Granulometry and surfactants, key factors in desorption and biodegradation (T.versicolor) of PAHs in soil and groundwater

Abstract

High hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) is the most limiting factor for the remediation of polluted soils and aquifers. The present study analyzes the effect of three nonionic surfactants (Tween 80, BS-400, and Gold Crew) and the granulometry of soil (1 %, 5 %, 10 %, and 20 % of clay and silt) on desorption of a PAH mixture (fluorene, phenanthrene, anthracene, and pyrene). As a general trend, decrease of fine material content and increase of surfactant concentration raises desorption. However, some particularities have to be considered depending on granulometry together with the surfactant applied. Furthermore, increase of fine material content tends to reduce the importance of the PAH properties, e.g., K ow and solubility, in desorption. To complete the remediation process, biodegradation by Trametes versicolor was tested with the surfactant Tween 80. Results indicate that a high concentration of surfactant does not affect the efficiency of fungus bioremediation. Nevertheless, high fine material content in soil/aquifer can reduce the degradation rate. Moreover, desorption and biodegradation used synergically guarantee better overall results in the remediation of soils polluted by PAH mixtures than other methods that separate desorption and remediation