Fallout levels twice estimate: study
The Fukushima nuclear accident released double the amount of cesium-137 into the atmosphere than the government initially estimated, reaching 40 percent of the total emitted during the Chernobyl disaster, a preliminary report said.
The estimate of much higher levels of cesium-137 comes from a worldwide network of sensors. Report coauthor Andreas Stohl, of the Norwegian Institute for Air Research, said the government estimate came only from data in Japan and didn't include emissions blown out to the Pacific Ocean.
Cesium-137 is considered harmful because it can remain in the environment for decades, releasing cancer-causing radiation. The report did not consider the health implications of the emissions.
The long-term effects of the nuclear accident are unclear due to the difficulty in measuring the amount of radiation people were exposed to.
Stohl said estimating emissions is such an inexact science that finding twice the amount of cesium isn't considered a major difference. He noted that some previous estimates are higher than his.
The journal Atmospheric Chemistry and Physics posted the report online for comment, but the study has not yet completed a formal review by experts in the field or been accepted for publication.
In the summer, the government estimated that the meltdowns at the Fukushima No. 1 nuclear plant released 15,000 terabecquerels of cesium.
The new report by Stohl and his coauthors estimates the crippled plant spewed about 36,000 terabecquerels from the start of the crisis on March 11 through April 20. That's about 42 percent of the cesium-137 estimated to have been released during the Chernobyl catastrophe, the report said.
About a fifth of the cesium-137 fell on land, while most of the rest fell into the Pacific. Only about 2 percent of the fallout fell on land outside Japan, the report concluded.
Experts have no firm projections about how many cases of cancer could result as they're still trying to determine what doses people were exposed to. Some radiation from the accident has been detected in Tokyo and as far away as the United States, but experts say they don't expect residents there to experience significant health problems.
Still, concern about radiation remains strong in Japan. Many parents of small children in Tokyo worry about the discovery of radiation hot spots, even though government officials say they don't pose a health risk. And former Prime Minister Naoto Kan has said the most contaminated areas inside the evacuation zone could be uninhabitable for decades.
Stohl also noted that his study found cesium-137 emissions dropped suddenly from the time workers started spraying water on the spent fuel pool of one of the wrecked reactors, challenging the government's theory that the pool wasn't emitting the substance.
sourcE: JAPANTIMES
The estimate of much higher levels of cesium-137 comes from a worldwide network of sensors. Report coauthor Andreas Stohl, of the Norwegian Institute for Air Research, said the government estimate came only from data in Japan and didn't include emissions blown out to the Pacific Ocean.
Cesium-137 is considered harmful because it can remain in the environment for decades, releasing cancer-causing radiation. The report did not consider the health implications of the emissions.
The long-term effects of the nuclear accident are unclear due to the difficulty in measuring the amount of radiation people were exposed to.
Stohl said estimating emissions is such an inexact science that finding twice the amount of cesium isn't considered a major difference. He noted that some previous estimates are higher than his.
The journal Atmospheric Chemistry and Physics posted the report online for comment, but the study has not yet completed a formal review by experts in the field or been accepted for publication.
In the summer, the government estimated that the meltdowns at the Fukushima No. 1 nuclear plant released 15,000 terabecquerels of cesium.
The new report by Stohl and his coauthors estimates the crippled plant spewed about 36,000 terabecquerels from the start of the crisis on March 11 through April 20. That's about 42 percent of the cesium-137 estimated to have been released during the Chernobyl catastrophe, the report said.
About a fifth of the cesium-137 fell on land, while most of the rest fell into the Pacific. Only about 2 percent of the fallout fell on land outside Japan, the report concluded.
Experts have no firm projections about how many cases of cancer could result as they're still trying to determine what doses people were exposed to. Some radiation from the accident has been detected in Tokyo and as far away as the United States, but experts say they don't expect residents there to experience significant health problems.
Still, concern about radiation remains strong in Japan. Many parents of small children in Tokyo worry about the discovery of radiation hot spots, even though government officials say they don't pose a health risk. And former Prime Minister Naoto Kan has said the most contaminated areas inside the evacuation zone could be uninhabitable for decades.
Stohl also noted that his study found cesium-137 emissions dropped suddenly from the time workers started spraying water on the spent fuel pool of one of the wrecked reactors, challenging the government's theory that the pool wasn't emitting the substance.
sourcE: JAPANTIMES