AGE04-01

会場:301A

時間:5 月 24 日 10:00-10:15

有機ヒ素化合物の土壌中における吸着挙動
Adsorption behavior of organoarsenic compounds in soils
田中 雅人 1∗ ; 高橋 嘉夫 1
TANAKA, Masato1∗ ; TAKAHASHI, Yoshio1
1
1

東京大学
The University of Tokyo

The arsenic pollution is a world problem. Natural originated inorganic arsenic compounds are predominant cause of thewater-related disease. In addition, anthropogenic originated organoarsenic compounds such as phenylarsonic acid (PAA) anddiphenylarsinic acid (DPAA) are also pollution source. For example, DPAA polluted well water caused serious health problems in
Kamisu, Japan. These phenyl arsenic compounds are considered as a decomposition product of chemical warfare agents produced
during World Wars I and II, and even now such compounds still remain in the ground. Recently, adsorption and mobility of thesearomatic arsenic compounds in agricultural soils have been investigated. However, their adsorption mechanisms on soil are still
unknown. In general, the adsorption property of chemical compounds influences its migration process in natural environments
such as soil-water system. Thus, it is important to understand the adsorption mechanism of the arsenic compounds to predict
future fate of them in environment. Recently, we reported adsorption structures of PAA and DPAA on ferrihydrite obtainedby X-ray absorption fine structure (XAFS) analysis and quantum chemical calculations [1]. In this study, we conducted As Kedge XAFS measurements for organoarsenic compounds adsorbed on soil, as well as adsorption experiments, to understand theiradsorption behavior in soils. The results of EXAFS analysis suggest that all arsenic compounds in this study adsorbed on Fe or Al(oxyhydr)oxide in the soil mainly regardless of the organic functional groups. This fact indicates that the Fe/Al-(oxyhydr)oxides
can control the mobility of organorasenic compounds in the ground.
References:[1] Tanaka M, Togo Y S, Yamaguchi N and Takahashi Y 2014 J Colloid Interface Sci., 415, 13.
キーワード: 吸着挙動, 有機ヒ素, X 線吸収微細構造, 土壌
Keywords: adsorption behavior, organoarsenic, XAFS, soil

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AGE04-02

会場:301A

時間:5 月 24 日 10:15-10:30

Impact of Injecting Heated Water into Aquifer on Groundwater Quality
Impact of Injecting Heated Water into Aquifer on Groundwater Quality
山田 孝大 1∗ ; Dang Quoc Thyuet3 ; 坂口 巌 2 ; 斎藤 広隆 3
YAMADA, Koudai1∗ ; DANG QUOC, Thyuet3 ; SAKAGUCHI, Iwao2 ; SAITO, Hirotaka3
1

東京農工大学大学院農学府, 2 埼玉大学大学院理工学研究科, 3 東京農工大学大学院農学研究院
Graduate school of Ecoregion Science, Tokyo University of Agriculture and Technology, 2 Graduate School of Science andEngineering, Saitama University, 3 Department of Ecoregion Science, Tokyo University of Agriculture and Technology

