Determination of polycyclic aromatic hydrocarbon (PAH) leaching from contaminated soil by a column test with on-line solid phase extraction

An on-line solid phase extraction was incorporated into a column leaching test for the investigation of hydrophobic organic contaminants leaching from soil. Chromatographic effects during leaching were minimized by using a short soil column (3 cm). A total of 10–20 ng of polycyclic aromatic hydrocarbons (PAHs) sorbed onto the device during the experiments, which was negligible for the PAH balance. Using 2 liters of 50 mM calcium chloride solution 0.06 to 0.2 % of the PAH amount from 300 g of sewage farm soils was leached within 40 hours, pointing at the limited availability of these contaminants. Contrary to the soils investigated, their leachates were dominated by low molecular weight three-ring PAHs (acenaphthylene to phenanthrene). The leachability of the individual PAHs was clearly related to their molecular weight and hydrophobicity with desorption percentages ranging from 1–10% for acenaphthene to below 0.02 % for pyrene and higher PAHs.