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Low 134Cs/137Cs ratio anomaly in the north-northwest direction from the Fukushima Dai-ichi Nuclear Power Station

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Highlights

We present new data of 134Cs/137Cs around Fukushima Daiichi Nuclear Power Station.
The entire area of the low 134Cs/137Cs ratio anomaly around the FDNPS is revealed.
The low 134Cs/137Cs ratio anomaly is coincident with a plume trace.
The anomaly occurs in the area which had been contaminated before March 13, 2011.

Abstract

A low 134Cs/137Cs ratio anomaly in the north-northwest (NNW) direction from the Fukushima Dai-ichi Nuclear Power Station (FDNPS) is identified by a new analysis of the 134Cs/137Cs ratio dataset which we had obtained in 2011–2015 by a series of car-borne surveys that employed a germanium gamma-ray spectrometer.

We found that the 134Cs/137Cs ratio is slightly lower (0.95, decay-corrected to March 11, 2011) in an area with a length of about 15 km and a width of about 3 km in the NNW direction from the FDNPS than in other directions from the station.

Furthermore, the area of this lower 134Cs/137Cs ratio anomaly corresponds to a narrow contamination band that runs NNW from the FDNPS and it is nearly parallel with the major and heaviest contamination band in the west-northwest.

The plume trace with a low 134Cs/137Cs ratio previously found by other researchers within the 3-km radius of the FDNPS is in a part of the area with the lower 134Cs/137Cs ratio anomaly that we found.

Our result suggests that this lower 134Cs/137Cs ratio anomaly is the area which was contaminated before March 13, 2011 (UTC) in association with the hydrogen explosion of Unit 1 on March 12, 2011 at 06:36 (UTC) and it was less influenced by later subsequent plumes.

http://www.sciencedirect.com/science/article/pii/S0265931X17301947

 

September 20, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

Oceanic dispersion of Fukushima-derived radioactive cesium: a review

This paper focuses on the radioactive Cs in seawater and summarizes estimates of the total amount of released radioactive Cs from the FNPP site, spatio–temporal changes in the concentrations of 134Cs and 137Cs not only off the coast of Fukushima and adjacent prefectures, but also in the North Pacific, and adjacent seas such as Japan Sea, East China Sea, based on measurement results and simulation models published during 4 years since the FNPP accident.

14 decembre 2016

Oceanic dispersion of Fukushima-derived radioactive cesium: a review

Abstract

This review summarizes the more than 70 papers published during the 4 years since the Fukushima Dai-ichi nuclear power plant accident that occurred on 11 March 2011, and details the radioactive cesium dispersion pattern in the North Pacific and adjacent seas. The total amount of Fukushima-derived radioactive cesium released into the North Pacific via atmospheric deposition and direct release, spatial and temporal changes in the Pacific coast around the accident site, and the concentration levels of radioactive cesium around the Japanese Islands, not only the Pacific coast but also in adjacent seas, such as Japan Sea, East China Sea are summarized. Based on observational data mostly obtained during 2 years since the accident, and simulation results, oceanic dispersion of radioactive cesium in the entire area of the North Pacific is described. The Fukushima-derived radioactive cesium dispersed eastward as surface water and extended to the eastern side of the North Pacific in 2014, and was also observed via a southward intrusion to subsurface waters as Subtropical Mode Water and Central Mode Water. The radioactive cesium movement related to mode water is important in terms of the circulation of cesium into the ocean interior. Some new technologies and techniques concerning emergency monitoring of radioactivity in the ocean environment are also reported, the effectiveness of which has been demonstrated by use in relation to the Fukushima accident.

