贵阳市不同空间高度灰尘和重金属沉降通量

采集贵阳市不同空间高度灰尘样品,分析灰尘及其中常量元素Ca和Fe、微量有害重金属Cd、Cr、Cu、Ni、Pb和Zn的沉降通量随空间高度的变化,通过引进灰尘沉降量,结合灰尘中微量有害重金属含量,采用单因子指数法和内梅罗综合指数法评价不同空间高度灰尘重金属导致的环境风险.结果表明:灰尘沉降通量随着楼层增高而减小;不同楼层灰尘元素含量变化差异不大,Fe、Cd、Cu、Ni、Pb元素含量在不同空间高度上随楼层增高而增大,而Cr和Zn元素是随着楼层增高而减小; 8种元素沉降通量分布总体趋势是随楼层的升高,沉降通量降低,尤以Ca、Cr和Zn表现最为明显;引进灰尘沉降量评价灰尘重金属导致的环境风险显示1~3层和7层环境风险较高,4~6层灰尘重金属导致的环境风险较低,Cd、Cu、Pb和Zn是主要风险元素.

Vertical characteristics of deposition fluxes of dust and heavy metals of Guiyang City

Dust was an important pathway of human heavy metal exposure. With the emergence of urban high-rise building, the vertical space of human daily life gradually extended upward. Dust and its heavy metal located on the windowsill and other platform at different height of the building was remarkable. In this study, dust deposition on the windowsill at different height (1th-8th floor) from three buildings in Guiyang city was collected and the deposition fluxes of dust and elements including Ca, Fe, Cd, Cr, Cu, Ni, Pb and Zn was analyzed. Further, the environmental risk due to heavy metals based on loadings per day was assessed by the single-factor contaminant index and Nemerow multi-factor index method. The results showed that: the deposition fluxes of dust decreased with the increases of the height of the ground. The content of elements showed small changes in dust at different height: the contents of Fe, Cd, Cu, Ni, and Pb increased with the height, while the contents of Cr and Zn in dust decreased with the height. In general, the element deposition fluxes decreased as the height of the ground increase, especially Ca, Cr and Zn. The risk assessment based on the deposition fluxes of heavy metals showed that the 1th-3th floor and 7th floor were in higher risk condition, while the 4th-6th floors were in lower risk condition, and Cd, Pb, Cu, and Zn were the main risk elements.