Comprehensive insight into the occurrence characteristics, influencing factors and risk assessments of antibiotics in the Chaohu Basin

The pollution of antibiotics in aquatic environments has received extensive attention. Yet, research on antibiotic contamination in river-lake systems, a significant form of modern aquatic environments, still needs to be explored. This study focuses on the Chaohu Basin (China) investigating the occurrence characteristics, influencing factors, and risk assessments of antibiotics in the river-lake system. The total antibiotic concentrations in the water phase and sediment phase were 3.14–1887.49 ng/L and 0.92–1553.75 ng/g, respectively. Clindamycin was the predominant antibiotic in the water phase, whereas tetracycline prevailed in the sediment phase. Notable differences in concentration and structural composition of antibiotics between the tributaries (river system) and Chaohu Lake were observed, indicating the involvement of various geochemical processes in the attenuation of antibiotics during transport to the receiving lake. Spatial analysis suggested that the western river is the primary source of antibiotics in Chaohu Lake. Controlling nutrient influx in heavily polluted areas is crucial to addressing the escalating issue of antibiotic pollution in the river-lake system. The widespread occurrence of clindamycin in the waters is likely due to wastewater treatment plant discharges, and high-intensity human activities continue to exacerbate antibiotic contamination. Risk assessment indicated that sulfamethoxazole, tetracycline, lincomycin, and clindamycin ranked in the top four with the highest risks to the most sensitive aquatic organisms. Nonetheless, the antibiotics presented no risk to consumer health. This study provides valuable insights for controlling antibiotic pollution in riverlake systems.