1,721,022 research outputs found
Le massif du Gran Sasso. Abruzze, Italie centrale Synthèse hydrogéologique, par m. Petitta & M. Tallini, 2002
No full textNicod Jean. Le massif du Gran Sasso. Abruzze, Italie centrale Synthèse hydrogéologique, par m. Petitta & M. Tallini, 2002. In: Karstologia : revue de karstologie et de spéléologie physique, n°42, 2e semestre 2003. Les cavités glaciaires sous le regard des spéléologues. pp. 55-56
Le massif du Gran Sasso. Abruzze, Italie centrale Synthèse hydrogéologique, par m. Petitta & M. Tallini, 2002
No full textNicod Jean. Le massif du Gran Sasso. Abruzze, Italie centrale Synthèse hydrogéologique, par m. Petitta & M. Tallini, 2002. In: Karstologia : revue de karstologie et de spéléologie physique, n°42, 2e semestre 2003. Les cavités glaciaires sous le regard des spéléologues. pp. 55-56
Innovative methodology for quantitative and qualitative assessment of water resources in karst aquifers: a case study in southern Lazio region, central Italy
Full text linkThis paper outlines the results of a hydrogeological study carried on from July 2014 to November 2106 to assess quantitatively and qualitatively water resources (groundwater and surface water) emerging in the Upper Valley of the Aniene River (Latium Region, Central Italy). This work deals with the Environmental Monitoring Plan, related to the catchment project of the Pertuso Spring, which is going to be exploited to supply an important water network in the South part of Roma district. The study area is located in the Upper Valley of the Aniene River, in the outcrop of Triassic-Cenozoic carbonate rocks, and belong to an important karst aquifer. Pertuso Spring is the main outlet of this karst aquifer and is the one of the most important water resource in the southeast part of Latium Region, used for drinking, agriculture and hydroelectric supplies. This hydrogeological system is characterized by a strong local hydraulic connectivity between the Aniene River surface water and groundwater coming from the Pertuso Spring.
First at all, in this study, in order to estimate the vulnerability degree of the karst aquifer feeding the Pertuso Spring, the COP method has been applied and vulnerability maps are proposed. Thus, with the aim of highlighting the karst features key-role in the unsaturated zone, a new vulnerability approach has been set up, starting from two discretization approaches. The aim of this work is to compare both results of the intrinsic vulnerability mapping, in order to evaluate which one is the most suitable for the study area.
On the basis of the hydrogeochemical data and their interpretations for groundwater and surface water, monitored from July 2014 to November 2016, a hydrogeological study has been carried on to identify flowpaths and hydrogeochemical processes governing groundwater-surface water interactions in this region. To this end, discharge surveys were carried out on four monitoring sections along the Aniene River. The proposed conceptual model shows that the karst aquifer feeding the Pertuso Spring supplies the Aniene River, highlighting seasonal variability depending on the rainfall regime.
The analysis of solute contents in the monitoring points has suggested the identification of the Magnesium ion as a conservative tracer in this specific system and, consequently, to the development an indirect method for the evaluation of karst spring discharge based on discharge measurements and water geochemical data. This method is based on the elaboration of surface water discharge measurements in relationship with Mg2+ concentration values, determined as for groundwater, coming from the Pertuso Spring, as for surface water samples, collected upstream and downstream the spring, along the Aniene River streamflow. This method has been validated by the comparison with discharge values obtained using the current meter method and by geochemical data.
This study suggests that the application of the Magnesium ion as an environmental tracer may provide a means to evaluate discharge of the Pertuso Spring, as it came up to be a marker of the mixing of surface water and groundwater. On the other hand, the Magnesium ion concentration provides information for the identification of groundwater flow systems and the main hydrogeochemical processes affecting the composition of water within the karst aquifer feeding the Pertuso Spring
Arsenic speciation in a contaminated coastal aquifer below a former fertilizer production plant
No full textInorganic arsenic has been widely used during
the production cycle of fertilizers and pesticides
and leakage into sub-soils and shallow
groundwater has been reported in the recent
literature (Root et al. 2009; Cancés et al. 2005).
Despite of this, most of the scientific papers has
been focused on natural arsenic mobilization
and geochemical cycling in the subsurface
(Hering J. G. and Kneebone 2002; Lin and Puls
2003). Thus, more studies are still needed to
understand the mobilization/immobilization
mechanisms of arsenic in highly contaminated
sites. Since the arsenic mobilization is usually
driven by redox processes, pH changes and
ionic strength of the solutions (Smedley and
Kinniburgh 2002), it is foremost important to
study its behavior in coastal aquifers where all of
these factors essentially coincide. In fact, like for
the surface waters, the groundwater mixing zone
can affect the biogeochemical cycling of metals
and nutrients, which are sensitive to changes in
salinity and redox potential (Slomp et al. 2004).
