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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.
31

Développement de matériaux innovants à base d’élastomère de silicone pour l’échantillonnage passif de pesticides dans les eaux de surface et de subsurface / Development of innovative silicone rubber based materials for passive sampling of pesticides in surface and subsurface waters

Martin, Alexis 05 December 2016 (has links)
L'échantillonnage passif intégratif est de plus en plus reconnu comme une alternative à l'échantillonnage ponctuel pour la mesure des concentrations de micropolluants organiques dans les milieux aquatiques. Cette technique combine l'étape d'échantillonnage et de préconcentration in situ pour délivrer une concentration intégrée sur la durée d'exposition de l'échantillonneur passif (EP). Une des limitations principales de l'échantillonnage passif est la sélectivité imposée par la phase réceptrice pour une classe de contaminants restreinte (hydrophobes ou polaires). Ainsi, il est à l'heure actuelle nécessaire d'employer plusieurs EP pour mesurer des concentrations en pesticides caractérisés par une large gamme de polarité. L'objectif principal de cette thèse s'inscrit dans une démarche de développement de phases réceptrices pour l'échantillonnage passif de pesticides dans les milieux aquatiques. Afin de répondre à ce défi, nous avons sélectionné et formulé des matériaux pour la sorption de 28 pesticides aux propriétés physico-chimiques variées par le biais de tests en laboratoire. Nous avons d'une part sélectionné un élastomère de silicone de la marque Goodfellow® parmi 7 autres élastomères de silicone à partir de tests en laboratoire sur des critères de sorption. Nous avons démontré que les élastomères de silicone ont une forte affinité pour les pesticides plutôt hydrophobes, tout en accumulant également des pesticides polaires. Des propriétés de sorption différentes ont été identifiées selon leur formulation et un mécanisme d'adsorption est suspecté pour certains pesticides. D'autre part, nous avons formulé et testé plusieurs matériaux composites innovants dont le plus performant, renommé PACSiR, combine les propriétés de sorption d'un élastomère de silicone et d'un copolymère poreux (Oasis ® HLB). Nous avons mis en évidence que le PACSiR a des propriétés mécaniques adaptées pour une exposition directe dans le milieu aquatique et permet de capter une gamme de pesticides élargie vers les pesticides plus polaires par rapport à un élastomère de silicone. Ces deux matériaux ont été calibrés en laboratoire en tant qu'EP (TS à base de silicone et TSP à base de PACSiR), sous forme de tiges de petite dimension, afin de déterminer les constantes cinétiques d'accumulation et d'étudier l'impact de la vitesse de courant. Enfin, nous avons appliqué les TS et TSP dans des eaux de surface et de subsurface afin d'en évaluer et comparer les performances dans des situations contrastées d'exposition. La gamme d'utilisation de chaque EP en termes de polarité des pesticides a pu être définie (TS : 3 < log Kow < 5,5 et TSP : 2 < log Kow < 5,5.). Les concentrations en pesticides intégrées sur la durée d'exposition sont équivalentes à un échantillonnage d'eau moyenné au temps et les incertitudes sont du même ordre de grandeur sur les concentrations calculées. Ces EP ont permis de détecter des insecticides organophosphorés faiblement quantifiés par d'autres techniques de prélèvement d'eau. Nous avons démontré leur capacité à intégrer des pics de contamination fugaces en pesticides dans des contextes agricoles variés / Time integrative passive sampling is more and more accepted as an alternative to grab sampling for measurement of organic micropollutants concentrations in aquatic environment. This technique offers the advantage to provide a concentration integrated over the deployment period of the passive sampler and to reduce limit of quantification by combining sampling and in situ pre-concentration steps. The main limitation of passive sampling is the selectivity of the receiving phase for a restricted class of contaminants (hydrophobic or hydrophilic). In this way, we need to deploy several passive samplers for sampling of pesticides covering a wide range of polarities. The aim of this thesis was to develop a receiving phase for passive sampling of pesticides in a single step in aquatic environment.We selected and developed materials for sorption of 28 pesticides with varied physicochemical properties by laboratory tests. The two selected and studied materials were a silicone rubber and a porous copolymer (Oasis ® HLB). Indeed, we shown that silicone rubber have strong affinity for hydrophobic pesticides but they also accumulate polar pesticides. We identified different sorption properties of silicone rubbers owing to their formulation and a possible adsorption mechanism for some pesticides. The composite material developed had mechanical properties adapted for a direct exposition in the aquatic environment and accumulates a range of pesticides expanded for more polar pesticides. These two materials were then shaped as rods for a simple in situ deployment and recovery of pesticides in laboratory. They have been calibrated as passive samplers by studying the impact of flow velocity on uptake kinetic parameters. In situ applications of passive samplers in surface and subsurface waters made it possible to calculate time integrated concentrations of pesticides over a duration exposure of one week. Moreover, we detected organosphorous insecticides underquantified by other techniques of water sampling. They also showed a capacity to integrate short peak contamination of pesticides in various agricultural contexts
32

