title: In Vitro Method To Assess Soil Arsenic Metabolism by Human Gut Microbiota: Arsenic Speciation and Distribution.
abstract: Arsenic (As) speciation and distribution are two important factors in assessing human health risk from As-contaminated soil. In this study, we used the combination of physiologically based extraction test (PBET) and Simulator of Human Intestinal Microbial Ecosystem (SHIME) to determine soil As metabolism by human gut microbiota. The results showed that the percentage of soil arsenate [As(V)] transformation reached 22.1-38.2%, while that of arsenite [As(III)] attained 66.5-92.0%; 30.1-56.4% of As(V) transformed was attached to the soil solid phase. In comparison to sequential extraction results, almost all amorphous Fe/Al-oxide-bound As was liberated in the colon phase. An X-ray absorption near-edge structure (XANES) showed that the As(III) percentage in the soil solid phase reached 16.6-26.9% and reached 73.4% (soil 1) in the colon phase. Additionally, plenty of As(III) and different extents of methylation were also observed in colon extraction solution. As bioaccessibility in the colon phase was 1.8-2.8 times that in the small intestinal phase. Our results indicated that human gut microbiota increased As bioaccessibility, and large amounts of As(III) were adsorbed onto the soil solid phase as a result of microbial reduction. Determining As speciation and distribution in extraction solution and soil solid phases will allow for an accurate assessment of the risk to human health upon soil As exposure.
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Naiyi
authors.initials: N
authors.lastname: Yin
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Zhennan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Cai
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Huili
authors.initials: H
authors.lastname: Du
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environment Sciences, Chinese Academy of Sciences , Beijing 100085, People's Republic of China.
authors.forename: Guoxin
authors.initials: G
authors.lastname: Sun
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
authors.forename: Yanshan
authors.initials: Y
authors.lastname: Cui
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D001682:Biological Availability; D003106:Colon / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods*; D000069196:Gastrointestinal Microbiome; D006801:Humans; D008745:Methylation; D012987:Soil / Q000737:chemistry*; D012996:Solutions; D056928:X-Ray Absorption Spectroscopy
chemical_list: D012987:Soil; D012996:Solutions; D001151:Arsenic