Kesterson Reservoir: 30 Years of Selenium Risk Assessment and Management.

Severe effects of selenium (Se) occurred among birds feeding and nesting at Kesterson Reservoir (San Joaquin Valley, California, USA) in 1983 to 1985. This paper describes the integration of site monitoring, risk assessment, and management actions conducted after the effects of Se were discovered. Selenium contamination of the site occurred over just a few years, but actions to resolve the contamination issues required >20 y.

Fish whole-body selenium: interspecies translation experiment.

The Total Maximum Daily Load (TMDL) for selenium in the freshwater drainages to Newport Bay, California, is being developed based on selenium concentration in the tissues of fish and bird eggs. This paper demonstrates the use of fish mesocosms and monitoring results to facilitate the comparisons of selenium contamination across fish species and areas of the watershed with differing fish assemblages. In this watershed, mosquitofish dominate across all the small, upper watershed drainages while sunfish family species dominate in deeper, ponded reaches of the lower watershed.

Contaminants in sediment, food-chain biota, and bird eggs from the Newport Bay watershed, Orange County, California.

Groundwater-related discharges in the San Diego Creek/Newport Bay watershed in Orange County, California have the potential to adversely affect the surface waters within the watershed and would likely not comply with the established total maximum daily loads (TMDLs) for the watershed. In 2004 and 2005, we studied the concentrations of contaminants of TMDL concern (particularly selenium [Se]) in birds that are at risk of exposure to contaminated food items because they feed and nest in the Newport Bay watershed. Most bioaccumulation is from elevated Se in groundwater downstream of a historic terminal swamp.

Conducting site-specific assessments of selenium bioaccumulation in aquatic systems.

Selenium (Se) is a chemical of concern at many locations across North America and elsewhere, and site-specific conditions are important when evaluating its bioaccumulation and effects in aquatic ecosystems. Most regulatory criteria and guidelines are based on waterborne Se concentrations. In contrast, the draft water quality chronic criterion of the US Environmental Protection Agency (USEPA) is based on Se concentrations in whole-body fish, and current information suggests the agency will issue a new draft criterion based in part on fish egg and/or ovary Se concentrations.

Predictive modeling of selenium accumulation in brine shrimp in saline environments.

Great Salt Lake, Utah, is a large, terminal, hypersaline lake consisting of a northern more saline arm and a southern arm that is less saline. The southern arm supports a seasonally abundant fauna of low diversity consisting of brine shrimp (Artemia franciscana), 7 species of brine flies, and multiple species of algae. Although fish cannot survive in the main body of the lake, the lake is highly productive, and brine shrimp and brine fly populations support large numbers of migratory waterfowl and shorebirds, as well as resident waterfowl, shorebirds, and gulls.

Empirical estimation of biota exposure range for calculation of bioaccumulation parameters.

Bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) are frequently used to predict contaminant bioaccumulation in risk assessments. Development of these parameters is often hindered by uncertainty regarding the spatial scale of contaminant transfer from sediments to biota. We present a simple statistical method for optimizing bioaccumulation parameters (BAF and BSAF) in aquatic species, such as fish, whose exposure history may occur over broad spatial scales.