Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.
Environ Sci Technol. 2023 Aug 22;57(33):12280-12290. doi: 10.1021/acs.est.3c03205. Epub 2023 Aug 7.
Arsenic (As) is a major environmental pollutant and poses a significant health risk to humans through rice consumption. Elevating the soil redox potential (Eh) has been shown to reduce As bioavailability and decrease As accumulation in rice grains. However, sustainable methods for managing the Eh of rice paddies are lacking. To address this issue, we propose a new approach that uses man-made aerenchymatous tissues (MAT) to increase soil Eh by mimicking O release from wet plant roots. Our study demonstrated that the MAT method sustainably increased the soil Eh levels from -119 to -80.7 mV (∼30%), over approximately 100 days and within a radius of around 5 cm from the surface of the MAT. Moreover, it resulted in a significant reduction (-28.5% to -63.3%) in dissolved organic carbon, Fe, Mn, and As concentrations. MAT-induced Fe(III) (oxyhydr)oxide minerals served as additional adsorption sites for dissolved As in soil porewater. Furthermore, MAT promoted the oxidation of arsenite to the less mobile arsenate by significantly enhancing the relative abundance of the gene (130% increase in the 0-5 cm soil zone around MAT). The decrease in As bioavailability significantly reduced As accumulation in rice grains (-30.0%). This work offers a low-cost and sustainable method for mitigating As release in rice paddies by addressing the issue of soil Eh management.
砷（As）是一种主要的环境污染物，通过食用大米会对人类健康造成重大风险。提高土壤氧化还原电位（Eh）已被证明可以降低 As 的生物利用度并减少大米中的 As 积累。然而，缺乏可持续的稻田 Eh 管理方法。为了解决这个问题，我们提出了一种新的方法，该方法使用人造通气组织（MAT）通过模拟湿植物根释放 O 来增加土壤 Eh。我们的研究表明，MAT 方法可持续地将土壤 Eh 水平从-119 增加到-80.7 mV（约 30%），大约 100 天，并且在 MAT 表面半径约 5 cm 范围内。此外，它还导致溶解有机碳、Fe、Mn 和 As 浓度显著降低（-28.5%至-63.3%）。MAT 诱导的 Fe(III)（氧氢）氧化物矿物作为土壤孔隙水中溶解 As 的额外吸附位点。此外，MAT 通过显著增加 基因的相对丰度（MAT 周围 0-5 cm 土壤区域增加 130%）来促进亚砷酸盐向移动性较低的砷酸盐的氧化。As 生物利用度的降低显著降低了大米中的 As 积累（-30.0%）。这项工作提供了一种低成本和可持续的方法，通过解决土壤 Eh 管理问题来减轻稻田中 As 的释放。
