Groundwater Level Prediction/Forecasting and Assessment of Uncertainty Using SGS and ARIMA Models: A Case Study in the Bauru Aquifer System (Brazil)     

Takafuji  Eduardo Henrique de Moraes  Rocha  Marcelo Monteiro da  Manzione  Rodrigo Lilla 《Natural Resources Research》2019,28(2):487-503

Natural Resources Research - Best water management practices should involve the prediction of the availability of groundwater resources. To predict/forecast and consequently manage these water...  相似文献   

Hazards threatening underground transport systems     

Forero-Ortiz  Edwar  Martínez-Gomariz  Eduardo 《Natural Hazards》2020,100(3):1243-1261

Natural Hazards - Metro systems perform a significant function for millions of ridership worldwide as urban passengers rely on a secure, reliable, and accessible underground transportation way for...  相似文献   

Determination of Te,As, Bi,Sb and Se (TABS) in Geological Reference Materials and GeoPT Proficiency Test Materials by Hydride Generation‐Atomic Fluorescence Spectrometry (HG‐AFS)     

Eduardo Teixeira Mansur  Sarah‐Jane Barnes  Dany Savard  Peter C. Webb 《Geostandards and Geoanalytical Research》2020,44(1):147-167

The study of Te, As, Bi, Sb and Se (TABS) has increased over the past years due to their use in the development of low‐carbon energy technologies. However, there is a scarcity of mass fraction values of TABS in geological reference materials. This underlines the difficulty in undertaking routine determinations of these elements. The mass fractions of TABS were determined in geological reference materials using hydride generation‐atomic fluorescence spectrometry (HG‐AFS), calibrated with standard solutions. Comparisons with literature values were used to validate the method. Samples from the GeoPT proficiency test were also analysed. For most elements, there are no assigned or even provisional values for many of the GeoPT and reference materials because of the wide range of results reported. For mass fractions above the quantification limit of the method, our results are in good agreement with the median of GeoPT results. Thus, we propose GeoPT median values as informational values for these elements. In contrast, at mass fractions < 0.5 µg g^?1 median values of Se from GeoPT are systematically higher than our results. Our Se results are in agreement with the reference materials down to 0.02 µg g^?1, which suggest that many of the results for Se reported in GeoPT testing are too high.  相似文献   

The barnacle Balanus amphitrite as a bioindicator for Cd: Development and application of a simulation model     

Eduardo Teixeira da Silva  David Klumpp  Michael Ridd 《Estuarine, Coastal and Shelf Science》2009

The efficacy of the barnacle Balanus amphitrite as a bioindicator for Cd in the environment was investigated through simulation exercises in an ecotoxicological simulation model based on field data. The study showed in general that B. amphitrite is a good bioindicator to record mean trends of the Cd bioavailability in the environment. The model correct reflected differences between high and low patterns of Cd concentrations in the barnacle in the field, but it did not accurately reflect short-term temporal variations. A model investigation pointed out three issues that must be taken into account when using B. amphitrite as bioindicator for Cd bioavailability in the environment: (1) variations in the mean weight of the sampled population may affect the barnacle's Cd concentration determination, specially if a size effect for the metal concentration in the organism is not detected; (2) a sampling effort approximately 5 times greater than that of usually applied in such studies would be required to detect an environmental change that caused a realistic increase in the main source of Cd to the barnacle; and (3) barnacle tissue better responds to long-term changes in the Cd level of its sources.  相似文献   

Spatial and temporal distribution of cadmium and copper in water and zooplankton in the Bahía Blanca estuary,Argentina     

Melisa Daiana Fernández Severini  Sandra Elizabeth BottéMónica Susana Hoffmeyer  Jorge Eduardo Marcovecchio 《Estuarine, Coastal and Shelf Science》2009

