矿山强酸性多金属污染土壤修复及麻疯树植物复垦条件研究

Remediation of strongly acidic mine soils contaminated by multiple metals by plant reclamation with Jatropha curcas L. and addition of limestone

采用温室盆栽实验,研究了在不同剂量(质量分数分别为0、0.10%、0.25%、0.5%和1.0%)石灰石改良条件下,大宝山矿强酸性多金属不同污染程度土壤中麻疯树的生长状况和吸收金属特征,并探讨了麻疯树在酸性土壤中生长的抑制因素和石灰石改良适宜剂量.研究表明,在低污染酸性土壤中,Cu和Pb的高活性可能是抑制麻疯树生长的主要因素;而在高污染酸性土壤中,Cd、Cu、Zn等金属的高活性及由强酸引起的Al毒也可能是抑制麻疯树生长的主要因素;石灰石通过提高土壤pH值和降低多金属的生物有效态含量,促进了麻疯树在低污和高污土壤中的生长,其最佳剂量分别为0.25%和0.5%;石灰石可以不同程度地降低麻疯树地上部和地下部的Cd、Cu、Pb、Zn和Al含量,同时随石灰石用量的增加,其金属含量基本呈降低趋势;麻疯树地下部金属含量高于地上部,且石灰石对麻疯树地下部金属(除Cd外)含量降低幅度较地上部大.因此,种植麻疯树与石灰石改良是联合修复大宝山矿酸性多金属污染土壤的有效措施之一.

In a greenhouse pot experiment, the dose-response effects of limestone addition （mass fractions 0,0.1% ,0.25% ,0.5% and 1.0% ） on the growth performance and metal uptake characteristics of Jatropha curcas L. grown on different multi-metal contaminated, strongly acid soils from Dabao Mountain mine were studied. Factors suppressing plant growth as well as the feasible dosage of limestone are also discussed. In the soils with lower levels of pollution, high bio-availabilities of Cu and Pb appeared to be the primary factors inhibiting the growth of Jatropha curcas L. , while in highly polluted soils, the growth inhibition of Jatropha curcas L. mainly resulted from the high bio-availability of Cd, Cu and Zn, as well as Al toxicity caused by the strong acidity. The growth performance of Jatropha curcas L. was improved both in the lower and highly polluted soils by the increase of soil pH and decrease of bio-available metal contents （ Cd, Cu, Pb, Zn and A1） achieved by the addition of limestone. The optimum dosage of limestone was 0.25% for soils with lower pollution levels and 0.5% for soils with higher pollution levels. The concentrations of Cd, Cu, Pb, Zn and Al in the shoots and roots of Jatropha curcas L. were reduced to different extents by the limestone and basically decreased with the increasing amount of limestone. The metal concentrations in roots were higher than in shoots, and the drop in metal concentrations （except Cd） caused by the limestone was higher in roots than in shoots. Therefore, the combination of planting Jatropha curcas L. and limestone amendment is one of the most effective ways to remediate acid soils from Dabao Mountain which are polluted with multiple heavy metals.