ACRO, July 2011
All the children of Fukushima City that had their urine samples tested at ACRO’s laboratory were contaminated with radioactive fallout from the nuclear accident located approximately 60 km away.
ACRO analysed the urine of 10 children to answer to the questions of the parents about internal contamination and the results are without any ambiguity: all samples are tainted by cesium 134 and cesium 137 at concentrations ranging from 0.4 to 1.3 becquerel per liter.
This means that all these children have internal contamination by cesium 134 and 137 and were most probably also contaminated by other short-lived radionuclides like iodine 131. As they all live in a town 60 km from the NPP and eat food from the local supermarkets, other children living closer to the NPP or eating vegetables from the garden might be more contaminated.
At this stage, it is difficult to evaluate the internal contamination and the health consequences from these data. We should learn how and when these children were contaminated. By the food? By breathing?
But these results should encourage the Japanese authorities to systematically measure the internal contamination of people who have been exposed to the radioactive plume and those living in contaminated territories and are therefore probably subjected to chronic contamination. This can be accomplished without technical difficulty. However, only external exposure is taken into account now.
Let me explain. All matter around us, water, air, earth … and we are made up of atoms. Some of these atoms are called « radioactive ». They can emit radiation which can be seen as the firing of a small shell, even smaller than the atom itself. These small shells are dangerous because they can penetrate the human body as when you go to an X-ray.
A radioactive atom has no target. If it is next to us, it is likely that the shells go far away. But if you eat contaminated vegetables, drink polluted water and breathe air polluted by radioactive atoms, the shells fired by the atoms in the body will do damage every time! Thus, contaminated food may not be dangerous if it is on the plate before us and become dangerous if swallowed.
To define evacuation zones, the Japanese authorities only take into account the soil contamination that cause external radiation, ie the shells fired on the outside of the body. But we must add the internal contamination which is currently completely omitted from the calculations of radiation exposure. As soil and vegetables grown on site are also contaminated, this internal contamination might continue.
This also reinforces the idea that the limit set by the Japanese authorities to determine evacuation areas is too high. It is fixed at 20 millisieverts per year, which is strongly criticized by many organizations including ACRO. The sievert is the unit used to measure the damage caused by radiation on the body. This limit is two times more than the French one in case of nuclear accidents and twenty times higher than the maximum allowable limit for the public under normal circumstances.
The limit of 20 millisieverts is the one that applies to the most exposed nuclear workers. Their exposure doses would be monitored and be entitled to medical care. As nuclear workers, children of Fukushima would have a limit of 20 millisieverts. As nuclear workers, school children would be equipped with dosimeters to measure external radiation dose they receive. But unlike these workers, the children did not choose to be in that environment.
For a worker’s nuclear internal contamination must be exceptional. For some of the children in Fukushima, this may be routine…
It is therefore imperative that families have access to the measurement of radioactivity. This is why ACRO has launched a subscription to open an independent laboratory for analysis of radioactivity in Japan.