Radiation in soil near troubled Japan nuclear plant exceeds Chernobyl evacuation level

The levels of radiation accumulated in soil near the crippled nuclear power plant in northeastern Japan far exceeded the level of radiation the then-Soviet Union had used as a criterion for urging people to evacuate at the time of the 1986 Chernobyl nuclear disaster, threatening to plague local residents for a lengthy period.

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Cesium-137 that has longer effects, ranging from 3 million to 14.7 million becquerels per square meter, was detected in Namie, Futaba, Minamisoma, Iitate and Katsurao, northwest of the Fukushima No. 1 Nuclear Power Plant, in Fukushima Prefecture. The levels far exceeded 550,000 bacquerels per square meter, the level the then-Soviet Union had used as a criterion for urging people to evacuate at the time of the 1986 Chernobyl nuclear disaster.

Based on recommendations from the International Commission on Radiological Protection (ICRP), the Japanese government used 20 millisieverts per year of radiation in the atmosphere as the criterion to designate evacuation areas in the wake of the nuclear accident in Fukushima. Therefore, there are areas that have not been designated as evacuation zones although they have larger amounts of accumulated radiation.

The Ministry of Education, Culture, Sports, Science and Technology says, "Radioactive substances in soil do not enter human bodies immediately." On the other hand, when authorities try to decide whether to allow local residents to return to their homes or resume farming, levels of soil contamination could be one of the hot topics of debate.

http://mdn.mainichi.jp/mdnnews/news/20110511p2a00m0na018000c.html