高速公路沿线路面灰尘及土壤中重金属污染特征研究

本文选择昌九、昌樟、温厚三条高速公路为研究对象,采集了路面灰尘和路旁表层土壤,测定了其中锰、锌、铜、铅、锑和镉的浓度。通过分析重金属之间的相关性、重金属含量与车流量之间的关系,比较本研究与国内外相关文献,希望能说明锰、锌、铜、铅、锑和镉这几种重金属的来源,并对这几种重金属的污染状况进行了评价。研究结果表明,交通活动释放的锌主要来源于轮胎磨损;铜和锑主要来源于制动板的磨损;虽然汽油中禁止添加铅,汽车轮轴轴承摩擦、制动衬面摩擦还会释放出铅;轮胎、润滑油和金属表面都会释放出镉;虽然汽油中添加的锰基抗爆剂会向环境中释放锰,但交通环境路面灰尘和土壤中的锰仍主要来源于自然环境。路面灰尘和土壤中重金属含量与车流量之间显著正相关,其浓度从高到低呈现了相似的规律:Zn > Cu、Pb > Sb、Cd。路面灰尘中重金属单项污染指数:Cd≫Zn、Cu > Sb > Pb。土壤中重金属单项污染指数从高到低依次为:Cd > Sb > Cu > Zn > Pb。公路旁环境介质中重金属污染风险等级:Cd≫Cu > Pb > Zn。汽车尾气、制动板和轮胎磨损是交通源污染物的主要来源,而非尾气排放源是交通环境重金属污染物的主要来源。

Pollution Characterization of Heavy Metals in Road Dusts and Soils near Expressways

The traffic-related pollutants are mainly derived from automobile exhausts and the wear of tires, brake linings and bearings. The vehicle-derived metals (Cu, Zn, Cd, Sb, Ba and Pb) are mainly derived from wear rather than from combustion. In this paper, street dusts and associated soil samples were collected from three expressways with rather different traffic densities in Jiangxi Province, and the contents of Zn, Cu, Pb, Cd, Mn and Sb in road dusts and topsoils were measured. Analyzing the correlations between the heavy metals and between heavy metals and traffic volume, and comparing our research results to relevant literature, we wish to constrain the sources of Zn, Cu, Pb, Cd, Mn and Sb. And this research evaluates the contamination levels of Zn, Cu, Pb, Cd, Mn and Sb. The results indicate that heavy metal concentrations in road dusts and soils present similar rules:Zn > Cu, Pb > Sb, Cd. The heavy metal concentrations are highly dependent on traffic volume. The pollution indices are of high level for all of the heavy metals in road dusts. The pollution indices of the heavy metals in topsoils are ranked the high level for Cd, Sb and Cu, light to medium for Zn, and still clean to light for Pb. The potential ecological risks follow the order of Cd > Cu > Pb > Zn.