Microbial diversity in soils from antimony mining sites: geochemical control promotes species enrichment

Renjian Deng, Zhie Tang, Baolin Hou, Zhenghua Wang, Chuanqu Zhu, Steven Kelly, Andrew Hursthouse*

*Corresponding author for this work

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Abstract

Elevated soil concentrations of antimony and co-contaminants are frequently encountered where antimony has been mined on a large scale. The Xikuangshan antimony mine in central South China has sustained, over many centuries, dispersed and spatially variable input of potentially toxic elements into the local soil ecosystem. We utilized this unique environment to assess the impact of chemical conditions (absolute and available fractions of toxic elements and disrupted soil properties) on soil microbiology, using high throughput sequencing and statistical analysis (principle component analysis and canonical correspondence analysis). The toxic element concentrations were between 970 - >24,000 mg/kg for Sb, with associated As, Pb, Cd and Hg at >3, >10, >590 and > 30 x the regional background values respectively, with 5-10% of the total soil Sb being environmentally mobile. Microbial diversity was high and soil properties (pH and organic matter, iron and sulfate) influence absolute microbial activity. We identified strong positive and negative correlations with specific bacterial taxonomic groups which show: a. intolerance of available fractions, all elements (e.g. Gemmatimonas, Pirellula, Spartobacteria) b. good tolerance of available fractions, all elements (e.g. Povalibacter, Spartobacteria) and c. mixed response, tolerating available Sb, Hg and Cd and inhibition by As, Pb (e.g. Escherichia/Shigella and Arthrobacter) and in reverse (e.g. Gemmatimonas, Sphingomonas). The site hosts great diversity dominated by Gram negative organisms (many with rod (bacillus) morphologies but also some filamentous forms) and a wide range of metabolic capabilities (anaerobes e.g. Saccharibacteria, metal oxidising e.g. Geobacter, chemoautotrophs e.g. Gemmata, sulfur reducing e.g. Desulfuromonas). The bioremediation potential of Arthobacter and Escherichia/Shigella for Sb control is highlighted.
Original languageEnglish
Number of pages12
JournalEnvironmental Chemistry Letters
DOIs
Publication statusPublished - 24 Feb 2020

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Keywords

  • Potentially toxic elements (PTE) contamination
  • Antimony mine
  • Soil microbial population structure
  • High-throughput sequencing
  • Canonical correspondence analysis (CCA)

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