7种常用绿化树种在修复镉污染土壤中的应用初探

Preliminary Studies on the Application of Seven Common Green Tree Species in Remediation of Cadmium Contaminated Soil

为研究大生物量树种对Cd污染土壤的修复效果,以毛白杨、馒头柳、臭椿、构树、榆树、白蜡、国槐等7种天津市常用绿化树种为材料,开展大田试验,对比各树种在Cd轻度污染土壤和未受Cd污染土壤中的生长表现(株高和茎粗生长量,成活率),分析Cd污染土壤中各树种不同器官对Cd的吸收和富集能力(BCF),及对土壤Cd的去除能力。结果表明:7种树种在轻度Cd污染土壤上正常生长,其株高和茎粗生长量及成活率均与未受Cd污染土壤无显著差异(P>0.05),说明各树种均对土壤重金属Cd有一定的耐性;地上部器官富集能力表现为毛白杨>馒头柳>榆树>臭椿>构树>国槐>白蜡,根部富集能力表现为毛白杨>榆树>馒头柳>构树>臭椿>白蜡>国槐,各树种根部富集能力均高于地上部;Cd去除能力表现为毛白杨>榆树>馒头柳>臭椿>构树>白蜡>国槐。综合而言,毛白杨、榆树、馒头柳、构树和臭椿每年可去除土壤中Cd大于3.71 mg·m-2,显著高于白蜡和国槐(P>0.05),在原位修复土壤Cd污染中具有广阔的应用前景。

To study the repair effect of large biomass tree species on cadmium-contaminated soil,the field experiment was carried out with seven kinds of common tree species in Tianjin,which included Populus tomentos,Salix matsudana var.matsudana f.umbraculifera Rehd.,Ailanthus altissima,Broussonetia papyrifera,Ulmus pumila L.,Fraxinus chinensis and Sophora japonica L.,the growth status(plant height and stem growth,survival rate)under mild cadmium-contaminated soil and soil without cadmium were compared,and the indices of cadmium uptake and enrichment ability(BCF)in different organs under cadmium-contaminated soil and the removal rate of soil cadmium were analyzed.The results showed that seven species were normally grown on mild cadmium-contaminated soil,which the plant height,stem growth,and survival rate were not significantly different from those without cadmium(P>0.05),indicating that the tree species had certain tolerance to soil cadmium.The BCF of the aboveground parts of seven species was representing as P.tomentosa>S.matsudana var.matsudana f.umbraculifera Rehd.>U.pumila L.>A.altissima>B.papyrifera>S.japonica L.>F.chinensis,and the BCF of the roots of seven species was representing as P.tomentosa>U.pumila L.>S.matsudana var.matsudana f.umbraculifera Rehd.>B.papyrifera>A.altissima>F.chinensis>S.japonica L.,which the BCF of roots was higher than that of aboveground in all the seven species.The removal ability of cadmium was representing as P.tomentosa>U.pumila L.>S.matsudana var.matsudana f.umbraculifera Rehd.>A.altissima>B.papyrifera>F.chinensis>S.japonica L..Comprehensively,P.tomentosa,U.pumila L.,S.matsudana var.matsudana f.umbraculifera Rehd.,B.papysifera,and A.altissima could remove more than 3.71 mg·m-2 of cadmium in the soil every year,which were significant higher than F.chinensis and S.japonica L.,indicating that they had broad application prospects for in situ remediation of soil cadmium pollution.