Study On Spatial Variability And Pollution Evaluation Of Heavy Metal In Rare Earth Mining Soil Based On GIS

Mining often leads to serious environmental problems,and it is also a major source of soil heavy metal contaminants.Xinfeng county is a county under the jurisdiction of Ganzhou city in Jiangxi Province,mineral resources is rich,species are diverse,but because of early mining technology backward,as well as let out three wastes unreasonably,resulting in soil heavy metal content exceeded,seriously damaged surrounding ecological environment.This paper was in view of the environmental problems existing in mining a rea,selecting K iln under mining?C higang mining?mud pit mining and Hushan mining as the research area,conducting three main steps,firstly locating collection sample points by GPS,and the dates were processed,the content characteristics of heavy metals was analyzed,secondly choosing the optimal interpolation model for each heavy metal among Kriging interpolation,inverse distance weighted interpolation,global polynomial interpolation and local polynomial interpolation,and mapping the spatial distribution,finally the single factor index,Nemero comprehensive evaluation and potential ecological risk index were used to evaluate the heavy metals by soil environmental quality standard(GB15618-1995)and soil background value of Jiangxi province,visualizing the results.The main results show that:The average contents of eight heavy metals were 25.973 mg / kg,102.812 mg / kg,64.602 mg / kg,0.053 mg / kg,5.152 mg / kg,54.179 mg / kg,0.051 mg / kg,37.152 mg / kg.From the statistical analysis results can be seen,in addition to Pb other than the 7 elements of the average content had no more than a value.The spatial distribution of heavy metal content shows different distribution patterns,the high content of the kiln mining area was mainly concentrated in the historical heap pool leaching ore field,the upper reaches of the mining area and the Bai Shi Wei River.The high content of C higang mining area was mainly concentrated in the river beside lower house and the historical heap pool leaching ore field.The high content of the mud pit mainly concentrated on historical in situ leaching ore field,historical pond leaching field and farmland near Jiangzi head.The high content of Hushan mining area was mainly concentrated on the historical heap leaching.Heavy metals content in the Hushan mining area were the highest.The background value of soil in Jiangxi Province was taken as the evaluation standard,Pb and N i exceeded the standard,and the mining area was polluted at different degrees.In the evaluation of soil environmental quality,N i and C u exceeded the standard,and the degree of contamination was not significant.The high content of heavy metals were mainly distributed in Hushan mining area,part of Cd and Hg sampling points were in moderate risk level.Generally speaking,the pollution degree of mining area was not big,but the content of some heavy metals was excessive,which should be paid attention to by relevant departments.Hushan mining area was the main pollution area,which may be related to the mining method and transportation of Hushan.