Tokyo Electric Power Co. said Monday that it has detected radioactive cesium in groundwater samples taken from the premises of the crippled Fukushima Daiichi nuclear complex, reversing an earlier announcement that any contamination was negligible.
The announcement came as TEPCO is trying to secure the understanding of local fishermen over the dumping in the Pacific Ocean of groundwater that has been pumped out from wells at the site, saying it has confirmed that concentrations of radioactive substances are sufficiently low.
TEPCO had said radioactive cesium in the groundwater was at a level that could not be detected by an instrument at the Fukushima Daiichi complex. But the same sample was found to contain 0.22 becquerel of cesium-134 and 0.39 becquerel of cesium-137 per liter when checked at the Fukushima Daini plant, where radiation levels are lower.
Radioactive cesium from the crippled Fukushima No. 1 nuclear plant may have reached as far as Hokkaido, Shikoku and the Chugoku region in the west, according to a recent simulation by an international research team.
Large areas of eastern and northeastern Japan were likely contaminated by the plant, with concentrations of cesium-137 exceeding 1,000 becquerels per kilogram of soil in some places, says the study, which was posted Monday on the website of the National Academy of Sciences.
Researchers for the U.S.-based organization said the study, which was based on partial data readings, is the first to estimate potential cesium contamination across the country. But they also played down the incident’s impact on the three distant regions.
The science ministry’s latest aerial monitoring over Chiba and Saitama prefectures in September confirmed that radioactive cesium released from the Fukushima No. 1 power plant has contaminated parts of the Kanto region.
A ministry report released Thursday revealed that contamination was found in northern Chiba, including the cities of Kashiwa, Matsudo and Abiko, and in the mountainous areas of Chichibu in Saitama Prefecture’s west and Misato in the prefecture’s east.
The highest contaminated areas contained between 60,000 to 100,000 becquerels of cesium-134 and -137 per square meter, it showed. Cesium-134 has a half-life of two years and the one for -137 is 30 years.
A sample of unharvested rice contained 500 becquerels of cesium per kilogram, they said. Radioactive cesium was spewed from the Fukushima Dai-ichi nuclear power plant after it was damaged by a massive earthquake and tsunami on March 11.Under Japanese regulations, rice with up to 500 becquerels of cesium per kilogram is considered safe for consumption.Officials have tested rice from more than 400 spots in Fukushima prefecture. The highest level of cesium previously found was 136 becquerels per kilogram, prefectural official Kazuhiko Kanno said.
Radioactive cesium that was released into the ocean from the Fukushima No. 1 nuclear plant is likely to flow back to Japans coast in 20 to 30 years after circulating in the northern Pacific Ocean in a clockwise pattern, researchers said Wednesday.Researchers at the Meteorological Research Institute and the Central Research Institute of Electric Power Industry estimated that the amount of radioactive cesium-137 that was directly released into the sea came to 3,500 terabecquerels from March to the end of May, while estimating that roughly 10,000 terabecquerels fell into the ocean after it was released into the air.
Radioactive cesium exceeding the legal limit has been detected in four tea products that reached the market and were made with tea leaves from Saitama and Chiba prefectures, a recent health ministry inspection showed.
One of the products, using tea leaves from Chiba Prefecture, contained 2,720 becquerels of cesium per kilogram, far above the government-set limit of 500 becquerels, the Health, Labor and Welfare Ministry said Friday.
The three other products, made with tea leaves from Saitama Prefecture, were found to contain between 800 and 1,530 becquerels of cesium. It is the first time cesium exceeding the maximum limit has been detected in Saitama tea leaves.
The amount of radioactive cesium ejected by the Fukushima reactor meltdowns is about 168 times higher than that emitted in the atomic bombing of Hiroshima, the government’s nuclear watchdog said Friday.
The Nuclear and Industrial Safety Agency provided the estimate at the request of a Diet panel but noted that making a simple comparison between an instantaneous bomb blast and a long-term accidental leak is problematic and could lead to "irrelevant" results.
The report said the crippled Fukushima No. 1 plant has released 15,000 terabecquerels of cesium-137, which lingers for decades and can cause cancer, compared with the 89 terabecquerels released by the U.S. atomic bombing of Hiroshima.
A research agency in Fukushima Prefecture has begun testing about 110 varieties of Japanese and foreign rice in a search for strains that absorb less radioactive cesium from the soil.
The project, which was initiated by the Fukushima Agricultural Technology Center in Koriyama, after the meltdowns and explosions at the Fukushima No. 1 power plant, is unprecedented in that no research has ever been done on rice grown on land tainted by relatively high amounts of radioactive matter, the center’s research team said.
The research is important since the radioactive fallout from the Tokyo Electric Power Co. plant will likely disrupt rice farming in nearby areas for years to come, it said.
The rice harvest is traditionally a time of festivities celebrated even by the Emperor, as farmers reap the rewards of four months of labor in a 2,000-year-old tradition. But not this year, with radiation seeping into the soil.
Farmers growing half of the nation’s rice crop are awaiting the results of tests to see if their produce has been contaminated by radiation from Tokyo Electric Power Co.’s wrecked Fukushima No. 1 nuclear plant. Rice, used in almost all meals and the key ingredient in sake, is being tested before the harvest starts this month. Radiation exceeding safety levels has so far been found in produce including spinach, tea and beef.
Shigehide Oki, a 61-year-old farmer near Tokyo, this week passed the first hurdle after a preliminary round of tests showed no trace elements of radioactive cesium, the main source of concern. Losing his crop of about 80 tons of rice would "destroy" him, he said.
Radiation fallout from the wrecked Fukushima nuclear plant poses a growing threat to Japan’s food chain as unsafe levels of cesium found in beef on supermarket shelves were also detected in more vegetables and the ocean.
More than 2,600 cattle have been contaminated, Kyodo News reported July 23, after the Miyagi local government said 1,183 cattle at 58 farms were fed hay containing radioactive cesium before being shipped to meat markets.
Agriculture Minister Michihiko Kano has said officials didn’t foresee that farmers might ship contaminated hay to cattle ranchers. That highlights the government’s inability to think ahead and to act, said Mariko Sano, secretary general for Shufuren, a housewives organization in Tokyo.
“The government is so slow to move,” Sano said. “They’ve done little to ensure food safety.”