To keep track of the levels of surface water pollution with human pharmaceuticals and assess the risk of that exposure situation, target monitoring of a selection of prioritized active substances is typically done. However, pharmaceutical consumption data is difficult to access and the market is changing rapidly. Therefore, it is not easy to predict what compounds might occur in the aquatic environment and at what concentrations. An alternative approach to theoretical prioritization is to screen for suspected analytes using high-resolution hybrid tandem mass spectrometry coupled to liquid chromatography (LC-HRMSMS). The hypothesis was that applying a combination of high-resolution screening for suspect masses with exposure prediction would be most effective in detecting new emerging pharmaceutical and thus assessing, as comprehensively as possible, exposure of surface waters to pharmaceuticals. To test this hypothesis, we (i) screened six treatment plant effluents for the exact masses of a list of pharmaceuticals assembled from Swiss, German, and US consumption data and processed the exact mass hits with a number of filters to yield a list of priority suspects that where confirmed/rejected by comparison to purchased standards; (ii) predicted expected concentrations using state-of-the-art exposure prediction approaches and validated the approach against concentrations of a range of target pharmaceuticals; and (iii) assessed the complementarity of both approaches to effectively detect pharmaceuticals with high exposure potential.Starting from 980 candidate pharmaceuticals, 33 priority suspects emerged from exact mass screening and filtering. For 21 of these, reference standards were purchased, and 19 new priority pharmaceuticals were confirmed. The model-based ranking predicted 4 additional substances to have high concentrations which were not prioritised with the analytical screening approach, but which indeed showed sharp peaks at their exact mass upon closer inspection. Therefore, the combination of both approaches is a promising method to assess the exposure of pharmaceuticals in the environment.

Evaluation of analytical and model-based rapid screening approaches to assess exposure of surface waters to human pharmaceuticals

246th National Meeting (2013)

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