Weathering Characteristics of Crude Oils from Dalian Oil Spill Accident, China

Weathering experiments under natural conditions were performed after Dalian oil spill accident on July 16, 2010. The weathering effects on n-alkanes, biomarkers and polycyclic aromatic hydrocarbons (PAHs), and the stability of diagnostic ratios (DRs) were researched. Results demonstrated that: (1) Weathering had obviously effects on the distributing of n-alkanes, and commonly used DRs for n-alkanes (e.g. C17/Pr, C18/Ph, Pr/Ph) changed seriously. (2) The DRs of biomarkers demonstrated good stability, which were useful for weathering oil spill identification. (3) PAHs and alkylated homologues were also influenced by weathering, naphthalenes weathered fastest, followed by phenanthrenes.