§ 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. Radionuclide Critical organ pCi per liter
2. Tritium Total body 20,000
3. Strontium-90 Bone Marrow 8

(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-228 Ion exchange, reverse osmosis, lime softening.
2. Uranium Ion exchange, reverse osmosis, lime softening, coagulation/filtration.
3. Gross alpha particle activity (excluding Radon and Uranium) Reverse osmosis.
4. Beta particle and photon radioactivity Ion 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 required1 Raw water quality range and
1. Ion exchange (IE) (a) Intermediate All ground waters.
2. Point of use (POU2) IE (b) Basic All ground waters.
3. Reverse osmosis (RO) (c) Advanced Surface waters usually require pre-filtration.
4. POU2 RO (b) Basic Surface waters usually require pre-filtration.
5. Lime softening (d) Advanced All waters.
6. Green sand filtration (e) Basic.
7. Co-precipitation with Barium sulfate (f) Intermediate to Advanced Ground waters with suitable water quality.
8. Electrodialysis/electrodialysis reversal Basic to Intermediate All ground waters.
9. Pre-formed hydrous Manganese oxide filtration (g) Intermediate All ground waters.
10. Activated alumina (a), (h) Advanced All ground waters; competing anion concentrations may affect regeneration frequency.
11. Enhanced coagulation/filtration (i) Advanced Can treat a wide range of water qualities.

Table D - Compliance Technologies by System Size Category for Radionuclide NPDWR's

Contaminant Compliance technologies1 for system size categories (population served) 3,300-10,000
25-500 501-3,300
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.

[65 FR 76748, Dec. 7, 2000]