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In most regions worldwide, the groundwater usage is increasingly common due to the progressive decreasingof the effective availability of surface water for both quantity regime and quality issues, as a consequence ofglobal population increasing, global climate change and growing water pollution. Therefore, groundwater isthe most important and safest source for water supply being less affected by pollution and climate changes.For example, in European Union countries, groundwater provides nearly 70% of the piped water supply and80% of the drinking water. However, the overexploitation of groundwater may sometimes exceed rechargeover long periods and over extensive areas and the subsequent decline in water table level may affect naturalgroundwater discharge and quality, which in turn may have harmful impacts on groundwater dependentstreams, wetlands and ecosystems. For these reasons a correct management of the groundwater resourcesis of paramount importance. In this scenario, groundwater modelling, both conceptual and numerical, isparticularly crucial for the sustainable and efficient management of groundwater resources, even more inthe context of expected climate change.The middle-high Brenta river plain (NW of Veneto, Italy) is characterized by the existence of an importantunconfined to semi-confined foothill aquifer system, that is made of a very thick single-layer of gravellypebbly alluvial deposits, in the northernmost part, whereas in the southern part the aquifer becomes amultilayer composed of gravelly deposits and levels of silt and clay. The existence of an important aquifersystem is tied to the high annual rainfall amount, about 1200 - 1500 mm/year, however the maingroundwater recharge component of the aquifer is related to the water dispersion from the Brenta river.Groundwater hosted in the aquifer represents an important resource for drinkable supply, industrial andagricultural usages. However, over the last decades, the exploitation of groundwater resource and themeteo-climate regime caused a decrement of the piezometric level alerting the local authorities. Thanks tothe existence of a consistent and continuous monitoring network made up of several meteoric, hydrometricand piezometric stations, very long time-series of data are available. The availability of a long time-seriesallowed to develop Data-Driven models, specifically Multiple Linear Regression Models, of the Brenta riverhydrometric level (using rainfall, snowfall and atmospheric temperature as independent variables) and of thepiezometric level of groundwater in the middle-high plain (using atmospheric temperature, the local rainfalland the model of Brenta river as independent variables). The regression models were used to makepredictions on the development of the hydrometric level of Brenta river and consequently of thegroundwater level under extreme weather and climate conditions as those of the last years, thus providinguseful information for steering the best water management practices in a zone where strategic groundwaterexploitation systems are located.

Understanding and quantifying hydrology processes represent a mandatory step in semi-arid and arid regions for defining the vulnerability of these environments to climate change and human pressure, as well as for providing useful data to steer mitigation and resilience strategies. This generally valid concept becomes even more stringent for highly sensitive ecosystems, such as small islands.It is the case of Pianosa Island (Tuscan Archipelago) that extends a few more than 10 km2 within the Tyrrhenian Sea and it is characterised by a flat morphology (maximum altitude 29 m a.s.l.) and semi-arid climate conditions (550 mm and 17 °C as mean annual precipitation and temperature).Because of the morphology and the medium-high permeability of superficial bio-calcarenite rocks, superficial water are absent. Nevertheless, the peculiar geological-hydrogeological setting guarantee a storage of groundwater in a phreatic aquifer and semi-confined/confined system, hitherto able to satisfy the local human water demand, mainly tied to seasonal tourism (thousands of visitors/year) and domestic exigencies (less than 30 permanent people). Evapotranspiration represents the most important voice of the water budget, given the windy and relative high temperature conditions.In the precarious hydro-equilibrium for biosphere and human communities, and considering sea-level rise and climate regime trends that the Mediterranean is experiencing, HYDRO-ISLAND project (UNESCO’s program) intends to deploy a multi-disciplinary approach (geology, hydrogeology, geochemistry, geophysics, remote sensing-smart technology) for better understanding and quantifying the hydrological processes affecting the water availability and for sharing data and transfer knowledge to the community and younger generations, possibly suggesting best practices for water sustainability.First results pointed out as over the last decade the annual rainfall weakly tended to increase, but at the same time such increasing resulted concentrated in summer and autumn seasons, whereas during winter and spring a decreasing tendency is even observed. This precipitation regime has led to a major rate of evapotranspiration and minor effective infiltration that caused a decreasing of piezometric level over several years. Quantity and chemical-isotopic features of rainfall and effective infiltration water measured/collected by a raingauge and a high precision lysimeter describe the hydrological processes at soil level and characterize the rate and seasonality of groundwater recharge in an experimental site. Using multispectral data by drone, we are trying to extend the experimental site information to a wider area in order to understand the general behaviour at island scale. Measurements, water sampling and analyses for shallow and deep wells, together with the study of geological constraints, are highlighting the distribution and relationship among different groundwater components, including the seawater that intrudes the aquifer from the SE side of the island. Furthermore, the comparative analyses of continuative data monitoring in wells and weather station showed the presence of possible concentrated water infiltration processes during rainfall extreme events that induce a quick response of groundwater systems in terms of water level rise and decrease of electrical conductivity. Thus, elements of vulnerability of the aquifer to pollution are pointed out, as well as the possibility to provide technical solutions for enhancing water infiltration and groundwater availability.

Presentation was presented at the Arctic Science Summit Week 2023 (ASSW2023)that took place in Vienna, Austria on February 17-24, 2023 (February 21th, 2023). The presentation includes a synthesis of the published work ofMagnaniet Al.,2022,"Microscale drivers of summer CO2fluxes in the Svalbard High Arctic tundra" (Sci Rep) and subsequent analysis performed onto the 2021-2022 datasets.&nbsp

Non-steady-state closed dynamic accumulation chambers are widely used to measure the respiration of terrestrial ecosystems, thanks to their low cost, low energy consumption and simple transportability, that allow measurements even in hostile and remote environments. However, the assessment of the accuracy and precision associated with the measurement system (independently of possible disturbances due to chamber-soil interactions) is rarely reported. This information is instead necessary for basic quality control, to compare data obtained by different devices and regression models and to provide Confidence Intervals (CIs) on the carbon flux values. This study quantifies the uncertainty associated with emission flux measurements, with a focus on very low fluxes. Calibration tests using different accumulation chambers and CO2 sensors were performed, and fluxes were calculated by means of different models (parametric, non-parametric and flux models). The results of this work show that the linear regression model has the best reproducibility when compared to the other tested models, regardless of the sensor used and the chamber volumes, while the second order polynomial regression has the best accuracy. We remark the importance of building a calibration curve in the range of the expected flux values, with an interval between the lowest and highest imposed flux that should not exceed two orders of magnitude. To evaluate the reproducibility of the measurement, performing replicates for each imposed flux value is essential. We also show that it is necessary to carefully identify the best time interval for interpolating the CO2 concentration curve in order to guarantee reproducibility and accuracy in flux estimates.

