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Assessing remediation of contaminated sediments on the Ottawa River using chemical and biological endpoints (Big Rivers Ecology Course)
Citation:
Lazorchak, Jim, K. Fritz, J. Meier, H. Haring, R. Yeardley, M. Mills, P. Wernsing, D. Walters, R. Otter, B. Armstrong, AND J. Kraus. Assessing remediation of contaminated sediments on the Ottawa River using chemical and biological endpoints (Big Rivers Ecology Course). Big Rivers Ecology Course, Thomas More Field Station, KY, July 30, 2018.
Impact/Purpose:
Presents research conducted under SHC 3.63 on evaluation of remedy effectiveness.
Description:
The Ottawa River is a component of the Maumee, Ohio Area of Concern (AOC) as defined by Great Lakes Water Quality Agreement between the U.S. and Canada. A Great Lakes Legacy Act sediment remediation project took place in the lower 14.2 km of the river where urban and industrial activities impacted the the river, resulting in a number of beneficial use impairments (BUIs). Sediment was removed based on a surface weighted average concentration model where PCB and PAH levels exceeded targeted levels. Each year from 2009-2013 and again in 2015, various lines of evidence, including biological indicators and chemical analyses (PCB/PAH sediment/water) were collected to assess the effectiveness of the remedy. Biological indicators were: 1) fish from different trophic levels (Largemouth Bass, Brown Bullhead, White Sucker, Pumpkinseed, Gizzard Shad, Bluntnose Minnow, Emerald Shiner), macroinvertebrates (collected with multi-plate samplers), and tetragnathid spider tissue concentrations. These organisms were analyzed for PCB and PAH concentrations; 2) DNA damage was measured in Brown Bullhead blood; 3) Sediment toxicity using Chironomus dilutus and Hyalella azteca; 4) Macroinvertebrate biotic condition was primarily assessed using Ohio’s multi-metric Lacustrine Index of Community Integrity (LICI). Results: DNA damage in brown bullhead increased during dredging then declined in subsequent years. Sediment showed a reduction in acute toxicity post-remedy (2015) for both test species; Based upon one measure of biotic integrity (LICI), no difference was found pre-and post-dredge, though other metrics/ analyses will be explored. Unlike PCBs, whose concentration decreased 5 years post-dredge in Gizzard Shad, Emerald Shiners, Bluntnose Minnows, Largemouth Bass, macroinvertebrate and spiders, there was no significant change in PAH tissue concentrations. For example, levels of total priority PAHs did not change pre- and 5 years post-dredge for PAHS in water, sediment, brown bullheads, and emerald shiners. Levels of PAHs in macroinvertebrates were lower pre-dredge, and levels of PAHs in bluntnose minnow were lower 5 years post-dredge. A likely contributing factor to the contaminant-specific results is that, at this site PCBs are mostly legacy contaminants, while there are still nearby sources that can still be introducing PAHs into the river in significant amounts. Consumption limits for Largemouth bass went from “No consumption” pre-remedy to one meal/month and for sunfish to one meal/week 5 years post-remedy. 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).