Possible provenance of "low levels of radiation"

[js_dukelow@ccmail.pnl.gov (James S Jr Dukelow)]

Well -- I was composing my rant about food irradiation exposing food to 
"low levels of radiation" when RADSAFE Digest 1567 arrived with a raft 
of other complaints about that piece of buffoonery.  I heard the same 
expression on an NPR news story yesterday and read it in a Wall Street 
Journal story (p. A3) on 27 August 1997.  The persistence of the phrase 
suggests some common source of misinformation that is being picked up 
by naive journalists.  The WSJ story says "there is an industry petition 
before the Food and Drug Administration to approve the use of low-level 
radiation to pasteurize beef", so perhaps the Journal reporter picked up 
the language from the petition.  However, on the way to looking for 
something else, I discovered another possible source of the phrase.

The American Council on Science and Health has on its Web page a white 
paper on Irradiated Foods, first written in 1982 and now in its 4th 
Edition (revised and updated in March 1996 by Richard A. Greenberg, 
Ph.D.).  Table 1 of the white paper shows radiation doses ranging from 
50 Grays (to inhibit sprouting in vegetables) up to 71000 Grays (to 
sterilize various foods so that they can be stored at room temperature 
without spoilage).  Appendix I says that a Gray is "the unit (or level) 
of energy absorbed by a food during irradiation" and that 1000 Gray = 1 
kiloGray.  Nowhere in the paper is there any indication that the human 
LD50 for acute exposure to radiation is 4-6 Sv (which for gammas would 
be equivalent to 4-6 Gy).  The paper four times uses the phrases "low-
dose irradiation" or "very-low-dose irradiation" to refer to doses of 
50 Gray to 10000 Gray for the purposes of insect disinfestation, sprout 
inhibition, delay of ripening, and eliminating Trichinella hazard in 
pork. 

The cover page of the white paper cites the contributions of 32 
reviewers of the 4th edition, all of them with appropriate credentials,
and some of them quite prominent (I figure if I recognize 
their name, they're quite prominent). 

There is a lot of good information in the ACSH white paper; they give a 
good summary of the positive case for food irradiation.  I am at a loss 
to understand, however, how "low-dose" and "very-low-dose" survived the 
review process, and I share the concerns of some of the other RADSAFE 
subscribers about the public relations implications of these kinds of 
games with words.

Best regards.

Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA

js_dukelow@pnl.gov

These thoughts are mine and have not been reviewed and/or approved by my 
management or by the U.S. Department of Energy.