COMPARISON OF SOXHLET AND SHAKE EXTRACTION OF POLYCYCLIC AROMATIC-HYDROCARBONS FROM COAL-TAR POLLUTED SOILS SAMPLED IN THE FIELD

This study compares three extraction methods for PAHs in coal tar polluted soil: 3-times repeated shaking of the soil with dichloromethane-methanol (1:1), Soxhlet extraction with dichloromethane, and Soxhlet extraction with dichloromethane followed by Soxhlet extraction with methanol. The extraction efficiencies were determined for ten selected PAHs in triplicate samples of six soils sampled at former gasworks sites. The samples covered a wide range of PAH concentrations, from 0.6 to 397 mg/kg soil. Soxhlet extraction with dichloromethane followed by Soxhlet extraction with methanol, in general, was the most efficient method yielding 30 to 50 % higher concentrations than the other methods.