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Radioactive cesium was detected in the brown rice in the preliminary testing. Total 52 becquerels/kg of radioactive cesium was found, with 23 becquerels/kg of cesium-134 and 29 becquerels/kg of cesium-137. The amount was far below the national provisional safety limit (500 becquerels/kg total radioactive cesium).

Next to detect cesium in rice was Chiba.

From Mainichi Shinbun (8/26/2011):

Chiba Prefecture announced on August 25 that 47 becquerels/kg of radioactive cesium was found in the mochi-rice (glutinous rice) grown in Shirai City in Chiba Prefecture in the preliminary test before the harvest to survey the effect of radioactive materials from the Fukushima I Nuclear Power Plant accident. The amount of radioactive cesium was far below the national provisional safety limit (500 becquerels/kg). It is the second case of radioactive cesium detection in the country, the first one being in Hokota City in Ibaraki Prefecture.

According to the division for safe agriculture promotion in Chiba prefectural government, the brown rice taken at two locations within Shirai City on August 22 was tested. From one location, 47 becquerels/kg of radioactive cesium was detected, with cesium 134 22 becquerels/kg and cesium-137 25 becquerels/kg. The prefectural government plans to conduct the full survey on the brown rice after the harvest by the end of August, and if the rice tests under the provisional safety limit it will be allowed to be shipped.But in Fukushima, hardly any radioactive cesium was detected in the early harvest rice.

From Yomiuri Shinbun (8/26/2011):

Fukushima Prefecture announced on August 26 the test results of the early-harvest rice harvested in a location in Nihonmatsu City, two locations in Motomiya City, and one location in Koriyama City.

From the location in Nihonmatsu City, 22 becquerels/kg of radioactive cesium was found. No radioactive cesium was detected in all the other locations. Based on the results, the prefectural government has allowed the rice harvested in these locations, except for one in Motomiya City, to be shipped. It will be the first shipment of rice from Fukushima after the Fukushima I Nuclear Power Plant accident.

According to Fukushima Prefecture, two types of early-harvest rice harvested on August 25 and 26 were tested. When the rice in the Nihonmatsu City location was milled, no radioactive materials were detected. As to the location in Motomiya City (Arai-mura), the testing was done on all rice fields. If the results show the level of radioactive cesium is less than the provisional safety limit, the rice will be allowed to be shipped.

These cities are located in "Naka-dori" (middle third) of Fukushima Prefecture where highly radioactive rice hay has been found. 500,000 becquerels/kg of cesium was found in rice hay in Koriyama City, and in Motomiya City, 57 kilometers west of Fukushima I Nuke Plant, the number was even higher at 690,000 becquerels/kg. For your reference, Fukushima's radioactive cesium detection limit, according to the prefecture: 10 becquerels/kg

Radioactive cesium (cesium-137) in rice in Fukushima before the accident: ND to 0.14 becquerels/kg, after milling Radioactive cesium (cesium-137) in rice in Chiba before the accident: ND, after milling

Radioactive cesium (cesium-137) in rice in Ibaraki before the accident: ND to 0.045 becquerel/kg, after milling (source data for radioactive cesium in rice in Fukushima, Chiba, Ibaraki from Japan Chemical Analysis Center, from 2000 to 2009)

Part 4 / Osaka Bay, Whangarei / Nippon December 29 Cesium 134 783Bq/kg Cesium-137 39Bq/Kg Strontium-90 ND

8/19/2011: Cesium-134: 87,000 becquerels/cubic centimeters Cesium-137: 74,000 becquerels/cubic centimeter

Kyotoresident said... I wonder why the emphasis is only on iodine and cesium in media reports. Are they the most dangerous? Plenty of other stuff came out of Fukushima. Anyone know anything about this stuff? Xe-133, Sr-89, Sr-90, Ba-140, Te-127m, Te129m, Te-131m, Te-132, Ru-103, Ru-106, Zr-95, Ce-141, Ce-144, Np-239, Pu-238, Pu-239, Pu-240, Pu-241, Y-91, Pr-143, Nd-147, Cm-242, Sb-127, Sb-129, Mo-99All of this was let out in large quantities. Some more than cesium and iodine, some less.(data from Tepco)

arevamirpal::laprimavera said... They are the most abundant, the easiest to detect

It stands to reason that at some point the Ukrainian government would like to be able to use that land again, but the scientists have calculated that what they call cesium’s “ecological half-life” — the time for half the cesium to disappear from the local environment — is between 180 and 320 years.

