Recommendation: Fukushima University and Fukushima Prefecture should seriously take into account the possible risk of low-level radiation exposure
(April 27, 2011)
The explosion at TEPCO's Fukushima Daiichi Nuclear Plant has released a huge amount of radioactive material into the environment. We would like to talk about the risks associated with this accident from the point of view of people who are actually exposed to radiation.
[Existing views on the risk of low-level radiation exposure]
The level of radiation exposure that we are referring to here is a level of less than 100 millisieverts. For example, in Fukushima City, residents were exposed to a total of about 3.5 millisieverts in the month following the accident. Currently, on April 27, they are being exposed to 1.5 microsieverts per hour, so some people in the city will probably end up with a total exposure of 10 millisieverts after a year. Of course, these figures relate only to external exposure. In addition, it is also necessary to consider internal exposure.
At present, expert opinion both in Japan and abroad is divided on the question of the impact of low-level radiation on human health. Broadly speaking, three main positions on this issue can be identified, as listed below. The institutions that support each of these positions are shown in square brackets.
(1) Radiation below a certain level has absolutely no ill-effects
[French Academy of Sciences — National Academy of Medicine]
(2) The lower the amount of radiation, the lower the risk. However, any amount of radiation poses some risk (in other words, no matter how low the amount, the risk is never zero).
[U.S. National Academy of Sciences, United Nations Scientific Committee on the Effects of Atomic Radiation, International Commission on Radiological Protection (ICRP)]
(3) The fact that the level of radiation is low does not necessarily mean that the risk decreases
[European Committee on Radiation Risk (ECRR)]
In addition, there are those who argue that low levels of radiation are actually beneficial to human health. For the purposes of the discussion here, this position is treated as part of position (1).
Of these three positions, wedo not know which is correct. However, it is clear that position (2) is by no means a minority position. Further, given the fact that scientific knowledge about the effects of low-level radiation is at present still insufficient, it would be unscientific to ignore positions (2) and (3) and simply insist upon position (1).
Why do a variety of positions on this issue exist in the first place? One possible reason is that experimental studies to date have not found that exposure to radiation of less than 100 millisieverts necessarily has a harmful impact on health*1.
We do not know if this is true or not, but let us assume that it is the case. Must people like us, who have been exposed to radiation, wait until further experimental studies have been carried out? In effect, provisionally accepting that exposure to low levels of radiation is safe until studies have proved that a causal connection exists between exposure and harm to human health means doing nothing until victims have actually been identified. However, we have the right not to be treated as guinea pigs or as an experimental "sample."
Therefore, the position that should be adopted at present is one based on the assumption that the risk posed by low-level radiation is not zero.
[Our demands to Fukushima Prefecture and Fukushima University]
In order to allay the concerns of residents about radiation exposure, Fukushima Prefecture has invited a number of experts from outside the prefecture to serve as radiation health risk management advisors. These advisors believe that they can ignore the issue of health effects caused by low-level radiation exposure, and in effect are adherents of position (1) described above.
At Fukushima University, too, a message from the president of the university posted on the university's public website asserts that the levels of radiation on the Fukushima University campus are safe. Further, the university is also working hard to create the impression that the campus is safe by taking such measures as inviting the prefecture'sradiation health risk management advisors to speak at meetings organized by the university.
However, with regard to the question of the risk posed by low-level radiation, if we take into account the fact that positions (2) and (3) described above exist, this kind of manipulation of information is not fair. We therefore make the following demands:
* Fukushima Prefecture should also invite experts who advocate positions (2) and (3) to serve asradiation health risk management advisors.
* Fukushima Prefecture and Fukushima University should take concrete measures (such as distributing masks and dosimeters) to prevent exposure to low-level radiation, based on recognition of the fact that from the point of view of positions (2) and (3), it cannot be argued that the risk posed by low levels of radiation is zero.
[Evaluation of uncertainty]
If even low levels of radiation pose some risk, how can we estimate what this risk actually is? According to ICRP recommendations, the risk of dying from cancer increases by 0.05 for every additional sievert of exposure, but no-one can say for sure if this is the case or not. The actual risk may be much lower, or much greater. The ECRR criticizes the ICRP position as underestimating the risks posed by internal radiation exposure.
Further, even if the risk is indeed 0.05 (for example, 5 out of 10,000 people exposed to 10 millisieverts of radiation will die from cancer), the people who should decide whether this risk is acceptable or too great are those actually exposed to the radiation.
It is out of the question for those not exposed to radiation to lightly dismiss the problem by arguing that it is acceptable to ignore the risk of negative effects because the probability that they will occur is low.
Hiding information that may cause people anxiety may have beneficial effects in the short term.
However, it may also cause irreparable damage in the long term.
Plans to protect and nurture people must look 50 years into the future.
We believe that the role of the government should be to protect people over the long term, not to focus on short-term benefits, and that of the university should be to nurture people over the long term.
(Authored by Hazuki Ishida)
*1 A reader commented that to avoid misinterpretation this should be phrased as "no surveys have been carried outin the first placethat could show that exposure to low levels of radiation necessarily has a harmful impact on health."
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