TY - JOUR
T1 - Novel Method of Quantifying Radioactive Cesium-Rich Microparticles (CsMPs) in the Environment from the Fukushima Daiichi Nuclear Power Plant
AU - Ikehara, Ryohei
AU - Suetake, Mizuki
AU - Komiya, Tatsuki
AU - Furuki, Genki
AU - Ochiai, Asumi
AU - Yamasaki, Shinya
AU - Bower, William R.
AU - Law, Gareth T.W.
AU - Ohnuki, Toshihiko
AU - Grambow, Bernd
AU - Ewing, Rodney C.
AU - Utsunomiya, Satoshi
N1 - Funding Information:
The authors are grateful to Dr. Watanabe for her assistance on SEM analyses at the Center of Advanced Instrumental Analysis, Kyushu University. This study is partially supported by JST Initiatives for Atomic Energy Basic and Generic Strategic Research and by a Grant-in-Aid for Scientific Research (KAKENHI) from the Japan Society for the Promotion of Science (grant nos. 16K12585, 16H04634, and JP26257402). S.U. is also supported by The Mitsubishi Foundation/Research Grants in the Natural Sciences and by ESPEC Foundation for Global Environment Research and Technology (Charitable Trust) (ESPEC Prize for the Encouragement of Environmental Studies). G.T.W.L and W.R.B acknowledge RCUK funding (grant nos. NE/M014088/1 and ST/N002474/1). The findings and conclusions of the authors of this paper do not necessarily state or reflect those of the JST.
Funding Information:
This study is partially supported by JST Initiatives for Atomic Energy Basic and Generic Strategic Research and by a Grant-in-Aid for Scientific Research (KAKENHI) from the Japan Society for the Promotion of Science (grant nos. 16K12585, 16H04634, and JP26257402). S.U. is also supported by The Mitsubishi Foundation/Research Grants in the Natural Sciences and by ESPEC Foundation for Global Environment Research and Technology (Charitable Trust) (ESPEC Prize for the Encouragement of Environmental Studies). G.T.W.L and W.R.B acknowledge RCUK funding (grant nos. NE/M014088/1 and ST/N002474/1).
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/6/5
Y1 - 2018/6/5
N2 - Highly radioactive cesium-rich microparticles (CsMPs) were released from the Fukushima Daiichi nuclear power plant (FDNPP) to the surrounding environment at an early stage of the nuclear disaster in March of 2011; however, the quantity of released CsMPs remains undetermined. Here, we report a novel method to quantify the number of CsMPs in surface soils at or around Fukushima and the fraction of radioactivity they contribute, which we call "quantification of CsMPs" (QCP) and is based on autoradiography. Here, photostimulated luminescence (PSL) is linearly correlated to the radioactivity of various microparticles, with a regression coefficient of 0.0523 becquerel/PSL/h (Bq/PSL/h). In soil collected from Nagadoro, Fukushima, Japan, CsMPs were detected in soil sieved with a 114 μm mesh. There was no overlap between the radioactivities of CsMPs and clay particles adsorbing Cs. Based on the distribution of radioactivity of CsMPs, the threshold radioactivity of CsMPs in the size fraction of <114 μm was determined to be 0.06 Bq. Based on this method, the number and radioactivity fraction of CsMPs in four surface soils collected from the vicinity of the FDNPP were determined to be 48-318 particles per gram and 8.53-31.8%, respectively. The QCP method is applicable to soils with a total radioactivity as high as ∼106 Bq/kg. This novel method is critically important and can be used to quantitatively understand the distribution and migration of the highly radioactive CsMPs in near-surface environments surrounding Fukushima.
AB - Highly radioactive cesium-rich microparticles (CsMPs) were released from the Fukushima Daiichi nuclear power plant (FDNPP) to the surrounding environment at an early stage of the nuclear disaster in March of 2011; however, the quantity of released CsMPs remains undetermined. Here, we report a novel method to quantify the number of CsMPs in surface soils at or around Fukushima and the fraction of radioactivity they contribute, which we call "quantification of CsMPs" (QCP) and is based on autoradiography. Here, photostimulated luminescence (PSL) is linearly correlated to the radioactivity of various microparticles, with a regression coefficient of 0.0523 becquerel/PSL/h (Bq/PSL/h). In soil collected from Nagadoro, Fukushima, Japan, CsMPs were detected in soil sieved with a 114 μm mesh. There was no overlap between the radioactivities of CsMPs and clay particles adsorbing Cs. Based on the distribution of radioactivity of CsMPs, the threshold radioactivity of CsMPs in the size fraction of <114 μm was determined to be 0.06 Bq. Based on this method, the number and radioactivity fraction of CsMPs in four surface soils collected from the vicinity of the FDNPP were determined to be 48-318 particles per gram and 8.53-31.8%, respectively. The QCP method is applicable to soils with a total radioactivity as high as ∼106 Bq/kg. This novel method is critically important and can be used to quantitatively understand the distribution and migration of the highly radioactive CsMPs in near-surface environments surrounding Fukushima.
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U2 - 10.1021/acs.est.7b06693
DO - 10.1021/acs.est.7b06693
M3 - Article
C2 - 29782160
AN - SCOPUS:85048085238
SN - 0013-936X
VL - 52
SP - 6390
EP - 6398
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 11
ER -