ABSTRACT
The volume of literature concerning selenium (Se) in the soil environment has grown considerably over the past 50 years. Reviews [1-5] provide comprehensive surveys of this literature. In recent years, results from studies concerned with Se contamination in sediments, soils, and groundwater at Kesterson Reservoir (Merced County, California) have also become available [6-12]. In this chapter, data are presented that (a) suggest uncertainties with respect to characterization of adsorbed Se using sequential extraction methods, (b) illustrate the distribution of various Se fractions in field soil profiles, (c) demonstrate reoxidation and movement of recently reduced field soil Se inventories, and (d) show the relative mobilities of selenate (Se(VI)) and selenite (Se(IV)) under oxidizing field conditions. Data presented in the following sections come primarily from a larger set of studies conducted at Kesterson Reservoir and also in the Lahontan Valley (Churchill County, Nevada). These results are not
intended to represent "typical" soils from the western United States but rather were selected to illustrate various characteristics of Se behavior in the soil environment.
