山东烟台金矿区及城镇周边土壤重金属化学形态分布及转化

THE CHEMICAL SPECIATION DISTRIBUTION AND TRANSITION OF HEAVY METALS IN SOIL AROUND GOLD ORE DISTRICTS AS WELL AS CITIES AND TOWNS IN YANTAI,SHANDONG PROVINCE

土壤中不同形态重金属及其转化的影响因素研究对于了解重金属的地球化学行为具有重要意义。以山东烟台金矿区及城镇周边典型土壤为例,探讨了土壤中不同形态重金属与土壤有机质、黏粒、磁化率和pH值的关系及其生态危害性。结果表明:土壤中大多数重金属以残渣态和铁锰氧化态存在,而Cd以离子交换态为主;土壤酸化可使Ni、Zn、Cd、Hg的活动态含量增加;对于Pb污染严重的土壤,使土壤pH维持在中碱性环境,可以降低Pb危害;防止土壤盐碱化是消除土壤As污染的有效措施;土壤有机质含量增加可明显降低Pb、Hg、Ni等活动态含量,随黏粒含量增加,Pb、Zn等离子交换态含量占总量的比例略有减小;土壤磁化率对了解土壤酸化的状况和土壤污染程度有较好的指示作用。

It is very important to study the factors that affect the change of different forms of heavy metals in soil so as to understand their geochemical behaviors. In this paper,the typical soil in Yantai gold ore district and surrounding areas was described,organic matter,clay,the relationship and the ecological harm of magnetic susceptibility and pH in soil with different forms of heavy metals in soil were also discussed. Some conclusions have been reached: the main existing forms of heavy metals are residual state and Fe-Mn oxide state,whereas the main existing form of Cd is ionic exchangeable form; soil acidification may increase the content of Ni,Zn,Cd and Hg in activity form; if the soil is seriously polluted by Pb,the maintenance of an alkaline environment can reduce Pb harmfulness, and the prevention of salinization is an effective measure for eliminating As pollution in soil. The improvement of organic matter content may reduce the active state form content of Pb,Hg and Ni,whereas the increase of clay content may slightly reduce the percentage of ionic exchangeable form of Pb,Zn; soil magnetic susceptibility is a fairly ideal indicator for acidification situation and pollution degree of soil.