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Los Angeles Times
Copyright 2002 Los Angeles Times
Thursday, June 6, 2002
National Desk; National
THE NATION Dentists Biggest Mercury Polluters, New Study Finds Health: The
metal is widely used in fillings and ends up in the nation's waste water.
ELIZABETH SHOGREN
TIMES STAFF WRITER
WASHINGTON -- WASHINGTON -- Coal-fired power plants are notorious for being
the biggest source of mercury pollution in the air. But now, new attention is
being directed at another, much less known source of mercury contamination in
water--dentists.
A new report shows that dentists are the largest single source of mercury
pollution in waste water funneled into the nation's treatment plants.
Mercury is a potent toxin that can damage the human brain, spinal cord, kidney
and liver, and is especially dangerous for unborn children.
While many other sources of mercury pollution have drastically cut their use of
the heavy metal, dentists continue to use it widely in fillings.
"Pretty much all the mercury they're using gets released into the environment.
Why aren't they doing more to reduce that use?" said Michael Bender, director of
the Mercury Policy Project, a foundation-funded group that was one of the
authors of the study.
Power plants emit mercury into the air and it falls into streams and rivers.
Many dentists flush it down their drains and it goes directly into waste-water
treatment plants, which do not effectively filter it from the water.
In a statement responding to the report, the American Dental Assn. said it was
aware that some particles from fillings end up in waste water, and it urges
dentists to follow proper procedures for handling and recycling the composite
used for fillings, which they refer to as "amalgam." But the association argued
that the mercury from their fillings remains in a form that is not harmful to
humans.
"However, a 1996 study found that when amalgam particles were subjected to
simulated waste-water treatment processes, no soluble mercury was detected, even
at a concentration of 1 part per billion," according to the statement.
The group stressed that it was currently implementing a new plan to address the
problem.
The new report's authors said that dentists, through voluntary or mandatory
measures, should trap their waste mercury before it flows into plumbing fixtures
that have been contaminated with mercury for years.
The report referred to a 2001 study by the Assn. of Metropolitan Sewerage
Agencies that evaluated seven major municipal waste-water treatment plants and
determined that dental uses were "by far" the greatest contributors to the
mercury reaching their facilities. They were responsible for 40% of the load,
three times more than the next largest contributor.
Several other countries regulate releases of dental mercury. In Canada, a new
standard requires dentists to trap the pieces of filling before they go down the
drain. The goal is to reduce releases by 95% by 2005.
In May, the New Hampshire Legislature became the first in the nation to pass
legislation governing disposal methods for dental mercury.
The California Assembly considered a measure to phase out the use of mercury in
fillings but did not adopt it.
The report suggests that mercury in dentistry has become the exception while
other major users of mercury have changed their practices.
In 1985 dental facilities used 3% of all the mercury used nationwide. Last year,
although dentists used less mercury, their use accounted for 20% of all uses.
Only two other industries--wiring devices and switches and chloralkali-- used
more.
Gina Solomon, a physician who focuses on the health effects of mercury for the
Natural Resources Defense Council, said that there was still controversy about
whether the fillings put dental patients at risk. And she stressed that those
who have such fillings should not get them removed, because taking them out
heightens the chance of exposure.
However, she said the science is clear that the mercury that goes down the drain
can end up in the food chain.
"There is scientific consensus that mercury that ends up in the waste water and
water bodies will accumulate in the fish and pose a direct human health problem
to people who eat the fish; that is uncontroversial and is something that can be
fixed," Solomon said.