Introduction

On 11 March 2011, the Great East Japan Earthquake (Mw 9.0) occurred at the plate boundary off the coast of Tohoku, northeastern Japan. A huge tsunami was generated and caused 15 729 fatalities and 4539 missing in the Hokkaido, Tohoku and Kanto regions (The National Police Agency, as of 24 August 2011). Preliminary surveys reported tsunami waves with run-up heights exceeding 30 m (Mori et al., 2011). The tsunami also hit the Fukushima Dai-ichi Nuclear Power Plant (FNPP) sites located at 37˚25’N, 141˚02’E, and a loss of electric power at FNPP resulted in overheated reactors and hydrogen explosions. Radioactive materials were then released into the ocean through atmospheric fallout (such as aerosols and precipitation) and as direct releases (controlled releases related to safety issues at FNPP) as well as uncontrolled leaking of the heavily contaminated coolant water (Buesseler et al., 2011; Chino et al., 2011; Takemura et al., 2011). This accidental release of anthropogenic radionuclides (mostly iodine-131, cesium-134 and -137; 131I, 134Cs and 137Cs) resulted in severe elevations of these radionuclides in fisheries products in the coastal areas of Fukushima and adjacent prefectures (Buesseler, 2012; Yoshida and Kanda, 2012; Wada et al., 2013; Nakata and Sugisaki, 2015). Owing to its relatively long half-life (2.07 years for 134Cs and 30.07 years for 137Cs), the evaluation of these radioactive Cs isotopes in the marine environment is important for addressing risks to both marine ecosystems and public health through consumption of fisheries products. Generally, cesium is a conservative element and mostly occurs in the dissolved phase in the marine environment. The concentration of radioactive cesium in marine organisms is strongly affected by its concentration in the surrounding seawater. Actually, temporal changes in radioactive Cs concentrations of many pelagic fish species in the near coastal area off Fukushima and adjacent prefectures were associated with those in seawater after the FNPP accident (e.g., Wada et al., 2013; Takagi et al., 2015; Morita et al., unpublished data). Kaeriyama et al. (2015) and Morita et al. unpublished data revealed the time-lagged temporal changes in radioactive Cs in organisms (zooplankton and Pacific saury) and seawater under non-steady-state conditions after the FNPP accident, and showed that the concentration ratios in these organisms had been elevated when compared with those before the FNPP accident. With regard to zooplankton, Baumann et al. (2015) discussed the possible uptake of Fukushima-derived radioactive Cs from phytoplankton dominated suspended particles. As a consequence, radioactive Cs would be transferred to the higher trophic level not only via surrounding seawater but also by prey-predator interactions in the pelagic ecosystem. Shigenobu et al. (2014) reported the radioactive Cs concentrations of fat greenling (Hexagrammos otakii) caught off the coast of Fukushima Prefecture, and reported two outlier specimens caught in August 2012 and May 2013 which had ambiguously high 137Cs concentrations of more than 1000 Bq/kg-wet. Probability analysis indicated that the two outlier fat greenlings had migrated from the port of FNPP. In the port of FNPP, extremely high 137Cs concentrations were reported from Japanese rockfish (Sebastes cheni), brown hakeling (Physiculus maximowiczi) and fat greenling (H. otakii) caught during January and February 2013 (Fujimoto et al., 2015). The maximum concentration of 137Cs (129 kBq/kg-wet) was detected from fat greenlings. Wada et al. (2013) with the corrigendum (Wada et al., 2014) summarized the monitoring results of radioactive Cs concentrations in fisheries products from Fukushima Prefecture and revealed time-series trends. Clear trends include a slower decrease of radioactive Cs in demersal fish compared to pelagic fish as well as spatial heterogeneity; specimens sampled in the area south of FNPP tended to have higher concentrations of radioactive Cs than those caught in the area north of FNPP. Sohtome et al. (2014) reported the time-course trends in concentration of radioactive Cs in invertebrates in the coastal benthic food web near the FNPP. The difference in decreasing trends observed within the organisms and the concentrations of radioactive Cs in some of the sea urchins (Echinocardium cordatum and Glyptocidaris crenularis) were clearly affected by the contaminated sediments taken into their digestive tract.

This paper focuses on the radioactive Cs in seawater and summarizes estimates of the total amount of released radioactive Cs from the FNPP site, spatio–temporal changes in the concentrations of 134Cs and 137Cs not only off the coast of Fukushima and adjacent prefectures, but also in the North Pacific, and adjacent seas such as Japan Sea, East China Sea, based on measurement results and simulation models published during 4 years since the FNPP accident.

Total Amount of FNPP–Released Radioactive Cesium

Information on the total amount of the FNPP-released radioactive Cs into the North Pacific is critical information to enable effective monitoring and resource management. However, despite its importance, estimation of atmospheric deposition is complex due to lack of the observational data in the oceanic environment. The activity ratios of 134Cs/137Cs, decay corrected to March–April 2011, were reported to be almost 1.0 for the entire North Pacific (e.g., Buesseler et al., 2011, 2012; Kaeriyama et al., 2014). This ratio means an equivalent amount of 134Cs and 137Cs was released into the ocean. Under the limitation of data concerning not only the amount of radioactive Cs in aerosols but also on precipitation in the North Pacific, estimation of atmospheric deposition remains a source of considerable uncertainty (5–15 PBq of 134Cs and 137Cs; 1 PBq = 1015 Bq, Table 1). In contrast, the direct release of radioactive Cs (134Cs and 137Cs) into the ocean as uncontrolled leaking of the heavily contaminated coolant water is well estimated as approximating the value of 3.5 PBq, with the exception of Bailly du Bois et al. (2012) and Charette et al. (2013) (Table 1). Dietze and Kriest (2012) discussed the possible overestimates by Bailly du Bois et al. (2012) as a result of methodological issues. Charette et al. (2013) estimated the direct release inventory from the observational data of radioactive Cs with radium isotopes in May–June 2011, and no atmospheric deposition was assumed. Their estimates of direct releases may be included in the atmospheric deposition. Tsumune et al. (2012) clearly showed that direct releases started on 26 March 2011 using 131I/137Cs activity ratios, which varied much more before 26 March 2011 when the atmospheric deposition was the major source. The most recent estimations have revealed that 3–4 PBq of 134Cs and 137Cs were directly released into the ocean and 12–15 PBq of 134Cs and 137Cs were deposited on the surface seawater in the North Pacific (Aoyama et al., 2015a).

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Table 1. Estimated total inventory of 137Cs (PBq) in the North Pacific in 2011

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Figure 1.

Schematic view of current system: (a) in the North Pacific and (b) around the Japanese Islands. Solid lines indicate surface current and dashed lines indicate the movement of mode waters. FNPP: Fukushima Dai-ichi Nuclear Power Plant; STMW: Subtropical Mode Water; CMW: Central Mode Water. Based on Kumamoto et al. (2014); Oka et al. (2011, 2015); Talley (1993) and Yasuda (2003) [Colour figure can be viewed at wileyonlinelibrary.com].

 

Read more : http://onlinelibrary.wiley.com/doi/10.1111/fog.12177/full

 

March 28, 2017 Posted by | Fukushima 2017 | , , , | Leave a comment

Both Cesium 134 and 137 in Potato Chips

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The ongoing Fukushima radiation contaminating the populace in Japan and abroad is still going unabated. Cleverly, authorities have succeeded in numbing millions of people to the danger of radiation from the Fukushima crisis.

