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Distinguishing “Background” Hydrocarbons from Contamination Using Chemical Fingerprinting

Background hydrocarbons, derived from both natural and anthropogenic sources, exist at some level in all environments. In some of these, particularly soils and sediments, the background hydrocarbons can be confused with authentic contamination and increase the measured concentrations of total petroleum hydrocarbons (TPH) or regulated hydrocarbons (e.g., PAH). Therefore, the unrecognized presence of background hydrocarbons has the potential to erroneously increase the liability due to any authentic contamination. Chemical fingerprinting of the extractable hydrocarbon fraction provides a means to recognize the occurrence of background hydrocarbons and a means to account for them when assessing the source(s) of authentic contamination. In this paper, the issue of background hydrocarbons is presented, including several examples of the chemical fingerprints of common naturally occurring and anthropogenic hydrocarbons that are found in soils and sediments.