Cesium in Baby Milk Powder Shows Nuclear Risk for Japan’s Food (Business Week, December 06, 2011)
Dec. 7 (Bloomberg) — Radioactive cesium was found in milk powder made by a Meiji Holdings Co. unit, causing the shares to fall the most in eight months and raising concern that nuclear radiation is contaminating baby food.
Meiji this week found traces of cesium-137 and cesium-134 in batches of “Meiji Step” made in March, the Tokyo-based company said yesterday. Levels in the 850-gram (30-ounce) cans are within safety limits and don’t pose a health risk, it said. The investigation was triggered by a customer complaint last month, a spokesman said.
The finding highlights the radiation threat to food in Japan nine months after the Fukushima nuclear plant was wrecked by an earthquake and tsunami. Prolonged exposure to radiation in the air, ground and food can damage DNA, causing leukemia and other cancers. While infants are especially susceptible, the milk powder may not be a significant threat if contamination is limited to small quantities in isolated batches, said Slim Dinsdale, a food safety consultant based in Norwich, England.
“If it’s just a one-off, ‘safe’ dose then it may well be of a similar level to the background levels” residents are routinely exposed to, Dinsdale said in a telephone interview. “I’d want to avoid cesium if I knew it was there, whether it was a safe dose or not.”
Tests conducted on Dec. 3 and 4 found Cesium-134 at levels as high as 15.2 becquerels per kilogram, while cesium-137 reached 16.5 Bq/kg, according to Meiji. A becquerel is a measure of radioactivity. The permissible level for milk and dairy products for infants is 200 Bq/kg, the company said.
As a result of the tests, the company said it’s recalling 400,000 cans of “Meiji Step,” a powdered milk formulated for babies older than nine months, packaged in April and mostly distributed in May. The affected cans expire in October 2012.
“The dose is pretty small,” said Richard Wakeford, a visiting professor in epidemiology at the University of Manchester’s Dalton Nuclear Institute. It wouldn’t be necessary to ban the products from a radiological protection point of view, he said. “But you can understand the kind of pressure that the manufacturer would be under in these circumstances.”
Meiji shares fell as much as 13 percent in Tokyo yesterday, ending trading down 9.7 percent at a 30-month low of 3,020 yen. Rival Morinaga Milk Industry Co. dropped 3.5 percent to a three- year low of 275 yen and Megmilk Snow Brand Co. shed 3.6 percent.
The products were made at a factory in Saitama prefecture, north of Tokyo, between March 14 and March 20, the company said. The raw milk had been produced before the March 11 disaster and water used in the production process wasn’t found to be contaminated, Meiji said.
The monitoring didn’t detect radioactive materials in Meiji’s “Hohoemi” brand, the company said. Retailers Seven & I Holdings Co. and Aeon Co. said they are offering to replace the recalled products.
The presence of cesium at the levels found indicates contamination from nuclear fission products, possibly as a result of explosions at Tokyo Electric Power Co.’s Fukushima plant, said Stephen Lincoln, a professor of chemistry at the University of Adelaide in South Australia.
“There is only one source of cesium in that milk: nuclear fission from a nuclear reactor or spent fuel,” Lincoln said in an interview yesterday. “There may be parts around Fukushima that will have to be evacuated for 100 years. There is no way you can make radioactive decay happen more swiftly.” … Read the rest of the article here.
Cesium in Baby Milk Powder Shows Nuclear Risk for Japan’s Food (NHK, December 06, 2011)
Major Japanese food company Meiji says it will replace about 400,000 cans of powdered milk for free, after samples of the product were found to contain radioactive cesium.
Meiji says 30.8 becquerels of radioactive cesium per kilogram was found in powdered milk produced from March 14th to the 20th. The level is below the government safety limit of 200 becquerels per kilogram, but Meiji decided to replace all of the powdered milk it produced during the period.
The product was tested after consumers questioned its safety last month.
Meiji says all of its powdered skim milk used as a base for other powdered milk products was made before the March 11th disaster.
Some of it was made in Hokkaido in northern Japan, but a large part was imported from Australia and other areas of Oceania, and processed at a plant in Saitama Prefecture, near Tokyo, after March 11th.
Meiji says it has yet to determine the cause of the contamination, but that it may have resulted from exposure to radioactive cesium from the Fukushima Daiichi plant when the processing facility was ventilated to dry the product.
