城郊公路两侧主要森林类型铅含量及分布规律

Pb concentration and distribution in main tree species on both sides of highway in suburbs of Nanjing City.

对南京城郊３１２国道两侧主要森林类型林木不同器官中Ｐｂ含量和分布规律的研究表明，不同树种、同一树种不同器官中Ｐｂ含量有明显差异．火炬松对Ｐｂ污染的净化能力强于杉木、栎树．汽车尾气排放的Ｐｂ污染影响范围在离公路两侧１００ｍ以内，主要在４０ｍ以内范围．有林地土壤由于有林木及林下植被的覆盖，其Ｐｂ含量（尤其是表层０～２０ｃｍ范围内）明显降低，说明林分可有效地降低土壤中Ｐｂ的污染程度．林木不同器官对Ｐｂ尘的吸附率在１８０％～２８１％之间，以叶片吸附能力最强；不同树种比较。

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.