Psychiatrics and selected metabolites in hospital and urban wastewaters: Occurrence, removal, mass loading, seasonal influence and risk assessment.

The occurrence, removal, mass loading, seasonal influence and environmental risk assessment of nine psychiatric pharmaceuticals and four of their selected metabolites, were studied in one hospital and one urban wastewater treatment plant (WWTP) in Ioannina city, in northwestern Greece, providing information about the efficiency of the plants and their contribution into the final receiver's flow. Samples were collected from the influents and the effluents of the plants in different sampling campaigns, from July to December 2016. Analytical methodology was based on ultra-high performance liquid chromatography-Orbitrap high-resolution mass spectrometry, after solid-phase extraction through Oasis HLB cartridges. Concentrations in both WWTPs ranged between <LOQ and 1126.3 ng/L in the influents and between <LOQ and 1127.4 ng/L, in the effluents. Results indicated that venlafaxine and its metabolite O-desmethyl venlafaxine were the most frequently detected compounds in the influents and the effluents of both WWTPs. Metabolite to parent compound ratio ranged in the influents between 0.01 and 87.2 while in the effluents between 0.01 and 47.7. Based on mass loads in the influents, venlafaxine is consumed in high amounts (up to 67.1 mg/day/1000 inhab.), and consequently its metabolite O-desmethyl venlafaxine (up to 139.1 mg/day/1000 inhab.). Similarly to the influents, environmental emissions, were also higher for venlafaxine and O-desmethyl venlafaxine (10.1 and 13.3 mg/d/1000 inhab., respectively). Removal efficiencies in the hospital WWTP ranged from -100% to 98.9%, while in the city WWTP from -49.9% to 99.8%. Furthermore, an important outcome was the evaluation of the potential ecotoxicological risk, by means of risk quotients (RQs), where none of the target psychiatrics or their metabolites showed RQ above 1.