In the context of climate change, the correct management of groundwater, which is strategic for meeting water needs, becomes essential. Groundwater modeling is particularly crucial for the sustainable and efficient management of groundwater. This manuscript provides different types of modeling according to data availability and features of three porous aquifer systems in Italy (Empoli, Magra, and Brenta systems). The models calibrated on robust time series enabled the performing of forecast simulations capable of representing the quantitative and qualitative response to expected climate regimes. For the Empoli aquifer, the process-based models highlighted the system’s ability to mitigate the effects of dry climate conditions thanks to its storage capability. The data-driven models concerning the Brenta foothill aquifer pointed out the high sensitivity of the system to climate extremes, thus suggesting the need for specific water management actions. The integrated data-driven/process-based approach developed for the Magra Valley aquifer remarked that the water quantity and quality effects are tied to certain boundary conditions over dry climate periods. This work shows that, for groundwater modeling, the choice of the suitable approach is mandatory, and it mainly depends on the specific aquifer features that result in different ways to be sensitive to climate. This manuscript also provides a novel outcome involving the integrated approach wherein it is a very efficient tool for forecasting modeling when boundary conditions, which significantly affect the behavior of such systems, are subjected to evolve under expected climate scenarios.

This technical note (in Italian) describes how to calibrate portable flux chambers equipped with IRGA for the measurement of CO2 fluxes from soil. An English version is in progress.

The continuous acquisition of CO2 soil flux data has been started on Mt Etna in November 2021, with the aim of assessing a first balance between CO2 from volcanic and biological origin. Our long-term goal is an interdisciplinary study of volcanic, biological, ecological, biogeochemical, climatic and biogeographical aspects, including the anthropogenic impact on the environment. All aspects are integrated in the study of the so-called Critical Zone, i.e. the layer between the deep rock and the top of the vegetation where the main biological, hydrological and geological processes of the ecosystem take place. The new research activity at Mt Etna is performed within the framework of the PON-GRINT project for infrastructure enhancement (EU, MIUR), and it adds up to activities going on at Grand Paradiso National Park (Italian Alps), and Ny Alesund (Svalbard, NO, High Arctic) in the framework of the IGG-CNR Critical Zone Observatories.During the first phase of the project, two fixed stations were installed in two sites at Piano Bello (Valle del Bove, Milo), in an area where the endemic Genista aetnensis grows. An Eddy Covariance system for net CO2 ecosystem exchange measurement and a weather station will be installed in 2022. Carbon stable isotopes data will be acquired periodically using in-situ instrumentation (i.e. Delta Ray). The installation sites are selected after CO2 soil flux surveys around the volcano using a portable accumulation chamber. The two stations installed at Piano Bello consist of an automatic accumulation chamber fixed to the ground, a mobile lid with a diffusion infrared sensor for measuring CO2, a data logger and a sensor for measuring soil moisture and temperature. The accumulation chambers are programmed to acquire data on ecosystem respiration every hour for all day. Data are transmitted to the IGG data collection center. The new IGG-CNR Mt Etna CZO will contribute investigating CO2 fluxes at the soil-vegetation-atmosphere interface in different geological and environmental contexts. We benefit from the collaboration with the National Institute of Geophysics and Volcanology (INGV), the Ente Parco dell'Etna, and the Dipartimento Regionale dello Sviluppo Rurale e Territoriale di Catania.

The Adriatic region is highly vulnerable to the adverse impacts of climate change. Although attention has been paid to understand the climate change impact and risks over the last decades, the Adriatic community still faces a lack of a common risk assessment. For this reason, ASTERIS project has been financed at the Call for proposal 2017 Priority Axis Safety and resilience of Interregional V Italy-Croatia 2014-2020 Program. To this overall objective, the project will provide two main outputs: i) a map of vulnerability to coastal salinization at the macro-regional scale (Adriatic) based on future scenarios for sea-level rise and the hydrological cycle and ii) best practice and guidelines for the management of vulnerable sites defined though the analysis of representative case studies in Italy and Croatia. Within these general purposes, hydrogeological and geochemical surveys in two specific shallow aquifer systems that develop in the coastal areas of Fano and Ravenna (central-eastern Italy), were carried out. Several periodical campaigns, aimed at measuring water level and physical-chemical parameters by vertical logs in wells or piezometers, were also conducted. Additionally, ground and surface water samples were also collected for chemical and isotopic analyses to define the compositional features and the main geochemical processes affecting the two shallow aquifers. Preliminary investigations suggested that the Ravenna shallow aquifer is already strongly spoiled by a significant seawater intrusion (up to 80 %), whereas at Fano the presence of the saline wedge can be regarded as negligible. This indicates that the aquifer system of Fano can be considered as a good proxy for evaluating and simulating potential processes of saline-fresh water interactions by either the increasing demand of water exploitation and sea level rise due to anthropogenic pressure and climate change, respectively. In order to simulate possible future ingressions of seawater in the aquifer system of Fano, groundwater flow and transport models are currently in progress. These models will be implemented and calibrated according to the hydrogeological and geochemical data collected within the framework of the ASTERIS project. The expected modelled scenarios, obtained through predictive simulations, are of pivotal importance for assessing the possible groundwater response to climate change and for a correct management and protection of water resources, which can be exported to other aquifers system along the Adriatic Sea.

