基于最小数据集的周至地区土壤重金属地球化学特征及成因分析

Geochemical Characteristic of Heavy Metal in Zhouzhi Area and Analysis of Their Causes Based on Minimum Data Set

周至县是陕西省乃至全国的猕猴桃主产区之一,为了查明周至地区土壤重金属地球化学特征及其成因,采集了周至地区8个典型农用田中226件土壤样品,分析测试了Cu、Pb、Zn、Cd、Ni、Cr、As、Hg、Sn、Co、Mn、V和Fe含量,通过地球化学数据分析、主成分分析、Norm值计算,构建由Cu、Pb、Zn、Cd、Ni、Cr和As组成的最小数据集对周至地区土壤重金属生态风险进行评价,并分析了其成因。结果显示,最小数据集7种重金属的单因子污染指数和综合污染指数值均小于1,潜在生态风险指数为30.90,说明研究区土壤重金属于安全级别。通过相关性分析及主成分分析认为,第1主成分包括Cu、Ni、Cr、Co、Mn和V,其含量与地质背景密切相关;第2主成分包括Pb、Zn和Cd,主要受人为活动影响;第3主成分是As、Sn和Hg,可能受土壤组成的影响或者人为活动的影响。

Zhouzhi County is an important kiwifruit base in Shanxi Province and even in China.226 samples were collected from eight typical agriculture land,the contents of Cu,Pb,Zn,Cd,Ni,Cr,As,Hg,Sn,Co,Mn,V and Fe in soils were analyzed.The geochemical characteristic,potential ecological risk and origin of heavy metal elements in Zhouzhi County were investigated through constructing the minimum data set(MDS),based on correlation analysis,principal component analysis and Norm value calculation by using Cu,Pb,Zn,Cd,Ni,Cr and As.The results revealed that the single-factor pollution index was less than 1,and aggregate pollution index was 30.90,indicated the concentrations of heavy metals in soil meet the safety standard.The correlation analysis and the principal components analysis were made to discuss the cause of the heavy metals.It is believed that the first cluster including Cu,Ni,Cr,Co,Mn and V were mainly influenced by geological background;the sec-ond cluster including Pb,Zn and Cd were mainly related to human agricultural production;the third cluster including As,Sn and Hg were affected by geological background and human activities.