40 C.F.R. § 141.25

Current through March 31, 2024
Section 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 .

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.25(a)

Contaminant MethodologyEPA methodSM 21st edition1SM 22nd edition,28 SM 23rd edition,49 SM 24th edition66 ASTM4SM online3
Naturally Occurring:
Gross alpha and betaEvaporation900.0, Rev. 1.0507110 B7110 B
Liquid Scintillation7110 DD 7283-177110 D-17.
Gross alphaCoprecipitation7110 C7110 C
Radium 226Radon emanation903.1, Rev. 1.0537500-Ra C7500-Ra CD 3454-05, -18, D 3454-21
Radiochemical903.0, Rev. 1.0547500-Ra B7500-Ra BD 2460-07
Gamma Spectrometry7500-Ra E7500-Ra E-07.
Radium 228Radiochemical904.0, Rev. 1.0627500-Ra D7500-Ra D
Gamma Spectrometry7500-Ra E7500-Ra E-07.
UraniumRadiochemical7500-U B7500-U B
ICP-MS3125D 5673-05, 10, 16
Alpha spectrometry7500-U C7500-U CD 3972-09
Laser PhosphorimetryD 5174-07
Alpha Liquid Scintillation SpectrometryD 6239-09
Man-Made:
Radioactive CesiumRadiochemical7500-Cs B7500-Cs B
Gamma Ray Spectrometry71207120D 3649-06
Radioactive IodineRadiochemical7500-I B, 7500-I C, 7500-I D7500-I B, 7500-I C, 7500-I DD 3649-06
Gamma Ray Spectrometry71207120D 4785-08, -20
Radioactive Strontium 89, 90Radiochemical7500-Sr B7500-Sr B
TritiumLiquid Scintillation7500-3H B7500-3H BD 4107-08, -20
Gamma EmittersGamma Ray Spectrometry7120, 7500-Cs B, 7500-I B7120, 7500-Cs B, 7500-I BD 3649-06, D 4785-08, -20

(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 (1.96[SIGMA] where [SIGMA] 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
limit
Gross alpha particle activity3 pCi/L.
Radium 2261 pCi/L.
Radium 2281 pCi/L.
Uranium1 [MICRO]g/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
Tritium1,000 pCi/1.
Strontium-8910 pCi/1.
Strontium-902 pCi/1.
Iodine-1311 pCi/1.
Cesium-13410 pCi/1.
Gross beta4 pCi/1.
Other radionuclides1/10 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.

40 C.F.R. §141.25

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; 89 FR 5779, Jan. 30, 2024