Ionising radiation: perhaps we have little to fear except fear itself

Taking Chernobyl first. The United Nations Scientific Committee on the Effects of Atomic radiation UNSCEAR publish periodic reports. In 2008 they produced UNSCEAR 2008. See volume 2 Annex D, Health effects. (www.unscear.org/unscear/en/chernobyl.htmlgives a summary; for Annex D go to bottom of Summary)

Quotations from Annex D are:

The observed health risks currently attributable to radiation exposure are as follows:

• 134 plant staff and emergency workers received high doses of radiation that resulted in acute radiation syndrome(ARS), many of whom also incurred skin injuries due to beta radiation;
• The high radiation doses proved fatal for 28 of these people;
• While 19 ARS survivors have died up to 2006, their deaths have been for various reasons, and usually not associated with radiation exposure;
• Skin injuries and radiation-induced cataracts are major impacts for the ARS survivors;
• Other than this group of emergency workers, several hundred thousand people were involved in recovery operations, but to date, apart from indications of an increase in the incidence of leukaemia and cataracts among those who received higher doses, there is no evidence of health effects that can be attributed to radiation exposure;
• The contamination of milk with I131, for which prompt countermeasures were lacking, resulted in large doses to the thyroids of members of the general public; this led to a substantial fraction of the more than 6000 thyroid cancers observed to date among people who were children or adolescents at the time of the accident (by 2005, 15 cases had proved fatal);
• To date, there has been no persuasive evidence of any other health effect in the general population that can be attributed to radiation exposure.

A general comment under the heading scientific limitations:

… there is reasonable evidence that acute radiation exposure of a large population with doses above 0.1 Sv increases cancer incidence and mortality. So far, neither the most informative study of the survivors of the atomic bombings nor any other studies of adults have provided conclusive evidence for increased incidence of carcinogenic effects at much smaller doses.

There is then an 'UNSCEAR statement';

The Committee has decided not to use models to project absolute numbers of effects in populations exposed to low radiation doses from the Chernobyl accident, because of unacceptable uncertainty in the predictions. It should be stressed that the approach outlined in no way contradicts the application of the LNT model for the purposes of radiation protection, where a cautious approach is conventionally and consciously applied.

In the context of what had gone before, the last sentence is rather peculiar. We will go along with LNT because it is a 'convention'? Since when did science have anything to do with conventionality?

Another remark in the document draws attention to the question as to whether cancers '…are due to the accident or background radiation'.

Variability in background (natural) radiation levels is another fact that may be seen as pointing to a serious questioning of the LNT model. A paper 'Very high background radiation areas of Ramsar, Iran: Preliminary Biological studies' is relevant.

Amongst other things the article gives interesting and relevant data showing wide variability in background radiation levels. Bearing in mind that 20mSv per year is the permitted level for radiation workers it is extraordinary that there is a small area of Ramsar where readings are 260mSv per year. The associated hot springs are used as health spas.