The study site is a former fertilizer plant located
near the shore line, in Italy. The overall
groundwater geochemistry at the study site has
been documented in a previous paper
(Mastrocicco et al. 2011). Within this framework,
a detailed characterization of arsenic in
groundwater was performed to elucidate the
mobilization/immobilization mechanisms actually
occurring at the site
Density dependent transport modelling of Total Chlorinated Hydrocarbons to evaluate the remediation strategy in a Megasite
No full textThe calibrated tridimensional flow and transport model was a useful tool to assess the efficacy of the remediation strategy employed: the model showed that TCH were confined within the Megasite boundaries despite the presence of scattered residual DNAPL source zones. The shape of TCH plumes was primarily influenced by the saltwater wedge location, with the highest TCH concentrations located in the upper part of the aquifer near the shore line. To further improve TCH recovery and mitigate saltwater intrusion, shallow wells might be employed near the sea boundary
Coastal aquifer contamination by arsenic and phosphorous from a fertilizer production plant
No full textInorganic arsenic has been widely used during the production cycle of fertilizers and pesticides and leakage into subsoils
and shallow groundwater has been reported in the recent literature. Despite of this, most of the scientific papers
have focused on natural arsenic mobilization and geochemical cycling in the subsurface. Since the arsenic mobilization
is usually driven by redox processes, pH changes and ionic strength of the water, it is of foremost importance to study its
behavior in coastal aquifers where all of these factors essentially coincide. The study site is a former fertilizer plant
located near the shore line in Italy, where a pump and treat remediation scheme has been active since 2001. A detailed
characterization of arsenic in groundwater was performed to elucidate the mobilization/immobilization mechanisms
actually occurring at the site. It was found that most of the arsenic was entrapped in the sediments located near to the
source zone, while phosphorous (mainly phosphate) migrated further downstream.
A marked vertical reverse trend of EC and Eh was found within the aquifer: the elevated EC was due to the seawater
wedge intrusion enhanced by pumping wells, while anoxic conditions were due to organic matter oxidation by sulphate
provided by seawater. The arsenic speciation in groundwater showed the net predominance of As(III) except in the upper
portion of the aquifer, where post-oxic condition occurred due to continuous oxygen exchange with the vadose zone. In
the deeper portion of the aquifer the As(III) concentrations increased up to 900 μg/l, while As(V) remained stable. This
feature was probably due to the elevated ionic strength of deep groundwater, which can displace weakly bonded oxianions
from exchange sites and also by reducing conditions which promoted As(III) mobilization. Phosphate was
present almost only in groundwater due to the reducing conditions of the aquifer.
This characterization confirmed that two different mechanisms for arsenic fate were active: (i) the oxidation and
consequent sequestration in the upper oxidized zone, near the water table, with a marked decrease of total arsenic in
groundwater with respect to the aquifer bottom, where (ii) the reduced and salinized conditions gave rise to very high
arsenic concentrations with As(III) as the main groundwater species
Intrinsic vulnerability uncertainties due to climatic variability and soil permeability in the Fucino plain (IT)
No full textReactive nitrogen losses from agricultural activities are a global problem and its management requires an integrated interdisciplinary approach. Throughout the world, alluvial plains are usually the most impacted regions by nitrate pollution and especially by nitrate groundwater contamination. This study shows that climatic variability in this small alluvial plain affects LOS indices results less than ks uncertainties. The application of LOS indices showed its aptitude to adequately represent the intrinsic vulnerability to nitrogen and water losses in agricultural alluvial plains
Bias between flowmeter measurements and numerical model in a contaminated coastal aquifer
No full textDuring the characterization of the subsurface
fluxes, the use of different techniques
(geophysical, hydrological, hydrochemical)
usually help to understand the processes taking
place within the aquifer (Schürch & Buckley
2002). Generally, low-permeability, non-reactive,
horizontal flow barriers (HFBs) are used to
contain contaminants in aquifer and prevent
further spreading of contaminants in
groundwater. Grout curtains HFBs, which are the
focus of this study, are supposed to be
impermeable. Barriers are typically used in
conjunction with interior and exterior extraction
wells to help maximize containment inside the
barrier and capture leakage outside the barrier
(U.S. Environmental Protection Agency, 1996)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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