Predicting the global health consequences of the Chernobyl accident
according to the methodology of the European Committee on Radiation Risk
This page summarises the report. The report itself is here

The last 25 years have witnessed a wide range of predicted health outcomes from post-Chernobyl accident exposures. The Committee has revisited some of these calculations and has applied its own approach to predicting the cancer yield and other health effects.

Uncertainty about how much of the Chernobyl reactor's contents were released (the source term) is one cause of disagreement about its effects.
The Committee bases its own assessment on two kinds of input

• The first is the effective first year dose to individuals in the populations of 39 nations - a total of 2,342 million people.
• The second input is the mean area contamination by Caesium-137. This has been converted into dose using a standard method.

The cancer yield has been calculated in two ways:

• the absolute ECRR 2010 method. This requires doses to be modified in light of UNSCEAR data for the ratios of internal and external radiation. The output is in terms of incident cancers in 50 years following exposure.
• the Tondel method, based on studies of cancer in Sweden which found an 11% increase in cancer for each 100kBq/m2 Cs-137 contamination. The output is in terms of incident cancers in the 10 years following exposure.

(These calculations do not assume that the cancer is caused by the Cs-137 exposure; Cs-137 is seen as a flag indicating the presence of a range of harmful radionuclides.)

Results
The two methods show approximately 492,000 in the 10 years following exposure and 1.4 million incident cancers in 50 years. There is good agreement between the results. The yield of about 1.4 million cancers worldwide also agrees quite well with independent calculations by John Gofman, Rosalie Bertell and Alexey Yablokov.
It should be noted that the ECRR method was developed in 2003, before Tondel et al published the results of their study of cancer in Sweden. ECRR 2003 method predicted what they found with a fair degree of accuracy. It should also be noted that the Caesium contamination levels associated with the Tondel findings give annual external doses of about 3mSv, around natural background, and should not have caused any observable increase in cancer, according to the ICRP model.

This study has focused only on cancer. ECRR2010 also predicts significant harm from a wide range of conditions and causes of death, including heart disease, strokes, diabetes, congenital illness in children, infant mortality and loss of fertility as a result of damage to sperm and ova. In general it is now clear that radiation causes a general loss of lifespan through premature ageing and therefore, as in the areas heavily contaminated from Chernobyl, the overall increases in cancer predicted here on a linear basis may be truncated at higher doses by competing causes of early death.

The agreement between the ECRR2003 method employed and real data on cancer from ex Soviet Union areas contaminated by Chernobyl, from weapons fallout and Sweden after Chernobyl suggests that the current approach to modelling radiation risk based on the ICRP dependence on the external exposures of the Japan A-Bomb survivor cohorts is erroneous. The Committee has previously cricised the ICRP model. These matters have significant implications for policy in the case of Fukushima.

The Committee believes that this is an important issue and accordingly publishes its report as a freely downloadable PDF. (180Kb)