Location: Water Quality and Ecology Research
Title: Effects of contaminated sediments on a backwater restoration project in the Mississippi River Delta Authors
Submitted to: Journal International Environmental Application and Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 7, 2012
Publication Date: N/A
Interpretive Summary: Success of any aquatic restoration project is based on the assumptions that physical features can be manipulated in such a way as to improve habitat, water quality or both and that there is nothing inherent about the site that would prevent the project from succeeding. One potential impediment to restoration is pesticide contamination. Sediment samples were collected from three oxbow lake sites; two controls or comparison sites and one restoration site, as a part of a river backwater restoration project in the Mississippi Delta. Sediment was analyzed pesticide and metal contamination and tested for toxicity using a small freshwater crustacean. Fish were also sampled to see if any potential contamination had an affect on them. The results from the one of the control sites indicate that it was not a good site to measure success of our restoration project. The ecological data from this site pointed toward some type of impairment of its designated use of supporting fish and wildlife. While contaminates were found, further investigation is necessary to point to a specific stressor. This work shows the importance of conducting ecological analysis before selecting sites for restoration projects.
Technical Abstract: Success of any aquatic restoration project is based on the assumptions that physical features can be manipulated in such a way as to improve habitat, water quality or both. An additional assumption is that there is nothing inherent about the site that would prevent the target community from exploiting the newly restored habitat. Examples of inherent features that may cause restoration failure include barriers, contaminants or site instability. Because persistent pesticides continue to be reported as low-level contaminants in aquatic ecosystems in the lower Mississippi River alluvial plain, any site selected for restoration in this region of the United States should be tested for contamination. Sediment samples were collected from three backwater sites; two controls and one restoration, as a part of a river backwater restoration project in the Mississippi Delta. Sediment was analyzed for 7 metals, 15 persistent pesticides and 13 current-use pesticides and tested for toxicity using Hyalella azteca. Fish were also sampled at each site prior to restoration construction to establish baseline information on fish production and community structure. Analysis indicated that sediments from the control sites were more toxic than the restoration site and supported few numbers of fish.