Effects of bactericides and sulphate reducing bacteria addition on acidification and microbial community structure of newly produced coal gangue

Microbiologically driven acidic pollution of coal gangue has become a major environmental problem in coal gangue dumps in coal mining areas. Addition of bactericides and sulphate reducing bacteria (SRB) is an effective means to control the acidic pollution of coal gangue, but their mechanism of action has not been fully investigated. By adding bactericide, SRB and bactericide-SRB to the newly produced coal gangue, respectively, the effects of these treatments on the microbial community structure were observed. Changes in pH and electrical conductivity (EC) of the gangue leaching solution, as well as the microbial community composition and functional abundance on the gangue surface were analysed by leaching simulation experiments and 16S rRNA sequencing. The results showed that (1) the addition of bactericide-SRB was the most effective treatment to elevate pH before 8 d, while the addition of SRB performed best after 22 d (2) The addition of bactericide and SRB drastically changed the microbial community structure on the gangue surface. Simultaneous addition of both had the best inhibitory effect on pathogenic bacteria and Thiobacillus. (3) All three treatments promote higher abundance of genes related to nitrogen cycling, but reflected in different gene functions. Microorganisms with sulfate respiration function in the experimental group all showed different increases. The abundance of other sulfur cycle genes decreased substantially. However, Human Pathogens All had higher abundance than control check (CK) in each treatment, which may indicate that the addition of either bactericides or SRB increases the risk of microbial pathogenicity to humans. (c) 2025 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.