基于BCR和HG-ICP-AES的矿区土壤重金属污染特征分析

建立了基于BCR法(连续提取法)和HG-ICP-AES技术的土壤重金属形态含量的检测方法。在选定的实验条件下，HG-ICP-AES对Hg, Pb和As的检测限分别达到0.6，1.5和0.8 ng·mL-1。对国家标准沉积物样品中Hg，Pb和As的含量进行对照测定，检测结果与推荐值一致，标准物质中Hg, Pb和As多次重复测定的RSD均<8%。应用本法实测了湘西某有色金属矿区土壤中Hg, Pb和As各形态的含量，发现矿区土壤中Hg, Pb和As均以残渣态为主，有机态和Fe-Mn氧化态次之，酸交换态含量较少；与对照区相比，矿区土壤中酸交换态、Fe-Mn氧化态、有机态、残渣态Hg, Pb和As的含量分别增加1.2, 3.0, 47, 272倍(Hg); 1.2, 4.6, 8.1, 4.5倍(Pb); 1.5, 2.9, 3.3, 2.2倍(As); 表明湘西矿区土壤同时存在Hg, Pb和As的复合污染。

Pollution Characteristics Analysis of Hg, Pb and As in Soils of Nonferrous Metal Mine Area by the BCR and HG-ICP-AES Technique

A method for the determination of Hg, Pb and As concentrations in soil and sediment samples by the BCR and HG-ICP-AES technique was described. Under the optimum experimental conditions and instrumental operation parameters, the detection limits of Hg, Pb and As of the method were 0.6, 1.5 and 0.8 ng x mL(-1) , respectively. Meanwhile, the analytical results of Hg, Pb and As in the Chinese national standard sediment reference samples were in good agreement with the certified values with the RSDs below 8%. Using the BCR and HG-ICP-AES technique, the content of each chemical species of Hg, Pb and As in soils of nonferrous metal mine area in western Hunan province was studied. The result showed that the Hg, Pb and As contents in soils were dominated by residual form, followed by organic and Fe-Mn oxides form, whereas acid-exchangeable form was rather low. The concentrations of the four Hg species in mine soil were 1.2, 3.0, 47 and 272 times higher than those in the control soil. While the concentrations of Pb and As in the same samples were 1.2, 4.6, 8.1 and 4.5 times and 1.5, 2.9, 3.3 and 2.2 times higher than those in the control soil, respectively. The results indicated that the soil in mine area in western Hunan province was co-polluted polluted by Hg, Pb and As.