He Yizhou, Yang Yang, Chi Wenting, Hu Shiwen, Chen Guojun, Wang Qi, Cheng Kuan, Guo Chao, Liu Tongxu, Xia Bingqing
National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
J Hazard Mater. 2024 Feb 15;464:132979. doi: 10.1016/j.jhazmat.2023.132979. Epub 2023 Nov 13.
In paddy fields, periodic flooding and drainage phases can significantly affect the availability of antimony (Sb), but the underlying mechanisms remain unclear. In this study, Sb-contaminated paddy soil was incubated under anaerobic (40 day) and subsequently aerobic (40-55 day) conditions. The Sb fractions was investigated and a kinetic model was established to quantitatively evaluate the main processes controlling Sb transformation. Under anaerobic conditions, the reductive dissolution of iron (Fe) (oxyhydr)oxides, the release of soil colloids, and dissolved organic carbon (DOC) could facilitate the release of Sb(V), while newly released Sb(V) were synchronously reduced to Sb(III) that could be incorporated into the solid phase (34.1%, 40 day) or precipitated as SbS (9.7%, 40 day). After soil aeration, a significant increase in dissolved and extracted Sb(V) (34.7%, 45 day) was observed due to the Sb(III) oxidization by the reactive oxygen species (ROS) generated from Fe(II) oxidization. The dissolved and extracted Sb(V) were simultaneously incorporated into the solid phase as the re-aggregation of soil colloids and DOC, and only contributed to 17.1% of the total Sb content at the end of aerobic phase (55 day). Our results elucidated the mechanisms about how biogeochemical Fe/S/C cycling jointly controlled Sb transformation in paddy systems.
在稻田中，周期性的淹水和排水阶段会显著影响锑（Sb）的有效性，但其潜在机制仍不清楚。在本研究中，受锑污染的稻田土壤在厌氧条件下培养40天，随后在好氧条件下培养40 - 55天。研究了锑的形态，并建立了动力学模型以定量评估控制锑转化的主要过程。在厌氧条件下，铁（Fe）（氢）氧化物的还原溶解、土壤胶体的释放以及溶解有机碳（DOC）可促进Sb(V)的释放，而新释放的Sb(V)会同步还原为Sb(III)，后者可进入固相（40天时为34.1%）或沉淀为硫化锑（SbS，40天时为9.7%）。土壤曝气后，由于Fe(II)氧化产生的活性氧物种（ROS）将Sb(III)氧化，溶解态和可提取态Sb(V)显著增加（45天时为34.7%）。随着土壤胶体和DOC的重新聚集，溶解态和可提取态Sb(V)同时进入固相，在好氧阶段结束时（55天）仅占总锑含量的17.1%。我们的研究结果阐明了生物地球化学Fe/S/C循环如何共同控制稻田系统中锑转化的机制。
