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Title 40

Displaying title 40, up to date as of 9/16/2021. Title 40 was last amended 9/14/2021.

Title 40

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§ 141.25 Analytical methods for radioactivity.

(a) Analysis for the following contaminants shall be conducted to determine compliance with § 141.66 (radioactivity) in accordance with the methods in the following table, or the alternative methods listed in appendix A to subpart C this part, or their equivalent determined by EPA in accordance with § 141.27.

Contaminant Methodology Reference (Method of Page Number)
Naturally Occurring:
Gross alpha11 and beta Evaporation 900.0 p. 1 00-01 p. 1 302, 7110 B, 7110 B-00 R-1120-76
Gross alpha11 Coprecipitation 00-02 7110 C, 7110 C-00
Radium 226 Radon emanation 903.1 p. 16 Ra-04 p. 19 305, 7500-Ra C, 7500-Ra C-01 D3454-97 R-1141-76 Ra-04 NY9,
Radiochemical 903.0 p. 13 Ra-03 304, 7500-Ra B, 7500-Ra B-01 D2460-97 R-1140-76 GA14
Radium 228 Radiochemical 904.0 p. 24 Ra-05 p. 19 7500-Ra D, 7500-Ra D-01 R-1142-76 NY9,
Uranium12 Radiochemical 908.0 7500-U B, 7500-U B-00
Fluorometric 908.1 7500-U C (17th Ed.) D2907-97 R-1180-76, R-1181-76 U-04
ICP-MS 200.813 3125 D5673-03
Alpha Spectrometry 00-07 p. 33 7500-U C (18th, 19th, or 20th Ed.), 7500-U C-00 D3972-97, 02 R-1182-76 U-02
Laser Phosphorimetry D5174-97, 02
Radioactive Cesium Radiochemical 901.0 p. 4 7500-Cs B, 7500-Cs B-00 D2459-72 R-1111-76
Gamma Ray Spectrometry 901.1 p. 92 7120, 7120-97 D3649-91, 98a R-1110-76
Radioactive Iodine Radiochemical 902.0 p. 6 7500-I B, 7500-I B-00
p. 9 7500-I C, 7500-I C-00
7500-I D, 7500-I D-00 D3649-91, 98a
Gamma Ray Spectrometry 901.1 p. 92 7120, 7120-97 D4785-93, 00a
Radioactive Strontium 89, 90 Radiochemical 905.0 p. 29 Sr-04 p. 65 303, 7500-Sr B, 7500-Sr B-01 R-1160-76 Sr-01, Sr-02
Tritium Liquid Scintillation 906.0 p. 34 H-02 p. 87 306, 7500-3 H B, 7500-3 H B-00 D4107-91, 98 (Reapproved 2002) R-1171-76
Gamma Emitters Gamma Ray Spectrometry 901.1 p. 92 7120, 7120-97 D3649-91, 98a R-1110-76 Ga-01-R
902.0 7500-Cs B, 7500-Cs B-00 D4785-93, 00a
901.0 7500-I B, 7500-I B-00

(b) When the identification and measurement of radionuclides other than those listed in paragraph (a) of this section is required, the following references are to be used, except in cases where alternative methods have been approved in accordance with § 141.27.

(1) Procedures for Radiochemical Analysis of Nuclear Reactor Aqueous Solutions, H. L. Krieger and S. Gold, EPA-R4-73-014. USEPA, Cincinnati, Ohio, May 1973.

(2) HASL Procedure Manual, Edited by John H. Harley. HASL 300, ERDA Health and Safety Laboratory, New York, NY., 1973.

(c) For the purpose of monitoring radioactivity concentrations in drinking water, the required sensitivity of the radioanalysis is defined in terms of a detection limit. The detection limit shall be that concentration which can be counted with a precision of plus or minus 100 percent at the 95 percent confidence level (1.96σ where σ is the standard deviation of the net counting rate of the sample).

(1) To determine compliance with § 141.66(b), (c), and (e) the detection limit shall not exceed the concentrations in Table B to this paragraph.

Table B - Detection Limits for Gross Alpha Particle Activity, Radium 226, Radium 228, and Uranium

Contaminant Detection
Gross alpha particle activity 3 pCi/L.
Radium 226 1 pCi/L.
Radium 228 1 pCi/L.
Uranium 1 µg/L

(2) To determine compliance with § 141.66(d) the detection limits shall not exceed the concentrations listed in Table C to this paragraph.

Table C - Detection Limits for Man-made Beta Particle and Photon Emitters

Radionuclide Detection limit
Tritium 1,000 pCi/1.
Strontium-89 10 pCi/1.
Strontium-90 2 pCi/1.
Iodine-131 1 pCi/1.
Cesium-134 10 pCi/1.
Gross beta 4 pCi/1.
Other radionuclides 1/10 of the applicable limit.

(d) To judge compliance with the maximum contaminant levels listed in § 141.66, 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.

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

[41 FR 28404, July 9, 1976, as amended at 45 FR 57345, Aug. 27, 1980; 62 FR 10173, Mar. 5, 1997; 65 FR 76745, Dec. 7, 2000; 67 FR 65250, Oct. 23, 2002; 69 FR 38855, June 29, 2004; 69 FR 52180, Aug. 25, 2004; 72 FR 11245, Mar. 12, 2007; 74 FR 30958, June 29, 2009]