Toxins threaten polar bears – 01/23/2006

  • November 23, 2013 at 1:34 am #1128

    from rocky

    Toxins threaten polar bears
    January 17, 2006

    LOS ANGELES: Already imperiled by melting ice and a brew of toxic
    chemicals, polar bears throughout the Arctic, particularly in remote
    dens near the North Pole, face an additional threat as flame
    retardants originating largely in the US are building up in their
    bodies, an international team of wildlife scientists says.

    The flame retardants are one of the newest additions to hundreds of
    industrial compounds and pesticides carried to the Arctic by winds and
    ocean currents. Accumulating in the fatty tissues of animals, many
    chemicals grow more concentrated as larger creatures eat smaller ones.

    In urban areas, particularly in North America, researchers have shown
    that levels of flame retardants called polybrominated diphenyls, or
    PBDEs, are growing at a rapid pace in people and wildlife. Although
    they have been found in much lower concentrations in the Arctic,
    scientists say their toxic legacy will persist there for years because
    they are slow to break down, particularly in cold climates.

    In polar bears, the effects are unknown. But in tests on laboratory
    animals, PBDEs disrupted thyroid and sex hormones and damaged
    developing brains, impairing motor skills and mental abilities,
    including memory and learning.

    Scientists say that other industrial chemicals with properties similar
    to PBDEs are already weakening the bears’ immune systems, altering
    their bone structure and skewing their sex hormones.

    Derek Muir from Canada’s National Water Research Institute, who led
    the new research, said the geographical patterns in contamination
    suggest that the east coast of North America and north-western Europe
    are the primary sources of the flame retardants.

    Los Angeles Times

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