砷尾矿污染土壤的细菌群落结构多样性及其相关环境影响因子分析

以湖南石门雄黄尾矿污染土壤为对象,研究纵向不同深度、横向不同距离土样中的重金属污染程度以及细菌群落结构变化规律,查明砷污染土壤的核心微生物组成并将其与土壤理化指标进行共存网络图分析.结果表明:该尾矿区的土壤各项重金属指标严重超标,尤以铅(626.54 mg·kg?1,Ei=105.48)、砷(1804.75 mg·kg...

Analysis of Microbial Community Structure and Environmental Impact Factorsof Arsenic Mine Tailings

In the study,we investigated the degrees of heavy metal pollution and patterns of microbial community composition at various depths and distances in a Hunan shimen realgar mine tailings,to identify the core microbes in arsenic contaminated soil and the soil physico-chemical properties influencing these microbes.The results showed that the heavy metal indexes in the mine tailings were remarkably higher than the standards,especially for lead(626.54 mg·kg^?1,Ei=105.48),arsenic(1804.75 mg·kg^?1,Ei=565.75),and cadmium(31.46 mg·kg^?1,Ei=7491.5).There was a significant positive correlation between soil sampling depth and the comprehensive potential ecological risk index(RI)of heavy metals(r=0.79,P=0.000),while a significant negative correlation between RI and sampling distance was detected(r=?0.85,P=0.000).The dominant phyla in all samples were Proteobacteria(54.35%±17.16%)and Actinobacteria(22.39%±10.64%).As for genus level,the relative abundance of Pseudomonas(16.47%±11.84%),Acinetobacter(8.07%±7.11%),and Acidithiobacillus(7.53%±14.68%)were relatively high.The 26 taxa shared in all samples accounted for more than 90%of the total average relative abundance of the whole microbial communities,although the relative abundance of each specific genera varied largely among different samples.Specifically,Ferroplasma,Acidithiobacillus,Sulfobacillus,Lactobacillus,and Nitrospira were dominant in soil samples collected at different longitudinal depths.The coexistence network analysis(correlation coefficient r≥|0.6|,or P<0.05)revealed that some taxa were positively correlated with concentrations of ferrous,free arsenic,and cadmium,but were negatively correlated with pH.As for soil samples collected transversely,Acidiphilium,Pseudomonas,Corynebacterium,and Thiobacillus were the most abundant lineages.Some taxa were positively correlated with total arsenic and lead,while negatively correlated with combined or encrusted arsenic.In summary,we analyzed the environmental pollution risk of multiple heavy metals originated from the arsenic mine tailings and investigated the correlations between heavy metals and the core microbes,which might provide a theoretical basis for screening potential heavy metal resistant bacteria or engineered bacteria.