Nonradioactive iodine pills of the type distributed in a shelter in Miharumachi, Fukushima Prefecture, are pictured Sunday.Some municipal governments in Fukushima Prefecture distributed pills containing nonradioactive iodine without waiting for the central government's go-ahead, The Yomiuri Shimbun has learned.
The municipal governments decided to distribute the pills, which can be used to protect the thyroid gland from radiation, after relatively high levels of radiation were observed in several locations after a series of accidents at the Fukushima No. 1 nuclear power plant.
Nuclear experts said the radiation levels detected pose no risk to human health.
Premature distribution of the medicine presents the risk of people taking it without needing to. It also risks depleting stocks, meaning the medicine could be in short supply if administering it became necessary.
Under central government policy, iodine pills should in principle be distributed at the time of evacuation, and taken under the supervision of medical personnel.
But a large number of fearful residents in Fukushima Prefecture were desperate to obtain iodine pills, and some municipal governments accepted their requests.
The municipal governments in question are those of Tomiokamachi, Iwaki and Miharumachi.
Tomiokamachi is within a 20-kilometer radius of the troubled power plant, the area to which evacuation orders were issued. Iwaki is within the range of 20 to 30 kilometers from the plant, where residents have been instructed to stay indoors. Miharumachi is outside the elevated-risk zone.
The three municipal governments distributed iodine pills to a total of at least 157,000 people.
The Miharumachi government advised residents to take the medicine. A woman in her 50s in Miharumachi said she let her son take the medicine immediately because the government had instructed people to do so.
But she later heard taking the medicine had not been necessary at the time. She said: "I did it because I expected the medicine to have an effect. Now I know it was useless."
The central and prefectural governments apparently were unable to avoid confusion amid the massive exchange of information between them.
Hidehiko Nishiyama, a senior official of the Nuclear and Industrial Safety Agency, said Saturday night, "On the morning of March 16, we instructed the prefectural government to give iodine medicine to people who were evacuating from inside the 20-kilometer zone."
The evacuations had been completed by shortly after noon on March 15, however.
A prefectural government division chief in charge of the issue said, "We didn't [hand out the iodine pills] because we judged it was useless to let people take the medicine after they had already evacuated."
A NISA official said, "We did decide to give people the medicine as a preventative step, but as it turned out nobody actually received the pills."
On Saturday, Nagasaki University Prof. Shunichi Yamashita, who is also the head of the World Health Organization's Collaboration Center for Research on Radiation Emergency Medicine, visited the prefectural government's disaster headquarters.
He said to reporters: "Information about radiation risks has not been correctly communicated. Under the current levels, administering iodine pills is unnecessary."
Medicine containing nonradioactive iodine is kept by authorities for use in case of a nuclear accident.
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Iodine not sure-fire defense
By Masashi Yoshida and Masae Honma / Yomiuri Shimbun Staff Writers
Ingesting nonradioactive iodine protects people from harmful effects of exposure to radiation.
Iodine is essential for the production of the thyroid hormone, and thus iodine in the body is absorbed by the thyroid gland.
If radioactive iodine discharged from a nuclear reactor enters the human body, such as via air or food, it accumulates in the thyroid gland and remains radioactive. It heightens the risk of cancer.
Nonradioactive iodine is absorbed by the thyroid gland in the same way. Therefore, preemptively "filling" the thyroid gland with nonradioactive iodine will prevent the gland from absorbing harmful radioactive iodine.
If radioactive iodine then does enter the body, it will not accumulate and will be passed out of the body.
Timing is important to maximize the efficacy of iodine medicine. Medical experts say the medicine remains effective for about 24 hours after ingestion.
Taking the medicine within about eight hours of exposure to radioactive iodine can still reduce the quantity absorbed by the thyroid gland by up to 40 percent.
According to a guideline of the Nuclear Safety Commission, taking the medicine is advised for people aged under 40. Those aged over 40 have a low risk of developing thyroid cancer even if exposed to radiation.
But the nuclear disaster headquarters in the disaster zone allowed people aged 40 or older who wanted to take the medicine to do so.
Important to remember is that nonradioactive iodine medicine does not provide guaranteed protection from radiation. It does not protect from the health risks posed by other radioactive elements, such as cesium.
Some people cannot take the medicine, such as those who have an iodine intolerance. Reported side effects of the medicine include nausea and diarrhea.
Therefore, the central government guideline stipulates people should take the medicine only if necessary--that is, at the time of evacuation.
Some people wrongly believe that mouthwashes and disinfectant agents containing iodine can help prevent health damage caused by radiation. Such products have no such preventative effects, and can be harmful if swallowed. Wakame seaweed and kelp contain nonradioactive iodine, but in quantities far too small to have preventative effects.
(Mar. 22, 2011)
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