Iron monosulfide formation and oxidation in drain-bottom sediments of an acid sulfate soil environment |
| |
| Institution: | 1. School of Civil Engineering, Chongqing University, Chongqing, PR China;2. Key Laboratory of New Technology of Construction of Cities in Mountain Area, Chongqing University, Ministry of Education, Chongqing 400045, PR China;3. Utah State University, Logan, UT 84322-4130, USA;1. Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, USA;2. Department of Civil and Environmental Engineering, University of Michigan, USA;1. Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), UMR 7590 CNRS-Sorbonne Université-IRD-MNHN, case 115, 4 place Jussieu, 75252 Paris Cedex 5, France;2. Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France;3. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 69, Menlo Park, CA 94025, USA;4. Géosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPS, CNES, 14, Avenue Edouard Belin, 31400 Toulouse, France;5. Institut de Recherche pour le Développement (IRD), UMR 206/UMR 7590 IMPMC, 98848 Nouméa, New Caledonia |
| |
| Abstract: | Iron monosulfide formation and oxidation processes were studied in the extensively drained acid sulfate soil environment of the Tweed River floodplain in eastern Australia. Porewater profiles of pH, Eh, SO42?, Fe2+, Fe3+, Cl?, HCO3?, and metals (Cd, Co, Cr, Cu, Ni, Pb and Zn) were obtained using in situ dialysis membrane samplers (`peepers'). Concentrations of acid volatile S (AVS), pyrite, total S, reactive Fe, total and organic C, simultaneously extracted metals (SEMs) and total elemental composition by X-ray fluorescence, were determined on sediment samples. The oxidation of pyrite in the surrounding landscape provides a source of acidity, Fe, Al, SO4 and metals, which are exported into the drainage system where they accumulate in the sediments and porewaters. Negative porewater concentration gradients of SO42? and Fe2+, and large AVS concentrations in the sediments, indicate Fe monosulfides form rapidly under reducing conditions and consume acidity and metals. Oxidation of the sediments during previous drought episodes has resulted in the conversion of monosulfides and pyrite to oxidised Fe minerals and the release of acidity, SO42?, Fe3+, and metals to the surface waters. These formation and oxidation cycles show that Fe monosulfides play an important role in controlling water quality in the drainage system. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
