不同屋面雨水径流中PAHs污染特性对比分析

对南京市典型沥青屋面、瓦屋面径流中PAHs含量进行了9场降雨事件的现场取样监测,对比分析了2种不同屋面径流中PAHs的EMC值及其各组分的浓度,并对其初期效应及影响因素进行了分析和探讨.结果表明,沥青屋面径流PAHs污染较严重,其平均浓度为4 261.7 ng/L,而瓦屋面径流PAHs平均浓度仅为351.2 ng/L.沥青屋面、瓦屋面径流中PAHs均以4环组分为主,沥青屋面径流中3环组分占较大含量,而瓦屋面径流中5环和6环PAHs浓度仅次于4环PAHs.大多数降雨事件中总PAHs及各组分均存在较显著的初期效应；前期晴天数对PAHs在屋面的累积影响最大,瓦屋面径流PAHs含量受降雨强度影响较大,而沥青屋面径流PAHs含量受降雨量影响较大.

Comparison and analysis characteristics of PHAs pollution for different types of roof runoff

PAHs content in the runoff of two different types of roofs in Nanjing were monitored through the field sampling during 9 rainfall events.The EMCs(event mean concentration) and PAHs(polycyclic aromatic hydrocarbons) composition were analyzed and compared,and then the first flush effect and the influential factors were discussed.The results show that the PAHs pollution in asphalt roof runoff is more serious.The average EMC value of PAHs in asphalt roof and tile roof runoff are 4 261.7,351.2 ng/L,respectively.The main component of PAHs in both roof runoffs is 4-ring PAHs,3-ring PAHs in asphalt roof runoff also account for a large proportion,while 5-ring and 6-ring PAHs in tile roof runoff are only slightly less than 4-ring PAHs.Total PAHs and relevant components exhibit a pronounced first flush effect in most rainfall events;Correlation analysis suggests that the antecedent dry period is the most significant influential factor for PAHs accumulation on the roof,and the PAHs content in tile roof runoff is mainly influenced by rainfall intensity,while the PAHs content in asphalt roof runoff is mainly influenced by rainfall quantity.