兰州市土壤中PAHs和PCBs的分布特征及风险评价

Distribution Characteristics and Risk Analysis of PAHs and PCBs in Soils of Lanzhou

通过采集兰州市各功能区表层土壤样品,分析土壤中PAHs和PCBs的分布特征及潜在风险。结果表明,兰州市土壤中16种PAHs的平均质量比为5 734μg/kg,其中7种致癌芳烃的平均质量比为276μg/kg;18种PCBs的平均质量比为45.9μg/kg,其中7种指示性PCBs的平均质量比为10.8μg/kg。风险评价结果表明,除苊为高生态风险外,兰州市土壤中PAHs其他组分和PCBs均处于低中生态风险。16种PAHs的毒性当量浓度为59.9μg/kg,主要贡献者为苯并[a]芘和苯并[b]荧蒽;7种指示性PCBs的毒性当量浓度为1.96×10^(-4)μg/kg,主要贡献来源为PCB138和PCB118。

In order to investigate the distribution characteristics and potential risks of polycyclic aromatic hydrocarbons(PAHs)and polychlorinated biphenyls(PCBs)in soils of Lanzhou,topsoil samples were collected from different functional zones.Results showed that the average mass ratio of 16 PAHs was 5 734μg/kg,in which the average value of 7 carcinogenic PAHs was 276μg/kg.The average mass ratio of 18 PCBs was 45.9μg/kg,in which the average value of 7 indicator PCBs was 10.8μg/kg.Ecological risk assessment showed that except for acenaphthene,which was at a high ecological risk level,other components of PAHs and PCBs in soils of Lanzhou were all at low or moderate risk level.The toxicity equivalent concentrations of 16 PAHs was 59.9μg/kg,benzo[a]pyrene and benzo[b]fluorathene were the mainly contributors.The toxicity equivalent concentrations of 7 indicator PCBs was 1.96×10-4μg/kg,PCB138 and PCB118 were the main contributors.