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Dohi, Terumi; Iijima, Kazuki; Machida, Masahiko; Suno, Hiroya*; Omura, Yoshihito*; Fujiwara, Kenso; Kimura, Shigeru*; Kanno, Futoshi*
Environmental radiochemical analysis VII, p.50 - 57, 2023/12
microscale localisation observationDohi, Terumi; Iijima, Kazuki; Machida, Masahiko; Suno, Hiroya*; Omura, Yoshihito*; Fujiwara, Kenso; Kimura, Shigeru*; Kanno, Futoshi*
PLOS ONE (Internet), 17(7), p.e0271035_1 - e0271035_21, 2022/07
Times Cited Count：1 Percentile：14.8(Multidisciplinary Sciences)Dohi, Terumi; Omura, Yoshihito*; Yoshimura, Kazuya; Sasaki, Takayuki*; Fujiwara, Kenso; Kanaizuka, Seiichi*; Nakama, Shigeo; Iijima, Kazuki
PLOS ONE (Internet), 16(5), p.e0251828_1 - e0251828_16, 2021/05
Times Cited Count：6 Percentile：41.49(Multidisciplinary Sciences)Dohi, Terumi; Tagomori, Hisaya; Omura, Yoshihito*; Fujiwara, Kenso; Kanaizuka, Seiichi*; Iijima, Kazuki
Environmental Radiochemical Analysis VI, p.58 - 70, 2019/09
In this study we established a separation method for radiocaesium-bearing microparticles (CsMPs) from lichens using electron microscopic analysis. Lichens were first digested within hydrogen peroxide and then an automatic particle analyser system based on FE-EPMA was used for detecting CsMPs within lots of mineral-like and metallic particles quickly. The elemental composition and radiocaesium activities of the separated CsMPs were measured, and the results show that the digestion treatment did not influence the CsMPs characteristics. An inhomogeneous elemental distribution was found in some CsMPs by two-dimensional elemental analysis using FE-EMPA. Our methods for separation of CsMPs and analysing their elemental composition are expected to be useful for grasping the chemical composition trends of CsMPs statistically.
Dohi, Terumi; Omura, Yoshihito*; Kashiwadani, Hiroyuki*; Fujiwara, Kenso; Sakamoto, Yoshiaki; Iijima, Kazuki
Journal of Environmental Radioactivity, 146, p.125 - 133, 2015/08
Times Cited Count：20 Percentile：52.45(Environmental Sciences)Radiocaesium activity concentrations (
Cs, 
Cs) were measured in parmelioid lichens collected within the Fukushima Prefecture approximately 2 y after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. A total of 44 samples consisting of nine species were collected at 16 points within a 60 km radius of the FDNPP. The activity concentration of Cs ranged from 4.6 to 1000 kBq kg
and for Cs ranged from 7.6 to 1740 kBq kg. A significant positive correlation was found between the Cs activity concentration in lichens and the Cs deposition density on soil, based on the calculated Spearman's rank correlation coefficients as 
= 0.90 (
0.01). The two dominant species, Flavoparmelia caperata and Parmotrema clavuliferum, showed strong positive correlations, for which the r values were calculated as 0.92 ( 0.01) and 0.90 ( 0.01) respectively. Therefore, they are suggested as biomonitoring species for levels of radiocaesium fallout within the Fukushima Prefecture.
Dohi, Terumi; Omura, Yoshihito*; Kashiwadani, Hiroyuki*; Fujiwara, Kenso; Sakamoto, Yoshiaki; Iijima, Kazuki
Raiken, 18(1), p.11 - 13, 2014/12
no abstracts in English
Ishizumi, Taichiro*; Usuda, Jitsuo*; Inoue, Tatsuya*; Iijima, Yoshihito*; Maehara, Sachio*; Furumoto, Hideyuki*; Oka, Kiyoshi; Ikeda, Norihiko*
no journal, ,
no abstracts in English
Dohi, Terumi; Omura, Yoshihito*; Kashiwadani, Hiroyuki; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
no abstracts in English
Dohi, Terumi; Omura, Yoshihito*; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
Lichens are symbiotic organisms consisted of fungi and algae. A number of studies were carried out after the nuclear weapons tests and Chernobyl accident, and demonstrated that lichens were useful for indicator of radioactive fallout because they could take up large amount of radionuclides directly from their thallus due to lack of root system and retain them. However, in order to measure radiocaesium concentration in lichen, the lichen sample was collected from their habitat. Therefore, temporal change of radiocaesium concentration in same lichen individual has never reported. In addition, a retention of radiocaesium in lichens in Japan was unknown. The objective of this study is to investigate the temporal change of radiocaesium concentration in individual lichen. Lichen samples were parmelioid lichens which were grown on the trunk of Prunus spp. within Fukushima prefecture. The counting rate of surface of lichen was measured by using Geiger-Mueller (GM) survey meter with a lead collimator to evaluate the radiocaesium concentration. The contamination density in lichens increased from the initial measurement value after one year. It is considered that lichen may receive radiocaesium from stem flow including radiocaesium desorbed from canopy or stem.
