Are physico-chemical soil characteristics key factors to select the polycyclic aromatic hydrocarbons extraction procedure?

摘要

The aim of this work was to assess the impact of soil characteristics and constituents in the total extraction of hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAH), in real polluted soil samples from different sources. Soil samples were obtained from a wood creosote treatment plant, in the vicinity of a metallurgy industry and coal thermal power stations. Soils showed a wide diversity of textures, organic matter (OM) and CaCO3 content, pH and electrical conductivity to assure representativeness of multiple situations. Two extraction procedures with soft (solid-liquid extraction, SLE) and intense (pressurised liquid extraction, PLE) extraction power were used to determine the total concentration of PAH in soils. Results obtained showed that soil properties affect the effectiveness of the extraction procedures tested. The validation of PAH extraction procedure with a reference soil did not confirm that the procedure was adequate for all kinds of soil. Results showed that OM content and clay were the main soil characteristics that should be taken into account to select the most adequate PAH extraction procedure for any given polluted soil.