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Biotic Arsenic Mobilization in Natural and Anthropogenic Systems from Redox Transformations of Arsenic, Iron and Sulfur

Stuckman, Mengling Yi
http://rave.ohiolink.edu/etdc/view?acc_num=osu1388505419

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Environmental Science.
The mobility of arsenic (As) is difficult to predict or determine in geological systems that have large spatial and temporal variations in biogeochemistry (e.g., redox, microbial communities and aqueous chemistry). To characterize As mobility under such conditions requires an understanding of As sorption behavior onto minerals, mineral-microbe interactions and microbially-driven As redox cycles, which can be gained through coupling detailed spectroscopy, microbiology and molecular biotechnology. In this study, two biotic arsenic mobilization investigations are detailed, one comprising processes in an engineered setting and the other in a natural system. In the first component of this study, microbially-mediated As release from spent drinking water adsorbents under simulated landfill conditions was evaluated using biotic incubations. Single cultures of microorganisms with different As, Fe and S reducing capabilities and growth medium amended by competitive anions were utilized in separate batch incubations to simulate landfills with geochemical and microbial variability. My results demonstrated that microbial As release was 100 times more significant than its abiotic control. Landfill conditions with high levels of phosphate and bicarbonate enhanced As bioreduction by solubilizing bioavailable As, resulting in significant As mobilization, which was further confirmed by thermodynamic calculations. Synchrotron-based micro-spectroscopy showed enhanced As co-precipitation with mackinawite (FeS) via sulfate reduction in S/P accumulated micro-scale hotspots. These results suggest screening tests to evaluate the environmental impact of As-containing solid waste disposal into landfills should consider microbial As release under simultaneous Fe and S reducing conditions, in particular when the landfill leachate contains high levels of phosphate and bicarbonate. The second component of this study entailed evaluating As release mechanisms under highly reduced groundwater conditions. Anaerobic incubations were conducted with groundwater containing indigenous microbes and sediments sampled at different depths from an aquifer in Ohio. Indigenous dissolved organic matter (DOM) and acetate were added at different periods of the incubation to characterize biogeochemical changes responsible for different As behavior in response to DOM introduction. Incubation studies revealed rapid geochemical changes in response to acetate, but not DOM. Besides reductive iron dissolution, the sulfidogenesis of iron minerals determined As mobility by forming different Fe(II)S(-II) minerals as confirmed by sequential solid phase extractions. For the deep, methanogenic aquifer solids, As was released 7 times higher than the current drinking water standards via bicarbonate exchange on the surface of the disordered mackinawite (FeS) from Fe-rich sulfidigenosis. In the shallower sulfate-reducing aquifer, As sequestration into crystalline pyrite (FeS2) from S-rich sulfidogenesis resulted in low detection of As in groundwater. 16S rRNA sequencing results detected an increase in biomarkers for iron and sulfate reducing bacterial communities in response to the addition of dissolved organic matter or acetate prior to aqueous geochemical changes. This second study identified the As release source (iron-rich FeS) in drinking water wells drilled at glacial till aquifers under methanogenic conditions and suggested the use of microbial biomarkers as a timely indicator of microbially-mediated As release in groundwater systems. Overall, my research demonstrates that understanding As release from highly variable geological systems requires an interdisciplinary research approach applying advanced spectroscopic technologies, aqueous and solid phase analyses and molecular biology techniques.
John Lenhart (Advisor)
Nicholas Basta (Committee Member)
Olli Tuovinen (Committee Member)
Brian Lower (Committee Member)
Kirk Scheckel (Committee Member)
306 p.
Environmental Engineering; Environmental Geology; Environmental Science
biogeochemistry, landfill, groundwater, sulfidization, methanogenesis, dissolved organic matter, mineral biotransformation, microbial community

Recommended Citations

Citations

  • Stuckman, M. Y. (2014). Biotic Arsenic Mobilization in Natural and Anthropogenic Systems from Redox Transformations of Arsenic, Iron and Sulfur [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388505419

    APA Style (7th edition)

  • Stuckman, Mengling. Biotic Arsenic Mobilization in Natural and Anthropogenic Systems from Redox Transformations of Arsenic, Iron and Sulfur. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1388505419.

    MLA Style (8th edition)

  • Stuckman, Mengling. "Biotic Arsenic Mobilization in Natural and Anthropogenic Systems from Redox Transformations of Arsenic, Iron and Sulfur." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388505419

    Chicago Manual of Style (17th edition)

osu1388505419
539
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This open access ETD is published by The Ohio State University and OhioLINK.
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