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Results of EPA’s Assessment of Fish Tissue from U.S. Rivers for Selenium with Implications for Aquatic Life and Human Health
Citation:
Lazorchak, Jim, J. Wathen, Tony Olsen, L. Stahl, Tom Kincaid, H. McCarty, A. Batt, AND B. Snyder. Results of EPA’s Assessment of Fish Tissue from U.S. Rivers for Selenium with Implications for Aquatic Life and Human Health. SETAC North America, Vancouver, BC, CANADA, November 09 - 13, 2014.
Impact/Purpose:
This abstract is an overview of the Selenium analyses of fish collected in the 2008-2009 NRSA study
Description:
EPA’s Office of Water and Office of Research and Development collaborated to conduct the first statistically based survey of contaminants in fish fillets from U.S. rivers. This national fish survey was conducted under the framework of EPA’s National Rivers and Streams Assessment (NRSA), a probability-based survey designed to assess the condition of the Nation’s streams and rivers. During June through October of 2008 and 2009, field teams applied consistent methods nationwide to collect samples of fish commonly consumed by humans at 542 randomly selected river locations (≥ 5th order based on 1:100,000-scale Strahler order) in the lower 48 states. They collected one fish composite sample at every sampling location, with each composite consisting of five similarly sized adult fish of the same species from a list of target species. Largemouth and smallmouth bass were the primary species collected for the study, accounting for 34% and 24% of all fish composites, respectively. Samples were collected from both non-urban (379 sites) and urban locations (163 sites). Each composite sample was homogenized and analyzed using an ICP method for total selenium. None of the samples exceeded or were close to EPA’s draft Ambient Aquatic life Criteria for muscle tissue, 11,800 ng/g or the human health screening value (chronic toxicity) of ~6,000 ng/g wet weight. Six samples were at or near the U.S. Department of Interior’s 1998 guideline for dietary intake of birds, 3,000 ng/g dry weight or 2,400 ng/g wet weight. The maximum sample value was 2,657 ng/g and lowest value of 51 ng/g which was above the MDL of 18 ng/g. The national estimated weighted mean value was 849 ng/g. Urban and non-urban sites mean values were 774 and 867 ng/g, respectively. Ecoregional values for Plains Lowlands, Eastern Highlands and Western Mountains were 848, 773, and 1058 ng/g. For major groups of fish, Sunfish, Catfish, Smallmouth Bass, Largemouth Bass, Trout, and Perches, mean values were 773, 628, 775, 566, 2,500, and 705 ng/g.