Evaluation of diagnostic ratios of medium and serious weathered oils from five different oil sources

摘要

Laboratory experiments were conducted to simulate oil weathering process, a medium to long term weathering process for 210-d, using samples collected from five different oil resources. Based on relative deviation and repeatability limit analysis about indexes of these samples, the results show there had been significant changes in diagnostic ratios among the initial and weathered samples of different oils during this process. Changes of selected n-alkane diagnostic ratios of all oil samples displayed more obviously than diagnostic ratios of terpanes, steranes and PAHs in this process. Almost all selected diagnostic ratios of terpanes, steranes and PAHs can be efficiently used in tracking sources of hydrocarbon pollution, differentiating from the n-alkane diagnostic ratios. In these efficient diagnostic ratios, only four ratios maintained good stability in the weathering processes and are more suitable because their relative deviation (RSD) are lower than 5%.