“Normally you’d say that every 30 years, it’s half as bad as it was. But it’s not,” said Tim Jannik, nuclear scientist at Savannah River National Laboratory and a collaborator on the work. “It’s going to be longer before they repopulate the area.”

In 1986, after the Chernobyl accident, a series of test sites was established along paths that scientists expected the fallout to take. Soil samples were taken at different depths to gauge how the radioactive isotopes of strontium, cesium and plutonium migrated in the ground. They’ve been taking these measurements for more than 20 years, providing a unique experiment in the long-term environmental repercussions of a near worst-case nuclear accident.

In some ways, Chernobyl is easier to understand than DOE sites like Hanford, which have been contaminated by long-term processes. With Chernobyl, said Boris Faybishenko, a nuclear remediation expert at Lawrence Berkeley National Laboratory, we have a definite date at which the contamination began and a series of measurements carried out from that time to today. “I have been involved in Chernobyl studies for many years and this particular study could be of great importance to many [Department of Energy] researchers,” said Faybishenko.

The results of this study came as a surprise. Scientists expected the ecological half-lives of radioactive isotopes to be shorter than their physical half-life as natural dispersion helped reduce the amount of material in any given soil sample. For strontium, that idea has held up. But for cesium the the opposite appears to be true. The physical properties of cesium haven’t changed, so scientists think there must be an environmental explanation. It could be that new cesium is blowing over the soil sites from closer to the Chernobyl site. Or perhaps cesium is migrating up through the soil from deeper in the ground. Jannik hopes more research will uncover the truth.

“There are a lot of unknowns that are probably causing this phenomenon,” he said. Beyond the societal impacts of the study, the work also emphasizes the uncertainties associated with radioactive contamination. Thankfully, Chernobyl-scale accidents have been rare, but that also means there is a paucity of places to study how radioactive contamination really behaves in the wild.

“The data from Chernobyl can be used for validating models,” said Faybishenko. “This is the most value that we can gain from it.” Update 12/28: The second paragraph of this story was updated after discussion with Tim Jannik to more accurately reflect the idea of ecological half-life.

Citation: “Long-Term Dynamics of Radionuclides Vertical Migration in Soils of the Chernobyl Nuclear Power Plant Exclusion Zone” by Yu.A. Ivanov, V.A. Kashparov, S.E. Levchuk, Yu.V. Khomutinin, M.D. Bondarkov, A.M. Maximenko, E.B. Farfan, G.T. Jannik, and J.C. Marra. AGU 2009 poster session.

"Until early spring, produce was contaminated (on the surface with radioactive materials) that the No. 1 plant discharged into the atmosphere. But now, the major route of contamination is through plant roots," said Kunikazu Noguchi, a radiation protection expert at Nihon University. Whether absorption by plant roots can affect human health remains to be seen. Experts are warning that the region's soil and agricultural products will require close monitoring for many years.

At the moment, sampling data collected by the various prefectural governments indicate that no vegetables, except for those grown in Fukushima Prefecture, have been found to contain more than the government's provisional limit of 500 becquerels per kilogram since June. Likewise, as of Sept. 7, samples of pork, chicken, milk and fruit had also tested within the provisional radiation limit, apart from Fukushima products and tea from Chiba, Kanagawa, Gunma, Tochigi, Saitama and Ibaraki prefectures.

In fact, the amount of radioactive materials in most of the food sampled has been steadily declining over the past few months, except for produce from Fukushima. "The results of Fukushima's sampling tests show the amountof radioactive material contained in vegetables has dropped sharply in recent months, including those grown in areas with high radiation levels," Noguchi said. "People shouldn't worry about it much (for the time being)," he said. "But mushrooms and other vegetables grown in contaminated forests are likely tocontain high levels of radioactive materials."

his year, it's very important to conduct thorough surveys. The contamination will continue for a long time, so data collection is essential," Muramatsu said. "We need to be prepared for the following years by recording data this year and studying the rate at which cesium in the soil is absorbed by each kind of produce," Muramatsu said. In the meantime, the radioactivity itself will continue to weaken over the years. Cesium-134 has a half-life of 2 years and cesium-137 a half-life of 30 years, meaning the radiation they emit will drop by half in 2 years and 30 years.

