Health risks attributable to radiation

Draft document: Health risks attributable to radiation
Submitted by Ron Cameron, ARPS
Commenting on behalf of the organisation

1. ARPS welcomes the opportunity to comment on the draft document. 2. ARPS recognizes the expertise and knowledge reflected in the draft Foundation Document, and the quality of writing, and commends the Commission on producing a valuable reference document. 3. However, ARPS wishes to invite the Commission to consider the following comments and suggestions in the interests of completeness and of anticipating future criticism. (a) It could be useful to include in the Foundation Document some additional discussion of reports in the literature concerning radiation hormesis. Adaptive response to acute (but not to chronic) exposure is briefly discussed in several places but it is concluded that knowledge is "insufficiently well developed for radiological protection purposes". This is similar to what was said about hormesis in 1990. There have been many reports on radiation hormesis published since 1990 that merit comment but that are not discussed in the Foundation Document. For example, a paper by Mitchel and Boreham (IRPA10 Proceedings), reports a 3 to 4-fold reduction of spontaneous malignant transformations in rodent cells in vitro when exposed to doses ranging from 1mGy to 100mGy. If a similar result were to be observed in vivo in humans for protracted doses, it could have a profound effect on radiation protection policy. The LNT and hormesis models are mutually exclusive and the LNT assumption is not conservative or precautionary if hormesis occurs. In order to assist in resolving as far as possible the differences of opinion concerning the adoption of the LNT hypothesis, it would therefore be helpful for the Foundation Document either to provide an analytical review of pertinent studies or to make a statement as to why they do not deserve attention in this report. Otherwise, an impression can be created that the report is selective in the work it assesses. The discussion of Section 4.4.5 is noted, but it would improved by including a clear statement as to why the hormesis literature has been discounted. (b) For similar reasons, it might be considered that the Foundation Document should comment upon any evidence that is available concerning the health of populations living in areas of high background dose. There appears to be a lack of evidence of harm (which of course is not evidence of lack of harm) in populations receiving from five to more than fifty mSv per year.