Polycyclic aromatic hydrocarbons in soil around coal-fired power plants in Shandong, China

Abstract

This study comprehensively investigated the concentrations, distribution patterns, sources, and health risks of 16 polycyclic aromatic hydrocarbons (PAHs) found in soils around two thermal power plants in Shandong, China. The total concentrations of the 16 total PAHs (Σ16PAH) in the Longguang (LG) and Xinyuan (XY) thermal power plants were 1,031.78-2,744.06 and 1,383.8-2,924.8 μg/kg, respectively, with mean values of 1,925.2 and 2,303.1 μg/kg, respectively. Seven carcinogenic PAHs accounted for 45.5% and 55.7% of Σ16PAHs in soils around LG and XY thermal power plants, respectively. A similar composition pattern of PAHs was observed in soils around the two power plants. The contributions of four-ring PAHs, namely, fluoranthene (FLA), pyrene (PYR), benz[a]anthracene (BaA), and chrysene (CHR), were high; thus, the four-ring PAHs dominated in soils around the two power plants. With the increase of distance, most individual PAH concentrations decreased, and ∑16PAHs concentrations decreased significantly from 200 m to 500 m. However, the contributions of two-to three-ring PAHs increased with distance, whereas the contributions of four-ring PAHs decreased. Four PAH sources in soils around the two thermal power plants were identified by positive matrix factorization. Coal combustion was the main source of soil PAHs. Health-risk assessment based on toxic equivalency factors of benzo[a]pyrene indicated no risk of PAH contamination in soils around LG power plant and a low risk in those around XY power plant. This study highlights the distribution and sources of PAHs in soil around thermal power plants.