23,300 Bq/Kg of Radioactive Cesium from a Mix of Wet Soil and Dead Leaves in Mizumoto Park in Tokyo

(Sorry, you can't just multiply the number by 65 and compare it to the Chernobyl evacuation level. Read on to find out why.)

The Mizumoto Metropolitan Park is located in the eastern Tokyo with elevated radiation levels. The Communist Party delegation of Tokyo Metropolitan Assembly, who has done the survey of radiation levels in Tokyo from very early on in the nuclear crisis, released the result of the latest survey in one of the Metropolitan parks in Tokyo.

The survey found 23,300 becquerels/kg of radioactive cesium from a wet mix of dirt and dead leaves in one location in the Mizumoto Park in Katsushika-ku, Tokyo (No. 4 location in the table posted below).

The delegation did three tests at this location with 2 samples taken on February 15. The third test was done on February 18 by combining the two samples taken on February 15 and tested on February 16 and 17.

It may be important to note that the Communist Party delegation tested the top 1 centimeter of the soil, and the top 1 to 2 centimeters of the soil and dead leaves mixture. The measured numbers may therefore be higher than the samples taken from the top 5 centimeters, which is a normal procedure in the government tests.

To derive "becquerel/square meter" from "becquerel/kg", you multiply "becquerel/kg" number by 65, but that only applies if the soil is taken from the top 5 centimeters. (Ibaraki Prefecture's measurement page as reference, here.)

From the Communist Party delegation of Tokyo Metropolitan Assembly website (English translation is mine; the last two rows are the reference):

According to Yomiuri Shinbun article (2/22/2012), "the Ministry of Education and Science sets the standard of radiation that requires decontamination as locations that test "1 microsievert/hour higher than the surrounding areas", and the Tokyo Metropolitan Bureau of Environment says "There is no need for decontamination at this point.""

Never mind that the Ministry of Environment's decon standard is 0.23 microsievert/hour.

The surface radiation levels and the air radiation levels at 1 meter off the ground all exceed 0.23 microsievert/hour. The highest surface radiation level was 1.54 microsievert/hour, and the highest radiation level at 1 meter was 0.74 microsievert/hour.

Before the nuclear accident, the average background radiation level in Tokyo was slightly above 0.03 microsievert/hour. That was the level right before something very radioactive arrived from Fukushima on March 15, 2011 sometime between 4AM and 4:59AM. (See the Tokyo Metropolitan government's own measurement, here, as the radiation in Shinjuku went from 0.0347 microsievert/hour average between 3AM and 3:59AM to 0.1 microsievert/hour average in the next hour. )

What the Tokyo Metropolitan government needs to do is to scrape 1 centimeter of the soil under the trees and shrubs and remove dead leaves to lower the radiation. But they openly say they are not going to do anything.

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(UPDATE from Kontan Bigcat on Twitter: the 65 multiplier applies only to soil taken from 5 centimeters AND with the soil density (dry) of 1.3 gram/cubic centimeter.

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91,600 Bq/Kg of Radioactive Cesium from Sunflowers in Iitate-mura, Fukushima

So the sunflowers DID concentrate radioactive cesium in soil. It was not where the Japanese government wanted you to find.

According to one Iitate-mura villager, Mr. Itoh, who had his sunflowers tested, the radioactive cesium was IN THE ROOTS. He suspects that the government knew, and cherry-picked the data that seemingly supported the foregone conclusion that sunflowers do not work in decontaminating the soil.

Why? Because the government wants and needs to distribute big money to big businesses that closely work with the government in the "decontamination" bubble that they've created.

From his tweets on February 7, 2012:

ヒマワリの根　セシウム１３４　39,500ｂｑ／ｋｇ セシウム１３７　　52,100ｂｑ／ｋｇ セシウム計　　91,600ｂｑ／ｋｇ。ヒマワリの根の灰については、焼却温度が低く、体積が１／４程度にしか減らなかった、２，２００ｇの根を燃やし４６０ｇの灰が出た。

Sunflower roots: Cesium-134, 39,500 Bq/kg; cesium-137, 52,100 Bq/kg; total 91,600 Bq/kg. Since the roots were burned at low a temperature, the roots were reduced to only one-quarter in mass. 2,200 grams of the roots were burned, resulting in 460 grams of ashes.

焼却温度が高ければ１／１００、とすると２００万ｂｑ？。農水省は税金を投入し大臣自ら植えたヒマワリの実験畑の除染効果は無いと断言したが、ある思いを持っての実験、効果なしの結論を前提にしたものだったから。農水省の放射性廃棄物の検査は何故か“根”を外しているから。

If they were burned at a higher temperature, maybe the concentration would be 100 times, resulting in about 2 million Bq/kg of radioactive cesium, maybe? After pouring in taxpayers' money and the minister himself planting sunflowers in the experimental plot in the village, the Ministry of Agriculture, Forestry and Fisheries has declared sunflowers have no decontamination properties. It is because that conclusion was pre-determined with one purpose in mind. The ministry's test of radioactive wastes inexplicably excluded the sunflower "roots".

