107国道两侧土壤重金属分布及潜在生态危害研究

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

为了研究公路运营对两侧农田造成的重金属污染状况,以107国道新乡段秦庄村附近农田土壤为对象,按距路基不同的距离布设采样点,用F-AAS法测定土壤中Pb、Cd、Cu、Zn、Cr、Ni的含量,并采用Hakanson指数法评价重金属的潜在生态危害。结果表明公路两侧农田土壤重金属含量随距路基距离的增大而呈降低趋势,各重金属含量的峰值均出现在距路基10～30m处;公路两侧300m范围内土壤受到不同程度的Pb、Cd、Cu、Zn、Cr、Ni污染和潜在生态危害,重金属污染程度为:Ni>Pb>Zn>Cd>Cr>Cu,潜在生态危害综合指数达到中等,主要污染为Cd、Ni,达到强生态危害,其次是Pb、Cu、Cr、Zn,为轻微生态危害;公路西侧土壤污染程度大于东侧;Pb、Cd、Cu、Zn主要来自机动车燃料,轮胎等机件,是典型的交通源重金属元素。

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.