Open wide for mercury waste rules

Photo by DeaPeaJay. Some rights reserved.

Dental amalgam is a filling material used in restoring teeth that is usually made of up to 50% mercury. Use of amalgam is in decline as better substitutes become available, but each time a dentist replaces and disposes of an old mercury filing, that mercury then has a chance to make it into the environment.

Because disposal of amalgams accounts for 3.7 tons of mercury discharged each year – that’s approximately 50 percent of all mercury discharges – the EPA is planning to move forward with rulemaking to reduce mercury waste from dental offices. Yesterday, the EPA announced that it hopes to propose a rule next year that will require dental offices to use amalgam separators to capture mercury from old filings, which can then be recycled and reused.

Currently many dental offices will simply flush old dental amalgams into chair-side drains, where the mercury can enter wastewater systems, with some eventually – and inevitably – ending up in rivers and lakes. Once mercury has been deposited into the environment, certain microorganisms can change elemental mercury into methylmercury, a highly toxic organic compound. Fish and shellfish easily accumulate and concentrate mercury in their bodies, making consumption of these fish dangerous to humans. Methylmercury can damage children’s developing brains and nervous systems even before they are born.

Some dental offices already take measures to separate out mercury from the effluent discharged to waste treatment plants. In 2008, the EPA’s Office of Water and the American Dental Association (ADA) signed a Memoranda of Understanding (MOU), intended to have dental offices voluntarily install amalgam separators and recycle the collected amalgam waste. However, the EPA’s decision to pursue rulemaking at this time may have come from dissatisfaction with this voluntary approach. According to the Environment News Service, the Dennis Kucinich-chaired House Domestic Policy Subcommittee found that none of the Memorandum’s commitments, milestones and goals had been satisfactorily fulfilled at the time of a May 2010 hearing entitled “Assessing EPA’s Efforts to Measure and Reduce Mercury Pollution from Dentist Offices.”

Of course, ADA representative William Walsh argued at the hearing that dentists need no further regulation. Walsh claimed that “even without separators, dentists capture in their offices approximately 78 percent of the waste amalgam,” and lauded the ADA’s continually updated “best management practices” for handling waste amalgam. Sorry, Walsh, but the EPA’s in motion, and the agency intends to continue outreach efforts under the MOU during the rulemaking process.

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