岩溶地区公路路侧土壤中重金属污染及其评价

在2002年和2004年,分别对地处岩溶地区的衡昆高速公路湖南段、207国道、322国道的多个路段,在距离公路5 m、10 m、15 m、25 m、40 m、60 m、80 m、100 m、120 m、150 m处采集土壤样品,采用原子吸收光谱法测试土壤中的Cu、Pb、Zn、Cd等重金属元素的含量,并对其结果进行了分析与评价。研究结果表明,岩溶地区公路两侧土壤中的Pb、Zn、Cd等重金属元素的含量在公路运营之后显著增加,其中,土壤中Cd元素的污染严重,轻度污染的元素为Pb、Zn,基本上未受到Cu的污染影响,土壤对重金属元素的吸附及污染程度为:Cd>Pb>Zn>Cu。重金属污染影响范围自公路起大约80~100 m;岩溶地区公路路侧水田中重金属元素含量较旱地、果园低,但影响范围更广。

Pollution of Heavy Metals in Soil Along Highway in Karst Area and Assessment

Soil samples are collected respectively in karst area along several sections of Hengyang-Kunming Expressway,No.207 National Road and No.322 National Road in 2002 and 2004,with the site of 5 m,10 m,15 m,25 m,40 m,60 m,80 m,100 m,120 m,150 m away from highways.Then the levels of heavy metals(Cu,Pb,Cd,Zn) in soil samples are determined by Atomic Adsorption Spectrophotometer and their results are analyzed and discussed.The research results indicate that in karst area the levels of heavy metals in soil samples along the highway increase prominently after the highway operation.The soil samples are highly polluted by Cd,slightly polluted by Pb and Zn,and not polluted by Cu.The adsorption capacity of soil to heavy metals and its pollution levels are in the following order: Cd>Pb>Zn>Cu.In karst area,two zonal pollution areas are distributed along the both sides of highway road with a width between 80 and 100 meters.Among these zonal pollution areas,the levels of heavy metals in paddy field is smaller than in dry land and orchard,but its incidence is wider.