2005 ICRP Recommendation

Draft document: 2005 ICRP Recommendation
Submitted by Hans Vanmarcke, Belgian Society for Radiation Protection
Commenting on behalf of the organisation

SECRETARIAT COMMENT: the length of the comment exceeds the available size, therefore the comment is split into 2 parts. Comments of the Belgian Society for Radiation Protection (BVS-ABR) PART 1 OF 2: Introduction The Belgian Society for Radiation Protection (BVS-ABR) welcomes again the opportunity given by the ICRP to its stakeholders to comment on its proposals before these are published as new recommendations. As a result of the publication of the draft text, mid-2004, the Belgian Society for Radiation Protection has set up his working group to analyse and comment the text and to make, where applicable, suggestions to further improve the ICRP proposals. The Belgian Society for Radiation Protection hopes that these comments and suggestions will be taken into account in the further elaboration of the ICRP recommendations. Anyway, the working group is open for further discussions on this topic. 1 About the system of protection in general (chapters 2 and 5) [11] In general, the working group fully agrees that an effort had to be made to simplify and consolidate the actual system of radiation protection. The proposals that are made to give a new structure to the protection system could open the door in this way. Nevertheless the working group believes that the new recommendations, as written in the draft text in it present form, are still too vague. As there is moreover an attempt to be more distanciated from the scientific bases, one could fear the lack of credibility that will be given on such a text within the radiation protection world. Suggestion: - define more explicitly in the text what is recommended by the ICRP (besides what are only statements or considerations). [12] ICRP increases the soft law content of regulations and ICRP is directing regulations more towards Anglo Saxon common law than to Continental Civil Law legal orders. This new recommendations are less prescriptive on the level of law and will allow more space to judges and negotiations among lawyers. Clarification of concepts as justification, optimisation and quality assurance in radiation protection can help develop a more precautionary approach. [13] At different levels ICRP refers to a virtual average individual, while each individual is a legal subject for regulatory purposes. ICRP is not enough considering the most vulnerable individuals and groups and is not as such respecting individual rights. What fraction of individuals is susceptible to ionising radiation? How important is the risk for such subpopulations? Are humans predisposed for radiation induced specific malformations in the pre-implant period as animal experiments seem to indicate? It is no longer for sure that society and the common good is enough protected if "the" individual is protected. [14] In the same way, the Commission indicates in paragraph (6) “a move from the utilitarian approach of “the greatest good for the greatest number”, to one with more concern for the “individual””. The intent to provide a level of protection for the most exposed individuals within a class of exposure is confirmed in section 6.3 “Application of the dose constraints”. On the other hand (paragraph 80) “the Commission has previously made a policy decision that there should be only one single set of wT values that are averaged over both genders and all ages. The Commission continues to maintain that policy in these Recommendations”. The working group would like to bring to the attention of the ICRP that these two positions or statements are apparently contradictory. 2 About the justification concept (chapters 2 and 9) [21] Although justification remains present in the draft recommendations, it is fading very explicitly as one of the pillars of the system of radiological protection. The scope of the recommendations is being limited to exposures that have preliminary been deemed justified by Governments or Governmental Agencies. Only for medical exposures, the draft recommendations explicitly mention a 2-fold justification as part of the system of radiological protection: a generic justification of the practice, that is supposed to be performed by the medical profession (19) or the national professional bodies (218), and an individual justification for each patient, that is to be performed by the prescribing physician and the practitioner (219). [22] Despite the fact that the working group strongly advocates for keeping justification as the most important pillar of radiological protection, it does recognise the fact that Governments or Governmental Agencies play a very crucial role in the process of generic justification of a practice. However, the working group feels that it is not correct to transfer the complete responsibility of the fundamental process of justification explicitly to Governments and politicians, as this may result in the complete omission of the process during licensing or other activities related to the radiation protection management. [23] Furthermore the working group does not understand the Commission’s motivation for making an explicit difference between medical and other exposures in relation to justification. For both medical and professional exposures a clear distinction needs to be made between the generic and a particular justification and the nuclear industry holds many examples of particular exposures that were judged not justified although the production of nuclear energy is generically justified. [24] Additionally, the working group feels that it is ethically unacceptable to give the responsibility of the generic justification of medical exposure solely to the medical profession. According to the working group, there exists no clear motivation to exclude explicitly the health physics professionals, the Government and the other stakeholders from contributing to the generic justification of medical exposures. Suggestions: - reformulate (18) in order to highlight that justification of particular exposures are also in the field of non-medical exposure of primary concern for protecting the exposed individuals, hence explicitly re-instating the justification of an exposure as the primary pillar of radiological protection; - rethink the explicit transfer of responsibility for the generic justification of non-medical exposures to the Government and of medical exposures to the medical profession solely; - formulate clear and comprehensive guidance on the practical realisation of the justification of exposures to ionising radiation. 