Unlucky polar bears beset by toxins too

2017-01-06 10:38
This file photo taken in 2007 shows a Polar Bear walking on the frozen tundra on the edge of Hudson Bay, waiting for the Hudson Bay to freeze-over, outside Churchill, Mantioba, Canada. (Paul J. Richards, AFP)

This file photo taken in 2007 shows a Polar Bear walking on the frozen tundra on the edge of Hudson Bay, waiting for the Hudson Bay to freeze-over, outside Churchill, Mantioba, Canada. (Paul J. Richards, AFP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Paris - Polar bears just can't catch a break.

Already struggling to cope with climate change, the giant Arctic carnivores also face a chemical poisoning risk 100 times above levels considered safe for adult bears, according to a study released on Thursday.

For bear cubs feeding on contaminated milk, that risk is 1 000-fold greater, researchers reported in the journal Environmental Toxicology and Chemistry.

"This work is the first attempt to quantify the overall risk of persistent organic pollutants" - known as POPs - "for the Arctic ecosystem", said lead author Sara Villa, a toxicologist at the University of Milano Bicocca in Italy.

For the study, Villa and her team canvassed 40 years of research on the exposure of polar bears, seals and Arctic cod to these deadly compounds.

The data covered bears living between Alaska and the Svalbard Islands above Scandinavia - far less is known about the population in the Russian Arctic.

POPs are easily-spread chemicals that can persist in natural environments for decades, and become more concentrated as they move up the food chain.

By the time they travel, say, from plankton to fish to seals to polar bears, these compounds accumulate into highly toxic doses.

Used in industry and agriculture, some are also found in consumer products such as fabric flame retardants.

In the 1970s, a class of industrial chemicals called PCBs - found to cause cancer and wreak havoc with hormones - were widely banned, but concentrations in Arctic mammals remained high well into the 1990s.

There are traces still today.

But even as PCBs have declined, a new family of pollutants has taken their place, and today pose the greatest chemical threat to polar bears, the study found.

Cubs at risk

"Perfluorooctane sulfonate" - more commonly known as PFOS - "is considered very toxic for mammals," the study notes.

"Their concentrations in polar bears are surprisingly high," a hundred times more than in seals.

At the same time, when bears eat contaminated seals, the toxins increase in concentration 34-fold.

Unlike PCBs, these chemical compounds are still in production and accumulate in protein - muscle - rather than fat.

They are used primarily in water and oil repellents for paper, packaging and fabrics, as well as in certain fire-fighting foams.

For a composite "hazard risk" of 19 different organic chemicals found in polar bear tissue, half the danger came from PFOS.

Bear cubs are especially at risk.

The Canadian government has independently concluded that this class of chemicals constitutes "a danger to the environment," and especially to wildlife.

Even without taking these new threats into account, recent surveys have concluded that the total polar bear population - estimated at about 26 000 - is on track to drop a third by mid-century.

The main threat is the rapid decline in sea ice, which the bears use as floating platforms to hunt seals that can outswim them in open water.

Global warming - which has pushed up Arctic temperatures twice as fast as the global average -- could produce ice-free summers in the Arctic Ocean within a couple of decades, scientists say.

With this additional threat, "it is fundamental to continuously implement the control of new and emerging contaminants," Villa cautioned.

Read more on:    global warming

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.

Inside News24


6 myths about male cancer

It is important to be aware of the most prevalent cancer diseases amongst men in our country.


You won't want to miss...

Who are the highest paid models of 2017?
10 gorgeous plus-sized models who aren't Ashley Graham
5 top leg exercises for men
10 best dressed men of 2017
Traffic Alerts
There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.