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Monitoring dredging effectiveness using biological and chemical markers of exposure in brown bullheads and benthic macroinvertebrates
Citation:
MEIER, J. R., P. Baumann, J. M. LAZORCHAK, P. A. WERNSING, AND M. MILLS. Monitoring dredging effectiveness using biological and chemical markers of exposure in brown bullheads and benthic macroinvertebrates. Presented at 5th International Conference on Remediation of Contaminated Sediments, Jacksonville, FL, February 02 - 05, 2009.
Impact/Purpose:
Research to improve community-based health eco effects measurements, methods, and models; Federal, State, and Local managers can diagnose cause and forecast future condition in a scientifically defensible fashion to more effectively protect and restore valued ecosystems; Diagnosis: Managers and researchers understand links between human activities, natural dynamics, ecological stressors and ecosystem condition.
Description:
Sediments in portions of the Ashtabula River in Northeastern, Ohio are heavily contaminated with polychlorinated biphenyls (PCBs), and the river has been designated by the International Joint Commission as a Great Lakes Area of Concern (www.epa.gov/glnpo/aoc). Approximately 550,000 cubic yards of contaminated sediments were removed through remedial dredging. The primary objective for this field investigation was to evaluate surrogate and biological indicators in the biota and ecosystem in order to characterize contaminant exposure 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, and scoring external and histopathological lesions (including tumors) in the fish. Biomarker levels in indigenous fish were compared to those collected at a reference site, Conneaut Creek. Like the Ashtabula, the Conneaut receives both agricultural runoff and pollutants from ship traffic, but does not receive contaminants from industrial sources. DNA damage was measured using the Comet assay in brown bullhead catfish (Ameiurus nebulosus) collected by electrofishing. 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 dredging activities have been completed and the post-dredging characterization is currently underway. Results thus far show higher levels of DNA damage in both blood and liver of brown bullheads collected from the Ashtabula R. compared to Conneaut Cr.. An increase in DNA damage was seen in fish collected during dredging compared to pre-dredging suggesting an increase in exposure to contaminants during the dredging operations. Post-dredging samples have been collected and are being evaluated. When completed, the indicators 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.