Isotopes 2H Research Articles

Geochemical Evolution and Groundwater Flow System in Batujajar Groundwater Basin Area, West Java, Indonesia

DOI:10.17014/ijog.7.1.87-104Batujajar and its surrounding areas, situated in the west of the Bandung Basin, are geologically composed of various Tertiary rock formations with complex fold and fault systems. Springs and drilled wells in sandstone aquifers, tuffaceous sand, and tuffaceous breccias mark the development of their aquifer systems. This study aimed to determine the characteristics of the hydrogeochemistry by analyzing major ions and stable isotopes (18O and 2H) of thirty-four hydrogeological objects. The groundwater flow pattern in this area is controlled by northwest-southeast lineament, as indicated by the emergence of springs along the transition zone between areas with high and low lineament density. In order of dominance, the groundwater facies are as follows:Ca-Mg-HCO3>Ca-HCO3>Ca-Na-Mg-HCO3>Na-Ca-HCO3. Hydrochemical evolutions were detected from the change of cations from Ca2+ to Mg2+ and then Na+, and this is believed to be the product of cation exchange and dissolution of silicate minerals. However, evolutions toward anion changes were not apparent yet, meaning that HCO3- ions still prevail, or in other words the groundwater flow system is local. Nevertheless, the geological and hydrogeochemical analyses, along with the relative compositions of stable isotopes, revealed that the groundwater had three systems, namely shallow, intermediate, and deep groundwater flows; all of which were segmented in three subgroundwater basins (Sub-GWB). Aquifer systems with shallow to intermediate groundwater flow were found in Sub-GWB-A, Sub-GWB-B, and Sub-GWB-C, while the other ones with deep groundwater flow system were identified in Sub-GWB-B and Sub-GWB-C.Fracture system has an important role as a connector between recharge system in hilly areas and discharge system in plain areas.

Multivariate Statistical Analysis of Hydrochemical Data and Stable Isotopes of Groundwater Contaminated with Nitrate at Huay Sai Royal Development Study Center and Adjacent Areas in Phetchaburi Province, Thailand

Due to the continuous expansion in agriculture production and industry for many years, groundwater usage has been increasing, with a decrease in groundwater levels in many cases. In addition, in some areas, groundwater quality has degraded due to agrochemical contamination from agricultural areas. The aims of this research pertains to aquifers as follows: (1) to evaluate hydrochemical characteristics of groundwater using multivariate statistical analysis, including principal component analysis (PCA) and hierarchical cluster analysis (HCA), and (2) to integrate the stable isotopes 18O and 2H with hydrochemical data to evaluate the origin of the groundwater and indirectly identify the pollution sources of groundwater contaminated with nitrate (NO3). Water samples were collected from 60 groundwater wells with different hydrogeological characteristics and land use types in both the rainy season (in October) and the summer seasons (in February) in the Cha Am district of Phetchaburi Province. The groundwater was separated into 3 types: Ca-Na-Cl, Ca-Na-HCO3-Cl, and Na-Cl. Two groundwater wells (no. 19 and 41), which were located southeast and southwest of the study area, had relatively high NO3− concentrations (47 mg/L NO3 and 50 mg/L NO3, respectively) that were higher than the groundwater quality standards. These two wells corresponded to the second group that was exposed by HCA. The PCA results revealed the influence of seawater intrusion. Furthermore, multivariate statistical analysis (PC 2) revealed that the NO3− that is mainly released from potassium nitrate (KNO3), for example, during pineapple cultivation, directly contaminated the groundwater system.

Assessing the "two water worlds" hypothesis by stable isotope method: Progress and prospect

According to the two water worlds hypothesis (TWW), there are two independent water pools with different functions in the soil matrix, bound water world used by plants and mobile water world contributed to runoff and groundwater recharge. The TWW hypothesis is different from the original hydrological model that soil water is completely mixed, and is of significance for establishing new hydrological models. Currently, the theorical basis and formation conditions of TWW hypothesis are still unclear, with less reaserch from China. Here, we summarized research process, discrimination method, controversial points and prospect of TWW hypothesis. There are three views regarding the hypothesis: support, partial support, and rejection. All evaluation methods are based on hydrogen and oxygen isotope (2H, 18O) methods, such as direct comparison, precipitation intersection point method, precipitation residual method, and precipitation migration method. The representativeness of isotope samples of bound water and mobile water and the limitation of isotope technology may be the important reasons for different results across all the studies. The development of methods different from stable isotope ones is an important direction of future research. In addition, the theoretical basis of TWW hypothesis remains unclear, which is the most critical issue. The hypothesis is about a continuous ecological hydrological process coupling of precipitation, soil, and vegetation. Multi-disciplinary integration, multi-scale assessment and multi-factor analysis would be the effective ways to study this hypothesis, and would be an important research direction in the field of hydrology and ecology.

