EPA Proposes Rule to Curb Dentist Mercury Use

Studies show about half the mercury that enters Publicly Owned Treatment Works (POTWs) comes from dental offices.

Amalgam is a mixture of mercury and other metals that dentists use to fill cavities. Mercury is discharged when dentists remove old fillings or remove excess amalgam when placing a new filling.

Mercury from amalgam can make its way into the environment in a number of ways, including through discharge to water bodies. Contact with some microorganisms can help create methylmercury, a highly toxic form of mercury that builds up in fish, shellfish and fish-eating animals. Fish and shellfish are the main sources of human exposure to methylmercury.

1 billion mercury fillings each year


Dental amalgam is a mixture of mercury, silver, tin and copper. Mercury, which makes up about 50 percent of the compound, is necessary to bind the metals together to provide a strong, hard, durable filling.

It is estimated that more than 1 billion amalgam fillings are placed annually.

You can see where the "dust" from that could accumulate in waste water.

The Doctor Oz show did a segment on this. (Both experts on the panel said "we need more research," but both experts on the panel are dentists who have chosen not to use mercury in fillings for the past ~ 20 years. Hmm.)

EPA's proposed rule


EPA says that compliance with its newly proposed rule would cut metal discharge to POTWs, half of it from mercury, by at least 8.8 tons a year. The rule would require all affected dentists to control mercury discharges to POTWs.

Specifically, it would require dentists to cut their dental amalgam discharges to a level achievable through the use of the best available technology (amalgam separators); and the use of other Best Management Practices.

The proposed rule would allow dentists to demonstrate compliance by installing, operating and maintaining amalgam separators. It would declare dental practices whose existing separators do not remove the percentage of amalgam in the proposed requirements as meeting the proposed requirements for the life of the existing separator. Finally, it would limit dental dischargers' reporting requirements to annual certification and recordkeeping in lieu of wastewater monitoring.

For the record, the use of amalgam separators is already named a Best Practice by the American Dental Association, and as such, dentists who keep things current are already moving to that practice.

The agency will accept public comments on the proposal for 60 days following publication in the Federal Register. A public hearing is also scheduled for November 10 at 1 p.m. in the William J. Clinton East Building, Room 1153. The agency expects to finalize the rule in September 2015.

Visit the EPA web site for more details.

(If you'll forgive me, I did not have the heart to look for pictures for this article!)
Kathleen HurleyEPA, dentist, mercury, rule