Whether you are continously inhaling it (as they are incenarating radioactive waste under everyone noses for years now) or you are being dosed off in Cs 137 with some rains or snow, the most dangerous ways remains eating contaminated food. Even potato chips!

Kampu, a citizen food testing group found both cesium 134 and 137 in a potato chips bag. The chips were harvested and manufactured in 2015 with the potatoes coming from Ibaraki and Chiba prefectures. Both prefectures not included by the government in the areas having agriculture with risk of contamination.
The potato chip brand, Calbee is being sold in Japan and also globally including to the US. Calbee has a manufacturing plant in the US, so to determine what factory made a product may be a wise precaution.

So while the media prostitute and this lying led government is trying to tell everyone all Is ok, just know contaminated produces (at safe levels they will tell you ? when being caught) is openly being fed to you in restaurants (usually big chains in Japan thx Yoshinoya), convenience stores and super markets. It is also being sold all around the world.

Please note that these potato chips were harvested in Ibaraki and Chiba. .. not Fukushima. They are trying to tell you the contamination is limited to a few km away from the destroyed Nuclear Power Plant. It’s a damn lie and you should know better.

Anyway; Bon appetit!

http://beguredenega.com/archives/11931

December 23, 2016 Posted by | Fukushima 2016 | , , | Leave a comment

Fukushima radiation has reached U.S. shores

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Tanks holding radiation contaminated water at the Tokyo Electric Power Co.’s embattled Fukushima Daiichi nuclear power plant on February 25, 2016 in Okuma, Japan.

Its official. Woods Hole Oceanographic Institute has samples of Fukushima-sourced cesium-134 in salmon off the Pacific Coast of Oregon. Given cesium-134 has such a short half-life the source is linked to the on-going leaks from Japan’s 2011 nuclear disaster. While the amount is still very, very low, it remains a concern given the Fukushima disaster is still not contained after more than five years.

SALEM, Ore. — For the first time, seaborne radiation from Japan’s Fukushima nuclear disaster has been detected on the West Coast of the United States.

Cesium-134, the so-called fingerprint of Fukushima, was measured in seawater samples taken from Tillamook Bay and Gold Beach in Oregon, according to researchers from the Woods Hole Oceanographic Institution.

Because of its short half-life, cesium-134 can only have come from Fukushima.

For the first time, cesium-134 has also been detected in a Canadian salmon, according to the Fukushima InFORM project, led by University of Victoria chemical oceanographer Jay Cullen.

Should we be worried? In both cases, levels are extremely low, the researchers said, and don’t pose a danger to humans or the environment.

Massive amounts of contaminated water were released from the crippled nuclear plant following a 9.0 magnitude earthquake and tsunami in March 2011. More radiation was released to the air, then fell to the sea.

Woods Hole chemical oceanographer Ken Buesseler runs a crowd-funded, citizen science seawater sampling project that has tracked the radiation plume as it slowly makes its way across the Pacific Ocean.

The Oregon samples, marking the first time cesium-134 has been detected on U.S. shores, were taken in January and February of 2016 and later analyzed. They each measured 0.3 becquerels per cubic meter of cesium-134.

Buesseler’s team previously had found the isotope in a sample of seawater taken from a dock on Vancouver Island, B.C., marking its landfall in North America.

In Canada, Cullen leads the InFORM project to assess radiological risks to that country’s oceans following the nuclear disaster. It is a partnership of a dozen academic, government and non-profit organizations.

Last month, the group reported that a single sockeye salmon, sampled from Okanagan Lake in the summer of 2015, had tested positive for cesium-134.

The level was more than 1,000 times lower than the action level set by Health Canada, and is no significant risk to consumers, Cullen said.

Buesseler’s most recent samples off the West Coast also are showing higher-than background levels of cesium-137, another Fukushima isotope that already is present in the world’s oceans because of nuclear testing in the 1950s and 1960s.

Those results will become more important in tracking the radiation plume, Buesseler said, because the short half-life of cesium-134 makes it harder to detect as time goes on.

Cesium-134 has a half-life of two years, meaning it’s down to a fraction of what it was five years ago, he said. Cesium-137 has a 30-year half-life.

A recent InFORM analysis of Buesseler’s data concluded that concentrations of cesium-137 have increased considerably in the central northeast Pacific, although they still are at levels that pose no concern.

It appears that the plume has spread throughout this vast area from Alaska to California,” the scientists wrote.

They estimated that the plume is moving toward the coast at roughly twice the speed of a garden snail. Radiation levels have not yet peaked.

As the contamination plume progresses towards our coast we expect levels closer to shore to increase over the coming year,” Cullen said.

Even that peak won’t be a health concern, Buesseler said. But the models will help scientists model ocean currents in the future.

That could prove important if there is another disaster or accident at the Fukushima plant, which houses more than a thousand huge steel tanks of contaminated water and where hundreds of tons of molten fuel remain inside the reactors.

In a worst-case scenario, the fuel would melt through steel-reinforced concrete containment vessels into the ground, uncontrollably spreading radiation into the surrounding soil and groundwater and eventually into the sea.

That’s the type of thing where people are still concerned, as am I, about what could happen,” Buesseler said.

Scientists now know it would take four to five years for any further contamination from the plant to reach the West Coast.