1

In late years, usage of geothermal heat energy, one of the renewable energy sources, draws attention in Japan. The geothermalheat can be used through heat pumps for building heating and cooling. A heat pump can extract heat energy either from the groundusing underground heat exchangers or from pumped groundwater. While the former is referred to as a closed-type ground source
heat pump (GSHP), the latter is known as an open-type ground source heat pump. The open-type GSHP systems also require
either recharging heated or cooled groundwater into aquifers or discharging it into surface water systems. There are various
advantages of using the open-type GSHP systems; energy efficiency is much higher than the closed-type GSHP systems. On theother hand, altering groundwater temperature may cause environmental impact such as elution of toxic elements from the aquiferor changes in microbial activities in the aquifer. However, such environmental impact caused by the open-type GSHP systems has
been rarely studied and is generally poorly understood. To maintain its sustainable usage, more data on environmental impacts
need to be collected from field experiments. The main objective of this study is, therefore, to investigate the impact of injecting
heated water into the aquifer on groundwater temperature and its quality.
A field experiment was conducted from October 7 to December 2 in Fuchu campus of Tokyo University of Agriculture andTechnology in 2014. Groundwater pumped from a pumping well was heated to 30 oC before it was injected to a confined aquifer
at GL-50m from an injection well installed 10-m away from the pumping well at a rate of 20 L/min. The temperature of theground below GL-10m is almost constant at 17 oC year-round at the experimental site. The heating load was therefore equivalent
to 18.1 kW. Changes in temperature and element concentrations in groundwater were observed at two 50-m long observation
wells installed at 1.4-m (O-1) and 5.3-m (O-5) away from the injection well. Temperature sensors were installed every 5 m at
O-1 and O-5. Groundwater samples were collected from two aquifers; one at GL-40m (shallow) and another one at GL-50m(deep), from O-1 and O-5, every two or three days during the experiment. EC, pH, DO, ORP, and turbidity were measured
immediately after samples were collected, while concentrations of sixteen trace elements and major ions were measured later
using ICP-MS and IC, respectively.
Temperatures of the deep aquifer at O-1 and O-5 rose from 17 oC to 23 oC and 22 oC, respectively, while those of otherdepths remained almost unchanged or increased slightly, indicating that heated water was indeed directly injected to the deep
aquifer. While pH, EC, and DO did not changed, ORP showed a gradual decreasing trend in both aquifers. Turbidity waslargely affected by injecting heated water as it increased to 60 NTU at the deep aquifer at O-1. That of the other aquifers stayed
almost unchanged before, during, and after injecting heated water. As concentrations of elements might be affected not only bychanges in temperature, but also by physical injection, it may be required to separate the impact of different processes. One of
the approaches to do that is to take concentration ratios with an inert tracer. This is known as an internal standard method. As
there was no artificial tracer added in this experiment, zinc, one of the more stable elements, was used as a tracer. Ratios to Zn
concentration increased significantly during heating for some elements, such as Al.
From the field experiment, it was clearly shown that the turbidity of groundwater was strongly affected. As for trace elements
and major ions, while it was shown that injecting heated water might increase concentrations or concentration ratios for someelements, more careful data analysis needs to be done to clarify the mechanism of such effects.

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AGE04-03

会場:301A

時間:5 月 24 日 10:30-10:45

粒径および熱物性が多孔質体中の熱分散現象に与える影響
Effects of particle size and thermal properties on thermal dispersion characteristics inporous media
万代 俊之 1∗ ; 濱本 昌一郎 1 ; 井本 博美 1 ; 西村 拓 1 ; 小松 登志子 2
BANDAI, Toshiyuki1∗ ; HAMAMOTO, Shoichiro1 ; IMOTO, Hiromi1 ; NISHIMURA, Taku1 ; KOMATSU, Toshiko2
1

東京大学大学院農学生命科学研究科, 2 埼玉大学大学院理工学研究科
Graduate School of Agricultural and Life Sciences, the University of Tokyo, 2 Graduate School of Science and Engineering,
Saitama University
1

Understanding heat transport process in saturated porous media is essential, in regard to a widespread use of ground source
heat pump systems and design of geologic repositories for high-level nuclear wastes. However, knowledge of thermal dispersion
occurred due to advective heat flow is limited in the mechanisms of heat transport process. In this study, one-dimensional heatand solute transport experiments were conducted using glass beads with different size fractions, and stainless steel sphere withhigh thermal conductivity. Effects of particle size, thermal properties, and flow velocities on thermal dispersion characteristics
and the difference between thermal and solute dispersion characteristics were discussed based on the column experiments. Glassbeads with smaller size fraction showed smaller increase in thermal dispersion coefficient at higher flow velocity as compared tothe one with larger size fraction. Flow velocity dependency on thermal dispersion coefficient was insignificant for stainless steel
sphere, indicating thermal conduction dependent heat transport is dominant in the column due to higher thermal conductivity ofthe stainless steel.
キーワード: 熱分散, 溶質分散, 熱物性
Keywords: thermal dispersion, solute dispersion, thermal properties

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AGE04-04

会場:301A

時間:5 月 24 日 11:00-11:15

荒川低地堆積物の重金属の溶出と存在形態に温度環境が与える影響
Effects of temperature environment in dissolution and chemical forms of heavy metals of
sediment in Arakawa lowland
植木 崇 1 ; 斎藤 健志 1∗ ; 濱本 昌一郎 2 ; 川本 健 1 ; 小松 登志子 1
UEKI, Takashi1 ; SAITO, Takeshi1∗ ; HAMAMOTO, Shoichiro2 ; KAWAMOTO, Ken1 ; KOMATSU, Toshiko1
1

埼玉大学大学院理工学研究科, 2 東京大学大学院農学生命科学研究科
Graduate School of Science and Engineering, Saitama University, Saitama, JAPAN, 2 Graduate School of Agricultural and Life
Sciences, The University of Tokyo, Tokyo, JAPAN1

