PPCPS, bacteria, and other contaminants in karst springs and caves in southwestern Illinois

Karst waters are vulnerable to surface-borne contaminants in a variety of land use settings, including urban, residential, and agricultural. A series of studies in the Sinkhole Plain of southwestern Illinois, which is primarily row-crop agriculture but is undergoing increasing residential development, has indicated widespread contamination. Contaminants in the springs and cave streams are numerous, including nitrate, fecal bacteria, pharmaceuticals and personal care products (PPCPs), and steroidal hormones. The most commonly detected PPCPs were caffeine, triclocarban, carbamazepine, and gemfibrozil. Hormones were detected less frequently, with estrone being the most commonly detected. The source of the PPCPs and hormones is most likely discharge from septic systems and, in urban areas, leaking sewerage pipes. Fecal bacteria are detected in almost all samples, with fecal coliform concentrations commonly exceeding 100 CFU/100 mL. Fecal bacteria have been evaluated by a combination of Bacteroidales-based microbial source tracking (MST), traditional bacterial indicators, and environmental variables. Quantitative PCR with seven primer sets targeting different members of Bacteroidales was used to discriminate human and livestock fecal pollution. The results suggested that most samples were contaminated by a mixture of human and animal waste sources, with only a few samples showing pollution solely by humans or animals.