Distribution of the microbial community and antibiotic resistance genes in farmland surrounding gold tailings: A metagenomics approach

Metal mining has caused the accumulation of waste mine tailing dumps from abandoned mines. The pollution of farmlands surrounding metal tailings by heavy metals has been a long-recognized problem. However, the distribution of antibiotic resistance genes (ARGs) in tailings and the main factors influencing this distribution have rarely been reported. In this study, a metagenomics approach was used to investigate the microbial community and ARGs present in farmland surrounding gold tailings in northern China. The results showed that the main pollutants in the farmland were As, Pb, and Cd. Proteobacteria and Actinobacteria were the dominant phyla of microbes in farmlands surrounding gold tailings. A total of 75 ARGs with 327 ARG subtypes were detected in soil samples. Macrolide-, lincosaminide-, and streptogramin B resistant genes accounted for the majority of ARGs in this study, and Actinobacteria, Proteobacteria, and Acidobacteria were the hosts of most ARGs. Partial least squares path modeling revealed that the microbial community was the most influential driver moderating the distribution of soil ARGs near tailings, and heavy metals have direct and partially indirect effects on these ARGs. In contrast to previous analyses of ARGs, our study found that mobile gene elements had a minimal impact on ARGs. Overall, this study presents a complete ARG survey that sheds light on the distribution and fate of ARGs under heavy metal contamination in farmland around gold tailings. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that arsenic, lead, and cadmium were the main pollutants in the farmland surrounding gold tailings. Proteobacteria and Actinobacteria were the dominant phyla of microbes in the area. A total of 75 different ARGs were detected in the soil samples, with macrolide-, lincosaminide-, and streptogramin B resistant genes being the majority.