Tracking the plume

Scientists are beginning to use an increase in cesium-137 instead of the presence of cesium-134 to track the plume of radioactive contamination from Japan’s Fukushima nuclear disaster. These figures show the increase in cesium-137 near the West Coast between 2014 and 2015.

Graphic courtesy Dr. Jonathan Kellogg of InFORM, with data from Dr. John Smith, Department of Fisheries and Oceans Canada, and Dr. Ken Buesseler, Woods Hole Oceanographic Institute.

http://www.msn.com/en-us/news/us/fukushima-radiation-has-reached-us-shores/ar-AAlkXUr?li=BBmkt5R&ocid=spartandhp

 

 

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December 19, 2016 Posted by | Fukushima 2016 | , , , , | Leave a comment

Fukushima radiation has reached U.S. shores

Its official. Woods Hole Oceanographic Institute has samples of Fukushima-sourced cesium-134 in salmon off the Pacific Coast of Oregon. Given cesium-134 has such a short half-life the source is linked to the on-going leaks from Japan’s 2011 nuclear disaster. While the amount is still very, very low, it remains a concern given the Fukushima disaster is still not contained after more than five years.
SALEM, Ore. — For the first time, seaborne radiation from Japan’s Fukushima nuclear disaster has been detected on the West Coast of the United States.
Cesium-134, the so-called fingerprint of Fukushima, was measured in seawater samples taken from Tillamook Bay and Gold Beach in Oregon, according to researchers from the Woods Hole Oceanographic Institution.
Because of its short half-life, cesium-134 can only have come from Fukushima.
For the first time, cesium-134 has also been detected in a Canadian salmon, according to the Fukushima InFORM project, led by University of Victoria chemical oceanographer Jay Cullen.
Should we be worried? In both cases, levels are extremely low, the researchers said, and don’t pose a danger to humans or the environment. Massive amounts of contaminated water were released from the crippled nuclear plant following a 9.0 magnitude earthquake and tsunami in March 2011. More radiation was released to the air, then fell to the sea.
Woods Hole chemical oceanographer Ken Buesseler runs a crowd-funded, citizen science seawater sampling project that has tracked the radiation plume as it slowly makes its way across the Pacific Ocean.
The Oregon samples, marking the first time cesium-134 has been detected on U.S. shores, were taken in January and February of 2016 and later analyzed. They each measured 0.3 becquerels per cubic meter of cesium-134.
Buesseler’s team previously had found the isotope in a sample of seawater taken from a dock on Vancouver Island, B.C., marking its landfall in North America.
In Canada, Cullen leads the InFORM project to assess radiological risks to that country’s oceans following the nuclear disaster. It is a partnership of a dozen academic, government and non-profit organizations.
Last month, the group reported that a single sockeye salmon, sampled from Okanagan Lake in the summer of 2015, had tested positive for cesium-134.
The level was more than 1,000 times lower than the action level set by Health Canada, and is no significant risk to consumers, Cullen said.
Buesseler’s most recent samples off the West Coast also are showing higher-than background levels of cesium-137, another Fukushima isotope that already is present in the world’s oceans because of nuclear testing in the 1950s and 1960s.
Those results will become more important in tracking the radiation plume, Buesseler said, because the short half-life of cesium-134 makes it harder to detect as time goes on.
Cesium-134 has a half-life of two years, meaning it’s down to a fraction of what it was five years ago, he said. Cesium-137 has a 30-year half-life.
A recent InFORM analysis of Buesseler’s data concluded that concentrations of cesium-137 have increased considerably in the central northeast Pacific, although they still are at levels that pose no concern.
“It appears that the plume has spread throughout this vast area from Alaska to California,” the scientists wrote.
They estimated that the plume is moving toward the coast at roughly twice the speed of a garden snail. Radiation levels have not yet peaked.
“As the contamination plume progresses towards our coast we expect levels closer to shore to increase over the coming year,” Cullen said.
Even that peak won’t be a health concern, Buesseler said. But the models will help scientists model ocean currents in the future.
That could prove important if there is another disaster or accident at the Fukushima plant, which houses more than a thousand huge steel tanks of contaminated water and where hundreds of tons of molten fuel remain inside the reactors.
In a worst-case scenario, the fuel would melt through steel-reinforced concrete containment vessels into the ground, uncontrollably spreading radiation into the surrounding soil and groundwater and eventually into the sea.
“That’s the type of thing where people are still concerned, as am I, about what could happen,” Buesseler said.
Scientists now know it would take four to five years for any further contamination from the plant to reach the West Coast.
Tracking the plume
Scientists are beginning to use an increase in cesium-137 instead of the presence of cesium-134 to track the plume of radioactive contamination from Japan’s Fukushima nuclear disaster. These figures show the increase in cesium-137 near the West Coast between 2014 and 2015.
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137 Cesium Activity in 2014. (Photo: Dr. Jonathan Kellogg / InFORM)
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137 Cesium Activity in 2015. (Photo: Dr. Jonathan Kellogg / InFORM)
Graphic courtesy Dr. Jonathan Kellogg of InFORM, with data from Dr. John Smith, Department of Fisheries and Oceans Canada, and Dr. Ken Buesseler, Woods Hole Oceanographic Institute.

