---
kind: "section"
citation: "40 C.F.R. § 141.25"
title: "40"
number: "141.25"
heading: "Analytical methods for radioactivity."
url: "https://uscodex.org/cfr/40/141.25"
---

# §141.25. Analytical methods for radioactivity.

- (a) Analysis for the following contaminants shall be conducted to determine compliance with [§ 141.66](/cfr/40/141.66.md) (radioactivity) in accordance with the methods in the following table, or the alternative methods listed in appendix A to [subpart C](/cfr/40/subpartC.md) this part, or their equivalent determined by EPA in accordance with [§ 141.27](/cfr/40/141.27.md).
- (b) When the identification and measurement of radionuclides other than those listed in [paragraph (a)](#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](/cfr/40/141.27.md).
  - (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)](/cfr/40/141.66.md?p=b), [(c)](/cfr/40/141.66.md?p=c), and [(e)](/cfr/40/141.66.md?p=e) the detection limit shall not exceed the concentrations in Table B to this paragraph.
  - (2) To determine compliance with [§ 141.66(d)](/cfr/40/141.66.md?p=d) the detection limits shall not exceed the concentrations listed in Table C to this paragraph.
- (d) To judge compliance with the maximum contaminant levels listed in [§ 141.66](/cfr/40/141.66.md), 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.

## Notes

### Amendments

[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]

### Authority

Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j-9, and 300j-11.

### Source

Source: 40 FR 59570, Dec. 24, 1975, unless otherwise noted.

### Amendments

[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]