ABSTRACT
This chapter focuses on the geochemistry of Se in groundwater systems and processes affecting transport and retardation. The geochemistry of such systems is subject to wide variations in redox states and therefore aqueous speciation and microbial processes. The chapter evaluates the effects of these variables on Se transport in different
geochemical environments. Two case studies, one in the agricultural source area in the San Joaquin Valley and the other in the engineered discharge area at Kesterson Reservoir, illustrate the interdependency of many of these redox processes and their controls on Se movement in groundwater.
