Department of Environmental Engineering and Soil Environment Research Center, Jeonbuk National University, Jeonju, Jeollabukdo 57896, Republic of Korea.
Department of Environmental Engineering and Soil Environment Research Center, Jeonbuk National University, Jeonju, Jeollabukdo 57896, Republic of Korea; Department of Environment & Energy and Soil Environment Research Center, Jeonbuk National University, Jeonju, Jeollabukdo 57896, Republic of Korea.
Sci Total Environ. 2021 Mar 25;762:143124. doi: 10.1016/j.scitotenv.2020.143124. Epub 2020 Oct 17.
Arsenic (As) is uptaken more readily by rice over wheat and barley. The exposure of As to humans being in the rice-consuming regions is a serious issue. Thus, an effective practice to reduce the translocation of As from soil to rice grain should be implemented. During a flooding period, the water layer greatly limits the transport of oxygen from atmosphere to soil, which provides favorable conditions for reduction of oxygen. The reduction of Fe in the soil during the flooding condition is closely related to the As mobility, which expedites the release of As to the soil pore solution and increases As uptake by rice plants. Therefore, the performance of oxygen releasing compounds (ORCs) was evaluated to lower the translocation of As from soil to soil solution. Specifically, in the simple system containing ORCs and water, the oxygen releasing capacity of ORCs was scrutinized. In addition, ORCs was applied to sea sand and arsenic bearing ferrihydrite to identify the contribution of ORCs to As and iron mobility. Especially, ORCs were introduced to the closed (completely mixed system) and open (static) systems to simulate the paddy soil environment. Introducing ORCs increased the DO in the aqueous phase, and CaO was more effective in increasing DO than MgO. In the static system simulating a rice field, the dissolution of ORCs was inhibited. The pH increased due to the formation of hydroxide, but the increase was not significant in the soil due to the buffering capacity of the soil. Finally, the As concentration in the soil solution was lowered to 25-50% of that of the control system by application of ORCs in the static paddy soil system. All experimental findings signify that the application of ORCs can be an effective practice to lower the translocation of As from soil to pore solution.
砷（As）在水稻中比在小麦和大麦中更容易被吸收。在食用大米的地区，人类接触砷是一个严重的问题。因此，应该采取有效的措施来减少砷从土壤向稻谷中的转移。在淹水期间，水层极大地限制了氧气从大气向土壤的传输，这为还原作用提供了有利条件。在淹水条件下，土壤中铁的还原与砷的迁移性密切相关，这加速了砷向土壤孔隙溶液的释放，并增加了水稻对砷的吸收。因此，评估了释氧化合物（ORC）的性能，以降低砷从土壤向土壤溶液的迁移。具体而言，在含有 ORC 和水的简单体系中，研究了 ORC 的释氧能力。此外，将 ORC 应用于海砂和含砷的水铁矿，以确定 ORC 对砷和铁迁移性的贡献。特别是，将 ORC 引入封闭（完全混合系统）和开放（静态）系统，以模拟稻田环境。引入 ORC 增加了水相中的 DO，而 CaO 比 MgO 更有效地增加 DO。在模拟稻田的静态系统中，ORC 的溶解受到抑制。由于形成了氢氧化物，pH 值有所增加，但由于土壤的缓冲能力，土壤中的增加并不显著。最后，通过在静态稻田系统中应用 ORC，将土壤溶液中的砷浓度降低到对照系统的 25-50%。所有实验结果都表明，应用 ORC 可以有效地降低砷从土壤向孔隙溶液的迁移。
