Nearly half of children near Fukushima plant absorbed radiation

August 18, 2011

IWAKI, Fukushima Prefecture--A survey of more than 1,000 children and babies living near the quake-stricken Fukushima No. 1 nuclear power plant has produced an alarming finding: 45 percent of them suffered internal exposure to radiation following the accident there.

Most children absorbed relatively low levels of radiation in their thyroid glands, according to officials who explained the results to residents in Iwaki, Fukushima Prefecture, on Aug. 17.

Tests conducted in Iwaki city, Kawamata town and Iitate village between March 24 and 30 found that 26 percent of under-16s absorbed 0.01 microsievert per hour, while 11 percent absorbed 0.02 microsievert per hour. At least one child recorded radiation of 0.10 microsievert per hour, but officials said that level did not pose a health risk.

During a one-on-one consultation session, a woman who had received a letter from the government saying her 14-year-old son had an internal exposure reading of 0.01 microsievert per hour asked the officials whether it was safe for her family to continue living in Iwaki.

An official responded that radiation levels were low in the city, but said she should be careful of grass and roadside ditches.

"The meeting did not answer my questions or eliminate my anxieties at all," she said. She complained that the officials' explanations were no more helpful than what is available on the Internet and other sources of information.

Her son, who also attended the meeting, said: "The figure is not zero because my body has taken in radioactive materials. I would like to be told whether I am OK or not."

Examinations were conducted on about 1,150 children aged 15 or younger, including babies under 1 year old. Data was obtained for 1,080 children.

In 55 percent of cases, no internal exposure was detected.

At the time of the tests, the Nuclear Safety Commission of Japan said detailed examinations would be required if internal exposure levels reached 0.20 microsievert per hour.

The standard was based on the assumption that residents had inhaled radioactive materials gradually over 12 days from March 12, when an explosion shook the nuclear plant and released radioactive materials a day after the Great East Japan Earthquake struck.

But the Japan Atomic Energy Agency and other organizations have since found that large amounts of radioactive iodine were released over four or five days from March 12.

The finding shows that children's internal organs and tissues may have been exposed to much higher radiation levels during that period than was initially assumed.

Iodine-131, for example has a half-life of around five to seven days, meaning that some children may have been exposed to levels of radiation that would require detailed examination.

Radioactive iodine can develop into cancer if large amounts are accumulated in the thyroid gland, and children are particularly vulnerable. The thyroid gland produces hormones related to metabolism and growth from iodine in the body.

The Nuclear Safety Commission of Japan is also not planning to reflect the International Atomic Energy Agency's new stricter standards for taking medications to protect thyroid glands from internal exposure.

The meeting in Iwaki on Aug. 17 was held after residents pressed the government to provide detailed explanations about the survey. Officials had previously said there would be no health problems, but failed to offer figures to back up that statement. About 50 residents attended the meeting in Iwaki.

The Fukushima prefectural government plans to conduct lifelong screening for thyroid gland cancer on about 360,000 children in the prefecture who were 18 or younger on April 1.

The inspections will start as early as October, and initial ultrasound examinations will be carried out by March 2014. These children will undergo ultrasonography once every two years until they turn 20 and once every five years for the rest of their lives.

When lumps and other suspected symptoms are detected, children will receive detailed examinations, including blood tests.

Separate studies of internal exposure started in late June, covering all 2 million residents of Fukushima Prefecture. In preliminary examinations, internal exposure levels were measured using whole-body counters for about 180 residents of Iitate, Kawamata and other areas where high radiation levels were detected.

Initial estimates are that all residents' internal radiation levels over several decades will not exceed 1 millisievert per person, officials say.

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The government document outlining the results of internal exposure examinations conducted in March (The Asahi Shimbun)

The government document outlining the results of internal exposure examinations conducted in March (The Asahi Shimbun)

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  • The government document outlining the results of internal exposure examinations conducted in March (The Asahi Shimbun)
  • An official explains the results of internal exposure examinations in Iwaki, Fukushima Prefecture, on Aug. 17. (The Asahi Shimbun)

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