Optimal Soil Eh, pH, and Water Management for Simultaneously Minimizing Arsenic and Cadmium Concentrations in Rice Grains
Optimal Soil Eh, pH, and Water Management for Simultaneously Minimizing Arsenic and Cadmium Concentrations in Rice Grains
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DOI：
10.1021/acs.est.5b05424
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发表时间：
2016-04-19
影响因子：
11.4
通讯作者：
Katou, Hidetaka
中科院分区：
文献类型：
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作者：
Honma, Toshimitsu;Ohba, Hirotomo;Katou, Hidetaka
稻米中的砷（As）和镉（Cd）浓度是人类健康问题。通过田间试验，研究了土壤Eh和pH同时降低水稻As和Cd积累的最佳条件。试验中的水分管理，包括连续淹水和季中排水后不同时间间隔的间歇灌溉，通过改变土壤Eh、pH和溶解态Fe（II）浓度，对土壤溶解态As和Cd浓度产生显著影响。间歇灌溉与3天的洪水和5天的排水被认为是有效的，同时减少砷和镉在籽粒中的积累。籽粒中As和Cd含量分别与抽穗后3周内的平均溶解态As和Cd含量呈线性相关。我们提出了一个新的指标，用于表示在何种程度上减少溶解的As或Cd的浓度是由其他的增加妥协。为了最大限度地减少As和Cd在水稻籽粒中的权衡关系，水分管理策略的目标是在抽穗后3周内实现最佳土壤Eh为-73 mV和pH为6.2。
Arsenic (As) and cadmium (Cd) concentrations in rice grains are a human health concern. We conducted field experiments to investigate optimal conditions of Eh and pH in soil for simultaneously decreasing As and Cd accumulation in rice. Water managements in the experiments, which included continuous flooding and intermittent irrigation with different intervals after midseason drainage, exerted striking effects on the dissolved As and Cd concentrations in soil through changes in Eh, pH, and dissolved Fe(II) concentrations in the soil. Intermittent irrigation with three-day flooding and five-day drainage was found to be effective for simultaneously decreasing the accumulation of As and Cd in grain. The grain As and Cd concentrations were, respectively, linearly related to the average dissolved As and Cd concentrations during the 3 weeks after heading. We propose a new indicator for expressing the degree to which a decrease in the dissolved As or Cd concentration is compromised by the increase in the other. For minimizing the trade-off relationship between As and Cd in rice grains in the field investigated, water management strategies should target the realization of optimal soil Eh of -73 mV and pH of 6.2 during the 3 weeks after heading.