Survey of the residual polycyclic aromatic hydrocarbons in petroleum contaminated soils in Shahrekord in 2013

Polycyclic aromatic hydrocarbons (PAHs) are one of the widespread and contaminant throughout the nature, due to toxicity, carcinogenicity, their relative resistance to biodegradation. The main origin that introduced this contamination to environment is oil and oil products. This study aimed to determine the residual polycyclic aromatic hydrocarbons (PAHs) in petroleum contaminated soils in Shahrekord. In this descriptive–analytical study, random samples were taken from three contaminated sites, including; vicinity transmission line site after accident pipeline break, exposed to exhaust site and oil storage reservoirs site. Phenanthrene and pyrene extraction was carried out and then their concentrations were measured using HPLC/UV. The SPSS software was used for analysis (t- test and Spearman’s rho test). The results showed that the average of phenanthrene and pyrene in vicinity crude oil transmission line site were 24.14±6.8 and 50.67±20.42 mg/kg, respectively. These amounts were measured in storage reservoirs site 0.22±0.02 and 2.5±1 mg/kg and in areas exposed to exhaust 32.24±19.45 and 61.32±36.23, respectively. The relationship between phenanthrene and pyrene concentrations both in vicinity crude oil transmission line site and oil reservoirs site according to WHO and ATSDR standards and in gas station site according to WHO standard were significant (P<0.05); that indicating high contamination at these sites. Mean concentrations of phenanthrene and pyrene in vicinity crude oil transmission line site were 200 to 500 times and in areas exposed to exhaust were 6 to 12 times more than WHO standards. Thus, appropriate soil remediation (especially bioremediation) approaches should be considered.