Spatial And Temporal Distribution And Source Apportionment Of PAHs From Foliar Particles In Nanjing

Polycyclic aromatic hydrocarbons(PAHs) are widespread in the environment of a class of persistent organic pollutants(POPs), mainly produced by incomplete combustion of coal, oil and other fossil fuels, majority adsorbed on a particle size of less than 10?m particles. Due to bioaccumulation, semi-volatile and significant "three-induced" effect(carcinogenic, teratogenic and mutagenic effects), the 16 PAHs in 1976 was included in the US EPA priority pollutant list, has attracted extensive attention of domestic and foreign researchers. The city is an important human activity, and urban green plants is an important part of the urban ecosystem, due to a special plant leaf surface structure can retain and fix atmospheric particulate pollutants, plant become an important filter body for reducing urban air pollution.In this study, the contents of 15 priority PAHs were quantitiative detected in the foliar particles of Nanjing green plants by high-performance liquid chromatography(HPLC), studying on the distribution characteristics of PAHs in different seasons and different functional areas, and analyzing its source and evaluating ecological risk of PAHs in foliar particles, the following conclusions:(1) Foliar particles samples from different seasons and different functional areas of Nanjing were detected to contain PAHs. ?15PAHs of the foliar particles showed winter> autumn> spring> summer, the mass fraction of PAHs in different seasons of traffic were 1182.57~2103.93?g/kg(mean value: 1636.05?g/kg); ?15PAHs of the foliar particles showed traffic> chemical zone> cultural and educational area> residential?scenic, the mass fraction of PAHs in different functional areas in winter were733.19~2103.93?g/kg(mean value: 1313.60?g/kg).Foliar particles in spring and winter are 4-ring,5-ring and 6-ring in the main, summer and autumn 3-ring,4-ring and 5-ring in the main. Foliar particles of different functional areas are based on 4-ring and 5-ring.The concentrations of Pyr, Bb F,Chry were highest in different seasons, the levels of Nap,Flu,An were lowest in all samples. The concentrations of Phe, Pyr, BbF,Chry were highest in different functional areas. Various functional areas of plant foliar particles composition have a consistency, showed foliar particles pollution sources of PAHs in different functional areas are similar or identical.(2) With a different number of rings PAHs relative abundance method and ratio characteristics method in urban plant foliar particles to study the source apportionment, pollution comes mainly from vehicle exhaust and incomplete combustion of fossil fuels.(3) Single factor index and Nemerow comprehensive index evaluation showed that the foliar particles of traffic and chemical zone has been seriously contaminated PAHs, and other functional areas were also subject to some degree of PAHs pollution, although pollution is not serious, but still can not be ignored. In addition, the various functional areas of TEQBaP varying degrees of overweight, especially in traffic areas and chemical area has been seriously overweight, because urban transport more vehicles, vehicle exhaust pollution, chemical zone industrial production process more coal-fired combustion emissions, have high ecological risk, attention should be paid.