Peninsula Harbour

About the Peninsula Harbour AOC

Peninsula Harbour is adjacent to the town of Marathon, Ontario, approximately 290 kilometres east of Thunder Bay on the north shore of Lake Superior. The AOC includes the town of Marathon and is comprised of two regions: Peninsula Harbour to the north of Marathon and an area of Lake Superior extending 4 kilometres out from Pebble Beach.

Peninsula Harbour was designated as an Area of Concern (AOC) in 1987 due to the effects of a pulp and paper mill (which closed in 2009) and the associated chlor-alkali plant in Jellico Cove, municipal wastewater discharge, and a history of log booming operations. Contaminants such as mercury and PCBs were dumped into the harbour, which proceeded to contaminate fish and sediment.

At this time, 5 of the Great Lakes Water Quality Agreement’s 14 Beneficial Use Indicators of ecological quality were deemed as impaired, and 1 indicator required further assessment.

In 1991, Marathon community members came together to form a Public Advisory Committee, which assisted federal and provincial agencies in developing the first stage of the RAP for Peninsula Harbour (Stage 1 Report, 1991). This plan was developed to identify environmental problems and determine sources of pollution in the AOC.

Concerns

Chemicals of concern included:

  • Polychlorinated biphenyls (PCBs)
  • Mercury

Concerns relating to the contamination:

  • Bacterial contamination
  • Aesthetic impairment
  • Degraded fish and benthic communities
  • High levels of toxic contamination, i.e. mercury and  polychlorinated biphenyls (PCBs) in fish and bottom sediments

Current Status & BUIs

The current state of the Peninsula Harbour AOC has greatly improved since it was first listed as an AOC in 1987. There were 14 environmental issues, also known as Beneficial Use Impairments (BUIs), which were considered in each Area of Concern. BUIs are changes in chemical, physical and/or or biological properties that have impaired ecosystem benefits, or uses. A status summary for the Peninsula Harbour Area of Concern follows:

To view a table that lists the original problems identified in the 1991 Stage 1 RAP report, their status in the subsequent Stage 2 RAP report (2012), and their current status as of 2022, click here.

1

BUI is currently identified as impaired.

Restrictions on fish consumption

The remaining

13

BUIs have all been identified as “Not Impaired”.

In 2022, we proudly released The Peninsula Harbour Area of Concern Status Report 2022, which shows a great example of collaborative efforts made by conservation authorities, municipalities, First Nation communities, Métis communities, environmental groups, industry and the public to develop and successfully implement the Remedial Action Plan (RAP) for the Peninsula Harbour Area of Concern (AOC). The Report summarizes the remedial and monitoring activities undertaken over the history of the Peninsula Harbour Remedial Action Plan, and to present an update on the status of beneficial use impairments (BUIs) within the Area of Concern. 

The Status Report discusses what study findings are indicating about the current state of the environment, and provides evidence that supports the recent re-designations to Not Impaired status of three of the four remaining beneficial use impairments (BUIs) in the AOC: Degradation of Fish and Wildlife Populations, Loss of Fish and Wildlife Habitat and Degradation of Benthos.

Work Completed to Date

Progress Highlights

Below, you’ll find some major milestones for the Peninsula Harbour Area of Concern along the way:

1978
Peninsula Harbour is identified as an Area of Concern in the Great Lakes Water Quality Agreement (GLWQA).
1991
The Stage 1 Remedial Action Plan (RAP) Report

The Stage 1 Report for the Peninsula Harbour AOC identified 6 beneficial uses as “impaired”, 11 as “not impaired” and 2 as “requiring further assessment” (see the table Summary of Peninsula Harbour BUIs: 1991-2010 above).

Environment Canada and the Ontario Ministry of the Environment have been working towards the goals identified in the Peninsula Harbour RAP. This has involved characterizing the extent of environmental risk from mercury and polychlorinated biphenyl (PCB) contamination of harbour sediments, as well as monitoring and assessing trends in fish and wildlife health in the AOC.

