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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Untersuchungen zur Quantifizierung der Grundwasserimmission von polyzyklischen aromatischen Kohlenwasserstoffen mithilfe von passiven Probennahmesystemen

Börke, Peter 05 October 2007 (has links) (PDF)
Kern der Arbeit bildete die Entwicklung einer Fluxmeter-Passivsammlereinheit für hydrophobe organische Substanzen im Grundwasser kontaminierter Standorte sowie deren Testung im Feld. Ferner kamen Keramik-Dosimeter unter identischen Feldbedingungen zum Einsatz. Die Ergebnisse der beiden passiven Sammelsysteme wurden mit herkömmlicher Grundwasserprobennahmetechnik mithilfe von Unterwassermotorpumpen verglichen und bewertet. Grundlage für den Einsatz der Passivsammlereinheit als „mass flux meter“ bildete die Kenntnis über den Volumenstrom im Bohrloch und den reduzierten Volumenstrom in der Passivsammlereinheit und andererseits über die räumliche Verteilung der hydraulischen Durchlässigkeit und der daraus resul¬tierenden heterogenen Geschwindigkeitsverteilung bzw. der Volumenströme über so genannte Kontroll¬ebenen bzw. Teilbilanzräume. Anhand numerischer Modelluntersuchungen konnten der Filterwiderstand der Passivsammlereinheit und die Strömungsverteilung in Modellkontrollebenen und im Feld näherungsweise bestimmt werden. Die Bestimmung des Volumenstromes des untersuchten Standortes wurde zum einen mithilfe von numerischen Modelluntersuchungen an stochastisch generierten quasi-3-dimensionalen Modellen mit hydro¬dynamischen Randbedingungen und kF-Wertverteilungen aus dem Feld und zum anderen mithilfe von Einbohrlochverfahren durchgeführt. Als Einbohrlochverfahren kamen zum einen ein optisches Kolloid-Logging (Grundwasserfluss-Visualisierungssystem) und zum anderen ein modifiziertes Fluidlogging-Verfahren mit Hilfe eines Salztracers zum Einsatz.
12

Novel Integrative Methods for Sampling Environmental Contaminants

January 2015 (has links)
abstract: Up to 25 percent of the operating budget for contaminated site restoration projects is spent on site characterization, including long-term monitoring of contaminant concentrations. The sensitivity, selectivity, and reproducibility of analytical methods have improved to the point where sampling techniques bear the primary responsibility for the accuracy and precision of the data. Most samples represent discrete concentrations in time and space; with sampling points frequently limited in both dimensions, sparse data sets are heavily extrapolated and the quality of data further limited. Methods are presented for characterizing contaminants in water (groundwater and surface waters) and indoor air. These techniques are integrative, providing information averaged over time and/or space, as opposed to instantaneous point measurements. Contaminants are concentrated from the environment, making these methods applicable to trace contaminants. These methods have the potential to complement existing techniques, providing the practitioner with opportunities to reduce costs and improve the quality of the data used in decision making. A conceptual model for integrative sampling of environmental waters is developed and a literature review establishes an advantage in precision for active samplers. A programmable sampler was employed to measure the concentration of chromate in a shallow aquifer exhibiting time-dependent contaminant concentrations, providing a unique data set and sustainability benefits. The analysis of heat exchanger condensate, a waste stream generated by air conditioning, is demonstrated in a non-intrusive method for indoor air quality assessment. In sum, these studies present new opportunities for effective, sustainable environmental characterization. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2015
13

Mapeamento de níveis freáticos do sistema aquífero bauru (SAB) em área de proteção ambiental em Águas de Santa Bárbara/SP durante o ano hidrológico 2014/15 / Mapping water table depths of Bauru aquifer system (BAS) in a enviromental protection area at Águas de Santa Barbara/SP - Brazil during the 2014/2015 hydological year

