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From: walton@tybalt.caltech.edu (Steve Walton)
Newsgroups: misc.consumers,sci.bio,sci.misc
Subject: Re: pesticides
Message-ID: <3667@cit-vax.Caltech.Edu>
Date: Mon, 17-Aug-87 19:49:13 EDT
Article-I.D.: cit-vax.3667
Posted: Mon Aug 17 19:49:13 1987
Date-Received: Wed, 19-Aug-87 01:32:47 EDT
References: <3620@cit-vax.Caltech.Edu> <2207@zeus.TEK.COM> <3102@blia.BLI.COM>
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In article <2207@zeus.TEK.COM>, dant@tekla.TEK.COM (Dan Tilque) writes:
> 1.  Because humans have selected and bred for more insect resistant plants, 
> the amount of natural insecticides in plants has actually increased over
> the years.

Reference?  It seems that we've actually succeeded in making plants more
attractive to pests (bigger and easier to harvest fruit, for example),
rather than less.

> 2.  The natural insecticides are concentrated just in the plants, not
> spread indiscriminately about the countryside.

An excellent point; I don't disagree that there are other good reasons
than human cancer risk (such as near-extinct bald eagles) to ban
certain insecticides.  I was responding, you'll remember, to a posting
criticizing the EPA for not making adequate cancer tests on
insecticides. 

In article <3102@blia.BLI.COM> heather@blia.BLI.COM (Heather Mackinnon) writes:

>3.  We evolved with the natural insecticides in plants in the levels they
>    are found in plants.

But they are still carcinogens, according to laboratory tests.  If the
fact that we evolved with them was relevant, we should show some
resistance to their carcinogenic effects; we don't. 

>    Most experiments on carcinogens show how the chemicals work in isolation.

Which brings up another interesting point: it seems according to
recent work that actual cancers are not caused by one agent, but by
several working in sequence.  See Science '8n's cover story on cancer
about a year ago.  Work is proceeding on defining exactly the sequence
of cell damage which causes cancer, and finding the causative agents
of each step.  Long and hard work, as you can imagine.

    Steve Walton, guest as walton@tybalt.caltech.edu
    AMETEK Computer Research Division, ametek!walton@csvax.caltech.edu
"Long signatures are definitely frowned upon"--USENET posting rules