[Polycyclic aromatic hydrocarbons in plant leaves from Peking University campus and nearby in summer season].

Leaves of 6 plants were collected from two sites on and around Peking University campus in summer season of 2003. PAHs in the leaf-wax and tissues were determined simultaneously with leaf-wax content, tissue lipid, specific surface, and stomata density. The results were compared to investigate the possible sources of PAHs in the leaves. For both leaf-wax and tissue samples, levels of PAHs depended on plant species and were lower in the samples from campus than those from outside of campus in short distance to busy traffic, suggesting a significant influence of vehicle emission. The concentrations of PAHs in leaf-wax were 1-2 orders of magnitude higher than those in leaf tissues. While the PAH profiles in the leaf-wax and leaf tissues were similar in general, the relative contents of volatile compounds were higher in the tissues than in the wax. Negative correlations were identified between PAHs concentration in the leaf-wax and the wax content and between the tissue PAH content and stomata density.