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Sr in human teeth and marine fish bonesKoarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Terashima, Motoki
KEK Proceedings 2023-2, p.155 - 160, 2023/11
In this presentation, we report the results of the application of the Y-separation method using DGA resin to the determination of Sr in human teeth and seawater fish bones.
Sr and 
Cs into wild animals after the Fukushima Daiichi Nuclear Power Plant accident using hard tissue as an indicatorKoarai, Kazuma
Hosha Kagaku, (47), p.24 - 27, 2023/03
Ca-based tissues, such as teeth and bones, are called hard tissues. Sr is incorporated into the tooth during calcification. Once incorporated, it remains until the tooth falls out. Therefore, Sr in teeth recorded Sr contamination by the 1F accident in the environment during the formation period. The article presents current research findings.
-CO mixed-gas reaction in inductively coupled plasma tandem quadrupole mass spectrometryMatsueda, Makoto; Aoki, Jo; Koarai, Kazuma; Terashima, Motoki; Takagai, Yoshitaka*
Analytical Sciences, 38(11), p.1371 - 1376, 2022/11
Times Cited Count：2 Percentile：15.48(Chemistry, Analytical)The 
I analysis using ICP-MS is challenging caused by xenon-129 (Xe) and 
IH generated from excess stable isotope I. In this study, mass discrimination between iodine-129 (I) and interfering substances was achieved by inductively coupled plasma-tandem quadrupole mass spectrometry (ICP-MS/MS) with a dynamic reaction cell introduced a mixture gas of O and CO. As a result, the ratio of (background noise intensity at m/z 129)/I was 3.8 
10
and 10 mBq/L of I was analyzed without chemical separation in the presence of 100 mg/L stable I. Spiked tests with actual rainwater were performed, and obtained values were agreed with the spiked amounts.
Sr with ICP-MS/MS using O and NH
mixed gas reactionKoarai, Kazuma; Matsueda, Makoto; Terashima, Motoki
KEK Proceedings 2022-2, p.102 - 107, 2022/11
Analytical methods with inductively coupled plasm mass spectrometry (ICP-MS) have been developed for the determination of Sr in environmental samples; however, the sensitivity of the ICP-MS methods and removal of interferences are insufficient to measure trace amount of Sr in the environmental samples. In this study, we developed an analytical method for Sr with ICP-DRC-MS/MS using oxygen and ammonia mixed gas reaction. This analytical method could be applied for measurement of Sr in reference soil.
Reactions to Achieve Mass-spectrometric Discrimination in Simultaneous Plutonium-isotope Speciation with Inductively Coupled Plasma-Tandem Mass SpectrometryMatsueda, Makoto; Kawakami, Tomohiko*; Koarai, Kazuma; Terashima, Motoki; Fujiwara, Kenso; Iijima, Kazuki; Furukawa, Makoto*; Takagai, Yoshitaka*
Chemistry Letters, 51(7), p.678 - 682, 2022/07
Times Cited Count：5 Percentile：61.39(Chemistry, Multidisciplinary)New methodology for a simultaneous isotope speciation of various Pu isotopes without complicated isobaric interferences is developed by using inductively coupled plasma-mass spectrometry (ICP-MS). In analyzing ICP tandem MS (ICP-MS/MS), CO gas reactions in a dynamic reaction cell (DRC) almost eliminated the background noise intensity produced by isobaric interference from isotopes originating from actinides such as Am, Cm, and U at the locations (m/z) of significant Pu isotopes (
Pu, 
Pu, 
Pu, 
Pu, 
Pu).
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; Sasaki, Keiichi*; et al.
Journal of Radiation Research (Internet), 63(4), p.609 - 614, 2022/07
Times Cited Count：1 Percentile：27.14(Biology)Electron spin resonance (ESR) dosimetry is one of the most powerful tools for radiation dose reconstruction. The detection limit of this technique using human teeth is reported to be 56 mGy or 67 mGy; however, the absorbed dose of Fukushima residents after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident was estimated to be lower than this detection limit. Our aim is to assess the absorbed radiation dose of children in Fukushima Prefecture after the accident; therefore, it is important to estimate the detection limit for their teeth. The detection limit for enamel of deciduous teeth of Japanese children separated by the mechanical method is estimated to be 115.0 mGy. The density separation method can effectively separate enamel from third molars of Japanese people. As we have collected thousands of teeth from children in Fukushima, the present technique may be useful to examine their external absorbed dose after the FNPP accident.
