Adsorption of plutonium on shallow sediments at the Hanford Site

Models of plutonium transport in groundwater require the evaluation of parameters that describe adsorption of plutonium on shallow sediments under the Hanford Site. Adsorption of plutonium species having different initial oxidation states [(IV), (V), and (VI)] was measured as a function of time and plutonium concentration in a typical groundwater. The results indicate that plutonium (VI) is not adsorbed significantly because of carbonate complexing. Both plutonium (VI) and (V) are reduced slowly to plutonium (IV) by reducing components in the sediments, and the plutonium (IV) subsequently is strongly absorbed. The adsorption reaction is mostly reversible. Distribution coefficients range from 5000 to 30,000 mL/g