Progress at Lake Superior Contaminated Sites
Posted on: August 7, 2019
Duluth-Superior Harbour and the St. Louis River estuary comprise the St. Louis River Area of Concern. Significant progress has been made at several contaminated sites in the harbour and estuary.

Several specific locations in the waters of Lake Superior were contaminated by the industrial legacy of decades past. Considerable progress has been made when it comes to cleanup but significant challenges remain.

In Canada, these locations include:

• The harbour at the Town of Marathon, called Peninsula Harbour

• Jackfish Bay, east of Terrace Bay, along with Blackbird Creek which flows into it

• Thunder Bay

On the U.S. side of Superior, contaminated sites exist at:

• Duluth – Superior Harbour including the St. Louis River estuary

• Torch Lake (on Michigan’s Upper Peninsular)

All of the above Canadian and U.S. locations have been designated as Great Lakes “Areas of Concern.” A cleanup for mercury contamination at Deer Lake, Michigan has been completed and, as a result, this area has been removed from the list of Areas of Concern. The legacy of pulp and paper on both sides of the border and also mining, specifically refining on the U.S. side, are associated with these contaminated sites. Today, much more stringent environmental regulations are in effect.

Buffalo Reef, near Gay, Michigan on the Upper Peninsula, is not an Area of Concern but is being encroached upon by stamp sands from metal refining. The reef is an important area of fish habitat and plans are underway to stop the encroachment.


Peninsula Harbour Cleanup Carried Out in 2012


Thin-layer cap material
A sample of material deposited in Peninsula Harbour for construction of the thin-layer cap remediation project.

Mercury in harbour sediment was the major concern at Peninsula Harbour, but this issue was addressed in 2012 when Environment and Climate Change Canada (ECCC), the provincial Ministry of the Environment, Conservation and Parks (MOECP) and private industry carried out a $7 million cleanup. A layer of sand, along with more coarse material for “high energy” portions of the harbour, was laid down on the harbour floor over the area of highest contamination. A primary aim of the project was to allow benthic organisms to recolonize this area. Benthic organisms are small, sometimes microscopic organisms, which inhabit sediment. Environmental monitoring is ongoing to quantify recolonization and other parameters.


Creosote Contamination Cleaned Up in 2003


In Thunder Bay, a $25 million  project was completed in 2003 to clean up creosote contamination around the former Northern Wood preservers property. This industrial facility was located in the central portion of the harbour. The project involved sealing off the area of highest contamination with a berm, dredging out the contaminated sediment and then back filling the area with clean fill. A large area of habitat was also created at this former industrial site. In effect, shallow embayments and wetlands were created for many species of fish, birds and other wildlife. The project was carried out by ECCC, MOECP and private industry.

While there has been considerable progress to address contamination in Lake Superior, significant challenges remain. Jackfish Bay is a deep indentation in Superior’s coastline. Blackbird Creek, into which the mill at Terrace Bay has discharged wastewater for decades, meanders several miles before flowing into the bay. Legacy contamination in both creek and bay sediment includes dioxins and other chemicals. 


Jackfish Bay Presents Complex Issues


The Jackfish Bay/Blackbird Creek situation is complex. Even local residents have conceded that cleaning up a creek which is miles in length would be extremely difficult, to say nothing of prohibitively expensive. Environmental monitoring is considering sedimentation rates and whether such sedimentation may, eventually, bring about gradual environmental recovery. As such, in 2012, Jackfish Bay, including Blackbird Creek, were deemed an “Area of Concern in Recovery.” This designation refers to an area that was originally identified as an area of concern where, based on community and government consensus, all scientifically feasible and economically reasonable actions have been implemented and additional time is required for the environment to recover.


Thunder Bay’s North Harbour – Can Cleanup Costs be Lowered?


Aerial view of the North Harbour area with the mill in operation (circa 1980).

In Thunder Bay, the northern portion of the harbour, adjacent to the mouth of the Current River and within the break wall, contains some 400,000 cubic meters of pulpy material contaminated with mercury and other chemicals. This material is suspended within Superior’s waters. Contaminated material is 3 or more meters thick in some areas and covers 26 hectares of the harbour. The site is near a former paper mill. 

The pulpy, or porridge-like, nature of this material, along with its very large volume, means this location may be both difficult and expensive to clean up. Currently,  considerable effort is being expended by a steering committee comprised of government agencies and local stakeholders to identify low-cost cleanup options. Such options include the following:

• transport across the harbour for disposal at an existing facility designed to contain material from navigational dredging 

• disposal at existing effluent lagoons on the nearby former nearby mill.

Cleanup options will be presented to the public in the coming months.


U. S. Side – Progress at Duluth


Considerable contamination exists at multiple locations within Duluth-Superior Harbour including the St. Louis River Estuary; also at Torch Lake in Michigan. In the case of Duluth-Superior, considerable cleanup progress has been made at several locations and work is proceeding according to a very ambitious master plan. 

We live in an era with multiple environmental issues coming to the fore. This includes everything from microplastics to climate change. It is important to remember that cleanup of the above mentioned locations is fundamental to the health of Lake Superior. Hopefully, the gradual success being achieved on both sides of Superior will lead to resolution at Superior’s remaining contaminated sites. Hopefully, the extremely expensive costs of cleanup will be borne in mind in order that prevention prevails, before more cleanups are required. 


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