Managing contaminated sediment

Overview

Contaminated sediment is a significant issue in many Great Lakes Areas of Concern (AOCs). These are locations within the Great Lakes identified as having experienced high levels of environmental harm. 

Contaminated sediments are typically the result of pollutants entering waterways, affecting water quality, fish and wildlife habitats, and surrounding communities. The environmental concerns in AOCs are referred to as Beneficial Use Impairments (BUIs). The BUIs that may be directly linked to contaminated sediment include:

The Government of Canada, the Province of Ontario, Indigenous communities, and local stakeholders (municipalities, port authorities, industries and non-government organizations) are developing and implementing sediment management strategies to address contaminated sediment in AOCs. These strategies will improve water quality and ecosystem health and ultimately lead to restoring beneficial uses in these AOCs.

Seventeen locations were formally recognized as AOCs by Canada, 12 in Canada and five binational AOCs that are shared by Canada and the United States.  Of these 17, 13 were identified as requiring management of contaminated sediment. To date, we have managed approximately 1.2 million cubic metres of contaminated sediment. Contaminated sediment management projects have been completed in:

An estimated 640,000 cubic metres of contaminated sediment remains. Currently work is being carried out to manage contaminated sediment in the St. Clair River, Hamilton Harbour, Port Hope Harbour, and Thunder Bay AOCs.

The map shows the location of  the Canadian Areas of Concerns around the Great Lakes basin: 12 are in Canada and 5 are shared by Canada and the United States. The map also shows the boundary of the Great Lakes basin.
Map of the 13 Canadian and binational AOCs in the Great Lakes basin and where contaminated sediment is or has been managed. 

Canadian AOCs and their respective sediment management status are as follows: On Lake Superior, Thunder Bay (active management), Jackfish Bay (natural recovery) and Peninsula Harbour (management complete). On the St. Marys River, which is a binational AOC shared by Canada and the United States (natural recovery). On Lake Huron, Spanish Harbour (natural recovery), Severn Sound (management complete) and Collingwood Harbour (management complete). On the Detroit River, which is a binational AOC shared by Canada and the United States (management complete). On the St. Clair River, which is a binational AOC shared by Canada and the United States (active management). Lake Erie has no AOCs requiring the management of contaminated sediment. The Niagara River is a binational AOC shared by Canada and the United States containing Lyons Creek East as a tributary (natural recovery). On Lake Ontario, Hamilton Harbour (active management) and Port Hope Harbour (active management). The St. Lawrence River is a binational AOC shared by Canada and the United States (natural recovery).

St. Clair River

The highly industrialized shoreline on the St. Clair River.
The highly industrialized shoreline on the St. Clair River, upstream of the three sediment management areas. Photo credit: St. Clair River Conservation Authority.

St. Clair River is a binational AOC. Years of industrialization, urbanization and agricultural land use activities have severely degraded water quality and ecosystem health in the river and its tributary watersheds.

Remedial actions to manage contaminated sediment and improve water quality in the river are underway. Since its designation as an AOC in 1987, 13,370 cubic metres of contaminated sediment has been cleaned up, with approximately 11,000 cubic metres remaining.

A detailed engineering design has been completed to cap the remaining priority areas of contaminated sediment in the St. Clair River.

Hamilton Harbour (Randle Reef)

Aerial photo of Randle Reef showing the first half of the active containment facility under construction in 2016.
The first half of the engineered containment facility being constructed in 2016. Barges shown are driving steel sheet piles into the harbour to form the double walled containment facility. Photo credit: McNally Construction. 

Randle Reef in the Hamilton Harbour AOC is the largest contaminated sediment site on the Canadian side of the Great Lakes. This contamination is the result of over 150 years of pollution from sources including coal, petroleum refining, steel production, municipal waste, sewage and overland drainage.

ECCC is leading a multi-partnered effort to manage approximately 615,000 cubic metres of contaminated sediment through the Randle Reef Sediment Remediation Project.  Construction began in 2015 and is expected to be completed in 2024.  The project, managed by Public Services and Procurement Canada, will:

Port Hope Harbour

The Port Hope Harbour and turning basin.

The Port Hope Harbour and turning basin. Photo credit: Canadian Nuclear Laboratories. 

The operation and waste management practices of Eldorado Mining and Refining between 1933 and 1953 contaminated an estimated 120,000 cubic metres of sediment with low-level radioactive material within the turning basin and west slip of Port Hope Harbour.

Remediation work in the harbour began in 2019, with an expected completion by 2023. The work is being managed by Canadian Nuclear Laboratories contracted to manage sites and facilities for Atomic Energy Canada Limited (AECL). The work includes strengthening harbour sheet pile walls, dredging contaminated sediment and disposing of it in a nearby specially-designed landfill.  For more information, visit the Port Hope Area Initiative.

Completing the harbour clean-up will restore all beneficial uses and the site can be removed from the list of AOCs.

Thunder Bay

A drill rig mounted on a barge in Thunder Bay harbour.

A drill rig mounted on a barge in Thunder Bay harbour used for sediment and environmental sampling. Photo credit: ECCC.

There is an estimated 390,000 cubic metres of contaminated sediment in the north end of Thunder Bay Harbour. The governments of Canada and Ontario and the Thunder Bay Port Authority recommended dredging to remove the sediment and construct an on-site confined disposal facility. Planning for the facility is currently underway.

Natural Recovery Sites

Natural recovery relies on natural physical, chemical and biological processes to isolate, reduce or remove the toxicity of contaminants. Long-term monitoring plans are in place to track natural recovery within the St. Lawrence River (Cornwall waterfront), Niagara River (Lyons Creek East) and Thunder Bay (Northern Wood Preservers) AOCs, as well as in the Spanish Harbour and Jackfish Bay AOCs in Recovery. 

Contaminated Sediment Management User Guide

The Evaluation of Project Designs for Contaminated Sediment Management User Guide is intended to help others evaluate engineering designs for various contaminated sediment management options. The guide was prepared by sediment remediation experts and combines current industry standards and knowledge with professional experience. 

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