Spatial Distribution And Environmental Significanceof Heavy Metals In Soil In Ziketan Of Xinghai Basin

Soil is the material basis for human survival and an important part of the ecosystem.With the development of the economy,the emission of industrial wastes,pesticide and fertilizer application and solid waste stacking make heavy metals accumulate continuously in soil.People pay more and more attention to the problem of excessive accumulation of heavy metals in soil.Heavy metals accumulated in soil for a long time will enter into animal and plant through food chain,which will pose a potential threat to all kinds of animals and plants and human beings.Ziketan of Xinghai basin is located in the core area of Sanjiang source which has a sensitive and fragile ecological environment.It is very necessary to study the distribution characteristics of heavy metals in the soil for this area.In this paper,we make Ziketan of Xinghai basin as the study area.A total of 35 soil samples were collected.The contents of heavy metals Cu,Pb,Zn,Cr,Ni,Cd,As and Hg in soil samples were detected by ICP-MS and ICP-AES.Using geostatistics and GIS technology to research correlation between heavy metals in soil,spatial distribution,spatial pattern characteristics and the distribution characteristics of heavy metals in soil under different erosion types.The main contents as follows:(1)The heavy metals in the study area were classified into five groups.The specific classification as follows: ?(Pb?Zn?Cr),?(Cu?Ni),?(As),?(Cd),?(Hg).(2)The results of ordinary Kriging interpolation of heavy metals in the study area show that the distribution characteristics of heavy metals are similar and different.The contents of Cu,Pb,Zn,Cr,Ni and Cd were higher in the southwest and north of the study area.The content of As is high in the southwest,central and north of the study area.Hg is high in the north of the study area.(3)According to the spatial pattern index at the type level,the area composition characteristics of heavy metals in the study area were dominated by medium and low value patches.The shape characteristics of the plaques are complex in the middle and low content areas,and very low and high content areas are relatively simple.The patch connectivity of Cu,Zn,Cr,Ni,Cd and As is better.The high and low value of Pb has better patch connectivity.Hg has good connectivity in low,middle and high grades,but there is no obvious distribution rule.(4)The contents of all elements in the wind hydraulic composite erosion area are low.The contents of Pb,Zn and Cd in hydraulic erosion area are relatively high,and the content of Hg in freeze-thaw erosion area is high.