Polycyclic aromatic hydrocarbons were extracted from a soil sample using ultrasound and dichloromethane-, cyclohexane-, and toluene-water mixtures. It was found that when dichloromethane is used as an extractant, acenaphthylene reacts with the solvent. Several chlorinated and oxygenated derivatives were identified. The results show that chlorinated solvents should be avoided because of their sonolytic decomposition. Particularly unsaturated nonaromatic compounds might react with intermediate decomposition radicals of the solvent.