title: Effects of microbially induced transformations and shift in bacterial community on arsenic mobility in arsenic-rich deep aquifer sediments.
abstract: Elevated concentration of arsenic (As) prevailed in deep aquifers of Chianan Plain, Taiwan. Arsenic release in relation to microbially induced transformations and shift in bacterial communities in deep aquifer sediments of Budai, southwestern Taiwan were investigated using microcosm experiments and substrate amendments over 90 days of anaerobic incubation. The results revealed that As reduction was independent of Fe reduction and a modest rate of sedimentary As release into aqueous phase occurred at the expense of the native organic carbon. Addition of lactate resulted in a parallel increase in As(III) (3.7-fold), Fe(II) (6.2-fold) and Mn (3.5 fold) in aqueous phase compared to un-amended slurries and the enrichment of sequences related to mostly Bacillus, Flavisolibacter, and Geobacter spp, suggesting the important role of these bacteria in As enrichment through reductive dissolution of As-bearing Fe and Mn minerals. The increase in phosphate-extractable As in solid phase with concomitant rise in As in aqueous phase over the course of incubation further attested to the importance of reductive dissolution in promoting As release. Furthermore, the increase in arrA gene abundance with addition of labile carbon suggests that dissimilatory As reduction also may contribute to As enrichment in the water of the deep aquifer of Budai.
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Suvendu
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Chia-Chuan
authors.initials: CC
authors.lastname: Liu
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan. Electronic address: jiinshuh@mail.ncku.edu.tw.
authors.forename: Jiin-Shuh
authors.initials: JS
authors.lastname: Jean
authors.affiliation: Molecular Diagnosis Laboratory, Department of Pathology, College of Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Chuan-Chun
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Huai-Jen
authors.initials: HJ
authors.lastname: Yang
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001711:Biotransformation; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D019015:Geologic Sediments / Q000032:analysis / Q000382:microbiology*; D060587:Groundwater; D007501:Iron / Q000032:analysis / Q000378:metabolism; D008345:Manganese / Q000032:analysis / Q000378:metabolism; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; D008345:Manganese; D007501:Iron; D001151:Arsenic
keywords: 454-pyrosequencing; Arsenic mobilization; Iron mobilization; Microbial transformations; Reductive dissolution