Investigating Oil Entrance from Hendijan Oil Field in the Northwest of the Persian Gulf Using Chemical Fingerprinting

Concerning the entrance of oil into the Persian Gulf due to the presence of oil fields in this ecosystem, a wide investigation was carried out in 2017 to evaluate the hydrocarbons source identification and chemical fingerprinting. To this end, surface sediments were collected from the Persian Gulf. In the laboratory, compounds (n-alkanes, PAHs, hopane and sterane) were then extracted with a Soxhlet system and two steps of chromatographic columns and analyzed using a GC–MS instrument. The results showed that the concentrations of the n-alkanes and Σ30 PAHs increased with a reduction in distance from hot spots. This suggests that high concentrations of hydrocarbons in the locations near the hot spots might be due to oil leakage, transportation of and exploration for oil, pipeline fractures and industrial activities. A positive relation between total organic matter (TOM) and hydrocarbons was observed. A common petrogenic hydrocarbon source was strongly implied in most places by the presence of unresolved compounds resolved (UCM), lower molecular weight/higher molecular weight (LMW/HMW) and carbon preference index (CPI) ratios < 1. Typical profiles of petrogenic PAHs with predominant alkyl substituted naphthalene and phenanthrene, various PAH ratios and multivariate analysis showed that PAHs were mainly derived from petrogenic sources. Simultaneous use of n-alkanes and PAHs in source identification can be effective to precisely specify the hydrocarbon sources in complicated mixture ecosystems. Furthermore, using multivariate analysis and chemical fingerprinting of n-alkanes, PAHs, hopanes and sterane confirmed that Hendijan crude oil may be the source of the sediment pollution in the study area.

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