北京城区大气颗粒物与地表土壤金属元素空间关联分析

The spatial coupling relationship between atmospheric particulates and heavy metal of surface soil in Beijing urban area

为研究北京市区大气降尘金属来源及其与表层土壤的关系,在北京市区五环内的典型地段采集落尘与土壤样品。研究中使用电感耦合等离子体原子光谱仪（ICP-AES）测定了9种金属元素Cd、Cu、Zn、Fe、Pb、V、Ti、Mn、Al的质量分数。结果显示,降尘和土壤中Al、Fe两种元素所占比例最大,质量分数分别为16 144.8、12 881.9μg.g-1和21 400.9、815 712.2μg.g-1。其次降尘中Zn、Ti和土壤中Ti、Mn居第二位。随后基于灰度关联法对大气降尘与表层土壤的金属元素关系分析可知,大气降尘与表层土壤是高度关联的,关联值均介于0.92~0.95之间,二者间关联较为紧密。其中在空气降尘对表层土壤的影响研究中分析得出,空气降尘对表层土壤的影响与采样点的空间位置变化相关性不强,与风向、风速等自然环境因素的关联度较大。在表层土壤对空气降尘的影响研究中分析得出,表层土壤对空气降尘的影响度随采样点环境变化较大,尤其是北京南站。最后,通过对降尘金属元素进行因子分析得出,第一因子Z1同时与Pb、V、Ti、Mn、Al、Fe、Cu、Cd等元素有较大关系;第二个因子Z2与Cd、Cu等元素有较大的相关性;第三个因子Z3与Zn、Fe等元素有较大相关性,与其它7种元素的相关性不明显。前三因子Z1、Z2、Z3方差累积贡献率可达97.2%,由此可知,降尘来源主要与风引起的地面扬尘,与塑料制品的焚烧,冶金、化工等工业影响及轮胎磨损有关。

This paper discussed heavy metal sources of ambient dust fall and its relationship with surface soil in Beijing. Urban dust and soil samples were collected from typical areas within five rings of Beijing. The concentrations of heavy metal elements （Cd, Cu, Zn, Fe、Pb、V, Ti, Mn、 A1） were determined using ICP-AES. The results presented that in the dust fall and soil, A1 and Fe had the largest proportions, their quality were 16 144.8 and 12 881.9 μg. g-l in the dust fall, 21 400.9 and 815 712.2μg·g-1 in the soil, respectively. The concentrations of Zn and Ti in the dust fall and Ti and Mn in the soil had the second largest proportions. Then, based on Grayscale relative method analysis, relationship of heavy metal elements between the dust fall and surface soil was determined. The analysis results showed that their relationship was significant and their correlated value was range from 0.92 to 0.95. In the analysis of dust fall impact on surface soil, the results indicated that dust fall influence on the surface soil was associated with natural environmental factors, including wind direction and speed. But it was not strongly associated with changing of spatial sampling locations. In the study of the soil influence on dust fall, degree of association changed largely as sampling environment changing, especially in the Beijing South Station. Finally, based on factor analysis, the first factor Z1 had a significant relationship with Pb, V, Ti, Mn, A1, Fe, Cu and Cd. The second factor Z2 correlated with Cd and Cu and the third factor Z3 correlated with Zn and Fe were obviously. The Z1, Z2 and Z3 had an accumulative contribution rate 97.2%. Thus, sources of dust fall was mainly interrelated with raise dust, domestic wastes, combustion of plastic, metallurgy, chemical industries and tire wearing, etc.