College of Life and Environment Sciences, Central South University of Forestry and Technology, Changsha, 410004, China; Hunan Research Institute for Nonferrous Metals Co., Ltd., Changsha, Changsha, 410100, China; Hunan Provincial Soil Pollution Remediation and Carbon Fixation Engineering Technology Research Center, Changsha, 410004, China.
College of Life and Environment Sciences, Central South University of Forestry and Technology, Changsha, 410004, China.
Chemosphere. 2024 Sep;364:143239. doi: 10.1016/j.chemosphere.2024.143239. Epub 2024 Sep 3.
Combined Cd (cadmium) and As (arsenic) pollution in cultivated land affects the safety of crops production and endangers human health. Rice (Oryza sativa L.) is a crop that uptakes Si (silicon), and Si can effectively promote rice growth and mitigate heavy metal toxicity. This study examined the effect and mechanism of Si-rich amendment (HA) prepared by aerobic combustion of rice husk on Cd and As accumulation in iron plaque and rice seedlings via hydroponic experiments. HA enhanced the vitality of rice growth because of its Si content and increased the amount of amorphous fraction iron plaques, furthermore, Cd content was decreased while the As was increased in both amorphous fraction and crystalline fraction iron plaques, resulting in the contents of Cd and As decreases by 10.0%-38.3% and 9.6%-42.8% for the shoots, and by 13.4%-45.2% and 9.9%-20.0% for the roots, respectively. In addition, X-ray diffraction and X-ray photoelectron spectroscopy illustrated significantly more FeO, MnO and MnO in the iron plaque after HA supply and the simultaneous existence of Mn-As and Mn-Si compounds. This result revealed less Cd from iron plaque and more As retention with HA supply, reducing the amount of Cd and As up taking and accumulation by rice seedlings. HA is beneficial to rice growth and reduce the absorption of heavy metals in plants. At the same time, HA is environmentally friendly, it can be used for the remediation of paddy fields contaminated by Cd and As.
农田镉（Cd）和砷（As）复合污染影响作物生产安全，危及人类健康。水稻（Oryza sativa L.）是一种吸收硅（Si）的作物，硅能有效促进水稻生长，减轻重金属毒性。本研究通过水培实验，考察了稻壳有氧燃烧制备的富硅改良剂（HA）对铁斑和水稻幼苗中 Cd 和 As 积累的影响及其作用机制。由于其 Si 含量，HA 增强了水稻生长的活力，并增加了无定形铁斑的数量，此外，Cd 含量在无定形和结晶铁斑中分别降低了 10.0%-38.3%和 9.6%-42.8%，而 As 含量分别增加了 9.6%-42.8%和 9.9%-20.0%，分别为地上部分和地下部分。此外，X 射线衍射和 X 射线光电子能谱表明，HA 供应后铁斑中 FeO、MnO 和 MnO 的含量显著增加，同时存在 Mn-As 和 Mn-Si 化合物。这一结果表明，HA 供应后铁斑中 Cd 的含量减少，As 的保留量增加，从而减少了水稻幼苗对 Cd 和 As 的吸收和积累。HA 有利于水稻生长，减少植物对重金属的吸收。同时，HA 环保，可用于修复 Cd 和 As 污染的稻田。
