郑汴路路旁土壤重金属积累及其潜在风险评估

Accumulation and Potential Risk Assessment of Heavy Metals in Roadside Soils along Zhengzhou-Kaifeng Highway

为研究郑汴路路旁土壤重金属污染状况和潜在风险,选取郑汴路杏花营段和圃田段为研究对象,通过计算表层土壤重金属积累速率、年变化率,分析了路旁土壤中Pb、Cd、Ni、Cu、Zn和Cr的含量与分布、积累状况及潜在污染风险。结果表明：Cu、Cr、Cd、Zn和Pb为交通源重金属,含量峰值出现在距路基10~50 m之间。公路运营时间越长,路旁土壤重金属含量越高;通车密度越大,重金属积累速率越大。2个断面交通源重金属平均积累速率均为Zn〉Pb〉Cr〉Cu〉Cd,年变化率均为Cd〉Cr〉Pb〉Zn〉Cu;圃田断面积累率和年变化率均高于杏花营断面。2个断面Pb、Cd、Cr和Cu的潜在风险为正值,其中以Cd的风险最大;圃田断面Pb、Cd、Cr和Cu的潜在污染风险高于杏花营断面。杏花营断面土壤Zn潜在风险为负值,表明已经发生污染。

Two soil sampling transects in Xinghuaying and Putian along the Zhengzhou-Kaifeng highway were chosen in this study,for the analysis of concentration,distribution,accumulation and potential risks of Pb,Cd,Ni,Cu,Zn and Cr in soils.The results showed that the maximum values of Cu,Cr,Cd,Zn and Pb derived from traffic were found from 10 m to 50 m from the highway.The longer the operation time of highway,the higher was the concentration of heavy metals in soils along highway;the higher the vehicle flow,the higher was the accumulation velocity.The orders of mean accumulation velocity and annual changing rate of heavy metals derived from traffic in two transects were Zn Pb Cr Cu Cd and Cd Cr Pb Zn Cu,respectively,and the values were higher in Putian transect than those in Xinghuaying transect.The potential risks of Pb,Cd,Cr and Cu in two transects were positive,with the higher risk of Cd and higher risk in Putian transect than those in Xinghuaying transect.The potential risks of Zn in Xinghuaying transect was negative,which meant soils had been polluted.