"Data from the Chernobyl disaster show that radioactive cesium in soil tends to become fixed more strongly to clay minerals as time passes. So agricultural contamination will lessen next year," he said. Muramatsu urged that special caution should be taken over products grown in soil rich in organic matter, such as in forested areas. "If the soil is rich in organic matter, it makes (cesium) more easily transferable to plants. . . . Forest soil is rich in organic matter, so people should be careful," he said.

Now that soil in a wide area of eastern Japan has been contaminated with cesium, experts are calling for close monitoring of soil and produce. The education ministry conducted soil surveys in June and July at 2,200 locations within 100 km of the crippled plant. At 34 locations in six municipalities in Fukushima Prefecture, including Minamisoma, Namie and Iitate, the data said cesium levels had exceeded 1.48 million becquerels per sq. meter — the same level that was used to define the exclusion zone around Chernobyl in 1986. Yasuyuki Muramatsu, a radiochemistry professor at Gakushuin University, said that agricultural contamination will likely peak this year because cesium binds more strongly with minerals in soil as time passes, making it more difficult to be absorbed by plant roots.

The ratio of cesium-134 to cesium-137 in the Fukushima accident is estimated as 1-to-1, while the ratio during the 1986 Chernobyl disaster was 1-to-2. This indicates the radiation in Fukushima will weaken at a faster rate than at Chernobyl. Between April and early August, the farm ministry tested soil at some 580 locations in six prefectures, including Fukushima, Tochigi and Gunma, to get a better picture of the full extent of contamination.

According to the results, 40 locations in Fukushima Prefecture had an intensity exceeding 5,000 becquerels per kilogram — the government's maximum limit for growing rice. Many municipalities within 30 km of the Fukushima No. 1 plant were banned from planting rice based on similar tests conducted in April. In addition, the ministry has asked 17 prefectures in eastern Japan to conduct two-phase radiation tests on harvested rice.

So far, none of the tests performed on unmilled rice — including from Fukushima — exceeded the government's limit of 500 becquerels per kilogram. Masanori Nonaka, an agriculture professor at Niigata University who specializes in soil science, said rice grown in contaminated areas is likely to be tainted, but to what extent is anyone's guess. White rice, however, may prove to be safe, Nonaka said. Because most of the radioactive material will adhere to the bran — the part of the husk left behind after hulling — about 60 percent of the cesium can be removed just by polishing it, he explained. Other foods, such as marine produce, won't be as easy to handle, experts say. After the Chernobyl accident, for example, the radioactive contamination of fish peaked between 6 to 12 months after the disaster. The Fisheries Agency, meanwhile, has asked nine prefectures on the Pacific coast to increase their sampling rates to prevent contaminated fish from landing in supermarkets.

Prefectural governments began approving farmers to ship their harvest if test results showed samples from their produce did not show cesium exceeding the limit. Still, rice millers are concerned about buying new crops from areas near the plant as the current cesium standard, applied to brown rice, doesn’t ensure the safety of its by- products, including bran.

Rice Bran Cesium levels in rice bran, an ingredient used in Japanese compound feed for livestock, is about seven times as high as brown rice, said Ryo Kimura, the chairman of Japan Rice Millers and Distributors Cooperative. Because of this, feed makers are reluctant to buy bran made from brown rice that may contain more than 40 becquerels a kilogram of cesium, he said. Brown rice is polished to produce milled rice for sale to retailers and by-products are shipped to makers of cooking oil, pickles and animal feed.

Demand for this year’s rice crop has also been weakened as consumers hoarded last year’s crop amid radiation concerns, Kimura said. Domestic food-rice inventories, excluding the government’s reserve, fell 16 percent to a three-year low of 1.82 million metric tons in June as consumers boosted purchases after the disaster. The volume is equal to 22 percent of Japanese rice demand in the year ended June 30.

