交通活动对公路两侧土壤和灰尘中重金属含量的影响

为了解公路交通带来的重金属污染及其在公路两侧土壤中的分布规律,对相关研究结果的分析表明,含铅汽油、润滑油的燃烧,汽车轮胎、刹车里村的机械磨损等是公路两侧土壤和灰尘中重金属污染的重要来源.机动车辆排放的含重金属颗粒物或直接沉积在路面灰尘中,或通过干湿沉降沉积在公路两侧的土壤中,使得公路两侧土壤和灰尘中重金属出现不同程度的积累.一般地,公路两侧土壤中重金属含量随着距公路距离的增加呈指数形式下降.公路两侧土壤中重金属的含量及其分布格局因受交通流量、车辆类型、地形与路况、绿化带配置和风、降雨等气象条件的影响而异.

Effect of road traffic on heavy metals in road dusts and roadside soils

In order to gain an understanding of the concentrations and dispersion patterns of heavy metals emitted by motor vehicles and deposited in road and roadside soils,the concentrations and dispersion patterns of heavy metals were analyzed based on previous studies from different cities at home and abroad.Vehicular emissions,especially combustion of lubricants and lead-gasoline,mechanical abrasion of vehicle tyres and brakes,are the major source of heavy metals such as Pb,Zn,Cu and Cd in road dusts and roadside soils.Particulates containing heavy metals may deposit in road dusts directly or in roadside soils via aerial deposition,which brings about the accumulation of heavy metals in road dusts and roadside soils.Numerous studies have indicated that heavy metals such as Pb,Cu,Zn and Cd have accumulated in road dusts and roadside soils of China and some other countries,which may cause adverse effects on human health and environmental quality.Generally,the concentrations of heavy metals in roadside soils decrease exponentially with increasing distance from the road edge.Dispersion patterns of heavy metal contents vary greatly in different regions,and the differences are attributed mainly to the effects of traffic intensity,topographic profiles(up-down hill),road surface and greenbelts in local region,in addition to micro-meteorological factors,such as wind power and speed,direction of dominant winds and rainfall.