GEOCHEMICAL PARTITIONING OF ACTINIDES USING SEQUENTIAL CHEMICAL EXTRACTIONS - COMPARISON TO STABLE ELEMENTS

We have developed a sequential extraction technique for determining th e geochemical partitioning of Am, Pu, and U in soils and sediments. St able element analyses were combined with radiometric measurements to d etermine the most probable geochemical host phases of these actinides in reference sediment IAEA-135. Am-241 results indicate an association with carbonate minerals and organic matter. The extraction profile of U-238 was similar to that of refractory elements Al, Ti, and K. Pu-23 9/240 data suggest a fractionation of Pu into Fe-bearing phases of var ying solubility. The reproducibility of the method was quite good (rep licates agreed to within 10% at a 95% confidence level).