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Über dieses Buch

This book focuses on scientific and technological aspects of groundwater-resources assessment and surveillance. It describes relevant risks and investigates selected techniques for the monitoring and mitigation of the individuated threats to groundwater quality. The authors discuss the concepts of groundwater-resources protection and offer examples of both geogenic and anthropogenic degradation of groundwater quality, such as heavy metals from mining activities and natural water-rock interactions, as well as risk of contamination due to geological CO2 storage practices etc. The volume also covers non-invasive monitoring techniques and briefly addresses innovative sensor technologies for the online assessment of water quality. Furthermore, the role played by geochemical techniques, the potential of environmental isotopes and the support provided by physical modelling are highlighted. The chapters guide the reader through various viewpoints, according to the diverse disciplines involved, without aiming to be exhaustive, but instead picking representative topics for their relevance in the context of groundwater protection and control.
This book will be of interest to advanced students, researchers, policy-makers and stakeholders at various levels.

Inhaltsverzeichnis

Frontmatter

Introduction

Abstract
Groundwater is the only source of water supply for some countries in the world and the main source for many other countries. Especially in the European Union and in the United States of America, the role of high-quality groundwater is fundamental for the drinking water supply, and this is true also for some countries in Asia, Africa and Australia. Thus, in a growing number of contexts, safeguarding drinking water supplies is strictly linked with the protection of local groundwater resources. The usage of groundwater for irrigation has also a relevant share in many countries, sometimes contributing to stress the resource. The assessment of groundwater vulnerability and the individuation of potential hazards are thus becoming common and often compelling issues. Given this particular background, this introductory chapter illustrates the motivational framework of this book and outlines its contents.
Andrea Scozzari, Elissavet Dotsika

Protection of Groundwater Resources: Worldwide Regulations and Scientific Approaches

Abstract
The increasing role of groundwater in municipal water networks in many countries of the world makes the protection of groundwater resources an essential practice for safeguarding drinking water supplies. Several scientific-technical approaches are adopted worldwide to face this issue. In addition, some countries mainly depend on groundwater also for non-domestic use, making this topic even more critical. This chapter provides an overview of the main directives and their related technical aspects, concerning the protection zones of groundwater sources for human consumption. The main results of a multidisciplinary study are also presented, highlighting how the knowledge of physical and chemical aspects of groundwater bodies is a fundamental tool for protecting this vital resource and assuring its availability for the future generations.
Marco Doveri, Matia Menichini, Andrea Scozzari

Threats to the Quality of Water Resources by Geological CO2 Storage: Hydrogeochemical and Other Methods of Investigation: A Review

Abstract
In the last decades, geological storage of CO2 is under discussion, in order to reduce emissions of greenhouse gases to the atmosphere, as a contribution to the mitigation of climate change. Deep saline aquifers in sedimentary basins are being considered as the most prominent locations for CO2 storage and sequestration. This chapter provides an overview of recent research regarding CO2 storage with focus on hydrogeochemical methods of investigation, gas–water–rock interactions and monitoring methods as well as potential risks to freshwater resources. The main trapping mechanisms for CO2 in deep geological formations are: (1) hydrodynamic trapping as a supercritical fluid below the caprock, (2) residual trapping within the pores of reservoir rocks, (3) solution trapping as aqueous species dissolved in formation water, and (4) mineral trapping by precipitation of carbonate minerals. However, risks for freshwater resources can arise due to low pH values. As a consequence, the dissolution of minerals is causing high concentrations in trace elements that are potentially dangerous for human health. Another aspect is ascendant saline water which could intrude into shallower fresh water aquifers due to the displacement caused by injection pressure. Hydrogeochemical monitoring methods are recommended to detect possible CO2 leakage.
L. Thomas, M. Schneider, A. Winkler

Groundwater Contamination: Environmental Issues and Case Studies in Sardinia (Italy)

Abstract
In this study, the arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn) contamination has been evaluated in the groundwater of Sardinia (Italy). Contamination by such chemical species is among the most relevant risks for many populations, thus giving general interest to the case studies presented in this chapter. A brief introduction about the European legislative framework is given, followed by a description of the analytical methods used and a discussion of the results. Two areas were selected as case studies: the Osilo area, devoted to geogenic degradation, and the Iglesiente–Fluminese mining district mainly affected by anthropogenic contamination. The geochemical controls on the natural baselines of As, Cd, Pb, and Zn are generally related to natural sources, mostly derived from water–rock interaction processes in areas of known mineral occurrences. In fact, median concentrations of the investigated elements in the mineralized areas are much higher than those of the corresponding median regional values and sometimes exceed the Italian limits for drinking water. In the Iglesiente–Fluminese mining district very high concentrations of Cd, Pb, and Zn were measured in groundwater that circulates in areas affected by past mining activities.
The results of this study clearly show that the understanding of the trace metal pollution trends, and the distinction of the anthropogenic impacts on the aquifer systems, is essential for evaluating the natural baseline of contaminants as well as for distinguishing the relevant processes that influence their chemical characteristics. Such information, together with the geological features of a region and/or subregion, should be taken into account prior to defining regulatory limits of contaminants in groundwater.
Riccardo Biddau, Rosa Cidu