ヒマワリに除染されたのでは利権が発生しない、要は利権が簡単に得られる従来型の公共工事による“除染”こそ懐を簡単に肥やす方法だから。１０００年に一度の大震災でも役人や政治家が考えることはこの程度。誰だこの程度の政治家を選んだのは。

If sunflowers could decontaminate, there would be no subsidies and handouts. In essence, "decontamination" via the public works loaded with pork is the easiest way to get rich quick. Even in the face of the biggest disaster in 1,000 years, that's the level where the bureaucrats and politicians operate. Who elected these pols?

Mr. Itoh no doubt knows well it is the Japanese people who elected these pols and keep electing them, but that doesn't mean Mr. Itoh himself is complicit. He may have voted to oust these politicians in his district, in vain.

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Radioactive Strontium Found in Central Tokyo

(UPDATE-2) Asahi Shinbun carried the news:



(UPDATE) So far, it is dead silence from the Japanese MSMs; even the critical papers like Tokyo Shinbun is mum on strontium in Tokyo.

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A citizen group did the soil survey of three locations in central Tokyo, and had the soil samples tested for radioactive cesium and strontium. All three had both.

Summary of reporting by Yasumi Iwakami, independent journalist:

Locations and amounts of radioactive materials:

Kiyosumi Shirakawa Station, Koto-ku:
Radioactive cesium (134 and 137 combined): 19,126 Bq/kg
Radioactive strontium (89 and 90 combined): 44 Bq/kg

Yurakucho Station, Chiyoda-ku:
Radioactive cesium (134 and 137 combined): 20,955 Bq/kg
Radioactive strontium (89 and 90 combined): 51 Bq/kg

Front of the Ministry of Economy, Trade and Industry, Chiyoda-ku:
Radioactive cesium (134 and 137 combined): 48,176 Bq/kg
Radioactive strontium (89 and 90 combined): 48 Bq/kg

It's a poetic justice that the amount of radioactive cesium is the highest at METI. I hear TEPCO's headquarter building in Tokyo also enjoys rather high radiation.

Iwakami cautions that radioactive strontium may be confirmed to have come from Fukushima only after the detailed analysis at a laboratory that can separately measure strontium-89 and strontium-90. The presence of cesium-134 seems to prove that at least radioactive cesium found in the soil samples is of Fukushima origin.

I believe there is only one or two laboratories in Japan that does that; one of them is the laboratory that TEPCO uses for the radionuclide analysis (Japan Chemical Analysis Center).

It looks like the national government may make a comment or two on this discovery later, some people are hoping that the government does. What would the government say? Let me guess... How about "No immediate effect on health", and "We should only worry about cesium, forget the rest".

By the way, you may recall the discovery of radioactive strontium on the rooftop of an apartment building in Kohoku-ku in Yokohama City in October. There has been no response from the city to the citizen who measured it, and no action from the city whatsoever on removing the highly radioactive sediment from the rooftop or decontaminating.

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Now They Tell Us: Cesium-137 Soil Deposition May Be Much Wider Than Thought, Hokkaido and Western Japan May Have "Hot Spots"

Not the news that weary radiation-vigilant residents of Japan (including Tokyo Brown Tabby) wanted to hear.

But according to a new research paper by the international team of scientists to be published on the electronic version of the Proceedings of the National Academy of Sciences of the United States of America (PNAS), cesium-137 (half life 30 years) may have deposited in the soil in much wider areas including Hokkaido, Chubu, Chugoku, Shikoku in one month starting March 20. The cesium deposition in these regions is considered to be in much lower concentration than in Tohoku or Kanto, but the researchers say there may be radiation "hot spots" in these regions.

It's no surprise to anyone who used to look at the dispersion simulations by Austria's ZAMG, Germany's DWD and Norway's NILU in the early days of the nuclear crisis in March, April and May. I remember seeing large plumes engulfing Hokkaido a number of times, and occasional small plumes swiping Shikoku.

