[Characterization of PAHs in fly ashes from coke production]

In order to investigate the characteristics of polycyclic aromatic hydrocarbons (PAHs) in ashes from coking, PAHs in ashes from three coke production plants were analyzed with GC-MS, and the distribution characteristics of PAHs and potential toxicity risk were discussed. The sum of 16 EPA prior PAHs varied from 8.17 x 10(2) to 5.17 x 10(3) microg x g(-1). PAH contents from the coke oven (stamp charging) with the height of 3.2 m were two times higher than those from the one (top charging) with the height of 6.0 m, and PAHs in ashes from coal charging were significantly higher than those from coke pushing in the same plant. Four-ring and five-ring PAHs were the dominant species in ashes from coking and the sum of them accounted for more than 80.00% of total PAHs. Chrysene (Chr), benzo [a] anthracene (BaA) and benzo [b] fluoranthene (BbF) were abundant in all ash samples. The content of total BaP-based toxic equivalency (BaPeq) ranged from 1.64 x 10(2) to 9.57 x 10(2) microg x g(-1). From the carcinogenic point of view, besides benzo [a] pyrene (BaP), dibenz [a,h] anthracene (DbA) contributed most to the overall toxicity of PAHs, followed by BaA and BbF. BaPeq concentration from coal charging was 5.21-fold higher than that from coke pushing, indicating that different reuse ways should be considered based on their specific toxicity profiles of PAHs.