From: houle@nmt.edu (Paul Houle)
Subject: Re: NEWS: Radioactive Sand Proves Nuclear Reprocessing Unlawful
Organization: New Mexico Tech
Date: Mon, 14 Sep 1992 15:35:11 GMT

In article <1992Sep14.042142.11201@sugra.uucp> ken@sugra.uucp (Kenneth Ng) writes:

>Wrong, plutonium has been created by *NATURAL* reactors many times in the
>history of the planet Earth.  Reference articles in Scientific American a
>number of years ago.

	I think that this is being a little pedantic.  I'm only aware of 
several "natural reactors" which all occured in the same area (I believe in
what is a uranium mine today in Gabor).  It is quite possible that it
could have happened in other places.  One must remember that the ratio of
U235/U238 has changed considerable since the time (hundreds of millions
of years ago) that this happened,  so it can't happen anymore.

	There are very small quantities of plutonium in most uranium ores,
which I believe is produced in very small quantities by nuclear transformation.
I think that most of the virgin plutonium produced by supernovae has probably
decayed by now.  Does anyone have a good estimate for what the 'natural'
plutonium inventory in the Earth's crust is?  How does this compare to
anthropogenic quantities?

	No naturally concentrated (read economic) deposits of plutonium
exist,  so one could safely say that all concentrated forms of plutonium on
Earth are our fault.

	Actually,  this natural/synthetic debate is an interesting one if
we look at it from the viewpoint of ecology.  Living systems have evolved to
be able to deal with the molecules that have existed in the biosphere for
millions of years;  so we get bacteria that eat oil seeps and enzymes in
your gut and liver that metabolize alcohol.  When we introduce molecules that
are radically different from anything that has existed in significant
quantities on Earth,  this can create problems.  DDT is probably the canonical
example;  but CFCs are also 'alien' as well as a host of other molecules
we create ranging from polyacrylates to buckyballs (maybe) to LSD.  (I talked
to Dr. Huffman at U of A about buckyballs,  and he isn't sure about why
buckyballs haven't been observed in the biosphere;  one theory is that they
cannot be produced in an oxygen-rich atmosphere,  and the other is that there
might be a natural process that breaks them down.  If the first happens to
be the case,  we might want to consider what the effect of introducing a
new class of molecule to the biosphere is)

	Some of these molecules are very alien (such as CFCs),  while others
are chemically similar to natural molecules (like LSD).  Some of them are
harmless to organisms (CFCs) but cause other problems,  whereas others are
quickly metabolized and broken down.

	So far as the danger of natural molecules go,  a case can be made that
most plant and animal poisions have evolved to have an aversive effect;  not
to kill.  Only a handful of mushroom species,  for example,  are deadly
poisionous in the typical quantities that are consumed.  The majority of them
make people extremely sick,  or have psychoactive properties that are
aversive to most animals (psilocybin;  just ask my friend who ate too many
Stropharia Cubensis about the aversive effects of it).  Because of the
phenomenon of co-evolution,  animals (and people) tend to evolve resistance
to compounds in the environment.  Biochemical wars have been fought long
before the dawn of man.

	Of course,  man's effects on the biochemical wars are interesting.  The
evolution of,  say,  BT toxin parallels our development of many synthetic
pesticides and antibiotics.  By using our chemicals on a wide basis,  we seem
to be accelerating the natural process of evolution of chemical resistance in
them.  I think it is amusing that the chemicalization of agriculture has not
prevented pests from taking 1/3 of the crop -- just that it has left farmers
with a big bill for pesticides.

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