The Cornwall waterfront is contaminated with mercury and other legacy pollutants as a result of industrial activity over the last century. While industrial improvements and the closure of point-source polluters have decreased contaminant concentrations, sedimentary mercury remains at severely elevated levels. In aquatic environments, mercury can be converted to neurtoxic methylmercury and biomagnify through the food chain, causing impairments to ecological structure and function and impacts to human health. Effective mercury management relies on a comprehensive understanding of toxic ecosystem impacts, including long-term knowledge to understand baseline conditions, natural variability, and temporal history of contaminant impacts. Management also requires understanding how contaminants interact with other stressors to affect aquatic ecosystems. However, ecological monitoring in the Cornwall waterfront only began post-disturbance, and current toxicology tests do not consider environmental variability and other stressors. This study will employ a paleo-ecotoxicological framework to examine the influence of historic mercury and metal contamination on Cornwall waterfront ecology using chironomids as paleoindicators. The objectives are to assess the long-term ecological impacts of mercury and contaminant loading on chironomids from sediment cores and understand modern-day ecological impacts of mercury and other contaminants in the context of multiple stressors and environmental heterogeneity.
Armstrong Z, Moir K, Windle MJS, Ridal JJ, Cumming BF. (2021) Ecological change associated with historic industrial activity in the St. Lawrence River at Cornwall, ON: A paleo-ecotoxicological assessment using subfossil chironomid assemblages. Journal of Great Lakes Research, 47(4): 1074-1085.