TRACE ELEMENT CONCENTRATIONS IN PLANTS AND SEDIMENTS AT CRESCENT LAKE NATIONAL WILDLIFE REFUGE

Crescent Lake National Wildlife Refuge (NWR) is located in the Sandhills of western Nebraska, an area which contains the largest remaining tract of mid-grass and tall-grass prairie in North America. Land use surrounding the refuge is dominated by rangeland and land use practices likely result in minimal inputs of point or non-point source pollution. Industrial development in the area is minimal and the refuge complex is believed to be in fairly pristine condition. The use of persistent organochlorine pesticides on the refuge has been limited. The objectives of this study were to determine background concentrations of metals in biotic and abiotic components of the refuge and document these results to utilize as baseline information for reference and future contaminants investigations

BACKGROUND CONTAMINANTS EVALUATION OF FORT NIOBRARA AND VALENTINE NATIONAL WILDLIFE REFUGE

The objectives of this study were to determine background concentrations of metals and organic compounds in biotic and abiotic components of the Fort NiobraralValentine National Wildlife Refuge (NWR) Complex and document these results to utilize as baseline information for future contaminants investigations. To establish this baseline, sediment, water, and biotic samples (fish, double crested cormorant eggs, and vegetation) were collected from Fort Niobrara and Valentine National Wildlife Refuge in 1995 and tested for inorganic and organic contaminants. lnorganics were determined by inductively coupled plasma atomic emission spectrophotometer (lCP) scans. Arsenic and selenium were analyzed by atomic absorption spectrophotometry (AAS). Mercury levels were determined by cold vapor atomic absorption. Organochlorine scans were performed by capillary gas chromatography with an electron capture detector to determine organic contaminant levels. Elevated inorganic contaminant concentrations were detected in water, sediment, plant, and fish samples collected from each refuge. Only aluminum appeared elevated in water samples collected from Valentine NWR. Aluminum and arsenic appeared elevated at Fort Niobrara NWR. At Valentine NWR, elevated concentrations of metals in sediment were limited to one of the three sediment samples from Pelican Lake (Valentine NWR), which contained elevated levels in 11 of 19 metals analyzed. Aquatic plants collected from Valentine NWR showed very limited contamination; only boron was elevated in the common star duckweed collected from Marsh Lake. Concentrations of boron and selenium were elevated in aquatic macrophytes collected from Fort Niobrara NWR. Elevated concentrations of copper, molybdenum, and zinc were detected in fish collected from Valentine NWR. Concentrations of aluminum, copper, selenium, and zinc appeared elevated in fish collected from Fort Niobrara NWR. None of the concentrations detected in double~crested cormorant eggs appeared elevated. Concentrations of organics did not appear to be elevated in any of the media sampled from both refuges. The lack of intensive agriculture and absence of industrial development have likely allowed these refuges to remain in fairly pristine condition

A CONTAMINANTS EVALUATION OF THE BIG BLUE RIVER IN SOUTHEASTERN NEBRASKA

We collected three composite fish and three composite sediment samples from the Big Blue River in southeastern Nebraska to determine the presence of agricultural chemicals or other contaminants. Inorganic analyses consisted of individual analyses for arsenic, selenium, and mercury, as well as an ICP scan for other elements. Organic analyses included organochlorines, polynuclear aromatic hydrocarbons, organophosphate and carbamate pesticides, and chlorphenoxy acid herbicides. Arsenic was detected in the sediment samples, but not in the fish samples. Selenium was detected in one of three sediment samples and in all fish samples. Mercury was not detected in sediment samples, but was detected in all fish samples. Organic compounds detected in composite fish samples include BHC compounds, chlordane compounds, DDT and its metabolites, and anthracene. Outside of oil and grease, organic compounds were not detected in any sediment sample

A SURVEY OF ELEMENTAL CONTAMINANTS AND ORGANOCHLORINES AT NORTH PLATTE NATIONAL WILDLIFE REFUGE, NEBRASKA, 1993.

The North Platte National Wildlife Refuge (Refuge) is located 8 miles northeast of Scottsbluff, in Nebraska\u27s Panhandle. It was established by Executive Order in 1916, and was managed by the Bureau of Reclamation (BR) until 1986, when primary jurisdiction was granted to the U.S. Fish and Wildlife Service (Service). The 2,909 acre Refuge includes three reservoirs: 1) Lake Alice, 2) Winters Creek Lake, and 3) Lake Minitare (Figure 1). Water levels in all three reservoirs are managed by BR for irrigation and Lake Minitare is managed as a State Recreation Area under a lease agreement with the Nebraska Game and Parks Commission. The primary purpose of the Refuge is to provide sanctuary for migratory birds, but habitat for migrating bald eagles, waterfowl production, and compatible recreation are important management goals (USFWS, 2001). Twenty bald eagles and over 200,000 waterfowl concentrate on the Refuge during migration and over 200 species of birds have been observed on the Refuge. Irrigation supply water from the North Platte River is the primary source of water for all three Refuge reservoirs, which are interconnected by surface water. Lake Alice receives water from the Interstate and Highline canal, and discharges to the Supply canal and Hersche drain. Winters Creek Lake is fed by the Supply canal and also discharges to the Supply canal, with the inflow and outflow separated by approximately 200 meters. Lake Minitare receives water primarily from the Supply canal with secondary input from the Highline canal and discharges into the Lowline canal and Alliance drain. Land use in the drainage is primarily agricultural; with corn, soybeans, and sugar beet production the predominant row crops. In addition, alfalfa production and grazing areas support cattle ranching within the Refuge’s watershed

Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the North Platte Project area, Nebraska and Wyoming, 1995 /

Shipping list no.: 99-0168-P.Includes bibliographical references (p. 26-29).Mode of access: Internet