Group items tagged

News of radioactive cesium rice just keeps coming from Fukushima Prefecture. This time, it is from Watari District again, and the number is the highest found so far.

Radioactive cesium exceeding the national provisional safety limit (500 becquerels/kg) has been found in rice harvested in Fukushima City and other cities in Fukushima Prefecture. On December 22, the Fukushima prefectural government announced that 1540 becquerels/kg of radioactive cesium was found in rice grown by a farmer in Watari District in Fukushima Prefecture.

It is the highest level of radioactive cesium in rice detected so far. The rice is kept at the farmer's home, and not sold in the market.Well, it is the "official" highest level, and it is approaching the "unofficial" high (2600 becquerels/kg) measured in rice grown in the soil taken from Iitate-mura by Professor Kazue Tazaki of Kanazawa University. A similar amount of radioactive cesium was detected in rice grown in Iitate-mura (unofficially by an irate farmer who was forced to relocate).

Hanford officials have settled on a plan to clean up what may be the most highly radioactive spill at the nuclear reservation. It depends on calling back into service the 47-year-old, oversized hot cell where the spill occurred to protect workers from the radioactive cesium and strontium that leaked through the hot cell to the soil below. Radioactivity in the contaminated soil, which is about 1,000 feet from the Columbia River, has been measured at 8,900 rad per hour [89 sieverts per hour]. Direct exposure for a few minutes would be fatal, according to Washington Closure. [...]

In the 1980s, cesium and strontium spilled inside the hot cell, according to a 1993 report that referenced the spill. Germany needed a heat source to use for tests of a repository for radioactive waste, which emits heat, and the cesium and strontium were being fabricated into the sources. “This was concentrated material,” said Mark French, the Department of Energy’s project director for Hanford cleanup along the Columbia River. [...]

It migrated down in a open square shape, with the worst contamination down to five or six feet deep, McBride said. There is not evidence that it has reached the ground water which is about 54 feet below the ground there and about 42 feet below the bottom of the hot cell [...]

On November 15, the Ministry of the Environment announced the result of the survey of the radioactive material density in bottom soil in 193 locations in rivers, lakes and dams in Fukushima Prefecture. Radioactive cesium was detected in almost all locations, with the highest density of 60,000 becquerels/kg of radioactive cesium in the riverbed soil in the Ota River that runs through Minami Soma City, which was designated as "evacuation-ready zone" after the Fukushima I Nuclear Power Plant accident.

The Ministry also conducted the survey of the water. Maximum 27 becquerels/liter of radioactive cesium was detected in the water from a dam inside the "no-entry zone" [within 20-kilometer radius], but in most locations it was not detected. The Ministry's analysis is that "radioactive materials have been absorbed by sludge and sands and sunk to the bottom, and that is why the radiation density is high [in the soil in rivers, lakes and dams]."The survey result is not yet uploaded at the Ministry's website.The provisional "safety" standard for drinking water in Japan is 200 becquerels/liter of radioactive cesium. (For reference, in Belarus, it is 10 becquerels/kg.)

It is unconfirmed information, which may not be confirmed at all even if it is true as it may have been the "administrative guidance" from the government without a formal document. Plausible deniability has been one of Japan's forte over hundreds of years if not thousand. A resident of Fukushima City, responding to one of the tweets about why the farmers in Fukushima farmed at all this year and continue to sell produce even when they are aware that the land is heavily contaminated with radioactive fallout from Fukushima I Nuclear Power Plant, says the following:

Everyone was saying "We can't farm this year". Then the national government said to them, "Farm as usual".She also says in an earlier tweet:

I live in Fukushima City. None of the people around me eat [Fukushima produce]. Even the farmers say "We can't eat this year['s produce]". I personally believe it's "we can't eat from now on".Vegetables, meat, rice that even some people in Fukushima don't eat are being promoted and sold all over Japan.

