Spanish Harbour AOC recovery monitoring

Spanish Harbour was identified as an Area of Concern (AOC) due to degraded water quality and environmental health and was recognized as an Area in Recovery in 1999. As part of the Great Lakes Action Plan, assessments of benthic conditions in Spanish Harbour have been conducted periodically since 2003. Using information from three assessment components – sediment chemistry, sediment toxicity, and benthic community structure – overall and assessment component-specific conditions were determined based on the Canada-Ontario Decision Making Framework for the Assessment of Contaminated Sediments in the Great Lakes. Results from these assessments are used by ECCC and MECP AOC risk managers to evaluate sediment management plans. The last benthic assessment of Spanish Harbour in 2013 indicated continuing adverse conditions, particularly in two depositional areas in the Whalesback Channel and North of Aird Island. These included sediment toxicity and altered benthic communities. Most conditions have been stable over the 2003-2013 period. The delisting criteria for Spanish Harbour were revised in 2019 to that based on improving conditions/trends, as measured by contaminant concentrations in sediment, benthic community health, and sediment toxicity. This is to be determined through continued monitoring of this Area in Recovery. Conclusive evidence of positive trends could provide the data necessary to meet the delisting criteria. This project supports the Spanish Harbour monitoring activities required in order to meet the delisting criteria. The objectives of the 2021 study were to: 1) Assess benthic conditions including sediment contaminant concentrations, sediment toxicity, and benthic invertebrate community structure; 2) Determine whether conditions are significantly different than reference conditions and, if so, to what degree and spatial extent; and 3) Evaluate whether benthic conditions continue to show positive trends over time to meet the recently revised delisting criteria.