LABORATORY INVESTIGATION OF PHARMACEUTICALS IN THE SUBSURFACE ENVIRONMENT

Every day millions of Americans consume a vast array of pharmaceuticals, from common over-the-counter medications to prescription and illicit drugs. Much of the medication is absorbed and metabolized by the body, but a percentage passes through unchanged and is excreted into wastewater. This wastewater eventually finds its way back into the natural system of rivers, lakes, soils, and groundwater – all of which are sources of drinking water. As developing analytical techniques have increased the capability to detect these pharmaceuticals at low concentrations, scientists now have the tools to quantify these compounds at environmental concentrations. This research project determined the fate and transport of pharmaceuticals (methamphetamine, caffeine, and acetaminophen) in soils and groundwater. Large soil columns (12”x12”) were constructed using sand and undisturbed fine-grained sediments from DeKalb, Illinois. The columns were placed in a temperature controlled laboratory and each was injected with natural groundwater containing known concentrations of pharmaceuticals. Column effluent was analyzed using high-performance liquid chromatography (HPLC) methods to detect the pharmaceutical compounds and daughter products to determine loss due to biodegradation or sorption. In addition, the effluent was examined for changes in chemical constituents and geochemical parameters to determine if biodegradation occurred. The culmination of this research will quantify natural attenuation of the pharmaceutical compounds, by both microbial and physical sorption processes in different porous media. Results will facilitate continued research in the area and possibly influence regulations on pharmaceutical disposal, such as the recent changes proposed by the United States Environmental Protection Agency.