Aquatic ecological risk assessment frameworks in Canada: a case study using a single framework in South Baymouth, Ontario, Canada

Ecological risk assessment (ERA) is used to determine potential effect of human activities and industries on the natural environment. Numerous ERA management approaches exist and vary based on jurisdiction or ecological media. This ERA focused on contaminants within an aquatic ecosystem in sediments and surface water at South Baymouth port facility in Ontario, Canada. Contaminants were evaluated using the Canada-Ontario Decision-Making Framework for Assessment of Great Lakes Contaminated Sediments (COA). Following COA, this study (1) examined historical data from South Baymouth to determine contaminants of potential concern, (2) delineated potential contamination by comparing sediment and surface water concentration data to sediment quality guidelines and water quality guidelines from Canada and from different jurisdictions if Canadian guidelines were unavailable, (3) compared sediment concentrations to reference concentrations, and (4) developed an ERA decision matrix (used to inform management decisions at this aquatic site). Although sediments exhibited negligible potential for ecological risk and required no remedial management action, this case study highlights strengths of using COA for this ERA which included use of iterative and consistent approaches, but also highlights weaknesses which included unclear linkages between cause and effects of aquatic contaminants. Recommendations for future ERAs at contaminated aquatic sites include use of passive samplers and incorporating recent macroecology techniques.