Degradation of Selected PAHs in Soil/Compost and Identification of Intermediates

Abstract

Solvent-extractable degradation products of polycyclic aromatic hydrocarbons formed in a soil/compost mixture were analysed using a clean-up procedure including solid phase extraction. From glass columns, containing silica gel deactivated with 6% water, two fractions were eluted: a moderately polar fraction of ketones and quinones and a more polar fraction of phenolic compounds and organic acids. Such oxidation products were identified using reversed-phase high performance liquid chromatography and gas chromatography-mass spectrometrv. Applying this method to a degradation study on four selected PAHs in soil/compost mixtures. 1-hydroxy-2-naphthoic acid could be found in the system fortified with phenanthrene. and 9-fluorenol and 9-fluorenone were identified as degradation products of fluorone. The occurrence of the latter in sterilized controls show, that PAH metabolism is accompanied by abiotic degradation mechanisms.

Key Words:

• Polycyclic aromatic hydrocarbons
• oxidation products
• soil/compost mixture
• analytical method
• HPLC
• GC-MS