• Economic and Environmental Geology
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• v.34 no.5
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• pp.485-498
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• 2001

This study was objected to identify the temporal and spatial variations oi groundwater quality and contamination using monthly groundwater monitoring data collected from 30 wells in Daejung watershed, Jeju Island. Water samples were analyzed for major cations. anions, and environmental isotopes including $^{18}0-H_2$O,$^{2}H-H_2$O and$^{15}$ N-NO$_3$The groundwater represented mostly Na(Mg)-HCO$_3$ type, with local change toward Ca-HCO$_3$ type and Na-Cl type. Groundwater quality depends upon various factors such as the local groundwater flowpaths, input of surface contaminants with recharge events, and sea-water intrusion along the coastal area. Nitrate contamination changed temporally according to recharge events and spatially. $\delta$$^{18}$ O-$\delta$$_2$H data for monthly sampled groundwaters showed distinctive clusters, implying that groundwater was originated from independent precipitation, and subsequently recharged very fash. Using$\delta$$^{15}$ N-NO$_3$ data, major sources of nitrate and its areas of influence could be identified. The areas under influence of livestock farms showed relatively high NO$_3$-N concentrations and$\delta$$^{15}$ N values higher than 5$\textperthousand$. The agricultural areas in southeastern part showed very high concentrations of NO$_3$-N with the $\delta$$^{15}$ N values of lower than 5$\textperthousand$.

• Water for future
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• v.16 no.4
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• pp.245-252
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• 1983

Recently river water pollution in Korea is given rise to serious problem in aspect of crop production, drinking well, water contamination and etc. Under these urgent situations, it is prime importance to protect water resources from pollutants. An environmental isotope survey of the groundwater form the shallow alluvial and the underlying crystalline rock aquifer of the Han River Basin has been undertaken, Analysis of the data has I) confirmed the hypothesis that the groundwater from the metropolitan area is recharged from the river whereas that form the non-urbanized region of the Basin is replenished by the infiltrating precipitation; ii) shown that crystalline rock aquifers are recharged by the ground water form the overlying alluvium. Old groundwater is a group of wells with tritium values in the range of 0 to 2 TU. These low values indicate that the water sampled was recharged much ealier, at least a few decades, than the other groundwater samples of higher tritium content. The low values in this region may, in fact, reflect the effect of the impermeable clay layers which impede infilteration from the surface. Stable isotope evidence confirmed that a recharge in the karst area occurs at a significantly greater elevation than that to the alluvial aquifer. An analysis of the tritium level collected over an annual cycle suggests that the residence time of groundwater is probably not more than a few months. There does not appear to be any correlation between the trace level of Zn, Mn and Pb in the groundwater and the mechanism of the recharge.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.497-500
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• 2007

지열류량은 지열자원 개발 시 지열 이상대를 찾는데 있어서 중요한 자료로 사용된다. 우리나라의 지체구조별 지열류량 평균은 경기육괴 66 $mW/m^2$, 옥천습곡대 65 $mW/m^2$, 영남육괴 60 $mW/m^2$, 경상분지 72 $mW/m^2$, 연일분지 75 $mW/m^2$이다. 이러한 대륙 내의 지표 지열류량은 상부 지각내의 방사성 동위원소 붕괴에 의한 열생산율(${\sim}40%$)과 하부지각 및 상부맨틀에서부터 전도되어 올라온 지열류량(${\sim}60%$)으로 설명할 수 있다. 따라서 지열류량의 결정에 있어서 열생산율의 정보는 중요한 부분을 차지한다. 열생산율은 지각 내에 존재하는 주요 방사성 동위 원소인 U, Th, K의 붕괴열에 의한 것이며, 열생산율의 측정은 gamma-ray log 자료를 이용하는 방법과 화학분석을 통한 방법이 있다. 이 연구에서는 두 가지 방법을 이용하여 총 123개(화강암 86개, 편마암 37개) 지점에서의 열생산율을 산출하였다. 화강암의 열생산율 평균은 2.15 ${\mu}W/m^3$이며, 편마암의 열생산율 평균은 2.22 ${\mu}W/m^3$로 나타났다. 지체구조별 열생산율의 평균은 경기육괴 2.52 ${\mu}W/m^3$, 옥천습곡대 2.16 ${\mu}W/m^3$, 영남육괴 2.35 ${\mu}W/m^3$, 경상분지 2.01 ${\mu}W/m^3$로 나타났다. 지체 구조별 열생산율과 지열류량의 상관성 분석에서 우리나라의 경우 지열류량이 높은 지역에서 열생산율이 낮은 경향을 보인다. 따라서 열생산율이 지표 지열류량을 결정하는데 있어서 가장 중요한 요소가 아님을 확인할 수 있다.

