Standard Test Method for Analysis of Total and Isotopic Uranium and Total Thorium in Soils by Inductively Coupled Plasma-Mass Spectrometry
This test method measures the presence of uranium and thorium in soil that occurs naturally and as a result of contamination from nuclear operations and uranium ore processing. The reporting detection levels (RDLs) of total uranium and thorium are well below the normal background in soil. The normal background level for uranium is between 3 and 5 µg/g in most geographic areas and slightly higher for thorium. The 235U enrichment is also measured from an initial sample pass through the instrument. The other less abundant uranium isotopes (234U and 236U) are measured down to a typical soil background level after sample concentration and a second sample analysis. This allows for calculation of individual isotopic uranium and total uranium activity.