Arctic tundra is currently undergoing significant changes induced by the effects of a rapid temperature rise, that in the Arctic is about twice as fast as in the rest of the world. The response of the system composed by the permafrost active layer, soil and vegetation is especially relevant. In fact, it is still unclear whether the system will turn from a carbon sink to a carbon source, owing to the interplay of two opposite phenomena: the increasing time span of the growing season, favouring Net Ecosystem Production (NEP), and the increasing soil temperatures, favouring degradation of organic matter through heterotrophic respiration (HR) and then creating a positive climate feedback. In this work, we analyse soil-vegetation-atmosphere CO2 flux data of a field campaign conducted in the Bayelva river basin, Spitzbergen, in the Svalbard Archipelago (NO) during summer 2019, measured by a portable accumulation chamber. We use a “Critical Zone” perspective, considering the multiple interactions between biotic and abiotic components. We measured the Net Ecosystem Exchange (NEE) and Ecosystem Respiration (ER) along a slope gradient at different degrees of soil humidity and active layer depths, relating flux data to climate and environmental parameters, soil physical-chemical parameters and vegetation type. The statistical empirical relationships between variables are analysed to identify the main drivers of carbon exchanges. An empirical data-driven model is built to describe the coupled dynamics of soil, vegetation, water and atmosphere that contributes to budgeting the carbon cycle in the Arctic Critical Zone. A comparison of the carbon fluxes obtained with the accumulation chamber method and an Eddy Covariance tower located in the same area is also addressed.

Methane (CH4) is an important greenhouse gas, and is increasing in the atmosphere by 0.6% (10 ppb) each year. Important sources of this gas are landfills; in fact more than 10% of the total anthropogenic emissions of CH4 are originated in them by anaerobic degradation of organic matter. Even after years of being closed, a significant amount of landfill gas can be released to the atmosphere through its surface as diffuse or fugitive degassing.Many landfills currently report their CH4 emissions to the atmosphere using model-based methods, which are based on the rate of production of CH4, the oxidation rate of CH4 and the amount of CH4 recovered (Bingemer and Crutzen, 1987). This approach often involves large uncertainties due to inaccuracies of input data and many assumptions in the estimation. In fact, the estimated CH4 emissions from landfills in the Canary Islands published by the Spanish National Emission and Pollutant Sources Registration (PRTR-Spain) seem to be overestimated due to the use of protocols and analytical methodologies based on mathematical models. For this reason, direct measurements to estimate CH4 emissions in landfills are essential to reduce this uncertainty.In order to estimate the CH4 emissions to the atmosphere from landfills in the Canary Islands, 34 surveys have been performed since 1999 to the present. Each survey implies hundreds of CO2 and CH4 efflux measurements covering the landfill surface area. Surface landfill CO2 efflux measurements were carried out at each sampling site by means of a portable non-dispersive infrared spectrophotometer (NDIR) model LICOR Li800 following the accumulation chamber method. Samples of landfill gases were taken in the gas accumulated in the chamber and CO2 and CH4 were analyzed using a double channel VARIAN 4900 micro-GC. The CH4 efflux measurement was computed combining CO2 efflux and CH4/CO2 ratio. To quantify the diffuse or fugitive CO2 and CH4 emission, gas efflux contour maps were constructed using sequential Gaussian simulation (sGs) as interpolation method. Considering that (a) there are 6 controlled landfills in the Canary Islands, (b) the average area of the 34 studied cells is 0.15 km2 and (c) the mean value of the CH4 emission estimated for the studied cells range between 6.2 and 7.2 kt km-2 y-1, the estimated CH4 emission to the atmosphere from landfills in the Canary Islands showed a range of 5.7-6.7 kt y-1 (mean value of 6.2 kt y-1). On the contrary, and for the same period of time, the PRTR-Spain estimates the CH4 emission in the order of 6.4-16.4 kt y-1 (mean value of 9.2 kt y-1), nearly 46% more than our estimated value. This result demonstrates the need to perform direct measurements to estimate the surface fugitive emission of CH4 from landfills.Bingemer, H. G., and P. J. Crutzen (1987), J. Geophys. Res. 92, 2182-2187.

Groundwater systems are typical dissipative structures and their evolution can be affected by non-linear dynamics. In this framework, geochemical and hydrological processes are often characterized by random components mixed with intermittency and presence of positive feedbacks between fluid transport and mineral dissolution. Therefore, in these cases, complex variability structures in the chemical signature of waters are recognized. Large fluctuations in intermittent processes are not rare as in normal and log-normal processes and significantly contribute to the statistical moments, thus moving the physicochemical data from the Euclidean geometry to fractals and multifractals.Since the knowledge of dynamics in water systems has substantial implications in the management of the water resource, groundwater chemistry can better be understood by using innovative graphical and numerical methods in the light of the Compositional Data Analysis Theory (CoDA, Aitchison, 1986), which is particularly suitable to explore the whole composition and the relationships between its parts.The whole compositional change, characterizing each sample with respect to some end-members (i.e. rain waters, pristine waters and sea water), is modeled by using the perturbation operator in the simplex geometry (Pawlowsky-Glahn and Buccianti, 2011). Perturbation factors are calculated and then analyzed by investigating their cumulative distribution function (Pr[X>=x]) with the aim of registering the presence of power laws (fractal and multifractal dynamics) and forecasting a possible spatial behavior.Results obtained for some aquifers from Tuscany (central Italy) are presented and discussed in the framework of the GEOBASI project (Nisi et al., 2016). Preliminary evaluations indicate that perturbation factors are sensible tools to: 1) identify the different components (random, deterministic, fractal) contributing to the variability of the geochemical data, 2) discriminate the role of additive and multiplicative phenomena in time and/or space, 3) highlight the presence of non-linear dissipation with the energy exchanges between different scales.[Office1] Aitchison, J., 1986. The statistical analysis of compositional data. Monographs on Statistics and Applied Probability (Reprinted in 2003 by The Blackburn Press), Chapman and Hall, 416 p.Nisi, B., Buccianti, A., Raco, B., Battaglini, R., 2016. Analysis of complex regional databases and their support in the identification of background/baseline compositional facies in groundwater investigation: developments and application examples. Journal of Geochemical Exploration 164, 3-17Pawlowsky-Glahn, V., Buccianti, A., 2011. Compositional Data Analysis: Theory and applications. Chichester, John Wiley & Sons, 378 p.

