海江田経済産業相は２２日の閣議後の記者会見で、東京電力福島第一原子力発電所事故について東電と経産省原子力安全・保安院が個別に開いている記者会見を、１日１度は両者の共同記者会見とする方針を明らかにした。
２５日から実施する。政府と東電が設置した「福島原子力発電所事故対策統合本部」の記者会見と位置付け、本部事務局長の細野豪志・首相補佐官や東電、保安院の担当者が出席する。
東電と保安院が、それぞれ１日に数度開く記者会見で、説明内容が食い違うケースがあるからだ。
共同記者会見は、原則として毎日夕方、東電本店で行う。原子力安全委員会や文部科学省などの担当者も同席する。
ただ、東電と保安院は当面の間、１日数度の個別記者会見も従来通り続ける方針だ。
（2011年4月22日23時30分 読売新聞）
Showing posts with label erroneous information. Show all posts
Showing posts with label erroneous information. Show all posts
Saturday, April 23, 2011
Saturday, April 16, 2011
16/04 World critical of Japan's failure to disclose info
The Yomiuri Shimbun
This is the fifth installment in a series focusing on delays in implementing emergency steps by the government and Tokyo Electric Power Co. to deal with the unprecedented nuclear crisis at the Fukushima No. 1 nuclear power plant.
Many countries have grown frustrated with and distrustful of the Japanese government for its poor handling of the Fukushima No. 1 nuclear plant crisis and its failure to disclose relevant information after the earthquake and tsunami of March 11.
What countermeasures will Japan take against tsunami in the future? Also, we need to know the exact details of what's happening with the reactors at the Fukushima No. 1 nuclear plant.
These were just a couple of the grueling questions thrown at the Nuclear and Industrial Safety Agency's Deputy Director General for Nuclear Safety, Koichiro Nakamura, at a small-group session of a review meeting for contracting parties to the Convention on Nuclear Safety in Vienna on April 6.
The session was held to check Japan's compliance with the terms of the treaty. In addition to representatives from the group's 12 member countries, about 200 international representatives and experts attended--an unusually large number.
According to some participants, Japan failed to respond clearly to questions and initially described the situation at the nuclear plant as under control. This remark was later corrected to "We're trying to control it," and "We don't know [exactly what is happening inside the nuclear reactors]."
"I doubt any of the foreign participants were satisfied with Japan's explanation," said a visibly disappointed European diplomat.
A Russian expert was more critical, saying: "If nuclear plants are built on the coast, it's foreseeable that a major tsunami could occur. Despite being a technologically advanced nation, Japan has no robots that can be used at nuclear plants!"
Another European expert described Japan's initial handling of the crisis as problematic, saying, "Damage to one of the reactors may have been less severe if initial measures, such as opening a hole in the reactor building, were taken to prevent hydrogen explosions."
South Korean experts were the most disgruntled. "Despite being neighbors, Japan did not tell us beforehand that it would be discharging contaminated water into the sea. Communication on disaster relief and assistance between [South Korea and Japan] is not good enough," he said.
Tokyo's failure to give Seoul advance warning about discharging radioactive water into the sea became a political issue within South Korea. When a plenary meeting of an extraordinary session of the National Assembly was held in Seoul on April 7, Prime Minister Kim Hwang Sik was questioned by an independent assembly member over the issue. Kim, raising his voice, responded: "I would like to remind you it's not our government that's incompetent. It's the Japanese government."
===
U.S. critical of Japan
There have also been indications that the United States was critical toward the Prime Minister Naoto Kan's administration for its handling of the nuclear crisis.
Apparently John Roos, U.S. Ambassador to Japan, was at times annoyed with the lack of detailed information coming from Japan.
At one point his embassy had difficulty finding out exactly whom to contact over the issue--Tokyo Electric Power Co., the Prime Minister's Office, or concerned ministries--and was therefore unable to determine the assistance Japan needed.
