NAKAGUCHI Yuzuru

    Department of Science Professor
Last Updated :2024/03/24

Researcher Information

Degree

  • (BLANK)

URL

J-Global ID

Research Interests

  • Ocean chemistry   Geochemistry   

Research Areas

  • Natural sciences / Atmospheric and hydrospheric science
  • Natural sciences / Human geoscience

Academic & Professional Experience

  • 2011/04 - Today  Kindai UniversitySchool of Science and EngineeringProfessor
  • 2007/04 - 2011/03  Kindai UniversitySchool of Science and EngineeringAssociate Professor
  • 2002/04 - 2007/03  Kindai UniversitySchool of Science and EngineeringAssistant professor
  • 1996/04 - 2002/03  Kindai UniversitySchool of Science and EngineeringLecturer
  • 1986/04 - 1996/03  Kindai UniversitySchool of Science and EngineeringAccistant

Education

  • 1984/04 - 1986/03  Kinki University  Graduate School of Chemistry  Doctor couse
  • 1982/04 - 1984/03  Kinki University  Graduate School of Chemistry  Master couse
  • 1978/04 - 1982/03  Kinki University  School of Science and Engineering  Department of Chemistry

Association Memberships

  • JAPAN SOCIETY FOR ATMOSPHERIC ENVIRONMENT   THE JAPAN SOCIETY FOR ANALYTICAL CHEMISTRY   THE OCEANOGRAPHIC SOCIETY OF JAPAN   THE GEOCHEMICAL SOCIETY OF JAPAN   

Published Papers

  • Yuzuru Nakaguchi; Atsushi Sakamoto; Takuya Asatani; Tomoharu Minami; Kiminori Shitashima; Linjie Zheng; Yoshiki Sohrin
    Marine Chemistry Elsevier BV 241 104108 - 104108 0304-4203 2022/04 [Refereed]
  • Yuzuru Nakaguchi; Yoshinori Ikeda; Atsushi Sakamoto; Linjie Zheng; Tomoharu Minami; Yoshiki Sohrin
    Journal of Oceanography Springer Science and Business Media LLC 0916-8370 2020/11 [Refereed]
  • Reiner Schlitzer; Robert F. Anderson; Elena Masferrer Dodas; Maeve Lohan; Walter Geibert; Alessandro Tagliabue; Andrew Bowie; Catherine Jeandel; Maria T. Maldonado; William M. Landing; Donna Cockwell; Cyril Abadie; Wafa Abouchami; Eric P. Achterberg; Alison Agather; Ana Aguliar-Islas; Hendrik M. van Aken; Morten Andersen; Corey Archer; Maureen Auro; Hein J. de Baar; Oliver Baars; Alex R. Baker; Karel Bakker; Chandranath Basak; Mark Baskaran; Nicholas R. Bates; Dorothea Bauch; Pieter van Beek; Melanie K. Behrens; Erin Black; Katrin Bluhm; Laurent Bopp; Heather Bouman; Katlin Bowman; Johann Bown; Philip Boyd; Marie Boye; Edward A. Boyle; Pierre Branellec; Luke Bridgestock; Guillaume Brissebrat; Thomas Browning; Kenneth W. Bruland; Hans-Jürgen Brumsack; Mark Brzezinski; Clifton S. Buck; Kristen N. Buck; Ken Buesseler; Abby Bull; Edward Butler; Pinghe Cai; Patricia Cámara Mor; Damien Cardinal; Craig Carlson; Gonzalo Carrasco; Núria Casacuberta; Karen L. Casciotti; Maxi Castrillejo; Elena Chamizo; Rosie Chance; Matthew A. Charette; Joaquin E. Chaves; Hai Cheng; Fanny Chever; Marcus Christl; Thomas M. Church; Ivia Closset; Albert Colman; Tim M. Conway; Daniel Cossa; Peter Croot; Jay T. Cullen; Gregory A. Cutter; Chris Daniels; Frank Dehairs; Feifei Deng; Huong Thi Dieu; Brian Duggan; Gabriel Dulaquais; Cynthia Dumousseaud; Yolanda Echegoyen-Sanz; R. Lawrence Edwards; Michael Ellwood; Eberhard Fahrbach; Jessica N. Fitzsimmons; A. Russell Flegal; Martin Q. Fleisher; Tina van de Flierdt; Martin Frank; Jana Friedrich; Francois Fripiat; Henning Fröllje; Stephen J.G. Galer; Toshitaka Gamo; Raja S. Ganeshram; Jordi Garcia-Orellana; Ester Garcia-Solsona; Melanie Gault-Ringold; Ejin George; Loes J.A. Gerringa; Melissa Gilbert; Jose M. Godoy; Steven L. Goldstein; Santiago R. Gonzalez; Karen Grissom; Chad Hammerschmidt; Alison Hartman; Christel S. Hassler; Ed C. Hathorne; Mariko Hatta; Nicholas Hawco; Christopher T. Hayes; Lars-Eric Heimbürger; Josh Helgoe; Maija Heller; Gideon M. Henderson; Paul B. Henderson; Steven van Heuven; Peng Ho; Tristan J. Horner; Yu-Te Hsieh; Kuo-Fang Huang; Matthew P. Humphreys; Kenji Isshiki; Jeremy E. Jacquot; David J. Janssen; William J. Jenkins; Seth John; Elizabeth M. Jones; Janice L. Jones; David C. Kadko; Rick Kayser; Timothy C. Kenna; Roulin Khondoker; Taejin Kim; Lauren Kipp; Jessica K. Klar; Maarten Klunder; Sven Kretschmer; Yuichiro Kumamoto; Patrick Laan; Marie Labatut; Francois Lacan; Phoebe J. Lam; Myriam Lambelet; Carl H. Lamborg; Frédéric A.C. Le Moigne; Emilie Le Roy; Oliver J. Lechtenfeld; Jong-Mi Lee; Pascale Lherminier; Susan Little; Mercedes López-Lora; Yanbin Lu; Pere Masque; Edward Mawji; Charles R. Mcclain; Christopher Measures; Sanjin Mehic; Jan-Lukas Menzel Barraqueta; Pier van der Merwe; Rob Middag; Sebastian Mieruch; Angela Milne; Tomoharu Minami; James W. Moffett; Gwenaelle Moncoiffe; Willard S. Moore; Paul J. Morris; Peter L. Morton; Yuzuru Nakaguchi; Noriko Nakayama; John Niedermiller; Jun Nishioka; Akira Nishiuchi; Abigail Noble; Hajime Obata; Sven Ober; Daniel C. Ohnemus; Jan van Ooijen; Jeanette O'Sullivan; Stephanie Owens; Katharina Pahnke; Maxence Paul; Frank Pavia; Leopoldo D. Pena; Brian Peters; Frederic Planchon; Helene Planquette; Catherine Pradoux; Viena Puigcorbé; Paul Quay; Fabien Queroue; Amandine Radic; S. Rauschenberg; Mark Rehkämper; Robert Rember; Tomas Remenyi; Joseph A. Resing; Joerg Rickli; Sylvain Rigaud; Micha J.A. Rijkenberg; Stephen Rintoul; Laura F. Robinson; Montserrat Roca-Martí; Valenti Rodellas; Tobias Roeske; John M. Rolison; Mark Rosenberg; Saeed Roshan; Michiel M. Rutgers van der Loeff; Evgenia Ryabenko; Mak A. Saito; Lesley A. Salt; Virginie Sanial; Geraldine Sarthou; Christina Schallenberg; Ursula Schauer; Howie Scher; Christian Schlosser; Bernhard Schnetger; Peter Scott; Peter N. Sedwick; Igor Semiletov; Rachel Shelley; Robert M. Sherrell; Alan M. Shiller; Daniel M. Sigman; Sunil Kumar Singh; Hans A. Slagter; Emma Slater; William M. Smethie; Helen Snaith; Yoshiki Sohrin; Bettina Sohst; Jeroen E. Sonke; Sabrina Speich; Reiner Steinfeldt; Gillian Stewart; Torben Stichel; Claudine H. Stirling; Johnny Stutsman; Gretchen J. Swarr; James H. Swift; Alexander Thomas; Kay Thorne; Claire P. Till; Ralph Till; Ashley T. Townsend; Emily Townsend; Robyn Tuerena; Benjamin S. Twining; Derek Vance; Sue Velazquez; Celia Venchiarutti; Maria Villa-Alfageme; Sebastian M. Vivancos; Antje H.L. Voelker; Bronwyn Wake; Mark J. Warner; Ros Watson; Evaline van Weerlee; M. Alexandra Weigand; Yishai Weinstein; Dominik Weiss; Andreas Wisotzki; E. Malcolm S. Woodward; Jingfeng Wu; Yingzhe Wu; Kathrin Wuttig; Neil Wyatt; Yang Xiang; Ruifang C. Xie; Zichen Xue; Hisayuki Yoshikawa; Jing Zhang; Pu Zhang; Ye Zhao; Linjie Zheng; Xin-Yuan Zheng; Moritz Zieringer; Louise A. Zimmer; Patrizia Ziveri; Patricia Zunino; Cheryl Zurbrick
    Chemical Geology Elsevier B.V. 493 (20) 210 - 223 0009-2541 2018 
    The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2017 consists of two parts: (1) a compilation of digital data for more than 450 TEIs as well as standard hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing an on-line atlas that includes more than 590 section plots and 130 animated 3D scenes. The digital data are provided in several formats, including ASCII, Excel spreadsheet, netCDF, and Ocean Data View collection. Users can download the full data packages or make their own custom selections with a new on-line data extraction service. In addition to the actual data values, the IDP2017 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering and for statistical analysis. Metadata about data originators, analytical methods and original publications related to the data are linked in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2017 as section plots and rotating 3D scenes. The basin-wide 3D scenes combine data from many cruises and provide quick overviews of large-scale tracer distributions. These 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of tracer plumes near ocean margins or along ridges. The IDP2017 is the result of a truly international effort involving 326 researchers from 25 countries. This publication provides the critical reference for unpublished data, as well as for studies that make use of a large cross-section of data from the IDP2017. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González.
  • NAKAGUCHI Yuzuru; TAKAYAMA Shintaro; SANO Itaru
    Science and Technology 近畿大学理工学総合研究所 29 (29) 33 - 41 0916-2054 2017 
    Atmospheric samples were collected from March to June in 2014. Major ionic constituent (Na+ , NH4+ , K+ , Mg2+ , Ca2+, F- , Cl- , NO3- ,SO42-) , PM2.5 and PMc were observed. Asian Dust storm event were observed from May 28 to June 1 during this sampling period. The concentrations of F-, NO3- , K+, NH4+, Mg2+, Ca2+ in coarse fraction were increased during Asian Dust storm event. The concentrations of SO42- , NH4+, K+ were increased during Asian Dust storm event. The high correlation was recognized between Na+ and Cl- in the coarse fraction. The high correlations were recognized between SO42-, NH4+, K+, Ca2+ and PM2.5.
  • MATSUI Kazuaki; YOKOYAMA Yuichi; KAMEI Kunpei; NAKAGUCHI Yuzuru; EGUCHI Mitsuru; TANIGUCHI Akito; TAKEHARA Kohsei; FUMOTO Takayuki
    Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) Japan Society of Civil Engineers 73 (3) 134 - 142 2017 [Refereed]
     
     We explored the impact of combined sewer overflow (CSO) on the water quality of an urban river. We characterized the bacterial community of the Higashiyokobori-gawa waterway using next-generation DNA sequencing (Illumina Miseq). We examined bacterial 16S rRNA gene amplicons during rainfall periods. When rainfall exceeded 4 mm/h at our experimental site on the waterway, the bacterial community composition in the river water exhibited transient changes attributable to the CSO. The bacterial community composition in the waterway differed greatly from those in sewage, suggesting that the CSO had been diluted with bulk rainwater prior to discharge into the river. After a newly constructed stormwater storage pipe called Heisei-no-Taikougesui was commissioned, we found no changes in the bacterial community in river water even when rainfall exceeded 8 mm/h. This indicates that the storage pipe effectively prevented CSO discharge into the waterway. We suggest that bacterial community composition analysis is useful when evaluating/monitoring water quality.
  • NAKAGUCHI Yuzuru; HIROTA Akiko
    Science and Technology 近畿大学理工学総合研究所 28 (28) 1 - 11 0916-2054 2016 
    [Abstract]The origin of particulate matter which collected from the Indian Ocean and the Antarctic Ocean was clarified by individual particle analysis. Iron-rich particle which carried from land was observed at the surface in all sampling stations. Aluminum-dominant and Al-Si particles were observed at ER-5, 8 and 10 in the Indian Ocean sampling stations. These results confirmed that these particles were land origin such as aluminosilicate. A lot of silica dominant particles were observed at ER-14 in the Antarctic Ocean station. The SEM image of these particulate matter suggested that these particles were originated from diatom. The number of biogenic particles which exist at the surface has decreased with increase of depth.
  • NAKAGUCHI Yuzuru; IKEDA Yoshinori; HAMAYA Shin; ASAKURA Tomoya
    Chikyukagaku The Geochemical Society of Japan 50 (3) 227 - 241 0386-4073 2016 [Refereed]
     

    High pH values of 9.65 and 10.1 were observed in the Amano River, Osaka Prefecture in 2013 and 2015. On the other hand, the high pH values were not recorded in 2014. This basification was observed under conditions of high water temperature and high dissolved oxygen concentration. From the results of pH, dissolved oxygen, nitrate+nitrite, phosphate and total alkalinity, we confirmed that this basification might be due to decrease of carbon dioxide by photosynthesis in the Amano River. The changes of pH value in the river water might be affect the speciation of trace metals. Concentrations of dissolved species of aluminum, chromium and copper were increased with increase of pH value, while those of dissolved species of nickel and zinc were decreased with increase of pH value. From the positive correlation between the relative fluorescent intensity of dissolved organic matter and the concentrations of nickel and zinc we confirmed that these elements might be dissolved as metal-fulvic acid complex within the observed pH range.

  • Tomoharu Minami; Wataru Konagaya; Linjie Zheng; Shotaro Takano; Masanobu Sasaki; Rena Murata; Yuzuru Nakaguchi; Yoshiki Sohrin
    ANALYTICA CHIMICA ACTA ELSEVIER SCIENCE BV 854 183 - 190 0003-2670 2015/01 [Refereed]
     
    A novel automated off-line preconcentration system for trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in seawater was developed by improving a commercially available solid-phase extraction system SPE-100 (Hiranuma Sangyo). The utilized chelating resin was NOBIAS Chelate-PA1 (Hitachi High-Technologies) with ethylenediaminetriacetic acid and iminodiacetic acid functional groups. Parts of the 8-way valve made of alumina and zirconia in the original SPE-100 system were replaced with parts made of polychlorotrifluoroethylene in order to reduce contamination of trace metals. The eluent pass was altered for the back flush elution of trace metals. We optimized the cleaning procedures for the chelating resin column and flow lines of the preconcentration system, and developed a preconcentration procedure, which required less labor and led to a superior performance compared to manual preconcentration (Sohrin et al. [5]). The nine trace metals were simultaneously and quantitatively preconcentrated from similar to 120 g of seawater, eluted with similar to 15 g of 1 M HNO3, and determined by HR-ICP-MS using the calibration curve method. The single-step preconcentration removed more than 99.998% of Na, K, Mg, Ca, and Sr from seawater. The procedural blanks and detection limits were lower than the lowest concentrations in seawater for Mn, Ni, Cu, and Pb, while they were as low as the lowest concentrations in seawater for Al, Fe, Co, Zn, and Cd. The accuracy and precision of this method were confirmed by the analysis of reference seawater samples(CASS-5, NASS-5, GEOTRACESGS, and GD) and seawater samples for vertical distribution in the western North Pacific Ocean. (C) 2014 Elsevier B.V. All rights reserved.
  • NAKAGUCHI Yuzuru; FUJIWARA Tukasa; MAEDA Koouhei; TAKEDA Koichi; SANO Itaru
    Science and Technology 近畿大学理工学総合研究所 27 (27) 65 - 70 0916-2054 2015 
    [Abstract] In recent years, the cross-boundary air pollution from the eastern Asian continent to Japan Island becomes serious problem. The grasp of the concentration of pollutant adsorbed Asian dust particle and the clarification of the origin are important. The stable lead isotope ratios are one of possible tool for the clarification of the origin. In this study, the atmospheric aerosol samples were collected from March to May in 2012 over the Higashiosaka city. The lead isotopes (^206Pb, ^207Pb and ^208Pb) were analyzed by ICP-MS, and PM_2.5 was also analyzed. As a result, the lead concentrations in the aerosol samples were increased during the Asian Dust event. A significant, positive correlation was recognized between the lead concentrations and PM_2.5. The results of lead isotope ratio show that the various origins of atmospheric aerosols over the Higashiosaka city exist.
  • Nakaguchi Yuzuru; Ikeda Yoshinori; Hamaya Shin; Takayama Shintaro; Asakura Tomoya
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 61 112 - 112 2014 
    大阪府下を流下する天野川で夏季にpHが上昇する現象が観測された。2013年8月に連続観測した結果pHは最大9.65を示した。都市河川が塩基化するメカニズムの解明を目的に研究を行った。
  • Oku Natsumi; Takeda Kouichi; Jing Zhang; Sohrin Yoshiki; Nakaguchi Yuzuru
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 61 201 - 201 2014 
    白鳳丸KH-10-02次研究航海の際に採取したエアロゾル試料を使用し、日本海洋上の大気エアロゾルに含まれる生体活性微量金属とイオン成分についての分析を行い、日本海洋上における化学成分の分布とその起源の解明を目的とした。また分析結果から日本海への生体活性微量金属の乾性沈着量を見積もった。
  • MUKAI Sonoyo; SANO Itaru; NAKATA Makiko; NAKAGUCHI Yuzuru; IGUCHI Nobukazu; YASUMOTO Masayoshi; N.HOLBEN Brent
    Earozoru Kenkyu Japan Association of Aerosol Science and Technology 29 (1) s125 - s132 0912-2834 2014 
    Aerosol retrieval work from satellite data is divided into three parts: satellite data analysis, aerosol modeling, and multiple light scattering simulations in the atmosphere modeling what is known as the radiative transfer problem. It is well known that the aerosol model has been developed using the accumulated measurements during more than ten years provided with the world-wide aerosol monitoring network (AERONET). The radiative transfer simulations incorporate the Rayleigh scattering by molecules and Mie scattering by aerosols in the atmosphere. Thus the aerosol properties are estimated by comparing satellite measurements with the numerical values of radiation simulations in the Earth-atmosphere model. It is reasonable to consider that the precise simulation of multiple light scattering processes is necessary, and requires a long computational time, especially for an optically thick atmosphere. Therefore, efficient algorithms for radiative transfer problems are indispensable to retrieve aerosols from space. It is shown here that dense aerosol events can be well simulated by a semi infinite radiative-transfer model. For an example, the air pollution event observed by Aqua/MODIS in June of 2010 over Beijing is interpreted based on the proposed aerosol models and the semi-infinite radiative transfer simulation code known as MSOS (Method of Successive Order of Scattering).
  • NAKAGUCHI Yuzuru; FUJIWARA Tukasa; TAKEDA Koichi; SANO Itaru
    Science and Technology 近畿大学理工学総合研究所 26 (26) 41 - 49 0916-2054 2014 
    [Abstract] Particulate samples were collected by air sampler buring the Asian dust storm events in March 2010 at Higashiosaka, Japan. The elemental composition of individual particles was determined by using a scanning electron microprobe equipped with an energy-dispersive X-ray analyzer (SEM-EDX). According to elemental compositions for below 2.5 μm(PM2.5), 85.4% of the particles in March 2010 were Si-rich . For the 2.5 to 10μm (PMc), 80.9% of the particles were also Si-rich. According to the detail classification of Si-rich particles, the composition of Si-rich particles of surface soil samples collected at Ulaanbaatar and Han Uul in Mongolia were similar to the particles samples collected at Higashiosaka. The origin of Asian dust storm particles collected at Higashiosaka might be transported from the Mongolian desert. The back trajectory analysis supported these results. The number of Asian dust storm particles below 2.5μm adsorbing sulfur oxides was increased from 2007 to 2010.
  • 海洋と大気のセレンの地球化学的研究
    中口 譲
    月刊海洋「海水の微量元素・同位体に関するGEOTRACES観測研究ー進捗と新たな展開ー 55 65 - 74 2014
  • Jun-ichiro Ishibashi; Takuroh Noguchi; Tomohiro Toki; Shunsuke Miyabe; Shosei Yamagami; Yuji Onishi; Toshiro Yamanaka; Yuka Yokoyama; Eriko Omori; Yoshio Takahashi; Kenta Hatada; Yuzuru Nakaguchi; Motoko Yshizaki; Uta Konno; Takazo Shibuya; Ken Takai; Fumio Inagaki; Shinsuke Kawagucci
    GEOCHEMICAL JOURNAL GEOCHEMICAL SOC JAPAN 48 (4) 357 - 369 0016-7002 2014 [Refereed]
     
    Two active hydrothermal fields, Jade and Hakurei fields have been discovered within the Izena Hole, a rectangular 6 km x 3 km shape depression located in the middle Okinawa Trough back arc basin. In both fields, intense hydrothermal activity is represented by venting of high-temperature fluid (>300 degrees C) and occurrence of sulfide/sulfate ore deposits. We collected hydrothermal fluids during dive expeditions of ROV Hyper Dolphin conducted in 2003, 2010 and 2011, in order to analyze both elemental and gas species. The geochemistry of high temperature hydrothermal fluids collected from the Jade and Hakurei fields is very similar to each other with exceptions in minor gas composition. Little temporal variation was observed in geochemistry of the high-temperature hydrothermal fluid of the Jade field over two decades, since a previous study carried out in 1989. These results suggest that these fluids are derived from a common fluid reservoir where fluid chemistry is basically controlled by fluid-mineral equilibria and gas species are dominantly contributed from the same magma. Venting of low temperature fluid (about 104 degrees C) was discovered in the distal part of the Jade field, which was named as the Biwako vent. Chemical composition of the Biwako vent fluid was distinctive from that of the high temperature fluid in the proximal part of the Jade field, and could not be explained by simple dilution or cooling. This intra-field chemical diversity could be caused by phase separation and segregation during fluid upwelling, based on relationships in concentrations of Cl and major cations. On the other hand, the chemical diversity recognized in minor gas composition between the Jade and Hakurei fields is in accordance with results from previous plume survey. Difference in concentrations of minor gases such as H-2, is attributed to contribution from thermal degradation of organic matter in the sediment, during fluid,upwelling.
  • Shinsuke Kawagucci; Junichi Miyazaki; Ryota Nakajima; Tatsuo Nozaki; Yutaro Takaya; Yasuhiro Kato; Takazo Shibuya; Uta Konno; Yuzuru Nakaguchi; Kenta Hatada; Hisako Hirayama; Katsunori Fujikura; Yasuo Furushima; Hiroyuki Yamamoto; Tomo-o Watsuji; Jun-ichiro Ishibashi; Ken Takai
    GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS AMER GEOPHYSICAL UNION 14 (11) 4774 - 4790 1525-2027 2013/11 [Refereed]
     
    The Integrated Ocean Drilling Program (IODP) Expedition 331 investigated the Iheya North hydrothermal field in the Okinawa Trough. Several post-drilling underwater vehicle investigations were conducted over 2 years to identify post-drilling changes in fluid discharge pattern, mineral deposition, and fluid chemistry. Drilling-induced high-temperature hydrothermal fluid vents were identified at deep holes not only near the naturally occurring NBC hydrothermal fluid vent (Site C0016) but also at the seafloor similar to 450 m distal to the NBC vent (Site C0014), where no hydrothermal fluid discharge was observed prior to drilling. A chimney structure at Hole C0016A grew rapidly at the NBC mound crest, where only small chimneys had been found before drilling. A drilling-induced diffuse hydrothermal flow region spread at Site C0014, and this area was newly colonized by the galatheid crab. From a fluid chemistry perspective, the post-drilling hydrothermal fluids were enriched in Cl relative to seawater, although this fluid chemistry was not observed during the 12 years prior to drilling. The Cl-enriched fluid reservoir underlying the subseafloor impermeable layers, observed by IODP Expedition 331, is likely source for the Cl-enriched fluids discharging from the post-drilling vents. The drilling-induced physical disturbance of subseafloor hydrogeological structures would release such fluids to the seafloor. In turn, the rapid chimney growth at the NBC mound crest may also be attributed to highly turbulent fluid flow with the enlarged artificial vent of Hole C0016A, which can contribute to the retention of the fluid-seawater mixture for a sufficiently long period to precipitate sulfide/sulfate minerals on the seafloor.
  • NAKAGUCHI Yuzuru; KABUKI Jyunya; MASUDA Harue; NAKAJO Takeshi
    Science and Technology 近畿大学理工学総合研究所 25 (25) 37 - 48 0916-2054 2013 
    [Abstract] There are few reports on the research on the rare earth element in natural water. The difficulties for the determination of REEs in natural water are due to the low concentration in natural water. However, remarkable development of commercial chelate resin column (HITACHI NOBIAS PA-1) enabled simultaneously concentrated separation of rare earth elements in natural water sample. In this study, the geochemical studies on the rare earth elements in the river around the Lake Biwa and Yodo River system by ICP-MS with the chelate resin column separation method.
  • 淀川水系における化学成分の広域分布に関する調査報告
    中口 譲; 益田晴恵; 中条武司; 山中康平; 里口保文
    大阪自然史博物館研究報告 67 45 - 81 2013
  • M. Nakata; S. Mukai; I. Sano; Y. Nakaguchi; B. N. Holben; N. Sugimoto
    REMOTE SENSING OF THE ATMOSPHERE, CLOUDS, AND PRECIPITATION IV SPIE-INT SOC OPTICAL ENGINEERING 8523 0277-786X 2012 [Refereed]
     
    It is known that local spatially and temporally resolved measurements of atmospheric aerosols in Asian urban city are meaningful since the aerosol distribution in East-Asia is complicated due to the increasing emissions of anthropogenic aerosols in association with economic growth and natural dust significantly varies with the seasons. In this work, we intend to show the spatial and temporal variation of atmospheric aerosols in East Asia, especially around AERONET/Osaka site and Dragon-Asia period, named "DRAGON-Osaka". AERONET (Aerosol Robotics Network) Osaka site was established in 2002 in the campus of Kinki University. Nowadays, LIDAR, PM2.5 / (10) measurements and others are available. The site data are useful for algorithm development of aerosol retrieval over busy city. However, human activities in this region also emit the huge amount of pollutions, thus it is needed to investigate the local distribution of aerosols in this region. In March 2012, to obtain maximum efficiency of DRAGON-Osaka, several Cimels are deployed at more sites as soon as possible. In order to investigate change of aerosol properties, PM-individual analysis is made with scanning electron microscope (SEM) coupled with energy dispersive X-ray analyzer (EDX). A componential analysis presents temporal variation of aerosol properties.
  • Fujiwara Tsukasa; Ozaki Kengo; Nakaguchi Yuzuru; Sano Itaru; Mukai Sonoyo
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 58 359 - 359 2011 
    Particulate sample were collected by dust sampler during the Asian dust storm events in March and May 2011 at Higashiosaka, Japan to research modification of the Asian dust during transportation.The elemental composition of individual particles was determined using a scanning electron microprobe equipped with an energy X-ray analyzer(SEM-EDX) .
  • Nishiuchi Akira; Nakaguchi Yuzuru; Takeuchi makoto
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 58 206 - 206 2011 
    The dissolved selenium exist three chemical form such as selenite (SeO3-), selenate (SeO42-) and organic selenide in the ocean. The significant relationship was observed between selenite and silicate by some investigation. These results confirmed that selenite released from the dissolution of the skeletal matter such as Diatom. In this study, the chemical speciation of selenium was carried out by using sea water samples which collected by the R/V Hakuho-Maru during KH-10-2 cruise. In addition, biogenic silica was also determined same samples for research of biogenic silica effect on selenium species.
  • Nakaguchi Yuzuru; Asatani Takuya; Hirota Akiko; Nishida Akiko; Minami Hideki; Yamada Yukako; Sohrin Yoshiki; Obata Hajime
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 58 159 - 159 2011 
    The vertical distribution of bioactive trace metals in the Indian Ocean was investigated by using thesea water samples which was collected during the cruise of R/V Hakuho maru KH-09-5. The individual particle analysis of suspended particle samples were investigated by SEM-EDX.
  • Kato Yoshihisa; Sakamoto Midori; Tanaka Minako; Yamada Yukako; Minami Hideki; Takeuchi Makoto; Nakaguchi Yuzuru
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 58 163 - 163 2011 
    The Hakuho Maru KH-09-5 cruise, authorized as the the international GEOTRACES Program, has been conducted during Nov. 2009 to Jan. 2010. We collected abyssal sediment cores, using a multiple corer, in the western Indian Ocean including the Antarctic Sea. The concentrations of biogenic constituents, opal, calcite and barite, in surface sediment increase with increasing biological production in the surface ocean. The upward diffusive fluxes of nutrients and dissolved barium at the sediment-water interface are estimated, basis on their diagenetic distributions.
  • NAKAGUCHI Yuzuru; FUYUNO Masashi; YAMANAKA Kouhei; MASUDA Harue; NAKAJO Takeshi
    Science and Technology 近畿大学理工学総合研究所 23 (23) 59 - 65 0916-2054 2011 
    [Abstract] Selenium was chemically specified at 90 stations in the Yodo River system. The concentration of total selenium ranged from 0.034 to 0.339 μg/L. These values were below the regulatory limit (10 μg/L). The concentrations of selenite, selenate and organic selenium in the Yodo River system ranged from 0.000 to 0.107μg/L, from 0.000 to 0.076 μg/L and 0.014 to 0.198 μg/L, respectively.
  • NAKAGUCHI Yuzuru; FUJITA Akinori; NAKAGAWA Yoko; SHITASHIMA Kiminori
    Bulletin of the Society of Sea Water Science, Japan The Society of Sea Water Science, Japan 64 (4) 217 - 224 0369-4550 2010/08 [Refereed]
     
    Suspended particles were collected at the water surface in the Western Tropical Pacific Ocean. The suspended particles at the water surface were classified into 16 types using individual particle analysis and a scanning electron microprobe equipped with an energy-dispersive X ray analyzer. Si-rich particles were dominant at St.2, 4, 6 and 7. S-rich particles were dominant at St.8. Both biogenic particles and terrigenous particles were observed at all sampling points. The proportion of biogenic particles and terrigenous particles was 15-39%, and 61-85%, respectively. The possibility of direct supplement of terrigenous particles for St. 2, 4, 7 and 8 is smaller than those for St.6. The contribution of the terrigenous material from the Tuvurvur volcano was one possible origin of the suspended particles at St.7 and 8.
  • Mitsuo Uematsu; Hiroshi Hattori; Tokuhiro Nakamura; Yasushi Narita; Jinyoung Jung; Kiyoshi Matsumoto; Yuzuru Nakaguchi; M. Dileep Kumar
    MARINE CHEMISTRY ELSEVIER SCIENCE BV 120 (1-4) 108 - 115 0304-4203 2010/06 
    Experiments conducted aboard the R/V Hakuho Maru (Cruise KH-02-3) in the autumn of 2002 were designed to study the pathways of atmospheric aerosol transport, selected trace elements and major ions composition of particles and quantify their dry deposition over the East China Sea. We determined the concentrations of trace elements Al, Mn, Pb, Se, and Zn and major ions Na(+), SO(4)(2-) and NO(3)(-) in aerosol particles. Aerosols were continuously collected in fine and coarse size fractions with a cut off at 2.5 mu m. Particle number densities (volumes) were determined in four size ranges between 0.1 and <0.5 mu m. High Al concentrations in the coarse mode fractions suggest continental origin of these aerosols. Weather charts revealed conducive meteorological conditions for northeastward air mass transports from the Asian continent. Back trajectory analysis results corroborated with the meteorological observations. Nss-SO(4)(2-), Mn, Pb, Se and Zn were more abundant in the fine than coarse mode fraction, but NO(3)(-) was associated with the latter. About three-fold higher Mn/Al ratio in fine mode than in coarse aerosols (0.042 vs. 0.015, respectively) and a strong correlation between non-crustal Mn and nss-SO(4)(2-) suggest that fine Mn originates from industrial sources. Similarly, non-crustal Pb and Zn in the fine fraction were again significantly correlated with nss-SO(4)(2-) indicating major contributions from anthropogenic activities. Our results highlight the fact that atmospheric pollutants from Asia, including heavy metals and major ions, are carried to the East China Sea even during non-dusty periods. It is necessary to obtain the atmospheric deposition fluxes, wet and dry, throughout the year both by periodic and continuous atmospheric measurements in order to find the biogeochemical significance of Asian aerosols to the East China Sea and North Pacific Ocean. (C) 2010 Elsevier B.V. All rights reserved.
  • NAKAGUCHI Yuzuru; FUJITA Akinori; NAKAGAWA Yoko; SHITASHIMA Kiminori
    Bulletin of the Society of Sea Water Science, Japan 日本海水学会 64 (2) 99 - 108 0369-4550 2010/04 [Refereed]
     
    西部熱帯太平洋における生体活性微量金属の鉛直分布傾向の報告
  • 中口 讓; 藤田 昭紀
    Bull. Soc. Sea Water Sci. Jpn. 日本海水学会 63 (4) 253 - 268 2009/08 [Refereed]
     
    淡青丸の研究航海にて日本海にて採取した海水試料中の生体活性微量金属の鉛直分布傾向を解明
  • YAMAGUCHI Kazuhiro; NAKAGUCHI Yuzuru; MUKAI Sonoyo
    Chikyukagaku The Geochemical Society of Japan 43 (3) 91 - 101 0386-4073 2009/07 [Refereed]
     
    Particulate samples were collected by dust sampler during the Asian dust storm events in May 2007 and March 2008 at Higashiosaka, Japan (34°39'N, 135°35'E) to research modification of the Asian dust during transportation. The elemental composition of individual particles was determined using a scanning electron microprobe equipped with an energy-dispersive X-ray analyzer (SEM-EDX). According to the elemental compositions of the 2.5 to 10 μm particles, 94.4% of the particles in the May 2007 samples were Si-rich. The March 2008 samples were also Si-rich but showed Ca- and Na-rich particles of 8.2% and 6.9%, respectively. Surface soil samples, collected at Saynshand and Han Uul, Mongolia, where are the ones of the recent possible Asian dust source areas, were also analyzed. The results were similar to those found in the samples collected at Higashiosaka. Of special note was the similarity found in the ratio of Si-Al particles. The number of Asian dust storm particles adsorbing sulfur oxides was especially high in 2008. This could be explained by influences from the industrial areas in China. Other explanations would include consideration of the relationships between the ratio of modified particles and particle size and humidity during transport.
  • Nakaguchi Yuzuru; Mitsuhashi Yasunobu; Kitahata Kenichi; Fujita Akinori; Sumiyoshi Ayako; Kawai Yasuko
    Science and technology 近畿大学理工学総合研究所 21 (21) 25 - 33 0916-2054 2009/02 
    東部熱帯および亜熱帯南太平洋のセレンの状態分析結果
  • Yuzuru Nakaguchi; Ken-ich Kitahata; Akinori Fujita
    Bull. Soc. Sea Water Sci. Jpn. 日本海水学会 63 (1) 39 - 48 0369-4550 2009/02 [Refereed]
     
    白鳳丸研究航海にて西部北太平洋にて採取した海水試料中のセレンのスペシエーションの鉛直分布。
  • Nakaguchi Yuzuru; Takeuchi Makoto; Fuyuno Masashi; Nishiuchi Akira
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 56 334 - 334 2009 
    海洋においてセレンは無機形、有機形で存在することが報告さえているが、有機形セレンの分子種については不明な点が多い。研究発表では深層のフルボ酸体セレンの分離定量法を検討し、海洋における濃度および分布を調査した結果を報告する。
  • 山口 和宏; 中口 譲; 向井 苑生
    日本地球化学会年会要旨集 日本地球化学会 56 218 - 218 2009 
    東大阪市は大阪府の東に位置し、主要幹線道路である中央環状線、近畿自動車道、阪神高速東線が南北東西に通り、ディーゼル排気粒子(DEP)による大気汚染が顕著な地域である。この地域では、毎年3月から5月にかけて中国大陸で発生した黄砂が頻繁に飛来する。先の調査により東大阪市に到達した黄砂は、複数の地域を起源としており、輸送途中で変質していることが示唆された。本研究においては2009年の黄砂時に大気エアロゾルを採取し、元素組成分析を元に起源の推定を行った。また人為起源硫黄酸化物の寄与率を推定し、黄砂時における増減を観測した。
  • GOTO Takao; YAMAGUCHI Kazuhiro; NAKAGUCHI Yuzuru
    Journal of Japan Society for Safety Enginennring Japan Soceiety for Safety Engineering 48 (3) 177 - 184 0570-4480 2009 [Refereed]
     
    化学工場跡地の揮発性有機化合物による大気汚染を調査した結果の報告
  • Yamaguchi Kazuhiro; Nakaguchi Yuzuru
    Abstracts of Annual Meeting of the Geochemical Society of Japan GEOCHEMICAL SOCIETY OF JAPAN 55 269 - 269 2008 
    東大阪市は大阪府の東に位置し、主要幹線道路である中央環状線、近畿自動車道、阪神高速東線が南北東西に通り、ディーゼル排気粒子(DEP)による大気汚染が顕著な地域である。この地域では、毎年4月から5月にかけて中国大陸で発生した黄砂が頻繁に飛来する。本研究においては2007、2008年の黄砂時に大気エアロゾルを採取し、黄砂の変質過程ならびに東大阪市の大気に与える影響を調査した。
  • NAGAO S.; SAKAMOTO Y.; TANAKA T.; NAKAGUCHI Y.; RAO R. R.
    Journal of Nuclear and Radiochemical Sciences The Japan Society of Nuclear and Radiochemical Sciences 8 (2) 127 - 131 1345-4749 2007/12 [Refereed]
     
    The association properties of Am and Pu with aquatic fulvic acid in a 0.01 M NaClO4 solution at pH 6-7 were studied on the basis of molecular size distribution. Seven fulvic acids (FA) were isolated from river, lake, and groundwater samples using XAD extraction technique. They were used for comparison of their effects on the association of Am and Pu. In the absence of FA, about 80% of Am and 75% of Pu were found to have molecular size greater than 450 nm (particulate forms). On the other hand, in the presence of FA, particulate forms of Am and Pu decreased with increasing FA concentration, and were negligible at the FA concentration of 10 mg/L. Both Am and Pu were associated mainly with aquatic FA having two size fractions of 30-10 kDa or less than 5 kDa. The differences between Am and Pu were rather small and the association patterns were divisible into two groups: size-selective and non-size-selective. Complexation of FA with Am and Pu was controlled by the amount of FA, the percentage, and characteristics of each size fraction of FA.
  • NAKAGUCHI Yuzuru; HAMADA Hiroshi; SUYAMA Yuki; SANO Itaru; MUKAI Sonoyo
    Chikyukagaku The Geochemical Society of Japan 41 (4) 155 - 163 0386-4073 2007/10 [Refereed]
     
    The particle samples over Higashiosaka were collected by personal air sampler during asian-dust storms in April of 2005 and 2006. The size and elemental composition of individual perticles were investigated by scanning electron microprobe equipped energy-dispersive X-ray analyzer. From the results of individual particle analysis of Asian dust storm particles, Si-rich particles occupied 76.0% in 2.5-10.0μm diameter particles and 93.0% in <2.5μm diameter particles in April of 2005. In April 2006, Si-rich particles occupied 97.0% in 2.5-10.0μm diameter particles and 99.7% in <2.5μm diameter particles. Anthropogenic sulfur contaminated particles without sea salt were occupied by 2.2% in 2.5-10.0μm diameter particles and 3.6% in <2.5μm diameter particles in April 2005, and those were occupied by 0.4% in 2.5-10.0μm diameter particles and 2.9% in less than 2.5μm diameter particles in April 2006. From these results we confirmed that the degree of adsorption of anthropogenic sulfur oxides on to Asian dust storm particles during transport process from China to Japan was small in 2005 and 2006 over Higashiosaka.
  • The accumulation rate and benthic fluxes for selenium in the marginal seas
    中口 讓; 北畑謙一; 南秀樹
    近畿大学理工学総合研究所研究報告 19 23 - 29 2007/02 
    縁辺海堆積物および間隙水中のセレンの状態分析の結果から、堆積物―底層水へのフラックスを見積もった。
  • Distribution of stable isotopes of particulate lead in the atmosphere in Osaka, Japan
    中口 讓; 的場幸裕; 清水敦; 山崎 秀夫; 藤野 治; 南 武志
    Science and technology 近畿大学理工学総合研究所 18 35 - 40 2006/02 
    東大阪市大気中で捕集した浮遊粒子中の鉛同位体の分布および変動についてまとめた結果
  • Sonoyo Mukai; Itaru Sano; Masayoshi Yasumoto; Yuzuru Nakaguchi
    Remote Sensing of Clouds and the Atmosphere X SPIE 2005/10
  • NAKAGUCHI Yuzuru; YAMAGUCHI Yoshitaka; NISHIMURA Takashi; HATANO Yoshiyuki; IMANAKA Masayo; ARII Yasuhiro
    Chikyukagaku The Geochemical Society of Japan 39 (4) 173 - 182 0386-4073 2005/09 [Refereed]
     
    In order to elucidate the behavior and the seasonal variation of eutrophication substances in the Yodo River system, the dissolved inorganic nitrogen compounds, dissolved inorganic phosphate, total dissolved nitrogen (TDN), total dissolved phosphate (TDP) and dissolved organic carbon (DOC) were periodically observed during March 2001 to February 2002. Concentrations of TDN and TDP were near doubled downstream from the confluence of tributaries, the Katsura and Kizu Rivers. However, that of DOC did not increase significantly in the same interval. These results suggested that the nitrogen and phosphorus compounds from the tributaries had much influence on the water pollution of the Yodo River system compared to those of the main stream. The loads per year of TDN, TDP and DOC from the Yodo River to Osaka Bay were calculated to be 8,370, 444 and 11,700 ton/yr, respectively.
  • HATTA Mariko; ZHANG Jing; SATAKE Hiroshi; ISHIZAKA Joji; NAKAGUCHI Yuzuru
    Chikyukagaku The Geochemical Society of Japan 39 (3) 157 - 164 0386-4073 2005/06 [Refereed]
     
    In Toyama prefecture, because of the steep slope from the mountains to the coast coupled with high precipitation, a large volume of river water flows into Toyama bay, and the submarine groundwater discharge (SGD) ranges widely on the steep continental shelf. However, the substance budget and its impacts to the coastal environment have not been previously studied. The purpose of this study is to clarify the water mass structure of Toyama bay and to estimate the fluxes of freshwater and its nutrients by using a box model. Using the T-S diagram it is clear that Toyama bay water is made up of coastal surface water, Tsushima Warm Current (TWO water and deep water (Japan Sea Proper Water). It demonstrates that the upper 200 m (Toyama Bay Shallow Water) is composed of high salinity water (TWC) and low salinity water derived from freshwater. The freshwater flux was calculated with a box model of the shallow water. The maximum SGD flux (2.3×108 m3month-1) was about 25% of the river water flux (9.1×108 m3month-1). And the nutrient fluxes via the SGD path were 55% (PO43-) and 133% (NO2- + NO3-) of the river values. Furthermore the possibility was suggested from the N to P cocentration ratios that SGD entered the Toyama bay water colum primarily in the depth range of 〜100-180 m.
  • NAKAGUCHI Yuzuru; YAMAGUCHI Yoshitaka; YAMADA Hiroaki; ZHANG Jing; SUZUKI Mai; KOYAMA Yuki; HAYASHI Kiyoshi
    Chikyukagaku The Geochemical Society of Japan 39 (3) 119 - 130 0386-4073 2005/03 [Refereed]
     
    Nitrite+nitrate, phosphate, silicic acid and dissolved organic carbon (DOC) in the submarine groundwater discharge (S.G.D.) and the bottom water (upper 10-50 cm from the bottom) in Toyama Bay were observed. The concentrations of nitrite+nitrate and silicic acid in S.G.D. were approximately 60 and 30 times, respectively, higher than those in the bottom water. Nitrite+nitrate, phosphate and silicic acid in groundwater under an alluvial fan of Katagai River and Kurobe River were also determined. The residence time for groundwater is estimated to be long due to the high silicic acid concentration. The ratio of silicic acid/nitrite+nitrate showed that the route and origin of S.G.D. from groundwater under an alluvial fan of Katagai River. The characteristics of DOC in S.G.D. were investigated by three-dimensional excitation emission matrix spectroscopy. The fluorescent peaks which derived from humic-like and tryptophan-like substances were recognized in the bottom water. The typical fluorescent peak could not be recognized in the S.G.D. have been reported. The flux of nitrite+nitrate, phosphate and silicic acid into Toyama Bay by S.G.D. were estimated to be 2,290±700, 22±20 and 22,900±10,400 ton/year, respectively.
  • Dissolved selenium species in the Sulu Sea, the South China Sea and the Celebes Sea
    Yuzuru Nakaguchi; Muneyasu Takei; Hiroshi Hattori; Yasuhiro Arii; Yoshitaka Yamaguchi
    Geochemical Journal 38 571 - 580 2004/05 [Refereed]
  • Yuzuru Nakaguchi; Yoshitaka Yamaguchi; Munehito Kimura; Hiroshi Hattori; Hiroyuki Tsubota
    Bull. Soc. Sea Water Sci. Jpn. 56 306 - 315 2003/08 [Refereed]
  • 山口善敬; 中口譲; 秦野善行; 荒木祥子; 今中麻幸代; 高柳和史; 坂見知子; 紀本岳志; 平木敬三
    日本海水学会誌 56 (1) 47 - 56 2002/01 [Refereed]
  • YAMAGUCHI Yoshitaka; NAKAGUCHI Yuzuru; KIMURA Munehito; HIRAKI Keizo
    Bulletin of the Society of Sea Water Science, Japan The Society of Sea Water Science, Japan 55 (6) 419 - 427 0369-4550 2001/12 [Refereed]
     
    Seawater samples were collected in the western North Pacific, the Indian Ocean (Andaman Sea and Bay of Bengal), the Sea of Japan and the Sea of Okhotsk to find levels of dissolved organic carbon (DOC) and to analyze the three-dimensional excitation emission matrix spectrum. The DOC concentrations bellow 1000 m depth showed significantly different distribution. In the Sea of Japan, the mean concentration of DOC below 1000 m was higher, but in the other regions it was approximately the same concentration range. Fluorescent organic matter such as marine humic-like substances constituted 5 to 15% of DOC in the surface layer and 20 to 37% in the deep layer. The results show characteristics of the ocean regions, such as the difference in the nature of dissolved organic matter (DOM) or the existence of different production and decomposition processes of DOM in each ocean region.
  • Hattori Hiroshi; Nakaguchi Yuzuru; Ueda Manabu
    Journal of the Faculty of Science and Technology, Kinki University Kinki University 37 (37) 15 - 22 0386-4928 2001/09 
    北太平洋中緯度域において溶存セレン種の分布を調査した。 その結果、 オホーツク海由来の北太平洋中層水 (NPIW) が各測点の 300 ~ 700 m 付近に流入することによってセレンの酸化分解状態に変化が現れることが明らかとなった。
  • Nakaguchi Yuzuru; Shintaku Hideaki; Nishimura Takashi
    Journal of the Faculty of Science and Technology, Kinki University Kinki University 37 (37) 37 - 40 0386-4928 2001/09 
    海水中の栄養塩元素を定量する際に、 最も重要である標準溶液ならびにそれらを作成する際に用いる試薬の純度の決定方法を検討した。 その結果、 イオン交換カラムを用いた純度決定法で硝酸カリウムは比較的定量的に精製できたが、 リン酸二水素カリウムはさらに純度の高い製品を用いなければならないことが分かった。
  • Takada Masaki; Hattori Hiroshi; Nakaguchi Yuzuru
    Journal of the Faculty of Science and Technology, Kinki University Kinki University 37 (37) 23 - 29 0386-4928 2001/09 
    北西太平洋海底堆積物中のセレンの初期続成挙動を調査した結果、 堆積物表層では Se が直上水へ溶出しているかもしくは Se への還元が起こっていることが分かった。 また、 還元的な環境へ移行すると Se や有機態セレンは、 有機物により固相へ除去され、 鉄・マンガン酸化物に吸着していたセレンが脱離しているのが確認できた。
  • Yamaguchi Yoshitaka; Nakaguchi Yuzuru; Kitada Mikio
    Journal of the Faculty of Science and Technology, Kinki University Kinki University 37 (37) 31 - 55 0386-4928 2001/09 
    北部北太平洋は冬期に活発な鉛直混合により、 深層水中の栄養塩を表層に供給し、 植物プランクトンの活動を支えていることが分かった。 さらに DOC の分布と植物プランクトンの活動には直接的な関係は認められなかった。
  • Yoshitaka Yamaguchi; Yuzuru Nakaguchi; Hiroshi Hattori; Munehito Kimura; Keizo Hiraki
    Geochemical Journal 35 355 - 364 2001/08 [Refereed]
  • Hiroshi Hattori; Yuzuru Nakaguchi; Munihito Kimura; Keizo Hiraki
    Bull. Soc. Sea Water Sci. Jpn. 55 175 - 182 2001/06 [Refereed]
  • 服部裕史; 中口 譲; 近藤祐一郎; 高田正貴; 平木敬三
    地球化学 35 151 - 158 2001/05 [Refereed]
  • HATTORI H; NAKAGUCHI Y; SAITO Y; HIRAKI K
    Bull. Soc. Sea Water Sci. Jap. 55 (5) 333 - 339 2001 [Refereed]
     
    2, 3 ジアミノナフタレン (DAN) 蛍光法と HPLC を併用することにより、 海水中の溶存セレン種を精度良く定量することが出来た。 この時の検出限界値は 0.1 pg/L であった。 また有機態セレンを定量する際は塩素イオン濃度の存在による定量値への干渉を起こさないことも種々の検討実験により明らかになった。
  • T Shirasaki; H Sakamoto; Y Nakaguchi; K Hiraki
    BUNSEKI KAGAKU JAPAN SOC ANALYTICAL CHEM 49 (3) 175 - 179 0525-1931 2000/03 [Refereed]
     
    An analytical method for the determination of molybdenum in water samples was developed by isotope-dilution/microwave induced plasma mass spectrometry. The optimum analytical scanning conditions of a microwave induced plasma mass spectrometer, the effect of the isobar ((RU)-R-98) concentration on the accuracy of the Mo-98/Mo-97 ratio measurements, the dependency of the molybdenum concentration in a water sample on the RSD of Mo-98/Mo-97 ratio measurements, and the effect of the matrix-element concentration on the Mo-98/Mo-97 ratio measurements were investigated by measuring the Mo-98/Mo-97 ratio. As a results, the RSD of the Mo-98/Mo-97 Patio measurements was able to be measured within 1.0% when the molybdenum concentration exceeded 10 mu g/l. Moreover, it was also noted that an 8-hydroxyquinoline extraction technique coupled with isotope dilution/microwave induced plasma mass spectrometry was useful for determining molybdenum in high-matrix samples. The proposed method was applied to the determination of molybdenum in Trace Elements in Water (NIST SRM 1643c, 1643d), Open Ocean Seawater (NRCC NASS-4), Nearshore Seawater (NRCC CASS-3). The analytical results were in good agreement with the certified values.
  • XN Dong; Y Nakaguchi; K Hiraki
    BUNSEKI KAGAKU JAPAN SOC ANALYTICAL CHEM 46 (10) 785 - 790 0525-1931 1997/10 [Refereed]
     