In this study, geochemical data processing and statistical/geostatistical techniques were coupled to achieve Water Framework Directive goals, collecting useful information from a complex database. Considering the Greater Turin metropolitan area, located in North-Western Italy, chemical data of 135 wells sampled and collected from 2000 to 2018 by the Environmental Protection Agency of Piedmont were analyzed. Both the processes that determine the groundwater chemical composition and the origin and evolution of groundwater were decoded and understood. The presence of two different components in the foothill aquifer system investigated was found. A bicarbonate alkaline earthy type component, linked with different degrees to phenomena of water-rock interaction, and a chlorinated type component related to nitrates, whose effects related to human activities can be recognized. This last component was mapped by using geostatistical techniques to define the most critical zones of the study area. Time series analysis on chlorides and nitrates displayed the presence of statistically significant increasing trends in some areas of the Turin plain. This study shows that the combining of geochemical approach, geostatistical techniques, and time series analysis can be used as reliable tools to understand geochemical processes acting on the system, to identify temporal and spatial hydrochemical variability, as well as to forecast water quality evolution. In this perspective, the multi-disciplinary approach developed in this study represents a reliable methodology for extracting useful information from a complex database and achieving the Water Framework Directive goals.

In high mountains, the Critical Zone (CZ) is a thin layer sustaining the whole local ecosystem. Here, however, the effects of climate change are manifesting most rapidly than in the surrounding lowlands. This is especially critical for the high-altitude carbon cycle, for which our knowledge is still patchy and new feedbacks could possibly be triggered. In particular, models of the processes that control carbon fluxes in mountain grasslands and Alpine tundra need to be improved. To contribute to fill this knowledge gap, in 2017 a new Critical Zone Observatory was established at the valley of the Nivolet Plain (CZO@Nivolet) in the Gran Paradiso National Park (GPNP), in the western Italian Alps, at about 2700 m asl. Three measurement sites were identified along the flanks of the valley. The sites are characterized by soils developed over carbonate rocks, gneiss rocks and glacial deposits. Since 2017, every year, from July to October, fluxes of carbon dioxide (CO2) were measured using a portable accumulation chamber, together with basic meteo-climatic and environmental variables, such as soil and air temperature and moisture, air pressure and solar radiation. This work is focused on a novel empirical model that uses unbiased and rigorous statistical analysis of these data to identify the environmental variables that control CO2 fluxes in Alpine tundra. The modelling approach is applied to the full dataset of simultaneous in situ measurements of the net exchange, ecosystem respiration and environmental variables for the three sites and the three measurement years. Since a large year-to-year variability in the dependencies on solar irradiance and environmental temperature is observed, a multi-regressive model has been implemented, where additional variables are introduced as perturbations of the standard functions. The multi-regressive model identifies the main drivers, highlighting the crucial role of soil moisture, and largely explains the temporal variability of the fluxes, with explained variance up to 90%. This model provides a basis for estimating future scenarios of carbon fluxes in high-altitude Alpine ecosystems.

The management of groundwater resources has become a matter of public interest during recent years. It is a difficult and sensitive topic for all involved subjects, scientists, state agencies, public and private water supply companies and citizens. Therefore, tools for collection, storage, evaluation and public visualization of groundwater-relevant information have to be constructed and implemented. The development of network-based technologies, and the support of the Geographical Information Systems, would help the dissemination of the knowledge about groundwater chemistry, as well as the integration of the geochemical data with other type of information (geological, hydrogeological, soil use, etc.). However, dedicated repositories often contain fragmented numerical and categorical information from different sources obtained for dissimilar aims and divergent interests, thus compromising a holistic management of the resource. Given the complicated nature of the information related to groundwater and geochemical behavior, statistical methods describing and evaluating data patterns in complex regional databases have to be developed in a dedicated way. An application example is presented for the Geobasi–Tuscany (central Italy) project, a repository where all the information about the geochemistry of natural media, including groundwater, collected in the regional territory is stored. Robust methods, not sensible to anomalous cases, have been associated to the compositional approach, leading to the identification of the baseline compositional facies, related to frequent and spatially diffused geochemical phenomena. The facies have been discriminated from the other ones, related to specific environmental conditions, affecting limited portions of the territory. The methodology can be easily integrated with those based on the classical ternary or square diagrams for the identification of the hydrochemical facies. The proposed robust approach, compositional and, therefore, multivariate, appears to be an efficient way to understand how the natural and not natural processes are working on a regional scale.

Many foothill zones in Italy contain aquifer systems of strategic interest for water supplying, especially for drinking purposes (Doveri et al., 2016). The hydrogeological features in these environments generally promote the infiltration of both local rainfall and seepage from stream water originating in mountain catchments. On the other hand, because of their linkage with mountain areas, these systems are characterized by significant sensitivity towards the meteo-climatic variations and changes. To cope with climate change, a high level of knowledge of this type of aquifer should be reached in order to address the water management issues. This work focus on the aquifer system extending in the foothill plain located in the Piedmont region (NW Italy), between the Western Alps and the Torino Hill (Piana et al., 2017). Taking into account previous studies (De Luca et al., 2014 and references therein) and datasets from monitoring activities institutionally performed by the Environmental Protection Agency of Piedmont Region (ARPA Piemonte), the study examined the geological, hydrogeological and hydraulic-hydrodynamic features of the aquifer, as well as the chemistry of groundwater. This comprehensive approach steered the definition of the aquifer system conceptual model as well as the evolution of groundwater quantity and the chemical quality of groundwater. The statistical analysis performed on datasets highlighted some trends over the lasts two decades, both for groundwater quantity and quality. In particular, a significant sensitivity to meteo-climate conditions was pointed out by high confidence trends of piezometric level decrease occurred over both the periods 2004-2008 and 2010-2017, because of the respective rainfall decrease patterns. The rainy year 2009, which interposed itself between the two relatively dry periods, promoted sharp increases in terms of piezometric levels and concentrations of some chemical compounds in groundwater, thus pointing out as the hydrologic extremes can lead to the accumulation of nutrients and salinity in the unsaturated zone of the aquifer and their successive concentrate release in groundwater.

