Poisoning the Polar Bear
Humans Leave Toxic Footprint in Remote Area

MARLA CONE / Los Angeles Times 5jul03

SVALBARD, Norway — Born at Christmastime, cradled in snow, two newborns are sleeping and suckling, protected by one of the fiercest creatures on Earth.

The brothers were born blind, toothless, a pound apiece, as feeble as kittens. For four months they will nestle in a den carved by their mother on the bleak banks of a frozen sea. They will gorge themselves on rich, fatty milk, doubling their weight every few weeks.

Etched by harsh winds and ancient glaciers, closer to the North Pole than to Oslo, Svalbard is a brutal place, unforgiving of weaknesses. From the moment of birth — even conception — animals here struggle against the odds. Most polar bears die before their first birthday.

Yet it is an unnatural threat — a human-made one — that is intruding upon this polar-bear nursery. Even before they leave the safety of their dens, the cubs carry more pollutants than most other creatures on Earth, having ingested industrial chemicals from their mother's milk.

Recent scientific studies suggest that extraordinary loads of contaminants have migrated to the Arctic and are weakening polar bears and other animals, jeopardizing their survival. Like a giant sink, the remote, icy realm surrounding the North Pole — particularly the Norwegian archipelago of Svalbard — collects many of the world's most toxic chemicals, especially banned industrial compounds called PCBs and pesticides such as DDT.

Scientists also have found that a relatively new contaminant — flame retardants that are still widely applied to furniture and construction materials in the United States — has made its way to the North Pole.

In a phenomenon called the grasshopper effect, chemicals repeatedly evaporate and fall to the ground, hopping across the world in this fashion. Riding ocean currents or northbound winds, they end up above the Arctic Circle.

Once in the Arctic, the chemicals stay there. They build up in ice and ocean sediment, enduring for decades — perhaps centuries — and accumulate in the fat of animals, peaking at the top of the food chain.

As a result, the Arctic's most voracious predators are among the most contaminated living organisms ever found. Only Pacific Northwest orcas, Baltic Sea seals and St. Lawrence River belugas have been found with higher doses of PCBs than Svalbard's bears.

Lethal weapons?

Scientists say that the globetrotting contaminants are responsible for an array of symptoms. Recent studies in Norway and Canada show that polar bears' immune cells and antibodies, needed to fight off disease, have been suppressed, and that their levels of testosterone, progesterone, vitamin A and thyroid hormones are altered by PCBs.

Although the evidence is incomplete, scientists think the pollution may be culling Svalbard's older bears and perhaps weakening or killing cubs. Females over 15 years old are rare. Researchers have also come across small numbers of strange, pseudo-hermaphroditic bears, ones with mostly female anatomy but also parts of male anatomy.

"Could you realistically put 200 to 500 foreign compounds into an organism and expect them to have absolutely no effect?" said Andrew Derocher, a Canadian scientist with the Norwegian Polar Institute who has tested about 4,000 bears in 20 years of research in the remote reaches of the Arctic.

"I would be happier if I could find no evidence of pollution affecting polar bears," he said, "but so far, the data suggest otherwise."

Derocher was raised along the lush banks of British Columbia's Fraser River. Claustrophobic in cities, he heads north, far north, whenever he craves wilderness.

Setting foot on Svalbard in 1996, Derocher thought he had found paradise. After researching wildlife in Canada, his longtime dream was to study polar bears in their purest form, to find a population protected from human contact.

Hunting of Svalbard's bears dates to the 16th century, but since 1973, Svalbard has been a national refuge. When Derocher arrived, the population should have fully recovered.

But it wasn't long before he knew something was amiss.

'Dirty dozen'

As early as 1970, Canadian and European scientists discovered that DDT and PCBs were showing up in seals in the far north. Biologists had visited Arctic Canada and Norway to seek "blanks" — samples of animals expected to be free of contaminants. But in fact, their blanks were as dirty as those from some industrialized regions.

