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Cs in a river-sea system boundary area after the Fukushima Dai-ichi Nuclear Power Plant accidentTakata, Hyoe*; Wakiyama, Yoshifumi*; Wada, Toshihiro*; Hirao, Shigekazu*; Aono, Tatsuo*; Nakanishi, Takahiro; Misono, Toshiharu; Shiribiki, Takehiko; Aoyama, Michio*
Marine Chemistry, 262, p.104384_1 - 104384_6, 2024/05
Yanagisawa, Kayo; Matsueda, Makoto; Furukawa, Makoto*; Ishiniwa, Hiroko*; Wada, Toshihiro*; Hirata, Takafumi*; Takagai, Yoshitaka*
Analyst, 148(18), p.4291 - 4299, 2023/09
Times Cited Count：0 Percentile：0(Chemistry, Analytical)Quantitative imaging of trace elements was successfully performed by online isotope dilution laser ablation inductively coupled plasma mass spectrometry (online LA-ICP-IDMS). The sample aerosols produced by LA are mixed online with the mist created from an isotopically enriched spike solution via an in-house cyclonic spray chamber, which has a gas port on the top. Quantification was continuously achieved in each spot; subsequently, quantitative imaging was realized. Fe and Sr were selected as the model elements, and their spot quantifications based on online-isotope dilution. The method was applied to actual biological hard tissues, and the results were compared with electron probe microanalyzer data.
Tatsuno, Takahiro*; Waki, Hiromichi*; Kakuma, Minato*; Nihei, Naoto*; Takase, Tsugiko*; Wada, Toshihiro*; Yoshimura, Kazuya; Nakanishi, Takahiro; Ote, Nobuhito*
Journal of Environmental Management, 329, p.116983_1 - 116983_13, 2023/03
Times Cited Count：1 Percentile：12.42(Environmental Sciences)Tatsuno, Takahiro*; Waki, Hiromichi*; Kakuma, Minato*; Nihei, Naoto*; Wada, Toshihiro*; Yoshimura, Kazuya; Nakanishi, Takahiro; Ote, Nobuhito*
Radiation Protection Dosimetry, 198(13-15), p.1052 - 1057, 2022/09
Times Cited Count：1 Percentile：27.23(Environmental Sciences)Cs concentrations in coastal sediments off FukushimaSuzuki, Shotaro*; Amano, Yosuke*; Enomoto, Masahiro*; Matsumoto, Akira*; Morioka, Yoshiaki*; Sakuma, Kazuyuki; Tsuruta, Tadahiko; Kaeriyama, Hideki*; Miura, Hikaru*; Tsumune, Daisuke*; et al.
Science of the Total Environment, 831, p.154670_1 - 154670_15, 2022/07
Times Cited Count：2 Percentile：25.78(Environmental Sciences)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：38.08(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.
Chaboche, P.-A.*; Wakiyama, Yoshifumi*; Takata, Hyoe*; Wada, Toshihiro*; Evrard, O.*; Misono, Toshiharu; Shiribiki, Takehiko; Funaki, Hironori
no journal, ,
Chaboche, P.-A.*; Wakiyama, Yoshifumi*; Takata, Hyoe*; Wada, Toshihiro*; Evrard, O.*; Misono, Toshiharu; Shiribiki, Takehiko; Funaki, Hironori
no journal, ,
Yanagisawa, Kayo; Matsueda, Makoto; Furukawa, Makoto*; Ishiniwa, Hiroko*; Wada, Toshihiro*; Hirata, Takafumi*; Takagai, Yoshitaka*
no journal, ,
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is more sensitive than other imaging analysis methods. The method requires matrix-compatible certified reference materials (CRMs) for the quantification of target elements. However, CRMs suitable for biological samples are rarely commercially available, making quantification difficult with conventional LA-ICP-MS methods. This study used a dual gas flow system combined with an isotope dilution method. In this system, two aerosols, an ablation sample and a nebulised spike solution, are mixed via a proprietary dual-port chamber. The developed method was used to quantify Fe and Sr in the CRMs and agreed with the certified values. In addition, biological samples (teeth and otoliths) were analysed and compared with values obtained by conventional chemical analysis to demonstrate their potential application for quantitative mapping.
Cs in a river-sea system boundary areaTakata, Hyoe*; Wada, Toshihiro*; Wakiyama, Yoshifumi*; Hirao, Shigekazu*; Sato, Shun*; Aono, Tatsuo*; Nakanishi, Takahiro; Misono, Toshiharu; Shiribiki, Takehiko
no journal, ,
Chaboche, P.-A.*; Wakiyama, Yoshifumi*; Takata, Hyoe*; Wada, Toshihiro*; Misono, Toshiharu; Shiribiki, Takehiko; Funaki, Hironori
no journal, ,
The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) incident, triggered by the Great East Japan Earthquake and subsequent tsunami in March 2011, resulted in the release of significant quantities of radionuclides into the terrestrial and marine environments of Fukushima Prefecture. While the activity of radiocesium (i.e., 
Cs and Cs) in these environments has decreased since the accident, continuous inputs through rivers draining and eroding the main terrestrial radioactive plume have been measured, maintaining elevated levels of Cs in riverine and coastal sediment deposited off the Prefecture's coast. Consequently, identifying the sources of sediment is required to elucidate the links between terrestrial and marine radiocesium dynamics and to anticipate the fate of persistent radionuclides in the environment.
