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Sediment toxicity in mid-continent great rivers (USA)
Citation:
HARING, H. J., K. A. BLOCKSOM, MARK E. SMITH, M. C. Wratschko, B. Armstrong, T. R. ANGRADI, D. W. BOLGRIEN, AND J. M. LAZORCHAK. Sediment toxicity in mid-continent great rivers (USA). ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. Springer, New York, NY, 60(1):57-67, (2011).
Impact/Purpose:
Benthic organisms are in intimate contact with river sediments. Benthic assemblages are influenced by the physical and chemical properties of sediment. Sediment characteristics serve as exposure indicators for benthos, fish and other wildlife (e.g., sediment toxicity). Sediment toxicity samples were collected from selected sites on the Ohio River, Missouri River and upper Mississippi River as part of the 2004, 2005 and 2006 Environmental Monitoring and Assessment Program-Great Rivers Ecosystems Study (EMAP-GRE). Samples were collected by compositing sediment from 10 equally spaced transects across a 500 meter segment of river. The sediment samples were evaluated for toxicity using a Hyalella azteca 7-day lethality and growth, static-renewal test method test method.
Description:
In this study, 530 sediment samples were collected from 447 sites between 2004 and 2006 at randomly selected shoreline sites along the main channel of the Ohio, Missouri and Upper Mississippi Rivers as part of the Environmental Monitoring and Assessment Program for Great Rivers Ecosystems (EMAP-GRE). Based on the probability design these sites represented a total of 4721.4 km; 1329.2 km in the Upper Mississippi River, 1862.6 km in the Missouri River, and 1529.6 km in the Ohio River. Toxcity in sediment samples c ollected from these rivers were measured using a 7-day Hyallela azteca acute and chronic bioassay. Based on this bioassay, 65 sites were characterized as acutely toxic, whereas 130 sites exhibited chronic toxicity. Overall, 182 sites were characterized as toxic based on at least one endpoint, which include 52 acutely toxic only, 117 chronically toxic only and 13 toxic for both endpoints. Acute toxicity was observed in 15.9% of weighted segments representing 752.2 km of the Great Rivers reach. Chronic toxicity was observed in 27.4% of weighted river segments representing 1298.2 km. Either acute or chronic toxicity was observed at 40.0% of weighted river segments representing 1887.0 km. Toxic samples were analyzed for 21 pesticides, 20 PCB congeners and 6 polybrominated diphenyl ether (PBDE) congeners. The concentration levels for these analytes were below known toxicity thresholds for all samples. There was no strong correlation between un-ionized ammonia or osmotic stress as measured by conductivity and toxicity. Given these results, a toxicity identification evaluation (TIE) should be considered in future investigations to help identify potential toxic fractions that should be chemically analyzed.