3 About the dose limits and dose constraints (chapter 6) [31] It is stated in paragraph (157) “the Commission considers that the annual effective dose from natural radiation sources, and its variation from place to place, is of relevance in deciding the levels of maximum constraints that it now recommends”. As a result, there are no more scientific bases for the recommended dose constraints, which are based on “natural values” and not on risk estimates. Even if this choice may perhaps facilitate public acceptance, the recommended dose constraints lose their scientific bases for the experts. The working group believes that the presentation of the bases for the recommended dose constraints could be re-considered, in a way that also rely on a scientific basis. This could increase the credibility of the approach (see also comment [11]. [32] Moreover the legal enforcement capacity is weakened due to the change in hierarchy in the principles of the dose limitation system. Justification fades away while constraints, earlier only a tool for optimisation came on top followed by optimisation based on a matrix, which is difficult to consider in legal terms. The justification of a reference dose, such as background, relates to the difference between acceptable risk and negligible dose. They differ in terms of impact on individual rights, collective health and environment (disaggregation). A social justification is needed at actor's level, supported by collective risk management, taking individual rights into account. In that case even higher doses could be accepted. However a concept cannot be a generic foundation for a dose limitation system. 4 About the optimisation principle (chapter 7) [41] In the introduction of the recommendation, under (10) it is stated that “ …ionising radiation … needs to be treated with care rather than fear and its risks should be kept in perspective, both with the benefits of its uses as with other risks”. One could expect that this essential statement would be further developed in the recommendations, especially in the chapter concerning the optimisation. The paragraph 7.1 of this chapter, the “characterisation of the optimisation process”, contains some general statements on how optimisation should be realised, but remains very abstract. The paragraph 7.2 with the “dose matrix” is more explicit, but is only focussed on the discussion about the integration of collective doses over time and space. One should be aware that for people dealing with radiation protection ‘in the field’, the outcome of the rather theoretical discussion on the integration of doses has only a limited added value. On the contrary, they would like to be guided in their more practical concerns on how to proceed in their daily effort to optimise exposures. In this way it is also interesting that attention is kept on the advantages of making optimisation coherent with the actual safety management techniques, with as example the internationally applied standards ISO14001 (environmental management system, that can integrate the optimisation of public and environmental exposures) and OHSAS18001 (safety management system, that can integrate occupational exposures). These management techniques are moreover focussed on involvement (communication, participation). The first advantage of a ‘combined’ management of radiation and other safety risks is the saving of resources. The radiation protection has not to ‘re-invent the wheel’. There are a lot of synergies possible in the efforts to reduce or prevent risks. But a second advantage of a combined approach is the contribution to the demystification of radiation risks, as the risks are inherently kept in perspective with other risks. Suggestion: - describe, at least as a guideline, a formal methodology to be followed for the optimisation. The methodology could refer to well implemented safety and quality management techniques. 5 About the biological aspects (chapter 4) [51] The Commission presents in its draft recommendations a new estimate for genetic risk of 0.2% per Gy (108), which is considerable lower than the risk factors that were given in its Publication 60. Although it is clearly mentioned in (108) that the given value takes only into account the risk up to the second generation, the working group feels that there is not sufficiently attention drawn to this significant change in the evaluation method. Furthermore, the working group judges the introduced restriction of the evaluation period to only 2 generations not scientifically acceptable as it is known from animal experiments that manifestation of most genetic effects requires integration over a larger number of generations. [52] In (119)-(122), the Commission describes the problems related to the genetic susceptibility to cancer for which the Commission clearly recognises the progress that has been made since 1990 in the knowledge of the human genetic disorders in relation with an increased sensitivity to the carcinogenetic properties of ionising radiation. However, the Commission concludes that the information that is currently available is insufficient to provide a meaningful judgement. Although the working group recognises that the current status of the available data makes it too early to present sound quantitative recommendations based thereon, the working group thinks that the effects observed in rodents and in cultured human cells should warrant at least a recommendation of caution from the Commission, especially given the fact that effects have been noted after in-utero exposure of genetically predestined individuals to doses of the same order of magnitude of standard medical exposures. An analogue remark hence has to be made with respect to (118) treating the radiation effects of in-utero exposure. The working group does not understand how the Commission can declare that prolonged doses well below 100 mSv for in-utero exposure do not form a specific protection case, whereas it considers an annual dose limit of 20 mSv for adult workers. [53] In paragraphs (123)-(125) the Commission treats the occurrence of non-cancer diseases after irradiation. Although the statistical evidence was strengthened for the occurrence of heart disease, stroke, digestive disorder and respiratory disease, in relation with exposure to ionising radiation, there still exists an important uncertainty with respect to the shape of the dose-response at low doses. A consistency with both no threshold and a threshold of around 500 mSv is observed. From this, the Commission decides not to include these effects in the estimation of the detriment following doses of a few tens of mSv. The working group would like to underline that this situation is not that much different than for radiation-induced cancer: a known dose-response curve at high doses and an unclear situation in the region of a few tens of mSv, both compatible with no threshold or with a certain threshold. Although the working group acknowledges the fact that the maximal possible threshold for cancer induction today is significantly lower than the 500 mSv mentioned for the induction of non-cancer diseases, the working group recalls that this situation did not discourage the Commission several decades ago to adopt the LNT-hypothesis, which it still endorses today. [54] Paragraph (109) mentions only mini satellites, not micro satellites (which may give rise to disorders). Suggestions: - re-evaluate the fact that the genetic risk factors presented are only valid up to the second generation or at least draw sufficient attention to this fact; - include a warning with respect to possible effects in genetically predestined individuals; - re-evaluate the phrase stating that for in-utero exposures well below 100 mSv no special protection measures are necessary; - have a more precautionary approach related to non-cancer effects; - take also micro satellites into consideration under paragraph (109). THE COMMENT CONTINUES IN A SECOND PART