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The impact of oscillating redox conditions: arsenic immobilisation in contaminated calcareous floodplain soils.

Authors :
Parsons CT
Couture RM
Omoregie EO
Bardelli F
Greneche JM
Roman-Ross G
Charlet L
Source :
Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2013 Jul; Vol. 178, pp. 254-63. Date of Electronic Publication: 2013 Apr 13.
Publication Year :
2013

Abstract

Arsenic contamination of floodplain soils is extensive and additional fresh arsenic inputs to the pedosphere from human activities are ongoing. We investigate the cumulative effects of repetitive soil redox cycles, which occur naturally during flooding and draining, on a calcareous fluvisol, the native microbial community and arsenic mobility following a simulated contamination event. We show through bioreactor experiments, spectroscopic techniques and modelling that repetitive redox cycling can decrease arsenic mobility during reducing conditions by up to 45%. Phylogenetic and functional analyses of the microbial community indicate that iron cycling is a key driver of observed changes to solution chemistry. We discuss probable mechanisms responsible for the arsenic immobilisation observed in-situ. The proposed mechanisms include, decreased heterotrophic iron reduction due to the depletion of labile particulate organic matter (POM), increases to the proportion of co-precipitated vs. aqueous or sorbed arsenic with α-FeOOH/Fe(OH)3 and potential precipitation of amorphous ferric arsenate.<br /> (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Details

Language :
English
ISSN :
1873-6424
Volume :
178
Database :
MEDLINE
Journal :
Environmental pollution (Barking, Essex : 1987)
Publication Type :
Academic Journal
Accession number :
23587855
Full Text :
https://doi.org/10.1016/j.envpol.2013.02.028