TOKYO (Kyodo) — Radioactive cesium of up to 30.8 becquerels per kilogram has been found in baby formula manufactured and sold by Meiji Co., the major food company said Tuesday, citing an internal inspection.
The company suspects a link with the radioactive leaks from the Fukushima Daiichi nuclear power plant damaged by the March earthquake and tsunami, saying that raw milk for its “Meiji Step” powders may have come into contact with airborne radioactive cesium when it was being dried.
Radioactive cesium has been found in baby formula for the first time since the disaster, according to the Health, Labor and Welfare Ministry, which has begun looking into the matter.
The level of cesium-134 and cesium-137 contained in the product remains below the government-set allowable limit of 200 becquerels per kilogram. Meiji said in a statement that the level “is said to be one that does not influence health even if (the formula) is drunk every day.”
The company nonetheless plans to offer customers free replacements, a move that affects about 400,000 850-gram cans of the Meiji Step formula, a company official said.
Amid concern that babies are more susceptible to the harmful effects of radioactive materials than adults, the ministry has planned to set a new limit for food products for babies.
Replacements will be offered for batches whose recommended consumption deadlines are Oct. 3, 4, 5, 6, 21, 22, 23 and 24 next year, according to the manufacturer. The deadline is printed on the bottom of each can.
The formula in question was manufactured at a company plant in Kasukabe, Saitama Prefecture. It came from cow milk produced before the March 11 disaster, according to the company.
“Because the cesium gets diluted to 3 to 4 becquerels (per kg) when the powders are put into hot water, we don’t think it will have an impact on health. But we still want to address the anxieties of those who bought the product with replacements,” the official said.
Prior to the latest discovery, the company had said no radioactive cesium was found in its product samples. The cesium found in the latest case was detected in stocks not subject to sampling tests.
Meiji commands roughly a 40 percent share of the domestic baby formula market.
Strict radioactivity standards set for school lunches (Asahi, Dec 2)
The education ministry on Nov. 30 set its first radiation safety standards for lunches provided at elementary and junior high schools, which will apply to 17 prefectures in eastern Japan.
The standard is 40 becquerels or less per kilogram for radioactive substances contained in the lunches, and will essentially be used as a regulation threshold.
In its notification, the Ministry of Education, Culture, Sports, Science and Technology also instructed the prefectures to buy radiation detectors with a minimum detection limit of 40 becquerels or less per kilogram, and to publicize the results of their inspections. Purchases of five detectors per prefecture will be eligible for central government subsidies.
The ministry is also envisaging item-by-item inspections of food ingredients in the lunches before they are cooked.
The tolerable level for school lunches is much stricter than the provisional standards of 200 becquerels per kilogram for drinking water, milk and dairy products, and 500 becquerels per kilogram for vegetables, meat, fish and grains.
“We adopted one-fifth the figure of the stricter standard (of 200 becquerels) to be on the safe side,” an education ministry official said.
The Ministry of Health, Labor and Welfare is considering reducing the maximum tolerable levels of internal radiation from cesium in food from the current 5 millisieverts per year to 1 millisievert per year.
The education ministry decided on its level for school lunches in light of the expected revision of the health ministry’s standards.
The ministry’s notification was sent to all six prefectures in the Tohoku region, all 10 prefectures in the Kanto Koshinetsu region, and Shizuoka Prefecture.
The ministry will let prefectural and municipal governments decide which ingredients should be inspected and what measures should be taken in response to specific levels of radioactive content.
The education ministry, however, provided instructions on how schools should respond when radioactivity exceeds 40 becquerels per kilogram in the lunches.
If only one ingredient is found above that level, the school lunches should be provided after that item is removed, according to the ministry.
But if the level exceeds the standard in more than one ingredient, making it difficult to complete the lunches with the remaining ingredients, only bread and milk should be provided to the children, the ministry said.
Researcher: Pollen mask prevents cesium inhalation (Asahi, December 02, 2011)
A type of mask sold in drugstores for hay-fever sufferers may also prove effective in preventing internal exposure to radioactive cesium, a researcher at the University of Tokyo said.
Shogo Higaki, who specializes in radiochemistry at the university’s Radioisotope Center, said on Nov. 30 that he compared levels of cesium that became attached to airborne pollen and dust with levels of cesium on the surface of a three-dimensional, non-woven pollen mask he wore from 3 p.m. on March 15 to 9 a.m. on March 16.
