EVALUATION OF WETLANDS CREATED WITH EFFLUENT FROM A SWINE CONCENTRATED ANIMAL FEEDING OPERATION USING MALLARD SENTINELS: IMPLICATIONS FOR MCMURTREY NATIONAL WILDLIFE REFUGE

Previous work by the U.S. Fish and Wildlife Service identified nutrients, elemental contaminants, algal toxins, bacterial pathogens, and hormones as contaminants of concern (COCs) associated with wetlands created from the secondary effluent of a large swine concentrated animal feeding operation. In this follow-up study, COC exposure and effects to waterfowl were evaluated using game farm mallards. Mallards were kept in enclosures built on two created wetlands (treatment sites) and two reference wetlands that are federally managed for waterfowl habitat. Water quality in the created wetland enclosures had higher specific conductivity, BOD, turbidity, pH, and nutrients than reference wetlands. Algal blooms frequently occurred in the created wetlands and included Microcystis spp. All sentinel mallards tested negative for duck plague and avian influenza; however, an avian botulism outbreak on the created wetlands occurred in August of 2003 after the study was completed. Cumulative stress from poor water quality and reproduction may have caused hen mortality in the created wetland enclosures, resulting in a greater survival to hatch in the reference wetlands compared to created wetlands. However, wild brood production was observed in the created wetlands. There were no significant differences in sentinel mallard blood plasma chemistry and histology biomarkers between reference and created wetland enclosures. Known toxicity thresholds were only exceeded for selenium concentrations in liver, and included sentinel mallards on reference and created wetland enclosures. It is recommended that a constructed wetland system is developed to further treat Hastings Pork secondary swine wastewater before it is delivered to habitat wetlands for migratory waterfowl

ASSESSMENT OF SELENIUM AND ATRAZINE EXPOSURE AND EFFECTS TO WILDLIFE AT THE NORTH PLATTE NATIONAL WILDLIFE REFUGE, SCOTTSBLUFF, NEBRASKA

This study evaluated selenium and atrazine exposure and effects to fish and wildlife at North Platte National Wildlife Refuge (Refuge) in Scotts Bluff County, Nebraska. Atrazine was detected in 2 of 54 water samples and at low concentrations that are not of concern. However, concentrations of selenium and strontium exceeded toxicity guidelines in water, sediment, invertebrates, whole-body fish and wood duck eggs. Concentrations of selenium in water at Refuge sites frequently exceeded a 2 μg/L total recoverable threshold for selenium bioaccumulation and were greatest at Stateline Island (9.7 μg/L) and Little Lake Alice (24 μg/L). In sediments, strontium concentrations were elevated above background (49 mg/kg) at all sites but were greatest at Stateline Island (858 mg/kg). Selenium in sediments was greatest at Stateline Island (mean = 9.6 ± 2.1 mg/kg) and exceeded a 4 mg/kg toxicity guideline at which adverse effects to some fish and wildlife species may occur. Concentrations of selenium in aquatic invertebrates averaged 10 ± 2 mg/kg at Stateline Island and 6 ± 2 mg/kg at Winters Creek Lake and exceeded a 3 - 8 mg/kg dietary benchmark for reproductive impairment in birds. Fish from all sites had tissue selenium concentrations above a 4 mg/kg effects threshold for protecting fish health and reproduction. Twenty-nine of 40 fish sampled also exceeded a 2 mg/kg wet weight human health advisory for limited consumption. Concentrations of selenium in wood duck eggs at Lake Alice and Lake Minatare averaged 5.9 ± 0.6 and 6.4 ± 0.3 mg/kg, respectively, and 20 of 42 eggs exceeded a 6 mg/kg toxicity threshold for reduced hatchability. An aquatic hazard assessment of selenium for each Refuge subunit was derived using a protocol that considers selenium concentrations in water, sediments, invertebrates, fish and bird eggs. This assessment indicates high risk to Refuge biota from selenium exposure at Winters Creek Lake and Stateline Island and moderate risk at Lake Alice and Lake Minatare. Recommendations to reduce selenium exposure include management actions aimed at increasing selenium volatilization and phytoremediation

CONTAMINANT EXPOSURE AND REPRODUCTIVE HEALTH OF SANDHILL CRANES IN THE CENTRAL PLATTE RIVER VALLEY, NEBRASKA.

