- Title
- Mobility of arsenic and selected metals during re-flooding of iron- and organic-rich acid-sulfate soil
- Creator
- Burton, Edward; Bush, Richard; Sullivan, Leigh; Johnston, Scott; Hocking, Rosalie
- Date
- 2008
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/99508
- Identifier
- vital:10375
- Identifier
-
https://doi.org/10.1016/j.chemgeo.2008.04.006
- Identifier
- ISSN:0009-2541
- Abstract
- The drainage-induced oxidation of iron-sulfide minerals in acid-sulfate soils has adversely affected large areas of coastal floodplains. Re-flooding of these soils, via the re-establishment of more natural drainage regimes, is a potential remediation approach. Here we describe the mobility of Al, As, Fe, Mn, Ni and Zn during controlled re-flooding of an Fe- and organic-rich acid-sulfate soil material. Soil re-flooding caused the onset of microbially-mediated Fe(III)-reduction, which raised the pH of the initially acidic (pH 3.4) soil to pH 6.0 to 6.5, thereby immobilizing Al. The process of Fe(III)-reduction released high concentrations of FeII and was associated with significant mobilization of As. During the early stages of re-flooding, FeII mobility was controlled by dissolution of schwertmannite (Fe8O8(OH)6SO4) with an ion activity product (IAP) of 1019 ± 2. The mobility of FeII was subsequently controlled by the precipitation of siderite (FeCO3) with an IAP spanning 10- 10 to 10- 7.5. The formation of acid-volatile sulfide (AVS), as a product of SO4-reduction, further retarded the mobility of FeII. Interactions with AVS also strongly immobilized Mn, Ni and Zn, yet had little effect on As which remained relatively mobile in the re-flooded soil. This study shows that the mobilization of As and Fe during soil re-flooding should be considered when planning remediation approaches for acid-sulfate soils. © 2008 Elsevier B.V. All rights reserved.
- Publisher
- Elsevier
- Relation
- Chemical Geology Vol. 253, no. 1-2 (2008), p. 64-73
- Rights
- Copyright © 2008 Elsevier B.V. All rights reserved.
- Rights
- This metadata is freely available under a CCO license
- Subject
- 0402 Geochemistry; 0403 Geology; 0406 Physical Geography and Environmental Geoscience; Acid volatile sulfide; Acid-sulfate soil; Arsenic; Heavy metals; Schwertmannite; Wetlands
- Reviewed
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