Many foothill zones in Italy contain aquifer systems of strategic interest for water supplying, especially for drinking purposes (Doveri et al., 2016). The hydrogeological features in these environments generally promote the infiltration of both local rainfall and stream water originating in mountain catchments. On the other hand, because of their linkage with mountain areas, these systems are characterized by significant sensitivity towards the meteo-climatic variations and changes. Hence, a high level of knowledge of the foothill aquifers should be reached for addressing the water management issues by real technical approaches and management actions. This work focus on the aquifer system extending in the foothill plain located in the Piedmont region (NW Italy), between the Western Alps and the Torino Hill (Piana et al. 2017). This area is of scientific interest, since it represents the hydrogeological "transition zone" between the Western Po Plain and the southern Piedmont Plain aquifer systems (Irace et al., 2010). Furthermore, the interest towards these aquifers is tied to the reliance on their groundwater resource for drinking water supply, which is performed by SMAT (Società Metropolitana Acque Torino). In close cooperation with SMAT, which also co-founded the project, and taking also into account previous studies (De Luca et al., 2014; De Luca and Osella, 2014) and datasets from monitoring activities institutionally performed by the Environmental Protection Agency of Piedmont Region (ARPA Piemonte), the study examined the geological, hydrogeological and hydraulic-hydrodynamic features of the aquifer, as well as the chemistry of groundwater. Furthermore, some preliminary isotopic analyses were performed. The aquifer recharge estimated through a hydrologic balance approach by Brussolo et al. (2018 - in this conference) was also taken into account. This comprehensive approach steered the definition of the aquifer system conceptual model, comprising the kind of rocks hosting groundwater and their hydraulic properties, the arrangement of groundwater flow, the seasonal evolution of groundwater quantity and the chemical quality of groundwater. Furthermore, the statistical analysis performed on datasets from monitoring stations highlighted some trends over decades. The main results can be summarized as follows: - the system consists of a multilayer that has a phreatic aquifer overlying a succession of impermeable and permeable layers, in which groundwater flow generally occurs in confined to semi-confined conditions; -the phreatic aquifer has thicknesses between 30 and 80 m and it is hosted in gravel, sandy gravel and pebbles of fluvial and fluvioglacial origin (Pleistocene-Holocene deposits). The hydraulic conductivity ranges from 5 * 10-4 m/s to 5 * 10-3 m/s; -the confined to semi-confined sub-system mainly develops within the Pliocene continental deposits, which consist of coarse-grained sands and gravels, alternating to peat-rich clayey and silty deposits. The average hydraulic conductivity of this system ranges from 4*10-5 to 4*10-4 m/s; -the aquifer system is fed by infiltration of local rainfall, river seepage and transfers of groundwater that originate in upland zones. The outputs of groundwater is for exploitation by wells and for drainage operated by rivers, in the lower part of the plain. Generally, the groundwater flow of the phreatic aquifer is separated from that of the confined to semi-confined sub-system. Nevertheless, over wide zones the shallow aquifer and the uppermost permeable layers of the deeper system result in continuity (or separated by weak thicknesses of clayey deposits), thus making possible the mixing of groundwater between the two sub-systems. The main groundwater flow paths occur from northwest to southeast and from west to east; -groundwater are mainly of the Ca(Mg)-HCO3 type with a relatively low salinity for both unconfined and confined aquifers. Nevertheless, the phreatic aquifer hosts groundwater with a relatively higher salinity and, in some zones, characterized by increasing of Cl and SO4 contents. Hence, a certain impact from anthropic activities seems to be possible. In this terms the confined to semi-confined sub-system appears effectively more protected, even though the higher salinity and Cl contents observed in a few deeper wells suggest the possibility of connection with the shallower aquifer.

In 2017 we established the first Earth Critical Zone Observatory in Italy, at the high-altitude Nivolet plain in the Gran Paradiso National Park, between about 2500 and 2700 meters asl (CZO@Nivolet). The Observatory is currently equipped with an eddy-covariance tower for CO2 and H2O fluxes; a portable accumulation chamber to measure H2O, CO2, CH4 and H2S fluxes; a double rain gauge for rainfall isotopic studies; soil moisture and hydrometric gauges. Regular samplings of the physical and chemical properties of soil as well as surface and groundwater are performed. The in-situ instruments are complemented by analyses in a suite of geochemical and isotopic laboratories at CNR IGG in Pisa and by analysis of high-resolution satellite images. While the CZO@Nivolet has multiple goals and the instrument pool is continuously upgraded, a specific question we have considered during the first year of activity is whether and how the geological setting and the geological substratum of soils affect carbon fluxes in a mountain prairie above the tree line. To this end, we have identified four plots, each having an average area of about 200 square meters, characterized by different geological substratum: (1) soil on gneiss (the dominant rock type of the Gran Paradiso massif), (2) soil on carbonate rocks, (3) soil over glacial deposits (common to most alpine areas), and (4) alluvial soil near the main stream of the Nivolet plain (Dora del Nivolet). In each plot, we performed on average 30 randomly-positioned flux measurements with the accumulation chamber method, approximately every two weeks from June to October 2017 and measuring both the sum of photosynthesis and respiration (using a transparent chamber) and pure respiration (using an opaque chamber). The preliminary results of the statistical analyses indicate that the carbonate soils behave quite differently from the other three types. A full discussion of the findings and their implications will be given.

Diplomazia2 is framed within the program "Science for Diplomacy: Multi-disciplinary Training Program", and it is the result of closer and more mature collaboration between the Directorate General for Cooperation on Development of the Ministry for Foreign Affairs and International Cooperation (MAECI), the Italian Agency for Cooperation on Development (AICS) and the National Research Council (CNR). The implementation of joint projects such as DIPLOMAzia2 highlights the effectiveness of the diplomacy-science partnership as the driving force behind the achievement of relevant goals jointly pursued by the international community.

