Effect of the redox dynamics on microbial-mediated As transformation coupled with Fe and S in flow-through sediment columns.
Arsenic (As) biogeochemistry coupled with iron (Fe) and sulfur (S) was studied using columns packed with As(V)-contaminated sediments under two phases: a reduction phase followed by an oxidation phase. During the reduction phase, four identical columns inoculated with G. sulfurreducens were stimulated with 3mM acetate for 60days. The As(III) in the effluent rapidly increased then gradually decreased. The Fe(II) and sulfate concentration indicated ferrous sulfide precipitation inside the column after day 14 and X-ray absorption near edge structure spectra showed that As(III) was enriched at the column outlet. The genera Desulfosporosinus and Anaeromyxobacter as well as the Geobacter inoculum played a primary role in As reduction. During the oxidation phase, dissolved oxygen was consumed by heterotrophic aerobes belonging to the phylum Cloroflexi in the column with acetate, resulting in more As in the effluent. When only nitrate was injected, sulfur-oxidizing bacteria such as Thiobacillus thioparus instantly oxidized the sulfide formed during the first phase, resulting in less As(V) in the aqueous phase compared to the column with dissolved oxygen alone. This study showed that redox gradients and dynamics linked to Fe and S biogeochemistry have an important role in controlling As mobility in subsurface environments.
Groundwater Department, Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132, Republic of Korea; Department of Mineral and Groundwater Resources, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea. Electronic address: hmoon@kigam.re.kr.
Hee Sun
HS
Moon
Groundwater Department, Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132, Republic of Korea.
Bo-A
BA
Kim
Groundwater Department, Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132, Republic of Korea; Department of Mineral and Groundwater Resources, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea.
Sung Pil
SP
Hyun
Groundwater Department, Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132, Republic of Korea.
Yoon-Ho
YH
Lee
Unban Mine Department, Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 34132, Republic of Korea; Department of Resource Recycling Engineering, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea.
Doyun
D
Shin
D001151:Arsenic / Q000378:metabolism*; D001711:Biotransformation; D000068536:Bacillota / Q000378:metabolism; D045302:Geobacter / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D060587:Groundwater / Q000737:chemistry / Q000382:microbiology*; D007501:Iron / Q000378:metabolism*; D064307:Microbiota; D010084:Oxidation-Reduction; D013455:Sulfur / Q000378:metabolism*
D013455:Sulfur; D007501:Iron; D001151:Arsenic
Arsenic; Dissolved oxygen; Microbial community; Nitrate; Redox sequence