Roos tried to collect relevant information by phoning Chief Cabinet Secretary Yukio Edano, Finance Minister Yoshihiko Noda and other Democratic Party of Japan Diet members he knew personally.
The United States even attempted to gather information independently using a spy satellite and an unmanned surveillance plane, a Global Hawk, possibly indicating a lack of confidence in the Japanese government.
A visiting expert from the U.S. government's Nuclear Regulatory Commission (NRC) was reportedly frustrated with Akihisa Nagashima, a former parliamentary secretary of the Defense Ministry and now a DPJ member in the House of Representatives. At a meeting at TEPCO's head office in Tokyo on March 18, the expert allegedly told Nagashima it was unclear who was actually in charge of managing the crisis.
Yet bilateral cooperation on dealing with the crisis later improved.
On March 20, Kan responded to a request by Nagashima and approved setting up a panel to coordinate views between the two countries.
The panel first convened on March 22 at a governmental facility near the Prime Minister's Office. Defense leaders from both countries, who were already in existing talks, were assigned to work together on relevant issues. At this stage more than 10 days had passed since the original disaster.
The panel initially held daily meetings but has since rescheduled these for every other day. Their duration was later halved from one hour to 30 minutes, indicating some progress has been made in sharing information.
===
Danger hampering cooperation
Cooperation with other countries has not been running so smoothly. The reality is that despite the advances made by many countries in generating nuclear power, no one has a miracle cure for bringing the crisis at the Fukushima nuclear plant under control.
About 20 experts from Areva SA, a French major nuclear reactor maker, arrived in Japan and are now stationed at joint task force headquarters set up at TEPCO and other places.
Since Areva has already operated nuclear fuel reprocessing plants, it is expected to provide TEPCO with the technology to remove contaminated water from the reactors.
Yet according to a TEPCO official, Areva has been unable to act. "It is unsafe for workers because radiation levels [near the nuclear reactors] are too high," he said.
Anne Lauvergeon, chief executive officer of Areva, described the situation as both complicated and unprecedented. She noted the outlook for the plant seemed dismal and that the top priority was to find out what was going on.
(Apr. 16, 2011)
This is the fifth installment in a series focusing on delays in implementing emergency steps by the government and Tokyo Electric Power Co. to deal with the unprecedented nuclear crisis at the Fukushima No. 1 nuclear power plant.
Many countries have grown frustrated with and distrustful of the Japanese government for its poor handling of the Fukushima No. 1 nuclear plant crisis and its failure to disclose relevant information after the earthquake and tsunami of March 11.
What countermeasures will Japan take against tsunami in the future? Also, we need to know the exact details of what's happening with the reactors at the Fukushima No. 1 nuclear plant.
These were just a couple of the grueling questions thrown at the Nuclear and Industrial Safety Agency's Deputy Director General for Nuclear Safety, Koichiro Nakamura, at a small-group session of a review meeting for contracting parties to the Convention on Nuclear Safety in Vienna on April 6.
The session was held to check Japan's compliance with the terms of the treaty. In addition to representatives from the group's 12 member countries, about 200 international representatives and experts attended--an unusually large number.
According to some participants, Japan failed to respond clearly to questions and initially described the situation at the nuclear plant as under control. This remark was later corrected to "We're trying to control it," and "We don't know [exactly what is happening inside the nuclear reactors]."
"I doubt any of the foreign participants were satisfied with Japan's explanation," said a visibly disappointed European diplomat.
A Russian expert was more critical, saying: "If nuclear plants are built on the coast, it's foreseeable that a major tsunami could occur. Despite being a technologically advanced nation, Japan has no robots that can be used at nuclear plants!"
Another European expert described Japan's initial handling of the crisis as problematic, saying, "Damage to one of the reactors may have been less severe if initial measures, such as opening a hole in the reactor building, were taken to prevent hydrogen explosions."
