安徽太平湖流域底质沉积物多种重金属和砷的分布特征及环境评价

Distribution Patterns of Heavy Metals in Surface Sediments and Environmental Quality Assessment on the Taipinghu Basin of Anhui Province

对安徽太平湖湖区和5条主要入湖河流表层沉积物中的重金属Cu,Pb,Zn,Cd,Cr,Hg和As的含量水平和空间分布进行分析,并对沉积物中重金属对生态环境的影响进行评价.结果表明,湖区重金属Cu,Pb,Zn,Cd和Hg的平均含量分别为21.25,0.96,14.61,0.034,0.005mg/kg,Cr和As低于检出限.各重金属在湖区的空间分布较为一致,整体上呈现自西向东重金属含量先变高再变低的趋势,5条入湖河流的重金属含量均低于黄山市土壤背景值.潜在生态风险(Hakanson)评价结果表明,所有点位的单因子重金属潜在生态风险值Eri均低于40,生态综合风险指数(RI)全部低于150,研究区整体处于轻微生态风险水平.地累积指数评价结果表明重金属元素在表层沉积物中基本不构成污染.沉积物质量基准法得出重金属浓度均低于ERL值,对研究区域生态环境无影响.底质沉积物中的重金属富集尚未对流域的生态环境造成不良影响,太平湖湖区和5条主要入湖河流生态环境状况良好.

The concentration of seven heavy metals in the surface sediments from Taipinghu Lake and five riverswhich inflow into lake in Anhui Province were determined. Their distribution and contamination status arediscussed. The average content rations ofCu, Pb, Zn, Cd, Hg were 21.25, 0. 96, 14. 61, 0. 034, 0. 005 mg/kg,while Cr and As are below detection limit. The ecological risk assessment in this area is carried out by the methodsof geoaccumulationindex, ecological risk index and sediment quality guild. The results show that heavy metalexcept Cu concentrations in lake region and inflow rivers are lower than soil background values in Huangshan.According to the value of El and RI, all sites of value of Eri are lower than 40 and the value of RI are lower than150 indicate that the study area is under light potential ecological risk, and the value of Igoalso shows the degree ofsurface sediments in Taipinghu are not serious. The accumulative contents of Cu exhibited moderate contaminationbased on geoaccumulation index while SQGs show the concentration of Cu is not harmful to organisms, the value ofSQGs also show the rest of heavy metals are below ERL which means the environment of study area is appropriatefor creatures. Pollution to environment was not distinguished from accumulation of heavy metals in surfacesediment environment.