lead hazard - changed

[Robert Myers <rmyers@inetone.net>]

At 09:41 AM 9/11/98 GMT, you wrote:
>In message <707b6fce.35f83382@aol.com> MSV96@aol.com writes:
>
>> << MoS2 is molybdenun disulfide and is a graphite substitute in lubricants.
>> While I would not recommend eating it, getting a bit of moly containing
grease
>> on your hands shouldn't be particularly hazardous. >>
>>
>> Hope Bob's clarification sent to me privately takes care of some fears
raised
>> WRT lead hazards in grease. (Forwarded with his permission.)
>
>Lead is hazardous to a degree to adults, but its major threat is not to
>adult brains - it's to _developing_ ones.  That's why lead levels in
>children are monitored rather than lead levels in adults, and why the
>German note on Audi's original equipment grease tubes specifically
>mention children.

Agreed, Phil.  Lead is a hazard.  Particularly for children.  However, the
discussion was about moly, not lead.

>If you _do_ come into contact with it in large quantities, I think the
>medics recommend run-of-the-mill carbonate-based stomach powders -
>there's some sort of precipitation effect.

This is just wishful thinking in most cases of lead exposure.  Lead
carbonate (PbCO3) which should (supposedly) be formed by this treatment is
no less soluble than most other leads compounds.  The carbonate would have
little effect.  There are, however, a few lead compounds which exhibit a
"reasonable" solubility level.  These include lead nitrate [Pb(NO3)] and
lead chloride [PbCl2].  Neither of these is would be in automotive use
AFAIK.  

Lead in old-fashioned leaded gasoline (petrol, Phil :-)) was present as
tetraethyl lead in which four ethyl groups are attached to one lead atom
via a rather covalent bong [Pb(Ch2-CH3)4].  It's purpose was to act as a
ready source of free radicals (no, not Che Guevara) to help the main fuel
start burning more readily and smoothely.  This relatively unstable
compound is a definite hazard.  That's part of the reason that its use has
been nearly ended.

>But wash your hands well before going near your kids.

Good idea most of the time anyway.  After all, our hands may not be clean
but we know where they've been.  :-)


___
   Bob
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