Researcher Database

Toshifumi Igarashi
Faculty of Engineering Sustainable Resources Engineering Geoenvironmental Engineering
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Engineering Sustainable Resources Engineering Geoenvironmental Engineering

Job Title

  • Professor

URL

J-Global ID

Research Interests

  • 地球システム   水質   地盤環境   Earth system(5603)   Water quality(5206)   Underground environment(5203)   

Research Areas

  • Energy / Earth resource engineering, energy science
  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Civil engineering (environmental systems)
  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Geotechnical engineering

Association Memberships

  • JAPAN SOCIETY ON WATER ENVIRONMENT   日本応用地質学会   JAPAN SOCIETY OF MATERIAL CYCLES AND WASTE MANAGEMENT   北海道環境保全技術協会   地盤工学会   土木学会   北海道環境地質研究会   日本原子力学会   資源・素材学会   日本地下水学会   Japan Society of Engineering Geology   Japan Society of Waste Management Experts   Hokkaido Association for the Preservation of the Environmenta through Technology   The Japanese Geotechnical Society   Japan Socoety of Civil Engineering   Japanese Association of Groundwater Hydrology   Atomic Energy Society of Japan   The Mining and Materials Processing Institute of Japan   

Research Activities

Published Papers

  • Carlos A. Marove, Pawit Tangviroon, Carlito B. Tabelin, Toshifumi Igarashi
    JOURNAL OF AFRICAN EARTH SCIENCES 168 1464-343X 2020/08 [Refereed][Not invited]
     
    Large-scale coal mining is being carried out in Tete province, Mozambique. This area is also being planned to become a large coal fired power production hub serving electricity to neighboring countries in southern Africa. Thus, huge amounts of coal will be burned, resulting in the generation of a large quantity of coal ash. High concentrations of hazardous elements are often released from coal and coal ash causing negative impacts to human health and the environment. Therefore, it is important to understand the possibility of hazardous elements leaching. Aqueous batch leaching experiments under ambient conditions were conducted using six coal samples and their ash. Most of the coal leached very low concentrations of hazardous elements. However, an absence of carbonate minerals gave rise to higher acidity levels. This resulted in elevated leaching concentrations of manganese and iron, regardless of their contents. Burning coal resulted in higher contents of hazardous elements in the ash. However, leaching concentrations of most of the elements from the ash samples were still lower than the environmental standards. Chromium and manganese were enriched in slightly acidic leachates regardless of their contents while higher arsenic than the permitted level was leached from the ash containing the highest arsenic content that generated neutral pH leachate. These findings highlight a possibility of hazardous elements contamination from Mozambican coal and coal ash. Therefore, the storage of coal and disposal of coal wastes and ash in Tete Province should be done carefully and monitored to avoid the contamination in the region.
  • Marthias Silwamba, Mayumi Ito, Naoki Hiroyoshi, Carlito Baltazar Tabelin, Tomoki Fukushima, Ilhwan Park, Sanghee Jeon, Toshifumi Igarashi, Tsutomu Sato, Imasiku Nyambe, Meki Chirwa, Kawawa Banda, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    Journal of Environmental Chemical Engineering 8 (4) 104197 - 104197 2213-3437 2020/08 [Refereed][Not invited]
  • Pawit Tangviroon, Yuka Endo, Ryota Fujinaka, Masato Kobayashi, Toshifumi Igarashi, Takahiro Yamamoto
    WATER AIR AND SOIL POLLUTION 231 (6) 0049-6979 2020/05 [Refereed][Not invited]
     
    Cementitious materials are commonly used to reinforce the bearing capacity of silty soils. However, there is very little data about how changes in arsenic (As) leaching from silty soils caused by the addition of cementitious materials. Therefore, batch leaching tests were conducted using As-bearing silty soil under different pH conditions. The pH was adjusted by changing the amount of slag cement added or the concentration of sodium hydroxide. This allows us to evaluate the effects of cement on As leaching. In addition, two different additives were applied to reduce As migration. The results show that high concentration of calcium ion (Ca2+) in leachates of soil-cement mixture has a significant effect in reducing the mobility of As even under hyperalkaline pH conditions. Arsenic immobilized by Ca2+ was observed in two patterns. The first mechanism was the help of Ca2+ to reduce the negative electrical potential on the surface of (hydr)oxide minerals under high pH conditions, thereby reducing the mobility of As by adsorption and coagulation of fresh precipitates of Fe and Al hydroxides. The second was the precipitation of calcium carbonate. This precipitate either directly adsorb/co-precipitate As or lower the concentration of strong competing ion, silica, both of which reduced the As mobility. When Ca- or Mg-based additive was added to the silty soil-cement mixture, As concentration in the leachate decreased. These findings are useful in developing sustainable soil-cement reinforcement techniques to avoid contamination.
  • Toshifumi Igarashi, Pepe Salgado Herrera, Hiroyuki Uchiyama, Hiroko Miyamae, Nobuyoshi Iyatomi, Koichi Hashimoto, Carlito Baltazar Tabelin
    SCIENCE OF THE TOTAL ENVIRONMENT 715 0048-9697 2020/05 [Refereed][Not invited]
     
    Acid mine drainage (AMD) or acid rock drainage (ARD), the most notorious environmental problem in many mines and underground construction sites, is generally managed using lime neutralization. This approach is effective but unsustainable in the long term, so we introduced the two-step neutralization ferrite-formation process in our previous works as an alternative. However, several important issues related to this new approach- the partitioning of hazardous elements during treatment, stability of generated sludges, and influence of coexisting ions-remains unclear. In this study, real AMD containing zinc (Zn), copper (Cu) and arsenic (As) was treated using a laboratory-type continuous ferrite process flow setup. Partitioning of hazardous elements in the two sludges was elucidated by X-ray fluorescence spectroscopy (XRF) and X-ray absorption spectroscopy (XAS) while the stability of sludges was determined by standard leaching experiments. The bulk of Cu and As species (both As(III) and As(V) based on XANES spectra) were partitioned in the first sludge while similar to 64% of Zn was associated with the ferrite sludge. In terms of stability, both sludges were relatively inert and released only minute amounts of Zn, Cu and As, all of which were below the Japanese environmental standards. The roles played by two of the most ubiquitous coexisting ions in AMD on ferritization-dissolved silica (Si) and aluminum ion (Al3+)-were also elucidated using 10 synthetic AMDs. Between the two, dissolved Si exhibited stron- ger adverse effects on ferritization than Al3+. At dissolved Si above 4 mg/L, Si-O-Fe surface complex formation on amorphous Fe-precipitates or Fe-oxide precursor minerals became extensive, which protected these phases from the dissolution-transformation reactions required to form strongly magnetic magnesioferrite and magnetite. These results suggest that the flexibility and applicability of this new AMD treatment approach could be improved by controlling the dissolved Si concentration prior to the ferrite formation step. (C) 2020 Elsevier B.V. All rights reserved.
  • Marthias Silwamba, Mayumi Ito, Naoki Hiroyoshi, Carlito Baltazar Tabelin, Ryota Hashizume, Tomoki Fukushima, Ilhwan Park, Sanghee Jeon, Toshifumi Igarashi, Tsutomu Sato, Meki Chirwa, Kawawa Banda, Imasiku Nyambe, Hokuto Nakata, Shouta Nakayama, Mayumi Ishizuka
    METALS 10 (4) 531 - 531 2020/04 [Refereed][Not invited]
     
    Zinc plant leach residues (ZPLRs) contain significant amounts of metal compounds of lead (Pb), zinc (Zn), iron (Fe), etc., hence, they are considered as a secondary source of metals. On the other hand, ZPLRs are regarded as hazardous materials because they contain heavy metals that pollute the environment. Resources and environmental concerns of ZPLRs were addressed in this study by removing/recovering Pb and Zn using a concurrent dissolution and cementation technique. To cement the dissolved Pb and Zn in leaching pulp, zero-valent aluminum (ZVAl) was added during ZPLRs leaching in the hydrochloric (HCl)-sodium chloride (NaCl) solution. The resulting cemented metals were agglomerated and separated by sieving. Lead removal increased with increasing both NaCl and HCl concentrations. However, when ZVAl was added, significant Pb removal was achieved at a low concentration. Zinc was not cemented out of the pulp using ZVAl and its recovery from ZPLRs was dependent on the HCl concentration only. By applying a concurrent dissolution and cementation technique, both Pb and Zn were removed using a low concentration of NaCl, and most importantly Pb-the most toxic metal in ZPLRs-was captured and separated before the solid-liquid separation, hence, eliminating the need for extensive washing of the generated residues to remove the inherent residual solution.
  • Shingo Tomiyama, Toshifumi Igarashi, Carlito Baltazar Tabelin, Pawit Tangviroon, Hiroyuki Ii
    JOURNAL OF CONTAMINANT HYDROLOGY 230 103617 - 103617 0169-7722 2020/03 [Refereed][Not invited]
     
    This study evaluated the assumption that back-filled excavated areas of old mine workings can be modeled as porous media, where groundwater flow is governed by Darcy's law. The Yatani mine, located in Yamagata Prefecture, Japan, was selected for this study because several mining methods were used during its operation and detailed drawings of the excavated areas of the mine are available. The model was calibrated using combinations of hydraulic conductivities (k), with the best-matched case being selected by comparing calculated and measured AMD fluxes. Modeled AMD fluxes along the drainage tunnel (-2 L level) were consistent with measured data when the excavated areas were considered to be porous media with a specific hydraulic conductivity, and the presence of faults and permeability were taken into account. The model also successfully predicted the increasing trend of AMD flux from the shaft to adit mouth. In the numerical model, the back-filled excavated areas were assumed to behave as porous media, which was shown to be a valid assumption in this mine. The model demonstrated that back-filling the excavated areas and drainage tunnel with low permeability materials could reduce the flux of Zn in AMD by up to 61%.
  • Dang Thuong Huyen, Tabelin Carlito Baltazar, Huynh Minh Thuan, Dang Hai Dang, Phan Thi Truong, Vongphuthone Banthasith, Kobayashi Masato, Igarashi Toshifumi
    CHEMOSPHERE 233 512 - 523 0045-6535 2019/10 [Refereed][Not invited]
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Meki Chirwa, Kawawa Banda, Imasiku Nyambe, Shouta Nakayama, Hokuto Nakata, Mayumi Ishizuka
    Chemosphere 228 17 - 25 0045-6535 2019/08 [Refereed][Not invited]
     
    Environmental impacts resulting from historic lead and zinc mining in Kabwe, Zambia affect human health due to the dust generated from the mine waste that contains lead, a known hazardous pollutant. We employed microbially induced calcium carbonate precipitation (MICP), an alternative capping method, to prevent dust generation and reduce the mobility of contaminants. Pb-resistant Oceanobacillus profundus KBZ 1-3 and O. profundus KBZ 2-5 isolated from Kabwe were used to biocement the sand that would act as a cover to prevent dust and water infiltration. Sand biocemented by KBZ 1-3 and KBZ 2-5 had maximum unconfined compressive strength values of 3.2 MPa and 5.5 MPa, respectively. Additionally, biocemented sand exhibited reduced water permeability values of 9.6 × 10-8 m/s and 8.9 × 10-8 m/s for O. profundus KBZ 1-3 and KBZ 2-5, respectively, which could potentially limit the entrance of water and oxygen into the dump, hence reducing the leaching of heavy metals. We propose that these isolates represent an option for bioremediating contaminated waste by preventing both metallic dust from becoming airborne and rainwater from infiltrating into the waste. O. profundus KBZ 1-3 and O. profundus KBZ 2-5 isolated form Kabwe represent a novel species that has, for the first time, been applied in a bioremediation study.
  • Shingo Tomiyama, Toshifumi Igarashi, Carlito Baltazar Tabelin, Pawit Tangviroon, Hiroyuki Ii
    JOURNAL OF CONTAMINANT HYDROLOGY 225 103502 - 103502 0169-7722 2019/08 [Refereed][Not invited]
     
    This paper describes the geochemistry of groundwater and its flow system in the closed Yatani mine in southern Yamagata Prefecture, Japan. The mine is located in a sulfide deposit containing pyrite and has been generating acid mine drainage (AMD). The study was intended to elucidate the formation of AMD and its flow patterns using geological, hydrological, geochemical, and isotopic techniques. The results indicate that AMD is formed by the interaction of groundwater with sulfide minerals, sand slime, and tailings back-filled into excavated mine areas. Groundwater recharge areas were identified on the mountain slope at an elevation of similar to 900 m. The formation of AMD in the drifts and shaft was more extensive than that in the deeper drainage levels. Principal component analysis was applied to the hydrogeochemical data to identify the causes of AMD formation. The first, second, and third principal components reveal that the increased ion concentrations in mine drainage are a result of water mineral reactions in excavated mine areas, the contribution of groundwater in deep reductive environments, and isotopic fractionation during precipitation, respectively. A promising method of reducing AMD formation is to prevent contact between dissolved oxygen and sulfide minerals by increasing the drainage level or by filling the shallow underground excavated area with cementitious materials.
  • Zinc and Lead Biosorption by Oceanobacillus Profundus Kbz 3-2: a Bacterial Strain Resistant to Metals Isolated from Metal polluted Soils in Kabwe, Zambia
    Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Meki Chirwa, Kawawa Banda, Imasiku Nyambe, Shouta Nakayama, Mayumi Ishizuka
    Proceedings of the 14th Asian Congress on Biotechnology (ACB2019) 2019/07 [Refereed][Not invited]
  • Khoeurn Kimleang, Sakaguchi Asumi, Tomiyama Shingo, Igarashi Toshifumi
    JOURNAL OF GEOCHEMICAL EXPLORATION 201 1 - 12 0375-6742 2019/06 [Refereed][Not invited]
  • Wilson Mwandira, Kazunori Nakashima, Satoru Kawasaki, Mayumi Ito, Tsutomu Sato, Toshifumi Igarashi, Kawawa Banda, Meki Chirwa, Imasiku Nyambe, Shouta Nakayama, Mayumi Ishizuka
    ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH 26 (15) 15653 - 15664 0944-1344 2019/05 [Refereed][Not invited]
     
    Biocementation of hazardous waste is used in reducing the mobility of contaminants, but studies on evaluating its efficacy have not been well documented. Therefore, to evaluate the efficacy of this method, physicochemical factors affecting stabilized hazardous products of in situ microbially induced calcium carbonate precipitation (MICP) were determined. The strength and leach resistance were investigated using the bacterium Pararhodobacter sp. Pb-contaminated kiln slag (KS) and leach plant residue (LPR) collected from Kabwe, Zambia, were investigated. Biocemented KS and KS/LPR had leachate Pb concentrations below the detection limit of <0.001mg/L, resisted slaking, and had maximum unconfined compressive strengths of 8MPa for KS and 4MPa for KS/LPR. Furthermore, biocemented KS and KS/LPR exhibited lower water absorption coefficient values, which could potentially reduce the water transportation of Pb2+. The results of this study show that MICP can reduce Pb2+ mobility in mine wastes. The improved physicochemical properties of the biocemented materials, therefore, indicates that this technique is an effective tool in stabilizing hazardous mine wastes and, consequently, preventing water and soil contamination.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Gregory White, Tatsuo Nishizawa, Toshifumi Igarashi, Toyoharu Nawa, Jize Mao
    CONSTRUCTION AND BUILDING MATERIALS 200 713 - 755 0950-0618 2019/03 [Refereed][Not invited]
     
    Researchers dealing with pavements and experts on materials have been increasingly focused on the structural strength of the pavement materials without paying sufficient attention to the environment and cultural norms. In the 21st century, the concept of pavement design and rehabilitation needs to be modified owing to new requirements such as the additional structural loads derived from the climate change, environmental challenges, social requirements, and aging population. Therefore, the concept of post-modern pavement (PMP) was proposed to address the structural, sustainability, and sociopsychological requirements. In this review of the state-of-the-art, the potential of the interlocking concrete block pavement (ICBP) was evaluated based on its laboratory and field structural performance, sustainability, and social acceptance as a PMP in Japan. Therefore, the relevant literature in English and Japanese, including journals, conference proceedings, technical reports, books, and theses, over a span of 47 years (1971-2018), were studied. It was found that the structural and functional performances of the ICBP in different facilities were satisfying. Furthermore, owing to its waste material use, less noise emission, air purifying characteristics, and heat island reduction, the environmental performance of ICBP was in harmony with sustainable practices. In addition, pavements users, both able and differently abled, rated the ICBP as a more appropriate pavement system owing to its physical appearance, serviceability, aesthetic features, lower heat island effect, rapid maintenance, and positive psychologic effects after earthquake and tsunami events. As a result, the ICBP can be recommended as a PMP for the design and development of resilient transportation infrastructure assets in Japan. (C) 2018 Elsevier Ltd. All rights reserved.
  • Khoeurn Kimleang, Sasaki Asuka, Tomiyama Shingo, Igarashi Toshifumi
    MINE WATER AND THE ENVIRONMENT 38 (1) 119 - 129 1025-9112 2019/03 [Refereed][Not invited]
  • Tamamura Shuji, Murakami Takuma, Aramaki Noritaka, Ueno Akio, Tamazawa Satoshi, Badrul Alam A. K. M, Haq Shofa Rijalul, Igarashi Toshifumi, Aoyama Hideo, Yamaguchi Shinji, Kaneko Katsuhiko
    INTERNATIONAL JOURNAL OF COAL GEOLOGY 202 14 - 26 0166-5162 2019/02/01 [Refereed][Not invited]
  • Tabelin Carlito Baltazar, Igarashi Toshifumi, Villacorte-Tabelin Mylah, Park Ilhwan, Opiso Einstine M, Ito Mayumi, Hiroyoshi Naoki
    SCIENCE OF THE TOTAL ENVIRONMENT 645 1522 - 1553 0048-9697 2018/12/15 [Refereed][Not invited]
  • Haq Shofa Rijalul, Tamamura Shuji, Ueno Akio, Tamazawa Satoshi, Aramaki Noritaka, Murakami Takuma, Alam A, K. M. Badrul, Igarashi Toshifumi, Kaneko Katsuhiko
    INTERNATIONAL JOURNAL OF COAL GEOLOGY 197 66 - 73 0166-5162 2018/09/01 [Refereed][Not invited]
  • Ali Jamshidi, Gregory White, Kiyofumi Kurumisawa, Toyoharu Nawa, Toshifumi Igarashi, Meor Othman Hamzah
    JOURNAL OF CLEANER PRODUCTION 189 635 - 646 0959-6526 2018/07 [Refereed][Not invited]
     
