| With the overexploitation and utilization of mineral resources,the ecological environment around the mining area has been seriously damaged,especially the heavy metal pollution of the soil,which directly affects the health of local residents.In this paper,the main living area(key area)of Tan jiashan coal mine is taken As the research area to study the geochemical characteristics and pollution degree of nine heavy metal elements in the research area,namely As,Hg,Cd,Pb,Cr,Cu,Ni,Zn and Mn.By studying the correlation between soil physical and chemical properties and heavy metal elements,the relationship between soil properties and heavy metal elements was expounded.According to the analysis methods of multivariate statistical analysis,spatial analysis and principal component analysis,combined with SPSS,ARCGIS and other software,the sources of heavy metals in soil in the study area were expounded from multiple perspectives.The single factor index method,Nemerow pollution index method and geo-accumulation index method were used to evaluate the soil pollution status of 9 heavy metals in the study area.The main conclusions are as follows:1.The average contents of Cd,Cu,Pb,Zn,As,Cr,Ni,Hg and Mn in the soil of the study area were 4.89 mg/kg,55.56 mg/kg,0.87mg/kg,120.12 mg/kg,18.18 mg/kg,112.13mg/kg,37.36mg/kg,0.22 mg/kg and 5.74mg/kg respectively.Coefficient of variation were 15.66,2.32,0.90,0.46,0.46,1.17,1.16,0.18,0.63,the relative national soil background values and enrichment coefficient of EF were 5.50,2.32,0.04,1.77,1.82,1.73,1.51,5.5,11.04,there are eight kinds of heavy metal element content is significantly higher than the background values,the highest degree in Cd element enrichment and the EF values is 54.32 times the national soil background value,followed by Mn element,Its EF value is 11.04 times of the national soil background value,and the enrichment coefficient of Cu,As,Zn,Cr and Ni is also more than 1 times of the national soil background value.The frequency distribution of Pb,Cd,Hg and Zn is relatively concentrated,and the fitting curve is close to normal distribution,with few extreme values and outliers in the box diagram.However,the frequency distribution of the other five heavy metal elements does not conform to normal distribution,and the box diagram also shows a trend to the right obviously,with more extreme values and outliers.2.The dispersion degree of heavy metal elements(As,Cd,Cu,Ni and Mn)in the soil of the study area is relatively high.Cd and Mn are generally enriched compared with the national soil background value.The dispersion degree of Cr,Hg,Pb and Zn is low,which is similar to the national soil background value,and the spatial distribution of the high value is relatively scattered.3.surface soil heavy metal pollution condition in the study area,the evaluation results show that the entire study area,As,Hg,Pb,Cr,Cu,Ni,zinc and Mn,the eight heavy metals are still clean degree,only the Cd element pollution is especially significant in the study area,so in order to improve the present situation of pollution,we suggest that the relevant departments of the attention and strengthen the management and control of local elements Cd pollution.4.heavy metal element content in the research area is obtained by analysis of crops high heavy metal element As Pb and Cd,and its corresponding root in the soil heavy metal element content is higher for Cd,zinc,and As the three elements,heavy metal pollution in soil and no damage to the crops,shows no obvious correlation between them. |
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