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With the rapid development of offshore oil exploration and offshore oil transport, oil spills continue to occur, causing serious damage to marine life and marine natural resources. Understand the weathering of the oil spill and identify sources of oil spills, it is extremely important for pollution damage assessment and liability disputes. Whether oil from different origins, or different oil refining process, they have the molecular characteristics significantly different from other oil, with significant difference between the molecular characteristics known as the \The chemical composition of oil spill into the environment through a series of weathering, including volatile, dissolving, dispersing, emulsification, photochemical oxidation, microbial degradation, these effects will reduce petroleum hydrocarbon concentrations of sediment and water and change the oil . Thus increasing the difficulty of the residual oil was identified impact on the environment. Collected at the scene just rely on oil spill weathering oil analysis oil spill weathering law is not enough, how active mastery of the system oil spill of various factors on the weathering of the oil spill law, for accurate identification of the oil spill source play a crucial an important role. Analog device through a special oil spill weathering of heavy fuel oil, light fuel oil, marine fuel oil three oil weathering experiments over the same period, the use of gas chromatography - mass spectrometry (GC-MS) in the weathered samples n-alkanes, polycyclic aromatic hydrocarbons, biological markers were detected spectrum and characteristics, the ratio of the change of the weathering of the oil law and common characteristics. Kind of oil spill samples collected at the scene of the suspected source of oil and other oil contrast marker analysis, the comparison further determine the oil spill markers, provide a scientific basis for the identification of oil source . The results of this study show that: (1) alkanes characteristic ratio C17/Pr, C18/Ph, Pr / Ph, (C19 C20) / (C21 C22) is more obvious, the differences between the different oils for unweathered oil between the differential has an important role. And relatively mild weathered time (7 days), the number ratio is more stable, can be used as the oil spill identification indexes. (2) polycyclic aromatic hydrocarbons (PAHs) ratio C2D/C2P, C3D/C3P, ΣP / (ΣD ΣP) the moderate weathering time (30 days), remained stable, as the oil spill identification indicators the C1D (m / z = 198), C1P (m / z = 192) as a mild weathered Identification Index. (3) cycloalkanes biomarkers has remained stable, and can be combined with other indicators as a basis for identification of moderate and severe weathering oil ratio within the range of the weathering time. (4) the five categories of PAHs, naphthalene weathering speed the fastest, followed by fluorene, dibenzothiophene class Philippine class, the flexor class components difficult to weathering. (5) three kinds of oil due to the physical properties and the relative content of the different nature of different characteristic ratios of variation and weathering speed there are some differences. (6) through the use of n-alkanes (including pristane, phytane) feature ratio of the absolute difference between the average, as well as polycyclic aromatic hydrocarbons and biomarkers characteristic ratios t-test analysis to identify the actual oil spill making oil spill identify more scientific.
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