Effect of salinity on biodegradation of polycyclic aromatic hydrocarbons (PAHs) of heavy crude oil in soil.

The spillage of crude oil in the soil damages the environment. Polycyclic aromatic hydrocarbons (PAHs) are one of the crude oil components that may be harmful for living organisms. PAHs can disappear from the environment by volatilization and biodegradation. The effect of different NaCl concentrations (0%-5%) on PAHs reduction from the heavy crude oil-contaminated soil was studied. Our results showed that increasing NaCl concentration in soil had decreasing effect on total crude oil and PAHs reduction. The biodegradation of total crude oil was higher in 0% NaCl (41%) while higher total PAHs reduction was observed in 1% NaCl (35%). The lower total crude oil and PAHs reduction were observed in 5% NaCl (12% and 8% respectively). Phenanthrene, anthracene and pyrene reduction were higher in 1% NaCl, while fluoranthene and chrysene reduction were higher in 0% NaCl.