Distributions of polycyclic aromatic hydrocarbons in coal in China1665-1674

Abstract

Groundwater level rises rapidly when mine drainage systems stop functioning after mine closures. Free-form polycyclic aromatic hydrocarbons (PAHs) in residual pillaring and abandoned mining levels could continue to migrate because of eluviation leaching. Moreover, other aquifers are polluted with mine water through mining-induced fractures, faults, and poorly sealed drill holes. Therefore, the distributions of 16-PAHs in raw coal mined in China and the factors influencing these distributions were analyzed to assist mine closures. The results showed that the average concentration of PAHs was 10.540±7.973 µg/g in the raw coal samples, and PAHs with low molecular weights had the highest abundances, accounting for 44% of the total PAH concentration obtained. The highest concentration of 16-PAHs was observed in bituminous coals, followed by that in lignite, and the lowest is anthracite. The influence factors analysis reveals that carbon content, volatile matter, H/C, and O/C have a significant effect on PAH content in raw coals. The volatile matter and molar ratio of H/C play a leading role in the changing process in 16 PAHs, accounting for more than 60% of the total contribution.