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Re-assessing the Degradation of Benthos Beneficial Use Impairment in the Toronto Harbour Area of Concern

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Title: Re-assessing the Degradation of Benthos Beneficial Use Impairment in the Toronto Harbour Area of Concern
Author: Stevack, Kathleen
Department: School of Environmental Sciences
Program: Environmental Sciences
Advisor: Sibley, Paul
Abstract: Contaminated sediment impedes restoration in many Great Lakes Areas of Concern (AOCs), including the Toronto and Region AOC. In this study, I assessed the “Degradation of Benthos” Beneficial Use Impairment within the Toronto AOC utilizing the sediment quality tetrad (SQTet). The SQTet includes four lines of evidence: sediment chemistry, bioaccumulation, toxicity, and benthic community structure. Sediment chemistry was comparable to nearshore reference areas, except for some elevated emerging contaminants. Laboratory toxicity bioassays indicated acute and chronic toxicity associated with point sources, supported by invertebrate body burdens measured in laboratory exposures. The benthic invertebrate community has generally shown increases in diversity over time, however sites impacted by point sources significantly differ from reference conditions and exhibit degraded communities. This concurrence among lines of evidence supports the conclusion that while overall AOC sediment and benthic conditions have improved through time, point sources to the waterfront continue to result in impaired conditions.
URI: http://hdl.handle.net/10214/17489
Date: 2019-09
Rights: Attribution-NonCommercial-NoDerivatives 4.0 International
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Attribution-NonCommercial-NoDerivatives 4.0 International Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 International