The groundwater body hosted in the Follonica coastal plain (Grosseto, Italy) is the Italian aquifer system that was chosen for the experimentation of the FREEWAT Platform, a collection of free and open source software tools for water resource management and quantitative and qualitative modeling developed within the EU project Horizon 2020. In consideration of the studies carried out by the Institute of Geosciences and Earth Resources of the Italian National Research Council from 2006 to 2015 for the geological, hydrogeological and geochemical characterization of the 66 regional groundwater bodies (CIS), the Tuscany Region, partner of the project, has entrusted CNR-IGG for the implementation of the numerical model. A conceptual model of the aquifer system was developed by processing and combining all the geological, hydrogeological and geochemical-isotopic data. The supposed hydrostructure was tested and validated through its 3D "solid" construction, defining the geometry and the physical limits of the multi-layered aquifer system and ensuring its coherence and consistency with respect to the other geographical databases. Hydrogeological and geochemical data processing led to identify the aquifer system feeding components, the relationships between surface hydrography and groundwater and the main physical and chemical processes taking place (ion exchange, seawater ingress, etc). On this basis, the development and implementation of the flow model has started, based on the Modflow code. A focus group was organized as part of the project and stakeholders were involved with their active participation to the elaboration of the conceptual model by sharing data and other useful information. This paper describes the methodology used and the results obtained so far.

The origin of Pikrolimni water was investigated in this study, using stable isotopes, to confirm Pliny’s description that “chalastraion nitron” was produced in the basin of Lake Pikrolimni (Northern Greece). Lake Pikrolimni is located in the basin of Kilkis plain, northern Greece, formed in a shallow depression. Lake Pikrolimni is not fed by any major river, and the hydrography of the area shows that no perennial streams enter the lake directly. In the past, the major source of water to the lake was ground water. Today the dominant inflow to Lake Pikrolimni is meteoric water. The meteoric origin of the water is one of the necessary geochemical conditions that are indispensable and responsible for the formation of carbonate-bicarbonate sodium (Natron, Trona) minerals. Pikrolimni brines lie on an evaporation trend given by δD = 4.74‰ and δ18O = −13.38‰. Both isotopic values (δ18O and δD) increase with salinity, which in turn varies considerably with flooding and evaporation. In dry seasons, part of the lake is desiccated and the margins are locally covered by salts, including Na-carbonate-bicarbonate minerals, Na-sulfate and Na-chloride minerals. These minerals are submitted to repeated wetting and drying cycles under alkaline and strong evaporating conditions. This salt dissolution is reflected in Cl/Br ratios of Pikrolimni water.

Bottled waters are an increasingly significant product in the human diet. In this work, we present a dataset of stable isotope ratios for bottled waters sampled in Greece. A total of 25 domestic brands of bottled still waters, collected on the Greek market in 2009, were analysed for δ18O and δ2H. The measured stable isotope ratios range from − 9.9? to − 6.9? for δ18O and from − 67.50? to − 46.5? for δ2H. Comparison of bottled water isotope ratios with natural spring water isotope ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, showing that bottled water isotope ratios preserve information about the water sources from which they were derived and suggesting that in many cases bottled water should not be considered as an isotopically distinct component of the human diet. This investigation also helped to determine the natural origin of bottled water, and to indicate differences between the natural and production processes. The production process may influence the isotopic composition of waters. No such modification was observed for sampled waters in this study. The isotopic methods applied can be used for the authentication of bottled waters and for use in the regulatory monitoring of water products.

The volume method is used to evaluate the productive potential of unexploited and minimally exploited geothermal fields. The distribution of PCO2 in shallow groundwaters delimits the geothermal fields. This approach is substantiated by the good correspondence between zones of high CO2 flux, and the areal extension of explored geothermal systems of high enthalpy (Monte Amiata and Latera), medium enthalpy (Torre Alfina) and low enthalpy (Viterbo). Based on the data available for geothermal fields either under exploitation or investigated by long-term production tests, a specific productivity of 40 t h−1 km−3 is assumed. The total potential productivity for the recent volcanic areas of Latium is about 28 × 103 t h−1, with 75% from low-enthalpy geothermal fields, 17% from medium-enthalpy systems, and 8% from high-enthalpy reservoirs. The total extractable thermal power is estimated to be 2220-2920 MW, 49-53% from low-enthalpy geothermal fields, 28-32% from medium-enthalpy systems, and 19-20% from high-enthalpy reservoirs.

A geochemical survey on the thermal fluids released by the volcanic/geothermal system of Methana Peninsula and Loutraki area was undertaken. The Loutraki area is found in the southern part of Athens and the Methana volcano in the north-eastern part of Peloponnesus, which is characterized by high salinity waters. Chemical and isotopic contents were used for the investigation of the origin of thermal water, for the estimation of the mixing process between meteoric, magmatic and sea water involved in the deep geothermal systems and for the evaluation of the deep aquifer temperature. The chemical and isotopic data of the thermal Cl-rich water springs of Methana suggest that they are fed by thermal water mixed with local groundwater and seawater respectively. The parent hydrothermal liquid is a mixture of local groundwater (∼ 43%), seawater (∼ 34%) and arc-type magmatic water (∼ 23%). The chemical and isotopic data of the thermal HCO3-rich water springs of Loutraki samples indicate a purely meteoric origin. Assessments from chemical and isotopic geothermometer applied on the thermal waters springs suggest the probable existence of a deep geothermal reservoir of middle enthalpy (150 °C) a Methana and low enthalpy (80 °C) in Loutraki area. However, the contribution of marine solutions to the geothermal fluids of Methana and Loutraki area is one of the main cases for the disturbance of the chemical and isotopic geothermometers rendering these calculated temperatures questionable.

article i nfo The geochemical conditions that are responsible for the formation of "Chalastraion nitron" in the basin of Lake Pikrolimni (Northern Greece) were investigated in this study. The goal of the study is to confirm Pliny's description: "at Clitae in Macedonia it is found in abundance the best, called soda of Chalestra…" The ion- specific interaction model based on Pitzer's equations showed that the lake brine samples are saturated versus carbonate-bicarbonate sodium and sodium-chloride-sulfate minerals. The results of individual X- Ray Diffraction (XRD) analyses on the evaporative deposits showed that the salts consist mostly of trona, burkeite, thenardite and halite confirming Pliny's description.