    A new mixed chemical modifier, rhodium nitrate-magnesium nitrate (RhNO3-MgNO3), has been applied to the determination of trace amounts of selenium in human hair samples by using graphite furnace AAS. The use of combined modifier allows a compromise of higher pyrolysis temperature in the detection of selenium. The ashing and atomization temperatures for selenium are 1000 degrees C and 2600 degrees C, respectively. A study of the mechanism found that this mixed modifier combined with selenium to form a new material, a Rh-Mg-Se alloy, on the surface of the furnace during the ashing stage. The addition of modifier, as a selenium retainer, considerably improved the selenium sensitivity and stability of the method. The selenium level in a certified reference material, ''NIES No. 5 Hair'', and a mixed human hair sample were determined by using the method. The obtained analytical result was in good agreement with the certified value. The relative standard deviation (RSD%) for selenium was within 7%. The detection limit (3 sigma) of the method was 0.08 ng Se for 10 mu l injection sample.
  • S Nagao; Y Suzuki; Y Nakaguchi; M Senoo; K Hiraki
    BUNSEKI KAGAKU JAPAN SOC ANALYTICAL CHEMISTRY 46 (5) 335 - 342 0525-1931 1997/05 [Refereed]
     
    Humic substances play an important role in the transport of trace metals and insoluble organic materials. They are also considered to be precursors of trihalomethane in aquatic environments. The direct measurement of humic substances was carried out with a three-dimensional fluorescence spectrophotometer after filtering natural-water samples through a GF/F glass fiber filter. Because the influence of the humic concentration, pH and ionic strength on the three-dimensional excitation emission matrix spectra is negligible, the proposed method can be directly applied to the characterization of humic substances in freshwater samples (humic concentration 0.5 similar to 10 mg l(-1), pH 6 similar to 9 and ionic strength <0.04 M) and sea-water samples (ionic strength 0.75 M). Humic substances in river, lake and pore water samples exhibit 2 similar to 3 peaks at excitation 305 similar to 340 nm/emission 415 similar to 440 nm and excitation 250 similar to 270 nm/emission 440 similar to 450 nm. These peak positions correspond to those of fulvic acids isolated from soil.
  • Y SUZUKI; T SHIRASKI; Y NAKAGUCHI; Y KOIKE; K HIRAKI
    BUNSEKI KAGAKU JAPAN SOC ANALYTICAL CHEM 43 (12) 1127 - 1132 0525-1931 1994/12 [Refereed]
     
    Preconcentration by 8-quinolinol (oxine) extraction to determine molybdenum concentration in natural water by ICP-AES is described. Selection of the organic solvent was investigated. The molybdenum-oxine complex was extracted quantitatively into nitrobenzene, which was directly introduced into the ICP. Interfering substances, such as iron and copper, were removed by shaking with 1 M HCl after the extraction. This method was applied to the determination of molybdenum in seawater. The effect of treating the samples with acids prior to extraction was studied. Organic forms of molybdenum and/or permolybdic acid may be present in natural waters.
  • Yuzuru Nakaguchi; Keizo Hiraki
    Geochemical Journal 27 367 - 374 1993/09 [Refereed]
  • Yuichi Koike; Yuzuru Nakaguchi; Keizo Hiraki; Terufumi Takeuchi; Tomoyoshi Kokubu; Takeshi Ishimaru
    Journal of Oceanography 49 641 - 656 1993/05 [Refereed]
  • Y KOIKE; Y NAKAGUCHI; K HIRAKI
    BUNSEKI KAGAKU JAPAN SOC ANALYTICAL CHEM 42 (5) 285 - 291 0525-1931 1993/05 [Refereed]
     
    The vertical distributions of Se(IV) and organic selenium in open sea are similar to those of nutrients. It was therefore considered that Se(IV) and organic selenium in sea water were supplied from the decomposition of marine biological material. In this study, marine planktons were used as biological material. Some pretreatment procedures were investigated for the chemical speciation of selenium in marine plankton samples. Selenium was determined by 2,3-diaminonaphthalene (DAN) fluorometry. The interference of coexistent fluorescent materials for the fluorescence spectrum of 4,5-piazselenol (Se-DAN complex) was effectively removed by back-extraction with concentrated nitric acid, followed by a wet-ashing method, and dilution with distilled water to 80 times the initial sample solution. The contents of selenium species in plankton body fluid changed with time. The sample pretreatment must therefore be carried out immediately after plankton thawing.
  • Tatsuo Aono; Yuzuru Nakaguchi; Keizo Hiraki
    Geochemical Journal 25 45 - 55 1991/04 [Refereed]
  • Tatsuo Aono; Yuzuru Nakaguchi; Keizo Hiraki; Takayuki Nagai
    Geochemical Journal 24 255 - 261 1990/08 [Refereed]
  • O FUJINO; M MATSUI; T NAGAHIRO; Y NAKAGUCHI; K HIRAKI
    NIPPON KAGAKU KAISHI CHEMICAL SOC JAPAN (2) 153 - 156 0369-4577 1988/02 [Refereed]
  • Keizo Hiraki; Yuzuru Nakaguchi; Michitaka Morita; Hideharu Kitamaki
    Analytical Sciences 2 561 - 566 1986/12 [Refereed]

Books etc

  • みんなでつくる淀川大図鑑 山と海をつなぐ生物多様性, 淀川の自然環境 淀川の水-プロジェクトY水質班の調査結果
    石田惣; 中条武司他; 中口 讓 (Joint work)大阪市立自然史博物館 2010/07 
    2007年から2009年にかけて行われた淀川水系広域調査研究プロジェクトY水質班の調査結果報告
  • 月刊海洋号外 「微量元素海洋学」事始-GEOTRACES計画-, 海洋のセレン-新たなスペシエーション-
    中口 讓; 冬野正史; 竹内誠 (Joint work)海洋出版株式会社 2010/01 
    海洋のセレンの分子種別分析法に関する最新のトピックスについて解説した。
  • ベーシック 機器分析化学
    市村彰男; 中口 讓; 河合潤; 紀本岳志; 文珠四郎秀昭 (Joint work)化学同人 2008 
    化学分析に汎用される機器分析法の原理、応用を記述した教科書
  • 月刊海洋号外 微量元素と同位体を用いた海洋の生物地球化学研究-GEOTRACES計画の動向と推進-, 海水-堆積物境界面におけるフラックス研究のための深海モノタリングランダーの開発
    中口 讓; 南秀樹; 許正憲 (Joint work)海洋出版株式会社 2006/09 
    海水-堆積物境界面におけるフラックス研究のための深海モニタリングランダーの現状と開発方法についての解説した。
  • 海洋の微量元素・同位体研究-GEOTRACES計画-, 海洋における懸濁粒子の化学組成と間隙水を経由する物質の拡散フラックス
    南秀樹; 中口 讓; 北畑謙一; 土井崇史; 小畑元; 丸尾雅啓; 加藤義久 (Joint work)海洋出版株式会社 2005/09 
    海洋における懸濁粒子の化学組成と堆積物から間隙水を通じて底層にもたらされる物質のフラックス
  • 海と湖の化学 微量元素で探る
    藤永太一郎; 中口 讓; 平木敬三; 宗林由樹; 一色健司 (Joint work)京都大学学術出版会 2005 
    海水中の化学成分でも特にセレンとアルミニウムの分布特性、分析についての記述を担当した。
  • Biogeochemical Processes and Ocean Flux in the Western Pacific
    Yuzuru Nakaguchi; Yuich Koike; Keizo Hiraki (ContributorChemical speciation of selenium in natural waters)Terra Scientific Publishing Company 1995
  • 各種分析手法におけるサンプリング・試料調製法と前処理技術 -原子吸光分析- 分担
    技術情報協会 1993
  • 分子種分画法を用いた海水中の有機態金属化合物の分布
    1991

Conference Activities & Talks

  • Study on the bioactive trace metals in the aerosol over the northern North Pacific and the East China Sea.  [Not invited]
    TUJI Naoki; TANIURA Ryou; OKU Natsumi; NAKAGUCHI Yuzuru
    The 65th meeting of Geochemical Society of Japan  2018/09
  • Study on improvement of water quality for Yamada pond.  [Not invited]
    NAKAGUCHI Yuzuru; SHIMAYA Hiroki; HONDA Sou; KOIKE Mami
    The meeting of Geochemical society of Japan  2018/09
  • Study on basifying river of Yodogawa river system  [Not invited]
    NAKAGUCHI Yuzuru; TUJI Naoki; GEHOU Kota
    第82回 日本陸水学会  2017/09
  • Distributions and atmospheric imput of bioactive trace metals in the East China Sea  [Not invited]
    NAKAGUCHI Yuzuru; IKEDA Yoshiniri; Oku Natsumi; TANIURA Ryo; TSUJISAKA Makoto; LINJIE Zheng; MINAMI Tomoharu; SOHRIN Yoshiki
    Goldshumidt 2017  2017/08
  • Study on basification of the Amano River  [Not invited]
    NAKAGUCHI Yuzuru; IKEDA Yoshinori; HAMAYA Shin; ASAKURA Tomoya
    The 63th meeting of the Geochemical Society of Japan  2016/09
  • Determination of selenium in sea water by hydride generation -ICPOES  [Not invited]
    NAKAGUCHI Yuzuru; FUKUDA Yuki; KOTERA Saya
    日本分析化学会 第77回討論会  2016/05
  • 天野川の塩基性化に関する研究  [Not invited]
    中口 譲; 池田善紀; 濱屋心; 朝倉智也
    2015年度 日本地球化学会年会  2015/09
  • 日本海における生物活性微量金属の分布および輪廻挙動に関する研究  [Not invited]
    鈴木博貴; 中西亮介; 坂本敦史; 下里 義泰; 中口譲; 南友晴; 宗林由樹
    2015年度 日本地球化学会年会  2015/09
  • 天野川の塩基性化に関する研究(1)  [Not invited]
    中口 譲; 池田善紀; 濱屋心; 高山真太郎; 朝倉知也
    2014年度 日本地球化学会年会  2014/09
  • 日本海洋上大気エアロゾル中の生体活性微量金属に関する研究  [Not invited]
    奥菜津美; 武田光市; 張勁; 宗林由樹; 中口譲
    2014年度 日本地球化学会年会  2014/09
  • The Atmospheric Input of Bioactive Trace Metals in the Japan Sea  [Not invited]
    NAKAGUCHI Yuzuru; TAKADA Koichi
    Asia Oceania Geosiences Society 2014  2014/07
  • 日本海における溶存態生物活性微量元素の分布(GEOTRACES JAPAN KH-10-2次航海  [Not invited]
    中口 譲; 坂本敦史; 宗林由樹
    2012年度 日本地球化学会年会  2012/09
  • 日本海における微量元素の経年比較  [Not invited]
    坂本敦史; 中口 譲; 宗林由樹; 下島公紀
    2012年度 日本地球化学会年会  2012/09
  • 西部北太平洋上大気エアロゾル中の化学組成分析  [Not invited]
    武田 光市; 中口 譲; 益田 晴恵; 張 勁
    2012年度 日本地球化学会年会  2012/09
  • Mercury concentrations in biological materials of Japan(1) =Mercury concentration in brown rice and tree frog in Japan  [Not invited]
    山崎 秀夫; 南 武志; 中口 讓; 小林大一郎; 中野好高; 古谷直樹
    第14回環境化学討論会  2005/06  大阪市  第14回環境化学討論会
     
    日本各地から集めた玄米及びアマガエル臓器の水銀濃度をサーベイした。本研究は平成16年度大学院高度化推進特別研究費によって実施された。
  • Selenium in the Japan Sea Proper Water  [Not invited]
    中口 讓; 服部裕史; 高田正貴; 植田学; 平木 敬三
    日本海洋学会春季大会 (東京)  2001/03  日本海洋学会春季大会 (東京)
     
    これまでにほとんど報告されていない日本海底層水中 (日本海固有水) における溶存セレンの分布・挙動を調査した。 その結果、 表層から底層水中に至るまでの循環像を把握することが出来た。

Works

  • 東京大学海洋研究所淡青丸KT03-9次研究航海
    2003
  • 洋上における大気・海洋化学成分in situ計測システムの開発研究
    1998
  • 東京大学海洋研究所白鳳丸KH98-3次研究航海
    1998
  • 東京大学海洋研究所白鳳丸KH96-5次研究航海
    1996
  • 紀伊半島の環境保全に関する研究(フィールドワーク)
    1994
  • 東京大学海洋研究所白鳳丸KH94-3次研究航海
    1994
  • 新エネルギー・産業技術総合開発機構委託業務「海洋中の炭素循環メカニズムの調査研究」白嶺丸NH94-1次研究航海
    1994
  • 紀伊半島の環境保全に関する研究(フィールドワーク)
    1993
  • 東京大学海洋研究所白鳳丸KH92-4次研究航海
    1992
  • 東京大学海洋研究所白鳳丸KH90-3次研究航海
    1990
  • 東京大学海洋研究所白鳳丸KH88-3次研究航海
    1988

MISC

Awards & Honors

  • 2023/04 Research Institute for Oceanochemistry Foundation 38th Marine Chemistry Academic Award
     Biogeochemical studies on trace essential elements 
    受賞者: Yuzuru Nakaguchi

Research Grants & Projects

  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2019/04 -2023/03 
    Author : 宗林 由樹; 高野 祥太朗; 鄭 臨潔; 中口 譲; 南 秀樹
     
    (1)生物活性微量金属の鉛直断面分布.北太平洋のCd, Ni, Zn, Cuの分布に関する論文を発表した.これは台湾のHo博士らとの共同研究である.日本海とオホーツク海におけるAl, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pbの分布に関する論文を発表した.南太平洋のAl, Mn, Co, Pbの分布についての論文を投稿した.KH-17-3北太平洋亜寒帯域航海の海水試料の分析を進めた. (2)Ni, Cu, Znの安定同位体比.亜寒帯北太平洋で採取された海水試料の分析を完了した.淡水試料中のNi, Cu, Znの安定同位体比についての論文を発表した.東シナ海の沈降粒子中Znの安定同位体比についての論文を発表した.東シナ海の海水中Ni, Cu, Znの安定同位体比についての論文を投稿した.後者二つは台湾のHo博士らとの共同研究である. (3)Mo, Wの安定同位体比.中新世後期アラビア海の堆積物中Mo, Wに基づき古海洋の酸化還元状態を復元する論文を発表した.これはインドのGurumurthy博士らとの共同研究である.海水中W同位体比の分析法を改良し,海水,河川水,雨水などの分析を進めた. (4) Pd, Pt, Auの分析法.キレート樹脂固相抽出とICP質量分析法に基づく自然水中Pd, Pt, Auの分析法の開発を進めた. (5)海洋断面分布と海洋堆積物の相互作用.KH-12-4航海において北太平洋ファンデフカ海嶺などで採取された堆積物試料を分析し,その解析を進めた.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2012/04 -2015/03 
    Author : SOHRIN Yoshiki; NAKAGUCHI Yuzuru; NORISUYE Kazuhiro; MINAMI Tomoharu; TAKANO Shotaro; ZHENG Linjie
     
    Ocean-sectional distribution of bioactive trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) has been studied in the Indian Ocean, Arctic Ocean, and other regions. A novel automated preconcentration system has been developed for one-step preconcentration of bioactive trace metals. A precise analytical method for copper stable isotope ratio in seawater has been developed to reveal distribution and cycling of copper stable isotopes in the Pacific, Indian, and Atlantic Ocean. In addition, we studied high-field strength elements (Zr, Hf, Nb, Ta, Mo, W), noble metals (Pd, Pt, Au), Se, Bi, and speciation. We also joined the R/V Hakuho-maru cruises of KH-12-4 in the subarctic North Pacific and of KH-14-6 from the North Pacific through the Antarctic to carry out clean sampling of seawater from surface to bottom.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2007 -2010 
    Author : GAMO Toshitaka; OBATA Hajime; AMAKAWA Hiroshi; SOHRIN Yoshiki; HASUMI Hiroyasu; OKAMURA Kei; ZHANG Jing; NAKAGUCHI Yuzuru; YAMADA Masatoshi; SHIRAIWA Yoshihiro; NORIKI Shinichiro; MINAMI Hideki; NISHIOKA Jun; SHITASHIMA Kiminori; KATO Yoshihisa; MINAGAWA Masao; MARUO Masahiro; OTOSAKA Shigeyoshi; NAKAYAMA Noriko; NAGAI Hisao; MURAYAMA Masafumi
     
    研究成果の概要(英文):As part of the international GEOTRACES (Global marine biogeochemical cycles of trace elements and their isotopes) program, we successfully conducted meridional research cruises in the Indian Ocean (from Arabian Sea to the Antarctic Ocean) and in the Japan Sea using the research vessel Hakuho Maru. We took clean seawater samples (total ~300 samples) for the measurement of GEOTRACES key paremeters(Fe,Al,Zn,Mn,Cd,Cu,δ^<15>N,δ^<13>C,^<230>Th,^<231>Pa, Pb isotopes,Nd isotopes), and their analyses are now ongoing in shorebased laboratories.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2006 -2008 
    Author : MUKAI Sonoyo; SANO Itaru; NAKAGUCHI Yusuzu; YASUMOTO Masayoshi; IGUCHI Nobukazu
     
    (1)NASA/AERONET放射計等による大気エアロゾル地上観測、(2)SPMのサンプリング計測と化学分析、(3)エアロゾル放射特性とSPM値の関係解析、(4)地上と衛星データの併合によるエアロゾルマップの導出等に関し、継続的に研究実績を挙げている. (5)2008年5月にNIESライダーネットワーク機器を設置し、(6)エアロゾルの発生から拡散までの解明、(7)総合的なデータ解析手法の実装、(8)モデルシミュレーションと実データの融合を実現した.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2004 -2005 
    Author : MUKAI Sonoyo; OKADA Yasuhiko; MIZOBUCHI Shoji; NAKAGUCHI Yuzuru
     
    Japanese observing satellite, called ADEOS (Advanced Earth Observing Satellite), carried POLDER (Polarization and Directionality of Earth Reflectance) and operated from November in 1996 to June in 1997. The successor ADEOS-2/POLDER worked from April to the end of October in 2003. This work shows that polarization information given by POLDER is useful to retrieve aerosols, especially over the land. Our retrieval algorithm for aerosols is based on the light scattering behavior of the atmospheric particles in the visible and near infrared wavelengths. The retrieved results are validated with ground based sun photometry. It is found from comparison between aerosol products derived from POLDER and POLDER-2 that aerosol loading increases from 1997 to 2003 over the East Asia. Furthermore, combination use of POLDER and GLI looks promising to improve the aerosol retrieval.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2002 -2004 
    Author : ETOH Takeharu; TAKEHARA Kohsei; NAKAGUCHI Yuzuru; KAJII Hironobou; TAKANO Yasuhide
     
    A.Development of Application Technologies of PTV to Natural Water Bodies (1)An efficient technology was developed to detect tracer particles for PTV on surfaces of natural water bodies, such as rivers, lakes, etc. The tracers can be separated by a combination of discriminant analysis of color images and duration analysis, which removes candidates of tracer particle images disappearing within two seconds. (2)The technology was applied to measurement of the surface flow field of Yodo river, etc. The flow field was also measured with ADCP (Acoustic Doppler Current Profiler) carried by a boat. The results nicely agreed with each other. (3)A technique for simultaneous measurement of wave and flow under wind waves was developed. (4)In parallel, seasonal variations of chemical components in Yodo river were measured, especially on Nitrogen and Phosphor. B.Development of Air Samplers Carried along a Tether of a Balloon and/or a Kite (1)Air samplers attached to a tether of a balloon was developed. Several samplers can be attached to a tether to collect air samples at various heights. (2)In a weak-wind condition, the samplers were tested. A dust dome was detected as expected, which showed the maximum concentration of dusts at about 50m from the ground, and less concentration at the ground and at 100m. The dust dome was also visualized by a camera mounted on the balloon. C.Relevant Research Contributions An infrared video camera was introduced by the financial support of this project. The camera was applied to other researches relating to infrared image analyses, resulting in the following contributions : (1)Application of infrared video cameras to reduce traffic accidents at the corners and intersections of roads in night. (2)Applications to various research projects on temperature environment around human bodies.
  • 大気中の微細粒子状金属化合物の研究
    Date (from‐to) : 2000
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1997 -1998 
    Author : 中口 譲
     
