An Examination of the Fate of Nigerian Crude Oil in Surface Sediments of the Humber Estuary by Gas Chromatography and Gas Chromatography-Mass Spectrometry

Abstract The hydrocarbon composition of surface sediments at two lithologically different sites in the Humber Estuary (U.K.) has been examined by gas chromatography and gas chromatography-mass spectrometry. The sediments were sampled 5, 7 and 12 months after the accidental spillage of 6000 tonnes of a Nigerian light crude oil into the estuary from the tanker “Sivand”. The occurrence of distinctive marker compounds in the Nigerian oil facilitated the identification of residues of the “Sivand” cargo in the sediments up to 12 months after the spill. Interpretation of chromatograms revealed several other sources of hydrocarbons contributing to the sediments including those from algae, higher plants and fossil fuel combustion products. Field observations and laboratory studies indicated that the latter compounds were less readily biodegraded in sediments than the oil-derived hydrocarbons. Possible reasons are discussed.