The results show that the mask almost completely eliminated the amount of cesium inhaled and cut the amount of radioactive iodine ingested by one-third.
Without the mask, the level of internal exposure to radioactive materials, such as iodine, could have totaled 9.3 microsieverts during those hours, he said.
His research was conducted at the university’s Hongo campus in Tokyo’s Bunkyo Ward after hydrogen explosions rocked the crippled Fukushima No. 1 nuclear power plant.
The results were presented at a convention of the Japanese Society of Radiation Safety Management in Yokohama on Nov. 30.
TEPCO: Radioactive strontium leaked into the sea (NHK, Dec 6)
The operator of the Fukushima Daiichi nuclear power plant says about 150 liters of radioactive contaminated water, containing radioactive strontium, has leaked into the sea.
The Tokyo Electric Power Company found on Sunday that massive amounts of radioactive water had leaked from a desalination device. It said that up to 300 liters of radioactive water leaked out from cracks in the foundation of the building which contains the device.
The company detected beta-ray emitting radioactive substances, including strontium, from a gutter near the building. The gutter drains into the Pacific Ocean.
TEPCO announced on Tuesday that it estimates about 150 liters of radioactive water reached the sea.
Radioactive strontium accumulates in the bones once inside a body due to its similar properties to calcium and releases radiation for a long time. One type of strontium — strontium 90 — has a half-life of 29 years.
TEPCO apologized for the leak. However the power company said that, judging from the amount released, it is likely to have almost no effect on the environment.
TEPCO: 45 tons of radioactive water leaked at plant(Asahi, Dec 06) | TEPCO reveals new contaminated water leak at Fukushima plant (Japan Today, Dec 6)
TOKYO — Tokyo Electric Power Co (TEPCO) said Sunday that at least 45 tons of radioactive water have leaked from a desalination facility at the Fukushima Daiichi nuclear power plant, and some of it may have reached the Pacific Ocean.
TEPCO said the trouble came in two stages, Fuji TV reported. In the morning, utility workers found that radioactive water was flooding a catchment next to a purification device. Officials said the device was then switched off, and the leak appeared to stop. But the company said it later discovered that leaked water was escaping through a crack in the catchment’s concrete wall and was reaching an external drainage ditch, Fuji reported.
Experts say that before the latest leak, the Fukushima accident had been responsible for the largest single release of radioactivity into the ocean, threatening wildlife and fisheries in the region. As much as 220 tons of water may now have leaked from the facility, according to a report in the Asahi Shimbun newspaper that cited TEPCO officials.
The water is believed to have contained up to one million times as much radioactive strontium as the maximum safe level set by the government, and about 300 times the safe level of radioactive cesium. Both are readily absorbed by living tissue and can greatly increase the risk of developing cancer.
TEPCO said it was exploring ways to stop the water from leaking through the crack and attempting to confirm whether contaminated water had reached the ocean, Fuji reported.
Japan’s nuclear agency has ordered the operator of the Fukushima Daiichi nuclear plant to explain the cause of the latest leakage of radioactive water into the ocean, and what measures will be taken to prevent a recurrence.
Officials from the Nuclear and Industrial Safety Agency inspected the situation on Monday.
Tokyo Electric Power Company discovered on Sunday that at least 45 tons of radioactive water had leaked from a purification device at the plant. The utility says the water leaked through a cracked wall of the building into a gutter that drains into the Pacific Ocean.
TEPCO says it took workers about 21 hours before they noticed the leak.
The utility says the contaminated water contained radioactive cesium. It also contained levels of radioactive strontium that could pose health risks in case of internal exposure.
TEPCO says it will take at least two weeks to analyze the strontium level in the water.
The fisheries cooperative associations in Fukushima lodged a protest with Tokyo Electric Power over the leakage.
The federation told NHK on Monday that it demanded that the utility quickly determine the level of contamination in the area affected.
More rice shipment bans in Fukushima city (NHK, Dec 5)
Scientists call for dumping radioactive soil into sea(Asahi, Dec 06)
Scientists have proposed dumping soil contaminated by radiation from the Fukushima nuclear disaster into the deep sea, an idea certain to meet opposition both at home and abroad.
