Specific activity and activity ratios of radionuclides in soil collected about 20 km from the Fukushima Daiichi Nuclear Power Plant: Radionuclide release to the south and southwest

doi:10.1016/j.scitotenv.2011.07.067

Science of The Total Environment

Volume 409, Issue 22, 15 October 2011, Pages 4885-4888

https://doi.org/10.1016/j.scitotenv.2011.07.067 Get rights and content

Abstract

Soil samples at different depths (0–2, 5–7 and 10–12 cm) were collected from J Village, about 20 km south of Fukushima Daiichi Nuclear Power Plant (FNPP) to determine their radionuclide specific activities and activity ratios. The concentrations and activity ratios of ¹³¹I, ^{134, 136, 137}Cs and ^129mTe were obtained, but only trace amounts of ⁹⁵Nb, ^110mAg and ¹⁴⁰La were detected which were too low to provide accurate concentrations. Radionuclides such as ⁹⁵Zr, ^{103, 106}Ru and ¹⁴⁰Ba that were found in Chernobyl fallout, were not found in these soil samples. This suggests that noble gasses and volatile radionuclides predominated in the releases from FNPP to the terrestrial environment. The average activity ratios of ¹³¹I/¹³⁷Cs, ¹³⁴Cs/¹³⁷Cs, ¹³⁶Cs/¹³⁷Cs and ^129mTe/¹³⁷Cs were 55, 0.90, 0.22 and 4.0 (corrected to March 11, 2011) in the 0–2 cm soil samples of April 20 and 28, 2011.

Highlights

► Soil samples were collected at about 20 km south of Fukushima Daiichi Nuclear Power Plant. ► The concentrations of ¹³¹I, ^{134, 136, 137}Cs and ^129mTe were obtained, but ¹⁰³Ru was not. ► This suggests that noble gasses and volatile radionuclides predominated in the releases. ► Activity ratio of ¹³⁴Cs/¹³⁷Cs from the power plant to the south was abound 0.90.

Introduction

The Fukushima Daiichi Nuclear Power Plant (FNPP) lost all electricity due to a huge tsunami after the Richter-scale magnitude 9 earthquake of March 11, 2011. The water circulation systems of Units 1, 2 and 3 were severely damaged, and radionuclides were released to the environment, especially for days in the middle of March. Concentrations of the radionuclides released was not clearly known at the time these early releases; thus deposition samples were collected at National Institute of Radiological Sciences (NIRS) in Chiba City, which is located about 220 km from FNPP and radionuclides such as ¹³²Te (decays to ¹³²I), ¹³¹I, ¹³⁴Cs, ¹³⁷Cs and ¹³⁶Cs were found (Tagami et al., 2011).

The released radionuclides have already been deposited on land and sea surfaces. Recently, environmental radioactivity levels in the Kanto Plain which includes Tokyo and is located south and southwest from FNPP, have become of growing concern to the public. Since ¹³⁷Cs has a long half-life of 30.04 y and it is relatively easy to detect, its specific activity data will be used for the dose estimation in the future. However, it is necessary to obtain more data on the activity ratios of short-lived radionuclides to ¹³⁷Cs to estimate the total dose from radionuclides released from FNPP. In this study, to measure major radionuclides released to the south and southwest from FNPP, soil sampling was conducted in J Village, located about 20 km south of FNPP on April 20, 28 and May 4, 2011.

Section snippets

Materials and methods

Soil samples, at 0–2, 5–7 and 10–12 cm depths, were collected from a flower garden of J Village on April 20, 28 and May 4, 2011. At each sampling time, one soil core sample (about 30 cm wide area) was collected using a scoop and a ruler to check depths. The hole made using the scoop was a conic form and each sample layer were collected, and soils between 2–5 and 7–10 cm depths were removed to avoid any contamination to lower layers. The second and the third collection were carried out at 2 m

