Comparison?Source Apportionment And Ecological Risk Assessment Of PAHs Pollution Of Runoff From Roads In Suburb And Urban Areas Of Shanghai

With the rapid development of society and the acceleration of urbanization process,the environmental problems caused by urban runoff pollution are becoming more and more serious.Especially in the fast-growing cities in recent years,the expansion of traffic roads also brings a series of road runoff pollution problems.Among them,polycyclic aromatic hydrocarbons(PAHs)are common persistent organic pollutants(POPs)in road runoff.They exist widely in the environment and have attracted the attention of researchers because of their carcinogenic,teratogenic and mutagenic"three-lethal effects".Urban runoff is an important way for PAHs to enter surface water,and urban road runoff pollutes most seriously in urban runoff,and road runoff also has potential hazards to soil along the traffic line.Therefore,taking 16 PAHs under the priority control of the US Environmental Protection Agency(USEPA)as the research object,eight rainfall runoff samples were collected from Caobao Road in Shanghai and Jiajin Expressway in suburbs.The pollution characteristics,influencing factors,source analysis and ecological risk of PAHs in road runoff were analyzed and compared.The conclusions are as follows:(1)The mass concentration of ?16PAHs in Jiajin Expressway runoff is much higher than Caobao Road,and the geometric mean value of 16PAHs in Jiajin Expressway is 20.8 times higher than Caobao Road;Generally speaking,the EMC and load of Jiajin Expressway are higher than Caobao Road;the PAHs in road runoff are mainly particle phase,and the high ring proportion is higher;according to the national sewage discharge standard,both sampling points exceed the standard,especially Jiajin.The runoff dynamic characteristics of Caobao Road and Jiajin Highway are different,mainly affected by the peak rainfall.(2)PAHs pollution of road runoff is affected by rainfall and traffic factors,especially traffic factors.(3)Through the source analysis of PAHs by characteristic ratio method and PMF model,it is found that there are three main sources of PAHs in Caobao route flow,namely gas/coal source(48.6%),traffic emission source(29.8%)and petroleum source(21.7%).There are four main sources of PAHs in Jiajin high-speed runoff,namely,traffic emission source(3 8.5%),coal source(34.6%),petroleum source(14.6%)and coking source(12.6%).(4)The ecological risk assessment of ?16PAHs by risk entropy method shows that the middle ecological risk of Caobao Road PAHs is higher than that of Jiajin Highway PAHs.From 16PAHs,the two sampling points are in high ecological risk level,and the ecological risk of PAHs of all rainfall runoff sites in Jiajin Highway is higher than that of Caobao Road.