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| Arsenic biogeochemical processing in the soil-rice system |
| Received:October 16, 2018 |
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| KeyWord:rice;arsenic;soil;silicate;iron cycle |
| Author Name | Affiliation | E-mail | | WU Chuan | School of Metallurgy and Environment, Central South University, Changsha 410083, China | | | AN Wen-hui | School of Metallurgy and Environment, Central South University, Changsha 410083, China | | | XUE Sheng-guo | School of Metallurgy and Environment, Central South University, Changsha 410083, China | sgxue70@hotmail.com | | JIANG Xing-xing | School of Metallurgy and Environment, Central South University, Changsha 410083, China | | | CUI Meng-qian | School of Metallurgy and Environment, Central South University, Changsha 410083, China | | | QIAN Zi-yan | School of Metallurgy and Environment, Central South University, Changsha 410083, China | |
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| Abstract: |
| Arsenic(As)contamination of paddy soils in south China has received increasing attention, as it has caused severe rice contamination and negatively affects the health of millions of people who rely on rice as a staple food. The As biogeochemical process in soil contributes critically in the control of As contamination. In this article, the mechanism of As uptake and translocation in the soil-plant system has been summarized. In addition, the effect of radial oxygen loss(ROL)of different rice genotypes on As fractionation in soil, Fe plaque formation, and As accumulation in rice and the effect of water management on As speciation in soil, As uptake, and expression of As transporters in rice have been systematically reviewed. Rice genotypes with high ROL formed extra Fe plaque on roots, which reduced As uptake in rice. Compared with continuous flooding, water management with intermittent flooding and aerobic soil conditions significantly reduced As uptake and accumulation in rice. Moreover, the effect of Si application to soil on As uptake in rice and related mechanisms were examined, with the Si/As ratio in soils the major factor controlling the As uptake in rice. In addition, the effect of Fe redox processes on As biogeochemical behaviors were studied. The microorganism-mediated Fe redox reaction had significant influence on As behaviors such as dissolution, release, adsorption, coprecipitation, and speciation. Moreover, the extracellular electron transfer process of Fe oxidation and reduction bacteria significantly impacted the transformation of Fe minerals and related As immobilization in soils, which deserves further attention in future research. |
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