    In this study, the effects of the warm-mix asphalt additive content, asphalt type, and various mixing and test temperatures on the creep stiffness and cumulative micro-strain of asphalt mixtures were analyzed. In addition, the correlation between the rheological properties of the warm mix binders and mixtures were evaluated. Furthermore, a new methodology, namely, the hypotenuse length and sustainable angle method, was proposed to analyze the structural environmental performance of the warm mix technology. The results showed that there was a close relationship between the properties of the asphalt binders and mixtures for various binder types and ageing states. Furthermore, the results indicated that this new methodology could be used by pavement and environment engineers to determine whether an asphalt mix is consistent with environmental regulations well as satisfying the structural performance requirements. (C) 2018 Elsevier Ltd. All rights reserved.
  • Khy Eam Eang, Toshifumi Igarashi, Ryota Fujinaga, Megumi Kondo, Carlito Baltazar Tabelin
    Environmental Monitoring and Assessment 190 (4) 1573-2959 2018/04/01 [Refereed][Not invited]
     
    Groundwater flow and its geochemical evolution in mines are important not only in the study of contaminant migration but also in the effective planning of excavation. The effects of groundwater on the stability of rock slopes and other mine constructions especially in limestone quarries are crucial because calcite, the major mineral component of limestone, is moderately soluble in water. In this study, evolution of groundwater in a limestone quarry located in Chichibu city was monitored to understand the geochemical processes occurring within the rock strata of the quarry and changes in the chemistry of groundwater, which suggests zones of deformations that may affect the stability of rock slopes. There are three distinct geological formations in the quarry: limestone layer, interbedded layer of limestone and slaty greenstone, and slaty greenstone layer as basement rock. Although the hydrochemical facies of all groundwater samples were Ca-HCO3 type water, changes in the geochemical properties of groundwater from the three geological formations were observed. In particular, significant changes in the chemical properties of several groundwater samples along the interbedded layer were observed, which could be attributed to the mixing of groundwater from the limestone and slaty greenstone layers. On the rainy day, the concentrations of Ca2+ and HCO3 − in the groundwater fluctuated notably, and the groundwater flowing along the interbedded layer was dominated by groundwater from the limestone layer. These suggest that groundwater along the interbedded layer may affect the stability of rock slopes.
  • Shofa Rijalul Haq, Shuji Tamamura, Toshifumi Igarashi, Katsuhiko Kaneko
    International Journal of Coal Geology 185 1 - 11 0166-5162 2018/01/02 [Refereed][Not invited]
     
    The reaction of coal with hydrogen peroxide (H2O2) has been reported to accelerate the microbial transformation of coal into biogenic methane. To understand the mechanism of the increased bioavailability of coal as a result of H2O2 treatment, we investigated the effects of H2O2 reaction on humic substances of lignite by characterizing their structure and relative abundance. The H2O2-treated lignite, referred to as lignite-H2O2, was also examined in column experiments to confirm the increases in lignite solubilization and organic acids as indicators of enhanced bioavailability. The results showed that the alkali-soluble carbon content of lignite increased by 4.9 times (from 0.4 to 2.1 g C) after H2O2 treatment, and the humic acid (HA) content of this fraction increased by 7.7 times (from 0.2 to 1.5 g C). Previously, the enhanced solubility of lignite after H2O2 treatment was attributed to increased hydrophilicity of the lignite. However, we propose that this phenomenon is actually caused by chemical fragmentation (i.e., β-fragmentation) involving a radical reaction. In the column experiments, lignite treated with H2O2 showed higher dissolved organic carbon (up to 84.8 mg/L) and organic acid (up to 18.9 mg/L for acetic acid, and up to 19.9 mg/L for formic acid) concentrations than lignite without treatment. These results indicate the potential to optimize CH4 production from microbially enhanced coalbed methane operations using H2O2.
  • Khy Eam Eang, Toshifumi Igarashi, Megumi Kondo, Tsurugi Nakatani, Carlito Baltazar Tabelin, Ryota Fujinaga
    International Journal of Mining Science and Technology 28 (6) 849 - 857 2095-2686 2018 [Refereed][Not invited]
     
    Water-rock interaction and groundwater mixing are important phenomena in understanding hydrogeological systems and the stability of rock slopes especially those consisting largely of moderately water-soluble minerals like calcite. In this study, the hydrogeological and geochemical evolutions of groundwater in a limestone quarry composed of three strata: limestone layer (covering), interbedded layer under the covering layer, and slaty greenstone layer (basement) were investigated. Water-rock interaction in the open-pit limestone quarry was evaluated using PHREEQC, while hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to classify and identify water sources responsible for possible groundwater mixing within rock layers. In addition, Geochemist's Workbench was applied to estimate the mixing fractions to clarify sensitive zones that may affect rock slope stability. The results showed that the changes in Ca2+ and HCO3 − concentrations of several groundwater samples along the interbedded layer could be attributed to mixing groundwater from the limestone layer and that from slaty greenstone layer. Based on the HCA and PCA results, groundwaters were classified into several types depending on their origin: (1) groundwater from the limestone layer (LO), (2) mixed groundwater flowing along the interbedded layer (e.g., groundwater samples L-7, L-11, S-3 and S-4), and (3) groundwater originating from the slaty greenstone layer (SO). The mixing fractions of 41% LO: 59% SO, 64% LO: 36% SO, 43% LO: 57% SO and 25% LO: 75% SO on the normal days corresponded to groundwaters L-7, L-11, S-3 and S-4, respectively, while the mixing fractions of groundwaters L-7 and L-11 (61% LO: 39% SO and 93% LO: 7% SO, respectively) on rainy days became the majority of groundwater originating from the limestone layer. These indicate that groundwater along the interbedded layer significantly affected the stability of rock slopes by enlarging multi-breaking zones in the layer through calcite dissolution and inducing high water pressure, tension cracks and potential sliding plane along this layer particularly during intense rainfall episodes.
  • Shuji Tamamura, Kazuya Miyakawa, Noritaka Aramaki, Toshifumi Igarashi, Katsuhiko Kaneko
    Groundwater 56 (1) 118 - 130 1745-6584 2018/01/01 [Refereed][Not invited]
     
    Gas-saturated groundwater forms bubbles when brought to atmospheric pressure, preventing precise determination of its in situ dissolved gas concentrations. To overcome this problem, a modeling approach called the atmospheric sampling method is suggested here to recover the in situ dissolved gas concentrations of groundwater collected ex situ under atmospheric conditions at the Horonobe Underground Research Laboratory, Japan. The results from this method were compared with results measured at the same locations using two special techniques, the sealed sampler and pre-evacuated vial methods, that have been developed to collect groundwater under its in situ conditions. In gas-saturated groundwater cases, dissolved methane and inorganic carbon concentrations derived using the atmospheric sampling method were mostly within ±4 and ±10%, respectively, of values from the sealed sampler and pre-evacuated vial methods. In gas-unsaturated groundwater, however, the atmospheric sampling method overestimated the in situ dissolved methane concentrations, because the groundwater pressure at which bubbles appear (Pcritical) was overestimated. The atmospheric sampling method is recommended for use where gas-saturated groundwater can be collected only ex situ under atmospheric conditions.
  • P. Tangviroon, T. Igarashi
    Water, Air, and Soil Pollution 228 (12) 1573-2932 2017/12/01 [Refereed][Not invited]
     
    Large volumes of excavated rock are produced as a result of road and railway tunnel construction in Hokkaido, Japan. Due to the geological condition of this region, these rocks have often undergone hydrothermal alterations, causing them to contain elevated amounts of hazardous elements including arsenic (As). Therefore, these excavated rocks are potentially hazardous waste, and proper disposal methods are required. In this article, performance of unsaturated river sediment on immobilizing As from hydrothermally altered rock is evaluated using laboratory column experiments and Hydrus-1D. The results reveal that the river sediment significantly reduces As migration. Arsenic retarded by river sediment was observed in three patterns. The first was an adsorption onto minerals originally contained in the river sediment. The next pattern was a combination of reduction of As generation by oxidation of As bearing-minerals, irreversible adsorption, and adsorption onto newly precipitated Fe oxy-hydroxide/oxide. The last pattern led to a further depletion of As leached from the rock layer due to a shift in the majority of the As generation mechanism from dissolution to oxidation in combination with a low concentration of oxygen in the rock layer. These patterns were satisfactorily evaluated by a Hydrus-1D model with reversible and irreversible adsorptions. The information from this work is effective in designing and establishing a reasonable technique for the disposal of hydrothermally altered rocks.
  • Carlito Baltazar Tabelin, Ryosuke Sasaki, Toshifumi Igarashi, Ilhwan Park, Shuichi Tamoto, Takahiko Arima, Mayumi Ito, Naoki Hiroyoshi
    CHEMOSPHERE 188 444 - 454 0045-6535 2017/12 [Refereed][Not invited]
     
    Predicting the fates of arsenic (As) and selenium (Se) in natural geologic media like rocks and soils necessitates the understanding of how their various oxyanionic species behave and migrate under dynamic conditions. In this study, geochemical factors and processes crucial in the leaching and transport of arsenite (As-III), arsenate (As-V), selenite (Se-IV) and selenate (Se-VI) in tunnel-excavated rocks of marine origin were investigated using microscopic/extraction techniques, column experiments, dissolution-precipitation kinetics and one-dimensional reactive transport modeling. The results showed that evaporite salts were important because aside from containing As and Se, they played crucial roles in the evolution of pH and concentrations of coexisting ions, both of which had strong effects on adsorption-desorption reactions of As and Se species with iron oxyhydroxide minerals/phases. The observed leaching trends of As-V, As-III, Se-IV and Se-VI were satisfactorily simulated by one-dimensional reactive transport models, which predict that preferential adsorptions of As-V and Se-IV were magnified by geochemical changes in the columns due to water flow. Moreover, our results showed that migrations of As-III, Se-IV and Se-VI could be predicted adequately by 1D solute transport with simple activity-K '(d) approach, but surface complexation was more reliable to simulate adsorption-desorption behavior of As-V. (C) 2017 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Bijan Samali, Toshifumi Igarashi
    JOURNAL OF CLEANER PRODUCTION 166 1507 - 1520 0959-6526 2017/11 [Refereed][Not invited]
     
    (BFS) and fly ash (FA), on the structural performance, energy requirement and environment impacts of a concrete heavy-duty pavement (HDP) at various curing temperatures. The results of the structural performance indicate that HDP containing up to 70% BFS and HDP containing 30% FA can be comparable in controlling the HDPs designed for highways and airports. Moreover, the results of the environmental impact assessment indicate that the synergy of the by-product and warm water can reduce the energy requirement and CO2 footprint by 5.77%-56.54% and 8.16%-55.5% for the highway and airport HDPs, respectively. Although the elevated curing temperature improves the structural performance and sustainability of the concrete pavements, any delay in concrete production increases energy consumption accordingly. Moreover, a new parameter (del(TE)), which is the time gradient per unit energy consumption developed based on the Laplace transformation, is proposed to characterize the effect of the time delay in concrete production. This parameter indicates that the time required for a unit energy consumption (1 TJ) decreases by 50%, as the curing temperature increases. In conclusion, analysis of the structural design, carbon footprint, and the results of del(TE) indicate that 35 degrees C can be proposed as the optimum water curing temperature for the HDP incorporating by-products. (C) 2017 Elsevier Ltd. All rights
  • Carlito Baltazar Tabelin, Ryosuke Sasaki, Toshifumi Igarashi, Ilhwan Park, Shuichi Tamoto, Takahiko Arima, Mayumi Ito, Naoki Hiroyoshi
    CHEMOSPHERE 186 558 - 569 0045-6535 2017/11 [Refereed][Not invited]
     
    Rocks excavated in tunnel construction projects for roads and railways throughout Japan often leached out hazardous trace elements like arsenic (As) and selenium (Se) upon their exposure to the environment. In nature, the various oxyanionic species of As and Se not only coexist but also exhibit contrasting adsorption-desorption behaviors, so speciation is a crucial factor in their migration through natural geologic media. In this study, the leaching and transport of arsenite (As-III), arsenate (As-V), selenite (Sew) and selenate (Se-VI) in four tunnel-excavated rocks from the Cretaceous-Paleocene Yezo forearc basin were investigated using laboratory column experiments supplemented by batch leaching experiments. The single- and consecutive-batch leaching results revealed that As-III, As-V, Se-IV and Se-VI were released simultaneously, which could be attributed to the rapid dissolution of trace evaporite salts found in the rocks. Arsenic in the leachates was also predominated by As-V while Se-IV and Se-VI concentrations were nearly equal, which are both consistent with predictions of equilibrium Eh-pH diagrams. Under intermittent and unsaturated flow, however, periods when As-III and Se-VI predominated in the effluents were observed. Spatial distributions of As and Se species with depth at the end of the column experiments suggest that migrations of As-III, As-V and Se-IV were delayed, the extent of which depended on the rock. These results indicate that migration and speciation of As and Se in the rocks are controlled by preferential adsorption-desorption reactions, the effects of which were most probably magnified by changes in the pH and concentrations of coexisting ions due to intermittent and unsaturated flow. (C) 2017 Elsevier Ltd. All rights reserved.
  • Banthasith Vongphuthone, Masato Kobayashi, Toshifumi Igarashi
    ENVIRONMENTAL EARTH SCIENCES 76 (19) 1866-6280 2017/10 [Refereed][Not invited]
     
    Arsenic (As) contamination of groundwater is often caused by As leaching from geological formations. This study focused on factors affecting As content in unconsolidated sediments by using three sediment cores in the Ishikari plain, Hokkaido, Japan. The geochemical properties of the sediments were characterized by the chemical and mineral compositions as well as leaching experiments and sequential extractions of As. The results showed that higher As content of 4-9 mg/kg was observed in peat layers with organic matter content > 10 wt%, and that higher As contents deeper than 8 m below the surface were also observed. The deeper sediments were likely to be formed in brackish water conditions due to lower weight ratios of organic carbon content to sulfur content (C/S < 10). The results of the leaching experiments showed that As was mobilized at slightly alkaline region. These indicate that the distribution of As depended on the organic content in the sediments and sedimentation condition, and that the mobility of As in the sediment was affected by pH.
  • P. Tangviroon, R. Hayashi, T. Igarashi
    WATER AIR AND SOIL POLLUTION 228 (5) 0049-6979 2017/05 [Refereed][Not invited]
     
    Hydrothermally altered rocks are frequently encountered when tunnels are constructed in Hokkaido, Japan. High concentraions of hazardous elements, such as arsenic (As), are often released from these rocks into the surrounding environments. Therefore, the rocks are considered potentially hazardous waste. This article describes the effects of water content and oxygen (O-2) concentration in relation to additional layer(s), i.e., surface covering and bottom adsorption layers, on As leaching by using laboratory columns with water content and O-2 concentration sensors. The results show that the use of additional layer(s) has a significant effect on lowering As migration. This was due not only to the adsorption capacity of As by the adsorption layer but also to the water content and O-2 concentration inside the rock layer. The accumulation of pore water was increased in the rock layer in cases with additional layer(s), which resulted in lower O-2 concentration in the rock layer. Consequently, the leaching of As by the oxidation of As-bearing minerals in the rock layer was reduced. Moreover, a longer water-resident time in the rock layer may induce precipitation of Fe oxy-hydroxide/oxide. These results suggest that the geochemical conditions of the rock layer affect As leaching and migration.
  • Carlito Baltazar Tabelin, Suchol Veerawattananun, Mayumi Ito, Naoki Hiroyoshi, Toshifumi Igarashi
    SCIENCE OF THE TOTAL ENVIRONMENT 581 126 - 135 0048-9697 2017/03 [Refereed][Not invited]
     
    The oxidative dissolution of pyrite is an important process in the redox recycling of iron (Fe) and is well-known for its role in the formation of acid mine drainage (AMD), which is considered as the most serious and widespread problem after the closure of mines and mineral processing operations. Because thiS process requires the movement of electrons, common metal oxides in nature that have either semiconducting (e.g., hematite) or insulating (e.g., alumina) properties may have strong effects on it. In this study, changes in the electrochemical behavior of pyrite in the presence of hematite and alumina were investigated. Results showed that the formation of surface bound species directly influenced the anodic and cathodic half-cell reactions as well as the transfer of electrons between these sites. Pyrite pretreated in the air became anodically more reactive than that pretreated in oxygenated water, but the type of oxidizing media had little effect on the cathodic half-cell reaction. The presence of hematite and alumina during pretreatment also had strong effects on the electrochemical properties of pyrite. Chronoamperometry measurements suggest that hematite and alumina enhanced the anodic half-cell reaction but suppressed the cathodic half-cell reaction of pyrite oxidation. Increased anodic half-cell reaction in the presence of hematite could be attributed to electron "bridging" and catalytic effects of this mineral. In contrast, the effects of alumina on the anodic half-cell reaction were indirect and could be explained by the formation of Fe3+-oxyhydroxide surface species during pretreatment. Suppression of the cathodic half-cell reaction by both minerals was attributed to their "protective" effect on cathodic sites. Our results also point to the cathodic half cell reaction as the rate determining-step of the overall oxidative dissolution process.
  • Carlito Baltazar Tabelin, Suchol Veerawattananun, Mayumi Ito, Naoki Hiroyoshi, Toshifumi Igarashi
    SCIENCE OF THE TOTAL ENVIRONMENT 580 687 - 698 0048-9697 2017/02 [Refereed][Not invited]
     
    Pyrite is one of the most common and geochemically important sulfide minerals in nature because of its role in the redox recycling of iron (Fe). It is also the primary cause of acid mine drainage (AMD) that is considered as a serious and widespread problem facing the mining and mineral processing industries. In the environment, pyrite oxidation occurs in the presence of ubiquitous metal oxides, but the roles that they play in this process remain largely unknown. This study evaluates the effects of hematite (alpha-Fe2O3) and alumina (alpha-Al2O3) on pyrite oxidation by batch-reactor type experiments, surface-sensitive characterization of the oxidation layer and thermodynamic/kinetic modeling calculations. In the presence of hematite, dissolved sulfur (S) concentration dramatically decreased independent of the pH, and the formation of intermediate sulfoxy anionic species on the surface of pyrite was retarded. These results indicate that hematite minimized the overall extent of pyrite oxidation, but the kinetic model could not explain how this suppression occurred. In contrast, pyrite oxidation was enhanced in the alumina suspension as suggested by the higher dissolved S concentration and stronger infrared (IR) absorption bands of surface-bound oxidation products. Based On the kinetic model, alumina enhanced the oxidative dissolution of pyrite because of its strong acid buffering capacity, which increased the suspension pH. The higher pH values increased the oxidation of Fe2+ to Fe3+ by dissolved O-2 (DO) that enhanced the overall oxidative dissolution kinetics of pyrite. (C) 2016 Elsevier B.V. All rights reserved.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Toshifumi Igarashi
    RENEWABLE & SUSTAINABLE ENERGY REVIEWS 64 211 - 236 1364-0321 2016/10 [Refereed][Not invited]
     
    This paper discusses the engineering properties of waste glass (WG), including its structural and environmental performance, as an alternative material for the construction of various types of paving systems, including asphalt, concrete, and block pavements. As a first step, an overview of the asphalt, cement, and glass manufacturing industries is provided. Then, a large volume of data is analyzed from various sources in the literature. Particular emphasis is given to laboratory studies of the structural performance and durability of WG. Additionally, the effect of WG on the field performance of the pavements is discussed. The sustainability of the pavements is also evaluated in terms of energy consumption, greenhouse gas emissions, safety, and the heat island phenomenon. In conclusion, the use of WG can improve various phases of pavement life and structure by enhancing the structural performance, durability, environmental friendliness, and aesthetic features of pavements. (C) 2016 Elsevier Ltd. All rights reserved.
  • Shuji Tamamura, Takuma Murakami, Noritaka Aramaki, Akio Ueno, Alam A. K. M. Badrul, Shofa Rijalul Haq, Toshifumi Igarashi, Katsuhiko Kaneko
    INTERNATIONAL JOURNAL OF COAL GEOLOGY 167 230 - 237 0166-5162 2016/10 [Refereed][Not invited]
     
    Since the beginning of the 21st century, various works have sought to enhance coalbed methane (OM) production by stimulating indigenous microbes in coal seams. This concept of microbially enhanced coalbed methane (MECBM) generation relies greatly on the solubilization of the coal, which determines the rate of microbial conversion of the coal into biogenic methane. This study examined the potential of using dilute hydrogen peroxide (H2O2) (0.3%) to solubilize lignite at common subsurface temperatures (10-50 degrees C) via batch experiments at a solid/liquid ratio of 1 g/150 mL. Dissolved organic carbon (maximum 450 mg C/L) and organic acid (formic, acetic, oxalic, malonic, and succinic acid, maximum total of 145 mg C/L) concentrations reached their maximum levels within periods of 1.2 days (at 50 degrees C) to 45 days (at 10 degrees C). H2O2 consumption was a first-order reaction with respect to its concentration, and the linear (r = 0.998) Arrhenius plot for the rate constants yielded its activation energy to be 73 kJ/mol. If the methanogens convert acetic and formic acids to methane, under the current experimental conditions they can produce about 6.0 m3 of methane per ton of lignite. Dilute H2O2 would thus be useful for effective MECBM production at lignite seams. The aromatic-C content of the lignite markedly decreased by about 30% during the reaction, implying high reactivity of catechol structures in the lignite with H2O2. (C) 2016 Elsevier B.V. All rights reserved.
  • Formation of schwertmannite-like and scorodite-like coatings on pyrite and its implications in acid mine drainage control. In: E. Peek, M. Buarzaiga and J. Dutrizac, Eds., Iron Control – Practice and Research, (e-book). Quebec
    C.B. Tabelin, R.D. Corpuz, S. Veerawattananun, M. Ito, N. Hiroyoshi, T. Igarashi
    Canadian Institute of Mining, Metallurgy and Petroleum 133 - 144 2016 [Refereed][Not invited]
  • Shingo TOMIYAMA, Toshihumi IGARASHI, Hiroyuki II, Hideo TAKANO
    Journal of MMIJ 一般社団法人 資源・素材学会 132 (5) 80 - 88 1881-6118 2016 [Not refereed][Not invited]
     
    The understanding of source and flow path of the groundwater provides important strategy for the environmental management of mines. Thus, groundwater samples from the shaft and level in the Shimokawa mine and the surrounding river water samples were taken and the stable isotopes of hydrogen and oxygen and water quality of the samples were analyzed. The results indicate that shallow groundwater starts mainly from mountain-sides and passes through rocks above ore bodies. The simulation of groundwater flow was also conducted. The distribution of velocity vector of the simulated result showed that down streamlines which flows more than 2×10-3 m per day from mountain-sides to the ore bodies were observed. By considering the altitudes of mountain-sides range from 300 to 550 m, these results correspond well with the altitudes estimated from δD and δ18O values of samples.
  • Thuong Huyen Dang, Toshifumi Igarashi, Takuya Shiraiwa
    ENVIRONMENTAL EARTH SCIENCES 75 (1) 1866-6280 2016/01 [Refereed][Not invited]
     
    During the Vietnam War, Bien Hoa airbase was utilized by the US military in the storage and transport of Agents Orange, White, and Blue, which are herbicides/defoliants used during the war. These chemicals used were highly contaminated with dioxins, which were still unknown at that time as carcinogenic chemicals. Thus, accidental spills as well as deliberate disposal of contaminated items within the airbase caused the advertent dioxin problem of the airbase. The relationships of soil properties and dioxin distribution have not yet been considered at this site. Therefore, the objective of this paper was to clarify these relationships using soil samples from boring cores drilled from three areas of the airbase. Dioxins concentrations, total organic carbon (TOC), loss on ignition (LOI), and grain size distribution were analyzed. The results showed that dioxin concentration increased with the increase in TOC. Silty clay with higher TOC of 0.49 % presented the highest toxicity equivalency quantity (TEQ) of 3300 pg-TEQ/g-dw at borehole BH01. Similarly, at BH02, silty clay with the highest TOC of 0.42 % showed the highest TEQ of 760 pg-TEQ/g-dw. The analyzed results of this research also presented a relationship between the TEQ and particle size. It seems to show that the higher concentration of dioxins was found with a ratio of coarse grain size to fine grain size approximately 1:1. However, correlation between dioxins and LOI was not clearly observed. This indicates that mobility of dioxins is sensitive to the TOC of soils.
  • Dang Thuong Huyen, Toshifumi Igarashi, Takuya Shiraiwa
    SPRINGERPLUS 4 2193-1801 2015/06 [Refereed][Not invited]
     
    Bien Hoa airbase is a known dioxin-contaminated hotspot in Vietnam. The contamination occurred during the Vietnam War at the site where dioxins were transported, stored, sprayed, and spilled in the area. Dioxins, which are cancer inducing substances, may transfer from the soil to food crops and finally to human beings living around the area. Many surveys of dioxins in soil, water, organisms, and human have been carried out in this study area since 2002. In this paper vertical distribution of dioxins in undisturbed soil cores were examined. Twelve soil samples from three drilled cores were collected to analyze dioxin levels according to the standard Japanese analytical method. The results showed that the toxicity equivalency quantity (TEQ) in one soil sample at a depth of 2.6 m reached 3,300 pg-TEQ/g-dw. High TEQs were also observed in the clay layer. This anomaly of dioxin concentrations could be attributed to the affinity of dioxins for the clay layer. The isomer patterns in the soils were different from those in the soil of Hokkaido in that 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) was the most dominant in the soil sample. This indicates that the dioxins originate from a defoliant Agent Orange disposed at the site after the Vietnam War.
  • Shuichi Tamoto, Carlito Baltazar Tabelin, Toshifumi Igarashi, Mayumi Ito, Naoki Hiroyoshi
    JOURNAL OF CONTAMINANT HYDROLOGY 175 60 - 71 0169-7722 2015/04 [Not refereed][Not invited]
     
    Sedimentary rocks of marine origin excavated from tunnel construction projects usually contain background levels of hazardous trace elements, but when exposed to the environment, they generate leachates with concentrations of arsenic (As), selenium (Se) and boron (B) exceeding the WHO guideline for drinking water. In this study, the leaching of As, Se and B was evaluated under in situ conditions at various flow patterns, particle size distributions and column thicknesses. The results showed that these trace elements were leached out of the rock via short and long term mechanisms. In the short term, all three elements were rapidly and simultaneously released due to the dissolution of soluble evaporite salts formed from entrapped sea water of the Cretaceous. After their rapid release, however, these trace elements behaved differently as a result of their contrasting adsorption affinities onto minerals like clays and Feoxyhydroxides, which were further influenced by the pH, presence of coexisting ions and speciation of the trace elements. Selenium was quickly and easily transported out of the columns because it was mostly present as the very mobile selenate ion (Se[VI]). In comparison, the migration of As and B was hindered by adsorption reactions onto mineral phases of the rock Boron was initially the least mobile among the three because of its preferential adsorption onto clay minerals that was further enhanced by the slightly alkaline pH and high concentrations of Ca2+ and Na+. However, it was gradually re-mobilized in the latter part of the experiments because it was only weakly adsorbed via outer sphere complexation reactions. In the long term, the rock continued to release substantial amounts of As, Se and B via pyrite oxidation and adsorption/desorption reactions, which were regulated by the temperature and rainfall intensity/frequency on site. (C) 2015 Elsevier B.V. All rights reserved.
  • Shuji Tamamura, Akio Ueno, Noritaka Aramaki, Hiroyuki Matsumoto, Kagemi Uchida, Toshifumi Igarashi, Katsuhiko Kaneko
    ORGANIC GEOCHEMISTRY 81 8 - 19 0146-6380 2015/04 [Not refereed][Not invited]
     
    The effect of oxidative weathering on the composition of sedimentary organic matter (SOM) of lignite, subbituminous coal, quartzose arenite, siliceous mudstone, siliceous shale and diatomaceous shale was investigated in Hokkaido, Japan, in a subarctic humid climate. For 15 samples in total, a humic substance extraction method was applied to divide SOM into lipid-C, humin-C and alkali soluble-C. The alkali soluble-C was further divided into fulvic acid (FA)-C, humic acid (HA)-C and a smaller molecular size fraction (SMSF)-C, which comprised organic molecules able to pass through a dialysis membrane (< 1000 Da) during the HA and FA purification processes. The alkali soluble-C (8-750 g/kg) increased with the degree of sample weathering in compensation for lowering of humin-C. For the alkali soluble-C, HA-C (undetectable to 698 g/kg) became dominant with sample weathering, in contrast to FA-C and SMSF-C. These observations imply that oxidative weathering converts humin-C into alkali soluble-C (mainly HA-C). The C-13 nuclear magnetic resonance (NMR) analysis (precision +/- 2.4%) revealed higher aromatic-C content of HA (average 40%) as compared to bulk humin (average 33%), suggesting that the re-generated HA was derived from condensed products (aromatic-C rich) in the humin, rather than from recalcitrant biomolecules (alkyl-C rich) in that fraction. The longer emission wavelength of the HA and FA from weathered samples in the excitation-emission matrix (EEM) spectra (precision +/- 1.0%) is ascribed to the abundance of oxidized aromatic moieties, with the higher O/C atomic ratio of HA and FA from the weathered samples. (C) 2015 Elsevier Ltd. All rights reserved.
  • Nohara Yokobori, Toshifumi Igarashi, Tetsuro Yoneda
    ENGINEERING GEOLOGY FOR SOCIETY AND TERRITORY, VOL 6: APPLIED GEOLOGY FOR MAJOR ENGINEERING PROJECTS 429 - 433 2015 [Refereed][Not invited]
     
    Soil and groundwater pollution caused by acid rock drainage (ARD) containing heavy metals leached from mineralized rocks is a serious environmental problem. Mineralized rocks are widespread throughout Hokkaido, Japan, and several tunnels for the Hokkaido Bullet Train Line are planned to be constructed through these mineralized areas. In this study, batch and column leaching experiments were conducted to investigate the leaching characteristics of heavy metals from the mineralized rock samples collected in these areas. The results showed that the mineralized samples contained substantial amounts of sulfide minerals (e.g., sphalerite (ZnS)), and that cadmium (Cd) was incorporated in some of these sulfide minerals. Moreover, the leaching concentrations of lead (Pb), Cd and arsenic (As) were higher than the Japanese environmental standards. The results of the column leaching experiment showed that these mineralized rocks could continuously release high concentrations of heavy metals for a long time. Therefore, such rocks should be disposed of properly to prevent the contamination of the surrounding environment.
  • Yasunori Mahara, Tomoko Ohta, Noritoshi Morikawa, Takanori Nakano, Minoru Tokumasu, Satoshi Hukutani, Tomochika Tokunaga, Toshifumi Igarashi
    APPLIED GEOCHEMISTRY 50 142 - 149 0883-2927 2014/11 [Not refereed][Not invited]
     
    Dating using a combination of H-3 and He-3 is believed to be the most practical method for estimating the short residence time of shallow groundwater. However, this method must estimate tritiogenic He-3 alone and tends to overestimate the residence time of groundwater, if terrigenic He-3 from the mantle cannot be excluded from the total dissolved He-3. We demonstrate the exclusion of terrigenic He-3 in the Saijo Basin, where mantle He is easily released along the major active fault, Median Tectonic Line. The He-3/He-4 ratios suggest that the west bank of the Kamo River, which lies within the basin, has experienced greater emanations of mantle He than the east bank. We estimate the residence times to be 1.1-96 years by the proposed exclusion method. (C) 2014 Elsevier Ltd. All rights reserved.
  • TAMAMURA SHUJI, AKATSUKA MAIKO, IKAWA REO, KOSHIGAYA MASARU, SHIMIZU SATORU, UENO AKIO, OMI YASUSHI, KANEKO KATSUHIKO, IGARASHI TOSHIFUMI, MARUI ATSUNAO
    地球化学 48 (1) 39 - 50 0386-4073 2014/03/25 [Not refereed][Not invited]
  • Carlito Baltazar Tabelin, Ayaka Hashimoto, Toshifumi Igarashi, Tetsuro Yoneda
    SCIENCE OF THE TOTAL ENVIRONMENT 473 244 - 253 0048-9697 2014/03 [Refereed][Not invited]
     
    Sedimentary rocks excavated in Japan from road- and railway-tunnel projects contain relatively low concentrations of hazardous trace elements like boron (B), arsenic (As) and selenium (Se). However, these seemingly harmless waste rocks often produced leachates with concentrations of hazardous trace elements that exceeded the environmental standards. In this study, the leaching behaviors and release mechanisms of B, As and Se were evaluated using batch leaching experiments, sequential extraction and geochemical modeling calculations. The results showed that B was mostly partitioned with the residual/crystalline phase that is relatively stable under normal environmental conditions. In contrast, the majority of As and Se were associated with the exchangeable and organics/sulfides phases that are unstable under oxidizing conditions. Dissolution of water-soluble phases controlled the leaching of B, As and Se from these rocks in the short term, but pyrite oxidation, calcite dissolution and adsorption/desorption reactions became more important in the long term. The mobilities of these trace elements were also strongly influenced by the pH of the rock-water system. Although the leaching of Se only increased in the acidic region, those of B and As were enhanced under both acidic and alkaline conditions. Under strongly acidic conditions, the primarily release mechanism of B, As and Se was the dissolution of mineral phases that incorporated and/or adsorbed these elements. Lower concentrations of these trace elements in the circumneutral pH range could be attributed to their strong adsorption onto minerals like Al-/Fe-oxyhydroxides and clays, which are inherently present and/or precipitated in the rock-water system. The leaching of As and B increased under strongly alkaline conditions because of enhanced desorption and pyrite oxidation while that of Se remained minimal due to its adsorption onto Fe-oxyhydroxides and co-precipitation with calcite. (c) 2013 Elsevier B.V. All rights reserved.
  • Carlito Baltazar Tabelin, Ayaka Hashimoto, Toshifumi Igarashi, Tetsuro Yoneda
    SCIENCE OF THE TOTAL ENVIRONMENT 472 620 - 629 0048-9697 2014/02 [Not refereed][Not invited]
     
    Sedimentary rocks of marine origin excavated in tunnel projects were recently identified as potentially hazardous because they could release significant amounts of toxic trace elements when exposed to the environment. This study investigated the leaching characteristics of B, As, Se and the major coexisting ions under various conditions to identify the factors and processes controlling their evolution in the leachate. In addition, we evaluated whether the parameters of the currently used leachability test for excavated rocks were adequate. Although the leachabilities of B, As and Se similarly increased at longer contact times, only those of B and As were influenced by the mixing speed and/or liquid-to-solid ratio (L/S). The majority of trace elements dissolved in the leachate originated from the dissolution of soluble salts formed from seawater of the Cretaceous trapped during the formation of the sedimentary rocks. Moreover, the alkaline pH of the leachates could be attributed to the simultaneous dissolutions at varying degrees of the mineral components of the rocks as well as the precipitation of clay minerals. In the leaching test of excavated rocks for regulatory purposes, the best values of contact time and mixing speed should represent conditions of the highest trace element extractabilities, which in this study were found at longer contact times (> 48 h) and the fastest mixing speed (200 rpm). The most appropriate L/S for the leaching test is 10 because it was around this L/S that the extractabilities and leaching concentrations of the trace elements were simultaneously observed at their highest values. (C) 2013 Elsevier B.V. All rights reserved.
  • IGARASHI TOSHIFUMI, UEDA TAKAHIRO, HOKORA HIDEYUKI, JO MAYUMI, KATO KIN'YA, MISHIRO MASATAKA, KUDO HAJIME
    J MMIJ 130 (2/3) 60 - 64 1881-6118 2014/02/01 [Not refereed][Not invited]
  • Carlito Baltazar Tabelin, Toshifumi Igarashi, Takahiko Arima, Daiki Sato, Takeshi Tatsuhara, Shuichi Tamoto
    GEODERMA 213 163 - 172 0016-7061 2014/01 [Not refereed][Not invited]
     
    Construction of tunnels in Hokkaido, Japan often excavates rocks containing substantial amounts of arsenic (As) and boron (B). When these rocks are exposed to the environment, As and B are leached out that could potentially contaminate the surrounding soil and groundwater. Natural geologic materials contain minerals like Al-/Feoxyhydroxides/oxides that have As and B adsorption capabilities. Because these materials are widespread and readily available, they could be utilized in the mitigation of As and B leached out from these sources. This paper describes the ability of three natural geologic materials (i.e., pumiceous tuffs, partly-weathered volcanic ashes and coastal marine sediments) to sequester As and B from aqueous solutions and the actual leachate of a hydrothermally altered rock. The adsorption of As fitted well with either the Langmuir or Freundlich isotherm while that of B followed the Henry-type model (linear). Among the samples, those containing substantial amorphous Al and Fe exhibited higher As adsorption. However, the distribution coefficient of B only had a moderate positive correlation with these amorphous phases. The best adsorbent among these natural geologic materials was utilized in the adsorption layer of the column experiments. Adsorption of As was more effective the thicker the adsorption layer, but this retardation was only temporary due to significant changes in the pH. In contrast, the adsorption layer only retarded the migration of B to a limited extent. (C) 2013 Elsevier B.V. All rights reserved.
  • NARUSE TATSURO, KAWASHIMA TAKESHI, IGARASHI TOSHIFUMI
    土木学会論文集 G(環境)(Web) 70 (4) 78-85 (J-STAGE)  2185-6648 2014 [Not refereed][Not invited]
  • Tomoko Ohta, Yasunori Mahara, Takumi Kubota, Toshifumi Igarashi
    ANALYTICAL SCIENCES 29 (10) 941 - 947 0910-6340 2013/10 [Refereed][Not invited]
     
