Characterizing Uranium in Environmental Media Using a Combination of Radiochemistry and Metals Analysis (ICP/MS) Methods

H.T. Downey (MACTEC)

There are several analytical methods available for the analysis of uranium in environmental media. As part of the first round of characterization at an Environmental Protection Agency (EPA) Superfund site, uranium was analyzed using a combination of radiochemistry and metals analysis (ICP/MS). This Site encompasses approximately 46 acres and includes a wide variety of environmental media to be characterized. Samples were collected from surface soil, subsurface soil, ground water, surface water, sediment, and bog peat. The approach to sample analysis for uranium was primarily with ICP/MS which reported U-235, U-238, and total uranium concentrations, with at least 20% of the sample locations also being analyzed by radiochemistry (alpha spectroscopy) which reported U-234, U-235, and U-238 concentrations. This approach was selected since the ICP/MS analysis could be performed with less sample volume, faster results, lower detection sensitivity, and lower cost than alpha spectroscopy. A comparison of the ICP/MS and alpha spectroscopy techniques and measurement sensitivity is presented along with an evaluation of the data including uranium enrichment. In addition, the differences in sample volume and costs are estimated by using this approach as compared to only using alpha spectroscopy for analysis of uranium. The results of this evaluation provide input for determining future methods of analysis for uranium in environmental media.

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