Santarosa, Lucas Vituri [UNESP] 10 August 2016 (has links)
Submitted by Lucas Vituri Santarosa null (lucasviturisantarosa@gmail.com) on 2016-09-08T19:18:59Z No. of bitstreams: 1 Dissertação_LucasSantarosa_final com ficha.pdf: 7860653 bytes, checksum: 6aa2806898b067c2a01afa0656925a2f (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-12T20:10:19Z (GMT) No. of bitstreams: 1 santarosa_lv_me_bot.pdf: 7860653 bytes, checksum: 6aa2806898b067c2a01afa0656925a2f (MD5) / Made available in DSpace on 2016-09-12T20:10:19Z (GMT). No. of bitstreams: 1 santarosa_lv_me_bot.pdf: 7860653 bytes, checksum: 6aa2806898b067c2a01afa0656925a2f (MD5) Previous issue date: 2016-08-10 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A estatística espacial aplicada a coleta de dados, análise e interpretação de fenômenos espaciais é uma ferramenta importante para gestão dos recursos hídricos, exigindo modelos matemáticos precisos e com capacidade de determinar as incertezas. Assim, as metodologias geoestatísticas apresentam-se como uma alternativa para análise de dados voltados ao monitoramento dos aquíferos coletados em redes geoespaciais, reduzindo os efeitos relacionados à amostragem e agregando sentido físico a análise. Este trabalho explorou o uso da geoestatística no mapeamento da dinâmica de níveis freáticos do Sistema Aquífero Bauru (SAB), comparando interpoladores como krigagem e cokrigagem, em condições de amostragem anisotópica. Foram utilizadas como variáveis auxiliares as propriedades físico-hídricas do solo e do relevo para o mapeamento dos níveis freáticos do ano hidrológico 2014/2015 e 2015/2016 a partir de 48 poços de monitoramento localizados nos domínios da Estação Ecológica de Santa Bárbara (EEcSB), município de Águas de Santa Bárbara/SP. Os objetivos foram verificar a oscilações do nível freático em uma área do SAB, estimar os volumes recuperados e reunir informações para formular um Modelo Hidrogeológico Conceitual (MHC). Os resultados mostraram que a adoção das variáveis auxiliares, sobretudo dados topográficos e resistência do solo a penetração, são capazes de melhorar as estimativas espaciais, com visível redução da variância amostral, suavizando os erros nas predições. Os volumes de água recuperados calculados a partir dos mapas do nível freático revelam a capacidade do uso de áreas como a EEcSB para o estoque de águas subterrâneas em curto prazo, capaz de suprir a demanda regional em períodos de escassez. Com a previsão da captação de 30% do volume de água recuperado na EEcSB estima-se o abastecimento da população dos municípios de Manduri, Cerqueira Cesar e Águas de Santa Bárbara por cerca de três meses. Com os dados ambientais reunidos foi formulado um MHC a partir da estimativa da dinâmica da água subterrânea. Os resultados apresentados são importantes no auxílio da gestão das águas subterrâneas com informações estratégicas para o uso sustentável de aquíferos a partir da direção de escoamento natural do aquífero e do comportamento da oscilação do nível freático em relação ao regime pluviométrico. / The spatial statistics applied to data collection, analysis and interpretation of spatial phenomena has become essential for management of water resources, requiring accurate mathematical models and the ability to determine the uncertainties. Therefore, geostatistics presented as an important tool for data analysis aimed at monitoring of aquifer collected in geospatial networks, reducing the effects related at data collection and merging physical sense in the analyses. This study explored the use of geostatistics in mapping the dynamic of Bauru Aquifer System (BAS), comparing interpolators as kriging and cokriging in anisotopic sampling conditions. Were used as auxiliary variables the physical and hydraulic of the soil and the topography for the mapping of water table deep of the hydrological year 2014/2015 and 2015/2016 onwards of 48 monitoring wells located in the Ecological Station of Santa Barbara (EEcSB) domain, in Águas de Santa Barbara, Sao Paulo, Brazil. The objectives were to verify the fluctuations of water table in an area the BAS, estimate the recovered water volumes and gather information for the formulation of the Hydrological Conceptual Model (HCM). The results showed that the using of the auxiliary variables, mainly topographic data and soil resistance penetration, are able to improve the spatial predictions, with notable reductions at sampling variance and decreasing errors in the predictions. The water volumes recovered calculated from the water table maps allowed to infer about the ability of the use at areas as the EEcSB for the groundwater storage in short term, able to supply the regional demand in periods of scarcity. With the forecast of 30% uptake of the water volume recovered in EEcSB estimated to supply the population of the municipalities of Manduri, Cerqueira Cesar and Águas de Santa Barbara for approximately three months. With the collected environmental data allowed, the design of a HCM was formulated from the dynamics estimates of groundwater. The results are important supporting groundwater management with strategic information for sustainable use of aquifers. / FAPESP: 2015/05171-3
14

