Latest news: Radioactive strontium found in 3 locations in Tokyo (Japan Today, Nov 25)

TOKYO — A citizens’ group has discovered radioactive strontium in soil in three locations in Tokyo, peaking at 51 becquerels per kilogram.

The group took measurements throughout Tokyo and Yokohama, and found radioactive mud in several locations, Sankei Shimbun reported Friday. In one case, a soil sample weighing one kilogram was found to be emitting 51 becquerels.

The group said they gathered soil through Oct 31 from various locations and then had them examined at an isotope research facility, Sankei said. The group claimed that a sample taken near the Ministry of Economy, Trade and Industry building in Kasumigaseki emitted 48 becquerels, one taken from outside the Tokyo International Forum in Yurakucho gave off 51 becquerels, and a third sample taken outside Kiyosumi-shirakawa Station in Koto Ward measured 44 becquerels per kilogram.

The group is the same one that discovered radioactive strontium 90 in sediment on the roof of a condominium in Yokohama in mid-October. In that case, the level of radioactive strontium was 195 becquerels, which is 95 becquerels per kilogram above the government standard.

It was the first time that radioactive strontium with a level higher than the government benchmark has been found so far from the stricken Fukushima Daiichi nuclear power plant.

Strontium 90 is a radioactive isotope of strontium, with a half-life of 28.8 years. Its presence in bones can cause bone cancer, cancer of nearby tissues and leukemia.

However, the Ministry of Education, Culture, Sports, Science and Technology said Thursday that the Yokohama strontium most likely did not come from the Fukushima Daiichi nuclear power plant. NHK quoted a ministry spokesperson as saying the isotope research did not detect strontium 89 with a half-life period of around 50 days, which would have been the case if it was linked to Fukushima. The ministry said the test detected 0.82 to 1.1 becquerels per kilogram of strontium 90 with a half-life of around 29 years, NHK reported.

Radioactive strontium in Yokohama apparently unrelated to Fukushima (Mainichi) November 25, 2011

TOKYO (Kyodo) — The science ministry said Thursday that radioactive strontium detected in sediment in Yokohama appears to be unconnected to the nuclear crisis at the Fukushima Daiichi power plant triggered by the March 11 earthquake and tsunami.

The ministry tested sediment collected at two locations in Yokohama’s Kohoku Ward by the city office and soil in the neighborhood but did not detect strontium 89 with a half-life period of around 50 days, which would have been detected if the incident was related to the Fukushima nuclear crisis.

The test detected 0.82 to 1.1 becquerels per kilogram of strontium 90 with a half-life of around 29 years, within levels observed prior to the nuclear crisis.

The Ministry of Education, Culture, Sports, Science and Technology suspects the presence of the substance is attributable to past nuclear experiments conducted in the atmosphere.

In a test conducted by the Isotope Research Institute in Yokohama at the request of the city office, the private institute measured both strontium 89 and strontium 90, and detected 59 to 129 becquerels per kg of strontium.

Regarding the significant difference in figures detected by the ministry and the institute, the ministry said the institute’s test may have also detected radium and other radioactive substances not related to a nuclear plant accident.

Meanwhile, radioactive strontium has been detected in soil samples taken from three locations in downtown Tokyo, a citizens’ group said Thursday.

Soil collected from outside the Ministry of Economy, Trade and Industry, and the Tokyo International Forum, both in Chiyoda Ward, and the Kiyosumi-Shirakawa subway station in Koto Ward measured 48, 51 and 44 becquerels per kg, respectively, the group said, against 10 to 20 becquerels per kg seen prior to the Fukushima nuclear crisis at various places in Japan.

The same group discovered in October up to 195 becquerels of radioactive strontium in sediment from the top of an apartment building in Yokohama, south of Tokyo.

If inhaled or ingested, strontium tends to accumulate in bones just like calcium. It is believed to cause bone cancer and leukemia.

TOKYO —The Ministry of Health, Labor and Welfare said Thursday that it will review its radioactivity safety limits on food and drink, classifying infant food such as formula in a new group.

The ministry currently sets radiation limits for five categories—drinking water, milk and dairy products, vegetables and grain, and other food items including meat, eggs and fish, NHK reported. The limit for radioactive cesium is 200 becquerels per kilogram for water, milk and dairy products, and 500 becquerels for the three other categories.

Under the new recommendations, there will now be four categories—water, milk, other food items and baby food, which will have its own category, NHK reported.

The ministry plans to reduce the cesium limits to around 1 millisievert per year from the current level of 5 millisieverts, NHK reported.