Mise au point d'un nouvel échantillonneur intégratif à base de solide naturel poreux / Development of a new passive sampler using a natural porous material

Ansanay-Alex, Salomé 19 December 2013 (has links)
L’échantillonnage passif est une alternative prometteuse à l’échantillonnage ponctuel. Cette technique permet d’accumuler les contaminants présents dans l’eau directement in-situ, intégrant ainsi les variations de concentrations temporelles qui ne sont pas détectables avec l’échantillonnage ponctuel. Cependant la plupart des échantillonneurs commercialisés actuellement utilisent des phases complexes et coûteuses. Ces travaux de thèse ont pour objectif de mettre au point un nouvel échantillonneur intégratif plus robuste et moins coûteux, capable d’échantillonner autant les contaminants métalliques que les composés organiques. Pour cela, l’idée était d’utiliser comme phase adsorbante un minéral naturel poreux doté de fortes capacités d’adsorption ; des zéolithes et une sépiolite naturelle ont été envisagées. Le développement d’un tel dispositif est un processus complexe qui passe tout d’abord par l’étude des capacités d’adsorption des différents solides pour les contaminants métalliques ainsi que pour les composés organiques. La comparaison des capacités d’adsorption des différents solides démontre que la sépiolite est la plus efficace pour la rétention de la majorité des contaminants étudiés. Sur la base de ces résultats la sépiolite est sélectionnée comme phase réceptrice du nouvel échantillonneur. Le déploiement de ces nouveaux dispositifs dans un milieu semi-contrôlé soumis à différents scénarios de contamination met en lumière une importante capacité d’échantillonnage tant pour les métaux que pour les contaminants organiques hydrophiles. Enfin, dans une dernière étape. / Passive sampling is a promising alternative to grab sampling. This approach consists in accumulating contaminants from water directly in-situ. Contrary to conventional grab sampling, this method allows integrating the temporal variations of the concentration. However most commercial samplers use complex and expensive adsorbent phases. In this work, we aimed to develop a new integrative sampler, more robust and less expensive than the commercial ones, able to sample both metals and organic compounds. For this the use of porous natural minerals with high adsorption capacities was investigated. Zeolites and natural sepiolite were considered. The development of this kind of device is a complex process involving a double approach laboratory/field. The first step consists in studying the adsorption capacity of different solids towards metals and organic compounds. The comparison of adsorption efficiency of different solids shows that sepiolite is the most efficient for the retention of most of the studied contaminants. Based on these results, it was selected as receiving phase of the new sampler. Deployment of these new devices in a semi-controlled environment with various scenarios of contamination was tested. This experiment highlighted that sepiolite has an important sampling ability both for metals and for hydrophilic organic contaminants. Finally, the last step of this process consisted in a validation of these samplers in a natural environment and in industrial effluent.
33

Présence et devenir des alkylphénols, de leurs dérivés et des composés pharmaceutiques dans les effluents : intérêt des échantillonneurs passifs

