Allen Dick wrote:
>I'm no chemist, but I gathered -- perhaps incorrectly -- from your above
>discussion, that the presence of fluorine and the bond in the Prozac case, and
>the presence of fluorine and the bond in the fluvalinate example, were
>similar -- yet my understanding is that fluoxetine can be consumed safely and
>beneficially (in recommended small doses)

        That was the judgement of the MEDICINES regulatory authorities.  It
is a question of acceptable risk, not of claimed utter safety.  When humans
can get a direct benefit by taking a drug, and when no significant hazard
to others is entailed, side-effects are accepted when they would or should
not be for broadcast chemicals (pesticides etc) where harmful side-effects
can result on individuals and species that get no direct benefit.  The
standards are understandably different for the two types of application.
        What they have in common is F atoms covalently bound to C; and in
each case there are biological effects which could not have been
specifically predicted.  In other words, organohalogen compounds tend to
have strong biological effects but they're not foreseeable to any large
extent from the molecular structure.



> while fluvalinate should be considered
>harmful in any amount.

        Where did this idea come from?  Is there some suggestion that I
said it?


>  If this is true, how does the presence of fluorine and
>that type of bond make fluvalinate suspect as a more dangerous toxin than
>similar molecules that lack that particular feature.  I understood you to be
>saying that one feature is the major difference between fluvalinate and the
>natural pyrethroids?

        Yes  -  as a rule of thumb based on all the experience with
halogenated organic compounds, as previously mentioned, they tend to be
more harmful  -  and in some cases also more beneficial  -  than their
nonhalogenated counterparts.  A toxicologist upon seeing the 3 F atoms and
1 Cl atom in the fluvalinate molecule will tend to be more suspicious of
it.  The properties of this synthetic halogenated molecule, inspired
generally by pyrethrum but seriously different, would be expected to be
substantially different from the African daisy extract.



>Interestingly Dr. Jerry Bromenshenk discussed here on BEE-L some time back the
>toxic effects of fluorine -- as it occurs in water supplies -- on honey bees.
>This was of great interest to me since our water supply locally is
>apparently at
>or slightly above the maximum Alberta standard for human consumption by
>children
>(2ppm)

        well I don't want to seem alarmist, but if you peruse the journal
_Fluoride_ over the past decade or so you'll get (I predict) the distinct
impression that 2ppm F- is imprudent for children's drinking water.  There
are filters which can remove most of this.  Whether bees are more or less
sensitive than humans to this poison is not clear to me.


R

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