(Adds mayor comment, discovery of bottles as source of
By Yoko Kubota
TOKYO Oct 13 A radiation hotspot has been
detected in Tokyo seven months into Japan's nuclear crisis, but
local officials said on Thursday high readings appeared to be
coming from mystery bottles stored under a house, not the
tsunami-crippled Fukushima atomic plant.
The Fukushima Daiichi nuclear power plant, struck by a
devastating quake and tsunami in March, has released radiation
into the atmosphere that has been carried by winds, rain and
snow across eastern Japan.
Officials in Setagaya, a major residential area in Tokyo
about 235 km (150 miles) southwest of the plant, said this week
it found a radioactive hotspot on a sidewalk near schools,
prompting concerns in the country's most populated area far from
the damaged nuclear plant.
The radiation measured as much as 3.35 microsieverts per
hour on Thursday, higher than some areas in the evacuation zone
near the Fukushima plant, the centre of the world's worst
nuclear disaster since Chernobyl 25 years ago.
But the local government found several bottles under the
floor of a nearby house emitting high levels of radiation.
"A measuring device, when pointed at them, showed very high
readings. Radiation levels were even exceeding the upper limit
for the device," Setagaya Mayor Nobuto Hosaka told a news
Officials from the Education Ministry are now looking into
the matter, including the contents of the bottles.
Public broadcaster NHK said no one had been living in the
house in question.
The city of Funabashi, near Tokyo, said that a citizens'
group had measured a radiation level of 5.8 microsieverts per
hour at a park, but that the city's own survey showed the
highest reading at the park was a quarter of that level.
Radiation levels in the 20 km radius evacuation zone around
the Fukushima Daiichi plant ranged from 0.5 to 64.8
microsieverts per hour, government data showed this week.
About 80,000 residents have evacuated this zone. A
microsievert quantifies the amount of radiation absorbed by
In Yokohama, also near Tokyo, radioactive strontium-90,
which can cause bone cancer and leukaemia, was detected in soil
taken from an apartment rooftop, media reported.
Strontium has been detected within an 80 km zone around the
Fukushima Daiichi plant, but this is the first time it has been
found in an area so far away, local media added.
Radiation exposure from natural sources in a year is about
2,400 microsieverts on average, the U.N. atomic watchdog says.
Japan's education ministry has set a standard allowing up to
1 microsievert per hour of radiation in schools while aiming to
bring it down to about 0.11 microsievert per hour.
(Additional reporting by Kiyoshi Takenaka; Editing by Yoko
Nishikawa and Nick Macfie)