Fukushima Crisis Is Still Hazy
Fukushima Power Plant
EMF Protection Devices
Magnetic Field Detector
September 7, 2011
By David Cyranoski,
Geoff Brumfiel and Nature magazine
Tatsuhiko Kodama began his 27 July
testimony to Japan's parliament with what he knew. In a
firm, clear voice, he said that the Radioisotope Center of
the University of Tokyo, which he heads, had detected
elevated radiation levels in the days following the meltdown
of three reactors at the Fukushima Daiichi nuclear power
station. But when it came to what wasn't known, he became
angry. "There is no definite report from the Tokyo Electric
Power Company or the government as to exactly how much
radioactive material has been released from Fukushima!" he
shouted.
Kodama's impassioned speech was posted on YouTube in late
July and has received nearly 600,000 views, transforming him
into one of Japan's most visible critics of the government.
But he is not alone. Almost six months after an earthquake
and tsunami triggered the meltdowns, other researchers say
that crucial data for understanding the crisis are still
missing, and funding snags and bureaucracy are hampering
efforts to collect more. Some researchers warn that, without
better coordination, clean-up efforts will be delayed, and
the opportunity to measure the effects of the worst nuclear
accident in decades could be lost. Kodama and a handful of
Japanese scientists have become so frustrated that they are
beginning grassroots campaigns to collect information and
speed the clean-up.
Since the crisis began, the Tokyo Electric Power Company
and the Japanese government have churned out reams of
radiation measurements, but only recently has a full picture
of Fukushima's fallout begun to emerge. On 30 August, the
science ministry released a map showing contamination over a
100-kilometer radius around the plant. The survey of 2,200
locations shows a roughly 35-kilometer-long strip northwest
of the plant where levels of caesium-137 contamination seem
to exceed 1,000 kilobecquerels per square metre. (After the
1986 Chernobyl disaster in Ukraine, areas with more than
1,480 kilobecquerels per square metre were permanently
evacuated by the Soviet authorities. In Japan, the
high-radiation strip extends beyond the original forced
evacuation zone, but falls within a larger 'planned
evacuation zone' that has not yet been completely cleared.)
Exposure estimates
Japan's Nuclear and Industrial Safety Agency has also
published new estimates of the total radiation released in
the accident, based on models that combine measurements with
what is known about the damage to the reactors. The latest
figures, reported to the International Atomic Energy Agency
in June, suggest that the total airborne release of
caesium-137 amounts to 17% of the release from Chernobyl
(see
map). The government estimates that the total radiation
released is 7.7 × 1017 becquerels, 5–6% of the
total from Chernobyl.
Yet "there are still more questions than definite
answers", says Gerald Kirchner, a physicist at Germany's
Federal Office for Radiation Protection in Berlin. High
radiation levels make it impossible to directly measure
damage to the melted reactor cores. Perhaps the greatest
uncertainty is exactly how much radiation was released in
the first ten days after the accident, when power outages
hampered measurements. Those data, combined with
meteorological information, would allow scientists to model
the plume and make better predictions about human exposure,
Kirchner says.
Several measurements suggest that some evacuees received
an unusually high dose. Five days after the crisis began,
Shinji Tokonami, a radiation health expert at Hirosaki
University, and his colleagues drove several hundred
kilometres from Hirosaki to Fukushima City, taking radiation
measurements along the way. The results indicate that
evacuees from Namie, a town some 9 kilometres north of the
plant, received at least 68 millisieverts of radiation as
they fled, more than three times the government's annual
limit (http://dx.doi.org/10.1038/srep00087).
The dose is still safe, says Tokonami. Gerry Thomas, a
radiation health expert at Imperial College London, adds
that radiation exposures from Fukushima were far lower than
those from Chernobyl. "Personally, I do not think that we
will see any effects on health from the radiation, but do
expect to see effects on the psychological well-being of the
population," she says.
