2005 ICRP Recommendation

Draft document: 2005 ICRP Recommendation
Submitted by Charles B Meinhold, Member Emeritus ICRP
Commenting as an individual

This set of comments is in addition to those I provided last summer. While those comments still apply I did want to provide a somewhat more in-depth analysis. These new comments are given below by paragraph number. A summary of my major concerns is the use of the 1990 dose limit values as constraints (see comments on paragraphs (S7) and (S8)), and the emphasis on natural background radiation as the basis for selecting values of constraints.(see comments onsection 6. Comments (S6) Last sentence: Why is “This requirement” the concern of only management and regulators? Workers and other stakeholders may have a role to play. (S7)/(S8) Although I heartily agree on the emphasis on source related dose constraints, I heartily disagree with the dose constraint values as given in Table S1. They seem to be identical to the dose limits for normal exposure situations for both workers and individual members of the public. Many workers have more than one place of employment (source) and must be protected by a dose limit. (particularly since the annual committed risk associated with 20 mSv is similar to that of a deep sea fisherman (~10-3) per year. With regard to the public, the application of a dose limit is virtually impossible and source related constraints are clearly a more desirable approach to protection of the public. However, in (S8) you continue to recommend the 1990 dose limits (1mSv per year or 5mSv over 5 years.) and then recommend the same value for the constraint. It would seem that a more coherent approach would be to justify the constraint value in terms of the expectation of any individual being exposed to more than one source and an endorsement of whatever that total dose might be. (40) In this summary, the concept of effects at low dose (region of stochastic effects) as opposed to those at high dose (deterministic) seems to get lost in the discussion of effects with low LET versus high LET radiations. (47) Do you really have radiobiological experiments which give results between low LET (<10 keV per micro) and ~100 keV per micron? If the commission is attempting to be “transparent” in their recommendations the Q/LET, or what ever you used in making your “judgments”, should be given. It is much better in (61) but the Q/LET relationship should be given either here or there. 4.2 An excellent discussion. (112/113) It might be helpful to point that there is a moderate increase in the estimate of “fatal cancer” but a substantial decease in heritable effects. (136) The word “power” might be a little contentious; perhaps “authority” is better Fig #2 following (139) illustrates exactly my comments on (S7/S8) (150) The first sentence is excellent. The rest of the paragraph represents the hopes and dreams of the Commission but goes far beyond providing “guidance” If the recommendation are judged to be helpful, they will be adopted. It’s not for the Commission to decide this. (152) I would strongly suggest changing the second sentence to “While all these bodies may find the Commission’s publications to be helpful, the Commission’s advice is aimed principally at the regulators and managements that have direct responsibility for radiological protection.” (153) While this paragraph has been improved for the previous draft I might suggest a further soften of this advice to “A major responsibility of regulatory authorities is to encourage.” (154/155) These two paragraphs are confusing, unhelpful and unnecessary. Paragraph (149) says all that needs to be said. Section 6 It is with this section that I have the most difficulties. I had encouraged the Chairman of the Commission to distribute his proposal on using the ranges of natural background as the basis of selecting dose limiting values. I have always felt natural background was a helpful in giving uninformed people something they could understand in discussions on exposure scenarios. There is simply no scientific basis for using natural background. This idea has traditionally been weakest part of the scientifically based judgments of ICRP and NCRP However I have also been concerned that it has been the recent history of the ICRP and NCRP to use the natural background as a basis for their limit for the public. (Even that was strange since it excluded radon exposure –the largest component of the average natural background.). I would have hoped that this next evolution in providing dose-limiting values might have been the development for a scientifically based approach for a public dose limit. Instead, to my dismay, you give the impression in this section that all your judgments are based on the values of natural background. A careful reading of this section however belies that impression. I sincerely hope that the final draft of this report can eliminate paragraph (157) and Fig 3. None of the decisions other than that for natural background appear to have any relation to this figure