用ICP-AES测定了惠州市不同功能区的典型绿化树种大叶榕和紫荆叶片及其叶面降尘的重金属含量。结果表明,不同功能区植物叶片和叶面降尘的重金属含量差异显著,植物叶片综合污染指数为:商业交通区〉工业区〉居民区〉清洁区,而叶面降尘的综合污染指数则为:工业区〉商业交通区〉居民区〉清洁区。大叶榕叶片的重金属含量略高于紫荆,但差异不显著。降尘重金属污染严重,尤其Cd含量达到了广东省土壤背景值的120倍以上,Pb则为12倍以上。降尘重金属含量是叶片的2~800倍,通过叶片气孔吸收的降尘重金属较少。植物叶片和降尘的重金属含量随交通流量的减少而降低。除Cr和Cd元素外,大叶榕与紫荆叶片的重金属与叶面降尘中重金属相关性不显著。
Based on the land use in Huizhou, Guangdong Province, concentrations of heavy metals ( Cr, Cu, Zn, Cd, Pb ) for two common roadside trees ( Ficus virens var. sublanceolata (Miq.) Comer and Bauhinia blakeana) leaves and their foliar dust in nine sampling sites in different urban areas were determined by ICP-AES. The results showed that heavy metal concentration in leaves was significantly different in various urban areas, and their pollution index was in order of commercial and traffic area (CTA) 〉 industrial area ( IA ) 〉 residential area ( RA ) 〉 control area (CA), and for foliar dust in order of IA 〉 CTA 〉 RA 〉 CA. Leaves of F. virens var. sublanceolata (Miq.) Comer absorbed slightly higher heavy metal than that of B. blakeana. Heavy metal contents in foliar dust were elevated, especially Cd and Pb, which were over 120 folds and 12 folds of the soil background values of Guangdong province, respectively. Foliar dust accumulated heavy metal as high as 2 - 800 times that in leaves, indicating foliage absorbed less heavy metal via its stomata. The concentration of heavy metal in foliage and foliar dust varied with surrounding and traffic density. Presence of Cr and Cd in foliage and foliar dust was highly correlated. So, foliage and foliar dust can be effective indicators of air pollution in areas concerned, and have potential capacity to reduce and remove atmosphere pollution and dust particles.