On December 15, 2016, the Obama administration issued the Mercury Effluent Rule, the EPA’s final rule to address mercury discharge from dental offices into publicly owned treatment works (POTWs).
On January 20, 2017, only hours after taking office, the Trump administration issued a memo to federal agencies “immediately withdraw” final rules that were sent to the Office of the Federal Register but had yet to be published. On the following Monday, the EPA withdrew the Mercury Effluent Rule, but did so without giving public notice and an opportunity to comment – a requirement of repealing a final rule.
The Natural Resources Defense Council (NRDC) is suing the EPA for “illegally rescinding a rule that would protect the public from more than five tons of mercury discharges each year.”
Aaron Colangelo, litigation director at NRDC said, “The Trump White House ordered the EPA and other agencies to violate the law. That puts Americans at greater risk of exposure to this dangerous neurotoxin, which can do harm even in tiny amounts.”
Now, if you’re like me when visiting the dentist, you’re more concerned about if you have any cavities than what goes down the drain when the dentist tells you to “spit.” But dental clinics are the primary source of mercury discharges to POTWs.
It happens when new fillings are placed or drilled out. Dental offices may discharge the mercury-containing mixture into the chair-side drain which is then flushed into sewers that drain into POTWs. This frequently results in mercury partitioning into sludge - the solid material left over after wastewater is treated – which is then incinerated, sent to a landfill or used in the land application of sludge.
Approximately 5.1 tons of mercury each year makes its way into the environment from the dentist office.
The Mercury Effluent Rule requires for dental offices that discharge to POTWs to use an amalgam separator that captures mercury and other metals, and not discharge scrap amalgam. It is a practical and low-cost solution that is widely supported by dental providers
Mercury is a neurotoxin that can damage the nervous system and disrupt brain function depending on exposure and health of the person exposed. The EPA lists effects of overexposure to elemental mercury (from the air), methylmercury (from fish) and mercury compounds (industrial processes).
Mercury pollution is widespread and originates from diverse sources. The EPA expects compliance with the Mercury Effluent Rule will reduce 5.1 tons of mercury discharge and 5.3 tons of other metals in dental waste amalgams going to POTWs.
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