Hydrogen In Groundwater Research Articles

Seasonality in groundwater recharge in Coastal Southwestern India and its hydrological implications based on stable isotopes (δ18O, δD)

This study observes and interprets the spatio-temporal variation in the oxygen and hydrogen isotopic composition (δ18O, δD) of shallow groundwater in the Southwestern Coastal state of India, Kerala, in terms of seasonally varying rainfall, physiography, and hydrogeological settings of this region. This study identifies effective groundwater recharge sources and their relative contributions and provides first-order estimates of submarine groundwater discharge by interpreting the spatio-temporal variations in the stable isotopes of oxygen and hydrogen in groundwater, collected from 225 locations for pre-monsoon and post-monsoon seasons in conjunction with the isotopic composition of rainfall. Spatio-temporal variations in the δ18O and d-excess, with other hydrogeological data, reveals that: (1) ∼4.9 Billion Cubic Meter (BCM) of fresh water from rainfall during May to October mixes with ∼5.9 BCM of residual pre-monsoon groundwater across Kerala. (2) ∼ 11% area of Kerala is additionally recharged by the NE monsoon rainfall. (3) The annual groundwater recharge varies physiographically from ∼2.2 BCM in the lowland to ∼1.5 BCM in the midland and ∼1.2 BCM in highland regions. (4) On an annual basis, 41% of replenishable groundwater is drained as SGD into the Arabian Sea.

Features of the distribution of molecular hydrogen in groundwater in various geological and tectonic conditions of Uzbekistan

As a result of generalization and analysis of previously performed work on the determination of hydrogen on the day surface, a picture of the distribution of hydrogen concentration in the aeration zone was obtained. The increased concentration of hydrogen on the day surface and in the aeration, zone is associated with the most favourable conditions for the transit of fluids from the folded Palaeozoic basement to the surface cover (upper part of the Earth’s crust). These zones are zones of active fluid conductivity, which leads to a high concentration of hydrogen on the day surface. Intense linear anomalies are confined to the zone of intersection of the Tuzkoy-Rometan transverse fault with the Bukhara-Gissar regional fault, with which seismic events are associated (epicentres Gazli earthquakes occurred 08.04.1976, 17.05.1976 and 19.03.1984). Analysis of long-term observations of gas composition on an example of molecular hydrogen in groundwater southwestern part Karzhantaus fault, covering the territory of Tashkent city and its surroundings, obtained hydrogen concentration distribution pattern area. A different concentration of hydrogen in the fault zone was revealed, associated with the heterogeneity of the geological and structural structure.

Identifying the origin and geochemical evolution of groundwater using hydrochemistry and stable isotopes in the Subei Lake basin, Ordos energy base, Northwestern China

Abstract. A series of changes in groundwater systems caused by groundwater exploitation in energy base have been of great concern to hydrogeologists. The research aims to identify the origin and geochemical evolution of groundwater in the Subei Lake basin under the influence of human activities. Water samples were collected, and major ions and stable isotopes (δ18O, δD) were analyzed. In terms of hydrogeological conditions and the analytical results of hydrochemical data, groundwater can be classified into three types: the Quaternary groundwater, the shallow Cretaceous groundwater and the deep Cretaceous groundwater. Piper diagram and correlation analysis were used to reveal the hydrochemical characteristics of water resources. The dominant water type of the lake water was Cl-Na type, which was in accordance with hydrochemical characteristics of inland salt lakes; the predominant hydrochemical types for groundwater were HCO3–Ca, HCO3–Na and mixed HCO3–Ca–Na–Mg types. The groundwater chemistry is mainly controlled by dissolution/precipitation of anhydrite, gypsum, halite and calcite. The dedolomitization and cation exchange are also important factors. Rock weathering is confirmed to play a leading role in the mechanisms responsible for the chemical composition of groundwater. The stable isotopic values of oxygen and hydrogen in groundwater are close to the local meteoric water line, indicating that groundwater is of modern local meteoric origin. Unlike significant differences in isotopic values between shallow groundwater and deep groundwater in the Habor Lake basin, shallow Cretaceous groundwater and deep Cretaceous groundwater have similar isotopic characteristics in the Subei Lake basin. Due to the evaporation effect and dry climatic conditions, heavy isotopes are more enriched in lake water than in groundwater. The low slope of the regression line of δ18O and δD in lake water could be ascribed to a combination of mixing and evaporation under conditions of low humidity. Comparison of the regression line for δ18O and δD showed that lake water in the Subei Lake basin contains more heavily isotopic composition than that in the Habor Lake basin, indicating that lake water in the discharge area has undergone stronger evaporation than lake water in the recharge area. Hydrochemical and isotopic information of utmost importance has been provided to decision makers by the present study so that a sustainable groundwater management strategy can be designed for the Ordos energy base.

The isotope altitude effect reflected in groundwater: a case study from Slovenia

This paper presents the stable isotope data of oxygen (δ18O) and hydrogen (δ2H) in groundwater from 83 sampling locations in Slovenia and their interpretation. The isotopic composition of water was monitored over 3 years (2009–2011), and each location was sampled twice. New findings on the isotopic composition of sampled groundwater are presented, and the data are also compared to past studies regarding the isotopic composition of precipitation, surface water, and groundwater in Slovenia. This study comprises: (1) the general characteristics of the isotopic composition of oxygen and hydrogen in groundwater in Slovenia, (2) the spatial distribution of oxygen isotope composition (δ18O) and d-excess in groundwater, (3) the groundwater isotope altitude effect, (4) the correlation between groundwater d-excess and the recharge area altitude of the sampling location, (5) the relation between hydrogen and oxygen isotopes in groundwater in comparison to the global precipitation isotope data, (6) the groundwater isotope effect of distance from the sea, and (7) the estimated relation between the mean temperature of recharge area and δ18O in groundwater.

