Source Apportionment and Risk Assessment of Antibiotics in the Water Bodies of the Nanjing Tributary of the Yangtze River: A Case Study of Jinchuan River

This investigation used solid-phase extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) to analyze antibiotic pollution patterns in the Jinchuan River, a tributary of the Yangtze River in Nanjing. By quantified five major antibiotic classes-quinolones, macrolides, sulfonamides, tetracyclines, and penicillins-in surface water to identify the pollution sources and assess the ecological risks. Results show that the antibiotic concentrations ranging from n.d. to 273.06 ng·L^-1, with a mean concentration of 229.37 ng·L^-1. Comparative analysis revealed significantly elevated antibiotic levels in the Jinchuan River relative to the level in the main Yangtze River channel. Source apportionment modeling identified four primary contamination sources: the effluents of municipal sewage treatment plants constituted the predominant sourc (48.5%), followed by non-centralized domestic wastewater discharges (29.2%), aquaculture wastewater (15.5%), and pharmaceutical manufacturing effluents (6.8%). Ecological risk assessment using risk quotients (RQ) indicated elevated concerns for enoxacin, roxithromycin, and clarithromycin (RQ>0.1), whereas other detected antibiotics exhibited minimal ecological impact (RQ < 0.1). Additionally, most antibiotics posed a low risk for developing resistance. These findings provide a scientific foundation for targeted antibiotic pollution control and risk management strategies.