Low-dose Extrapolation of Radiation-Related Cancer Risk

Draft document: Low-dose Extrapolation of Radiation-Related Cancer Risk
Submitted by Diana P Sidebotham, New England Coalition
Commenting on behalf of the organisation

Kindly accept the following comments on the ICRP Task Group 1 Report, titled "Low-Dose Extrapolation of Radiation-Related Cancer Risk." They are submitted by the New England Coalition (NEC), a public-interest organization in the United States, with a longstanding concern for safety from radiation injury, especially in our northeastern portion of the nation. The primary focus of NEC, during its 34 years, has been oversight of the operation of nuclear power reactors in our region and of the management and isolation of the radioactive wastes they generate. We are pleased with this Report, for the most part, and commend the ICRP's Committee One Task Group and its Corresponding Members who contributed to it. The Report provides clear explanations of the current status of scientific knowledge about radiation exposures and their impacts, including excellent descriptions of recent radiobiology findings in the research at cellular, molecular, and DNA levels. Although it does not appear to have been prepared for consumption by the non-technical general public, much of the text is presented in ways that are readily digested by persons with interest and concern or regulatory responsibility, even if they may lack advanced training in the science. We are supportive of the Task Force's conclusion that the linear dose-response (LNT) hypothesis is valid and should be retained in radiation protection. We appreciate the Report's conclusion that no threshold dose level should be recognized. We concur that far more research is required in order to understand fully the biologic effects of low doses that are far lower than c.10 rad per year. We are encouraged that the authors recognize the limitations of present-day understanding of the impacts of both very low doses and protracted low-level exposures upon recipients. The approach is quite conservative, and is refreshingly unlike the dismissiveness toward public concerns that is expressed too often by health physicists and others who are entrusted with protection of the health and safety of the public, nuclear industry workers -- and the environment. It is hoped that the full Commission will adopt the tone and substance of this report in the course of revision of the ICRP-2005 Recommendations, on which we had commented in December 2004. The ICRP-2005 seemed to be a reversal of all the research gains of the last twenty years, retreating back to a pre-BEIR V position, by reviving the discredited notion of a "safe threshold" below which it was claimed that there is no threat of biological injury. This Report, instead, advances in the far safer direction of supporting what is now known, and specifying what remains to be understood, about low-level radiation impacts. NEC respectfully offers a few observations and suggestions. 1. The thrust of the Report is that low-level radiation exposures may indeed in many, if not all, instances result in a health hazard for recipients. Yet the research data described appear to be based on doses that we would not consider to be truly "low." Recognition of this fact is expressed in the cautions expressed throughout the Report. The cautions, in the face of current lack of research with sound data at very low radiation levels, should be acted upon by the ICRP with outright rejection of any proposals to allow exclusion from regulatory control at 1 mSv/year dose level -- or even at a 1 mrem/yr level. ICRP recommendations should not be corrupted by taking into account the costs associated with both short- and long-term protection. Those are unavoidable costs associated with using nuclear energy and they must be absorbed by the generators and other licensees as their normal costs of doing business. Any other allocation of costs associated with protection (such as failing to control potential exposures) is a transfer of the burden to the public, to workers, or to future populations. 2. The Report seems based on an expectation that the purpose of the Commission is indeed protection of human health and safety -- and, we hope, in the near future also of other forms of life, as ICRP has recently proposed to review. For those reasons, we urge that the Commission recommend against further use of risk analysis in formulation of ICRP recommendations. It is an individual who is in need of protection. But risk analysis is based on consideration of certain impacts upon whole populations and then placement of an individual within the population, not based on the impacts on that individual who is unique in his or her characteristics and responses. Instead, recommendations do need to be based not on central tendencies, or on abilities of those most capable of resisting negative impacts of radiation exposures, but rather on individuals who comprise the most sensitive sectors of populations, those who are in greatest need of the fullest protection. "Risk" is a thoroughly subjective matter, differing perceptually greatly from person to person, situation to situation, time to time, and unique to each individual. Use of risk analysis as a legitimate basis for protection is antithetical to the very purpose of protection of people. 3. In the same vein, public-interest advocates of many varieties are frequently heard to plead for adoption by regulatory decisionmakers of the so-called Precautionary Principle. We earnestly join that plea. So long as doubt remains about the safety of one's recommendation, the ethical action is not to proceed, stumbling irreversibly into an unknown, but, rather, to exercise caution, warn of the limits of understanding, and refrain from causing damage. First, to do no harm. 4. Related to caution is burden of proof. A commission on protection must also recognize that, in law as well as in other venues, traditionally the burden of proof resides with the victim, with respect to damages caused by external factors, often long delayed in manifesting an injury, and difficult or impossible to affix to the original causation. The history of radiation injuries exhibits this factor, with those experiencing symptoms of illness or other damage that lie outside the canon of the decisionmakers being ignored, ridiculed, or simply dismissed with no rightful compensation or assistance provided. We want to hope that this particular Report will go far to rectify those past wrongs. 5. As the recent microbiological research, described so compellingly in Chapter 4, has now confirmed, irradiation at low doses is observed to cause damages to cells, molecules, and DNA, resulting in mutations, or imperfect repairs, that may persist into future generations. One could liken our current imperfect protection as a stumbling into a genetic darkness of an unknown biological future that we seem only now to be beginning to comprehend and confirm. Therefore, we strongly urge the Commission to apply this Report in support of recommendations for far more research in the realm of transgenerational mutational consequences of low-level radiation. 6. As important as are cancers, a leading cause of devastating illness and premature death, far more attention is needed to identification of other illnesses, disorders and life-disrupting effects resultant from or associated with low radiation dose levels. More attention is also needed to the range of repairs and consequences of imperfect repairs, with a hope that constructive repair mechanisms can be developed -- but not as a justification for allowing a preponderance of irrepairable injuries to be permitted. In sum, it is a pleasure to comment positively on this document. It deserves incorporation into all future ICRP recommendations and broad circulation among the general public and especially those charged with radiation protection decisions. Thank you for the opportunity to submit our thoughts to the Commission.