Cadmium and copper in the dissolved and particulate phase and in zooplankton were determined in the Bahía Blanca estuary during six surveys from March to December 2005. Temperature, pH, salinity, dissolved oxygen, suspended particulate matter, particulate organic matter and chlorophyll-a were also considered. Dissolved Cd was below the detection limit (0.2 μg L⁻¹) for almost the entire study period whereas Cu concentrations (0.5–2.4 μg L⁻¹) indicated a continuous dissolved Cu input. Particulate Cd concentrations ranged from below the detection limit (<0.01) to 28.6 μg g⁻¹ d.w. while particulate Cu ranged from below the detection limit (<0.04) to 53.5 μg g⁻¹ d.w. Cd in mesozooplankton ranged from below the detection limit (<0.01) to 37.4 μg g⁻¹ d.w. Some of the Cd levels were higher than those reported for other aquatic ecosystems. Cu in the mesozooplankton ranged from 1.3 to 89.3 μg g⁻¹ d.w., values which were within the reported values or higher than other studies. The log of the partition coefficients (log (K_d)) of Cd was 0.04, while log (K_d) for Cu ranged from −0.39 to 2.79. These values were lower than both those calculated for other estuaries and the typical coefficients for marine environments. The log of the bioconcentration factor (log BCF) of Cd was 1.78, indicating that Cd concentration was higher in the zooplankton than in the dissolved phase. Log BCF of Cu ranged from 1.15 to 3. The logs of the biomagnification factors (log BMF) of Cd were low, with a range between −3.45 and 2.21 and those for Cu ranged from −0.1 to 3.35. Positive values indicate biomagnification while negative values indicate biodiminution. In general, no significant dissolved Cd concentration appeared to be present in the Bahía Blanca estuary and Cu values did not indicate a critical environmental status. The particulate phase seemed to be the major carrier for Cd and Cu and TPCu values were within the normal values for an anthropogenically stressed estuary but not for a strongly polluted system. This fraction was the most important metal source for the mesozooplankton. Moreover, the highest metal concentrations were in the mesozooplankton since most of the bioconcentration and biomagnification factors were positive, especially for Cu.  相似文献   

Diversity patterns along and across the Chilean margin: a continental slope encompassing oxygen gradients and methane seep benthic habitats     

Javier Sellanes  Carlos Neira  Eduardo Quiroga  & Núria Teixido 《Marine Ecology》2010,31(1):111-124

In the present study we review datasets available for the Chilean margin to assess the relationship between environmental (or habitat) heterogeneity and benthic diversity. Several factors, such as the presence of different water masses, including the oxygen-deficient Equatorial Sub-surface Waters (ESSW) at the continental shelf and upper slope, and the Antarctic Intermediate Waters (AIW) at mid slope depths appear to control the bathymetric distribution of benthic communities. The presence of methane seeps and an extended oxygen minimum zone (OMZ) add complexity to the benthic distribution patterns observed. All these factors generate environmental heterogeneity, which is predicted to affect the diversity patterns both along and across the Chilean continental margin. The response to these factors differs among different faunal size groups: meio-, macro-, and megafauna. Physiological adaptations to oxygen deficiency and constraints related to body size of each group seem to explain the larger-scale patterns observed, while sediment/habitat heterogeneity ( e.g. at water mass boundaries, hardgrounds, biogeochemical patchiness, sediment organic content, grain size) may influence the local fauna diversity patterns.  相似文献   

Nature and origin of the BIF-hosted São Bento gold deposit, Quadrilátero Ferrífero, Brazil, with special emphasis on structural controls     

Srgio Luiz Martins Pereira  Lydia Maria Lobato  Juliano Efigênio Ferreira  Eduardo Csar Jardim 《Ore Geology Reviews》2007,32(3-4):571

