Microbial Sulfate Reduction Enhances Arsenic Mobility Downstream of Zerovalent-Iron-Based Permeable Reactive Barrier.

We assessed the potential of zerovalent-iron- (Fe(0)) based permeable reactive barrier (PRB) systems for arsenic (As) remediation in the presence or absence of microbial sulfate reduction. We conducted long-term (200 day) flow-through column experiments to investigate the mechanisms of As transformation and mobility in aquifer sediment (in particular, the PRB downstream linkage). Changes in As speciation in the aqueous phase were monitored continuously. Speciation in the solid phase was determined at the end of the experiment using X-ray absorption near-edge structure (XANES) spectroscopy analysis. We identified thio-As species in solution and AsS in solid phase, which suggests that the As(V) was reduced to As(III) and precipitated as AsS under sulfate-reducing conditions and remained as As(V) under abiotic conditions, even with low redox potential and high Fe(II) content (4.5 mM). Our results suggest that the microbial sulfate reduction plays a key role in the mobilization of As from Fe-rich aquifer sediment under anoxic conditions. Furthermore, they illustrate that the upstream-downstream linkage of PRB affects the speciation and mobility of As in downstream aquifer sediment, where up to 47% of total As initially present in the sediment was leached out in the form of mobile thio-As species.

[1]  G. Helz,et al.  Antimony speciation in alkaline sulfide solutions: role of zerovalent sulfur. , 2002, Environmental science & technology.

[2]  D. Parry,et al.  Removal of sulfate and heavy metals by sulfate reducing bacteria in short-term bench scale upflow anaerobic packed bed reactor runs. , 2003, Water research.

[3]  C. Mikutta,et al.  Sulfidization of Organic Freshwater Flocs from a Minerotrophic Peatland: Speciation Changes of Iron, Sulfur, and Arsenic. , 2016, Environmental science & technology.

[4]  E. Welter,et al.  Removal of arsenic from groundwater by zerovalent iron and the role of sulfide. , 2005, Environmental science & technology.

[5]  B. Mailloux,et al.  Microbes enhance mobility of arsenic in pleistocene aquifer sand from Bangladesh. , 2011, Environmental science & technology.

[6]  R. Bush,et al.  Microbial sulfidogenesis in ferrihydrite-rich environments: Effects on iron mineralogy and arsenic mobility , 2011 .

[7]  B. Merkel,et al.  Discrimination of thioarsenites and thioarsenates by X-ray absorption spectroscopy. , 2009, Analytical chemistry.

[8]  R. Oremland,et al.  Anaerobic Chemolithotrophic Growth of the Haloalkaliphilic Bacterium Strain MLMS-1 by Disproportionation of Monothioarsenate. , 2015, Environmental science & technology.

[9]  R. Root,et al.  The influence of sulfur and iron on dissolved arsenic concentrations in the shallow subsurface under changing redox conditions. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[10]  R. Wilkin,et al.  Formation of ferrihydrite and associated iron corrosion products in permeable reactive barriers of zero-valent iron. , 2002, Environmental science & technology.

[11]  J. Hollibaugh,et al.  A new role for sulfur in arsenic cycling. , 2008, Environmental science & technology.

[12]  R. Oremland,et al.  The Ecology of Arsenic , 2003 .

[13]  R. Couture,et al.  On-off mobilization of contaminants in soils during redox oscillations. , 2015, Environmental science & technology.

[14]  J. Rose,et al.  Sorption of arsenite, arsenate, and thioarsenates to iron oxides and iron sulfides: a kinetic and spectroscopic investigation. , 2013, Environmental science & technology.

[15]  D. Nordstrom.  Worldwide Occurrences of Arsenic in Ground Water , 2002, Science.

[16]  B. Planer-Friedrich,et al.  Stabilization of thioarsenates in iron-rich waters. , 2011, Chemosphere.

[17]  Mélanie Auffan,et al.  Molecular insights of oxidation process of iron nanoparticles: spectroscopic, magnetic, and microscopic evidence. , 2014, Environmental science & technology.

[18]  T. Borch,et al.  Arsenic repartitioning during biogenic sulfidization and transformation of ferrihydrite. , 2010 .

[19]  J. Drever,et al.  Precipitation of arsenic during bacterial sulfate reduction , 1995 .

[20]  R. Oremland,et al.  Bacterial respiration of arsenic and selenium. , 1999, FEMS microbiology reviews.

[21]  R. Pattrick,et al.  A study of speciation of Sb in bisulfide solutions by X-ray absorption spectroscopy , 2000 .

[22]  B. Kocar,et al.  Thermodynamic constraints on reductive reactions influencing the biogeochemistry of arsenic in soils and sediments. , 2009, Environmental science & technology.

[23]  M. Conklin,et al.  Electrochemical and spectroscopic study of arsenate removal from water using zero-valent iron media. , 2001, Environmental science & technology.

[24]  S. Benner,et al.  Arsenic release metabolically limited to permanently water-saturated soil in Mekong Delta , 2016 .

[25]  Charles F. Harvey,et al.  Arsenic Mobility and Groundwater Extraction in Bangladesh , 2002, Science.

[26]  Debashis Chatterjee,et al.  Role of metal-reducing bacteria in arsenic release from Bengal delta sediments , 2004, Nature.

[27]  R. Wilkin,et al.  Speciation of arsenic in sulfidic waters , 2003, Geochemical transactions.

[28]  Andreas C Scheinost,et al.  Arsenic speciation in sulfidic waters: reconciling contradictory spectroscopic and chromatographic evidence. , 2010, Analytical chemistry.