    We measured Cs-134 and Cs-137 in the surface soil of the Kanto loam in the eastern Tokyo metropolitan area and the Nishiyama loam in Nagasaki, Japan. The observed Cs-137 deposition in the Kanto loam from the Fukushima nuclear power plant (NPP) accident ranged from 4.0 to 77 kBq m(-2), which corresponds to 0.3 - 5 times of that in the Nishiyama loam. The Cs-137 retardation factor in the Kanto loam obtained seven months after the Fukusima NPP accident and in the Nishiyama loam after 36 and 38 years from the detonation of the Pu atomic bomb (A-bomb) ranged from 180 to 260 and 2000 to 10000, respectively. This difference in the retardation factors is attributed to an aging effect that corresponds to seven months and 36 to 38 years after the deposition of Cs-137 occurred on the soil minerals.
  • ENDO RYO, TAMAMURA SHUJI, OMI YASUSHI, KANEKO KATSUHIKO, KANEKO KATSUHIKO, IGARASHI TOSHIFUMI
    地球化学 47 (1) 21 - 40 0386-4073 2013/04/10 [Not refereed][Not invited]
  • Carlito Baltazar Tabelin, Toshifumi Igarashi, Tetsuro Yoneda, Shuji Tamamura
    Engineering Geology 156 58 - 67 0013-7952 2013/04/01 [Refereed][Not invited]
     
    We have developed the adsorption-layer system for the simple and effective disposal of excavated rocks containing hazardous pollutants like arsenic (As). In this study, adsorption properties of natural and artificial materials including their performance in an actual altered rock-adsorption layer setup were evaluated. The adsorption of As[V] and As[III] onto all adsorbents fitted well with the Langmuir isotherm, indicating monolayer adsorption and progressive saturation of adsorption sites. All adsorbents were capable of As[V] and As[III] sequestration, but As[V] was more strongly adsorbed than As[III] based on the Langmuir isotherm. Also, artificial adsorbents were more efficient per unit weight than the natural adsorbent. Using the Langmuir isotherms and sequential extraction results, appropriate adsorbent dosages were estimated and then applied to an actual altered rock-adsorption layer column setup. The leaching concentration of As was lowered below 10 μg/L throughout the experiment regardless of the kind of adsorbent used. This suggests that the adsorption-layer system is a promising alternative to special landfills in the disposal of excavated rocks enriched with As. © 2013 Elsevier B.V.
  • Omar Roberto Salinas Villafane, Toshifumi Igarashi, Mitsuru Kurosawa, Toshio Takase
    WATER AIR AND SOIL POLLUTION 224 (3) 1 - 12 0049-6979 2013/03 [Refereed][Not invited]
     
    This paper addresses the geochemical evolution, volumetric water content, and temperature of porewater when constructing different soil layers to improve the surface acidic conditions on a slope at a closed mine. Three cases were set under different layer systems. Case 1 was solely composed of surface-weathered rocks. A vegetation layer was constructed on the surface rocks in case 2, whereas a top vegetation and bottom low-permeable layers were constructed on the rocks in case 3. In both cases, a soil-cement layer was constructed to prevent landslides. Porewater sampling systems and soil sensors were set at different depths to collect porewater and measure the volumetric water content and temperature. The results showed that, when no layers were applied (case 1), high concentrations of heavy metals and low pH values were observed regardless of the depth and season. When a vegetation layer (case 2) was applied, a dramatic decrease in heavy metal concentrations was observed, similar to the results in case 3. In both cases, pH values were circumneutral. Moreover, the addition of the low-permeable layer reduced the infiltration of rainfall through the layers by considering the changes in volumetric water content. Also, the results of case 1 were compared with those obtained at a flat surface under similar conditions. On the slope, the pH was more acidic, and heavy metal concentrations were higher. These suggest that the dissolution of heavy metals from the weathered rocks into the porewater is enhanced on the sloping surface due to a longer solid-liquid interaction time.
  • Toshifumi Igarashi, Ryosuke Sasaki, Carlito B. Tabelin
    INTERNATIONAL CONFERENCE ON EARTH SCIENCE AND TECHNOLOGY PROCEEDINGS 6 105 - 113 1878-5220 2013 [Refereed][Not invited]
     
    Batch leaching experiments were conducted to elucidate the leaching behaviors and chemical forms of arsenic (As) and selenium (Se) from excavated mudstones. The results showed that As and Se concentrations in the leachate were higher than the environmental standards (10 mu g/L), and that the major chemical forms of As and Se were arsenate (As(V)) and selenate (Se(VI)), respectively. Consecutivebatch leaching experiments showed that the major chemical form of As was As(V) regardless of the number of extraction whereas that of Se changed from Se(VI) to selenite (Se(IV)) with the number of extraction. These results agreed with the calculated results by geochemical modeling. Understanding the major chemical species of hazardous elements leached from mudstones is valuable in the mitigation of these potential sources of contamination.
  • Yasunori Mahara, Tomoko Ohta, Tomochika Tokunaga, Hiroyuki Matsuzaki, Eiji Nakata, Yuki Miyamoto, Yukihiro Mizuochi, Toshiharu Tashiro, Masahiro Ono, Toshifumi Igarashi, Keisuke Nagao
    APPLIED GEOCHEMISTRY 27 (12) 2389 - 2402 0883-2927 2012/12 [Refereed][Not invited]
     
    Fifty-three samples, including brines associated with oil and natural gas reservoirs and groundwater samples from deep boreholes, were collected from the Pacific and Japan Sea coastal regions in Japan. The I-129/I-127 and Cl-36/Cl ratios, and stable isotopes (delta D and delta O-18) are compared to investigate differences related to the geotectonic settings of the two regions. The dD and delta O-18 data indicate that brine and groundwater from the Pacific coastal region reflect mixing of meteoric water with connate seawater in the pores of sedimentary rocks. On the other hand, brine and groundwater from the Japan Sea coastal region have been hydrothermally altered. In particular, brines associated with petroleum accumulations at Niigata and Akita showed the same isotopic characteristics as fluids found in the Kuroko deposits of the Green Tuff region in northeastern Japan. There is little difference in the Cl-36/Cl ratios in brine and groundwater from the Pacific and Japan Sea coasts. Most brine and some deep groundwater, except those from the Pleistocene Kazusa Group, have already reached the average secular equilibrium ratio of 9.9 +/- 2.7 x 10 x (15) for their mudstone and sandstone reservoirs. There was no correlation between the Cl-36/Cl ratios and differences in geotectonic setting between the Pacific and the Japan Sea coast. The molar I/Br ratio suggests that the I in all of water samples was of biogenic origin. The average I-129/I-127 ratio was 290 +/- 130 x 10 (15) to 294 +/- 105 x 10 (15) in both regions, showing no relationship to the different geotectonic settings. The uncontaminated brine and groundwater samples are likely to have retained the original I-129/I-127 ratios of marine I released from the old organic matter stored in sedimentary rock. (C) 2012 Elsevier Ltd. All rights reserved.
  • Omar R. Salinas Villafane, Toshifumi Igarashi, Mitsuru Kurosawa, Toshio Takase
    APPLIED GEOCHEMISTRY 27 (12) 2271 - 2279 0883-2927 2012/12 [Refereed][Not invited]
     
    Potentially toxic metals, such as Cu, Pb and Zn, are leached from weathered rocks at many closed mine sites due to the acidic environments and mineralogical modifications. The mobilized toxic metals may cause contamination of surrounding water bodies. In this study, both laboratory column experiments and field observations at a former mine located in the north of Japan were carried out to compare the leaching behavior of Cu, Pb and Zn. The thickness of the surface weathered rock was varied (10, 20 and 30 cm) for the columns experiments while porous cups for porewater sampling were set up at different depths (GL-15, -45, -70, and -95 cm) for the field observations. Deionized water was added once a week over 75 weeks to the columns to simulate rainfall while porewater was extracted by a vacuum pump in several sampling campaigns (over 18 months). Similar low pH and leaching behavior of potentially toxic metals were observed for column experiments and field observations. A moderate increase in concentration with depth was observed for Cu and Zn. However, no increase in concentration was observed for Pb. This suggests that the leaching of Cu and Zn is enhanced by the length of the flow pathway through the weathered rock layer while Pb concentration is restricted by the precipitation of insoluble Pb sulfate. Thus, the thickness of the weathered rock layer is an important parameter that should be taken into consideration to estimate the loads of some potentially toxic metals, which is important when designing remediation schemes. (C) 2012 Elsevier Ltd. All rights reserved.
  • Carlito Baltazar Tabelin, Toshifumi Igarashi, Tetsuro Yoneda
    APPLIED GEOCHEMISTRY 27 (12) 2300 - 2314 0883-2927 2012/12 [Refereed][Not invited]
     
    The effects of water residence time and anoxic conditions on the mobilization and speciation of As in a calcite-and pyrite-bearing altered rock excavated during a road-tunnel project has been evaluated using batch and column laboratory experiments. Higher infiltration rates (i.e., shorter water residence times) enhanced the leaching of As due to the higher pH values of the effluents and more rapid transport of dissolved As through the columns. The concentration of As in the effluent also increased under anoxic conditions regardless of the water residence time. This enhanced leaching of As under anoxic conditions could be attributed to a significant pH increase and decreased Fe oxyhydroxide/oxide precipitation compared to similar experiments done under ambient conditions. Processes that controlled the evolution of pH and the temporal release mechanisms of As under anoxic conditions were identical to those previously observed under ambient conditions: the dissolution of soluble phases, pyrite oxidation, co-precipitation and/or adsorption/desorption reactions. Speciation of As in the column experiments could partly be attributed to the pH-dependent adsorption of As species onto Fe oxyhydroxide/oxide precipitates. Moreover, apparent equilibrium of the total As and As[III] concentrations was delayed under anoxic conditions in both batch and column experiments. (C) 2012 Elsevier Ltd. All rights reserved.
  • Omar R. Salinas Villafane, Toshifumi Igarashi, Shusaku Harada, Mitsuru Kurosawa, Toshio Takase
    ENVIRONMENTAL MONITORING AND ASSESSMENT 184 (12) 7665 - 7675 0167-6369 2012/12 [Refereed][Not invited]
     
    This paper describes the chemistry of porewater when constructing different soil layers on acidic weathered rock of a closed mine to remediate the surface environment. Three cases were set on a flat surface of the site, all under different layer systems. Case 1 was only composed of weathered rocks. A top neutralization layer was constructed on the weathered rocks in case 2, whereas both an upper low-permeable and middle neutralization layers were constructed on the weathered rocks in case 3. The low-permeable layer of 30 cm thick consists of clay, and the neutralization layer of 30 cm thick consists of the mixture of the weathered rock and calcium carbonate as a neutralizer. Porewater sampling systems and soil sensors to measure temperature, water content, and electrical conductivity were set at different depths. In case 1, steadily high concentrations of heavy metals were observed regardless of the depth, and the pH ranged from 2 to 4. In cases 2 and 3, a dramatic decrease in concentrations of heavy metals was observed, even below the neutralization layer. For both cases, pH values were circumneutral. There were no significant seasonable changes in heavy metals concentrations and pH of porewater by considering the temperature and precipitation. In addition, the water content of the layers in case 3 fluctuated more mildly than that in cases 1 and 2, indicating that the low-permeable layer reduced the rate of infiltration. Therefore, a significant reduction in the load of heavy metals released from the site can be achieved by both implementing neutralization and low-permeable layers.
  • SAKAI Toshiaki, IOKA Seiichiro, IGARASHI Toshifumi
    Jour. Japan Soc. Eng. Geol. 日本応用地質学会 53 (4) 172 - 182 0286-7737 2012/10 [Refereed][Not invited]
  • Carlito Baltazar Tabelin, Amir Hamzah Mohd Basri, Toshifumi Igarashi, Tetsuro Yoneda
    WATER AIR AND SOIL POLLUTION 223 (7) 4153 - 4167 0049-6979 2012/09 [Refereed][Not invited]
     
    This paper describes the leaching behavior and release mechanisms of arsenic (As), boron (B), and selenium (Se) from excavated rocks using sequential extraction for solid-phase fractionation, batch experiments with pH variation, and consecutive batch experiments with changes in the solid-liquid mixing ratios. Arsenic in the excavated rock was mostly found with the sulfides/organic matter fraction while majority of the leachable B and Se were associated with the exchangeable phases. The leaching of As was strongly pH dependent, Se was pH dependent only around the acidic region, and B was pH independent. Consecutive washing technique with deionized water effectively lowered the B and Se concentrations in the leachate below the drinking water standards of Japan, but was inefficient in the removal of As. Arsenic exhibited non-conservative leaching behavior and its movement was affected by processes like dissolution, precipitation, and pyrite oxidation. In contrast, B and Se behaved more conservatively, resulting in their easy removal from the excavated rock by simple washing and dilution.
  • TAMAMURA SHUJI, ENDO RYO, SHIMIZU SATORU, IWATSUKI TERUKI, AMANO YUKI, OMI YASUSHI, IGARASHI TOSHIFUMI
    J MMIJ 128 (10/11) 570 - 575 1881-6118 2012/09 [Refereed][Not invited]
  • Tomoko Ohta, Yasunori Mahara, Takumi Kubota, Satoshi Fukutani, Keiko Fujiwara, Koichi Takamiya, Hisao Yoshinaga, Hiroyuki Mizuochi, Toshifumi Igarashi
    JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 111 38 - 41 0265-931X 2012/09 [Refereed][Not invited]
     
    We measured the concentrations of I-131, Cs-134, and Cs-137 released from the Fukushima nuclear accident in soil and rainwater samples collected March 30-31, 2011, in lbaraki Prefecture, Kanto district, bordering Fukushima Prefecture to the south. Column experiments revealed that all I-131 in rainwater samples was adsorbed onto an anion-exchange resin. However, 30% of I-131 was not retained by the resin after it passed through a soil layer, suggesting that a portion of (131)1 became bound to organic matter from the soil. The Cs-137 migration rate was estimated to be approximately 0.6 mm/y in the Kanto area, which indicates that contamination of groundwater by Cs-137 is not likely to occur in rainwater infiltrating into the surface soil after the Fukushima accident. (C) 2011 Elsevier Ltd. All rights reserved.
  • Carlito Baltazar Tabelin, Toshifumi Igarashi, Shuichi Tamoto, Ryohei Takahashi
    JOURNAL OF GEOCHEMICAL EXPLORATION 119 (0) 17 - 31 0375-6742 2012/08 [Not refereed][Not invited]
     
    This paper describes the enrichment of hydrothermally altered volcanic and sedimentary rocks with arsenic (As) and lead (Pb), and the effects of pyrite and calcite on the mobilities and release mechanisms of these toxic elements under oxic and anoxic conditions. Enrichment of the altered rock with As and Pb predominantly occurred in precipitated pyrite grains and not on the alumino-silicate minerals making up the matrix of the rock. Arsenic was incorporated in pyrite grains formed during alteration in both volcanic and sedimentary rocks, but Pb was only found in the pyrite grains of the volcanic rock samples. When in contact with water, altered volcanic rocks had acidic pH while altered sedimentary rocks had alkaline pH. The mobilities of both As and Pb from the altered rocks were enhanced at acidic and alkaline pH and a minimum was observed in the circumneutral pH under both oxic and anoxic conditions. The absence of O-2 retarded the oxidation of pyrite most notably in the alkaline region but not in the acidic and circumneutral pH. The absence of CO2 increased the pH of samples with significant calcite content but did not affect those containing substantial amounts of pyrite. Increasing the CO2 also had insignificant effect on the concentrations of As and Pb in the leachate. The mechanisms controlling the mobilization of As and Pb from these rocks like dissolution of soluble secondary minerals, pyrite oxidation and adsorption were all related to pyrite while the pH of the rock when in contact with water was controlled by pyrite and calcite. Thus, excavated waste rocks that have been altered can be grouped based on the relative abundance of pyrite and calcite and their pH when in contact with water. (C) 2012 Elsevier B.V. All rights reserved.
  • Takeshi Tatsuhara, Takahiko Arima, Toshifumi Igarashi, Carlito Baltazar Tabelin
    ENGINEERING GEOLOGY 139 76 - 84 0013-7952 2012/06 [Refereed][Not invited]
     
    Hydrothermally altered rock excavated in a tunnel project produces acidic leachate containing hazardous elements that include arsenic (As), lead (Pb), copper (Cu) and zinc (Zn). To mitigate this problem, this paper evaluated a combined neutralization-adsorption system that used readily available and cheap reagents like calcium carbonate (CaCO3) and partly-weathered volcanic ash. Batch neutralization experiments showed that CaCO3 was effective in raising the pH of the leachate around neutral while the batch adsorption experiments illustrated that the volcanic ash sample collected near the tunnel project area was highly capable of adsorbing arsenate (As[V]), Pb, Cu and Zn. Under column conditions, the amount of hazardous elements released from the rock increased by several folds and their breakthrough curves had flushing-out trends. The mechanisms of As and heavy metals release probably include the dissolution of soluble phases and pyrite oxidation. Addition of CaCO3 in the column experiments based on estimates from the batch results underestimated the amount of neutralizer needed to adjust the effluent pH to around 8, resulting only in slight increase of the pH. Nevertheless, the presence of CaCO3 drastically reduced the amount of hazardous elements released from the altered rock especially during the initial stages of the column experiments. Combining neutralization and adsorption effectively reduced the amount of As and heavy metals in the effluent throughout the duration of the column experiments, which is attributed to the slight neutralizing effect of volcanic ash that raised the pH around circumneutral as well as its rich Al and Fe oxyhydroxide/oxide contents. The combined system immobilized the hazardous elements through a combination of co-precipitation and adsorption reactions and showed potential as an alternative method for the disposal of altered rocks producing acidic leachate. (C) 2012 Elsevier B.V. All rights reserved.
  • Construction of natural neutralization facilities for alkaline tunnel seepage using atmospheric carbon dioxide
    Furutya, Y, Igarashi, T, Matsumoto, T, Okawa, R
    Journal of JSCE 68 (2) 29 - 39 2012 [Refereed][Not invited]
  • Carlito Baltazar Tabelin, Toshifumi Igarashi, Ryohei Takahashi
    APPLIED GEOCHEMISTRY 27 (1) 326 - 342 0883-2927 2012/01 [Refereed][Not invited]
     
