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Takai, Shizuka; Shimada, Taro; Takeda, Seiji; Koike, Katsuaki*
Journal of Contaminant Hydrology, 251, p.104097_1 - 104097_12, 2022/12
Times Cited Count：3 Percentile：23.69(Environmental Sciences)When assessing the risk from an underground environment that is contaminated by radioactive nuclides and hazardous chemicals and planning for remediation, the contaminant plume distribution and the associated uncertainty from measured data should be estimated accurately. While the release history of the contaminant plume may be unknown, the extent of the plume caused by a known source and the associated uncertainty can be calculated inversely from the concentration data using a geostatistical method that accounts for the temporal correlation of its release history and groundwater flow modeling. However, the preceding geostatistical approaches have three drawbacks: (1) no applications of the three-dimensional plume estimation in real situations, (2) no constraints for the estimation of the plume distribution, which can yield negative concentration and large uncertainties, and (3) few applications to actual cases with multiple contaminants. To address these problems, the non-negativity constraint using Gibbs sampling was incorporated into the geostatistical method with groundwater flow modeling for contaminant plume estimation. This method was then tested on groundwater contamination in the Gloucester landfill in Ontario, Canada. The method was applied to three water soluble organic contaminants: 1,4-dioxane, tetrahydrofuran, and diethyl ether. The effectiveness of the proposed method was verified by the general agreement of the calculated plume distributions of the three contaminants with concentration data from 66 points in 1982 (linear correlation coefficient of about 0.7). In particular, the reproduced large spill of organic contaminants of 1,4-dioxane in 1978 was more accurate than the result of preceding minimum relative entropy-based studies. The same peak also appeared in the tetrahydrofuran and diethyl ether distributions approximately within the range of the retardation factor derived from the fraction of organic carbon.
Soler, J. M.*; Landa, J.*; Havlov
, V.*; Tachi, Yukio; Ebina, Takanori*; Sardini, P.*; Siitari-Kauppi, M.*; Eikenberg, J.*; Martin, A. J.*
Journal of Contaminant Hydrology, 179, p.89 - 101, 2015/08
Times Cited Count：42 Percentile：81.67(Environmental Sciences)Matrix diffusion is a key process for radionuclide retention in crystalline rocks. An in-situ diffusion experiment in granite matrix was performed at the Grimsel Test Site (Switzerland). Several tracers (HTO, Na
, Cs) were circulated through a borehole and the decrease in tracer concentrations was monitored for 2.5 years. Then, the borehole section was overcored and the tracer profiles in the rock were analyzed. Transport distances in the rock were 20 cm for HTO, 10 cm for Na and 1 cm for Cs. The dataset was analyzed with diffusion-sorption models by different teams using different codes, with the goal of obtaining effective diffusivities (De) and rock capacity factors. There was a rather good agreement between the values from different teams, implied that De and capacity factors in the borehole damaged zone are larger than those in the bulk rock. However, HTO seems to display large discrepancies between measured and modeled results.
, Na, I
and HTO in granodiorite; Laboratory-scale results and their extrapolation to the in situ conditionTachi, Yukio; Ebina, Takanori*; Takeda, Chizuko*; Saito, Toshihiko*; Takahashi, Hiroaki*; Ouchi, Yuji*; Martin, A. J.*
Journal of Contaminant Hydrology, 179, p.10 - 24, 2015/08
Times Cited Count：33 Percentile：74.14(Environmental Sciences)Matrix diffusion and sorption are important processes in the assessment of radionuclide transport in crystalline rocks. Diffusion and sorption parameters for Cs, Na, I and HTO were determined by through-diffusion and batch sorption experiments using granodiorite samples from the Grimsel Test Site, Switzerland. The De values were in the order Cs, Na, HTO, I. The capacity factor and Kd values show the same trends. The dual depth profiles for Cs and Na can be interpreted by a near-surface Kd increment. The microscopic analysis indicated that this is caused by high porosity and sorption capacities in disturbed biotite minerals on the sample surface. The Kd values derived from the dual profiles are likely to correspond to Kd dependence on the grain sizes of crushed samples in the batch experiments. The results of the in situ LTD experiments were interpreted reasonably well by using transport parameters derived from laboratory data and extrapolating them to in situ conditions.
