• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.148-154
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• 1998

Gubong gold-mine, previously one of the largest gold mines in Korea, is located at the mid-west of the South Korea. In the areas nearby the mine, the shallow groundwater was the major source for domestic and farming water-supply. Soil contamination by Cd, Cu, Pb and Zn was previously known in this area. This study is objected to identify quality of the shallow groundwater, possibly affected by the mine tailings. Samples were collected from a nearby stream, shallow groundwater and seepage from the tailings. Chemical analysis for the water quality includes major cations such as Na, K, Ca, and Mg, anions as F, Cl, NO$_3$, SO$_4$, HCO$_3$, and trace elements as Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd, Pb, Se, As, Hg. Water types could be drawn into four groups from the plots of Piper, Stiff diagrams and cluster analysis. SAR-Conductivity plot indicates the water does not pose either alkalinity or salinity hazards for irrigation. Major contaminant in groundwater appeared to be arsenic, released from arsenopyrites in tailings by oxidation. Dredging of buried railing materials could stimulate the release of arsenic from the sediments to the groundwater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.128-131
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• 2001

We evaluated natural attenuation of petroleum hydrocarbons in a shallow aquifer using a modeling study. The studied shallow aquifer was severely contaminated with petroleum hydrocarbons, especially toluene, ethylbenzene and xylenes (i.e, TEX). The exact spill history was not known. Therefor we used a contaminant level in May 1999 (the first sampling date of our integrated study) as an initial contaminant concentration. we calibrated required transport parameters using the contamination levels obtained from groundwater analyses in September of 1999. For fate and transport of the petroleum contaminants, five case 2 with sorption and degradation. case 3 with sorption and degradation (half decay constant compared with case 2), case 4 with degradation but no sorption, and case 5 with sorption but no degradation. For sorption and degradation, a linear sorption isotherm and first order irreversible decay was assumed, respectively and no additional contamination source to groundwater is also assumed.

• Water for future
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• v.52 no.8
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• pp.28-33
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• 2019

This study is presented to estimate groundwater recharge in Sukhuma District of Southern Laos. The groundwater recharge is estimated by using the water table fluctuation method from observation groundwater levels at eleven domestic wells and five paired observation wells (shallow and deep). The results show that a value of specific yield for the shallow fractured sandstone aquifer in the Sukhuma District is quantified at approximately 0.03, Groundwater recharge for 2012-13 and 2015-16 is estimated at 5% (118 mm) and 4% (95 mm) of annual rainfall. respectively. The results of the current study provide useful basic information for future groundwater resource management planning in Sukhuma District. The methods applied in this study may be also useful for studying the groundwater recharge in regions with limited field data.

• Journal of Soil and Groundwater Environment
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• v.23 no.1
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• pp.30-40
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• 2018

To evaluate potential impacts of shallow groundwater by the leachate from buried carcass, we investigated hydrochemical characteristics of both leachate and shallow groundwater from monitoring wells and surrounding shallow groundwater wells in an area potentially affected by pig carcass burial. The hydrochemical survey was conducted before and after the relocation of a burial pit. The leachate samples and the groundwater affected by leachate showed the hydrochemistry of $Ca-HCO_3$ type with high $NH_4{^+}$ concentrations, while unaffected groundwater was mostly the $Ca(Na)-Cl+NO_3$ type due to pervasive impacts from agrochemicals. The results of factor analysis on hydrochemical data showed the followings: 1) contamination of groundwater from agro-livestock farming and livestock burial are coexisting in the study area, 2) among ionic species, $HCO_3{^-}$, $NH_4{^+}$, $NO_3{^-}$ and Mn are very useful to differentiate the groundwater contamination from leachate, and 3) groundwater contamination by leachate has been recognized around the monitoring wells even after the relocation of a burial pit, likely due to residual contaminants in surrounding soils. Therefore, it is suggested that continued monitoring of groundwater contamination should be conducted after the relocation of carcass burial pits.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.1
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• pp.32-46
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• 2000

