Clean Water Advocacy - Newsroom - AMSA in the News
At Issue: Mouth Mercury
Monday, May 31, 2004 11:39 AM
The Capital Times
By Anita Weier
May 31, 2004Write a letter to the editor.
Mercury in tooth fillings are adding to the problem of mercury in the
environment. (File photo)
Related articlesRob Zaleski: Mercury threat not media ploy; it's serious and
it's hurting kids
Chances are that you are walking around with mercury in your teeth.
Mercury is a toxic substance that can damage the nervous system. And though the
stable form of mercury in fillings is not regarded as a health problem, the
excess amalgam in waste from dental offices worries sewer district officials.
"The stuff that sloughs off your teeth does not accumulate in the body. It goes
into the urine. It is not a danger to your health," said Jon Schellpfeffer,
chief engineer and director of the Madison Metropolitan Sewerage District.
"Mercury leaves the teeth and ends up in the waste. It is in such small
quantities, but we can detect it. "
Recently, two people who work at the Madison sewer district put a measured
amount of water in their mouths and swished it around for a minute. They ended
up with concentrations of mercury that were from two to four times greater than
the concentrations in the raw waste, he said.
"They had not been to the dentist recently, but they had amalgam fillings,"
Schellpfeffer said.
Dane County recycling manager John Reindl, who has done extensive mercury
research, noted that the very tiny amount excreted in urine and feces adds up,
when 400,000 county residents use the toilet several times a day. Mercury from
fillings also can enter the waste stream from dental offices, when patients spit
out that little piece of mercury filling after rinsing and it goes down the
drain, or when the dentist takes out an old filling and puts in a new, Reindl
said.
"Dental mercury doesn't decompose very rapidly. It will go out to sewage sludge
in particles and sludge is typically spread on agricultural land," he added.
The handling of dental amalgam filling is getting a lot more attention lately,
courtesy of U. S. Rep. Tammy Baldwin, D-Madison. She has introduced a bill that
would limit mercury in everyday life by using grants to encourage recycling by
schools and other mercury users, banning the sale of mercury thermometers, and
requiring amalgam separating devices in every dental office.
The Wisconsin Dental Association opposes her plan.
"Our association has been very pro-active about mercury in wastewater," said Dr.
Dennis Engel, a Mequon dentist who is president of the association.
"In 2002 we came out with a brochure on best management practices on how each
dentist should deal with dental waste. Last year we came out with a video that
was distributed to every dentist in the state. If those practices are used, we
could remove 80 percent of all types of dental waste. "
The dental association worked with the state Department of Natural Resources in
regard to new permitting requirements for mercury in wastewater and is working
with sewer districts to meet the new requirements.
But the association opposes mandated dental amalgam separators in every office,
saying they are not necessary if the best management practices are used.
Those practices include collecting any extra filling that is carved off a tooth
restoration or removed from a patient's mouth or in extracted teeth. That extra
amount is kept in a sealed container. Chairside traps and filters in vacuum
systems also collect a good percentage of the amalgam, Engel said.
"We segregate that. We do not throw it in the trash where it would be
incinerated. We collect it and give to it licensed recyclers," he said.
"We met with Congresswoman Baldwin and said we would like to work with her in
developing recycling centers to make it easier for dentists to recycle dental
waste, and in creating some grant opportunities. We agreed to disagree on the
mandate. There is no scientific evidence that putting in a separators would
improve water quality at all. The sewer districts also do a great job of
eliminating the mercury at their end. "
The Wisconsin Dental Association and the American Dental Association also stress
that dentistry provides less than 1 percent of all mercury released into the
environment from human activity.
Wait a minute, says Baldwin, who does not plan to drop the equipment requirement
from her legislation.
That 1 percent includes air emissions as well as other wastes, she said, and
though coal-burning power plants and chlorine plants send the greatest
percentage of mercury into the air, mercury used in everyday products
contributes a hefty amount in wastewater and air.
"Dentists are the third largest user of mercury in products in the United
States, consuming over 22 percent of the 220 metric tons used in 2001," Baldwin
said.
"The WDA wanted to tell me about some of the very positive steps the association
is taking on this issue. However, this legislation is being proposed at the
national level and not all state dental associations have been as pro-active. "
Her bill is a national effort to reduce the presence of mercury in water and
landfills, which is why the dental provision is included, Baldwin said.
Dentists would have plenty of opportunity to comment on an EPA rule that would
implement the provision, she said.