From Jiji Tsushin News (11/15/2011; links added):

東京電力福島第1原発事故で放出された放射性物質のうち、半減期が約30年と長いセシウム137が、3月20日からの1カ月間に中部や中国、四国地方の山 岳地帯や北海道の土壌に沈着した可能性があることが分かった。米大学宇宙研究協会（USRA）や名古屋大、東京大などの国際チームが14日までに行ったシ ミュレーションの結果で、米科学アカデミー紀要電子版に発表される。

Of radioactive materials released from the Fukushima I Nuclear Power Plant accident, cesium-137, whose half life is 30 years, may have deposited in the soil in the mountains in Chubu and Shikoku regions, and Hokkaido, in a month starting March 20. It is a conclusion from the simulation done by the international team of scientists including those from the USRA (Universities Space Research Association), Nagoya University, and Tokyo University. Their paper will be published in the electronic version of the Proceedings of the National Academy of Sciences of the United States of America.

　これらの地域の大半は人体に影響を及ぼしたり、除染が必要だったりする汚染濃度ではないと推定される。ただ、局所的に濃度が高いホットスポットが存在する可能性があり、詳細な調査が必要という。

It is assumed that most of these areas do not have the level of contamination that may affect the health or may require decontamination. However, there may be "hot spots" with locally high radiation, and a detailed investigation may be necessary, according to the scientists.

　USRAの安成哲平客員研究員や名大の安成哲三教授、東大の早野龍五教授らは、ノルウェーで開発された地球全体の大気輸送モデル（20キロ四方単位）とヨーロッパ中期予報センターの気象データ、文部科学省の降下物観測データを組み合わせシミュレーションした。

Teppei Yasunari of USRA, Tetsuzo Yasunari of Nagoya University, and Ryugo Hayano of Tokyo University combined the global atmospheric transfer model (20-kilometer grid) developed in Norway, the meteorological data from European Centre for Medium-Range Weather Forecasts (ECMWF) [in Redding, UK] and radiation fallout measurement data from Japan's Ministry of Education and Science to do the simulation.

　その結果、日本列島へのセシウム137沈着量は1カ月間で1000テラ（テラは1兆）ベクレル以上と推定された。福島県を中心に東北、関東の太平洋側の 沈着量が多いのは文科省の航空機モニタリング結果などと一致したが、中部、中国、四国の山岳地帯や北海道でも、低気圧が通過した際に同原発からセシウム 137の微粒子を含む風が流入し、雨で沈着した可能性が示された。　

According to their simulation, the cesium-137 deposition in Japan was estimated to be more than 1,000 terabecquerels in one month [starting March 20]. The simulation matched the result of the aerial survey by the Ministry of Education that showed the Pacific Ocean side of Tohoku and Kanto had a larger amount of cesium deposition. However, the simulation also shows that when the low pressures passed over the mountain areas in Chubu, Chugoku and Shikoku regions and in Hokkaido, wind that contained cesium-137 particles from Fukushima I Nuclear Power Plant may have blown and the particles may have fallen with the rain and deposited in the soil.

The paper is here: http://www.pnas.org/content/early/2011/11/11/1112058108.full.pdf

From the "Discussion" section of the paper (page 4, left column)

...we expect the true soil contamination across Japan to be considerably more variable than in our estimate. Even in regions where we find relatively low soil contamination levels, hot spots with high concentrations (e.g., due to convective rain fall, orographic enhancement of rainfall, or fine-grain soil flow by rainwater on the ground) may be possible. In contrast, relatively clean patches may also be present in areas with high overall contamination levels.

Supplementary information and data: http://www.pnas.org/content/suppl/2011/11/14/1112058108.DCSupplemental/pnas.1112058108_SI.pdf

From Page 5 of the supplementary data above, "Estimated Cs137 Concentration in Soil" (screen shot from a movie)

"Movie S4. Estimated 137Cs concentration range in soil using DRT of 0.001 and conversion coefficient (CC) of 38, 53, and 68 kgm−2 over Japan. CCs of 38, 53, and 68 kgm−2 correspond to −1σ, mean value, and þ1σ in Fig. S5, respectively. Outputs 0.2° × 0.2° were interpolated into finer resolution using cubic interpolation. The Merged IBCAO/ETOPO5 Global Topographic Data Product (1) was used to mask out ocean area below 0 m above sea level (a.s.l.)."

The movie can be seen here.

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Ministry of Education Map on Tellurium-129m, Silver-110m in Soil in Fukushima

The Ministry of Education and Science announced on October 31 the "result" of the survey they did in June. Much like announcing the result in July (2PM on July 29, to be exact) of the survey they did in March about radioactive fallout in Tohoku and Kanto, where radioactive iodine, cesium tellurium and silver were found in abundance in Tokyo (see my post on August 1).

So, if tellurium and silver fell in Tokyo, it is very small wonder that they were in Fukushima soil within the 100-kilometer radius of Fukushima I Nuclear Power Plant.

Maps from the Ministry's announcement on October 31 are as follows. The amounts of tellurium and silver have been adjusted to the amounts as of June 14. I re-oriented and enlarged the maps for easier viewing but the resolution is not that great.