• Journal of the Korean Geographical Society
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• v.33 no.3
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• pp.377-394
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• 1998

The magnetic record of loess deposits may be one of the most detailed and useful records of Quatermary climate change on the continents. Stratigraphic variations of magnetic parameters define alternating zones of high and low concentrations of magnetic minerals. All the concentration-sensitive magnetic parameters show an increase within the interstadial Gilman Canyon Formation and interglacial Brady soil and a systematic decrease within the Wisconsinan Peoria loess. The influence of climate change on magnetic records is confirmed by a high correlation between the magnetic parameters and biological proxies. Rock magnetic data appear to be better correlated with temperature-sensitive biological proxies than does a precipitation-sensitive index such as the aridity index derived from opal phytoliths. Simultaneous, higher resolution sampling of magnetic and biological proxies proved to be a better sampling tactic, and enhanced the feasibility of rock magnetic parameters as independent climate proxies.

• 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.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.93-102
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• 2007

The runoff characteristics of organic matter in turbid water were investigated in eleven tributary streams of the Han River system, Korea. The flow-weighted event mean concentrations of organic matter ranged from 1.5 to 3.2 mg $L^{-1}$ of DOM and 2.2 of 29.1 mg $L^{-1}$ of POM, respectively. The SUVA value which reflects the proportion of humic substance in organic matters was higher during the rainfall season, meaning that the runoff of refractory form increase in this period. Stable carbon isotope ratios of both POM and DOM were different among streams, which reflect the sources of organic matter. DOM isotope ratios were less depleted of $^{13}C$ than that of POM by approximately 1 to $2%_{\circ}$ ${\delta}^{13}C$ of the several turbid streams (the Mandae Stream, the Jawoon Stream, and the Daegi stream) were heavier than those of clear streams. ${\delta}^{13}C$ values in the turbid upstream tributaries were similar to those of downstream reaches (such as the Soyang River, the Sum River, and the Seo River). From the ${\delta}^{13}C$ analysis of POM it could be calculated that $C_4$ pathway contributed approximately 15.9 to 23.6% of organic matter in several turbid upstream sites, and over 20% in the three sites of large downstream reaches. On the contrary it contributed only 9.1 to 12.8% in clear streams of forest watersheds. In the Soyang River, $C_4$ pathway organic matter contributed 8.8% of the DOM pool.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.351-367
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• 1995

The elemental geochemistry and oxygen isotopes of illite/smectite (I/S) have been studied in relationship to the mineralogical trend in the Reindeer D-27 well, Beaufort-Mackenzie Basin. The increase in concentrations of $K_2O$, Rb and rare earth elements (REE), the decrease in concentrations of tetrahedral elements such as Mg, Ti, Sc, Zn and Zr, and the increase in concentrations of tetrahedral elements such as Be and V can be related to I/S compositions that vary systematically with depth. Layer formulae of S- and I-layers are estimated as $[Al_{1.57}Fe_{.19}Mg_{.31}Ti_{.07}][Si_{3.84}Al_{.16}]O_{10}(OH)_2$ and $[Al_{1.84}Mg_{.16}][Si_{3.33}Al_{.67}]O_{10}(OH)_2$, respectively. The mobilization of REE appears to occur during illitization. The increase in concentrations of REE, especially La and Ce, with depth is probably linked to incorporation of ions with high valency (e.g. $V^{5+}$) in tetrahedral sites. The excess valency due to V is partly counter-balanced by ions with low valency (e.g. $Be^{2+}$) and, in turn, the local valency deficiency caused by $Be^{2+}$ could be compensated by high-charge interlayer cations such as REE (＋3). ${\delta}^{18}O$ values of I/S range from 2.91 to 15.72‰ (SMOW), and increase with depth, contrasting to trends observed in the Gulf Coast and elsewhere. The increase in ${\delta}^{18}O$ of I/S results from the rapid increase in ${\delta}^{18}O$ of pore water that overcomes the decrease in temperature-dependent fractionation values with increasing burial depth (${\delta}^{18}O_{pore\;water}>-d{\Delta}/_{I/S-water};\;d{\delta}^{18}O_{I/S}>0$). Calculated ${\delta}^{18}O$ values of pore water in equilibrium with I/S suggest that the original water was probably meteoric water. The stratification of pore water is postulated from the presence of an isotopically light interval, about 450m thick. The depth range of the isotopically light zone overlaps, but does not coincide with the interval of lowered I-content and $K_2O$ concentrations, suggesting that oxygens may have been exchanged independently of mineralogical and geochemical reactions.

