Comprehensive insights into the occurrence, spatiotemporal distribution, source apportionment, and risk assessment of antibiotics in Chaohu Lake.

Antibiotics have attracted significant attention due to their extensive use and associated ecological and drug resistance risks. This study investigates the current concentration status of antibiotics in the surface water and sediments of Chaohu Lake and its surrounding rivers. A total of 46 antibiotics from five major categories were analyzed to assess their distribution and the influence of river inputs. The results indicated that 41 antibiotics were detected in surface water, with concentrations ranging from not detected (ND) to 447.00 ng/L, while 44 antibiotics were detected in sediments, ranging from ND to 192.43 ng/g. Antibiotics were present at all sampling sites, indicating their pervasive occurrence throughout the study area. Among the following rivers, the Nanfei River and Shiwuli River were identified as the primary contributors to antibiotic pollution. Marked seasonal variations were observed: the total antibiotic concentration in water was highest in spring, whereas in sediment it peaked in summer. The prevalence of tetracyclines and quinolones in sediments suggests that distribution coefficients (Kd) play a crucial role in their environmental behavior. Source analysis revealed that livestock discharge and domestic sewage were the primary pollution sources, contributing 33.2% and 25.2%, respectively. Risk assessment showed that Sulfamethoxazole and trimethoprim pose relatively high ecological risks to aquatic organisms. This study provides a valuable, large-scale dataset and valuable insights to support the management of antibiotic contamination in the Chaohu Lake region.