On February 28, 2013, the World Health Organization (WHO) published its health risk assessment from the nuclear accident after the 2011 Great East Japan earthquake and tsunami. This report concluded that for the general population inside and outside of Japan, the predicted risks are low and no observable increases in cancer rates above baseline rates are expected. The assessment is based on preliminary dose estimations, published by the WHO in May 2012 , which were strictly criticized by the German Section of IPPNW, independent researchers, and Japanese civil organizations. This analysis will discuss main objections to the current WHO report and shows why it should not be considered a neutral scientific assessment of the actual health risks of the affected population, nor a reasonable basis for future decisions and recommendations.
The main point of criticism to this report has to be the fact that the health risk assessment is based on dose assessments, which are ambiguous, if not to say plain wrong. The source term estimates (the total emission of radioactive particles) used in the WHO report were significantly lower than those of independent research institutions and in some cases also lower than Tokyo Electric Power Company (TEPCO)’s own measurements. The exposure of the population living in the 20km zone around the nuclear plant was omitted, even though this population may have been exposed to high levels of iodine-131 before and during the chaotic evacuations. The quantity and selection of food samples used in the calculations of the internal radiation dose were shown to be inadequate and in contrast to samples published by the Japanese authorities. Finally and crucially, the report was mainly composed by scientists working for organizations with stakes in the continued and profitable utilization of nuclear energy, casting doubts on the neutrality of the report’s findings. All of these detailed points of criticism can be found in the report by IPPNW Germany entitled ‘Analysis of WHO report on Fukushima catastrophe’. No matter how expertly undertaken, a calculation of health risks can only be as exact as the assumptions that it is based on. An assessment that relies on data, whose reasonableness has to be questioned on the grounds of lacking neutrality, selective sampling, distortion and omission of relevant facts, cannot be accepted by the scientific community as a basis on which to make health recommendations.
Also, the report ignores the health risks for people outside of Fukushima. While radiation was spread to a large area of northeastern Japan, including the capital Tokyo, and polluted food, soil and waste were distributed beyond the borders of Fukushima prefecture, only the fourteen most affected residential areas (Group 1 and 2 of the WHO report) were considered for the total health risk assessment. As a result of that, negating any measurable health effects for the population of the rest of Fukushima prefecture, Japan and the world. In fact, the report makes the claim that outside the geographical areas most affected by radiation, even in locations within Fukushima prefecture, the predicted risks remain low and no observable increases in cancer above natural variation in baseline rates are expected. From the Chernobyl disaster, however, that while the most affected populations were the ones living in the highly polluted fallout zones, a great number of people living in the less contaminated areas in the former Soviet Union, Europe and Asia Minor, were also affected, leading to increased incidences of morbidity and mortality. As the health effects of low-dose radiation are not be predicted precisely in nature and as the generally accepted tool for calculating cancer risk is the linear non- threshold (LNT) model, the exposure of a small population with a high amount of radioactivity can have the similar results in absolute numbers of cancer cases, as the exposure of a large population with a relatively small amount of radioactivity. While the effects by small amounts of low-dose radiation on large populations are generally more difficult to identify in epidemiologic studies, discounting them altogether disregards a large amount of cases in absolute numbers and can only be seen as an attempt to downplay the expected health effects of the nuclear disaster.
Moreover, continued radioactive emissions were not included in the assessment. The WHO report treats the nuclear catastrophe of Fukushima as a singular event and does not take into consideration continued emissions of radioactivity after the initial nuclear meltdowns in March 2011. In the WHO dose assessment report of May 2012, the authors wrote, ‘the contribution from iodine to the total exposure was considered to be zero from four months after the start of the release.’ This assumes that radioactive iodine was released only at the very beginning of the nuclear catastrophe and that no further emissions occurred, allowing iodine-131 levels to fall due to radioactive decay. However, in June of 2011, Japanese government scientists still found iodine-131 concentrations of more than 200 Bq/kg in numerous municipalities of Fukushima prefecture, with maximum ranges found in Namie and Iitate of 1,300 and 1,100 Bq/kg, respectively. As iodine-131 has a half-life of 8 days, measurements this high, 90 days after the initial fallout on March 15 , 2011, suggest additional contamination of the area with iodine-131 at a later time.
The report also ignores the increased radiosensitivity of the unborn child. The authors of the report claim that the estimated dose levels of the population affected by the Fukushima disaster were too low to affect fetal development, and therefore excluded the possibility of miscarriages, increased perinatal mortality, congenital defects or cognitive impairments due to in 17 utero exposure. The report also states that the radiosensitivity of a fetus was considered by the authors to be the same as for a one-year old child. In fact, the unborn child is the most sensitive form of human life: higher tissue-metabolism and cell-division rates in a fetus increase the chance that mutations cause malignancies before they can be stopped by the body’s self-regulatory mechanisms.
Furthermore, non-cancer diseases are not included in the health risk calculations. Non-cancer health effects, such as cardiovascular diseases (CVD), infertility or thyroid disease were not assessed quantitatively in the report. Furthermore, the possibility of such effects occurring as a result of the Fukushima nuclear catastrophe was disregarded altogether. The authors assumed that only high levels of radioactivity could lead to such effects, discounting the research on the effects of low-dose radiation.
At last, the authors’ neutrality has to be doubted. One of the main points of criticism of the WHO dose assessment of May 2012 was its apparent lack of neutrality. With an expert panel comprised mainly of scientists associated with the International Atomic Energy Agency (IAEA) and members of nuclear regulatory bodies accused of collusion with the nuclear industry, and with findings that differ so significantly from other, independent research publications, the dose assessment gave the impression of attempting to downplay the effects of the nuclear disaster, rather than constituting a meaningful scientific approach to the issue of radiation exposure in Fukushima. It remains unclear why a report, written mainly by the IAEA and collaborating nuclear institutions, would need to be published in the name of the WHO.
In conclusion, scientists are fully aware of the difficulties in calculating comprehensive health risks of a large disaster for such a large population and know of the problems that naturally arise in such an attempt. It is extremely important to base calculations such as these on reliable and valid data, which has been approved by a scientific general agreement either through an impartial expert panel composed of scientists with opposite views, or through a critical peer review process. The possibility of a manipulation of data by a group, organization or industry with vested interests should be avoided at all costs. The calculations should surround the entire population affected by the disaster and should give special consideration to groups with heightened weakness. Clinical findings should be thoroughly assessed and included in the final considerations.