You are here:
Assessing remediation of contaminated sediments using multiple biological endpoints: sediment toxicity, food web tissue contamination, biotic condition and DNA damage.
Citation:
Lazorchak, Jim, J. Meier, K. Fritz, H. Haring, M. Mills, P. Wernsing, D. Walters, J. Kraus, AND B. Armstrong. Assessing remediation of contaminated sediments using multiple biological endpoints: sediment toxicity, food web tissue contamination, biotic condition and DNA damage. SETAC World Congress, Orlando, FL, November 06 - 10, 2016.
Impact/Purpose:
This presentation will update our findings on the Ottawa River AOC by presenting data on fish tissue levels 5 years post sediment remediation. It provides evidence that GLNPO's efforts under GLLA and GLRI are working in reducing exposure levels to legacy organics such as PCBs and PAHs as well as some metals
Description:
The Ottawa River is a component of the Maumee River Area of Concern (AOC) as defined by the International Joint Commission’s Great Lakes Water Quality Agreement. A sediment remediation project took place in the lower 14.2 km of the river where urban and industrial activities impacted the river as a beneficial resource. 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 biological indicators were collected to assess the effectiveness of the remediation: fish from different trophic levels, macroinvertebrates and Tetragnathid spider tissue concentrations were analyzed: DNA damage was measured in Brown Bullhead blood; sediments were tested for toxicity using amphipod and midge 10-day survival/growth methods and macroinvertebrate biotic condition was assessed using OEPA Lacustrine Index of Community Integrity (LICI). The study area was divided into 3 river reaches with distinct hydrogeomorphology. Fish were collected using electroshocking and fyke net methods from each reach: Largemouth Bass, Brown Bullhead, White Sucker, Pumpkinseed, Gizzard Shad, Bluntnose Minnow and Emerald Shiner. Multi-plate samplers were deployed for collection of macroinvertebrates for tissue analyses and biotic condition assessment. Spiders were collected along the riparian zones of each macroinvertebrate HD site. DNA damage in Brown Bullhead increased during dredging then declined in subsequent years. Sediment concentrations of PCBs showed a significant decrease from pre dredge levels. Sediment toxicity was reduced within 1 yr post dredge for Hyalella azteca and 2-yrs post dredge for Chironomus dilutus as measured by survival. Gizzard Shad and Emerald Shiner showed lower tissue concentrations 3-yrs post dredging compared to pre-dredging across the entire project area. Five years post remedy macroinvertebrate and spider PCB tissue concentrations were below pre remedy level. 2015 fish tissue results will be presented. No difference in the LICI was found based on samples collected before and after dredging. 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.
