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Ruth -
Based on what I saw about the "irradiation machines", I think you're
probably looking at electron beams rather than gamma or X-rays. I would suspect
the reaction of electrons w/ the organic sulfides would be similar to that of
alphas.
I've heard stories (that's the best I can characterize them) of the clear
plastic windows on irradiated envelopes being browned / charred, other
plastics (floppy disks, CD's, etc.) being "melted" or deformed. To my mind the
chemical reactions in irradiated plastics are as likely, if not more likely, to
be responsible for the production of "irritants" as the irradiation of paper ...
assuming for the sake of argument, of course, that some sort of irritants are
actually produced by the irradiation process.
For what it's worth, when I was working on the Radiation Sterilizers, Inc.
(RSI) cleanup here in Decatur, GA seemingly a lifetime ago (it was only 1988),
we were working with paper products, predominantly cardboard boxes, that had
been sterilized with gamma doses in the megarad range ... and we handled those
products with no ill effects. Now granted, we were surveying them for
contamination, so we did have latex gloves, etc. ... so that may not be a valid
data point ... but in the thousands of person-hours that we worked with these
products, I don't recall anybody saying anything about any sort of
irritant.
My $0.02 worth ...
Jim Hardeman
Jim_Hardeman@dnr.state.ga.us
>>> <RuthWeiner@AOL.COM> 8/28/2002 14:04:54 >>> Re the government report that suggests that radiation may have caused some chemical changes in paper, which then produces skin irritation. High-wet-strength hard-surface paper is produced by the "kraft" process ("Kraft" is the German word for "strength"), in which the lignins are removed from wood using organic reduced sulfur compounds -- sulfides related to H2S. The sulfides are responsible, incidentally, for the noxious odor from kraft pulp mills. Paper pulp is wood with the lignins removed. White paper is bleached with chlorine dioxide or related oxidizing compounds. Low-wet-strength paper, like a lot of cardboard (and egg cartons, and the center roll for paper towels and toilet paper) is produced by a process that uses sulfites (SO3-) and removes lignins an oxidative rather than a reducing process. Alphas would almost certainly react with organic sulfide residues, but I expect the irradiation of mail would be gamma or x-ray, not alpha, if you are going to kill anthrax bacteria. Gammas would also react with organic sufides as well as with the cellulose in the paper itself, but I doubt if enough irritant would be produced to cause a physiological effect. I did my dissertation work in this area, and we had to really zap a small molecule to detect any chemical change at all. The irradiation that produces color changes in crystals is appreantly not enough to produce chemical changes that can be detected without instrumentation. X-rays produce chemical changes in photographic film, and might produce some ancillary changes that could cause irritation, but I don't know that x-ray technicians complain about irritation. Xerox is a chemical process that leaves a discernible residue (so does ink, for that matter) and I don't know of generalized complaints about chemical irritation from either. If x-rays or gamma radiation were producing an irritant in paper products, wouldn't that irritant be different for white paper, colored paper, cardboard, Xeroxed labels, handwritten envelopes, black ink, and colored inks? I'd like to see a double-blind experiment where mail handlers handle unirradiated mail that they think has been irradiated, and irradiated mail that they think hasn't been irradiated. Ruth Ruth Weiner, Ph. D. ruthweiner@aol.com Ruth Weiner, Ph. D. ruthweiner@aol.com |