... but critics still uneasy on medical grounds

Press, 4 December 1985, Page 21

... but critics still uneasy on medical grounds

Although the general attitude of Government scientists is that there is no evidence that microwaves and other low-level electromagnetic radiation are harmful, there is still some public unease and suspicion that certain ailments and conditions could be caused by them. After all, scientists have proved each other wrong before now. The difficulty is in excluding all other possible causes of such effects. The vast amount of research being done world wide into the effects of low-level radiation on organisms shows that the scientific world is by no means satisfied that low-level non-ionising radiation has no harmful effects. .

Some of the research shows that, effects do occur at very particular frequencies, and perhaps not at others. Another strange observation is that although there may appear to be no direct effect caused by the radiation, subsequent stress of an entirely different kind can somehow trigger a reaction for which the radiation has predisposed the organism. In the A.B.C. documentary, “Air Wave Warning,” Dr Ross Adey, associate chief of staff for research at the Veterans Administration Hospital at Loma Linda, California, said that laboratory experiments showed a connection between a high incidence of leukemia and exposure. to weak electromagnetic

fields. He said young tissues and embryonic tissues appeared more susceptible, and questioned whether children should play under high voltage power lines. Dr Adey said he was deeply concerned that the effects of different field exposures, at work and at home, could be cumulative. The same expert was one of seven “outstanding researchers” assembled by the Bioelectromagnetics Society in Boulder, Colorado, last year to examine new findings that link changes in organisms to irradiation by weak fields. A report of the discussion in the scientific journal "Spectrum” noted that in the last three years'the study of biological effects of radio

frequency electromagnetic fields had taken a new turn. A growing mass of evidence had virtually ended the debate as to whether all effects on organisms were caused simply by heating; few now questioned that some weak-field effects existed. Weak fields are those that cannot cause heating in animals outside the animal’s normal temperature range, and are generally power densities of one milliwatt per square centimetre or less. Effects observed in experimental animals and biological preparations have ranged from subtle changes in body chemistry to possible gross deformations of feotuses. , , r. ' ;

The report said the most dramatic findings discussed by the panel were those indicating that microwaves may, in some circumstances, induce chromosomal damage in live animals. Male mice were exposed to microwaves at eight times less than the recommended safe limit for humans, and the damage to their chromosomes, and those of their offspring, was also observed in experiments by other laboratories. Dr P. A. Czerski, a United States Public Health Services researcher, cautioned that the results could not at present be generalised to other frequencies dr to humans, but $ added that chromosomal defects are quite serious. A common ?

human ailment that may result from such defects is Down’s Syndrome, in which the victim suffers mental retardation and a reduced life expectancy. Other researchers found related results when midge larvae and yeast were subjected to weak field radiation. A possible explanation for the effects is that the genetic material resonantly absorbs the radiation — that is, the genetic material has natural periods of oscillation close to the frequency of the imposed electromagnetic fields. Another aspect of electromagnetic radiation which has been known since the 1970 s is its effects on the nervous system and the .« immune systems of animals. v

Dr Adey told the panel that the flow of calcium ions from the brain cells of various animals can be changed by exposure to microwave radiation modulated at extremely low frequencies, and by the extremely low-frequency fields themselves. “It is known from previous research that calcium ions play a critical role in controlling the electrical pulses generated in nerve-cell membranes, pulses that are important in carrying information in the nervous system,” said “Spectrum?’ It added that this finding is viewed as one of the most solid pieces of evidence that effects because : the results have -‘ been duplicated in other laboratories. Dr Adey says extremely low frequency fields can definitely change cell functioning. Experiments showed that they could increase the excitability of nerve cells (the rate at which they produce nerve putse); reduce by as much as 20 per cent -the killing capacity of mouse T-lymphocytes (the cells that kill foreign or cancerous cells in the bloodstream); and reduce insulin production in pancreas cells by 35 per cent. Other experiments with rats showed changes to the lymphocytes and the adrenal glands, but the work is being repeated with more animals, and if the effect is confirmed, further studies will be done

to see if the increase in lymphocytes could affect the rats’ ability to combat viruses and tumours. In the case of extremely low frequency fields, such as those around power lines, experiments with miniature swine showed that such fields can induce defects in the offspring — 75 per cent of the exposed pigs’ litters had deformed piglets, against 29 per cent for the controls. Because of some puzzling aspects, a follow-up experiment involving more pigs is now planned. Similar experiments on rats produced ambiguous results, and a large experiment on chicken eggs yielded negative results. Methods-of-measuring safe ‘dosage were als6': questioned by -the Bioelectromagnetics Society panel. “With the accumulation/ of new data, the idea is gaining that what is critical is the total; absorbed energy — the power times the duration — as is the case with ionising radiation,” says the journal. “The new Soviet Union standard for occupational exposure, revised in 1982, is based on just such a notion of a constant asborbed energy level per unit mass.” Soviet studies showed that an organism can compensate for many effects of electromagnetic fields, but becomes in if stressed subsequently. “In other words, the fields are an added burden that, if imposed on an already weakened animal, can cause breakdowns.”