A group led by Isao Tanihata, a professor at Osaka University’s Research Center for Nuclear Physics, and Kozi Nakai, a former professor at the Tokyo University of Science, said the best way to get rid of the radioactive soil is to place it in noncorrosive, pressure-tight vessels and dumping them at least 2,000 meters deep near Japan.
“The sea, away from all residents, would pose no problem,” Tanihata told about 30 researchers at a study meeting at Osaka University on Dec. 3.
The participants, including nuclear physicists and researchers at the Japan Atomic Energy Agency, did not object to the proposal from a scientific point of view.
But former education minister Akito Arima, who was also present, said, “The sea is common property of all humankind, and the key is whether fishermen and the general public will support the proposal.”
Tanihata and Nakai, who have been involved in compiling the science ministry’s soil contamination map, drafted the proposal as the government faces difficulties finding a final disposal site for soil contaminated with radioactive materials from the crippled Fukushima No. 1 nuclear power plant.
The group plans to submit a formal proposal to the government.
But it will be difficult to realize the project partly because dumping contaminated soil into the sea could constitute a violation of the London Convention, designed to prevent marine pollution.
When Japan released more than one ton of low-density radioactive water from the plant into the ocean in April, criticism arose from governments overseas.
Tanihata estimates that a highly contaminated area of 150 square kilometers northwest of the Fukushima No. 1 plant has about 750 trillion becquerels in the soil.
Tanihata said marine pollution will not worsen substantially–even if the soil is dumped directly–because its radiation levels are about 5 percent of those already released into the sea in the Fukushima nuclear accident.
He added that contaminated soil would not float even if the vessel breaks and soil spills out.
The government plans to remove radioactive materials in areas with annual radiation levels of 1 millisievert or more.
The removed soil could be stuck in temporary yards in municipalities or a temporary storage facility to be set up in Fukushima Prefecture if a final disposal site is not found.
The contaminated soil is expected to amount to 15 million to 31 million cubic meters in Fukushima Prefecture alone.
Finally, soil within no-entry zone to be surveyed (Asahi, December 01, 2011)
The central government, responding to months of criticism from experts, has decided to measure levels of radioactive cesium in soil within the no-entry zone surrounding the stricken Fukushima No. 1 nuclear power plant, sources said Nov. 30.
The central government, responding to months of criticism from experts, has decided to measure levels of radioactive cesium in soil within the no-entry zone surrounding the stricken Fukushima No. 1 nuclear power plant, sources said Nov. 30.
The government this summer examined soil within a radius of 100 kilometers of the Fukushima plant, but that did not include the area within the 20-kilometer no-entry zone.
The government will survey an additional 100 locations, including those within the no-entry zone, by the end of the year by sampling soil to a depth of 10 centimeters.
Depending on the results of the expanded survey, decontamination costs will likely increase, officials said.
The science ministry carried out the initial surveys for a month from June to create a sufficient database for decontamination work. The University of Tokyo and Osaka University were among 94 organizations that cooperated with the program.
Researchers stripped soil from a depth of 5 cm in 2,200 locations within the 100-km radius, and checked for levels of radioactive cesium. Based on the survey results, the ministry released a contamination map.
The ministry also surveyed the depth that cesium had penetrated the soil. It took samples at a depth of 20 cm in about 300 locations within the 100-km radius. At that time, however, it did not carry out survey work in the no-entry zone.
According to an analysis of samples by Osaka University, the penetration was within a depth of 5 cm in 90 percent of the 300 locations. In the remaining 10 percent, the deepest penetration reached 7 cm.
“We think the nature of soil in the no-entry zone is similar to that in surrounding areas,” a science ministry official said. “So we expect the penetration level to be almost the same.”
The government has entrusted the gathering of soil in the no-entry zone to the Federation of Electric Power Companies of Japan, an industry organization.
“As workers were not accustomed to the job (for the survey), it took time,” the ministry official said. “We also worried that they would be exposed to radiation.”
The government plans to conduct decontamination work in areas where radiation of 1 millisievert or more a year has been recorded.
By checking the cesium contamination levels in the soil, it will decide how much topsoil has to be removed.
Assuming that soil to a depth of 5 cm is removed, it will require stripping 15 million to 31 million cubic meters of dirt from Fukushima Prefecture alone.
