Psychotropic drugs in drinking water? A scoping review of evidence on diazepam and fluoxetine

Abstract The global prevalence of mental disorders has increased considerably in recent decades. This evidence, associated with population growth and the expansion of access to medications, favors the growing global consumption of psychotropic drugs. Consequently, an increasing load of these substances is introduced into the environment, especially into water bodies, characterizing them as emerging contaminants. This scoping review study aimed to integrate data and provide a global overview of the occurrence of widely used psychotropic drugs (diazepam, fluoxetine, and haloperidol) in drinking water. The search for studies was conducted across 7 databases, with no language or publication year restrictions. We included only original studies in this review and synthesized data from the included studies for water sampled, sampling location, year of sampling, analytical method used, psychotropic drug found, and concentration found. Our review identified 13 studies published between 2000 and 2024 on the occurrence of diazepam and fluoxetine in tap water, drinking water, bottled water, and drinking well water from 7 countries, with concentrations ranging from 0.2 to 300 ng/L. No studies on the occurrence of haloperidol in drinking water were found. Our data highlight that the occurrence of psychotropic drugs in drinking water is a growing global reality and also show a significant lack of research dedicated to the topic. Furthermore, the results of this scoping review reinforce the need to expand water quality monitoring, improve analytical techniques, invest in advanced water treatment technologies, and implement public policies on the proper disposal of medication and the control of drug pollution.