A STUDY COMPARING THE MAJOR ION CHEMISTRY OF TWO STREAMS IN BLOOMINGTON-NORMAL ILLINOIS

The purpose of this ongoing project is to monitor the major ion chemistry is two streams to evaluate natural and anthropogenic effects on stream water chemistry through space and time. Both Sugar Creek and Little Kickapoo Creek originate in the eastern edge of Bloomington, IL near the Bloomington-Normal Airport. Sugar Creek runs west through Bloomington and Normal thereby taking the path of this creek through highly populated urban areas. The Little Kickapoo Creek, while originating in an urban area, runs to the south of the city through primarily rural areas of farmland whose major crops are corn and soybeans. These creeks flow across the same geologic unit comprised of a Wisconsinan glacial till. Field measurements of temperature, pH, conductivity, turbidity and dissolved oxygen are being collected at the site and shortly after the sample is collected it is titrated to determine the amount of bicarbonate in the sample. Stream gage data and precipitation are also being incorporated into the study. Water samples are being analyzed for bicarbonate, chloride, sulfate, nitrate, potassium, magnesium, calcium and sodium. The data collected to date demonstrate certain trends for particular ions. Chloride, sodium and potassium are all decreasing from winter to spring indicating these ion concentrations are the result of salting roads during winter weather. Nitrate is increasing from winter to spring and is probably the result of fertilizer use. Bicarbonate and sulfate fluctuate but appear to be naturally occurring and the fluctuations are most likely the result of variances in ground water discharge into the streams. Trends in magnesium and calcium cannot be determined with data collected and analyzed to date.