Objective To investigate the current status of antibiotic contamination and its ecological risk in three major water bodies including Yangtze River, Taihu Lake, and Huai River in Jiangsu province, and to provide scientific basis for the drinking water safety and antibiotic contamination prevention work.

Methods Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to measure the concentrations of 39 commonly used antibiotics from five categories in the three water bodies. The risk quotient (RQ) was calculated according to the European Environmental Risk Technicai Guidelings (Guideline on the environmental risk assessment of medical products for human use), and the ecological risk of antibiotics in the water bodies was evaluated using the method proposed by Hernando et al.

Results Among the 39 kinds of antibiotics, 20 kinds were detected. The overall detection rate of antibiotics in the three major water bodies was 51.3% (20/39); roxithromycin had the highest detection rate of 70% (21/30); the three major water bodies showed different antibiotic detection rates as Yangtze River > Huai River > Taihu Lake; there were significant differences in the detection rates of penicillins (χ²=16.304, P < 0.05), sulfonamides(χ²=13.585, P < 0.05), and quinolones(χ²=6.347, P < 0.05) between the three major water bodies. Ampicillin, penicillin V, erythromycin, sulfacetamide, and sulfamethoxazole were detected at concentrations greater than 10 ng/L, and erythromycin showed the highest concentration of 36.24 ng/L. There were significant differences in the mean values of the different antibiotic contaminants in the source water (H=87.612, P < 0.01). The RQ values of erythromycin in the Yangtze River and sulfamethoxazole in the Taihu Lake were ≥ 1, which showed a high ecological risk level; the RQ values of ampicillin and sulfamethoxazole in the Yangtze River and Huai River were 0.1~1, which showed a medium ecological risk level; the RQ value of ampicillin in the Taihu Lake was ≤ 0.1, which showed a low ecological risk level.

Conclusion The degree of antibiotic contamination in the three major water bodies in Jiangsu province is Yangtze River > Huai River > Taihu Lake. The concentration level of antibiotics in the water bodies were relatively lower than that of other regions, but the polluting antibiotics have different ecological risks in different water bodies, which is a threat to the ecological stability, water safety and human health.