杭州城市土壤重金属的化学形态及环境效应

Chemical speciation of some heavy metals in urban soil in hangzhou city and environmental effects

通过对杭州城市土壤重金属异常中Hg、Cd、Pb、Zn、Cu采用改进的连续浸提实验进行形态分析结果表明,表层土壤中Hg以残渣态和强有机态为主,Cd以铁锰氧化态、弱有机结合态、残渣态和离子交换态为主,Pb、Zn、Cu以残渣态、弱有机结合态和铁锰氧化态为主。相比之下,Cd与Cu的活性组分分别为最高和次高,部分蔬菜样品中重金属含量超标,对该地区农产品的安全已构成威胁。研究发现,上述重金属除与地质背景、土壤理化性质有关外,与人类经济活动关系尤为密切。

The urban soil samples in Hangzhou were studied for the chemical speciation of Hg,Cd,Pb,Zn and Cu in the synthesized abnormity of heavy metals by a modified sequential extraction procedure and the result shows that Hg is mainly in residual and strong organic phases, Cd is larely associated with the Fe-Mn oxide phases, infirm organic, residual phases and exchangeable fractions, and Pb, Zn and Cu are mainly in the residual, infirm organic phases and Fe-Mn oxide phases. The percentage contents of Cd and Cu associated with available fractions is the highest and second respectively, content of heavy metals in the part of vegetable samples was found to be higher than National Food Hygiene Standard and their hazards to farm products safety in this area. Study indicated that besides geological background and the physical and chemical propertys of soil, and heavy metals is closely related to mankind economical activitys.