The Influence Of Land Use Change To Soil Heavy Metal Pollution In Nantong City

In recent years,because people develop and use land unreasonably,and leave many pollutants into the soil through various channels.At present,in all environmental pollution, soil pollution problem are playing an increasingly important role.Because the soil and groundwater,hazardous waste,industrial waste,pesticides and waste emissions have closely relation.Once the soil contaminated,it's very difficult to restore.Land use as the human use of land's comprehensive reflection of various activities,it is the most common,direct and profound factors to impact on soil quality.Land use changes can cause many changes in natural phenomena and ecological processes,such as soil nutrients,surface vegetation,soil heavy metals content.Heavy metals in soil and crop production,food security,environment and human health are closely related,and it is the most basical token and the most important research in soil quality changes.Bases on Nantong,this thesis researches the influence of seven cities and counties land use change in Nantong(the work mineral,transportation and rural settlements land use) to their respective area of soil heavy metal pollution.ChapterⅠof the thesis mainly introduces the research's purpose,meaning and methods etc.,In chapterⅡ,it mainly introduces the research's district.In chapterⅢ,it statisticses and analyses the cities and counties's land-use on the work mineral,transportation and rural settlements from 1990 to 2004.And finds in 2004 three kinds of land use have grown in both cities and counties than these in 1990.And calculates the the relative rates of land-use changes,using the method of the relative rates of the land use changes.The results showes that only Haimen and Nantong' land use change range of the work mineral,transportation and rural settlements are greater than the land use change range of the whole city.And know that a certain type of land use's relative rate of land use change have extently relationship with such land use variety quantity,but the relationship between them is not significantly. In chapterⅣ,respectively,evaluates the soil heavy metals pollution of seven cities and counties.And there are six heavy metals,Hg,Pb,As,Cd,Cr and Cu.Selectes two methods,they are one factor pollution index number way and comprehensive pollution index number way.Evaluation results shows that all cities and counties in Nantong,in addition to heavy metals Pb content high,have yet polluted the farmland soil in Haimen City,heavy metal content of the other five are low,have not yet polluted the farmland soil.ChapterⅤis on the basis of research results of the chapterⅢand chapterⅣ,and reserch the work mineral,transportation and rural settlements land use change to impact the single and comprehensive heavy metal pollution.Theresults shows that soil heavy metalpollution,including the single heavy metal pollution and heavy metals comprehensive pollution,have a certain relationship with the land use change.The work mineral land use changeinfluences the soil heavy metals Hg,As,Cd,Cr and Cu pollution most obviously, Secondly is transportation land use change,and it influences the soil heavy metals Pb pollution most obviously.Rural settlements change influences the soil heavy metals pollution less obviously than the work mineral and transportation use change.To the comprehensive heavy metal contamination of soil,the effect of the work mineral land use changeimpacting on soil heavy metals pollution＞the effect of changes in transportation land use＞the effect of changes in rural settlements.Finally,basing on this research findings,makes a corresponding suggestion.