A retrospective chemical and biological study was carried out in Camden Bay, Alaskan Beaufort Sea, where single exploratory oil wells were drilled at two sites more than two decades ago. Barium from discharged drilling mud was present in sediments at concentrations as high as 14%, ~200 times above background, with significantly higher concentrations of Ba, but not other metals, within 250 m of the drilling site versus reference stations. Elevated concentrations of Cr, Cu, Hg and Pb were found only at two stations within 25 m of one drilling site. Concentrations of total polycyclic aromatic hydrocarbons (TPAH) were not significantly different at reference versus drilling-site stations; however, TPAH were elevated in Ba-rich layers from naturally occurring perylene in ancient formation cuttings. Infaunal biomass and species abundance were not significantly different at reference versus drilling-site stations; infauna were less diverse at drilling-site stations. Our assessment showed that discharges from single wells within large areas caused minimal long-term, adverse impacts to the benthic ecosystem.
- Polycyclic Hydrocarbons, AromaticAlaskaArctic RegionsEnvironmental MonitoringEnvironmental PollutantsExtraction And Processing IndustryGeologic SedimentsMetals, HeavyOceans And SeasPetroleumPolycyclic Aromatic HydrocarbonsRegression AnalysisRetrospective StudiesSpectrophotometry, AtomicAlaskan ArcticOffshore Oil DrillingBariumMetalsPAHBenthic Infauna