Geochemical partitioning of actinides using sequential chemical extractions. Comparison to stable elements

We have developed a sequential extraction technique for determining the geochemical partitioning of Am, Pu, and U in soils and sediments. Stable element analyses were combined with radiometric measurements to determine the most probable geochemical host phases of these actinides in reference sediment IAEA-135. 241Am results indicate an association with carbonate minerals and organic matter. The extraction profile of 238U was similar to that of refractory elements Al, Ti, and K. 239/240Pu data suggest a fractionation of Pu into Fe-bearing phases of varying solubility. The reproducibility of the method was quite good (replicates agreed to within 10% at a 95% confidence level). (author)