The central Platte River Valley provides crucial staging habitat for the endangered whooping crane (Grus americana) and the mid-continent population of sandhill cranes (Grus canadensis). Platte River flow depletions and the conversion of native wet meadows for agriculture and other purposes has decreased the cranes natural habitat in the central Platte River Valley, and waste corn now makes up most of the cranes diet while they are in the Valley. The purpose of this research was to measure organochlorine, elemental contaminant, and pesticide exposure to sandhill cranes from the central Platte River Valley, and to evaluate their reproductive condition. Pesticides and organochlorines were measured in soil and waste corn samples collected from cornfields where sandhill cranes foraged. Elemental and/or organochlorine contaminants were measured in sandhill crane carcass, liver, brain, muscle, and kidney tissues. Reproduction in sandhill cranes was evaluated by measuring sex steroids in blood plasma and by histological examination of gonads. Sandhill cranes collected from the central Platte River Valley in 1999 and 2001 appeared to be in normal reproductive condition and concentrations of organochlorines in their tissues were not at levels considered harmful. In addition, pesticides in corn and soil from cornfields were all below detection. Elemental contaminants measured in crane tissues also were generally low, with the exception of boron. Concentrations of boron in sandhill crane livers (n = 7) averaged 43.60 ± 3.59 mg/kg dw and exceeded reproductive toxicity thresholds established for mallards. Boron concentrations also were detected at higher concentrations than previously reported in sandhill crane livers analyzed ten years earlier in the same study area. More research is needed to identify sources of boron in the area and further evaluate whether boron exposure to sandhill cranes may be adversely affecting their reproductive potential

A HEALTH RISK EVALUATION FOR PALLID STURGEON (\u3ci\u3eSCAPHIRHYNCHUS ALBUS\u3c/i\u3e) IN THE LOWER PLATTE RIVER USING SHOVELNOSE STURGEON (\u3ci\u3eSCAPHIRHYNCHUS PLATORYNCHUS\u3c/i\u3e) AS A SURROGATE

Most sturgeon species worldwide have been in steep decline since the 1900s. This research evaluated shovelnose sturgeon health, reproduction, and exposure to environmental contamination in the lower Platte River. Shovelnose sturgeon served as a surrogate species for the endangered pallid sturgeon and their health was assessed by incorporating measurements of general health with hepatic, immune, and reproductive system biomarkers. Environmental contaminants were measured in water, potential pallid sturgeon food items (cyprinid minnows), and shovelnose sturgeon digesta, liver, and blood plasma. Contaminants detected in shovelnose sturgeon at concentrations of concern included PCBs, selenium, and atrazine. Total PCBs in carcasses (n = 8) averaged 0.32 μg/g ww. Selenium averaged 4.8 μg/g dw in carcasses (n = 30) and 80 percent of individuals sampled were within the 4 to 6 μg/g threshold range for reproductive impairment in sensitive fish species. Pallid sturgeon food items had significantly (p \u3c 0.05) greater concentrations of Hg, Se, and Zn than shovelnose sturgeon digesta. Atrazine was detected in all blood plasma samples analyzed (n = 50) at concentrations from 0.24 to 28 μg/L, but was not detected in liver (n = 19). Although the effects of atrazine exposure to shovelnose sturgeon are unknown, results of this study and previous work by others indicate that it may be disrupting steroidogeneisis. Gross observations and condition indices seem to indicate that shovelnose sturgeon from the lower Platte River are healthy; however, reproductive biomarkers and histological examination of gonads indicate potential reproductive impairment as indicated by ovicular atresia, abnormal estrogen to testosterone ratios, and high concentrations of vitellogenin in males. Pallid sturgeon may be especially at risk to contaminants in the lower Platte River that bioaccumulate and cause reproductive impairment because they have a more piscivourus diet, greater maximum life-span, and a longer reproductive cycle than shovelnose sturgeon. Strategies to reduce shovelnose sturgeon and pallid sturgeon exposure to environmental contaminants in the lower Platte River are presented