19 June 2003
Polar Bears and Pollution
* Migrating chemicals have made the creatures among the most tainted
anywhere. Researchers brave the Arctic and risk attack to study
Norway — Born at Christmastime, cradled in pure white snow,
two newborns are sleeping and suckling, protected by one of the
fiercest creatures on Earth.
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, snowy banks of a frozen sea. They will gorge
themselves on rich, fatty milk, doubling their weight every few
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
it is an unnatural threat — a man-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
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 Norway's
Svalbard archipelago — collects many of the world's most toxic
chemicals, especially banned industrial compounds called PCBs and
pesticides such as DDT.
have also 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
a phenomenon called the grasshopper effect, chemicals repeatedly
evaporate and fall to the ground, hopping across the world in this
fashion. Riding northbound winds, they end up above the Arctic Circle,
traveling thousands of miles from their points of origin in industrialized
regions. Ocean currents also slowly carry chemicals north.
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
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.
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.
the evidence is incomplete, scientists think the pollution may be
culling Svalbard's older bears and perhaps weakening or killing
cubs. Females more than 15 years old are rare, and the population
seems small. Researchers have also come across small numbers of
strange, pseudo-hermaphroditic bears, ones with mostly female anatomy
but also parts of male anatomy.
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.
would be happier if I could find no evidence of pollution affecting
polar bears," he said, "but so far, the data suggest otherwise."
That Never Melts
is early evening, nine days after the return of the midnight sun,
and the glaciers are casting jagged shadows on the ice below. From
the front seat of a helicopter, Derocher is scanning the ice, looking
for tracks. "There should be lots of bears just waiting for
us here," he says.
has arrived in Svalbard. Brilliant cobalt-blue seawater is shattering
its icy shield, splitting the fiords into patches, like frosty white
lily pads floating on a pond. But in the northern reaches of Spitsbergen,
Svalbard's largest island, the sea never melts. The ice looks as
taut as a bedsheet in some spots, as billowy as a down comforter
in others. The horizon is lost on overcast days as shades of white
vast, silent prairie, 600 miles from the North Pole, is a favorite
spot for polar bear mothers to raise their cubs. Svalbard is home
to about 2,000 bears, 10% of the world population.
450-pound isbjorn, Norwegian for polar bear, has just abandoned
her winter den to begin tutoring her cubs. The mother bear lumbers
along, hunting her favorite prey of ringed seals, leaving a zigzag
path of 12-inch-wide craters followed by the smaller paw prints
of her two sons. A few miles away, Derocher spots the bear family's
telltale trail from 300 feet up. Pilot Oddvar Instanes loops, spins
and straddles the tracks, following their erratic path for several
miles. A seal lounging by a hole in the ice looks up, puzzled by
the helicopter's noisy antics.
about a dozen people on Earth know how to find and catch a polar
bear. The bears' fur is pigment-free, translucent like ice, and
each hair's hollow core reflects light. It is easier to spot their
tracks than to spot the bears. "She's running here," Derocher
says, pointing to a row of bear tracks at the edge of a craggy glacier.
"I think she's ahead of us here somewhere."
the chopper's back seat, Magnus Andersen, his Norwegian colleague,
fills a syringe with a tranquilizer. He injects the colorless liquid
into a dart and screws it onto a shotgun.
mother and cubs are now right below them. The pilot dips to about
six feet over the mother's head, so close they can see the coarse
hair on her back blowing in the wind as she runs. Silently, Andersen
kneels on one leg and opens the door. A freezing blast of air slaps
him in the face. The blades whip up a whirlwind of snow, masking
the helicopter chases the bear, spinning in circles perilously close
to the ground, Andersen leans out the door, tethered by a thin green
cord. He takes aim and fires. The smell of gunpowder wafts through
Andersen says. A dart sticks out of the bear's rump. Precision is
important. If he had hit her in the chest, it would have killed
her as sure as a bullet.
minutes, the mother starts to wobble, but she isn't going down.
