Assessment and source analysis of heavy metal pollution in soils with different land use patterns based on GIS

In order to further understand the soil heavy metal pollution status of grassland,cultivated land and construction land in Qitai County,Jimsar County and Fukang City,uses the single factor pollution index,pollution load index and geo-accumulation index method to evaluate the pollution degree of six heavy metal elements such as Zn,Cu,Cr,Pb,Hg and As in soil.Potential ecological risk index,principal component analysis and positive matrix factor analysis(PMF) are used to analyze ecological risk and quantitative pollution sources.The results show that the contents of heavy metal elements in different land use patterns are As>Pb>Zn>Cr>Cu>Hg,and the contents of Pb,Hg and As exceedes the soil background value of Xinjiang,and the accumulation degree is the most serious within the scope of construction land,which exceedes the soil background value of Xinjiang by 4.43,1.50 and 8.23 times higher than those in grassland and cultivated land, respectively. Zn,Cu and Cr are not polluted under different land use patterns.The results of single factor pollution index and geo-accumulation index show that the pollution of Pb,Hg and As is relatively serious,showing light-intensity pollution level,and the pollution of Zn,Cu and Cr is light-moderate pollution level.The pollution load index of the whole study area ranged from 0.99 to 2.57,which is light pollution level.The potential ecological risk index of heavy metals in soil under different land use patterns is Cu,Pb,Hg and As,which reached a very strong pollution level.The pollution sources of principal component analysis and PMF model show that Zn,Cu and As are not only mainly affected by soil parent materials,but also affected by industrial pollution activities.Cr is mainly affected by soil parent material.Hg and Pb are greatly affected by industrial production and frequent human activities.The contents of Pb,Hg and As in different land use patterns are generally higher than the background values,and the pollution is the most serious.