The purpose of this study was to develop a fungal bioremediation method that could be used for soils
heavily contaminated with persistent organic compounds, such as polyaromatic hydrocarbons (PAHs).
Sawmill soil, contaminated with PAHs, was mixed with composted green waste (1:1) and incubated with
or without fungal inoculum. The treatments were performed at the laboratory and field scales. In the
laboratory scale treatment (starting concentration 3500 mg kg1, sum of 16 PAH) the high molecular
weight PAHs were degraded significantly more in the fungal-inoculated microcosms than in the uninoculated
ones. In the microcosms inoculated with Phanerochaete velutina, 96% of 4-ring PAHs and 39% of
5- and 6-ring PAHs were removed in three months. In the uninoculated microcosms, 55% of 4-ring PAHs
and only 7% of 5- and 6-ring PAHs were degraded. However, during the field scale (2 t) experiment at
lower starting concentration (1400 mg kg1, sum of 16 PAH) the % degradation was similar in both the
P. velutina-inoculated and the uninoculated treatments: 94% of the 16 PAHs were degraded in three
months. In the field scale experiment the copy number of gram-positive bacteria PAH-ring hydroxylating
dioxygenase genes was found to increase 1000 fold, indicating that bacterial PAH degradation also played
an important role.