Andersen readies another syringe and fires, hitting her in the rump
again. She lies on her stomach, eyes open but still, one paw splayed
back. The cubs nuzzle her, trying to wake her, then curl up beside
her. Peering out over their sleeping mother's back, they are wide-eyed
and curious as the craft lands.
and Andersen step out into the freezing air. They approach cautiously,
their boots crunching in the snow. The men circle slowly around
is 6 feet 3 and 225 pounds. The mother bear is twice his weight,
and a male bear can weigh almost a ton. Derocher and Andersen always
carry loaded .44-magnum pistols on their waists. A few years earlier,
two young tourists were mauled to death in Svalbard while taking
a walk just outside its town of Longyearbyen.
never the bear we're drugging that's dangerous," says Derocher.
"It's always the bear you don't see."
4-month-old cubs are as adorable and innocent as their mother is
deadly. At 45 to 50 pounds apiece, they are about the size of Derocher's
6-year-old daughter and just as harmless. Gloveless, Derocher strokes
one's soft, creamy-white fur, and Andersen holds out a finger for
the other to sniff and lick. These are the first humans these cubs
have seen, and perhaps the last. Andersen gently loops ropes around
their necks and tethers them to their mother. If they were to wander
away without her, they would die.
checks the mother's ear for an identifying tag. "She was caught
once before," he says.
sets down his black toolbox, removes dental pliers and opens the
bear's jaw. Leaning inside her gaping mouth, he deftly extracts
a tooth, a useless pre-molar the size of a cribbage peg that will
be used to confirm her age. She is about 15 years old, and Derocher
wonders if this will be her last set of cubs. Older females like
her are rarely seen denning in Svalbard, even though polar bears
live as long as 28 years in the wild.
is working on her other end, using a biopsy tool to cut a quarter-inch-in-diameter
plug of blubber from her rump. Then he quickly siphons a tube of
blood from a vein in a hind leg. Together, the two scientists stretch
a rope over the mother to measure her girth and length. Then Derocher
and Andersen inject each cub with tranquilizer before taking blood
samples. With a clamp, Derocher attaches a tag marked with identifying
numbers to the cubs' ears. Drops of blood drizzle onto the snow.
kneels beside the mother and milks her like a cow to get a small
sample of the creamy liquid she is feeding her offspring. The milk,
fat and blood will be analyzed at a lab for a suite of chemicals.
Then he gently lifts her giant head and puts her lolling tongue
back in her mouth. Instanes paints a big brown X on her rump, signaling
that she shouldn't be bothered again this year. The cubs are left
snoring, all eight paws splayed on the snow. The threesome will
sleep two hours, then shake off the drowsiness and go their way.
and Derocher pack up their toolbox and walk back to the helicopter.
It has been 40 minutes since they landed.
April for a full month, the scientists work in this frigid wilderness-turned-laboratory,
tranquilizing 60 to 100 bears to monitor their health and test for
contaminants. It is dangerous business for man and bear. But scientists
say it is critical for understanding how wild animals are faring,
how much chemicals they carry in their bodies.
Derocher says, "we would blindly stumble into extinction. My
job is to make sure polar bears are around for the long term."
bad weather sets in or the helicopter breaks down, he and his team
are stranded on the ice. Or worse. On a spring day in 2000, two
colleagues tracking bears in Canada were killed in a whiteout, which
occurs when clouds descend and the ground and sky merge. Their helicopter
crashed into a glacier.
when caught in whiteouts, Derocher and his crew fill black garbage
bags with rocks and throw them out the window. The direction of
the bags tells them where the ground is.
helicopter lifts off, headed north. Within 10 minutes, they spot
more tracks, this time a mother and two plump yearlings. Andersen
fills a syringe and rests the shotgun on his leg.
whose towering height, jet-black hair and full beard give him the
aura of a big black bear, was raised along the lush banks of British
Columbia's Fraser River. Claustrophobic in cities, he heads north,
far north, whenever he craves wilderness.
foot in Svalbard in 1996, Derocher thought he had found paradise.
Having researched wildlife in Canada, he had a longtime dream: 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, the archipelago has been a national refuge.
