Spatial Distribution Characteristics And Risk Assessment Of Heavy Metal Pollution In Soil In Hefei Ecological Park

Heavy metal pollution in soil is one of the most popular researches now.It plays a key role in the environmental quality and safety of soil and the protection of human health.In this paper,the heavy metal in the surface soil of Dawei Ecological Park in Hefei of Anhui Province was taken as the research object,and 170 sample data were collected to detect and analyze the content of Cu,Cd,Mn,Zn,Pb and Cr.The characteristics,sources,influencing factors and spatial distribution characteristics of heavy metal pollution in soil are obtained by using the combination of multivariate statistical methods and geostatistical methods;the pollution risk assessment method is used to evaluate the pollution status of heavy metals in soil,and the evaluation results are analyzed.The main research results of this article are as follows:(1)According to the detected results of the six heavy metal elements in the top soil,the average concentration of Cu and Cd exceeds the soil background value of Hefei City,Anhui Province,which are 1.035 and 27.85 folds higher than the background value,respectively.The coefficients of Cd,Cu,and Pb are 1.371,0.423,and 0.374,respectively,which are highly variable.The results show that the distribution of those heavy metals is relatively uneven due to the human activities which can lead to the high variability.The average geoaccumulation index of Cd in heavy metal elements is 3.282,which is more serious in the evaluation of pollution level according to the analysis of geoaccumulation pollution index method.The remaining five heavy metals have a cumulative index value of less than 0,which indicating that there is no cumulative pollution.And through the comparative analysis of the pollution analysis on both sides of the road and away from the road,the concentration of Mn and Zn elements is almost the same in the comparative analysis.while the heavy metal concentrations of Cr,Cu,Pb and Cd in the samples on the road side are higher than that in the samples collected farther away from the road.(2)Correlation analysis of heavy metal elements in soil shows that the first main component is mainly considered to be human influences such as transportation and pesticides and fertilizers.The second main components,Mn and Zn,are mainly considered to be influenced by natural factors such as parent materials.In terms of spatial distribution characteristics,the spatial distribution of various heavy metal elements in the study area is still significantly different,and the high-value areas are mainly island-shaped.The high value area of Mn element is mainly distributed in the north of the study area;the high value area of Zn element is distributed in the northwest of the study area,and the second highest value area is distributed in the north of the study area;the high value areas of Cd and Cr are mainly distributed in the northeast and southeast of the study area;the high value area of Cu element is mainly distributed in the south and northwest of the study area;the high value area of Pb element is mainly distributed in the northwest and southeast of the study area.In summary,most of the high-value areas of heavy metals are distributed in the northern part of the study area,followed by the southeastern area.(3)From the single pollution index method,it is known that Mn,Zn,Pb,and Cr are currently in a relatively minor pollution impact situation,but the single pollution index of Cu and Cd elements is higher than I and the pollution degree is relatively higher.The evaluation result of the Nemerow index evaluation method indicates that the average value of the Nemerow pollution index is 0.67,which in the range of the safety evaluation result.The number of samples in the warning limit still occupies the majority,and the proportion of the number of collected samples is up to 90.59%.According to the analysis of potential ecological risk assessment,the average potential ecological risk factor of Cd element is higher than 160,which has a strong potential ecological risk.The average potential ecological risk factors of remaining heavy metal elements Cu,Mn,Zn,Pb,Cr are 5.18,0.42,0.93,3.70,1.69,respectively,which are all less than 40 and belong to the low ecological risk levels,indicating that Cd is a key ecological risk factor in the study area.Through the analysis of multiple heavy metal elements,the average value of the comprehensive ecological risk index of heavy metals in the study area is 297.42,which is a moderate potential ecological risk.