Estimated quantity of mercury in amalgam waste water residue released by dentists into the sewerage system in Ontario, Canada.
OBJECTIVE
To estimate the quantity of dental amalgam that Ontario dentists release into waste water.


METHODS
Information from a self-administered postal survey of Ontario dentists was combined with the results of other experiments on the weight of amalgam restorations and the quantity of amalgam waste that bypasses solids separators in dental offices. Algorithms were developed to compute the quantity of amalgam waste leaving dental offices when dentists used or did not use ISO 11143 amalgam particle separators.


RESULTS
A total of 878 (44.0%) of 1,994 sampled dentists responded to the survey. It was estimated that Ontario dentists removed 1,880.32 kg of amalgam (940.16 kg of mercury) during 2002, of which 1,128.19 kg of amalgam (564.10 kg of mercury) would have been released into waste water in Ontario if no dentists had been using a separator. Approximately 22% of the dentists reported using amalgam particle separators. On the basis of current use of amalgam separators, it was estimated that 861.78 kg of amalgam (430.89 kg of mercury or 170.72 mg per dentist daily) was released in 2002. The use of amalgam separators by all dentists could reduce the quantity of amalgam (and mercury) entering waste water to an estimated 12.41 kg (6.21 kg of mercury, or 2.46 mg per dentist per day).


CONCLUSIONS
Amalgam particles separators can dramatically reduce amalgam and mercury loading in waste water released from dental offices.
Adegbembo
Albert O
AO
Division of Public Health Services and Research, College of Dentistry, University of Florida, Health Science Center, Gainesville, Florida 32610-0404, USA. aadegbembo@dental.ufl.edu
Watson
Philip A
PA
D000465:Algorithms; D003723:Dental Amalgam / Q000032:analysis*; D018057:Dental Waste / Q000032:analysis* / Q000706:statistics & numerical data; D006256:Hazardous Waste / Q000032:analysis / Q000706:statistics & numerical data; D006801:Humans; D017744:Medical Waste Disposal / Q000295:instrumentation / Q000706:statistics & numerical data; D008628:Mercury / Q000032:analysis*; D009864:Ontario; D012722:Sewage / Q000737:chemistry* / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000032:analysis* / Q000517:prevention & control / Q000706:statistics & numerical data
D018057:Dental Waste; D006256:Hazardous Waste; D017744:Medical Waste Disposal; D012722:Sewage; D014874:Water Pollutants, Chemical; D003723:Dental Amalgam; D008628:Mercury