December 9, 2016 Posted by | Fukushima 2016 | , , , , , | Leave a comment

Eastern Japan Soil Becquerel Measurement Project Map

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Iwaki City

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Tomioka

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Naraha

Source Minna no Data website:

http://www.minnanods.net/maps/zoommap/

October 5, 2016 Posted by | Fukushima 2016 | , , , , | Leave a comment

Radioactive cesium (134Cs and 137Cs) content in human placenta after the Fukushima nuclear power plant accident

First published: 2 July 2013

Abstract

Aim

The degree of contamination with radioactive cesium (134Cs and 137Cs) in the human placenta after the accident at Fukushima nuclear power plant (FNP), which occurred on 11 March 2011, has not been assessed.

Material and Methods

134Cs and 137Cs contents were determined in 10 placentas from 10 women who gave birth to term singleton infants during the period between October 2011 and August 2012 using high-purity germanium detectors for gamma ray spectrometry. Five women resided within 50 km of FNP (neighbor group) and gave birth by the end of February 2012, while the other five women resided within 210–290 km of FNP (distant group) and gave birth in July and August 2012.

Results

All except one of the 10 placentas contained detectable levels of 134Cs and 137Cs, ranging 0.042–0.742 Bq/kg for 134Cs and 0.078–0.922 Bq/kg for 137Cs. One placenta from a woman living in Tokyo contained 0.109 Bq/kg 137Cs and no detectable level of 134Cs (<0.054 Bq/kg). 137Cs content was more than 0.2 Bq/kg in four and one placentas in the neighbor and distant groups, respectively.

Conclusion

Degree of contamination of the placenta with radioactive Cs was lower even in women who resided within 50 km of FNP compared to Japanese and Canadian placentas in the mid-1960s after repeated nuclear tests and in northern Italian placentas from 1986–1987 after the Chernobyl power plant accident.

Introduction

After the accident at Fukushima nuclear power plant (FNP), triggered by the Great East Japan Earthquake on 11 March 2011, radioactive fallout was deposited over a wide area of Japan.[1, 2] Although the short-lived radionuclides, such as 131I (half-life, 8 days), decayed within a few days to months eventually reaching negligible concentrations, long-lived radioactive cesium (physical half-life, 2 years for 134Cs and 30 years for 137Cs) remained in detectable concentrations in the environment. These radionuclides reach pregnant women mainly through direct consumption of contaminated vegetables, crops, as well as animal and fish products. Contamination of breast milk with 131I was indeed documented in lactating women residing near FNP in April 2011.[1] The occurrence of milk powder contamination with 134Cs and 137Cs (22–31 Bq/kg) was announced by Meiji Holdings on 6 December 2011 (cited on 6 August 2012; available from http://www.meiji.co.jp/notice/2011/detail/20111206.html). This contamination was concluded to be derived from atmospheric air during the process of drying of milk powder, and not from water or dairy ingredients. Thus, environmental pollution with radioactive materials occurred and reached pregnant women after the FNP accident.

The placentas of women living in Hiroshima, Osaka, Tokyo and Canada in the 1960s contained detectable levels of 137Cs[3-5] due to environmental pollution with 137Cs after the repeated nuclear tests conducted by several countries, such as the USA and the former USSR. As the estimate of 137Cs deposition at the Meteorological Research Institute, Tsukuba, after the FNP accident far exceeded that in the 1960s in Japan (Fig. 1),[6] the placentas of women living near FNP may contain higher levels of 134Cs and 137Cs than those in the 1960s in Japan. However, the degree of placental contamination with radioactive Cs has not been studied. Therefore, the present study was performed to investigate the 134Cs and 137Cs contents in the placentas of women living within 300 km of FNP.

1

Figure 1.

Estimates of 137Cs deposition at the Meteorological Research Institute, Tsukuba, are presented for several months after the accident in March 2011. The estimate was computed based on the value obtained by measuring aliquots of the sample water (wet + dry depositions). As cesium is distributed between the liquid and the solid phases, the accurate value is not obtained unless the concentration of the whole sample by evaporation is achieved. Probably, current values are underestimates. Moreover, as 134Cs was deposited in comparable amounts, the total radioactive cesium had mostly doubled. image, 137Cs; image, 90Sr. (Adopted from [6]).

Materials and Methods

This study was conducted with the approval of the institutional review boards of Kameda General Hospital and Japan National Institute of Public Health.

Women who provided placentas

Placentas were obtained from 10 women: five (cases 1–5) living within 50 km (neighbor group) and five (cases 6–10) living within 210–290 km (distant group) of FNP until delivery after the FNP accident (Table 1). All 10 women gave birth to a healthy term singleton infant during the period between October 2011 and August 2012. The five women in the neighbor group gave birth earlier by the end of February 2012, while the five women in the distant group gave birth later in or after July 2012.

2

Measurement of radionuclides

Each whole placenta with a wet weight varying 0.418–0.672 kg was ashed to 4.13–7.40 g (Table 1) by muffle furnace at 450°C for 24 h after lyophilizing according to the preparation method recommended in the USA (http://www.epa.gov/rpdweb00/docs/marlap/402-b-04-001b-12-final.pdf). These ashed samples were placed individually into cylindrical plastic containers (100-mL capacity). To determine the gamma-emitting nuclides in the samples, gamma ray spectrometry was performed for more than 80 000 s with high-purity germanium detectors (GEM40-76; Ortec, Oak Ridge, TN, USA) connected to a multichannel analyzer and analytical software, and the activity concentrations of the radionuclides were corrected to the delivery dates. Each measured radioactivity was multiplied by 2(N/T): N and T were intervals until the measurement after delivery of the placenta (year) and half-life of each radionuclide (year), respectively. The energy and efficiency calibrations were performed using the nine nuclides mixed activity standard volume sources (MX033U8; Japan Radioisotope Association, Tokyo, Japan) composed of 109Cd, 57Co, 139Ce, 51Cr, 85Sr, 137Cs, 54Mn, 88Y and 60Co. These sources, contained in the same containers as the samples, had five different heights (0.5, 1, 2, 3 and 5 cm, respectively) to determine the detection efficiency of the detector as a function of sample height.

