be provided by water utility to ensure proper performance. Reject water disposal options should be carefully considered before choosing this technology. See other c RO limitations described in the SWTR Compliance Technologies Table. The combination of variable source water quality and the complexity of the water chemistry involved d may make this technology too complex for small surface water systems. Removal efficiencies can vary depending on water quality. e This technology may be very limited in application to small systems. Since the process requires static f 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. This technology is most applicable to small systems that already have filtration in place. g Handling of chemicals required during regeneration and pH adjustment may be too difficult for small h systems without an adequately trained operator. Assumes modification to a coagulation/filtration process already in place. i TABLE E COMPLIANCE TECHNOLOGIES BY SYSTEM SIZE CATEGORY FOR RADIONUCLIDES Contaminant Compliance technologies for system size categories (population served) 3,300–10,000 25–500 501–3,300 3300-10,000 1. Combined radium-226 and radium-228 1, 2, 3, 4, 5, 6, 7, 8, 9 1, 2, 3, 4, 5, 6, 7, 8, 9 1, 2, 3, 4, 5, 6, 7. 8, 9 2. Gross alpha particle activity 3, 4 3, 4 3, 4 3. Beta particle activity and photon activity 1, 2, 3, 4 1, 2, 3, 4 1, 2, 3, 4 4. Uranium 1, 2, 4, 10, 11 1, 2, 3, 4, 5, 10, 11 1, 2, 3, 4, 5, 10, 11 Note: Numbers correspond to those technologies found listed in 310 CMR 22.09A(1): Table D. (2) Monitoring Frequency and Compliance Requirements for Radionuclides in Community Water Supplies. (a) Monitoring Frequency and Compliance Requirements for Gross Alpha Particle Activity, Radium-226, Radium-228, and Uranium. 1. Community water systems must conduct initial monitoring to determine compliance with the maximum contaminant levels listed in 310 CMR 22.09A 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 310 CMR 22.09A(5)(b). a. Applicability and sampling location for existing community water systems or sources. All existing community water systems using ground water, surface water or systems using both ground and surface water (for the purpose of 310 CMR 22.09A referred to as systems) must sample at every entry point to the distribution system that is representative of all sources being used (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 Department has designated a distribution system location, in accordance with 310 CMR 22.09A(2)(b)2. 22.09A: continued b. Applicability and sampling location for new community water systems or sources. All new community water systems or community water systems 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. Community water systems must conduct more frequent monitoring when ordered by the Department 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. (b) Initial Monitoring. The supplier of water must conduct initial monitoring for gross alpha particle activity, radium-226, radium-228, and uranium as follows: 1. Systems without acceptable historical data, as defined in 310 CMR 22.09A(2)(b)1. through 4., must collect four consecutive quarterly samples at all sampling points before December 31, 2007. 2. Grandfathering of Data. The Department 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 Department 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 Department must make a written finding indicating how the data conforms to these requirements. 3. For gross alpha particle activity, uranium, radium-226, and radium-228 monitoring, the Department 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. 4. If the average of the initial monitoring results for a sampling point is above the MCL, the supplier of water 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 Department. (c) Reduced Monitoring. The Department 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. 1. 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 310 CMR 22.09A: Table G, the supplier of water must collect and analyze for that contaminant using at least one sample at that sampling point every nine years. 2. 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 ½ the MCL, the supplier of water 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 ½ the MCL, the supplier of water must collect and analyze for that contaminant using at least one sample at that sampling point every six years. 22.09A: continued 3. For gross alpha particle activity and uranium, if the average of the initial monitoring results for each contaminant is above ½ the MCL but at or below the MCL, the supplier of water 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 ½ the MCL but at or below the MCL, the supplier of water must collect and analyze at least one sample at that sampling point every three years. 4. The supplier of water 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 ½ the MCL, then the next monitoring period for that sampling point is three years). 