Peninsula Harbour Marathon, courtesy Environment Canada

Peninsula Harbour is on the north shore of Lake Superior. It is one of 43 designated Areas of Concern (AOC) on the Great Lakes. It includes approximately 12 kilometres of shoreline, including the Town of Marathon’s waterfront, and extends four kilometres into Lake Superior. Capping contaminated sediment is the last step in the clean-up process of Peninsula Harbour.

Environmental challenges
The Town of Marathon grew in the 1940s and 50s around a thriving pulp and paper mill at the edge of the water. When the mill started, there were no environmental regulations, and no controls on pollution. The mill discharged raw wastewater directly to the harbour. The town’s wastewater treatment plant also discharged sewage directly to the lake until the town built a secondary treatment plant in the 1970s.

With high levels of bacteria and nutrients, the wastewater caused poor water quality and affected habitat for fish and other aquatic organisms. Contaminants, like mercury from the chemical plant and PCBs from mill operations, settled and contaminated sediment in the harbour as far as a kilometre from the shoreline. The contaminants taken in by the organisms that live in the water eventually accumulate in fish tissues. The Guide to Eating Ontario Sport Fish advises people to eat fewer fish from Peninsula Harbour than most other areas of Lake Superior.

Taking action
Peninsula Harbour was designated as an AOC in 1987 under the Canada-U.S. Great Lakes Water Quality Agreement.

Ontario and Canada work with local communities to create and implement Remedial Action Plans (RAPs) to restore Canadian AOCs. At Peninsula Harbour, RAP partners have included EcoSuperior Environmental Programs, Marathon Pulp Inc., the Ojibways of the Pic River First Nation, the Town of Marathon, a former public advisory committee and a community liaison committee.

In 1991, the RAP partners released a report that identified the causes and extent of environmental problems in the area. The Stage 1 Remedial Action Plan Report identified five environmental challenges:

• negative impacts on sediment-dwelling organisms
• negative impacts to fish and wildlife populations
• loss of fish and wildlife habitat
• restrictions on fish and wildlife consumption
• restrictions on dredging activities.

The first line of action in dealing with most environmental problems is to control the source of pollution. In 1993, regulations came into effect to control pollution in Ontario’s lakes and rivers. These regulations, combined with Canada’s pulp and paper effluent regulations in the mid-90s, prevent companies from discharging lethal contaminants into waterways.

The pulp and paper mill at Peninsula Harbour responded by upgrading its wastewater treatment system. The result was a significant drop in the level of contaminants in the mill’s wastewater.

Next Steps
The plan is to cover the most contaminated sediment, an area of 25.6 hectares, with a 15 to 20 centimetre cap of clean sand. Work will begin in the spring of 2012 and is expected to be completed by the fall.

Once the sediment capping is complete, the RAP partners will consult with the community to decide if Peninsula Harbour can be delisted.