甘肃省张掖-永昌地区土壤重金属元素地球化学特征

摘要

Spatial distribution characteristics of soil metals in Zhangye-Yongchang area of Gansu Province were studied in this paper. The results show that the study area is mainly characterized by the pollution of Cd,As,Cr and Ni.Industrial waste water and industrial enterprises,human activities and atmospheric dust constitute the major sources of soil pollution in the study area.Viewed from the comprehensive evaluation map of the degree of soil pollution,Grade one,Grade two,Grade three and Grade four quality areas possess 1.87%,87.13%,9.92%and 1.09%of the total area respectively.The current situation of soil pollution shows that heavy metals pol-lution in soil is mainly of Grade one and Grade two,which suggests the fairly good overall quality of the soil in the study area.Phase state analytical results of Cd,As,Cr and Ni show that Cd,As,Cr and Ni are mainly characterized by residual fraction.However,the Cd element is characterized by bound and soluble fractions,which account for about 5%of the total amount,and this situation is dan-gerous and deserves much attention.%通过对甘肃省张掖-永昌地区土壤重金属元素富集与分布规律的研究表明，研究区土壤以Cd、As、Cr、Ni污染为主，工业废水、厂矿企业、人类活动及大气降尘是研究区土壤的主要污染源。从土壤污染程度综合评价图来看，全区土壤一级质量区占总面积的1．87％，二级质量区占总面积的87．13％，三级质量区占9．92％，四级质量区占1．09％。从土壤污染现状来看，重金属土壤以一、二级为主，说明研究区土壤总体质量较好。从土壤Cd、As、Cr、Ni相态分析结果看，各元素多以残渣态为主，但Cd的离子结合态和水溶态占总量的5％左右，是极其危险的，需要引起重视。