Global warming, heat island phenomenon in urban areas, and increased use of geothermal energy would affect the subsurface thermal, chemical, and biological environment. Change in subsurface temperature might affect dissolution and transport ofchemical materials and the subsurface microbial activities. However, effects of temperature change on the subsurface environment including dissolution and chemical forms of heavy metals have not been fully clarified. In this study, effects of temperature
on dissolution and chemical forms of heavy metals in sediment of Arakawa Lowland, Kanto district, Japan have been investigatedby laboratory experiments.
Laboratory experiments to evaluate the relation between temperature and dissolution characteristics were conducted under
three different temperature conditions (15o C, 25o C and 40o C). Five chemical forms of heavy metals in residues from the dissolution experiment were also fractioned (Water soluble, Exchangeable, Bound to carbonates, Bound to iron and manganese oxides
and Bound to organic matter) by the sequential extraction method. These experiments were conducted on sediment samples
obtained from boring cores at around 17m, 31m, 39m and 44m depth (denoted as 17m-sample, 31m-sample, 39m-sample and44m-sample, respectively).
Results showed that temperature conditions affected dissolution characteristics and chemical forms of heavy metals. Especially, boron in 17m-sample (marine sediment) and arsenic in 31m-sample (non-marine sediment) dissolved more at higher
temperature and linear relations between temperature and dissolved concentration of these components were observed. Additionally, temperature condition also affected their chemical forms. Under 40o C and 25o C conditions, Bound to iron and manganeseoxides and Exchangeable forms of boron in 17m-sample both decreased and Water-soluble boron increased compared to the 15o C
condition. Also under 40o C and 25o C conditions, Bound to iron and manganese oxides form of arsenic in 31m-sample decreased
and Water-soluble and Exchangeable arsenic both increased compared to the 15o C. These results imply that hardly-soluble formsof boron and arsenic might change to readily-soluble forms at higher temperature.
キーワード: 地表面温度, 溶出特性, 存在形態, 沖積堆積物
Keywords: subsurface temperature, dissolution characteristics, chemical forms, alluvial sediment

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AGE04-05

会場:301A

時間:5 月 24 日 11:15-11:30

LOCALLY AVAILABLE SOILS AS LINER MATERIALS FOR DEVELOPING COUNTRIES: A COMPARISON WITH GEOSYNTHETIC CLAY LINERLOCALLY AVAILABLE SOILS AS LINER MATERIALS FOR DEVELOPING COUNTRIES: A COMPARISON WITH GEOSYNTHETIC CLAY LINERRASHID, Hafiz muhammad awais1∗ ; SAITO, Takeshi1 ; KURUKULASURIYA, L. chandana2 ;PRIYANKARA, Nadeej H.3 ; KEN, Kawamoto4
RASHID, Hafiz muhammad awais1∗ ; SAITO, Takeshi1 ; KURUKULASURIYA, L. chandana2 ;PRIYANKARA, Nadeej H.3 ; KEN, Kawamoto4
1

Graduate School of Science and Engineering, Saitama University, Japan, 2 Department of Civil Engineering, Faculty of Engineering, University of Peradeniya, Sri Lanka, 3 Department of Civil and Environmental Engineering, University of Ruhuna,
Galle, Sri Lanka, 4 Grad. Sch. of Sci. & Engg., International Institute for Resilient Society, Saitama University, Japan1
Graduate School of Science and Engineering, Saitama University, Japan, 2 Department of Civil Engineering, Faculty of Engineering, University of Peradeniya, Sri Lanka, 3 Department of Civil and Environmental Engineering, University of Ruhuna,
Galle, Sri Lanka, 4 Grad. Sch. of Sci. & Engg., International Institute for Resilient Society, Saitama University, Japan