South Korean experts were the most disgruntled. "Despite being neighbors, Japan did not tell us beforehand that it would be discharging contaminated water into the sea. Communication on disaster relief and assistance between [South Korea and Japan] is not good enough," he said.
Tokyo's failure to give Seoul advance warning about discharging radioactive water into the sea became a political issue within South Korea. When a plenary meeting of an extraordinary session of the National Assembly was held in Seoul on April 7, Prime Minister Kim Hwang Sik was questioned by an independent assembly member over the issue. Kim, raising his voice, responded: "I would like to remind you it's not our government that's incompetent. It's the Japanese government."
===
U.S. critical of Japan
There have also been indications that the United States was critical toward the Prime Minister Naoto Kan's administration for its handling of the nuclear crisis.
Apparently John Roos, U.S. Ambassador to Japan, was at times annoyed with the lack of detailed information coming from Japan.
At one point his embassy had difficulty finding out exactly whom to contact over the issue--Tokyo Electric Power Co., the Prime Minister's Office, or concerned ministries--and was therefore unable to determine the assistance Japan needed.
Roos tried to collect relevant information by phoning Chief Cabinet Secretary Yukio Edano, Finance Minister Yoshihiko Noda and other Democratic Party of Japan Diet members he knew personally.
The United States even attempted to gather information independently using a spy satellite and an unmanned surveillance plane, a Global Hawk, possibly indicating a lack of confidence in the Japanese government.
A visiting expert from the U.S. government's Nuclear Regulatory Commission (NRC) was reportedly frustrated with Akihisa Nagashima, a former parliamentary secretary of the Defense Ministry and now a DPJ member in the House of Representatives. At a meeting at TEPCO's head office in Tokyo on March 18, the expert allegedly told Nagashima it was unclear who was actually in charge of managing the crisis.
Yet bilateral cooperation on dealing with the crisis later improved.
On March 20, Kan responded to a request by Nagashima and approved setting up a panel to coordinate views between the two countries.
The panel first convened on March 22 at a governmental facility near the Prime Minister's Office. Defense leaders from both countries, who were already in existing talks, were assigned to work together on relevant issues. At this stage more than 10 days had passed since the original disaster.
The panel initially held daily meetings but has since rescheduled these for every other day. Their duration was later halved from one hour to 30 minutes, indicating some progress has been made in sharing information.
===
Danger hampering cooperation
Cooperation with other countries has not been running so smoothly. The reality is that despite the advances made by many countries in generating nuclear power, no one has a miracle cure for bringing the crisis at the Fukushima nuclear plant under control.
About 20 experts from Areva SA, a French major nuclear reactor maker, arrived in Japan and are now stationed at joint task force headquarters set up at TEPCO and other places.
Since Areva has already operated nuclear fuel reprocessing plants, it is expected to provide TEPCO with the technology to remove contaminated water from the reactors.
Yet according to a TEPCO official, Areva has been unable to act. "It is unsafe for workers because radiation levels [near the nuclear reactors] are too high," he said.
Anne Lauvergeon, chief executive officer of Areva, described the situation as both complicated and unprecedented. She noted the outlook for the plant seemed dismal and that the top priority was to find out what was going on.
(Apr. 16, 2011)
Thursday, April 14, 2011
11/04 Fukushima : un mois d'erreurs de communication
LEMONDE.FR | 11.04.11 | 18h11 • Mis à jour le 14.04.11 | 11h27
Il y a un mois, la terre tremblait au Japon, avant qu'une vague géante n'emporte 13 000 personnes et fasse 14 000 disparus. Le gouvernement japonais, l'opérateur de la centrale Tokyo Electric Power (Tecpo) et l'agence japonaise de sûreté nucléaire ont depuis multiplié les bourdes et les annonces contradictoires.
