铅锌冶炼厂周边土壤重金属污染特征研究

Characteristics of Heavy Metal Pollution in Soil Around Lead-Zinc Smelting Plant

通过野外采样和实验室分析,在分析土壤基本理化性质、重金属含量及形态特征的基础上,研究云南澜沧某大型冶炼厂周边土壤重金属污染特征及规律.研究表明,铅锌冶炼厂土壤中总Cd、总Pb和总Zn平均值分别为（2.36±0.14）mg/kg、（287.79±176.45）mg/kg、（161.94±94.57）mg/kg,均超过中国土壤元素背景值和云南省土壤元素背景值.表层土壤重金属污染顺序为Cd〉Pb〉Zn〉Ni〉Cr〉Cu〉As〉Hg,其中表层土壤Cd内梅罗综合污染指数为21.05,属于重度污染;Pb内梅罗综合污染指数2.33,属于中度污染,Zn内梅罗综合污染指数1.79,属轻度污染,但表层土壤尚未受到Cr、Cu、Ni、Hg、As污染.重金属Cd、Pb、Zn含量随土壤深度增加极显著降低（P〈0.01）,Pb、Zn污染主要集中在0~20 cm上,20~80 cm土壤层尚未受到污染,而Cd在0~20 cm、20~40 cm土壤层中均超过《土壤环境质量标准》二级标准.表层土壤中Cd、Pb、Zn总量与DTPA提取态含量呈极显著正相关（P〈0.01）.说明铅锌冶炼厂周边土壤受Cd、Pb、Zn污染.

With the smelting of mine resources, heavy metal pollution in soil is getting serious and endangers hu- man health. A field survey is conducted in this paper to investigate the characteristics of heavy metal pollution in soil around the Lead- Zinc smelting plant located in Lancang city, Yunnan Province. The results indicate that the mean concentrations of Cd, Pb and Zn in the experiment soil are （2. 36± 0. 14） mg/kg, （287.79 ± 176.45） mg/kg and （ 161.94 ± 94.57） mg/kg, respectively, which are higher than that of element back- ground values in soils of Yunnan Province and China. The pollution levels of heavy metals in 0 -20 em depths soil layer at study site are in the orderCd 〉 Pb 〉 Zn 〉 Ni〉 Cr 〉 Cu 〉 As 〉 Hg. According toNemerow integrated pollution index, index of the Cd, Pb and Zn reach 21.05, 2. 33 and 1.79, and the pollution levels are serious, medium and light respectively. Concentrations of Cd, Pb and Zn significantly decrease with the in- creased depth of vertical soil（P 〈0.01 ）. Pb- , Zn- pollution are concentrated in 0 ~20 cm depth soil layer, but are not observed in 20 - 80 cm depth soil layer. In 0 - 20 cm, 20 - 40 em depth in soil layer, concentrations of Cd exceed ＂Environment Quality Standard for Soils＂ （ Grade Ⅱ ）. A significantly positive correlation is ob-served between diethylenetriaminepentaacetic acid （DTPA） and Zn（P 〈0. 01 ）, respectively. The results show that the Lancang city is contaminated by Cd, Pb and Zn. extractable and total soil around the Lead concentrations of topsoil Cd, Pb -Zinc smelting plant located in