PAH-DEGRADING MICROORGANISMS POTENTIALLY USEFUL FOR BIOREMEDIATION DETECTED IN CONTAMINATED SOIL AT A TAR REFINERY

Site characterization and biofeasibility testing have been done on contaminated soil in an Iranian tar refinery located near Isfahan. For many years before the refinery was built, the coal tar from the coke production process at the nearby Isfahan Iron Foundry Unit was stored in unsealed lagoons, and this has led to severe and extensive soil pollution and a threat to the Zayandehrood River. Soil samples were taken from six locations around the site, and subjected to a standard assay for the presence of microorganisms capable of degrading polycyclic aromatic hydrocarbons (PAHs). In several samples fungi were found that degraded naphthalene, anthracene, and phenanthrene, the three PAHs used in the tests. Moreover, when grown in a pure culture with organic nutrients at 25-30 °C, these fungi reduced these PAHs from their water solubility concentrations to undetectability. We plan further studies to gain knowledge of these microorganisms, so that they can be applied to bioremediation of this site and others contaminated by PAHs.