Dentists create mercury bearing amalgam waste when they drill out old mercury amalgam fillings.
Most of this toxic waste is captured in coarse filters in the dental operatory. These coarse filters have to be cleaned or replaced frequently or they will clog and the dentist will lose suction. Unfortunately, in many dental offices this hazardous waste is thrown in the trash or put in the biowaste containers for incineration. The mercury bearing amalgam waste in fine particulate gets past these filters and goes down the drain into the sewer, or dentists septic, system. All of these waste streams eventually discharge the mercury in the amalgam waste into the air and water in every community where there is a dental office or clinic.