Screening and Prioritization of Antibiotics in Drinking Water Source Based on Risk Assessment, a Case Study in Guangzhou

Comprehensive assessment and screening of prioritized antibiotics are needed to control the increasing antibiotic contamination in drinking water sources. This study investigated 40 antibiotics in the Liuxi River drinking water source in Guangzhou, and conducted the screening and prioritization of antibiotics using a ToxPi-based framework that separately incorporates intrinsic toxicity-related properties and exposure-based ecological and human health risks. The total concentration of the 40 antibiotics was much higher in the dry season than in the wet season. Among all the antibiotics, oxytetracycline and minocycline had the highest concentrations in the dry season, while sulfamethoxazole had the highest level in the wet season. Of all antibiotics, only minocycline and oxytetracycline had high and medium ecological risks in the dry season, respectively. Health risks of all the antibiotics were within an acceptable range. Based on the ToxPi-based prioritization, the ten antibiotics with the highest ToxPi scores (e.g., oxytetracycline and minocycline) were identified as priority compounds for control to reduce potential ecological and human health risks. This study provides a solid reference for the screening and control of antibiotics in drinking water sources.