But Kodama says that residents of Namie and other towns
inside the evacuation zone could have been better protected
if the government had released its early models of the
plume. Officials say they withheld the projections because
the data on which they were based were sparse.
Hotspots
Many questions also remain about the radiation now in the
environment. The terrain around Fukushima is hilly, and
rainwater has washed the fallout into hotspots, says Timothy
Mousseau, an ecologist at the University of South Carolina
in Columbia who recently travelled to the Fukushima region
to conduct environmental surveys. The plant, located on the
Pacific coast, continues to spew radionuclides into the
water, adds Ken Buesseler, an oceanographer from Woods
Hole Oceanographic Institution in Massachusetts. During a
cruise in mid-July, his team picked up low-level radiation
more than 600 kilometres away. Ocean currents can
concentrate the fallout into hotspots something like those
on land, making the effect on marine life difficult to
gauge.
Gathering more data is a struggle, say researchers.
Tokonami says that overstretched local officials are
reluctant to let his team into the region for fear that it
will increase their workload. Buesseler and Mousseau add
that Japan's famed bureaucracy has made it difficult for
outside researchers to carry out studies. Funding has also
been a problem. To complete his cruise, Buesseler turned to
the Gordon and Betty Moore Foundation for a $3.5-million
grant. Mousseau got a biotech company to sponsor his trip
and has since found funding through the Samuel Freeman
Charitable Trust.
Some Japanese scientists have grown so frustrated with
the slow official response that they have teamed up with
citizens to collect data and begin clean-up. Because
radiation levels can vary widely over small distances, the
latest government maps are too coarse for practical use by
local people, says Shin Aida, a computer scientist at
Toyohashi University of Technology. Aida is proposing a more
detailed map-making effort through 'participatory sensing'.
Using the peer-to-peer support website 311Help (http://311help.com),
Aida plans to have people gather samples from their homes or
farms and send them to a radiation measuring centre, where
the results would be plotted on a map.
Kodama, meanwhile, is advising residents in Minamisoma, a
coastal city that straddles the mandatory evacuation zone.
Minamisoma has set aside ¥960 million ($12.5 million) for
dealing with the nuclear fallout, and on 1 September it
opened an office to coordinate the effort. "We needed to
find out what's the most efficient and effective way to
lower the risk," says one of the leading officials, Yoshiaki
Yokota, a member of the local school board. The first job is
to collect and bury soil at schools. Residents have learned
to first roll the soil in a vinyl sheet lined with zeolite
that will bind caesium and prevent it from seeping into the
groundwater.
Farther northwest, in the city of Date, decontamination
efforts are moving from schools to nearby peach farms. On 31
August, some 15 specialists started removing the top
centimetre of soil at the farms with a scoop or with suction
machines, trying not to damage the peach trees' roots. They
hope to lower the radiation enough to produce marketable
fruit next year.
After a sluggish start, the central government is
launching two pilot clean-up projects for the region. One
will focus on areas like Minamisoma, where radiation is less
than 20 millisieverts per year on average but includes some
hotspots. The other will look at 12 sites of radiation of
more than 20 millisieverts per year.
Researchers are hopeful that the chaos immediately after
the crisis will soon give way to a sharper picture of the
fallout and its toll. The United Nations Scientific
Committee on the Effects of Atomic Radiation (UNSCEAR),
which conducted many studies after the Chernobyl disaster,
is working with Japanese officials to collate the stacks of
data collected since the crisis began. UNSCEAR is also
studying the environmental effects of the accident and the
exposure of workers and evacuees, and aims to have an
interim report ready by next summer.
Clean-up is the top priority, but Fukushima also offers a
unique research opportunity, says Mousseau, who has worked
extensively at Chernobyl. Because of Soviet secrecy,
researchers missed a crucial window of opportunity in
studying the Ukrainian crisis. "Japan offers us an
opportunity to dig in right off the bat and really develop a
profound understanding," he says.
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