Soil biological activities during the bioremediation of diesel contaminated soils

The responses of six agricultural soils, different in chemical, physical and biological characteristics. to diesel contamination were monitored during a 90-d incubation period. An evaluation of some enzyme activities and soil basal respiration as biological soil parameters to monitor Soil status and quality during the decontamination process from total petroleum hydrocarbons (TPH) was carried out. Three samples were used: S (control. uncontaminated soil), CS (contaminated soil), SCS (sterilized contaminated soil). The relationships between soil parameters and the levels of TPH residues were investigated. Results showed large loss of TPH. ranging between 28% and 40%. due to volatilization ill all treatments during the first 10-d incubation period. The most effective biodegradation ability was ill organic and coarse-textured soils. TPH strongly inhibited enzyme activities. mainly lipase and dehydrogenase. The soil respiration dynamics was reproduced satisfactorily by a kinetic model able to fit a flush of C mineralization followed by it stabilization phase. beta-glucosidase activity and basal respiration were the best biochemical parameters for monitoring soil status and quality during the bioremediation process.