11 mars. "Un risque de fuite radioactive limitée." Alors que les premières images du séisme font le tour du monde, personne n'a encore les yeux rivés sur Fukushima. Le gouvernement japonais fait état un peu plus tôt d'un "risque de fuite radioactive limitée" à la suite d'une panne du système de refroidissement d'un réacteur de cette centrale
12 mars. Evacuation dans un rayon de 10 km. Une explosion a lieu à la centrale nucléaire de Fukushima. Les premiers rapports sur de forts taux de radioactivité autour du site ont un écho dans la presse. Un niveau de radioactivité 1 000 fois supérieur à la normale a été détecté dans la salle de contrôle du réacteur numéro 1 de Fukushima Dai-Ichi, annonce l'agence de presse Kyodo, citant une commission de sécurité. Le premier ministre japonais, Naoto Kan, demande aux habitants d'évacuer dans un rayon de 10 kilomètres autour de ce site mais dément les chiffres avancés par Kyodo.
A l'époque, l'opinion japonaise reste globalement solidaire du gouvernement et proteste contre le sensationalisme et l'alarmisme exagéré de la presse étrangère.
14 mars. Nouvelle explosion : possibilité d'un rejet de particules "faible".Alors qu'une nouvelle explosion secoue la centrale déjà endommagée, Yukio Edano, le porte-parole du gouvernement, s'empresse d'annoncer que la possibilité d'un "rejet de particules radioactives est faible".
19 mars. Premières craintes autour de l'eau. De l'iode radioactif est détecté dans l'eau du robinet jusqu'à Tokyo. Les habitants sont informés qu'elle n'est dangereuse que pour les nourrissons. Ils ne veulent pas, pour la plupart, céder à la panique.
21 mars. Les épinards ne sont "pas dangereux pour la santé". La nourriture "contaminée", principalement les légumes feuillus, comme les épinards, est retirée du marché. Pourtant, le gouvernement annonce de manière contradictoire que leur consommation n'est pas "pas dangereuse pour la santé".
En colère contre l'absence d'informations concernant les risques liés à la consommation d'aliments, la qualité de l'air et de l'eau, les Japonais commencent à critiquer la presse, notamment sur Twitter.
24 mars. Eau à nouveau potable. L'eau est repassée en "dessous du seuil consommable pour les bébés", annonce le gouvernement. Le gouverneur de Tokyo, Shintaro Ishihara, se rend dans un centre de purification de l'eau et se sert un verre devant les caméras, pour prouver que l'eau n'est pas dangereuse pour la santé. Les Tokyoïtes font toujours le plein de bouteilles d'eau, qui commencent à se faire rare dans les supermarchés.
26 mars. "Nous devrons examiner la gestion de Tepco." Accusé de faire partie du lobby nucléaire et de ne pas être assez sévère avec l'opérateur Tepco, le ministre japonais de l'économie reconnaît du bout des lèvres que "lorsque la situation de crise aura été maîtrisée, nous devrons examiner la gestion de Tepco". Mais les erreurs de communication vont continuer. Des taux d'iode radioactif très élevés sont détectés en mer, malgré les annonces répétées de Tepco et du gouvernement sur l'absence de danger.
31 mars. Les résidents de Fukushima "peuvent être sereins". Tokyo refusetoujours d'élargir la zone d'exclusion, malgré les mesures de radioactivité alarmantes effectuées par l'Agence internationale de l'énergie atomique (AIEA) et Greenpeace. "Je ne pense pas que ce soit quelque chose de nature à exiger une telle action", déclare le porte-parole du gouvernement, Yukio Edano. Les résidents"peuvent être sereins", ajoute un responsable de l'Agence japonaise de sûreté nucléaire, un organisme officiel. Pourtant, le gouvernement se dit toujours "en état d'alerte maximale".
7 avril. Centrale d'Onagawa : fuites d'eau ou basculement ? Le Japon est touché par un nouveau séisme, qui fera quatre victimes. On apprend que la centrale d'Onagawa, plus au nord, a été touchée. Tepco annonce des fuites d'eau, ce qui provoque de nouvelles inquiétudes. On apprend par la suite qu'il ne s'agit pas de fuites mais d'un basculement du trop plein d'eau "faiblement radioactive" au-dessus de la cuve à la suite des secousses – un scénario moins grave.
