Fukushima Fallout

Weekly updates by
Keito Hirabayashi

Of the many scientists and experts who have become prominent since the Fukushima nuclear disaster, Kimura Shinzo is one of the heroes in terms of his actions as well as his words. He worked at the National Institute of Radiological Sciences where he was involved with investigations after the Tokaimura accident and has since undertaken extensive research in Chernobyl from his position at a research institute connected with the Ministry of Health, Welfare and Labor. He resigned from this position immediately after the Fukushima accident because he was told not allowed to conduct any research without orders. He felt that all his experience of Tokaimura and Chernobyl would go to waste if he didn’t quit his job, and with a team of supportive scientists, he has been involved in making detailed maps of the radiation contamination caused by Fukushima. In the absence of any information from the government immediately after the accident, it was Dr. Kimura who, through his own measurements of radiation, warned evacuees that they were in highly contaminated areas and has continued monitoring the fallout and the health of people affected. NHK made a documentary on his project which was first screened on May 15th last year—a must-watch.

Kimura Shinzo

Yesterday he arrived back in Japan from Chernobyl and on his way to Niigata, where he is advising the local government on disposing of radioactive debris from Tohoku, he managed to fit in a lecture in the parliament building in Tokyo organized by the Ene-shif Japan group. Many MPs are members of this group and quite a few attended the lecture. They were abuzz with the news that a law on the right to evacuate from radiation contaminated areas had been passed that day. And none too soon, according to what Dr. Kimura had to say. The topic of his talk was: Can residents be protected in a nuclear disaster? And the short answer was that they certainly haven’t been protected so far.

Dr. Kimura began his talk with discussion of the dangers of radiation. The science and statistics often simply confuse ordinary people, and anyway, which science and statistics do you believe? Dr. Kimura cited the 7th BEIR report published by the US National Academies in 2005 which concludes that 1 in 100 people will develop cancer from a single exposure of 100 milli-sieverts (mSv). This report also concludes that:

[notice]At doses of 100 mSv or less, statistical limitations make it difficult to evaluate cancer risk in humans. A comprehensive review of available biological and bio-physical data led the committee to conclude that the risk would continue in a linear fashion at lower doses without a threshold and that the smallest dose has the potential to cause a small increase in risk to humans. This assumption is termed the “linear-no-threshold” (LNT) model.[/notice]

The LNT model would indicate that exposure to10 mSv may cause cancer in 1 in 1000 people. In the case of Chernobyl, areas of more than 20 mSv were designated forced evacuation zones and even areas of 5 mSv or above were compulsory relocation areas, but in Japan there are no restrictions on areas of 5 mSv or below and people continue to live in areas with this amount of radiation. How each of us evaluate risk is a very personal exercise, but Dr. Kimura mentioned an interesting comparison in the world of medicine where the polio vaccine, even though the benefits were very obvious, was estimated to cause damage to 1 in 25,000 children and this made it an object of much discussion and controversy.

Comparisons sometimes do help us put things in perspective and I was reminded of another one mentioned at a Greenpeace press conference recently—that Japan has a massive defence budget, yet the risk that the country will actually be invaded is very small. Why is the government prepared to spend so much protecting its people from foreign invasion and comparatively very little on protecting its people from radiation exposure, even though the risk of this is now much higher?

Dr. Kimura also made an important point concerning the issue of disposing of radioactive debris, which has recently become very controversial in Japan, with different local governments—for example in Kita Kyushu—agreeing to take radioactive debris from the Tohoku disaster area and incinerate it in their municipal facilities, in the face of massive protests by local residents. Dr. Kimura’s take was that this is another attempt by the Nuclear Village to divide the ever growing anti-nuclear movement, into those who don’t want to be exposed to even one becquerel and those who are prepared to help the people in Tohoku dispose of this waste if the risk is low. The problem is, laws on disposal of radioactive waste are full of holes and there are no universal standards or monitoring by which to judge risks and whether or not adequate equipment is in place or not. A lot of work needs to be done in these areas, as there is no doubt that this waste does need to be disposed of somehow and it is also vitally important that this issue does not divide the anti-nuclear movement. In answer to a question about the safety of incinerating radioactive waste, Dr. Kimura said he would have to climb to the top of the incineration chimneys and take radiation measurements to fully determine this—but he seemed quite prepared to do that. Indeed he has faced great personal risk in his mission to accurately map radiation and to get this information to the people who most need it. We need more scientists like him.