- New research suggests that there are
no places on Earth that are free of pollution, a Canadian scientific team
says.
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- Scientists from the University of Alberta
studied snow in some of Canada's most remote regions - and found high levels
of industrial pollutants and agricultural pesticides.
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- The team, writing in the journal Nature,
say the pollutants were transported from developed areas and deposited
on the ground as snow or rain when the air cooled.
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- And they say that, since it is likely
the same process is going on all over the world, food and water supplies
need to be monitored in parts of the globe previously thought to be free
of pollution.
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- The chemicals concerned, organochlorides,
are a type that tends to build up in the food chain, so although they might
be harmless to a fish, they could be more toxic to humans who eat the fish.
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- David Schindler, from Alberta University,
says his team has shown for the first time the extent of organochloride
pollution in mountain regions.
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- Analysis of snow samples from mountains
in western Canada showed that organochloride accumulation increased drastically
between altitudes of 770m and 3,100m.
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- Writing in Nature the researchers said:
"There is reason to believe that levels of organochlorides in snow
would continue to increase at higher elevations.
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- "Cities like Denver and Mexico City
derive their water supply from snow melted on mountains over 3,000m high.
They are also much closer to industrial and agricultural sources of contaminants."
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- The Alberta team says that there is likely
to be a "more pronounced accumulation of toxic compounds" in
such areas than in the snows of their study area.
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