Water-soluble mercury induced by organic amendments affected microbial community assemblage in mercury-polluted paddy soil

Hualing Hu; Meng Li; Guoxi Wang; Marios Drosos; Zhen Li; Zhengyi Hu; Beidou Xi

doi:10.1016/j.chemosphere.2019.124405

Water-soluble mercury induced by organic amendments affected microbial community assemblage in mercury-polluted paddy soil

Chemosphere. 2019 Dec:236:124405. doi: 10.1016/j.chemosphere.2019.124405. Epub 2019 Jul 19.

Authors

Hualing Hu¹, Meng Li², Guoxi Wang³, Marios Drosos⁴, Zhen Li⁵, Zhengyi Hu³, Beidou Xi⁶

Affiliations

¹ College of Environmental Science and Engineering, Tianjin University, Tianjin, 300035, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
² State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: limeng12b@mails.ucas.ac.cn.
³ Sino-Danish College, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
⁴ Institute of Resource, Ecosystem and Environment of Agriculture, Faculty of Biology and Environment, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China.
⁵ Department of Soil Pollution and Control, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
⁶ College of Environmental Science and Engineering, Tianjin University, Tianjin, 300035, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: xibeidou@263.net.

PMID: 31545202
DOI: 10.1016/j.chemosphere.2019.124405

Abstract

Mercury (Hg) pollution or organic amendments (OA) may individually induce changes in the microbial community of paddy soils. However, little is known regarding the interaction of Hg and OA and the effect of different OA applications on the microbial community assemblage in Hg-polluted paddy soil. A soil incubation experiment was performed by applying three organic amendments (OA), namely a food-waste compost (FC), and its HA and FA, into an Hg-polluted paddy soil to examine the changes in the microbial community and merA/merB gene abundance. The results showed that the OA treatments promoted total (SOC) and dissolved organic carbon (DOC) in soils, which may harbor copiotrophic bacteria. The HA and FA treatments decreased microbial diversity and richness along with an increase of water-soluble Hg (WHg) through the complexation of DOC to Hg, which may be mainly attributed to the enhanced Hg biotoxicity to soil microbiome induced by the increased WHg under these two treatments. Additionally, the WHg enhancement also contributed to the increase of Hg-resistant bacteria and merA/merB gene abundance, and consequently, induced changes in the microbial community. These results indicated the interaction of Hg and different OA induced the variation of WHg fraction in paddy soil, which played a fundamental role in the distinct responses of the microbial community assemblage. Collectively, the application of FA and HA to Hg-polluted soil should be limited considering Hg risk to microbiome, and FC can be an alternative.

Keywords: 16S rRNA genes sequencing; Mercury (Hg); Mercury toxicity; Organic fertilizers; merA/merB gene.

MeSH terms

Bacteria / drug effects
Bacteria / genetics
Carbon / analysis
Fertilizers
Genes, Bacterial
Hydrogen-Ion Concentration
Mercury / analysis
Mercury / toxicity*
Microbiota / drug effects
Microbiota / genetics
Microbiota / physiology
Nitrogen / analysis
Soil / chemistry*
Soil Microbiology*
Soil Pollutants / analysis
Soil Pollutants / toxicity*
Solubility

Substances

Fertilizers
Soil
Soil Pollutants
Carbon
Mercury
Nitrogen