Inferences About Radionuclide Mobility in Soils Based on the Solid/Liquid Partition Coefficients and Soil Properties

Abstract To assist transport modeling in assessments of the radiological impact of a geological repository for radioactive wastes, the mobility of various elements was studied in arable and wetland soils in the Forsmark region, Sweden. Pore water and total element contents were determined for five types of unconsolidated deposits (reg-olith), spanning a wide range of soil properties with respect to pH and organic matter content. Two soil depths were sampled to capture element mobility in regolith layers affected and unaffected by soil-forming processes. The solid/liquid partition coefficients (Kd values) for most ele-ments varied significantly among regolith types. For most elements, the observed variations in Kd values could be explained by variations in soil properties. For many ele-ments, mobility increased with decreasing soil pH. The results provide a significant addition of data on radionu-clide retention in soils, taking account of soil properties and processes