1995
Federal and Provincial Municipal Industrial Strategy for Abatement (MISA) regulations significantly improve effluent quality at the Marathon mill.
2008
The Environmental Risk Assessment for Peninsula Harbour

This was prepared and released by Environ Inc. and outlines risks associated with contaminated harbour sediment. It includes both an ecological risk assessment (ERA) focused on risks posed to fish and wildlife and a screening level human health risk assessment (HHRA) focused on risks posed to people who eat fish caught in Peninsula Harbour.

Following a series of meetings with stakeholders in Marathon and Pic River, thin-layer capping is selected as the most suitable choice for management of contaminated harbour sediment. 

2012
The Stage 2 Remedial Action Plan (RAP) Report

The Stage 2 Report for the Peninsula Harbour AOC outlines water use goals and actions to achieve these goals, as well as the remedial strategies for ecosystem restoration. The report identified 2 beneficial uses that remained “impaired” (Restrictions on Fish Consumption and the Degradation of Benthos) and 2 requiring further assessment (Degradation of Fish and Wildlife Populations and the Loss of Fish and Wildlife Habitat).

2012
Sediment Remediation Project

A major Sediment Remediation Project in Peninsula Harbour at Marathon, ON, was co-funded by the Governments of Canada and Ontario. A thin-layer cap of 15-20 centimetres of clean sand is placed on top of the most contaminated sediment in Jellicoe Cove (Cost: $ 7,300.000. Former pulp mill owners contributed $3.0M, Environment Canada – $2.7M, Province of Ontario – $1.6M).

2017
Jellicoe Cove Thin-Layer Cap Long-Term Monitoring Assessment

The Jellicoe Cove Thin-Layer Cap Long-Term Monitoring Assessment was completed by Ontario Ministry of the Environment, Conservation, and Parks. This survey demonstrated that the thin-layer sediment cap is effective and met the goals and objectives of the remedial effort.

2022
The Peninsula Harbour Area of Concern Status Report

The Peninsula Harbour Area of Concern Status Report summarizes the remedial and monitoring activities undertaken over the history of the Peninsula Harbour Remedial Action Plan, and presents an update on the status of beneficial use impairments (BUIs) within the Area of Concern. The Status Report provides evidence that supports the recent re-designations to Not Impaired status of three of the four remaining beneficial use impairments (BUIs) in the AOC: Degradation of Fish and Wildlife Populations, Loss of Fish and Wildlife Habitat and Degradation of Benthos.

To download an image of this timeline, click here.

Peninsula Harbour Sediment Remediation Project

Elevated levels of mercury and PCBs have accumulated in the Jellicoe Cove portion of Peninsula Harbour adjacent to a former pulp mill. The source of harbour mercury was a chlor-alkali plant, which, at one time, operated beside the pulp mill. To create a clean habitat for plants and animals, and to accelerate natural recovery, Environment Canada and the Ontario Ministry of the Environment put in place a project to cap this contaminated sediment with clean sand.

The project was completed during the summer of 2012. The integrity of the cap and “re-colonization” of the area by bottom-dwelling organisms, including plants, will be monitored for the next 20 years. The capping project is the last major action required to address environmental concerns in Peninsula Harbour.

Click here to find additional photos of the the first post-cap long-term monitoring (LTM) survey (2017) demonstrated that the thin-layer sediment cap is effective and met the goals and objectives of the remedial effort.

WATCH: Overview of Peninsula Harbour Sediment Capping Project (Environment Canada)

The Use of Thin-Layer Cap to Manage Hg and PCB Contaminated Sediments in Jellicoe Cove, Peninsula Harbour, Ontario, Canada. November 20, 2012. Technical presentation by Kay TIm et al. from the Environmental Canada Sediment Remediation Unit on the thin-layer capping project in Jellicoe Cove, Peninsula Harbour. The presentation covers the sediment studies, risk assessment, management options, cap design, implementation, and long-term monitoring of the project.

Peninsula Harbour Area of Concern Thin-Layer Cap Long-Term Monitoring. 2021. Created by Tara George, Ministry of the Environment, Conservation and Parks, Great Lakes Unit.

What's Next

In the coming 1 to 2 years, the RAP will work towards completing a fish consumption assessment.

Documents

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