The orogenic banded iron formation (BIF)-hosted Au mineralization at São Bento is a structurally-controlled, hydrothermal deposit hosted by Archean rocks of the Rio das Velhas greenstone belt, Quadrilátero Ferrífero region, Brazil. The deposit has reserves of 14.3 t Au and historical (underground) production of 44.6 t Au between 1987 and 2001. The oxide-facies São Bento BIF is mineralized at its lower portion, where in contact with carbonaceous, pelitic schists, particularly in the proximity of sulfide-bearing quartz veins. Shear-related Au deposition is associated with the pervasive, hydrothermal sulfidation (mainly arsenopyrite) of the Fe-rich bands of the São Bento BIF. Auriferous, sulfide- and quartz-rich zones represent proximal alteration zones. They are enveloped by ankerite-dominated haloes, which reflect progressive substitution of siderite and magnetite within the BIF by ankerite and pyrrhotite, respectively. The São Bento BIF was intensely and extensively deformed, first into open, upright folds that evolved into tight, asymmetric, isoclinal folds. The inverse limb of these folds attenuated and gave way to sheath folds and the establishment of ductile thrusts. Mineralized horizons at São Bento result from early structural modifications imposed by major transcurrent and thrusts faults, comprising the Conceição, Barão de Cocais and São Bento shear zones. Dextral movement on the SW–NE-directed Conceição shear zone may have generated splays at a compressional side-stepping zone, such as the São Bento shear zone, which is the structural locus for the São Bento gold mineralization. Relaxation of the Conceição shear zone under more brittle conditions resulted in the development of dilatational zones where gold–sulfide–quartz veins formed. These structures are considered to have been generated in the Archean. Geochronological data are scarce, with Pb–Pb analyses of refractory arsenopyrite and pyrite from bedded and remobilized ore plotting on a single-stage growth curve at 2.65 Ga. A later compressional, ductile deformation of unknown age overprinted, rotated and flattened the original, N60E-directed structure of the whole rock succession, with development of planar and linear fabrics that appear similar to Proterozoic-aged structures. Fluid inclusion studies indicate low salinity, aqueous fluids, with or without CO₂ and/or CH₄, with extremely variable CO₂/CH₄ ratios, of probable metamorphic origin. Fluid evolution shows a paragenetic decrease in the carbonic phase from 10–15% to 5%, and increase in the H₂O/(CO₂ + CH₄) and CO₂/CH₄ ratios, suggesting important interaction with carbonaceous sediment. Trapping conditions indicate a temperature of 300 °C at 3.2 kbar.  相似文献   

A short-term forecast model for hail     

Laura Lpez  Eduardo García-Ortega  Jos Luis Snchez 《Atmospheric Research》2007,83(2-4):176-184

Predicting the occurrence of hailstorms is one of the most complicated tasks in weather forecasting because of the small area of land that is usually affected, and because of the short time hail events last. Today there are a number of parameters available that may be used to characterize preconvective conditions and predict the beginning of convection. However, forecast models based on stability indices should be developed separately for each geographic area.The databases available were used in this study with two aims in mind: determining which meteorological variables or indices obtained from a radiosonde in the study zone are more relevant in characterizing preconvective conditions; and, secondly, setting up an objective short-term forecast model for storms on the basis of one or more meteorological parameters.The logistic regression was used to establish the dichotomy risk/no risk of storms. A function was developed combining seven meteorological variables. The results show that the forecast model has a Probability of Detection of 0.87 and a False Alarm Ratio of 0.18.  相似文献   

Ages and metallicities of five intermediate-age star clusters projected towards the Small Magellanic Cloud     

Andrés E. Piatti  João F. C. SantosJr  Juan J. Clariá  Eduardo Bica  Ata Sarajedini  Doug Geisler 《Monthly notices of the Royal Astronomical Society》2001,325(2):792-802

