Sorption Behavior of Uranium in Soils

To estimate the behavior of U in agricultural environments, it is necessary to identify and quantify the factors mainly ruling the sorption behavior of U in soils. Although several studies have investigated liquid/solid distributions of U in soils, available information are often based on small sample sizes and the distribution coefficients are either generated by only one U concentration stage (Echevarria et al. 2001) or possible influencing factors (e.g. pH-value, fulvic acids) are investigated separately without considering possible co-effects (Echevarria et al. 2001, Kornilivich et al. 2001). Several studies have reported of increasing U solubility with increasing carbonate content, due to the formation of negatively charged U-carbonate-complexes with a lower affinity to sorption active soil components (Echevarria et al. 2001, Yamaguchi et al. 2009). Echevarria et al. (2001) and Vandenhove et al. (2007) characterized the pH value as the predominant influencing factor, determining U K D values in soils. Both reported of decreasing K D values with increasing pH values. Echevarria et al. (2001) observed a strong dependence to the presence or absence of carbonates, meanwhile Vandenhove et al. (2007) found further influences of organic carbon and amorphous iron oxide contents.
Following up, the present study aims to quantify the concentration dependant sorption partition coefficients for agricultural soils by batch experiment with increasing concentrations of U and a high number of different soil-types, varying in those physico-chemical properties, which are hypothesized to influence the sorption behavior of U.