Tellurium-129m, half life about 34 days (the unit is becquerels/square meter):

Silver-110m, half life about 250 days (becquerels/square meter):

Silver-110m probably came from melted control rods, and went all the way to Tokyo.

The announcement is NOT accompanied by the table that has actual measurements at these locations. But Mainichi Shinbun (10/31/2011) reports that the highest amount of tellurium-129m was found in Okuma-machi at 2.66 million becquerels/square meter.

The Ministry's fallback position of course is "they won't affect the health very much because the radiation from these nuclides is "small" compared to those from radioactive cesium.

Sure. They are shorter-life nuclides, which means radioactivity is stronger. Even if they simply pass through the body without accumulation, I would think they zap the body with radiation as they pass through. External exposure is another matter. I fearfully recall that many kindergarteners and elementary school pupils all over Tohoku and Kanto were made to plant rice with bare feet and hands back in April and May. (And they are made to dig up the sweet potatoes with bare hands now.)

What's interesting is the third map which plots the ratio of tellurium-129m to cesium-137. The tellurium-129m ratio is very pronounced south of Fuku-I nuke plant, toward Iwaki City and southern Ibaraki Prefecture:

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#Radiation in Japan: 80 to 120 Microsieverts/Hr Bush in Koriyama City, Fukushima

It's been over 7 months since the Fukushima I Nuclear Power Plant accident started, and it does look like natural concentration of radioactive materials may be happening in eastern Japan.

57.5 microsieverts/hour radiation from the soil in the city-owned land in Kashiwa City, Chiba sounded extraordinarily high when first reported, but maybe not so.

Fukushima Chuo Television (FCT) reported that the radiation level near the ground in a bush right by the railroad station was found to be 80 to 120 microsieverts/hour in Koriyama City, Fukushima Prefecture.

It is also possible that the radiation on that particular spot has always been high, and is being discovered only now, as more citizens are armed with personal survey meters measuring everywhere.

Koriyama City is 60 kilometers west of Fukushima I Nuclear Power Plant. Kashiwa City is 200 kilometers south, in the Tokyo Metropolitan suburb.

From FCT news (10/27/2011):

きょう午後、ＪＲ郡山駅前の植え込みの土から、１時間あたり８０マイクロシーベルトを超える放射線量が計測されました。

This afternoon, radiation exceeding 80 microsieverts/hour was detected from the soil near the roadside bush near the JR Koriyama station.

　高校生などが通学で利用する場所で、早急な現地からの除去が求められます。

High school students use the road for commuting. Immediate decontamination is desirable.

　きょう午後、ＪＲ郡山駅西口にある植え込みの土から、高い放射線量が確認されたとＦＣＴに情報が寄せられました。

This afternoon, a viewer informed FCT that a high level of radiation was confirmed on the soil near the bush located near the west entrance of JR Koriyama station.

　ＦＣＴが現地で計測したところ、地上から５センチほどのところでは、最大で１時間あたり８０マイクロシーベルトを計測しました。

FCT went and measured the radiation, and it was maximum 80 microsieverts/hour at 5 centimeters off the ground.

　また、ＪＲの職員が個人で持っていた線量計で調べたところ、１２０マイクロシーベルトの高い放射線量であることがわかりました。

Also, when we measured the same spot with a personal survey meter of a JR personnel, it registered 120 microsieverts/hour.

　高い値の放射線量が確認された場所は、土の色が変わっていて、線量が高いのもこの場所だけとみられています。

The soil at this location looks to have a different color [from the soil in the area nearby], and it is considered that the high radiation is only at this location.

　現場は駐輪場近くにあり、通学の高校生などが数多く通ることから、早めの処理が待たれます。
　郡山市は現地に職員を送り、詳しく調査しています。

The location is near the bicycle parking lot, and many high school students use the road. The quick response from the authorities is desired. Koriyama City is sending the city personnel to investigate further.

If someone stays on that spot with 80 microsieverts/hr 24 hours a day for one year, the external radiation would be 700 millisieverts.

By mentioning the soil is in a different color, FCT may be indicating that someone brought the highly contaminated soil and dumped it there. It could be. But that was the suspicion for the Kashiwa City's spot, too, which proved to have been wrong.

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New "Decon" Experiment in Iitate-Mura: Burn Radioactive Soil

The Japanese government has just started a new experiment in the very highly contaminated Iitate-mura in Fukushima Prefecture where the soil contamination exceeds 50,000 becquerels/kg of radioactive cesium, with a host of other nuclides including strontium and neptunium which has since decayed into plutonium.