Cs activity concentration in the aquatic insect 
(Tricoptera: Stenopsychidae) in the Ota River, Fukushima, JapanIshii, Yumiko*; Miura, Hikaru*; Jo, J.*; Tsuji, Hideki*; Saito, Rie; Koarai, Kazuma; Hagiwara, Hiroki; Urushidate, Tadayuki*; Nishikiori, Tatsuhiro*; Wada, Toshihiro*; et al.
PLOS ONE (Internet), 17(5), p.e0268629_1 - e0268629_17, 2022/05
Times Cited Count：3 Percentile：43.07(Multidisciplinary Sciences)We investigated the variability in Cs activity concentration in individual aquatic insects in detritivorous caddisfly () and carnivorous dobsonfly (
) larvae from the Ota River, Fukushima. Caddisfly larvae showed sporadically higher radioactivity, whereas no such outliers were observed in dobsonfly larvae. Autoradiography and scanning electron microscopy analyses confirmed that these caddisfly larvae samples contained radiocesium-bearing microparticles (CsMPs), which are insoluble Cs-bearing silicate glass particles. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Although CsMPs distribution and uptake by organisms in freshwater ecosystems is relatively unknown, our study demonstrates that CsMPs can be taken up by aquatic insects.
Sr in hard tissue samplesKoarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Fujiwara, Kenso; Terashima, Motoki
KEK Proceedings 2021-2, p.140 - 145, 2021/12
Strontium-90 and Y, its daughter nuclide, adverse effects on the bone marrow. Monitoring of Sr in the bones have been required after the Fukushima-Daiichi Nuclear Power Plant accident. However, conventional radioactivity measurement method for Sr requires a complicated separation of Y and a time-consuming measurement. ICP-MS system has been applied to Sr concentration survey of water, soil, and edible part of fish. We developed measurement method of Sr with ICP-MS and applied the method for cattle bones. We determined Sr in the hard tissues of animals that collected in the Fukushima prefecture. Limit of detection in the measurement was 19 Bq/kg.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
KEK Proceedings 2021-2, p.91 - 96, 2021/12
We examined whether the ESR dose estimation method could be applied to wild Japanese macaque. In this work, we investigated the enamel preparation protocol and the analytical method of the ESR spectra.
Sr in cattle bone and tooth samples by inductively coupled plasma mass spectrometryKoarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Terashima, Motoki; Fujiwara, Kenso; Kino, Yasushi*; Oka, Toshitaka; Takahashi, Atsushi*; Suzuki, Toshihiko*; et al.
Journal of Analytical Atomic Spectrometry, 36(8), p.1678 - 1682, 2021/08
Times Cited Count：5 Percentile：55.72(Chemistry, Analytical)Rapid analysis of Sr in bone and tooth samples of cattle were achieved by an inductively coupled plasma mass spectrometry (ICP-MS) coupled with mass shift and solid phase extraction techniques. Limit of detection (LOD) in the ICP-MS measurement of 0.1 g samples was lower than that of the radioactivity measurement. Analytical time of the ICP-MS method was reduced from 20 days to 11 hours, compared with the radiometric method. Therefore, the ICP-MS method can be rapid and useful procedure of Sr in small bone and tooth samples derived from terrestrial animals.
