The Fate of the Oil Spilled from the Exxon Valdez

Just after midnight on March 24, 1989, the 987-foot tank vessel Exxon Valdez grounded on Bligh Reef in Prince William Sound (PWS), Alaska, releasing approximately 10.8 million gallons of North Slope crude oil into the Sound. The energetic environmental conditions in PWS and the extensive cleanup activities led to wide dispersion of the Exxon Valdez oil, which simultaneously underwent biodegradation and photooxidation. Although some more refractory residuals of the petroleum (e.g., high molecular weight PAH, resins, and asphaltenes) persist, many of these constituents are not readily distinguishable from other petroleum sources and naturally occurring hydrocarbon residues. We estimate that approximately 20% of the spilled oil evaporated and underwent photolysis in the atmosphere; approximately 50% biodegraded either in-situ on beaches or in the water column; approximately 14% was recovered or disposed; < 1% remained in the water column (except as biodegradation products); approximately 2% remained on intertidal shorelines; and approximately 13% remained in subtidal sediments, mostly in the GOA and again mostly as highly weathered residuals. 60 refs., 3 figs., 2 tabs.