Spatial Distribution And Pollution Assessment Of Uranium And Heavy Metals In Soil Around Uranium Mill Tailing

The uranium tailing had put into operation from ast century for 30 years and there had stored more than two million tons of uranium tailing sand in it.So it is very significant to find out the spatial distribution and pollution status of U,Mn,As,Pb,Cr and how uranium tailings effect the soil around it.Based on sampling and detecting in the wild,this paper statistics the data of elements by using SPSS software.It is fiting the best modle by the calculation of GS+7’s semivariable function;Based on those modles and it makes spatial distribution map of elements by using the ordinary kriging.The results of assessment will be more accurately by comparing the assessment of single factor contamination index method and geoaccumulation index method.The paper takes the Nemerow multi-factor pollution index method to assessment 5 elements in the soil of study aera comprehensively.The main contents and results of this paper are as followed:1 The content of 5 elements in the soil of study area didn’t coincided with normal distribution with larger span and big variation coefficients.The arge proportion of soil sample content are more then the soil background value by comparing the soil background value of China and the soil background value of Hunan province.2 The calculation results of semivariable function GS7+ indicate of that:optimal model of U and As is Gaussian model,optimal model of Mn,Pb and Cr are exponential model;the value of C0+C/CO show that U and As are middle spatial correlation patterns,while Mn,PbandCrare strong spatial autocorrelation.Based on above results,it is using the ArcGIS to make the spatial distribution maps of 5 elements.3 The result of single factor contamination index method indicated that the soil heavily contaminated by U focus on the 200m area around the uranium tailing;the Mn and As exceed standard soil distributed in southeast of study area;the Pb slightly exceed standard soil distributs most widely;the Cr slightly exceed standard soil around the south,east,north of uranium tailing and the southeast of study area.The result of geoaccumulation contamination index method indicated that the other three elements are non-pollution except U and As.The result of Nemerow multi-factor pollution index method indicated that heavily contaminated soil distributed in the surrounding of uranium tailing and the southeast of study area.