TEPCO: Radioactive substances belong to landowners, not us (Asahi, Nov 25)

During court proceedings concerning a radioactive golf course, Tokyo Electric Power Co. stunned lawyers by saying the utility was not responsible for decontamination because it no longer “owned” the radioactive substances.

TOKYO —

Orchards and farms throughout Fukushima Prefecture surrounding the stricken Daiichi nuclear power plant are currently undergoing what is being described as a “decontamination experiment.”

Radiation experts say that radioactive material sticking to the bark of trees and the skin of fruit is easily absorbed into the crop. The Japanese Central Union of Agricultural Cooperatives (JA) believes that by spraying the trees with high-powered hoses and stripping their bark, they can halve the amount of contaminant present.

Fuji TV reported that tests are currently being conducted at around 3,000 locations in Fukushima in an attempt to further improve the success rate. JA Union President Yuji Azuma said he hopes they will approach zero contamination and be ready to sell their produce from next year.

N-watchdog gets health role / New agency to handle residents’ well-being, not just reactors (Yomiuri, Nov. 25, 2011)A new nuclear safety agency to be established in April will deal with health problems caused by radioactive materials released from the Fukushima No. 1 nuclear power plant, it has been learned.The new watchdog was expected to focus on regulating nuclear reactors and responding to nuclear emergencies. However, the government apparently plans to strengthen the agency’s responsibilities by expanding its portfolio.The new agency–which will be an extraministrial bureau of the Environment Ministry–plans to tap the ministry’s expertise in handling the Minamata mercury poisoning disease and other environmental disputes, government sources said.The agency will collect data and conduct long-term research because it remains unknown what health risks radioactive materials leaked by the nuclear plant have caused or will cause to local residents. The entity also will handle any lawsuits filed against the government, the sources said.The agency will take over functions of existing nuclear regulatory organizations, including the Nuclear and Industrial Safety Agency, which is under the Economy, Trade and Industry Ministry. Since the March 11 earthquake and tsunami triggered meltdowns at the Fukushima plant that required thousands of residents to be evacuated, many observers have criticized the fact that the industry ministry is in charge of both promoting and regulating nuclear power.The Cabinet Office’s Nuclear Safety Commission will be consolidated into the new agency, and the Education, Culture, Sports, Science and Technology Ministry will transfer the role of monitoring radioactive materials to the new body.

The new agency, which will have about 500 employees, is expected to be responsible for:

— Monitoring residents’ radiation exposure levels over an extended period.

— Epidemiological studies that will be used to create a database.

— Research on the effect of radiation on humans.

— Establishing environmental standards for radiation protection.

The Fukushima prefectural government has started lifetime thyroid examinations on about 360,000 prefectural residents who were 18 or younger at the time of the accident at the nuclear plant. The new entity will advise and assist such programs, the sources said.

Officials who hold doctor’s licenses will be placed in the agency’s departments in charge of health damage issues. The government also has begun setting up an advisory research panel, the sources said.

A special government task force has been dealing with issues related to residents’ health problems stemming from the nuclear disaster. However, the task force, which arranged for internal radiation exposure checkups, will be dissolved when the nuclear crisis is brought under control. The panel is chaired by Prime Minister Yoshihiko Noda.

The Environment Ministry has jurisdiction over government compensation for Minamata patients. Last year it compiled relief measures to help unrecognized patients with the disease, which helped the government reach out-of-court settlements with major groups of plaintiffs this year.

The envisaged nuclear safety agency is expected to use the ministry’s expertise in handling the Minamata case, according to the sources.

No specific health damage arising from radiation leaks at the Fukushima nuclear plant has been confirmed. It remains unknown whether there will be such cases and, if there are, how serious they will be. Concrete steps will be taken only after actual health problems have come to light, and if such damage could be recognized as a pollution-caused disease like Minamata disease, the sources said.

Nuke accident-linked cancer may be impossible to detect

Experts remain divided over health risks from small doses of radiation

(Japan Times, Nov 25)

FUKUSHIMA — Even if the world’s worst nuclear accident in 25 years results in many people developing cancer, we may never find out.

Looking back on the early days of the Fukushima nuclear disaster, that may sound implausible.

But the ordinary rate of cancer is so high, and our understanding of the effects of radiation exposure so limited, that any increase in cases following the triple meltdowns at the Fukushima No. 1 nuclear plant may go undetected.

Several experts inside and outside Japan said that cancers caused by the massive amounts of radiation the plant emitted may be too few to show up in large population studies, such as the long-term survey of the 2 million residents in Fukushima Prefecture just getting under way.

