For one week these web pages promoted the idea that mercury amalgam fillings give up over 50% of their mercury within 4-6 years. This was an error. If someone presents you with such an idea, it is not true by what I know from the scientific data.

It is possible for a collection of mercury amalgam fillings to give up 100's of milligrams of mercury over some years. What I believe to be a valid critical interpretation of the data from SJ Marshall et. al. is found in the page: "Where Does the Mercury Go ?".

My mistake was not knowing the implied percentage conventions used by amalgam researchers. When a researcher quotes "Residual Hg", the numbers are normalized to the mass of the entire amalgam volume measured. The number is not normalized to the initial amount of Hg in the filling.

Let me explain by example. A filling with 50% mercury content is installed. Later it is removed and analyzed for residual mercury. 48% mercury is quoted as the Residual Hg. That number would be normalized to the entire mass of the retrieved amalgam.

If the residual number were to be normalized to the initial mercury content, the value quoted would be 96% of the 100% at time of installation.

Confused ? Now you know how I made my mistake.