Hydrogeochemical and isotope ($\delta$$^{18}$ O, $\delta$D, $^3$H, $\delta$$^{13}$ C, $\delta$$^{34}$ S, $^{87}$ Sr/$^{86}$ Sr) studies of various kinds of waters (thermal groundwater, deep groundwater, shallow groundwater, and surface water) from the Yusung area were carried out in order to elucidate their geochemical characteristics such as distribution and behaviour of major/minor elements, geochemical evolution, reservoir temperature, and water-rock interaction of the thermal groundwater. Thermal groundwater of the Yusung area is formed by heating at depth during deep circlulation of groundwater and is evolved into Na-HCO$_3$type water by hydrolysis of silicate minerals with calcite precipitation and mixing of shallow groundwater. High NO$_3$contents of many thermal and deep groundwater samples indicate that the thermal or deep groundwaters were mixed with contaminated shallow groundwater and/or surface water. $\delta$$^{18}$ O and $\delta$D are plotted around the global meteoric water line and there are no differences between the various types of water. Tritium contents of shallow groundwater, deep groundwater and thermal groundwater are quite different, but show that the thermal groundwater was mixed with surface water and/or shallow groundwater during uprising to surface after being heated at depths. $\delta$$^{13}$ C values of all water samples are very low (average -16.3$\textperthousand$%o). Such low $\delta$$^{13}$ C values indicate that the source of carbon is organic material and all waters from the Yusung area were affected by $CO_2$ gas originated from near surface environment. $\delta$$^{34}$ S values show mixing properties of thermal groundwater and shallow groundwater. Based on $^{87}$ Sr/$^{86}$ Sr values, Ca is thought to be originated from the dissolution of plagioclase. Reservoir temperature at depth is estimated to be 100~1$25^{\circ}C$ by calculation of equilibrium method of multiphase system. Therefore, the thermal groundwaters from the Yusung area were formed by heating at depths and evolved by water-rock interaction and mixing with shallow groundwater.

• The Journal of Engineering Geology
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• v.14 no.4 s.41
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• pp.469-485
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• 2004

The purpose of this study is to investigate the hydrochemical characteristics of groundwater in the Umsung area, and to elucidate the effect of host rock type, well depth and mineralization zone on the groundwater chemistry. The geology of the study area consists of Jurassic granite and Cretaceous sedimentary rocks, which are bounded by a fault. Most of shallow groundwaters exploited in the Jurassic granite area are used for agricultural purpose, whereas the deep groundwaters in the Cretaceous sedimentary rocks are used for a drinking water. The shallow groundwater shows weak acidic pH, the electrical conductivity ranging from $142\;to\;903\;{\mu}S/cm$, and the chemical type of $Ca-HCO_3\;to\;Ca-Cl(SO_4,\;NO_3)$. A few of shallow groundwaters are contaminated by nitrate, and show high concentration of Fe, Mn and Zn, that reflects the effect of a mineralization zone. The deep groundwater shows neutral to weak alkaline pH, higher electrical conductivity than that of shallow groundwater, and the chemical type of $Ca-HCO_3$. The seepage water from the abandoned mines does not have the characteristics such as acidic pH, high concentration of heavy metals and high sulfate content. The hydrogen and oxygen isotopes of groundwater indicates an altitude effect of the recharge area between deep groundwater and shallow groundwater. In conclusion, the chemical composition of groundwater complicately reflects the effects of their host rocks, well depth, agricultural activity and mineralization zone in the study area.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.86-97
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• 2007