5. If a supplier of water 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 supplier of water enters into another schedule as part of a formal compliance agreement with the Department. (d) Compositing. To fulfill quarterly monitoring requirements for gross alpha particle activity, radium-226, radium-228, or uranium, a supplier of water may composite up to four consecutive quarterly samples from a single entry point if analysis is done within a year of the first sample. The Department will treat analytical results from the composited sample 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 ½ MCL, the Department may direct the supplier of water to take additional quarterly samples before allowing the supplier of water to sample under a reduced monitoring schedule. (e) 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% (1.65F, where F is the standard deviation of the net counting rate of the sample) for radium- 226 and uranium. When a supplier of water 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, ½ the detection limit will be used to determine compliance and the future monitoring frequency. (3) Monitoring and Compliance Requirements for Beta Particle and Photon Radioactivity. To determine compliance with the maximum contaminant levels in 310 CMR 22.09A: Table A for beta particle and photon radioactivity, a system must monitor at a frequency as follows: (a) Community water systems (both surface and ground water) designated by the Department as vulnerable must sample for beta particle and photon radioactivity. The supplier of water 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 Department. Systems already designated by the Department must continue to sample until the Department reviews and either reaffirms or removes the designation. 1. 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 Department may reduce the frequency of monitoring at that sampling point to once every three years. The supplier of water must collect all samples required in 310 CMR 22.09A(3)(a) during the reduced monitoring period. 2. For systems in the vicinity of a nuclear facility, the Department may allow the community water system to utilize environmental surveillance data collected by the nuclear facility in lieu of monitoring at the system’s entry point(s), where the Department 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 310 CMR 22.09A(3)(a). 22.09A: continued (b) Community water systems (both surface and ground water) designated by the Department as utilizing waters contaminated by effluents from nuclear facilities must sample for beta particle and photon radioactivity. The supplier of water 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 Department. Systems already designated by the Department as systems using waters contaminated by effluents from nuclear facilities must continue to sample until the Department reviews and either reaffirms or removes the designation. 1. 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. 2. For iodine-131, a composite of five consecutive daily samples shall be analyzed once each quarter. As ordered by the Department, more frequent monitoring shall be conducted when iodine-131 is identified in the finished water. 3. 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. 4. If the gross beta particle activity beta 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 Department may reduce the frequency of monitoring at that sampling point to every three years. The supplier of water must collect all samples required in 310 CMR 2.09A(3)(b) during the reduced monitoring period. 5. For systems in the vicinity of a nuclear facility, the Department may allow the community water system to utilize environmental surveillance data collected by the nuclear facility in lieu of monitoring at the system’s entry point(s), where the Department 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 310 CMR 22.09A(3)(b). (c) Community water systems designated by the Department to monitor for beta particle and photon radioactivity can not apply to the Department for a waiver from the monitoring frequencies specified in 310 CMR 22.09A(3)(a) or (b). (d) 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. The supplier of water is 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. (e) 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 310 CMR 22.09A(1)(c)1., using the formula in 310 CMR 22.09A(1)(c)2. Doses must also be calculated and combined for measured levels of tritium and strontium to determine compliance. (f) The supplier of water must monitor monthly at the sampling point(s) which exceed the maximum contaminant level in 310 CMR 22.09A: Table A beginning the month after the exceedance occurs. The supplier of water must continue monthly monitoring until the system has established, by a rolling average of three 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 310 CMR 22.09A(3)(a)2. or (b)1. (4) General Monitoring and Compliance Requirements for Radionuclides. (a) The Department may require more frequent monitoring than specified in 310 CMR 22.09A(2) and (3), or may require confirmation samples at its discretion. The results of the initial and confirmation samples will be averaged for use in compliance determinations. 22.09A: continued (b) Each supplier of water shall monitor at the time designated by the Department during each compliance period. (c) Compliance with 310 CMR 22.09A(1)(a) through (d) 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. 1. 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. 2. 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. 3. Each supplier of water must include all samples taken and analyzed under the provisions of 310 CMR 22.09A in determining compliance, even if that number is greater than the minimum required. 4. If a supplier of water 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. 5. 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, ½ the detection limit will be used to calculate the annual average. (d) The Department has the discretion to delete results of obvious sampling or analytic errors. (e) If the MCL for radioactivity set forth in 310 CMR 22.09A(1)(a) through (d) is exceeded, the operator of a community water system must give notice to the Department pursuant to 310 CMR 22.15 and shall notify the public as required by 310 CMR 22.16. (5) Analytical Methods for Radioactivity. (a) Analysis for the following contaminants shall be conducted to determine compliance with 310 CMR 22.09A(1) in accordance with the methods in 310 CMR 22.09A: Table F or their equivalent as determined by USEPA. 