Date of this Version
A reconnaissance study was completed for the Riverton Reclamation Project (Riverton Project) in 1989 by Peterson et al. (1991) showed slightly elevated selenium concentrations in biota at several wetland sites. A follow-up investigation was initiated for the Department of Interior's National Irrigation Water Quality Program in 1994 to verify that selenium concentrations in biota were elevated above levels that cause adverse effects to aquatic migratory birds. Pondweed (Potamogeton vaginatus), aquatic invertebrates, bird eggs, and fish were collected from several wetlands managed by the Wyoming Game and Fish Department and analyzed for selenium and other trace elements. Selenium concentrations were lower in biota in 1994 than in 1988. However, aquatic invertebrates from all sites sampled except Ocean Lake were above the 3 μg/g dry weight dietary level known to cause adverse effects in fish and aquatic birds. American coot (Fulica americana) and eared grebe (Podiceps nigricolis) eggs from North Pavilion Pond had mean selenium concentrations of 10.9 and 13.1 μg/g, respectively, and did not differ appreciably from levels found in coot and grebe eggs in 1988.