On Sep 7 2004, 21:28, William Donzelli wrote:
> > I suspect the hazmat team over reacted just a little.
>
> This is often the case - the hazmat guys I have talked to have been
pretty
> reasonable, but due to public pressure, they often have to put on a
show.
>
> > Mercury in elemental form is not all that dangerous ( or
> > most of us old timers would be dead or vegetables by now ).
> > It is most dangerous as salts or as long term exposure
> > to vapor.
>
> Finally someone speaks the truth! Elemental mercury mostly passes
thru the
> body in one big blob, and very little is absorbed. I think it is
rarely
> used as an antibiotic, as well.
>
> The compounds are the nasty things, as they due damage pretty
> quickly. Also, mercury vapor is also very dangerous *even in short
> periods of exposure*! The poor guys in South America that purify gold
thru
> amalgamation (and the subsequent vaporizing to get the mercury back)
tend
> to have very short lives if they are not careful.
That's because of *chronic* exposure. The risk from a single small
dose is not very high (though obviously it depends on the dose); your
body will excrete most of the mercury (but not very fast, and over the
last couple of decades, what's regarded as a "safe" level has been
reduced quite a lot). The problems come when repeated exposure causes
ingestion or absorbtion faster than you can excrete it. That's why
spilt mercury is dangerous. It gets into small spaces, and takes a
very long time (years) to vapourise (the vapour pressure is very low
but so is the toxic level).
Various mercury compounds have been used medically (eg mercuric
chloride and mercuric iodide were used as antiseptics and fungicides).
--
Pete Peter Turnbull
Network Manager
University of York
Received on Wed Sep 08 2004 - 02:41:56 BST