Isotopic variations of oxygen and hydrogen in groundwater of carbonate aquifer in an arid environment

The stable isotopic characteristics were used together with the total chloride to assess changes in groundwater from recharge zones into the carbonate aquifer in an arid environment. The aquifer under study represents a major source of groundwater and thermal springs in Al-Ain city, which are located at the northern part of Jabal Hafit in the United Arab Emirates (UAE). The relationship between oxygen and hydrogen isotopic composition of groundwater is established and is described by δD = 2.2δ18O − 9.96. The lower slope and y-intercept of groundwater samples relative to the local meteoric waterline suggests that the isotopic enrichment is due to the evaporation of shallow groundwater after recharge occurs. The majority of the shallow groundwater samples have a negative deuterium excess (d-excess) which might be ascribed to high a degree of evaporation, while most of the groundwater samples from deep wells, have a positive value of d-excess which may be related to a low degree of evaporation. The δ18O values of the thermal waters suggest enrichment towards δ18O of the carbonate rocks because of the exchange with oxygen at higher temperatures. A possible mixing between thermal or hot water and shallow groundwater is evident in some samples as reflected by δD vs. Cl and d-excess vs. δ18O plots.

Stable isotopic and geochemical characteristics of groundwater in Kherlen River basin, a semi-arid region in eastern Mongolia

Summary Inorganic solute ion concentrations and stable isotopes of oxygen and hydrogen in groundwater, river water and precipitation were investigated to gain insight into the groundwater recharge process in the Kherlen River basin, a semi-arid region in eastern Mongolia. The solute constituents in the river water (main stream) were of Ca–HCO3 type, spatially invariant and low in concentration. Groundwater in the upstream region was also characterized by a Ca–HCO3 type, though all ion concentrations were higher than in the river water. On the other hand, the chemical composition of the groundwater in the midstream region (southern and eastern) was spatially variable and the Na+, Mg2+, Cl− and HCO 3 - concentrations were considerably higher than in the river water and upstream groundwater. The stable isotopic compositions showed an evaporation effect on the groundwater and river water, as well as an altitude effect in the precipitation and river water. Preferential recharge by relatively large rainfall events is thought to have caused the depleted isotopic ratio in the groundwater in the dry regions. The stable isotope, chemical and hydrological data suggest that the main stream water of the Kherlen River is recharged by precipitation that falls in a headwater region at an altitude of more than 1650 m, and that the interaction between the groundwater and river water is not dominant in the midstream and downstream regions of the river basin.

Study of stable isotopes in the Kouris catchment (Cyprus) for the description of the regional groundwater flow

The stable isotopes of oxygen and hydrogen in groundwater and precipitation were integrated for the description of groundwater flow in the Kouris catchment (Cyprus). The catchment consists of an ophiolitic complex in the North and sediments in the South. It is characterized by strong heterogeneity of the underground media and steep slopes of the topography. The regression line, constructed from the data of 70 rainfall samples, is described by the equation: δD=6.6 δ 18O+10.9, which shows evaporation during precipitation. The altitude gradients in the precipitation were estimated to be −1.7‰/100 m for δD and —0.27/100 m for δ 18O. The stable isotope analysis of 234 groundwater samples reflected fractionation due to evaporation. The origin of groundwaters in the catchment was described based on the regression equation between surface elevations and δD contents for 33 selected springs of the ophiolitic complex. It was found that the groundwaters in the ophiolitic aquifer and in the consolidated sediments originated from local recharge at high and low altitudes, respectively. On the contrary, the groundwater in the alluvium aquifer originates from the high altitudes in the ophiolitic complex. Additionally, δD data were used for the calibration of the recharge rates for a steady state groundwater flow and transport model. The resulting calibrated total steady state recharge rate was 100–130 mm per year.

Optimization of the Sampling Technique for the Determination of Dissolved Hydrogen in Groundwater

AbstractIn this study a field‐sampling technique for dissolved hydrogen (H2) in groundwater will be presented which allows the transport of gaseous samples into the laboratory for further analysis. The method consists of transferring the headspace trapped in a gas‐sampling bulb which is continuously purged by groundwater into previously evacuated vials using a gas‐tight syringe. Three transfer steps with preceding evacuation of the vial led to a H2‐recovery of 100 % in laboratory experiments. The method has been applied to determine H2 concentrations in an aquifer contaminated with chlorinated solvents.Tests concerning the effect of different pumping techniques on H2 concentrations revealed that most reliable values were obtained with a bladder pump, while an electrically driven submersible pump generated considerable amounts of hydrogen due to electrochemical interactions with the sampled water. Concentrations of dissolved hydrogen in field and laboratory samples were about two orders of magnitude higher when sampling was performed with the electrically driven submersible pump compared to sampling with the bladder pump and a peristaltic pump.Lab experiments with a Plexiglas reservoir to produce H2‐enriched water were used to study the effect of two tubing materials (PVC, polyamide) on H2 losses. PVC tubing turned out to allow transfer of H2‐enriched water over 25 m without significant losses, while PA‐tubing was not suitable for sampling of H2.