    This paper describes the mobilization and speciation of As found in hydrothermally altered rock under oxic column conditions. The altered rock sample was obtained from a tunnel project located in the Nakakoshi area of Hokkaido, Japan, whose geology is represented by slate, shale and sandstone. This area has undergone silicification, pyritization and argillic alteration resulting in As-enrichment of the rock. Results of the column experiments show that the infiltration rate, bulk density and rock bed thickness affected the duration of water residence, which in turn influenced the pH of the rock-water system. Coexisting ions most notably Ca2+ at amounts greater than ca. 50 mg/L retarded the mobilization of As. Mobilization of As from the rock with time occurred in two stages: stage 1 (weeks 1-20) with higher As leaching and stage 2 (weeks 20-76) characterized by nearly constant As release. In addition, pore water As concentrations revealed that the columns developed into two regions: the top half where most of the leaching occurred and the bottom part dominated by adsorption. Thus, the mechanism controlling the mobilization of As from the rock is a combination of one or more of the following processes: dissolution of soluble As-bearing fractions, pyrite oxidation and adsorption reactions. Arsenite (As[III]) was the dominant species in the effluent at the start of the experiment in columns with shorter water residence time and lower pH conditions (<8). On the other hand, arsenate (As[V]) was the major inorganic species released from the rock at higher pH (8-9.5) and when the system was close to equilibrium. Speciation of As with depth also indicated that As[III] disappeared around the bottom half of the columns, probably as a result of adsorption and/or oxidation. Arsenic speciation is partially controlled by the pH dependent adsorption of As species. The important adsorbent phases in the rock included Fe-Al oxides/oxyhydroxides, clay minerals and organic matter, which permitted the columns to attenuate additional As loadings including As[III]. Implications of these results on the design of a novel disposal method for these altered rocks include the enhancement of As adsorption through the addition of natural or artificial adsorbents and the utilization of a covering soil with low permeability to minimize rainwater infiltration into the rock. (C) 2011 Elsevier Ltd. All rights reserved.
  • Immobilization of arsenic released from excavated rock affected by hydrothermal alteration
    C.B. Tabelin, T. Igarashi, T. Yoneda
    Proc. of the 4th Regional Conference on Geological Engineering 192 - 202 2012 [Refereed][Not invited]
  • Leaching of Arsenic, Boron, Selenium and Heavy Metals from Tunnel Excavated Rocks and Their Mitigation
    C.B. Tabelin, T. Arima, T. Igarashi, T. Yoneda
    Proc. of the 2nd Int. Conference on Advances in Mining and Tunneling 382 - 390 2012 [Refereed][Not invited]
  • SAKAI Toshiaki, IOKA Seiichiro, IGARASHI Toshifumi
    Journal of the Japan Society of Engineering Geology 一般社団法人 日本応用地質学会 53 (4) 172 - 182 0286-7737 2012 [Not refereed][Not invited]
     
    The cross-sectional modeling of groundwater flow was carried out with the help of geological surveying, piezometer monitoring, and the chemical composition estimation of groundwater to investigate the groundwater flow system in the alluvial plain in Sarobetsu moor located in the northern part of Hokkaido. According to the previous studies, the geology of the alluvium is mud-rich. The Ho-la stratum (clay layer), which was deposited during the Hypsithermal age, had low permeability. The observation of the hydraulic head and chemical composition of the groundwater indicated that the Ho-la stratum inhibited vertical groundwater flow. In addition, the highest hydraulic head was measured at the basement rock in the eastern part of the moor and hydraulic heads were found to decrease in shallow areas and in the western part of the moor. The highest hydraulic head was guessed to have formed on account of tectonic movements. The distribution of the highest hydraulic head was estimated by analysis use with the groundwater flow model.
  • 玉村修司, 遠藤亮, 大味泰, 岩月輝希, 天野由記, 五十嵐敏文
    資源・素材 2011 2 - 3 0919-7915 2011/09/26 [Not refereed][Not invited]
  • Seiichiro Ioka, Toshiaki Sakai, Toshifumi Igarashi, Yoji Ishijima
    ENVIRONMENTAL EARTH SCIENCES 64 (1) 143 - 149 1866-6280 2011/09 [Refereed][Not invited]
     
    The in situ redox potential (Eh) in anoxic groundwater with high methane and iron contents (approximately 12.3 and 28.4 mg/L, respectively) was potentiometrically measured to identify the processes that control Eh. The measured Eh ranged from -213 to -187 mV; it had an inverse correlation with the concentration of methane and no correlation with that of iron. The saturation indices indicate that goethite and amorphous FeS were nearly at solubility equilibrium. A comparison of the measured Eh with those calculated for the particular redox pairs indicates that either Fe(2+)/FeOOH or CH(4)/CO(2), but not sulfur redox pairs, controlled the measured Eh. The inverse relationship between measured Eh and methane concentration suggests possible control of the redox conditions by the CH(4)/CO(2) redox pair. Furthermore, the equilibrium solubility state of goethite, which has higher crystallinity and lower solubility than Fe(OH)(3) indicates that the iron reaction was electrochemically irreversible. This further supports the contribution of the CH(4)/CO(2) pair to controlling the measured Eh of groundwater.
  • Arima, T, Sato, D, Igarashi, T, Tamoto, S, Tatsuhara, T
    Jour. Japan Soc. Eng. Geol. 52 (3) 88 - 96 0286-7737 2011/08 [Refereed][Not invited]
  • Seiichiro Ioka, Toshiaki Sakai, Toshifumi Igarashi, Yoji Ishijima
    ENVIRONMENTAL MONITORING AND ASSESSMENT 178 (1-4) 171 - 178 0167-6369 2011/07 [Refereed][Not invited]
     
    This study was undertaken to investigate the redox potential (Eh) of sulfidic groundwater in unconsolidated sediments. The Eh was determined by long-term (several days to several weeks) continuous in situ potentiometric measurements using a platinum (Pt) electrode. The Eh values measured in two monitoring campaigns were -259 and -202 mV, respectively. Chemical analysis of groundwater showed that the redox species in the groundwater were sulfide (S(2 -aEuro parts per thousand)) and iron, respectively. The saturation indices calculated from the chemical analysis results indicated that FeS((am)) and mainly mackinawite were close to equilibrium in the analyzed waters. Comparison of the measured Eh values with those calculated using different redox couples revealed that the Eh values measured in the first monitoring campaign were nearly equal to those calculated using HS(-)/SO(4)(2-), S(2-)/SO(4)(2-), FeS((am))/SO(4)(2-), and mackinawite/SO(4)(2-) on the other hand, the Eh values measured in the second monitoring campaign were almost consistent with those measured using the FeS(2)/SO(4)(2-) redox couple. The good fit between the measured Eh values and the theoretical calculated Eh values suggests that the sulfur system is related to the Eh value of sulfidic groundwater in unconsolidated sediments.
  • Takahashi, T, Fujii, K, Igarashi, T, Kakeda, K, Yamada, N
    Jour. Japan Soc. Eng. Geol. 52 (2) 46 - 54 0286-7737 2011/06 [Refereed][Not invited]
  • Sakai, T, Ioka, S, Ishijima, Y, Igarashi, T
    Jour. Japan Soc. Eng. Geol. 52 (1) 2 - 13 0286-7737 2011/04 [Refereed][Not invited]
  • AOKI Takuya, IGARASHI Toshifumi, IIO Yoshihiro, NISHIO Hideaki
    Journal of the Japan Society of Engineering Geology 51 (5) 220 - 228 0286-7737 2010/12 [Refereed][Not invited]
  • Yoshitaka Nara, Toshifumi Igarashi, Naoki Hiroyoshi, Tetsuro Yoneda, Katsuhiko Kaneko
    Zairyo/Journal of the Society of Materials Science, Japan 59 (3) 180 - 185 0514-5163 2010/03 [Refereed][Not invited]
     
    Study of subcritical crack growth is important in estimating the long-term strength of rock and in ensuring the long-term stability of structures in a rock mass. The long-term strength is affected by the value of subcritical crack growth index (SCGI). However, the effect of environmental conditions on SCGI has not been clarified. In this study, we have estimated SCGI under various environmental conditions on a sample of Kumamoto andesite, using the Double-Torsion method. We show that the SCGI decreased when the temperature is higher in both air and water, the SCGI in water is smaller than that in air. When the relative humidity of the air increased, SCGI tended to be smaller and at 90 % relative humidity was close to the value in water. Under alkali conditions, the SCGI decreased slightly. Using the values of SCGI, the long-term strength was estimated and it is shown that the long-term strength decreased when SCGI was smaller. It is concluded that SCGI and the long-term strength is affected by the surrounding environment, specifically by the temperature and water. To ensure the long-term stability of rock, the control of the temperature and water migration is important. © 2010 The Society of Materials Science, Japan.
  • Carlito B. Tabelin, Toshifumi Igarashi, Shuichi Tamoto
    MINERALS ENGINEERING 23 (3) 238 - 248 0892-6875 2010/02 [Refereed][Not invited]
     
    This paper describes the factors affecting arsenic (As) mobility from hydrothermally altered rock under in situ conditions. Four impoundments were built on site with rectangular base, truncated-pyramid structures. Impoundment 1 was composed solely of the hydrothermally altered rock while impoundments 2-4 were covered with different types of silty covering soil in order to minimize O(2) and water intrusion into the rock. The results indicate that seasonal variations in temperature, O(2) concentration and volumetric water content in the impoundments strongly influenced As leaching. When the temperature was high and the water content low, oxidation of sulfide minerals in the rock was enhanced because of a higher air-water-rock interaction. Concentration of As in the porewater increased when it rained after a specific period of dry weather. The use of a silty covering soil influenced the concentrations of As and SO(4)(2-) in the porewater although it did not affect the pH and Eh significantly. In this case, O(2) and water movement might be the rate controlling step of As leaching, that is, if there is no covering soil on the impoundment, more As will leach out from the rock. The use of a silty covering soil showed promise of reducing As leaching from the waste rock, but utilizing it alone was insufficient to effectively prevent As release from the rock. A combination of covering soil and bottom As-adsorption layer to incorporate any As released from the rock is therefore recommended. (C) 2009 Elsevier Ltd. All rights reserved.
  • AOKI Takuya, IGARASHI Toshifumi, IIO Yoshihiro
    Journal of the Japan Society of Engineering Geology 50 (5) 273 - 279 0286-7737 2009/12 [Refereed][Not invited]
     
    Groundwater seepage from a tunnel has been alkaline since it was excavated. Leaching experiments with boring core samples around the tunnel and analysis of the groundwater seepage and surrounding river water were conducted to understand the cause of alkaline water and neutralization processes. In addition, geochemical processes were evaluated by using PHREEQE. The analytical, experimental and calculation results showed that the alkaline groundwater was primarily caused by the dissolution of calcite contained in the shale and sandstone distributed around the tunnel, and that mixing of the al...
  • C. B. Tabelin, T. Igarashi
    JOURNAL OF HAZARDOUS MATERIALS 169 (1-3) 980 - 990 0304-3894 2009/09 [Not refereed][Not invited]
     
    This paper describes the effects of pH, dissolved oxygen (DO), redox conditions, and mixing ratio of different rocks on the leaching behaviors of As and Pb from hydrothermally altered rock as well as the functional groups incorporating As and Pb in the rock. Most of As and Pb were incorporated in the residual or crystalline phase although significant amounts were also determined to be exchangeable, with carbonates and with Fe-Mn oxides. Under oxic conditions,As and Pb showed similar leaching behaviors at similar pH values, a higher mobilization in the acidic and alkaline regions and a minimum at circumneutral pH. The absence of DO restricted the oxidation of sulfide minerals that also contained significant quantities of As resulting in a lower As release under these conditions. Strongly reducing conditions favored the release of As by the reductive dissolution of Fe-Mn oxides and prevention of carbonate precipitation while the same conditions immobilized Pb because of its re-precipitation under reducing conditions. In general, depending on the pH, DO, and redox conditions, the major modes of As and Pb release from these sources could be either one or more of the following mechanisms: acid dissolution, reductive dissolution, ion exchange, desorption and sulfide oxidation processes. (c) 2009 Elsevier B.V. Ail rights reserved.
  • NARA Yoshitaka, TAKADA Masafumi, IGARASHI Toshifumi, HIROYOSHI Naoki, KANEKO Katsuhiko
    Geophysical exploration 物理探査学会 62 (1) 163 - 171 0912-7984 2009/03 [Refereed][Not invited]
  • Yoshitaka Nara, Masafumi Takada, Toshifumi Igarashi, Naoki Hiroyoshi, Katsuhiko Kaneko
    EXPLORATION GEOPHYSICS 40 (1) 163 - 171 0812-3985 2009 [Refereed][Not invited]
     
    Subcritical crack growth is one of the main causes of time-dependent fracturing in rock. In the present study, we investigated subcritical crack growth in rock in distilled water ( pH = 5 7) and in an aqueous solution of sodium hydroxide (NaOHaq, pH = 12), comparing the results to those in air. We also investigated the effect of the pH in an aqueous environment. We used andesite and granite for all our tests. We determined the relationship between the crack velocity and the stress intensity factor using the double-torsion test under conditions of controlled temperature. We showed that crack velocities in water were higher than those in air, in agreement with other research results indicating that crack velocity increases in water. When we compared our results for NaOHaq with those for water, however, we found that the crack velocity at the same stress intensity factor did not change even though the pH of the surrounding environment was different. This result does not agree with the accepted understanding that hydroxide ions accelerate subcritical crack growth in rocks. We concluded that the pH at the crack tip influences subcritical crack growth, and not the bulk pH, which has little effect.
  • T. Igarashi, H. Imagawa, H. Uchiyama, K. Asakura
    MINERALS ENGINEERING 21 (3) 191 - 199 0892-6875 2008/02 [Refereed][Not invited]
     
    Hydrothermally altered igneous rock and mudstone formed under the sea are often rich in arsenic (As). Therefore, As leaching from these rocks excavated during construction work may affect the surrounding soils and groundwater. High-volume, low-concentration contaminants contained in the waste rock as muck have been a major concern in Japan since the Soil Contamination Countermeasures Law was enforced in 2003. The aim of this study is to develop the ways to reduce As concentration leached from muck by controlling the geochemical conditions. Batch leaching experiments were carried out to determine the leaching behavior of As as a function of mixing period, solution pH, oxygen concentration, or mixing ratio of different rocks. The results showed that the As concentration in the leachate approached almost constant after 1-7 days mixing and increased with the As content in the rock, and that the maximum As leaching was observed at around pH 9. The concentration of oxygen gas and the mixing ratio of different rocks also affected the As leaching by changing the leachate pH. This indicates that the solution pH as well as the As content in the rock greatly affects the As leaching from rocks. (c) 2007 Elsevier Ltd. All rights reserved.
  • P. Herrera, H. Uchiyama, T. Igarashi, K. Asakura, Y. Ochi, N. Iyatomi, S. Nagae
    MINERALS ENGINEERING 20 (13) 1255 - 1260 0892-6875 2007/11 [Refereed][Not invited]
     
    A two-step neutralization process, leading to the formation of ferrites has been developed for the treatment of acid mine drainage (AMD). In the first neutralization step magnesium oxide was used to raise the pH to around 4.5 to eliminate aluminium (Al) and to reduce the silica (Si) concentration. In the second neutralization step sodium hydroxide was used to complete the neutralization and to precipitate ferrous and ferric hydroxides, from which ferrite could be formed. The AMD of a closed gold mine in central Hokkaido, Japan was treated in a continuous-flow bench-scale plant of the process. During the first neutralization step the removal of Si was more difficult than the removal of Al; the presence of both At and Si interfered in the ferritization of the sludge. When the Al removal decreased from 94.5% to 64.3% the magnetism per unit mass of the sludge was reduced by 36.7% and when the Al removal decreased to 21.8% the magnetism of the sludge was reduced by 51.5%. The interference of coexisting Si was even stronger: the sludge showed a 26% and 36.7% decrease in magnetism when the removal of Si was reduced by 15% and 18%, respectively. (C) 2007 Elsevier Ltd. All rights reserved.
  • Pepe Herrera S, Hiroyuki Uchiyama, Toshifumi Igarashi, Kuniomi Asakura, Yusuke Ochi, Fumishige Ishizuka, Satoshi Kawada
    MINERALS ENGINEERING 20 (14) 1309 - 1314 0892-6875 2007/11 [Refereed][Not invited]
     
    The acid mine drainage of a closed iron sulphide mine in northern Japan was treated on-site using a continuous flow bench scale plant. In the bench scale plant of the two-step neutralization ferrite-formation process, magnesium oxide or calcium carbonate was used during the first neutralization step to raise the pH to around 4.8 to produce aluminiurn hydroxide sludge. In the second neutralization step sodium hydroxide was applied to reach a pH of 8.5 to produce ferrite sludge. Initial settling rates of the produced aluminium and ferrite sludge were from 1.2 to 4.8 times higher than the initial settling rates of the sludge produced by the treatment plant currently operated at the mine. The suspended solids (SS) concentration in the sludge ranged from 1.0 to 11.8 times higher than the SS concentration in the sludge produced by the current facility. The sludge volume index (SVI) of aluminium sludge was I I and 36 mL/g when produced with magnesium oxide or calcium carbonate, respectively. The SVI of ferrite sludge was 4 mL/g regardless of the type of neutralizer used in the first neutralization, while the same parameter (SVI) of the sludge produced by the current facility is 70 mL/g, which indicates that the two-step neutralization ferrite-formation process generates sludge with much higher density. In addition, the process effectively reduced the concentration of toxic heavy metals from above 800 ppb, 13 ppm, and 15 ppm to as low as 1.4 ppb, 0.02 pprn and 0.2 ppm for arsenic, copper, and zinc, respectively. (c) 2007 Elsevier Ltd. All rights reserved.
  • サロベツ湿原における水文地質特性と植生との関係
    岡野谷哲平, 五十嵐敏文, 朝倉國臣, 平井祐次郎, 石島洋二
    土と基礎 55 (8) 31 - 33 2007/08 [Not refereed][Not invited]
  • IMAGAWA HARUE, IGARASHI TOSHIFUMI, UCHIYAMA HIROYUKI, ASAKURA KUNIOMI
    J MMIJ 123 (4/5) 158 - 164 1881-6118 2007/05 [Refereed][Not invited]
  • IGARASHI Toshifumi, SAITO Ryosuke, SARASHINA Mari, ASAKURA Kuniomi
    Clay Sci 12 (Supplement 2) 143 - 148 0009-8574 2006/04 [Refereed][Not invited]
  • MAHARA YASUNORI, NAKATA EIJI, OYAMA TAKAHIRO, MIYAKAWA KIMIO, IGARASHI TOSHIFUMI, ICHIHARA YOSHIHISA, MATSUMOTO HIROYUKI
    Journal of Groundwater Hydrology 48 (1) 17 - 33 0913-4182 2006/02 [Refereed][Not invited]
  • Kameyama, T, Sakamoto, T, Igarashi, T, Asakura, K
    Journal of Groundwater Hydrology 日本地下水学会 48 (1) 3 - 15 0913-4182 2006/02 [Refereed][Not invited]
  • KAMEYAMA Takahiro, SAKAMOTO Takahiro, IGARASHI Toshifumi, ASAKURA Kuniomi, WAKAHAMA Hiroshi, ISHIJIMA Yoji
    Journal of Groundwater Hydrology 公益社団法人 日本地下水学会 48 (1) 3 - 15 0913-4182 2006 [Not refereed][Not invited]
     
