ENVIRONMENTAL NEWS

Slow recovery after Exxon Valdez oil spill

T en years after the fateful Exxon Valdez oil spill in Alas­ka's Prince William Sound,

the Sound's ecosystem is re­bounding, but only two species have fully recovered from the spill's impacts, according to a re­port released in February by the Exxon Valdez Oil Spill Trustee Council. The council is a coalition of federal and state agencies cre­ated to oversee restoration and species monitoring efforts.

Their assessment is at odds with Exxon Corp.'s perception, however. In a statement marking the spill's 10th anniversary, Exxon maintained that "the environ­ment as a whole and the species damaged by the spill are healthy and robust. Further, the vast ma­jority of the thousands of species in the Prince William Sound eco­system were either never affected by the spill or have since fully recovered."

All told, some 11 million gal­lons of oil flowed into the Sound from the wreck, affecting 1300 miles of shoreline and killing an estimated 250,000 seabirds, 2800 sea otters, 300 harbor seals, 250 bald eagles, and as many as 22 killer whales. The spill also harmed unknown billions of salmon and herring eggs and lar­vae, as well as comparable num­bers of intertidal and subtidal plants and animals, according to the Trustee Council.

Out of 24 species that suffered some form of population level decline or sublethal effects from the spill, eight still are not show­ing signs of recovery. The recov­ery status is unknown for four others—part of the reason being that there are very little good baseline data on the conditions that existed before the spill.

Nevertheless, a decade's worth of scientific study now contra­dicts the assumption that the oil's

More than $2 billion were spent over four summers to clean up after the Exxon Val­dez oil spill; the results are still in con­tention.

toxic fractions would evaporate off quickly or degrade, as the oil weathered. "A new finding is showing that not only is the weathered oil still very toxic, but that it's also very toxic at low lev­els," said Stan Senner, the Trustee Council's science coordinator.

This discovery means that oil is still leaching from a number of beaches as storms rearrange the boulders that protected these de­posits, creating potential for lin­gering effects, particularly on spe­cies that spawn or feed in the intertidal zone. Stanley Rice, a senior scientist at the National Oceanic and Atmospheric Admin­istration's (NOAA's) Auke Bay Lab in Juneau, likened the overall risk posed by the lingering oil resi­dues to that of a land mine. "If you happen to be the one step­ping on [these leftover oil depos­its], it's going to affect you. But once that oil's been exposed and leaked out, it won't leak out again, so the situation's going to

keep getting better." However, some species still face a low level of risk from the residual oil, he said.

These species include mussels, whose beds lie on contaminated soft sediments, and the juvenile sea otters and harlequin ducks that prey on them. Both of these predators show evidence of expo­sure to hydrocarbons in their blood chemistry. Harlequin ducks in oil-contaminated parts of the Sound also show signs of signifi­cantly decreased overwintering survival compared to birds on unoiled Sound habitats, Senner said. While Exxon Valdez oil is not the proven culprit, "there's a sus­picious correlation," he added.

Likewise, laboratory studies have demonstrated that exposure to hydrocarbons can have toxic effects on the early life stages of pink salmon and herring, both of which spawn in the intertidal zone, and induce expression of viral disease in adult herring, Senner said. "Lab research found effects [at levels] as low as 0.4 parts per billion (ppb) for herring and 1 ppb for salmon eggs," said Bruce Wright, NOAA's liaison to the Trustee Council. "That's just a few drops of oil in an Olympic-sized swimming pool," Wright noted.

These findings too, however, have been a point of contention between government scientists and Exxon scientists. "The amount of oil remaining on beaches can only be found in a few isolated locations, so it's sort of counterintuitive to say that these minute amounts are having any effect against the background of ongoing human activities like fishing, tanker traffic, and out­board motors that add petroleum products to the environment," said David Page, a chemistry pro­fessor at Bowdoin College in Maine, who has conducted

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studies for Exxon. "They're mak­ing the assumption that any change that they see is somehow linked to the oil spill," Page said.

