Antibiotics and antibiotic resistance genes (ARGs) are highly concerning emerging polltants. Wastewater treatment plants (WWTPs) are considered to be one of the most important anthropogenic sources of antibiotics and ARGs in the environment. Six WWTPs of a city were selected to investigate the antibiotics and ARGs in the influents and effluents, respectively. In total, 73 kinds antibiotics belonging to 7 classes were detected in WWTPs. The total concentration of those antibiotics ranged between 490.2-2288.6 ng·L-1, and ofloxacin, maprofloxacin, and roxithromycin were the most frequently detected antibiotics in the influents. A dramtic difference was observed in the antibiotic removal efficiency among the WWTPs, and the total antibiotic concentration in the effluents ranged between 260.2-1464.3 ng·L-1. Macrolides and quinolones are the main classes in the effluents, and the antibiotic concentration in the effluents was higher than that in the influents. Ten kinds of ARGs were detected in the WWTPs. Among these, sul Ⅰ was the most widely prevalent with an absolute abundance of 2.4×105-5.4×106 copies·mL-1. No significant difference in ARG abundance was observed between industrial wastewater and domesic wastewater. Furthermore, the correlation between ARG abundance and antibiotic concentrations weakened after treatment in the WWTPs.
Keywords: antibiotic resistance genes(ARGs); antibiotics; correlation; distribution characteristics; wastewater treatment plant.