Abstract: This paper studied the Pb concentration and distribution in main tree species on the both sides of National Highway 312 in suburbs of Nanjing City. The result shows that the Pb concentration differed with same organs of different tree species and different organs of same species. The Pb content in loblolly pine was comparatively higher than that in Chinese fir and oak. The range of Pb pollution from tail gases emitted by automobiles was distributed within 100m apart from the highway, mainly within 40m. The Pb concentration in forest soils, especially in 0～20cm soil layer, was decreased significantly because of the soils covered by forest vegetation, indicating that the forest stands effectively decreased the Pb pollution in soils. The Pb adsorption rates by different organs ranged from 18.0% to 28.1%, with the highest by leaves. Comparing to other trees, loblolly pine had the highest adsorption rate.

Key words: Pb pollution, Forest tree organs, Soil, Both sides of highway