HR: 1340h
AN: B33A-0858    [Abstracts]
TI: Immobilization of Arsenic by Vivianite Biomineralization
AU: Kim, H
EM: 21eagle@naver.com
AF: School of Earth and Environmental Sciences, Seoul National University, San 56-1. Sillim- dong, Gwanak-gu, Seoul, 151-742, Korea, Republic of
AU: Park, B
AF: Faculty of Earth Systems and Environmental Sciences, Chonnam National University, 300 Yongbong-Dong, Buk-Gu, Gwangju, 500-757, Korea, Republic of
AU: Lee, I
AF: School of Earth and Environmental Sciences, Seoul National University, San 56-1. Sillim- dong, Gwanak-gu, Seoul, 151-742, Korea, Republic of
AU: * Roh, Y
EM: rohy@chonnam.ac.kr
AF: Faculty of Earth Systems and Environmental Sciences, Chonnam National University, 300 Yongbong-Dong, Buk-Gu, Gwangju, 500-757, Korea, Republic of
AB: Microbial metal reduction and biomineralization has the potential for immobilizing metals and radionuclides in subsurface environments. The objective of this study was to examine Fe reduction and biomineralization in the presence of arsenite or arsenate using metal-reducing bacteria, Shewanella sp. (Haejae-1), enriched from an intertidal flat sediment, South Korea. The bacteria was able to use glucose as an electron donor and Fe(III)-citrate as an electron acceptor in the presence of arsenite or arsenate using phosphate buffered saline medium. The reduction of Fe(III)-citrate in the presence of arsenite or arsenate resulted in the precipitation of white µm-sized crystalline minerals. XRD analysis of the white precipitate after 14-day incubation identified the mineral phase as vivianite. SEM with EDX analysis of the vivianite precipitated by the metal reducing bacteria confirmed the presence of Fe, As, O, and P. This study indicates that formation of sparingly soluble vivianite precipitates, mediated by the metal -reducing bacteria, may sequester iron, phosphate, and arsenic into more stable and less toxic forms. The formation of phosphate minerals has frequently been observed in sedimentary environments under high biological productivity, where organic matter serves as a source of phosphate to sediment pore water through bacterial degradation. Therefore, formation of sparingly soluble iron precipitates, mediated by the metal- reducing bacteria, may sequester iron, phosphate, and other metals into more stable and less toxic forms in subsurface environments.
DE: 0418 Bioremediation
DE: 0419 Biomineralization
DE: 0461 Metals
DE: 0463 Microbe/mineral interactions
DE: 0471 Oxidation/reduction reactions (4851)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting