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Battulga, B.; Atarashi-Andoh, Mariko; Nakanishi, Takahiro; Koarashi, Jun
Science of the Total Environment, 849, p.157758_1 - 157758_11, 2022/11
Times Cited Count：3 Percentile：40.21(Environmental Sciences)Characterizing plastic-associated biofilms is key to the better understanding of organic material and mineral cycling in the "Plastisphere"-the thin layer of microbial life on plastics. In this study, we propose a new method to extract biofilms from environmental plastics, in order to evaluate the properties of biofilm-derived organic matter through stable carbon (
C) and nitrogen (
N) isotope signatures and their interactions with radionuclides especially radiocesium (
Cs). After ultrasound-assisted separation from the plastics, biofilm samples were successfully collected via a sequence of syringe treatments. Biofilm-derived organic matter samples (14.5-65.4 mg) from four river mouths in Japan showed Cs activity concentrations of 
75 to 820 Bq kg
biofilm (dw), providing evidence that environmental plastics, mediated by developed biofilms, serve as a carrier for Cs in the coastal environment. Significant differences in the (C and N signatures were also obtained for the biofilms, indicating the different sources, pathways, and development processes of biofilms on plastics.
Kitazawa, Shinichi; Putra, P.; Sakai, Seiji; Narumi, Kazumasa; Naramoto, Hiroshi; Yamamoto, Shunya; Chiba, Atsuya
Nuclear Instruments and Methods in Physics Research B, 206, p.952 - 955, 2003/05
Times Cited Count：6 Percentile：43.05(Instruments & Instrumentation)Pulsed energy impacts are expected to generate the elastic waves reflecting the elastic properties of impacted substances. Among the generated waves, the surface acoustic waves (SAW) can be more specific to the surface structures and can be used effectively in the characterization of thin films in a non-destructive way. In the present study, pulsed laser impacts were employed to generate SAWs on a thin film and the SAWs are detected with a laser reflection technique. To test the effectiveness of this method, an amorphous carbon films were irradiated with 13 keV Ar ions at room temperature in a broad range and the SAW propagation velocity was evaluated as a function of Ar ion dose. The present preliminary experiment using pulsed laser suggests the successful detection of SAW from typical substances with different modulus of elasticity such as fcc metals, oxides and semi conducting materials.
Zhu, X. D.; Naramoto, Hiroshi; Xu, Y.; Narumi, Kazumasa; Miyashita, Kiyoshi*
Physical Review B, 66(16), p.165426_1 - 165426_5, 2002/10
Times Cited Count：14 Percentile：57.54(Materials Science, Multidisciplinary)no abstracts in English
Naramoto, Hiroshi; Xu, Y.; Narumi, Kazumasa; Zhu, X.; Vacik, J.; Yamamoto, Shunya; Miyashita, Kiyoshi*
JAERI-Review 2001-039, TIARA Annual Report 2000, p.183 - 185, 2001/11
no abstracts in English
Zhang, Z.; Narumi, Kazumasa; Naramoto, Hiroshi
Applied Physics Letters, 79(18), p.2934 - 2936, 2001/10
Times Cited Count：0 Percentile：0(Physics, Applied)no abstracts in English
Zhang, Z.; Narumi, Kazumasa; Naramoto, Hiroshi
Journal of Physics; Condensed Matter, 13(22), p.L425 - L481, 2001/06
no abstracts in English
Zhang, Z.*; Narumi, Kazumasa; Naramoto, Hiroshi; Wu, Z.*; Yamamoto, Shunya; Miyashita, Atsumi; Tamada, Masao
Journal of Applied Physics, 86(3), p.1317 - 1321, 1999/08
Times Cited Count：11 Percentile：48.49(Physics, Applied)no abstracts in English
Zhang, Z.; Narumi, Kazumasa; Naramoto, Hiroshi; Wu, Z.*; Yamamoto, Shunya; Miyashita, Atsumi
Journal of Physics; Condensed Matter, 11(25), p.L273 - L277, 1999/06
Times Cited Count：3 Percentile：13.27(Physics, Condensed Matter)no abstracts in English
Kameo, Yutaka
Proceedings of OECD/NEA Workshop on Evaluation of Speciation Technology, p.241 - 245, 1999/00
no abstracts in English
Battulga, B.; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Plastic debris has been recognized as one of the carriers of hazardous substances in the aquatic ecosystem due to its ubiquitous distribution and potential interaction with pollutants through developed biofilms. In this study, we aimed to extract biofilms from the environmental plastics using a newly developed extraction method and to determine the concentration of radiocesium (Cs) and stable isotope ratios (C and N) in the extracted biofilm samples. Visible plastics were collected from the mouths of coastal rivers in Ibaraki prefecture, Japan, and applied to the extraction procedures. After plastic and biofilm separation with ultrasonication, biofilm samples were collected by the two ways: freeze-drying (15.5-44.4 mg); and freeze-drying after syringe treatment (14.5-65.4 mg). The XRD diffractograms of biofilm samples confirmed that biofilms obtained by freeze-drying only were still heterogeneous and the agglomerations of organic substances, mineral particles, and small microplastics (MPs, 1 mm). The results also demonstrated that biofilm extraction was achieved by syringe treatment separating the mineral and small MPs particles, resulting in homogenous biofilms from the surface of plastics. Preliminarily results of Cs activity concentrations in heterogenous (ranging from 0.22 to 0.54 Bq g) and homogenous (0.82
0.04 Bq g) biofilm samples revealed that MPs serve as a carrier for Cs in the coastal river environment mediated by developed biofilms.
Battulga, B.; Nakayama, Masataka; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Plastic debris in the aquatic environment has become a growing concern due to their long-term ecological consequences. The current study is focused on microbial community composition on microplastics (MPs; sizes 5 mm) and characteristics of MP-associated biofilms in coastal river environments of Japan in order to understand the impact of MP-associated biofilms on aquatic organic matter cycling. The aims of the current study are i) extraction and characterization of microbial biofilms on MPs and ii) identification of diversity and composition of microbial communities on MP surfaces and in surrounding surface waters and sediments. The samples were collected from two coastal rivers during 2021-2022 on a seasonal basis. In this study, we proposed a new method to extract biofilms from MPs using ultrasound-assisted syringe treatment for isotopic analysis. Morphotypes of MPs and associated specific microbial taxa as well as seasonal differences were also observed.