Soulier, Coralie 27 November 2012 (has links)
Le milieu aquatique est le réceptacle ultime de la pollution environnementale. De nombreux micropolluants y sont présents et montrent des effets toxiques envers les systèmes aquatiques. La Directive Cadre Eau (DCE) a comme objectif la restauration du bon état écologique et chimique des milieux aquatiques d’ici 2015. Pour cela, elle impose des Normes de Qualités Environnementales (NQE) faibles et une surveillance accrue des masses d’eau. Au-delà des micropolluants réglementés, certains dits « émergents » ont été détectés à de faibles concentrations (ng.L-1) dans les systèmes aquatiques. Sous ce terme, sont regroupés les composés pharmaceutiques, certains pesticides, les hormones, etc. L’ensemble de ces micropolluants sont introduits dans l’environnement par plusieurs sources : dépôts atmosphériques, lessivage des sols, lixiviation et rejets industriels et/ou domestiques. Ces travaux de thèse ont porté plus précisément sur les alkylphénols, présents sur la liste des contaminants prioritaires dangereux de la DCE, leurs dérivés éthoxylés, le bisphénol A et les composés pharmaceutiques. Dans un premier temps, une attention particulière a été portée à l’analyse de ces composés. Les méthodes analytiques de chromatographie liquide couplée à la spectrométrie de masse simple (LC-MS) et en tandem (LC-MS/MS) pour les alkylphénols ont été optimisées en améliorant les contrôles qualités et en portant une attention particulière à l’extraction des composés sensibles aux contaminations extérieures (manipulateur, ambiance, etc.). Pour pallier aux problèmes liés à la contamination des échantillons par ces composés lors de l’extraction, la microextraction sur phase solide (SPME) et une méthode d’analyse par chromatographie en phase gazeuse couplée à la spectrométrie de masse simple (GC-MS) ont été dévelopées. Dans un second temps, le devenir et le comportement des alkylphénols, de leurs dérivés éthoxylés et des composés pharmaceutiques dans les stations d’épuration (STEP), sources d’introduction dans les systèmes aquatiques avérées, ont été étudiés. Cette étude a permis de mettre en évidence que les concentrations diminuent au cours des traitements dans les STEP pour tous les composés étudiés sauf pour l’acide alkylphénoxy acétique (NP1EC) qui est formé au cours des traitements secondaires ; la carbamazépine et dans une moindre mesure le diclofénac restent stables. Seuls les traitements tertiaires permettent une élimination significative de ces composés. La présence à plus de 50% des alkylphénols et de leurs dérivés éthoxylés dans la phase particulaire entraînent une adsorption non négligeable de ces composés dans les boues. Dans le but d’améliorer le suivi environnemental, les POCISTM standard (« Polar Organic chemical Integrative SamplersTM ») de configuration « pharmaceutiques » ont été développés lors d’expérimentations menées en laboratoire pour l’échantillonnage des alkylphénols, de leurs dérivés éthoxylés, du bisphénol A et des composés pharmaceutiques. Les alkylphénols et leurs dérivés éthoxylés sont accumulés avec un temps de latence dans les POCISTM standard montrant l’influence de la membrane sur le transfert de masse de ces composés. Les POCISTM standards ont été optimisés en changeant la nature des membranes pour l’échantillonnage des alkylphénols et de leurs dérivés éthoxylés. Ces nouveaux outils sont nommés POCISTM-like. Les POCISTM-Nylon 0,1 µm et 30 µm sont les POCISTM-like montrant un fort pouvoir concentrateur des alkylphénols, de leurs dérivés éthoxylés et du Bisphénol A tout en éliminant le temps de latence observé dans leur accumulation dans les POCISTM standards. Ces POCISTM-like ont par la suite été validés en mésocosmes