eSci: Unsafe Radiation Found Near Tokyo, Vast Area of Japan Contaminated, Japan Nuclear Incident Liveblogs, June 16, 2011:
Science Magazine reports that Japanese scientists have become so concerned about the health of their children that they have initiated their own radiation monitoring program and made their own maps. The results are shocking.
Parents in Tokyo’s Koto Ward enlisted the help of Tomoya Yamauchi, a radiation physicist at Kobe University, to measure radiation in their neighborhood. Local government officials later joined the act, ordering radiation checks of schoolyards and other public places and posting the results on their Web sites. An anonymous volunteer recently plotted the available 6300 data points on a map. And Yukio Hayakawa, a volcanologist at Gunma University, turned that plot into a radiation contour map.
It shows one wide belt of radiation reaching 225 kilometers south from the stricken reactors to Tokyo and another extending to the southwest. Within those belts are localized hot spots, including an oval that encloses northeast Tokyo and Kashiwa and neighboring cities in Chiba Prefecture.
Radiation in this zone is 0.4 microsieverts per hour, or about 3.5 millisieverts per year. That is a fraction of the radiation found throughout much of Fukushima Prefecture, which surrounds the nuclear power plant. But it is still 10 times background levels and even above the 1-millisievert-per-year limit for ordinary citizens set by Japanese law. The health effects of such low doses are not clear and are passionately debated. But it is known that children are more susceptible to radiation than adults, and few parents want to take chances with a child’s health. Besides, “The law should be observed,” Yamauchi says. Kyo Kageura, an information scientist at the University of Tokyo, says there should be a public discussion of the issue, “based on a scrupulous presentation of the data, including to what extent the 1-millisievert limit can be achieved.”
Elevated radiation levels widespread in eastern Japan, Smart Planet by David Worthington, June 17, 2011:
A “citizens’ map” of radiation levels is being maintained by a group of Japanese bloggers. Levels appear highest near Fukushima and toward its northwest. The vicinity around immediate southwest of the reactors shows elevated radiation, and a large pocket of contamination has settled further south in the outskirts of Tokyo.
Published: June 18th, 2011 at 10:49 am ET