Presenza di erbicidi triazinici e loro metaboliti nelle acque di falda di aree maidicole italiane / PRESENCE OF TRIAZINE HERBICIDES AND THEIR METABOLITES IN GROUNDWATER OF ITALIAN MAIZE-GROWING AREAS

BOTTERI, LUCIO 01 March 2021 (has links)
La presenza di pesticidi nelle acque di falda è emersa come un importante problema ambientale negli ultimi decenni. In base a “Rapporto nazionale pesticidi nelle acque - Dati 2015-2016” (ISPRA, 2018), in Italia, gli erbicidi triazinici e i loro metaboliti sono tra le sostanze identificate con più frequenza nelle acque, sebbene l’atrazina sia stata bandita nel 1992 e l’utilizzo di terbutilazina sia sottoposto a severe restrizioni. Lo scopo di questo progetto è valutare e quantificare la presenza di atrazina, terbutilazina e dei loro metaboliti nelle acque di falda in aree maidicole italiane. I risultati dimostrano come le molecole oggetto di studio siano state frequentemente individuate nei campioni di acqua di falda, anche se a concentrazioni inferiori al limite stabilito dalla Commissione Europea. Considerando che l’utilizzo di questi erbicidi è proibito o fortemente regolamentato, è interessante valutare il loro comportamento in una scala temporale pluriennale al fine di mettere in evidenza la contaminazione delle acque di falda dovute all’uso diffuso e alla persistenza ambientale di tali molecole. / The presence of pesticides in groundwater has emerged as an important environmental issue in the last decades. According to “Rapporto nazionale pesticidi nelle acque - Dati 2015-2016” (ISPRA, 2018), in Italy triazine herbicides and their metabolites are among the substances most frequently detected in water. While terbuthylazine is still used under restriction, atrazine was banned in 1992. The aim of research project is to investigate the presence of atrazine, terbuthylazine and their metabolites in groundwater in Italian maize-growing areas in order to supply data and information on the groundwater quality. The results show that atrazine, terbuthylazine and their metabolites were often detected in groundwater, even if their concentrations were below the limit established by European Commission. Considering these molecules are banned or heavily regulated, it is interesting to evaluate their behavior on a multiannual time scale in order to highlight the groundwater contamination due to the widespread use and to the environmental persistence of these substances.
15

Part I. From the Lab to the Field - Recent Developments in Polymer Coated ATR Sensing for the Determination of Volatile Organic Compounds ; Part II. From the Field to the Lab - Investigating IR Signatures for Remote Sensing Applications

Karlowatz, Manfred 22 June 2004 (has links)
Part I: Successful transition of polymer coated, ATR-FTIR sensor devices from a laboratory environment to real world field applications for detecting and quantifying VOCs in water is shown. Simultaneous, quantitative detection of BTX mixtures in water during enrichment into polymer coated ZnSe ATR elements has been performed. The obtained results showed accurate detection and quantification to the low ppb concentration region. Fiber-optic evanescent field measurement campaigns have been conducted at simulated field conditions during which concentration gradients of various VOCs in the mg/L range have been monitored successfully. The first test of an ATR based, polymer coated sensor system under real world field conditions, the chlorobenzene concentration in groundwater at mg/L levels was determined. An interesting aspect of these measurements was the experimental proof for the dependence of analyte extraction dynamics on the flow conditions of the sample matrix surrounding the extractive polymer membrane. The obtained results demonstrate that MIR evanescent field sensors are suitable for in-situ analysis at real world field conditions for environmental monitoring applications. PART II: Recently, measurements of disturbed soils have shown different spectral contrast in comparison to undisturbed soils. In this work first measurements at controlled laboratory conditions have been performed to investigate individual minerals of the soil matrix and their spectral characteristics under various environmental conditions. ATR spectroscopy has been applied to investigate multi-disperse quartz sand and mono-disperse soda lime glass spheres samples. For the investigation of spectral differences between pristine and disturbed quartz sand, a wetting/drying procedure with subsequent sample aerating has been developed. In addition to established differences in spectral contrast of disturbed and undisturbed soil, a strong spectral shift of absorption features was observed. When probed with s- or p-polarized light, both samples showed strong LO-TO mode splitting. The studies also reveal that the main reason for spectral differences of pristine and disturbed soils is caused by water facilitated changes of the particle size distribution in the probed volume. The presented results advance the variety of spectral characteristics useful for the detection of disturbed soils (i.e. possible landmine sites) with MIR imaging systems.
16

