Mapping mercury hot spots in sediments: Cornwall waterfront

Mercury “hot spots” along the Cornwall waterfront.

Photo: St. Lawrence River Institute of Environmental Sciences.

2014-2015 Funding: $22,500, including $7,500 provided by the Great Lakes Sustainability Fund

Other Project Contributors: Environment and Climate Change Canada, Ontario Ministry of the Environment and Climate Change, St. Lawrence River Institute of Environmental Sciences, University of Ottawa, and St. Lawrence River Remedial Action Plan.

Researchers are gaining a better understanding of mercury “hot spots” along the Cornwall waterfront, with the support of the Great Lakes Sustainability Fund.

Their findings will provide critical new input into efforts to manage the legacy of pollution from more than a century of industrial and municipal activities along the St. Lawrence River in Cornwall. The river was severely degraded by contaminants from chemical manufacturing, pulp and paper production, oil storage and textile manufacturing. The production of these contaminants has ceased, though the presence of mercury, which accumulated in three main zones downstream of major sources, remains a concern.

The Cornwall Sediment Strategy and related Administrative Controls Protocol pull together the efforts of federal, provincial and municipal governments, the Raisin Region Conservation Authority and the Mohawk Council of Akwesasne. The parties have agreed that natural recovery is the most appropriate method for dealing with the contaminated sediments found along the Cornwall waterfront. A key objective is to ensure measures are in place to prevent any future disturbance, exposure or re-suspension of contaminated sediments - for example, as a result of new housing construction along the waterfront or the installation of new docks.

That goal, in turn, requires a solid understanding of where the mercury contamination is located, at what depths and in what kinds of sediment. To address gaps in current data, researchers under the direction of the St. Lawrence River Institute of Environmental Sciences carried out sampling in areas of the three contaminated zones within 10 metres of shore that had not been previously sampled. The results will help the Strategy parties decide whether additional control measures are needed in the shoreline areas of highest contamination. 

The project also has helped build awareness of the Cornwall Sediment Strategy among community residents. All property owners along the Cornwall waterfront adjacent to the contaminated zones were contacted as part of the project. They were provided background information on the strategy and invited to a public meeting where the project was discussed and initial results presented. The public meeting was well attended and residents expressed strong support for the research project.

For more information on the St. Lawrence River (Cornwall) Area of Concern, please visit: Raisin Region Conservation Authority.

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