Managing mercury in dental waste

Dentists use mercury in dental fillings and must take steps to ensure mercury isn't discharged to wastewater treatment plants, which are not designed to remove it from wastewater. In June 2017, the federal Dental Effluent Guidelines rule began requiring dental practices to install amalgam separators to keep mercury out of their wastewater. For more information on the wastewater requirements for dental offices, see the Wastewater pretreatment page.

Amalgam separators certified in Minnesota

The MPCA developed approval criteria and a process that was approved by the MDA Environment Committee in April 2012: PDF icon Minnesota Amalgam Separator Approval Procedure

In order to be on the list of approved products, a separator must:

  1. be tested against the current ANSI/ADA specification by an accredited testing laboratory
  2. meet the current ANSI/ADA specification
  3. have at least a 99% amalgam particulate recovery rate, calculated as the overall average of the three empty and three simulated full tests in the specification
  4. be issued a certificate by an accredited certification body.

The MPCA sent the procedure to manufacturers of amalgam separators and requested submission of test reports and certificates. The MPCA has received documentation from manufacturers demonstrating that the following separator models meet the approval criteria.

* the listed Solmetex Hg5 separators are no longer being sold, but the CC-5M Collection Container is available and is approved for use with all installed Solmetex Hg5 separators.

Waste management for dental offices

Dental amalgam waste and pretreated dental wastewater (wastewater that has passed through a separator) are classified as universal waste. Dental clinics on septic systems must install an amalgam separator and segregate post-separator treated wastewater for management as universalwaste or delivery to a local wastewater treatment facility that is willing to accept it.

In the seven-county Twin Cities metropolitan area, solid/hazardous wastes and wastewater from dental clinics are subject to regulation by the counties and the Metropolitan Council, respectively.

Mercury emissions from cremation

If someone chooses to be cremated after they die, any mercury amalgam in their dental fillings can be vaporized and emitted as air pollution. One study estimates that more than 95 pounds of mercury was emitted in 2014 by cremation in Minnesota.