Abstract:The occurrence and fate of eight therapeutic groups, including antibiotics, analgesics, antiepileptics, antilipidemics, antihypersensitives, were studied at a municipal wastewater treatment plant in Chongqing. PhACs were detected using high performance liquid chromatography/tandem mass spectrometry after solid-phase extraction, and the sludge samples were extracted by ultrasonic-assisted extraction before solid-phase extraction. The distribution of PhACs in water and sludge phase was calculated by mass balance analysis. Risk quotients, expressed as the ratios of environmental concentrations and the predicted no-effect concentrations, were used to analyze the ecotoxicological assessment of the target PhACs in the environment. Results showed that all the target pharmaceutically active compounds (PhACs) were present in wastewater, in concentrations ranging from low ng/L to a few μg/L.Among the target PhACs, 18were detected in the sludge samples and most PhACs were found at low ng/g dry weight levels. Only about 1.1% of the total mass load of the studied PhACs was removed by sorption of sludge. The removal of PhACs was insignificant in primary and disinfection processes and was mainly achieved during the secondary treatment. The aqueous removals for the selected PhACs were mainly attributed to the biodegradation processes. Risk quotients were higher than unity for sulfadiazine, sulfamethoxazole, ofloxacinand erythromycin-H2O, in effluent and sludge samples, indicating a significant ecotoxicological risk to human health. Therefore, further removal of PhACs in effluent and sludge is required before their discharge and application to prevent their introduction into the environment.