What's the experiment? To burn the radioactive soil to reduce the bulk for disposal.

What's this Japanese obsession with "decontamination" and with "incineration"? Do they think they can somehow "purify" the radioactive fallout by burning? (Hint: this is a rhetorical question. Answer is yes of course.)

The nuclear researchers at the government's JAEA seem to think burning the soil will revive the soil.

It will kill the soil.

From Kyodo News Japanese (10/26/2011):

東京電力福島第１原発事故で汚染された田畑の再生に向け、日本原子力研究開発機構（茨城県東海村）は２６日、福島県飯舘村で、農地の土壌を焼却し、放射性セシウムの除去効果を確認する新たな実証試験を公開した。

On October 26, Japan Atomic Energy Agency (located in Tokai-mura, Ibaraki Prefecture) showed off its new experiment to see if radioactive cesium could be effectively removed by burning the farm soil in Iitate-mura in Fukushima Prefecture. The experiment is aimed at reviving the farm fields contaminated by the Fukushima I Nuclear Power Plant accident.

　農林水産省から委託された土壌改良技術開発の一環で、農業・食品産業技術総合研究機構（茨城県つくば市）との共同研究。測定結果は２～３週間後に判明する予定。

It is part of the soil remediation technology development as assigned by the Ministry of Agriculture, Forestry and Fisheries. JAEA and National Agriculture and Food Research Organization (in Tsukuba City, Fukushima Prefecture) are jointly conducting the research. The result of the experiment will be known in 2 to 3 weeks.

　農水省によると、福島県で土壌１キログラム当たり５千ベクレル以上の農地全ての表土を削り取ると、東京ドーム２、３杯分の約３００万トンになると推定され、残土の処理が難題となっている。

According to the Ministry of Agriculture, if all the farm soil with 5000 becquerels/kg and higher [of radioactive cesium] is removed in Fukushima Prefecture, it would fill 2 to 3 Tokyo Domes, or about 3 million tonnes. How to dispose the removed soil is a big issue.

Let's assume the lowest number, 5,000 becquerels/kg of radioactive cesium in the Fukushima farm soil. 1 tonne is 1000 kilograms. So,

• 1 tonnes contains: 5 million becquerels of radioactive cesium

• 3 million tonnes contains: 1.5 x 10^13, or 15 terabecquerels, or 15,000,000,000,000 becquerels.

If the national government's much-publicized past experiments (like planting sunflowers to absorb radioactive materials in soil) in Iitate-mura are any indication, this one may also fail.

Besides, by strongly encouraging farmers outside the no-entry evacuation zone and the planned evacuation zone (like Iitate-mura) in Fukushima to grow crops as usual, the soil was probably turned deep, mixing radioactive materials with deeper, clean soil. So, removing the top 5 centimeters are likely to do hardly anything other than making people feel good that they have done the "decontamination".

There are areas and spots with high radiation outside Fukushima Prefecture, but those are none of the concern for the national government, although it has said it may consider the national-level decontamination for the areas with expected annual radiation exposure (external only) of more than 1 millisievert.

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Tokyo Metropolitan Government Measures Soil Contamination in Shinjuku

And it is higher, much higher than the Ministry of Education's aerial survey indicates.

First, to recap, according to the just released Ministry of Education's aerial survey of radioactive cesium deposition in Tokyo, 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") bordering Chiba Prefecture to the east.

Now, it turns out that the Tokyo Metropolitan government, who is not so eager to measure anything radioactive since March 11, 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, as it has always been done. (That's where the official air radiation level is monitored every day for Tokyo.)

For the last 5 years, radioactive iodine and cesium-134 were not detected, and cesium-137 was 2 to 3 becquerels per kilogram.

Now, this year, the numbers for the soil from the surface to 5 centimeters deep were:

• 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.

Even if you just take cesium-137 (for comparison purpose), 430 becquerels/kg translates to 27,950 becquerels/square meter.

The Tokyo Metropolitan government also found cesium-134 and cesium-137 in the soil between 5 and 15 centimeters deep. For the past 5 years, iodine-131 and cesium-134 were ND, and cesium-137 was 2 to 3 becquerels/kg.

But this year:

• Cesium-134: 4.2 becquerels/kg

• Cesium-137: 7.1 becquerels/kg

• Total cesium: 11.3 becquerels/kg
  

However, true to form, the Tokyo Metropolitan government says it is in agreement with the Ministry of Education's survey of air radiation level. The government says the air radiation at the sample location is not that high (0.07 microgray/hr) therefore no decontamination of a wide area will be necessary. (Mr. Governor, we are talking about soil deposition here, not the air radiation level.)

The air radiation the Institute measures at 18 meters off the ground was 0.0563 microgray/hr that day, according to the announcement. The Tokyo Metropolitan government uses microgray as equivalent to microsievert.

