Study On Heavy Metals And Basic Chemical Properties Of Soil On One Side Of Provincial Road 104

The discharge of harmful substances such as heavy metals coming from road traffic behavior,to a certain extent,led to the road nearby soil heavy metal pollution,so as to make the highway near the soil ecosystem increased risk.Agricultural and pastoral areas are the ecological fragile areas of China,and the heavy metal pollution of the road in this area has further enhanced the ecological vulnerability.The paper select the north farming-pastoral zone of provincial highway 104 Wu Chuan – Zhaohe as the research object,using field investigation and laboratory analysis to analyse content of heavy metal and soil chemical properties to the road side of farmland,forest land,grassland,assessing the soil pollution degree and soil ecological security,then get the following conclusions.(1)With the increase of distance from roadbed,content of soil chemistry like nitrogen,phosphorus and potassium in a downward trend,six kinds of soil heavy metal content in a downward trend too,the declining trend owes to the different land use types.Six mount peak generally appear in the content of soil heavy metals from the roadbed 5-10 m range,downward trend is different because of different land use types.With the increase of soil depth,in addition to pH,cadmium is not obvious,content and other chemical properties of soil heavy metal content is a downward trend,obviously within 0 to 10 cm soil layer change is bigger,small variations in 10-30 cm soil layer.(2)The correlation between soil chemical properties and soil heavy metals varies according to the type of land used.The highest degree of correlation complexity is agricultural land,followed by grassland and finally forest land.The correlation of the same kind of heavy metal with the same chemical properties in different land use types are different,for example,in two farmland,soil nitrogen,available nitrogen,have no correlation with any kind of soil heavy metal.In two forest land,soil nitrogen,available nitrogen have correlation with five kinds of heavy metal,and in the two grassb land,soil nitrogen,available nitrogen are associated only with zinc.(3)From the perspective of the sources of heavy metal in soil,the sources of heavy metal in soil of different land types are different within the range of 5-200 m from the roadbed.Such as farmland and woodland in chromium(Cr)and zinc(zinc)significantly,the relevance of the source for the road traffic and soil parent material,grass zinc(zinc)and lead(Pb)significantly related,source for the road traffic and soil parent material.(4)The cumulative index evaluation results show that the three land use types in heavy metal pollution are mainly concentrated in subgrade 5-30 m range,with a mild,50 m separate state of heavy metal pollution to mild,other area for pollution-free state.The highest level of pollution is forest land,followed by grassland and finally agricultural land.(5)Potential risk assessment results show that the ecological risk of soil heavy metal is low in the range of 5-200 m from the roadbed of the three land types.The highest level of ecological risk is agricultural land,followed by woodland and finally grassland.