贵州牛角塘矿区土壤重金属形态分布特征研究

Speciation and Distribution Characteristics of Heavy Metals in Soil of Guizhou Niujiaotang Lead-Zinc Mining Area

分析贵州牛角塘矿区土壤中重金属Pb、Cd、Cu的含量及化学形态分布及p H值和金属总量对重金属形态的影响,为矿区污染防治治理提供科学依据。采用Tessier5步连续提取法对3种重金属元素的形态进行分析,用SPSS相关分析各形态与p H值和金属总量的关系。结果表明:牛角塘矿区土壤中Cd的污染严重,Pb含量也超过土壤国标二级标准,重金属的生物活性系数与迁移系数皆为Cd>Pb>Cu,Cd的生态风险较大;3种金属在矿区土壤中均以残渣态为主,Cd的可交换态、Cu的有机结合态是几种金属中最高的;土壤的p H值是影响元素形态的重要因素,根据重金属种类的不同影响程度具有差异,各元素的残渣态、有机结合态、铁锰氧化态均与土壤中金属总量呈显著正相关,碳酸盐态和可交换态与总量的相关性与元素种类有关。

The paper studies the content and distribution forms of Pb、Cd、Cu, p H and the total content of heavy metal in the soil of Guizhou Niujiaotang Lead-Zinc Mining Area, and analyses the influence of the above factors on the heavy metal forms. A scientific control strategy for heavy mental pollution remediation in mining area is provided. Using the method of Tessier 5 continuous extraction and SPSS, the paper analyzes the relations between the chemical speciation distribution of Pb 、Cd and Cu and p H value and total metal content in soil.The results show that, the soil is polluted seriously by the Cd, the contents of Pb is exceed the standard of GB 15618-1995. All of the order of the biological activity coefficient and the migra-tion coefficient of metal is Cd>Pb>Cu, and the ecological risk of Cd is serious. The residual fraction was the major species for those three metals in soil, the exchangeable speciation of Cd, and the organic matter fractions of Cu is the greatest within three heavy metals. The p H value of the soil is an important factor that affects the fractionation and distribution of the heavy metal, and the influence extent is different from the kind of the metal. The residual fraction, organic matter fraction and ironmanganese oxides fractions of each element have obvious positive correlation with the total content of heavy metal, and the correlation between the form of exchange and carbonate and the total content of metal is relative to element type.