山东省高速公路两侧土壤的铅污染及绿化带的防护作用

Lead Pollution Along Expressways and Its Attenuation by Green Belts in Shandong Province

汽车尾气会对高速公路两侧土壤和绿化树木带来一定程度的Pb污染,而两侧的绿化带可对Pb污染起到防护作用,目前这方面的研究还很少。本文对山东省5条主要高速公路两侧土壤和绿化树木叶片Pb含量进行取样测定,研究了山东省高速公路两侧Pb污染现状,并对不同模式绿化林带对公路Pb污染的防护作用进行了评价。结果表明,山东省高速公路两侧土壤存在一定程度的Pb污染,主要集中在路侧50 m范围内;高速公路Pb污染与车流量之间呈显著正相关,车流量对Pb污染有一定指示作用;高速公路Pb污染也明显增加了绿化带内侧树木叶片的Pb含量,车流量较大的公路对树木的污染也越重;在不同绿化模式下,两侧林带对公路Pb污染的防护作用存在较大差别,宽度过大的林带并不是防护Pb污染的理想措施。

Automobile exhaust can bring about Pb pollution to soils and trees along expressway, which can be decreased by green belts to some extent. However, fewer reports are available on this subject. The Pb concentration of soil and tree leaf sampled from roadside were measured and present situation of Pb pollution along expressways in Shandong province was studied. Also, the Pb attenuation by green belt was evaluated for different afforestation mode. The results showed that the pollution existed in roadside soil along expressway, which mainly within 50 m. The positive correlation was found between Pb pollution and traffic vehicle density, which might be used to indicate expressway pollution. The Pb concentration of tree leaf from inner side of green belt was increased by Pb pollution. Large traffic vehicle density resulted in heavier Pb pollution on green trees along expressway. The Pb attenuation by green belt varied much depending on afforestation mode. Green belt with too big width was not ideal to decrease Pb pollution.