Geological Sources of As in the Environment of Greece: A Review

Abstract
This review summarizes the existing data about the geological sources of As in Greece; their variety and the relevant concentrations make Greece a peculiar territory to generalize and better understand the methodology for their assessment. These sources concern As-containing ores in active and abandoned mining areas, geothermal/hydrothermal waters, lignites in exploited and unexploited deposits, As-minerals in various rock types such as metamorphic rocks, and mineral dust originating in Sahara desert. It is considered that As release from the above sources, in conjunction with various anthropogenic As fluxes, occasionally creates distinct areas with contaminated groundwater, soils, marine and atmospheric environment. In general, Greece has been reported as a global As “hot spot” and it is argued that a significant amount of the Hellenic population might be affected by As pollution. The most important and permanent As source seems to be geothermal/hydrothermal fluids, due to faults and volcanic activity, affecting the underground, surface, and marine aquatic environment.
Graphical Abstract
Platon Gamaletsos, Athanasios Godelitsas, Elissavet Dotsika, Evangelos Tzamos, Jörg Göttlicher, Anestis Filippidis

Groundwater Contamination Studies by Environmental Isotopes: A review

Abstract
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.
Barbara Nisi, Brunella Raco, Elissavet Dotsika

The Importance of Reduced-Scale Experiments for the Characterization of Porous Media

Abstract
In order to reduce threats to the quality of groundwater resources, prevention and control are the most important activities to carry out. In general, these activities require the ability to model the flow and solute transport phenomena in the aquifer. Thus, it is essential to collect information about potential contamination sources, boundary conditions, hydrological forcing, and the magnitudes and spatial distributions of the hydrodynamic and hydrodispersive parameters of the porous media. Measurements of such parameters, available only at a finite number of locations, are often obtained by means of different techniques and can be representative of various measurement scales.
The use of available data, necessarily distributed on different scales, for characterizing porous media at a defined scale is a key question of great interest. With the aim to investigate on the hydraulic conductivity scale effect on a homogeneous porous medium, several experiments were carried out at the Hydrogeosite Laboratory (Marsico Nuovo, Italy). This laboratory is a large scale model sized 10 × 7 × 3 m3, filled with a homogeneous medium made up of quartz-rich sand. The results are described by separating the two important scale-ambits under consideration, obtaining two scale power laws. Moreover, the scale effect of the hydraulic conductivity has been detected by considering the water flow type (uniform or radial) into the porous medium. However, the results, either considering the only scale law or multi-scale laws, confirm what was proved by several authors for heterogeneous porous media, that is the trend of hydraulic conductivity to reach a higher limit when the measurement scale increases and, in our opinion, regardless of the heterogeneity of the porous medium. Finally, a hydrogeophysical approach is described in this chapter, in order to show how a passive geophysical method as self-potential can estimate the hydraulic conductivity. It is an important step when large site should be characterized and few direct borehole data are available. These aspects are important because the hydraulic conductivity estimation is the first step for the characterization of a site.
S. Straface, E. Rizzo

Mathematical Models as Tools for Prevention and Risk Estimates of Groundwater Pollution: Contributions and Challenges

Abstract
In many parts of the world, groundwater is the only resource available to meet the vital needs of the population, especially in dry areas. The availability and quality of such resources are highly threatened now by climate change and numerous pollution factors.
Numerical models of flow and transport in saturated porous media are of major significance in the realization of simulations of management scenarios and in the evaluation of potential risks of pollution. The main constraint to the development and implementation of these models is the quantification of the parameters of flow and transport phenomena. In fact, these parameters fully control the results of the simulations. To overcome these limitations, field experiments are essential in order to minimize the errors associated with the results of these simulations.
This chapter presents some applications on different Moroccan sites, which are vulnerable to pollution, allowing the risk assessment related with the threats to the local groundwater resources and showing the major role of these tools for the preservation of the quality of groundwater resources.
Bouabid El Mansouri, Malika Kili, Jamal Chao, Ahmed Fekri, Abdelaziz Mridekh