Baldwin said she would be glad to work with the dental association to improve
recycling efforts.
"Right now, depending on where you have a dentistry practice, resources for
recycling amalgam vary greatly," she said. "They prefer not to have a mandate,
but my goal is to have a comprehensive piece of legislation that deals with how
mercury gets into waterways and landfills. We hear a lot about legislation aimed
at emissions from smokestacks. But there hasn't been a sufficient review of all
the ways mercury gets into our environment. "
A recent study by the Association of Metropolitan Sewer Districts at seven major
municipal wastewater treatment plans found that dental use was by far the
greatest contributor to the mercury load, accounting for 40 percent, according
to Baldwin.
Meanwhile, the Milwaukee Metropolitan Sewerage District has required that
dentists within the district install amalgam separators by 2008.
"In exchange for that, the district decided to work with us and say there would
be no testing of effluent coming from our dental offices," Engel said. "The only
requirement will be to have someone come in and see the separator installed and
examine a manifest from the licensed recycler. "
Randy Case, community mercury reduction coordinator for the DNR, said that
amalgam forms a significant part of mercury releases into sanitary sewer
systems, "probably the single largest release. "
The Wisconsin Dental Association has been very cooperative in working to reduce
mercury discharges, he said. "We have a partnership in promoting best practices
and installing separators," Case said.
A relatively new DNR rule, NR106, requires municipalities to implement community
pollution reduction programs if discharges exceed water quality material.
"So municipalities are collecting effluent results for mercury they can compare
with discharge standards. We think most will exceed, and then they will need to
minimize mercury," Case said.
That means less mercury will have to be used or it will have to be recycled.
"The limit that needs to be met by industrial and municipal sewer systems is 1.
3 nanograms per liter. Municipal systems are typically 5 nanograms per liter,
which is low but not low enough to meet the standard," Case said. "They don't
have to implement it unless data shows they should. The two-year collection
period will end in late 2005 for most. We will start receiving proposed plans in
late 2005 or early 2006. Implementation would probably be over the next five to
10 years. "
Both the Madison and Milwaukee sewer districts have done good pilot work,
according to Case.
Schellpfeffer said that about 1 to 2 ounces of mercury comes to the Madison
Metropolitan Sewerage District plant in 330 million pounds (40 million gallons)
of wastewater per day.
"It is in the parts per trillion range, so testing is difficult. Mercury is
certainly something everybody is concerned about, even in these low
concentrations. We are trying to reduce sources whenever we can," Schellpfeffer
said.
"We produce roughly 110,000 gallons of biosolids a day, so the 1 to 2 ounces
will be in that quantity of biosolids. The wastewater comes in and we treat it.
We end up with two side streams. For every 1,000 gallons that come in, 3 gallons
go out in biosolids and 997 go out as clean water. The biosolids are
concentrated and stabilized in a liquid form. We recycle our biosolids to
farmland. The sludge is injected below the surface. "
Mercury entering the system comes primarily from humans, he said, in dental
amalgam, red and yellow food dyes, and old mercury thermometers. For the most
part, it comes from homes, though dental offices are another significant source,
he said.
Newer dental offices are putting in amalgam separators, according to
Schellpfeffer. The Madison sewer district is holding off on an ordinance
requiring them, waiting to find out if the state will regulate more broadly.
"We suspect that will happen," Schellpfeffer said. "We are apprising dentists
that this is something that is coming and they should be aware. "
However, the Madison sewer district is well below limits. "Mercury in our
biosolids is 1. 9 milligrams per kilogram of solids. The EPA has a limit of 17
for exceptional quality of biosolids. They don't regulate until it is 57
milligrams per kilogram," he said.
Industries have cleaned up their use of mercury and other heavy metals in the
last 20 years, according to Schellpfeffer. "The main areas we are looking at,
the bulk is from domestic wastewater. The best way to eliminate that is some
kind of product substitution somewhere up the consumption line. "
Ultimately the solution is to stop using mercury in products, Reindl said.
"We have alternatives for most products. We don't have great alternatives for
fluorescent lamps and dental fillings. There are ceramic and gold fillings but
some don't think they are very durable. They are also very expensive, and some
dental insurance won't cover anything but mercury," he said.
Some nations want to ban mercury in all products, and some want to bury it
forever, Reindl said.
"In the United States, we have had legislation to set up a commission to retire
mercury," he said. "I suspect we will see a commission formed in the next five
years. "
E-mail: aweier@madison. com
Published: 6:41 AM 5/31/04
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