puis dans le milieu naturel afin de mettre en évidence leur caractère intégratif, permettant ainsi de s’affranchir de l’effet matriciel et de détecter certains composés à des concentrations inférieures aux limites de quantification. / The aquatic environment is the ultimate receptacle of environmental pollution. Many micro-pollutants are present and show toxic effects to aquatic systems (bioaccumulation in tissues, inhibition of growth, endocrine dysfunction, etc.). The Water Framework Directive (WFD) aims to restore the good ecological and chemical quality of aquatic environments by 2015. For this, it imposes low Environmental quality standards (EQS) and increased monitoring of water bodies. Beyond regulated micro-pollutants, some "emerging" have been detected at low concentrations (ng L-1) in aquatic systems. Under this term are grouped pharmaceutical compounds, some pesticides, hormones, etc. All of these micro-pollutants are introduced into the environment through several sources: atmospheric deposition, soil leaching and industrial or domestic discharges.This work is specifically focused on alkylphenols, present on the list of priority hazardous compounds in the WFD, their ethoxylated derivatives, bisphenol A and pharmaceutical compounds. As a first step, particular attention was paid to the analysis of these compounds. Analytical methods of liquid chromatography coupled to mass spectrometry (LC / MS) and tandem mass spectrometry (LC-MS/MS) for alkylphenols were optimized by improving quality controls and paying attention to the extraction of sensitive compounds toward contamination (manipulator, atmosphere, etc.). To overcome the problems associated with sample contamination by these compounds during the extraction, solid phase microextraction (SPME) and a method of analysis by gas chromatography coupled to mass spectrometry (GC-MS) was developed. In a second step, the fate and behavior of alkylphenols, their ethoxylated derivatives and pharmaceutical compounds in sewage treatment plants (WWTPs), sources of introduction into aquatic systems proved, were studied. This study has allowed showing the decrease of concentrations during treatment in WWTPs for all compounds studied except for alkylphenoxy acetic acid (NP1EC) which is formed during secondary treatment, carbamazepine, and to a lesser extent diclofenac remain stable. Only tertiary treatments allow significant removal of these compounds. The presence of more than 50% of alkylphenols and ethoxylated derivatives in the particulate phase lead to significant adsorption of these compounds into sludges. In order to improve environmental monitoring, during experiments conducted in the laboratory POCISTM standard (Polar Organic Chemical Integrative Samplers), "pharmaceuticals" configuration, have been developed for sampling alkylphenols, their ethoxylated derivates, bisphenol A and pharmaceutical compounds. Alkylphenols and their ethoxylated derivatives are accumulated with a lag phase in standard POCISTM showing the influence of the membrane on the mass transfer of these compounds. The standard POCISTM were optimized by changing the nature of the membranes for sampling alkylphenols and their ethoxylated derivatives. These new tools are named POCISTM-like. The POCISTM-Nylon 0.1 µm and 30 µm are POCISTM-like showing a strong power concentrator for alkylphénols, their ethoxylated derivatives and BPA while eliminating the lag phase observed in standard POCISTM. These POCISTM-like were subsequently validated in mesocosms and in the environment in order to highlight their integrative nature, allowing to overcome the matrix effect and to detect some compounds at concentrations below the limits of quantification.
34

