Accumulation characteristics of PAHs in multimedia from various urban functional areas

Taking Shanghai city as an example, the study analyzed the difference of concentration levels in road dust, soil and leaves besides roads. The reasons and mechanisms of the accumulation characteristics were also been discussed. The result shows that, in a same functional area, road dusts and soils accumulated more PAHs while leaves did less, and the concentrations of PAHs in P. orientalis L. leaves were higher than those in Buxus sinica leaves. Total PAHs concentrations in road dust and soil ranged from 8992 ng·g^-1 to 141723 ng·g^-1, averaged in 54964 ng·g^-1, and from 9306 ng·g^-1 to 146689 ng·g^-1, averaged in 56883 ng·g^-1, respectively. Total PAHs concentrations in P. orientalis L. leaves and Buxus sinica leaves varied from 2423 ng·g^-1 to 32883 ng·g^-1, with a mean value of 12983 ng·g^-1, from 1498 ng·g^-1 to 19418 ng·g^-1, with a mean value of 7612 ng·g^-1. Among various functional areas, there were significant differences in PAHs concentrations in road dusts and soils while those in leaves were similarly. PAH homologue concentrations in road dusts and soils had significant difference in various functional areas with the priority of high molecular homologues. However, PAH homologue concentrations in leaves were similarly dominated by low molecular homologues. The accumulation characteristics were closely corresponding with the physicochemical property of PAHs and the main accumulation ways of PAHs in multimedia.