Occurrence and ecological-risk levels of antibiotic pollution in the coastal waters of eastern China

Abstract In order to preliminarily explore the distribution of antibiotic pollution in the coastal waters of eastern China, the concentrations of 13 antibiotics in 5 representative coastal rivers in Jiangsu and 21 sampling sites in the coastal waters of Jiangsu were analyzed. The total antibiotic concentrations in the 5 rivers ranged from 33.14 ng L-1 to 417.78 ng L-1, and the total antibiotic concentrations in the 21 sampling sites ranged from 0.90 ng L-1 to 86.33 ng L-1. The concentrations of antibiotics in a sampling site decreased as the distance of the sampling site from the coastline increased, indicating that river inputs are important sources of antibiotic pollution in the coastal waters of Jiangsu. The detection rates of roxithromycin, lincomycin, azithromycin, and sulfamethoxazole in the rivers and sampling sites were above 70%. Correlation analysis showed that the concentrations of antibiotics were positively correlated with the levels of total phosphorus and chemical oxygen demand. An ecological risk assessment revealed that roxithromycin posed a moderate risk to aquatic organisms in the coastal waters of Jiangsu. The results of this study highlight the significance of monitoring and controlling the concentrations of antibiotic contaminants in the coastal waters of Jiangsu.