Why It Is Important
More than 18 million people depend on the Mississippi River for drinking water. Like many of the world’s largest rivers, the Mississippi starts as a clear-water stream in its headwaters, but picks up loads of sediment and becomes a murky, brown river as it flows downstream, earning the river one of its many nicknames: the Big Muddy. While some sedimentation is natural in a big watershed, the high levels in the Mississippi are largely the result of the vast amount of agriculture in the region. Rains and melting snows carry loose topsoil along with pesticides, fertilizers and manure, into the Mississippi River watershed.
Industrial wastes were routinely dumped into the river and its tributaries before modern pollution laws were enacted in the 1970s. But even after the passing of the Clean Water Act, enforcement has been problematic and stretches of the Mississippi River are heavily polluted by the wastewater from oil refineries, chemical production and other industries.
Sewage is another large-scale threat to the Mississippi River’s water quality. According to the Clean Water Act, America’s waters are supposed to be "fishable and swimmable," but aging sewage systems, rapid growth of suburban development, and increased stormwater from a changing climate all contribute to the failed capture of pollutants before they reach the River. Many cities along the river have combined sewer systems, which treat both sanitary sewage and stormwater. Following heavy rains, these systems can be flooded, flushing untreated overflow into the River. This means raw sewage, bacteria and other pathogens flow directly into the River, along with debris, oil and grease from city streets, road salt and other pollutants.
Based on a recent national EPA study of streams and small rivers, Dr. Eugene Turner of Louisiana State University concluded that about half of the streams and rivers in the Mississippi River watershed are in poor condition, unsafe for swimming, drinking or recreational contact.1
While communities that depend on the Mississippi River for drinking water treat and purify the water for human uses, nothing is done for the fish and wildlife that also depend on the River. The costs of cleaning up excessively polluted water are usually incurred by local communities and taxpayers.
What You Can Do
To safeguard the River, and the people and wildlife that depend upon its waters, you can work for stronger enforcement of clean water laws, support projects to modernize sewage treatment systems, and encourage agricultural practices that reduce soil erosion and chemical use. At home, you can take simple steps like conserving water, which helps reduce the amount of water handled by overtaxed sewage systems, and avoiding lawn and garden chemicals, which can reduce chemical and nutrient loads in the river. For more information on what you can do, go to the River Action Items section.
1 USEPA Wadeable Streams Assessment, A Collaborative Survey of the Nations Streams. December 2006. www.epa.gov/owow/streamsurvey