Study On The Cumulating Character Of Heavy Metal Pollution Along The Highway

Transport is one of the basic industry in national economy, more and more highway have been built and put on with the social development. Inevitably, it brings the problem of environmental pollution. The ash, exhausts, leaking fuels, mechanical wear and vehicle-road wear, all of them have made the highway to be a source polluting to the environment around. And specially, the heavy metal is most concerned. So the study on figuring out the degree of pollution, its pathway and the distributing mechanism is very important.In this paper, the soil samples are collected in four highways in Shan'xi province and detect the heavy metal content in it. Focus on and make sure the status of heavy metal contamination, heavy metal content trends with the varying of the road operating times, the distribution and accumulation (fitting curve and function) with the varying of depth and width. Study shows that: the soil around the highway has been contaminated by heavy metal at different level, especially beside the road, the pollution is very serious, and its content higher than tow degree state standards. The content of heavy metal in the soil shows the obvious laws with the varying of depth and width. The law is in a certain depth range(by the nature of soil), the content of heavy metal increasing with the depth change, reach the max content, then reducing with it change; And the content increasing with the width change, reach the max content, then reducing with it change.And meanwhile the study also shows that the mathematical model about the heavy metal content, soil depth and width is: y = a₁xⁿ + a₂x^n-1+...+ a_nx + a₀, a_i(i=1, 2...n)is the relative coefficient about soil nature, a₀ is the heavy metal content in the surface and roadbed soil. The result is: there are heavy metal contamination along the highway, constructing evaporation ponds is better engineering measures; and understanding the law of heavy metal pollution, takeing effective measures to reduce its hazards.