    平成10年度は陸起源物質の指標となるラミン酸、フルボ酸を地下水より濃縮、精製し、その蛍光特性を調査した。また蛍光性腐植物質の外洋における挙動を溶存有機炭素(DOC)、栄養塩類、クロロライル類の分布と比較し、調査した。 1. 地下水腐植物質の蛍光特性:地下水腐植物質は千葉県茂原市より採取した試料より、分離、精製したものを用いた。まず、市販フミン酸、地下水フミン酸、地下水ラルボ酸の3次元励起・蛍光スペクトルを測定したところ、それぞれ、励起波長(EX.)280nm/蛍光波長(Em.)500nmおよびEx.450nm/Em.530nm、Ex.245nm/Em.395nmおよびEx.295nm/Em.405nm、Ex.235nm/Em.420nmおよびEx.315nm/Em.410nmに蛍光ピークが認められた。市販フミン酸と地下水フミン酸のスペクトル形状を比較すると、ピーク位置は異なり、腐植物質の形成過程の相異すなわち土壌有機物の組成の違いを反映していると考えられた。また地下水フミン酸、フルボ酸のIRスペクトルの結果からは3500cm^<-1>および1400cm^<-1>に見られるアルコール性および芳香族性-〇H基の振動に由来するシグナルの相異が認められ、このことがフミン酸、フルボ酸の蛍光特性に反映しているものと考えられた。この結果と昨年報告した淀河川水の蛍光特性をもとに2.の外洋域における蛍光物質の特性を調査した。 2. 外洋における蛍光物質の分布挙動:北西太平洋上にてCTD-CMSを用い海水試料を採取した。試料はガラス繊維ろ紙にてろ過し、ろ液について、3次元励起蛍光スペクトルを測定した。その結果、試料中にはEx.260nm/Em.380〜420nm(Peak A)およびEx.275nm/Em.340nm(Peak B)に蛍光ピークが認められた。また蛍光強度の鉛直分布は表層で低く、水深が深くなるに連れて増大する傾向を示し、DOCやクロロフィルの分布とは異なっており、この起源が陸に由来するのではなく、海洋に由来すると考えたほうが妥当であるとの知見を得た。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1996 -1996 
    Author : 平木 敬三; 中口 譲
     
    3次元励起・蛍光スペクトル分析法により、汚染の度合いなど特性の異なる3つの河川、すなわち比較的汚染の度合いが小さい和歌山県田辺市の会津川、琵琶湖を水源とし桂川、木津川などと合流する淀川そして汚染度は日本一と言われている大和川中の蛍光性物質について調査を行った。この中で淀川については1995年12月及び1996年5月に採取した試料については3ヶ所に蛍光強度ピークが認められた。またこの蛍光強度は上流から下流に行くに従い増加する傾向を示し、桂川、木津川と合流した地点からその蛍光強度は著しく増大し、人為的負荷の可能性を示唆した。また同時に溶存有機炭素、硝酸十亜硝酸、アンモニア、りん酸、ケイ酸、アミノ酸、炭水化物、クロロフィルaを定量したが、溶存有機炭素および栄養塩類濃度とは高い相関性を示し、蛍光性物質がある種の有機物から成っている可能性が示唆された。また、5月に採取した試料についてはアミノ酸および炭水化物濃度と蛍光強度の間に負の相関性が認められ蛍光物質の構成成分の中にアミノ酸、炭水化物が含まれている可能性を示した。蛍光強度ピークについてはこれまでの研究結果と比較すると、1つはタンパク様物質と2つはフルボ酸様物質のピーク位置とほぼ一致した。また蛍光物質の起源に関しては下流域においては河川泥中の間隙水(直上水を含む)中の蛍光ピークとほぼ一致しその起源として河川泥からの寄与が考えられた。一方、和歌山県の会津川については淀川同様溶存有機炭素との間に高い相関性が認められた。従って蛍光性物質は何らかの有機物から構成されており、この詳細な解明は陸源物質の沿岸海域から外洋域への輸送過程を解明する上で重要と考えられる。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1994 -1994 
    Author : 平木 敬三; 中口 譲
     
    1.高速液体クロマトグラフィーによるセレンの迅速定量法の確立 海洋や湖沼において植物プランクトンの増殖制限が顕著に認められるセレンについてHPLCによる定量法を検討確立した。まず基本操作としては試料中のセレンの原子価ををSe(IV)とした後、2,3-ジアミノナフタレン(DAN)と反応させセレン-DAN錯体(4,5-ベンゾピアセレノール)を生成させる。これをシクロヘキサン相に抽出したものを0.2μm孔経のPTFEろ紙でろ過した後、試料100μlをHPLCに注入し、ナカライテスク製のシリカゲル充填カラムCosmosil 5SL(粒径5μm;150mm×4.6mm i.d.)により分離した後、試料を蛍光検出器に導き定量を行うこととした。流量、カラム温度などの諸条件を検討しHPLCによるセレンの高感度定量法を確立した。なお結果については平成7年5月に行われる日本分析化学会討論会で発表する。 2.天然水試料からのセレンの濃縮法の検討 先に確立したHPLC法を天然水試料中のセレンの定量に適用するため濃縮法の検討を行った。濃縮にはSep-PakカートリツジNH2を用いることとし、条件検討を行った。その結果試料溶液をpH2に調整し12ccの充填カラムに流しセレンを吸着させる、次に3Nアンモニア水で溶離した結果、約94%という高い回収率が得られた。濃縮操作については今後も継続し検討を行う。 3.天然水中における微量元素濃度とプランクトンの異常増殖の関係 平成6年7月下旬より8月上旬にかけて和歌山県浦神湾において、栄養塩、微量元素、多項目プロファイラーによる定点の日週観測および48時間の連続観測を行った。結果については現在解析中であり、平成7年度の日本海洋学会等で公表の予定である。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1990 -1990 
    Author : 平木 敬三; 中口 譲
     
    1.大気試料の捕集法の検討 基本的には大気試料を液化捕集することとし、液体窒素を冷媒とし、その中にガラス管を設置し試料を液化捕集した。大気試料の捕集管への導入は、捕集管内での液化凝縮による減圧により行なわれる。この際、試料中の水蒸気が導入部分で氷結し流入を妨げるので、あらかじめ、氷ー塩化ナトリウム水溶液中にコンデンサ-を沈め取り除くことにした。この捕集装置により100リットル前後の試料を5〜6時間で捕集できた。液化試料は再気化させ濃硝酸に吸収させ、原子吸光法により鉛、コバルト、銅、マンガン、モリブデンなどを定量した。しかし、この方法によりさらに多量の試料を捕集することは難しいので、窒素、酸素など主要成分と目的成分を分離濃縮捕集する検討を合せて行なった。液体窒素中に捕集管の先端部分だけを浸し、その後部に吸引用に捕集管の上端部まで液体窒素に沈めその部分に酸素、窒素などの低沸点物質を液化捕集し、その際の体積減少により試料を吸引させる。高沸点の目的成分はこの方法で効率的に捕集できた。その際の液化捕集条件を詳細に検討した結果、捕集効率の低下は多量の試料捕集により、液化されない成分が徐々に集積され、吸引管内の圧を高めることによることが明らかになった。しかし、1〜2m^3の試料から目的成分を捕集定量することを可能とした。 2.揮発性金属化合物の起源の解明 大気試料の捕集実験の実施中、河川などの表面から目的成分が多量に見出されたり、大気中の目的成分中、セレン、銅、コバルトなど生体必須成分が著しい季節変動を示すことから、河川底質中などの微生物によるものと考え、インキュベ-ション中の揮発性物質の分析を行ない、興味ある結果を得た。これらの成果は本年度の分析化学討論会及び北京で開催される第4回Asian Chemical Congressにて発表する。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1988 -1988 
    Author : 平木 敬三; 中口 譲; 藤野 治
     
    1. セレン 海水等天然水中のセレンの約50%を有機態セレンが占め、さらに琵琶湖においては有機態セレンの高濃度帯にクロロフィルaの高濃度帯が出現し、その鉛直分布の特徴から生物による影響を強く受けていることが示唆された。そこでこのような結果が全海洋的に普遍的なものであるかを調査する目的で、太平洋のロイヒ海山周辺、アラスカ湾およびベーリング海においてセレン(IV)、セレン(VI)有機態セレンの鉛直分布を調査した。その結果、セレン(IV)は明らかに生物制限元素型の鉛直分布を示し、PO_4-PやNO_3-Nなどの栄養塩と極めて類似した鉛直分布を示すのに対し、他のセレン種ではそのような特徴は見出せなかった。さらに有機態セレンについては特にアミノ酸態セレン化合物の分画分析法を確立し、上記の試料に適用した結果ベーリング海の深層においてアミノ酸態セレンの増加傾向が認められた。 2.モリブデン 海水中のモリブデンについては比較的多く研究が行われているが、その溶存種のほとんとが酸素酸アニオンであるとされている。しかし極微量ながらそれ以外の分子種の存在が指摘されており、このことを確かめるため、より簡便で正確な定量法(ニトロベンゼン抽出-ICP発光分析法)の確立を行った。このとき試料を硫硝酸により加熱処理した場合と、しない場合との分析値の間に分析誤差を越えた差が生じる。この原因としては海水中に存在する過酸化水素による過モリブデン酸の生成が考えられた。この過モリブデン酸の鉛直分布は有光層下限までて消滅し、過酸化水素の存在領域に一致することが明らかとなり、モリブデンは微生物との直接的な影響以外、生物等を起源とする有機化合物の光分解の過程で生成する物質にも影響されることがわかった。 3.その他 カドミウム、希土類元素の原子スペクトル分析法およびリン酸態リンのICP発光分析法の確立も行なった。
  • 海洋における有機物及び富栄養化関連物質の研究
  • 天然水中の微量元素の状態別分析
  • Study on trace elements in the atmospheric aerosols
  • Study on the analysis of dissolved organic carbon in Seawater
  • Speciation of trace element in natural water


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