Laboratory evaluation of amalgam separators

Amalgam in dental wastewater is receiving increasing security 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 the total mercury concentration in the effluent from laboratory testing. Methods. The authors evaluated the am removal efficiency of 12 amalgam separators according to International Organization for Standardization, or ISO, Standard for Amalgam Separators. Total mercury concentration in the, effluent was calculated using the mass of amalgam particles micrometers and the volume 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 mum. 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 boitotal mercury concentration and total dissolved mercury concentration in the effluent demonstrated large variations. Conclusions and Clinical Implications This laboratory evaluation shows hat 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 efficiency of amalgam separators in removing small amalgam particles, coloidal amalgam particles and ionic mercury ion.