The Largest Source of Wastewater Mercury Pollution: Dentists

dental mercury pollution photo

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We all know coal-fired power plants are to blame for a lot of the mercury swimming through our waters. But they're not the worst, according to the Mercury Policy Project. Do you know what is? The dental industry. Yep, those silver amalgam fillings are actually composed primarily of mercury, not silver, and the shavings from new fillings and the removal of old fillings—whether when the filling breaks or when teeth are removed whole—help to make America's dentists, collectively, the single largest source of mercury pollution to wastewater.

While the EPA has recognized some public concerns over mercury from dental amalgam, regulation up until now has rested largely on voluntary pollution reduction measures, which the Mercury Policy Project says have barely any effect due to low compliance. The group, which testified before Congress last week on this issue, also charges that the American Dental Association has misled the EPA and the public, saying both that dentists have been voluntarily controlling their mercury pollution and that the metal doesn't end up in the fish that people eat.

Michael Bender, director of the Mercury Policy Project (MPP). "Dentists are the largest polluter of mercury to wastewater. Yet ADA ignores the latest science from the U.S. Navy and others, and pretends that dental mercury doesn't end up in fish."

The EPA agrees: "When amalgam enters water, certain microorganisms can change it into methylmercury, a highly toxic form that builds up in fish, shellfish and animals that eat fish. Fish and shellfish are the main sources of methylmercury exposure to humans.

MPP says that a 2008 EPA agreement with the ADA (which came—huge surprise—during the final days of the Bush administration) was signed based on an assumption that voluntary measures were effectively reducing pollution.

The group writes in a press release about the Congressional hearing, "Evidence of the failure of voluntary programs was extensively documented by a 2008 Domestic Policy Subcommittee report, following hearings. Since then, the Quicksilver Caucus, a coalition of state government officials, has found that amalgam separator installation rates are low unless there is a mandatory component. 'The need for dentists to install amalgam separators was well-established years ago,' Bender said. 'Yet, working with its state chapters, ADA has blocked any further mandates for separators since 2008, pretending that voluntary programs work.'"

An EPA Region 5 official was expected to testify with an estimate that the scope of the problem is much larger than the official EPA estimate—up to ten times higher than the EPA's 2002 emission inventory estimates, and a new MPP report, "Midnight Deal on Dental Mercury: How the Bush EPA's Agreement with the American Dental Association Undermines Pollution Prevention," found that the EPA's estimate of the amount of dental mercury released into the atmosphere is 4 to 6 times less than the actual amount.

Fixing the problem wouldn't take a miracle—just more than voluntary regulation. To prove that point: ten states have mandated mercury removal systems in dental offices already, according to MPP, and have been successful in preventing 95 to 99 percent of wastewater contamination.

More on mercury pollution
Coal's Other Major Pollutant: Mercury
140 Nations Agree to Create Treaty Slashing Mercury Emissions
Fact: Texas Coal-Fired Power Plants Release More Mercury Than Those In Any Other US State
Stop Dental Mercury Pollution - A Five-Step Plan