Polycyclic aromatic hydrocarbons in two sedimentary environments of the Tertiary Krepoljin coal basin

Abstract

In the present study, statistical correlation analysis and multivariate statistical techniques (PCA/FA) were employed to investigate polycyclic aromatic hydrocarbons (PAHs) in sediments, such as illite-montmorillonite (IM) and calcite (Ct), from two sedimentary environments of the Tertiary Krepoljin brown coal basin in Serbia. The coal and sediment layers were formed in fresh-water bogs during the Lower Miocene period. The total amount of extractable PAHs was determined by gas chromatography with a triple quad mass detector (GC-MS-MS), and it ranged from 449 to 10585 μg l−1 in all sediments. Eight of the total 16 PAHs, which ranged from 175.17 to 658.42 μg l−1, include benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene, which are regarded as potentially carcinogenic, indicating a higher possibility of adverse ecological effects. Medium molecular-weight (MMW) PAHs were found to be predominant in all sediments. PAH concentrations are affected by several factors, such as carbon content, H/C mole ratio, and (less significant) O/C mole ratio. The non-existence of a correlation between the N/C ratio and other parameters indicates unspecific changes which accompany the original organic matter. The lower-sulfur Ct sediment samples were found to have a higher PAH content than higher sulfur IM samples, leading to the conclusion that the PAH content of sediments may be related to the depositional environment.