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污染控制技术及原理

Effects of compost on the fractions of copper and cadmium in heavy metal contaminated soil

摘要：通过盆栽茼蒿试验研究了不同堆肥用量对重金属Cu、Cd污染土壤根际土和非根际土中Cu、Cd形态变化的影响.结果表明,随着堆肥用量的增加,非根际土和根际土交换态(含水溶态)Cu含量显著增加,最大值是对照的6.0倍;有机结合态Cu含量在非根际土中显著升高,而在根际土中则先显著升高后降低,两者最大值是对照处理的1.1倍;非根际土中无机结合态Cu含量先降低后升高;非根际土和根际土残渣态Cu含量都先显著增加后基本不变.随着堆肥用量增加,非根际土中交换态(含水溶态)Cd含量显著降低,有机结合态和残渣态Cd含量显著升高,无机结合态Cd含量变化不明显;根际土中,交换态(含水溶态)Cd含量先降低后升高,有机结合态Cd含量显著上升,无机结合态和残渣态Cd先上升后下降.因此,供试堆肥可作为修复剂减弱Cd的危害,但长期施用会造成Cu的累积,应慎重考虑.

Abstract：A pot experiment was conducted to investigate the effect of applying different amounts of compost on the speciation of copper(Cu) and cadmium(Cd) in non-rhizosphere and rhizosphere soil around chrysanthemums. With an increase of compost,the content of exchangeable Cu(including soluble Cu) in non-rhizosphere and rhizosphere soil increased 6.0 times over the control. The content of organic-bound Cu increased significantly in non-rhizosphere soil. However,in rhizosphere soil,the organic-bound Cu first increased and later decreased. The highest increment was 1.1 times as much as that of the control treatment. Precipitated Cu decreased at first and then increased in non-rhizosphere soil. Residual Cu increased at first and then stabilized in both non-rhizosphere and rhizophere soil. For Cd,in non-rhizosphere soil. exchangeable Cd(including soluble Cd) decreased significantly,organic-bound and residual Cd increased significantly,and precipitated Cd varied slightly with the increase of compost. In rhizosphere soil,exchangeable Cd decreased at first and increased afterward,and organic-bound Cd increased significantly,but precipitated and residual Cd increased at first and then decreased. These results suggest that compost can be used as a soil conditioner to prevent Cd toxicity. However,the long-term effects of the accumulation of Cu in soils after repeated compost applications need to be carefully considered.