Solid waste management has become a major issue for the urban areas of developing countries. Due to rapid increase inurbanization coupled with the rise in community living standards the generation of municipal solid waste is highly accelerated
in past few decades. At present most of the landfill practice in developing countries is open dumping without proper measures tomitigate the migration of contaminants to surrounding environment. It is the need of hour to construct engineering landfills withimpermeable liners to avoid groundwater and surface water pollution. Most of the engineered landfills in developed countries areequipped with commercially available liner material known as Geosynthetic Clay Liner (GCL). GCLs are popular due to theirextremely low hydraulic conductivity which is primarily due to the presence of a thin layer of bentonite. However, due to economic constraints, developing countries cannot afford engineered landfills equipped with such commercially available liners. In
contrast, Locally Available Clayey Soils (LACs) are less expensive and can be used as bottom liners under the provision that theymeet the recommended criteria for base liner. A detailed comparison between GCL and LAC with respect to both geotechnicaland hydraulic performance can therefore provide the basis for using appropriate LACs as landfill liner material.
This study employed locally available soils obtained from Moragahakanda area of Srilanka(hereafter referred to as Soil M).
Swell index, plasticity index and Hydraulic conductivity tests were carried out on Soil M and its mixtures with bentonite component of GCL. Soil-bentonite mixtures were prepared by mixing Soil M with 5 % and 10 % bentonite. Experimental Investigations
were carried out using de-aerated water and 1M CaCl2 as hydrating liquids. The hydraulic conductivity tests were carried out on
non consolidated and pre-consolidated samples to investigate the effect of consolidation on hydraulic conductivity of candidate
soils. Data on pure bentonite was used to examine the performance of Soil M and mixture soils compared to GCL. Results
showed that the nature of hydrating liquid has an insignificant effect on swell Index and plasticity index of the candidate soils
when compared to pure bentonite. Hydraulic conductivity was found to decrease with an increase in bentonite content whenpermeated with de-aerated water. However, the effect was found insignificant for CaCl2 permeation. An increase in consolidation pressure caused a decrease in hydraulic conductivity irrespective of permeating liquid and bentonite content. At very
high consolidation pressure, all the candidate soils were found to exhibit much lower values of hydraulic conductivities than the
maximum recommended value for base liners.

キーワード: Locally Available Soils, Geosynthetic Clay Liners, Soil-Bentonite Mixtures, Plasticity Index, Swell Index, Hydraulic Conductivity
Keywords: Locally Available Soils, Geosynthetic Clay Liners, Soil-Bentonite Mixtures, Plasticity Index, Swell Index, Hydraulic
Conductivity

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AGE04-06

会場:301A

時間:5 月 24 日 11:30-11:45

Significant Improvement to Imaging Hydraulic Heterogeneity in Heterogeneous Geologic
Media via Hydraulic Tomography
Significant Improvement to Imaging Hydraulic Heterogeneity in Heterogeneous Geologic
Media via Hydraulic Tomography
ILLMAN, Walter1∗
ILLMAN, Walter1∗
1
1

University of Waterloo
University of Waterloo

Hydraulic parameters such as hydraulic conductivity (K) and specific storage (Ss) of geologic media are heterogeneous at multiple scales. A large number of techniques have been developed to deal with this heterogeneity, but little information is available
on its performance in predicting groundwater flow and solute transport. In this presentation, I review the various heterogeneity
mapping methods and introduce the concept of Hydraulic Tomography (HT). HT is a new approach to map the heterogeneity ofthe subsurface. It is analogous to geophysical tomography but different in a sense that the method relies on multiple pumping
tests as sources of signals. These signals or drawdowns are detected in neighboring monitoring intervals. With a suitable inverse
model, one can then estimate the three-dimensional spatial variability in K and Ss. One significant advantage of the approachis that it provides direct information on connectivity in hydraulic parameters, which is very important in contaminant transport
problems. Research over the last decade has shown that this is a very robust technique and the estimated parameters are morereliable in predicting independently conducted pumping tests and tracer tests. I will introduce various synthetic, laboratory andfield experimental results, compare HT against other heterogeneity mapping methods, and discuss future research directions.

キーワード: heterogeneity, contaminant transport, fractured rocks, stochastic hydrology, subsurface characterization, connectivity
Keywords: heterogeneity, contaminant transport, fractured rocks, stochastic hydrology, subsurface characterization, connectivity

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AGE04-07

会場:301A

時間:5 月 24 日 11:45-12:00

Interactive effects of EC and pH on nitrous oxide emissions and denitrification
Interactive effects of EC and pH on nitrous oxide emissions and denitrification
HA, Thi kim thanh1∗ ; MAEDA, Morihiro1
HA, Thi kim thanh1∗ ; MAEDA, Morihiro1
1
1

Graduate School of Environmental and Life Science, Okayama University
Graduate School of Environmental and Life Science, Okayama University

