Occurrence and fate of psychiatric pharmaceuticals in the urban water system of Shanghai, China

Psychiatric pharmaceuticals are the most prescribed active substances throughout the world and their presence in the environment raised concerns. The occurrence and fate of 15 selected psychiatric pharmaceuticals, including eight benzodiazepines, four antidepressants, one antiepileptic and two metabolites of benzodiazepines were investigated in wastewater treatment plant (WWTP) influents and effluents, surface water, and final drinking water in Shanghai. Psychiatric pharmaceuticals were in WWTPs influents ranging from low ng L−1 to 68.2 ng L−1, dominated by carbamazepine, doxepin, diazepam and lorazepam. Target analytes were still detected in effluents from low ng L−1 range to 47.3 ng L−1, with carbamazepine, diazepam, and oxazepam as most prevalent. WWTPs were low effective (<50%) in removing most of them, excluding amitriptyline (mean 60%), doxepin (mean 70%), temazepam (mean 78%) and lorazepam (mean 93%). In addition, carbamazepine, diazepam, oxazepam and lorazepam were detected in low ng L−1 to 75.5 ng L−1 in the surface water of Huang Pu Rive. The pattern of contaminants in surface water is similar to the effluent wastewater, which suggested the main source of organic trace pollutants might be WWTPs. Furthermore, carbamazepine (0.8-2.5 ng L−1), diazepam (0.5-3.2 ng L−1) and alprazolam (2.3 ng L−1) were also detected in drinking water and the concentrations were below the health based precautionary value. The investigation was within the range of those results reported in other countries. Our results indicate ubiquity of the investigated compounds in the aquatic system. These pollutants may potentially reach drinking water via WWTP effluents and/or surface waters and require constant attention.