Spatial Distribution and Ecological Hazard of Heavy Metals in Roadside Soils along the 107~(th) National Highway

To study farmland heavy metal contaminations induced by traffic at the vicinity of a road,farmland soil near the Qinzhuang Village aside the 107th National Highway(Xinxiang City) was chosen as the research object.A sampling transect was perpendicular to the highway.Samples were collected on the line of this transect at a specific interval.The concentrations of Pb,Cd,Cu,Zn,Cr and Ni in these samples were determined by the flame atomic absorption spectrometry(F-AAS) and potential ecological hazards were assessed by Hakanson Index.Results showed that concentrations of heavy metals in roadside soil were decreasing with increasing distance from the roadbed,and the highest concentrations of all heavy metals were at 10 to 30 m away from the roadbed.The zones within 300 m width along the both roadsides have been polluted by Pb,Cd,Cu,Zn,Cr and Ni in different degrees.The heavy metal pollution levels were in following orders:NiPbZnCdCrCu and potential ecological hazard integration index up to medium level.Cd and Ni were the main ecological hazard factors,followed were Pb,Cu,Cr and Zn.The pollution on the western side of the highway was heavier than that on the eastern side.Pb,Cd,Cu and Zn were the typical pollutants originated from the highway.