Funding Program: Contaminant Biology

Statement of Problem: The 2,909-acre North Platte National Wildlife Refuge (Refuge) was established by Executive Order in 1916 and is located 8 miles northeast of Scottsbluff, in Nebraska's Panhandle. The Refuge is located in an agriculturally dominated landscape where corn, bean, and sugar beet are the predominant row crops. The U.S. Fish and Wildlife Service (Service) in 1985 obtained primary jurisdiction of the Refuge subject to Bureau of Reclamation (BR) uses for irrigation (USFWS, 2001). There are four dispersed sub-units on the Refuge, which includes three reservoirs and one island. These sub-units are: 1) Lake Alice, 2) Winters Creek Lake, 3) Lake Minatare, and 4) Stateline Island. Lake Minatare is managed under a lease agreement with the Nebraska Game and Parks Commission (NGPC) as a State recreation area. The Refuge was established primarily to provide sanctuary for migratory birds; however, habitat for migrating bald eagles, waterfowl production, and compatible recreation are important management goals (USFWS, 2001). Twenty bald eagles and over 200,000 waterfowl utilize the Refuge during migration, and more than 200 species of birds have been observed. Waterfowl species that nest at the Refuge include mallard (Anas platyrhynchos), Canada goose (Branta canadensis) blue-winged teal (Anas discors), and wood duck (Aix sponsa). A Contaminants Assessment Process (CAP) completed in 2001 by the Service identified selenium (Se) and atrazine as contaminants that may adversely affect fish and wildlife resources. These findings were based on irrigation drainage water quality surveys in the area (Druliner et al., 1999; Schwarz and Esmoil 2004, draft final report) and recent research that implicates atrazine as likely causing endocrine disruption in amphibians (Reed et al., 1998; Hayes et al., 2002a, 2002b; Tavera Mendoza et al., 2002a, 2002b) and fish (Moore and Waring, 1998; Saglio and Trijasse, 1998; Moore and Lower, 2001). Selenium likely enters the Refuge from irrigation drainage canals and atrazine may enter the Refuge from irrigation drainage canals and direct agricultural run-off. The purpose of the proposed research is to follow-up on the Refuge CAP review by evaluating Se and atrazine exposure and effects to wildlife that utilize the refuge. Concentrations of Se will be measured in six ecosystem components (i.e., water, sediment, invertebrate, plant, fish, and avian). Uptake and potential cumulative adverse effects from wildlife exposure to Se and other prominent irrigation drainage contaminants including boron, arsenic, copper, zinc, mercury, molybdenum, and salinity will be evaluated. Concentrations of atrazine in water and amphibian blood plasma samples will be measured and compared to the frequency of gonadal abnormalities as determined by histology. Atrazine exposure and potential effects to amphibians will be compared among Refuge subunits and the relatively pristine Crescent Lake National Wildlife Refuge (CLNWR).

Objectives: The primary goal of the proposed research is to evaluate selenium and atrazine exposure and effects to fish, amphibians, and waterfowl that utilize the Refuge. The following subordinate objectives will be met to investigate selenium exposure and effects to wildlife on the Refuge: 1.Measure selenium concentrations and total organic content in Refuge sediments. 2.Measure total recoverable selenium in Refuge water. 3.Measure selenium concentrations in refuge biota including, whole body fish, waterfowl food items (invertebrates and plants) and duck eggs. 4.Assess potential adverse effects of selenium exposure to Refuge wildlife by comparing biota tissue concentrations to effects concentrations established in the literature. The subordinate objectives to evaluate atrazine exposure and potential effects to wildlife at North Platte National Wildlife Refuge and Crescent Lake National Wildlife Refuge include: 1.Monitor atrazine concentrations, DO, specific conductance, salinity and turbidity in surface water. 2.Measure triazine pesticide concentrations in whole body tadpoles and newly metamorphosed amphibians. 3.Assess potential atrazine effects (hermaphroditism) in amphibians by histological examination of gonads.