Matsueda, Makoto; Yanagisawa, Kayo*; Koarai, Kazuma; Terashima, Motoki; Fujiwara, Kenso; Abe, Hironobu; Kitamura, Akihiro; Takagai, Yoshitaka*
ACS Omega (Internet), 6(29), p.19281 - 19290, 2021/07
Times Cited Count：2 Percentile：14.88(Chemistry, Multidisciplinary)Online solid-phase extraction-inductively coupled plasma-quadrupole mass spectrometry with oxygen dynamic reaction cell (online SPE-ICP-MS-DRC) was shown to be a thorough automatic analytical system, circumventing the need for human handling. At three stepwise separations (SPE-DRC-Q mass filters), we showed that interference materials allowed the coexistence of abundance ratios of 1.510
for 
Tc/Mo. Using this optimized system, a detection limit of Tc was 9.3 pg/L (5.9 mBq/L) for a 50 mL injection and sequential measurements were undertaken at a cycle of 24 min/sample.
Aoki, Jo; Matsueda, Makoto; Koarai, Kazuma; Terashima, Motoki; Fujiwara, Kenso; Abe, Hironobu
JAEA-Research 2021-002, 20 Pages, 2021/05
JAEA-Research-2021-002.pdf:2.75MB
In order to analyze extremely low concentrations of I in environmental samples by ICP-MS with high sensitivity and rapidity, it is necessary to remove interfering elements (Na, Mg, K, Ca, Mo, Cd and In) using a pretreatment method with Solid-phase Extraction Resin. Anion Exchange Resins with amino groups have been widely used as Solid-phase Extraction Resins, while Ag+ Supported Resins have also been widely used in recent years. It is necessary to optimize the pretreatment technique based on characteristics of the resins. In this study, we compared in terms of separation of I from matrix elements (Na, Mg, K, Ca, Mo, Cd and In) for DOWEX1-X8, AG 1-X8 and CL Resin, and investigated their suitability for ICP-MS analysis of I in environmental samples. The results of adsorption and elution experiments showed that all resins examined uptake and elute I quantitatively. CL Resin showed the highest removal performance of interfering elements, with 3.1% of Mo remaining, but other interfering elements were removed below the detection limit of ICP-MS. However, the Mo remained after the CL Resin treatment could interfere the ICP-MS measurement of I, based on the consideration of ratio of I and Mo. The eluate from CL Resin was treated with a Cation exchange resin (DOWEX 50WX8). As a result, Mo in the eluate was removed by up to 98% and the interference from Mo was reduced to measurable level. Therefore, the pretreatment method using CL Resin in combination with DOWEX 50WX8 is effective for ICP-MS analysis of I at extremely low concentrations (background level).
Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.
Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05
Times Cited Count：6 Percentile：41.49(Multidisciplinary Sciences)Sr in hard tissue samplesKoarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Fujiwara, Kenso; Terashima, Motoki; Kitamura, Akihiro; Abe, Hironobu
KEK Proceedings 2020-4, p.180 - 185, 2020/11
Strontium-90 and Y, its daughter nuclide, adverse effects on the bone marrow. Monitoring of Sr in the bones have been required after the Fukushima-Daiichi Nuclear Power Plant accident. However, conventional radioactivity measurement method for Sr requires a complicated separation of Y and a time-consuming measurement. ICP-MS system has been applied to Sr concentration survey of water, soil, and edible part of fish. We applied the ICP-MS system for the bones for the first time. In this study, reference bone (JSAC 0785 fish bone) was used as measurement samples. Sample preparation of the bone was performed using a microwave digestion instrument. After sample preparation, Sr was determined using ICP-MS system with cascade separation steps based on on-line column separation and oxygen reaction. Strontium-90 in the bones was successfully separated from Ca, Ba, Y, Zr, Fe, Se, and Ge, which interfered in ICP-MS measurement, in the separation steps.
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Mitsuyasu, Yusuke*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; et al.
Radiation Measurements, 134, p.106315_1 - 106315_4, 2020/06
Times Cited Count：5 Percentile：53.85(Nuclear Science & Technology)The relationship between the CO radical intensity and the absorbed dose (dose response curve) of tooth enamel of Japanese macaque was observed by electron spin resonance and the detection limit of our system was estimated to be 33.5 mGy, which is comparable to the detection limit for human molar teeth. Using the dose response curve, external exposure dose for seven wild Japanese macaques captured in Fukushima prefecture were examined. The results suggest that the external exposure dose for the wild Japanese macaques were ranged between 45 mGy to 300 mGy.