Results and discussion

Fig. 1 shows gamma-ray spectra of soil samples collected before (collected in 2003 from an agricultural field in Fukushima Prefecture) and after the accident (a 0–2 cm sample from J Village, collected on April 20, 2011). Only a small peak of ¹³⁷Cs from global fallout was observed in the soil collected before the accident with 80,000 s counting time (Fig. 1(A)), but many peaks from artificial radionuclides were observed after the accident with a shorter counting time of 3600 s (Fig. 1(B)). From

Conclusion

Specific radioactivities and activity ratios were determined in soil samples collected about 20 km south of FNPP. The measured activity ratio of ¹³⁴Cs/¹³⁷Cs was 0.9, which was higher than that observed in Chernobyl fallout. The measured activity ratios of ¹³⁴Cs/¹³⁷Cs were almost the same in the south and southwest areas. However, other directions would be unlikely to have the same activity ratios because of different stages in a complex series of releases and wind directions. This work offers an

Acknowledgments

The authors thank Dr. E. R. Landa (U.S. Geological Survey) and Dr. C. Kikuchi (MCK Consulting) for their valuable comments. The authors are grateful to J Village for kindly providing us with the soil samples.

References (11)

L. Monte
Evaluation of radionuclide transfer functions from drainage basins of fresh water systems
J Environ Radioactiv
(1995)
Y. Nakamaru et al.
Role of soil organic matter in the mobility of radiocesium in agricultural soils common in Japan
Coll. Surface A
(2007)
M. Aoyama et al.
Deposition of gamma-emitting nuclides in Japan after the reactor-IV accident at Chernobyl
J Radioanal Nucl Chem
(1987)
International Atomic Energy Agency
Present and future environmental impact of the Chernobyl accident. IAEA-TECDOC-1240
(2001)
International Atomic Energy Agency
Handbook of parameter values for the prediction of radionuclide transfer in terrestrial and freshwater environments. IAEA-TRS-472
(2010)

There are more references available in the full text version of this article.

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Science of The Total Environment

Abstract

Highlights

Introduction

Section snippets

Materials and methods

Results and discussion

Conclusion

Acknowledgments

References (11)

Evaluation of radionuclide transfer functions from drainage basins of fresh water systems

J Environ Radioactiv

Role of soil organic matter in the mobility of radiocesium in agricultural soils common in Japan

Coll. Surface A

Deposition of gamma-emitting nuclides in Japan after the reactor-IV accident at Chernobyl

J Radioanal Nucl Chem

Present and future environmental impact of the Chernobyl accident. IAEA-TECDOC-1240

Handbook of parameter values for the prediction of radionuclide transfer in terrestrial and freshwater environments. IAEA-TRS-472

Cited by (90)

Development of a potassium-based soil washing solution using response surface methodology for efficient removal of cesium contamination in soil

Radioactivity concentration measurements in fish and shellfish samples from the west coast of Canada after the Fukushima nuclear accident (2011–2018)

Gamma-irradiation fluctuates the mRNA N<sup>6</sup>-methyladenosine (m<sup>6</sup>A) spectrum of bone marrow in hematopoietic injury

Response surface modeling with Box-Behnken design for strontium removal from soil by calcium-based solution

Fukushima Accident: 10 Years After

Processes affecting land-surface dynamics of <sup>129</sup>I impacted by atmospheric <sup>129</sup>I releases from a spent nuclear fuel reprocessing plant

Short CommunicationSpecific activity and activity ratios of radionuclides in soil collected about 20 km from the Fukushima Daiichi Nuclear Power Plant: Radionuclide release to the south and southwest

Abstract

Highlights

Introduction

Section snippets

Materials and methods

Results and discussion

Conclusion

Acknowledgments

J Environ Radioactiv

Coll. Surface A

Deposition of gamma-emitting nuclides in Japan after the reactor-IV accident at Chernobyl

J Radioanal Nucl Chem

Present and future environmental impact of the Chernobyl accident. IAEA-TECDOC-1240

Handbook of parameter values for the prediction of radionuclide transfer in terrestrial and freshwater environments. IAEA-TRS-472

Short Communication
Specific activity and activity ratios of radionuclides in soil collected about 20 km from the Fukushima Daiichi Nuclear Power Plant: Radionuclide release to the south and southwest