Mortar that was used in building as well as in conservation and restoration works of wall paintings have been analysed isotopically (delta(13)C and delta(18)O) in order to evaluate the setting environments and secondary processes, to distinguish the structural components used and to determine the exact causes that incurred the degradation phenomena. The material undergoes weathering and decay on a large proportion of its surface and in depth, due to the infiltration of water through the structural blocks. Mineralogical analysis indicated signs of sulphation and dissolution/recrystallisation processes taking place on the material, whereas stable isotopes provided information relative to the origin of the CO(2) and water during calcite formation and degradation processes. Isotopic change of the initial delta(13)C and delta(18)O in carbonate matrix was caused by alteration of the primary source of CO(2) and H(2)O in mortar over time, particularly by recrystallisation of calcite with porewater, evaporated or re-condensed water, and CO(2) from various sources of atmospheric and biogenic origin. Human influence (surface treatment) and biological growth (e.g. fungus) are major exogenic processes which may alter delta(18)O and delta(13)C in lime mortar.

Lo sviluppo di modelli numerici dei corpi idrici sotterranei ha avuto un notevole impulso negli ultimi anni, specialmente in risposta alla necessità degli enti che si occupano della loro tutela sia in termini quantitativi sia qualitativi di avere a disposizione strumenti in grado di aiutarli nelle fasi di pianificazione, gestione e salvaguardia; parallelamente, l'esistenza di software e interfacce grafiche esclusivamente commerciali ha fatto emergere la necessità di sviluppare strumenti open-source adatti allo scopo. Il progetto EU Horizon 2020 FREEWAT, di cui Regione Toscana è partner, si propone lo sviluppo di un ambiente di modellazione GIS integrato, open source e di dominio pubblico per la simulazione di quantità e qualità delle acque superficiali e sotteranee e la sperimentazione della piattaforma così realizzata, applicata a 14 casi di studio distribuiti in Europa ed in Africa; in questo contesto, Regione Toscana ha affidato all'Istituto di Geoscienze e di Georisorse del CNR la realizzazione del modello numerico del sistema acquifero della pianura costiera di Follonica (LI). La modellistica numerica idrogeologica di flusso e di trasporto costituisce certamente un potente strumento per la gestione delle risorse idriche; tuttavia, perché sia affidabile, un modello numerico deve basarsi su un solido modello concettuale capace di integrare in un quadro omogeneo e coerente tutte le conoscenze di tipo geologico, idrogeologico e geochimico-isotopico acquisite nell'ambito dello studio del sistema acquifero. E' obiettivo di questo contributo descrivere la metodologia applicata ed i risultati sin qui ottenuti nell'ambito dello sviluppo del modello numerico del sistema acquifero della pianura di Follonica: ad oggi, è stato elaborato il modello concettuale ed è nelle sue prime fasi l'implementazione di un modello numerico di flusso basato sul codice di calcolo Modflow (USGS). Lo sviluppo del modello concettuale ha previsto una prima fase di ricostruzione dell'assetto idrostrutturale del sistema acquifero sulla base dei dati idrostratigrafici disponibili e l'esecuzione di numerose attività di campagna quali la misura dei livelli piezometrici e idrometrici e della portata dei principali corsi idrici ed il campionamento delle acque superficiali e sotterranee. Successivamente, sulla base dei dati raccolti sono state definite le varie componenti di alimentazione al sistema, i processi chimico-fisici in atto, i rapporti delle falde sotterranee con le acque superficiali, ... Il modello concettuale elaborato rappresenta il quadro conoscitivo alla base dell'implementazione del modello numerico, attualmente in fase di svolgimento, che sarà sviluppato dapprima utilizzando un'interfaccia grafica commerciale e successivamente sperimentando la piattaforma open-source FREEWAT, permettendone così una corretta valutazione.

Water geochemistry is often investigated considering a large number of variables, including major, minor and trace elements. Some of these are usually well associated due to coherent geochemical behaviour, but the effect of anthropic factors tends to increase data variability, sometimes obscuring the natural laws governing their relationships. It may thus be difficult to identify geochemical features linked to natural phenomena, as well as to separate geogenic anomalies from the anthropogenic ones, or to define background or baseline concentrations for single chemical elements. This is particularly true at regional level, where numerous phenomena may interact and mix together, forming a complex pattern not easy to interpret. The identification of background or baseline values is particularly difficult due to the compositional nature of chemical variables, so that under the Compositional Data Analysis (CoDA) theory single background or baseline values lose their meaning. However, they are fundamental references for public institutions and government policies. In this contribution a new approach is proposed, aimed at investigating the regionalised structure of the geochemical data by considering the joint behaviour of several chemical elements. The approach is based on the robust CoDA theory, so that the proportionality features of abundance data are fully taken into account, enhancing their relative multivariate behaviour, as well as the influence of outliers. An application example is presented for the groundwater compositions in Tuscany Region, a surface of about 23,000 km\(^2\), where more than 6000 wells have been sampled and analysed. The mapping of robust Mahalanobis distance was able to indicate (1) in which part of the investigated area the pressure toward anomalous behaviour was higher, (2) where the compositions nearest to the barycentre were and (3) if spatial continuity was present in limited portions of the territory.

The chemical and isotopic compositions (δDH2O, δ18OH2O, δ18OCO2, δ13CCO2, δ34S, and He/N2 and He/Ar ratios) of fumarolic gases from Nisyros, Greece, indicate that both arc-type magmatic water and local seawater feed the hydrothermal system. Isotopic composition of the deep fluid is estimated to be +4.9±0.5‰ for δ18O and −11±5‰ for δD corresponding to a magmatic water fraction of 0.7. Interpretation of the stable water isotopes was based on liquid–vapor separation conditions obtained through gas geothermometry. The H2–Ar, H2–N2, and H2–H2O geothermometers suggest reservoir temperatures of 345±15 °C, in agreement with temperatures measured in deep geothermal wells, whereas a vapor/liquid separation temperature of 260±30 °C is indicated by gas equilibria in the H2O–H2–CO2–CO–CH4 system. The largest magmatic inputs seem to occur below the Stephanos–Polybotes Micros crater, whereas the marginal fumarolic areas of Phlegeton–Polybotes Megalos craters receive a smaller contribution of magmatic gases.

