A critical review of the draft 2005 ICRP Recommendations
Luxembourg 4 November 2004
Meaning of this document
This document presents in brief the highlights of the EU Conference on 4 November 2004 dedicated to the critical review of the draft 2005 ICRP Recommendations. These highlights have to be regarded as major and pertinent issues that were discussed during the Conference.
This document is not intended to give an exhaustive list of all the issues brought up during this Conference.
The highlights have been identified by the RIHSS (Research Implications on Health Safety Standards) Working Party of the Article 31 Group of Experts after the Conference. The Article 31 Group of Experts recommended the Commission to submit this document to ICRP for consideration.
- There was concern about the new risk coefficient for radiation induced hereditary diseases.
Reasons for concern:
– When evaluated on comparable bases (risk for the first generation, for 2 generations, …) , the genetic risk is not reduced in the UNSCEAR 2001 Report by comparison with the UNSCEAR 1993 Report. Nevertheless, based on the existence of large uncertainties, ICRP takes now the effect on the generations farther than the second as being zero. Can this decision be considered as a balanced acceptable position according to the present scientific knowledge?
– According to the challenging speaker, the main problem is the radiation induction of small deletions leading to recessive mutations and diseases of which the phenotypes might frequently not be recognized by the physicians. Such cumulative small genetic disorders may propagate in the future generations with the risk of leading to more important pathological consequences. This is hardly taken into account by ICRP (and UNSCEAR) in the risk coefficient, as they are of the opinion that the major contribution to the genetic risk comes from large deletions expressing themselves essentially in the first generations. The basic question is whether we know enough about the radiation induced hereditary effects to close the matter.
- Are the persisting uncertainties and the new experimental evidences in the field of the effects of in utero exposure (exposure of zygotes, genetic susceptibility to congenital malformations, subtle IQ effects, ….) sufficiently emphasized and taken into account in the draft 2005 ICRP recommendations? In particular, the reduced attention for the protection of pregnant women, for instance in the section concerning the medical exposures, has been challenged.
- Other issues are:
– Is a value of 2 for the DDREF in high dose rate exposures (incl. medical) warranted?
– The differences due to age and gender are not appropriately taken into account. In particular, the use of specific wT to calculate the effective dose should be discussed.
- The limitations in the scope and the use of effective dose are not sufficiently underlined.
- Uncertainties may be significant in internal exposures. Currently these are hardly mentioned and taken into account.
- The introduction of organ/tissue dose constraints or limits should be considered and evaluated as regards their practical application. The reason is that effective dose does not reflect the actual risk and health consequences in all situations.
- The introduction of specific wR for low-energy electrons should be considered, as for tritium and Auger electrons.
Issues regarding the system of dose limitation
- ICRP should consider confirming strongly the current three-principle system, without fading out any principle, in particular as regards the justification principle.
- The rationale/coherence/justification of the proposed scale/values for dose constraints (with situations to which they apply) have been challenged and should be carefully reassessed. The « reference to background » approach is mainly useful for public communication. The fundamental input should remain a risk based approach.
- The method that will be chosen to define reference groups or « representative individuals » should take into consideration the principle of equity for the real (legal) individuals.
Issues regarding the proposed system of exclusion levels
- The principle of exclusion levels for artificial radionuclides was strongly challenged. Are such exclusion levels justified?
- Exclusion levels for natural radionuclides should be reassessed carefully as the currently proposed values may lead in some particular situations to very high exposures.
Ethical and legal issues
- Some of the issues mentioned above relate to ethical considerations: management of uncertainty, responsibility, precaution, equity, ….. The value judgments made by ICRP have been challenged.
- Are individuals really better protected with the new recommendations? Paradoxally, despite claiming that more attention is now given to the protection of individuals, the new ICRP recommendations could be considered as globally decreasing individual protection because of:
o new priorities in the three-principle system of dose limitation
o very large scale of numerical values for the dose constraints
o insufficiency of precautionary approach in some fields
o new approach of collective dose
o limited consideration of genetic susceptibilities even in high doses situations
o introduction of exclusion levels,…
- Although ICRP is not supposed to write regulatory texts, it should be aware that there could be legal enforcement problems with its new recommendations in the EU (common v/ civil law systems). This could undermine their acceptability.
- Is the environment really protected with the proposed approach? ICRP should continue working on the development of a more efficient system of protection of the environment, clearly involving stakeholders.
- Are the reasons to modify the current system sufficient? In particular, will radiological protection really be improved with the new recommendations? If so, these reasons or potential improvements should be clearly explained and developed, taking into account the issues that were raised during this Conference.
- Moreover, continuity between the previous and the future recommendations should be ensured. Important examples are the modifications in terminology, the meaning of the dose constraints and the suppression of the dual system of practices/interventions.
- As regards the work schedule, the new recommendations would be really understood only after the foundation documents have been made available and discussed.