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Author Kim, Y.; Lee, K.-S.; Koh, D.-C.; Lee, D.-H.; Lee, S.-G.; Park, W.-B.; Koh, G.-W.; Woo, N.-C.
Title Hydrogeochemical and isotopic evidence of groundwater salinization in a coastal aquifer: a case study in Jeju volcanic island, Korea Type Journal Article
Year 2003 Publication Journal of Hydrology Abbreviated Journal
Volume 270 Issue 3 Pages 282-294
Keywords Jeju volcanic island, Coastal aquifer, Groundwater salinization, Hydrogeochemistry, Environmental isotopes, Mixing process
Abstract In order to identify the origin of saline groundwater in the eastern part of Jeju volcanic island, Korea, a hydrogeochemical and isotopic study has been carried out for 18 observation wells located in east and southeast coastal regions. The total dissolved solid contents of groundwaters are highly variable (77–21,782mg/l). Oxygen, hydrogen, sulfur, and strontium isotopic data clearly show that the saline water results from mixing of groundwater with seawater. Strontium isotopic compositions and Br/Cl and I/Cl ratios strongly suggest that the source of salinity is modern seawater intrusion. Hydrogeochemical characteristics based on bivariate diagrams of major and minor ions show that changes in the chemical composition of groundwater are mainly controlled by the salinization process followed by cation-exchange reactions. The highly permeable aquifers at the east coastal region are characterized by low hydraulic gradient and discharge rate and high hydraulic conductivity as compared with other regions. These properties enhance the salinization of groundwater observed in the study area. Based on the Cl, Br, and δ18O data, seawater was determined to have intruded inland some 2.5km from the coastline. Considering the poor correlation of sampling depth and Cl concentrations observed, the position of seawater-freshwater interface is not uniformly distributed in the study area, due to heterogeneities of the basaltic aquifers.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN (down) 0022-1694 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Kim2003282 Serial 172
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Author Han, D.M.; Song, X.F.; Currell, M.J.; Yang, J.L.; Xiao, G.Q.
Title Chemical and isotopic constraints on evolution of groundwater salinization in the coastal plain aquifer of Laizhou Bay, China Type Journal Article
Year 2014 Publication Journal of Hydrology Abbreviated Journal
Volume 508 Issue Pages 12-27
Keywords Laizhou Bay, Coastal aquifers, Groundwater hydrochemistry, Stable isotopes, Saltwater intrusion
Abstract Summary A hydrochemical-isotopic investigation of the Laizhou Bay Quaternary aquifer in north China provides new insights into the hydrodynamic and geochemical relationships between freshwater, seawater and brine at different depths in coastal sediments. Saltwater intrusion mainly occurs due to two cones of depression caused by concentrated exploitation of fresh groundwater in the south, and brine water for salt production in the north. Groundwater is characterized by hydrochemical zonation of water types (ranging from Ca–HCO3 to Na–Cl) from south to north, controlled by migration and mixing of saline water bodies with the regional groundwater. The strong adherence of the majority of ion/Cl ratios to mixing lines between freshwater and saline water end-members (brine or seawater) indicates the importance of mixing under natural and/or anthropogenic influences. Examination of the groundwater stable isotope δ18O and δ2H values (between −9.5‰ and −3.0‰ and −75‰ and −40‰, respectively) and chloride contents (∼2 to 1000meq/L) of the groundwater indicate that the saline end-member is brine rather than seawater, and most groundwater samples plot on mixing trajectories between fresh groundwater (δ18O of between −6.0‰ and −9.0‰; Cl<5meq/L) and sampled brines (δ18O of approximately −3.0‰ and Cl>1000meq/L). Locally elevated Na/Cl ratios likely result from ion exchange in areas of long-term freshening. The brines, with radiocarbon activities of ∼30 to 60 pMC likely formed during the Holocene as a result of the sequence of transgression-regression and evaporation; while deep, fresh groundwater with depleted stable isotopic values (δ18O=−9.7‰ and δ2H=−71‰) and low radiocarbon activity (<20 pMC) was probably recharged during a cooler period in the late Pleistocene, as is common throughout northern China. An increase in the salinity and tritium concentration in some shallow groundwater sampled in the 1990s and re-sampled here indicates that intensive brine extraction has locally resulted in rapid mixing of young, fresh groundwater and saline brine. The δ18O and δ2H values of brines (∼−3.0‰ and −35‰) are much lower than that of modern seawater, which could be explained by 1) mixing of original (δ18O enriched) brine that was more saline than presently observed, with fresh groundwater recharged by precipitation and/or 2) dilution of the palaeo-seawater with continental runoff prior to and/or during brine formation. The first mechanism is supported by relatively high Br/Cl molar ratios (1.7×10−3–2.5×10−3) in brine water compared with ∼1.5×10−3 in seawater, which could indicate that the brines originally reached halite saturation and were subsequently diluted with fresher groundwater over the long-term. Decreasing 14C activities with increasing sampling depth and increasing proximity to the coastline indicate that the south coastal aquifer in Laizhou Bay is dominated by regional lateral flow, on millennial timescales.
