Selenium Levels in Biota from Irrigation Drainwater Impoundments in the San Joaquin Valley, California

ABSTRACT Waterfowl, fish, invertebrates, and plants were collected from impoundments used for evaporating subsurface irrigation drainwater in Kings and Kern counties, California. Specimens were analyzed for trace elements with emphasis on selenium. Dry weight concentrations of total selenium ranged from 2.5 to 17 μg/g in wigeongrass, Ruppia maritima; 7.6 to 30 μg/g in water boatmen, Corixidae; 12 to 40 μ/g in mosquitofish, Gambusia affinis; 86 to 100 μg/g in eared grebe, Podiceps niqricollis, livers; 14 to 120 μg/g in ruddy duck, Oxyura jamaicensis, livers; and 6.8 to 48 μg/g in northern shoveler, Anas clypeata, livers. Concentrations of dissolved selenium ranged from less than 1 to 37 μg/L during a 12-month period for inflows to the drainwater evaporation ponds.