科教园区绿地土壤环境质量关系到在其中学习、工作和生活的学生和教职员工的身体健康.本研究对多环芳烃(PAHs)在科教园区绿地土壤中的累积特征、主要来源、潜在健康风险及其与土壤有机质(SOM)的相关关系进行了分析.共采集了北京市城区20所学校和研究机构中的绿地土壤,使用自动索氏-固相萃取-GC/MS联用技术分析了16种PAHs在其中的残留水平.结果表明16种PAHs总浓度范围为194~6 988μg.kg-1,平均值为1 637μg.kg-1.中、高环的PAHs(4~6环)占到了总PAHs浓度的85%.源解析结果显示其主要来源是科教园区内部冬季供暖和食物供应过程中所燃烧的煤.聚类分析显示NAP与其余15种PAHs组份在来源方式上存在明显的区别.除NAP以外,其余15种PAHs含量与土壤有机质之间没有相关关系,推测这15种PAHs组份主要来源于近距离源的一次沉降.北京市科教园区绿地土壤PAHs对生活在其周围的人群产生的终生致癌风险较小,但其间接影响不容忽视.
Pollution of green space by polycyclic aromatic hydrocarbons(PAHs) in education area may pose a potential impact on the faculty,students,and staffs.To study the characterization,influencing factors,sources and risks of soil PAHs in Beijing educational areas,the concentrations of 16 priority PAH identified by United States Environmental Protection Agency(USEPA) in green spaces of 20 schools and academies were determined.The total PAHs concentration ranged from 194 μg·kg-1 to 6 988 μg·kg-1,with a mean of 1 637 μg·kg-1.Middle and high molecular weight PAHs(4-6 rings) accounted for 85% of the total PAHs concentration.Coal combustion for winter heating and food supply were the main sources of PAHs in Beijing educational areas.Based on the Cluster analysis,the transportation and accumulation of NAP were distinguished from other 15 PAH congeners.No significant correlation between PAHs and soil organic matter(SOM) was found except for NAP,suggesting that most of the PAH congeners were derived from direct deposition of urban sources.The integrated lifetime cancer risks(ILCRs) associated with exposure to soil PAHs in Beijing educational areas were acceptable,but the indirect effects should not be ignored.