Abstract Sediment quality of the Toronto and Region Area of Concern (AOC) waterfront was assessed using a weight of evidence approach following the Sediment Quality Triad, with the addition of contaminant bioaccumulation data, to determine current status following the 2013 re-designation of the “degradation of benthos” Beneficial Use Impairment as “no longer impaired.” Five stations within the AOC were sampled in 2015 and compared to lower Great Lakes nearshore reference areas (n = 22) selected based on similarity of sediment physicochemical properties. Sediment chemistry was comparable except for a localized instance of elevated perfluorinated compounds at one AOC site. Laboratory sediment toxicity bioassays indicated chronic toxicity associated with point sources to the AOC, corresponding to increased invertebrate body burdens measured in laboratory exposures. Diversity metrics and multivariate analysis showed that benthic invertebrate community composition present at the AOC sites was not significantly different from reference conditions of the lower Great Lakes. The weight of evidence from this study indicates benthic invertebrate communities continue to show effects of degraded sediment conditions at sites impacted by point sources. While the 2013 RAP decision was to re-designate the “degradation of benthos” BUI to “no longer impaired,” our results support the notion that life after AOC delisting must continue to prioritize monitoring efforts.

中文翻译：

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重新评估多伦多和关注区域的底栖生物有益使用损害的退化

摘要 多伦多和关注区域 (AOC) 滨水区的沉积物质量按照沉积物质量三元组使用证据权重方法进行评估，并添加污染物生物累积数据，以确定在 2013 年重新指定“底栖生物的退化” 有益使用损害“不再受到损害”。2015 年对 AOC 内的五个站点进行了采样，并与根据沉积物物理化学特性的相似性选择的大湖下游近岸参考区（n = 22）进行了比较。除了在一个 AOC 地点发生全氟化合物升高的局部情况外，沉积物化学性质相当。实验室沉积物毒性生物测定表明与 AOC 的点源相关的慢性毒性，对应于实验室暴露中测量的无脊椎动物身体负担的增加。多样性指标和多变量分析表明，AOC 地点的底栖无脊椎动物群落组成与五大湖下游的参考条件没有显着差异。这项研究的证据权重表明，在受点源影响的地点，底栖无脊椎动物群落继续表现出退化沉积物条件的影响。虽然 2013 年 RAP 决定将“底栖生物退化”BUI 重新指定为“不再受损”，但我们的结果支持这样的观点，即 AOC 退市后的生活必须继续优先考虑监测工作。多样性指标和多变量分析表明，AOC 地点的底栖无脊椎动物群落组成与五大湖下游的参考条件没有显着差异。这项研究的证据权重表明，在受点源影响的地点，底栖无脊椎动物群落继续表现出退化沉积物条件的影响。虽然 2013 年 RAP 决定将“底栖生物退化”BUI 重新指定为“不再受损”，但我们的结果支持这样的观点，即 AOC 退市后的生活必须继续优先考虑监测工作。多样性指标和多变量分析表明，AOC 地点的底栖无脊椎动物群落组成与五大湖下游的参考条件没有显着差异。这项研究的证据权重表明，在受点源影响的地点，底栖无脊椎动物群落继续表现出退化沉积物条件的影响。虽然 2013 年 RAP 决定将“底栖生物退化”BUI 重新指定为“不再受损”，但我们的结果支持这样的观点，即 AOC 退市后的生活必须继续优先考虑监测工作。