TOKYO (Kyodo) — High levels of radioactive cesium were found in an independent study in a Fukushima city district, prompting a citizens group and others involved to urge the government on Wednesday to promptly designate the area as one of the contamination hot spots for possible evacuation and ensure proper decontamination. Up to 307,000 becquerels of cesium per kilogram of soil was detected in the Sept. 14 survey, triple that of the benchmark above which the government requires tainted mud to be sealed by concrete. The contamination is believed to have been caused by radiation leaked by the Fukushima Daiichi nuclear plant crippled in the March 11 earthquake and tsunami disaster. Extract http://mdn.mainichi.jp/mdnnews/national/news/20111005p2g00m0dm121000c.html

SOURCE: Tokyo Metropolitan Government Measures Soil Contamination in Shinjuku, EX-SKF, October 7, 2011

[...] according to the just released Ministry of Education’s aerial survey [...] most of Tokyo has less than 10,000 becquerels/square meter of radioactive cesium, with the exception of the western-most Okutama and the eastern special wards (“ku”) [...] the Tokyo Metropolitan government [...] was doing its annual survey of soil contamination in Shinjuku and quietly released the data on September 20. The soil sample was taken at Tokyo Metropolitan Institute of Public Health in Hyakunin-cho, Shinjuku-ku [...] from the surface to 5 centimeters deep [...]: Iodine-131: ND Cesium-134: 360 becquerels/kg Cesium-137: 430 becquerels/kg Total cesium: 790 becquerels/kg To convert from “per kilogram” to “per square meter”, Japan’s Nuclear Safety Commission uses the factor of 65. The total cesium per square meter in Shinjuku therefore is: 51,350 becquerels per square meter.

ABIKO, Chiba -- High levels of radiation have been detected on the premises of two elementary schools here, local education authorities have revealed. According to the Abiko Municipal Board of Education, 11.3 microsieverts of radiation per hour was detected just above the surface of the ground near a ditch in the compounds of the Abiko Municipal Daiichi Elementary School on Sept. 15. The amount was 1.7 microsieverts in the air 50 centimeters above the ground. Soil had piled up in the ditch, which had been damaged by growing tree roots, a situation similar to a residential area of the Chiba Prefecture city of Kashiwa where 57.5 microsieverts per hour was detected. Radioactive cesium amounting to 60,768 becquerels per 1 kilogram of soil was found in the ditch.

The amount of radiation 50 centimeters above the ground had declined to 0.6 microsieverts per hour by Oct. 7 after the soil was removed. The Education, Culture, Sports, Science and Technology Ministry pointed to the possibility that rain water contaminated with radioactive cesium overflowed from the ditch, soaked the nearby soil and accumulated in it. At the Abiko Municipal Namiki Elementary School, 10.1 microsieverts per hour of radiation was detected near the surface of the ground where sludge removed from its swimming pool had been buried. The school covered the area with a waterproof tarp and piled up dirt on the tarp to decrease the radiation emissions, after which 0.6 microsieverts per hour was detected 50 centimeters above the ground. The two schools have sealed off the areas where high levels of radiation were detected.

The information comes from a strange source - the husband and wife comedian couple cum independent journalists attending and reporting on TEPCO and the government press conferences when they are not on stage. In their blogpost on August 11 (in Japanese), they relate their talk with a researcher at the University of Tokyo who has submitted a scientific paper to a foreign academic society. This researcher, whom they say they cannot name because the paper is being reviewed right now, went to Fukushima and collected soil samples, rice hay samples, and water samples. He even went to the front of Fukushima I Nuclear Power Plant and collected samples there.

He also went to Iitate-mura. And he tells the couple that he found neptunium-239 in Iitate-mura, about 38 kilometers from the plant, in approximately the same amount as he found at the front gate of Fukushima I Nuclear Power Plant. That is the topic of his paper. The couple says in the very intelligent post that they cannot provide details because the paper is in review (but they also say the researcher has given them permission to talk about it in general terms), but it was in several thousand becquerels. There is no mention of whether it was per kilogram or per square meter or per something else.

