Journal article
Diffusive gradients in thin films reveals differences in antimony and arsenic mobility in a contaminated wetland sediment during an oxic-anoxic transition
Environmental Science & Technology, Vol.52(3), pp.1118-1127
2018
PMID: 29303570
Metrics
29 Record Views
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Source: InCites
Abstract
Antimony (Sb) and arsenic (As) are priority environmental contaminants that often co-occur at mining-impacted sites. Despite their chemical similarities, Sb mobility in waterlogged sediments is poorly understood in comparison to As, particularly across the sediment–water interface (SWI) where changes can occur at the millimeter scale. Combined diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques provided a high resolution, in situ comparison between Sb, As, and iron (Fe) speciation and mobility across the SWI in contaminated freshwater wetland sediment mesocosms under an oxic–anoxic–oxic transition. The shift to anoxic conditions released Fe(II), As(III), and As(V) from the sediment to the water column, consistent with As release being coupled to the reductive dissolution of iron(III) (hydr)oxides. Conversely, Sb(III) and Sb(V) effluxed to the water column under oxic conditions and fluxed into the sediment under anoxic conditions. Porewater DGT–DET depth profiles showed apparent decoupling between Fe(II) and Sb release, as Sb was primarily mobilized across the SWI under oxic conditions. Solid-phase X-ray absorption spectroscopy (XAS) revealed the presence of an Sb(III)-S phase in the sediment that increased in proportion with depth and the transition from oxic to anoxic conditions. The results of this study showed that Sb mobilization was decoupled from the Fe cycle and was, therefore, more likely linked to sulfur and/or organic carbon (e.g., most likely authigenic antimony sulfide formation or Sb(III) complexation by reduced organic sulfur functional groups).
Details
- Title
- Diffusive gradients in thin films reveals differences in antimony and arsenic mobility in a contaminated wetland sediment during an oxic-anoxic transition
- Creators
- Maja Arsic - Griffith UniversityPeter R Teasdale - University of South AustraliaDavid T Welsh - Griffith UniversityScott G Johnston - Southern Cross UniversityEdward D Burton - Southern Cross UniversityKerstin Hockmann - Southern Cross UniversityWilliam W Bennett (Corresponding Author) - Southern Cross University
- Publication Details
- Environmental Science & Technology, Vol.52(3), pp.1118-1127
- Publisher
- American Chemical Society
- Identifiers
- 991012851498202368
- Academic Unit
- Faculty of Science and Engineering; National Centre for Flood Research; School of Environment, Science and Engineering; Southern Cross GeoScience; Science
- Language
- English
- Resource Type
- Journal article