Results

As expected, 134Cs and 137Cs were detected in nine and 10 of the 10 placentas with varying activities ranging 0.042–0.742 Bq/kg for 134Cs and 0.078–0.922 Bq/kg for 137Cs, respectively (Table 1), while relatively constant levels of 40K were detected, ranging 46.5–59.3 Bq/kg, regardless of the differences in cities where they were living after the FNP accident. If we assumed that 134Cs content was 0.050 Bq/kg for case 8, median 134Cs content, 0.373 Bq/kg (range, 0.090–0.742) in the five placentas of the neighbor group was relatively higher than that of 0.061Bq/kg (range, 0.042–0.462) in the five placentas of the distant group, but difference did not reach a significant level (P = 0.05556, Mann–Whitney U-test). Median 137Cs content was 0.563 Bq/kg (range, 0.207–0.922) for the neighbor group and 0.109 Bq/kg (range, 0.078–0.694) for the distant group (P = 0.09524).

Discussion

The present study demonstrated that placentas of women living within 290 km of FNP contained detectable levels of 134Cs and 137Cs. The difference in degree of contamination of placentas with radioactive Cs may have reflected dietary habits, the degree of environmental pollution and the interval until delivery after the FNP accident. The shortened biological half-life of radioactive Cs from approximately 100 days for non-pregnant adults to approximately 60 days in pregnant women[7] may have also contributed to the lesser contamination of the placenta in women who gave birth in and after July 2012. Although environmental pollution with radioactive Cs has been decreasing, daily 137Cs activities of fallout exceeded 10 MBq/km2 in 15 days in March 2012 in Fukushima City (Preliminary results of monitoring the environmental radioactivity level of fallout [File number 93], cited on 10 August 2012; available from http://radioactivity.mext.go.jp/old/ja/1285/2012/03/1285_033018.pdf). Surface soils contained more than 1000 Bq/kg of radioactive Cs in wide areas of Fukushima Prefecture where the five women of the neighbor group were living (cited on 10 August 2012; available from http://www.s.affrc.go.jp/docs/map/pdf/02_2_04bunpu_fukushima.pdf).

As shown in Figure 1, environmental pollution with radionuclides occurred after the repeated nuclear tests in the mid-20th century and after the Chernobyl accident in 1986. According to a study that examined 137Cs content in the placenta and urine of inpatients at Hiroshima University Hospital and in daily foods served for these inpatients over a 5-year period from 1966–1970,[5] 137Cs content in the placentas was approximately 35 pCi (1.3 Bq)/kg, 137Cs daily dietary intake was approximately 30 pCi (1.1 Bq) and 137Cs daily excretion in the urine was approximately 25 pCi (0.9 Bq) in 1966. Japanese and Canadian groups investigated 137Cs content in the human placentas collected in the Tokyo and Osaka areas in Japan and in the Montreal area in Canada in the mid-1960s.[3, 4] The average content of 137Cs was similar in Japanese and Canadian placentas, regardless of the differences in dietary habits (averages of 25.2 pCi [0.93 Bq]/kg and 24.8 pCi [0.92 Bq]/kg for Japanese and Canadian placentas, respectively).[3] Thus, placentas of Japanese and Canadian women in the mid-1960s contained an average of 0.9–1.3 Bq/kg 137Cs. Placentas contained less than 0.8 Bq/kg 134Cs and less than 1.0 Bq/kg 137Cs in this study. Although there may be a problem of direct data comparison between studies in which different assay methods were used, these results suggested that placentas of Japanese and Canadian women in the mid-1960s were more heavily contaminated with 137Cs than the placentas examined in this study.

The Chernobyl accident occurred on 26 April 1986. According to the Japanese Ministry of Education, Culture, Sports, Science and Technology (released on 13 March 2012; cited on 6 August 2012; available from http://radioactivity.mext.go.jp/ja/list/338/list-1.html), total amounts of dispersed 131I and 137Cs into the environment after the FNP accident were 1.3–1.6 × 1017 Bq and 1.1–1.5 × 1016 Bq, respectively, while corresponding values after the Chernobyl accident were 1.8 × 1018 Bq and 8.5 × 1016 Bq, respectively. Thus, the degree of environmental pollution is estimated to be 11–14-fold higher for 131I and 6–8-fold higher for 137Cs after the Chernobyl accident than after the FNP accident. An Italian group examined 134Cs and 137Cs contents in the placentas of women who gave birth at the University of Bologna over a 13-month period from June 1986 to September 1987 after the Chernobyl accident.[8] Mean placental 137Cs content increased from 4.2 Bq/kg in June 1986, showing a peak of 11.5 Bq/kg in March 1987, and then decreased to 6.6 Bq/kg in September 1987.[8] The Italian group also estimated dietary 137Cs intake on the basis of the average diet in the region where study subjects lived;[8] daily 137Cs intake was estimated to be 15 Bq in the summer of 1986,[8] which is approximately 14-fold higher than that of 1.1 Bq in the Hiroshima area, Japan, in 1966.[5] An investigation conducted 4 months after the FNP accident in early July 2011 revealed that median values of daily dietary intake of 134Cs and 137Cs were 0.6 Bq and 0.9 Bq in Soma (neighboring city to the north of Minami-soma), and 0.4 Bq and 0.7 Bq in Iwaki, respectively.[9] Thus, 137Cs content per kg of the placenta well reflected daily 137Cs intake and appeared to be 50–120% of the daily 137Cs intake. Another Italian group reported daily urinary excretion of 13.5 Bq 137Cs in people living in the Pordenone area of Italy in the latter half of 1987,[10] which is more than 10-fold higher than that of 0.9 Bq in women living in the Hiroshima area in 1966.[5] Thus, levels of exposure to radioactive Cs in Japanese pregnant women in the mid-1960s and after the FNP accident were much lower than those in women living in certain areas of Europe after the Chernobyl accident. In another report from Germany,[11] the radioactive Cs load in the placenta was shown to have increased by 10-fold compared with studies before the Chernobyl accident in western Germany.

