[Beowulf] Re: Earthquakes and raised floors...

[Robert G. Brown]

On Mon, 9 Jan 2006, David Mathog wrote:

> Robert G. Brown wrote:
>
>> The whiskers are too small to filter without filters that would
>> seriously impede airflow.  Zinc whisker dust in the quantities
>> likely to be breathed in while working on or under raised
>> floors is not thought to be dangerous to humans, as humans
>> actually use tiny amounts of zinc as a nutrient.
>
> We do need a little zinc but the normal way to get it is through
> the digestive system.  Even then it is single zinc atoms that
> are absorbed, not big chunks of metal (biologically a whisker
> is a big chunk of metal).
>
> I'm a bit dubious about the claim that zinc whiskers aren't
> dangerous when inhaled.   Not because it's zinc so much (although

I agree, actually, and was worrying about the same things.  Just quoting
what I read on 2-3 docs on the website.  Zinc (like most metals) is good
for you in some forms -- an antioxidant, in fact -- and toxic in others
or in excess.  Cancer is about irritation, as well.

Anyway, either way the point is "whiskers bad", so if you do have a
raised floor make sure you have spangled galvanized tiles, not whiskery
dull dipped tiles.

    rgb

> other forms are definitely bad if inhaled) but because of
> the long needle shape (like asbestos).  Whiskers seem like exactly
> the sort of material that could get stuck in the lung and cause
> local inflamation and/or cell proliferation. Enough of the former
> effect could eventually lead to emphysema.  The latter effect probably
> has no lower dose limit, since cancers can grow up from a single cell.
> I'd be a lot more convinced if the safety claims actually
> cited experimental data (for instance with rats or mice) where the
> health effects of these whiskers was actually measured.  If there
> has been such a study I was not able to find it with a few keyword
> searches through the journal indices at our library.
>
> Regards,
>
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
>

-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu