Study Of Investigation And Assessment On Heavy Metal Pollution Of Urban Soil In Shanghai

With the deepening of the opening up and reform policy,the urbanization is speeding when industry especially heavy industry of manufacturing also achieved rapid advance.While the human activities enable the social development,they also export a large amount of many kinds of heavy metal into the soil which in a large extent causes the soil environment pollution as well as endangers the the health of people and safety of eco-system through dust,ground runoff and enrichment within the food chain.In this dissertation,in addition to the types,ways,characteristics origins and impacts of heavy metal pollution are discussed as well as the status quo of the research home and abroad.In the research,the Shanghai 2010 EXPO planning site,which is now under reconstruction,was selected as the major area for study.At the meanwhile, several areas in the surburbs surrounding Shanghai were also selected as the parallel areas.As for the major area EXPO planning site,grids were demarcated utilizing GIS programming according to 200m? 00m each.The final number of grids was defined 164 after field research was conducted in the area.On the other hand,14 samples were located in Nanhui,Chongming and Jiuduansha respective.During the research,pH,organic matter content and contents for six heavy metal elements including As,Cd,Cu,Ni,Pb and Zn were measured and then classified according to the National Standards of Soil Environment Quality.Statistic softwares like Excel and SPSS were also used for data statistics in order to research and assess the vairents of different heavy metal contents,space distribution,single factor quality index(SI), Nemerrow complex index(NI)and potential ecological risk index(RI).The research conclusions are listed as below: 1.The soil in the research area is alkalescently polluted while the organic matter content is relatively high.2.All the 6 average heavy metal contents are higher than Shanghai background level and at different extents affected by human-caused disturbance;soil in most sampling points are poor than the standard forⅢlevel soil.The 6 havey metals could be sorted below according to different guidelines respectively.According to the soil environment quality: Ni＜Cd＜Zn＜Pb＜Cu＜As;according to the ecological risk: Zn＜As＜Cu＜Ni＜Pb＜Cd.When referring to the co-relation of different elements,Cu-Zn and As-Ni are strongly correlated,Cu-Mn & Pb,Zn-Pb&As&Ni are extremely correlated,which discloses that the pollution might be co-related but come from different origins.3.The research on the spacial difference shows that although there exists discrepancy at certain level,the major trend could be summarized as below: regions majorly consisted of large heavy industry enterprises including Pudong Steel,Port Machinery Heavy Industry and Jiangnan Ship Yard are worse than regions of mixed places as Nanmatou,Bansongyuan and Bailianjing,while other regions are relatively much better in a word.4.Comprehensive Assessment:the calculation and analytical results of NI discloses that nearly two-thirds of all the sample points are medium or even heavier polluted.The RI shows that Potential Ecological Harzard Index are high for major parts of the research area.5.The results of analysis according to different urbanization level shows that with the advance of urbanization and industrialization,the content of heavy metals in the soil will rise while the ecological harzard level will be intensified.In related to the research results,propose are released.As for the areas which are located in the former heavy industrial corporations and not suitable for plants to grow or which RI indexes are higher than 600,enginnering removal method should be carried out in order to renew the surface soil while in other areas,plant rehabilitation could be carried out pertinently and respectively. Meanwhile a variety of feasible suggestions and measures are also proposed for long-term soil management.