DiBlasi Catherine J, Li Houng, Davis Allen P, Ghosh Upal
Department of Civil and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland 21250, USA.
Environ Sci Technol. 2009 Jan 15;43(2):494-502. doi: 10.1021/es802090g.
This research investigated the removal and fate of 16 USEPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) from urban stormwater runoff through a bioretention cell. Bioretention is an infiltration/filtration practice containing a mixed layer of about 90 cm of soil, sand, and organic matter, planted with appropriate vegetation. Field water quality monitoring and bioretention media core analyses were performed. The results indicate that bioretention is a promising management practice to control runoff PAH pollutants. The PAH event mean concentration (EMC) reduction ranged from 31 to 99%, with a mean discharge EMC of 0.22 microg/L. The mass load decreased from a mean value of 0.0180 kg/ha yr to 0.0025 kg/ha yr, suggesting an average PAH mass load reduction of 87% to the discharging watershed. The most dominant PAH species monitored were fluoranthene and pyrene. Influent PAHs indicated strong affiliation with runoff total suspended solids (TSS). As such, PAH removal positively correlated with TSS removal. Low rainfall depth was associated with high influent PAH concentration and resulted in favorable PAH removal. Source investigation suggested that the PAHs measured in the monitored cell were from pyrogenic sources, likely resulting from vehicle combustion processes. Sealers used in parking lots and driveway coatings were also a possible source of PAHs. Media core analyses indicated that the intercepted PAH compounds transported only a few centimeters vertically in the soil media near the runoff entrance location, suggesting that a shallow cell design may be adequate for systems focusing on PAH removal.
本研究调查了通过生物滞留池去除城市雨水径流中16种美国环境保护局优先污染物多环芳烃（PAHs）及其去向。生物滞留是一种渗透/过滤措施，包含约90厘米厚的土壤、沙子和有机物质的混合层，并种植了适宜的植被。进行了现场水质监测和生物滞留介质芯样分析。结果表明，生物滞留是控制径流PAH污染物的一种很有前景的管理措施。PAH事件平均浓度（EMC）降低幅度为31%至99%，平均排放EMC为0.22微克/升。质量负荷从平均值0.0180千克/公顷·年降至0.0025千克/公顷·年，表明向排放流域的PAH平均质量负荷降低了87%。监测到的最主要PAH种类是荧蒽和芘。进水PAHs与径流总悬浮固体（TSS）有很强的相关性。因此，PAH去除与TSS去除呈正相关。低降雨深度与高进水PAH浓度相关，并导致良好的PAH去除效果。源调查表明，监测池中测得的PAHs来自热解源，可能源于车辆燃烧过程。停车场和车道涂层中使用的密封剂也是PAHs的一个可能来源。介质芯样分析表明，截留的PAH化合物在径流入口位置附近的土壤介质中仅垂直移动了几厘米，这表明对于专注于PAH去除的系统，浅池设计可能就足够了。