Lower Prices “Consumers who see the current cesium standard as lenient won’t buy rice from polluted areas,” said Nobuyuki Chino, president of Continental Rice Corp. in Tokyo. “Wholesalers are seeking rice that tested negative for cesium as they know grain containing radioactivity, even if the amount is smaller than the official standard, won’t sell well.” Stockpiles may increase by more than 100,000 tons by next June because of a weak demand and a good harvest this year, dragging down prices, said Chino.

Low demand for rice harvested in eastern Japan, affected by radiation fallout from the Fukushima plant, is reflected in a price gap between Tokyo and Osaka grain exchanges, Chino said. Rice for November delivery on the Tokyo Grain Exchange settled at 14,400 yen ($184) a bag on Oct. 12, 4 percent cheaper than the price on the Kansai Commodities Exchange in the western city of Osaka. The Kansai exchange trades rice produced in western Japan, while the Tokyo bourse handles rice grown in the east, including Fukushima prefecture.

Stricter Control The government has been slow to take measures to ease safety concerns as tighter regulation will boost costs for radiation testing, adding troubles to the nation struggling with swelling fiscal deficits, said Naoki Kazama, an upper-house lawmaker from the ruling Democratic Party of Japan. Stricter control may also increase a ban on shipments of local farm products and cause shortages, sending producers out of business and boosting compensation payments by Tokyo Electric Power Co., operator of the Fukushima nuclear plant.

“The government should put a priority on protecting human health, especially of our children,” Kazama said in an interview in Tokyo. “Now they are paying consideration to the interests of various parties evenly.” Kazama has proposed that all foods be tested for radioactive contamination and their radiation levels be labeled. The health ministry, which rejected the proposal as unfeasible, plans to revise cesium standards in food in line with recommendations from the Food Safety Commission.

Health Effects An expert panel on the commission compiled a report in July that said more than 100 millisieverts of cumulative effective doses of radiation over a lifetime could increase the risk of health effects in humans. The amount doesn’t include radiation from nature and medical exposure, it said.

The soil contamination as the result of the Fukushima I Nuclear Power Plant accident was reported on the August 29 meeting at the Ministry of Education and Science.

The survey found 34 locations in 6 municipalities exceeding the level of the confiscation/closed zone of the Chernobyl accident (1,480,000 becquerels/square meter of cesium-137 in soil). The purpose of the survey was to understand the radiation exposure of the residents. Prime Minister Kan said on August 27 that there might be locations where the residents wouldn't be able to return for a long time. The survey data validates the prime minister's comment.

According to the survey, the highest cesium-137 concentration in soil as of June 14 was in Okuma-machi in Fukushima Prefecture, within the no-entry evacuation zone, at 15,450,000 becquerels/square meter. If combined with cesium-134, the radioactive cesium concentration was 29,460,000 becquerels/square meter.

Total 16 location in 4 municipalities (Okuma-machi, Futaba-machi, Namie-machi, Tomioka-machi) exceeded 3,000,000 becquerels/square meter in cesium-137 concentration. The area with the high cesium-137 concentration extends northwest from the nuclear power plant. In total, 6 municipalities including Iitate-mura and Minami Soma City had the locations that exceeded the Chernobyl confiscation/closed zone level of cesium-137. The Ministry measured the soil samples from about 2,200 locations.Here's the map by Asahi Shinbun, including the locations with cesium-137 concentration of less than 1 million becquerels/square meter.

The Ministry did the survey twice in June and August. It selected the survey locations from the areas that showed relatively high level of cesium deposition in soil in the Ministry's aerial survey after the accident. 50 river locations and 51 wells were selected. Radioactive cesium and iodine-131 were measured in all 101 locations. Strontium and plutonium were measured in 10 river locations where the air radiation was high. Similarly, at 6 wells, only strontium was measured.

The highest cesium-137 (half life 30 years) for the river water was detected in Mano District in Minami Soma City (37 kilometers north by northwest from the nuke plant), at 2.0 becquerels/kg. The average amount of cesium-137 in river water was 0.58 becquerels/kg. The highest cesium-137 for the well water was detected in Nukazawa in Motomiya City (54 kilometers west of the plant), at 1.1 becquerels/kg. The average for well water was 0.49 becquerels/kg.

