Selenium (Se) contamination of agricultural soils and drainage water i
n California's San Joaquin Valley has been identified as the cause of
death and deformation in migratory waterfowl, Within the last decade,
significant research has focused on developing ways of removing Se fro
m impacted soils and waters. Microbially mediated reactions have been
identified which may have applications in this regard. These include t
ransformations of soluble, toxic Se oxyanions into less toxic volatile
or precipitated forms. This review discusses Se as an environmental c
ontaminant, with emphasis on biotransformations that largely control t
he behavior of Se in soil/water systems, The major focus is on recent
advances related to the development of useful techniques for bioremedi
ation of Se-contaminated soils and water.