Novel Method of Quantifying Radioactive Cesium-Rich Microparticles (CsMPs) in the Environment from the Fukushima Daiichi Nuclear Power Plant
Journal
Environmental Science & Technology
Journal Volume
52
Journal Issue
11
Start Page
6390
End Page
6398
ISSN
0013-936X
1520-5851
Date Issued
2018-05-21
Author(s)
Ikehara, Ryohei
Suetake, Mizuki
Komiya, Tatsuki
Furuki, Genki
Ochiai, Asumi
Yamasaki, Shinya
Bower, William R.
Law, Gareth T. W.
Ohnuki, Toshihiko
Grambow, Bernd
Ewing, Rodney C.
Abstract
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.
Subjects
Cesium
Cesium Radioisotopes
Fukushima Nuclear Accident
Japan
Nuclear Power Plants
Radiation Monitoring
Radioactivity
Fukushima [Tohoku]
Honshu
Tohoku
Nuclear energy
Nuclear fuels
Nuclear power plants
Radiation
Radiography
Soils
cesium 134
cesium 137
silicon dioxide
cesium
Clay particles
Fukushima dai-ichi nuclear power plants
Micro-particles
Near surfaces
Photo stimulated luminescence
Radioactive cesiums
Regression coefficient
Surrounding environment
luminescence
nanoparticle
natural disaster
nuclear power plant
numerical method
radioactivity
adsorption
Article
autoradiography
calibration
controlled study
energy dispersive X ray spectroscopy
Fukushima nuclear accident
gamma spectrometry
limit of quantitation
particle size
radiation dose
radiation safety
radioactive contamination
scanning electron microscopy
soil pollution
surface soil
validity
radiation monitoring
SDGs
Publisher
American Chemical Society (ACS)
Type
journal article