That could mean thousands of cancers will slip under the radar in a study covering millions of people. Some of the dozen experts interviewed said they believe the radiation doses most people in Japan have been exposed to fall in the “low-dose” range, where the link to cancer remains unclear.

The cancer risk may be absent, or just too small to detect, said Fred Mettler, a radiologist who led an international study into health effects following the 1986 Chernobyl disaster.

That’s partly because cancer is one of the top killers in industrialized nations, in which the average lifetime cancer risk is about 40 percent. The odds are high that if people in such countries live long enough, they will die of cancer.

In any case, the radiation doses of the Fukushima Prefecture residents targeted in the new, 30-year survey were probably too small to have a noticeable effect on cancer rates, said Seiji Yasumura of Fukushima Medical University. Yasumura is helping run the project.

“I think he’s right,” as long as authorities limit children’s future exposure to radiation, said Richard Wakeford, a visiting epidemiology professor at the University of Manchester’s Dalton Nuclear Institute in England. Wakeford, who’s also editor of the Journal of Radiological Protection. He said he’s assuming that the encouraging data he’s seen on the risk for thyroid cancer are correct.

But the idea that cancers linked to the Fukushima crisis may go undetected gives no comfort to Edwin Lyman, a physicist and senior scientist with the U.S.-based Union of Concerned Scientists, a leading nonprofit group that advocates for nuclear safety. He said that even if cases of cancer don’t show up in population studies, that “doesn’t mean the cancers aren’t there, and it doesn’t mean it doesn’t matter.”

“I think that a prediction of thousands of cancer deaths as a result of the radiation from the Fukushima accident is not out of line,” Lyman said. But he stressed that authorities can do a lot to limit the toll by reducing future exposure to the radiation released into the environment by the plant’s wrecked reactors. That could mean conducting expensive decontamination projects, designating large areas of land as permanently off-limits and preventing people from ever returning home, he said. “There’s some difficult choices ahead.”

The Cabinet this month endorsed a plan to cut contamination levels in half within the next two years. The government also recently announced it plans to study the risk from long-term exposure to the low dose radiation limit it imposed following the nuclear accident. The limit was used as a gauge for evacuating residents in the prefecture.

The Fukushima No. 1 plant was crippled by the 15-meter tsunami generated by the 9.0-magnitude earthquake that struck off the coast of Tohoku on March 11. In some areas the waves swept up to 10 km inland. Authorities estimate the plant’s reactors leaked about one-sixth of the radiation released during the Chernobyl accident, and spewed iodine-131, cesium-137 and 29 other radioactive materials that contaminated the water, soil, forests and crops in a large area around the facility. A recent study suggested that emissions of cesium-137 were in fact double the amount estimated by the government.

So far, no radiation-linked deaths or sickness have been reported among either local residents or the workers trying to bring the plant under control.

A preliminary survey over the summer of 3,373 evacuees from the 10 towns closest to the stricken plant showed their estimated internal exposure doses over the next several decades would be far below the levels officials deem harmful.

But while the Fukushima disaster has stopped making headlines around the world, many Japanese remain concerned about the long-term health effects. And many don’t trust the reassurances by government scientists such as Fukushima Medical University’s Yasumura.

Many consumers worry about the safety of farm produce from Fukushima and surrounding prefectures, although food and fish products found to exceed government-set radiation limits have been barred from the market. For example, mushrooms harvested in and around Fukushima are frequently found to be contaminated and stopped from reaching the market. But the government’s choice of a maximum level for internal radiation exposure from food has also caused controversy.

Fukushima Prefecture, meanwhile, has distributed radiation monitors to 280,000 children at its elementary and junior high schools. Many kids are allowed to play outside for only two or three hours a day. Schools have removed topsoil from their grounds to reduce their students’ exposure to contamination, and the education ministry has provided radiation handbooks for teachers. Thousands of children have been moved out of the prefecture since the March disasters triggered the nuclear crisis, mainly due to radiation fears.

Many parents and concerned citizens in and around Fukushima, as well as some as far as Tokyo, carry Geiger counters to measure radiation levels in their neighborhoods each day, especially near schools and kindergartens. The devices are probably one of the most popular electronics gadgets in the country since the start of the disaster. People can rent them at DVD shops or drug stores in Fukushima Prefecture, and many Internet rental businesses specializing in Geiger counters also have emerged.

Citizens’ groups are also setting up radiation measuring centers where people can submit vegetables, milk or other foods for testing. Some people are turning to the traditional Japanese diet — pickled plum, miso soup and brown rice — based on the belief that it boosts the immune system.

