不同母质土壤铁铝氧化物-有机碳的相互作用以及对重金属迁移的影响

Interaction between Iron-Aluminum Oxides and Organic Carbon in Soils with Different Parent Materials and Its Influence on Heavy Metal Migration

  • 摘要: 铁铝氧化物作为重要的矿物成分,其形态对土壤中有机碳含量及其赋存状态具有显著影响,两者的相互作用是土壤环境过程的重要组成部分,尤其是在重金属迁移、转化过程中发挥着关键作用。本文以黑龙江风积和冲洪积母质发育的土壤为研究对象,通过分析不同母质土壤剖面不同形态铁铝氧化物及有机碳分布特征,利用相关分析和冗余分析探讨了铁铝氧化物与有机碳的相互作用以及对重金属元素迁移的影响。通过对比发现,不同母质土壤铁铝氧化物垂向分布存在一定的差异,而有机碳的分布模式具有共性特征。相关分析表明络合态氧化铝(Alp)和游离态氧化铝(Ald)与有机碳的正相关性强于其他形态;络合态铁铝氧化物与大部分重金属的相关性较显著;络合态氧化铁(Fep)、游离态氧化铁(Fed)、无定形态氧化铁(Feo)、Alp与Hg,无定形态氧化铝(Alo)与As、Ni均呈显著正相关。分析认为,由地质冲积作用形成的冲洪积母质土壤中,由于低的pH,游离态和络合态铁铝氧化物较高,易与有机碳结合形成更稳定的络合物;相比之下,由强风力沉积形成的风积母质土壤中,由于高的pH,抑制了铁铝氧化物的溶解,游离态和络合态铁铝氧化物含量低,从而降低了与有机碳的结合能力,导致其有机碳含量较高。进一步分析认为,铁铝氧化物及铁铝氧化物-有机碳复合体通过络合、吸附和共沉淀等方式与重金属结合,从而影响土壤中重金属的迁移和富集。

     

    Abstract: Iron-aluminum oxides, as significant mineral components, exhibit a notable influence on the organic carbon content in soil. The interaction between these two elements constitutes a crucial aspect of soil environmental processes, particularly in the migration and transformation of heavy metals. This study focuses on soils developed from aeolian and alluvial-pluvial parent materials in Heilongjiang Province. By analyzing the distribution characteristics of various forms of iron-aluminum oxides and organic carbon content in different soil profiles, correlation analysis and redundancy analysis was employed to investigate the interactions between iron-aluminum oxides and organic carbon, as well as their manifestations in different parent material soils. Furthermore, the correlations with heavy metal elements were analyzed. Through comparative analysis, certain differences in the vertical distribution of iron-aluminum oxides were observed, while the vertical changes in organic carbon content were similar. Correlation analysis revealed that complexed alumina (Alp) and free alumina (Ald) exhibited a stronger positive correlation with organic carbon compared to other forms. Complexed iron-aluminum oxides demonstrated a significant correlation with most heavy metal elements. Furthermore, complexed iron oxide (Fep), free iron oxide (Fed), amorphous iron oxide (Feo), and Alp showed a significant positive correlation with Hg, while amorphous alumina (Alo) correlated positively with As and Ni. Analysis suggests that in soils derived from alluvial-pluvial parent materials, the low pH environment promotes higher levels of free and complexed iron-aluminum oxides, facilitating stronger binding with organic carbon to form more stable complexes. Conversely, in the soils developed from aeolian parent materials, due to the high pH, the dissolution of iron-aluminum oxides is inhibited, and the concentrations of free and complexed iron-aluminum oxides are low, thereby reducing the binding capacity with organic carbon and resulting in a higher organic carbon content. Further analysis indicates that iron-aluminum oxides and their organic carbon complexes interact with heavy metal elements through complexation, adsorption, and co-precipitation, thereby influencing heavy metal migration and accumulation in soil.

     

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