南京市典型水域沉积物中重金属形态分布特征

Research on the Chemical Speciation of Heavy Metals in Sediments of Typical Waters in Nanjing City

采用顺序提取的方法对南京市典型河流和湖泊水域的沉积物进行重金属化学形态研究,分析了Cu、Zn、Pb、Cd、Ni、Cr 6种重金属元素在不同水体沉积物中各个形态赋存的含量分布特征。结果表明,6种元素生物有效性排序为:Cd> Pb>Zn> Cu> Ni> Cr,其中Cd和Pb以弱酸提取态和可还原态为主要存在形态,其不仅会对上覆水体产生二次污染,对水生动植物也具有较强的危害性。另外,通过结果间接反映出受人类生产生活影响大的水体,受污染的程度更高,各种金属元素赋存的形态也更易迁移转化,在环境治理方面更应受到重视。

Heavy metals sequential extraction was applied to examine the spatial occurrence characteristics of Cu ,Zn ,Pb, Cd, Ni, Cr in sediments of rivers or lakes in Nanjing. The results showed the bioavailability of 6 heavy metals ranked as follow ： Cd 〉 Pb 〉 Zn 〉 Cu 〉 Ni 〉 Cr. Cd and PI） exist mainly in reducible state and acid soluble state, and they not only produce secondary pollution on the overlaying water but also have higher risk to aquatic organisms. Moreover, the more human production and living activities affect the water environments, the higher degree of pollution appears, and the migration and transformation of specification of heavy metals become more easily, which should be paid more attention.