Yuan, Zhao-Feng, Gustave, Williamson, Boyle, John 
ORCID: 0000-0002-1172-1079, Sekar, Raju ORCID: 0000-0002-1182-9004, Bridge, Jonathan, Ren, Yuxiang, Tang, Xianjin, Guo, Bin and Chen, Zheng
(2021)
Arsenic behavior across soil-water interfaces in paddy soils: Coupling, decoupling and speciation.
CHEMOSPHERE, 269.
128713-.
Abstract
The sharp redox gradient at soil-water interfaces (SWI) plays a key role in controlling arsenic (As) translocation and transformation in paddy soils. When Eh drops, As is released to porewater from solid iron (Fe) and manganese (Mn) minerals and reduced to arsenite. However, the coupling or decoupling processes operating within the redox gradient at the SWI in flooded paddy soils remain poorly constrained due to the lack of direct evidence. In this paper, we reported the mm-scale mapping of Fe, As and other associated elements across the redox gradient in the SWI of five different paddy soils. The results showed a strong positive linear relationship between dissolved Fe, Mn, As, and phosphorus (P) in 4 out of the 5 paddy soils, indicating the general coupling of these elements. However, decoupling of Fe, Mn and As was observed in one of the paddy soils. In this soil, distinct releasing profiles of Mn, As and Fe were observed, and the releasing order followed the redox ladder. Further investigation of As species showed the ratio of arsenite to total As dropped from 100% to 75.5% and then kept stable along depth of the soil profile, which indicates a dynamic equilibrium between arsenite oxidization and arsenate reduction. This study provides direct evidence of multi-elements' interaction along redox gradient of SWI in paddy soils.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Arsenic, Iron, Profile, Paddy soil, Coupling, Decoupling |
| Divisions: | Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology Faculty of Science and Engineering > School of Environmental Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 07 Jul 2021 10:09 |
| Last Modified: | 18 Jan 2023 21:36 |
| DOI: | 10.1016/j.chemosphere.2020.128713 |
| Open Access URL: | http://shura.shu.ac.uk/27526/ |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3129117 |
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