Summary of Surface-Water-Quality Assessment of the Upper Illinois River Basin Presented

Summary of Surface-Water-Quality Assessment of the Upper Illinois River Basin Presented

A surface-water-quality assessment was conducted in the upper Illinois River Basin in Illinois, Indiana, and Wisconsin from 1987 to 1991 by the U.S. Geological Survey (USGS). The U.S. Department of Interior assessment involved interpretation of available data; 4 years of intensive data collection at specific sites; and studies of selected water-quality constituents at many sites, according to a report recently released by the USGS.

Concentrations of cadmium, mercury, nickel, selenium, and zinc appeared generally to be higher in fish samples from the upper Illinois River Basin compared to other basins in Illinois. Loads of trace inorganic constituents in water were 2-13 times greater in the Chicago metropolitan area than from rural areas in the basin. Nutrient concentrations in water from the basin were higher than concentrations typically found in natural water. Dissolved oxygen concentrations exceeded State water-quality standards at 76 percent of the sampled sites during a 1988 survey. A strong relation between the quality of the fish commmunity and overall water-and sediment-quality conditions were observed.

The report titled "Surface-Water-Quality Assessment of the Upper Illinois River Basin in Illinois, Indiana, and Wisconsin-Results of Investigations Through April 1992," by Arthur R. Schmidt and Stephen F. Blanchard has been released as U.S. Geological Survey Water-Resources Investigations Report 96-4223. Copies of the report are available for inspection at the U.S. Geological Survey, 221 North Broadway Avenue, Urbana, Illinois, 61801. Paper and microfiche copies can be purchased at cost from the U.S. Geological Survey-Branch of Information Services, Box 25286, MS 517, Federal Center, Denver Colorado 80225-0046 (telephone: (303)202-4700). Orders must include check or money order payable to U.S. Department of Interior-U.S. Geological Survey and must specify report number WRIR 96-4223.