Cs in lichens after the Fukushima Nuclear AccidentDohi, Terumi; Omura, Yoshihito*; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
Large quantity of radionuclides, including Cs and Cs, were released into the atmosphere caused by the Fukushima Dai-chi Nuclear Power Plant (FDNPP) accident on March 11, 2011. As lichens are known to be effective tools to monitor environmental radioelements in both time and space, lichen samples are expected to be used to examine and monitor radiocaesium fallout from FDNPP in Japan. The purpose of this study is to discuss the estimation of radiocaesium fallout in the ecosystem based on the following examinations using lichens. Fifty-eight samples including foliose and fruticose lichens were collected from northern to central Japan especially focusing on Fukushima Prefecture during 2012 and 2013. After correction for radioactive decay (on each sampling date), the detected radiocaesium concentrations ranged from 16.1 Bq kg (d.w.) to 510,000 Bq kg for Cs and from 33.8 to 880,000 Bq kg for Cs in lichens. Cs concentration in the lichen samples generally increased with increase in the amount of fallout estimated by the Cs deposition in soil. The positive correlation was supported between Cs in lichens collected from Fukushima Prefecture and Cs inventories on soil calculated by Inverse Distance Weighted with Spearman's rank correlation coefficient (0.90, p 0.01). The activity ratios of Cs and Cs for the lichen samples (
= 44) collected within Fukushima Prefecture (decay corrected to March 11, 2011) were between 0.95
0.04 and 1.080.41. The ratios are consistent with those for radiocaesium derived from the FDNPP accident (reported as 0.89 to 1.2). The ratios obtained from lichen samples collected in outside of Fukushima Prefecture were 0.750.23 to 1.480.48. They were consistent with those from Fukushima. But one sample showing significantly small value, 0.480.16, might be influenced by different origin from Fukushima.
Dohi, Terumi; Fujiwara, Kenso; Omura, Yoshihito*; Iijima, Kazuki
no journal, ,
In this study, we investigated the condition of radiocaesium deposition and the constituent element of particles on lichen thalli.
collected around the Fukushima Dai-ichi Nuclear Power PlantDohi, Terumi; Omura, Yoshihito*; Fujiwara, Kenso; Kikuchi, Naoyuki; Iijima, Kazuki
no journal, ,
A plenty of various radionuclides was released into the atmosphere by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. The local radioactive contaminations (i.e. radioactive plume's trajectory) around the FDNPP were caused by the releasing radionuclides from each reactor, meteorological and geographical conditions, etc. In order to clarify the contamination characteristics of the plume's trajectory, we focused on lichen samples that are well known organism to retain radionuclides for a long period. A field investigation was carried out around the FDNPP on January 2016. , a common species at the area, growing on trunks of trees was collected around the FDNPP. The fragments of lichen thalli were analyzed by the scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEM-EDS). Heavy metal particles were detected on the surface of
. They might originate from reactors of the FDNPP because they contain anthropogenic elements such as, (Fe, Zn), (Cd, Zn), (Zr, Ti), (Fe, Zn, Cr), (Ti, Fe, Ce), (Fe, Ti, Cr, Ni), (Fe, Cr, Zn, Cd), etc. Further data of the elemental composition in particles on lichen samples would be helpful to discuss the differences among the radioactive plume's trajectories from each reactor.
Iijima, Kazuki; Dohi, Terumi; Niizato, Tadafumi; Fujiwara, Kenso; Koma, Yoshikazu; Suzuki, Shinichi; Oda, Yoshihiro; Omura, Yoshihito*; Sasaki, Takayuki*; Namba, Kenji*
no journal, ,
For the purpose of estimation of radionuclides inventory in the various radioactive solid wastes, such as soils, trees, generated from decommissioning of Fukushima Daiichi Nuclear Power Station (FDNPS), the methodology of estimation of on-site radionuclides inventories is being developed based on the dependency on distance and direction from the FDNPS of their off-site distribution.
Dohi, Terumi; Iijima, Kazuki; Omura, Yoshihito*; Fujiwara, Kenso; Kikuchi, Naoyuki*
no journal, ,
The local radioactive contaminations (i.e. radioactive plume's trace) around the FDNPS were caused by the releasing radionuclides from each reactor, weather conditions, etc. Japan Atomic Energy Agency is carrying out the project to evaluate off-site distribution of radionuclides and to determine the origin of plume's traces at each point, since we develop the model to estimate on-site distribution. As lichens are known to be effective tools to monitor environmental radionuclides in both time and space because of their ability to retain radionuclides for a long period, lichen samples are expected to be used to examine initial fallout distribution. The purpose of this study is to measure radionuclides concentrations in lichens and analyse elemental composition in particles captured on lichen thalli, in order to evaluate initial distribution of radionuclides and clarify the contamination characteristics of the plume's traces nearby the FDNPS.
Dohi, Terumi; Tagomori, Hisaya; Omura, Yoshihito*; Kanaizuka, Seiichi*; Fujiwara, Kenso; Iijima, Kazuki
no journal, ,
no abstracts in English
Dohi, Terumi; Fujiwara, Kenso; Omura, Yoshihito*; Tagomori, Hisaya*; Iijima, Kazuki; Kitamura, Akihiro
no journal, ,
Dohi, Terumi; Iijima, Kazuki; Machida, Masahiko; Suno, Hiroya*; Omura, Yoshihito*; Fujiwara, Kenso; Kimura, Shigeru*; Kanno, Futoshi*
no journal, ,
no abstracts in English
Dohi, Terumi; Iijima, Kazuki; Machida, Masahiko; Suno, Hiroya*; Omura, Yoshihito*; Fujiwara, Kenso; Kimura, Shigeru*; Kanno, Futoshi*
no journal, ,
no abstracts in English
