Soils contaminated with PAH: a long term natural attenuation assessment
Résumé
Currently the demonstration of the presence of sites contaminated by organic compounds, and the importance of decontamination needs no introduction. Indeed, human activity is generating more and more contaminated soils and polycyclic aromatic hydrocarbons (PAH) are amongst the contaminants most frequently encountered. Although natural attenuation is often depreciated by people because associated with inaction of contaminated land owners, it might represent a valuable alternative to classical treatments such as physico-chemical treatments. Indeed, this technic aims at reducing the concentration of pollutants while minimizing human intervention and therefore costs. A misunderstanding of this method and a small amount of data available does not encourage its development in France. This present work proposes the results obtained during a long-term natural attenuation assessment in real climatic conditions. This study was performed on seventy-two off ground plots filled with contaminated soils from different former industrial sites (coking industry, manufactured gas plants) whose initial concentration of PAH varies between 380 and 2077 mg/kg. The impact diagnosis was made on this device after ten years under natural attenuation. This diagnosis included leached water analysis, soil PAHs concentrations, as well as evaluation of vegetation cover quality and quantity.