If cesium is found to have penetrated deeper into the soil in the no-entry zone, even more soil will have to be removed. That, obviously, would cause decontamination costs to increase.
Fukushima compiles radiation cleanup policy (NHK, Dec 5) | No simple steps to carrying out decontamination work (Asahi, December 05, 2011)
FUKUSHIMA–Work to decontaminate areas around the stricken Fukushima No. 1 nuclear power plant is, if nothing else, labor-intensive, painstaking and costly…
Earlier: TEPCO: Melted fuel eroded containment vessel floor at Fukushima reactor (Asahi, December 01, 2011)
Most of the fuel rods that melted in the pressure vessel of the No. 1 reactor of the stricken Fukushima nuclear power plant dripped into the containment vessel and ate into it, according to Tokyo Electric Power Co.
It said on Nov. 30 the melted fuel did not breach the containment vessel but partially eroded its concrete floor.
As for the No. 2 and No. 3 reactors, most of the melted fuel stayed within the pressure vessel, TEPCO added.
Water levels have submerged the fuel rods at all three reactors, which is helping to cool them, the plant operator said.
TEPCO said its latest findings were based on water levels in the containment vessels, temperature readings and other data.
It admitted earlier that melted fuel partially breached the reactors, a potentially catastrophic development.
During the 1979 accident at the Three Mile Island nuclear power plant in the U.S. state of Pennsylvania, a core meltdown occurred but the pressure vessel was not breached.
TEPCO now faces the challenge of developing new technologies to recover the melted fuel for when eventual decommissioning of the reactors gets under way.
According to TEPCO’s analysis, the cooling equipment in the No. 1 reactor halted immediately after the Great East Japan Earthquake struck March 11. The fuel rods became exposed three hours after the cooling equipment stopped.
It took days before water could be pumped in from the outside. The damage to the pressure vessel was more severe there than at the No. 2 and No. 3 reactors, where it took two to three days before the fuel rods became exposed.
According to the latest analysis of the No. 1 reactor, all the fuel rods melted and ate through the pressure vessel to the containment vessel.
The melted fuel filled pits on the concrete floor of the containment vessel, eroding it to a depth of about 65 centimeters.
It would still have to eat through 37 cm of concrete to reach the steel casing of the containment vessel. Thus, a catastrophic meltdown on the scale of a theoretical “China syndrome” did not take place, TEPCO said.
The coolant water in the containment vessel is only about 30 cm deep, but that is sufficient to submerge and cool the melted fuel and is preventing further erosion, TEPCO officials added.
TEPCO said few of the melted fuel rods in the No. 2 and No. 3 reactors leaked into the containment vessel. However, an expert commissioned by the Japan Nuclear Energy Safety Organization to analyze what happened said that the situation could be much worse.
“About 70 percent of the melted fuel could have leaked to the containment vessel, although there is room for uncertainties,” the expert said.
TEPCO’s latest findings were aimed at preparing for the eventual decommissioning of the reactors. It also wanted to verify whether it could declare, by the end of the year, that a state of cold shutdown has been achieved.
But the accuracy of the findings is difficult to determine, given the difficulty of obtaining data.
TEPCO is considering the use of a special camera, resembling an endoscope, to monitor the interior of the reactors in the future.
The government’s Nuclear and Industrial Safety Agency (NISA) instructed Tokyo Electric Power Co. (TEPCO) on Dec. 5 to take measures, including installing leakage detectors, to prevent radioactive water from leaking from the crippled Fukushima No. Nuclear Power Plant after a massive amount of water containing radioactive substances was found spilling from a water processing facility there.
TEPCO, the operator of the troubled Fukushima nuclear power complex, failed to notice the water leakage for about 21 hours after it started operating the desalination facility, which had no leakage detectors, on the afternoon of Dec. 3. The government notified embassies in Japan of the mishap as there is a possibility of water containing radioactive substances flowing into the ocean.
According to the utility, the amount of leaked water inside a reactor building that houses the processing facility was about 45,000 liters, or 45 cubic meters. About 300 liters of water leaked outside the reactor building, and the water could have flowed into the ocean after leaking through a concrete crack in the building into a nearby gutter, The water near a water outlet close to the ocean contained 18 becquerels of cesium per liter on Dec. 4 — a level that is below the legal limit for releasing water into the ocean.