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Author Sarker, M.M.R.; Van Camp, M.; Islam, M.; Ahmed, N.; Walraevens, K. url  doi
openurl 
  Title Hydrochemistry in coastal aquifer of southwest Bangladesh : origin of salinity Type Journal Article
  Year 2018 Publication Environmental Earth Sciences Abbreviated Journal  
  Volume 77 Issue 2 Pages 20  
  Keywords Hydrochemistry,Stable isotope,Seawater intrusion,Coastal aquifer,Bangladesh,DAR-ES-SALAAM,SEAWATER INTRUSION,DELTA PLAIN,GROUNDWATER,DRINKING,TANZANIA,DROUGHT,COMPLEX  
  Abstract (down) In the coastal region of Bangladesh, groundwater is mainly used for domestic and agricultural purposes, but salinization of many groundwater resources limits its suitability for human consumption and practical application. This paper reports the results of a study that has mapped the salinity distribution in different aquifer layers up to a depth of 300 m in a region bordering the Bay of Bengal based on the main hydrochemistry and has investigated the origin of the salinity using Cl/Br ratios of the samples. The subsurface consists of a sequence of deltaic sediments with an alternation of more sandy and clayey sections in which several aquifer layers can be recognized. The main hydrochemistry shows different main water types in the different aquifers, indicating varying stages of freshening or salinization processes. The most freshwater, soft NaHCO3-type water with Cl concentrations mostly below 100 mg/l, is found in the deepest aquifer at 200-300 m below ground level (b.g.l.), in which the fresh/saltwater interface is pushed far to the south. Salinity is a main problem in the shallow aquifer systems, where Cl concentrations rise to nearly 8000 mg/l and the groundwater is mostly brackish NaCl water. Investigation of the Cl/Br ratios has shown that the source of the salinity in the deep aquifer is mixing with old connate seawater and that the saline waters in the more shallow aquifers do not originate from old connate water or direct seawater intrusion, but are derived from the dissolution of evaporite salts. These must have been formed in a tidal flat under influence of a strong seasonal precipitation pattern. Long dry seasons with high evaporation rates have evaporated seawater from inundated gullies and depressions, leading to salt precipitation, while subsequent heavy monsoon rains have dissolved the formed salts, and the solution has infiltrated in the subsoil, recharging groundwater.  
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  ISSN 1866-6280 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Sarker2018 Serial 194  
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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. url  openurl
  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 (down) 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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  ISSN 0022-1694 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Kim2003282 Serial 172  
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Author Bahir, M.; Ouhamdouch, S.; Carreira, P.M. url  doi
openurl 
  Title Geochemical and isotopic approach to decrypt the groundwater salinization origin of coastal aquifers from semi-arid areas (Essaouira basin, Western Morocco) Type Journal Article
  Year 2018 Publication Environmental Earth Sciences Abbreviated Journal  
  Volume 77 Issue 13 Pages 485  
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  Abstract (down) In arid and semi-arid areas, the groundwater is the main source of water supply and agricultural activity. Overexploitation of coastal aquifers and pollution vulnerability are among the main problems related to groundwater resources assessment and management in these zones. In fact, in the last decades, these resources have been threatened by a degradation of their quality and quantity that furthers natural and anthropic effects, such as climate change, seawater intrusion and overexploitation. However, the protection and management of these resources requires knowledge of the origin of their mineralization. In this study, the Essaouira basin is selected as a typical example. Stable isotopes (18O and 2H) together with geochemical data were used to identify the groundwater salinization origin in the coastal aquifers of the Essaouira basin. The results of both the approaches show that the groundwater mineralization is due to: (1) the dissolution of salt minerals, (2) the ion exchange phenomena, (3) seawater intrusion, and (4) sulphate reduction. Also, the recharge is supported by fast infiltration of oceanic precipitation without significant evaporation.  
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  ISSN 1866-6299 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Bahir2018 Serial 177  
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Author Carreira, P. M.; Marques, J. M. url  openurl
  Title Groundwater Salinity and Environmental Change Over the Last 20,000 Years: Isotopic Evidences in the Lower Sado Aquifer Recharge, Portugal Type Book Whole
  Year 2018 Publication Abbreviated Journal  
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  Abstract (down) Impacts of the Water Resources Variability on Cereal Yields in the Region of Souss-Massa Southern MoroccoErstes  
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  Publisher Springer Place of Publication Editor  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Serial 183  
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Author Han, D.; Currell, M.J. url  doi
openurl 
  Title Delineating multiple salinization processes in a coastal plain aquifer, northern China: hydrochemical and isotopic evidence Type Journal Article
  Year 2018 Publication Hydrology and Earth System Sciences Abbreviated Journal  
  Volume 22 Issue 6 Pages 3473-3491  
  Keywords Isotopes, China, multiple salinization  
  Abstract (down) Groundwater is an important water resource for agricultural irrigation and urban and industrial utilization in the coastal regions of northern China. In the past 5 decades, coastal groundwater salinization in the Yang–Dai river plain has become increasingly serious under the influence of anthropogenic activities and climatic change. It is pivotal for the scientific management of coastal water resources to accurately understand groundwater salinization processes and their causative factors. Hydrochemical (major ion and trace element) and stable isotopic (δ18O and δ2H) analysis of different water bodies (surface water, groundwater, geothermal water and seawater) were conducted to improve understanding of groundwater salinization processes in the plain's Quaternary aquifer. Saltwater intrusion due to intensive groundwater pumping is a major process, either by vertical infiltration along riverbeds which convey saline surface water inland, and/or direct subsurface lateral inflow. Trends in salinity with depth indicate that the former may be more important than previously assumed. The proportion of seawater in groundwater is estimated to have reached up to 13 % in shallow groundwater of a local well field. End-member mixing calculations also indicate that the geothermal water with high total dissolved solids (up to 10.6 g L−1) with depleted stable isotope compositions and elevated strontium concentrations (> 10 mg L−1) also mixes locally with water in the overlying Quaternary aquifers. This is particularly evident in samples with elevated Sr ∕ Cl ratios (> 0.005 mass ratio). Deterioration of groundwater quality by salinization is also clearly exacerbated by anthropogenic pollution. Nitrate contamination via intrusion of heavily polluted marine water is evident locally (e.g., in the Zaoyuan well field); however, more widespread nitrate contamination due to other local sources such as fertilizers and/or domestic wastewater is evident on the basis of NO3 ∕ Cl ratios. This study provides an example of how multiple geochemical indicators can delineate different salinization processes and guide future water management practices in a densely populated water-stressed coastal region.  
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  Call Number THL @ christoph.kuells @ hess-22-3473-2018 Serial 81  
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