Journal article
Speciation and mobility of antimony and arsenic in a highly contaminated freshwater system and the influence of extreme drought conditions
Environmental Chemistry, Vol.18(7), pp.321-333
22/12/2021
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Abstract
Aqueous and solid-state antimony (Sb) and arsenic (As) speciation is assessed in an Australian freshwater system contaminated by mining of primary sulfide minerals. The study aims to understand metalloid transformation and mobilisation in the system, and coincides with a severe drought providing the opportunity to examine the influence of extreme low-flow conditions. X-ray absorption spectra identified only SbV in <2 mm sediments, despite boulder size stibnite evident in the creek. Roméite-group minerals were detected by X-ray diffraction in oxidation rims of creek-bed stibnite, which potentially limit the contribution of dissolved SbIII to the waterway. Arsenic in <2 mm sediments was dominated by AsV (17–91 %) and orpiment (16–93 %), while the co-occurrence of AsIII (11–36 %) with orpiment suggests that primary As minerals are an important ongoing source of AsIII to the system. Dissolved metalloids (<45 µm filtered) dominated total water column concentrations and comprised mainly pentavalent species. Arsenic(III) was however identified in most water samples (up to 6.6 µg L−1), while dissolved SbIII was only detected in one sample (3.4 µg L−1) collected during the drought period. Dissolved AsV increased significantly in samples collected in low-flow conditions, considered a result of reductive dissolution of sediment Fe-oxyhydroxide host phases, but a similar increase in dissolved Sb was not observed. This study highlights a greater risk from As in this system, and the likelihood of increased As mobility under the warmer and drier environmental conditions predicted with climate change, especially during first-flush events.
Details
- Title
- Speciation and mobility of antimony and arsenic in a highly contaminated freshwater system and the influence of extreme drought conditions
- Creators
- Steven Doherty - University of New EnglandMatthew K Tighe - University of New EnglandLuke A Milan - University of New EnglandLeanne Lisle - University of New EnglandCalvin Leech - University of New EnglandBernt Johannessen - Australian SynchrotronValerie Mitchell - Australian SynchrotronJessica Hamilton - Australian SynchrotronScott G Johnston - Southern Cross UniversitySusan C Wilson - University of New England
- Publication Details
- Environmental Chemistry, Vol.18(7), pp.321-333
- Publisher
- CSIRO
- Grant note
- The study was undertaken with the assistance of a Research Training Program scholarship provided by the Australian Commonwealth Government. Antimony and arsenic X-ray absorption spectra were collected at the XAS beamline of the Australian Synchrotron, Clayton, Victoria (grant numbers AS192/XAS/14670 and AS1/XAS/15662). Salary support for Steven Doherty was provided by the Department of Regional NSW and UNE during writing of this manuscript.
- Identifiers
- 991012987889802368
- Copyright
- Journal compilation © CSIRO 2021
- Academic Unit
- Science; Southern Cross GeoScience; Faculty of Science and Engineering
- Language
- English
- Resource Type
- Journal article