Objective To understand the status of antibiotic contamination in drinking water in Ma′anshan city, Anhui province and assess the ecological and human health risks of antibiotics, thus providing a scientific basis for drinking water management and antibiotic contamination control.

Methods In 2024, 36 drinking water samples were collected. Solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry was employed to measure the concentrations of 13 antibiotics of 4 categories in source water, finished water, and tap water. Ecological and health risks were assessed for the detected antibiotics.

Results A total of 7 antibiotics of 3 categories were detected, with the detection rates ranging from 0.00% to 75.00% and concentrations ranging from ND (not detected) to 43.70 ng/L. The antibiotic with the highest concentration was enrofloxacin (43.70 ng/L). The water treatment process demonstrated good removal efficiency for antibiotics, with a removal rate of 89.97%. Specifically, sulfamethoxazole, sulfachloropyridazine, and clarithromycin were completely removed (100.00%). In source water, sulfachloropyridazine and clarithromycin showed no ecological risk to three aquatic organisms, while sulfamethoxazole and enrofloxacin showed no ecological risk to invertebrates and fish but exhibited low-level ecological risk to algae. Under the premise of using the most sensitive species, algae, as an indicator, the combined toxicity of antibiotics posed a moderate ecological risk. Among the detected antibiotics, clarithromycin had the highest health risk quotient (RQ_H), which, however, was less than 1×10⁻², indicating negligible health risks to people of all age groups. The combined effect of antibiotics showed the RQ_sum < 1×10⁻², presenting an increasing-decreasing-increasing trend.

Conclusions Antibiotic contamination in the drinking water in Ma′anshan is primarily dominated by enrofloxacin. The combined effect of antibiotics poses a moderate ecological risk.