About the St. Louis River
The St. Louis River AOC is one of the 31 U.S. based Area of Concern (AOC) across the Great Lakes created under the 1987 Great Lakes Water Quality Agreement. Draining 3,634 square miles of watershed and encompassing a 1,020 sq. mi. area, the St. Louis River is the second largest U.S. based AOC. It crosses state boundaries, including both the states of Minnesota and Wisconsin. As the largest tributary to Lake Superior, the St. Louis River is vital to the regional economy and encompasses the Port of Duluth-Superior, an essential port for Great Lakes shipping. The AOC also includes
- The Interlake and U.S. Steel Superfund sites,
- Large boat slips,
- Important fish spawning habitat, and
- Spirit Lake—a site with spiritual significance to the Fond du Lac tribe.
However, historical industrial use of the river, before the onset of modern pollution laws, has resulted in sediments contaminated with
- mercurymercuryHeavy metal that can accumulate in the environment and is highly toxic if breathed or swallowed.,
- dioxinsdioxinsUnwanted chemical byproducts of incineration and some industrial processes that use chlorine. Dioxins can accumulate in fish and wildlife and are suspected human carcinogens.,
- PCBsPCBsA group of toxic, persistent chemicals used in transformers and capacitors. They often accumulate in sediments, fish, and wildlife and have been associated with health problems., PAHsPAHsA group of organic chemicals that includes several petroleum products and their derivatives., and
- other toxins.
Pollutants in the AOC are also due to
- historical discharges,
- superfundsuperfundThe common name for the clean-up fund created by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). It is often also used to refer to the clean-up process under CERCLA. sites,
- wastewaterwastewaterWater that has been used and contains dissolved or suspended waste materials. dischargedischargeFlow of surface water in a stream or canal or the outflow of ground water from a flowing artesian well, ditch, or spring. Can also apply to discharge of liquid effluent from a facility or to chemical emissions into the air through designated venting mechanisms. from the local sanitation facility,
- landfill sites, and
- other point-source discharges within the AOC.
EPA has continually worked with federal, state and local partners to execute remediationremediationCleanup or other methods used to remove or contain a toxic spill or hazardous materials from a Superfund site. and restoration work in the area with the ultimate goal of removing the AOC designation and revitalizing the surrounding communities.
On this page:
Beneficial Use Impairments
An interim success of remediation and restoration work is removing beneficial use impairments. Beneficial use impairments are designations given by the EPA representing different types of significant environmental degradation. As cleanup work is completed, and monitoring demonstrates sufficient environmental health improvements, BUIs can gradually be removed. This AOC has removed one BUI and has 8 more to remove. See below list. Once all BUIs are removed, the process of delisting the AOC can begin.
- Restrictions on fish and wildlife consumption
- Excessive loading of sediment and nutrients
- Degradation of fish and wildlife populations
- Beach closings
- Fish tumors or other deformities - REMOVED 2019
- Degradation of aesthetics - REMOVED 2014
- Degradation of benthos
- Restrictions on dredging activities
- Loss of fish and wildlife habitat
To delist the St. Louis River AOC, 75 sediment remediation and habitat restoration management actions have been identified and 25 have already been completed. Sediment remediation projects will remove contaminants such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals from the environment. Habitat restoration that will be most beneficial for improving plant and animal populations include actions such as invasive species control, fish passage projects, wetland restoration, and increasing habitat connectivity. To delist this AOC, a goal of restoring 50 percent of lost habitat (1,7000 acres) has been set. Not only will these projects enhance environmental productivity, but they will also add significant socioeconomic value to the surrounding communities.
Sediment Remediation Project Highlights: Minnesota Slip, Slip 3, and Slip C
Three slip sediment remediation projects (Minnesota Slip, Slip 3, and Slip C) in the Port of Duluth-Superior within the St. Louis River AOC. Through the Great Lakes Restoration Initiative (GLRI) and the EPA’s partnership with the Minnesota Pollution Control Agency, the projects remediate a total of 154,000 cubic yards of contaminated sediment by placing a 2 ft protective cap on top of sediment left in place. The projects, totaling $10 million, remove heavy metals, dioxins, PCBs, and PAHs from the environment and are a necessary step for the removal of two BUIs: The Restriction on Fish & Wildlife Consumption BUI and the Degradation of Benthos BUI.
Although these projects are vital to the health of the AOC, their location and process has also garnered unique attention. To complete the Minnesota Slip project, the SS William A. Irvin, a retired lake freighter now serving as a museum, has been temporarily relocated outside of the slip. Construction took place September through November 2018 and the freighter will return to Minnesota Slip in spring 2019. 18 acres have been restored, and the waterfront is now cleaner for both fish and humans alike.
Habitat restoration projects target areas that will be most beneficial for improving the local habitat, plant and animal populations and include actions such as invasive species control, fish passage projects, wetland restoration and increasing habitat connectivity. In order to delist this AOC, a goal of restoring 50% of lost habitat (1,7000 acres) has been set. Not only will these projects enhance environmental productivity, but they will also add significant socioeconomic value to the surrounding communities.
Habitat Restoration Project Highlights: 21st Avenue West and 40th Avenue West
Through a creative partnership among USEPA, USACE, MPCA, MNDNR, and other local agencies, annual harbor maintenance dredge material was beneficially used to restore critical aquatic habitat in the St. Louis River Area of Concern. Following an innovative three-year pilot program to determine that navigational material from the Duluth-Superior harbor was clean and safe enough to recycle back into the water, dredged material was placed over a total of 680 acres between 21st Ave. West and 40th Ave. West. Approximately 1 million cubic yards of dredge material has contributed to habitat enhancement through the creation of gradually sloped shorelines, the addition of shoals or islands, and the reduction of acreage exposed to excessive wave energy. Through this partnership and investment in historic industrial sites, both navigation and ecological function will be improved in the largest freshwater port of the Great Lakes. This project works to remove two BUIs: Restrictions on Dredging Activities and Loss of Fish and Wildlife Habitat.
The following links exit the site Exit
- City of Duluth, Minnesota
- City of Superior, Wisconsin
- Fond du Lac Tribe
- Illinois-Indiana Sea Grant
- Minnesota Department of Natural Resources
- Minnesota Sea Grant
- Minnesota Pollution Control Agency
- Wisconsin DNR: St. Louis River Area of Concern