Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China.
Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
Sci Total Environ. 2020 Apr 15;713:136451. doi: 10.1016/j.scitotenv.2019.136451. Epub 2020 Jan 7.
Antimony (Sb) and arsenic (As) are toxic elements that occur widely in trace soil concentrations. Expansion of mining activities has increased Sb and As pollution, thus posing a severe threat to human welfare and ecological systems worldwide. Knowledge regarding the composition and adaptation of the microbial communities in these metal(loid) contaminated sites is still limited. In the current study, samples along a river flowing through the world's largest Sb mining area (Xikuangshan) were selected to investigate the microbial response to different Sb or As species. A comprehensive analysis of geochemical parameters, high-throughput sequencing, and statistical methods were applied to reveal the different effects of Sb and As on sedimentary microorganisms. Results suggested that the majority of the Sb and As fractions were not bioavailable. The Sb extractable fraction had a stronger effect on the microbial community compared with its As counterpart. Random forest analyses indicated that the easily exchangeable Sb fraction and specifically sorbed surface-bound fraction were the two most selective variables shaping microbial community diversity. A total of 11 potential keystone phyla, such as bacteria associated with the Bacteroidetes, Proteobacteria, and Firmicutes, were identified according to a molecular ecological network analysis. Strong correlations (|R| > 0.7, P < 0.05) were identified among the indigenous microbial community and pH (negative), sulfate (negative), and exchangeable Sb fraction (positive). Bacteria associated with the genera Geobacter, Phormidium, Ignavibacterium, Desulfobulbus, Ferruginibacter, Fluviicola, Methylotenera, and Scytonema, were predicted to tolerate or metabolize the Sb extractable fraction.
锑（Sb）和砷（As）是广泛存在于痕量土壤浓度中的有毒元素。采矿活动的扩张增加了 Sb 和 As 的污染，从而对全球人类福利和生态系统构成了严重威胁。关于这些金属（类）污染地点微生物群落组成和适应的知识仍然有限。在本研究中，选择了流经世界上最大的 Sb 矿区（锡矿山）的河流沿线的样本，以研究微生物对不同 Sb 或 As 物种的反应。通过综合分析地球化学参数、高通量测序和统计方法，揭示了 Sb 和 As 对沉积物微生物的不同影响。结果表明，大部分 Sb 和 As 形态都不可生物利用。可提取 Sb 形态对微生物群落的影响强于其 As 对应物。随机森林分析表明，易交换 Sb 形态和特定的表面结合的束缚 Sb 形态是塑造微生物群落多样性的两个最具选择性的变量。根据分子生态网络分析，共鉴定出 11 个潜在的关键门，如与拟杆菌门、变形菌门和厚壁菌门相关的细菌。土著微生物群落与 pH 值（负相关）、硫酸盐（负相关）和可交换 Sb 形态（正相关）之间存在强烈的相关性（|R|>0.7，P<0.05）。与 Geobacter、Phormidium、Ignavibacterium、Desulfobulbus、Ferruginibacter、Fluviicola、Methylotenera 和 Scytonema 属相关的细菌被预测能够耐受或代谢可提取 Sb 形态。
