Thunder Bay: Area of Concern

Thunder Bay, located on the north shore of Lake Superior and one of Canada’s largest inland shipping ports, was identified as an Area of Concern (AOC) in 1987. Today, through the efforts of Environment and Climate Change Canada and its partners, there have been significant improvements at this AOC.

Why was it listed as an Area of Concern?

Thunder Bay was designated as an AOC because a review of available data indicated that water quality and environmental health were severely degraded. There has been a long history of discharges into the harbour, primarily from the forest products industry (e.g., pulp and paper mills). Over the years, industrialization, dredging, waste disposal, the release of pollutants, and channelization (channels made in the area)  adversely impacted water quality and eliminated a significant amount of fish and wildlife habitat along the waterfront which resulted in ten of the Great Lakes Water Quality Agreement's 14 beneficial use indicators of ecological quality being deemed as impaired. 

What has been accomplished?

Through the combined efforts of Environment and Climate Change Canada, the Ontario Ministries of the Environment and Climate Change and Natural Resources and Forestry, local industry, concerned citizens and other partners, there has been significant improvements to water quality and ecosystem health in Thunder Bay. One of the original ten beneficial uses has been re-designated to “not impaired” status (added costs to agriculture or industry), and assessments underway are showing many others are not impaired and will soon be re-designated as well, including: degradation of fish and wildlife populations; fish tumours and other deformities; restrictions on dredging; degradation of aesthetics; and degradation of phyto- and zooplankton populations.

Through the collaborative efforts of industry and the Governments of Canada and Ontario, in 2005 contaminated sediments at the Northern Wood Preservers location in Thunder Bay Harbour were successfully remediated. During the $20 Million Northern Wood Preservers Alternative Remediation Concept (NOWPARC) project, 11 000 cubic metres of highly contaminated sediment were removed, treated and reused; 21 000 cubic metres of contaminated sediment were contained; the contaminated site was isolated with an 850-metre-long rock barrier; and 5 hectares of fish habitat were created. Assessments of the fish community around the NOWPARC site indicate the area now supports diverse and abundant fish populations.

All actions have been completed for municipal and industrial wastewater treatment. The implementation of federal and provincial pulp and paper regulations and the Province of Ontario’s Municipal Industrial Strategy for Abatement regulations in the mid-1990s resulted in improvements in mill processes and upgrades to wastewater treatment facilities at pulp and paper mills here and elsewhere on the Great Lakes. Upgrades in municipal wastewater treatment were also completed. Together, this resulted in improved water quality, fish habitat and fish populations.

The federal and provincial governments, working alongside local governments and other agencies completed many habitat rehabilitation projects in the AOC, including:

  • In 1991, increasing the abundanceof fish populations by building and rehabilitating fish spawning sites and nursery habitats in the Current River Estuary totaling 1700 square metres in area;
  • In 1993, restoring and creating aquatic habitat in five tributaries flowing into Thunder Bay Harbour, such as on the Current River, Kaministiquia River, and McIntyre/Neebing River, and creating island habitat at the mouth of McVicar Creek; and
  • In 1994, rehabilitating the littoral zone (the area close to the shore) in McKellar River by stabilizing wetlands and also planting more than 4000 native trees, shrubs and grasses near the mouth of the river, which created three hectares of wetland and more natural habitat for wildlife.

As a result of these and other initiatives, five beneficial uses are being evaluated for re-designation to “not impaired” status, because the original environmental concerns identified in the Remedial Action Plan have been addressed. These are: degradation of fish and wildlife populations; fish tumours and other deformities; restrictions on dredging; degradation of aesthetics; and degradation of phyto- and zooplankton populations. This will leave four beneficial uses to restore before Thunder Bay can be removed from the list of AOCs: restrictions on fish consumption; degradation of benthos; beach closings; and loss of fish/wildlife habitat.

What is left to do

Environment and Climate Change Canada and the Ontario Ministry of the Environment and Climate Change are working with local citizens and community, industry and other government partners to identify and address remaining environmental issues affecting the AOC.

The Remedial Action Plan will strive for further enhancements of fish and wildlife habitat in the AOC. With funding from the federal and provincial governments, EcoSuperior (a not-for-profit organization) has been implementing restoration work along the McIntyre River, including implementing Low Impact Design features in waterways to mitigate adverse impacts stormwater has on water quality and fish habitat.

Initiatives like this, and the City of Thunder Bay’s recent efforts to develop and implement a stormwater management plan, help mitigate non-point sources of pollution.

Completing the development of a contaminated sediment management strategy for the Thunder Bay North Harbour is also a priority.The area is currently contaminated with organic materials (wood fibres/pulp) and mercury. Extensive site investigations and an ecological and human health risk assessment have been completed, which represents a $1.5 Million investment with $550 000 coming from Environment and Climate Change Canada. Options for managing the contaminated sediment have been identified, and selection of a preferred option will help to finalize the plan.


Under the Canada-Ontario Agreement on Great Lakes Water Quality and Ecosystem Health, Canada and Ontario will continue to make significant progress towards remedial action implementation, environmental recovery and restoration of beneficial uses in the Thunder Bay AOC. It is anticipated that actions will be completed beyond 2020.


Efforts in Thunder Bay are undertaken in a partnership between the Government of Canada, other levels of government and non-government groups, including members of the public. 

Undertaking environmental restoration requires a large amount of scientific and technical expertise, local knowledge and hard work. One agency or group cannot engage in such a large task on its own without the help of others.

Listed below are participants that have contributed to efforts in Thunder Bay:

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