[29]  S. Coulon,et al.  Precipitation of arsenic sulphide from acidic water in a fixed-film bioreactor. , 2012, Water research.

[30]  Heechul Choi,et al.  Removal of arsenic(III) from groundwater by nanoscale zero-valent iron. , 2005, Environmental science & technology.

[31]  Leen Bastiaens,et al.  Inhibition of sulfate reducing bacteria in aquifer sediment by iron nanoparticles. , 2014, Water research.

[32]  Leen Bastiaens,et al.  Synergistic effects of sulfate reducing bacteria and zero valent iron on zinc removal and stability in aquifer sediment , 2015 .

[33]  J. Rose,et al.  Arsenic binding to organic and inorganic sulfur species during microbial sulfate reduction: a sediment flow-through reactor experiment , 2013 .

[34]  D. Springael,et al.  Positive impact of microorganisms on the performance of laboratory-scale permeable reactive iron barriers. , 2008, Environmental science & technology.

[35]  B. Kocar,et al.  Arsenic mobility during flooding of contaminated soil: the effect of microbial sulfate reduction. , 2014, Environmental science & technology.

[36]  Lan Ling,et al.  Sequestration of Arsenate in Zero-Valent Iron Nanoparticles: Visualization of Intraparticle Reactions at Angstrom Resolution , 2014 .

[37]  R. Bush,et al.  Sulfate availability drives divergent evolution of arsenic speciation during microbially mediated reductive transformation of schwertmannite. , 2013, Environmental science & technology.

[38]  K. Williams,et al.  Thioarsenic species associated with increased arsenic release during biostimulated subsurface sulfate reduction. , 2014, Environmental science & technology.

[39]  D. Burghardt,et al.  Development of a reactive zone technology for simultaneous in situ immobilisation of radium and uranium , 2005 .

[40]  B. Planer-Friedrich,et al.  Coupling of arsenic mobility to sulfur transformations during microbial sulfate reduction in the presence and absence of humic acid , 2013 .

[41]  J. Morse,et al.  Chemical dynamics of sedimentary acid volatile sulfide. , 2004, Environmental science & technology.

[42]  J. Tossell,et al.  Thermodynamic model for arsenic speciation in sulfidic waters: A novel use of ab initio computations , 2008 .

[43]  Leen Bastiaens,et al.  Microbial and mineral evolution in zero valent iron-based permeable reactive barriers during long-term operations , 2016, Environmental Science and Pollution Research.

[44]  D. Janecky,et al.  A Raman spectroscopic study of arsenite and thioarsenite species in aqueous solution at 25°C , 2002, Geochemical transactions.

[45]  J. Chorover,et al.  Microscale speciation of arsenic and iron in ferric-based sorbents subjected to simulated landfill conditions. , 2013, Environmental science & technology.

[46]  Härtig Cornelia,et al.  Thioarsenate transformation by filamentous microbial mats thriving in an alkaline, sulfidic hot spring , 2012 .

[47]  P. Van Cappellen,et al.  Reassessing the role of sulfur geochemistry on arsenic speciation in reducing environments. , 2011, Journal of hazardous materials.

[48]  Leen Bastiaens,et al.  Sulfur and oxygen isotope tracing in zero valent iron based In situ remediation system for metal contaminants. , 2013, Chemosphere.

[49]  K. Williams,et al.  Arsenic geochemistry in a biostimulated aquifer: An aqueous speciation study , 2013, Environmental toxicology and chemistry.

[50]  E. Roden,et al.  Experimental analysis of arsenic precipitation during microbial sulfate and iron reduction in model aquifer sediment reactors , 2010 .

[51]  Ruben Kretzschmar,et al.  Impacts of Shewanella putrefaciens strain CN-32 cells and extracellular polymeric substances on the sorption of As(V) and As(III) on Fe(III)-(hydr)oxides. , 2011, Environmental science & technology.

[52]  Fenglian Fu,et al.  The use of zero-valent iron for groundwater remediation and wastewater treatment: a review. , 2014, Journal of hazardous materials.

[53]  T. Onstott,et al.  Precipitation of Arsenic under Sulfate Reducing Conditions and Subsequent Leaching Under Aerobic Conditions , 2011 .

[54]  Michelle Sergent,et al.  Assessment of potential positive effects of nZVI surface modification and concentration levels on TCE dechlorination in the presence of competing strong oxidants, using an experimental design. , 2014, The Science of the total environment.

[55]  T. Phelps,et al.  Biogeochemical dynamics in zero-valent iron columns: Implications for permeable reactive barriers , 1999 .

[56]  P. Smedley,et al.  A review of the source, behaviour and distribution of arsenic in natural waters , 2002 .

[57]  Johnnie N. Moore,et al.  Partitioning of arsenic and metals in reducing sulfidic sediments , 1988 .

[58]  M. Stute,et al.  Laboratory investigations of enhanced sulfate reduction as a groundwater arsenic remediation strategy. , 2007, Environmental science & technology.

[59]  Michael Sampson,et al.  Integrated biogeochemical and hydrologic processes driving arsenic release from shallow sediments to groundwaters of the Mekong delta , 2008 .

[60]  Gregory V. Lowry,et al.  Chemical transformations during aging of zerovalent iron nanoparticles in the presence of common groundwater dissolved constituents. , 2010, Environmental science & technology.

[61]  R. Jakobsen,et al.  Release of arsenic associated with the reduction and transformation of iron oxides , 2006 .

[62]  L. Liang,et al.  Reductive precipitation of uranium(VI) by zero-valent iron , 1998 .