Special Issue "Geochemistry of Groundwater"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydrology and Hydrogeology".

Deadline for manuscript submissions: closed (31 December 2020).

Special Issue Editor

Dr. Paolo Madonia
E-Mail Website
Guest Editor
Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Roma 2, Roma, Italy
Interests: hydrology; groundwater; geochemistry; isotopes; seismology; volcanology; spatial analysis

Special Issue Information

Dear Colleagues,

Groundwater is a complex and intriguing geosystem ubiquitously diffused on Earth. It is the main source of water for humankind and the place where meteoric and deep fluids mix, carrying information about geodynamic processes acting at deeper levels of the lithosphere. Its equilibria are affected by quantitative and qualitative pressures, such as pollution, overexploitation, and alterations of the hydrological cycle driven by climatic changes. Geochemistry is a powerful tool for investigating resistance/resilience of groundwater to such changes.

This Special Issue of Water calls for contributions on these subjects, with a particular focus on the geochemical proxies of both anthropogenic and geogenic processes altering the current equilibria of groundwater. A non-exhaustive list of possible contributions includes recent advances in geochemical modeling of groundwater; new equipment and methods for the near-continuous monitoring of geochemical parameters of groundwater; transport and fates of minor, trace, and ultra-trace elements in groundwater; water–rock and meteoric–deep fluid interaction processes in active seismic and volcanic areas; transport and fate of pollutants in groundwater; geochemical proxies of sea intrusion in coastal aquifers; spatial modeling and mapping of geochemical parameters of groundwater; isotopic signature of groundwater, and associated meteoric recharge, as a tool for reconstructing groundwater circulation schemes; and the chemical and isotopic signature of gas phases dissolved in groundwater, with a special focus on active seismic and volcanic areas.

Dr. Paolo Madonia
Guest Editor

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Keywords

  • earthquakes
  • geochemistry
  • groundwater
  • hydrogeology
  • heavy metals
  • isotopes
  • pollution
  • rare earth elements
  • volcanoes
  • water resource management

Published Papers (11 papers)