There is no mention of when the researcher went to Iitate-mura. I could be wrong but the indication from the post is that it was after the news that chlorine-38 detection at Fukushima I Nuke Plant was false. TEPCO retracted the earlier announcement of chlorine-38 detection, on April 20. Uranium-239, whose half life is about 24 minutes, decays into neptunium-239 through beta decay. Neptunium-239, gamma emitter whose half life is about 2.4 days, decays into plutonium-239 whose half life is 24,200 years.

Extract Plutonium, a highly toxic radioactive substance, found in soil in places even several dozen kilometers away from the stricken Fukushima No. 1 Nuclear Power Plant had a maximum concentration equivalent to 11 and 31 percent of the levels within the premises of the plant, plant operator Tokyo Electric Power Co. said. On Friday the government released data showing varieties of plutonium were detected at six locations in Fukushima Prefecture as far as Iitate village around 45 kilometers northwest of the Fukushima complex. The government data showed the maximum concentration of plutonium 239 and plutonium 240 combined was 15 becquerels per square meter measured in the city of Minamisoma. End Extract http://mdn.mainichi.jp/mdnnews/news/20111002p2g00m0dm020000c.html

It's the same researcher who said several thousand becquerels/kg of neptunium-239 was found in the soil in Iitate-mura, about 35 km northwest of Fukushima I Nuclear Power Plant. It seems it's not just Iitate-mura that got doused with neptunium, which decays into plutonium. Date City, about 25 km northwest from Iitate-mura and 60 km from Fukushima I Nuclear Power Plant, also got a large amount of neptunium.To recap, uranium-239, whose half life is about 24 minutes, decays into neptunium-239 with a half life of about 2.5 days, which then decays into plutonium-239 whose half life is 24,200 years.

Again, the reason for withholding the information is explained in the article below as "the research paper being peer-reviewed by a foreign scientific journal" - a make-or-break event, apparently, for a young researcher at a prestigious university in Japan - and as precaution against the possible Japanese government action to squash the information. The article was written by the same husband & wife comedian couple who first wrote about neptunium in Iitate-mura on their blog magazine in early August.I'm sure the nuclear experts who have appeared on TV to soothe the populace ever since the March 11 nuclear accident has the good explanation for neptunium-239 in these locations. They've kept saying "No way plutonium will be found outside the compound, because it is heavy and it doesn't fly". Oh I get it. It's plutonium they were talking about, not neptunium which decays into plutonium. My bad.From Nikkan SPA September 13 issue (part on Date City only):

The email began thus:

The Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) has released a new map showing the spread of radiation from the crippled Fukushima No. 1 Nuclear Power Plant across 10 prefectures, including Tokyo and Kanagawa. The map released on Oct. 6 shows levels of radioactive cesium (cesium-137 and cesium-134) that have accumulated in soil in the prefectures of Yamagata, Miyagi, Fukushima, Tochigi, Gunma, Ibaraki, Saitama, Chiba, Kanagawa and Tokyo. The map shows 30,000 to 60,000 becquerels of radioactive cesium per square meter of soil in the areas of Higashikanamachi, Mizumotokoen and Shibamata in Tokyo’s Katsushika Ward, as well as some parts of Kitakoiwa in Tokyo’s Edogawa Ward.

Iitate is located 45km (28 miles) from the Fukushima Dai-ichi nuclear power plant hit by a tsunami on March 11th this year. In the mountains above the town, the forests are turning the colour of autumn. But their beauty is deceptive. Every time a gust of wind blows, Mr Sato says it shakes invisible particles of radioactive caesium off the trees and showers them over the village. Radiation levels in the hills are so high that villagers dare not go near them. Mr Sato cannot bury his father’s bones, which he keeps in an urn in his abandoned farmhouse, because of the dangers of going up the hill to the graveyard.

Iitate had the misfortune to be caught by a wind that carried radioactive particles (including plutonium) much farther than anybody initially expected after the nuclear disaster. Almost all the 6,000 residents have been evacuated, albeit belatedly, because it took the government months to decide that some villages outside a 30km radius of the plant warranted special attention. Now it offers an extreme example of how difficult it will be to recover from the disaster.

