Bill Truesdell wrote:
>Just having CL or F in a chemical does not mean it is harmful.  Salt,
>NaCl is essential for life and most of us brush and usually swallow a
>little Fl every morning.  HCl is resident in every one of our stomachs.

        The element chlorine is present in Bill's substances  -  salt, and
aqueous hydrochloric acid in most people's stomach  -  in the chemical form
of the  CHLORIDE  ion.  The giants Davy & Faraday realised this is an
extremely different thing from that same element chlorine in other forms.
The slightly lesser giant Svante Arrhenius invented the concept 'ion'; at
the end of his oral defence of his doctoral thesis at the U of Uppsala, the
number of cannon fired at the gate  -  1  -  was to signal the minimum pass
grade, but ions have been beyond doubt for all my life and are always very
different from the uncharged forms of the element in question.
         One of the few good contributions by Barry Commoner was his early
essay pointing out that chlorine atoms  BONDED TO CARBON are very rare in
nature (and when they do occur naturally, they strongly tend have unusually
powerful properties, e.g. as bactericides), so it would appear to be a bad
idea to spread around vast amounts of organochlorines as has been done
since WW2.
        The same is even more true of the other halogens  - the elements in
the same group of the periodic table as chlorine.  Fluorine bonded to
carbon is a very different type of chemical than the fluoride ion as added
to some toothpaste, and scarcely occurs in nature.  It has unpredictable
effects  -   e.g. the drug fluoxetine as outlined by Bill.  My mentioning
that by a typo months ago should cause no more trouble, but it is an
interesting case of biological effect from an organofluorine compound.

        The main problem with organochlorine compounds, and organohalogen
compounds generally, is that they tend to accumulate in organisms.  There
are few natural detoxication mechanisms that can handle them, and few
enzymes can metabolize organohalogens.  They notoriously tend to
accumulate, often in fatty tissues.  When they trickle back out, e.g. in a
famine as fat stores are mobilized, they tend to cause a large variety of
biological harm.
        All this has been in Time-Life books for a couple decades; is in
every textbook of applied ecology; yet is ignored by any who try to judge
the toxicity of an organic compound by comparing with inorganic ions.
(Actually, the fluoride ion is about as toxic as the forms of arsenic that
have been used as poisons; and if you drink water with more than a few ppm
F- (as do millions of poor people in parts of India & China) you are liable
to malformed bones & teeth; fluoride ion is far from harmless.)

        The total experience with sythetic organochlorine compounds has
been worrying.  The ecological fate of fluvalinate has not been studied
much, and its effects on bees should have been more studied before it was
put into commerce.  Research on less toxic varroacides should be a far
higher priority.  Why would anyone disagree with that?

R

-
Robt Mann
consultant ecologist
P O Box 28878   Remuera, Auckland 1005, New Zealand
                (9) 524 2949