Journal of Groundwater Hydrology

Changes in water quality of Masugatanoike spring over 28 years (19 7 5-2002)

Kouji TSUSHIMA, Kenji NAKANE, Kyoko TSUCHIHASHI, Yoko TAKEUCHI, Mari S ...

2008 Volume 50 Issue 1 Pages 3-16
Published: February 29, 2008
Released on J-STAGE: December 11, 2012

DOIhttps://doi.org/10.5917/jagh1987.50.3

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Changes in water quality of Masugatanoik e spring over 28 years (1975-2002) and the factors affecting them were examined. Although the changes were not always stable, the increasing trend in water temperature and decreasing trend in the concentrations of nitrate and chloride ions and volatile organochlorine compounds were observed after 1990. The high concentrations of nitrate ion (-500μmol/L) suggested the influence of sub-soil infiltration of domestic wastewater. However, th is concentration did not decrease dramatically even after the completion of sewerage system in the recharge area. The responses of spring water quality were very slow and had a significant time lag. This study showed the importance of long-term monitoring of spring water quality.

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Estimation of NAPL content in saturated sandy soil using dual-probe heat-pulse method

Toshitsugu MOROIZUMI, Wakako HANZAWA, Choichi SASAKI

2008 Volume 50 Issue 1 Pages 17-24
Published: February 29, 2008
Released on J-STAGE: December 11, 2012

DOIhttps://doi.org/10.5917/jagh1987.50.17

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The simple methods for estimating NAPL content in saturated sandy soil using a volumetric heat capacity have been proposed as a fundamental study for measuring the NAPL content in groundwater. A dual-probe heat-pulse method was used to measure the volumetric heat capacity. The estimations of NAPL contents which were obtained by substituting the measurements of volumetric heat capacity into its model did not have a better accuracy than those by the calibration equation between known NAPL content and volumetric heat capacity, but could be close to the known NAPL contents. The estimations of NAPL contents were greatly improved when the regression line between the measured and estimated volumetric heat capacities.

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Chemical interaction between arsenic and iron with changing redox condition *

Yoshinari HIROSHIRO, Keita ODA, Md. Abdul HALIM, Abdur RAZZAK, Kenji J ...

2008 Volume 50 Issue 1 Pages 25-32
Published: February 29, 2008
Released on J-STAGE: December 11, 2012

DOIhttps://doi.org/10.5917/jagh1987.50.25

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Arsenic in soil is strongly adsorbed by F e-sediment existing as ferric hydroxide(Fe(III)) under oxidative condition. The present study focuses on chemical interactions between As and Fe in water at different experimental conditions. In this report, column experiments were carried out to observe the behavior among As, Fe and Mn at different redox conditions. Consequently, when it came to reduced condition in soil, ferric hydroxide began to dissolve, and simultaneously As concentration increased in the effluent of the soil column. On the other hand, the behavior between Mn and As was not recognized to be correlated. The concentrations of As and Fe in the effluent decreased when this reduced effluent passed through the oxidation column filled with glass beads.

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Visit to valuable water springs (80) Valuable water springs in Miyako-island

Hiroki TAKAMURA, Tadashi KONO

2008 Volume 50 Issue 1 Pages 33-42
Published: February 29, 2008
Released on J-STAGE: December 11, 2012

DOIhttps://doi.org/10.5917/jagh1987.50.33

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