合肥市生态园区土壤重金属空间差异分析及生态风险评价

Spatial Difference Analysis and Ecological Risk Assessment of Soil Heavy Metals in Ecological Park of Hefei City

为了研究土壤重金属含量在城市生态园区的空间分布特征及其潜在生态风险,以合肥市大圩生态园区为研究区,共采集75组生态园区土壤样品。采用电感耦合等离子体发射光谱仪(ICP)与手持式XRF元素分析仪测定了样品中重金属Pb、Cd、Cu、Cr、Zn、Mn的含量。采用潜在生态危害指数法对大圩生态园进行生态风险评价,并采用多元统计法、反距离权重插值方法,分析了土壤中各重金属元素之间的相关性和空间分布特征。结果分析得到,研究区土壤中Cu、Cd、Mn、Zn、Pb、Cr的平均含量分别为30.93、3.55、334.35、48.64、19.81、72.41 mg kg-1,其中Cu、Cd、Cr高于中国土壤背景值,土壤重金属的综合生态风险指数平均值低于150,属于低生态风险。多元统计分析结果显示,公路交通所带来的污染物对Cu、Cr、Pb这3种元素影响较显著,Mn和Zn来源相似,主要受自然因素的影响。Mn、Zn的主要富集地区为研究区的北部,Cr、Cd的主要富集地区均处于研究区的东南和南部,Cu的主要富集地区为研究区的西北部与南部,Pb的主要富集地区处于研究区的西部和东南部。

In order to study the spatial distribution characteristics of soil heavy metal content in urban ecological parks and its potential ecological risks,a total of 75 sets of ecological park soil samples were collected from Hefei Dawei Ecological Park.The contents of heavy metals Pb,Cd,Cu,Cr,Zn and Mn in the samples were determined by inductively coupled plasma optical emission spectrometry(ICP)and hand-held XRF elemental analyzer.The ecological risk assessment of Dawei Ecological Park was carried out by using the potential ecological hazard index method.The correlation and spatial distribution characteristics of various heavy metal elements in soil were analyzed by multivariate statistical method and inverse distance weight interpolation method.The results showed that the average contents of Cu,Cd,Mn,Zn,Pb and Cr in the soil of the study area were 30.93,3.55,334.35,48.64,19.81 and 72.41 mg·kg^-1,respectively,among which Cu,Cd and Cr were higher than the background values of China soils,and the comprehensive ecological risk index of soil heavy metals is less than 150,which is a low ecological risk.Multivariate statistical analysis showed that the pollutants brought by highway traffic had significant effects on Cu,Cr and Pb.The sources of Mn and Zn were similar,mainly affected by natural factors.The main enrichment areas of Mn and Zn were located in the northern part of the study area.The main enrichment areas of Cr and Cd were located in the southeast and south of the study area.The main enrichment areas of Cu was located in the northwest and south of the study area,The main enrichment area of Pb was located in the west and southeast of the study area.