Hydrogeochemistry and groundwater flow mechanisms in shallow aquifer in Yaoundé, Cameroon

Abstract Hydrogeochemical processes and flow mechanisms of groundwater in the urban area of Yaoundé were investigated using major chemical constituents, stable isotopes (18O and 2H), and multivariate statistical analysis. Thirty five groundwater samples were collected and analysed for various parameters. Hydrogeochemical evolution visualized with the Gibbs diagram showed that the groundwater is mainly controlled by water–rock interactions. Factor analysis on the other hand identified three major groups of geochemical constituents and showed that weathering and anthropogenic inputs are the dominant factors controlling groundwater chemistry in the study area. Isotopic analyses revealed that oxygen-18 of groundwater (18O = −2.96 ‰ VSMOW) is close to that of rainfall (18O = −2.47), indicating that the groundwater is recharged by rainwater without evaporation. The geogenic composition of urban groundwater in Yaoundé is modified by secondary processes and anthropogenic input.

Isotopic behavior and self-organizing maps for identifying groundwater salinization processes in Jerba Island, Tunisia

The purpose of this study is to assess the groundwater evolution in Jerba Island. This paper also focuses on the relationship between mineralization and anthropogenic activities and the identification of processes controlling groundwater geochemistry. An approach combining the use of water dissolved chemical species, isotopic fingerprint, and the self-organizing maps has been used to understand the behavior of a unconfined aquifer system and to determine the origin of its different contamination sources. In the present work, a geochemical characterization of the coastal aquifer from the unconfined Jerba aquifer, Southeast Tunisia, was carried out, using hydrogeochemical and isotopic (2H and 18O) data, correlation matrix, and self-organizing maps. For this aim, 79 wells were sampled and analyzed. Geochemical modeling and isotopic data demonstrated that seawater intrusion, exchange reactions occurring within the aquifer matrix, and anthropogenic activities were the major processes controlling the groundwater contamination in the island. The isotopic tracers indicate that the increasing salinity in the shallow coastal aquifer is caused by seawater intrusion. The methodology appears as a valid tool applicable in other coastal areas to determine the main factors governing the groundwater mineralization.

Seasonal effects of intercropping on tree water use strategies in semiarid plantations: Evidence from natural and labelling stable isotopes

Intercropping in plantations can improve ecosystem services, but its potential effects on trees’ water use and production are concerns due to increases in water scarcity related to climate change. The aim of this study was to address these concerns by exploring water uptake responses of jujube (Ziziphus jujuba Mill.) trees to intercropping and extremely dry periods on the semi-arid Loess Plateau of China. Natural stable isotopes (2H and 18O) were analysed to characterize water use patterns of jujube trees and intercrops in the main tree and crop root overlap layer (ROL, 0–120 cm). 10% stable deuterated water was injected at three targeted depths (2, 3 and 4 m) to characterize the water uptake of jujube trees below the main root overlap layers (BOL). In ROL, intercropped jujube trees obtained higher proportions of water in shallower and deeper layers than monocultured jujube trees during wet and dry periods, respectively. Proportional contributions of soil layers to the trees’ water uptake were positively correlated with the layers’ water amount ratios (relative to the entire profile) in intercropped orchards but not in monoculture. In some extremely dry periods, intercropping resulted in jujube trees absorbing deeper water (up to 3 m) in BOL. At the early stage of land-use change from plantation to agroforestry, intercrops induce jujube trees to absorb higher proportions of water from soil layers with high proportions of total water contents in ROL. The soil water in BOL is an important buffer for maintaining water supplies for tree growth in agroforestry systems in case of extreme drought.