Risk Based Post Closure Care Analysis for Florida Landfills

Sizirici Yildiz, Banu 24 March 2009 (has links)
Subtitle D of the Resource Conservation and Recovery Act (RCRA) requires a post closure period of 30 years for non hazardous wastes in landfills. Post closure care (PCC) activities under Subtitle D include leachate collection and treatment, groundwater monitoring, inspection and maintenance of the final cover, and monitoring to ensure that landfill gas does not migrate off site or into on site buildings. The decision to reduce PCC duration requires exploration of a performance based methodology to Florida landfills. PCC should be based on whether the landfill is a threat to human health or the environment. Historically no risk based procedure has been available to establish an early end to PCC. Landfill stability depends on a number of factors that include variables that relate to operations both before and after the closure of a landfill cell. Therefore, PCC decisions should be based on location specific factors, operational factors, design factors, post closure performance, end use, and risk analysis. The question of appropriate PCC period for Florida’s landfills requires in depth case studies focusing on the analysis of the performance data from closed landfills in Florida. Based on data availability, Davie Landfill was identified as case study site for a case by case analysis of landfill stability. The performance based PCC decision system developed by Geosyntec Consultants was used for the assessment of site conditions to project PCC needs. The available data for leachate and gas quantity and quality, ground water quality, and cap conditions were evaluated. The quality and quantity data for leachate and gas were analyzed to project the levels of pollutants in leachate and groundwater in reference to maximum contaminant level (MCL). In addition, the projected amount of gas quantity was estimated. A set of contaminants (including metals and organics) were identified as contaminants detected in groundwater for health risk assessment. These contaminants were selected based on their detection frequency and levels in leachate and ground water; and their historical and projected trends. During the evaluations a range of discrepancies and problems that related to the collection and documentation were encountered and possible solutions made. Based on the results of PCC performance integrated with risk assessment, projection of future PCC monitoring needs and sustainable waste management options were identified. According to these results, landfill gas monitoring can be terminated, leachate and groundwater monitoring for parameters above MCL and surveying of the cap integrity should be continued. The parameters which cause longer monitoring periods can be eliminated for the future sustainable landfills. As a conclusion, 30 year PCC period can be reduced for some of the landfill components based on their potential impacts to human health and environment (HH&E).
17

Untersuchungen zur Quantifizierung der Grundwasserimmission von polyzyklischen aromatischen Kohlenwasserstoffen mithilfe von passiven Probennahmesystemen

Börke, Peter 30 March 2007 (has links)
Kern der Arbeit bildete die Entwicklung einer Fluxmeter-Passivsammlereinheit für hydrophobe organische Substanzen im Grundwasser kontaminierter Standorte sowie deren Testung im Feld. Ferner kamen Keramik-Dosimeter unter identischen Feldbedingungen zum Einsatz. Die Ergebnisse der beiden passiven Sammelsysteme wurden mit herkömmlicher Grundwasserprobennahmetechnik mithilfe von Unterwassermotorpumpen verglichen und bewertet. Grundlage für den Einsatz der Passivsammlereinheit als „mass flux meter“ bildete die Kenntnis über den Volumenstrom im Bohrloch und den reduzierten Volumenstrom in der Passivsammlereinheit und andererseits über die räumliche Verteilung der hydraulischen Durchlässigkeit und der daraus resul¬tierenden heterogenen Geschwindigkeitsverteilung bzw. der Volumenströme über so genannte Kontroll¬ebenen bzw. Teilbilanzräume. Anhand numerischer Modelluntersuchungen konnten der Filterwiderstand der Passivsammlereinheit und die Strömungsverteilung in Modellkontrollebenen und im Feld näherungsweise bestimmt werden. Die Bestimmung des Volumenstromes des untersuchten Standortes wurde zum einen mithilfe von numerischen Modelluntersuchungen an stochastisch generierten quasi-3-dimensionalen Modellen mit hydro¬dynamischen Randbedingungen und kF-Wertverteilungen aus dem Feld und zum anderen mithilfe von Einbohrlochverfahren durchgeführt. Als Einbohrlochverfahren kamen zum einen ein optisches Kolloid-Logging (Grundwasserfluss-Visualisierungssystem) und zum anderen ein modifiziertes Fluidlogging-Verfahren mit Hilfe eines Salztracers zum Einsatz.
18

