HORMESIS REVISITED

Hormesis is the phenomenon of poisons being beneficial in small quantities; it is accepted for chemical and biological toxins, but in spite of overwhelming evidence it is still distrusted for radia-tion [AtE Oct 81, Jul 87, Feb 88]. In "Radiation Hormesis" (Atom, London, Apr. 1989), radiologist Prof. John Fremlin points to some data in addition to those in Prof T.D. Luckey's fundamental book Hormesis With Ionizing Radiation (1980).

Among the examples are Hiroshima and Nagasaki, where the cancer and leukemia deaths fell short of the predicted value among those who received a dose below 5 rems. Or when eggs and young fry of Canadian salmon (100,000 eggs per batch) were irradiated, the irradiated group showed greater survivability and fertility after 4 years than the unexposed control group.

What is fascinating is the disbelief of the investigators in their own evidence. Luckey's book discusses this weird phenomenon after presenting the evidence from 1,239 sources over nine decades. More such cases will be found (incidentally) in Fremlin's article: after finding that mice irradiated at 110 mrem/day survived two months longer than the (unexposed) control group, an inves-tigator rejected the result as "statistically insignificant," but accepted the results at 1100 to 8800 mrem/day, when the mice died earlier than the controls.

Prof B.L. Cohen of the U. of Pittsburgh, fortunately, lets the chips fall where they may. Running correlations of radon exposure vs. lung cancer in 411 US counties, he found the correlation nega-tive at low levels (the more radon, the less cancer). Might the data be distorted by housing differences in cities vs. the country? Cohen ran the correlation for counties without large towns: it remained negative. Perhaps the data were confounded by smoking? He took account of cigarette sales: it remained negative (cancer vs. cigarette sales was positive to the same amount). The paper is now in print, but none are so blind as . . .

If you thought the British media better than the Great American Brainwash Machine, Fremlin reports that BBC TV interviewed him on the subject three times, once for 2 ½ hours, then used only a single sentence in another program that made it appear he was warning of radiation dangers.