The impact of ionising radiation on health is a subject on which highly polarised views exist. Official reports often appear more concerned with alleviating public worries on radiation risks than with presenting the evidence as clearly as possible without fudges or omissions. On the other hand some hypotheses, for example, suggest that radiation is hundreds of times more dangerous than official sources indicate.
Radiation risks are complex and can be difficult to explain. For example, there are no simple answers to reasonable questions like “is it safe to live near Sellafield?” What we can say is that there is no such thing as an absolutely safe level of radiation: all exposures no matter how small entail some risk – even background radiation. (See Radiation and Health Row, NuClear News No.15, February 2010.)
Recommendations on radiation risks are made by the International Commission on Radiological Protection (ICRP) – an unofficial body whose pronouncements carry much weight. The ICRP’s recommendations are then legislated for by the European Union and applied in the UK with advice from the Health Protection Agency. These risks are estimated mainly from the health effects resulting from the very brief external irradiation from the Hiroshima and Nagasaki atomic bombs. Many believe these risks may not be appropriate when applied to predicting the health consequences of chronic irradiation from radionuclides deposited within the body.
Debate on the ICRP approach to radiation risks was sparked in 1983, following the discovery by Yorkshire TV of an excess of childhood leukaemias and other cancers in the village of Seascale near Sellafield. Following the report of the subsequent enquiry, the Government established the Committee on Medical Aspects of Radiation in the Environment (COMARE). The committee’s first report in 1986 concluded that the estimated radiation doses, calculated from Sellafield’s recorded releases and from measured radionuclide concentrations in the environment, were too small by a factor of about 400 to account for the increased incidence of leukaemia among the children of Seascale. A more straightforward explanation was that the ICRP risk models were incorrect but this was not discussed.
In 2004 the Government appointed Committee Examining Radiation Risks of Internal Emitters (CERRIE) concluded that uncertainties about the risks from radiation inside the body mean we could be exposed to 10 times the risk previously thought in some cases, so we should adopt a precautionary approach.1
A 2008 study carried out in Germany known as the KiKK study2 found a 120% increase in leukaemias and a 60% increase in solid cancers among children under 5 years old living within 5 km of all German nuclear power stations. These increased cancer rates were unequivocally linked to proximity to nuclear reactors. The study’s findings support over 60 other studies worldwide on increased childhood cancer near nuclear power stations. KiKK is an important study because of its large size and statistical power, and because it was commissioned by the German Government. It is now officially accepted in Germany that children living near nuclear power plants develop cancer and leukaemia more frequently than those living further away.
Some authors have concluded that these leukemia risks near German nuclear power stations cast“significant doubt” over the official doses received by people living nearby. In other words, the official methodology used for estimating radiation doses near nuclear stations may be unreliable. Writing in the scientific journal Environmental Health, Dr Ian Fairlie proposed a hypothesis to explain the discrepancy between the large risks and small estimated radiation doses near NPPs. He suggests that spikes in environmental emissions from nuclear reactors result in doses to embryos and foetuses in pregnant women near nuclear power stations may be larger than suspected. Hematopoietic tissues – which form blood cells – appear to be considerably more radiosensitive in embryos and foetuses than in newborn babies.3
Fairlie says estimated radiation doses to adults near nuclear power stations are invariably very low. How these estimates are derived is not widely understood by scientists, and not at all by members of the public. In fact, the methodology is quite complicated, and is derived using at least four computer models in sequence. The problem is that each model gives a result which is inherently uncertain. Since the result from each model has to be combined, the cumulative uncertainty in dose estimates could be very large. Once you have an estimated dose you then have to estimate the risk associated with that dose to estimate the likely level of cancers, and large uncertainties could exist in this model as well.
Dr Fairlie concludes that the KiKK study raises many questions, including whether vulnerable people, such as pregnant women and women of child-bearing age, should be advised to move away from the immediate vicinity of nuclear power stations. He told The Guardian: “In my view, the KiKK report is a showstopper for the government’s plans for more nuclear power stations. It’s impossible to justify killing children near nuclear power plants: there are many safer ways to generate electricity.”4
In November 2009, the Department of Health asked COMARE to carry out a review of the incidence of childhood leukaemia near most UK nuclear power plants (NPPs) as a response to the KiKK study. This was intended to extend timewise a 2008 study to include more recent data in order to increase the statistical strength of its findings.
The resulting COMARE report – 14th Report – was published in May 2011. It was widely reported as providing evidence that nuclear power plants did not cause childhood cancers. The Committee said we should now be looking for other reasons, perhaps infections or even viruses, to explain leukaemia clusters. However these conclusions were scientifically incorrect.
The earlier 2008 study commissioned by the Department of Health had found a 36% increase in acute childhood leukaemias between 1969 and 2004 within 5 km of 13 of the 14 UK nuclear power stations but this increase was not considered statistically significant. COMARE’s 14th Report actually uses the same 1969 to 2004 time period as the 2008 study despite being requested to extend the time period. It does however add non-Hodgkins lymphomas (NHL), chronic myeloprolific diseases, and unspecified leukaemias to the acute leukaemias examined in 2008. These are strange inclusions as there are no actual cases of these extra diseases in the 5 km circles near British NPPs in the study period, and these disease categories were not used in the KiKK study which was supposed to be replicated.
COMARE still found a 22% increase in childhood acute leukaemia, non-Hodgkins lymphoma (NHL), chronic myeloprolific disease and unspecified leukaemia. This was called a negative finding because it lacked statistical significance. This also was scientifically incorrect. What COMARE should have stated was that a leukaemia increase was found which was not statistically significant, but that this could simply be due to small numbers.
In 2012 a French study of childhood leukaemia near nuclear power plants found a statistically significant increase in leukaemia in children below age 15 in 2002-2007 within 5 km of 19 French nuclear power stations.5 Including the KiKK and COMARE reports there are now four European reports showing an increase in childhood leukaemias in the vicinity of nuclear power stations – another one in Germany and one in Switzerland. (See Possible mechanism explaining leukaemia clusters, NuClear News No.37 February 2012.)
1.CERRIE Press Release 20th October 2004
2.Weiss W. Background information on the KiKK study. German Federal Office for Radiation Protection 2007, Berlin,Germany. Available in English.
3. Fairlie, I. Commentary: Childhood Cancer Near Nuclear Power Stations. Environmental Health Journal, 2009. 8:43
4. Guardian 7th March 2010
5. Dr Ian Fairlie 20th Jan 2012