东洞庭湖表层沉积物中抗生素及抗性基因的时空分异特征OA北大核心CSTPCD

In order to study the spatio-temporal differentiation of antibiotics and antibiotic resistance genes(ARGs)in the East Dongting Lake,we collected sediment samples from the East Dongting Lake basin in wet and dry seasons and studied 4 classes of 12 antibiotics and 8 corresponding resistance genes using ultra-high performance liquid chromatography-tandem mass spectrometry and real-time fluorescence quantitative PCR.The results showed that the antibiotic concentration level in sediments was ng·g-1,and the detection rate and concentration level of 12 antibiotics in 4 classes were higher in the dry season than in the wet season.The sediment concentration ranges from ND to 176.94 ng·g-1 in the wet season,with an average concentration of 9.75 ng·g-1.In the dry season,the concentration range was ND-101.34 ng·g-1,and the average concentration was 10.88 ng·g-1.Sulfonamides and quinolones are the main antibiotics in East Dongting Lake.A total of 8 ARGs were detected in sediment samples during the wet period,and the absolute abundance range was ND-1.03×107 copies·g-1.The absolute abundance in the dry season ranged from 9.93×102-6.32×109 copies·g-1.Spatially,the total abundance of ARGs downstream was higher than that in the upstream.Antibiotics and ARGs in sediments showed a certain correlation,and the positive correlation was better in the dry season.Our results indicated that the concentration of antibiotics and ARGs in the surface sediments of East Dongting Lake varies significantly with time and space.The pollution level is higher in the dry season and the area close to aquaculture.