Why is amalgam being regulated?
Most amalgam fillers used contain trace amounts of mercury which is a potent neurotoxin with a wide range of health effects. Mercury-containing amalgam entering the wastewater from dental offices can pass through wastewater treatment plants by becoming embedded in a byproduct of the wastewater treatment process known as sludge. The mercury-containing sludge can then be introduced to the environment through various modes, such as through surface water discharge or direct land application. When released into the aquatic environment, certain bacteria can change the chemical composition of mercury into its highly toxic form of methylmercury which bioaccumulates in fish and shellfish. When fish and shellfish are consumed it increases human exposure to methylmercury.
Who does this rule apply to?
Dental offices including schools and clinics that discharge into a municipal sewage treatment plant.
Who does this rule not apply to?
Mobile dental units, or where the practice only consists of the following dental specialties:
- Oral Pathology
- Oral and Maxillofacial Radiology
- Oral and Maxillofacial Surgery
What does this rule require of my dental office?
1. Dental offices must operate and maintain an amalgam separator, and must not discharge scrap amalgam or use certain kinds of line cleaners.
2. Dental offices must implement the following “Best Management Practices” recommended by the American Dental Association specified in 40 CFR 441.30 or 441.40
- Waste amalgam including, but not limited to, dental amalgam for chair side-traps, screens, vacuum pump filters, dental tools, cuspidors, or collection devices, must not be discharged to a publically owned treatment works (POTW).
- Dental unit water lines, chair-side traps, and vacuum lines that discharge amalgam process wastewater to a POTW must not be cleaned with oxidizing or acidic cleaners, including but not limited to bleach, chlorine, iodine and peroxide that have a pH lower than 6 or greater than 8.
3. Dental offices must complete a “One-Time Compliance Report for Dental Discharges” to ensure compliance
How long do I have to comply with this rule?
- Dental dischargers operating under the same ownership since June 14, 2017 must be in full compliance by July 14, 2020
- New dental dischargers (in operation after June 14, 2017), or existing dental dischargers that have had a transfer of ownership (after June 14, 2017) must be in full compliance within 45 days after: the opening date of the new dental facility; or the effective date of the transfer of ownership, respectively.
Where can I find more information about this rule?
Please visit the U.S. EPA webpage for Dental Effluent Guidelines.