Iranian Journal of

Background and Objectives: Few investigations on polycyclic aromatic hydrocarbons (PAHs) in surface sediments have reported medium to high petrogenic contamination at the southwest coasts of the Caspian Sea. The aim of this study was to investigate distribution and potential sources of 16 PAH compounds in surface sediments of the southwest coasts of the Caspian Sea (Gillan province). Materials and methods: A total of 45 sediment samples from 15 stations at coasts of the Gillan province (from Astara to Lahijan) were collected from 10, 20, and 50 meters depths. Each sample was analyzed using Gas chromatography – Mass spectrometry. Diagnostic ratios were used for source identification. Results: The main PAH compounds in the study area were phenanthrene (87.6±74.6 ng/g), pyrene (43.1±23.5 ng/g), and naphthalene (34.4±40.4 ng/g) respectively. According to the calculated diagnostic ratios such as LMW/HMW (0.25-7.75), Ant/178 (0.02-0.11), Flu/202 (0.20-0.49), and B(a)Ant/228 (0.09-0.54) the main source of PAHs is petrogenic in this study area. Conclusion: According to PAH diagnostic ratios and similarity of dominant PAH compounds in study area with dominant PAH compounds of Azerbaijan oil field, main probable source of PAH compounds in Gillan province coasts is Azerbaijan oil pollution.