Area of Concern

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What is an AOC?

Area of Concern, or AOC, is the term used to identify hotspots on the Great Lakes where the environment has been harmed to the point that it affects the use and enjoyment of that area or the overall health of the lake or river.  Consequences of environmental degradation may include beach postings, loss of fish and wildlife habitat, loss of biodiversity, and restrictions on the amount of fish people can eat.

In 1987, the International Joint Commission (IJC) amended the Canada-U.S. Great Lakes Water Quality Agreement to recognize 43 AOCs in the Great Lakes Basin.  Of these 43 AOCs, 12 are Canadian, 26 are on the United States side, and 5 are considered “Binational” (e.g., the St. Marys River) as they are shared between Canada and the United States. As part of this agreement, remedial action plans (RAPs) have been developed for each area through a collaborative, methodical, and scientific approach.

Why is St. Marys River an AOC?

Pollution from industrial sources, such as effluents from the pulp and paper mill and steel production, insufficiently treated municipal and private sewage, and contaminated stormwater runoff from the surrounding watershed are all factors that have contributed to the degradation of the St. Marys River.  While inputs of pollution into the river are no longer as severe as they used to be, our legacy of environmentally harmful activities has left many negative effects on fish and their habitat, sediment composition, and the overall quality of the water.

Of the 14 environmental challenges (known as Beneficial Use Impairments or BUIs) outlined by the IJC as indictors of an Area of Concern, the St. Marys River is affected by 10.  For these 10 issues, 60 recommended remedial actions have been created that are needed in order to restore the health of the river.


Now you know about the problem, learn about the solution…visit the St. Marys River Remedial Action Plan by clicking here.