Detection, occurrence and fate of 22 psychiatric pharmaceuticals in psychiatric hospital and municipal wastewater treatment plants in Beijing, China

The liquid chromatography–electrospray ionization-tandem mass spectrometer (LC–MS/MS) method coupled with an automated solid-phase extraction procedure has been developed to identify 22 psychiatric pharmaceuticals, including seven anxiolytic-sedative-hypnotics, six antidepressants, and nine anti-schizophrenia drugs, in wastewater samples from two psychiatric hospital wastewater treatment plants (P-WWTPs) and three municipal wastewater treatment plants (M-WWTPs) in Beijing, China. Analyte recoveries from spiking experiments in the WWTP influent and effluent at three concentrations ranged from 70% to 110%, excluding sulpiride, ziprasidone, and olanzapine. Method detection limits for five, eight, and nine analytes in the WWTP influent and effluent were 20–80, 1–16, and <1 ng L−1, respectively. High psychiatric pharmaceutical concentrations (e.g., ∼942 ng L−1oxazepam, 5552–12,782 ng L−1 clozapine, 2762–9832 ng L−1sulpiride, and 2030–4967 ng L−1quetiapine) were frequently observed in P-WWTP influent compared to M-WWTPs. Although P-WWTPs typically had higher removal rates, significantly higher concentrations of the target compounds were observed in the P-WWTP secondary effluent than in the M-WWTP influent (e.g., ∼752 ng L−1oxazepam, ∼8183 ng L−1 clozapine, ∼10,833 ng L−1sulpiride, and ∼1168 ng L−1quetiapine). Thus, the discharge control of psychiatric pharmaceuticals from psychiatric hospitals requires improvement.

► We developed LC–MS/MS analysis of 22 common psychiatric pharmaceuticals in wastewater. ► Higher influent pharmaceutical concentrations were observed in P-WWTPs than M-WWTPs. ► Higher effluent pharmaceutical concentrations in P-WWTPs with higher removals. ► Pharmaceutical removals mainly happened in the secondary treatment of these WWTPs.