城市路面降雨径流污染特征及源解析的研究进展

Research advance in the characterization and source apportionment of pollutants in urban roadway runoff

城市路面径流是城市地表径流的重要组成部分,因其污染强度大、对地表水体的影响严重而被予以格外的关注。通过对国内外关于路面径流水质的研究进行总结发现:我国城市道路径流中COD、TP、TN和Pb的平均质量浓度分别为239.59、0.46、6.29和0.14 mg·L-1,超过了国家地表水环境质量Ⅴ类标准,TSS的质量浓度高达552.86 mg·L-1。因此,COD、TP、TN、Pb和TSS是我国路面径流的主要污染物。高速路径流污染物Pb、Cu和Zn的浓度明显高于普通道路,而普通道路径流污染物中COD和TSS要高于高速路。与其他国家相比,我国城市道路雨水径流污染物浓度偏高。多数研究表明:污染物的质量浓度与降雨量呈负相关关系,路面坡度增加了车辆与路面的摩擦力和燃料的消耗,进而导致路面径流污染物的浓度较高,路面清扫或许对污染物的浓度有不利的影响,主要由于道路清扫将路面中部分大颗粒破碎,释放出了细小的颗粒物(粒径<43μm)并且不能将其清除的缘故。但是,降雨强度、干期、降雨历时和车流量对径流水质的影响存在一定的争议。通过对现有的研究总结发现:车流量≥30 000的路面径流中COD、TSS、Pb和Cu的浓度是车流量<30 000的路面径流中的2.5、4.3、1.4和5.1倍;路面径流中的重金属主要来源于车辆的交通损耗,有机污染物来源于车辆的交通活动和路面材质,营养污染物来源于大气干湿沉降。今后应从以下几方面开展研究:将多环芳烃、大肠杆菌等水质指标列入研究计划;深入分析影响降雨径流水质的因素及各影响因子间的交互作用;运用同位素溯源技术识别道路径流污染物来源。

As a major part of urban surface runoff, urban road runoff has drawn extraordinary attention due to its large magnitude of pollution and severe influence on surface water bodies. By summarizing the results of previous studies on water quality of road rainfall runoff, it can be found that the concentration of COD, TP, TN and Pb were 239.59, 0.46, 6.29 and 0.14 mg·L-1, respectively, and exceeded the Ⅴ class of surface water. The concentration of TSS was 552.86 mg·L-1. Therefore, the COD, TP, TN, Pb and TSS were the main pollutants of urban road runoff. The concentration of Pb, Cu and Zn are higher in the highway than the other road. But, the concentration of TSS and COD are lower in the highway than the other road. When Comparing domestic studies with the other countries’, the pollutants concentration of road rainfall runoff are higher in China. The most researchers found that the concentration of pollutants and rainfall volume have negative correlation. The steeper slope of the road could produce higher runoff concentrations of pollutants due to the greater friction between vehicle tire and road and more burnt fuel. The road sweeping could have adversely affected to the concentration of pollutants mainly due to releasing the fine material from the fixed load but not having enough suction to remove them. However, there are contradicting reports in the literature as to the correlation of the concentration of pollutants with rainfall intensity, antecedent dry period, rainfall duration and average daily traffic. By summarizing the data in existing studies, it is found that the concentration of COD, TSS, Pb and Cu in road runoff at the traffic volume ≥30 000 were 2.5, 4.3, 1.4 and 5.1 times respectively, compared with the concentration at the traffic volume〈30 000. In the road runoff, the heavy metals were mainly come from vehicle’s exhaust, the organic pollutants mainly sourced from vehicles activities and road material and the nutrition-related pollutants mainly sourced from atmospheric dry and wet deposition. The following aspects should be carried out in future research：To take the polycyclic aromatic hydrocarbons and Escherichia coli into the research program;Deep analysis of the factors affecting rainfall runoff water quality and the interaction between factors, and to utilize the isotope tracing techniques to indentify the pollution source of the urban road runoff.