Soils impacted by PAHs: Would the stabilized organic matter be a green tool for the immobilization of these noxious compounds?

The objective of this study was to investigate the role of stabilized organic matter (vermicompost) and tropical soils in the sorption of naphthalene, anthracene and benzo[a]pyrene. The results obtained for the three compounds were extrapolated for the priority polycyclic aromatic hydrocarbons (PAHs) pollutants according to Environmental Protection Agency (US EPA). To evaluate the sorption process, high performance liquid chromatography was employed and the data was fitted by Freundlich isotherms. The results suggest that the sorption effect generally increases with the number of benzene rings of the PAHs, and that the persistence of PAHs in the environment is possibly related to the number of benzene rings in the PAH molecule. In addition, the pH of the vermicompost can strongly affect the adsorption process in this matrix.