中文摘要：

为明确北京东南郊灌区表层土壤和农作物多环芳烃（PAHs）含量及污染水平,2015年在该灌区采集了31个土壤样品和38个作物样品,采用气象色谱-质谱仪分析了样品中16种优先控制PAHs含量。研究结果表明灌区表层土壤16种PAHs总量为113.5～449.8μg/kg（均值为258.5μg/kg）,与荷兰土壤环境质量标准相比,本研究表层土壤中相应10种PAHs的总量为83～307μg/kg,土壤10种PAHs的苯并（a）芘毒性当量浓度均值为19.0μg/kg,灌区土壤总体上受到PAHs轻度污染,但土壤PAHs含量远低于荷兰土壤环境质量标准中的干预值,土壤PAHs潜在生态风险不显著。小麦籽粒、玉米籽粒和蔬菜PAHs含量分别为368.7～389.9、87.7～113.5、51.8～291.8μg/kg。粮食作物籽粒PAHs主要以苯并（g,h,i）苝为主,蔬菜PAHs以菲含量最高。粮食作物籽粒苯并（a）芘含量均低于食品安全国家标准限值。燃烧源是土壤和粮食作物PAHs主要污染源,而蔬菜PAHs主要污染源为燃烧源和石油源混合来源。成人和儿童PAHs致癌风险分别为4.02×10^（-5）和1.76×10^（-5）,非致癌指数分别为2.72×10^（-2）和4.78×10^（-2）,均低于US EPA相应标准参考值。人体健康风险主要暴露途径和介质是口-作物,对致癌风险贡献最大的组分为苯并（a）芘和二苯并（a,h）蒽,对非致癌风险贡献最大的组分是苯并（g,h,i）苝和菲。

英文摘要：

Wastewater irrigation was adopted in irrigation district in southeastern suburb of Beijing from 1950s to 2003, the main source of wastewater was industrial and domestic wastewater from Beijing. Reclaimed water was used for irrigation since 2003 in the irrigation district. To investigate the residual levels of polycyclic aromatic hydrocarbons （PAHs） in topsoil and crops in the irrigation district, totally 31 samples of soil and 38 samples of crops were collected, and the concentrations of 16 US EPA （United States Environmental Protection Agency） priority PAHs were determined by gas chromatography equipped with a mass spectrometry detector （GC- MS） in 2015. Results showed that the PAHs in topsoil in the district were ranged from 113.5 μg/kg to 449.8 μg/kg, with a mean value of 258.5 μg/kg. And 80% of the collected soil samples were slightly polluted by PAHs. The sums of 10 PAHs were 83 -307 μg/kg, which were lower than the standard of Netherlands （the intervention value was 40mg/kg）. The average value of hap toxic equivalence quantity （TEQBap） for 10 PAHs in topsoil was 19.0 μg/kg, which was lower than the standard of Netherland （33.0 μg/kg） , indicating that there was no remarkable potential ecological risk. The concentrations of winter wheat grain, summer maize grain and vegetables were 368.7 389.9 μg/kg, 87.7 - 113.5 μg/kg and 51.8 ~ 291.8μg/kg, respectively. Benzo （ g, h, i） perylene wasthe dominant component in winter wheat grain and summer maize grain, which accounted for 36. 6% ~ 41.6% of the 16 PAHs concentrations. For vegetables, the highest individual PAH was phenanthrene, which represented 24.0% of the 16 PAHs. The concentrations of benzo（a）pyrene in cereal grains were lower than the Chinese standard limits of 5 μg/kg in food. The high temperature combustion was the major pollution source for PAHs in topsoil and cereal grains, while the mixed sources of fossil fuel combustion and oil source were the pollution source for PAHs in vegetables. The carcinogenic risk o