ST. LOUIS – The Mississippi River runs from Lake Itasca in northern Minnesota to the Gulf of Mexico, winding its way either through or along 10 states. But the Big Muddy’s watershed covers all or part of 32 states (approximately 41% of the land in the continental U.S.) and two Canadian provinces, making it the second-largest drainage basin in North America.
Farm fertilizers, microplastics, and pharmaceuticals dumped into Mississippi River waterways contaminates drinking water and not only causes toxic algae blooms in the river, but also contributes to the massive dead zone along the Gulf Coast.
Excess nutrients like nitrogen and phosphorous are carried from the Mississippi River and discharged into the northern Gulf of Mexico.
Normally, phosphates can spur growth in aquatic life, like fish, plants, and smaller organisms, which is healthy for the ecosystem. But a high concentration of phosphates will trigger excessive algae growth, choking off the oxygen supply in the water—known as eutrophication—and decimating all life in that particular area. Fish and other animals will vacate that area, but any life that cannot move or relocate dies.
The Gulf of Mexico Hypoxic Zone (or Dead Zone) is the second-largest dead zone in the world, and measures many thousands of square miles.
According to the Nature Conservancy, the National Oceanic and Atmospheric Administration (NOAA) estimates the Gulf Coast dead zone costs the seafood and tourism industries $82 million per year.
Combatting this problem requires partnership and action from the states in the Mississippi River Watershed, as well as local and regional jurisdictions that have direct access to those waterways.
On Wednesday, the Metropolitan St. Louis Sewer District (MSD) and Missouri Department of Natural Resources (DNR) announced a plan to reduce the amount of excessive nutrients into local waterways by two-thirds.
The plan was approved during Wednesday’s meeting of the Missouri Clean Water Commission in St. Louis.
“Missouri is one of 12 states working alongside federal, tribal, and university partners to address contributions to the Gulf dead zone using targeted federal funding and broad adoption of best management practices,” Ashley McCarty, chair of the Missouri Clean Water Commission, said.
MSD will soon reduce the use of phosphorous at its Bissell Point, Lemay, and Grand Glaize wastewater treatment facilities. According to the Environmental Protection Agency, public water systems use phosphates to reduce or eliminate lead contamination in the drinking water. MSD will use what it calls “new treatment technology” in place of phosphorous.
The DNR will see that the plan is carried out at farms and other wastewater facilities across Missouri.
Representatives for both MSD and the DNR said the goal is to reduce Missouri’s contribution to the dead zone in the Gulf of Mexico by 45% by 2035.