The photos speak for themselves: Thunder Bay’s North Harbour faces a serious issue. Take a look at the summary, documents, and timeline related to mercury contamination below.

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Overview of Issue:

In 1985, the International Joint Commission identified forty-three different Areas of Concern (AOCs) across the Great Lakes where the environmental quality had deteriorated to the point that the beneficial use of these aquatic areas was being impacted.  Thunder Bay was identified as one of these areas of concern for a number of different reasons including the contaminated sediment in the Thunder Bay north harbour from historic effluent discharge of a former paper mill.


The site in question is contaminated about 350,000 cubic meters of organic sediment deposited over 90 years of mill operations. This sediment is subsequently contaminated with mercury in concentrations that range from 2 to 11 ppm at the surface of the sediment to 21 ppm at depth.  The sediment layer itself is composed of a relatively fibrous material with thicknesses ranging from 40 to 380 centimeters and covering an area of about 22 hectares.

Mapping Tool

In order to remediate these areas of concern the remedial action plan (RAP) was implemented which sought public input on the contamination and remediation efforts through their public advisory committee (PAC).  Over the years the PAC has received a variety of information on the contaminated sediment and the different options available to remediate it.  Links to these reports and presentations are presented below.

Links to Key Documents:

March 2006 – North/South Consulting – Report
August 2010 – AMEC Phase I Feasibility Study
January 2011 AMEC Phase II Feasibility Study
April 2011 – Environment Canada – Geometry and Estimated Volume Tech. Report
June 2011Anchor QEA Feasibility Study Phase II – Peer Review
December 2012
Northern Bioscience – Fish Community and Habitat Synthesis
June 2013Franz Environmental – Report
March 2014 – Cole Engineering –  Options Evaluation Summary
August 2014Cole Engineering Final Report & Final Report Figures

June 2022 – Thunder Bay North Harbour Sediment Management Project Update

Over the years the public has had the opportunity to review and comment on the above reports.  The PAC has compiled a selection of these responses and links to them are also presented below.


Public Questions and Comments to date:

April 2010 – North Harbour Steering Committee (NHSC) Response to PAC Questions
October 2010 – Questions and Answers for the NHSC from September PAC Meeting

November 2011
– Answers to Questions generated at October PAC Meeting
December 2011 – Letter from the PAC to the NHSC

February 2012
– PAC Meeting Minutes
December 2012 – PAC Meeting Minutes

February 2013 – Answers to Questions generated at February PAC Meeting
April 2013 – Questions to Franz Environmental generated at April PAC Meeting
September 2013 – Updated North Harbour from Jamie Saunders for PAC Meeting
November 2013 – PAC Meeting Minutes

March 2014
– PAC Questions and Answers to Cole Engineering Presentation
March 2014 –Public’s Questions and Answers to Cole Engineering Presentation

March 2016 – Letter sent to federal and provincial MPPs, Chronicle Journal, Port Authority


Moving from Phase I to Phase II of the Thunder Bay North Harbour Sediment Remediation Project.

After reviewing the Thunder Bay North Harbour Working Group’s recommendation report, TBNH Senior Management Committee has agreed to accept the recommendation of SMO A (SMO A-managing the contaminated sediment through dredging and disposal at an on-site confined disposal facility).

There are three phases to the TBNH Sediment Remediation Project:

  • Phase I – selection of the preferred Sediment Management Option (SMO) – completed
  • Phase II – complete engineering design – in progress
  • Phase III – implementation and monitoring 

To this end, work is underway to prepare the tender document for the engineering design of SMO A.

With SMO A identified for the project, the Committee will re-convene to plan for the engineering design for the project. This Phase will include four main tasks:

· Task 1: Completion of tender document for engineering design of SMO A

· Task 2: Award contract for engineering design

· Task 3: Prepare engineering design, cost estimate, permits and approvals

· Task 4: Prepare specification and drawings for project implementation

The Committee is currently engaged with Task 1 above and will plan for the remaining tasks. 

Here you can find more documents related to the Thunder Bay North Harbour Sediment Management Project: 

Thunder Bay North Harbour Sediment Management Project Update – the full version of the memorandum that documents the work completed by the Committee for Phase I (selection of the preferred SMO)

Canada-Ontario Agreement (COA) on Great Lakes Water Quality and Ecosystem Health 2021 – sets out specific actions each government will take to protect and restore the Great Lakes

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