Simulating and explaining passive air sampling rates and analyte air concentrations for semi-volatile compounds on polyurethane foam disks

Petrich, Nicholas Thomas 01 December 2012 (has links)
No description available.
35

Back-calculating emission rates for ammonia and particulate matter from area sources using dispersion modeling

Price, Jacqueline Elaine 15 November 2004 (has links)
Engineering directly impacts current and future regulatory policy decisions. The foundation of air pollution control and air pollution dispersion modeling lies in the math, chemistry, and physics of the environment. Therefore, regulatory decision making must rely upon sound science and engineering as the core of appropriate policy making (objective analysis in lieu of subjective opinion). This research evaluated particulate matter and ammonia concentration data as well as two modeling methods, a backward Lagrangian stochastic model and a Gaussian plume dispersion model. This analysis assessed the uncertainty surrounding each sampling procedure in order to gain a better understanding of the uncertainty in the final emission rate calculation (a basis for federal regulation), and it assessed the differences between emission rates generated using two different dispersion models. First, this research evaluated the uncertainty encompassing the gravimetric sampling of particulate matter and the passive ammonia sampling technique at an animal feeding operation. Future research will be to further determine the wind velocity profile as well as determining the vertical temperature gradient during the modeling time period. This information will help quantify the uncertainty of the meteorological model inputs into the dispersion model, which will aid in understanding the propagated uncertainty in the dispersion modeling outputs. Next, an evaluation of the emission rates generated by both the Industrial Source Complex (Gaussian) model and the WindTrax (backward-Lagrangian stochastic) model revealed that the calculated emission concentrations from each model using the average emission rate generated by the model are extremely close in value. However, the average emission rates calculated by the models vary by a factor of 10. This is extremely troubling. In conclusion, current and future sources are regulated based on emission rate data from previous time periods. Emission factors are published for regulation of various sources, and these emission factors are derived based upon back-calculated model emission rates and site management practices. Thus, this factor of 10 ratio in the emission rates could prove troubling in terms of regulation if the model that the emission rate is back-calculated from is not used as the model to predict a future downwind pollutant concentration.
36

Development and application of a new passive sampling device : the lipid-free tube (LFT) sampler

Quarles, Lucas W. 29 September 2009 (has links)
Contaminants can exist in a wide range of states in aqueous environments, especially in surface waters. They can be freely dissolved or associated with dissolved or particulate organic matter depending on their chemical and physical characteristics. The freely dissolved fraction represents the most bioavailable fraction to an organism. These freely dissolved contaminants can cross biomembranes, potentially exerting toxic effects. Passive sampling devices (PSDs) have been developed to aid in sampling many of these contaminants by having the ability to distinguish between the freely dissolved and bound fraction of a contaminant. A new PSD, the Lipid-Free Tube (LFT) sampler was developed in response to some of the shortcomings of other current PSD that sample hydrophobic organic contaminants (HOCs). The device and laboratory methods were original modeled after a widely utilized PSD, the semipermeable membrane device (SPMD), and then improved upon. The effectiveness, efficiency, and sensitivity of not only the PSD itself, but also the laboratory methods were investigated. One requirement during LFT development was to ensure LFTs could be coupled with biological analyses without deleterious results. In an embryonic zebrafish developmental toxicity assay, embryos exposed to un-fortified LFT extracts did not show significant adverse biological response as compared to controls. Also, LFT technology lends itself to easy application in monitoring pesticides at remote sampling sites. LFTs were utilized during a series of training exchanges between Oregon State University and the Centre de Recherches en Ecotoxicologie pour le Sahel (CERES)/LOCUSTOX laboratory in Dakar, Senegal that sought to build "in country" analytical capacity. Application of LFTs as biological surrogates for predicting potential human health risk endpoints, such as those in a public health assessment was also investigated. LFT mass and accumulated contaminant masses were used directly, representing the amount of contaminants an organism would be exposed to through partitioning assuming steady state without metabolism. These exposure concentrations allow for calculating potential health risks in a human health risk model. LFT prove to be a robust tool not only for assessing bioavailable water concentrations of HOCs, but also potentially providing many insights into the toxicological significance of aquatic contaminants and mixtures. / Graduation date: 2010
37

