After the massive nuclear disaster due to earthquake and tsunami last year, the Japan government on July 25, 2012 said that radioactive strontium has been detected in ten prefectures across Japan. It was confirmed by the Ministry of Education, Culture, Sports, Science and Technology that small amounts of radioactive strontium has been detected in Iwate, Akita, Yamagata, Ibaraki, Tochigi, Gunma, Saitama, Chiba and Kanagawa prefectures along with Tokyo.

It was also revealed by the ministry that highest level of radioactive strontium has been detected in Ibaraki here the readings of 6 becquerels per square meter were detected. A spokesperson from the company said that the radiation at this level has a negligible effect on human health.

The findings of the government come weeks after the Tokyo Shimbun reported the Koto Association for the Protection of Children held at a press conference in the Tokyo metropolitan government building on June 7, 2012. The press conference was held to announce the results of the survey that it carried out.

The results showed high levels of radioactive cesium in an athletic ground near the Tobu sewage sludge processing plant in Tokyo. The research was carried out by the association and Professors Tomoya Yamauchi of Kobe University.