Meltdowns pushed strontium 90 levels up in Kanto and Tohoku

July 25, 2012

Strontium 90 levels in Kanto, Tohoku rise after Fukushima meltdowns

http://mainichi.jp/english/english/newsselect/news/20120725p2a00m0na004000c.html

Strontium 90 released in the Fukushima nuclear disaster has pushed levels of the radioactive element in the Kanto and Tohoku regions higher than any recorded since between the year 2000 and the meltdowns last year, a government study released July 24 has revealed.

The nationwide airborne survey conducted by the Ministry of Education, Culture, Sports, Science and Technology found the higher levels in 10 Kanto- and Tohoku-area prefectures (excluding Miyagi and Fukushima, where strontium 90 was detected in soil samples). The study results did not confirm whether other regions had been affected by the release of the element in the nuclear disaster.

If taken internally, strontium 90 tends to collect in the bones, though the science ministry has emphasized that the amounts detected are extremely small and present no risk to human health.

The highest strontium 90 level ever detected in the regions was 358 becquerels per square meter in Miyagi Prefecture in 1963, when both the United States and the former Soviet Union conducted regular nuclear weapons tests. The highest level found from 2000 to before the Fukushima nuclear disaster was 0.3 becquerels per square meter in Hokkaido in 2006. The highest level in the recent survey was 6 becquerels in Ibaraki Prefecture, while elevated strontium 90 amounts were also found in Gunma, Yamagata, Saitama, Iwate, Kanagawa, Chiba and Akita prefectures, as well as Tokyo.