台州市路桥农业土壤中重金属的污染分析

摘要

通过采集浙江省台州市路桥区土壤样品,对其中重金属的污染水平、来源进行探讨,并进行生态风险评价.采用电感耦合等离子体发射光谱法(ICP-AES)定量分析台州路桥38个土壤中Cu、Pb、Ni、Ag、As、Cd、Zn、Sn、Sb和Hg的含量,与《土壤环境质量标准》(GB15618-1995)中二级标准相比,Cd超标最严重,超标率为89.5％,其次是Hg和As,超标率分别为57.9％和39.5％.对10种重金属的变异系数进行比较,Cu、Zn、As、Sb和Sn的值大于1,表明这5种重金属受到较强的人类活动干扰.内梅罗综合污染指数评价表明路桥地区63.2％的土壤受到重金属中度污染以上.因子分析法进行的源解析表明:路桥土壤中金属主要来源于人类的工业和农业活动.利用地积累指数法对金属的生态风险评价表明,路桥土壤中10种重金属的污染程度由强至弱依次为:Cd ＞Hg＞Cu＞Ag＞Sb＞Zn＞As＞Pb≈Sn＞ Ni.采用潜在生态危害指数法计算路桥土壤中7种金属的潜在生态危害系数(Ei)和潜在生态危害综合指数(RI),结果表明,路桥土壤中7种重金属生态危害系数均值为190.9,为中等生态危害,Hg、Cd和Cu是主要的生态危害因子,应该受到重视.%The soil samples,collected from Luqiao,Taizhou,Zhejiang,were studied for the heavy metal pollution levels,sources and assessment of ecological risk.The concentrations of heavy metals including Cu,Pb,Ni,Ag,As,Cd,Zn,Sn,Sb and Hg in 38 soil samples were analyzed by Inductively Coupled Plasma-atomic Emission Spectrometry (ICP-AES).And 89.5％ of Cd,followed by Hg and As,exceed 57.9％ and 39.5％ respectively compared with level 2 of China Soil Environmental Quality Standards (GB15628-1995).The comparison of the variation coefficient of the 10 heavy metals showed that Cu,Zn,As,Sb and Sn were strongly affected by human activities for their value were greater than 1.The result of Nemerow pollution exponential evaluation indicated that 63.2 ％ of soils in Luqiao were medium level pollution.The factor analysis showed that source of metal in the soil comes mainly from industrial and agricultural activity of human.The pollution extent of heavy metals in soil by Geo-accumulation Index (Igeo) followed the order:Cd＞Hg＞Cu＞Ag＞Sb＞Zn＞As＞Pb≈Sn＞Ni.The potential ecological risk of 7 heavy metals in soils evaluated by the potential ecological risk factors indicated that the mean value of potential ecological risk factor was 190.9,which was medium ecological risk.According to the potential ecological risk indexes (RI) of 7 heavy metals at all sampling sites,Hg,Cd and Cu are the main ecological risk factors,should be treated seriously.