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Research

Article
Hydrochemical and Isotopic Characterization of the Waters of the Manglaralto River Basin (Ecuador) to Contribute to the Management of the Coastal Aquifer
Water 2021, 13(4), 537; https://doi.org/10.3390/w13040537 - 19 Feb 2021
Viewed by 793
Abstract
Coastal aquifers are strategic and fundamental in the development of touristic areas. The coastal aquifer within the Manglaralto River Basin in Ecuador is essential, as it is the only source of water supply for a large part of the northern part of the [...] Read more.
Coastal aquifers are strategic and fundamental in the development of touristic areas. The coastal aquifer within the Manglaralto River Basin in Ecuador is essential, as it is the only source of water supply for a large part of the northern part of the Santa Elena province. It is a semi-arid region where high volumes of water are pumped from the aquifer, causing a significant drawdown of groundwater levels, thus affecting the water quality. This work aims to characterize the characteristics of groundwater in the coastal aquifer using hydrochemistry and stable isotopes to propose a hydrogeological conceptual model. The methodology for determining the chemical and isotopic characteristics of groundwater follows the following scheme: (i) studies of ionic concentrations using the Piper diagram, (ii) assessment of the origin of salinity through the Cl/Br ratio, the presence of seawater intrusion through the Hydrochemical Facies Evolution Diagram HFE-D, (iii) characterization of precipitation events using stable isotopes (18O and 2H), and, (iv) development of a hydrogeological conceptual model of the study area. The results indicate that in the basin there are mixing processes of the existing water in the aquifer with recharge water, direct cation exchange processes in the freshening process during recharge, and evaporation in the unsaturated zone. A conceptual model of the flow system in the basin is built, based on the mentioned processes. The main conclusions are: seawater intrusion is present in the areas of the wells located closest to the coast, urban activity through septic tanks is affecting the quality of the aquifer, and rainfall is highly relevant in the different hydrochemical and isotopic processes that operate in the basin. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Hydrogeological and Geochemical Characteristics of the Coastal Aquifer of Stromboli Volcanic Island (Italy)
Water 2021, 13(4), 417; https://doi.org/10.3390/w13040417 - 05 Feb 2021
Cited by 1 | Viewed by 515
Abstract
Although groundwater is a strategic source in volcanic islands, most hydrogeochemical research on this topic has been focused on volcanic activity monitoring, overlooking general hydrogeological aspects. The same applies to one of the most studied volcanoes in the world, Stromboli Island (Italy). Here, [...] Read more.
Although groundwater is a strategic source in volcanic islands, most hydrogeochemical research on this topic has been focused on volcanic activity monitoring, overlooking general hydrogeological aspects. The same applies to one of the most studied volcanoes in the world, Stromboli Island (Italy). Here, we provide a hydrogeological scheme of its coastal aquifer, retrieving inferences about its potential use as a water supply source and for optimizing monitoring protocols for volcanic surveillance. Starting from the hydrogeochemical literature background, we analyzed new data, acquired both for volcano monitoring purposes and during specific surveys. Among these, there were saturated hydraulic conductivity measurements of selected rock samples and precise determinations of water table elevations based on GNSS surveys of wells. We identified a ubiquitous thin lens of brackish water floating on seawater and composed of a variable mixing of marine and meteoric components; inlets of hydrothermal fluids to the aquifer are basically gases, mainly CO2. Based on its hydrogeochemical character, the coastal aquifer of Stromboli could be used as a water supply source after desalinization by reverse osmosis, while the wells located far from the seashore are the most interesting for volcano monitoring, because they are less disturbed by the shallow geochemical noise. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Essential Trace Elements and Arsenic in Thermal Springs, Afghanistan
Water 2021, 13(2), 134; https://doi.org/10.3390/w13020134 - 08 Jan 2021
Viewed by 834
Abstract
Thermal springs are natural hydrogeological features which are highly affected by local volcanism or tectonic activity. Thermal springs are the best source of hydrothermal energy to heat houses and aid in the recovery of skin diseases. However, they consist of some heavy and [...] Read more.
Thermal springs are natural hydrogeological features which are highly affected by local volcanism or tectonic activity. Thermal springs are the best source of hydrothermal energy to heat houses and aid in the recovery of skin diseases. However, they consist of some heavy and trace metals such as arsenic, lead, zinc, copper, iron, and so forth. Somehow, the thermal springs of central Bamyan have become contaminated with some essential trace elements. Thus, this study was conducted to assess and determine the number of these trace elements in the thermal springs. To achieve these objectives, a preliminary survey, water sampling, and in situ measurements of physicochemical parameters were conducted in research areas. All the collected water samples were analyzed chemically to determine the amount of trace elements, including arsenic, barium, copper, iron, manganese, and zinc. The study shows that temperature ranged from 16 to 32 °C, while the