SINOPSIS

Spent mushroom substrate represents an environmental problem owing to its bulk volume as a waste material. Reclamation of contaminated soils is one potential use of spent mushroom substrate. The present study describes the capacity of spent substrate from commercial oyster mushroom (Pleurotus ostreatus) production to remove polycyclic aromatic hydrocarbons from weathered creosote in a highly contaminated (PAH sum 6473 mg/kg) soil of a former abandoned wood preservation site. Addition of the spent fungal compost resulted in a reduction of 3-ring compounds, from 50% (acenaphthene, anthracene) to 87% (phenanthrene, fluorene) after a 12-week treatment period. The reduction increased to 87% (anthracene) and 97−99% (fluorene, phenanthrene, acenaphthene) after additional reinoculation with spent fungal substrate and another 3-week incubation period. The effect on 4-ring compounds was much less pronounced, and reduction was measured only for fluoranthene and pyrene, with 43% and 34% decrease, respectively, after 12 weeks of the fungal treatment. Again, reinoculation had a positive effect and increased reduction to 59% and 51%, respectively. These results demonstrate the PAH-removal capacity of spent oyster mushroom substrate in highly contaminated soil.