Distribution and risk assessment of antibiotics in surface water of the Yangtze River Basin

Antibiotics in surface water have raised growing concerns due to their potential threats to aquatic ecosystems and public health. This study takes the Yangtze River Basin as the study area, and systematically collects and analyzes the concentration data of antibiotics in surface water, determining the level and distribution characteristics of antibiotics in surface water of the Yangtze River Basin and exploring its potential ecological and health risks. Results revealed 72 detected antibiotics in the Yangtze River Basin with concentrations ranging from 0 to 3075 ng·L^-1, quinolones showed the highest concentrations and detection rates, followed by sulfonamides, while tetracyclines and macrolides exhibited lower levels. Spatially, antibiotic concentrations displayed an increasing trend from upstream to downstream regions. The results of the two risk assessments indicated that antibiotics such as sulfamethoxazole, doxycycline, tetracycline, roxithromycin, azithromycin, clindamycin, norfloxacin, and ciprofloxacin have high ecological risk and should be prioritized for control. Health risk evaluation indicated that tetracycline, ofloxacin, and ciprofloxacin in certain water sources posed varying health risks across different genders and ages. These findings provide a scientific basis for the prevention and control of antibiotic pollution in the Yangtze River Basin.