PDF fact sheet in the series "Monitoring the State of the St. Lawrence River" on the St. Lawrence Plan web site.
Historical activities like waste dumping, manufacturing, and dredging or filling in the river left behind contamination and destroyed habitats. The research team was headed by Christina Remucal, University of Wisconsin-Madison, and Kristine Wammer, University of St. Thomas.They focused on four pollutants: the insect repellant DEET, the cholesterol-inhibitor atorvastatin, the antidepressant venlafaxine, and the anti-epileptic medicine carbamazepine.They chose to study the St. Louis River because of the variety of organic matter along its course. Another source of pollution was smoke. Situated between the urban areas of Duluth, Minnesota, and Superior, Wisconsin it is home to the country’s busiest and largest bulk inland port. From upstream to downstream, these included Sand Creek, Meadowlands, East Detroit, Munger Landing, the Western Lake Superior Sanitary District treatment plant, the Blatnik Bridge and Wisconsin Point.In the lab, the researchers added a pollutant to a water sample, then exposed it to light. The radicals have unpaired electrons that want to pair up. Remucal explains, “The headwaters are full of wetlands and all the organic carbon is really terrestrial – coming straight from plants. Credit Pine River Superfund Citizen's Task Force. Today, the St. Louis River estuary is listed as a U.S. Environmental Protection Agency NOAA has identified the following objectives for the St. Louis River estuary habitat focus area:Details about the objectives and specific actions NOAA is implementing can be found in the Habitat Focus Area Implementation Plan.Because the St. Louis River is a shared (regional) tributary to Lake Superior, NOAA works closely with many partner agencies (federal, state, local, tribal, and others) in St. Louis River estuary as part of a collaborative watershed approach to conservation and restoration. The Spirit Lake, Former U.S. Steel Duluth Works site is located in Duluth, Minn., about 10 miles upstream of the mouth of the St. Louis River where it enters Lake Superior. It's free and you can receive an electronic or print version.Funding provided by the National Sea Grant College Program, National Oceanic & Atmospheric Administration and the State of Wisconsin.Tea and sunlight: Exploring how nature breaks down pollution in the St. Louis River What is now a 54-acre vacant lot in the middle of St. Louis, once stood the Michigan Chemical and Velsicol Chemical plants that produced various chemical compounds and products from 1936 to 1978. Listen to the podcast . Submitted photo.Water that forms the beginnings of the St. Louis River in northern Minnesota percolates through moldering plants in remote wetlands and bogs. Many years of toxic discharges have led to high concentrations of contaminants in the sediments, water column, plants, and wildlife.
Water samples from the St. Louis River show differing levels and types of dissolved organic matter, from near the headwaters (on the right) to Lake Superior (on the left). Once you get out into Lake Superior, the quality of the organic matter is quite different.”Energy from sunlight can also break down the pollutants on its own in a process called direct photolysis, or it can interact with the dissolved organic matter to break down the pollutants in a process called indirect photolysis. The town had to shut off their wells and switch to a new water supply. “Besides the St. Louis River, we’re going to work in lakes in northern Wisconsin, down here in Madison, also some agriculturally impacted sites in Minnesota and more urban sites around Minneapolis.”Sign up for our quarterly newsletter featuring Wisconsin Sea Grant research, education and outreach. The plant was later buried - on site - buildings, contamination and all - after an agreement with the EPA and the State of Michigan.