Management of sediments 2016-2021

Assess the ecotoxicological risk and health risk of contaminated sediment sites in restoration projects

The assessment of the sediment quality will be performed in comparison with the criteria for assessing the quality of Quebec’s sediments. However, comprehensive assessment also requires the use of more specific tools for informing management decisions.

In the previous phases of the SLAP, our team determined the method to assess the risk related to the release of dredging sediments in free water for the St. Lawrence freshwater ecosystems. Furthermore, the analysis of actual cases allowed the development of risk assessment tools to be initiated for contaminated sediment sites. In order to assess the effects of this discharge on aquatic wildlife, the team analyzed the contaminants present in the sediments and then studied their effects by performing, among other, toxicity tests in the laboratory and studies on the invertebrate communities present in the St. Lawrence River.

During the new SLAP phase, our team will pursue its work throughout the St. Lawrence River. The creation of the necessary risk assessment tools for the ecosystems will be completed in the 2016-2021 phase, as will the risks of contaminated sediments on human health, which was initiated at the same time as the previous phase.

Determine the main environmental issues related to the presence of contaminated sediment sites in the St. Lawrence

This project aims to locate aquatic sites where the chemical quality of the St. Lawrence River’s sediments is of concern in accordance with the Criteria for the Assessment of Sediment Quality in Quebec and Application Frameworks: Prevention, Dredging and Remediation (2007). To do so, an analysis of the existing data and data collection on-site will be performed. This work will allow the extent of the different sectors of concern to be identified, assess their degree of contamination and to perform an initial assessment of the risk that contaminated sediments can have for the aquatic environment and its use (fishing, swimming, drinking water, etc.). The documentation of these contaminated sites will guide new data collection, determine the necessary environmental interventions, and set their order of priority to better guide future actions, if necessary.