Long-term fertilizer applications and saline water irrigation lead to the accumulation of salts and changes in soil pH. Thesechanges may in turn affect N2 O emissions from soil. Interactive effects of EC and pH on N2 O emissions were studied by using
paddy soil in Ushimado, Okayama Prefecture, Japan. Closed incubation experiments were conducted in 100-mL glass bottles for
72 h at 25o C. Each bottle contained 5 g of air-dried soil and 25 mL of solution, which includes KNO3 (10 mg NO3 -N L−1 ) and
NaCl (0 M , 0.005 M , 0.01 M , 0.05 M , 0.1 M , 0.2 M ) for adjusting different electric conductivity (EC) levels under different pH:acid (HCl 0.005 M ), neutral (no adjustment), and alkaline (NaHCO3 0.005 M ). Nitrous oxide concentration in the headspaceof the bottle was measured 3 h, 24 h, 48 h, and 72 h after incubation with gas chromatograph (GC-8A, Shimadzu, Kyoto,
Japan). After gas collection, the solution was taken out for measuring pH, EC and concentrations of NH4 + and NO3 − . Results
indicated that pH was a significant factor controlling N2 O emissions (P <0.05). Nitrous oxide emissions were greater in higher
EC treatments under the acid treatment. Nitrous oxide emissions peaked at 24 h of incubation and fell sharply afterwards due tofurther dentrification process. At 24 h, the highest N2 O emissions was measured in 0.2 M NaCl (7.5 mg kg soil−1 ), followed byin 0.1 M , 0.05 M , 0.01 M , 0.005 M and 0 M treatments, which were 6.7, 5.1, 3.8, 2.0, and 1.2 mg N kg soil−1 , respectively.
Nitrous oxide reductase was sensitive to both high EC and low pH condition. In neutral and alkaline treatments, there was no
significant effect of EC on N2 O emissions during 72 h incubation (P >0.05). The N2 O emissions were 0 mg kg soil−1 at 3 hafter incubation then ranged from 0.02 to 0.11 mg N kg soil−1 . Ammonium concentration increased over the incubation periods.
Higher EC promote NH4 + release. There was no significant difference in NO3 − removal among treatments at different EC levels(P >0.05). We conclude that low pH increased N2 O emissions and higher EC under acid conditions promoted N2 O emissions.
キーワード: Denitrification, EC, nitrous oxide, paddy soil, pH
Keywords: Denitrification, EC, nitrous oxide, paddy soil, pH

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AGE04-08

会場:301A

時間:5 月 24 日 12:00-12:15

Spatial prediction of soil water retention curves from particle size distribution data using
Arya-Paris model
Spatial prediction of soil water retention curves from particle size distribution data using
Arya-Paris model
志賀 渉 1∗ ; 向後 雄二 2 ; 斎藤 広隆 2
SHIGA, Wataru1∗ ; KOHGO, Yuji2 ; SAITO, Hirotaka2
1

東京農工大学農学府, 2 東京農工大学大学院農学研究員
Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 2 Department of Ecoregion Science, Tokyo
University of Agriculture and Technology
1Predicting soil water retention curves (SWRC) or their model parameters at any unsampled locations using a geostatisticalspatial interpolation technique requires a number of high quality retention data. Obtaining SWRC is, however, generally tedious,time consuming, and sometime expensive. Therefore, pedotransfer functions (PTF), which allow one to predict soil hydraulicproperties, such as SWRC, from easily measured soil properties, have been developed. One of the common PTF by Aryaand Paris (AP) predicts water retention curves from particle size distributions (PSD) and dry bulk densities. In this study ageostatistical spatial interpolation technique was coupled with the AP model to predict water retention curves at given unsampled
locations from PSD. There are two approaches available: (1) First, SWRC are predicted from PSD at given observed locations
using the AP model. SWRC are then predicted at given unsampled locations through the geostatistical spatial interpolation
technique from those predicted by the AP model. This approach is referred to as the PTF-first and Interpolation-later approach or
the PI approach. (2) First, PSD and the bulk densities are predicted at given unsampled locations using the geostatistical spatial
interpolation technique from observed PSD. Then, SWRC are predicted at the unsampled locations by the AP model from theinterpolated PSD and bulk densities. This approach is then referred to as the Interpolation-first and PTF-later approach or the IP
approach. Current study compares the performance of these two approaches to predict SWRC at any given unsampled location.
Ordinary kriging (OK) one of the most commonly used geostatistical interpolation technique was used. The data used in thisstudy were obtained from the Las Cruces trench site database, which contains water retention data for 448 soil samples. The
dataset was then split into two sets, prediction and validation sets. This allows for the computation of prediction errors (meanabsolute error or MAE and mean error or ME). The results show that performances of the PI and IP approaches were comparable,
while the PI generally requires less workload as the number of kriging one needs to perform is much less for the PI compared to
the IP. It was also shown that MAE were almost the same between the PI and the IP.

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