材料期刊网

比较了硝酸（ HNO3）、硝酸?盐酸（ HNO3∶HCl＝3∶1）、硝酸?盐酸?双氧水（ HNO3∶HCl∶H2 O2＝3∶1∶1）和硝酸?盐酸?高氯酸（HNO3∶HCl∶HClO4＝3∶1∶1）等4种消解液对土壤中铅（Pb）、镉（Cd）、砷（As）、铬（Cr）、镍（ Ni）、铜（ Cu）和锌（ Zn）等7种重金属元素的萃取效率。结果表明，硝酸?盐酸?高氯酸混合液的萃取效果最好，硝酸?盐酸混合液次之。通过对6种土壤标准物质的分析发现，除了Cr之外，其他重金属元素在土壤中的混酸微波可提取态含量与总含量接近。土壤中的Cr有一部分是以铬铁矿的形式存在，在环境中相对较为稳定，采用混酸微波可提取态的Cr来评估其对环境的危害能够获得更加准确的结果。重金属与土壤的结合强弱与成土母质相关，冲积母质的土壤中Pb、Zn和Cu的结合较强，萃取相对较难，Cd、Ni和As与土壤的结合强弱则与成土母质关系不大。采用最优的消解液萃取矿区河流底泥和土壤中的重金属，ICP?MS分析结果表明，底泥中重金属含量较高，应为尾砂冲积而成，矿区周边的土壤也受到不同程度重金属的污染。

The extraction efficiency of heavy metals ( Pb, Cd, As, Cr, Ni, Cu and Zn) in soils was compared using four digestive solutions: HNO3 , HNO3?HCl, HNO3?HCl?H2 O2 and HNO3?HCl?HClO4 . The highest extraction efficiency was obtained with HNO3?HCl?HClO4 , followed by HNO3?HCl in six certified reference soils. The concentrations of acid extractable heavy metals were close to their total amounts except chromium. Due to the high proportion of chromite which is stable in environmental condition, it would be more appropriate to assess environmental risk of chromium using acid extractable concentrations. Adsorption of heavy metals to soils was related to parent materials. Due to strong adsorption to alluvial sediments, lead, zinc and copper were relatively difficult to be extracted. The adsorption of cadmium, nickel and arsenic to soil represented weak correlation with parent materials. The proposed extraction method was applied to extract heavy metals from sediments and field soils around a mining area. The results determined by ICP?MS illustrated that the sediments contained high concentrations of heavy metals and were likely water?carried alluviation of tailings. The field soils were contaminated by heavy metals by various degrees.