2003 Recommendations of
2.2 Basis of the report
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The Health Effects of Ionising Radiation Exposure at Low Doses and Low Dose Rates for Radiation Protection Purposes:
Chapter 2: Basis and Scope of the Report
The European Committee on Radiation Risk arose from a recognition among scientists, politicians and campaigners that there was considerable disagreement over the health effects of low-level radiation and the feeling that this issue should be explored on a formal level. The committee's remit was to consider all the available scientific evidence. In particular, the committee was to make no assumptions whatever about preceding science and to remain independent from the previous risk assessment committees such as the International Commission on Radiological Protection (ICRP), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the European Commission and risk agencies in any EU member State. The committee believes that in the search for scientific objectivity it should 'look out of the window', rather than following the trend of increasing dependence on processes of mathematical modelling. Thus the committee has considered the results of studies published in the peer-review literature and also reports, books and articles which have not been submitted for peer review. The committee believes that the approach adopted by scientific risk committees of only accommodating evidence with accurate dose-response data published in peer review scientific journals has resulted in the propagation of a model which is increasingly seen to be unsafe. Furthermore, the committee believes that discussions in the area of radiation risk must involve all groups in Society. Therefore, although primarily consisting of scientists, the committee and its advisors include those physicians, non-scientists who must deal with medical problems of exposed persons. For example, risk assessment should include physicians trained in Public Health, Occupational Health Oncology, Paediatrics, and scientists trained in Genetics, Epidemiology and Biochemistry. These disciplines are not represented in the Main Committee of the ICRP. The regulations on membership as posted by ICRP includes: physicists, medical regulators, radiologists, biophysicists, etc. Persons who do not use radioactive materials in their employment are excluded. Among those included as advisors to the ECRR would be non-scientists such as risk sociologists, lawyers, politicians and members of non-governmental organisations and pressure groups.
The present report is intended to be accessible to and to inform decision makers who need to assess health risks to workers and members of the public who may be exposed as a result of practices which involve ionising radiation. It is therefore labelled a 'Regulators' Edition', the aim being to condense or review enough of the area for this process to be possible without being unwieldy. Future publications will deal in depth with the issues outlined here. The basis of the report is a perceived failure of the present radiation risk model (named here the ICRP model) to explain or predict real increases in ill health in a large number of groups exposed to ionising radiation at low doses. Most of the examples where this has occurred will be referred to in the body of the report but the position of the committee has been affected also by much that cannot be included, for reasons of space. This includes reports which have been published in the peer-review literature, and reports which have not, or which started life as television documentaries and ended as court cases. The committee has included consideration of those who voted with their feet and left areas where there were nuclear sites, regions which slowly became wastelands where only the poorest people could live and where the beaches were deserted by holidaymakers and fish were increasingly difficult either to catch or sell. It has included the tales of ordinary people who have been affected by man-made radioactivity, in India, Namibia, Kazakhstan, Nevada, Australia, Belarus and the Pacific Islands. For those who are prepared to read contemporary reports there are enough desperate stories. One example is that of weapons tests and the Australian Aboriginal people who were found dead in contaminated craters. Another concerns whole tribes in the Marshall Islands who had to abandon the Islands which they had called home for 3000 years.
The report will review the present methodology for assessing radiation risk. It will argue that its dependence on averaging, both in the area of energy deposition in tissue in space and time and also its dependence on epidemiological studies involving external exposure has resulted in major errors in its quantification of risk from internal irradiation. It is intended that the report should convey sufficient evidence that the present radiological safety models are largely accurate for external irradiation situations involving doses greater than 100 mSv but break down where calculations involving averaging methods are used to examine non-uniform doses in microscopic tissue volumes. The report will examine the historical origin of the ICRP model and will review epidemiological evidence for its successes and failures. The report will consider the philosophical aspects of the science of radiation risk and make a distinction between the inductive and deductive approaches to establishing objective risk estimates. It will present evidence for quantitative ranges of error in the ICRP models as highlighted by various authors and studies and will assemble these into a set of hazard enhancement weighting factors which form the basis of a pragmatic interim approach to the problem of assessing radiation risk using the present units and quantities. Finally, the report will briefly outline some examples of the application of such a system for assessing radiation risk. A calculation of the mortality yield of the post-war nuclear age based upon ICRP and modified ICRP risk factors will also be presented. The approach is necessarily pragmatic. Data on radiation exposures and activities has been tabulated and recorded using units of dose devised from within the ICRP system: it is therefore necessary to provide factors which may be used with this system and this is what the committee has striven to achieve. These factors are provided as central estimates of hazard enhancement for certain types of exposure and may be used as multipliers of risk for the risk factors presently used by ICRP. However, the committee believes that the use of the average energy dose units Gray and Sievert places too many constraints on the science of risk assessment for internal isotopes and that a different, more rational system of assessing such exposures is required. Some suggestions are made towards achieving such a system.
The committee carefully considered the question of whether the editors should attempt to reference every statement made in this Regulators' Edition. On the one hand, the ICRP, whose handbook ICRP90 this present volume is intended to supplant, contains no references. On the other hand, the more lengthy reviews of the United Nations (UNSCEAR) and the US Academy of Sciences (BEIR) carry select references which support their statements whilst omitting other references to work which either falsifies or does not support their statements. In addition, the committee was aware both of the constraints that would be placed on the size of the edition if all statements were referenced, and the loss of flow of the argument which would follow the considerable expansion of the text. As a compromise, the committee decided to attach a list of the main works on which its beliefs are founded, without attaching each to some piece of the text. In addition, certain references are included where it seems particularly necessary to draw attention to a particular source.
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2.2 Basis of the report
Scope of the report
Link to Executive Summary
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