Le gouvernement lève les interdictions sur les produits frais venus des environs de Fukushima, tandis que plusieurs pays ont arrêté ou fortemement régulé l'importation des produits agricoles en provenance du Japon.
11 avril. Excuses publiques de Tepco. Le gouvernement élargit, sous la pression, la zone d'exclusion à 30 kilomètres autour de la centrale. Masataka Shimizu, le PDG de Tepco, doit se rendre dans la région lundi pour s'excuser des troubles causés aux habitants de la préfecture de Fukushima. Il s'agira de la première apparition publique de M. Shimizu depuis le 13 mars. Le PDG était tombé malade le 16 mars et avait alors pris une semaine d'arrêt de travail.
Wednesday, March 23, 2011
18/03 Experts: Be wary of wild reports, rumors by Yomiuri
The Yomiuri Shimbun
False reports and e-mails have run rampant since last week's deadly earthquake, stoking fear and panicked buying of food and medicine.
Related organizations are calling on the public to act calmly and not be misled by inaccurate information and rumors.
At an evacuation center set up at Kawamata High School in Kawamatamachi, Fukushima Prefecture--about 50 kilometers from the stricken Fukushima No. 1 nuclear power plant--a rumor circulated among town officials before dawn on Tuesday that the disaster response headquarters had issued an order for people to move or stay indoors. The center was established for people evacuated from towns within 20 kilometers of the plant.
Officials of the Namiemachi and Futabamachi municipal governments ran outside without confirming the information and woke up evacuees sleeping in cars outside and urged them to rush into the school's gymnasium. After sunrise that day, however, the evacuation order was proved to be false. The origin of the rumor was not known.
"A radio is the only source of information available [at the school's gym]," a Namiemachi municipal official complained. "We have no TV, and telephone and Internet services are limited. We can't get detailed information about the nuclear power plant, so correct information isn't reaching the evacuees."
A woman from Kitakata, Fukushima Prefecture, received an e-mail Monday from a friend telling her that future rainfall in the area would contain dangerous levels of radiation, so she should be sure to wear a raincoat.
The woman rushed to a number of shops only to find all raincoats sold out.
An official of the Nuclear Safety Technology Center called on the public to keep calm, saying: "Not having direct contact with rain is an effective way [to avoid radiation exposure], but the levels of radiation currently detected in the air do not indicate the possibility that radiation-laced rain will fall."
Also rampant were e-mails recommending the use of gargles that contain iodine, drinking iodine solutions and eating wakame seaweed and kelp shavings as substitutes for stable iodine preparation, an oral medicine that helps prevent physical damage from radioactive iodine.
Sales of gargles at a drugstore in Date, Fukushima Prefecture, shot up after a hydrogen explosion occurred at the Fukushima No. 1 nuclear power plant Saturday. The store sold out by Tuesday evening.
Experts have denounced such information as groundless. A researcher at the National Institute of Radiological Sciences warned that "swallowing a gargle will actually harm your health, and you can't expect desirable effects from eating wakame and things like that."
Likewise, an official of the Nuclear Safety Commission said "eating kelp shavings is not an appropriate way to restrict the accumulation of radioactive iodine in the thyroid gland."
SecureBrain Corp., a Tokyo-based Net security firm, warned against inflammatory mails, saying: "These are typical examples of chain mail, which carry the message 'send this to as many people as possible.' If you believe it and send the information to friends, you'll just fan anxiety."
An official of the Internal Affairs and Communications Ministry urged the public to "confirm information through reliable sources such as media reports and not be misled by chain mails. If you receive a chain mail, you should delete it promptly."
(Mar. 18, 2011)
False reports and e-mails have run rampant since last week's deadly earthquake, stoking fear and panicked buying of food and medicine.
Related organizations are calling on the public to act calmly and not be misled by inaccurate information and rumors.