Groundwater chemistry and hydrological processes within a Quaternary coastal plain: Pimpama, Southeast Queensland

Harbison, John Edwin January 2007 (has links)
The Pimpama estuarine plain in subtropical southeast Queensland is comprised of Quaternary sediments infilling older bedrock. These multilayered unconsolidated sediments have various depositional origins, and are highly heterogeneous. The plain is low-lying and the surface drainage is controlled by flood mitigation measures including tidal gates and channelised streams. The control of surface drainage potentially affects the shallow water table. This modification of hydrology has implications for future viability of agriculture and also the environmental health of waterways. Increased landscape modification and water management is likely in the coming years. The combination of sediment heterogeneity, low hydraulic gradients, and artificial drainage modification result in the plain being hydrogeologically complex. In order to understand hydrologic processes in this setting, a multi-disciplinary research programme was conducted which included a drilling program, overland electromagnetic induction and other geophysical surveys (downhole gamma log, electromagnetic induction and magnetic susceptibility) to initially establish the geologic framework. These surveys were followed by hydrogeochemical testing which includes for major and minor ions and also stable isotopes, and mineralogical analysis of drillhole material. Underlying basement rock occurs at up to 60 m depth. Unconsolidated gravel and sand deposits occur within incised paleo-valleys and are overlain by predominantly low-permeability fluvial sandy clays and estuarine and lagoonal muds. Fine-grained delta sands occur in the top 15 m of the sub-surface. Within the unconsolidated sediments, hydrodynamic trends clearly discriminated between upper unconfined and lower semi-confined aquifer systems. A comparison of surface water and shallow groundwater levels indicate limited interaction of groundwater and surface water. Hydrogeochemical analysis effectively distinguished between groundwater bodies, and also distinguished saline groundwater from seawater. Trends in major ion chemistry in the semi-confined system (particularly Na/Cl and Ca/Cl ratios) showed ion exchange accompanying saline intrusion. However, due to factors such as mineral dissolution, major ion chemistry does not clearly identify solute flux trends in the shallow aquifer system. Water stable isotope analysis (δ18O and δ2H) indicated the provenance of fresh and saline groundwater and also the relative importance of the principal hydrologic processes, i.e. evaporation and water uptake by plants. Groundwater exhibited a wide range in salinity, from very fresh to hypersaline. The formation of hypersaline groundwater was attributed largely to uptake of water by mangrove forests. Since mangrove forests were more extensive at the time of the Holocene maximum sea level (approximately 6,000 years ago) than at present, some of this groundwater may represent relict salinity from this earlier time. The relationship of relict salinity to low permeability sediments, particularly at intermediate depths, and their depositional history was examined. Vertical salinity gradients and hydrogeochemistry within these sediments varied according to position within the plain, suggesting deposition under various hydrological and sea level regimes. A preliminary investigation using analysis of stable sulfate isotopes (δ34S and δ18OSO4) was made. This study shows substantial potential for the application of this technique for quantification of solute flux and sulfur chemical transformations within settings such as this coastal plain. To establish shallow groundwater flow processes, a MODFLOW-based numerical model was used to inversely estimate aquifer parameters under various recharge scenarios. The model was designed to examine the relative importance of evapotranspiration and discharge to surface waters. However, largely due to the complexity of the drainage network and non-uniform surface water flows, the quantification of surface water- groundwater interaction by consideration of hydrodynamics is problematic. Therefore, the chemistry of groundwater and surface water was compared. While the estimated contribution of rainfall to groundwater level fluctuations was significant (46%), high evapotranspiration rates reduced net recharge and it was concluded that baseflow to drains and creeks during dry periods was insignificant, and groundwater velocities in the shallow aquifer are low. The study illustrates the value of both hydrodynamic and hydrogeochemical analyses in estuarine settings where relict salinity and groundwater-aquifer interactions impact significantly on water quality. Saline groundwater is chemically distinct from theoretical mixtures of seawater and freshwater. The study also demonstrates the value of particular chemical parameters, e.g. Na/Cl and SO4/Cl ratios and stable water isotopes, for identifying hydrologic processes in this setting.

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