• Journal of the Korean earth science society
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• v.23 no.6
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• pp.474-485
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• 2002

The object of this study is to investigate the contamination degree and the interpretation of sea water intrusion phenomena with hydrogeochemical and hydrogen-oxygen stable isotope of coastal aquifer in the Gogum area, Korea. The physical characteristics of groundwaters is the neutral pH condition and transitional Redox environments, and groundwater is affected by sea water & surface water. The chemical properties of groundwaters are showing an increase in contamination owing to the sea water intrusion, waste water from the surface and agricultural chemicals. In the case of chloride, 6 samples of the groundwater in the study area are in excess of the drinking water standard. The Piper diagram shows the contamination in GG-4 and 14 by sea water intrusion. GG-3, 7 and 13 dominate the Na-HCO$_{3}$ type water and regional (GG-14) is indicated to dominate the Na-Cl type water such as sea water. According to the Sl (saturation index), sea water is oversaturated with respect to calcite and dolomite, GG-3, 14 and 18 are approaching the saturation state. The hydrogen-oxygen stable isotope ratio of groundwaters originates in the meteoric water, and groundwaters of GG-1, 5 and 14 display high oxygen isotope value due to surface water trespass and sea water intrusion. The result of this study, GG-14 is contaminated by sea water intrusion, groundwaters expected GG-3, 7 and 13 is in progress to artificial pollution and sea water intrusion.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.229-248
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• 2024

This investigated the hydrogeochemical and isotopic characteristics of geothermal waters, groundwaters, and surface waters in Dongrae-gu, Busan, South Korea, in order to determine the origins of the salinity components in the geothermal waters, and their formation mechanisms and heat sources The geothermal waters are Na-Cl-type, distinct from surrounding groundwaters (Na-HCO₃^- and, Ca-HCO₃^- (SO₄, Cl)-type) and surface waters (Ca-HCO₃(SO₄, Cl)-type). This indicates the geothermal waters formed at depth as compared with the groundwaters. δ¹⁸O and δD values of the geothermal waters are relatively depleted as compared with the groundwaters, due to altitude effects and deep circulation of the geothermal waters. Helium and neon isotope ratios (³ He/⁴He and, ⁴He/²⁰Ne) of the geothermal waters plot on a single mixing line between mantle (³He = 3.76~4.01%) and crust (⁴He = 95.99~96.24 %), indirectly suggesting that the heat source is due to the decay of radioactive elements in rocks. The geothermal reservoir temperatures were calculated using the silica-enthalpy and Giggenbach models, yielding values of 82~130℃, and the depth of the geothermal reservoir is estimated to be 1.7~2.9 km below the surface. The correlation between Cl/Na and Cl/HCO₃ for the Dongrae geothermal waters requires the input of salty water. The supply of saline composition is interpreted due to the dissolution of residual paleo-seawater.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.3
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• pp.126-132
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• 1999

Tritium. a radioisotope of hydrogen, is a constituent of water molecules and, therefore. is a ideal water tracer in hydrology. The tritium level of the precipitation in Korea has been monitored at the Pohang station from 1961 to 1976 by IAEA and has been analyzed from 1987 to present by KAERI. The tritium contents of the precipitation were recorded up to about 1,940 TU owing to world-wide nuclear testing in 1963. The contents have decreased and in present are about 10 TU. of which values are similar to those in pre-thermonuclear period. These data can be usefully applied to hydrological studies such as interpretation of relationship between groundwater and surface water and dating of groundwater.