Colour–magnitude diagrams are presented for the first time for L32, L38, K28 (L43), K44 (L68) and L116, which are clusters projected on to the outer parts of the Small Magellanic Cloud (SMC). The photometry was carried out in the Washington system C and T ₁ filters, allowing the determination of ages by means of the magnitude difference between the red giant clump and the main-sequence turn-off, and metallicities from the red giant branch locus. The clusters have ages in the range 2–6 Gyr , and metallicities in the range −1.65<[Fe/H]<−1.10, increasing the sample of intermediate-age clusters in the SMC. L116, the outermost cluster projected on to the SMC, is a foreground cluster, and somewhat closer to us than the Large Magellanic Cloud. Our results, combined with those for other clusters in the literature, show epochs of sudden chemical enrichment in the age–metallicity plane, which favour a bursting star formation history as opposed to a continuous one for the SMC.  相似文献   

Behavior of the fresh- and saline-water phases in an urban area in Western Buenos Aires Province, Argentina     

Luis Vives  Marcelo Varni  Eduardo Usunoff 《Hydrogeology Journal》2005,13(2):426-435

Given the particular hydrogeological setting at Salliqueló County, Western Buenos Aires Province, Argentina, this paper places attention on the lens that supplies fresh water to its capital, Salliqueló. This lens constitutes the most important fresh-water reservoir in the county. It overlies saline waters, and is recharged through high-permeability sandy sediments at a rate that exceeds by far the actual water demand. Restrictions in exploitation are not limited by the total requirement but rather by the flows extracted from individual wells that may generate up-coning of saline waters, with a resulting overall deterioration in quality of the pumped water. The variations in the position of the interface between saline and fresh waters, as related to the change in extraction rates, were obtained by means of a simulation of the flow of two fluids of different densities. Finally, based on the general hydrogeological characterization and on the simulation results, various methods for the management of these fresh-water resources are proposed, such as the deactivation of urban supply wells, the monitoring of the saline interface position, and the establishment of a protection perimeter for the water-supply wells.

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Resumen Enmarcado dentro de las características hidrogeológicas generales del partido de Salliqueló, oeste de la provincia de Buenos Aires, Argentina, este trabajo se centra en la lente que abastece de agua dulce a Salliqueló, la capital del partido. Esta lente constituye la reserva de agua dulce más importante del partido, se ubica sobre aguas salinas y es recargada a través de sedimentos arenosos de alta permeabilidad a una tasa que excede grandemente los requerimientos de la población. Sin embargo, las restricciones en la explotación no están dadas por las demandas totales sino por las extracciones en perforaciones individuales, que pueden generar ascensos de agua salina con el consiguiente deterioro en la calidad del agua extraída. Las variaciones de la posición de la interfase respecto de los cambios en la explotación fueron obtenidas por medio de la simulación del flujo de dos fluidos de diferente densidad. Finalmente, con base en la caracterización hidrogeológica general y en los resultados de la simulación, se proponen varias medidas para la protección del recurso hídrico, tales como: la desactivación de los pozos de abastecimiento en el ámbito urbano, el control de la posición de la interfase salina y la definición de perímetros de protección de los pozos de abastecimiento, entre otras.

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Résumé Etant donné les particularités hydrogéologiques de la région de Salliqueló, ouest de la province de Buenos Aires, Argentine, cet article traite de la lentille deau douce alimentant en eau potable la capitale, Salliqueló. Cette lentille constitue la réserve la plus importante deau douce de la région. Elle se superpose aux eaux salées et est rechargée via les sédiments sableux et perméables, à un taux dépassant largement la demande actuelle en eau. Les restrictions dans lexploitation ne sont pas limitées par la demande totale mais par les débits extraits des forages privés, qui pourraient générer des rabattements induisant des arrivées deaux salées, arrivées qui peuvent dégrader la ressource pompée. Les variations de la position de linterface eau douce–eau salée, en relation avec les taux dexploitation, ont été obtenues en simulant lécoulement de deux fluides de différentes densités. Finalement, sur base dune caractérisation hydrogéologique et des résultats de la simulation, des méthodes variées pour la gestion de la ressource en eau douce sont proposées, entre autre, la désactivation de pompages urbains, suivi de linterface eau douce–eau salée, et la mise en place de zones de protections des captages deau souterraine.

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