New Calibration Approaches in Solid Phase Microextraction for On-Site Analysis

Chen, Yong January 2004 (has links)
Calibration methods for quantitative on-site sampling using solid phase microextraction (SPME) were developed based on diffusion mass transfer theory. This was investigated using adsorptive polydimethylsiloxane/divinylbenzene (PDMS/DVB) and Carboxen/polydimethylsiloxane (CAR/PDMS) SPME fiber coatings with volatile aromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and o-xylene) as test analytes. Parameters that affected the extraction process (sampling time, analyte concentration, water velocity, and temperature) were investigated. Very short sampling times (10-300 s) and sorbents with a strong affinity and large capacity were used to ensure a 'zero sink' effect calibrate process. It was found that mass uptake of analyte changed linearly with concentration. Increase of water velocity increased mass uptake, though the increase is not linear. Temperature did not affect mass uptake significantly under typical field sampling conditions. To further describe rapid SPME analysis of aqueous samples, a new model translated from heat transfer to a circular cylinder in cross flow was used. An empirical correlation to this model was used to predict the mass transfer coefficient. Findings indicated that the predicted mass uptake compared well with experimental mass uptake. The new model also predicted rapid air sampling accurately. To further integrate the sampling and analysis processes, especially for on-site or <i>in-vivo</i> investigations where the composition of the sample matrix is very complicated and/or agitation of the sample matrix is variable or unknown, a new approach for calibration was developed. This involved the loading internal standards onto the extraction fiber prior to the extraction step. During sampling, the standard partially desorbs into the sample matrix and the rate at which this process occurs, was for calibration. The kinetics of the absorption/desorption was investigated, and the isotropy of the two processes was demonstrated, thus validating this approach for calibration. A modified SPME device was used as a passive sampler to determine the time-weighted average (TWA) concentration of volatile organic compounds (VOCs) in air. The sampler collects the VOCs by the mechanism of molecular diffusion and sorption on to a coated fiber as collection medium. This process was shown to be described by Fick's first law of diffusion, whereby the amount of analyte accumulated over time enable measurement of the TWA concentration to which the sampler was exposed. TWA passive sampling with a SPME device was shown to be almost independent of face velocity, and to be more tolerant of high and low analyte concentrations and long and short sampling times, because of the ease with which the diffusional path length could be changed. Environmental conditions (temperature, pressure, relative humidity, and ozone) had little or no effect on sampling rate. When the SPME device was tested in the field and the results compared with those from National Institute of Occupational Health and Safety (NIOSH) method 1501 good agreement was obtained. To facilitate the use of SPME for field sampling, a new field sampler was designed and tested. The sampler was versatile and user-friendly. The SPME fiber can be positioned precisely inside the needle for TWA sampling, or exposed completely outside the needle for rapid sampling. The needle is protected within a shield at all times hereby eliminating the risk of operator injury and fiber damage. A replaceable Teflon cap is used to seal the needle to preserve sample integrity. Factors that affect the preservation of sample integrity (sorbent efficiency, temperature, and sealing materials) were studied. The use of a highly efficient sorbent is recommended as the first choice for the preservation of sample integrity. Teflon was a good material for sealing the fiber needle, had little memory effect, and could be used repeatedly. To address adsorption of high boiling point compounds on fiber needles, several kinds of deactivated needles were evaluated. RSC-2 blue fiber needles were the more effective. A preliminary field sampling investigation demonstrated the validity of the new SPME device for field applications.
38

