Aucbvax.1914
fa.energy
utzoo!duke!decvax!ucbvax!OAF@MIT-MC
Wed Jun 24 15:34:22 1981
short message no digest
Date: 23 Jun 1981 10:23:37-EDT
From: cjh at CCA-UNIX (Chip Hitchcock)
Subject: lung pollution
I did some work on this while studying inhalable sprays and particulate
sprays that weren't supposed to be inhaled. This is a fair summary
although I won't promise the precise accuracy of the details.
Basically, the lungs themselves are far too fragile to support any
cleaning mechanism; if you take a look at a lung tissue slide you'll
see it's mostly empty spaces separated by very thin walls. (If you
look at a slide from someone who had silicosis, the walls are no thicker
but the spaces are much larger.) The lungs are protected by a layer of
mucus in the pharynx and trachea; this material is extremely sticky
(so it catches much of what comes by) and is continually born upward
to the top of the esophagus where it can be swallowed or coughed out.
Coughing is the only mechanism that can clean the lungs themselves, and
it's not very effective for anything that has actually gotten down into
the individual air sacs.
Given that a gram of plutonium would be a cube between a third and a
half of a centimeter on a side, a microgram all together would be
(if cubical) 33-50 microns on a side. This is within the range for
dust particles to be trapped by the mucus and carried away from the
lungs (my recollection is that above 150 microns particles get stoppped
near the top of the pharynx and only below 10-20 microns do many of them
get into the lungs), but dust particles should be much easier to seize and
carry upwards than something as dense as plutonium. Also, particles this
large are unlikely to be windborne; smaller particles in quantities
greater than one are more likely to be an inhalation danger.
Physical erosion can be halted and perhaps even healed over time; this
is why smokers are encouraged to quit even if they've been at it a while
(At the least, each additional puff adds to the load of particles tearing
up the lungs.) But lightweight ash would be much easier to encyst and possibly
expel than plutonium. Also, encystment alone doesn't help, since lung
tissue is thin enough that I would expect even alpha particles to smash
through several layers. To make matters worse, the plutonium can also
be chewing up random blood cells in the vicinity, although a fine dusting
like this is less apt to damage enough blood cells to cause serious effects
in the cells' natural lifetime of 3 weeks.
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