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   Whales reveal extent of ocean pollution

info Coordination marée noire
samedi 26 juin 2010
statut de l'article : public
citations de l'article provenant de : The Australian


AMERICAN scientists have discovered stunningly high levels of toxic heavy metals in whales.

The levels of cadmium, aluminium, chromium, lead, silver, mercury and titanium together are the highest found in marine mammals, the scientists say, warning the health of both ocean life and the people who consume seafood could be at risk.

Analysis of cells from the sperm whales showed pollution was reaching the farthest corners of the oceans, from deep in the polar region to "the middle of nowhere" in the equatorial regions, according to biologist Roger Payne, founder and president of Ocean Alliance, which conducted the research.

"The entire ocean life is just loaded with a series of contaminants, most of which have been released by human beings," Mr Payne said in an interview on the sidelines of the International Whaling Commission’s annual meeting. "These contaminants, I think, are threatening the human food supply. They certainly are threatening the whales and the other animals that live in the ocean." Ultimately, he said, they could contaminate fish that were a primary source of animal protein for one billion people. "You could make a fairly tight argument to say that it is the single greatest health threat that has ever faced the human species. I suspect this will shorten lives, if it turns out that this is what’s going on," he said.

US whaling commissioner Monica Medina informed the 88 member nations of the whaling commission of the report and urged the commission to conduct further research.

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By August 2005 it had collected pencil-eraser sized samples from 955 whales using a dart gun that barely made the animal flinch.

The samples were sent for analysis to marine toxicologist John Wise at the University of Southern Maine. DNA was compared to ensure the animals were not tested more than once.

The original objective of the voyage was to measure chemicals known as persistent organic pollutants, and the study of metals was an afterthought. The researchers were stunned with the results. Though it was impossible to know where the whales had been, Mr Payne said the contamination was embedded in blubber formed in the frigid polar regions, indicating the animals had ingested the metals far from where they were emitted. "When you’re working with a synthetic chemical which never existed in nature before and you find it in a whale which came from the Arctic or Antarctic, it tells you that was made by people and it got into the whale," he said.

How that happened is unclear, but the contaminants most likely were carried by wind or currents.

"The biggest surprise was chromium," Mr Payne said. "

Chromium, a corrosion-resistant material, is used in stainless steel, paints, dyes and the tanning of leather, and can cause lung cancer in people who work in industries where it is commonly used. Mr Wise found the concentration of chromium found in whales was several times higher than the level required to kill healthy cells in a Petri dish.

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