Aliphatic and aromatic biomarkers for fingerprinting of weathered chemically dispersed oil.

This study evaluated the applicability of eight types of biomarkers namely, adamantanes, diamantanes, sesquiterpanes, steranes, terpanes, TA-steranes, MA-steranes, and alkylated PAHs, to characterize chemically dispersed oil (CDO) after the 60-day weathering. The stability of diagnostic ratios of the selected biomarkers was evaluated and summarized. The results indicated that the concentrations of biomarkers with low molecular weight, such as adamantanes, diamantanes, and sesquiterpanes, in CDO were markedly affected by weathering and the associated diagnostic ratios were changed extensively. Most of the alkylated PAHs were degraded during weathering as well. These biomarkers thus were not recommended for characterizing CDO. The majority of the terpanes, steranes, TA-steranes, and MA-steranes could be used for weathered CDO fingerprinting due to the relatively stable diagnostic ratios. The findings could help to identify applicable biomarkers for fingerprinting of weathered dispersed oil.