不同钝化剂对Cu、Cr和Ni复合污染土壤的修复研究

利用盆栽试验研究了不同钝化剂(沸石、牡蛎壳、鸡蛋壳、硅藻土和聚丙烯酰胺(PAM))对生长在重金属污染土壤上的青菜(Brassica chinensis L.)生物量、重金属吸收以及超氧化物歧化酶的活性(SOD)和丙二醛(MDA)含量的影响,同时,通过对土壤p H和土壤重金属提取态的分析,探讨了钝化剂影响青菜生物量和重金属吸收的可能原因。结果表明:钝化剂加入可显著降低青菜地上部分Cu、Zn、Ni和Cd的含量及其氧化性损伤和脂膜损伤(SOD和MDA指标显著降低)。施入钝化剂后,土壤p H显著提高,重金属提取态Cu、Zn、Pb、Ni和Cd普遍降低(硅藻土处理除外)。相关性分析表明,土壤p H与提取态重金属Pb、Zn、Ni和Cd呈显著的负相关,而青菜中的重金属Zn、Ni和Cd的含量与土壤提取态含量呈显著正相关。综合考虑,单一钝化剂牡蛎壳和沸石+牡蛎壳+鸡蛋壳(FMJ)组合对降低青菜重金属吸收的效果尤为显著,可推荐作为重金属复合污染土壤的改良剂。本研究为重金属中轻度污染菜地的土壤修复提供了一种新方法。

Remediation of Heavy Metal Contaminated Soil with Different Amendments

Pot experiment was conducted and the soil pH and DTPA extractable heavy metals in the soils were analyzed to investigate the effects of different amendments (zeolite, oyster shells, eggshell, diatomite, and polyacrylamide) on the biomass, metal accumulation, SOD and MDA of Brassica chinensis L. in this study. The results showed that the accumulation of metals on Brassica chinensis L. was greatly decreased with addition of amendments, meanwhile, SOD and MDA levels were also reduced, which indicated that the amendments could alleviate the toxicity of metals. To elucidate the possible reasons for the effects of amendments on Brassica chinensis L., the changes in soil pH values and DTPA-extractable metals (Cu, Zn, Pb, Ni and Cd) were determined. The results suggested that soil pH values increased significantly, while DTPA-extractable metal concentration decreased significantly with the addition of amendments. Moreover, a negative correlation was found between soil pH and the concentrations of DTPA-extractable metal in soils, while a positive one was observed between the amount of metals in Brassica chinensis L. and the concentrations of DTPA-extractable metal, which indicated that soil pH and DTPA-extractable metals in soils would be the primary factors affecting the biomass, accumulation of metals and SOD and MDA of Brassica chinensis L. Overall, the combination of zeolite, oyster shells and eggshell or only oyster shells is the best amendment for the remediation of heavy metal contaminated soil in this study, which provides a new method for the remediation of heavy metal contaminated soils.