Occurrence and biodegradability of selected pharmaceuticals and personal care products

Environmental contamination by pharmaceuticals and personal care products (PPCPs) has recently gained public attention as an issue of concern. The ramification of PPCP contamination in water sources has not yet been fully resolved. An enhanced understanding of environmental occurrence, human exposure, and the associated risks is needed. This dissertation presents the results of analytical method development, occurrence and process modeling studies in sewage treatment plants, and biotransformation studies for 18 PPCPs in batch and column systems. The target PPCPs were selected from a broad spectrum of PPCP classes based on their calculated potential environmental concentrations.; A new analytical procedure was developed for simultaneous determination of 18 PPCPs using pentafluorobenzyl bromide as the derivatization agent and gas chromatography and mass spectrometry (GC/MS) for detection and quantification. This method afforded excellent reproducibility and high sensitivity (∼ low ng/L). Using our method, we investigated the occurrence and removal of these PPCPs in four different sewage treatment plants (STPs) with different treatment processes and operational characteristics (e.g., different solids residence times and different nutrient removal processes). These STPs serve four major cities within the mid-Atlantic and New England regions of the United States. The majority of the target analytes were detected in both the influent and effluent STP streams at ng/L levels, although some PPCPs (e.g., naproxen and ibuprofen) were encountered at mug/L levels.; A general fate model was developed to study the important factors that influence removal of the selected PPCPs in STPs. The modeling exercise concluded that biodegradation was the dominant removal process. Consequently, operating the STPs with longer solids residence times should increase the removal of these compounds. The biodegradability of our target PPCPs was further investigated in batch systems (with different electron acceptors, microbial inocula and concentrations) and column systems (with different operating conditions such as temperature and applied empty bed contact times) to gain insight into the biodegradation behavior and possible treatment options. Overall, the majority of the compounds investigated were biotransformed in batch systems, with aerobic conditions being the most favorable. The biological sand columns exhibited promise as a technology to remove these substances, but the effectiveness of biofiltration depended on the operational characteristics. Understanding the biodegradability and occurrence of the target PPCPs will help us identify and prioritize the risks associated with the presence of these compounds in aquatic systems.