Soil piles and windrows are created by mixing soil with wood chips, corn cobs, or other ligno-cellulosic materials and adding fungal inoculum on a lignocellulosic base. The pile is then left for an extended period of time with regular turning and wetting for composting, or no turning for the static pile. This approach can lead to a rapid disappearance of explosive contaminants. A number of different fungal inoculants have been tried. For example, Jerger and Woodull (2000) used Trametes versicolour and P. chrysosporium as soil pile inoculants, Fritsche et al. (2000) used Stropharia rugosoannulata and Spreinart et al. (1998) used B. adusta. This approach is being widely used in the United States for the clean up of military sites (USAEC 1999). However, criticisms of this technique include the long incubation times needed for complete disappearance of the target substrate, and the high costs of set-up and maintenance. The process is further criticised for being based on unknown biological processes that may produce toxic breakdown products that bind to soil organic matter and undergo no further mineralization (Hawari 2000). Furthermore, in many cases it has been shown that added microbial inoculants did not persist in the environment and it was the indigenous micro flora that achieved much of the degradation (Gerth et al. 2001).
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