PAHs in road dust of Nanjing Chemical Industry Park, China: chemical composition, sources, and risk assessment.

The objectives of the present study were to research the chemical composition of PAHs in PM2.5 of road dust, explore potential sources of PAHs, and assess their carcinogenic risk. Fifty-six road dust samples were collected on the arterial and sub-arterial roads at Nanjing Chemical Industry Park during the sampling periods of autumn and winter. A resuspension system in the laboratory was used to simulate the naturally suspended road dust in the environment and collect PM2.5. Ace was not detected, but other PAHs were found. The pollution level of PAHs was 43.66 ± 15.79 mg kg-1; and 4-ring PAHs, which accounted for 35.14% of PAHs, were the main pollutants. The contents of BeP and BghiP were the highest, accounting for 12.23% and 12.06% of PAHs, respectively. The PAHs concentrations were found to be higher in winter due to the physicochemical characteristics of PAHs and the meteorological conditions. The sequence of PAHs concentrations was: sub-arterial road in winter > arterial road in winter > arterial road in autumn > sub-arterial road in autumn. Traffic emission and industrial sources led to higher PAHs concentrations on the arterial roads in autumn. Meteorological conditions and road characteristics, such as vehicular speed, frequency of road dust sweeping, and road width, led to higher PAHs concentrations on the sub-arterial roads in winter. Principal component analysis (PCA) and the ratios of Ant/(Ant + Phe), Flu/(Flu + Pyr), InP/(InP + BP), and BaA/(BaA + Chr) were used to distinguish the PAHs sources, which indicated fossil fuel combustion, traffic emissions, and petroleum exhaust as the main PAHs sources. The application of the ILCR model for PAHs in road dust showed a higher carcinogenic risk for children and adults (6.01 × 10-5 and 5.80 × 10-5, respectively) on the sub-arterial roads in winter, indicating a high potential carcinogenic risk at the Chemical Industrial Park.