Source analysis for polycyclic aromatic hydrocarbon in road dust and urban runoff using marker compounds

Automobile traffic, although extremely important to human society has imparted a growing environmental impact through automobile emissions. For that reason, some studies have investigated origin specification methods for polycyclic aromatic hydrocarbons (PAHs) in road dust and sediments. Typically, PAHs biodegrade and photodegrade easily in environmental conditions. As marker compounds to specify their origin, biologically and photochemically stable compounds are desirable. In this study, we attempt to examine whether tri-terpanes are useful for origin specification of PAH pollution in road dust using an estimation method to determine the pollution source of PAH. This method might clarify pollution sources that cannot be clarified using conventional methods based on the PAH profiles. These results shown that the most important source of PAH in road dust seems to be tires while road pavement asphalt was a second pollution source. Furthermore, results clarified that the source of PAHs in runoff water is road dust.

An estimation method to determine the pollution source of PAHs in road dust based on the profiles of tri-terpanes was used in this study. Table 1 Total concentration of PAHs and tri-terpanes in road dust and pollution source samples Tire Total PAHs (ng/g) Total tri-terpanes (ng/g) Number of samples PAHs/tri-terpanes (−) Road pavement asphalt Fuel oil Lubricant oil Exhaust particle phase Road dust 93,139 10.1 2.5 2.2 1.5 3.7 45,809 21,831 2.1 This method can clarify pollution sources that cannot be clarified using conventional methods based on the PAH profiles. Simultaneously, this study specified the main sources of PAHs in road dust in Okayama city using this technique. Results revealed that the most important source of PAHs in road dust in Okayama city is automobile tires; asphalt for road pavement was the next greatest pollution source. Results also clarified that the source of PAHs in runoff water was road dust.