北京城区屋面径流中PAHs的污染特征与来源解析

以北京典型城区屋面径流中的PAHs为研究对象,在2008年雨季采集了不同地点的屋面径流,分析了溶解相和颗粒相PAHs的质量浓度,对屋面径流中PAHs的质量浓度特征、时空变化规律及来源进行了讨论。结果表明,屋面径流具有较严重的PAHs污染,16种PAHs在溶解相中的总质量浓度为563.85~937.01 ng.L-1,来源主要是机动车排放（31.9%）、煤燃烧（39.6%）、天然气燃烧（15.3%）及石油类的挥发（14.2%）;在颗粒相中的总质量浓度为844.48~1372.62 ng.L-1,来源主要包括燃煤（51.8%）、汽油（38.1%）和柴油（10.1%）的燃烧等。BaP的EMC平均值（172 ng.L-1）远远超过我国污水排放标准（30 ng.L-1）,且以颗粒相为主。不同地点采集的屋面径流中的PAHs质量浓度大部分表现出较明显的初期效应和时间变化,而在不同采样点之间则没有明显的空间差异。

Concentration characteristics and source identification of PAHs in urban roof runoff in Beijing

Roof runoff samples were collected at different sampling sites in Beijing during the raining season in 2008.The samples were analyzed for PAHs in both dissolved and particle phases.The concentration characteristics,temporal and spatial variations and sources of PAHs were investigated.The results showed that PAHs concentrations in dissolved phase ranged from 563.85 to 937.01 ng·L-1.The PAHs in dissolved phase originated mainly from vehicle emission（31.9%）,coal combustion（39.6%）,natural gas combustion（15.3%） and oil spill（14.2%）.PAHs concentrations in particle phase ranged from 844.48 to 1372.62 ng·L-1.The PAHs in particle phase were mainly from coal（51.8%）,gas（38.1%） and diesel（10.1%） combustion.The average EMC value of BaP（172 ng·L-1） was much higher than the applicable wastewater discharge standard of China（30 ng·L-1）.Significant first flush effect of PAHs concentration was observed in the study,and no spatial variation was seen.