Ozonation of pyrene and benzo[a]pyrene in silica and soil - C-14-mass balances and chemical analysis of oxidation products as a first step to ecotoxicological evaluation

Ozonation of polycyclic aromatic hydrocarbons (PAHs) in soil is a process that can be used for in-situ soil remediation or in combination with bioremediation techniques. First steps to a comprehensive ecotoxicological evaluation of this method is done by ozonation of radioactively labeled (C-14) pyrene and benzo[a]pyrene in a silty soil (LUFA 2.2) under mass-balancing conditions and GCMS analysis of aromatic ozonation products. C-14-Mass-balances for pyrene and benzo[a]pyrene (b[a]p) in soil showed that, apart from (CO2)-C-14 formation, considerable percentages of both PAHs are oxidized to water soluble substances (20-30%) or to non-extractable or bound residues (10% for pyrene, 30% for b[a]p). TLC and GC-MS analysis of ozonation products extractable from artificially contaminated silica and soil by organic solvents revealed a large number of aromatic substances. PAH-quinones and ten ring fission products with formyl-and carboxy-groups of both pyrene and b[a]p could be identified.