At the Committee on Welfare and Labor in the Japan's House of Representatives 9:00am, July 27, 2011
Next, Witness Kodama, please.
I am Kodama, head of the Radioisotope Center at the University of Tokyo.
I was astounded on March 15.
We, at the Tokyo University, have 27 Radioisotope Centers and are responsible for radiation protection and decontamination.
I am a physician myself and have been involved in decontamination work at facilities in Tokyo University Hospital for a few decades.
We detected 5 microsieverts/hour radiation in Tokai-mura in Ibaraki Prefecture about 9AM on March 15, and notified the Ministry of Education and Science as the "Article 10 notification" [as specified in the Nuclear Disaster Countermeasures Law].
Later, the radiation exceeding 0.5 microsievert/hour was detected in Tokyo.
This level soon went down. And then on March 21 it rained in Tokyo, and with the rain came 0.2 microsievert/hour radiation, and this I believe is the reason for the elevated radiation level to this day.
Chief Cabinet Secretary Edano said at that time, "There is no immediate effect on health". I actually thought this was going to be a big, big problem.
Why was I concerned? Because the current Radiation Damage Prevention Law is based on dealing with a small amount of radioactive materials that emit very high radiation.
In this case, the total amount of radioactive materials is not much of an issue. What matters is how high the radiation is.
However, in the case of the Fukushima I Nuclear Power Plant accident, 5 microsieverts within 100-kilometer radius [he is referring to Tokai-mura], 0.5 microsievert within 200-kilometer radius [referring to Tokyo area],
and the radiation extended far beyond, even to teas in Ashigara and Shizuoka, as everybody now knows.
When we research the radiation injury/sickness, we look at the total amount of radioactive materials.
But there is no definite report from TEPCO or the Japanese government as to exactly how much radioactive materials have been released from Fukushima.
So, using our knowledge base at the Radioisotope Center, we calculated.
Based on the thermal output, it is 29.6 times the amount released by the nuclear bomb dropped on Hiroshima.
In uranium equivalent, it is 20 Hiroshima bombs.
What is more frightening is that whereas the radiation from a nuclear bomb will decrease to one-thousandth in one year, the radiation from a nuclear power plant will only decrease to one-tenth.
In other words, we should recognize from the start that just like Chernobyl, Fukushima I Nuke Plant has released radioactive materials equivalent in the amount to tens of nuclear bombs,
and the resulting contamination is far worse than the contamination by a nuclear bomb.
From a systems biological viewpoint, if the total amount is small, you only have to consider respective amount on each person.
However, when a vast amount of radioactive materials is released, they are in particles.
Dispersion of particles is non-linear, and it's one of the most difficult calculations in the fluid dynamics.
The nuclear fuel is like sands buried in synthetic resin, but once the fuel melts down, a large amount of super-fine particles is released.
What happens then? The problem like the contaminated rice hay happens.
For example, in Fujiwara-cho in Iwate prefecture rice hay with 57,000Bq/kg was found. Osaki in Miyagi Prefecture 17,000Bq/kg,
In Minami-Soma City in Fukushima Prefecture 106,000Bq/kg, and in Shirakawa City in Fukushima 97,000Bq/kg, and Iwate 64,000Bq/kg.
The pattern of contamination does not follow concentric circles.
It depends on the weather. It also depends on where the particles landed - on the material that absorbs water, for example.
We at the Radioisotope Center have been helping Minami Soma City in the decontamination effort. We've done seven decontaminations so far.
When we went to Minami Soma for the first time, there was only one geiger counter.
On March 19 when the Ministry of Agriculture, Forestry and Fisheries supposedly issued the notice [on the cattle feed], food, water, and gasoline were about to be depleted in the city.
The mayor of Minami Soma made a plea for help on the Internet, which was widely viewed.
In that kind of situation, no one would look at a piece of paper from the Ministry, no one would know. Farmers didn't know that rice hay was in danger.
Still, they bought the feed from abroad, paying hundreds of thousands of yen, and started to feed the cows with the same groundwater that they drank.
So, what should we do now? We have to guarantee that the thorough radiation measurement is done in the contaminated area.
As I said before, there was only one geiger counter in Minami Soma City when we went there in May.
In fact, there were 20 personal survey meters provided by the US military. But no one at the city's Board of Education could understand the English manual until we went there and told them how to use them.
That's how it is there.
As to the food inspection, there are more advanced survey meters than germanium counters, such as semiconductor imaging detectors.
Why doesn't the Japanese government spend money in utilizing them?
After 3 months, the government has done no such thing, and I am shaking with anger.
Second, I have been in charge of antibody drugs at the Cabinet Office since Mr. Obuchi was the prime minister [1998-].
We put radioisotopes to antibody drugs to treat cancer. In other words, my job is to inject radioisotopes into human bodies,
so my utmost concern is the internal radiation exposure and that is what I have been studying intensely.
So, I'd like to explain the mechanism of how internal radiation exposure occurs.
The biggest problem of internal radiation is cancer. How does cancer happen? Because radiation cuts DNA strands.
As you know, DNA is in a double helix. When it is in a double helix it is extremely stable.
However, when a cell divides, the double helix becomes single strands, doubles and becomes 4 strands. This stage is the most vulnerable.
Therefore, the fetuses and small children, with cells that rapidly divide, are most susceptible to radiation danger.
Even for adults, there are cells that rapidly divide such as hair, blood cells and intestinal epitheria, and they can be damaged by radiation.
Let me give you an example of what we know about internal radiation exposure.
One genetic mutation does not cause cancer.
After the initial hit by radiation, it needs a different trigger for a cell to mutate into a cancer cell, which is called "driver mutation" or "passenger mutation".
For details please refer to the attached document about the cases in Chernobyl and cesium.
Alpha radiation is most famous. I was startled when I learned of a professor at Tokyo University who said it was safe to drink plutonium.
Alpha radiation is the most dangerous radiation. It causes thorotrast liver damage, as we, liver specialists, know very well.
Internal radiation is frequently referred to as such-and-such millisieverts, but it is utterly meaningless.
Iodine-131 goes to thyroid gland, and thorotrast goes to liver, and cesium goes to urothelium and urinary bladder.
Whole body scan is utterly meaningless unless you look at these parts in the body where radiation accumulates.
Thorotrast was a contrast medium used in Germany since 1890. It was used in Japan since 1930,