LABILE POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) IN FLY ASH RECLAIMED TECHNOSOLS

Total contents of labile solvent extractable polycyclic aromatic hydrocarbons (PAHs) were analysed in Technosols containing yellow-greenish clays intermixed with black clays and amended with fly ash in the 1970s around the area of the largest coal-producing complex in Eastern Europe. The sum of PAHs due to the high acenaphthylene content exceeds the maximum permissible levels of the national legislation of Bulgaria and the EU regulations. The fraction of low-molecular DAIs exceeds the high-molecular homologues (> 3 rings), showing that the majority of PAHs result from low to medium-temperature coal combustion. Principal component analysis was conducted to reveal sources of PAHs. Labile PAHs were not related to the total organic carbon (TOC) or water drop penetration time (WDPT) in the Technosols, except for benzo(g,h,i)perylene which correlated with TOC. Source identification on calculating the isomeric ratios of PAHs confirms that most PAHs originate from coal combustion, pointing at the ash as the main source.