At an evacuation center set up at Kawamata High School in Kawamatamachi, Fukushima Prefecture--about 50 kilometers from the stricken Fukushima No. 1 nuclear power plant--a rumor circulated among town officials before dawn on Tuesday that the disaster response headquarters had issued an order for people to move or stay indoors. The center was established for people evacuated from towns within 20 kilometers of the plant.
Officials of the Namiemachi and Futabamachi municipal governments ran outside without confirming the information and woke up evacuees sleeping in cars outside and urged them to rush into the school's gymnasium. After sunrise that day, however, the evacuation order was proved to be false. The origin of the rumor was not known.
"A radio is the only source of information available [at the school's gym]," a Namiemachi municipal official complained. "We have no TV, and telephone and Internet services are limited. We can't get detailed information about the nuclear power plant, so correct information isn't reaching the evacuees."
A woman from Kitakata, Fukushima Prefecture, received an e-mail Monday from a friend telling her that future rainfall in the area would contain dangerous levels of radiation, so she should be sure to wear a raincoat.
The woman rushed to a number of shops only to find all raincoats sold out.
An official of the Nuclear Safety Technology Center called on the public to keep calm, saying: "Not having direct contact with rain is an effective way [to avoid radiation exposure], but the levels of radiation currently detected in the air do not indicate the possibility that radiation-laced rain will fall."
Also rampant were e-mails recommending the use of gargles that contain iodine, drinking iodine solutions and eating wakame seaweed and kelp shavings as substitutes for stable iodine preparation, an oral medicine that helps prevent physical damage from radioactive iodine.
Sales of gargles at a drugstore in Date, Fukushima Prefecture, shot up after a hydrogen explosion occurred at the Fukushima No. 1 nuclear power plant Saturday. The store sold out by Tuesday evening.
Experts have denounced such information as groundless. A researcher at the National Institute of Radiological Sciences warned that "swallowing a gargle will actually harm your health, and you can't expect desirable effects from eating wakame and things like that."
Likewise, an official of the Nuclear Safety Commission said "eating kelp shavings is not an appropriate way to restrict the accumulation of radioactive iodine in the thyroid gland."
SecureBrain Corp., a Tokyo-based Net security firm, warned against inflammatory mails, saying: "These are typical examples of chain mail, which carry the message 'send this to as many people as possible.' If you believe it and send the information to friends, you'll just fan anxiety."
An official of the Internal Affairs and Communications Ministry urged the public to "confirm information through reliable sources such as media reports and not be misled by chain mails. If you receive a chain mail, you should delete it promptly."
(Mar. 18, 2011)
23/03 How much radiation is too much radiation?
The Yomiuri Shimbun
There is a lot of erroneous information floating around about radiation contamination, making it important to brush up on the basics so you can know what is really happening.
The government has placed restrictions on some products, including spinach from certain areas, after radioactive isotopes were detected on the produce and in the water supply after a series of accidents at the Fukushima No. 1 nuclear power plant.
It is important to remember that "radiation" refers to a wide variety of radioactive elements.
What effects do these elements have on the human body? How can one prevent exposure and minimize the health risks?
===
It's in the food--can I eat it?
On Monday, government inspectors found levels of radioactive iodine and cesium that exceeded legal limits in spinach, milk and other produce from Tohoku and Kanto.
The radioactive material was leaked from the power plant and scattered by the wind, which carried it to nearby farms, where it adhered to the surface of spinach and pastures where cows were grazing.
Ingesting radioactive isotopes leads to internal exposure to radiation.
The Nuclear Safety Commission has set standards for acceptable levels of radiation in water, milk and produce--excluding root vegetables, such as yams.
The decision to restrict shipments of these items was based on these numerical standards.
For dairy products such as milk, the NSC has determined 300 becquerel of radioactive iodine per kilogram and 200 becquerel of radioactive cesium per kilogram are safe for consumption.
