Is radiation really so dangerous?

Now here's something to sow despondency in the heart of any television producer working in consumer affairs: a programme with the nerve to suggest that something we had all been told was extremely nasty might not be quite so bad after all.

Despite its alarmingly let's-scare-them title, Nuclear Nightmares was not a consumer affairs production. It was an edition of Horizon that set out to do precisely what a good science programme should: to question the evidential basis of a widespread fear of technology. The issue was our acute nervousness about radioactivity; the question was whether low doses of radiation are as damaging as popularly believed. The answer is important because, at a time when we are contemplating how best to put the brakes on global climate change, invalid assessments of the risk inherent in nuclear power could seriously distort future energy policy.

The programme recounted the events at Chernobyl. It did so in part through the eyes of one former inhabitant returning to her old apartment. It also explained how the experiences of Hiroshima survivors had been used to calculate health risk in relation to dose received: a curve that, by extrapolation, has since been used to predict the harm resulting from much lower levels of exposure.

The thrust of the case in Nuclear Nightmares was that the number of deaths attributable to the radiation released from Chernobyl has proved to be only a fraction of the 9000 predicted. In 2005, some 20 years after the accident, the Chernobyl Forum—a body made up of governments and United Nations agencies—concluded that fewer than 60 deaths had actually occurred. And most of these had been among the highly exposed clean-up workers.

Other evidence used to question current risk estimates included the experience of airline personnel; despite spending large chunks of their working life at an altitude that exposes them to higher levels of cosmic rays, they do not apparently show the predicted excess of cancer or birth defects. Research on the wildlife that has thrived in the Chernobyl exclusion zone tells a similar story: there's little evidence of the expected damage to its genetic material.

Figure 1.

The programme claimed the number of deaths caused by radiation from Chernobyl has been far fewer than predicted

Credit: V IVLEVA/FOCUS/REX

In referring to the events at Hiroshima and Nagasaki the programme could also have pointed out—though for some reason it didn't—how studies of A bomb survivors and their children have already revealed that the long term effects of radiation are much less than expected. The Atomic Bomb Casualty Commission—now the Radiation Effects Research Foundation (RERF)—has had this to say on the health of the children of adults who survived the blast: “To date there has been no evidence of increased risk of death from cancer or other causes nor of incidence of cancer. In particular, mortality during childhood...was not related to parental radiation exposure” (www.rerf.or.jp/eigo/radefx/genetics/mortalit.htm).

Despite the importance of understanding the effects of radiation, the painstaking work of the RERF must be among the least publicised of all long term scientific endeavours. Indeed, in the last decade of the 20th century, the project was nearly abandoned for lack of funds. Its problems may have stemmed from its failure to say what people expected to hear. Maybe even what they wanted to hear. The latter is certainly true in the case of Chernobyl. The findings of the Chernobyl Forum have generated a deal of controversy. Not least among the critical voices have been those of green campaigners for whom any possibility of nuclear power being less than the devil's work are not to be entertained.

Maybe, the programme suggested, the effects of radiation at low doses cannot be predicted simply by extrapolating the risk versus dose curve. Contrary to the assumption that has prevailed until now, maybe there is a threshold below which it causes us little net damage. It is just possible that the curve could be j shaped, with a small amount of radiation being good for us. Shades here of the argument about the benefits of alcohol.

There is even a plausible basis for some kind of threshold effect: that radiation stimulates protective genes to greater activity, which, up to a certain level, keeps the damage in check. In the end, though, the programme made no attempt to push the argument too far. Its writer and producer, Nick Davidson, simply raised the question of whether we have become what he describes as irrationally “radiophobic.”

Over the past decade, the issue of global warming and how to deal with it has moved centre stage in public consciousness. If this looming disaster is only half as threatening as it has begun to appear, to rule out even one remedy of the several that might be used to contain it is perverse. Maybe Nuclear Nightmares will help prompt a rethink among the sizeable part of our community who view any solution involving nuclear power as worse than the problem it is designed to tackle.