It goes to show that the aerial survey with 300 to 600 meter radius and averaging out the numbers doesn't locate high radiation hot spots in the cities like Tokyo or Yokohama. Or anywhere else for that matter. And this Shinjuku location is not considered to be particularly hot.

Here's the screen capture of the Tokyo Metropolitan government announcement, with highlight:

(H/T savechild.net for the info and the screen capture)

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Soil Survey of Watari District, Fukushima City Shows 5 Times Cesium Concentration in One Location

compared to the survey done in June.

From Professor Tomoya Yamauchi's survey result dated October 5, 2011, as published by the "FoE Japan":

Survey results 計測結果

(1) Ogura-ji Inariyama 小倉寺稲荷山
Cs-134: 604.66 eV; 108,450 +/- 247 Bq/kg
Cs-137: 661.64 eV; 131,250 +/- 282 Bq/kg
Total 総計：239,700 +/- 375 Bq/kg

(2) Hachiman Jinja 八幡神社
Cs-134: 604.66 eV; 71,293 +/- 171 Bq/kg
Cs-137: 661.64 eV; 85,981 +/- 198 Bq/kg
Total 総計：157,274 +/- 262 Bq/kg

(3) Storm drain on the school route 通学路西側住宅雨水枡
Cs-134: 604.66 eV; 44,294 +/- 135 Bq/kg
Cs-137: 661.64 eV; 54,010 +/- 156 Bq/kg
Total 総計：98,304 +/- 206 Bq/kg

(4) drain in Yakushi-cho 薬師町内の溝
Cs-134 604.66 eV; 137,490 +/- 236 Bq/kg
Cs-137 661.64 eV; 170,075 +/- 274 Bq/kg
Total 総計：307,565 +/- 361 Bq/kg

(5) backyard of a residence in Yakushi-cho 薬師町内民家の庭
Cs-134: 604.66 eV; 17,532 +/- 91 Bq/kg
Cs-137: 661.64 eV; 20,932 +/- 104 Bq/kg
Total 総計：38,464 +/- 138 Bq/kg

The location (1) is the one whose cesium concentration in the soil quintupled from the measurement in June of 46,540 Bq/kg of radioactive cesium.

The location (2) is right next to a nursery school with small children.

Professor Yamauchi's conclusion:

地域全体が非常に高いレベルで汚染している。側溝の泥を取除く程度の除染では線量は下がらない。各住宅や空き地の表土とともに、アスファルトやコンクリート、コンクリート塀、屋根も除去の対象にしなければ線量は下がらないと見られる。

The entire district is highly contaminated. The radiation level will not go down with decontamination that only involves removing the sludge from the drains. In addition to removing the top soil at houses and empty lots, asphalt, concrete, concrete fences and roofs would have to be removed in order to lower the radiation level.

The national government did survey the district, but managed to miss high radiation locations. It did only the air radiation survey, which does not necessarily reflect the contamination level of the ground.

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#Radiation in Japan: 300,000 Bq/Kg of Radioactive Cesium from Soil in Fukushima City

NGO "FoE Japan (Friends of Earth Japan) did its own survey of radiation contamination in Watari District in Fukushima City with the help from Professor Tomoya Yamauchi of Kobe University. Watari District has high radiation levels throughout the district, but the national government has so far refused to designate anywhere in the district as "evacuation recommended" area.

If the government designate an area as such, the government has to pay for the relocation cost. As the result, the designation in other cities like Date City has been very arbitrary and spotty, rendering the whole exercise worthless. Often, the residents are simply moved to the other parts of the same city with slightly lower radiation.

Professor Yamauchi already released the result of the air radiation survey of Watari District, but today (October 5, 2011) FoE Japan held a press conference and announced the result of the soil contamination survey.

The links at the NGO's site are broken unfortunately, but the newspapers reporting the press conference, the highest contamination was 300,000 becquerels/kg of radioactive cesium. Here's one from Asahi Shinbun (10/5/2011), which is one of the better Japanese newspapers that tend to keep the links alive longer.

Judging from Professor Yamauchi's air radiation survey (in Japanese), this particular location looks like the one that had 23 microsieverts/hour radiation at 1 centimeter off the surface of the dirt in the roadside drain. Professor Yamauchi hypothesized that radioactive cesium from surrounding mountains and forests washes down the drain after the rain, and naturally gets concentrated in the dirt.

In my communication with Professor Yamauchi, I asked if the decontamination as currently practiced in Fukushima works at all, given the non-result in Watari District which he surveyed. He said the spot decontamination like removing the dirt and sludge is useless as radioactive materials simply come from somewhere else, so the district-wide decontamination including the surrounding mountains would be necessary to "decontaminate" in the true sense of the word - to remove radioactive materials, not reduce.