For vegetables, acceptable levels increase to 2,000 becquerel and 500 becquerel, respectively.
Following the detection of high levels of radioactive substances in some agricultural products Monday, the government ordered Fukushima, Ibaraki, Tochigi and Gunma prefectures to halt shipments of spinach and kakina greens. It also ordered Fukushima Prefecture to halt milk shipments for the time being.
"Even if people eat these products, there will be no immediate effect," Chief Cabinet Secretary Yukio Edano said. "We have imposed the restrictions in case the radiation leak becomes protracted."
Food safety expert Hideaki Karaki, professor emeritus at the University of Tokyo, said: "As it stands, the radiation levels that have been detected in food present no danger. But in all likelihood, many consumers would refuse to buy the products even if they were shipped, so factoring in distribution costs, this restriction was unavoidable."
"Moving forward, similar incidents and harmful rumors need to be nipped in the bud by disclosing correct information, and farmers need to be properly compensated for their losses," he said.
In Iitatemura, Fukushima Prefecture, radioactive iodine was detected in the water supply at levels three times higher the acceptable limit of 300 becquerel per kilogram. Nuclear experts believe airborne isotopes entered the water supply via the reservoirs and rivers from which the water is pumped.
The Health, Labor and Welfare Ministry instructed the village's residents to refrain from drinking the water, but said they could still use the water for bathing and washing.
The numerical standards for food and water are based on the premise of the radioactive material being ingested for a year.
Based on this, the experts then calculate how much of the radioactive substance would be absorbed into the body by both adults and children, and to what extent their health would be affected. The government's limits are based on the results of these calculations and set at a level that avoids health risks.
At the levels that have been detected so far, people can still safely ingest the food or water until safer alternatives are secured without facing health risks, according to the ministry.
===
Low doses may not cause cancer
Past radiation leaks have shown that people exposed to 3,000 millisieverts of radiation per hour have a nearly 50 percent chance of dying within 60 days if they do not receive medical treatment.
However, the only precise data illustrating the long-term effects of radiation are found in studies of A-bomb survivors from Hiroshima and Nagasaki.
It shows that exposure to 1,000 millisieverts of radiation per hour increases the chances of developing cancer by 150 percent. The lower the exposure, the lower the risk of cancer.
About 28,000 people who were exposed to levels of up to 100 millisieverts were monitored over a 40-year period. About 4,400 of them developed cancer. This figure, however, is less than 2 percent--81 people--higher than the average for people who have not been exposed.
There is almost no difference. Even nuclear experts are divided over the correlation between exposure to less than 100 millisieverts of radiation and higher risks of cancer.
Because of this, the risk line is set at 100 millisieverts.
In day-to-day life, people are exposed to about 2.4 millisieverts of naturally occurring radiation every year.
No upper limits are set on exposure to radiation for medical treatments, such as CT scans, because benefits outweigh the risks.
However, as long as there is uncertainty about the effects, people should avoid unnecessary exposure to radiation.
Government regulations require nuclear power plants to be built in a way that limits exposure of local residents to one millisievert per year.
The government is currently monitoring radiation levels across the country. From 4 p.m. to 5 p.m. Monday in Shinjuku Ward, Tokyo, the figure was 0.125 microsieverts, a level at which medical experts say there is no immediate effect on human health.
(Mar. 23, 2011)
There is a lot of erroneous information floating around about radiation contamination, making it important to brush up on the basics so you can know what is really happening.The government has placed restrictions on some products, including spinach from certain areas, after radioactive isotopes were detected on the produce and in the water supply after a series of accidents at the Fukushima No. 1 nuclear power plant.
It is important to remember that "radiation" refers to a wide variety of radioactive elements.
What effects do these elements have on the human body? How can one prevent exposure and minimize the health risks?
===
It's in the food--can I eat it?
On Monday, government inspectors found levels of radioactive iodine and cesium that exceeded legal limits in spinach, milk and other produce from Tohoku and Kanto.
