Wednesday, 9 October 2013
High radiation levels found at possible Olympic sites; Tokyo dismisses data 東京オリンピックの開催予定地に高濃度の放射能汚染が検出されたが、東京都はそのデーターを無視
(Source) http://ajw.asahi.com/article/0311disaster/fukushima/AJ201310080051
By SHOJI NOMURA/ ASAHI SHIMBUN WEEKLY AERA
A citizens group said it measured high radiation levels at candidate venues for the 2020 Tokyo Olympics, but the metropolitan government disputes the data and the International Olympic Committee has shown little interest.
The group said some of the potential venues for the Summer Games had radiation levels exceeding the Tokyo metropolitan government’s standards for decontamination: 0.23 microsievert per hour 1 meter above ground or a hot spot that measures at least 1 microsievert per hour higher than the surrounding areas.
The site with the highest airborne radiation level was Yumenoshima Stadium in Tokyo’s Koto Ward. Located within Yumenoshima Park, the site has a nearby canal where yachts are anchored.
For the 2020 Games, the stadium and the 12 adjacent baseball fields will be plowed over. Facilities are planned there for equestrian events, such as dressage and jumping.
Group members said a reading of 0.484 microsievert per hour was detected 5 centimeters above ground in shrubs next to an entrance on the southern side of the stadium. They said they did not know why such a high reading was found.
Soil from the site had 3,040 becquerels of radioactive cesium per kilogram.
Other sites with comparatively high radiation levels 5 cm above ground were the Tokyo Metropolitan Gymnasium in Shibuya Ward, the projected venue for table tennis, and Yoyogi Gymnasium in the same ward, where the handball competition will be held.
The Uminomori cross country course near Tokyo Bay that is being considered for the equestrian eventing competition had a reading of 0.29 microsievert per hour at a height of 1 meter, the group said.
“The central and Tokyo metropolitan governments have not informed athletes and audiences around the world about data concerning possible radiation exposure,” said Takehiko Tsukushi, 70, who formed the citizens group. “If that is the case, I felt it was our moral responsibility as citizens to conduct the measurement and inform people, regardless of whether they support or oppose having the Olympics in Tokyo.”
The group measured radiation levels at candidate venues in Tokyo, Kanagawa and Saitama prefectures, but it could not cover all 37 sites that could host Olympic events.
The group did not take measurements at the candidate venues in Hokkaido and Miyagi Prefecture because of their distance from Tokyo. And it could not measure radiation levels at the Uminomori mountain bike course because it is still under construction.
After the 2011 meltdowns at the Fukushima No. 1 nuclear plant, Tsukushi, who lives in Tokyo’s Kita Ward, became a member of a group that sought to protect the ward’s children from radiation.
In late March this year, he began seeking members for a new group to measure radiation levels at Olympic venues. Over 14 days in April and May, 92 people of various ages and occupations took radiation measurements using their personal dosimeters.
The group selected a maximum of nine spots above asphalt and grass at each site. Three measurements were taken at each spot at heights of 5 centimeters and 1 meter. The median measurement was used to reduce error.
While hot spots have been detected mainly in eastern Tokyo, the group found readings close to 0.15 microsieverts per hour in a number of other locations, including Chofu in northwestern Tokyo and the Saitama Prefecture cities of Asaka and Kawagoe.
“We believe the data shows that radioactive materials have spread throughout the Kanto region, and that there are some hot spots within that wider area,” Tsukushi said.
The Tokyo metropolitan government’s standard for decontamination 1 meter above ground is based on the recommendation of the International Commission on Radiological Protection (ICRP), which set maximum annual radiation exposure levels for citizens at 1 millisievert , excluding background radiation and radiation from medical treatment.
[...]
Before the Fukushima nuclear accident, radiation readings at the Shinjuku institute were between 0.028 and 0.079 microsievert per hour, or levels similar to current measurements.
[...]
Radiation levels can increase over dirt that absorbs cesium or in grass. Other areas where cesium tends to concentrate include roadside ditches or under gutters where rainwater containing cesium may flow.
Noguchi said such conditions may exist at some Olympic venue sites.
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However, the Tokyo metropolitan government continues to insist there is no need for decontamination for isolated cases because those areas do not fall under the guidelines established by the decontamination standards.
During news conferences to promote Tokyo’s Olympic bid, Tokyo Governor Naoki Inose repeatedly said: “Radiation levels in Tokyo are no different from those in New York, London and Paris. There is no problem.”
Noguchi said the Tokyo metropolitan government should measure radiation levels at the venues and release the data to back up Inose’s argument.
“Saying there is no problem without even measuring for radiation is the same response as the Democratic Party of Japan government immediately after the Fukushima nuclear accident,” Noguchi said. “As host nation for the Olympics, it is imperative that radiation levels at the venues be released to the world.”
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