Nearly half the children surveyed in three towns near the stricken Fukushima Daiichi nuclear plant received low-grade internal exposure to radiation during the early days of the accident there, the government said Thursday, fueling concerns about long-term health effects on local residents.
Nearly half the children surveyed in three towns near the stricken
Fukushima Daiichi nuclear plant received low-grade internal exposure to
radiation during the early days of the accident there, the government said
Thursday, fueling concerns about long-term health effects on local residents.
The government in late March tested 1,150 children in the three towns located
outside of the government mandatory evacuation zones and said that all of them
cleared its health standard. After
Fukushima
parents and radiation experts demanded more details, the government revealed
this week that 45% of the children were exposed to radiation, albeit at low
levels.
While the government has released a few reports on radiation exposure for
workers at the
Fukushima
complex, this is the first time officials have made public the results for
tests to detect internal exposure on residents near the reactors. Internal
radiation, which enters the human body through breathing in contaminated air or
consuming contaminated food or drinks, can have a greater health effect than what's
known as external radiation, in which radiation is confined to the surrounding
environment.
Since the accident, the government has tested 219,000 residents for external
exposure. Some initially showed elevated levels, but once clothes were removed
and showers were taken, none had showed results high enough to warrant health
concerns, according to a NISA statement. The government has promised to do
further tests in the coming weeks on potentially affected populations.
A spokesman for the Nuclear and Industrial Safety Agency, the main nuclear
regulatory body, said Thursday that the doses the
Fukushima
children received were below the levels at which health effects become a
concern. Children, particularly younger ones, are more susceptible to the
effects of radiation, facing higher risks than adult of developing thyroid
cancer later in life, experts say.
One independent expert, Yoshio Hosoi, a professor at the Research Institute for
Radiation Biology and Medicine at
Hiroshima
University
, said
in an interview that, assuming the results reported are accurate, "I think
the possibility of these children developing thyroid cancer is extremely
low."
However, he raised some questions about the government's testing methodology,
saying that officials didn't conduct the tests quickly enough after the initial
exposure to measure radioactive elements known to disintegrate rapidly, such as
iodine 132 and tellurium. NISA officials couldn't be reached late Thursday for
comment.
The latest news follows a series of reports raising concerns about the
protection against radiation exposure provided by the government to local
residents during the days and weeks following the accident. For example,
government officials had data a few days after the accident indicating that
Iitate-one of the three towns where the children were tested - had become what
they later called a nuclear "hot spot" with elevated levels of contamination.
But officials didn't order an evacuation until more than a month later,
prompting criticism that the residents were subjected to unnecessary radiation
exposure.
The tests were conducted between March 24 and 30 on the thyroid glands of
children in Iitate, Kawamata and Iwaki-three municipalities located outside of
the government's 20 kilometer evacuation zone established the day after the
March 11 earthquake and tsunami struck the plant. The move came after the
government confirmed in late March its radiation projection system known as
Speedi showed these towns had received relatively large doses of exposure. The
tests were conducted on children ranging in age from infancy to 15 years old.
According to the breakdown of the test results--first revealed to some
Fukushima
parents on Wednesday--55% of the children showed "zero" exposure to
radiation. Another 26% were found to have received 0.01 microsievert per hour,
well below 0.2 microsievert per hour that the government considers a health
risk.
The exposure level was 0.02 microsievert for 11% of the children, 0.03
microsievert for 4.7%, and 0.04 microsievert for 1.4%. The highest dose of 0.1
microsievert was found in a single individual, the NISA spokesman said.
"The health conditions of these children will be monitored very closely
over the long term," the spokesman said, adding that
Fukushima
prefecture has already started a far-reaching health monitoring program.
Fukushima
prefecture will send out
questionnaires to survey all of its 2 million residents later this month, and
plans to monitor over the next three decades the 200,000 considered most at
risk.
Meanwhile, all of the 28,000 residents in three different municipalities deemed
high risk were offered opportunities to receive a whole body scan to detect
internal radiation.
Some 2,000 have taken the scan, but none showed results that raised health
concerns, the
Fukushima
spokesman said.
In addition, all
Fukushima
residents 18 years-old or younger will go through a test of the thyroid gland
over the next three years, and then be tested every other year thereafter. Mr.
Hosoi of
Hiroshima
University
said
children found to have received exposure through the March tests should be
examined once a year.
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