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A weight of evidence approach for assessing remediation of contaminated sediments using food web tissue contamination, biotic condition and DNA damage
Citation:
Lazorchak, Jim, J. Meier, K. Fritz, M. Mills, P. Wernsing, H. Haring, D. Walters, J. Kraus, AND B. Armstrong. A weight of evidence approach for assessing remediation of contaminated sediments using food web tissue contamination, biotic condition and DNA damage. SETAC Europe, Nantes, FRANCE, May 22 - 26, 2016.
Impact/Purpose:
This presentation provides an overview of the biological line of evidence related to a remediation project where we looked at pre, during and 3 & 5 years post dredging. Its one of the 3 Rs Remediation, Restoration and Revitatization.
Description:
The Ottawa River lies in extreme northwest Ohio, flowing into Lake Erie’s western basin at the city of Toledo. The Ottawa River is a component of the Maumee River Area of Concern (AOC) as defined by the International Joint Commission. In 2009-2010 a sediment remediation project took place in the lower 8.8 miles of the river where urban and industrial activities impacted the river as a beneficial resource. Sediment was removed at designated locations based on a surface weighted average concentration model where PCB and PAH levels exceeded targeted levels. This presentation will focus on three biological tools: assessing response of tissue concentrations of PCBs and PAHs, DNA damage in Brown Bullhead and macroinvertebrate biotic condition as measured by Ohio EPA Lacustrine Index of Community Integrity (LICI). From 2009-2013 and again in 2015, pre- and post-remedy sampling of fishes representative of different trophic levels was conducted via electroshocking and fyke net sampling. The study area was divided into 3 river reaches (reaches 2, 3, & 4 numbered from down- to upstream). Fish were collected by electro-shocking or fyke netting across an entire reach where Largemouth Bass, Brown Bullhead, White Sucker, Pumpkinseed, Gizzard Shad, Bluntnose Minnow and Emerald Shiner. Blood samples were collected from 10 Brown Bullheads from each reach and processed in the field and laboratory using Comet Assay methods.Two different configurations of multiplate samplers (Hester Dendies; HD) were used for collection of macroinvertebrates for tissue analyses: a 9 plate, 3X3 inch assembly and an 11 plate 5X5 inch assembly. The 9 plate assembly was also used for macroinvertebrate biotic condition assessment. DNA damage in Brown Bullhead increased during dredging then declined in subsequent years. Largemouth Bass, White Sucker, Brown Bullhead, Pumpkinseed, Bluntnose Minnow, macroinvertebrates & spider tissue concentrations showed no change compared to pre-dredging. Gizzard Shad and Emerald Shiner showed lower tissue concentrations compared to pre-dredging across the entire project area. No change in the LICI was found in the before and post dredging measures of LICI. Based on modeling performed during the design phase, it was anticipated that the long-term clean up goals would be met approximately 10 years after the completion of dredging activities, by 2020.
