RUI: Photochemical Degradation, Soil Sorption, and Environmental Fate of Pharmaceutically Active Compounds in Simulated and Natural Water Samples

College Of Charleston, Charleston SC

Investigators

Abstract

1236266 Cory At this time, the environmental fate of pharmaceutically active compounds (PhACs) is largely unknown. Trace levels of these compounds are often discharged into the environment following wastewater treatment. Once they enter the environment the removal processes include solar photodegradation and sorption to soils and sediments. The objectives of this research project, which will study ten PhACs with different chemical properties, are (1) to identify the major transformation products of photodegradation for each PhAC, especially those products whose chemical structures suggest potential for environmental persistence and/or ecotoxicity; (2) to study the environmental fate of not only the parent pharmaceutical but also the products of photochemical and soil degradation; and (3) to investigate the rates of direct and indirect photodegradation in order to determine the primary route of photochemical degradation for each PhAC. To achieve the project?s objectives, the following methodologies and analyses will be employed: (1) exposure of PhAC-spiked water samples to simulated sunlight and soil samples, (2) chemical extraction techniques including ultrasonic- and microwave solvent-assisted extractions, (3) analytical techniques including high performance liquid chromatography (HPLC) and liquid chromatography with mass spectrometric detection (LC-MS), and (4) software for data analysis including chemical modeling and geochemical computer codes. The expected outcome is a more complete picture of the fate and persistence of each compound in the environment. This multidisciplinary study brings together researchers from the fields of environmental engineering, environmental geosciences, and pharmaceutical and analytical chemistry and will involve the direct participation of eighteen undergraduate researchers. The release of pharmaceutically active compounds (PhACs) into the environment is a problem of global concern. PhACs, which include drugs, personal care products and their metabolites, enter natural water systems after passing through wastewater treatment plants that have proven inefficient at removing many of these compounds. From there they travel and/or transform in the environment; the processes of natural dilution, transformation, or removal of the PhAC are a function of its chemical and physical properties. A 2002 USGS study found that 80% of 139 streams across 30 states contained detectable levels of one or more PhACs. While the measured concentrations of these compounds in natural waters are well below medical dosage levels, studies of the risk to the ecosystem have indicated adverse effects to both aquatic and non-aquatic organisms. The risk posed by this mixture of PhACs to children, women of childbearing age and people with compromised immune systems is not known. To date, most of the research in this area has focused largely on the environmental occurrence of PhACs. However, the environmental fate of PhACs "how they travel through the environment and transform into different molecules over time" is still largely unknown. Ultimately, results from this study could be used to assess and minimize the risk posed by these compounds to the ecosystem and human health as well as to engineer solutions for removal of these compounds more effectively during wastewater treatment.