Showing papers on "Environmental isotopes published in 2022"

Defining the Bounds of Using Radioactive Isotope Tracers to Sense Past Groundwater Recharge Under Transient State Conditions

Abstract: Analyzing groundwater systems in transient state is essential for understanding the response of groundwater recharge to changing environments. Radioactive isotopes have long been used to track recharge behavior, typically under steady state conditions. This study tests the limitations of using radioactive isotopes in confined aquifers and under transient conditions to sense changes in groundwater recharge rates over time. Four system parameters determine the bounds of this approach: the isotope half-life, the Péclet number (Pe), and mobile-immobile zone interactions. This study revealed that in confined groundwater systems where Pe ≥ 10, isotopes reflect transience when the half-life matches the water travel time down the flow path or the time elapsed from the change in velocity. This response is evident regardless of mobile-immobile interaction, suggesting that appropriate isotope selection is key to establishing past recharge regardless of aquifer lithology or geometry.

Investigation of the Origin of Hueco Bolson and Mesilla Basin Aquifers (US and Mexico) with Isotopic Data Analysis

Abstract: An important tool to identify the origin of a groundwater resource is the use of isotopic signatures. Isotopic signatures give us the age of water and provide information as to the water’s origin, potential transit at geologic structures, source of salinization, and possible recharge points. The purpose of this study was to collect and analyze well samples to evaluate isotopic tracers (δ18O and tritium) in the transboundary Conejos-Médanos/Mesilla aquifer located between the US and Mexico. This new analyzed information was compared with the isotopic information available in the US Mesilla and US-MX Hueco basins generated by previous works, which described the common origin of the Hueco Bolson and Mesilla Basins aquifers. This study used isotopic analysis to validate the theory of the original formation and interconnectivity of both transboundary basins. This research presents new data of δ18O and tritium, and a comparison with previous published data from other workers, versus the known global meteoric water line (GMWL) and the Rio Grande evaporation line (RGEL). Results show that the groundwater at the transboundary aquifer features an evaporated isotopic signal, which is consistent with referenced published data that discusses the geologic history of aquifer formations at the studied area. This study is important because isotopic studies from the area were nonexistent and because isotopic data can explain recharge scenarios that relate to groundwater quality.

Hydrochemical and environmental isotopes characteristic of groundwater and controlling factors for waters’ chemical composition in the iron–copper mine area of Elazığ, SE Turkey

Abstract: Environmental context Predicting the hydrodynamic structure of water resources based on water chemistry and isotope results is important for understanding their transport and effects on the hydrogeological system. According to the results of this study, hydrogeological characteristics of ground and surface water resources in the Zeryan Stream sub-basin in the iron–copper mining area and their geochemical evolution are mainly controlled by the weathering of silicate and carbonate minerals, and ion exchange. Rationale and hypothesis Groundwater is generally the most important water resource in mine areas, and its circulation processes need to be studied in detail for rational resource exploitation. This work tested the hypothesis that the evolution of groundwater chemistry and recharge by using hydrogeochemical indicators and isotope tracers together are affected by the hydrogeochemical processes that may have taken place during the water-rock interactions in the Zeryan Stream Sub-basin, where the Iron-Copper mine is located. Methodology It used approaches such as hydrochemistry, Piper diagrams, saturation index, ionic ratios, and environmental isotopes to analyze groundwater origin and hydrochemical processes affecting water chemistry. Fifty-seven water samples were collected from 19 points during wet and dry periods. Results Results indicated that the dominance of cations and anions in the mine water follows the trend Mg2+ > Ca2+ > Na+ > K+ and SO42− > HCO3− > Cl−, and most of the water samples are Mg-Ca-HCO3-SO4, Mg-Ca-SO4-HCO3, and Ca-HCO3. Discussion Evaluation of analyzed groundwater chemical data showed that dissolution or precipitation of silicate minerals dominated in the hydrochemical evolution of groundwater, dissolution of carbonate minerals was a secondary process and to a lesser extent, ion exchange processes played a role. The δD and δ18O isotopic contents indicated that the water samples were controlled by local atmospheric precipitation, and affected by secondary evaporation during the recharge process. Tritium levels indicated some well waters are recharged from older groundwater resources from water-rock interaction and residence time. Findings The findings of this study were provided to decision-makers in order to design sustainable implications for groundwater utilization based on the sub-basin.

