Study describes lingering damage from oil spill

But Exxon Mobil disputes Exxon Valdez findings

December 19, 2003|By Kenneth R. Weiss | Kenneth R. Weiss,LOS ANGELES TIMES

Hidden pools of oil left over from the Exxon Valdez spill 14 years ago continued to damage the Alaskan coastal environment for a decade, killing pink salmon eggs and retarding the population growth of sea otters, harlequin ducks and other wildlife, a new study says.

The 14-year study published yesterday in the journal Science points out that effects of the 11 million-gallon spill into Prince William Sound extended well beyond the initial deaths of 250,000 oiled seabirds, 2,800 otters and 300 harbor seals.

The residual oil grew more toxic and harmed the coastal environment far longer than expected, the study says. These oily pockets are tucked beneath boulders or buried below gravel and mussel beds and have escaped sunlight, oxygen and waves that would normally break them down.

"Because the Exxon Valdez spill happened in a biological wonderland of sea otters and harlequin ducks, there has been a huge amount of research," said Charles H. Peterson, the paper's lead author and a University of North Carolina marine biologist. "Things we have dismissed as sublethal effects actually translate into significant decline in wildlife."

The study compared the recovery of sea otters on heavily oiled shores of northern Knight Island with another island in the region that was not coated during the spill. The population of sea otters that forage around Knight Island is half of what it was before the spill, while the population at the other island doubled between 1995 and 1998.

Otters suffer chronic exposure to toxic oil residue by eating contaminated clams and by digging into contaminated sandy ocean bottoms, the study said.

Written by seven university and government scientists, the study was attacked as a bunch of "cartoon depictions" by Exxon Mobil Corp. officials.

"What science has learned in Alaska and elsewhere is that while oil spills can have acute short-term effects, the environment has remarkable powers of recovery," said Frank Sprow, Exxon Mobil's vice president of safety, health and the environment.

After Exxon Mobil spent $2.2 billion to clean up Prince William Sound and another $1 billion for environmental studies and conservation programs, it became clear that any remaining oil was safely encapsulated, he said.

"If it was leaching into the environment in ecologically meaningful quantities, it would be gone after 14 years," Sprow said.

The study, which included representatives of the National Marine Fisheries Service, the U.S. Fish and Wildlife Service, and the U.S. Geological Survey, says that "disagreements exist" between scientists funded by Exxon and those funded by the government. Furthermore, the answers to some ecological questions remain uncertain.

"Nevertheless," the study's authors write, "these uncertainties do little to diminish the general conclusions: oil persisted beyond a decade in surprising amounts and in toxic forms."

One particularly disturbing finding was that partially weathered oil appeared to be more toxic to fish than fresh.

The scientists found that residual oil killed the embryos of pink salmon for at least four years after the spill. Pink salmon are a key part of the food web in Alaska, including a prominent part of the diet for resident killer whales.

The Los Angeles Times is a Tribune Publishing newspaper.

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