Estimation of mercury dose by a novel quantitation of elemental and inorganic species released from amalgam.

Amalgam fillings constitute, after food, the main source of exposure to mercury for the general population. An evaluation of potential health risks has to be based on the dose of mercury released from the fillings. This dose is estimated by a new procedure of mercury speciation which elutes the released elemental and inorganic mercury with solvents of different polarity (paraffin and saline). In vitro tests with spherical amalgam pellets have shown that mercury release into the solvents is linearily correlated to time and amalgam surface area. Doses estimated in volunteers by this method average 4.5 micrograms/day (range 0.3-13.9), as compared to a dose of 3.4 micrograms/day (range 0.1-11.8) measured conventionally in the oral air. The aforementioned dose, combined with the nearly equal mercury uptake from food, is below the acceptable daily intake of 40 micrograms for all forms of mercury.