According to the Ministry of Education and Science, "Radioactive materials in both river water and well water are far below the provisional safety limit of 200 becquerels/kg". However, according to the Ministry's national survey in 2009, the highest level in river water was found in Akita Prefecture at 0.00037 becquerels/kg (ND in Fukushima). So, 2.0 becquerels/kg of cesium-137 detected this time in Fukushima is 5,400 times as much as the highest level in 2009 in river water. As to 1.1 becquerels/kg of cesium-137 from the well water, it is 6,500 times as much as the highest level detected in tap water in 2009.

The largest amount of strontium-90 (half life 30 years) was detected in a river in Onahama in Iwaki City, at 0.018 becquerels/kg, 5.14 times the level detected in the 2009 survey. Strontium-90 in well water was the same level as before the accident. Plutonium and iodine-131 were below the detection limit.

According to the Ministry's calculation on the internal radiation if one drinks the river water that had the maximum amount of radioactive materials for one year, cesium-137 would result in 0.025 millisievert, and strontium-90 in 0.00049 millisievert.Hmmm. They tested an alpha emitter (plutonium) and a beta emitter (strontium) in water in locations with high air radiation? What does high air radiation have to do with alpha and beta emitters? And what about other nuclides, like cobalt-60?The Ministry of Education tested water at these locations twice: first in late June to early July, then in early August. Looking at the result, there are two locations where the amount of radioactive cesium significantly INCREASED during the one month, indicating perhaps the inflow of radioactive materials from the surrounding mountains.The Ministry's document has very poor resolution, but here's the page that shows charts of cesium-137 detections (page 19 in the document):

It was not until October 6 that the Tokyo Metropolitan government conducted a more extensive testing of the green teas grown, picked, and processed in Tokyo in May, after it learned of the teas grown in neighboring Saitama and Chiba Prefectures found with radioactive cesium exceeding the provisional safety limit.If you look at the Tokyo government announcement, radioactive cesium was detected in significant amount in ALL but one teas tested. However, except for the three that exceeded the provisional safety limit, they can be sold without any restriction, and probably have been already sold. (The image of the announcement below is from savechild.net, with highlight on teas in which radioactive cesium was detected.)

Professor Tazaki collected the soil from the rice paddies in Nagadoro District of Iitate-mura, area with very high radiation, when she visited Fukushima Prefecture in late June. At her home in Kanazawa City, she planted the seedlings of "Koshihikari" which were germinated in Tawara-machi in Kanazawa City on the soil from Iitate-mura.

She harvested the rice in mid September, had it analyzed at a laboratory in Fukui Prefecture for cesium-137 in various parts of the rice and calculated the radiation levels per kilogram. The highest cesium-137 concentration of 2,600 becquerels/kg was found in (unprocessed) rice, 2,200 becquerels/kg from the straw, and 1,500 becquerels/kg from the roots. 50,000 becquerels/kg was detected from the soil itself.

To compare, "Koshihikari" rice planted in the rice paddies in Tawara-machi was also analyzed but no radioactive materials were detected at all.

Professor Tazaki says, "I myself was very shocked to find that the edible part of the rice had the most radiation. The decontamination of the soil should be carried out as soon as possible". She will teach farmers in Minami Soma City in Fukushima on a decontamination method using diatomite unique to Ishikawa Prefecture.Professor Tazaki found a bacterium that absorbs radioactive materials like uranium and thorium in Tanzania earlier this year, where she taught geology after she retired from Kanazawa University in 2009.Her result makes me very suspicious of the results announced by Fukushima Prefecture. Iitate-mura does have high soil contamination but it is by no means the highest. Judging by the rice hay contamination there are many other locations within Fukushima that may have radiation levels just as high and still grow rice because they lie outside the 30 kilometer radius from the plant. And yet the prefectural government says it's found 500 becquerels/kg of radioactive cesium at most from one location, and the rest is below 200 becquerels/kg.

It is also possible that the professor scraped the top soil only, whereas farmers in Fukushima tilled deeper and thus mixing the highly contaminated soil in the top 5 centimeters with the uncontaminated soil below, lowering the overall radiation.Well, despite the official ban with the threat of fines, the rice grew in Iitate-mura after all as at least one farmer spread the seed rice directly in the rice paddies. And as this Iitate-mura villager tweets, the rice has grown better than ever with far less work and resources. Why not test that too for radiation, instead of cutting it down?