The ratio of radioactive Cs to total K (stable and radioactive) is conventionally taken as a measure of radioactive Cs contamination, independent of body size and sex.[12] Soft tissue 137Cs content corrected for potassium did not differ between mother and fetus,[13] suggesting that the placenta is not a barrier for radioactive Cs. Mean activities of placental 40K were reported to be 770 pCi per placenta (57 Bq/kg) and 45 Bq/kg in Japanese[4] and Italian[8] studies, respectively, consistent with the values ranging 46.5–59.3 Bq/kg in this study. The heaviest contaminated placenta contained 0.922 Bq/kg 137Cs and 46.5 Bq/kg 40K. This 40K activity was equivalent to a placental K level of 38.4 mmol/kg. Thus, this placenta exhibited a 137Cs to K ratio of 0.024 Bq/mmol. According to a study in Glasgow by Watson,[12] whole-body 137Cs to total body K was 0.109 Bq/mmol after the Chernobyl accident; this figure is several-fold higher than that of 0.037 Bq/mmol determined in mainland Scotland in 1978–1979,[14] and that of 0.024 Bq/mmol in the placenta of case 1 in this study. The mean whole-body activity of naturally occurring 40K was 2859 Bq for females (52 Bq/kg, if we assume that bodyweight was 55 kg),[12] falling between two figures (45 Bq/kg[8] and 57 Bq/kg[4]) of placental 40K activity. Thus, placental 40K activity concentration appeared to be similar to whole-body 40K activity concentration.

A study of the whole-body radioactive Cs[15] showed another aspect of exposure to 134Cs and 137Cs in Minami-soma residents after the FNP accident. Although only one Minami-soma resident was included in our study population, this woman showed less placental contamination than those reported in the published work.[3-5, 8] However, relatively heavy exposure to radioactive Cs occurred in residents in Minami-soma. According to a study that examined whole-body radioactive Cs (134Cs and 137Cs) in 9498 residents in Minami-soma during the period between 26 September 2011 and 31 March 2012,[15] radioactive Cs (≥210 Bq for 134Cs and ≥250 Bq for 137Cs) was detected in 38% (3051/8066) of adults and 16% (235/1432) of children (6–15 years old), ranging 210–12 771 Bq (median, 744 Bq), with a concentration of 2.3–196.5 Bq/kg (median, 11.4) for adults and 210–2953 Bq (median, 590), with a concentration of 2.8–57.9 Bq/kg (median, 11.9) for children. Based on these data, we speculated that the pregnant Minami-soma woman in this study may have managed to avoid contaminated food materials. Available data on whole-body 134Cs and 137Cs activities are as follows: whole-body 134Cs and 137Cs activities were 172 Bq and 363 Bq, respectively, in non-pregnant adults living in the Glasgow area in June and July 1986 after the Chernobyl accident;[12] and that for 137Cs activity was estimated to be 3 nCi (111 Bq) in 1966, with a gradual decline to less than 1 nCi (37 Bq) in 1969 in pregnant Japanese women living in the Hiroshima area.[5]

In conclusion, placentas from women living within 290 km of FNP contained detectable levels of 134Cs and 37Cs. However, the degree of contamination was lower than those in Japanese and Canadian women in the mid-1960s and in northern Italian women in 1986–1987 after the Chernobyl accident. It has not been elucidated how placental contamination with radioactive Cs occurring in the past affected fetuses adversely. Such adverse effects, if present, may be disclosed in follow-up studies that are being conducted in Fukushima Prefecture in future.

http://onlinelibrary.wiley.com/doi/10.1111/jog.12071/full


 

August 14, 2016 Posted by | Fukushima 2013, Fukushima 2016 | , , , | Leave a comment

Still 0.88 MBq/km2 of Cs-134/137 falls in Tokyo monthly

Still-0.88-MBqkm2-of-Cs-134137-falls-in-Tokyo-monthly-800x500_c

According to NRA (Nuclear Regulation Authority), Tokyo still has fallout from Fukushima nuclear plant.

From their report released on 8/31/2015, 0.88 MBq/km2 of Cs-134/137 falls onto Tokyo this July. The sampling location was Shinjuku.

The comparable data on Fukushima prefecture is not listed on the same report for some reason.

However the reading of Tokyo includes Cesium-134 at the significant level to prove this is from Fukushima plant.

In Miyagi prefecture, where is in the North of Fukushima prefecture, the fallout level is 0.55 MBq/km2. The fallout density in Tokyo is higher than Miyagi prefecture.