22.09A: continued TABLE F ANALYTICAL METHODS FOR RADIONUCLIDE MONITORING Contaminant Methodology Reference (method or page number) EPA EPA EPA EPA SM ASTM USGS DOE Other Naturally Occurring: Gross alpha & beta Evaporation p 1 p 1 302, 7110 B 7110 B-00 R–1120–76 Gross alpha Co-precipitation 7110 C 7110 C-00 Radium 226 Radon emination p 16 Ra-04 p 19 305, 7500-Ra C D 3454–97 R–1141–76 Ra-04 N.Y. 9 Radiochemical p 13 Ra-03 7500 Ra C-01 304, 7500-Ra B 7500-Ra B-01 D 2460–97 R–1140–76 GA14 Radium 228 Radiochemical p 24 Ra-05 p 19 7500-Ra D 7500-RaD-01 R–1142–76 N.Y. 9 N.J. 10 Uranium Radiochemical 7500-U B 7500-U B-00 GA14 Fluorometric 7500-U C (17 Ed.) D 2907–97 R–1180–76 U-04 th R–1181–76 Alpha spectronomy p 33 7500-U C (18 , 19 , th th or 20 edition) 7500- th U C-00 D 3972–97, 02 R–1182–76 U-02 Laser phosphorimetry D 5174–97, 02 ICP-MS D 5673-03 Man-made: Radioactive cesium Radiochemical p 4 7500-Cs B 7500-Cs B-00 D 2459–72 R–1111–76 Gamma ray spectrometry p 92 7120, 7120-97 D 3649–91, 98a R–1110–76 4.5.2.3 Radioactive iodine Radiochemical p 6 7500–1 B 7500-1 B-00 p 9 7500–1 C 7500-1C-00 D 3649–91, 98a 7500–1 D 7500-1 D-00 Gamma ray spectrometry p 92 7120, 7120-97 D 4785–93, 00a 4.5.2.3 Radioactive Strontium 89, 90 Radiochemical p 29 Sr-04 p 65 303, 7500- Sr B, 7500-Sr B-01 R–1160–76 Sr-01 Sr-02 Tritium Liquid scintillation p 34 H-02 p 87 306,7500–3H B, 7500- H B-00 D 4107–91, 98 (Reapproved 2002) R–1171–76 Gamma emitters Gamma ray Spectrometry p 92 7120, 7120-97 D 3649–91, 98a R–1110–76 Ga-01-R 7500-Cs B 7500-Cs B-00 D 4785–88 93, 00a 7500-I B, 7500-I B-00 Prescribed Procedures for Measurement of Radioactivity in Drinking Water, EPA 600/4–80–032 , August 1980. Available at U.S. Department of Commerce, National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 (Telephone 800–553–6847), PB 80–224744, except Method 200.8, “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 1”, EPA 600-R-94-111, May 1994. Available at NTIS, PB95- 125472. 22.09A: continued Interim Radiochemical Methodology for Drinking Water, EPA 600/4–75–008 (revised), March 1976. Available at NTIS, ibid. PB 253258. Radiochemistry Procedures Manual, EPA 520/5–84–006, December 1987. Available at NTIS, ibid. PB 84–215581. Radiochemical Analytical Procedures for Analysis of Environmental Samples, U.S. Department of Energy, March 1979. Available at NTIS, ibid. EMSL LV 053917. Standard Methods for the Examination of Water and Wastewater, 13 , 17 , 18 , 19 , or 20 editions, th th th th th 1971, 1989, 1992, 1995 and 1998. Available at American Public Health Association, 1015 Fifteenth Street N.W., Washington, D.C. 20005. Methods 302, 303, 304, 305 and 306 are only in the 13 edition. th 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, 7500–3H B are in the 17 , 18 , 19 , and 20 editions. Method 7110C is in the 18 , 19 , th th th th th th and 20 editions. Method 7500-U C Fluorometric Uranium is only in the 17 Edition, and 7500-U C th th Alpha spectrom-etry is only in the 18 , 19 , and 20 editions. Method 7120 is only in the 19 and 20 th th th th th editions. Methods 302, 303, 304, 305 and 306 are only in the 13 edition. Method 3125 is only in the th 20 edition. Methods 7110 B-00, 7110 C-00, 7500-Ra B-01, 7500-Ra C-01, 7500 Ra D-01, 7500-U B- th 00, 7500-U C-00, 7500-1 B-00, 7500-1 C-00, 7500-1 D-00, 7120-97, 7500-Sr B-01, and 7500- H 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. Annual Book of ASTM Standards, Vol. 11.01 and 11.02, 1999, 2002; American Society for Testing and Materials 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 the American Society for Testing and Materials, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959. 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 Geo-logical Survey, 1977. Available at U.S. Geological Survey Information Services, Box 25286, Federal Center, Denver, CO 80225–0425. EML Procedures Manual, 27 (1990), or 28 (1997) Editions, Volume 1 and 2; either edition may be th th used. In the 27 Edition Method Ra-04 is listed as Ra-05 and Method Ga-01-R is listed as Sect. 4.5.2.3. th Available at the Environmental Measurements Laboratory, U.S. Department of Energy (DOE), 376 Hudson Street, New York, NY 10014–3621. Determination of Ra-226 and Ra-228 (Ra-02), January 1980; Revised June 1982. Available at Radiological Sciences Institute Center for Laboratories and Research, New York State Department of Health, Empire State Plaza, Albany, NY 12201. 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. Natural uranium and thorium-230 are approved as gross alpha-particle activity calibration standards for the gross alpha co-precipitation and evaporation methods; americium-241 is approved for use with the gross alpha co-precipitation methods. If uranium (U) is determined by mass-type methods ( i.e., fluorometric or laser phosphorimetry), a 0.67 pCi/mg uranium conversion factor must be used. This conversion factor is conservative and is based on the 1:1 activity ratio of U-234 to U-238 that is characteristic of naturally-occurring uranium in rock. 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 1, EPA 600-R-94-111, May 1994. Available at NTIS, PB 95- 125472. 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) To determine compliance with 310 CMR 22.09A(1) the detection limit shall not exceed the concentrations as indicated in 310 CMR 22.09A Table G. 22.09A: continued TABLE G REQUIRED REGULATORY DETECTION LIMITS FOR VARIOUS RADIOCHEMICAL CONTAMINANTS Contaminant Detection Limit (pCi/L) Gross alpha Gross beta Radium-226 Radium-228 Uranium [ug/L] Cesium-134 Strontium-89 Strontium-90 Iodine-131 Tritium Other radionuclides and Photon/Gamma Emmitters 1/10 of the rule th (c) To judge compliance with the maximum contaminant levels listed in 310 CMR 22.09A(1), 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.