Gravel beaches trapping 20,000 gallons of oil - The Whig Standard - Ontario, CA

An estimated 20,000 gallons (75,700 litres) of crude remain in Prince William Sound, even though oil remaining after the nearly 11-million-gallon (41.64-million-litre) spill had been expected to biodegrade and wash away within a few years.
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Boufadel and his team dug about 70 pits between three feet and five feet (90-centimetres and 150-centimetres) deep on six beaches during summers from 2007 to 2009. His report focuses on data collected on Eleanor Island, about 15 miles (24 kilometres) away from Bligh Reef where the Exxon Valdez grounded on March 24, 1989.

Peter Hagen, program manager for Exxon studies for the National Oceanic and Atmospheric Administration, said Boufadel's study is a continuation of previous work that began in 2001 when 9,000 pits were dug around the sound, confirming the presence of oil.
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Boufadel's study was funded by a $1.2 million, three-year grant from the Exxon Valdez Oil Spill Trustee Council. The council was formed after the environmental disaster to oversee restoration of the sound.

WHOI : Oceanus : While Oil Gently Seeps from the Seafloor

Oil naturally leaking into the ocean offers a 'laboratory' to study accidential spills
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I had learned about natural oil seeps in graduate school, and I knew that they account for about 50 percent of oil that ends up in the coastal environment. That’s five times as much oil as is delivered by accidental spills.

The Santa Barbara seeps, for example emit 5,280 to 6,600 gallons (nearly 20 to 25 tons) of oil per day, and natural seeps have been active for hundreds to thousands of years. Local Native Americans used the oil to waterproof their boats. But I just didn’t appreciate how spectacular they were and what a powerful opportunity they provided to study oil spills.