贵阳市道路灰尘和土壤重金属来源识别比较

Comparison of sources of metals in road-dust and soil in Guiyang

通过对89个城市土壤样和78个道路灰尘样中重金属含量的对比,利用多元统计方法识别研究区的元素来源.结果显示道路灰尘元素含量一般高于土壤.就均值而言,灰尘中Hg、Cd、Pb、Cu、Cr含量超过土壤中相应元素含量,灰尘中Zn含量与土壤中Zn含量相当,只有灰尘中As含量略低于土壤.灰尘中元素含量都高于中国和贵州表层土壤背景值,土壤中元素含量除Pb外都高于中国和贵州表层土壤背景值.Cd,Cr,Pb,Hg,Cu和Zn含量较高主要是受人为因素的影响.贵阳市道路灰尘和土壤中8种元素有着不同的来源.相关分析、主成分分析表明交通排放等人为因素是重金属主要来源,外来客土也是重金属重要来源;灰尘Pb主要来源于交通排放和钢铁厂;而土壤Cr具有复合污染的特征,主要来源于外来客土.

In this study, multivariate statistical analysis was employed for source identification with 78 road dust samples and 89 soil samples. The average concentrations of metals in the road dust were much higher than those in the soil, except for As. Concentrations of road dust metals were higher than the soil background contents in China and Guizhou, and concentrations of associated soil metals were also higher than the soil background contents in China and Guizhou except for Pb. High concentrations of Cd, Cr, Pb, Hg, Cu, Zn were influenced by anthropogenic sources. The metal sources of road dust and soil samples were evidently different, as derived by correlation coefficient analysis （CA） and principal component analysis （PCA）. Transportation emissions and steel plants were the main metals sources, followed by soil transported from other regions. Pb in road dust mainly came from traffic emission and steel plants, while Cr of soil mainly from soil transported from other regions