[Level of Typical Antibiotics in Effluent from Beijing Wastewater Treatment Plants]

To investigate the concentration level of antibiotics in the effluent of Beijing's wastewater treatment plants （WWTPs）, ultra-performance liquid chromatography/tandem mass spectrometry （UPLC-MS/MS） was used to detect antibiotics in the effluent of nine WWTPs in Beijing, and the effects of the WWTPs process and the years of construction and other factors on the antibiotic level were analyzed. The correlation between antibiotics and conventional water quality indicators, anionic active agents, and heavy metals was analyzed. The results showed that a total of 13 antibiotics in four categories were detected in nine WWTPs, with total concentrations ranging from 16.18 to 330.02 ng·L^-1, among which sulfapyridine, roxithromycin, clarithromycin, and azithromycin were detected at a rate of 100%； sulfadimethoxine was detected at a rate of 88.9%； and sulfadoxine, sulfachloropyridazine, and ofloxacin were detected at a rate of 77.8%. In terms of the average detection concentration, the highest were ofloxacin, roxithromycin, and sulfapyridine, respectively, at 43.83, 13.89, and 7.51 ng·L^-1. Compared with other WWTPs in China and abroad, the concentration levels of sulfonamides and quinolones in the effluent of Beijing's WWTPs were significantly lower. Among the macrolide antibiotics, clarithromycin was detected at a relatively low concentration level, and the remaining types were comparable to those of other WWTPs. Correlation analysis of antibiotic concentrations with conventional water quality indicators, anionic active agents, and heavy metals showed that sulfonamide antibiotics had no significant correlation with most of the indicators mentioned above, whereas macrolide antibiotics were positively correlated with TP, BOD, anionic active agents, etc.