Contamination, source identification, and risk assessment of polycyclic aromatic hydrocarbons in agricultural soils around a typical coking plant in Shandong, China

Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. Investigation of the contamination, distribution, and sources of PAHs in agricultural soils around Rong Xin coking plant, China, was conducted, and the potential human health risks were addressed. The total concentration of the 16 PAHs (Sigma(16)PAHs) on the United States Environmental Protection Agency priority list had a range from 1774 to 4621 mu g/kg (mean 3016 mu g/kg). Meanwhile, seven carcinogenic PAHs (Sigma PAH(7c)) owned the total concentrations of 684-2105 mu g/kg, and they had the benzo[a]pyrene equivalent (BaPeq) concentrations at 139.616-1672.850 mu g/kg. All soil samples were dominated by PAHs with two to four rings. Data analyses for the potential sources of PAHs showed that the PAHs in soils were principally from pyrogenic sources. Ecological risk assessment of soil PAHs showed that the BaPeq concentrations of Sigma PAH(7c) accounted for 99% of the total Sigma(16)PAHs, being a major carcinogenic contributors of Sigma(16)PAHs. Higher levels of PAHs and higher total BaPeq concentrations in this study indicate a potential carcinogenic risk for humans. Therefore, long-term exposure to coking plants may increase the PAH concentrations in the environment and further raise a potential risk to human health.