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The objective of this study is to evaluate the presence of selected pharmaceuticals (macrolidic antibiotics and pseudoephedrine) and illicit drugs (methamphetamine, Ecstasy) in surface waters in the southwestern U.S. and evaluate the potential for food chain transfer when pharmaceutical containing waters are used for irrigation.
Non-Technical Summary: A number of pharmaceuticals have been detected in surface waters across the United States. Antibiotics present in the environment can produce resistance in microorganisms which could potentially have adverse effects on human health. In addition, while the ecotoxicological significance of trace levels of illicit drugs in surface water are not well understood, their presence cannot be dismissed outright because of their potential to adversely affect biota during prolonged exposure. The objective of this study was to evaluate the presence of selected pharmaceuticals (macrolidic antibiotics and pseudoephedrine) and illicit drugs (methamphetamine, Ecstasy) in surface waters of the Colorado River basin and evaluate their potential uptake in food crops irrigated with this water. <P> Approach: Samples will be collected spatially and temporally from waste stream tributaries and receiving surface waters in the southwestern U.S. Studies will include greenhouse experiments where selected food crops will be irrigated with water spiked with macrolide antibiotics and field experiments where selected field crops will be irrigated with treated waste water effluent containing one or more macrolide antibiotics, pseudoephedrine, and methamphetamine. Water samples will be prepared for analysis using an automated extractor (AutoTrace, Caliper Life Sciences) with Oasis MCX cartridges (Waters Corp.), subsequently extracted with 5-mLs of 80:20:1 methyl tertbutyl ether/methanol/acetic acid, and 5 mLs 99:1 methanol/acetic acid, and reduced to 0.5 mL using an automated evaporator (TurboVap-Zymark, Caliper Life Sciences). Plant materials will be extracted using a modified pressurized liquid extraction (PLE) technique, followed by a rigorous hexane clean-up. Water extracts and plant PLE extracts will be analyzed by liquid chromatography-electrospray-ion trap mass spectrometry (LC-ESI-ITMS/MS) in the positive ionization collision induced mode (CID) for greater specificity.