Where does water pollution come from?
Literally thousands of pollutants find their way into Illinois rivers. These chemical and biological pollutants include pesticides, fertilizers, nutrients, metals, organochlorines, pharmaceuticals, pathogens, and sediment. Pollutants vary greatly in their toxicity and physiological and ecological effects. Environmental damage that can result from water pollution ranges from alteration of sub-cellular functions in aquatic organisms to changes in large-scale ecosystem processes. Sources of pollution are divided into the broad categories of “point source” and “non-point source.”
Point source
Point sources are defined by the Clean Water Act as “any discernible, confined and discrete conveyance” of pollutants to a river. Conveyances include pipes, ditches, channels, tunnels, and conduits. Point sources are regulated by the Clean Water Act, and must have a National Pollutant Discharge Elimination System (NPDES) permit to discharge into rivers. These permits limit the allowable amount of pollutants in the discharge. Some examples of point sources are:
- Sewage treatment plants
- Factories
- Urban storm drains
- Confined animal feeding operations (CAFOs)
- Floating vessels
- Construction sites
Non-point source
Non-point source pollution is polluted runoff that results from rain or melting snow carrying pollutants from land to water. Non-point source pollution is the largest contributor to water degradation in the state. Non-point sources are not regulated in the same way as point sources, but state and federal programs exist to reduce the potential for runoff to contaminate rivers. Non-point source pollution results from land disturbance activities such as:
- Agriculture
- Mining
- Forestry
- Urban development
Pollution in Illinois Rivers
The Illinois River stretches for 273 miles and drains over 30,000 square miles of land. Its basin includes 46 percent of Illinois’ agricultural land and 95 percent of its urban population.
One of the greatest threats to streams in several areas of Illinois is poorly planned urban and suburban development. As natural and agricultural lands are converted to roads, parking lots, manicured lawns, and strip malls, streams suffer many changes. Many waters become polluted by new sewage discharges, stormwater that runs off construction sites, lawn care chemicals that wash into streams, fluids oozing from automobiles, and so on.
- Chicago River in downtown Chicago
The large population in the Chicago area causes billions of gallons of treated sewage to be discharged to the Des Plaines, Fox, and other tributaries of the Illinois. Rapid development in Chicago’s sprawling suburbs is causing loss of riparian habitat and degradation of high quality streams. Agricultural lands which dominate the majority of the watershed contribute sediment and high levels of agricultural chemicals. The basin’s streams also continue to be impacted by “legacy” problems such as sediments contaminated by metals and toxic chemicals, a result of past environmental abuses.
Nutrients are among the most important water quality issues impacting the Mississippi River basin as a whole. Studies estimate that, whereas the Illinois contributes only 7 percent of the Mississippi’s flow into the Gulf of Mexico, it contributes 15 percent of the total nitrogen reaching the Gulf. These findings are corroborated by a federal task force assembled to study the Gulf Dead Zone.
While most of this nitrogen comes from agriculture and other land use activities, the Upper Illinois River is one of only two areas in the entire Mississippi River basin where municipal pollution is a major source of nutrients.
Prairie Rivers Network is fighting to keep pollution out of our rivers and the water we drink by advocating for the effective and full implementation of the Clean Water Act, including strengthen individual pollution permits and overall policies and water quality standards; aggressive grassroots advocacy; and application of the latest scientific findings.