    Wetland is one of the most precious environments. Recently, the natural environment of wetland deteriorates rapidly, due to mainly human activities. The hydrogeological information, however, has not been obtained sufficiently. Therefore, the objective of this study is to clarify the physicochemical and hydrological properties of peat in South Sarobetsu Mire, northern Hokkaido.<BR>Peat samples were taken by means of a peat sampler and a boring. The boring c ore showed that the peat had a thickness of almost 5 m at this point, and that silt and sand layers were overlain by the peat layer. Anisotoropic characteristics of hydraulic conductivity of peat, ranging from 10<SUP>-52</SUP> to 10<SUP>-2</SUP> cm/s, were not observed, whereas the horizontal hydraulic coductivity were larger than the vertical one for the underlain silt and sand layers. Little difference was found in the properties of peat sampled by the above-mentioned two methods. The average sedimentation and degradation rates of the organic carbon in the peat were estimated at 1.2 mm/y and 1.2 x 10<SUP>-4</SUP>y<SUP>-1</SUP> respectively, using the <SUP>14</SUP> C age and vertical profiles of the organic carbon content. This suggests that the age of peat and organic carbon content do not affect its hydrogeological properties in the study area. Therefore, the peat layer can be treated as an aquifer with a representative hydraulic conductivity in the groundwater flow analysis.
  • MAHARA Yasunori, NAKATA Eiji, OOYAMA Takahiro, MIYAKAWA Kimio, IGARASHI Toshifumi, ICHIHARA Yoshihisa, MATSUMOTO Hiroyuki
    Journal of Groundwater Hydrology 公益社団法人 日本地下水学会 48 (1) 17 - 33 0913-4182 2006 [Not refereed][Not invited]
     
    Recently, the interface between freshwate r and seawater in sub-seabed has been discussed actively by using a numerical simulation for construction of huge underground buildings and/or for various wastes disposal in the coastal area. Generally, groundwater flow rate will possibly be small in seawater side behind the interface, and solute transport will be controlled by diffusion phenomena. However, salt-water found in the sub-seabed and a deep stratum has not yet been considerably characterized. Furthermore, there are no criteria and procedures to verify that saltwater behind the interface is not only stagnant but the fossil seawater. In this study, we propose the methodology to characterize it based on information on groundwater residence time using a <SUP>36</SUP>Cl dating method and on groundwater origin from stable isotopes.
  • IGARASHI TOSHIFUMI, SAITO RYOSUKE, NAGASAWA SHUNSUKE, ASAKURA KUNIOMI, KIMURA HIROTOSHI
    Jour. Japan Soc. Eng. Geol. 46 (5) 256 - 264 0286-7737 2005/12 [Refereed][Not invited]
  • NAGASAWA SHUNSUKE, IGARASHI TOSHIFUMI, ASAKURA KUNIOMI, KIMURA HIROTOSHI
    環境工学研究論文集 42 231 - 236 1341-5115 2005/12 [Refereed][Not invited]
  • MARUYAMA Haruka, IGARASHI Toshifumi, ASAKURA Kuniomi, MIYAMAE Hiroko, IYATOMI Nobuyoshi, HASHIMOTO Koichi
    Shigen-to-Sozai 社団法人 資源・素材学会 121 (10/11) 521 - 531 0916-1740 2005/11 [Refereed][Not invited]
     
    To reduce the volume of precipitates generated by the neutralization of acid mine drainage (AMD) containing high concentrations of Fe and As, the formation of ferrite using the precipitates was attempted by a two-step neutralization process in which calcium carbonate (CaCO<SUB>3</SUB>) was used as the first neutralizer and sodium hydroxide (NaOH) as the second. Batch neutralization experiments with CaCO<SUB>3</SUB> and continuous flow experiments by the two-step neutralization were conducted in the laboratory and in an AMD treatment plant. The results showed that the precipitation of Fe, Al...
  • YOSHIDA Tetsuya, IGARASHI Toshifumi, ASAKURA Kuniomi, MIYAMAE Hiroko, IYATOMI Nobuyoshi, HASHIMOTO Koichi
    Shigen-to-Sozai 社団法人 資源・素材学会 120 (10/11) 577 - 583 0916-1740 2004/11 [Refereed][Not invited]
     
    To reduce the volume of precipitates generated by the neutralization of acid mine drainage (AMD) containing high concentrations of Fe and As, ferritization of the precipitates was attempted by a two-step neutralization process in which magnesium oxide (MgO) was used as the first neutralizer and sodium hydroxide (NaOH) as the second. Batch neutralization experiments with MgO and continuous flow experiments by the two-step neutralization were conducted in laboratories and an AMD treatment plant. The results showed that the precipitates by the neutralization were magnetized in the continuous f...
  • Igarashi Toshifumi, Mikami Takashi
    Soil mechanics and foundation engineering 社団法人地盤工学会 52 (9) 22 - 24 0041-3798 2004/09 [Refereed][Not invited]
     
    The excavated rocks from tunnel construction in volcanic areas contain higher heavy metal. Impervious structure using sheet or bentonite is installed to prevent the effluent of the embankment filled with the rocks, although the rationalization is necessary. This study examines use of the clayey soil located near the embankment to reduce the leaching Batch experiments showed that arsenic leaching from crushed altered igneous rocks occurred in two steps, a faster and the subsequent slower one. This indicates that the clayey layer can attenuate the arsenic by its adsorption. This method will b...
  • 長谷川琢磨, 田中靖治, 馬原保典, 五十嵐敏文
    土木学会論文集 (757) 189 - 202 0289-7806 2004/03 [Refereed][Not invited]
  • HASEGAWA Takuma, TANAKA Yasuharu, MAHARA Yasunori, IGARASHI Toshifumi
    Doboku Gakkai Ronbunshu 公益社団法人 土木学会 2004 (757) 189 - 202 2004 [Not refereed][Not invited]
     
    A numerical model based on results during pre-investigation phases was applied to the groundwater flow change caused by the construction of &Auml;sp&ouml; HRL. The drawdowns and chloride concentration during tunnel construction were simulated to validate the numerical model. The groundwater flow was induced by inflow from the Baltic Sea to the tunnel through the hydraulic conductor domain (HCD). The time series of tunnel progress and inflow, boundaries of the Baltic Sea, transmissivity and geometry of HCD are therefore important in representing the groundwater flow. The numerical model roughly represented the groundwater flow during tunnel construction. These simulations were effective in validating the numerical model for groundwater flow and solute transport.
  • IGARASHI TOSHIFUMI, MARUYAMA HARUKA, ASAKURA KUNIOMI, HATTORI SHUICHI
    Jour. Japan Soc. Eng. Geol. 44 (4) 234 - 242 0286-7737 2003/10 [Refereed][Not invited]
  • Y Mahara, T Igarashi
    APPLIED GEOCHEMISTRY 18 (5) 719 - 738 0883-2927 2003/05 [Refereed][Not invited]
     
    The dissolved He content and He isotope ratio are proxy indicators of groundwater evolution in the Shimokita peninsula. The record of H-3 and excess bomb tritiogenic He-3 reveals the intrusion depth of shallow and young groundwater into deep groundwater. The record of tritiogenic 3 He suggests that prior to the period of nuclear testing, the natural production level of H-3 irradiated by cosmic rays was probably 6 TU. Helium isotope ratios in the groundwater converge to that of the regional crustal He with increasing depth and dissolved He content. The regional degassed He has a He-3/He-4 (R) ratio of 7.24 x 10(-7) which consists of 6% mantle He (with R = 1. 1 x 10(-5)) and 94% radiogenic He (with R = 1 x 10(-8)). The magnitude of degassing He flux is 5 x 10(-9) m(3)/m(2) a. Based on the accumulation of He, and taking into consideration the degassing He flux, groundwater at depths greater than 300 m below sea level is estimated to be stagnant, exhibiting residence times in excess of 10(2) Ka. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • Y Mahara, T Igarashi
    APPLIED GEOCHEMISTRY 18 (5) 719 - 738 0883-2927 2003/05 [Not refereed][Not invited]
     
    The dissolved He content and He isotope ratio are proxy indicators of groundwater evolution in the Shimokita peninsula. The record of H-3 and excess bomb tritiogenic He-3 reveals the intrusion depth of shallow and young groundwater into deep groundwater. The record of tritiogenic 3 He suggests that prior to the period of nuclear testing, the natural production level of H-3 irradiated by cosmic rays was probably 6 TU. Helium isotope ratios in the groundwater converge to that of the regional crustal He with increasing depth and dissolved He content. The regional degassed He has a He-3/He-4 (R) ratio of 7.24 x 10(-7) which consists of 6% mantle He (with R = 1. 1 x 10(-5)) and 94% radiogenic He (with R = 1 x 10(-8)). The magnitude of degassing He flux is 5 x 10(-9) m(3)/m(2) a. Based on the accumulation of He, and taking into consideration the degassing He flux, groundwater at depths greater than 300 m below sea level is estimated to be stagnant, exhibiting residence times in excess of 10(2) Ka. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • T Igarashi, R Hataya, T Oyama
    JOURNAL OF GEOCHEMICAL EXPLORATION 77 (2-3) 151 - 165 0375-6742 2003/03 [Refereed][Not invited]
     
    The in situ rate of pyrite oxidation was estimated at a proposed dam site by measurements of the amount of SO42- discharged from the site to evaluate the impact of the dam on the surrounding environment. The 4 concentrations and flows of streams were simultaneously measured. The results showed that the 4 concentration depended on the sampling location, and that the tributaries with high SO42- concentration corresponded to the distribution of pyrite-bearing rocks. The total amount of SO42- discharged at the site was calculated at approximately 7.5 Mg/km(2)/year, based on an integral of the product of the SO42- concentration and stream flow with respect to time. The origins of the discharged SO42- could be divided into two Categories: 60% from pyrite-bearing rocks and 40% from wet deposits at the site. Therefore, the rate of the of pyrite oxidation at the site was calculated to be approximately 2.8 Mg/km(2)/year. The total amounts SO42- discharged from the acid water-producing areas located upstream and downstream of the site were calculated as 13-27 Mg/km(2)/year. The resultant weathering rate was estimated as 0.03-0.28 mm/year by considering the dry density and the pyrite content of these areas. (C) 2002 Elsevier Science B.V. All rights reserved.
  • IGARASHI TOSHIFUMI, IZUTSU TAKAFUMI, OKA YASUMICHI
    Jour. Japan Soc. Eng. Geol. 43 (4) 208 - 215 0286-7737 2002/10 [Refereed][Not invited]
  • Igarashi, T, Oyama, T, Saito, N
    Jour. Japan Soc. Eng. Geol. 42 (4) 214 - 221 0286-7737 2001/04 [Refereed][Not invited]
  • Y Mahara, T Igarashi, T Hasegawa, K Miyakawa, Y Tanaka, K Kiho
    APPLIED GEOCHEMISTRY 16 (3) 291 - 315 0883-2927 2001/03 [Refereed][Not invited]
     
    Hydraulic changes caused by tunneling at the Aspo Hard Rock Laboratory (HRL) in Sweden have been investigated over a period of 2a using different hydrochemical approaches, i.e. noble gas content, isotopic measurements and major ion concentrations. The dissolved noble gases (He-4 and Ne contents, and the ratio of He-3/He-4, Ar-40/Ar-36), Stable isotopes, chemical concentrations of major ions, and Cl-36/Cl ratios, were determined in groundwater samples collected in the tunnel from borehole sections isolated by inflated packers. Groundwater was categorized into 3 groups based on He-4 and Cl- contents: undisturbed groundwater (i.e. prior to tunnel construction) with high He-4 and Cl- contents, groundwater that has been gradually changed by mixing with Baltic seawater and whose He-4 and Cl- contents have gradually increased with increasing depth, and groundwater that has been totally changed due to a rapid mixing of Baltic seawater and/or shallow groundwater and whose He-4 and Cl- contents are extremely low compared with other samples collected at the same surrounding depth. The oldest groundwater with a high salinity of more than 14,000 mg l(-1) of Cl- is estimated to be more than 1.8 Ma old. The groundwater residence time ranges from 0.9 to 900 Ka in the mixing-zone. Groundwater in the disturbed zone where rapid mixing has occurred is hard to date reliably and its primary hydrochemical character has already been lost. (C) 2000 Elsevier Science Ltd. All rights reserved.
  • Hasegawa, T, Igarashi, T, Tanaka, Y, Tsuchi, H, Ono, F
    Journal of groundwater hygrology 43 289 - 300 2001 [Refereed][Not invited]
  • T Igarashi, T Oyama
    ENGINEERING GEOLOGY 55 (1-2) 45 - 55 0013-7952 2000/01 [Refereed][Not invited]
     
    The investigation of water chemistry of a reservoir and the geochemical modeling were carried out to elucidate the deterioration of the water quality. The chemical properties showed that the sulfate ion concentration was high at the sampling locations in the reservoir where the pH value was less than 5, and that there was sufficient dissolved oxygen to keep the redox condition in the reservoir oxic. Reddish-brown iron precipitates were also observed on the surface of the excavated rocks used for the landfill constructed in the center of the reservoir, because the rocks contained an appreciable amount of pyrite. Accordingly, the cause of the reservoir acidification was expected to be the oxidation of pyrite contained in the excavated rocks. The geochemical code, PHRREQE, was applied to evaluate the behavior of aluminum detected in the reservoir. The calculated results showed that the aluminum concentration was restricted by the solubility products of aluminum hydroxides. This suggests that the acidified reservoir water leached aluminum from the surrounding soils, rocks and suspended solids. (C) 1999 Elsevier Science B.V. All rights reserved.
  • T Igarashi, Y Mahara, N Ashikawa, M Okamura
    RADIOCHIMICA ACTA 88 (9-11) 695 - 699 0033-8230 2000 [Refereed][Not invited]
     
    A simple method of evaluating the distribution coefficient (Kd) Of radioactive Ni was examined. The method is based on the measurement of the solid-liquid concentration distribution ratio (fd) Of background stable Ni. To verify the method, the K-d's of both the radioactive Ni and stable Ni were simultaneously measured by using three different samples through batch sorption experiments in which radioactive Ni with a constant concentration and stable Ni with various concentrations coexisted. The f(d) of background stable Ni was then measured by extraction with 0.1N CH3COONH4 and 0.1N HCl solutions to compare f(d) with K-d. The results showed that the K-d's Of radioactive Ni agreed with those of stable Ni, and that the f(d) corresponded to the K-d when the Liquid-phase concentration of stable Ni approached the background level. This indicates that the method of evaluating K-d by using f(d) is applicable to Ni within the experiment.
  • Toshifumi Igarashi, Takahiro Oyama
    Developments in Geotechnical Engineering 84 (C) 247 - 257 0165-1250 2000 [Refereed][Not invited]
     
    The investigation of water chemistry of a reservoir and the geochemical modeling were carried out to elucidate the deterioration of the water quality. The chemical properties showed that the sulfate ion concentration was high at the sampling locations in the reservoir where the pH value was less than 5, and that there was sufficient dissolved oxygen to keep the redox condition in the reservoir oxic. Reddish-brown iron precipitates were also observed on the surface of the excavated rocks used for the landfill constructed in the center of the reservoir, because the rocks contained an appreciable amount of pyrite. Accordingly, the cause of the reservoir acidification was expected to be the oxidation of pyrite contained in the excavated rocks. The geochemical code, PHRREQE, was applied to evaluate the behavior of aluminum detected in the reservoir. The calculated results showed that the aluminum concentration was restricted by the solubility products of aluminum hydroxides. This suggests that the acidified reservoir water leached aluminum from the surrounding soils, rocks and suspended solids. © 2000 Elsevier B.V. All rights reserved.
  • IGARASHI TOSHIFUMI, SHIMOGAKI HISASHI
    地下水学会誌 40 (2) 121 - 132 0913-4182 1998/05 [Refereed][Not invited]
  • 五十嵐 敏文, 下垣 久
    地下水学会誌 日本地下水学会 40 (2) 121 - 132 0913-4182 1998/05 [Not refereed][Not invited]
  • T Igarashi, Y Mahara, N Ashikawa, M Okamura
    JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 35 (3) 190 - 197 0022-3131 1998/03 [Not refereed][Not invited]
     
    A new method of evaluating the distribution coefficient (K-d) of radioactive Sr was examined. The method is based on the measurement of the solid-liquid concentration distribution ratio (R-d) of background stable Sr. To verify the method, the K-d's of both the radioactive Sr and stable Sr were simultaneously measured by batch sorption experiments in which radioactive Sr with a constant concentration and stable Sr with various concentrations coexisted. The R-d of background stable Sr was then measured by extraction with 0.1N CH3COONH4 and 0.1N HCl solutions to compare R-d with K-d. The results showed that the K-d's of radioactive Sr agreed with those of stable Sr, and that the R-d corresponded to the K-d when the liquid-phase concentration of stable Sr approached the background level. This indicates that the new method of evaluating K-d by using R-d is applicable to Sr.
  • IGARASHI TOSHIFUMI, OYAMA TAKAHIRO
    応用地質 38 (5) 244 - 251 0286-7737 1997/12 [Refereed][Not invited]
  • MAHARA YASUNORI, IGARASHI TOSHIFUMI, TANAKA YASUHARU
    地下水学会誌 35 (3) 201 - 215 0913-4182 1993/08 [Refereed][Not invited]
  • T IGARASHI
    JOURNAL OF THE ATOMIC ENERGY SOCIETY OF JAPAN 35 (3) 237 - 244 0004-7120 1993/03 [Refereed][Not invited]
     
    The migration of Co through a saturated sand layer was investigated by a column method. Cobalt breakthrough curves and adsorbed Co concentration profiles in the sand layer were measured. The results showed that, under weakly-alkaline conditions, Co adsorption by sand resulted from the reaction between hydrolyzed Co and sand (irreversible adsorption), as well as from the ion exchange between ionic Co and exchangeable cations such as Ca and Mg on the surface of sand (reversible adsorption). Under acidic conditions, the Co adsorption simply resulted from the ion exchange. These two mechanisms were evaluated with equilibrium ion-exchange reactions between Co, Ca and Mg, and a first-order irreversible reaction with respect to the Co concentration. The selectivity coefficient, which is the reversible ion-exchange parameter, and the first-order rate constant, which is the irreversible adsorption parameter, were constant independent of coexisting Ca concentration and the length of sand column when solution pH was unchanged.
  • IGARASHI TOSHIFUMI, UMAHARA YASUNORI, OKAMURA MASANORI, ASHIKAWA NOBUO
    Radioisotopes 41 (7) 350 - 356 0033-8303 1992/07 [Refereed][Not invited]
  • IGARASHI TOSHIFUMI, SHIMOGAKI HISASHI
    水工学論文集 36 397 - 402 0916-7374 1992/02 [Refereed][Not invited]
  • T IGARASHI, Y MAHARA, M KAWANISHI, Y FUJIWARA, S IMAMURA, M SHIMO
    JOURNAL OF THE ATOMIC ENERGY SOCIETY OF JAPAN 33 (2) 180 - 193 0004-7120 1991 [Refereed][Not invited]
     
