Luo Huilong, Chen Juan, Yang Bin, Li Yake, Wang Panpan, Yu Jingjing, Yuan Bei, Zhang Yunhui, Ren Jie, Du Ping, Li Fasheng
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Institute of Resources and Environment, Beijing Academy of Science and Technology, Beijing 100089, China.
Technical Center for Soil, Agriculture and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing 100012, China.
Sci Total Environ. 2024 Dec 20;957:177739. doi: 10.1016/j.scitotenv.2024.177739. Epub 2024 Nov 29.
Research on the use of organic materials as soil amendments for the remediation of Cd-contaminated agricultural land exists. However, the mechanisms based on which organic materials affect the distribution and availability of Cd in soil aggregates remain unclear. Here, Cd-contaminated paddy soil and different bio-based materials were used for rice pot experiments. Rhizosphere soils were separated into six particle sizes. Cd fractions were analyzed with BCR sequential extraction and specific functional groups associated with Cd were characterized using XPS. We found that bio-based materials promoted the formation of large aggregates to different extents. Cd tended to be enriched in fine- and coarse-grained soil particles, which is mainly related to the soil organic matter. Bio-based materials reduced the relative content of the weak-acid extractable fraction and increased the relative content of the reducible fraction, resulting in soil Cd immobilization. Soil dissolved organic matter (DOM) was the key factor affecting the distribution and availability of Cd in soil aggregates and different organic matter and Cd-binding functional groups in aggregates altered the Cd availability in soil. The results provide insight and guidance for understanding the cadmium immobilization mechanism and screening appropriate materials in the remediation of agricultural land.
关于使用有机材料作为土壤改良剂修复镉污染农田的研究已有报道。然而，有机材料影响土壤团聚体中镉的分布和有效性的机制尚不清楚。在此，利用镉污染的稻田土壤和不同的生物基材料进行水稻盆栽试验。将根际土壤分离为六种粒径。采用BCR连续提取法分析镉形态，并利用XPS对与镉相关的特定官能团进行表征。我们发现，生物基材料在不同程度上促进了大团聚体的形成。镉倾向于在细粒和粗粒土壤颗粒中富集，这主要与土壤有机质有关。生物基材料降低了弱酸可提取态的相对含量，增加了可还原态的相对含量，从而使土壤镉固定化。土壤溶解有机质（DOM）是影响土壤团聚体中镉的分布和有效性的关键因素，团聚体中不同的有机质和镉结合官能团改变了土壤中镉的有效性。这些结果为理解镉固定化机制和筛选农田修复的合适材料提供了见解和指导。
