While antibiotics are widely used, their misuse has become a global issue. Due to anthropogenic activities such as terrestrial runoff and marine aquaculture, the types and concentrations of antibiotics in Laizhou Bay (LZB) have been continuously increasing. Based on the survey data in August 2022 and April 2023, we analyzed the spatiotemporal distribution of antibiotics in LZB and its controlling factors. The results revealed that all targeted antibiotics, except for sulfacetamide, were detected in LZB. Total detected concentrations in surface water, SPM, and sediments were 2.32-116.4 ng/L, 142.9 – 17694 ng/g, and 3.77-29.7 ng/g, respectively, indicating that antibiotics in the aquatic environment were primarily enriched in SPM. The antibiotics spatiotemporal variations in LZB were significant. Due to the southern river inputs and aquaculture activities, antibiotic concentrations in surface water were higher in the southwest LZB. The Yellow River transports a significant amount of sediment and deposits in estuary, resulting in a higher antibiotic content in the sediments near the Yellow River estuary. These findings contribute to a better understanding of antibiotic behavior and impact in LZB and provide a scientific basis for preventing and controlling antibiotic pollution.
 

Layzhou Bay; Antibiotics; Spatial and temporal distribution; Risk assessment