Ijiri, Yuji*; Saegusa, Hiromitsu; Sawada, Atsushi; Ono, Makoto*; Watanabe, Kunio*; Karasaki, Kenji*; Doughty, C.*; Shimo, Michito*; Fumimura, Kenichi*
Journal of Contaminant Hydrology, 103(3-4), p.168 - 181, 2009/01
Times Cited Count：9 Percentile：28.95(Environmental Sciences)Qualitative evaluation of the effects of uncertainties originating from scenario development, conceptual models, and parameter values is an important subject in the area of safety assessment for high-level nuclear waste disposal. In this study, regional-scale groundwater flow analyses for the Tono area, Japan were conducted using three continuous models which were designed to handle heterogeneous porous media. We evaluated the simulation results to quantitatively analyze uncertainties originating from conceptual models. We found that uncertainties originating from conceptual models (1) greatly depend on boundary conditions and hydrological structures to be modeled, which are assigned by modelers, and (2) are larger than uncertainties originating from the variance in realizations of the Monte Carlo method in stochastic modeling.
Uchida, Masahiro
Journal of Contaminant Hydrology, 69(1-2), p.1 - 26, 2004/00
Times Cited Count：22 Percentile：48.21(Environmental Sciences)None
Sato, Haruo
Journal of Contaminant Hydrology, 0 Pages, 2003/00
The thermodynamic properties (activity, relative partial molar Gibbs free energy, enthalpy and entropy) of porewater in sandstone were obtained as a function of water content and temperature by vapor pressure measurements.
; Alexander, W. R.*; Frieg, B.*; Schild M*
Journal of Contaminant Hydrology, 61, p.131 - 145, 2002/00
Times Cited Count：25 Percentile：49.97(Environmental Sciences)None
Tachi, Yukio; Shibutani, Tomoki; Sato, Haruo; Yui, Mikazu
Journal of Contaminant Hydrology, 47(2-4), p.171 - 186, 2001/02
Times Cited Count：37 Percentile：66.60(Environmental Sciences)None
Kozai, Naofumi; Inada, Koichi*; Kozaki, Tamotsu*; Sato, Seichi*; Ohashi, Hiroshi*; Bamba, Tsunetaka
Journal of Contaminant Hydrology, 47(2-4), p.149 - 158, 2001/02
Times Cited Count：15 Percentile：41.14(Environmental Sciences)no abstracts in English
; W.R.Alexan*; W.Kickmaie*; Frieg, B.*; McKinl, I. G.*
Journal of Contaminant Hydrology, 47, p.335 - 348, 2001/00
Times Cited Count：25 Percentile：55.33(Environmental Sciences)None
; W.R.Alexan*; H.Dollinge*; Ch.Buhler*; P.Haag*
Journal of Contaminant Hydrology, 35, p.115 - 130, 1999/00
Times Cited Count：29 Percentile：62.12(Environmental Sciences)None
; Shibutani, Tomoki; Sato, Haruo;
Journal of Contaminant Hydrology, 35, p.77 - 89, 1998/00
Times Cited Count：37 Percentile：69.72(Environmental Sciences)None
Yamaguchi, Tetsuji;
Journal of Contaminant Hydrology, 35, p.55 - 65, 1998/00
Times Cited Count：29 Percentile：62.12(Environmental Sciences)no abstracts in English
Matsunaga, Takeshi; Ueno, Takashi; Amano, Hikaru; Y.Tkatchenko*; A.Kovalyov*; Watanabe, Miki*; Onuma, Yoshikazu*
Journal of Contaminant Hydrology, 35, p.101 - 113, 1998/00
Times Cited Count：45 Percentile：75.10(Environmental Sciences)no abstracts in English
; Onuki, Toshihiko; Isobe, Hiroshi; Yanase, Nobuyuki; Sekine, Keiichi; ;
Journal of Contaminant Hydrology, 35, p.191 - 199, 1998/00
Times Cited Count：4 Percentile：18.50(Environmental Sciences)no abstracts in English
Kumata, Masahiro; Vandergraaf, T. T.*
Journal of Contaminant Hydrology, 35(1-3), p.31 - 40, 1998/00
Times Cited Count：6 Percentile：23.69(Environmental Sciences)no abstracts in English
Yamaguchi, Tetsuji; Sakamoto, Yoshiaki; ; T.T.Vandergraaf*
Journal of Contaminant Hydrology, 26, p.109 - 117, 1997/00
Times Cited Count：30 Percentile：65.66(Environmental Sciences)no abstracts in English
