The Effects of Low and Very Low Doses of Ionizing Radiation on Human Health

WONUC (ed) Amsterdam: Elsevier (2000) 539 pp, ISBN: 0-444-50513-x This book presents the proceedings of the First International Symposium organised by the World Council of Nuclear Workers (WONUC) which was held at Versailles, France, on 17 and 18 June, 1999. The book opens with an explanation of just what the World Council of Nuclear Workers is and what its aims are. WONUC was founded in 1996 as an association of the Unions and other organised bodies of the world's nuclear industry workers. It was established because WONUC considers that the nuclear workers are faced by two unusual challenges: • the lack of understanding of the nuclear industry by the general public; • the activities of extremist environmentalist movements whose final aim is to deprive the nuclear workers of their jobs. WONUC is quite forthright about the rights and duties of nuclear workers. In view of the aims of WONUC it is perfectly understandable that one of their main interests should be the effects of low doses of ionising radiation on human health and their organisation of this symposium in 1999 is entirely appropriate. The proceedings start with a short foreword by Maurice Tubiana in which he presents the epidemiological, scientific and regulatory problems that are associated with the health effects of low radiation doses in the 0–500 mSv range. The first section of the book covers the opening address, also by Tubiana, and keynote papers by authors such as Roger Clarke, Albrecht Kellerer, Monica Gustaffsson, Carmel Mothersill, Klaus Trott and Roland Masse. Many of these papers, although not all, are substantial and even though they are written in a philosophical style reviewing the level of knowledge in specific areas relevant to low dose health effects, they contain a large amount of useful information and this is definitely the `meaty' part of the proceedings. However, it is worth noting that some of these keynote papers have also been published elsewhere in the open literature (see, for instance, Radiation and Environmental Biophysics volume 39 (2000) and Journal of Radiological Protection volume 19 (1999)) and this duplication deprives these proceedings of some of their exclusivity. The rest of the book, some 450 pages, covers the topics: `Models and controversies in radiation carcinogenesis'; `Chernobyl effects'; `Radon and mining'; `Natural radiation'; `Low dose risks'; `Molecular biological mechanisms'; `Epidemiological data'; `Effects on thyroid diseases'; `LNT controversies'; `Neutron and x-ray effects' and `Working conditions'. This is a broad range of relevant topics and at first sight the book looks appealing and promises to be informative. However, the papers in these sections, which fall into two categories, those with a philosophical approach and those presenting some scientific results, do not really address any of these topics in either depth or detail. The papers presenting scientific results are, on the whole, disappointing and do not offer any remarkable results or new techniques or developments. One interesting paper in this category which does take a new approach to the low dose problem is that of Duport, `Non-linearity between dose and cancer risk for internally deposited alpha and beta emitters in animals' (page 97), but the paper is, unfortunately, marred by bad editing and/or proof reading. One table in this paper is printed twice, one under the other, and values given in the text differ from values in the tables. In spite of the fact that this is clearly a report of work in progress, such clumsy editing does not give the reader confidence in what is being presented. There are also many other typographical errors scattered throughout the book which is unexpected in material from such a reputable publisher. The papers which take a philosophical approach constitute the greatest disappointment not so much for their content as for their clear prejudices. All these papers argue, rather forcibly, in favour of there being a no-effect threshold dose at low dose and against the concept of linear no-threshold (LNT) dose effects which is currently used in radiological protection regulation. The arguments presented by many of the authors in favour of a threshold dose are often based on the same, previously published material to justify their reasoning, and references to the work of Luckey on radiation hormesis, Cohen on a negative correlation between lung cancer incidence and radon concentration, as well as that on the non-linear relationship of bone cancer incidence in both man and animals from internally deposited alpha emitters, occur with monotonous regularity. It is, of course, not fair to judge papers presented in 1999 with hindsight from 2002 but, even before 1999, there were criticisms of much of this work and indications why the bone cancer incidence induced by internal emitters is non-linear although not necessarily indicative of a threshold. The uncritical, rather dogmatic attitude taken in so many of these articles is most unfortunate. Although many scientists support the linear no-threshold concept used in radiological protection, it is clear that there are neither epidemiological data nor experimental radiation biological data which are accurate enough to resolve the shape of the dose effect relationship in the low dose region and differentiate between the two different concepts. It is also clear that the LNT-based concept of `collective dose' recommended by the ICRP has been abused and needs some modification but the solution of this problem will require open-minded discussion between adherents of both the threshold and the linear no-threshold concepts and will have to be very elegant and intelligently made. The proceedings are very obviously biased towards the idea of a no-effect threshold dose and either WONUC has been misled by the purveyors of this concept or they are already confirmed believers in the concept. It is not difficult to understand that the idea that radiation has no effect at low doses is most attractive for nuclear worker organisations but, in view of the vigorous statement of their aims and intentions, it would have been much better if WONUC had taken a completely independent approach and had organised their meeting so that all sides of this topical and difficult problem of low dose health effects could have been voiced and discussed. Many of the authors of papers in these proceedings will, no doubt, say that other meetings and their proceedings on low dose effects are biased towards the linear no-threshold concept and that, moreover, it is almost impossible for them to participate in such meetings. However, WONUC could have established a series of meetings to provide an open forum for a fair and balanced assessment of the validity of the two different low dose concepts. As it is, it seems likely that WONUC will be identified with the no-effect threshold dose concept from now on and this will not make their stated aims easier to achieve. The title of the book is misleading as these proceedings do not, unfortunately, provide much new data on `the effects of low and very low doses of ionising radiation on human health'.