Role of Stable Isotopes in Groundwater Resource Management

Abstract: Environmental isotopes are naturally occurring elements found in abundance in the environment. The use of stable isotopes is very useful to understand hydrology. The applicability of stable isotope in understanding the groundwater/surface water interaction is widely used for the anisotropic fractured medium. The isotopes of water (hydrogen and oxygen) are always changeable among reservoirs for their spatial and temporal variation. This could happen due to the changes in isotopic composition through kinetic or equilibrium processes. Therefore, the movement of water can be traced by the abundance of hydrogen and oxygen isotopes. The stable isotopes of hydrogen and oxygen in water are always helpful in the tracking of sources of groundwater recharge, interconnections between aquifers, the interaction between the surface and groundwater phases, determination of the groundwater age, source and mechanism of groundwater pollution, groundwater salinization, and to study the effects of evaporation on groundwater systems. Detail investigations of stable isotopic data are always helpful to acquire knowledge on regional groundwater circulation patterns and geochemical processes of an aquifer system. In this chapter, the role of stable isotopes in groundwater resources management has been discussed with a case study carried out in Aland taluk of Kalaburagi district, Karnataka, India.

Investigation the Origins of Groundwater Salinity in Baghdad City by Using Environmental Isotopes and Hydrochemical Techniques

Abstract: The hydrochemical and isotopic techniques have become one of the most popular and successful methods for determining the hydrogeochemical features of groundwater in recent years. A total of 15 samples were collected during wet (March, 2021) and dry (August, 2021) seasons. An approach with major elements (Cl-, Na+, Mg2+, Ca2+, and SO4 2=) and multi-isotope (2H, 18O) are used in this study to solve the geochemical variation of salinity in groundwater in Baghdad. The results of the analysis of groundwater samples in the study area showed that the major cations were Ca2+ and Na+, while the major anion was SO4, Cl, and HCO3. The Ca-SO4 and Ca-Na-Cl-SO4. hydrochemical facies are the dominant hydrochemical facies of groundwater on the Al-Karakh and Al-Russafa sides, respectively. Ca-HCO3 was found to be the dominant hydrochemical facies of the Tigris River. Human activities and geochemical processes may have caused differences in hydrochemical Facies. According to isotope analysis, the study area has multiple sources of salinity. This can be attributed to the effects of natural dissolution of the salt compounds, mixing with sewage, and industrial water sink. The results and data from this work can be used to research groundwater recharge and interaction, as well as to protect groundwater quality.

Environmental isotopes and hydrochemical investigation to evalute the seepage from Dwarege dam reservoir South Iraq (Missan Governorate)

Abstract: In the last few decades, a series of new Hydrological techniques have been developed to help in the assessment of leakage, Seepage and Recharge. The aim of this search is using the environmental isotopes (18O, 2H) combined with Physico-Chemical parameters (EC, Ca2+, Cl- , TDS etc.) have been employed to identify source of Seepage and Leakage pathways within Dwarege Reservoir-South Iraq. It’s the one of important reservoirs in the south of Iraq. In the present study, describes the relationship between the intake water and water dams. Using three types of water, (groundwater, Dwarege Reservoir and after reservoir). The results show that the stable isotopes composition of Groundwater from (-2.50) to ( -2.58%) for ä 18 O and from (–6.13) to ( -6.23%) for äD, respectively. The stable isotopes content of Dwarege reservoir in the studied area ranged from (-2.47%) and (-2.57%) for ä 18 O and from (-7.6%) to (-7.2%) for äD, while the water after Dam recorded (-1.38) for ä 18 O and (-2.27%) for äD, respectively. The hydrochemical facies of groundwater and Dwarege Dam is Ca-SO4 , while the hydrochemical facies of surface water after Dam is Na-Cl, due to the lithology of study area. Based on the result of isotopic values and hydrochemical facies there is interconnection between groundwater and surface water in the study area.

