长江南京段近岸沉积物和土壤中重金属分布特征分析

通过测定沉积物和土壤中Cd、Pb、Cr、Zn、Cu、Ni 6种重金属元素的平均含量,计算其富集因子,分析长江南京段近岸沉积物和土壤中重金属的空间分布特征,结果表明,几种重金属在沉积物中的富集次序为:CdPbCr1NiCuZn,在土壤中为:CdZnCu1CrPbNi,除Zn和Cu外,其他几种金属在沉积物中的富集程度高于土壤,同时Cd的含量超过土壤环境质量三级标准。以Cd和Pb为例分析了重金属含量与沉积物粒级之间的关系,回归分析显示,Cd、Pb的含量与颗粒物的粒级呈显著的相关性,与细颗粒物的含量有密切关系,细颗粒携带的重金属,在长江水力分选作用下到达下游,成为沉积物中重金属的主要来源。

D istribution and Enrichmentof Heavy M etalin Sedimentsand Soilsin Nanjing Section ofthe Yangtze River

The s six heavy metals Cd, ediments and soils of Yangtze River were analyzed for the contents and enrichment factors of Pb, Cr, Zn, Cu and Ni in order to know their distribution characters. The sequence of EFs was Cd 〉 Pb 〉 Cr 〉 1 〉 Ni 〉Cu 〉 Zn in the sediments, however, Cd 〉 Zn 〉 Cu 〉 1 〉 Cr 〉 Pb 〉 Ni in the soils. The enrichment of other metals in the sediments was higher than soils except Zn and Cu. The concentration of Cd had exceeded the third level of soil environmental quality standards. Taking Cd and Pb as an example analyzed the relationship between content of heavy metal and grain size. Regression analysis indicated a significant corre- lation. Heavy metals and fine particles showed a close relationship. So the heavy metals carried by fine particu- late matter were important source of them in sediments by sorting of Yangtze River.