New Calibration Approaches in Solid Phase Microextraction for On-Site Analysis

Chen, Yong January 2004 (has links)
Calibration methods for quantitative on-site sampling using solid phase microextraction (SPME) were developed based on diffusion mass transfer theory. This was investigated using adsorptive polydimethylsiloxane/divinylbenzene (PDMS/DVB) and Carboxen/polydimethylsiloxane (CAR/PDMS) SPME fiber coatings with volatile aromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and o-xylene) as test analytes. Parameters that affected the extraction process (sampling time, analyte concentration, water velocity, and temperature) were investigated. Very short sampling times (10-300 s) and sorbents with a strong affinity and large capacity were used to ensure a 'zero sink' effect calibrate process. It was found that mass uptake of analyte changed linearly with concentration. Increase of water velocity increased mass uptake, though the increase is not linear. Temperature did not affect mass uptake significantly under typical field sampling conditions. To further describe rapid SPME analysis of aqueous samples, a new model translated from heat transfer to a circular cylinder in cross flow was used. An empirical correlation to this model was used to predict the mass transfer coefficient. Findings indicated that the predicted mass uptake compared well with experimental mass uptake. The new model also predicted rapid air sampling accurately. To further integrate the sampling and analysis processes, especially for on-site or <i>in-vivo</i> investigations where the composition of the sample matrix is very complicated and/or agitation of the sample matrix is variable or unknown, a new approach for calibration was developed. This involved the loading internal standards onto the extraction fiber prior to the extraction step. During sampling, the standard partially desorbs into the sample matrix and the rate at which this process occurs, was for calibration. The kinetics of the absorption/desorption was investigated, and the isotropy of the two processes was demonstrated, thus validating this approach for calibration. A modified SPME device was used as a passive sampler to determine the time-weighted average (TWA) concentration of volatile organic compounds (VOCs) in air. The sampler collects the VOCs by the mechanism of molecular diffusion and sorption on to a coated fiber as collection medium. This process was shown to be described by Fick's first law of diffusion, whereby the amount of analyte accumulated over time enable measurement of the TWA concentration to which the sampler was exposed. TWA passive sampling with a SPME device was shown to be almost independent of face velocity, and to be more tolerant of high and low analyte concentrations and long and short sampling times, because of the ease with which the diffusional path length could be changed. Environmental conditions (temperature, pressure, relative humidity, and ozone) had little or no effect on sampling rate. When the SPME device was tested in the field and the results compared with those from National Institute of Occupational Health and Safety (NIOSH) method 1501 good agreement was obtained. To facilitate the use of SPME for field sampling, a new field sampler was designed and tested. The sampler was versatile and user-friendly. The SPME fiber can be positioned precisely inside the needle for TWA sampling, or exposed completely outside the needle for rapid sampling. The needle is protected within a shield at all times hereby eliminating the risk of operator injury and fiber damage. A replaceable Teflon cap is used to seal the needle to preserve sample integrity. Factors that affect the preservation of sample integrity (sorbent efficiency, temperature, and sealing materials) were studied. The use of a highly efficient sorbent is recommended as the first choice for the preservation of sample integrity. Teflon was a good material for sealing the fiber needle, had little memory effect, and could be used repeatedly. To address adsorption of high boiling point compounds on fiber needles, several kinds of deactivated needles were evaluated. RSC-2 blue fiber needles were the more effective. A preliminary field sampling investigation demonstrated the validity of the new SPME device for field applications.
39

Back-calculating emission rates for ammonia and particulate matter from area sources using dispersion modeling

Price, Jacqueline Elaine 15 November 2004 (has links)
Engineering directly impacts current and future regulatory policy decisions. The foundation of air pollution control and air pollution dispersion modeling lies in the math, chemistry, and physics of the environment. Therefore, regulatory decision making must rely upon sound science and engineering as the core of appropriate policy making (objective analysis in lieu of subjective opinion). This research evaluated particulate matter and ammonia concentration data as well as two modeling methods, a backward Lagrangian stochastic model and a Gaussian plume dispersion model. This analysis assessed the uncertainty surrounding each sampling procedure in order to gain a better understanding of the uncertainty in the final emission rate calculation (a basis for federal regulation), and it assessed the differences between emission rates generated using two different dispersion models. First, this research evaluated the uncertainty encompassing the gravimetric sampling of particulate matter and the passive ammonia sampling technique at an animal feeding operation. Future research will be to further determine the wind velocity profile as well as determining the vertical temperature gradient during the modeling time period. This information will help quantify the uncertainty of the meteorological model inputs into the dispersion model, which will aid in understanding the propagated uncertainty in the dispersion modeling outputs. Next, an evaluation of the emission rates generated by both the Industrial Source Complex (Gaussian) model and the WindTrax (backward-Lagrangian stochastic) model revealed that the calculated emission concentrations from each model using the average emission rate generated by the model are extremely close in value. However, the average emission rates calculated by the models vary by a factor of 10. This is extremely troubling. In conclusion, current and future sources are regulated based on emission rate data from previous time periods. Emission factors are published for regulation of various sources, and these emission factors are derived based upon back-calculated model emission rates and site management practices. Thus, this factor of 10 ratio in the emission rates could prove troubling in terms of regulation if the model that the emission rate is back-calculated from is not used as the model to predict a future downwind pollutant concentration.
40

