This test method was developed for the purpose of measuring gross alpha radioactivity in water. It is used for the analysis of both process and environmental water to determine gross alpha activity which is often a result of natural radioactivity present in minerals.

1.1 This test method covers the measurement of alpha particle activity of water. It is applicable to nuclides that emit alpha particles with energies above 3.9 MeV and at activity levels above 0.02 Bq/mL (540 pCi/L) of radioactive homogeneous water. This test method is not applicable to samples containing alpha-emitting radionuclides that are volatile under conditions of the analysis.

1.2 This test method can be used for either absolute or relative determinations. In tracer work, the results may be expressed by comparison with a standard that is defined to be 100 %. For radioassay, data may be expressed in terms of alpha disintegration rates after calibration with a suitable standard. General information on radioactivity and measurement of radiation has been published and summarized in Practice D3648.

1.3 This 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.