| In recent years, with the development of economy and urbanization, human activities have a negative impact on the ecological environment and ecological cycle, resulting in the increase of urban non-point source pollution. Some toxic and harmful pollutants which were difficult to degrade distributedwidely and increased, leadto great threat to human life and health. PAHs is a typical persistent organic pollutants due to its strong carcinogenic, teratogenic, the mutation of mutagenic effect, and exists widely in environment and long distance migrationwhichhave potential negativeinfluenceon ecological environment security. Based on the US EPA priority control of 16 kinds of PAHs as the research object in this paper,samples were analyzed for PAHs in roof and road runoff,including pollution characteristics,dynamic variation and first flush effect. Sources apportionment of PAHswere identifiedbased on characteristic ratios,principal component analysis and PMF model in the. Ecological risk assessment and management control measures in the urban rainfall runoff were also discussed.There are differences between the different types of roof runoff pollution characteristics of PAHs, tile roof runoff samples in the concentration of PAHs highest asphalt roofing is the lowest. Due to the different rainfall characteristic parameters lead to pollutants concentration in different rainfall events have differences, the 2014-05-11 incident of runoff pollutants concentration in the lowest. From the PAHs components, the main constituent of the roof runoff samples is 4 ring. The content of PAHs in roof runoff during rainfall fluctuations are consistent, showing the basic characteristics of the concentration attenuation effect.The first flush effect is not happened in each rainfall events, the FFE of PAHs in roof runoff is weak or not obvious.There are differences in the PAHs content in the surface runoff of various underlying surfaces, and the road runoff showed variation Lincang road> Dongchuan road> parking lot. the main components of PAHs in road runoff is 4 ring.3 kinds of road runoff PAHs all showed significant first flush effect, but there are differences in rainfall intensity between various underlying surfaces. The different components of PAHs and TOC show marked positive correlation, so was TSS. The values of partition coefficient Kp in road runoff samples changed from 1.16×104～1.71×106L·kg-1. The PAHs of road runoff were mainly derived from dust and wet deposition, which contributes greatly to the dust, while the wet deposition contributes to the low and middle rings PAHs in runoff.PAHs pollution load of roof runoff was influenced by factors including rainfall characteristics, pollutants accumulation, characteristics of watersheds and the type of underlying surfaces, etc. Comparison of roof and road runoff pollutants in pollution load, can clearly see road runoff is greater than that of roof runoff, which primarily related to pollutant sources. Roof runoff pollutant source is single, and road runoff sources is extensive and complicated.With the characteristic ratio method conducted pollutants in rainfall runoff, the source apportionment showed that PAHs in rainfall runoff mainly from combustion sources, PAHs in load runoff came from incomplete combustion of grass, wood and coal combustion, oil combustion also made a small contribution; By PMF and PCA-MLR model for quantitative analysis of the sources of PAHs in the runoff, the major source of PAHs in roof runoff was vehicle emissions, coal combustion and oil volatilization, the main sources of PAHs in the load runoff was coal combustion, oil spills, gasoline combustion and diesel combustion sources.PAHs ecological risk assessment of rainfall runoff show that the TEQ concentration of roof runoff was 9.22～16.86ng/L, while 9.22～16.86ng/L in road runof, and concentration are more than our emissions standards. If the runoff directly into water will inevitably cause urban water pollution, so the conctol of pollutant in the rainfall runoff can not be ignored. Management of non point source pollution is mainly focused on land use and runoff management. As for the management and control of roof runoff, the green roof can be established; on the road runoff pollutants in the management and control measures are mainly controlled by the combination of engineering measures and non engineering measures. The engineering measures mainly include vegetation control, retention system, infiltration system, non-engineering measures are mainly road cleaning and policy management to control the sources of pollution. |
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