城市道路两侧土壤重金属分布特征及生态风险评价

摘要

By collecting the soil on both sides of Road G209 in Lvliang City,the distribution characteristics of Zn,Cu,Ni,and Pb in soil were studied,the ecological risk was evaluated by single factor pollution index method and Nemerow comprehensive index method.Results showed that the further the straight line of the sampling point from the road,the lower the soil heavy metal content was,and the heavy metals mainly concentrated in arable stratum (0 ～20m),and presented an obvious vertical decreasing trend.Soil heavy metal pollution levels were as follow,Pb (moderate pollution) ＞ Cu (slight pollution) ＞ Ni (slight pollution) ＞Zn (uncontaminated),the ecological risk of these heavy metals was V,which belongs to heavy pollution level.The emission of automobile exhaust is the main source of pollution,and the application of pesticides and fertilizers is also the main sources of pollution for agricultural land.%通过采集吕梁市G209线公路两侧土壤,研究土壤中锌、铜、镍、铅4种重金属的分布特征,并采用单因子污染指数法和内梅罗综合指数法进行生态风险评价.结果表明:采样点距离公路直线距离越大,土壤中重金属含量越低,且主要富集在0～20m可耕层,表现出明显的垂直递减规律.土壤重金属污染程度为:Pb(中度污染)＞Cu(轻微污染)＞ Ni(轻微污染)＞Zn(未污染),生态风险评价等级为V,属于重污染.汽车尾气的排放是主要污染来源,对于农业用地,农药、化肥的施用也是主要污染源.