Antibiotic resistance gene abundances associated with heavy metals and antibiotics in the sediments of Changshou Lake in the three Gorges Reservoir area, China

Human activities have very important influence on the migration and transformation of antibiotics and antibiotic resistance genes (ARGs). In the present study, Changshou Lake, located in the Three Gorges Reservoir area, was selected to investigate the abundance of heavy metals, antibiotics and ARGs. In addition, the environmental risks of the antibiotics were evaluated and the relationships between heavy metals and antibiotics/ARGs were assessed. Higher concentrations of antibiotics and ARGs were observed in the ecological aquaculture area of the Changshou Lake. The results suggested that the ecological risk of tetracycline and sulfamethoxazole was relatively higher than that of other antibiotics. The results of the cumulative risk quotient showed that the target antibiotics of the ecological aquaculture area (sites C1 and C3) seriously threaten the ecological environment of Changshou Lake, and antibiotic pollution in the sediment environment cannot be ignored. Especially for the tetracycline ARGs, there was a positive relationship among efflux pump genes (tetA, tetC and tetG) at the P < 0.05 level, and there was also a strong correlation between the ribosomal protection protein genes, except tetQ. The joint pollution of heavy metals and antibiotics in Changshou Lake may be due to the cage aquaculture in the early stage of the lake. In addition, positive significant correlations were observed between ARGs/antibiotics and heavy metals in Changshou Lake, highlighting the potential pressures of heavy metals on the ARGs/antibiotics.