四种连续提取方案在重金属污染土壤评价中的比较

Comparison of Four Sequential Extraction Procedures Used to Evaluate Trace Metal Distribution in a Contaminated Soil

选取Sposito、BCR、Tessier、Silveira四种连续提取方案,评价其在污染土壤金属形态分析中的应用.四种方案均显示,供试土样的有机态铜和可交换态镉比例较高. Silveira方案提取的无定形铁结合态在Tessier和BCR方案中可归为铁锰氧化态,晶形铁结合态则为残渣态的一部分. Silveira方案提取碳酸盐结合态铜、镉、锌的能力强于Tessier方案,而BCR提取铁锰氧化态铁、铜、锌的能力弱于Tessi-er方案. Sposito方案提取可交换态和有机态镉能力较弱,不适合供试土壤中镉的提取. Silveira方案在研究土壤中铁或与之相关金属元素变化时,在亚热带土壤分析中具有一定的应用价值.

Four sequential extraction procedures(Sposito,BCR,Tessier and Silveira scheme)were compared to determine the fraction distribution of trace metals(Fe,Cu,Cd and Zn)in a contaminated soil around mine.The results of the four schemes showed the organic bound Cu and exchangeable Cd were relative high.The amorphous iron oxide and crystalline iron oxide bound metals in Silveira method were recognized as Fe-Mn oxides and residual fractions in BCR and Tessier methods respectively.Tessier method extracted less carbonate bound form of Cu,Cd and Zn than Silveira method while extracted more Fe-Mn oxides fraction of Fe,Cu and Zn than BCR method.Due to weak ability to extract exchangeable and organic bound Cd fractions,Sposito is not suitable for Cd extraction of this experimental soil.However,when researching Fe oxides and related metal elements of soil,Silveira method is not only applicable for tropic soil but also shows some application value in subtropic soil.