The theory that's coming in from the cold

Editorial from Radioactive Times Volume 4, Number 1, June 2000 (content not updated)

We welcome publication of NRPB's version of Busby's Second Event theory in the International Journal of Radiation Biology [see report in this issue] and hope it will open up further debate, including among those who might reasonably be described as anti-nuclear, but who tend to remain deaf to anything rejected by the review system's frequently partisan gatekeepers.

The fact that the Second Event theory was excluded from the scientific literature for so long is evidence of the remarkable rigidities of the peer review system: the fact that NRPB have been obliged to take it seriously enough to put it through their logic mincers and publish it in their own Journal is a tribute to what many have felt about this proposed mechanism of genetic damage from very low dose radiation - that it is sufficiently robust and plausible ("obvious", even) to warrant further investigation.

But NRPB have, despite having to deal with biological interactions in living systems, confined their argument to mathematical models. This will not do; the question of who is right - Busby or the NRPB - can only be settled by experiment. It is no trivial matter, for the theory undermines the very foundation of radiation protection and, consequently, any justification for nuclear power, reprocessing, and nuclear weapons.

We already have it on very good authority that the theory is eminently capable of being tested empirically, but such experiments are beyond the limit of what NGOs can be expected to do, even in the interests of public health. Where is the political will to do them at public expense? Not in NRPB, we feel.

NRPB's Director, Roger Clarke, is also Chairman of ICRP. He thus occupies a pivotal position in this particular area of risk management (or perhaps we should say "area of managing risk peception"). It is a sociologically interesting landscape: on one side stands a public which distrusts anything nuclear and the many scientists who say "the effects of low level radiation are far worse than ICRP thinks". On the other side the nuclear establishment would be delighted if there were a threshold below which no harm was done. On the fringe, the hormesis peddlars claim that "a little radiation actually does you good". In no man's land the medical establishment vacillates, concerned at the associations between radioactivity and the steady increase in cancer rates, but at the same time dazzled by new techniques of nuclear medicine and committed to x-ray diagnostics and cancer screening.

Clarke's response? - a contradictory and essentially political fudge.

Writing in the Journal of Radiation Protection Clarke proposes a new regime based on the existing Linear No Threshold (or "no safe dose") model. He thus seems to steer a moderate course, but at the same time he clings to the conventional idea that natural background radiation and man-made isotopes confer similar risks, and argues that if the public could be made to understand radiation risk in terms of multiples or fractions of natural background there might be "no need to destroy the credibility of the (radiation protection) profession in arguments for or against a threshold." This is not science, it is politics. Clarke abandons hope that experimental research could prove or disprove the existence of a low dose threshold, and believes that epidemiology is incapable of doing so. But in what he calls "the continuing lack of definitive scientific evidence" he proposes a new approach which dumps the concept of Collective dose. This is important. If LNT applies, the lowest doses of radiation can cause genetic mutation, so there is a need to add up the doses (the "Collective dose") to large populations, including those yet unborn.

Clarke's proposal is schizophrenic - to keep the "no threshold" model but set an arbitrary epidemiological threshold consisting of the limit of what can be demonstrated by such epidemiological studies as the establishment admits, limited and often dubious though they are.

One prominent hormesis peddlar recommends that his colleagues "should (perhaps a little reluctantly) support Roger Clarke's small step into the right direction." Opponents of nuclear power have reacted variously, with outrage at Clarke's barefaced politicking and lack of logic, and amusement at what they see as his hopeless effrontery. It is unwise to assume that his ideas are too crazy to make any headway. They fit well with the IAEA's long-term "Below Regulatory Concern" strategy of writing off low concentrations of pollution, and they were scheduled for extensive dicussion by the International Radiation Protection Association congress in Hiroshima in May, and by ICRP in the autumn of 2000.

ICRP says that it wishes them to be discussed. We should make sure that they receive many representations.