Laboratory evaluation of amalgam separators.
BACKGROUND
Amalgam in dental wastewater is receiving increasing scrutiny from regulators because of national, state and local initiatives to reduce or virtually eliminate the discharge of mercury and mercury-containing items into the environment. Amalgam separators are considered to be one means of reducing the amount of amalgam that dental offices discharge into sewers. The purpose of this study was to evaluate the amalgam removal efficiency of commercially available amalgam separators and the total mercury concentration in the effluent from laboratory testing.


METHODS
The authors evaluated the amalgam removal efficiency of 12 amalgam separators according to International Organization for Standardization, or ISO, Standard 11143 for Amalgam Separators. Total mercury concentration in the effluent was calculated using the mass of amalgam particles larger than 1.2 micrometers and the volume of effluent, together with U.S. Environmental Protection Agency, or EPA, Method 245.1 for amalgam particles smaller than 1.2 microm. Total dissolved mercury also was determined.


RESULTS
The results show that all 12 amalgam separators exceeded the ISO 11143 requirement of 95 percent amalgam removal efficiency. Statistical differences were found in the efficiencies of the separators. Both the total mercury concentration and total dissolved mercury concentration in the effluent demonstrated large variations.


CONCLUSIONS
This laboratory evaluation shows that amalgam separators removed at least 96.09 percent of the amalgam in samples with particle-size distribution as specified in ISO 11143. Total mercury concentration and total dissolved mercury concentration in the effluent varied widely for each amalgam separator. Additional research is needed to develop test methods to evaluate the efficiency of amalgam separators in removing small amalgam particles, colloidal amalgam particles and ionic mercury in solution.
Fan
P L
PL
Division of Science, American Dental Association, Chicago, Ill 60611, USA. fanp@ada.org
Batchu
Hanu
H
Chou
Hwai-Nan
HN
Gasparac
William
W
Sandrik
Jim
J
Meyer
Daniel M
DM
D003723:Dental Amalgam; D003748:Dental Equipment; D018057:Dental Waste; D004526:Efficiency; D017744:Medical Waste Disposal / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D008628:Mercury / Q000032:analysis; D010316:Particle Size; D014481:United States; D014484:United States Environmental Protection Agency; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods / Q000592:standards; D014874:Water Pollutants, Chemical / Q000032:analysis; D014877:Water Pollution, Chemical / Q000517:prevention & control*
D018057:Dental Waste; D017744:Medical Waste Disposal; D014874:Water Pollutants, Chemical; D003723:Dental Amalgam; D008628:Mercury