average pH value was 6.25. Almost all of the trace elements showed an extremely high value of electrical conductivity (average: 5713 µS/cm) and significantly high total dissolved solids (average: 3063 mg/L). The average value of chloride was 797 mg/L, which is dramatically higher than standard values. In regard to trace element concentration, almost all thermal springs were heavily contaminated with arsenic and it was recorded as 100 µg/L in the eastern part of central Bamyan. The average amounts of barium, copper, iron, manganese, and zinc were 4.14, 6.05, 1.90, 1.76, and 0.74 mg/L, respectively. In conclusion, the water of the thermal springs of central Bamyan are not suitable for human consumption because of the significant amount of trace elements as well as the high-water quality index value. Using these springs for drinking and irrigation purposes has been deemed inappropriate. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Groundwater Isotopes in the Sonoyta River Watershed, USA-Mexico: Implications for Recharge Sources and Management of the Quitobaquito Springs
Water 2020, 12(12), 3307; https://doi.org/10.3390/w12123307 - 24 Nov 2020
Cited by 2 | Viewed by 897
Abstract
Groundwater resources in the southwestern United States are finite and riparian and wetland areas are vulnerable to aquifer overdraft and unregulated groundwater use. Environmental isotopes and water chemistry were used to distinguish water types, recharge mechanisms, and residence time along several reaches of [...] Read more.
Groundwater resources in the southwestern United States are finite and riparian and wetland areas are vulnerable to aquifer overdraft and unregulated groundwater use. Environmental isotopes and water chemistry were used to distinguish water types, recharge mechanisms, and residence time along several reaches of the Sonoyta River and Quitobaquito Springs located near the U.S.-Mexico border. Areas located upgradient from the Sonoyta River, such as the Puerto Blanco Mountains and La Abra Plain, are supported by local recharge which corresponds to water from the largest 30% of rain events mainly occurring during winter. For Quitobaquito Springs, the δ18O and δ2H values are too low to be derived from local recharge. Stable isotope data and Cl/SO4 mass ratios indicate that the Sonoyta River supplied Quitobaquito Springs through flow along a suggested fault system. Based on these results, Quitobaquito Springs flow could be diminished by any activity resulting in increased groundwater extraction and lowering of water elevations in the Sonoyta River regional aquifer. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Groundwater Chemistry and Stratification in the Flooded Hard-Coal Mine Shaft “Nowy I” (Nowa Ruda Region, SW Poland)
Water 2020, 12(11), 3257; https://doi.org/10.3390/w12113257 - 20 Nov 2020
Cited by 1 | Viewed by 629
Abstract
The flooding of unprofitable underground mines is one of the methods of their closure. After the drainage of the mine has stopped, the voids left in the rock mass as a result of mining, are filled with inflowing groundwater. In this way, reservoirs [...] Read more.
The flooding of unprofitable underground mines is one of the methods of their closure. After the drainage of the mine has stopped, the voids left in the rock mass as a result of mining, are filled with inflowing groundwater. In this way, reservoirs of groundwater with specific physicochemical parameters are formed. These parameters depend on the interaction of the water flowing into the workings with the rock formations. It was the economic situation in the 1990s that led to the closure of hard coal mines in the Nowa Ruda Coal Basin, where the flooded “Nowy I” shaft is located. In that shaft, in 2008, hydrogeological research was performed and groundwater samples from five various depths were collected. The aim of the study was to recognize if groundwater stratification occurs in the shaft. In 2015, a sample of the water outflowing through the “Aleksander” adit was taken to check the potential influence of mine flooding on the environment and to confirm the changes in groundwater chemistry over time. These were the first, and so far, the only studies on the chemical composition of water in the flooded mine in that area. The article presents results of the preliminary research, which confirmed the existence of not obvious hydrogeochemical stratification in the shaft. It can be assumed that below the depth of 350 m, the water circulating through mining excavations exhibits the highest electrical conductivity and the highest concentration of Ca2+, K+, SO42, Fetot. In the depth range of 320–380 m there is a transition zone, in which a decrease of Eh value and a change of reduction and oxidation is recorded. Above this zone, infiltration water inflow, from outside the shaft casing, dominates. The research shows that it would be necessary to perform additional sampling of the water in the shaft at greater depths, as well as to perform isotope analysis and periodical tests for at least several years. This would allow for a more complete characterisation of hydrogeochemical processes taking place in the flooded mine. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Hydrochemical and Stable Isotope Characteristics of Lake Water and Groundwater in the Beiluhe Basin, Qinghai–Tibet Plateau
Water 2020, 12(8), 2269; https://doi.org/10.3390/w12082269 - 12 Aug 2020
Viewed by 711
Abstract
Thermokarst lakes are a ubiquitous landscape feature that impact the thermal state, hydrological process, ecological environment, and engineering stability of the permafrost. This study established the hydrochemistry and stable isotope (δ18O and δD) variations of lake water and groundwater in a [...] Read more.
