Abstract:

With the development of our country's mining industry, antimony (Sb) mining process can cause Sb pollution in the surrounding water environments, posing potential risks to the surrounding ecological environment and human health. Microorganisms are one of the main driving forces of the biogeochemical cycle of Sb pollutants in rivers. They regulate the valence transformation process of Sb through oxidation/reduction process, thus changing the toxicity and mobility of Sb. In this paper, we took Sb polluted river sediment in Dushan County, Guizhou Province as the research object, and used the methods of geochemical parameter analysis, high-throughput sequencing and statistical analysis to study the distribution of Sb concentration in the river sediment and its selective effect on the river sediment microbial community. The results showed that the concentration of Sb in the river sediment gradually decreased with the increase of the distance from the sewage outlet of Sb smelting plant, which might be caused by the fact that Sb (III) produced by microbial reduction was easy to combine with iron and manganese compounds and precipitate under anaerobic environment. Based on the random forest analysis, it was found that Sb was the main factor shaping the microbial community structure of river sediment, and the microbial diversity of river sediment showed a gradual increasing trend with the decrease of Sb concentration. According to LEfSe difference analysis, Sb was the key driving factor of microbial community composition evolution in river sediment. Different microorganisms were enriched in different Sb polluted environments. Combined with co-occurrence network analysis, it was found that Paludibacter and Saccharofermentans were the keystone in Sb polluted river sediment. The relative abundance was significantly and positively correlated with the concentrations of Sb_tot and Sb(III), suggesting that these key microorganisms played an important role in the biogeochemical cycle of Sb, especially in regulating the reduction process of Sb.

Key words: antimony, river sediment, keystone, microbial community, co-occurrence network analysis, Antimony reducing bacteria

摘要：

锑（Sb）矿的开采会造成周边水环境发生Sb污染，对周边生态环境和人体健康造成潜在风险。微生物是河流中Sb污染物生物地球化学循环的主要驱动力之一，通过氧化/还原过程调控Sb的价态转化过程，从而改变Sb的毒性和流动性。以贵州独山县Sb污染河流底泥为研究对象，利用地球化学参数分析、高通量测序和统计分析等方法，研究Sb污染河流底泥中Sb的浓度分布规律及其对河流底泥微生物群落的选择性影响。结果表明，随着与Sb冶炼厂排水口距离的增加，河流底泥中Sb浓度逐渐降低，这可能是微生物还原产生的Sb(III) 在厌氧环境下易与铁锰化合物结合形成沉淀所导致的。基于随机森林分析发现，Sb是塑造河流底泥微生物群落结构的主要因素，河流底泥微生物多样性随Sb浓度的降低而呈现逐渐增加的变化趋势。通过LEfSe差异分析可知，Sb是河流底泥微生物群落结构组成演变的关键驱动因子，在不同Sb污染环境下富集了差异微生物。结合共现网络分析，发现栖泥沼杆菌属Paludibacter和糖发酵菌属Saccharofermentans是Sb污染河流底泥中的核心微生物，其相对丰度与Sb_tot、Sb(III) 浓度呈显著正相关，表明这些关键微生物对Sb生物地球化学循环发挥重要作用，尤其对调控Sb的还原过程具有重要潜力。

关键词: 锑, 河流底泥, 微生物群落, 关键微生物, 共现网络分析, 锑还原菌