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An aerial photo of the Exxon Valdez oil spill.

Oil leaks from the Exxon Valdez after it ran aground in March 1989; 11 million gallons of crude eventually leaked into Prince William Sound, Alaska.

PHOTOGRAPH BY NATALIE B. FOBES, NATIONAL GEOGRAPHIC

Jane J. Lee

National Geographic

Published March 24, 2014

Twenty-five years after the Exxon Valdez oil spill set off one of the most devastating environmental disasters in U.S. history, scientists say that a surprising amount of oil still clings to boulder-strewn beaches in the Gulf of Alaska.

And that oil could stick around for decades to come.

Monday marks the 25th anniversary of the spill, when a tanker ran aground on Bligh Reef in Prince William Sound (map). The accident wiped out herring and salmon runs. And some of the affected wildlife, like sea otters and pink salmon, are still recovering.

The latest findings on lingering oil came last month, when scientists announced that spilled oil in the Gulf of Alaska still has most of the same chemical compounds as oil sampled 11 days after the accident. (See "Exxon Valdez Anniversary: 20 Years Later, Oil Remains.")

The scientists presented evidence of a lingering, foamy, mousse-like emulsion at a major ocean science conference in Hawaii.

The oil's presence in areas that were cleaned right after the spill points to a need to monitor certain environments long after the visible effects disappear, the researchers say.

It's Like Mayonnaise

There are two main reasons why there's still oil on some of the beaches of the Kenai Fjords and Katmai National Parks and Preserves in the Gulf of Alaska, explains Gail Irvine, a marine ecologist with the U.S. Geological Survey and lead researcher on the study.

When the oil first spilled from the tanker, it mixed with the seawater and formed an emulsion that turned it into a goopy compound, she says.

"When oil forms into the foam, the outside is weathering, but the inside isn't," Irvine explains. It's like mayonnaise left out on the counter. The surface will crust over, but the inside of the clump still looks like mayonnaise, she explains.

When that foamy oil met the boulders and cobbles of beaches in the Gulf of Alaska, it plopped down between and under the rocks, and it's still there.

A photo of oil seeping from underground from the Exxon Valdez oil spill
Oil seeps from underground in a hole dug on a beach on Eleanor Island, Alaska, on May 5, 2010.
PHOTOGRPAH BY LINDSAY CLAIBORN, REUTERS

Protected by Boulders

The boulders on these beaches don't move very much, says Christoph Aeppli, a marine environmental chemist at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine. On their most exposed site, the boulders moved less than 3.3 feet (a meter) from 1994 to 2012.

"That stability is what has allowed the oil to persist," Irvine says, even after the beaches were steam-cleaned.

Researchers aren't sure how much oil remains ensconced under these boulders—that would require a different kind of study. "We think it's low levels," says Irvine. "Quite frankly, I didn't think [oil] would be there because it's been so long."

Nonetheless, the oil is there—and is leaking out. Irvine and colleagues collected and tested mussels near these boulder fields and found low levels of Exxon Valdez oil in their tissues.

Irvine says the levels are so low that it probably isn't a cause for concern for the animals. She says the main takeaway from the study is the fact that surprisingly fresh oil can linger in certain environments long after a spill has been cleaned up.

And that means that monitoring an environment after an oil spill isn't a matter of weeks or months but of years and even decades.

Follow Jane J. Lee on Twitter.

9 comments
Kaitlyn Anstett
Kaitlyn Anstett

I live here in Alaska and this still widely affects our nature. My mother was here when it happened and was very distraught. A few of my friends and I are trying to come up with a fundraiser to try and dispose of the oil on and off land.

Robert Petretti
Robert Petretti

Meanwhile, a fresh oil spill off the coast of Texas. 

Rob Foster
Rob Foster

"When oil forms into the foam, the outside is weathering, but the inside isn't," Irvine explains. It's like mayonnaise left out on the counter. The surface will crust over, but the inside of the clump still looks like mayonnaise, she explains.

KENNETH LANE
KENNETH LANE

The remedy for this brand of Corporate abuse is honest elections--------not even remotely likely in the United States.

Gary Sheldon
Gary Sheldon

Exxon has still not acted responsibly from this accident. Boo To Exxon/Mobil

Corbett French
Corbett French

Agreed.  As sad as it is, it would be nice to keep ecologist, geologist, microbiologist, marine biologist, organic chemist, and inorganic chemist eyes on all of this.   There is so much that we can learn from this.

Miguel Rodriguez
Miguel Rodriguez

As sad as this is, is very important to keep an intensive field investigation on the Alaska's coast near the oil spillage from the Exxon Valdez. We can learn a lot about the long term consecuences of this kind of enviromental tragedies. And that is unvaluable to prevent or remediate future incidents.

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