Search results for "Aquifer"
showing 10 items of 103 documents
Sensitivity Analysis Of Multi-Electrode Arrays For Characterizing The Non-Saturated Zone In Groundwater Vulnerability Assessment
2009
The near-surface environment acts as a filter and buffer for contaminants introduced from the surface by anthropogenic activities. For this reason there is a great need to improve our understanding of the shallow subsurface taking into account the increasing demand for vulnerability maps which illustrates the exposure of aquifers against pollution. These maps are designed to show areas of greatest potential for groundwater contamination on the basis of local subsurface conditions. A shallow, unconfined sand-and-gravel aquifer is highly vulnerable to pollutants because rapid recharge gives little time to contaminants to degrade naturally or be adsorbed before reaching the aquifer. Conversely…
Hydrogeochemical changes during managed aquifer recharge (MAR) in a salinised coastal aquifer
2021
15 p. - Supplementary data to this article can be found online at https://doi.org/10.1016/j.apgeochem.2020.104866. - The data used to support the findings of this study are available from http://repositori.uji.es/xmlui/handle/10803/620641.
Mercury concentration, speciation and budget in volcanic aquifers: Italy and Guadeloupe (Lesser Antilles)
2009
Abstract Quantifying the contribution of volcanism to global mercury (Hg) emissions is important to understand the pathways and the mechanisms of Hg cycling through the Earth's geochemical reservoirs and to assess its environmental impacts. While previous studies have suggested that degassing volcanoes might contribute importantly to the atmospheric budget of mercury, little is known about the amount and behaviour of Hg in volcanic aquifers. Here we report on detailed investigations of both the content and the speciation of mercury in aquifers of active volcanoes in Italy and Guadeloupe Island (Lesser Antilles). In the studied groundwaters, total Hg (THg) concentrations range from 10 to 500…
Competitive versus efficient extraction of a common property resource: The groundwater case
2001
Abstract In this paper socially optimal and private extraction of a common property aquifer are compared. Open-loop equilibrium and feedback equilibrium in linear strategies have been computed to characterize private extraction. The use of these two equilibrium concepts allows us to distinguish between cost and strategic externalities as long as the open-loop solution captures only the cost externality, and the feedback solution captures both. The results show that strategic behaviour increases the overexploitation of the aquifer compared to the open-loop solution. However, if the groundwater storage capacity is large, the difference between the socially optimal and private extraction, the …
Dissolution Process: When Does the Process Start
2019
Dissolution process is a complex phenomenon controlled by several factors as like lithology, porosity, stress orientation, environmental conditions and networks of fractures. Then, fault zone and fractures play an important role in fluid circulation and in dissolution, acting as barriers or conduits. In fact, the fault zone has a high permeability only in the early stages of the movement, but shortly the process of recrystallization and reprecipitation reduces the permeability greatly within them. Despite this, traditionally (Cucchi and Forti in In Att. e Mem. Comm. Grotte “E: Boegan” 87–93, 1988; Bini et al. in Varese Lake and the Quaternary 6:3–14, 1993; Ferrarese and Meneghel in Aspetti …
Preliminary geochemical characterization of the Mts. Simbruini karst aquifer (Central Italy)
2021
Mts. Simbruini karst aquifer feeds important springs whose capture contributes to the water supply of Rome City. To improve the geochemical characterization of this aquifer, we analyzed 36 groundwater samples, 29 from springs and 7 from shallow wells, collected in 1996 and 2019. Atomic adsorption spectroscopy, tritration, ionic chromatography and mass spectrometry were the used analytical methods. Ground waters are bicarbonate alkaline-earth type and HCO3 dominance confirms that the aquifer is hosted in carbonate rocks. Total alkalinity vs. cations plot indicates that CO2 driven weathering controls the water chemistry. The probability plots of HCO3, cations and Ca2+ +Mg2+ indicate four grou…
Application of Geostatistical Tools to the Geochemical Characterization of the Peloritani Mts (Sicily, Italy) Aquifers
2021
Sources of groundwater contaminants in inhabited areas, located in complex geo-tectonic contexts, are often deeply interlocked, thus, making the discrimination between anthropic and natural origins difficult. In this study, we investigate the Peloritani Mountain aquifers (Sicily, Italy), using the combination of probability plots with concentration contour maps to retrieve an overall view of the groundwater geo-chemistry with a special focus on the flux of heavy metals. In particular, we present a methodology for integrating spatial data with very different levels of precision, acquired before and during the “geomatic era”. Our results depict a complex geochemical layout driven by a geo-puz…
Geochemical characterization of surface waters and groundwater resources in the Managua area (Nicaragua, Central America)
2008
This paper reports new geochemical data on dissolved major and minor constituents in surface waters and ground waters collected in the Managua region (Nicaragua), and provides a preliminary characterization of the hydrogeochemical processes governing the natural water evolution in this area. The peculiar geological features of the study site, an active tectonic region (Nicaragua Depression) characterized by active volcanism and thermalism, combined with significant anthropogenic pressure, contribute to a complex evolution of water chemistry, which results from the simultaneous action of several geochemical processes such as evaporation, rock leaching, mixing with saline brines of natural or…
Geochemistry and potential use of groundwater in the Rocca Busambra area (Sicily, Italy)
2008
In the Rocca Busambra area (mid-west Sicily, Italy), from November 1999 to July 2002, 23 water points including wells and springs were sampled and studied for their chemical and isotopic compositions. Two rain gauges were also installed at different altitudes, and rainwater was collected monthly to determine the isotopic composition. The obtained results revealed the Rocca Busambra carbonate complex as being the main recharge area on account of its high permeability value. From a chemical view point, two main groups of water can be distinguished: calcium–magnesium–bicarbonate-type and calcium–magnesium–chloride–sulphate-type waters. The first group reflects the dissolution of the carbonate …
Targeted delivery of hydrogen for the bioremediation of aquifers contaminated by dissolved chlorinated compounds.
2019
Dihydrogen (H2) gas injection is a promising option to enhance the reductive biodehalogenation of contaminants in groundwater. However, it is challenging to ensure its targeted delivery at the right places in plumes, and for the long times required for bioremediation. In this paper, the ability of surfactant foam to retain H2 in the saturated zone and to enhance its release in the dissolved form was compared to traditional biosparging. H2 gas was injected, either alone, or as foam, in a 2D saturated cell packed with glass beads. This cell was continuously flushed with deoxygenated water to mimic aquifer circulation, and H2 was studied both in terms of gas distribution in the cell and dissol…