Study On The Sources And Influencing Factors Of Soil Heavy Metals In The Typical Area Of Daye City

With the development of economy,the increasingly serious soil heavy metal pollution problem has become one of the main factors affecting human health.The heavy metals in the soil may accumulate through the food chain through crops such as rice and eventually enter the human body.When the content of heavy metals in the human body accumulates to a certain threshold,it will have an impact on human health.Therefore,it is of great significance to study the migration and transformation rules,sources and influencing factors of heavy metals in the soil.In this paper,Lingxiang town and Chengui town of Daye City were selected as the study area.Through collecting surface soil samples,irrigation water samples and fertilizer samples,the content and spatial distribution characteristics of heavy metals in the surface soil of the study area were analyzed,and the geochemical evaluation of soil quality was performed.On this basis,the sources of heavy metals in the soil were basicly analyzed by comparing the heavy metal content in each sample by combining SPSS analysis,and the influence of different soil types,land use methods,soil physicochemical properties,and other factors on the heavy metal content were described.Conclusions: 1.The content of heavy metals in the surface soil of the study area is relatively high.Arsenic(As),cadmium(Cd),copper(Cu),mercury(Hg)are greatly affected by human activities,Cd,Cu,lead(Pb),As and Zinc(Zn)are over standard,the over standard rate of Cd is 87.72%,and the coefficient of variation is 1.32;2.Through the geochemical evaluation of the land quality in study area,we found that the soil there is mainly of the third grade,accounting for 93.38%,mainly controlled by Cd;3.Through principal component analysis,correlation analysis and cluster analysis,we found that chromium(Cr)?nickel(Ni)?As and Cu have strong correlation on the main factor one.Pb,Zn and Cd have strong correlation on the main factor two,so it was infered that Cr,Ni,As and Cu might come from the same pollution,Pb,Zn and Cd may come from the same pollution,and the pollution source of Hg might be different from other heavy metals.Combined with the decrease of Cd,Pb and Zn contents in the vertical profiles from the surface layer to the deep layer,thedistribution of atmospheric dry and wet deposition,the content of heavy metals in irrigation water and fertilizer,the pollution sources of heavy metals may be mostly from the surrounding mining areas,and some of them are inherited from the geological background.4.By studying the content of heavy metals in different soil types and land use status,we found that As,Cu,Pb,Zn are slightly higher in red soil,while Cd,Cr,Ni are slightly higher in paddy soil.It may be related to the different physical and chemical properties of the two soils.The content of Cd,Cr,Cu and Ni in cultivated land is the highest among these,while the content of As,Hg and Pb in forest land is higher.It may be that human activities have changed the physical and chemical properties of the soil,thus causing this phenomenon;5.Soil pH,Soil-organic-matter,iron-manganese(hydrogen)-oxides,clay-minerals,nitrogen(N),phosphorus(P),selenium(Se),all affected the content of heavy metals in soil.Morever,all of them had a strong positive correlation with heavy metals,while the elements rich in clay minerals,such as aluminum(Al),potassium(K),calcium(Ca),magnesium(Mg),silicon(Si)have a significant negative correlation with heavy metals.