城市不同交通圈(带)土壤重金属多元统计分析及空间分布研究以武汉市为例

STUDY ON MULTIVARIABLE STATISTICS AND SPATIAL DISTRIBUTION OF URBAN SOIL HEAVY METALS AT DIFFERENT TRAFFIC CIRCLE(BAND)——WITH THE EXAMPLE OF WUHAN

土壤重金属污染是近年来备受重视的环境问题,其不仅直接破坏环境质量,还间接危害人体健康,因此研究城市土壤中重金属的累积和分布状况具有一定的意义。选取武汉市不同交通圈为研究区域,分析了表土中Ni、Cd、Cr、Cu、Pb和Zn 6种重金属元素的累积状况和污染来源,评价了重金属的污染程度及生态危害等级,并运用Arc GIS空间插值得到元素的空间分布图。得出以下结论:(1)就平均值而言,Ni、Cr、Cu 3种元素均在省背景值以内,Cd平均值约是国家二级标准的10倍,累积最为严重;(2)多元统计分析结果显示6种元素可聚类为两类,Ni、Cr和Cd、Cu、Pn、Zn,前者主要污染源为气候、母质、年代等成土因素,后者主要受到交通、工业等人为活动及成土母质的的影响;(3)不同研究区累积情况不同,内环最严重,三环带次之,二环带最小;(4)研究区重金属污染评价及潜在生态风险评价结果为重度污染或强度生态危害,且程度上都是内环>三环带>二环带。

Soil heavy metal pollution is one of the environmental issues that paid much attention in recent years. It＇s not only directly destroy the environmental quality, but also do great harm to the human health indirectly. So it＇s significant to study the accumulation and distribution of heavy metal in the city soil. In this study, we analyzed the accumulation status and the pollution source of Ni, Cd, Cr, Cu, Pb and Zn in the topsoil in the different traffic circles in Wuhan, and estimated the level of pollution and ecological hazard of the heavy metal, also obtained the spatial distribution map of the elements with the spatial interpolation by Arc GIS. The conclusion is as follows.（1） The mean of heavy metal of Ni, Cr, Cu are lower than the background value of Hubei province, the average value of Cd is almost ten-fold of the national second-level standards. Its accumulation is the most serious.（2） The multivariate statistical analysis shows that the six elements can be clustered into two kinds. One kind is Ni and Cr, the other is Cd, Cu, Pn and Zn. The former＇s pollution source is mainly the soil-forming factors such as climate, parent material and decades, the latter is mainly affected by the influence of parent material and human activity such as traffic and industry.（3） The pollution conditions varied from different research area.The accumulation in the inner ring is the most serious, the third ring＇s pollution is the second, and the second ring＇s pollution is the minimum.（4） The assessment results of heavy metal pollution and ecological risk showed that the research area was serious polluted or highly ecological hazarded, and the degree of inner ring was bigger than that of the third ring,and the degree of third ring was bigger than that of the second ring.