Spatial heterogeneity of antibiotic pollution in chinese lakes: A nationwide study with emphasis on arid zones.

Although most previous studies have illustrated the fate of antibiotics in specific lakes, little is known about their distribution from a nationwide scale due to the insufficient knowledge in arid zones, not even to mention declaring the possible impacts driven by both the climate change and anthropogenic activities. To fill this gap, we selected several typical lakes located in arid region of northwestern China-Xinjiang to assess the occurrence and risks of antibiotics in water and sediment, and then to identity the possible influences of parameters focusing on climate change and anthropogenic activities by comparing with lakes from humid zones. Firstly, 29 kinds of antibiotics were 100 % observed in all arid lakes showing highest level of 506.8 ng/L for water and 22.5 ng/g for sediment with fluoroquinolones (57.6 %) and tetracyclines (36.9 %) being the predominant compositions. The spatial heterogeneity of antibiotic distribution within lakes in arid regions is primarily attributed to factors such as salinity and the physicochemical properties of compounds, whereas the differences between arid and humid regions are mainly driven by temperature and precipitation, which can be inferred by the Antibiotic Normalized Volume Load (ANVL) index used for evaluating the persistence of antibiotics in lakes. Ecologic risks conducted by risk quotients (RQs) and sediment quality index (SeQI) indicated lakes in arid zones were facing high risks than others. Therefore, establishing an ecological zoning control system for antibiotics, not only helps preserve the quality and sustainability of water resources but also safeguards the ecological functions and biodiversity of arid region lakes.