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Tracing the Sources of Macrolide Antibiotics and Illicit Drugs into the Lower Colorado River Basin
Citation:
JONES-LEPP, T. L., C. A. Sanchez, AND D. Wilson. Tracing the Sources of Macrolide Antibiotics and Illicit Drugs into the Lower Colorado River Basin. Presented at 42nd American Chemical Society Western Regional Meeting, Las Vegas, NV, September 23 - 27, 2008.
Impact/Purpose:
Presentation
Description:
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 macrolide antibiotics (azithromycin, roxithromycin, clarithromycin, clindamycin) and illicit drugs (methamphetamine, Ecstasy) in surface waters of the lower Colorado River region. Waste stream tributaries and receiving surface waters at selected locations along the Colorado River in Nevada, Utah, Arizona, and California were sampled. These water samples were prepared for analysis using an automated extractor (AutoTrace, Caliper Life Sciences) with Oasis MCX cartridges (Waters Corp.), subsequently extracted with 5-mL of 80:20:1 methyl tertbutyl ether/methanol/acetic acid, and 5 mL 99:1 methanol/acetic acid, and reduced to 0.5 mL using an automated evaporator (TurboVap-Zymark, Caliper Life Sciences). Data were collected with a Varian 500MS ion trap mass spectrometer by performing mass analyses of LC eluents. One or more macrolidic antibiotics and /or illicit drugs were found in urban waste streams at concentrations frequently exceeding 100 ng/L. However, amounts found in the main surface water channels diverted for urban use and irrigation, including the Colorado River, were always below 10 ng/L and most frequently below detection.