May 24, 2012
Fukushima Radiation Levels Below Reference Level
The World Health Organization (WHO) said on Wednesday that radiation levels in Japan's Fukushima district are below the reference level for public exposure in all but two areas.
The WHO said in its report that the town of Namie and Itate village, which are located 12 to 18 miles away, were most affected. These towns had doses of radiation levels that reached 10 to 50 millisieverts (mSv).
Neighboring towns reached 1 to 10 mSv, while other areas were as low as 0.1 to 10 mSv, according to the report. People are exposed on average to around 2 mSv of radiation a year from their natural environment, while the single-year limit for occupational exposure of workers is 50 mSv.
According to WHO, the rest of the world received an estimated 0.01 mSv dose of radiation during the year after the March 11, 2011 tsunami. This figure is considered to be "very small," the WHO said.
The report said radiation doses received beyond the first year are likely to be lower than the levels reached after the 1996 Chernobyl catastrophe.
WHO said environmental data showed a greater influence of a shorter-lived radionuclide than longer-lasting ones.
During the Chernobyl disaster, about 30 percent of the lifetime dose of radiation was delivered during the first year, and 70 percent in the first 15 years.
The 1996 disaster has sparked more interest lately as a horror movie known as Chernobyl Diaries opens in theaters this weekend. During the movie, six tourists hire a tour guide to take them to the former home of the workers of the Chernobyl nuclear reactor, where they find radiation has affected people who remained in the area.
In the Fukushima district, the radiation was mostly received through ground deposits, compared to other places in Japan where it is received through food ingestion.
A U.N. scientific committee said in a separate report that several workers at the plant had irradiated skin after contamination.
"Six workers have died since the accident but none of the deaths were linked to irradiation," said a statement issued by the United Nations Scientific Committee on the Effects of Radiation (UNSCEAR).
UNSCEAR Chairman Wolfgang Weiss said in a statement that the agency is hoping to evaluate irradiation levels for about 2 million people living in Fukushima prefecture at the time of the March 11 reactor accident.
According to Weiss, UNSCEAR has information about measurements made on the thyroids of over 1,000 children in the area.
Tokyo Electric Power (TEPCO), the operator of the Fukushima plant, said meltdowns at three Fukushima reactors released about 900,000 terabecquerels of radioactive substances into the air after the disaster. This is 2-1/2 times the amount of the first estimate made by Japan's Nuclear and Industrial Safety Agency back in April last year.
TEPCO said its estimate is based on measurements suggesting the amount of iodine-131 release by the nuclear accident was three times higher than previous estimates. Iodine-131 is a radioactive substance produced by fission that takes place inside a nuclear reactor.
Officials believe it could take up to 30 years to decommission the Fukushima reactors after the March 11 event left them crippled.
The Fukushima Daiichi plant was hit by a series of hydrogen explosions and meltdowns after power and cooling systems were cut off by the tsunami.
About 160,000 people were forced to evacuate the area after the incident, and about 50 square miles were blocked off to public access.
UNSCEAR's paper on how much radiation was emitted by the plant will be released in May 2013. It will be the first global and independent assessment of the Fukushima nuclear accident.