Research And Traceability Of Soil Quality On Heavy Metals In Suburb Agricultural Soils Of Shanghai

Shanghai Agriculture soil survey has been more than 20 years from now, during which most localities haven’t been carried out other soil quality survey or evaluation again.This topic investigate the the content of heavy metals in surface soils on the outskirts of Shanghai, which relying on the research project of the land survey of vegetable and food crops soil organized by Shanghai Environmental Monitoring Center. Domestic and foreign different evaluation criteria and geostatistics multivariate statistical methods had been used in the article to propose a suitable heavy metal pollutant contaminated Factor Screening Method.This is the first time of large-scale survey on the Shanghai agricultural soils, which would make a considerable practical significance.The survey results showed that pollution levels of heavy metals and metal effective states were low and potential ecological harm was small. Fuzzy mathematical model showed that all the evaluation levels were good. But two contents of Ni and Cu in Fengxian District and two contents Cd in Chongming Island were above GB secondary standard value. Different levels of heavy metals accumulating phenomenon also found in evaluation regions. Cu and Zn contents were relatively higher in Fengxian district vegetable soils and Cd content was higher in Chongming Island rice fields. Multivariate statistical analysis showed that there might be Cu-Zn, Pb-Hg and As-Cd combined pollution in agricultural soils. PCA and Cluster Analysis showed heavy metal elements were divided into four factors. Natural sources elements were Mn-Ni-Cr. Anthropogenic sources elements were Cu-Zn-Hg, Pb-Hg and As-Cd. Application of organic manure, fertilizer and traffic pollution could be the main reasons for heavy metal accumulations. The impct of organic manure and traffic pollution were more prominent in Fengxian District and fertilizer pollution was prominent in Chongming Island. Spatial distribution showed heavy metal content decreased gradually from west to east in Fengxian District and decreased gradually from northwest to southeast in Chongming Island.