Applications of biomarkers for identifying sources of natural and pollutant hydrocarbons in aquatic environments

Over the past decade, many thousands of compounds have been identified in crude oils using high resolution capillary gas chromatography-mass spectrometry (GC-MS) and other techniques, Some of these compounds have distinctive chemical structures which are closely related to the organic compounds produced by plants, bacteria and algae. These 'biomarkers' are used in petroleum exploration to identify the likely source rocks from which different oils were derived. The same compounds can also be valuable for identifying sources of petroleum contamination in the marine environment, for recognising natural constituents and as tracers for physical and biological processes that affect hydrocarbon distributions such as dissolution, evaporation, biodegradation, bioturbation, and uptake by biota. Some applications of petroleum biomarkers to environmental studies of hydrocarbon pollution are reviewed in this paper.