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Article Last Updated: 07/12/2006 |
Mercury's
frequent trips spread health dangers
Hard
to hide from: High concentrations have been
found in the Rockies
Mercury
sometimes uses air currents like a passenger on a global TRAX light
rail train
- catching a ride, hopping off, then jumping on again, all over
creation.
This "grasshopper
effect," says U.S. Geological Survey researcher Donald H. Campbell,
means
currents often carry mercury soot far from the coal-burning power
plants and
other pollution sources that produce it.
And this
air-transport system
is so effective that Campbell's team of scientists has found as much
mercury in
remote, high-elevation areas of the Rocky Mountain National Park in
Colorado as
in industrialized mercury hot spots in the Midwest.
"There's a global
pool
of mercury we need to be concerned about," he told Salt Lake City
scientists Tuesday during an informal presentation at the USGS office.
Utahns have been
puzzling for
more than a year over why some of the highest levels of toxic mercury
have been
found in the Great Salt Lake, which is relatively isolated from power
plants
generally blamed for most mercury pollution.
The concern has
grown as
state health and environment officials issued the state's first-ever
advisories
against eating fish because of too-high mercury and the nation's
first-ever
warnings against eating two duck species with excessive mercury.
David Naftz, a
Utah-based
Geological Survey geochemist, said his colleague's findings offer
perspective
on the role air currents might play in delivering mercury into the
local
environment. But he also noted that, while there is good data about
mercury
falling in the Colorado national park, there is virtually none showing
how
currents deposit mercury here.
"It points to a big
data
gap here in Utah," he said. "It seems like a big hole we need to try
to address."
Scientists and
environmentalists have speculated that gold ore "roasters" in Nevada
pump tons of mercury into the air every year, which later drifts into
Utah. But
coal-fired power plants in China and other sources around the world
might also
be playing a role.
State environmental
officials
have requested a grant of more than $100,000 from the U.S.
Environmental
Protection Agency to study the issue. But they have put off air
monitoring for
now.
The grasshopper
effect allows
mercury to be washed from the skies onto the ground, and because
mercury
readily resumes its vapor form when it's warmed, it can go airborne
again and
again. Neither sulfur nor nitrogen has this hopping habit, making
mercury's behavior
a new puzzle for scientists.
Campbell showed one
map that
revealed mercury in the snow at Colorado's Buffalo Pass that was 7.6
micrograms
per cubic meter - comparable with sites in Wisconsin, where there is a
statewide fish advisory because of mercury.
Mercury sometimes
takes a
toxic form in the environment that builds up in the food chain. It also
builds
up in people who eat too much mercury-tainted fish.
People with high
levels of
mercury can suffer a variety of health problems, including neurological
problems. Unborn children and young children are considered especially
vulnerable. Campbell also has studied acid rain and has watched how
increasing
amounts of nitrogen wind up in remote parts of the Rockies and disrupt
plant
and animal systems that are not used to being so heavily fertilized.
Logan, in Utah's
Cache
County, is one such hot spot. Scientists are interested in how this
excess
nitrogen might contribute to the air pollution problems the northern
Utah
university town has in the winter.
fahys@sltrib.com