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ISSN (down) 0022-1694 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Han201412 Serial 174
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Author Nadler, A.; Magaritz, M.; Mazor, E.
Title Chemical reactions of sea water with rocks and freshwater: Experimental and field observations on brackish waters in Israel Type Journal Article
Year 1980 Publication Geochimica et Cosmochimica Acta Abbreviated Journal
Volume 44 Issue 6 Pages 879-886
Keywords
Abstract Four major processes are observed to take place in the coastal aquifer of Israel, detectable even in the short times of water contact with the carbonate-containing host rocks. Three are chemical reactions, Ca2+-Mg2+ exchange, Na+-Ca2+ or Na+-Mg2+ base exchange, SO2−4 reduction and the fourth is dilution by freshwater. These reactions and their effects on the chemical composition of the waters were demonstrated experimentally. The range of chemical changes observed in the laboratory experiments overlap the range of the studied natural waters. This indicates that simulation of geologically long-term rock-water interaction could be achieved in laboratory experiments even at low temperatures.
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ISSN (down) 0016-7037 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Nadler1980 Serial 33
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Author Wigley, T.M.L.; Plummer, L.N.
Title Mixing of carbonate waters Type Journal Article
Year 1976 Publication Geochimica et Cosmochimica Acta Abbreviated Journal
Volume 40 Issue 9 Pages 989-995
Keywords
Abstract When mineral solutions of different compositions are mixed, the molalities and activities of individual ions in the mixture are often non-linear functions of their end-member values. This non-linearity is particularly significant in determining mineral saturation levels. Mixtures of saturated solutions may be either undersaturated or supersaturated depending on the end-member compositions and the physical conditions in which end-members and their mixtures exist. In carbonate solutions important non-linear effects occur due to redistribution of carbonate species. In extreme cases this causes mixture pH to be below both the end-member pH values. A simple but precise computer program (WATMIX) has been developed for calculating mixture composition for closed and open system mixing of arbitrary end-members. A number of mixing examples are considered which allow one to isolate three important processes leading to non-linear behaviour: the algebraic effect, the δPCO2 effect, and the ionic strength effect.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN (down) 0016-7037 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Wigley1976 Serial 40
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Author Rina, K.; Datta, P.S.; Singh, C.K.; Mukherjee, S.
Title Isotopes and ion chemistry to identify salinization of coastal aquifers of Sabarmati River Basin Type Journal Article
Year 2013 Publication Abbreviated Journal Current Science
Volume 104 Issue 3 Pages 335-344
Keywords
Abstract The lower reaches of the Sabarmati River Basin in Gujarat have intense agricultural and industrial activities and this part is affected by problems of groundwater salinity. Here we attempt to assess the processes governing the causes of groundwater salinity in the coastal alluvial aquifer, employing δ18O and δD isotopes in integration with ionic ratio. The different hydrochemical facies such Na–Mg–HCO3–Cl, Na–Cl–SO4, Na–Mg–Cl–HCO3–SO4 and Na–Cl of groundwater show the occurrence of complex geochemical phenomenon in the study area. Ionic ratio (such as Mg2+/Ca2+, Na+/Cl−, SO24/Cl-, K+/Cl−) and isotopic composition (δ18O and δD) of groundwater indicate that while in coastal areas seawater intrusion is taking place, in inland areas various anthropogenic activities and overexploitation have induced salinity in groundwater. Over-pumping of groundwater has also induced lateral intermixing of highly saline water in the vicinity of coastal areas with relatively fresh/low saline groundwater along specific flow pathways.
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Corporate Author Thesis
Publisher Current Science Association Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN (down) 0011-3891 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Serial 190
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