Koarai, Kazuma
Hosha Kagaku, (40), p.26 - 27, 2019/09
Report about "The 20th Workshop on Environmental Radioactivity" was submitted in 
. There were 195 participants in the workshop. They actively discussed environmental radioactivity and pollution after the Fukushima-Daiichi Nuclear Power Plant. Presentation awards were given to 4 persons.
Sr and Cs in hard tissues of cattle and monkey in the Fukushima environmentKoarai, Kazuma
Hosha Kagaku, (40), p.34 - 36, 2019/09
Abstract of doctor thesis was submitted to "Hoshakagaku", which is Japanese article. I described main theme of the thesis. The hard tissues of the animals incorporated at the development stage and bone methabolism of the tissues. On the other hand, Cs was incorporated not only the development stage but also after the stage. Strontium-90 and cesium-137 in the cattle teeth reflected the pollution after the Fukushima-Daiichi Nuclear Power Plant accident. The thesis showed and Cs in the hard tissues would an important indicator of the environmental pollution.
Sr in animal bone by ICP-MSKoarai, Kazuma; Matsueda, Makoto; Yanagisawa, Kayo*; Fujiwara, Kenso; Kitamura, Akihiro
no journal, ,
Strontium-90 and Y, its daughter nuclide, adverse effects on the bone marrow. Monitring of Sr have been required after the Fukushima-Daiichi Nuclear Power Plant. However, radioactivity measurement method requires a complicated separation and a time-consuming 
-ray measurement. ICP-MS system has been applied to Sr contamination survey of soil and water samples. We applied the ICP-MS system for the bones for the first time. In this study, reference bone was used as measurement samples. After sample preparation, Sr was determined using ICP-MS system with cascade separation steps based on on-line column separation and oxygen reaction. Strontium-90 in the bones was successfully separated from Ca, Ba, Y, Zr, Fe, and Ge, which interfered in ICP-MS measurement, in the separation steps. We found that the ICP-MS system could be applied to the rapid measurement of Sr in the bones.
Sr in bones for ICP-MS analysisKoarai, Kazuma; Matsueda, Makoto; Yanagisawa, Kayo*; Fujiwara, Kenso; Kitamura, Akihiro
no journal, ,
Strontium-90 (Sr) is one of an artificial radionuclide after the Fukushima-Daiichi Nuclear Power Plant accident. The ICP-MS system for Sr have been developed. The ICP-MS system could apply to measurement of Sr in soils and water. In this study, solid phase extraction method of Sr was optimized the ICP-MS system for bones. After MW digestion, fish bone was dissolved in 2.6 M nitric acid. Sr resin was used for solid phase extraction of Sr in a flow-injection system. Sr and interference elements were determined with ICP-MS. Chemical yield of Sr was over 90% in the solid phase extraction system. Interference elements were removed in the extraction. The extraction method could applied to the ICP-MS system for Sr. The method required only 30 minutes. The ICP-MS system would be rapid method for Sr measurement in bones.
Matsueda, Makoto; Koarai, Kazuma; Yanagisawa, Kayo*; Fujiwara, Kenso; Kitamura, Akihiro
no journal, ,
Sr-90 accumulates in hard tissues such as bones and teeth in the case of uptake into the human or animal bodies. Therefore, the analysis of these hard tissues from the viewpoint of exposure evaluation has required, but the conventional radioactivity analysis requires a period of about one month, it is difficult to process a large number of samples. From this thing, we tried to apply application of the online solid phase extraction/ICP-MS method which can be measured quickly compared to radioactivity analysis. This method has mainly been utilizing as the analysis of Sr-90 contained in the water samples such as rainwater, and it has already equipped the correction functions corresponding to the shift of recovery rate at the Sr resin and the sensitivity shift in ICP-MS. However, hard tissues contain a large amount of matrix. Therefore, we investigated whether the isobaric interference, stable Sr, and other high matrix influence to Sr-90 values and attempted to correct the values.