Other nuclide density is not reported.

http://radioactivity.nsr.go.jp/en/contents/11000/10193/24/195_20150831.pdf

Source: Fukushima Diary

http://fukushima-diary.com/2015/09/still-0-88-mbqkm2-of-cs-134137-falls-in-tokyo-monthly/

September 26, 2015 Posted by | Japan | , , | Leave a comment

Cs-134/137 measured from Tokyo tap-water

Cs-134137-measured-from-Tokyo-tap-water-SEPT 22, 2015

According to MHLH (Ministry of Health, Labour and Welfare), Cs-134/137 has been detected from tap-water of Tokyo since October of 2014. The data is from October 2014 to March 2015. The newer result hasn’t been announced yet.

The sample was collected from the tap of Tokyo Metropolitan Institute of Public Health in Shinjuku.

The density was from 0.00178 to 0.003 Bq/Kg. Cs-134 was detected to prove it is from Fukushima plant.

The analysis was implemented by NRA (Nuclear Regulation Authority).

All the other analyses were carried out by Tokyo Metropolitan Government Bureau of Waterworks or municipal governments and the lowest detectable amount was over 0.5 Bq/kg to show none of the actual readings.

imagebot

http://www.mhlw.go.jp/file/06-Seisakujouhou-10900000-Kenkoukyoku/0000082427.pdf
Source: Fukushima Daiichi
http://fukushima-diary.com/2015/09/cs-134137-measured-from-tokyo-tap-water/

 

September 23, 2015 Posted by | Japan | , , , , | 1 Comment

Cs-134/137 density of plant port water keeps increasing since last week

Cs-134137-density-of-plant-port-water-keeps-increasing-since-last-week-800x500_c

Cs-134/137 density reached the highest level at 2 of those 4 points mentioned above, according to Tepco. The sampling date was 9/7/2015.

These 2 points are in front of water intakes of Reactor 1 and Reactor 2. Both of them are outside of underground wall to prove high level of contamination is still leaking to the sea.

Also, Cs-134/137 density in the south of these 2 points reached the highest level. This is also outside of the underground wall, but the density went up approx. 170 % of the previous highest reading. The newly highest Cs-134/137 density was 152,000 Bq/m3.

http://www.tepco.co.jp/nu/fukushima-np/f1/smp/2015/images/2tb-east_15090801-j.pdf

Source: Fukushima Diary

http://fukushima-diary.com/2015/09/cs-134137-density-of-plant-port-water-keeps-increasing-since-last-week/

September 9, 2015 Posted by | Japan | , , , , | Leave a comment

Soil Sample July 2015 from Nakano, Tokyo — Cesium 134 Cesium 137

ThereminoMCA_2015_08_30_11_52_26-GS-for-@-Mimi

 

From  Mimi German, the head of Radcast​ in Portland, Oregon, USA:
Latest from RadCast Labs… not surprised to find Cesium134 and Cesium 137 in soil samples from Nakano, Tokyo.

Tokyo is 240 kms South of Fukushima Daiichi…
RadCast received samples of soil from Nakano, Tokyo which clearly showed both Cesium 137 and Cesium 134. This sample is from July 2015. We have 476 Bq/kg
Source: Radcast.org

https://www.radcast.org/radcast-soil-sample-july-2015-from-nakano-japan-cesium-134-cesium-137/

 

September 4, 2015 Posted by | Japan | , , , | 4 Comments

Cs-134/137 density became the highest reading at 4 points inside and outside Fukushima plant port

Cs-134137-density-became-the-highest-reading-inside-and-outside-Fukushima-plant-port-sept 1, 2015

According to Tepco, Cesium-134/137 density reached the highest reading in 3 locations of Fukushima plant port.

The samples were taken on 8/28/2015. Those sampling locations are the center of Fukushima plant port, water intake of Reactor 1 and 2, where are outside of underground wall.

In the center of Fukushima plant port, Cs-134/137 density (79,000 Bq/m3 in Cs-134/137) became as double as the previous highest reading measured at this point this July.

Additionally, Cs-137 was detected for the first time in the North of the plant, where is outside of the port. The density was 800 Bq/m3.

http://www.tepco.co.jp/nu/fukushima-np/f1/smp/2015/images/2tb-east_15082901-j.pdf

Source: Fukushima Daiichi

http://fukushima-diary.com/2015/09/cs-134137-density-became-the-highest-reading-at-4-points-inside-and-outside-fukushima-plant-port/

September 1, 2015 Posted by | Japan | , , | Leave a comment

23,900 Bq/Kg of Cs-134/137 still measured from fish in Fukushima plant port

23900-BqKg-of-Cs-134137-still-measured-from-fish-from-Fukushima-plant-port-800x500_c

Still extremely high level of Cesium-134/137 is detected from fish of Fukushima plant port from Tepco’s report released on 8/18/2015.

Cs-134/137 density was 23,900 Bq/Kg, which is 239 times much as the food safety limit.

The sample was the muscle part of Sebastes cheni collected on 7/28/2015.

Sr-90 density and other nuclides’ analysis data are not reported.

http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2015/images/fish01_150818-e.pdf

Source: Fukushima Daiichi

http://fukushima-diary.com/2015/08/23900-bqkg-of-cs-134137-still-measured-from-fish-in-fukushima-plant-port/

August 23, 2015 Posted by | Japan | , , , | Leave a comment