Thermokarst lakes are a ubiquitous landscape feature that impact the thermal state, hydrological process, ecological environment, and engineering stability of the permafrost. This study established the hydrochemistry and stable isotope (δ18O and δD) variations of lake water and groundwater in a typical basin located in the central Qinghai–Tibet Plateau (QTP) of China. The results showed that most water samples could be classified as slightly alkaline, with high levels of salinity and hardness, while the dominant water types were HCO3-CO3 and Cl types. Natural hydrochemical processes, such as mineral dissolution, cation exchange, and groundwater evaporation, had strong impacts on the groundwater chemistry in this region. Dissolution of halite and carbonate minerals causes the major reactions controlling water chemistry in this basin. Additionally, the calculation of the saturation index (SI) values suggested that aragonite, calcite, and dolomite are saturated, while halite is not. Based on the analysis of the stable isotope characteristics, atmospheric precipitation, groundwater, and meltwater from the permafrost are the major sources of thermokarst lakes. Moreover, the evaporation-to-inflow ratio (E/I) indicated that all of the lakes continuously expanded and rapidly developed. Overall, groundwater is an crucial source of lake recharge and its hydrochemical characteristics also have a certain impact on lake water quality. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Analytical Method for Lithium Isotopes Determination by Thermal Ionization Mass Spectrometry: A Useful Tool for Hydrogeochemical Applications
Water 2020, 12(8), 2182; https://doi.org/10.3390/w12082182 - 03 Aug 2020
Viewed by 868
Abstract
The low temperature realm such as the geothermal systems, characterized by a large variety of near-Earth surface processes, has been the object of several isotopic studies, some of them including lithium isotopes. However, much work can still be done to systematically use lithium [...] Read more.
The low temperature realm such as the geothermal systems, characterized by a large variety of near-Earth surface processes, has been the object of several isotopic studies, some of them including lithium isotopes. However, much work can still be done to systematically use lithium as tracer of geochemical processes in deep and shallow Earth reservoirs. A pilot study has been performed for the determination of lithium-isotope ratio by thermal ionization mass spectrometry (TIMS), a technique poorly employed with respect to other methods such as inductively coupled plasma mass spectrometry, being more time consuming. Lithium has been extracted by chromatographic techniques on columns through an ion exchange process from both natural and reference samples. The isotope composition (6Li/7Li) expressed in terms of δ7Li has been determined in dynamic and static mode for comparative purposes, by using two different types of thermal ionization mass spectrometers. The results presented in this work agree with the data reported in the literature, opening a new perspective to future research on continental geothermal systems and groundwater domains, spread over the entire Italian peninsula. This research is based on the use of chemical and isotopic data, whereas it does not include lithium isotopes. These latter may provide a huge contribution in studying both volcanic products and fluids from active volcanic areas, including the superposed geothermal systems, and may represent a new tool for research and surveillance. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
CO2 Degassing in Sicily (Central Mediterranean) as Inferred from Groundwater Composition
Water 2020, 12(7), 1959; https://doi.org/10.3390/w12071959 - 10 Jul 2020
Viewed by 589
Abstract
The circulation of groundwater is influenced by several factors, including permeability changes due to the dynamics of the stress field acting along tectonic discontinuities. Open faults can act as preferential pathways for the escape of crustal and subcrustal gases, such as CO2 [...] Read more.
The circulation of groundwater is influenced by several factors, including permeability changes due to the dynamics of the stress field acting along tectonic discontinuities. Open faults can act as preferential pathways for the escape of crustal and subcrustal gases, such as CO2, towards the surface, allowing their chemical interaction with meteoric fluids. Here, we present the first map of dissolved CO2 partial pressure in the groundwater of Sicily, Italy. Based on the chemical analysis of 557 samples of groundwater, which were collected in wells and springs, we calculated the related CO2 partial pressure (PCO2) using PHREEQC software. The spatial distribution of the calculated PCO2 values highlights a general homogeneity at the regional scale, interrupted by positive anomalies linked to the main seismogenic or volcanic areas. Faults work as preferential escape pathways for deep CO2. The subsequent CO2–water–rock interaction determines the chemical composition of circulating water. As a consequence, groundwater composition can be successfully used to identify anomalous degassing areas. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Hydrogeochemical Characters of Karst Aquifers in Central Italy and Relationship with Neotectonics
Water 2020, 12(7), 1926; https://doi.org/10.3390/w12071926 - 06 Jul 2020
Cited by 2 | Viewed by 849
Abstract
Groundwater from karst circulation systems of Central Italy were sampled and analyzed, in 2018, for delineating a preliminary, general geochemical framework of their relationship with neotectonics, in an area characterized by a frequent and often destructive seismicity. We determined field physical-chemical parameters, concentrations [...] Read more.
