Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.9
Conclusions

[" ‘Where the radiation level is greater, cancer risk is invariably less.’ Namby and Soman 1990]

"When it became obvious that gross mutations, genetic diseases, and monsters were not produced by exposure to atomic bombs, the most feared aspect of ionizing radiation came from the prediction of cancer induction 5 to 30 years following exposure. With the exception of medicine, the moral consequences of atomic bombs and accidents in the nuclear industry roused societal rejection of all activities involving ionizing radiation. Acceptance of radiation hormesis will greatly change attitudes in government, industry, medicine, and public health. Hopefully, government agencies will realize it is counter productive to use guidelines based upon the discredited linear models."

"The Delaney cancer clause states that an agent should be considered carcinogenic ‘...if it is found, after tests which are appropriate for the evaluation of the safety of food additives, to induce cancer in man or animal...’ The limits of ‘tests which are appropriate’ were repeatedly exceeded in overzealous efforts to find dietary and environmental carcinogens. The flawed concept remains: any agent which is carcinogenic at high doses is considered to be carcinogenic in minute doses. Interpolation of results obtained with large doses to zero is much less expensive than performing difficult experiments with small or minute doses. Acceptance of small amounts of some proven carcinogens in our food followed discovery of their existence in common foods, e.g., cholesterol, formaldehyde, or nitrostamines, or conviction that it was an essential nutrient, e.g., selenium. Selenium. long known to be poisonous and now accepted as essential, is carcinogenic in high doses and is anticarcinogenic in low doses. (Frost 1972)

"The phrase ‘...tests which are appropriate...’ was indirectly acknowledged by the U.S. Food and Drug Administration (FDA) to the Associated Press (Philadelphia Inquirer May 17, 1989, p.7A) when they rejected the carcinogenicity of bladder implanted chemicals as an index of ingested food additives. Cyclamates were approved 20 years after appropriate tests had been submitted. This precedent should waken both liberal and conservative groups to the possibility that high and low doses of the same agent produce dramatically opposite results. This was inadvertently accepted when FDA beefed up the control group in tests showing red dye #2 was carcinogenic: the mice which had been fed small amounts of the dye, found to be carcinogenic in large doses, were added to the control group to provide increased numbers for better statistics.

"Ames noted that most leading scientists are ‘very skeptical about all these worst case, low-dose extrapolations from high-dose animal tests.’ (1989) He reiterates ‘the dose makes the poison’ and the number of human cancer or birth defects from man-made pesticide residues is close to zero. The same message was proclaimed for all types of carcinogens by Efron; it certainly applies here. (1984, 1989)

"The argument remains that one ray can cause mutation and cancer. In the context of the thousands of cosmic rays and other ionizing rays which pass through each of us every minute, the great repair powers of each cell and the greater recuperative powers of the integrated whole organism make this a very remote possibility. The evidence shows the opposite. Low doses of whole body irradiation activate repair and immune responses with the result that there are fewer cancer deaths in lightly exposed individuals than in controls. This is repeatedly noted in reports with doses <0.2 Gy or levels <1 cGy/d, a level about 1000 times mean natural background exposure of adults in the U.S.

"The literature suggests that mutations as well as cancer have thresholds and generally exhibit hormesis. (Mulholland 1984) Whole-body exposure to low doses of ionizing radiation activates repair systems which allow fewer, not more, mutations and cancers.

"Radiobiologists have not seriously addressed the problem of hormesis in radiation mutation with challenge experiments. The results from cells in culture suggest this is a viable avenue."