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 – each of which is a possible source of drinking water. Developing analytical techniques have increased the capability to detect these pharmaceuticals at low environmental concentrations. This research determined the biodegradation and sorption of methamphetamine, acetaminophen, and caffeine in large scale columns (12”x12”) made of 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 influent and effluent were analyzed using High Performance Liquid Chromatography/Mass Spectrometry (HPLC/MS) to detect the pharmaceutical compounds, and geochemical parameters were monitored to determine if biodegradation occurred.

Biodegradation of caffeine, acetaminophen, and methamphetamine was observed in all columns. The highest amount removed (approximately 90%) occurred in the undisturbed column injected with methamphetamine, compared with little detected reduction in the column of sand. When the suite of drugs was injected, loss of methamphetamine was less than when methamphetamine was injected alone. Elevated levels of iron and manganese were observed in the effluent from the undisturbed column after the mix of drugs was injected. This is evidence of an anaerobic environment where microbes utilized these metals as alternate electron acceptors. When compared to the KCl tracer, methamphetamine is sorbed more than caffeine, with acetaminophen having the least sorption. The subsurface sediments exhibit the ability to remove a substantial amount of the injected pharmaceuticals; however, complete removal was not achieved. The sand column did not show sizeable reductions in the injected pharmaceuticals, and demonstrates a concern for water quality in the environment if pharmaceuticals were to contaminate a sandy aquifer.