The Yokohama Mayor is having her regular Wednesday press conference, but she has refused to let independent journalists including Yasumi Iwakami, who broke the news, attend the press conference. She only wants to deal with the "press club" members.For my recent posts on strontium-90 in Yokohama City, go here and here.

The mayor, who fed 80,000 elementary school children in the city with radioactive beef, then went to an APEC's women's meeting in San Francisco and appealed Yokohama. (As what?) And she wants her official residence renovated by city's taxpayers' money.

As for green tea, the tea producer was mixing the tea that passed the provisional safety limit but which still contained radioactive cesium with the tea made in Kyushu, far away from Fukushima I Nuke Plant. The blend was the radioactive tea 20%, the Kyushu tea 80%.Most water purification plants had voluntarily stopped shipping the radioactive sludge until the provisional safety limit was decided. However, the company who runs this particular water purification plant that continued to ship says, "The detection level was low. If the sludge was made into the garden soil it would be diluted further". The company blames the manufacturers who bought the radioactive sludge, saying "The ultimate responsibility rests with those who make [the sludge] into final products and sell them". The company is currently selling the radioactive sludge to the businesses that supply dirt for construction projects, as the national government has sent out an instruction that "the use of radioactive sludge in the garden soil had better be suspended".According to the green tea producer, there weren't enough of the tea leaves that passed the safety limit [but still contained radioactive cesium] to make it worthwhile to sell, so the company decided to mix it to make a "blend tea". The person in charge of the "blend tea" says "We made it clear in the package that it was a "blend tea", so there should be no problem. We just wanted to make the tea safer for the consumers".

SuspicionThese practices are not illegal, and when the contaminated products are mixed with non-contaminated products there should be less ill-effect on humans. However, if this "dilute and sell" model takes hold, it will only add to doubt and confusion for the consumers. Damage from "baseless rumors" may spread to milk and rice. It has been a standard practice to mix milk from different locations. The same goes for rice.The national consumer association federation chief proposes the detailed labeling of the place of manufacture on a prefectural level so that the consumers can choose safely.

However, there is no law requiring the place of manufacture for the garden soil, and there is no voluntary guideline by the industry either. The national standard for food labeling only requires the label "Made in Japan" in the case of "blended" produce like rice and tea and processed foods; there is no requirement to show the name of prefecture where the product is made. The Consumer Affairs Agency of Japan [which is supposed to regulate the industries with the welfare of consumers in mind] is not going to do anything at this point, saying "Places of manufacture for the blended goods may change, so it is not practical to require detailed labels".

On the other hand, the head of the Worldwide Agricultural Policy Information Center is critical. He says "The role of the national government is to stop the spread of radioactive materials. To allow goods with radioactive materials to be diluted and and sold widely would be considered as approval by the national government to spread the contamination [all over Japan]". JA agricultural co-op Fukushima is also distrustful of the government policy [or lack thereof], saying "There will be no "baseless rumors" if the produce that is found with radioactive materials is not sold".However, for now, we can only count on the voluntary effort by the industries. A new national policy would be necessary, just like when there was a problem of labeling "made in Japan" and "imported" goods.

The new policy was revealed during the meeting of experts affiliated with the Ministry of the Environment on August 27. So far, the Ministry's policy has been to allow the ashes with 8,000 becquerels/kg of radioactive cesium and below to be buried, but require the ashes that exceed that level to be stored temporarily while the Ministry decides on the disposal method.

Under the new policy, if radioactive cesium in the ashes exceeds 8,000 becquerels/kg but does not exceed 100,000 becquerels/kg, the ashes are allowed to be buried after they are bound with cement or put in a concrete container. If radioactive cesium exceeds 100,000 becquerels, then the ashes should be buried in the disposal facilities with a roof and/or with the concrete shield.

Radioactive cesium exceeding 8,000 becquerels/kg has been detected from the ashes from burning the regular household garbage in Kanto and Tohoku regions. The Ministry of the Environment has decided to apply the same rule as the disaster debris and allow the ashes to be buried. The municipalities will be able to bury the ashes that they have stored temporarily, but it may be difficult to obtain consent from the residents living near the disposal facilities.