    To evaluate the characteristics of groundwater flow and nuclide migration through unsaturated loamy soil, various field tracer experiments have been carried out using both nonreactive tracers (D2O, Br-) and reactive tracers (Sr, Co, Cs). The present paper discusses the migration characteristics of reactive tracers under the direct influence of natural rainfall and evapotranspiration. The infiltration rates of reactive tracers such as Sr, Co and Cs were smaller than those of nonreactive tracers. Particularly, most of injected Cs remained near the tracer injection plane, i.e. the ground surface. The retardation phenomenon was caused by the adsorption of reactive tracers by loamy soil. The temporal and spatial variation of the distribution coefficient (Kd(r)) of reactive tracers obtained by field experiment ranged from 10(-2) to 10(2) ml/g. This widely dispersed Kd(r) value showed dependency on the concentration of the tracer itself and coexisting cation. The Kd(r) value obtained by the field experiment was consistent with that obtained by the batch experiment considering the concentration dependency. In addition, the selectivity coefficients of reactive tracers were almost constant with respect to coexisting Ca, and this indicates that the adsorption of reactive tracers mainly resulted from ion exchange reaction.
  • T IGARASHI, Y MAHARA, M KAWANISHI, Y FUJIWARA, S IMAMURA, M SHIMO
    JOURNAL OF THE ATOMIC ENERGY SOCIETY OF JAPAN Atomic Energy Society of Japan 33 (2) 180 - 193 0004-7120 1991 [Not refereed][Not invited]
     
    To evaluate the characteristics of groundwater flow and nuclide migration through unsaturated loamy soil, various field tracer experiments have been carried out using both nonreactive tracers (D2O, Br-) and reactive tracers (Sr, Co, Cs). The present paper discusses the migration characteristics of reactive tracers under the direct influence of natural rainfall and evapotranspiration. The infiltration rates of reactive tracers such as Sr, Co and Cs were smaller than those of nonreactive tracers. Particularly, most of injected Cs remained near the tracer injection plane, i.e. the ground surface. The retardation phenomenon was caused by the adsorption of reactive tracers by loamy soil. The temporal and spatial variation of the distribution coefficient (Kd(r)) of reactive tracers obtained by field experiment ranged from 10(-2) to 10(2) ml/g. This widely dispersed Kd(r) value showed dependency on the concentration of the tracer itself and coexisting cation. The Kd(r) value obtained by the field experiment was consistent with that obtained by the batch experiment considering the concentration dependency. In addition, the selectivity coefficients of reactive tracers were almost constant with respect to coexisting Ca, and this indicates that the adsorption of reactive tracers mainly resulted from ion exchange reaction.
  • IGARASHI TOSHIFUMI
    衛生工学研究論文集 26 97 - 105 0913-4069 1990/01 [Refereed][Not invited]
  • T IGARASHI, Y MAHARA, M KAWANISHI, Y FUJIWARA, S IMAMURA, M SHIMO
    JOURNAL OF THE ATOMIC ENERGY SOCIETY OF JAPAN 32 (12) 1232 - 1242 0004-7120 1990 [Refereed][Not invited]
     
    To evaluate the characteristics of groundwater flow and nuclide migration through unsaturated loamy soil, various field tracer experiments have been carried out using both nonreactive tracers (D2O, Br-) and reactive tracers (Co, Sr, Cs). This paper discusses the migration characteristics of nonreactive tracers under the direct influence of natural rainfall and evapotranspiration. D2O was a more conservative tracer than Br- ion to evaluate an unsaturated flow because the infiltration rate of Br- ion was slower than that of D2O owing to anion adsorption of allophane, a major mineral in loamy soil. The longitudinal and transverse dispersion coefficients were calculated from the spatial distributions of D2O concentration. The linear relation between the maximum concentration depth of D2O and the cumulative rainfall indicates that the rainfall gives a significant influence on the infiltration rate while the evapotranspiration gives little influence.
  • T IGARASHI, Y MAHARA, M KAWANISHI, Y FUJIWARA, S IMAMURA, M SHIMO
    JOURNAL OF THE ATOMIC ENERGY SOCIETY OF JAPAN Atomic Energy Society of Japan 32 (12) 1232 - 1242 0004-7120 1990 [Not refereed][Not invited]
     
    To evaluate the characteristics of groundwater flow and nuclide migration through unsaturated loamy soil, various field tracer experiments have been carried out using both nonreactive tracers (D2O, Br-) and reactive tracers (Co, Sr, Cs). This paper discusses the migration characteristics of nonreactive tracers under the direct influence of natural rainfall and evapotranspiration. D2O was a more conservative tracer than Br- ion to evaluate an unsaturated flow because the infiltration rate of Br- ion was slower than that of D2O owing to anion adsorption of allophane, a major mineral in loamy soil. The longitudinal and transverse dispersion coefficients were calculated from the spatial distributions of D2O concentration. The linear relation between the maximum concentration depth of D2O and the cumulative rainfall indicates that the rainfall gives a significant influence on the infiltration rate while the evapotranspiration gives little influence.
  • 丹保 憲仁, 五十嵐 敏文, 清塚 雅彦
    水道協会雑誌 日本水道協会 54 (1) 2 - 6 0371-0785 1985/01 [Not refereed][Not invited]

MISC

  • Tabelin Carlito, Sasaki Asuka, Igarashi Toshifumi, Tomiyama Shingo, Villacorte-Tabelin Mylah, Ito Mayumi, Hiroyoshi Naoki  25TH REGIONAL SYMPOSIUM ON CHEMICAL ENGINEERING (RSCE 2018)  268-  2019  [Refereed][Not invited]
  • 畠 俊郎, 五十嵐 敏文, 新藤 和男, 辰巳 健一  地盤工学会誌 = Geotechnical engineering magazine : 土と基礎  66-  (8)  76  -83  2018/08  [Not refereed][Not invited]
  • Elakneswaran Yogarajah, Toyoharu Nawa, Toshifumi Igarashi  MATEC Web of Conferences  147-  2018/01/22  [Refereed][Not invited]
     
    A partial replacement of Portland cement (PC) by ground granulated blast furnace slag (GGBFS) is an effective method to improve the durability of concrete due to its lower diffusivity and higher chemical resistance compared to PC. Further, the microstructure of GGBFS blended cementitious materials controls the physicochemical properties and performance of the materials in concrete. Therefore, understanding of cement hydration and cementing behavior of GGBFS is essential to establish microstructure property relationship for predicting performance. In this study, hydration, microstructure development, and chloride ingress into GGBFS-blended cement have been investigated. Solid-phase assemblage and pore solution chemistry of hydrating PC and cement blended with GGBFS were predicted using thermodynamic model and compared with experimental data. A mathematical model integrating PC hydration, GGBFS reaction, thermodynamic equilibrium between hydration products and pore solution, ionic adsorption on C-S-H, multi-component diffusion, and microstructural changes was developed to predict chloride ingress into GGBFS blended cementitious materials. The simulation results on chloride profiles for hydrated slag cement paste, which was prepared with 50% of replacement of PC with GGBFS, were compared with experimental results. The model quantitively predicts the states of chloride such as free, adsorbed on C-S-H, and chemically bound as Friedel's salt.
  • The roles of soluble phases in the release of geogenic arsenic and selenium from tunnel-excavated rocks of marine origin
    C.B. Tabelin, R. Sasaki, T. Igarashi, I. Park, S. Tamoto, T. Arima, M. Ito, N. Hiroyoshi  Proc. of the 17th Global Joint Seminar on Geo-environmental Engineering,  312  -319  2018  [Not refereed][Not invited]
  • Enhanced passivation of pyrite in phosphate solution using ferric-catechol complex and zero-valent iron
    C.B. Tabelin, X. Li, S. Seng, M. Kojima, T. Igarashi, M. Ito, N. Hiroyoshi  the 14th International Symposium on East Asian Resources Recycling Technology and the Mining and Materials Processing Institute of Japan Fall Meeting  8  -13  2017  [Not refereed][Not invited]
  • 五十嵐 敏文  地盤工学会誌 = Geotechnical engineering magazine : 土と基礎  64-  (11)  52  -57  2016/11  [Not refereed][Not invited]
  • 石神 大輔, 渡辺 哲哉, 五十嵐 敏文, 田村 拓四郎, 田作 淳, 土光 政伸  地下水・土壌汚染とその防止対策に関する研究集会講演集  22-  28  -33  2016/06/23  [Not refereed][Not invited]
  • Tomoko Ohta, Yasunori Mahara, Satoshi Fukutani, Takumi Kubota, Hiroyuki Matsuzaki, Yuji Shibahara, Toshifumi Igarashi, Ryoko Fujiyoshi, Naoko Watanabe, Tamotsu Kozaki  Radiological Issues for Fukushima's Revitalized Future  13  -24  2016/01/01  [Not refereed][Not invited]
     
    We evaluated the migration of radionuclides (131I, 129I, 134Cs, 136Cs, 137Cs, and 132Te) in the surface soil after the Fukushima nuclear accident. The radionuclides in the soil collected late March in 2011 were barely leached with ultrapure water, indicating that these are insoluble. We observed the chemical behavior of 137Cs and 129I in soil: (1) 137Cs was predominantly adsorbed within a depth of 2.5 cm from the ground surface (2) 137Cs was hardly released from soil by the water leaching experiments that lasted for 270 days (3) approximately, more than 90 % of 137Cs was adsorbed on organic matters and the residual fractions, while 129I was mainly fixed on the Fe-Mn oxide and organically bounded fraction. Therefore, we conclude that 137Cs and 129I in soil seldom leach into the soil water and migrate downward because of the irreversible adsorption. The shallow groundwater which residence time is short.
  • Electrochemical insights on pyrite dissolution in the presence of alumina
    S. Veerawattananun, D. Wiwattanadate, C.B. Tabelin, M. Ito, N. Hiroyoshi, T. Igarashi  the 9th International Conference on Earth Resources Technology  906  -917  2016  [Not refereed][Not invited]
  • Suppression of arsenopyrite oxidation by carrier microencapsulation using Ti-catechol complex.
    I. Park, K. Magaribuchi, S. Veerawattananum, C.B. Tabelin, M. Ito, N. Hiroyoshi, T. Igarashi  the 9th International Conference on Earth Resources Technology,  918  -928  2016  [Not refereed][Not invited]
  • Fundamental electrochemical studies of carrier micro-encapsulation on pyrite: The stability of metal-organic complexes
    S. Veerawattananun, D. Wiwattanadate, C.B. Tabelin, M. Ito, N. Hiroyoshi, T. Igarashi  Proceedings of the 15th Japan-Korea-France-Canada Joint Seminar on Geo-environmental Engineering,  141  -150  2016  [Not refereed][Not invited]
  • The interplay between pyrite and hematite and its implications in acid mine drainage control
    C.B. Tabelin, S. Veerawattananum, M. Ito, N. Hiroyoshi, T. Igarashi  Proceedings of the 15th Japan-Korea-France-Canada Joint Seminar on Geo-environmental Engineering  141  -150  2016  [Not refereed][Not invited]
  • 石神 大輔, 渡辺 哲哉, 五十嵐 敏文  地下水・土壌汚染とその防止対策に関する研究集会講演集  21-  125  -130  2015/06/18  [Not refereed][Not invited]
  • Elucidation of the Uptnke Route of Radionuclides in Deciduous and
    T. Ohta, T. Kubota, Y. Shibahara, S. Fukutani, T. Fujii, T. Igarashi, Y. Mahara  KURRI Progress Report  64  -64  2015  [Not refereed][Not invited]
  • 窪田卓見, 太田朋子, 馬原保典, 五十嵐敏文  KURRI-KR  (200)  56  -58  2015/01  [Not refereed][Not invited]
  • Migration of 137Cs from fukushima daiichi nuclear power plant in kanto loam soil
    T. Kubota, T. Ohta, Y. Mahara, T. Igarashi  Proceedinngs of 49th KURRI Scientific Meeting  56  -58  2015/01  [Not refereed][Not invited]
  • Sequestration of boron, arsenic and selenium leached from tunnel-excavated rocks through adsorption
    C.B. Tabelin, A. Hashimoto, T. Igarashi, M. Ito, N. Hiroyoshi  Proc. of the 14th Global Joint Seminar on Geo-environmental Engineering  5  2015  [Not refereed][Not invited]
  • The effects of colloidal α-Fe2O3 on pyrite oxidative dissolution and their implications in the formation of acid mine drainage
    C.B. Tabelin, N. Hiroyoshi, M. Ito, T. Igarashi  Proc. of the 8th International Conference on Geological and Geo-resources Engineering and 7th Mineral Symposium  17  2015  [Not refereed][Not invited]
  • Acid Mine Drainage: Sources, environmental impacts and mitigation approaches
    C.B. Tabelin, M, Ito, N. Hiroyoshi, T. Igarashi  Proc. of the 2nd International Symposium Integrated Research and Education Center for Energy Conversion, Storage, Saving, and Transport Technologies,  13  -14  2015  [Not refereed][Not invited]
  • TATSUHARA Takeshi, JIKIHARA Shunsuke, TATSUMI Takakuni, IGARASHI Toshifumi  Japanese Geotechnical Journal  10-  (4)  635  -640  2015  [Not refereed][Not invited]
     
    An adsorption layer system to immobilize hazardous heavy metals and metalloids, such as lead (Pb), arsenic (As), and selenium (Se), leached from excavated natural rocks has been selected recently. The adsorption layer can reasonably be designed by considering the risk of toxic elements to the surrounding environment. In addition, the layout of the adsorption layer can be designed depending on the topographical and/or hydrogeological conditions of the site. In this study, we examined the effective layout of the adsorption layer by column experiments with different packing configurations. The results showed that the bottom adsorption layer had the highest amount of arsenic adsorbed released from mudstones. This indicates that the adsorption layer should be placed undermost, also by considering the scheme of construction.
  • OTA TOMOKO, KUBOTA TAKUMI, MAHARA YASUNORI, IGARASHI TOSHIFUMI  日本海水学会誌  68-  (3)  165  2014/06/01  [Not refereed][Not invited]
  • Leachability of arsenic from tunnel-excavated rock under free- and controlled-flow conditions,
    C.B. Tabelin, T. Igarashi, M. Ito, N. Hiroyoshi  Proc. of the 13th Global Joint Seminar on Geo-Environmental Engineering,  31  -37  2014  [Not refereed][Not invited]
  • The leaching and speciation behaviors of arsenic and selenium in tunnel-excavated rocks under flow-through conditions,
    C.B. Tabelin, R. Sasaki, T. Igarashi, S. Tamoto, M. Ito, N. Hiroyoshi  Proc. of the 3rd International Conference on Advances in Mining and Tunneling  573  -581  2014  [Not refereed][Not invited]
  • Enhanced encapsulation of pyrite using colloidal “micro-seeds”: Visualization and attachment experiments,
    C.B. Tabelin, N. Hiroyoshi, M. Ito, T. Igarashi  Proc. of the 7th AUN/SEED-Net Geological Engineering Conference and the 2nd AUN/SEED-Net Natural Disaster Conference,  20  2014  [Not refereed][Not invited]
  • Tunnel-excavated rock: An invisible threat to the environment,
    C.B. Tabelin, T. Igarashi, M. Ito, N. Hiroyoshi  Proc. of the 8th Asian Rock Mechanics Symposium  2554  -2560  2014  [Not refereed][Not invited]
  • 五十嵐 敏文, 龍原 毅, 堀内 康光, 佐藤 明, 新藤 和男, 平本 弘  地盤工学会誌  62-  (8)  2014  [Not refereed][Not invited]
  • Tomoko Ohta, Yasunori Mahara, Takumi Kubota, Toshifumi Igarashi  ANALYTICAL SCIENCES  29-  (12)  1230  -1230  2013/12  [Not refereed][Not invited]
  • 佐々木明日香, 五十嵐敏文  環境地盤工学シンポジウム発表論文集  10th-  125  -130  2013/09/17  [Not refereed][Not invited]
  • MAHARA YASUNORI, OTA TOMOKO, IGARASHI TOSHIFUMI  J MMIJ  129-  (6)  261  -269  2013/06/01  [Not refereed][Not invited]
  • 五十嵐 敏文, 原田 周作, 太田 朋子  電力土木 = Electric power civil engineering  0-  (360)  126  -128  2012/07  [Not refereed][Invited]
  • TAMAMURA SHUJI, SAKAI TOSHIAKI, SHIMIZU SATORU, ISHIJIMA YOJI, IGARASHI TOSHIFUMI  地下水学会誌  54-  (2)  107  -116  2012/05  [Refereed][Not invited]
  • 五十嵐 敏文  化学物質と環境 : 化学物質と環境との調和をめざす情報誌  (113)  5  -7  2012/05  [Not refereed][Invited]
  • 関東地方に降下した放射性核種の降下量の測定と関東ローム層から土壌水への移行挙動の観測
    太田朋子, 馬原保典, 窪田卓見, 藤原慶子, 福谷哲, 高宮幸一, 小池裕也, 五十嵐敏文  第13回「環境放射能」研究会  2012/02  [Not refereed][Not invited]
  • Sakai Toshiaki, Igarashi Tohsifumi  研究発表会講演論文集  24-  45  -46  2012  [Not refereed][Not invited]
  • ITO Mayumi, HIROYOSHI Naoki, IGARASHI Toshifumi  工学教育研究講演会講演論文集  23-  (59)  620  -621  2011/08/22  [Not refereed][Not invited]
  • 伊東佳彦, 日下部祐基, 岡崎健治, 田本修一, 中川伸一, 五十嵐敏文  土木研究所共同研究報告書  (420)  28P  2011/04  [Not refereed][Not invited]
  • OTA TOMOKO, MAHARA YASUNORI, KUBOTA TAKUMI, FUKUTANI SATOSHI, MIZUOCHI YUKIHIRO, IGARASHI TOSHIFUMI  日本地下水学会講演会講演要旨  2011-  110  -113  2011  [Not refereed][Not invited]
  • OTA TOMOKO, KUBOTA TAKUMI, MAHARA YASUNORI, FUKUTANI SATOSHI, FUJIWARA KEIKO, IGARASHI TOSHIFUMI  日本原子力学会北海道支部研究発表会講演要旨集  29th-  29  -30  2011  [Not refereed][Not invited]
  • Journal of Japan Society of Engineering Geology  52-  (3)  88  -96  2011  [Not refereed][Not invited]
  • Journal of Japan Society of Engineering Geology  52-  (2)  46  -54  2011  [Not refereed][Not invited]
  • Journal of Japan Society of Engineering Geology  52-  (1)  2  -13  2011  [Not refereed][Not invited]
  • IOKA SEIICHIRO, SAKAI TOSHIAKI, IGARASHI TOSHIFUMI, ISHIJIMA YOJI  地下水学会誌  52-  (2)  195  -204  2010/05  [Refereed][Not invited]
  • IOKA Seiichiro, SAKAI Toshiaki, IGARASHI Toshifumi, ISHIJIMA Yoji  Suimontishitukenkyukaikaisi  52-  (2)  205  -210  2010  [Not refereed][Not invited]
  • Y. Nara, T. Igarashi, N. Hiroyoshi, T. Yoneda, K. Kaneko  72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010  6-  4386  -4390  2010/01/01  [Not refereed][Not invited]
     
