- Title
- Arsenic mobilization during seawater inundation of acid sulfate soils - Hydrogeochemical coupling at the tidal fringe
- Creator
- Johnston, Scott; Burton, Edward; Keene, Annabelle; Bush, Richard; Sullivan, Leigh
- Date
- 2012
- Type
- Text; Conference proceedings
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/99593
- Identifier
- vital:10389
- Abstract
- Coastal Acid Sulfate Soils (CASS) are rich in meta-stable iron (Fe - III) minerals that are important sorbents for arsenic (As) under oxic conditions. Tidal seawater inundation to remediate CASS has recently been trialed on a large scale and has potential to mobilize arsenic during the redox transition. Tidal seawater inundation caused reductive dissolution of As(V)-bearing Fe(III) minerals, resulting in elevated concentrations of Fe 2+ (2000 mg L -1) and As (∼400 μg L -1) in upper-intertidal zone groundwater. Oscillating vertical and horizontal hydraulic gradients caused by tidal pumping promoted upward advection of As and Fe 2+-enriched groundwater within the intertidal zone. This led to flux of As aq and Fe 2+ aq to surface waters and the accumulation of As(V)-enriched Fe(III) (hydr)oxides at the oxic sediment-water interface. Fe(III) (hydr)oxides at the sediment-water interface act as a natural reactive-barrier, retarding As flux to overlying surface waters. However, they also represent a highly transient phase that is prone to reductive dissolution during future redox boundary migration. A conceptual model is presented to explain landscape-scale patterns of As and Fe hydro-geochemical zonation. © 2012 Taylor & Francis Group.
- Publisher
- CRC Press, an imprint of Taylor & Francis
- Rights
- Copyright © 2012 Taylor & Francis Group.
- Rights
- This metadata is freely available under a CCO license
- Subject
- Acid sulfate soils; Arsenic mobilization; Boundary migration; Conceptual model; Elevated concentrations; Horizontal hydraulic gradient; Hydrogeochemical; Intertidal zones; Meta-stable; Oxic conditions; Redox transition; Reductive dissolution; Sediment water interface; Tidal pumping; Transient phase; Upward advection
- Hits: 1595
- Visitors: 1560
- Downloads: 0
| Thumbnail | File | Description | Size | Format |
|---|