Seabirds - conspicuous polluters of newly polished cars in seaside towns - are also the culprits behind the pollution of the Arctic, according to Canadian scientists.
They report in Science today that most of the human-made contaminants found in the pristine high Arctic were dumped there in the traditional way by breeding birds called northern fulmars.
Jules Blais of the University of Ottawa and colleagues measured the levels of DDT, mercury, polychlorinated biphenyl and other organic pollutants found in North Devon Island, where northern fulmars migrate to nest each summer.
Where there were no seabirds, they found low levels of toxins. In the sediments of ponds and lakes nearer the nests, they found 60 times the concentrations of pollutants, almost certainly delivered from human settlements.
"These contaminants have been washed into the ocean, where we generally assumed they were no longer affecting terrestrial ecosystems," Professor Blais said. "Our study shows that seabirds, which feed in the ocean but then come back to land, are returning not only with food for their young, but contaminants as well. The contaminants ... are released on land."
The "guano factor" means that even remote communities are at risk. "Some chemicals will build up in the food webs that comprise northern traditional diets," said Linda Kimpe, also of the University of Ottawa. "As a result some of our northern Canadian populations are among the most mercury and PCB-exposed people on the globe."
They report in Science today that most of the human-made contaminants found in the pristine high Arctic were dumped there in the traditional way by breeding birds called northern fulmars.
Jules Blais of the University of Ottawa and colleagues measured the levels of DDT, mercury, polychlorinated biphenyl and other organic pollutants found in North Devon Island, where northern fulmars migrate to nest each summer.
Where there were no seabirds, they found low levels of toxins. In the sediments of ponds and lakes nearer the nests, they found 60 times the concentrations of pollutants, almost certainly delivered from human settlements.
"These contaminants have been washed into the ocean, where we generally assumed they were no longer affecting terrestrial ecosystems," Professor Blais said. "Our study shows that seabirds, which feed in the ocean but then come back to land, are returning not only with food for their young, but contaminants as well. The contaminants ... are released on land."
The "guano factor" means that even remote communities are at risk. "Some chemicals will build up in the food webs that comprise northern traditional diets," said Linda Kimpe, also of the University of Ottawa. "As a result some of our northern Canadian populations are among the most mercury and PCB-exposed people on the globe."
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