The number "100,000 becquerels/kg" is significant in a sense, as the highest level of radioactive cesium found from ashes after burning the household garbage is 95,300 becquerels/kg in Fukushima Prefecture (link in Japanese). The number is high enough to clear the Fukushima garbage ashes, and it is probably high enough to clear garbage ashes from anywhere else.

Besides, as the NHK article states, even if it exceeds 100,000 becquerels/kg, all they need to do is to bury it in a disposal site with a roof or the concrete shield. This new policy is to be applied to ashes from disaster debris and regular garbage that are radioactive. It's not mentioned in the article but the ashes and slag from the radioactive sewage sludge will be likely to be disposed under the same policy - i.e. burn and bury. (And remember the "mix and match" scheme.)

In the meantime, some garbage incinerators and sludge incinerators at waste processing plants and sewage treatment plants in cities in Kanto have become so radioactive that they have to be shut down. (More later.) The entire country is to become the nuclear waste disposal site, because of one wrecked nuclear power plant. Talk about socializing the cost.

More radiation in spinach and other leafy vegetables can be removed if they are boiled. As for lettuces, throw away the outer leaf and rinse the rest well. Data from Chernobyl shows that rinsing lettuce can remove up to half of the cesium-134 and two thirds of the cesium-137. Cucumbers can be pickled with vinegar, which cuts radiation by up to 94 percent. Peeling carrots and boiling them with salted hot water would also help reduce cesium levels.

For fish and other seafood, however, watch out for strontium-90, which has a half-life of 29 years. According to Noguchi, far greater quantities of strontium-90 were released into the ocean than into the air and ground. Contrary to popular thinking, large fish are not necessarily riskier to consume. Though large fish do eat smaller fish, which leads some to believe they accumulate more radioactive materials, Noguchi says it is the small fish and flat fish that have stayed close to the Fukushima plant that pose more risk. Unlike large fish that swim longer distances, small fish cannot move far from contaminated areas. With tuna fish, rinse with water before eating or cooking. Boiling or marinating salmon helps remove cesium-137, and avoid eating fish bones, as they could contain strontium-90.

Fresh milk from Fukushima Prefecture was suspended from the market from mid-March until the end of April after it was found to contain radioactive iodine.

Cheese and butter are fine, too, because, during their production, the milk whey — the liquid that gets separated from curd — is removed. While rich in nutrition, cesium and strontium tend to remain in whey. Yogurt, which usually has whey floating on top, also undergoes radiation checks before going on the market, but if you are still worried, pour off the whey before you eat the yogurt.

Wakame (soft seaweed) and kombu (kelp) are integral parts of the Japanese diet. They flew off store shelves in the wake of the nuclear disaster, when consumers heard that the natural iodine in them might help them fight radiation contamination. Seaweed from the sea close to the nuclear plant, however, will likely absorb high levels of radiation in the coming years. You can rinse it before cooking, or choose seaweed harvested elsewhere.

The fallout densities were considerably lower in the Chugoku and Kyushu regions in western Japan. The smallest figure of 0.378 becquerel per square meter came from Uto, Kumamoto Prefecture. The density in Osaka was 18.9 becquerels per square meter. The peak value in Ibaraki Prefecture was 970,000 times larger than the cumulative fallout density of 0.042 becquerel per square meter in fiscal 2009, found in an earlier nationwide survey before the Fukushima crisis started.

Also on Nov. 25, the science ministry released maps of aerially measured radioactive cesium from the Fukushima plant that accumulated in Aomori, Ishikawa, Fukui and Aichi prefectures. This was the final batch of the 22 prefectures in eastern Japan where mapping was to be completed by the end of this year. Nowhere in the four prefectures did the accumulations exceed 10,000 becquerels per square meter, the threshold for defining an area as being affected by the nuclear accident. This reconfirmed the science ministry's view that radioactive plumes wafted only as far west as the border of Gunma and Nagano prefectures and as far north as the border of Miyagi and Iwate prefectures, ministry officials said.

Farm soil in Watari District in Fukushima was never officially tested for radioactive materials. An NPO (FoE Japan) tested soil samples from Watari with the help of Professor Yamauchi of Kobe University, but they are not from rice paddies or fields. The Fukushima prefectural government still doesn't test it. I am very curious to know the radiation levels in the farm soil in Watari and elsewhere where radioactive cesium has been detected in rice exceeding the provisional limit.