Using geochemical and isotopic tracers to characterize groundwater dynamics and salinity sources in the Wadi Guenniche coastal plain in northern Tunisia

Northeastern Tunisia is a sub-humid region with annual rainfall ranging from 600 to 650 mm. Unconfined groundwater in this area is easily accessible and represents an important perennial water source for agricultural activities. The present study deals with a multi-parameter investigation of one of the most important basins in northeastern Tunisia: the Wadi Guenniche plain (130 km2). Hydrochemical (major elements and Br−) and isotopic (18O, 2H and 3H) investigations were carried out on 32 shallow wells to gain insights into groundwater recharge and salinity. The dominant water types were Ca–Mg/Cl–SO4 and Na/Cl with electric conductivity values varying between 0.86 and 6.6 mS/cm. Based on ion ratios and saturation indexes, groundwater salinity originated from weathering of carbonate and evaporite minerals and cation-exchange with clays. Additional influence of anthropogenic activities shown by high NO3− concentrations exceeding 100 mg/L was identified in different parts of the plain resulting from irrigation return flow. A six-year record of 18O and 2H signatures of daily rainwater (n = 293) enabled to define a Local Meteoric Water Line for the Bizerte area (δ2H = 7.02 δ18O + 8.27). The isotopic signature of groundwater was very similar to that of the mean annual rainfall in Bizerte suggesting direct recharge of the aquifer. Tritium levels in sampled wells were relatively high and indicated recent recharge and short residence time. Annual recharge of 100 mm was estimated using a mixing model based on 3H contents in precipitation and groundwater.

Fog Interception Maintains a Major Waterfall Landscape in Southwest China Revealed by Isotopic Signatures

AbstractFog water intercepted by the forest canopy can be an important extra water input for the near‐surface ecosystems in some tropical montane or coastal Mediterranean zones. However, the significance of fog interception on groundwater systems needs to be further studied. An inland subtropical cloud forest in the southwest of China is covered by frequent fog/mist and has thousands of waterfalls with significant flow. To verify the role of fog interception to the local hydrological budget, field investigations and sampling campaigns were carried out over different temporal and spatial scales. Compared with local rainwater, surface water and spring water in the forest were more enriched in 2H and 18O isotopes and had much higher d‐excess, indicating that fog water produced by inland evapotranspiration is a key water supplier. During the dry period, waterfalls are sustained by baseflow, of which a considerable fraction comes from fog interception recharge. The waterfall landscape maintained by fog drip water in this study area represents an example of the important contribution of fog water to some subtropical montane groundwater systems.

Isotopic Study of Springs Near Haditha Dam Western Iraq

Stable isotopic technique and hydrochemistry was used in studying the water resources interaction of near Haditha Reservoir area, western Iraq. Throughout the study area, 14 groundwater samples (Bashina, Zwachi springs and Wells), 8 surface water samples from the study area, and 7 spring samples were analyzed for 2H and 18O stable isotopes and hydrochemical analysis. In this study, the temperature, altitude and continental effects on the isotopic composition of rain water in Iraq were studied. The climate of the study area is classified as semi-arid to arid region. The results show a variation in the isotopic values of Haditha reservoir and Euphrates river. This variation is due to the effect of the low surface area and the low velocity of water of Haditha Reservoir on the amount of evaporation, compared with the high velocity and the large surface area of Euphrates river. There was a variation in the isotopic values between Bishina and Zwachi springs, due to two factors that appear to modify the isotopic signatures of the springs, namely the lack of hydraulic connection between the springs of Bishina and Zwachi, meaning that they recharge from different sources. The changes in oxygen isotope composition of the groundwater between a deep reservoir and the springs (Bishina) may be caused by the dilution with near surface waters (Haditha reservoir) with different oxygen isotope compositions. The variation in the isotopic content in the studied area indicated that there are various origins of springs recharge and a different interactions of the multiple sources of springs with the mutli-depths of springs water.

Accelerated Hydrogen Diffusion and Surface Exchange by Domain Boundaries in Epitaxial VO2 Thin Films.

Electronic phase modulation based on hydrogen insertion/extraction is kinetically limited by the bulk hydrogen diffusion or surface exchange reaction, so slow hydrogen kinetics has been a fundamental challenge to be solved for realizing faster solid-state electrochemical switching devices. Here we accelerate electronic phase modulation that occurs by hydrogen insertion in VO2 through vertically aligned 2D defects induced by symmetry mismatch between epitaxial films and substrates. By using domain-matching epitaxial growth of monoclinic VO2 films with lattice rotation and twinning on hexagonal Al2O3 substrates, the domain boundaries naturally align vertically; they provide a "highway" for hydrogen diffusion and surface exchange in VO2 films and overcome the limited rates of bulk diffusion and surface reaction. From the quantitative analysis of the deuterium (2H) isotope tracer exchange, it is confirmed that the tracer diffusion coefficient (D*) and surface exchange coefficient (k*) were increased by several orders of magnitude in VO2 films that had domain boundaries. These results yield fundamental insights into the mechanism by which mobile ions are inserted along extended defects and provide a strategy to overcome a limitation to switching speed in electrochemical devices that exploit ion insertion.

