Exxon Valdez: What Have We Learned?
INTRO: Scientists have learned some valuable lessons in the ten years that they've been studying the Exxon Valdez oil spill in Alaska's Prince William Sound--not the least of which is that spilling oil is a bad idea. Arctic Science Journeys reporter Doug Schneider has more.
STORY: In the days after the Exxon Valdez ran aground in Prince William Sound, Alaska--as 11 million gallons of oil spilled into the blue-green water--public pressure to clean it up became as thick as the oil itself. Molly McCammon is the executive director of the Exxon Valdez Oil Spill Trustee Council, the group established to monitor recovery of the sound.
McCAMMON: "If you could have seen Prince William Sound in the spill area that first year after the spill, the native people call it the "day the water died." I mean, it was overwhelming. You could look at it and you would think this place is dead forever. It will never recover. That would be your immediate reaction. There was so much emotional pressure to get that oil off."
Public pressure to act quickly manifested itself in several ways. One of those ways was to use an unproven technique in which hot water was pumped onto the beaches in a largely unsuccessful attempt to push oil back into the sea. There it could be pumped into barges. But according to Stan Senner, chief scientist with the trustee council, the hot water did more harm than good.
SENNER: "Where there were intensive cleanup efforts, particularly hot water washes, we've seen recovery in those areas lagging behind. In the case of the hot water wash, clearly what happened there was that as the oil was removed by high pressure and hot water, they not only had the injury from the spill, they essentially cooked a lot of the intertidal plants and animals. I wouldn't call it a mistake. They might still use treatments like hot water washes, but I think they would use them more selectively."
Scientists who've studied the impact of the spill on the region have learned other lessons as well. Those lessons are being shared at a meeting of scientists in Anchorage, Alaska, this month to mark the tenth anniversary of the spill.
Of surprise to scientists was just how long oil stayed toxic in the marine environment. Stan Senner says that may be because Alaska's cold subarctic waters caused oil to break down much more slowly. He says the lingering affects of oil may be harming salmon, sea otters and other species.
SENNER: "The overall pink salmon population is doing well. But there is concern about localized toxic effects of lingering oil in intertidal spawning areas. Trustee council researchers have shown that even very low concentrations of hydrocarbons from weathered oil can have toxic effects on the early life stages of pink salmon and herring."
Chemicals called dispersants that break up oil were used only sparingly during the Exxon Valdez cleanup. In the next major oil spill, dispersants may play a larger role, says Stan Senner.
SENNER: This is one that's not universally accepted, but there's a movement in this direction. When you have oil in the water, it's really important to prevent it from reaching shorelines, where the impacts are most likely to be the greatest. What that argues for is a quick use of dispersants to spread that oil around, to get it highly diluted in the water column. Although that has its own concerns and cautions, it's probably preferable to letting huge volumes of oil pile up on shorelines where you then have these intensive cleanup programs and in some cases lingering oil a decade later."
Still, perhaps the most important lesson--other than the need for prevention--is just how hard it is for scientists to distinguish between changes caused by the oil spill and changes caused by other factors, such as logging, overfishing, and natural changes in the environment. It's likely that scientists will try to sort these impacts out for years to come.
OUTRO: From the Sea Grant Program at the University of Alaska Fairbanks, this is Doug Schneider with Arctic Science Journeys.
Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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