The University of Texas Health Science Center at San Antonio
In the Fall of 2000, the Environmental Health and Safety Department at UTHSCSA began investigating the amounts, types and locations of mercury-bearing materials in use. In addition to amalgam, sources of mercury include thermometers, manometers, switches and other electronic components. Amalgam was found to be the predominant source of mercury waste. With over 400 dental chairs, the UTHSCSA Dental School has a great opportunity to educate future dental professionals relative to the environmental hazards of mercury waste. At the same time, we can take the lead in administrative and technological advancements in order to reduce and recycle mercury waste, thus eliminating it from the waste stream.
Quarterly wastewater treatment checks conducted by the San Antonio Water System document that we have successfully complied with current EPA method 7470 standards for effluent mercury. After consultation among the Dental School faculty leadership, the university engineers, the environmental representatives, and potential contractors, it was decided that UTHSCSA should and could become an environmental leader in the capture of mercury-bearing waste from the dental operatories of the school. The goal was set to achieve institutional limits of less than 10 micrograms/liter of mercury discharge.
UTHSCSA is the first university in the country to develop and install a comprehensive mercury dental amalgam management system. This innovative program uses the waste management, recycling, pollution prevention, and pollution controls espoused in the Pollution Prevention Act. The system will capture mercury-bearing waste in the following five waste streams:
- Elemental or bulk mercury.
- Unused amalgam.
- Used amalgam caught on the chair-side trap.
- Amalgam sludge that settles in vacuum pump traps.
- Wastewater discharged from vacuum systems.
The first three waste streams were easy to identify and regulate. The goal of this first phase is to recover as much of the unspent amalgam as possible before it enters the vacuum system traps. Chair-side traps, in combination with amalgam separation units, have the potential to capture virtually all of the mercury waste discharged from dental facilities.
We experienced a drop in mercury discharge from 50 micrograms/liter to less than 10 micrograms/liter. The mercury bearing amalgam is now being sent to a recycler. Equally important is the educational benefit being provided to current and future producers, the dentists.
Details of Reductions
Additional Information :
The value of educating the dental community, though immeasurable, is undoubtedly more cost effective than removing mercury from the environment once it has been introduced.