Spatial and temporal 2H and 18O isotope variation of contemporary precipitation in the Bale Mountains, Ethiopia

ABSTRACTEast Africa is an underrepresented region in respect of monitoring the stable isotopic composition of precipitation (δ18Oprec and δ2Hprec). In 2017, we collected precipitation samples from ten weather stations located along an altitudinal transect ranging from 1304 to 4375 m a.s.l. The δ18Oprec and δ2Hprec values varied from –8.7 to +3.7 ‰ and –38 to +29 ‰, respectively. The local meteoric water line is characterised by a lower slope, a higher intercept and more positive d-excess values (δ2H = 5.3 ± 0.2 * δ18O + 14.9 ± 0.9) compared to the global meteoric water line. Both altitude and amount of precipitation clearly correlate with our isotope data. However, the δ18Oprec and δ2Hprec values show at the same time a seasonal pattern reflecting rainy versus dry season. More enriched isotope values prevailed shortly after the end of the dry season; more depleted isotope values coincided with high precipitation amounts recorded in May, August and September. Moreover, HYSPLIT trajectories reveal that during the dry season water vapour originates primarily from the Arabian Sea, whereas during the wet season it originates primarily from the Southern Indian Ocean. These findings challenge the traditional amount effect interpretation of paleoclimate isotope records from East Africa and rather point to a previously underestimated source effect.

Definition of groundwater genesis and circulation conditions of the complex hydrogeological karst system Mlava–Belosavac–Belosavac-2 (eastern Serbia)

The complex karst system named Mlava–Belosavac–Belosavac 2 is one of the five systems isolated according to detailed research conducted within the Beljanica karst massif which belongs to the Carpatho-Balkanides. In order to define the genesis of groundwaters from these three springs, the deepening of the main karst channel, as well as their underground connection, a multiparameter approach has been applied consisting not only of hydrological, hydrochemical and detailed isotope research methods (stable isotopes 18O, 2H and 13C, as well as radioactive 3H and 3H + 3He isotopes), but also of cave diving exploration of the Mlava Spring. This method was performed in order to define the morphology of the main karst channels and its spatial position. The obtained results have shown that these three springs belong to the same karst system (they have the same recharge zone and relatively similar hydrochemical and isotopic characteristics, and any deviation is a consequence of a different mean residence time that water spent underground), that emerge to the surface along the contact line with hydrologic barriers through karst channels that have different depths. Also, the research has confirmed that the karst channels have well-developed systems of channels in the vertical profile, with a dominant development of deep syphonal circulation.

A conceptual model for water resources circulation patterns in Andarokh-Kardeh region (NE, Iran)

Andarokh-Kardeh region is located northeast of Iran and provides notable part of potable water of Mashhad, the second most populated city of Iran with over 3 million inhabitants. Stable isotopes (18O, 2H and 13C), hydrodynamic, and hydrochemical indicators have been applied to evaluate water resources quality comprehensively and to present a hydrogeological conceptual model for the Andarokh-Kardeh region. Hydrochemical studies indicate that chemical rock weathering and ion exchange are the main factors controlling the quality of water in the region, while atmospheric (precipitation) as well as anthropogenic sources have no notable effect. Stable isotopes (18O and 2H) studies in surface and groundwater samples demonstrate enriched values in Kardeh Dam Reservoir (KDR) due to evaporation and also demonstrate that the interaction between KDR and downstream groundwater resources is negligible. The δ13C isotope and DIC and DOC concentrations indicate role of carbonate mineral dissolution from Mozdooran Formation, atmospheric and soil CO2 and also the domination of C3 vegetation coverage in the study region. The developed conceptual model for Andarokh-Kardeh demonstrates different hydrogeological conditions during wet and dry periods, and highlights the main process which affect hydrogeology of the region. Water quality studies and the developed conceptual model demonstrate the main factors controlling water quality and the main hydrogeological characteristic of Andarokh-Kardeh region which can be used by water resources scientists for the future water management programmes.

