Screening of priority antibiotics in Fenhe River Basin based on the environmental exposure, ecological effects, and human health risk.

Antibiotics in surface water have attracted increasing attention because of their potential threats to aquatic ecosystems and public health. Therefore, it is crucial to develop a priority antibiotic list and establish a regulatory framework for antibiotic control. Taking the Fenhe River Basin in North China as the study area, a method to rank priority antibiotics based on their environmental exposure, ecological effects, and human health risks was established. Twenty antibiotics were detected, with the highest average concentration (118.30 ng/L) of sulfonamides. Among them, azithromycin had the lowest BioWIN3 value, and its logKow value was >4, which means that it has poor biodegradability, is relatively easily adsorbed in the soil or sediment, and is persistent. Additionally, based on a survey of local species with different nutritional structures, the ecological risk thresholds of antibiotics were calculated. The results showed that quinolones had the lowest risk threshold of average value 287.23 ng/L, with a greater potential for a negative effect on the ecological environment. Based on the threshold, norfloxacin, ofloxacin, and erythromycin were identified as the pollutants of ecological risk, their peak concentrations were approximately 2.4 times, 2 times, and 9 times their risk thresholds, respectively, which mainly distributed in the middle reaches. Regarding human health risks, ciprofloxacin posed the highest health risk, with an average health risk entropy of 2.81. Finally, the calculated results of the priority rating of antibiotics showed that ciprofloxacin, enrofloxacin, erythromycin, and azithromycin were the highest-priority antibiotics and should be prioritized in risk management.