Division of Agricultural Chemistry, Taiwan Agricultural Research Institute, Taichung City 41362, Taiwan.
Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan.
Environ Pollut. 2020 Nov;266(Pt 2):115140. doi: 10.1016/j.envpol.2020.115140. Epub 2020 Jul 4.
Water management such as drainage for creating aerobic conditions is considered to be an adequate method for reducing the accumulation of arsenic (As) in rice grains; however, it is difficult to conduct drainage operations in some areas that experience a lengthy rainy season as well as in soils with poor drainage. In this regard, application of oxygen-releasing compounds (ORCs) may be an alternative method for maintaining aerobic conditions even under flooding in paddy soils. Therefore, a pot experiment was conducted to investigate the effects of application of an ORC, calcium peroxide (CaO), on the growth and accumulation of As in rice plants grown in As-contaminated paddy soils. The rice plants were grown in two soils with different characteristics and As levels, and all of the tested soils were treated with 0, 5, 10, and 20 g CaO kg. Results revealed that the concentration of As and the distribution of arsenite in the pore water of all tested soils was reduced by CaO application. In addition, the grain yields increased and the concentration of inorganic As in brown rice decreased by 25-45% upon CaO treatment of low-As-level soils (<16 mg kg). However, the effect of CaO application on the accumulation of inorganic As in brown rice in As-enriched soils (>78 mg kg) could not found in this study, due to the rice plant suffered from serious As phytotoxicity. It suggests that CaO amendment may be suitable for reducing the As concentration of rice grains grown in low-As-level paddy soils, but for As-enriched soils, the proposed CaO application method is not feasible.
水管理，如排水以创造有氧条件，被认为是减少水稻籽粒中砷（As）积累的一种有效方法；然而，在一些雨季较长且排水不良的地区，很难进行排水作业。在这方面，应用释氧化合物（ORC）可能是一种在稻田淹水条件下保持有氧条件的替代方法。因此，进行了一项盆栽试验，研究了释氧化合物过氧化钙（CaO）的应用对受 As 污染的稻田中水稻生长和 As 积累的影响。在两种具有不同特性和 As 水平的土壤中种植水稻植物，并对所有测试土壤分别用 0、5、10 和 20 g CaO kg 进行处理。结果表明，CaO 的应用降低了所有测试土壤中 As 的浓度和亚砷酸盐在孔隙水中的分布。此外，低 As 水平土壤（<16 mg kg）经 CaO 处理后，糙米的产量增加，无机 As 浓度降低了 25-45%。然而，在本研究中，没有发现 CaO 应用对富 As 土壤（>78 mg kg）中糙米中无机 As 积累的影响，因为水稻植物受到严重的 As 植物毒性。这表明，CaO 改良剂可能适用于降低低 As 水平稻田中水稻籽粒的 As 浓度，但对于富 As 土壤，所提出的 CaO 应用方法不可行。
