Source Identification of Stranded Oils based on Stable Isotope Profiles of n-Alkanes after the Hebei Spirit Oil Spill Incident

Abstract

Oils from different sources have different chemical compositions and biomarker distributions, which can be used to identify the source of oil pollution. The chemical compositions of spilled oils, however, can be altered in the environment by a number of physicochemical and biological factors including evaporation, dissolution, photooxidation and microbial degradation, making source identification difficult. The stable isotope compositions of individual compounds in spilled oil remain relatively unaffected and therefore can be effectively used as a correlation parameter. After the Hebei Spirit oil spill incident, stranded oils collected in the West coast of Korea were analyzed by GC/IRMS (gas chromatograph / isotope ratio mass spectrometry) for stable isotope ratios of n-alkanes and compared with possible source oils, i.e., Iranian Heavy, KEC, and U/ZKUM. The stable isotope profiles of stranded oils showed similarity to those of Iranian Heavy crude oil and dissimilarity to those of KEC and U/ZKUM, clearly illustrating that Iranian Heavy crude oil was the major spilled oil among the three crude oils originally loaded in the tanker, Hebei Spirit. This study shows that stable isotope profile of n-alkanes can be effectively used to trace the source of oil spill.