He also said that spraying water with high-pressure washers hardly work at all on concrete and asphalt surfaces, as radioactive cesium is now deeply embedded in the concretes and asphalt. The only way to decontaminate concrete and asphalt, the professor said, was to physically remove all concrete structures - houses, fences, pavement, etc., which he said would destroy the neighborhood. He is of the opinion that all the residents in the district should be evacuated first, with the government paying for the cost, and the experts should get to work to truly "decontaminate".

Professor Yamauchi also wryly observed the the word for "decontamination" in Japanese, 除染 (jo-sen), is misleading. Looking at the characters for the word, it does mean "removing the contamination". So by doing the "jo-sen" work people think they are removing the contamination, when all they may achieve is to reduce the level of contamination somewhat (not much, if Watari District is any indication). He even said it was as if the government was encouraging "decontamination" so as not to evacuate people.

Or in the case of Minami Soma City, it is as if the residents in contaminated areas could feel comfortable enough to remain there by doing the "decontamination" work, as one volunteer related in the US ABC News interview in August. "If this radiation is going to stick around here for five to 10 years, we have to learn to live with it,"she said, instead of moving away from the high radiation area. For her, shoveling dirt from the kindergarten playground was a way to live with "it".

17,000 people live in Watari District, with beautiful mountains and water. It is dubbed "hidden paradise" in Fukushima City for the scenery like this:

(Photo credit: SHEjapan.com, with permission)

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#Radiation Map by Ministry of Education: Gunma Looks Worse Than Expected

On September 27 the Ministry of Education and Science announced the result of their latest aerial survey of radiation contamination they did over Gunma Prefecture, and many people are dismayed that the contamination in the prefecture looks worse than feared.

So far, the Ministry has done the aerial surveys and mapped air radiation and soil contamination in: Fukushima, Miyagi, Yamagata, Ibaraki, Tochigi, and Gunma.

From 9/27/2011 map, on air radiation (microsievert/hour, 1 meter off the ground):

Cesium-134 and -137 deposition (becquerels/square meter):

Professor Hayakawa's map that he's been updating since April (current version is 4.0):

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#Radioactive Produce: National Government Told Fukushima Farmers to Farm as Usual

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:

みんな「今年は無理だ。」って言ってたのに、国が「普通に作れ。」って言ったんです。

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:

福島市在住です。まわりの人はみんな食べません。だって農家が「今年は食えない」って言います。私は「今後は食えない」だと思っていますが

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.

To the defense of Fukushima farmers, I am aware that there are many who stopped farming after the accident, and stopped selling their produce because they do not want to force potentially contaminated food on the consumers.

Another "un-confirmable" evidence of the national government's culpability is one particular tweet from March which I cannot locate any more but I remember very vividly. It was from someone whose family was the rice farmer in Niigata Prefecture. The JA (agricultural producer co-op) in the area held a meeting and decided to increase the area for planting rice because they thought the rice production in Fukushima would be significantly reduced because of the nuclear accident. To that request, the national government (Ministry of Agriculture, Forestry and Fisheries) answered not to bother, and told them to reduce the area for planting rice as scheduled.

Extend and pretend. The national government wanted to pretend to the farmers, to the citizens of Japan and to the outside world that everything was normal, and insisted the farmers in Fukushima till the land and plant just like last year, and the rice farmers in Niigata to reduce their crop as agreed last year. Many Fukushima farmers, even though their good senses told them that might be a bad idea, went along for whatever reason, tilled the land and planted.

No doubt they were soothed by the comforting message from Dr. Shunichi Yamashita, who was all over Fukushima preaching it was safe and everything was OK.

As the result, radioactive cesium, plutonium, cobalt, and whatever else fell on top of the soil were turned over with the soil and buried deeper and mixed with clean soil.

And this national government under the new administration continues to say it will be responsible for decontamination. It is as if they wanted the soil contamination to go deeper so that the decontamination would be on a much, much bigger scale than otherwise, creating bigger and costlier projects for the well-connected companies and individuals.

The minister who will be in charge of decontamination and other massive cleanup efforts says we have to share the pain of Fukushima, even as the pain was partly caused and made worse by his government to begin with.

I suppose they could justify the astronomical scale of decontamination by saying "it will create jobs in the area", which is exactly what they said when they promoted nuclear power plants in rural areas of Japan in the 1960s.

Dig the ditch, bury the ditch, as long as it create jobs. Japanese Keynesians still hard at work. It's just that "ditch" is radioactive.

