Environmental chemistry of selenium

Abstract

The drainage of agricultural wastewater from the rich San Joaquin Valey — a problem that has vexed farmers, scientists, and politicians for many years — reached a climax early this year, when a halt was ordered in the delivery of federal irigation water to 42,0 acres of land in the Westlands area of the Valey. Behind this action was the detection of high levels of selenium in Kesterson Reservoir, terminus for the 80-mile-long San Luis Drain, which caries saline wastewater from the Westlands Irigation District to Kesterson. Built in 1971, the 12 shalow evaporation ponds at Kesteron suported a variety of fish and wildlife. Mortalities and deformities atributed to acumulated selenium atracted national atention. In this article, Dr. Richard Burau, Profesor of Soil Chemistry in the Department of Land, Air, and Water at UC Davis, reviews what is known about selenium and how it enters the fod chain.