Date: Tue, 1 Feb 2000 23:51:22 +0200 From: "norman francis" <rsassoc@medscape.com> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg325$foo@default> Subject: Re: Silica Sand
There seems to be undue concern about the health hazards of using
sand for potting purposes with the exception of a few occupational
exposure situations (silicosis) sand can be considered harmless.
The health problem posed by sand is primarilly results from the
"Free Silica" content of the sand; the free silica is silica that
has not associated with other chemicals in the "sand particle";Free
Silica is found only in minute concentrations in the everyday sand
that you are likely to run across. The size of the sand particle
is crucial to its toxicity, too small and it is inhalled and
exhalled with no harm, too large and your natural defenses against
" dirt particles " takes care of it, I believe the size window
is between 3 to 5 microns for lung deposition. When I was a baby
my parents were afraid that I would be damaged because I ate so
much sand and dirt that athe asked the family doctor about it;he
said "give him a spoon" ...sage advice.
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