Lockwood, CL, Mortimer, RJG, Stewart, DI orcid.org/0000-0001-5144-1234 et al. (7 more authors) (2014) Mobilisation of arsenic from bauxite residue (red mud) affected soils: Effect of pH and redox conditions. Applied Geochemistry, 51. pp. 268-277. ISSN 0883-2927
Abstract
The tailings dam breach at the Ajka alumina plant, western Hungary in 2010 introduced ∼1 million m3 of red mud suspension into the surrounding area. Red mud (fine fraction bauxite residue) has a characteristically alkaline pH and contains several potentially toxic elements, including arsenic. Aerobic and anaerobic batch experiments were prepared using soils from near Ajka in order to investigate the effects of red mud addition on soil biogeochemistry and arsenic mobility in soil–water experiments representative of land affected by the red mud spill. XAS analysis showed that As was present in the red mud as As(V) in the form of arsenate. The remobilisation of red mud associated arsenate was highly pH dependent and the addition of phosphate to red mud suspensions greatly enhanced As release to solution. In aerobic batch experiments, where red mud was mixed with soils, As release to solution was highly dependent on pH. Carbonation of these alkaline solutions by dissolution of atmospheric CO2 reduced pH, which resulted in a decrease of aqueous As concentrations over time. However, this did not result in complete removal of aqueous As in any of the experiments. Carbonation did not occur in anaerobic experiments and pH remained high. Aqueous As concentrations initially increased in all the anaerobic red mud amended experiments, and then remained relatively constant as the systems became more reducing, both XANES and HPLC–ICP-MS showed that no As reduction processes occurred and that only As(V) species were present. These experiments show that there is the potential for increased As mobility in soil–water systems affected by red mud addition under both aerobic and anaerobic conditions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/3.0/). |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Civil Engineering (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 22 Jan 2015 15:46 |
Last Modified: | 26 Oct 2020 17:11 |
Published Version: | http://dx.doi.org/10.1016/j.apgeochem.2014.10.009 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.apgeochem.2014.10.009 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:82355 |