Groundwater quality of springs and wells of the Sinkhole Plain in southwestern Illinois: Determination of the dominant sources of nitrate
Nearly half of the residents living in the karst regions of St. Clair, Monroe, and Randolph Counties in southwestern Illinois use the shallow karst aquifer of Illinois sinkhole plain as their source for potable water. This study was undertaken to better understand the sources and pathways of contaminants in the areas wells and streams. The investigation used chemical and isotope analyses to characterize the quality and general geochemistry of the groundwater in the karst aquifer of the sinkhole plain region and to determine the dominant sources of anomalously large concentrations of nitrate in the regions groundwater.