Published on Thursday, November 17, 2011 by the Japan Times

http://www.japantimes.co.jp/text/nn20111117x2.html

by Mizuho Aoki

Radioactive cesium from the crippled Fukushima No. 1 nuclear plant may have reached as far as Hokkaido, Shikoku and the Chugoku region in the west, according to a recent simulation by an international research team.

Large areas of eastern and northeastern Japan were likely contaminated by the plant, with concentrations of cesium-137 exceeding 1,000 becquerels per kilogram of soil in some places, says the study, which was posted Monday on the website of the National Academy of Sciences.

Researchers for the U.S.-based organization said the study, which was based on partial data readings, is the first to estimate potential cesium contamination across the country. But they also played down the incident's impact on the three distant regions.

"The levels are not something that should raise concerns over agricultural production or human health," Ryugo Hayano, chairman of the physics department at the University of Tokyo, said in an email interview with The Japan Times.

The simulation indicated that eastern Hokkaido may have been contaminated with up to 250 becquerels per kilogram of cesium-137, while Shikoku and Chugoku were likely tainted with up to 25 becquerels .