Groundwater from karst circulation systems of Central Italy were sampled and analyzed, in 2018, for delineating a preliminary, general geochemical framework of their relationship with neotectonics, in an area characterized by a frequent and often destructive seismicity. We determined field physical-chemical parameters, concentrations of main dissolved ions and gases and isotopic composition of water (δ18O, δD) and total dissolved inorganic carbon (δ13C TDIC). We discriminated between “normal” hydro-karst systems and multi-component aquifers, composed of meteoric groundwater that have also interacted with rocks of different lithological nature and/or deep fluids. These multicomponent aquifers are of potential interest in the monitoring of neotectonics activity, because changes in the stress field associated with the preparatory phase of an earthquake may affect the permeability of rocks, in turn causing variation of their chemical-isotopic character. The geographical distribution of these aquifers seems to be controlled by tectonics. In fact, the Olevano–Antrodoco–Sibillini thrust separates the more anomalous sites, located westwards of it, from the groundwater bodies at its eastern side, showing a more typical karst character. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
Hydrochemical Characteristic of Groundwater and Its Impact on Crop Yields in the Baojixia Irrigation Area, China
Water 2020, 12(5), 1443; https://doi.org/10.3390/w12051443 - 19 May 2020
Cited by 2 | Viewed by 793
Abstract
While irrigated crops produce much higher yields than rain-fed crops, the ionic components of irrigation water have important effects on crop yield. Groundwater is widely used for irrigation in the Baojixia irrigation area in China. The chemical characteristics and water quality of groundwater [...] Read more.
While irrigated crops produce much higher yields than rain-fed crops, the ionic components of irrigation water have important effects on crop yield. Groundwater is widely used for irrigation in the Baojixia irrigation area in China. The chemical characteristics and water quality of groundwater in the Baojixia irrigation area were analyzed and evaluated to study the impact of groundwater quality on crop yield. Results showed cations in the groundwater to mainly be Na+, Ca2+, and Mg2+, whereas the anions are mainly HCO3, SO42−, and Cl. Water-rock interaction and cation exchange were identified as the main factors affecting hydrogeochemical properties from west to east. The study found salinity and alkalinity of groundwater in the western region of the study area to be low, and therefore suitable for irrigation. Groundwater in the eastern part of the study area was found to have a medium to high salinity and alkalinity, and is therefore not recommended for long-term irrigation. The groundwater irrigated cultivation of wheat and corn in the research area over 2019, for example, would have resulted in a drop in the annual crop output and an economic loss of 0.489 tons and 0.741 × 104 yuan, respectively. Irrigation using groundwater was calculated to result in the cumulative loss of crop yields and an economic loss of 49.17 tons and 80.781 × 104 yuan, respectively, by 2119. Deterioration of groundwater quality will reduce crop yields. It is recommended that crop yields in the study area be increased by strengthening irrigation water management and improving groundwater quality. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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Article
The Evolution and Sources of Major Ions in Hot Springs in the Triassic Carbonates of Chongqing, China
Water 2020, 12(4), 1194; https://doi.org/10.3390/w12041194 - 22 Apr 2020
Cited by 4 | Viewed by 931
Abstract
Thermal groundwater in the Lower and Middle Triassic carbonates in Chongqing, China, is mainly concentrated in anticlines. Hot springs (32.9 to 57 °C) with SO4-Ca type waters and Total Dissolved Solids (TDS) of 1620 to 2929 mg/L emerge in the middle [...] Read more.
Thermal groundwater in the Lower and Middle Triassic carbonates in Chongqing, China, is mainly concentrated in anticlines. Hot springs (32.9 to 57 °C) with SO4-Ca type waters and Total Dissolved Solids (TDS) of 1620 to 2929 mg/L emerge in the middle and the plunging ends of the structures. Multivariate methods are used to analyze the hydrochemical characteristics of the waters, and identify the sources of the main dissolved components, providing an insight into the evolution of the environment in which they formed. Hierarchical cluster analysis of compositional data differentiates samples in the study area into three categories: high TDS-high Ca2+ and SO42− water; medium TDS-high Na+ and Cl water; and low TDS-high HCO3 water. Factor analysis and ion ratio relationships show that Ca2+ and SO42− are mainly derived from the dissolution of gypsum and anhydrite within the geothermal reservoir, with some addition of SO42− from coal-bearing cap rocks. The main source of HCO3, is in the dissolution of dolomite and CO2 that also promotes the incongruent dissolution of albite and K-feldspar, adding Na+ and K+ to the groundwater. Reverse modelling of the transfers of each phase shows, in three models, that the minerals dissolved decrease progressively—with the exception of halite and albite. Combined with the hydrochemical characteristics of hot water in the same reservoir in the adjacent area (Cl-Na type, TDS of 13.37 g/L), a process of desalination of the hot water can be confirmed, which has not yet reached the ‘freshwater’ stage dominated by HCO3. Full article
(This article belongs to the Special Issue Geochemistry of Groundwater)
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