When Derocher arrived, the population should have fully recovered.
it wasn't long before he knew something was amiss.
just don't appear right," Derocher told colleagues. Why weren't
there more bears? Where were the older ones? It was as if they were
still being hunted. Then he came across some bears with mixed female-male
the first year, it became pretty darned clear that I wasn't working
with an unperturbed population," Derocher says.
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
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.
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.
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 that 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.
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.
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.
of the concerns about Arctic wildlife center on the ability of the
contaminants to suppress immune systems and disrupt sex hormones.
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 less PCBs, according to research
by Hans Jorgen Larsen of the Norwegian School of Veterinary Science.
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.
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.
the last 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
chemicals also might have led to a missing generation of mother
bears. Only 11% of Svalbard bears with cubs were over 15 years old,
compared with 48% in Canada, said Geir Gabrielsen, the Norwegian
Polar Institute's director of ecotoxicology.
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.
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 on Canadian bears. Concentrations were three
times higher in denning mothers who wound up losing their cubs than
in mothers whose cubs survived.
says Svalbard's bears are denning more often than others, closer
to every two years than three years, which is a sign that their
cubs could be dying early, because mothers are supposed to stay
with their young for three years before giving birth again. But
some scientists, including Derocher, are unconvinced without more
evidence because cub survival varies naturally from year to year.
inherent weakness of wildlife toxicology is in proving cause and
effect, says Peter Ross, a Canadian scientist who studies contaminants
in seals and orcas. 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, like they have with PCBs. Experiments with
lab rats, wild animals, captive seals and even humans all show similar
uncertainty is compounded in Svalbard, where due to its remoteness,
scientists don't even have a reliable population estimate or know
how often or why bears die.
Norstrom said that after about 15 years of research, scientists
are finally on the cusp of proving that PCBs are harming Arctic
wildlife. "We're at the threshold, in a lot of ways, with polar
bears," he said.
have only just begun trying to understand newer contaminants that
are showing up near the North Pole, especially brominated flame
retardants called PBDEs, and perfluorinated chemicals, including
some formerly used in Scotchgard.
applied to hard plastic and polyurethane foam, have been detected
in every species tested: fish, seals, polar bears, beluga whales,
pilot whales and birds. Muir said Arctic levels are low but increasing
— doubling every few years — so they will soon catch
up to PCBs.
like PCBs, disrupt thyroid hormones, altering the learning ability
and behavior of newborn mice exposed to low doses in lab experiments.
flame retardants probably cause similar problems in wild animals,
said Cynthia de Wit of Stockholm University's Institute of Applied
Environmental Research. For example, when a bird's brain is altered,
it has impaired hunting skills, she said.
unlike the obvious problems of the past, today's doses of environmental
chemicals cause symptoms that are subtle and difficult to diagnose
contaminants aren't a sledgehammer," De Wit said. "They
might just be a regular hammer."
before 9 p.m., the Polar Institute crew is done for the day, so
the pilot turns the helicopter back toward the town of Longyearbyen,
the northernmost civilization on Earth. To the north, clouds are
closing in on them, threatening a whiteout. But a perfect path of
crystalline skies has opened to the south.
landscape below looks almost voluptuous. Curvaceous, rounded granite
peaks are bathed in soft light, awash in hues of icy blue and frosty
white. The three men are glowing with the satisfaction — and
relief — of knowing they are headed back for a hot dinner
and warm bed before they wake up and head out again. They captured
six bears on a tank of fuel, and all are safe, men and bears. This
is Derocher's last foray into Svalbard before he heads back to his
alma mater, the University of Alberta, to start new bear research
seven years in Svalbard weren't enough to illuminate the ecological
mysteries of this enigmatic place, and other scientists will carry
on the work. The contaminants will continue to haunt the Arctic
— frozen in time, slow to heal — for generations.
peers out the helicopter window and remarks on the clarity of spring's
eternal light. He knows winter will descend soon enough, plunging
Svalbard into darkness again. And somewhere out there, in the dark,
another polar bear will be born.