Edouard Bastarache on tue 9 apr 02
Hello Gavin,
" To Edouard Bastarache, irreducible Quebecois, I would pose the following
question: by what route and at what rate do cations which are included in
silicate frits leave the body, if inhaled in small particles which do not
clear effectively by the throat? I presume that any such material except
the most refractory (possibly zirconia) will release its load of stuff by
ion-exchange if immersed in lung fluid for a long enough time. All such
material will also clear from the body by various routes, given a long
enough time. So in my model, it is a matter of competing
rates. Presumably the uptake will be higher the finer the particles, so
the danger may be worst with very fine powders. We are given to understand
that some large fraction of pottery frits may come in very fine particle
sizes.
Gavin"
There is no "fits all" answer to your question.
Solubility is a very important factor, indeed
There is one general principle though:
"As a general rule, the smaller the diameter of particles, the more
efficient
is the pulmonary clearance by the bronchi and acini. The bronchial and
alveolar retention of particles is the result of two opposing factors,
deposition
and clearance. Retention of dust will be at its peak, depending on the
nature
of dust, for the particles whose diameter ranges from 0.5 to 3 microns."
So, you will have to check cation by cation.
Later,
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
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