[Amount of mercury from dental amalgam filling released into the atmosphere by cremation]

Mercury in dental amalgam filling is released into the atmosphere by cremation and is a suspected source of mercury pollution. The amount of mercury released was measured at three crematoriums. First, mercury levels in the atmosphere were measured. Mercury existed mainly in the gaseous form in ambient air. The concentration of atmospheric mercury at the three crematoriums (S, T and M) ranged from 4.3 to 19.7ng/m3, which was nearly identical to levels in our university surveyed as the control area and also to the levels of atmospheric mercury in general in Japan. Secondly, the amount of mercury release from T crematorium was estimated using official published statistical data in Japan and calculated as follows: sigma[(age specific number of dead that were cremated) x (the number of restored teeth by age category) x (mercury content per amalgam filling (0.6 g))] x (prevalence rate of restoration with amalgam). The amount of mercury released from this crematorium was estimated to be approximately 9.4 kg per year, or a daily release of 26 g into the ambient air. These results indicate that mercury release by cremation is similar to that from other man-made sources.