[Spatial Distribution, Source Apportionment, and Ecological Health Risk Assessment of Antibiotics in the Water Bodies of Huangjia Lake Basin].

To investigate antibiotic pollution in the Huangjia Lake Basin, 28 antibiotics from six classes were analyzed in water samples using solid-phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS). The results revealed the detection of 10 antibiotics spanning five classes (sulfonamides, quinolones, macrolides, lincosamides, and tetracyclines) across 20 sampling sites. Cinoxacin and tilmicosin exhibited the highest detection rates (100%), followed by lincomycin, clindamycin, and chlortetracycline (all >90%). The top three antibiotics by mean concentration were clinafloxacin (33.12 ng·L-1), chlortetracycline (14.84 ng·L-1), and lincomycin (9.33 ng·L-1). Spatial analysis indicated that antibiotic contamination was primarily point-source-dominated with significant heterogeneity. Ecological risk assessment identified elevated risk quotients (RQs) at sites S10, S11, S14, S15, and S16. Clinafloxacin posed high risk (RQ>1), while clindamycin and clarithromycin showed moderate risk (0.1 < RQ < 1). Principal component analysis (PCA) traced antibiotic sources to livestock/poultry farming effluents and aquaculture wastewater. Health risk assessment suggested negligible human health risks from drinking water exposure. Using the Toxicological Priority Index (ToxPi) framework, antibiotics were prioritized as follows: sulfamethoxazole (1.96)>clarithromycin (1.90)>sulfamerazine (1.80)>tilmicosin (1.52). These compounds warrant prioritized attention in future monitoring.