Psychotropic drugs rank among the most prescribed pharmaceuticals in the world. The ubiquitous occurrence of psychotropic drugs in the environment evoked rising concerns due to their various toxic effect on non-target organisms at low concentrations. However, the removal, transformation, and discharging of these drugs throughout wastewater treatment plants (WWTPs) have rarely been reported. Based on the targeted analysis and suspected screening, this study investigated the distribution of psychotropic drugs and their transformation products (TPs) within the entire treatment processes in WWTPs and their receiving rivers. The results indicated that 13 out of 47 psychotropic drugs are widely observed across wastewater, sludge, receiving river water, and sediment, respectively. The aqueous removal efficiencies of most psychotropic drugs exhibited their significant recalcitrance in wastewater treatment processes. For instance, venlafaxine (VEL) was slightly removed by 2.64 % and 10.8 % in these two WWTPs. The concentrations of oxazepam (OZP) and lamotrigine (LMT) dramatically increased after the overall treatment processes due to their metabolic conversion and regeneration processes, respectively. Given the recalcitrance of psychotropic drugs, the identified TPs generated within WWTPs were not abundant, but a wider variety of TPs were identified from human metabolites. A total of 25 TPs were identified via the suspect screening analysis, of which nine were newly identified. In receiving rivers, the risk quotient (RQ) presented OZP, sertraline (SER), and VEL posed high potential risks
the integration of the toxicological priority index (ToxPi) and the toxicity-weighted concentration (TWC) suggested TP-CIT-322 and TP-OCX-195 as the high-priority contaminants. Given the recalcitrance and environmental risks of psychotropic drugs and their TPs in WWTPs and environments, it is crucial for the further exploration of their effective treatment technologies and emission control strategies .