Re: Mercury Risk?

From: Spike Jones (
Date: Tue Mar 06 2001 - 21:46:26 MST

Ian Goddard wrote:

> IAN: 300 mcg Hg/m3 is equal to 0.3 mg/m3 of mercury vapor
> in the mouth air of some people with many amalgam fillings.
> I found this about Hg0 in a book at the library, it states:
> "OSHA limit in workplace air: 0.1 mg/m3"
> This appears to indicate that if you have many amalgam
> fillings, the Hg0 in the air you breath could be 3 times
> over the OSHA safety limits. This appears to define unsafe.
> It appears that the claim on anti-amalgam webpages was true.

"Bullshit," said Pooh, in a more forthright manner than was
his custom.

Not you, Ian. Im a big fan of your artwork. The honey-guzzling
bear is referring only to the anti-amalgam websites. I am not
a dentist, dont play one on TV, I have no stock in... Amalgam
Amalgamated. {8^D But do allow me to present a ROM
explaining why I have not had my fillings removed.

First, 300 mcg Hg/m3 is not equal to 0.3 mg/m3, but let
us ignore that, since I didn't use it in my calcs.

A typical SCUBA tanks is about... what, 20 liters? And they
fill those to about 200 atmospheres, so thats 4000 liters or
4 cubic meters of air, and a tank lasts about an hour or so,
and if one is at an average depth of 10 meters thats
2 atmospheres so on the surface a tank should last about 2
hours, eh? So we breathe about 2 cubic meters of air per
hour? A refrigerator is about 2 cubic meters and I can easily
imagine a prole trapped in one to last about an hour, so we
are likely in the right order of magnitude.

If the OSHA limit is 0.1 mg per m^3 and our fillings
contributed even half of that, or .05 mg/m^3, then they
would be evaporating at 0.1 mg per hour. Even if we
ignore the fact that amalgam is a mixture of metals {thus
the name} and assume them pure mercury, 0.1 milligrams
per hour is about 2.4 milligram per day is about 900
milligrams per year.

So how big is a filling? A cavity is (conservative estimate?)
20 cubic millimeters? Assume 50. Mercury is about 13
gram/cm^3 so a big filling is 800 milligrams? I have about
a dozen fillings and so thats about 10 grams of amalgam.
So if they dissolved fast enough to provide half the OSHA
safe limit, a typical head of fillings would be gone in about
11 years. Some of my fillings are over 20 years old and
I cant tell they are any smaller than they have ever been.
They must be smaller, since they do wear, but the delta is
not apparent.

Nowthen, Bobby Fischer had his fillings removed, and he
is the greatest chess player of all time, however I am not
convinced of the danger. {8-] spike

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