Nutrients, such as nitrogen and phosphorus, come mainly from agricultural runoff and farm fertilizers but also from municipal sewage, animal feedlots, and runoff from golf courses and lawns. Of these, row crops accounted for 7,051 of the polluted stream miles while animal feedlots accounted for only 124 miles.
Agricultural fertilizers are the main source of nutrient pollution in downstate Illinois.
While nutrient pollution is a serious issue in Illinois, it also causes problems far downstream. Excess nutrients in the Dead Zone allow algae and phytoplankton to thrive, taking oxygen out of the water. The source of the nutrients is agricultural fertilizers in the Midwest. A federal task force, made up of representatives of federal agencies and states along the Mississippi River has been studying the problem in the Gulf and suggesting solutions. The task force has examined six detailed scientific studies and has proposed a draft action plan to solve the problems in the Gulf.