Fukushima radiation release higher than thought

NEW YORK – The Fukushima nuclear disaster released twice as much of a radioactive substance into the atmosphere as Japanese authorities estimated, reaching 40 percent of the total from Chernobyl, a preliminary report says.

The estimate of much higher levels of radioactive cesium-137 comes from a worldwide network of sensors. Study author Andreas Stohl of the Norwegian Institute for Air Research says the Japanese government estimate came only from data in Japan, and that would have missed emissions blown out to sea.

The study did not consider health implications of the radiation. Cesium-137 is dangerous because it can last for decades in the environment, releasing cancer-causing radiation.

In a telephone interview, Stohl said emission estimates are so imprecise that finding twice the amount of cesium isn’t considered a major difference. He said some previous estimates had been higher than his.

The journal Atmospheric Chemistry and Physics posted the report online for comment.

Last summer, the Japanese government estimated that the March 11 Fukushima accident released 15,000 terabecquerels of cesium. Terabecquerels are a radiation measurement. The new report from Stohl and co-authors estimates about 36,000 terabecquerels through April 20. That’s about 42 percent of the estimated release from Chernobyl, the report says.