The birds of Kesterson Reservoir: a historical perspective.

Beginning in the late 1970s, Kesterson Reservoir was used for disposal of subsurface drainage from agricultural fields in California's San Joaquin Valley. During 1983-1985, studies were conducted to evaluate the effects of chemicals in this agricultural drainwater on aquatic birds using Kesterson Reservoir. These studies included analyses of food-chain biota (such as plants, aquatic invertebrates, and fish) and bird tissues or eggs, as well as measuring adverse effects on health and reproduction of the birds. Results of the integrated set of field and experimental studies showed that selenium was the only chemical found at concentrations high enough to cause the adverse effects on bird health or reproduction that were observed. This article provides a summary of the field studies conducted at Kesterson Reservoir (and some of the related field and experimental studies conducted elsewhere) to evaluate the effects of irrigation drainage water contaminants on aquatic birds.