    Long-term stability is required for the structures in a rock mass. Especially, the estimation of long-term strength of rock is essential to consider the long-term stability. In this study, we investigated the time-dependent crack growth in rock. Specifically, subcritical crack growth in water and in air with different relative humidities was measured in order to investigate the effect of water on the value of subcritical crack growth index and the long-term strength for rock. It was shown that subcritical crack growth index in water was smaller than that in air. Additionally, subcritical crack growth index tended to be smaller when the relative humidity was higher. The long-term strength in water was smaller than that in air. In air, the long-term strength tended to be smaller when the relative humidity was higher. The long-term strength is larger when subcritical crack growth index is larger. For the long-term stability, it is thus important to achieve a condition where subcritical crack growth index becomes larger. It is concluded that retarding the migration of water into and through rock and keeping low humidity is important. © 2010, European Association of Geoscientists and Engineers.
  • 嘉門雅史, 脇坂安彦, 駒井武, 五十嵐敏文, 奥村興平, 勝見武, 佐々木靖人, 丸茂克美, 井上千弘, 佐々木哲也, 杉田秀樹, 三田村宗樹, 伊東佳彦, 太田岳洋, 足立晃一, 木暮敬二, 木幡邦男, 高澤哲也, 東川直正, 野田勝, 品川俊介, 森啓年, 乾徹, 田本修一, 阿南修司, 浅井健一, 須藤孝一, 亀和田俊一, 川辺能成, 龍原毅, 保賀康史  土木研究所資料  (4156)  152P  2010/01  [Not refereed][Not invited]
  • Journal of Japan Society of Engineering Geology  51-  (5)  220  -228  2010  [Not refereed][Not invited]
  • Yoshitaka NARA, Toshifumi IGARASHI, Naoki HIROYOSHI, Tetsuro YONEDA, Katsuhiko KANEKO  Journal of the Society of Materials Science, Japan  59-  (3)  180  -185  2010  [Not refereed][Not invited]
  • 岩盤掘削ずりからの重金属溶出特性に基づく対策法の構築へ向けて
    五十嵐 敏文  第8回環境地盤工学シンポジウム発表論文集  8-  1  -6  2009/07  [Not refereed][Invited]
  • Journal of Japan Society of Engineering Geology  50-  (5)  273  -279  2009  [Not refereed][Not invited]
  • Toward to establishing countermeasures against heavy metals leaching from excavated rocks
    Proceedings of the 8th symposium of geoenvironmental engineering  8-  1  -6  2009  [Not refereed][Not invited]
  • 五十嵐 敏文  いんだすと  23-  (12)  11  -14  2008/12  [Not refereed][Not invited]
  • 五十嵐敏文  いんだすと  23-  (12)  11  -14  2008/12  [Not refereed][Invited]
  • 五十嵐敏文  日本応用地質学会特別講演およびシンポジウム予稿集  2008-  20  -27  2008/05  [Not refereed][Invited]
  • 五十嵐 敏文  学士会会報  2008-  (2)  43  -47  2008/03  [Refereed][Not invited]
  • Relationship between Hydrogeological Properties and Vegetation in Sarobetsu Mire
    Tsuchi-To-Kiso  55-  (8)  31  -33  2007  [Not refereed][Not invited]
  • Journal of MMIJ  123-  (4)  5,158-164  2007  [Not refereed][Not invited]
  • Igarashi, T, Yoshida, T, Asakura, K, Miyamae, H, Iyamoto, N, Hashimoto, K  5th ICEG Environmental Geotechnics  II-  (2)  909  -916  2006/12/01  [Refereed][Not invited]
     
    Ferrite formation in precipitates by a two-step neutralization process in which magnesium oxide (MgO) was used as the first neutralizer and sodium hydroxide (NaOH) as the second was applied to acid mine drainage (AMD) from the Horobetsu mine, an abandoned sulfur mine, in Hokkaido, Japan, to reduce the volume of precipitates to be disposed. Batch neutralization experiments with MgO and continuous flow experiments by the two-step neutralization were conducted in the laboratory and the actual AMD treatment plant. The results showed that the heavy metals in the AMD were successfully removed by the process, and that the precipitates were magnetized by the neutralization in the continuous flow experiments although there was Al and Si in the AMD that could have prevented the formation of ferrite. This indicates that ferrite can be formed from the precipitates after removing most of the soluble Al and Si by the first neutralization. The change in the chemical forms of the iron precipitates and preventing gypsum and calcite formation in the precipitates by MgO result in a volume reduction of precipitates by two thirds for this AMD when compared with conventional processes.
  • 五十嵐 敏文  地質と調査  2006-  (2)  20  -24  2006  [Not refereed][Invited]
  • SAKAMOTO Takahiro, KAMEYAMA Takahiro, IGARASHI Toshifumi, ASAKURA Kuniomi, WAKAHAMA Hiroshi, ISHIJIMA Yoji  Doboku Gakkai Ronbunshuu G  13-  335  -340  2005  [Not refereed][Not invited]
     
    Fixation of CO<SUB>2</SUB> by peat in the South Sarobetsu mire was estimated based on the rate of accumulation of peat. Carbon-14 in the remains of plants in the peat layer was measured for dating. The results showed that the thickness of the peat layer was from 2.7 to 4.5m, and that the rate of accumulation of the layer was 0.95 to 1.15m/y. The CO<SUB>2</SUB> accumulation rate in the mire was estimated at 34, 000tons/yr by considering the physical and chemical properties of the peat and the accumulation rate.
  • Haruka MARUYAMA, Toshifumi IGARASHI, Kuniomi ASAKURA, Hiroko MIYAMAE, Nobuyoshi IYATOMI, Koichi HASHIMOTO  Journal of MMIJ  121-  (10/11)  521  -531  2005  [Not refereed][Not invited]
  • Toshifumi IGARASHI, Ryosuke SAITO, Shunsuke NAGASAWA, Kuniomi ASAKURA, Hirotoshi KIMURA  Journal of Japan Society of Engineering Geology  46-  (5)  256  -264  2005  [Not refereed][Not invited]
  • Journal of MMIJ  120-  (10/11)  577  -583  2004  [Not refereed][Not invited]
  • Utilization of surrounding clayey soil as sealing materials for mucks rich in heavy metal
    Tsuchi-To-Kiso  52-  22  -24  2004  [Not refereed][Not invited]
  • Validation of groundwater flow model using the change of groundwater flow caused by the construction of Aspo Hard Rock Laboratory
    Journals of the Japan Society of Civil Engineers  757-  (III-60)  189  -202  2004  [Not refereed][Not invited]
  • Journal of Japan Sociert of Engineering Geology  44-  (4)  234  -242  2003  [Not refereed][Not invited]
  • 五十嵐 敏文  資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan  118-  (12)  760  -761  2002/12  [Not refereed][Not invited]
  • Numerical analysis for tracer migration experiments aiming at a single fracture in cristalline rock
    Tanaka, Y, Miyakawa, K, Hasegawa, T, Igarashi, T  The 11th Japan National Symposium for Rock Mechanics 2002  G06  2002  [Refereed][Not invited]
  • Numerical analysis for tracer migration experiments aiming at a single fracture in crystalline rock
    The 11th Japan National Symposium for Rock Mechanics 2002  G06  2002  [Not refereed][Not invited]
  • Toshifumi IGARASHI, Takafumi IZUTSU, Yasumichi OKA  Journal of Japan Society of Engineering Geology  43-  (4)  208  -215  2002  [Not refereed][Not invited]
  • Acidification potential of leachate from altered igneous rocks containing pyrite
    The 11th Japan National Symposium for Rock Mechanics 2002  D02  2002  [Not refereed][Not invited]
  • IGARASHI TOSHIFUMI, OYAMA TAKAHIRO, HATAYA RYUTA  The 11th Japan Symposium on Rock Mechanics 2002  11th-  (Pt.1)  221  -226  2001/12  [Refereed][Not invited]
  • Hydraulic conductivity and migration characteristics of low-permeable rocks II: Solute migration through a single fracture
    CRIEPI Report  U00011-  1  -11  2001  [Not refereed][Not invited]
  • Toshifumi IGARASHI, Takahiro OYAMA, Noriyuki SAITO  Journal of JapanSociety of Enginerring Geology  42-  (4)  214  -221  2001  [Not refereed][Not invited]
  • Japanese Association of Groundwater Hydrology  43-  289  -300  2001  [Not refereed][Not invited]
  • 五十嵐敏文, 馬原保典, 塩崎功  地下水学会誌  42-  (3)  243  -262  2000/08  [Refereed][Not invited]
  • 五十嵐敏文, 中沢俊之, 上田真三  KURRI KR  (44)  177  -182  2000/02  [Not refereed][Not invited]
  • 「廃棄物処分・環境安全用語辞典」
    丸善  2000  [Refereed][Invited]
  • 2成分溶出モデルによる黄鉄鉱からの鉄および硫酸イオンの溶出挙動評価
    岡 泰道, 五十嵐敏文, 井筒崇文, 岡泰道  土木学会第54回年次学術講演会講演概要集第Ⅶ部  584  -585  1999  [Not refereed][Not invited]
  • Igarashi Toshifumi, Tsukamoto Masaki, Fujiwara Hiroshi, Ueda Hiroyoshi, Ikeda Takao, Saito Shigeyuki  Journal of Nuclear Fuel Cycle and Environment  5-  (2)  169  -197  1999  [Not refereed][Not invited]
     
    Scenarios for the geological disposal of high-level wastes were constructed in order to assess the safety of the HLW disposal and the performance of the repositories. The list of features, events, and processes (FEP) related to the disposal and their influence on others, called process influence diagram (PID), were utilized to construct the scenarios. As a result, the scenario involved in groundwater flow can be divided into a reference scenario and alternative scenarios. In addition, the latter are composed of upheaval/erosion, submergence, permanent glacial epoch, permanent interglacial epoch, and higher-temperature inclination with depth. According to the scenario analysis, the performance assessments of barriers were conducted for a sedimentary rock area and granitoid rock area. The results showed that a lower individual dose resulting from the disposal was obtained for the sedimentary rock area because of the higher values of porosity and distribution coefficients in the sedimentary rock area than those in the granitoid rock area. In addition, the dose for the upheaval/erosion scenario gave rise to the highest value.
  • 五十嵐 敏文, 大山 隆弘, 井筒 崇文  衛生工学シンポジウム論文集  6-  (0)  179  -182  1998/11  [Not refereed][Not invited]
     
    第6回衛生工学シンポジウム(平成10年11月5日(木)-6日(金) 北海道大学学術交流会館) . 5 測定・解析 . P5-7
  • Igarashi Toshifumi, Kiho Kenzo  Journal of Nuclear Fuel Cycle and Environment  4-  (1)  67  -72  1997  [Not refereed][Not invited]
     
    An operational phase of Äspö Hard Rock Laboratory international project was started in 1995. Two different types of in situ experiments, i.e., experiments for description of the barrier function of host rock and for demonstration of the function of important parts of a repository system, are being carried out and/or planned. The former consists of groundwater flow and tracer migration experiments in a single fracture called TRUE, redox experiment in the detailed scale called REX, arid in situ column experiment by CHEMLAB called RNR. The latter consists of backfill and plug test, long term performance tests of bentonite as buffer material, and construction of prototype repository. This paper describes the status and the research plans of the Äspö HRL project during the operational phase and CRIEPIs contribution to the project as well.
  • IGARASHI Toshifumi  Journal of the Atomic Energy Society of Japan / Atomic Energy Society of Japan  38-  (4)  272  -278  1996/04  [Refereed][Not invited]
  • T Igarashi  JOURNAL OF THE ATOMIC ENERGY SOCIETY OF JAPAN  38-  (4)  272  -278  1996  [Not refereed][Not invited]
     
    An underground laboratory must be built for research and development related to the geological disposal of high-level radioactive wastes. Swedish Nuclear Fuel and Waste Management Company (SKB) started pre-investigations for building an underground laboratory, the Aspo Hard Rock Laboratory (Aspo HRL), in southeastern Sweden in 1986, and has just initiated several in situ experiments in the laboratory. In situ experiments consist of redox experiments, an excavation disturbance experiment, a pore-volume characterization experiment, tracer experiments in a single fracture, an in situ column experiment, and a two-phase flow experiment. Other experiments related to the design and construction of a deep repository include the construction of a prototype repository and a backfill experiment. This paper describes the status and the research plans of the Aspo HRL.
  • 佐藤 邦明, 五十嵐 敏文  地下水学会誌  36-  (3)  p329  -336  1994/08  [Not refereed][Not invited]
  • SHITAGAKI HISASHI, IGARASHI TOSHIFUMI  電力土木  (241)  100  -105  1992/09  [Not refereed][Not invited]
  • IGARASHI TOSHIFUMI  環境技術  18-  (4)  251  -254  1989/04  [Not refereed][Not invited]
  • 伊藤英司, 丹保憲仁, 五十嵐敏文  北海道公害防止研究所報  (10)  105  -112  1983/12  [Not refereed][Not invited]

Industrial Property Rights

  • 特許5314388:高アルカリ水処理装置    2013/07/12
    五十嵐敏文, 藤田光則  
    特願2008-288456

Awards & Honors

  • 2020/06 Hokkaido Industrial Safety and Inspection Department Distinguished service award for mine safety
     Distinguished service for long-term mine safety 
    受賞者: Toshifumi Igarashi
  • 2014/06 The Japanese Geotechnical Society Geo-environmental Award
     自然由来重金属等の対策に関するマニュアル整備およびその普及による公共事業におけるコスト縮減の実現 
    受賞者: 北海道環境保全技術協会技術委員長五十嵐;敏文
  • 2009/05 Journal of Groundwater Hydrology 学会功労賞
     
    受賞者: Toshifumi Igarashi

Research Grants & Projects

  • 岩盤掘削ずり対策のための吸着層工法の評価・設計法の構築
    日本学術振興会:科学研究費補助金
    Date (from‐to) : 2014/04 -2017/03 
    Author : 五十嵐 敏文
  • 岩盤掘削ずりに対する溶出試験および不溶化・吸着試験の標準化
    Japan society for the Promotion of Science:Grant-in-Aid for Scientific Research
    Date (from‐to) : 2011/04 -2014/03 
    Author : T. Igarashi
  • geochemical reaction between water and rock
    Date (from‐to) : 2001

Educational Activities

Teaching Experience

  • Advanced Groundwater Environment Engineering
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Hydrogeology
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
  • Advanced Groundwater Environment Engineering
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Advanced Groundwater Environment Engineering
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Inter-Graduate School Classes(Educational Program):PARE
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : エネルギー,バイオマス,水資源,地下水,通信ネットワーク,交通システム
  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 環境汚染、環境修復、環境毒性学、資源開発、環境経済
  • Inter-Graduate School Classes(Educational Program):JICA-University Alliance for Development Studies
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
  • Inter-Graduate School Classes(Educational Program):PARE
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 人口,人間活動,資源,環境,食料,作物,家畜,土地,土壌,河川,沿岸,海洋,水,地下水、地盤環境、水循環、大気,化石燃料,鉱物,農業,水産業,林業,工業,生態系,乱獲,貧困,飢餓,飽食,自給率,持続可能性,気候変動,侵食,遺伝,育種,種苗生産、化学物質,公害,リスクマネージメント,農薬,食品添加物,生物合理的病虫害防除,衛生昆虫制圧,ゼロエミッション,インターネット,無線ネットワーク,環境保護技術,低消費電力, インターンシップ
  • Hydrogeology
    開講年度 : 2018
    課程区分 : 博士後期課程
    開講学部 : 工学院
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Advanced Groundwater Environment Engineering
    開講年度 : 2018
    課程区分 : 博士後期課程
    開講学部 : 工学院
    キーワード : 地下空間, 地下水流動, 溶質移行, 土壌・地下水汚染とその浄化,環境影響評価
  • Environmental Chemistry
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 水循環 水質 天然水 溶解度 吸着 水質分析
  • Groundwater Hydrology
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 水循環 地下水流動 溶質移行 土壌・地下水汚染 浄化技術
  • Experiments for Sustainable Resources Engineering Ⅲ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 構造解析,物性評価,鉱物の利用,流体の分析,選別技術
  • Sustainable Resources Engineering Ⅰ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 地殻資源 資源探査 鉱山開発 採掘技術 未利用資源 都市鉱山 リサイクル 坑廃水処理 環境修復
  • Introduction to Mineral Resources Engineering
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 地殻資源 鉱床 開発技術 環境問題 未利用資源 リサイクル
  • Resources Chemistry Ⅱ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 反応工学,物質収支,速度論,反応モデル,生物反応

Campus Position History

  • 2016年4月1日 
    2017年3月31日 
    大学院工学院副学院長
  • 2016年4月1日 
    2017年3月31日 
    大学院工学研究院副研究院長
  • 2017年4月1日 
    2019年3月31日 
    教育研究評議会評議員
  • 2017年4月1日 
    2019年3月31日 
    大学院工学院副学院長
  • 2017年4月1日 
    2019年3月31日 
    大学院工学研究院副研究院長
  • 2019年4月1日 
    2021年3月31日 
    技術支援本部副本部長

Position History

  • 2016年4月1日 
    2017年3月31日 
    大学院工学院副学院長
  • 2016年4月1日 
    2017年3月31日 
    大学院工学研究院副研究院長
  • 2017年4月1日 
    2019年3月31日 
    教育研究評議会評議員
  • 2017年4月1日 
    2019年3月31日 
    大学院工学院副学院長
  • 2017年4月1日 
    2019年3月31日 
    大学院工学研究院副研究院長
  • 2019年4月1日 
    2021年3月31日 
    技術支援本部副本部長


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