Psychotropic pharmaceuticals in aquatic environments: Occurrence and analytical challenges

Psychotropic pharmaceuticals, such as antidepressants, anxiolytics, antiepileptics, antipsychotics, and hypnotics, are frequently found in aquatic environments, raising growing concerns due to their persistence, bioactivity, and potential for trophic transfer. This review offers a comprehensive examination of the environmental presence of all psychotropic compounds reported in the most significant studies to date. It includes a critical analysis to identify the most frequently studied substances and geographic detection patterns. These compounds and their transformation products (TPs) have been detected in surface waters, wastewater, sediments, and aquatic organisms at concentrations ranging from ng/L to μg/L. Antidepressants such as fluoxetine, sertraline, and venlafaxine, along with anxiolytics like diazepam, alprazolam, and oxazepam, are among the most commonly reported. Environmental concentrations often exceed 1000 ng/L, particularly in untreated or insufficiently treated effluents. Transformation products, such as O-desmethylvenlafaxine, norfluoxetine, and carbamazepine-epoxide, are also prevalent and may occur at levels exceeding those of their parent compounds, indicating persistence and potential toxicity. The review also examines the main analytical methods used for detection, with solid-phase extraction (SPE) coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) being the most widely employed due to their high sensitivity and selectivity. A scientometric overview complements the discussion, highlighting research trends and regional monitoring gaps. This review advocates for harmonized regulation, improved detection of TPs, and integrated environmental strategies.