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

• DOI: 10.1021/acs.est.6b00128
• Publication Date: 2016-06-16T20:30:06Z
• Authors: Naresh Kumar; Raoul-Marie Couture; Romain Millot; Fabienne Battagli...; Jérôme Rose
• Keywords: Zerovalent iron; Permeable reactive barrier

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