Groundwater Monitoring and Control by Using Electromagnetic Sensing Techniques

Abstract
Groundwater resources, which are exposed to overexploitation and pollution at regional and local levels, may take benefit from fast, nonintrusive, and inexpensive monitoring methods based on electromagnetic techniques. In fact, the available technologies can help to improve management and protection of the aquifers. This chapter deals with the role of electromagnetic sensing techniques in water monitoring with a specific focus to pollution surveys in groundwater bodies. Being sensitive to the presence of water in the subsoil and its electrical conductivity, which in turn depends on the ionic content, the electromagnetic sensing techniques are useful tools for groundwater identification and soil quality assessment. In fact, these sensing techniques offer advantages such as quickness, nonintrusivity, and the possibility of investigating large areas at reasonable costs. However, the appropriate use of these techniques implies an adequate knowledge of their working principles as well as of their on field application procedures, which mainly depend on the survey aim and the geological and logistic conditions of the site. This chapter also discusses the uncertainty in the interpretation of results, which is due to the fact that the electromagnetic sensing techniques are based on indirect inspections. Several strategies can be exploited to reduce ambiguity of results, such as the integration of different electromagnetic techniques and the comparison between field data and those provided by laboratory experiments. These issues are herein addressed through practical examples concerning two study cases, one referred to a site located in Serbia-Herzegovina and one located in Italy. In particular, we illustrate the physical concepts, the operative aspects, the data processing, and the integration of results concerning the following measurement techniques: electrical resistivity tomography (ERT), ground-penetrating radar (GPR), time-domain-induced polarization (time domain IP), and self-potential method (SP). The two study cases concerns an industrial site and a large waste dump structure. These sites represent specific examples of soil monitoring and have been selected in order to evaluate the performance of the proposed techniques. For each site, we provide a description of the survey results accounting for geological evidences, logistic constraints, and physical limitation of the used techniques. Finally, we highlight the advantages offered by a cooperative use of different techniques and suggest strategies to overcome intrinsic limitations of each one of the considered survey methods.
M. Bavusi, V. Lapenna, A. Loperte, E. Gueguen, G. De Martino, I. Adurno, I. Catapano, F. Soldovieri

Pollution Detection by Electromagnetic Induction and Electrical Resistivity Methods: An Introductory Note with Case Studies

Abstract
This chapter introduces the combined usage of electromagnetic induction and electrical resistivity methods for the assessment of soil pollution at shallow depths, with a particular focus on situations of potential contamination of groundwater. After a brief introduction of the electrical resistivity tomography (ERT) and the electromagnetic induction (EMI) techniques, three case studies are presented, dealing with potential threats to groundwater resources, in which the synergic usage of ERT and EMI permitted effective investigations about the contamination status and possible threats.
Yuri Manstein, Andrea Scozzari

The Combination of Geoelectrical Measurements and Hydro-Geochemical Studies for the Evaluation of Groundwater Pollution in Mining Tailings Areas

Abstract
Sulfide-bearing mill wastes of the Salair Ore Processing Plant situated in the Kemerovo region (Russia) were investigated in the time period 1999–2011. Multipurpose studies of the Talmovskie mining tailings allowed the determination of the composition of the wastes, the acid mine drainages, and the affected groundwater. Geophysical sounding techniques (frequency sounding and electrical tomography) were used to trace the geoelectric zoning of the wastes, expressed as a consistent change of the electrical resistivity specific electrical resistance (SER) from zone to zone. Layers with low resistivity indicate areas with pore spaces filled by highly mineralized solutions. These layers extend to depths of 4–5 m, indicating the penetration of toxicants into the groundwater horizon. The pollution of groundwater was confirmed by chemical analysis, according to which the concentrations of Zn, Pb, and Cd in water samples from the wells are two to three orders of magnitude higher than the maximum permissible concentration (MPC). The authors provide an attempt to identify the correlation and quantitative relationships between SER and the total amount of various metal species present in the wastes and water extracts. The proposed approach permitted to estimate the amount of accumulated tailings, in order to predict changes in the total concentrations of Mn, Al, Fe, Cu, Zn, Cd, and Pb in waste and water extracts to a depth of 30 m.
Svetlana Bortnikova, Nataliya Yurkevich, Elisaveta Bessonova, Yury Karin, Olga Saeva

Microfluidic Optical Methods: A Review

Abstract
This chapter reviews the state-of-the-art microfluidic optical methods for water monitoring and analysis. Microfluidics permits to reduce the system dimension, increasing its analytical speed and sensitivity. It also permits to achieve an unprecedented economy of scale, by dramatically increasing production throughput and reducing individual costs. The different linear optical phenomena (e.g., refractive index variations, absorption) and non-linear phenomena (e.g., fluorescence, phosphorescence, Raman scattering) are analysed and discussed in this chapter; in fact, the choice of a particular optical method depends on the analyte and the sensitivity required. Authors show that the strong integration between optics and microfluidics permits to reduce the measurement time, the cost and the portability of the sensing system, opening unprecedented possibilities in the context of water quality monitoring.
Genni Testa, Gianluca Persichetti, Romeo Bernini

Non-conventional Electrochemical and Optical Sensor Systems

Abstract
Electroanalytical methods are a common tool for the assessment of chemical peculiarities of aqueous solutions. Also, the analysis of water based on optical sensors is a mature field of research, which already led to industrial applications and standard laboratory practices. Nevertheless, scientific literature is still offering new sensor techniques and innovative measurement approaches in both fields. In particular, for fast characterisation of liquids and change detection applications in a continuous monitoring context, the technology of taste sensors based on electrochemical techniques is still witnessing a growing interest. Such devices are often defined as “electronic tongues” or “e-tongues”. In addition, emerging inexpensive and portable devices with optical-sensing capabilities can be used for monitoring applications with a novel approach. This chapter gives an overview of recent techniques developed in both fields and presents several potential applications and case studies that deal with the context of water quality assessment. A brief introduction about the basics of each measurement technology, even if not exhaustive, is also provided.
Corrado Di Natale, Francesca Dini, Andrea Scozzari

Backmatter

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