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Presentation: Assessing Remedy Effectiveness of Contaminated Sediments using Brown Bullheads and Benthic macroinvertebrates to contaminated sediments in the Ashtabula River before, during and after dredging
Citation:
Lazorchak, Jim, J. Meier, M. Mills, P. Wernsing, AND P. Baumann. Presentation: Assessing Remedy Effectiveness of Contaminated Sediments using Brown Bullheads and Benthic macroinvertebrates to contaminated sediments in the Ashtabula River before, during and after dredging. Presented at SETAC, Long Beach, CA, November 11 - 15, 2012.
Impact/Purpose:
This is an abstract of results from our RAP project on contaminanted sediments. I have included the actual presentation for review as well
Description:
The Ashtabula River in Northeastern, Ohio has been designated by the International Joint Commission as a Great Lakes Area of Concern (www.epa.gov/glnpo/aoc), based on the listing of six beneficial use impairments (out of 14 possible) in the lower two miles of the river. In 2007, approximately 550,000 cubic yards of contaminated sediments were removed through remedial dredging. The primary objective of this field investigation was to monitor contaminant exposure in selected biota before, during, and following dredging. This was done by measuring PCB and PAH accumulation in whole fish tissue (brown bullheads) and in benthic macroinvertebrates, assessing changes in DNA damage in liver and blood of the fish, and scoring external and histopathological lesions (including tumors) in the fish. Sediment and water samples were also collected in conjunction with the biological sampling to evaluate contaminant residuals. Levels of DNA damage in indigenous brown bullheads were measured using the Comet assay and compared to levels in fish collected at a reference site, Conneaut Creek. Benthic macroinvertebrates were collected using Hester-Dendy artificial substrates by deployment at three locations in the dredge area as well as at an upstream reference site. The pre- and during-dredging characterizations have been completed and four years of post-dredging data have been collected. Results thus far confirm a reduction in fish tissue and macroinvertebrate levels of PCB and PAHs following dredging, indicating the effectiveness of the remediation in reducing exposure of biota to the primary contaminants of concern. Similarly, although initially higher in fish collected pre- and during- dredging, DNA damage levels in the Ashtabula fish post-dredging are similar to those seen in fish collected from the Conneaut reference site. When completed, the methods used in this study can be used by regulatory agencies, remedial project managers, and dredging practitioners to evaluate and assess the effectiveness of environmentally-prudent remediation techniques for contaminated sediment sites around the country. Although this work was reviewed by USEPA and approved for publication, it may not necessarily reflect Agency policy