Origin of spring waters employing a multiparametric approach with special focus on stable isotopes 2H and 18O in the Lagoa Santa Karst region, Southern Brazil

ABSTRACTKarst environments have an inherent complexity that interferes with their hydrogeology comprehension. Hence, isotope hydrology can be a valuable tool to assess trajectory of subsurface flows in an unexplored setting. The study area is located in the Lagoa Santa Karst, an environmental protection area of great economic, cultural and ecological importance, where Neoproterozoic metalimestones accommodate karst-fractured aquifers, characterized by complex water dynamics, essential vulnerability and high productivity. The purpose of this study was to investigate groundwater flow origins of springs using principally environmental stable isotopes 2H and 18O. Rainwater and spring water were sampled and analysed. The LMWL presents angular and linear coefficients strongly similar to those of the GMWL. Spring isotopic signatures, which represent the base flow and present wide-ranging of 2H and 18O, were separated into two groups. The first group can be associated with recent rainwater major contributions, while the second group shows significant evaporated water contributions, largely represented by resurgences. Tritium concentration and physico-chemical parameter data supported this interpretation, pointing that waters of the second group remained more time on the surface and subsurface. Therefore, using isotope tracers to evaluate upper groundwater zone in this tropical karst system is a powerful instrument for water resources management.

Body composition-derived BMI cut-offs for overweight and obesity in ethnic Indian and Creole urban children of Mauritius.

It is increasingly recognised that the use of BMI cut-off points for diagnosing obesity (OB) and proxy measures for body fatness in a given population needs to take into account the potential impact of ethnicity on the BMI-fat % relationship in order to avoid adiposity status misclassification. This relationship was studied here in 377 Mauritian schoolchildren (200 boys and 177 girls, aged 7-13 years) belonging to the two main ethnic groups: Indian (South Asian descent) and Creole (African/Malagasy descent), with body composition assessed using an isotopic 2H dilution technique as reference. The results indicate that for the same BMI, Indians have more body fat (and less lean mass) than Creoles among both boys and girls: linear regression analysis revealed significantly higher body fat % by 4-5 units (P < 0·001) in Indians than in Creoles across a wide range of BMI (11·6-34·2 kg/m2) and body fat % (5-52 %). By applying Deurenberg's Caucasian-based equation to predict body fat % from WHO-defined BMI thresholds for overweight (OW) and OB, and by recalculating the equivalent BMI values using a Mauritian-specific equation, it is shown that the WHO BMI cut-offs for OB and OW would need to be lowered by 4·6-5·9 units in Indian and 2·0-3·7 units in Creole children in the 7-13-year-old age group. These results have major implications for ethnic-based population research towards improving the early diagnosis of excess adiposity in this multi-ethnic population known to be at high risk for later development of type 2 diabetes and CVD.

The main controls of the precipitation stable isotopes at Kathmandu, Nepal

Precipitation stable isotopes (2H and 18O) are adequately understood on their climate controls in the Tibetan Plateau, especially the north of Himalayas via about 30 years’ studies. However, knowledge of controls on precipitation stable isotopes in Nepal (the south of Himalayas), is still far from sufficient. This study described the intra-seasonal and annual variations of precipitation stable isotopes at Kathmandu, Nepal from 10 May 2016 to 21 September 2018 and analysed the possible controls on precipitation stable isotopes. The enriched δD and δ18O values were identified during non-monsoon season and depleted values were found during monsoon season, showing remarkable intra-seasonal characteristics of monsoon influence. The local meteoric water line suggested a strong influence of evaporation during rainfall in non-monsoon season and significant impact of non-equilibrium processes on precipitation during monsoon season. Temperature–δ18O exhibited negative correlation for overall samples and showed no significant correlation in seasonal scales, which was attributed to the influence of monsoon moisture. The positive correlation was observed between δ18O and outgoing longwave radiation (OLR) in monsoon season, suggesting the significant impact of convective activity on temporal variations of precipitation stable isotopes. During April, and May of 2016 and 2017, variation of precipitation stable isotopes are probably related with the mixing of multi-moisture combined with the westerlies transport. Our study suggested that the moisture transport processes are the main controls of precipitation stable isotopes at Kathmandu.

Preparation of Bacterial Outer Membrane Vesicles for Characterisation of Periplasmic Proteins in Their Native Environment.

