TREATMENT OF A PENTACHLOROPHENOL-CONTAMINATED AND CREOSOTE-CONTAMINATED SOIL USING THE LIGNIN-DEGRADING FUNGUS PHANEROCHAETE-SORDIDA - A FIELD DEMONSTRATION

The feasibility of large-scale fungal bioaugmentation was evaluated by assessing the ability of the lignin-degrading fungus Phanerochaete sordida to decrease the soil concentrations of pentachlorophenol (PCP) and 13 priority pollutant polynuclear aromatic (PNA) creosote components in a field-demonstration study. Inoculation of the contaminated soil with the fungus (fungal treatment) at a rate of 10% (dry wt fungal hyphae and inoculum substrate dry wt soil(-1)) was compared to amending the soil (amended control) with sterile inoculum substrate also at a 10% rate (dry wt substrate dry wt soil(-1)) and no treatment (non-amended control), for their effects on PCP and PNA concentrations over 20 wk. The initial soil PCP and total measured PNA concentrations for the three treatments averaged 1058 and 1210 mg kg(-1), respectively. Despite very low initial amounts of fungal biomass, determined from ergosterol concentrations in the inoculum and inoculated soil, there was a 64% PCP decrease to a residual concentration of 362 mg kg(-1) in the fungal-treated soil after 20 wk of treatment. This residual concentration was statistically less than the 715 mg kg(-1) (26% decrease) and the 985 mg kg(-1) (18% decrease) PCP concentrations observed in the amended control and the non-amended control soils, respectively. There were significant decreases in the concentrations of 3- and 4-ring PNAs in all treatments. With the exception of acenapthene, decreases in the concentrations of 3-ring PNAs were significantly greater in the non-amended control soil than in either the amended control or fungal-treated soils. Conversely, decreases in the concentration of 4-ring PNAs tended to be greater in the fungal-treated and amended control soils than in the non-amended control soils. The concentrations of 5- and 6-ring PNAs were not decreased significantly by any of the treatments.