岩溶区土壤铁锰结核重金属元素形态分析

Analysis of Heavy Metals in Soil Fe-Mn Nodules in Karst Area

为研究土壤铁锰结核中重金属元素形态以及生物可利用性,采用连续提取法对岩溶区土壤铁锰结核重金属元素的形态进行了分析。结果表明,土壤A、B层铁锰结核Cd、Cr、Cu、Pb、Zn、Mn均以残渣态所占比例最高,A层分别为94.85%、86.30%、95.08%、88.90%、95.46%、64.81%,B层分别为95.67%、83.89%、95.87%、85.62%、97.05%、53.19%;Cr元素的有机态、Pb元素的铁锰氧化态所占比例超过了10.00%,Mn元素的铁锰氧化态所占比例仅次于残渣态;土壤A、B层铁锰结核生物可利用态所占比例均较低,潜在可利用态所占比例以Mn最高,Cr和Pb的潜在可利用态也略高,应防止Mn、Cr、Pb对土壤环境造成的潜在污染。

Speciation of heavy metals in soil Fe-Mn nodules and bioavailability in karst area were studied using the sequential extraction method.The results showed that in the soil Fe-Mnnodules of A and B layers,residual fraction was the highest proportion for the elements Cd,Cr,Cu,Pb,Zn and Mn.The proportions of both organic fraction of Cr and Fe-Mn oxides fraction of Pb were more than 10.00%,and Fe-Mn oxides fraction of Mn was second only to residual fraction.Bioavailability of all heavy metals was very low.The potential availability of Mn was the highest,followed by Cr and Pb,which should be considered to prevent their pollution to environment.Speciation of heavy metals had some directive significance for soil improvement in Fe-Mn nodules in karst area.