淹水土壤中4个耐水湿树种的重金属积累能力

Heavy Metal Accumulation in Four Flooding-Tolerant Tree Species Grown in Flooded Soil

[目的]比较研究4个耐水湿树种沙柳、杞柳‘微山湖’、水紫树和墨西哥落羽杉在浙江杭州一处重金属污染稻田中的生长情况和重金属积累能力,为重金属污染土地的树木修复提供依据。[方法]实地采样,测定树木各项生长指标,用电感耦合等离子体质谱仪和电感耦合等离子体发射光谱仪测定土样和树木不同部位中重金属含量,分析比较不同树种的重金属耐受力和积累能力。[结果]表明:在土壤Cd、Zn、Pb、Cu不同污染程度下,4个树种能够维持生长,表现出较强的适应性。不同树种对重金属的积累能力存在差异,杞柳‘微山湖’对Cd、Zn、Cu的积累量最大,分别为462.58、4 341.32、261.86 mg·株-1,沙柳对Pb、Mn积累量最大,分别为106.97、577.61 mg·株-1。在当地栽植密度下,经过6 a的生长,杞柳‘微山湖’对Cd、Zn、Pb、Cu、Mn迁移量分别达到3.70、34.73、0.66、2.10、4.23kg·hm-2,沙柳对Zn迁移量达到22.26 kg·hm-2,水紫树在4 a内对Mn迁移量达到3.80 kg·hm-2。[结论]沙柳和杞柳‘微山湖’对Cd和Zn具有较强的积累能力,水紫树和墨西哥落羽杉分别对Mn和Cu污染的淹水土地具有修复潜力。

[Objective]To compare the growth and ability of heavy metal accumulation in four flooding-tolerant tree species（Salix interga ‘Weishanhu＇,S. psammophila,Nyssa aquatica,and Taxodium mucronatum） through a field experiment. [Method] By filed sampling,the growth indexes of different tree species were investigated,and the heavy metal contents in different parts of trees and soil samples were determined by ICP-MS and ICP-AES. [Result]The results show that the four tree species could maintain normal growth and showed relative strong adaptability in the soil polluted by Cd,Zn,Cu and Pb at different degrees. The ability of heavy metal accumulation varied among tree species. S. interga ‘Weishanhu＇showed the maximum total accumulation of Cd,Zn and Cu（462. 58,4 341. 32,261. 86 mg · plant-1）. S. psammophila showed the maximum total accumulation of Pb and Mn（106. 97,577. 61 mg·plant-1）. Under the local planting density,after six years of growth,S. interga‘Weishanhu＇removed Cd 3. 70,Zn 34. 73,Pb 0. 66,Cu 2. 10,Mn 4. 23 kg·hm-2 respectively,S. psammophila removed22. 26 kg Zn per hectare,N. aquatica removed 3. 80 kg Mn per hectare in the past four years. [Conclusion]Thisstudy shows that S. psammophila and S. interga ‘Weishanhu＇have advantage on accumulating Cd and Zn,N.aquatica and T. mucronatum have potential ability on remediating Mn and Cu contaminated soil,respectively.