The Variation Of Carbon Stable Isotopic Fingerprints Of Spill Oil In The Simulation Weathering Process

After the oil spill occurred, oil spill which is floating in the sea will be weathered, weathering can cause varying degrees of changes in the chemical composition of the oil, n-alkanes and polycyclic aromatic hydrocarbons distribution will change. Especially after long-term weathering, the detection means in GC-MS will be limited.In this paper, there are outdoor and indoor simulated weathering experiments in 380# fuel oil and crude oil in Kuwait. Conventional methods for identifying and checking the oil spill is in GC-MS technique, in addition, on the basis of the carbon isotope ratios of the oils had the inherited effect, using carbon stable isotopes can identify crude oil fingerprint. Hence there is a need to find stable and strong wind resistance stable carbon isotope ratios related diagnostics.Through the analysis showed that:n-alkanes stable carbon isotope values from the oil sample without any weathered original 380# fuel oil in a range of -24.21‰～-30.191‰, after experiencing long-term weathering stable carbon isotope values in a range of -25.849‰～-30.976‰. N-alkanes stable carbon isotope values from the original Kuwaiti crude oil remains within the range of -25.682‰～31.778‰, while short-term crude oil samples after weathering stable carbon isotope values of n-alkanes in the range of-24.759‰～30.875‰, after long-term weathering n-alkanes stable carbon isotope values in the range of Kuwaiti crude -26.718‰～-21.142‰.The short-term or long-term weathering simulation experiment for the n-alkanes indicators were performed on the 380# fuel oil and Kuwaiti crude oi in the laboratory, δ13CPr/C19,δ13CPh/C19,δ13CPr/C20 and 813CPh/C20, as diagnostic indexes, showing a certain stability, its relative standard deviation (RSD) less than 5%, which can be used as diagnostic indexes for the oil source fingerprint identification. For the PAHs indicators, the 81 Cflu and δ13Cph of the two types of oils were distributed at -27.476‰～-26.583%o and -26.482‰～-21.914‰, each focusing on a certain range, use of δ13Cflu and δ13Cphe as double indicators can distinguish different samples of weathering oil in the long-term weathering.Studies have shown that stable isotope tracing oil as a source of technical means can be used to identify the source of oil after weathering. When and GC-MS techniques exhibit limitations, stable carbon isotope ratio can be the diagnostic indexes for further analysis and complementary.