Michigan Restoration Project Removes Pollutants

Harmful to Human Health

Federal Great Lakes restoration funds helped support the removal of more than 500,000 pounds of harmful pollutants from the St. Marys River that helped make the river safer for fish and, ultimately, the people who eat those fish.


Historic pollution discharges from a tannery and a manufactured gas plant on the U.S. side of the St. Marys River contaminated a large area of the river bottom with mercury, chromium and toxic chemicals that were toxic to fish and other aquatic life. Mercury and other pollutants in the sediment accumulated in fish, posing health threats to humans and wildlife that consumed the tainted fish.

Resource Challenges Addressed

  • Toxic pollution
  • Degraded fish and wildlife habit


Barge Dredging river

Contaminated materials were dredged out, like the operation above, so fish and wildlife could return. Credit: Joseph G. Bailey Michigan Sea Grant.

Results and Accomplishments

In 2007, dredging in an area of the St. Marys River known as Tannery Bay removed 40,000 cubic yards of contaminated sediment that contained 500,000 pounds of chromium and 25 pounds of mercury. The contaminated sediment that was removed would have covered an area the size of a football field to a height of 24 feet. In 2010, crews dredged another 26,000 cubic yards of contaminated sediment in an area of the river near the MCM Marine Facility. That area was contaminated in the early 1900s by a manufactured gas plant.