The radioactive material was leaked from the power plant and scattered by the wind, which carried it to nearby farms, where it adhered to the surface of spinach and pastures where cows were grazing.
Ingesting radioactive isotopes leads to internal exposure to radiation.
The Nuclear Safety Commission has set standards for acceptable levels of radiation in water, milk and produce--excluding root vegetables, such as yams.
The decision to restrict shipments of these items was based on these numerical standards.
For dairy products such as milk, the NSC has determined 300 becquerel of radioactive iodine per kilogram and 200 becquerel of radioactive cesium per kilogram are safe for consumption.
For vegetables, acceptable levels increase to 2,000 becquerel and 500 becquerel, respectively.
Following the detection of high levels of radioactive substances in some agricultural products Monday, the government ordered Fukushima, Ibaraki, Tochigi and Gunma prefectures to halt shipments of spinach and kakina greens. It also ordered Fukushima Prefecture to halt milk shipments for the time being.
"Even if people eat these products, there will be no immediate effect," Chief Cabinet Secretary Yukio Edano said. "We have imposed the restrictions in case the radiation leak becomes protracted."
Food safety expert Hideaki Karaki, professor emeritus at the University of Tokyo, said: "As it stands, the radiation levels that have been detected in food present no danger. But in all likelihood, many consumers would refuse to buy the products even if they were shipped, so factoring in distribution costs, this restriction was unavoidable."
"Moving forward, similar incidents and harmful rumors need to be nipped in the bud by disclosing correct information, and farmers need to be properly compensated for their losses," he said.
In Iitatemura, Fukushima Prefecture, radioactive iodine was detected in the water supply at levels three times higher the acceptable limit of 300 becquerel per kilogram. Nuclear experts believe airborne isotopes entered the water supply via the reservoirs and rivers from which the water is pumped.
The Health, Labor and Welfare Ministry instructed the village's residents to refrain from drinking the water, but said they could still use the water for bathing and washing.
The numerical standards for food and water are based on the premise of the radioactive material being ingested for a year.
Based on this, the experts then calculate how much of the radioactive substance would be absorbed into the body by both adults and children, and to what extent their health would be affected. The government's limits are based on the results of these calculations and set at a level that avoids health risks.
At the levels that have been detected so far, people can still safely ingest the food or water until safer alternatives are secured without facing health risks, according to the ministry.
===
Low doses may not cause cancer
Past radiation leaks have shown that people exposed to 3,000 millisieverts of radiation per hour have a nearly 50 percent chance of dying within 60 days if they do not receive medical treatment.
However, the only precise data illustrating the long-term effects of radiation are found in studies of A-bomb survivors from Hiroshima and Nagasaki.
It shows that exposure to 1,000 millisieverts of radiation per hour increases the chances of developing cancer by 150 percent. The lower the exposure, the lower the risk of cancer.
About 28,000 people who were exposed to levels of up to 100 millisieverts were monitored over a 40-year period. About 4,400 of them developed cancer. This figure, however, is less than 2 percent--81 people--higher than the average for people who have not been exposed.
There is almost no difference. Even nuclear experts are divided over the correlation between exposure to less than 100 millisieverts of radiation and higher risks of cancer.
Because of this, the risk line is set at 100 millisieverts.
In day-to-day life, people are exposed to about 2.4 millisieverts of naturally occurring radiation every year.
No upper limits are set on exposure to radiation for medical treatments, such as CT scans, because benefits outweigh the risks.
However, as long as there is uncertainty about the effects, people should avoid unnecessary exposure to radiation.
Government regulations require nuclear power plants to be built in a way that limits exposure of local residents to one millisievert per year.
The government is currently monitoring radiation levels across the country. From 4 p.m. to 5 p.m. Monday in Shinjuku Ward, Tokyo, the figure was 0.125 microsieverts, a level at which medical experts say there is no immediate effect on human health.
(Mar. 23, 2011)
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