No abstract

We present an isotopic-dilution direct injection reversed-phase liquid chromatography-tandem mass spectrometry method for the simultaneous determination of 23 drugs of abuse, drug metabolites, and human-use markers in municipal wastewater. The method places particular emphasis on cocaine; it includes 11 of its metabolites to facilitate assessment of routes of administration and to enhance the accuracy of estimates of cocaine consumption. Four opioids (6-acetylmorphine, morphine, hydrocodone, and oxycodone) are also included, along with five phenylamine drugs (amphetamine, methamphetamine, 3,4-methylenedioxy-methamphetamine, methylbenzodioxolyl-butanamine, and 3,4-methylenedioxy-N-ethylamphetamine) and two human-use markers (cotinine and creatinine). The method is sufficiently sensitive to directly quantify (without preconcentration) 18 analytes in wastewater at concentrations less than 50 ng/L. We also present a modified version of this method that incorporates solid-phase extraction to further enhance sensitivity. The method includes a confirmatory LC separation (selected by evaluating 13 unique chromatographic phases) that has been evaluated using National Institute of Standards and Technology Standard Reference Material 1511 Multi-Drugs of Abuse in Freeze-Dried Urine. Seven analytes (ecgonine methyl ester, ecgonine ethyl ester, anhydroecgonine methyl ester, m-hydroxybenzoylecgonine, p-hydroxybenzoyl-ecgonine, ecgonine, and anhydroecgonine) were detected for the first time in a wastewater sample.

Sewer surveillance may be a useful tool for epidemiology that would benefit from improved understanding of the fate of microbial agents and prescription antibiotics during conveyance in sewer systems. The aim of this review is to provide an overview of the factors affecting the loading and fate of antibiotics and antibiotic resistant bacteria (ARB) in sewer systems. A review of surveillance studies for antibiotics and antibiotic resistant bacteria is presented. Then, the role of potentially complicating sewer inputs (e.g., the presence of health care facilities in a sewershed),and evidence for temporal variations in antibiotics and ARB are reviewed. Recommendations for best practices for sampling are made. Finally, evidence is presented for in-sewer attenuation of antibiotics and attenuation, growth and gene transfer for ARB. There is potential for, but limited evidence of, sewers serving as a reservoir for ARB growth and horizontal gene transfer. This review highlights the need for better understanding of ARB carriage in the general population and the impact of in-sewer processes on the fate of antibiotics and ARB.