Soil microbial community in lead smelting area and the role of sulfur-oxidizing bacteria

The long-term operation of the lead smelter has brought serious heavy metal pollution to the surrounding soil. The microbial community structure and composition of heavy metal contaminated soil is important for the risk assessment and pollution remediation. In this study, a lead smelter operating for more than 60 years was used to investigate the effects of heavy metal pollution on soil microbial community structure and composition in vertical profile. The results showed that the heavy metal content decreases gradually with increasing vertical depth of the soil. The diversity of soil microbial community with moderate pollution was higher than that with low pollution. Regardless of the pollution level, the diversity of soil microbial community was higher in the surface layer than in the bottom layer. The dominant relative abundance genera include Perlucidibaca, Limnobacter, Delftia, Hydrogenophaga, Thiobacillus, Sulfurifustis and Sphingopyxis, showing a higher abundance of sulfur-oxidizing bacteria (SOB). XRD results showed the presence of PbSO4 in soil, may be due to the enrichment of SOB for the oxidation of sulfur. This sulfur cycle characteristic may be potential for the stabilization and remediation of lead (Pb) into PbSO4.