“I try what I believe is the best, because I don’t trust the government any more,” said Chieko Shiina, a Fukushima Prefecture resident who switched to such a diet. The 65-year-old farmer had to close a small “ryokan” inn because of the nuclear crisis.

She thinks leaving Fukushima would be safer but says she has nowhere else to go.

“I know we continue to be exposed to contamination, even right at this moment. I know it would be best just to leave Fukushima,” she said.

Yuka Saito, a mother of four who lives in a neighborhood near the reactors where the government recently lifted its evacuation order, said she and her three youngest children spent the summer in Hokkaido to get away from the radiation. She tells her children, aged 6 to 15, to wear medical masks, long-sleeved shirts and a hat whenever they go out, and not to play outside.

She still avoids drinking tap water and monitors radiation levels daily around her house and the kindergarten and schools her children attend. She keeps a daily log of the readings.

“We in Fukushima are exposed to radiation more than anyone else outside the prefecture, but we just have to do our best to cope,” she said. “We cannot stay inside our homes forever.”

Officials say that mental health problems caused by excessive fear of radiation are prevalent among Fukushima residents and are more of a problem than the actual risk of developing cancer from the radiation.

But what kind of cancer risks do people really face?

Information on actual radiation exposure for individuals is scarce, and some experts say they can’t draw any conclusions yet about the risk to the general population.

But Michiaki Kai, professor of environmental health at Oita University of Nursing and Health Sciences, said that based on tests he has seen on people and their exposure levels, nobody in Fukushima Prefecture — except for some workers at the nuclear plant — has been exposed to harmful levels of radiation.

Radiation generally raises the risk of cancer in proportion to the exposure. Many experts and regulators still believe this holds true for low dosages. But other experts say direct evidence to prove this theory is lacking, and that it remains unclear whether such small levels raise the cancer risk.

“Nobody knows the answer to that question,” said Mettler, who led the Chernobyl study, and is also a professor emeritus of radiology at the University of New Mexico and the U.S. representative to the U.N. Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). If such low doses do produce cancers, they’d be too few to be detected against the backdrop of normal cancer rates, he said.

To an individual the question may have little meaning, since it deals with the difference between no risk and small risk. For example, the general population was told to evacuate from areas where they would be exposed to more than 20 millisieverts of radiation a year. A dosage of 20 millisieverts is about seven times the average dose of background radiation Americans are exposed to in a year. A child exposed to 20 millisieverts for a year would face a calculated risk of about 1 in 400 of getting cancer someday as a result, said David Brenner of Columbia University. So that would only increase the typical lifetime cancer risk of about 40 percent by 0.25 percent, he said.

The average radiation dose among the 14,385 workers who worked at the nuclear plant through July was 8 millisieverts, according to the central government. The average lifetime risk of cancer to an individual from such a dose alone would be calculated at about 0.05 percent, or 1 in 2,000, Brenner said.

But he also stressed that such calculations are uncertain because scientists know so little about the effects of such small doses of radiation.

In assessing the Fukushima disaster’s effect on the population, low radiation doses pose another question: If many people are each exposed to a low dose, can you multiply their individual calculated risks to forecast the number of cancer cases in the population?

Brenner thinks this is possible, which is why he believes some instances of cancer related to the Fukushima crisis might even appear in Tokyo, although each resident’s risk is “pretty minuscule.”

But Wolfgang Weiss, who chairs the UNSCEAR radiation committee, said the U.N. body considers it inappropriate to predict a certain number of cancer cases due to low doses of radiation because the risks of low levels of exposure remain unproven.

Nuclear accidents can cause cancer of the thyroid gland, but the disease is highly treatable and rarely fatal. The thyroid absorbs radioactive iodine.

After the Chernobyl disaster, some 6,000 children exposed to radioactive fallout subsequently developed thyroid cancer. Experts blame contaminated milk.

But the thyroid threat was apparently reduced in Japan as authorities closely monitored the radiation levels of dairy products and Japanese children do not traditionally consume a lot of milk, although their dairy intake has been rising in recent years.

Still, the new Fukushima survey will check the thyroids of about 360,000 people under age 18, with followups planned every five years throughout their lifetimes. It will also track women who were pregnant in the early stages of the crisis, conduct checkups focused on mental health and lifestyle-related illnesses for evacuees and others living near the no-go zone around the plant, and ask residents to fill out a 12-page questionnaire to assess their radiation exposure during the first weeks of the reactor meltdowns.

But the survey organizers are having trouble getting responses, partly because many locals are living at new addresses. As of mid-October, fewer than half the residents had responded to the health questionnaire.

