This test method is specifically for the alpha emitting thorium isotopes (228Th, 230Th and 232Th) in drinking water and other aqueous samples. Thorium is less likely to be found in neutral or alkaline waters, but may be more prevalent in acidic waters such effluent from mines (U.S. NRC Regulatory Guides 4.14 and 4.15). This 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 as needed. 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. This test method is applicable to the determination of soluble 228Th, 230Th and 232Th. This test method is not applicable to the determination of 228Th, 230Th and 232Th in highly insoluble particulate matter possibly present in water samples contaminated as a result of a radiological dispersion device (RDD) event.
KeywordsThorium-228, thorium-229, thorium-230, thorium-232, extraction chromatography; alpha spectrometry; radioactivity; radiochemistry.
Needed by environmental laboratories analyzing water samples collected in the vicinity of facilities that may enhance naturally occurring radioactive materials levels through industrial processes.
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
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