Lake Albano was stratified at the time of our survey, in December 1997, in agreement with previous observations [Martini et al., Geochem. J. 28 (1994) 173–184; Cioni et al., Report for the Civil Protection Department (1995); Pedreschi, Accad. Lucch. Sci. Lett. Arti (1995) 39]. In the absence of phenomena induced by seismic activity, either local or regional, lake stratification may be perturbed by cooling of shallow waters below ∼8.5°C. Circulation is expected to homogenize lake waters and eventually to trigger gas exsolution when total gas pressure exceeds hydrostatic pressure. In December 1997, total gas pressure in lake water was very close to atmospheric pressure (0.9–1.3 bar) at all depths, possibly due to the occurrence of a recent episode of circulation and presumed gas exsolution. The state of saturation of Lake Albano waters and the similarity of the relative concentrations of Na, K, Mg, and Ca in lake waters, local groundwaters, and local volcanic rocks indicate that Na, K, Mg, and Ca concentrations in Lake Albano waters are mainly governed by incongruent dissolution of local volcanic rocks, coupled with minor calcite precipitation at shallow depths.

A geochemical survey carried out in November 1993 revealed that Lake Quilotoa was composed by a thin (,14 m) oxic epilimnion overlying a ,200 m-thick anoxic hypolimnion. Dissolved CO2 concentrations reached 1000 mg/kg in the lower stratum. Loss of CO2 from epilimnetic waters, followed by calcite precipitation and a consequent lowering in density, was the apparent cause of the stratification. The Cl, SO4 and HCO3 contents of Lake Quilotoa are intermediate between those of acid‐SO4‐Cl Crater lakes and those of neutral-HCO3 Crater lakes, indicating that Lake Quilotoa has a ‘memory’ of the inflow and absorption of HC1- and S-bearing volcanic (magmatic) gases. The Mg/Ca ratios of the lake waters are governed by dissolution of local volcanic rocks or magmas, but K/Na ratios were likely modified by precipitation of alunite, a typical mineral in acid‐SO 4‐Cl Crater lakes. The constant concentrations of several conservative chemical species from lake surface to lake bottom suggest that physical, chemical and biological processes did not have enough time, after the last overturn, to cause significant changes in the contents of these chemical species. This lapse of time might be relatively large, but it cannot be established on the basis of available data. Besides, the lake may not be close to steady state. Mixing of Lake Quilotoa waters could presently be triggered by either cooling epilimnetic waters by ,48C or providing heat to hypolimnetic waters or by seismic activity. Although Quilotoa lake contains a huge amount of dissolved CO2O,3 £ 10 11 gU; at present the risk of a dangerous limnic eruption seems to be nil even though some gas exsolution might occur if deep lake waters were brought to the surface. Carbon dioxide could build up to higher levels in deep waters than at present without any volcanic re-awakening, due to either a large inflow of relatively cool CO 2-rich gases, or possibly a long interval between overturns. Periodical geochemical surveys of Lake Quilotoa are, therefore, recommended. q 2000 Elsevier Science B.V. All rights reserved.

The accumulation chamber methodology allows one to obtain reliable values of the soil CO2 flux, ϕsoil CO2, in the range 0.2 to over 10 000 g m−2 d−1, as proven by both laboratory tests and field surveys in geothermal and volcanic areas. A strong negative correlation is observed between Δϕsoil CO2/Δt and ΔPatm/Δt. Maps of classes of log ϕsoil CO2 for the northern sector of Vulcano Island, Solfatara of Pozzuoli, Nea Kameni Islet and Yanbajain geothermal field evidence that active faults and fractures act as uprising channels of deep, CO2-rich geothermal or magmatic gases. The total diffuse CO2 output was evaluated for each surveyed area.

In questo lavoro vengono presentate le varie fasi di attività svolte da un gruppo di lavoro costituito da ricercatori delle tre università regionali (Firenze, Pisa e Siena), del CNR di Pisa (Istituto di Geoscienze e Georisorse), dell'ARPAT, del Consorzio LAMMA e del Sistema Informativo Territoriale ed Ambientale della Regione Toscana, che hanno condotto alla costruzione del Database Geochimico regionale. Tale banca dati si propone come strumento fruibile ed accessibile a differenti livelli di utenza, i cui contenuti possano essere liberamente interrogabili e scaricabili oltre che implementabili nel tempo, secondo regole e standard condivisi. L'obiettivo è quello di fornire un importante riferimento conoscitivo nel campo delle informazioni geochimiche relative alle varie matrici geoambientali nel territorio toscano. Nella prima fase di progetto le attività sono state orientate non solo a favorire la piena fruizione di dati disaggregati già disponibili tramite una potente interfaccia webgis, ma anche ad individuare l'utilizzo di strumenti grafici e numerici di analisi statistica mediante i quali: 1) comprendere la variabilità del fenomeno oggetto di studio nella sua caratterizzazione spaziale; 2) individuare la posizione geografica di valori anomali; 3) confrontare gli esiti di diverse metodologie analitiche sperimentali per uno stesso elemento e/o specie chimica; 4) estrarre dati relativi ad un determinato periodo temporale e/o una determinata area e 5) verificare l'impatto della presenza di informazione numerica con valore inferiore al limite di rilevabilità strumentale. Ulteriori sviluppi del progetto dovranno prevedere la definizione di regole e strumenti finalizzati ad una continua e progressiva implementazione controllata del Database, anche in previsione di un utilizzo di nuove informazioni provenienti da soggetti esterni al gruppo di lavoro.

Water demand for urban, industrial, and agricultural purposes is a major concern in developed and third world countries. A careful evaluation for an appropriate and sustainable use of water resources is a priority. Geochemical processes can lead to measurable variations of the aquatic environment, which can be studied through the analysis of the dissolved solutes. Even if this review is not meant to be exhaustive, it is intended to give a view on the importance of environmental isotopes in the context of groundwater quality assessments. This is done by briefly recalling some basic notions for each described system, followed by relevant applications and reports about some significant case studies. This review includes well-established isotopic systematics, such as those of O and H in water, C in dissolved inorganic carbon (DIC), S and O in sulfates, and N and O in nitrates and those of boron and Sr, which in the last lustrums have found large application in the field of water geochemistry. This chapter ends with some examples related to nontraditional isotopes, i.e., Fe, Cr, and Cu, in order to highlight the potential of the environmental isotopes to trace sources, fate, and behavior of different solutes and metals in surface water and groundwater.