Bear Facts
Pollution
How can animals in the Arctic be contaminated by pollutants entering the air and water elsewhere in the world? It happens because everything is connected to everything else. Dust from storms in the Sahara Desert, soot from the cooking fires of India and Africa, and chemical fumes from third-world industries rise in the sky and travel around the world to settle onto the snow and ice of the Arctic.
Likewise, contaminants entering rivers and seas from agricultural run-off, untreated sewage, and chemical-laden discharge from ships and factories become entrained in globe-girdling ocean streams to enter environments far from their source.
As wind and water have always affected everything, the presence of so-called pollutants in the Arctic is nothing new. But the addition of modern synthetic chemicals is new. The best studied example is the synthetic organic chemical compound known as PCB, short for Polychlorinated Biphenyl. Used in hundreds of industrial and commercial applications throughout the world, the manufacture of PCBs was banned when it was learned that they persist in the environment and are injurious to wildlife. Entering the oceans, trace amounts of PCBs eventually make their way to the Arctic, are gradually concentrated as they rise up the food chain, and are ingested by polar bears through their prey base of seals.
Studies indicate that high levels of PCBs in the blubber of polar bears appear to hamper their immune systems. This can lead to greater susceptibility to parasites and disease. High PCB levels in bears have also been linked to reproduction failure and malformed organs.
Studies show that all polar bears carry significant pollution loads, although the exact levels at which such pollutants lead to biological problems is unknown. In addition, multiple pollutants sometimes have synergistic effects.
A number of countries over the past years have recognized the dangers of free-ranging chemicals and have significantly reduced their use of these pollutants. Recently, the major industrial nations signed an international treaty, the “Stockholm Convention on Persistent Organic Pollutants" (or "POPs") which calls for increased efforts to reduce, contain, and eliminate POPs. But the effects of current pollutants in the environment may be felt for decades.
Likewise, contaminants entering rivers and seas from agricultural run-off, untreated sewage, and chemical-laden discharge from ships and factories become entrained in globe-girdling ocean streams to enter environments far from their source.
As wind and water have always affected everything, the presence of so-called pollutants in the Arctic is nothing new. But the addition of modern synthetic chemicals is new. The best studied example is the synthetic organic chemical compound known as PCB, short for Polychlorinated Biphenyl. Used in hundreds of industrial and commercial applications throughout the world, the manufacture of PCBs was banned when it was learned that they persist in the environment and are injurious to wildlife. Entering the oceans, trace amounts of PCBs eventually make their way to the Arctic, are gradually concentrated as they rise up the food chain, and are ingested by polar bears through their prey base of seals.
Studies indicate that high levels of PCBs in the blubber of polar bears appear to hamper their immune systems. This can lead to greater susceptibility to parasites and disease. High PCB levels in bears have also been linked to reproduction failure and malformed organs.
Studies show that all polar bears carry significant pollution loads, although the exact levels at which such pollutants lead to biological problems is unknown. In addition, multiple pollutants sometimes have synergistic effects.
A number of countries over the past years have recognized the dangers of free-ranging chemicals and have significantly reduced their use of these pollutants. Recently, the major industrial nations signed an international treaty, the “Stockholm Convention on Persistent Organic Pollutants" (or "POPs") which calls for increased efforts to reduce, contain, and eliminate POPs. But the effects of current pollutants in the environment may be felt for decades.
Pollution - Related Topics
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