That is mainly because of the enormous spread of radiation. Recently the government said it needed to clear about 2,419 square kilometres of contaminated soil—an area larger than greater Tokyo—that received an annual radiation dose of at least five millisieverts, or over 0.5 microsieverts an hour. That covered an area far beyond the official 30km restriction zone (see map). Besides pressure- hosing urban areas, this would involve removing about 5cm of topsoil from local farms as well as all the dead leaves in caesium-laden forests.

"They scoop up soil from their gardens and dump it in holes dug out in parks and nearby forests, scrub their roofs with soap and refuse to let their children play outside. "More than three months after a massive earthquake and tsunami triggered a nuclear meltdown at a nearby power plant, Fukushima residents are scrambling to cope with contamination on their own in the absence of a long-term plan from the government. " 'Everything and everyone here is paralysed and we feel left on our own, unsure whether it's actually safe for us to stay in the city,' said Akiko Itoh, 42, with her four-year old son in her lap." Reuters

110 volunteers from all over the country with good intentions, who chose to go to one of the very high radiation area (Onami District) in Fukushima City in Fukushima Prefecture to do the decontamination work.Part of Onami District was "decontaminated" back in August as the "model" decontamination by the cleaning contractors hired by the city. In most locations, the radiation was hardly reduced, and in some locations the radiation after the "decontamination" went up. (Take a look at the results of the decon in August in my Japanese blog post.)

As you see in the photo by Yomiuri Shinbun, the district is in the mountains. Radioactive materials will continue to come from the mountains, no matter how (and how many times) they "decon" the roads and houses.But Japanese media reports the effort by the volunteers and the residents of Onami District of Fukushima City trying to decontaminate, as if it's a good thing. This one from Yomiuri Shinbun (10/29/2011):

On October 29, decontamination work started in Onami District in Fukushima Prefecture with volunteers and the residents participating.

Radioactive materials from the damaged Fukushima No. 1 nuclear plant reached the Kanto region mainly via two routes, but they largely skirted the heavily populated areas of Tokyo and Kanagawa Prefecture, an expert said. Relatively high levels of radioactive cesium were detected in soil in northern Gunma and Tochigi prefectures and southern Ibaraki Prefecture after the Fukushima No. 1 nuclear power plant was damaged by the March 11 Great East Japan Earthquake and tsunami. But contamination was limited in Tokyo and Kanagawa Prefecture, where 22 million people live. Hiromi Yamazawa, a professor of environmental radiology at Nagoya University, said the first radioactive plume moved through Ibaraki Prefecture and turned northward to Gunma Prefecture between late March 14 and the afternoon of March 15.

Large amounts of radioactive materials were released during that period partly because the core of the No. 2 reactor at the Fukushima No. 1 plant was exposed. "The soil was likely contaminated after the plume fell to the ground with rain or snow," Yamazawa said, adding that western Saitama Prefecture and western Tokyo may have been also contaminated. Rain fell in Fukushima, Tochigi and Gunma prefectures from the night of March 15 to the early morning of March 16, according to the Meteorological Agency. The second plume moved off Ibaraki Prefecture and passed through Chiba Prefecture between the night of March 21 and the early morning of March 22, when rain fell in a wide area of the Kanto region, according to Yamazawa's estimates.

He said the plume may have created radiation hot spots in coastal and southern areas of Ibaraki Prefecture as well as around Kashiwa, Chiba Prefecture. Yamazawa said the plume continued to move southward, without approaching Tokyo or Kanagawa Prefecture, probably because winds flowed toward a low-pressure system south of the Boso Peninsula. "It rained slightly because the low-pressure system was not strong," said Takehiko Mikami, a professor of climatology at Teikyo University. "Contamination in central Tokyo might have been more serious if (the plume) had approached more inland areas." According to calculations by The Asahi Shimbun, about 13,000 square kilometers, or about 3 percent of Japan's land area, including about 8,000 square kilometers in Fukushima Prefecture, have annual exposure levels of 1 millisievert or more.