From: Paul Dietz <dietz@interaccess.com>
Newsgroups: alt.folklore.science,sci.physics,sci.chem,sci.energy,
	sci.space.policy,sci.astro,sci.med
Subject: Re: Which is more toxic - plutonium or radium?
Date: Sun, 12 Oct 1997 18:03:36 -0500

Steven B. Harris wrote:

> Is this a trick question?  Because we don't eat much radium, that's
> why.  The stuff accumulates in uranium ores (since it's a uranium decay
> product) but isn't found in other places that don't have the uranium.
> Uranium ores are pretty much buried and isolated.  They don't get into
> your food supply.

Yes, it does get into the food supply.  Listen up...

Phosphate rock often contains elevated levels of uranium,
sometimes exceeding 100 ppm.  Indeed, some phosphate rock
deposits in the SE United States had their uranium extracted
as a byproduct at one point (the acid solution after sulfuric
acid digestion was mixed with kerosene/tributyl phosphate
which selectively binds to the uranyl ions). They don't do
this now; it's not economical.

The ores also contain radium, of course.  Radium acts a lot like
calcium.  Some ends up in the calcium sulfate waste stream (so watch
where your gypsum comes from), but some also stays in the superphosphate
fertilizer (as does polonium and other decay products).  The isotopes
that stay in the fertilizer end up on farmland, and some go into the
crops.

It is estimated that the global dose from phosphate fertilizer
radioisotopes each year is roughly half the total global dose (over all
years) from the Chernobyl accident (source: IAEA).

	Paul

From: Paul Dietz <dietz@interaccess.com>
Newsgroups: alt.folklore.science,sci.physics,sci.chem,sci.energy,
	sci.space.policy,sci.astro,sci.med
Subject: Re: Which is more toxic - plutonium or radium?
Date: Mon, 13 Oct 1997 20:35:14 -0500

Steven B. Harris wrote:

>   Ye Gods.  Thanks for the nightmares.  Unlike the case with mad cow
> disease (BSE), there's not a heck of lot I can do about this to protect
> myself, is there?  I can't very well stop eating all commercial
> produce....


Don't worry about the radium.  Worry more about the *cadmium*
in the fertilizer.  Cadmium is also elevated in phosphorites,
and for some farmland the time until the cadmium accumulates
enough to start affecting plant growth is on the order of a
century (this depends on the particular location being mined).

It would be better to more fully purify the phosphate to remove
these impurities.

I understand Florida has about 700 million tons of phosphogypsum
that has accumulated as a byproduct of phosphate fertilizer
manufacture.  It can't be used for much of anything because of
radon.

	Paul