济南市大气中多环芳烃的污染及致癌风险

Pollution and carcinogenic risk of atmospheric polycyclic aromatic hydrocarbons in Ji'nan

目的了解济南市大气中多环芳烃（PAHs）污染水平，并对其致癌风险进行评估。方法于2013年3—4月采用大气微污染物采样仪在济南市某地采集52组大气样品，用气相色谱一质谱联用仪定量分析16种优控PAHs。结果大气中总PAHs（气相＋颗粒相）浓度范围为6．56～767．02ng／ms，平均浓度为214．54ng／m3；气相PAHs主要以分子量低、易挥发的3环为主，颗粒相PAHs主要以分子量大、不易挥发的5～6环为主。苯并（a）芘只存在于颗粒相中，平均浓度为2．04ng／m3，低于GB3095--2012《环境空气质量标准》二级标准限值（2．5ng/m3）。特征分子比值法和主因子分析法表明燃烧及汽车尾气排放是大气中PAHs的主要来源。颗粒相中以苯并（a）芘为参照的8种分子量≥228的PAHs的致癌等效浓度（TEQ）和致突变等效浓度（MEQ）分别为11．914和9．904ng／m3，分别为单一苯并（a）芘浓度的5．84倍和4．85倍。成人和儿童的PAHs终身致癌超额危险度分别为4．06×10-6和1．77×10-6和。结论本次调查的部分时段大气中PAHs污染较严重，但是根据平均暴露水平估算的人群通过呼吸途径所造成的终身致癌危险度处于正常可接受范围内。

Objective To analyze atmospheric PAHs pollution levels in Ji＇nan and assess carcinogenic risk. Methods The KC-300 atmospheric micro-pollutants sampling instrument was used to collect gaseous samples and panicle samples in the atmosphere of Ji＇nan from March to April, 2013. The concentrations of 16 priority PAHs were determined with GC-MS. Results The average concentration of the total PAHs was 214.54 ng/m3, ranged from 6.56 to 767.02 ng/m3. The gaseous PAHs were mainly composed of 3-ring PAHs （phenanthrene and fluorene were the most abundant compounds）, while the particulate PAHs were largely composed of 5-6-ring. Benzo （a） pyrene mainly existed in the panicle phase, with an average of 2.04 ng/m3, which was lower than the national secondary standard （2.5 ng/m3）. Diagnostic ratio analysis and principal components analysis revealed that the sources of PAHs were mainly from combustion and motor vehicle exhaust emission. Benzo （a） pyrene Carcinogenic equivalent concentration （BaP-TEQ） and mutagenic equivalent concentration （BaP-MEQ） were 11.914 and 9,904 ng/m3 respectively, 5.84 times and 4.85 times as higher as single benzo （a） pyrene. The lifetime cancer risks of PAHs for adults and children were 4.06×10-6 and 1.77×10-6 respectively. Conclusion Atmospheric PAHs in Ji＇ nan has a higher pollution level, but the lifetime cancer risks caused by respiratory pathway exposure is in the acceptable risk level.