The principal component analysis was performed to identify the general characteristics of groundwater level changes from 202 deep and 112 shallow wells monitoring data, respectively, which came from the National Groundwater Monitoring Stations operated by KWATER with time spans of 156 continuous weeks from 2003 to 2005. Eight principal components, which accounted for 80% of the variability of the original time series, were extracted for water levels of shallow and deep monitoring wells. As a result of cluster analysis using the loading value of three principal components for shallow wells, shallow monitoring wells were divided into 3 groups which were characterized with a response time to rainfall (Group 1: 4.6 days, Group 2: 24.1 days, Group 3: 1.4 days), average long-term trend of water level (Group 1: $2.05{\times}10^{-4}$ m/day, Group 2: $-7.85{\times}10^{-4}$ m/day, Group 3: $-3.51{\times}10^{-5}$ m/day) and water level difference (Group 1 < Group 2 < Group 3). Additionally, they showed significant differences according to a distance to the nearest stream from well (Group 3 < Group 2 < Group 1), topographic slope of well site (Group 3: plain region, Group 1: mountainous region) and groundwater recharge rate (Group 3 < Group 2 < Group 1) with a p-value of 0.05.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.122-126
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• 2005

Groundwater monitoring wells (about 70 wells) were extensively installed in 28 sites surrounding Lake Texoma, located on the border of Oklahoma and Texas, to assess the impact of geochemical stressors to shallow groundwater quality. The monitoring wells were classified into three groups (residential area, agricultural area, and oil field area) depending on their land uses. During a two-year period from 1999 to 2001 the monitoring wells were sampled every three months on a seasonal basis. Water quality assay consisted of 25 parameters including field parameters, nutrients, major ions, and trace elements. Occurrence and level of inorganics in groundwater samples were related to the land-use and temporal change.

• Economic and Environmental Geology
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• v.42 no.6
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• pp.541-548
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• 2009

The Dongrae thermal water area located at the southeastern marginal part of the Korean Peninsula is one of the oldest hot springs in Korea. The Dongrae thermal water shows Na-Cl type of water chemistry, whereas the shallow cold groundwater is Ca(-Na)-$HCO_3$ type. In this paper, we discuss the age of the Dongrae hot spring, i.e. groundwater cycle among meteoric water-surface water-shallow groundwater-hot spring water. The $^{87}Sr/^{86}Sr$ ratios of the thermal water in Dongrae area range from 0.705663 to 0.705688 and are lower than those of groundwater, surface water and rain water as well as aquifer bearing granite. These Sr isotopic signatures in the Dongrae thermal water indicate that the circulation rate between thermal water and current meteoric water including groundwater, surface water and rain water in the Dongrae area should be very slow. The $^{14}C$ age of the Dongrae hot spring water range from $1,271{\pm}36$ BP(before present) to $2,467{\pm}36$ BP whereas that of the shallow groundwater is $-495{\pm}33$ BP. This suggests that the period of groundwater cycle among meteoric water, surface water, shallow groundwater and hot spring should be more than 1,270 years. Then, it also indicates that the present Dongrae hot spring may be a mixed water between the old thermal water heated for at least 1,270 years and the present shallow cold groundwater.

• Journal of Soil and Groundwater Environment
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• v.18 no.2
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• pp.36-44
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• 2013

The objectives of this study were to identify the characteristics of shallow groundwater from the oil-contaminated site for a long period and to evaluate the applicability of biopile technology to treat the soil excavated from it. The eight monitoring wells were installed in the contaminated site and pH, Electrical Conductivity (EC), Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), Temperature and the concentrations of major ions and pollutants were measured. The VOCs in soil gas were monitored during biopile operation and TPH concentration was analyzed at the termination of the experiment. The pH was 6.62 considered subacid and EC was 886.19 ${\mu}S/cm$. DO was measured to be 2.06 mg/L showing the similar characteristic of deep groundwater. ORP was 119.02 mV indicating oxidation state. The temperature of groundwater was measured to be $16.97^{\circ}C$. The piper diagram showed that groundwater was classified as Ca-$HCO_3$ type considered deep groundwater. The ground water concentration for TPH, Benzene, Toluene, Xylene of the first round was slightly higher than that of the second round. The concentration of carbon dioxide of soil gas was increased to 1.3% and the concentration of VOCs was completely eliminated after the 40 days. The TPH concentration showed 98% remediation efficiency after the 90 days biopile operation.