Radiation Health Risk Management
There was held an urgent press conference at the Foreing Correspondents' Club of Japan in Yurakucho, Tokyo on March 22, from 3pm to 4pm for about an hour.
Professor Shunichi Yamashita addressed the issue of radiation exposerure from the Fukushima Daiichi nulear power plant accident to correct misconceptions of the people of Japan and abroad. Professor Yamashita is an authority on the subject with lenghty experience caring for patients suffering fro radiation exposure form the atomic bombs and Chernobyl nuclear power plant disaster.
Fukushima Prefecture on March 19 newly appointed Professor Yamashita as an Adviser on health-risk management from nuclear radiation.
Professor Yamashita is the dean of the Graduate School o0f Biomedical Sciences at Nagasaki University and professor and chairman of the Department of
Molecular Medicine and Department of International Health and Radiation Research at the Atomic Bomb Disease Institute of Nagasaki University School of Medicine. He also works as a director of the WHO Collaboration Center for Research on Radiation Emergency Medicine.
Professor Yamashita explained using slides and distributed two sheets of paper in English and a sheet of paper written in Japanese language.
Here the English language paper circulated at the press conference and full text are reproduced here as follows.
[Professor Toshikazu Yamashita, Nagasaki Univershity
長崎大学大学院医歯薬学総合研究科 原爆後障害医療研究施設 教授
Prof Yamashita is currently the Radiation Health Risk Mangement advisor at Fukushima overlooiing teh area's medical facilities for radiation exposure.
About the initial evacuation
During the first week, it was unfortunate that the quick succession of unpredicted events had made it difficult for everyone to share information. Ifirst became aware of the seriousness of the situation when the government issued an evacuation warning that didn't follow the usual standards. Normally peoploe living within 10km of the site would be to [be]evacuated in the case of emergency . People would first be asked to stay indoors , and then be given the order to eveacuate if the radiation loevels wouldn't drop. In the current case, people living within 20km were evacuated , and then people living within 30km were told to stay indoors. It doesn't make sense that people who had been evacuated to a sagfer area should be asked to stay indoors.
The seires of troubles at the reactor were unprecedented. Radiation continues to come out at an on-again, off-again basis. The type of radiation coming out varies, so do the amounts. We need to continue monitoring the area and find out whether the 30km indoor evacuation is necessary.
The effects of radioactive antereial as compareto the Chernobyl disaster
Radioactive material has spread across a number of places. In a way though, radioactive materials emit what's called a tracer, which is very easily detected and measured. The amounts tha thve been recorded so far will not have an effect people's health. If the extent of the Chernobyl nuclear disaster could be represented by Mount Pinatubo's eruption in the Philippines, the incident at Fukushima would be represented by the Mount Unzen or Shinmoedake volcanic eruption. In either case, there's a risk of getting burns or something more life threatening form the volcanic ash or lava, but moving away form the area lowers these chances. The only difference betwen the two is that Mt Pinatubo's effect spread across the entire world, whereas Mt Unzen or Shinmoedake only affected a small area.
Radioactive material cojming out of Fukushima Daiichi is like ash spewing out of an erupting volcano. MOving away 20km will significantly lowere its effects. The amount of radioactive material that has been released up to now is getting smaller and smaller as is the area over which it is being spread. A person who gets radioactive material on their skin can easily wash it off. It's wrong to say that even a trace of exposeure would be dangerous.
Currently, the chances of getting cancer are not rising
Human bodies already contain about 1000 to 5000Bq of radioactive potassium. Taking a radon basth will obviously result in your bosy abosorging radon too. As long as the amount of these radioactive matereilas are small(10--500μSv) then in there shouldn't be a problem over a relatively short perioud of time.
Right now iodine-131 levels in spinach and milk have gone over the standard limits, but it's safe to eat once or twice. The other thing ins iodine-131 has a half-life opf eight days so its effects will ear off quickly.
Being exposed to 100mSv of radiation at once could raise the chances of getting cancer, but if the levels can be kept below 50mSv it should be alright. Radiation exposures considered safe for the nuclear powere plant workers has been set to a total of 50mSv per year, and this is secure.
People seem to be worried that radiation exposure will lead to cancer later on in life. but if we exposed 100 people to a 100mSv dose of radiation , onloy one or two people would have a chance of getting cancer(one in three Japanese people die from cancer). Thus, it's ulikely more people will get cancer as a result of these events.
No need to worry about radiation exosure for general public
In the area between 10km-20km from the nuclear plant, who are already evacuated, might have benn exposed to about 1mSv of radiation. However, there is no diffierence between sevral icor-SV and 100 mSV in terms of ehir effect in causinhg cancer.
It should also be noted that the effect of radiation of exposeure, 100times fo 1mSv abd 100mSv at a time, is very different. The people weshoulbe worry about with regard to radiation exposure are those working at the site of Fukushima Daiichi nuclear power plant. We neet to think how to secure their health. Otherwise people do not need to worry about radiation exposure.
It is argued that the effect of low-level radiation exposure on health conditions cannnot be demonstarated. However, "no evidence of no effect" does not necessarily mean we should worry about the effedft. It is undersatandable that people fear the radiation exposeure because it is invisible , but radiatin dcanbe measured in scientific ways. That is, we have ameans to prevent harm from radiation. We should not get in panic. I would ask you to behave in a rational manner as a member of the society.
Radiation has spread across a wide area so it would be a proble if food is contaminated through the food chain and then sold at markets. We need to collect data aout hat areas have been contaminated in what ways, and be open withy shaing this data. Using this information will help us to calculate radiation levels absorbed into our body within a year , andif the total annual intake is anyshere between a few tens of mSv to 100mSv, then regulations need to be put into place. I do think this wilol toughten Japan's already strict food safety standards, but we need to pay particular attentino to the prevention orf negative rumous from spreading.
Given the scale of the impact of this earthquake and its consequent tragedies, I argue that peopole in this nation should be prepared to help relieve the burden the people of Fukushima now face. It is nbw that we need to follow the examle of the Japanese way and carry on in harmonoious and calm way as our ancestors have through history.]