Polycyclic aromatic hydrocarbons (PAHs) in soils from a multi-industrial city, South Korea

We collected soil samples at 25 sites in Ulsan, Korea to investigate the levels, patterns, spatial distribution, and sources of polycyclic aromatic hydrocarbons (PAHs) in the summer 2010. The target compounds were the 16 US-EPA priority PAHs. For the source identification of PAHs, diagnostic ratios and the positive matrix factorization (PMF) model were used. The total concentrations of PAHs ranged from 65 ng/g to 12,000 ng/g (mean: 960 ng/g, median 330 ng/g). The levels and distribution of PAHs indicated that industrial areas were more polluted than rural and urban areas. The diagnostic ratios suggested that the soil samples were contaminated by pyrogenic sources and traffic emission. According to the result of PMF, four factors were identified: gasoline and heavy oil combustion (14%), diesel combustion (54%), coke oven (23%), and coal/biomass burning (9%). Therefore, it was concluded that vehicles and industrial complexes were major sources of PAHs in Ulsan.