Distribution of Polycyclic Aromatic Hydrocarbons in Coal Gangue and Emitted Gas with Low-Temperature Spontaneous Combustion in Situ

摘要

Five coal gangue samples from the Duerping Coal Mine in Shanxi, China, subjected to low-temperature combustion and their emitted gas samples were collected in situ at the combustion temperatures of 23, 33, 49, 57, and 70 degrees C. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in these samples were determined by high-performance liquid chromatography; these concentrations indicated that with decreasing combustion temperature, Sigma(16)PAHs in coal gangue tend to decrease, whereas Sigma(16)PAHs in emitted gas tend to increase. With the decrease of combustion temperature, the concentrations of Sigma(6)LPAHs in coal gangue and emitted gas decreased, whereas the concentrations of Sigma(10)HPAHs increased; therefore, the overall toxicity and carcinogenicity increased. The total index of PAHs in the samples ranged from 20.10 to 22.43 with a mean of 21.81. The ratio of Flua/(Flua + Pyr) ranged from 0.34 to 0.97 with a mean of 0.76. Finally, the proportions of Ant/(Ant + Phe), BaA/(BaA + Chr), and InP/(InP + Bghi) were approximately 1. These ratios and the total index of the PAHs could be used to identify the source of PAHs in the atmosphere and soil.