钝化剂对污染土壤汞钝化效果及辣椒吸收汞的影响

Effects of Amendments on Inactivation of Soil Mercury in the Soil and the Enrichment of Absorption by Pepper

【目的】探究三种钝化剂(碳酸钙、氧化钙和硅酸钙)对污染土壤汞(Hg)的钝化效果及辣椒吸收汞的影响。【方法】以贵州万山汞矿区汞污染耕地土壤为研究对象,以碳酸钙、氧化钙和硅酸钙为钝化材料,采用盆栽试验方法,研究三种钝化剂对土壤pH、汞化学形态和有效汞变化的影响,同时考查在外源钝化剂的驱动下,辣椒植株汞含量和汞转运系数的变化特征。【结果】碳酸钙、氧化钙和硅酸钙的施用分别使土壤pH提高0.74~2.28、2.11~5.24和1.79~2.62个单位,土壤活性态汞含量显著降低,残渣态汞含量显著升高,有效汞含量显著降低,且施加0.1%的氧化钙对土壤有效汞降低效果最佳。三种钝化剂均可使辣椒根、茎和果实汞含量降低,且随着钝化剂施加量的增加而降低,其中氧化钙对辣椒根部汞含量降低效果最好。三种钝化剂对辣椒植株各组织汞转运的影响存在差异,施用三种钝化剂均可促进辣椒根中汞向茎和叶中转运,但抑制辣椒根中汞向果实转运。【结论】三种钝化剂均可作为汞污染土壤的钝化修复材料,且均显著抑制辣椒吸收汞,其中,0.1%的氧化钙对土壤汞的钝化修复效果更好,值得推广应用。

[Objective] The experiments were carried out to explore the passivation effect of passivators including CaCO3, CaO and CaSiO3on mercury(Hg) contaminated soil and Hg contents in peppers. [Method] A pot experiment was conducted to study the effects of three passivators on the pH, Hg and the biological availability of Hg in soil which was collected from Wanshan Mercury Mine in Guizhou Province. Besides, the Hg contents and Hg transport coefficient in pepper plants driven by exogenous passivators were investigated. [Result] The applications of CaCO3,CaO and CaSiO3could increase respectively pH of soil by 0.74-2.28, 2.11-5.36 and 1.79-2.62. The three passivators could decrease the contents of active state and biological Hg availability and increase the contents of residual form Hg in soil. The application of calcium oxide has the best effect on reducing the effective Hg in soil, and its proper amount was 0.1%. The application of three passivators reduced the effective Hg contents in pepper root, stem and fruit. The Hg content of pepper root, stem and fruit decreased with the application of passivators, the pepper leaf was opposite.The effects of the three passivators on Hg transport in pepper tissues were varied. The three passivators promoted the transport of Hg from capsicum root to stem, and they also promoted the transport of Hg from capsicum root to leaf, but inhibited the transport of Hg from capsicum root to fruit. [Conclusion] All of the three passivators can be used as passivation materials for the remediation of Hg-contaminated soil. In general, the remediation effect of CaO is the best, and its proper amount is 0.1%, which is worth popularizing and applying.