Indeed, NOAA and the Trustee Council admit that other factors such as rising temperatures in ocean waters, the availability of

prey, predation by other species, human fishing pressures, and the loss or degradation of habitat make it difficult to tease out oil spill impacts from natural im­pacts on species recovery. But with Exxon Valdez oil still out there in western Prince William

Sound, it makes sense that oil is still causing stress to plant and animal species in that region, Wright said. "And it's important to note that the effects we're seeing are occurring in [streams that were oiled], not unoiled ones," he added. —KRIS CHRISTEN

Technology gaps exacerbate vulnerability to heavy oil spills Though February's burning of the oil-laden freighter grounded off the Oregon coast was not a com­plete success, most observers be­lieve the air pollution it generated was worth the ocean life it saved. The ill-fated ship's plight illus­trates key technology gaps that may make vessels transporting heavy fuel more vulnerable and spills harder to clean.

A National Research Council (NRC) report due out this spring will address the need for new heavy oil spill cleanup and pre­vention technologies, said Keith Michel, president of Herbert En­gineering, a firm involved in ship design and a member of the NRC's Committee on Marine Transportation of Heavy Oil. Al­though he refused to comment on specifics, he acknowledged that the report may call for ship-design modifications to decrease the chance that heavy oils get spilled.

According to NRC research, 25% of the petroleum products recently spilled in U.S. waters are heavy oils, which the report's au­thors define as including asphalts and coal tar, as well as the resid­ual oils increasingly used as power plant fuel. NRC's research shows that heavy oils compose only 17% of the oil transported in U.S. waters, Michel said.

The fact that such a high per­centage of spills involve heavy oil definitely merits attention, said John Torgan, a biologist for Save the Bay, Rhode Island's largest environmental group. Ports across the country are being ex­panded in a competition "to get the biggest and largest ships in," he said. "When we increase the level of shipping, we may in­crease the risk of spills. It doesn't take an oil tanker to cause an oil spill."

The New Carissa was intentionally set afire in a failed attempt to burn the 400,000 gallons of fuel she was carrying. (Cour­tesy U.S. Coast Guard)

Groundings cause 62% of ocean oil spills, while 48% of in­land water spills result from colli­sions or rammings, according to Michel. The 400,000 gallons of fuel inside the New Carissa when she first ran aground in Oregon were vulnerable to spillage be­cause they were carried in an area below the cargo space pro­tected only by the ship's outer shell. This is a "common" freighter fuel tank design, accord­ing to a Chamber of Shipping of America spokesperson. In re­sponse to the incident, Oregon senator Ron Wyden vowed to in­troduce legislation allowing the U.S. Coast Guard to refuse entry to foreign-flagged vessels, like the New Carissa, if there are safety concerns.

When heavy oils are spilled, cleanup presents distinct chal­lenges. Instead of forming con­tinuous slicks, they tend to break up into tarry balls. Depending upon the currents, density, and turbidity of the water in which they land, these tarballs may sink, float, or "bounce around in the water like a lava lamp," said Barbara Davis, an environmental health scientist for EPA's Oil Pro­gram Center. In stormy condi­tions, tarballs can travel hun­dreds of miles, said Jacqueline

Michel, vice president of science and technology for Research Planning, Inc., a firm that pro­vides expert oil spill support to the National Oceanic and Atmo­spheric Administration. She is also a member of the NRC's Committee on Marine Transpor­tation of Heavy Oil, (but is not related to Keith Michel).

Sinking heavy oils pose a sig­nificantly greater risk to bottom-dwelling fish and shellfish, Jac­queline Michel said. Because spilled heavy oils weather more slowly than lighter oils, the poly-aromatic hydrocarbons that they introduce may harm all fish— especially vulnerable young hatchlings—for a longer period.

Even heavy oils that float—such as the 72,000 gallons of heavy oil that die New Carissa dumped into two estuaries that are home to more than $10-12 million worth of Oregon oysters, as well as a variety of clams and Dungeness crabs— behave differentiy than lighter crudes. Their tendency to break up makes diem much harder to lo­cate, said Jacqueline Michel. They often sink just below the surface after being overwashed by waves, she said.

The state-of-the-art for instru­ments capable of detecting sub­merged tarballs is "very poor," said Mervin Fingas, chief of Envi­ronment Canada's Emergencies Science Division. Furthermore, the oil companies' reduced reve­nues resulting from today's low oil prices make it unlikely that the needed detection technology will be developed any time soon, Jacqueline Michel said. The Coast Guard is nonetheless beginning to assess the need for this detec­tion equipment, said Ken Bitting, program manager for the agency's Comprehensive Marine Environ­mental Protection Program.

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