| Project/Area Number |
16510050
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Risk sciences of radiation/Chemicals
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
HANZAWA Yukiko Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, Researcher, 原子力基礎工学研究部門, 研究員 (30354856)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Antimony / Paddy Field / Redox / Mobility / Soil / Soil Water / Speciation / Adsorption |
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| Research Abstract |
In paddy fields, the cycle of flooded and non-flooded periods causes changes of redox states in soil and soil water. This work investigated the speciation and mobility of antimony in paddy soil, which are redox-sensitive, by both laboratory experiments and field observations.
[Laboratory Experiment] Dried paddy soil samples were immersed in Sb(III) or Sb(V)solutions under conditions where the soil surface was exposed to the air (non-flooded) and where the soil surface was covered by the antimony solution (flooded). After 7 days immersion, the total antimony concentrations and the speciation of Sb(III) and Sb(V) in the soil waters were evaluated by a HPLC-ICP-MS system. As a result, in the non-flooded condition, the distribution ratio of antimony adsorption to soil obtained in the experiment using Sb(III) solution was lower than in the flooded condition and close to the value obtained in the experiment using Sb(V) solution. Moreover, the ratio of Sb(V) concentration to the total Sb concentration in the soil water was larger in the non-flooded condition than in the flooded condition. Then it was suggested that the oxidation of Sb(III) to Sb(V) would be promoted in the non-flooded condition.
[Field Observation] Soil water was collected at a paddy field in July 2005 (flooded condition). It was shown that the concentration of Sb(V) controlled the total concentration of Sb in the soil water.
The results of this work suggests a scenario as follows :
In summer (flooded period), antimony (e.g.originated in airborne particulate matter) would be accumulated in paddy soil.
In winter (non-flooded period), oxidation of the accumulated antimony in soil would be promoted and the mobility of antimony in soil would increase because of lower adsorption of Sb(V) to soil.
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