Bioremediation of Polycyclic Aromatic Hydrocarbons contaminated soil by some fungal species

Polycyclic aromatic hydrocarbons (PAHs) are counted as important pollutants due to their ubiquitous occurrence and toxicity, mutagenic and carcinogenicity characteristics. They are counted as the main pollutants of soil. One of the most effective, environmentally friendly and cost-effective methods is bioremediation of contaminated soils. Fungi have been identified as the most successful microorganisms in the removal of these compounds. The purpose of this study was to identify endemic fungal strains compatible with PAH compounds. Contaminated dumping site of acidic sludge, produced from the recycling process of used oils in Eshtehard industrial complex was selected as the study area. Some endemic fungal species including Aspergillus fumigatus, Alternaria chlamydosporigena and Penicillium chrysogenum were isolated from contaminated soil and inoculated into contaminated soil. To examine the efficiency of fungal remediation of PAHs, after 21 and 50 days of inoculation, residual PAHs concentrations were measured by Gas chromatography mass spectrometry (GC/MS). The results interpreted by the mean and standard deviation of data using Excel software and comparison of means by Tukey HSD test. The results revealed that all three fungal species, identified in this study, were significantly effective in eliminating PAHs. The highest removal rate related to Naphthalene and Acenaphthene was due to the volatility of these compounds. Removal of Benzo [a] pyrene, which is the most cancerous PAH and has the highest molecular weight in this study, was 50%, 40% and 32% by Aspergillus fumigatus, Alternaria chlamydosporigena and Penicillium chrysogenum isolates, respectively. In addition, there was a significant difference between different species in reducing the concentration of different PAHs, at α = .05.