Now, all 12 of the "dirty dozen" contaminants considered capable of inflicting the most ecological damage have been detected at significant levels in the Arctic, said Derek Muir, an Environment Canada researcher.

PCBs, used worldwide as insulating fluids in electrical transformers, and chlorinated pesticides such as DDT, toxaphene, dieldrin and chlordane were banned in the 1970s in most industrialized nations but persist in the environment, especially the oceans.

From water to plankton to copepods to cod to ringed seals to polar bears — at each step up the food chain, PCBs increase five- to tenfold in a process called bio-magnification. As a result, a polar bear carries a concentration billions of times greater than water in the Arctic Ocean.

A mother polar bear stores chemicals from a lifetime of exposure in her fat. The concentration peaks during the winter fast when she gives birth — and then she bequeaths it, via her milk, to her cubs.

Because of their thick fat, big appetites and long, multi-stepped food chain, Arctic animals are repositories for toxic compounds, storing more than animals in temperate zones. They also deplete their fat reserves in winter, which concentrates chemicals in their tissues. The levels of PCBs in Svalbard bears are "alarmingly high," peaking at 80 parts per million, said Janneche Utne Skaare, a scientist with Norway's National Veterinary Institute.

On average, they are 12 times more contaminated than Alaskan bears. Masses of air and ocean water pass by the Norwegian islands, dropping off pollutants that hitchhike from Europe, Russia and the East Coast of North America. Svalbard's other top predators, Arctic foxes and birds of prey, also are highly contaminated.

Immune damage

Most of the concerns about Arctic wildlife center on the ability of the contaminants to suppress immune systems and disrupt sex hormones.

Producing a flood of antibodies to fight off viruses and infections is crucial for an animal's survival. But when Svalbard polar bears are exposed to a flu virus in experiments, they cannot muster as many antibodies as Canadian bears, which have far fewer PCBs, according to research by Hans Jorgen Larsen of the Norwegian School of Veterinary Science.

In the North Sea, two distemper epidemics, one last year and one in 1988, wiped out an estimated 38,000 seals. Experts specializing in immunotoxicology say the seals' high PCB levels exacerbated the scope of the epidemic. In tests on captive seals, scientists determined that levels of PCBs only one-fifth as high as those found in some Svalbard bears suppress immunity.

Norwegian scientists also have reported that the bears have altered testosterone and progesterone hormones, which could be reducing their fertility and perhaps causing sexual deformities. Of every 100 Svalbard bears captured, three or four have female and partial male genitalia.

Over the past decade, research on a variety of animals elsewhere, including alligators in Florida, birds in the Great Lakes and fish in Europe, has shown that DDT and other contaminants can mimic estrogen or block testosterone, causing feminized or half-male, half-female animals.

The chemicals also might have led to a missing generation of mother bears. Only 11 percent of Svalbard bears with cubs were over 15 years old, compared with 48 percent in Canada, said Geir Gabrielsen, Norwegian Polar Institute's director of ecotoxicology.

Ross Norstrom, a Canadian Wildlife Service toxicologist who is one of the world's leading polar-bear experts, worries most about the cubs. He said development of their immune and reproductive systems occurs during the first few months after birth, right when they are hit with the blast of PCBs from mother's milk.

The cubs of mothers with a lot of PCBs in their milk are more likely to die during their first year than cubs of mothers with low PCBs, according to research.

An inherent weakness of wildlife toxicology is in proving cause and effect, says Peter Ross, a Canadian scientist. Wild animals face so many variable factors, such as climate and diet, that it is impossible to tease out one factor as the root of a problem. The best scientists can do, he said, is amass evidence, as they have with PCBs. The uncertainty is compounded in Svalbard, where because of its remoteness, scientists don't even have a reliable population estimate or know how often bears die.

Yet Norstrom said after about 15 years of research, scientists are finally on the cusp of proving PCBs are harming Arctic wildlife. "We're at the threshold, in a lot of ways, with polar bears," he said.