Influence of traffic exhausts on elements and polycyclic aromatic hydrocarbons in leaves of medicinal plant Broussonetia papyrifera

Paper mulberry (Broussonetia papyrifera) is one of medicinal plants in Asia and Pacific countries. Tender leaves of B. papyrifera from a heavy traffic site (HTS) and a low traffic site (LTS) were collected for the determination of non–metallic nutrient elements (N, P and S), metallic nutrient elements (K, Ca, Mg, Cu, Zn, Mn, Ni, Cr and Mo), non–essential metallic elements (Al, Cd and Pb) and 16 EPA priority polycyclic aromatic hydrocarbons (PAHs). Leaves of B. papyrifera were abundant with P, S, K, Mg, and Ca. Traffic exposure did not change the leaf contents of non–metallic and metallic nutrient elements (except for K and Cr), but did cause significant accumulation of Al, Cd, Pb and PAHs in the leaves. Results of this study implied that traffic exhaust–stemmed accumulation of Al, Cd, Pb, and PAHs in the leaves of B. papyrifera could be potentially detrimental to human health when the leaves were utilized for medicinal raw materials. The collection of B. papyrifera leaves from polluted sites for medicinal utilization and consumption should be abandoned or intensively monitored.