Occurrence, sources, and potential human health risks of polycyclic aromatic hydrocarbons in agricultural soils of the coal production area surrounding Xinzhou, China

A comprehensive investigation of the levels, distribution patterns, and sources of polycyclic aromatic hydrocarbons (PAHs) in agricultural soils of the coal production area surrounding Xinzhou, China, was conducted, and the potential human health risks associated with the levels observed were addressed. A total of 247 samples collected from agricultural soils from the area were analyzed for sixteen PAHs, including highly carcinogenic isomers. The PAH concentrations had a range of n.d. to 782 ng g(-1), with a mean value of 202 ng g(-1). The two-three ring PAHs were the dominant species, making up 60 percent of total PAHs. Compared with the pollution levels and carcinogenic potential risks reported in other studies, the soil PAH concentrations in the study area were in the low to intermediate range. A positive matrix factorization model indicates that coal/biomass combustion, coal and oil combustion, and coke ovens are the primary PAH sources, accounting for 33 percent, 26 percent, and 24 percent of total PAHs, respectively. The benzo[a]pyrene equivalent (BaPeq) concentrations had a range of n.d. to 476 ng g(-1) for PAH(7c), with a mean value of 34 ng g(-1). The BaPeq concentrations of PAH(7c) accounted for more than 99 percent of the Sigma PAH(16), which suggests that seven PAHs were major carcinogenic contributors of Sigma PAH(16). According to the Canadian Soil Quality Guidelines, only six of the soil samples had concentrations above the safe BaPeq value of 600 ng g(-1); the elevated concentrations observed at these sites can be attributed to coal combustion and industrial activities. Exposure to these soils through direct contact probably poses a significant risk to human health as a result of the carcinogenic effects of PAHs. (C) 2014 Elsevier Inc. All rights reserved.