Some residents are also skeptical about the survey’s objectivity because of their general mistrust of the government, which repeatedly delayed disclosing key data and revised evacuation zones and safety standards after the accident. In addition, the government’s nuclear safety commission recommended the use of iodine tablets, but none of the residents received them either before or during the evacuations, when the medicine would have been most effective at protecting thyroid glands.

Some even wonder whether the study is using them as human guinea pigs to examine the impact of radiation on humans.

Eisuke Matsui, a lung cancer specialist and a former associate professor at Gifu University School of Medicine, criticized the project, saying it appears to largely ignore potential radiation-related health risks such as diabetes, cataracts and heart problems that some studies of the Chernobyl crisis have hinted at.

“If thyroid cancer is virtually the only abnormality on which they are focusing, I must say there is a big question mark over the reliability of this survey,” he said.

He also suggested sampling hair, clipped nails and shed baby teeth to test for radioactive isotopes such as strontium that are undetectable under the survey’s current approach.

“We should check as many potential problems as possible,” Matsui said.

Fukushima Medical University’s Yasumura acknowledges the main purpose of the study is “to relieve radiation fears.”

Matsui, however, said that “a health survey should be a start, not a goal.”

Tatsuhiko Kodama, head of the Radioisotope Center at the University of Tokyo, urged quick action to determine cancer risks.

He said large population surveys and analyses will take so long that it would make more sense to run a careful simulation of radiation exposure and do everything possible to reduce the risks.

“Our responsibility is to tell the people now what the possible risks to their health could be,” he said.

Over 80 percent of nuke reactors to be shut down (NHK, Nov 25)

Earlier news:

Greenpeace seafood analysis finds more Fukushima radioactive contamination (Greenpeace, Nov 22)

As our team in Japan continues to monitor the radioactive contamination of land and sea that resulted from the destruction of the Fukushima Daiichi reactors, we’re still finding very disturbing evidence.

The results of another round of analysis of seafood caught in Japanese waters are in (you can read about the last round of results here), and show us once again that the Japanese government and retailers are still not doing enough to protect people from the contamination.

Between October 12 and November 8 our team, led by Greenpeace Japan Oceans Campaigner Wakao Hanaoka, took seafood samples from the same five supermarket chains – Aeon, Ito Yokado, Uny (Apita), Daiei and Seiyu – [DW1] as featured in the first round of research, taking 15 samples from each. Of the 75 samples, radioactive cesium 134 and 137 were detected in 27. There was no company whose products were not contaminated.

The samples that stood out were from Pacific cod. In total, seven cod caught in Hokkaido, Iwate and Miyagi, were sampled and five were found to be contaminated. A sample from a cod caught in Hokkaido and sold at the Uny Totsuka Shop in Kanagawa prefecture, showed a contamination of 47.3 Becquerel per kg. Japanese researchers have just announced they believe 80% of the radiation from Fukushima fell into the Pacific ocean. Like elsewhere in the world, cod is a very popular fish among Japanese people.

The Pacific cod wasn’t the only contaminated fish we found. Cesium 134 and 137 were detected in all five samples of Bigeye tuna we took and in all five samples of Skipjack tuna.

Wakao and the team also analysed one sample of canned mackerel. Although the level of contamination was not very high (4.6 Becquerel per kg), there is no detailed information about the fish’s origin such as where it was caught and what type of mackerel it is. The label on the can simply says “made in Japan”. The government’s labelling regulation for canned fish and processed fish products is far less stringent than for fresh fish products and needs to be addressed immediately.

This evidence shows contamination below the Japanese limits government’s official limit of 500 Becquerel per kg but it still poses a health risk, particularly for children and pregnant women. It’s clear that radioactive contamination has entered Japan’s food chain and is being spread by the country’s food distribution system.

We’re now eight months into the Fukushima crisis and yet, with many examples of radioactive contamination in food being found, the government is still showing no sign of establishing an official, national food screening and labelling system that would give shoppers much needed information and help protect their health. How long do the Japanese people have to wait?

To reduce this spread of contamination Greenpeace is continuing to pressure the major supermarkets and retailers in Japan. The country’s largest retailer AEON has already pledged that it will sell only radiation-free food from now on. On November 24 Greenpeace will be publishing its Retailer Ranking showing the contaminated of fish sold by other supermarket companies. Will they follow AEON’s laudable example? Watch this space.

Architect of Reactor 3 warns of massive hydrovolcanic explosion (Fukushima Diary, Nov 19)

U.N. group wants to learn from 3/11 response (Japan Times, Nov 20)