Toxic Orca_Level of PCBs in whale raises alarm

Dead orca is a 'red alert'

Very high level of PCBs in whale raises alarms

Tuesday, May 7, 2002

By ROBERT McCLURE
SEATTLE POST-INTELLIGENCER REPORTER

The orca found dead on the Olympic Peninsula earlier this year carried a level of contaminants that was among the highest -- if not the highest -- ever measured in killer whales, laboratory tests show.

The 22-foot-long female orca was so full of polychlorinated biphenyls that when scientists first attempted to test her fat, the result was too high for the machines to read it.

"She basically knocked our instruments off," Gina Ylitalo, a researcher for the National Marine Fisheries Service, told fellow scientists at a recent seminar. "We had no idea we'd see these levels."

The PCB level found in the orca is dozens of times higher than concentrations known to affect the growth, reproduction and immune system of another marine mammal, the harbor seal.

Although the toxic chemical's effect on orcas isn't as well-known, researchers believe orcas are affected in much the same way.

The super-high reading on the Dungeness Spit whale surprised even scientists who have tracked orcas for years and were well aware of their PCB burdens. It also adds new urgency to old questions about pollution of the oceans and bays of the West Coast, including Puget Sound.

What killed the orca remains a mystery. There were no obvious signs of disease.

The orca had been seen by scientists only once before, in September 1996, about 10 miles off the coast of Coos Bay, Ore.

The initial test had to be aborted because of the staggering PCB levels. Scientists recalibrated the machine so it could read a higher concentration.

A second test using another method produced a similar result.

The results Ylitalo reported at last week's seminar have yet to be written up and forwarded to the fisheries service's higher-ups.

Once that happens, they will be incorporated into a full report on the orca's death, said Brent Norberg, the fisheries service's marine mammal coordinator.

PCBs were used widely across North America as coolants and lubricants for electrical equipment and in other industrial uses until they were banned in 1977. Because they persist a long time in the environment without breaking down, PCBs have been spread extremely far -- even to remote Arctic locations rarely visited by people.

The levels being discovered in animals here are worrisome, researchers say.

"We're trying to figure out where these darn PCBs are coming from," said Peter Ross, a marine mammal toxicologist with the Canadian government's Institute of Ocean Sciences in Sidney, B.C. "Puget Sound is a PCB hot spot in the regional environment."

PCBs dumped in Puget Sound years ago appear to continue to enter the food chain, Ross said. This may help explain why populations of harbor seals in the region have not rebounded as quickly as those along the Pacific Coast and in the Strait of Juan de Fuca.

In orcas, studies have shown that adult females may transfer up to 90 percent of their PCBs and other contaminants, such as DDT, to their first-born calf.

Babies are hit with toxins in the womb and in their mothers' milk just as their organs are developing. Some of these chemicals mimic estrogen, a human hormone, and at high levels are likely to be wreaking havoc with the female orcas' reproductive cycles as well as young orcas' development, researchers believe.

"It's very poignant," said researcher Ross.

It is unclear whether the dead orca found in January at Dungeness Spit ever had a calf.

"She's really kind of odd. We wouldn't expect a reproductive female to have a level that high, but with levels that high, we wonder if she was able to reproduce," said Ylitalo, the fisheries service researcher.

PCBs weren't the only contaminants measured in the orca, said John Stein, director of the Environmental Conservation Division of the fisheries service's Northwest Fisheries Science Center.

"This animal had contaminants we did not expect," Stein said, including some related to pesticides.

Orcas pick up contaminants primarily through the food they eat. The contaminants start out at the bottom of the food chain in microscopic plants and animals that are eaten by larger animals.

The Dungeness Spit whale was a "transient" -- ranging up and down the coast, eating seals, porpoises and other marine mammals. By contrast, the "resident" killer whales that return each year to Puget Sound and the waters around Vancouver Island primarily eat fish.

If you're an orca, "it doesn't really matter how close you are to agriculture or industry or polluted areas," Ross said, "it's a question of what you eat."

PCBs and some other toxins accumulate at higher levels in transient orcas because they eat prey that is higher up the food chain than the resident whales.

An orca can eat up to one-twentieth of its body weight in prey each day, meaning it eats the equivalent of its own body weight every 20 to 30 days, Ross said.

Ylitalo told scientists at the seminar that the PCB level in the Dungeness Spit orca was about 1,000 parts PCB per million parts of fat.

By contrast, the amounts reported by Ross two years ago in the most comprehensive study to date showed that female transient orcas averaged 58 parts per million. Males averaged 251 parts per million, or roughly one-quarter of the level found in the Dungeness Spit orca.

Ross' study used a pneumatic dart with a stainless-steel tip to take samples of fat from orcas that swim in the coastal waters around Washington and British Columbia. That study placed PCBs levels in local orcas among the highest measured in marine mammals anywhere in the world.

Marine-mammal researcher John Calambokidis of the Cascadia Research Collective said he is eager to read the fisheries service's upcoming official report on the tests.

Assuming the PCB concentrations Ylitalo reported are correct, he said, "It represents a level that I wouldn't say is off the scale for killer whales, because some very high levels have been measured in the past, but it does seem to represent the upper end."

Calambokidis said 1,000 parts per million would rank among the highest PCB levels measured in orcas and could turn out to be the highest.