基于城镇化进程表层土壤多环芳烃来源解析及风险评价

Sources and Risk Assessment of Polycyclic Aromatic Hydrocarbons from the Urbanization Process of Topsoil

为研究城镇化进程对土壤PAHs残留状况、来源以及健康风险的影响,采集辽宁地区95个表层土壤样品,利用气相色谱-质谱联用仪分析21种PAHs含量.结果表明研究区域中,背景点、沈抚新城、沈阳以及抚顺内Σ21PAHs总含量分别为1 496.76、3 000.50、8 705.11以及8 178.90μg·kg-1,即城镇化程度与PAHs含量呈正相关关系.利用分子比值法与PMF模型进行来源分析,结果表明研究区域表层土壤PAHs来源主要为煤燃烧源与交通源(石油燃烧),其中4个区域的主要来源依次为石化燃烧源41.0%、煤柴等生物质燃烧源64.4%、交通源67.5%以及交通源62.0%,即随着城镇化进程推进,人为源(主要是交通源)逐渐成为环境中PAHs的主要贡献者.健康风险评价表明,通过土壤误食与皮肤接触途径暴露致癌风险水平较高,城市土壤PAHs存在较高的健康风险,且儿童与青少年受到的健康风险较大,需要引起注意.

To study the effects of urbanization on concentration,sources,and health risks of polycyclic aromatic hydrocarbons（ PAHs）,95 topsoil samples were collected from Liaoning Province. For this assessment,21 PAHs were analyzed via gas chromatography-mass spectrometry and discussed. The results show the total concentrations of the 21 PAHs in background,Shen-Fu,Shen-Yang,and Fu-Shun were 1 496. 76 μg·kg-1,3 000. 50 μg·kg-1,8 705. 11 μg·kg-1,and 8 178. 90 μg·kg-1,respectively,which is positively correlated with the urbanization levels. Diagnostic ratios and PMF modal analysis indicate that the sources of the PAHs in soils were most likely coal combustion and traffic combustion（ petroleum combustion）. The main sources of PAHs in the four areas were petrochemical combustion（ 41. 0%）,coal combustion（ 64. 4%）,traffic combustion（ 67. 5%）,and traffic combustion（ 62. 0%）,that is,with the urbanization process,human activity（ mainly traffic combustion） gradually become the major contributor of PAHs to the environment. Health risk assessment showed that the risk of cancer exposure through soil digestion and skin exposure was higher. There is a higher health risk from PAHs in urban soils,and the health risks associated with children and adolescents are greater than with other residents,requiring more attention.