Questions about contamination

Tokyo

The Jan. 29 Kyodo article “Fukushima kids’ thyroids said safe” indicates that radiation levels in the thyroids of 1-year-old kids living near the Fukushima No. 1 nuclear power plant are “estimated to be less than 30 millisieverts in most cases,” based on medical exams of 1,000 children. The story goes on to indicate that these levels are “lower than the 50-millisievert threshold set by the International Atomic Energy Agency.”

Although that’s some consolation for the affected people, more to the point would be a comparison with what constitutes “normal levels.” For example, how many millisieverts (if any) of radioactivity show up in children not affected by the disaster — say, kids living in Kyushu? As we’re talking about radioactive contamination of the thyroid gland, does it mean that these children will continue to be exposed to radioactivity to the tune of 30 millisieverts every year?

Finally, what’s causing the radioactivity? Since iodine has a half-life of eight days, is it cesium 136/138 with an approximate half-life of 30 years? I’d appreciate it if your news stories delved a bit more into these questions rather than just report an announcement.

william ireton
tokyo

The opinions expressed in this letter to the editor are the writer’s own and do not necessarily reflect the policies of The Japan Times.