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首页> 外文期刊>Environmental Science & Technology >Arsenic Distribution and Speciation near Rice Roots Influenced by Iron Plaques and Redox Conditions of the Soil Matrix
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Arsenic Distribution and Speciation near Rice Roots Influenced by Iron Plaques and Redox Conditions of the Soil Matrix

机译：铁斑和土壤基质氧化还原条件对水稻根系附近砷分布和形态的影响

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摘要

Elevated arsenic (As) concentrations in rice and the soil solution result from changes in soil redox conditions, influenced by the water management practices during rice cultivation. Microscale changes in redox conditions from rhizosphere to soil matrix affect the As speciation and Fe plaque deposition. In order to focus on the rhizosphere environment, we observed microscale distribution and speciation of As around the rhizosphere of paddy rice with X-ray fluorescence mapping and X-ray absorption spectroscopy. When the soil matrix was anaerobic during rice growth, Fe-plaque did not cover the entire root, and As(Ⅲ) was the dominant arsenic species in the soil matrix and rhizosphere. Draining before harvest led the conditions to shift to aerobic. Oxidation of As(Ⅲ) to As(Ⅴ) occurred faster in the Fe-plaque than the soil matrix. Arsenic was scavenged by iron mottles originating from Fe-plaque around the roots. The ratio of As(Ⅴ) to As(Ⅲ) decreased toward the outer-rim of the subsurface Fe mottles where the soil matrix was not completely aerated. These results provide direct evidence that speciation of As near rice roots depends on spatial and temporal redox variations in the soil matrix.
机译：水稻和土壤溶液中砷（As）浓度升高是由于土壤氧化还原条件的变化所致，受稻米种植过程中水管理实践的影响。从根际到土壤基质的氧化还原条件的微小变化都会影响砷形态和铁斑沉积。为了关注根际环境，我们利用X射线荧光作图和X射线吸收光谱法观察了水稻根际周围砷的微观分布和形态。当水稻生长过程中土壤基质厌氧时，铁斑无法覆盖整个根部，As（Ⅲ）是土壤基质和根际中的主要砷种。收获前的排水导致条件转向有氧运动。 Fe-斑块中As（Ⅲ）氧化为As（Ⅴ）的速度比土壤基质快。砷被根周围的铁斑块中的铁斑清除。 As（Ⅴ）与As（Ⅲ）的比例朝着土壤基质未完全充气的地下Fe斑纹的外边缘降低。这些结果提供了直接的证据，表明水稻根部附近砷的形态取决于土壤基质中的时空氧化还原变化。

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  • 来源
    《Environmental Science & Technology》 |2014年第3期|1549-1556|共8页
  • 作者

    Noriko Yamaguchi; Toshiaki Ohkura; Yoshio Takahashi; Yuji Maejima; Tomohito Arao;

  • 作者单位

    National Institute for Agro-environmental Sciences, 3-1-3, Kan-nondai, Tsukuba, 305-8604, Japan;

    National Institute for Agro-environmental Sciences, 3-1-3, Kan-nondai, Tsukuba, 305-8604, Japan;

    Department of Earth and Planetary Systems Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan;

    National Institute for Agro-environmental Sciences, 3-1-3, Kan-nondai, Tsukuba, 305-8604, Japan;

    National Institute for Agro-environmental Sciences, 3-1-3, Kan-nondai, Tsukuba, 305-8604, Japan;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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