EDAFOLOGÍA

Volumen 8-2. Agosto 2001. pág 31-44.

LA PROBLEMÁTICA DEL SELENIO EN SUELOS CONTAMINADOS DEL ESTADO DE CALIFORNIA (E.E.U.U.)

M. Camps Arbestain

Depto. Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, 15782-Santiago de Compostela.

Abstract.The episode of selenium (Se) contamination at Kesterson Reservoir (California, U.S.A.) (1978-1986) provided a unique opportunity to study the biogeochemistry of Se. Kesterson Reservoir is a man-made marsh comprising 12 evaporative ponds that became a disposal facility for saline drainage water (total storage capacity of 5.2 x 10⁶ m³). Bioaccumulation and biomagnification of Se caused a high incidence of deformities and severe mortality in waterfowl hatchlings and resulted in the closure and drying up of the Kesterson Reservoir in 1986. The selenium in drainage waters (0.1-1.4 mg L^-1) originated in soils of the west-central San Joaquin Valley which derived from alluvial deposits of pyritic shales with high levels of Se. This contamination event led to the investigation of different alternatives in order to remediate drainage waters and soils through biological and/or chemical Se removal processes. This review discusses the latest advances related to the different Se removal techniques which are currently under study.

Key words: Selenium, Kesterson Reservoir, drainage waters, soils, remediation