Antimicrobials are released into the environment in different ways, but primarily through the discharge of effluents from wastewater treatment plants (WWTPs) and water run-off from manure-treated agricultural lands. WWTP effluents have been identified as one of the major sources of antimicrobials and other pharmaceuticals in the environment. The use of High Resolution Mass Spectrometry (HRMS) has gained interest in the recent years because of its ability for suspect screening, a technique wherein only information about the chemical structure of the compounds is needed, and the list of compounds to be screened may be tailored depending on the focus and purpose of the study. In this presentation, wastewater and surface water samples from different locations around the world were analyzed using a targeted method for antimicrobials. The same set of samples were also screened for micropollutants using a suspect list which contains almost all known antibiotics, a few major transformation products, substances with antibiotic properties, and other emerging contaminants in the environment. Analysis of samples revealed differences in the antimicrobial profiles in samples collected from Asia, Europe, and the USA. The contaminant loading will be presented as a total of all the antimicrobials detected, sorted into four compound classes, sulfonamides, macrolides, tetracylines, and quinolones. For the non-targeted analysis, Compound Discoverer<sup>TM </sup>was used to analyze the data post – acquisition. The fragmentation pattern of the suspect hits were compared to the mzCloud database, which is embedded in the Compound Discoverer<sup>TM </sup>software. Each of the peaks were inspected manually, and the structures of the predicted compounds were checked. Peaks with signals that were not three times more than the background noise, and structures which were not ionizable in positive mode, were removed from the list. Standards for some of the compounds in the list were available in the laboratory and were then ran in the same method as the samples in order to compare the retention times and the MS2 fragmentation pattern. Compounds that were confirmed to be present in the samples are: tramadol, thiabendazole, metalaxyl, imazalil, diuron, dichlorvos, DEET, and carbendazim. Standards need to be purchased in order to confirm the remaining compounds in the list.

Global reconnaissance of antimicrobials and other emerging contaminants in surface water by target and non-target LC/MS/MS analysis

2019 Fall National Meeting

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