Geochemical Factors Affecting the Behavior of Antimony, Cobalt, Europium, Technetium, and Uranium in Vadose Sediments

In developing the Field Investigation Report for the Waste Management Area S-SX at the Hanford Site, Cs was the only gamma emitting radionuclide of concern (Knepp 2002). However, in WMA B-BX-BY, the spectral gamma logging data identify seven gamma emitting radionuclides, Cs, Sb, Eu, Eu, Co, U, and U (DOE-GJPO 1998). The geochemical behaviors of several of these radionuclides, Sb and the two europium isotopes, have not been extensively investigated at the Hanford Site. This task was initiated to assure that our understanding of the geochemical properties affecting the environmental behavior of these radionuclides reflects the current state of knowledge. A literature review was conducted to assess the important oxidation/reduction, aqueous speciation, solubility, and adsorption processes affecting the environmental behavior of antimony, cobalt, europium, technetium, and uranium in vadose zone sediments with low-organic matter content in semi-arid environments such as those at the Hanford Site. Technetium-99 was included in this task because of its importance in the long-term risk calculations. This report presents the results of this literature review. a Knepp AJ. 2002. Field Investigation Report for Waste Management Area S-SX. RPP-7884, Rev. 0, CH2M HILL Hanford Group, Inc., Richland, Washington. b DOE-GJPO (U.S. Department of Energy, Grand Junction Project Office). 1998. Vadose Zone Characterization Project at the Hanford Tank Farms: BX Tank Farm Report. GJO-HAN-19, U.S. Department of Energy, Grand Junction Project Office, Grand Junction, Colorado.