From May 16, 2006
Agricultural
Chemicals Show up in National Park Snow
(Beyond Pesticides, May 16, 2006)
(AP) Scientists have found tiny amounts of agricultural pesticides
in the otherwise pristine winter snow at Mount Rainier and other Western
national parks.
Although the pesticide residue includes some products banned in the
United States, researchers say there is no immediate risk for humans
-- even if they lick the snow. They are still studying the consequences
for
plants, fish and wildlife in the park.
"We thought these areas were pristine, and they're not," Barbara
Samora, Mount Rainier National Park biologist, told The News Tribune
of Tacoma.
Researchers
also found pesticides in winter snow at three national parks in California,
Colorado and Montana. They said the results mostly relate to regional
pesticide use, but they did not rule out the influence of
pollution from other parts of the world.
The pesticide
analysis was based on seasonal snowfall samples collected three years
ago. On Mount Rainier, a team of researchers climbed to Alta Vista,
a viewpoint 5,676 feet above sea level, between Paradise and Camp Muir,
and collected snow samples. Two such treks took place in March 2003.
Snow samples from all the parks showed tiny concentrations of pesticides,
measured in fractions of nanograms. A nanogram equals 1 billionth of
a gram.
"These may well be the cleanest snows anywhere in the U.S., so
the exposure we receive in urban areas is probably higher," said
Dan Jaffe, a University of Washington atmospheric chemist who read the
report.
The lead scientist,
Kim Hageman, an Oregon State University chemist, analyzed snow samples
from seven parks, including three in Alaska. She tested for 47 organic
compounds. Of those, eight stood out, including
four that are banned but persist in the environment.
To identify the source of the contaminants, Hageman compared data on agricultural activity within a radius of about 93 miles of each of the parks. She found the highest concentrations of pesticides in snow from parks near farmlands.
"Clearly,
regional U.S. and Canadian agricultural practices, both past and present,
play a significant role in contributing to the accumulation of pesticides
in the seasonal snowpack," Hageman wrote.
Because there's no farmland near Alaskan parks, scientists concluded
that contamination in snow there originates elsewhere. Hageman detected
the highest concentrations of pesticides in snow from Sequoia National
Park in California, near the Central Valley, which is largely agricultural.
Mount Rainier is affected by both regional and long-range atmospheric
transport of chemical contaminants, Hageman said. "The more cropland,
the more concentration in a nearby national park," she said.
Bridget Moran, a state Department of Agriculture environmental toxicologist,
read Hageman's paper and downplayed the regional influence. "Mount
Rainier tracks closer to background levels in Alaska than it does to
the other national parks," she said.
Besides Hageman, four other scientists contributed to the report, which
appeared in a recent Web edition of Environmental Science & Technology,
a scientific journal.