Radioactivity

Radioactive actual gets into the oceans from accustomed geological processes on the sea floor, but radioactive isotopes from animal nuclear action can add to this. In the Arctic, radioactive actual has been dumped in the Kara Sea to the east of the Barents Sea.
And radioactive actual from nuclear accidents such as the 1986 Chernobyl adversity has accomplished the seas, forth with particles from atmospheric tests of nuclear weapons.


Vast piles
The affirmation that bird debris are bringing radioactivity aground comes from Mark Dowdall and his aggregation at the Norwegian Radiation Protection Authority in Tromsø. They spent two years amid 2000 and 2002 accession soil, frondescence and guano samples from a limited littoral basin alleged Kongsfjord on the Arctic archipelago of Svalbard, about center amid the arctic tip of Norway and the North Pole.



The samples of bird debris were from all-inclusive bags produced by two colonies of seabirds acknowledging kittiwakes, puffins and fulmars. Tests showed the guano independent 10 times the absorption of radioactive isotopes begins at added sites on the island.
The advisers begin almighty top concentrations of the accustomed radioisotopes uranium-238 and radium-226, which adulteration to anatomy added chancy isotopes. But they as well begin top concentrations of the isotope caesium-137, which does not action naturally. Dowdall suspects this is from the fallout of atmospheric nuclear tests agitated out decades ago.
Tests on frondescence growing abreast the guano as well appear top concentrations of radioactive material. "It agency that low levels in the Arctic ambiance don't break low, they become concentrated," he says.


Fish and crustaceans
Dowdall believes the birds eat attenuated angle and crustaceans, and the radioactive actual is again concentrated in their faeces. The added nutrients the debris accommodates animate plants to grow and the plants yield up and apply the radioactive material.
This poses a problem, because plants accomplish up the aggregate of the diet of abounding animals, abnormally that of aboriginal reindeer. "We're talking about a actual accessible environment, and if reindeer eat the [contaminated] vegetation, it's in the aliment chain," says Dowdall.
Environmental advisers are absorbed by the finding. "I don't anticipate humans accept looked at this accurate alleyway before," says Scott Fowler at the International Atomic Energy Authority's Marine Environmental Lab in Monaco.
However, in 1999, pigeons roosting in attenuated barrio on the website of British Nuclear Fuels' Sellafield reprocessing circuitous in Cumbria were begin to accommodate 40 times the European Union's safe absolute of caesium-137.