Distribution And Geochemical Characteristics Of Heavy Metals In Soils Of Nankou Area,Changping,Beijing

With the rapid development of urbanization and the continuous progress of the economy,human activities have strongly influenced the content of heavy metals in the soil.In this paper,we studied the geochemical characteristics and risk assessment of 8kinds of heavy metals in soils in the northwest of Changping District,Beijing.According the correlation of soil physicochemical properties and heavy metal elements,to elaborate the relationship between soil properties and heavy metals;according to the analysis of multivariate statistical analysis and spatial analysis method and factor analysis,combined with SPSS,MapGis,GS+and other software,multi angle to clarify the origin of heavy metals in soils in the study area;using single factor index method and Nemerow pollution index,geoaccumulation index and potential ecological risk index to evaluation 8 kinds of heavy metals of the current situation of soil pollution in the study area.The main conclusions are as follows:1.The soil in the study area of Hg,Cd,Cu,Pb,Zn of the discrete degree is high,among of Cd,Cu,Pb,Zn compared with the background values of Beijing showed a general enrichment of the state,the space distribution of the high value mainly concentrated centralof the study area,that is Liucun,Tulou east-west area;the discrete degree of As,Cr,Niis smaller,and it is equivalent to the background value of Beijing,high value is mainly distributed in the northwest of the study area.2.Through redundancy analysis,Al₂O₃?Fe₃O₄ and As?Ni?Cr showed good correlation in the study area,while Cd,Cu,Pb,Zn,Hg are related to P,N,and organic matter.However,the distribution of these 8 heavy metals in the study area is not related to the pH value in the study area.3.Through Principal Component analysis,cluster analysis and variogram analysis,the results show that Cd,Cu,Pb and Zn are mainly controlled by human activities.The sources of As,Cr and Ni are mainly natural factors,while Hg elements are mainly affected by atmospheric deposition.Redundancy analysis showed that the 3 heavy metals of As,Cr and Ni were mainly related to Al and Fe minerals.Cd,Cu,Pb,Zn and Hg were mainly affected by N,Zn and organic matter,and the contents of 8 heavy metals in the study area were not related to pH value of soil.4.The evaluation results of heavy metal pollution in surface soil showed that only Cd and Cu were moderately polluted in the soil,and the other 6 heavy metals pollution belonged to a relatively clean level.