Study On Spatial Distribution Of Harmful Elements In Soil Of Donglai Area,Inner Mongolia

This article based on the project of "Northeast Black Land 1: 250000 Land quality Geochemistry Survey" of China Geological and Environmental Monitoring Institute.By collecting background datum related to the research area.A total area of 100 km~2 in Donglai area was taken as the research object,and 468 soil samples were collected to determine the content of harmful elements and other characterization data of the topsoil were determined at the same time.Based on the principle of geostatistics and spatial analysis method,combined with SPSS,Arc GIS software,this article analyzes the spatial distribution of harmful elements in topsoil in Donglai area.Firstly,by analyzing the contents of eight harmful elements in the surface soil of the study area,statistical characteristics and normal distribution tests were performed.The results showed that compared with the background value of soil in Kailu county,the contents of eight harmful elements in topsoil were more than 1.2 times,and the topsoil was polluted by different degrees of harmful elements.The average variation degree of the eight harmful elements was medium variation,which was mainly affected by human activities.Cr and Ni,Cu,Zn,Pb,As,Cd harmful elements basically satisfied the normal distribution.Secondly,the Kriging interpolation method was used to generate a spatial distribution map of the contents of eight harmful elements in the topsoil of the study area,and the regularities of spatial distribution of harmful elements in the study area was studied.The distribution range of Cr,Ni,Cu,Zn,Pb,As,Cd in the high value area of the topsoil was the same,which was mainly distributed near the village,which was closely related to the influence of human activities.Then,combined with multivariate statistics and spatial analysis technology,the pollution sources of harmful elements are analyzed.The results showed that there was a very significant positive correlation between Cr and Ni,Cu,Zn,Pb,As,Hg,Cd eight harmful elements in soil.The probability of these eight harmful elements coming from the same pollution source was high,which was mainly affected by human activities.Ni,Cu,Zn,Pb,As and p H had significant positive correlation.It is found that the continuous overuse of pesticides and fertilizers is the most important factor causing the enrichment of harmful elements in soil.Finally,by the Nemeiro's comprehensive pollution index method was used to evaluate the pollution degree of harmful elements in the topsoil of the study area,and it was found that the topsoil pollution degree was moderate pollution,0.85% of the study area is slightly polluted,13.25% of the study area is mild polluted,37.18% of the study area is moderate polluted and 48.72% of the study area is severe polluted.Through the potential ecological risk assessment method,it is concluded that the degree of regional ecological risk is medium harm.