Bioremediation of Soil Contaminated with Explosives at the Naval Weapons Station Yorktown

The explosives TNT, HMX, and RDX are integral components of many munitions. The wastes from the manufacture and the use of these and other explosives has resulted in substantial contamination of water and soil. White rot fungi have been proposed for use in the bioremediation of contaminated soil and water. Strains of Phanerochaete chrysosporium and Pleurotus ostreatus adapted to grow on high concentrations of TNT were studied with regard to their ability to degrade TNT in liquid cultures. Both strains were able to cause extensive degradation of TNT. Field bioremediation studies using P. ostreatus were performed on site at the Yorktown Naval Weapons Station Yorktown (Yorktown, VA). In two plots, 6 cubic yards of soil contaminated with TNT, HMX, and RDX were blended with 3 cubic yards of a substrate mixture containing nutrients that promote the growth of fungi. In soil amended with growth substrate and P. ostreatus, concentrations of TNT, HMX and RDX were reduced from 194.0±50, 61±20 mg/kg and 118.0±30 to 3±4, 18±7 and 5±3 mg/kg, respectively, during a 62-day incubation period. Interestingly, in soil that was amended with this substrate mixture, but not with P. ostreatus, the concentrations of TNT, HMX, and RDX were also reduced substantially from 283±100, 67±20, and 144±50 mg/kg to 10±10, 34±20, and 12±10 mg/kg, respectively, during the same period. Thus, it appears that addition of amendments that enhance the growth and activity of indigenous microorganisms was sufficient to promote extensive degradation of these compounds in soil.