RE: [CPEO-MEF] DU munitions

[dhenshel@indiana.edu]

Susan -
You have an interesting way of looking at things.  DU may have less 
U235, and more U238, but that doesn't mean it's not radioactive.  It's 
just less radioactive.  Even if  it were 100% depleted of U235, which is 
never the case, by the way, it would still give off 1/10 the dpm of the 
original stuff, given an equal amount of U238 left behind.  In other 
words, U238 is 1/10th as radioactive as U235.  Not 0% radioactive by 
comparison, 10% by comparison.  (This number is based on the half-life, 
which is only an order of magnitude, 10x, different.)  I don't know what 
you do, but I am a toxicologist working on environmental pollutants.  I 
look at net toxicity,
which means potency x concentration.  If the potency is 1/10th, but the 
amount distributed is 10X (or more, because of this mistaken belief that 
U238 is "not radioactive" and therefore it seems to be being liberally 
sprinkled in places where little radioactivity was before), then you end 
up with the same net dpms over a given period of time.  Off the top of 
my head, I do not recall the difference in specific activity of the two 
isotopes, but I do not recall that the net energy was all that different 
for every disintegration.  Thus, please stop railing about DU being not 
radioactive. It is radioactive, just 10x less so, pound for pound of 
U235 and U238. 

The problem with this is that while most exposures  are expected to be 
"low dose radioactivity", it's also a chronic exposure for folks who 
live in DU-bombed, or DU-contaminated areas.  

If you look through the literature, there is not a whole lot understood 
about the health effects of long term, low dose radioactive exposures.  
Most toxicologists have focused on "bomb-like" high dose acute 
exposures, mostly because that's what we as a world people have had most 
experience with.  (In 25 years, however, I expect there to be a huge 
number of papers on long term low dose exposure.  Unfortunately, it's 
today's exposees who will be the
subjects of those papers.)

Further, Uranium is still a non-essential heavy metal.  Heavy metals 
have both common mechanisms of action and actions unique to certain 
metals.  In common are the interference with Calcium metabolism and 
calcium-mediated physiological actions (of which there is a multitude, 
including secretion of hormones and neurotransmitters and cytokines).  
Also in common are the storage into bone and kidney, usually resulting 
in kidney toxicity in the long-term.  There's also the potential for 
interference with protein structure and function due to the tendency for 
heavy metals to bind to sulfurs, which can disrupt disulfide bridges 
which control three dimensional protein structure.  Due to the first and 
the third mechanisms above, IF U
can get into the immature brain (which is not well protected in utero 
and shortly after birth), U (U238 or U235) has the potential to disrupt 
a host of critical processes controlling brain development.

Now, there are tidbits in the literature here and there (mostly there, 
and mostly a long time ago) that indicate that if we just looked for the 
long-term low dose effects of heavy metal toxicity from U, even as DU, 
it will probably be there.

Given all that, I really think that we (as the human race) need to be a 
lot more careful about our profligate use of DU.  We don't know enough, 
but what we do know says it's likely to be a lot more dangerous, in a 
sub-lethal way, than your reply implies.  And given it's long half-life, 
human life, and animal life, will have to live with our (ab)use of DU 
for thousands of generations to come.

Diane Henshel