A Congressional oversight panel is pressing the Environmental Protection Agency (EPA) to require that all dentists in the U.S. install amalgam separators in their offices.
In a May 26 hearing, a subcommittee of the House of Representatives' Committee on Oversight and Government Reform demanded to know why the EPA exempts dentists from regulations that govern mercury emissions in other industries.
"There is no question that mercury should not be in the water supply and we should do everything we can to get it out of there," Rep. Dan Burton (R-IN) said. "And the biggest contaminators are dentists who are flushing this stuff down the drain, so we need to have these separators. That's important. I'm pretty upset about this."
The EPA and the National Association of Clean Water Agencies signed a memorandum of understanding (MOU) with the ADA on December 29, 2008, in which the ADA agreed to urge its members to install the separators, begin tracking how many practices have installed them, and set goals for increasing that number. In exchange, the EPA exempted dentists from wastewater rules.
A 2009 ADA survey found that 40% to 51% of dentists use amalgam separators, but that dropped to 28% to 36% in states where they are not required by law. The response rate to the survey, done by mail and Internet, was so low that the ADA admitted it was uncertain about the accuracy of these numbers.
Where does it go?
Testimony submitted by SolmeteX, an amalgam separator company, placed the percentage of dental offices using separators at about 32%. According to SolmeteX, sales of separators have surged in the 11 states that require them, but not increased in states that don't require them since the MOU was signed.
— U.S. Rep. Dan Burton
"My staff assessed progress made under the MOU," said Rep. Dennis Kucinich (D-OH), chairman of the committee's Domestic Policy Subcommittee, in the hearing. "What we have found is that every milestone established by it has been missed in the nearly one and one-half years since it was signed."
Speaking on behalf of the ADA, attorney William J. Walsh argued that the government still shouldn't require dentists to install separators because enough of them will do it on their own.
Walsh argued that very little mercury from dental offices pollutes the environment. "Even without separators, dentists capture in their offices approximately 78% of the waste amalgam, with almost all of the remaining 22% captured by water treatment plans before the wastewater is discharged to surface water," he said. "In other words, approximately 99% of the amalgam is captured in the office or by the sewage treatment plant prior to discharge in rivers, streams, or lakes."
He argued that mandating separators nationwide would not be worth the expense of enforcement, since 0.4% of mercury in surface waters comes from dentistry and dentists are using less and less amalgam.
Nancy Stoner, an EPA deputy administrator, focused on the problem of mercury emitted into the air, which can happen directly from preparation of amalgam in dental offices (0.6 tons), when dental amalgam in sewage sludge is incinerated (0.6 tons), or when corpses with amalgam restorations are cremated (0.3 tons). Altogether she estimated that 1.5% of the 103 tons of mercury emitted annually into the U.S. air comes from dentistry.
Witnesses at the hearing gave estimates ranging from $500 to $2,000 of the cost of buying and installing an amalgam separator. Separators can catch 95% of the amalgam that goes down the drains in dental offices, according to the EPA.
But EPA scientist Alexis Cain, testifying as a private citizen, said he thought the agency had underestimated the emissions from crematoriums. By analyzing the amount of amalgam in each corpse, the emissions could be as much as 2 tons per year, instead of the 0.3 tons cited by Stoner, he said.
Passionate speeches
One reason the air pollution is a problem is that the mercury ends up in water, where microorganisms can convert it to methylmercury, which accumulates in fish. When consumed by pregnant women, this form of mercury can damage the nervous systems of fetuses.
While sewage overflow, septic systems, sludge in landfill or spread on land, and other disposal of sewage grit and fines may also contribute to mercury pollution, Stoner said they are a lesser concern because heat is not applied to the amalgam, so mercury is less likely to be released.
Both Burton and Rep. Diane Watson (D-CA), influenced by personal experiences, gave impassioned statements about the problems of mercury pollution. Watson said her health had improved after she had amalgam fillings removed in Mexico, after her own dentist refused to remove them. She has repeatedly introduced legislation requiring dentists to inform patients that amalgam contains mercury.
Burton, who blames his grandchild's autism on mercury as an ingredient in a vaccination, said nothing containing mercury should be used in a human body.
The hearing ended with subcommittee members asking the EPA to respond in writing to questions about how the agency would prepare better estimates of the problem of mercury from cremation and incineration.
"As part of our 2010 effluent guidelines planning process, EPA intends to re-evaluate whether a rulemaking is appropriate," Stoner said. "EPA will be issuing its 2010 Program Plan late this calendar year and will specifically address this issue."
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