ASTM D 7939 : 2015

1.1This test method is specifically for Americium-241 (²⁴¹Am) in drinking water and other aqueous samples. However, if any isotopes of curium are present in the sample, they will be carried with americium during the analytical separation process and will be observed in the final alpha spectrum. The presence of ²⁴³Am in the water sample will bias the results obtained by this test method.

1.2This test method is applicable to samples in which radioactive contamination is from either known or unknown origins. If any filtration of the sample is performed before starting the analysis, those solids should be analyzed separately. The results from the analysis of these solids should be reported separately (as a suspended activity concentration for the water volume filtered) but identified with the filtrate results.

1.3This test method is applicable to the determination of soluble ²⁴¹Am. This test method is not applicable to the determination of ²⁴¹Am in highly insoluble particulate matter possibly present in water samples contaminated as a result of a radiological dispersal device (RDD) event.

1.4This test method uses rapid radiochemical separation techniques for determining americium in water samples following a radiological or nuclear incident. Although, with this test method, concentrations of ²⁴¹Am on the same order of magnitude as methods used for the Safe Drinking Water Act (SDWA) can be detected, this test method is not a substitute for SDWA-approved methods for ²⁴¹Am.

1.5Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.

1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.