Sources of Mercury Waste in Dental Offices
Amalgam, which is the most commonly used restorative material, is comprised of nearly 50 percent mercury. Small quantities of mercury are also found in fluorescent bulbs and mercury-containing devices, such as thermostats, thermometers, switches and relays.
Health and Environmental Effects from Mercury
Mercury is highly toxic to humans and wildlife. In humans, mercury is toxic to the nervous system (brain and spinal cord), particularly the developing nervous system of a fetus or young child. Effects seen in children with elevated mercury exposure include lowered cognitive abilities, impaired hearing, and poor coordination. Chronic, elevated exposure to mercury also affects the kidneys, liver, and immune system.
Environmentally, mercury is a concern because of the many ways the chemical can come into contact with soil, water, surface water, and air as a result of improper disposal. When mercury waste is incinerated, the volatilized mercury precipitates to the environment and will enter the soil, surface waters, and food chain. When mercury waste is disposed of down the drain, there is potential for contamination of water and/or sludge at the wastewater treatment plant or the septic system.
Infectious Waste in Dental Offices
Amalgam should not be treated as medical waste, nor should it be disposed in red bag waste receptacles. Amalgam that is placed into red biohazard bags is incinerated or autoclaved. If amalgam is incinerated, the mercury will volatilize and enter the atmosphere. If amalgam is autoclaved, the volatilized mercury will escape from the autoclave when the door is opened, presenting an immediate health hazard to dental office staff.
Proper Management of Mercury Waste from Dental Offices
Best Management Practices for Amalgam
Pollution prevention alternatives include recycling waste amalgam particles, and using mercury-free restorative materials. Here are a few best management practices for managing waste amalgam:
- Place extracted teeth with amalgam restorations in the CONTACT AMALGAM container, not in the red bag waste container.
- Use amalgam substitutes (plastic or porcelain composites) when they are appropriate.
- Do not store waste amalgam in used radiographic fixer. Fixer is considered a hazardous waste, and must be managed as a hazardous waste.
- Do not discard scrap amalgam down the drain. Mercury and amalgam particles should be kept out of the drain and the trash
A NH Hazardous Waste Rule change [Env-hw 802.2(b)] became effective October 13, 2001, which allows an exemption for mercury-containing dental amalgam generated by small quantity generators, provided that the waste is recycled. Therefore, it is in the best interest of dental offices to recycle all amalgam waste.
- Recycle scrap amalgam through an amalgam recycler. Place all scrap amalgam in containers labeled "Waste Amalgam for Recycling."
- Any defective amalgam capsules that cannot be emptied should be placed with the non-contact scrap amalgam so they can be recycled. Be sure to check with your amalgam recycler to see if they will take capsules with your scrap amalgam.
Solid Waste Disposal
After mixing amalgam, the empty amalgam capsules containing no visible amalgam may be disposed of in the standard or normal trash receptacle.
Keep a mercury spill kit in the dental office. Before purchasing a spill kit, verify from the vendor that it contains complete instructions on how to perform a mercury spill clean up. Train several staff members in the dental office in proper spill clean up procedures.
Best Management Practices for Mercury-Containing Devices and Products
A number of office maintenance items contain mercury, such as fluorescent lamps, thermostats, switches, and relays. Spent/replaced mercury-containing products generated by businesses, industry and institutions may not be disposed of as a solid waste and should be handled as a "universal waste" or hazardous waste. If managed as a hazardous waste, they must be properly stored, listed on a manifest, and disposed of by a hazardous waste hauler. If managed as a universal waste, the fluorescent bulbs and devices must be kept unbroken and be collected by a universal waste handler or self-transported to a recycling facility (no need for a manifest). Universal wastes are exempt from the NH Hazardous Waste Rules, but must be stored properly to prevent release, labeled correctly, self-transported, or shipped with a bill of lading.
The DES fact sheet Waste Mercury-Containing Lamps: Management Requirements for Handlers and Transporters provides all requirements and regulations for proper disposal of these items.
DES maintains a list of fluorescent lamp and ballast recycling facilities. By using mercury-free alternatives whenever possible, the issue of proper disposal of mercury waste is eliminated at the source.
2002 NH Legislation for Mercury Pertaining To Dental Offices
For More Information
- New Hampshire Department of Environmental Services
Pollution Prevention Program
- New Hampshire Dental Society
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