Bacterial outer membrane vesicles (OMVs) are naturally formed by budding from the outer membrane of Gram-negative bacteria. OMVs consist of a lipid bilayer identical in composition to the original outer membrane and contain periplasmic content within their lumen. Enriched with specific envelope proteins, OMVs make for an excellent native-like platform to study these proteins in-situ using biophysical methods. Here, we describe in detail the preparation of OMVs from Escherichia coli, which are luminally enriched with periplasmic proteins and uniformly labeled with stable isotopes (2H and 15N), suitable for the subsequent characterisation of proteins at atomic resolution in their native environment by solution-state NMR spectroscopy. The ability to perform structural studies of periplasmic components in-situ clears the way to reaching an in-depth understanding of the functional and mechanistic details of this unique cellular compartment.

A generalized any‐particle propagator theory: Calculations of nucleon's binding energies

AbstractGeneralized one‐particle propagator calculations were performed for fermions in atoms: neutrons, protons, and electrons. For this purpose, multicomponent Hartree‐Fock equations were implemented using Gaussian basis sets where, for nucleons, we consider a non‐Coulombic interaction, through a two‐term Yukawa scalar potential and the interaction between electrons and the electrons with positive charge (protons) through a Coulombic potential. The strategy for evaluating the required interaction integrals follows Obara‐Saika and Head‐Gordon recurrence relations combined with the generalized Boys function suggested by Ten‐no. Calculations on the isotopes 2H, 3H, 3He, 4He, 6Li, 6Be, 7Li, and 8Be were realized to test the accuracy of Koopmans' approximation and a second‐order generalized one‐particle propagator. Yukawa potentials were parametrized to reproduce nuclear properties as kinetic energies and radial distributions of density. These potentials produced the reference nuclear Hartree‐Fock calculations on which fully ab initio propagator calculations were performed for these non‐Coulombic potentials. This allowed us to explore the electronic structure of isotopes in an extended nucleus context.

Identification of groundwater origin using environmental isotopes (18O and 2H) in the upper catchment of Ikopa, district Antananarivo

The upper catchment of Ikopa has great potential for surface or sub-surface water resources. The Ikopa River plays an important role in the water supply of the plain of Antananarivo. Knowing that surface water is abundant but exposed to the high risk of pollution, and groundwater remains less exploited because of the insufficiency of the study concerning the recharge and the sources of their mineralization. The objective of this research is to use the isotope method to characterize groundwater to determine their origin and recharge process. The results of chemical analysis show three different facies type of groundwater which dominated by the sodium, nitrate and chloride ions. The isotopic compositions of the waters sampled vary respectively from -7.25‰ to 5-.09‰ for δ18O and from -46.9‰ to -24.7‰ for δ2H. water form the lakes are more enriched compared to those rivers and groundwater. The diagram δ18O- δ2H shows that groundwater is recharged from local rainwater but undergoes low evaporation before infiltration. However, the results obtained from the parameters measured in situ show that a lateral recharge of groundwater from the streams feeds the neighboring aquifers. Lakes are fed by run-off during the rainy season.

Contribution of water geochemistry and isotopes (δ18O, δ2H, 3H, 87Sr/86Sr and δ11B) to the study of groundwater flow properties and underlying bedrock structures of a deep landslide

A comprehensive understanding of bedrock lithology and groundwater circulation is necessary to identify areas prone to landslide initiation and reactivation. This necessity is particularly required in the case of outcroppings of weak rocks such as gypsum that, due to their high solubility and low mechanical strength, can promote slope deformation with the development of caves and collapses. In the Upper Secchia River Valley, where gypsum outcrops extensively and is covered by landslide deposits, an accurate identification of the gypsum outcrops and their distribution is needed to reduce the damage to urbanized slopes. In this paper, a hydrologic and geochemical approach is used in the Montecagno landslide to identify the origin, flow paths and transit time of groundwater circulating inside the landslide body and to identify gypsum deposits and their distribution in the bedrock. The results of groundwater-level monitoring, δ18O-δ2H and 3H isotope analyses and FLOWPC modelling suggest a local and recent origin of the groundwater hosted in shallow flow paths inside the landslide. Chemical and isotope (87Sr/86Sr, δ11B) analyses offer evidence of the presence inside the landslide of small blocks of gypsum that, due to their dimensions, probably have a minor influence on landslide stability. This research demonstrates that the methodology used can provide satisfactory information about bedrock structures and their hydrological aspects.