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Simulation Map of Cesium-137 Deposition Across the Pacific by CEREA Shows Contamination in US Greater Than That of Western Japan

France's CEREA has the simulation map of ground deposition of cesium-137 from the Fukushima I Nuclear Power Plant accident on its "Fukushima" page. It not only shows Japan but also the entire northern Pacific Rim, from Russian Siberia to Alaska to the West Coast of the US to the entire US.

According to the map, the US, particularly the West Coast and particularly California, may be more contaminated with radioactive cesium than the western half of Japan or Hokkaido. It looks more contaminated than South Korea or China. Canada doesn't look too well either, particularly along the border with US on the western half.

From CEREA's Fukushima page:

Atmospheric dispersion of radionuclides from the Fukushima-Daichii nuclear power plant

CEREA, joint laboratory École des Ponts ParisTech and EdF R&D
Victor Winiarek, Marc Bocquet, Yelva Roustan, Camille Birman, Pierre Tran

Map of ground deposition of caesium-137 for the Fukushima-Daichii accident.

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisations used for the transport and physical removal of the radionuclides are described in [1,2,3,4].

The magnitude of the deposition field is uncertain and the simulated values of deposited radionuclides could be significantly different from the actual deposition. In particular, the source term remains uncertain. Therefore, these results should be seen as preliminary and they are likely to be revised as new information become available to better constrain the source term and when radionuclides data can be used to evaluate the model simulation results.

The page also has the animated simulation of cesium-137 dispersion from March 11 to April 6, 2011. If the Japanese think they are the only ones who have the radiation and radioactive fallout from the accident, they are very much mistaken, if the simulation is accurate. (Meteorological institutes and bureaus in Austria, Germany, and Norway all had similar simulation maps.)

Radioactive materials spewed out of Fukushima I Nuke Plant went up and away on the jet stream, reaching the other side of the Pacific. When the fallout from explosions (March 14, 15) reached the US West Coast, it came with an unusually heavy rainfall in California.

CEREA's description of the animation (if the animation doesn't work, or if you want to see the bigger one, go to CEREA's page):

Movie of the Fukushima-Daichii activity in the air (caesium-137, ground level)

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisations used for the transport and physical removal of the radionuclides are described in [1,2,3,4].

The magnitude of activity concentration field is uncertain and could be significantly different from the actual one. In particular, the source term remains uncertain. Therefore, these results should be seen as preliminary and they are likely to be revised as new information become available to better constrain the source term and when radionuclides data can be used to evaluate the model simulation results.

(Go to their page to see the references.)

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Soil Contamination in 34 Locations in Fukushima Exceeds Chernobyl Confiscation/Closed Zone Level

In one location, the contamination level is more than 10 times the Chernobyl level.

What a surprise. Now that PM Kan is out, the government dribbles out the information that it withheld as it de-emphasized and even attacked the reports of high soil contamination as measured by private entities including citizens' groups.

The most contaminated location found so far is Okuma-machi, where Fukushima I Nuke Plant is located: 29,460,000 becquerels per square meter with cesium-134 and cesium-137 combined, 15,450,000 becquerels per square meter if only cesium-137 is counted.

The confiscated/closed zone after the Chernobyl accident is set in locations whose cesium-137 level in soil exceeds 1,480,000 becquerels per square meter. The level of cesium-137 in the location in Okuma-machi is 10 times that of the Chernobyl confiscated/closed zone.

From Yomiuri Shinbun (3:05AM JST 8/30/2011):

東京電力福島第一原子力発電所事故で拡散した放射性物質による土壌汚染の状態を調べた地図がまとまり、２９日に開かれた文部科学省の検討会で報告された。

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.

　立ち入りが制限されている警戒区域や計画的避難区域で、チェルノブイリ原発事故での強制移住基準（１平方メートル当たりの放射性セシウム１３７が１４８万ベクレル）を超える汚染濃度が測定されたのは、６市町村３４地点に上った。住民の被曝(ひばく)線量などを把握するのが狙い。菅首相が２７日、「長期間にわたり住民の居住が困難になる地域が生じる」との見通しを示したが、それを裏付けた。

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.

　測定結果によると、６月１４日時点で、セシウム１３７の濃度が最も高かったのは、警戒区域内にある福島県大熊町の１平方メートル当たり約１５４５万ベクレル。セシウム１３４と合わせると、同約２９４６万ベクレルとなった。

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.

　同３００万ベクレル超となったのは、セシウム１３７で同町、双葉町、浪江町、富岡町の計１６地点に上った。高い濃度の地点は、原発から北西方向に延びており、チェルノブイリ事故の強制移住基準を超える地点があった自治体は、飯舘村、南相馬市を加えた計６市町村だった。同省は約２２００地点の土壌を測定した。

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.

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