Spatial Distribution And Pollution Evaluation Of Heavy Metal Polluted Soil Beside Highway Based On GIS

Interest in the levels of heavy metal Pollution associated with highway has risen in these years, Influenced by such causes as automobile exhaust gas et al. The dust, soil, vegetable and green belt on the roadside have accumulated a large amount of heavy metals,and become a potential danger. The pollution that heavy metals make to the atmosphere, water and soil will bring direct or indircet threat to human heath. This artiele takes the study to heavy metal pollution in the corse of highway construction and operation in order to put forward some advices and to control the pollution, which has significantly realistic and scientific meaning.In this paper, field investigation, indoor analysis, mathematical statistics, geostatistics, ecology and 3S technology has been used. The sampling area is the highways within 500m, where located in Liutang Branch of Houhu Farm in Jianghan Plain. Analysis of the spatial distribution of heavy metals provides an important basis for revealing the spatial distribution of variables and the establishment of forecast of heavy metals in soil sampling area. At the same time, the prediction model of heavy metals in soil has been researched and established, the model can quickly access soil properties of the heavy metals, mine all the correlation between variables, the spatial variation of the heavy metals can be explanted in details. Through these models and evaluation methods, there is an environmental assessment on heavy metals pollution in soil, and some meaningful results could be get. Key findings are as follows:(1) Spatial distribution of heavy metals in soilThe farmland on both sides of Highway should obtain using Regional kind of community-sets,300 m and 100 m in the two-scale sampling of soil samples, determining soil pH, organic matter, the cadmium, lead total, total copper, zinc content of the total, Using classical statistical method of heavy metals in soil characteristics of the statistical. Results showed that: the whole sample is high in soil cadmium, the entire copper, the entire contents of the zinc Elements, the basic soil samples to determine presence of heavy metal contamination; partial content of organic matter Low, heavy metal absorption capacity weakened, the content of heavy metals in the soil have a certain impact. Application of the statistical methods, all of the variables of the structure of space, access to soil the character of the spatial distribution, trends and the distribution of the correlation between variables influence. Research shows that heavy metals in soil in addition to the highway but zinc, have marked the distance gradually decreasing trend .The heavy metal elements exist certain relevance, including the all-copper, cadmium-wide, all lead, strong presence of organic matter, the whole Zinc related only with the strong presence of organic matter.(2) Evaluation of heavy metal contamination of soilAccording to spatial distribution of heavy metals in the soil, Integration of environmental pollution,matter-element model index evaluation methods, calculated plots of soil pollution index, and on this basis divided environmental pollution levels of this area. It is divided to moderate pollution and light pollution, mainly to moderately polluted area, accounting for 85 percent of the total area. Comparison of the level map measured data and level map of heavy metal pollution prediction model of environmental pollution data, the latter better able to explain the study area of the actual situation of pollution.