[Occurrence and environmental risks of antibiotics in surface water of China]

Antibiotics as emerging pollutants are frequently detected in surface water, raising concerns about the associated risk of antibiotic resistance genes (ARGs). Despite the widespread apprehension, there are still research gaps in the occurrence of antibiotic pollution in surface water and the associated ecological risks to aquatic organisms in China. Here, we established a dataset of antibiotic pollution in surface water in China during 2018-2022, which encompassed 3 368 concentration values of 128 antibiotics reported in 124 articles. Our analysis showed that antibiotic concentrations were predominantly in the ng/L-μg/L range, reaching up to 26 μg/L. Notably, sulfonamides (e.g., sulfamethoxazole) and quinolones (e.g., ciprofloxacin) were frequently reported at high concentrations. The pollution degree of antibiotics represented by sulfamethoxazole, ciprofloxacin, roxithromycin, and tetracycline exhibited no significant variation across different years but was lower in summer than that in spring and autumn. Additionally, distinct spatial distribution characteristics of the pollution were observed. According to calculation results of the aquatic ecological risk assessment model and the weighted frequency, we proposed a list of priority antibiotics including clarithromycin, erythromycin, sulfamethoxazole, ofloxacin, and oxytetracycline in surface water. Last but not least, this study points out the deficiencies in current research on the occurrence and ecological risks of antibiotics in surface water of China and provides viable screening strategies and monitoring recommendations in this context.