Recent trends in wastewater-based epidemiology of pharmaceuticals. Methods and applications

This review article discusses the latest research on wastewater-based epidemiology (WBE) of pharmaceuticals since 2020. It covers the analytical methods that have been used to measure pharmaceuticals and their metabolites, mostly relying on off-line solid-phase extraction followed by liquid chromatography-tandem mass spectrometry. Then, we focus on general considerations related to WBE, such as biomarkers stability or back-calculation of drug use by using correction factors. We found that over 130 drugs have been analyzed and their wastewater concentrations converted to pharmaceutical use estimations, of which those related with the nervous system (ATC level 1 code N) have been by far the most frequently investigated. Subsequently the review focusses on studies related to the spatio-temporal assessment of drug use, with a specific section devoted to the impact of COVID-19 pandemic. Then, it covers studies which contrast WBE estimations of drug use with pharmaceutical dispensing data and how they complement each other.