As reports of hormones and pharmaceuticals being detected in water supplies surge, emerging contaminants have become cause for concern. Inspired by such evidence, scientists at the Prairie Research Institute (PRI) at Illinois State University recently conducted a study on the prevalence of emerging contaminants in Illinois’ groundwater. Walton R. Kelly, head of the groundwater section for PRI’s Illinois State Water Survey, discussed the study with WQP Editor-in-Chief Kate Ferguson.
Kate Ferguson: Why did PRI undertake this study?
Walton R. Kelly: Researchers at PRI have been involved in research of karst and cave systems for many years. Previous research indicated septic contamination of springs and caves, and we wanted to see if pharmaceutical and personal care products (PPCPs) were also being introduced.
Ferguson: What areas of Illinois were included in the study?
Kelly: The karst system of southwestern Illinois, specifically Monroe and St. Clair counties.
Ferguson: What contaminants were found in the groundwater sampled as part of the study?
Kelly: From previous studies, we knew these springs were contaminated with fecal bacteria and nitrogen. In this study, we detected several PPCPs, the most commonly detected being triclocarban (an antimicrobial), found in 81% of our samples, and gemfibrozil (a cardiovascular drug), found in 57% of our samples. Seven other PPCPs were detected in at least 10% of samples: trimethoprim, naproxen, carbamazepine, caffeine, sulfamethoxazole and fluoxetine.
Ferguson: How can these contaminants affect the environment? How can they affect humans?
Kelly: This research is still in its infancy, but certain PPCPs and hormones have been shown to have negative effects on aquatic biota, including fish and amphibians. The effects on humans are pretty much unknown. Concentrations tend to be very low, at sub-therapeutic doses, but mixtures of these compounds can have synergistic effects that are very hard to predict.
Ferguson: Has evidence of wildlife affected by hormones or pharmaceuticals been found in Illinois?
Kelly: I believe most of the work on wildlife effects [is] done in laboratory settings.
Ferguson: What are possible causes of the groundwater contamination in this area?
Kelly: The main source in our study is probably septic system discharge. Other studies have shown that water resources can be contaminated with PPCPs and hormones by treated sewage effluent or discharge from livestock facilities.
Ferguson: What impact could this contamination have on municipal drinking water supplies? What impact could it have on private water wells?
Kelly: This is an area of research. Much surface water in our part of the world contains some amount of treated wastewater, and if a community withdraws water from a river downstream of a wastewater discharge point, it’s likely the water will include some of these compounds, and some of them are known to persist through the wastewater treatment processes. Previous research by us and others has indicated that private wells in karst regions are vulnerable to surface contamination, and care must be taken in well construction and protecting the land above the area contributing recharge to the well.
Ferguson: Is karst terrain found in other areas of the U.S.? What makes it susceptible to contamination?
Kelly: Karst is a very common type of landform. In our paper, we cite studies that report that karst areas comprise 20% of the world’s land mass and that karst aquifers are a source of drinking water for 25% of the population. The Midwest is well known for karst regions, especially in Kentucky (Mammoth Cave), Missouri, Arkansas, Wisconsin and Indiana. Karst features such as sinkholes and underground conduits facilitate the transport of surface waters into underlying karst aquifers with little of the remediation that is characteristic of percolation through soils. Because of this rapid transport, karst aquifers are highly vulnerable to surficial contaminants from surface waters in their watersheds.
Ferguson: Are any other water quality-related studies planned or in the works?
Kelly: We’d love to continue this work. We feel we’ve only really provided a “snapshot” of what’s going on in this karst aquifer, and we’d like to do a more comprehensive study. We’re also interested in potential effects on cave biota.