Water Chemistry and O-H-N Stable Isotopes Pattern for Tracing Contaminant Sources

Abstract: Tracing contaminant in surface and groundwater remains an issue of significance. Nitrate is one of the parameters to be monitored identifying the source and biogeochemical transformations of the nitrogen of interest for the management of water resource. Increasing the inorganic nitrogen concentrations in surface waters can be due to upstream discharge or ammonium sewage effluents, leaching from agricultural land, discharge of farm or industrial effluents, and/or seasonal effects. An effective tool to identify the origin of pollutants are the stable isotopes. Environmental isotopes (O-H-N-O) are great tracers for the physical processes affecting water and considered key parameters to assess the origin, path, and history of a water source. Stable water isotopes (δ18O and δ2H) are affected by meteorological processes that provide a specific fingerprint of their origin. The stable isotopes in nitrate (δ15N and δ18O) are fundamental to identifying the sources of nitrate contamination. Theoretical principles of stable isotopes and isotopic effects are discussed.

Isotope-Geochemical Studies of Groundwater in the Zapolyarny Region of the Nenets Autonomous Okrug

Abstract: The aquifer of sandy deposits in the talik zone of the Pechora River valley was studied. The use of information on the distribution of tritium isotopes made it possible to clarify the recharge conditions of groundwater and their genetic structure in different parts of the aquifer. The tritium age of groundwater in coastal wells was 20–25 years, on the basis of which it was concluded that the groundwater that entered the aquifer before 1995–2000 was almost completely replaced. In wells, remote from the river bank, the age of the water is in the range from 20 to 50 years. However, unlike onshore wells, these groundwaters contain “bomb” water and old water that entered the aquifer be- fore 1952. The age of the old water reaches 12.9±2.5 thousand years. It has been established that the ratio between stable 13C and radioactive 14C isotopes of carbon changes with age, indicating an increase in the carbon exchange between dissolved inorganic carbon and soil carbon dioxide caused by permafrost thawing.

Analysis of the Interaction between Lake and Groundwater Based on Water–Salt Balance Method and Stable Isotopic Characteristics

Abstract: To better protect lacustrine ecologies and understand the evolutionary process of lake environments, it is critical to study the interacting mechanisms between lakes and the surrounding groundwater. The Wuliangsu Lake watershed is the largest wetland in the Yellow River basin and is the discharge area of the Hetao Irrigation District (HID), which is one of the three largest agricultural production areas in China. Due to the influence of human activities, the discharge water from the HID has led to the deterioration of the Wuliangsu Lake ecology and the degradation of the lake environment. Based on long-term observation data and water sampling data collected in 2021, a water–salt equilibrium model was used to analyze the recharge rate of groundwater to the lake. The contribution rate of groundwater to lake recharge in the study area was calculated with a Bayesian mixing model by combining D and 18O stable isotope data. Furthermore, the environmental evolutionary process of the lake was also analyzed using the collected water quality data. The results show that channel drainage was the main source of recharge to Wuliangsu Lake, accounting for more than 75%, while groundwater contributed less than 5% of lake recharge. After implementing the ecological water supplement plan, the concentration of various ions in the lake decreased, the concentration of the total dissolved solids (TDS) in the lake decreased from 1.7 g/L in 2016 to 1.28 g/L in 2021, and the ecological environment was improved. The contribution of groundwater to lake recharge was quantitatively analyzed. The results of this study can facilitate the development of vital strategies for preventing the further deterioration of lake water quality and for protecting wetland ecologies.

Using Stable Isotopes To Identify Spatial-Temporal control on Groundwater Recharge Between Lower Zab and Tigris River South of Al-Shirqat City-Iraq.

Abstract: Stable hydrogen and oxygen isotopes were used as natural tracers to identify spatial-temporal control on groundwater wells recharge and basic physico-chemical parameters between lower Zab and Tigris river South of AlShirqat city-Iraq. the search aimed to study the relationships in isotope compositions to evaluate the source of groundwater recharge. Seven wells water samples were analyzed for stable isotopes for two periods, (dry and wet), 2021. There is a special and temporal variations in the distribution of δD and δ 18O values in the studied area, the δD values are distributed from -39.4 to -16.2 ‰, and from -42.2 to -18.14 ‰ in dry and wet periods, respectively, while the δ 18O values are distributed from -7 to -2.83 ‰, and from -7.26 to -3.08 ‰ in dry and wet periods, respectively. The data suggest that the groundwater is sourced mainly from local meteoric water line of Iraq (LMWL) with some interaction between lower Zab and Tigris river.