Environmental and socio-economic determinants, their impacts on trace metals and pharmaceuticals in watercourses : a comparison on two watersheds of France and Ukraine / Déterminants environnementaux et socio-économiques, leur influence sur les métaux traces et les produits pharmaceutiques dans les cours d’eau

Vystavna, Yuliya 09 March 2012 (has links)
Les objectifs de cette étude comparative de deux bassins versants en France et en Ukraine» sont de trois ordres : i) déterminer l’occurrence des micropolluants émergents (métaux traces et molécules pharmaceutiques) dans les eaux de surface, ii) permettre leur évaluation qualitative et quantitative et enfin iii) estimer leur distribution en fonction du contexte socio-économique. Cette recherche porte sur l'analyse de l'origine, sur les propriétés physico-chimiques et sur le comportement des micropolluants (métaux traces et molécules pharmaceutiques) dans les eaux de surface des rivières Jalle (Bordeaux, France) et Udy & Lopan (Kharkiv, Ukraine). Un suivi des métaux traces et des produits pharmaceutiques dans les eaux naturelles de surface dans différents contextes et conditions climatiques a été réalisé. La description et l'analyse des facteurs environnementaux et socio-économiques influençant l’hydrochimie locale en vue de conclure sur l’opportunité et l'intérêt des micropolluants émergents comme indicateurs anthropiques du contexte socio-économique et environnemental d‘un bassin versant ont été mis en œuvre. L’étude a combiné des techniques de prélèvements d’échantillons d’eau classiques et par capteurs passifs in situ. L’analyse semi quantitative des micropolluants émergents a porté sur les métaux traces (sonde DGT) et les produits pharmaceutiques (POCIS). L’usage de ces capteurs a permis d’évaluer les différentes formes d'éléments, les sources, les variations saisonnières et spatiales, l'accumulation et les risques environnementaux. A partir des données environnementales collectées, acquises, actualisées et validées il a été possible de modéliser la consommation régionale de médicaments dans le cas de (1) la région de Kharkiv, en Ukraine, sur les rivières Lopan et Udy du bassin Seversky Donets et (2) la région de Bordeaux, en France, sur la rivière Jalle, du bassin de la Garonne. Les sites ont été sélectionnés pour représenter une diversité tant du point de vue de l'état de pollution des eaux (nature et flux) que de celui du paysage socio-économique (contexte urbain, social et indicateurs économiques). Les résultats majeurs de cette étude sont : (i) méthodologique pour le développement et la validation de protocoles d’échantillonnage classique et passif (intérêt, limites, recommandations), ii) analytique quant à la mesure des éléments traces des eaux de surface naturelles dans des conditions extrêmes, iii) scientifique par l’obtention d’un jeu de données sur l’hydrochimie des éléments traces ( présence, accumulation, origine et variabilité spatiale et temporelle et iv) prospectif quant à l’usage des métaux traces et de produits pharmaceutiques comme traceurs anthropiques de l’état des eaux naturelles de surfaces et reflet du contexte socio-économique. La modélisation socio-économique (statistique) et environnementale (balance de masse) aide à comprendre l’évolution de la qualité des eaux de surface dans leur contexte régional et permet d’identifier certains contaminants comme des indicateurs des activités anthropiques d’un bassin versant et permet de définir une typologie. L’ensemble des résultats de la thèse sont présentés sous la forme d'articles publiés ou soumis dans des revues scientifiques internationales. / The PhD study focuses on the understanding of processes of the impact of environmental and socio-economic determinants on the occurrence, accumulation and distribution of trace metals and pharmaceuticals in urban watercourses. The research has been based on the analysis of the origin; physico-chemical properties and behavior of trace pollutants. The study was performed in two general steps: (i) monitoring of trace metals and pharmaceuticals in natural waters; (ii) description and analysis of environmental and socio-economic determinants that influence the water chemistry and (iii) evaluation of trace pollutants as environmental and socio-economic indicators. The monitoring of trace metals in natural water was proceed using the combination of passive and grab water sampling techniques, in order to evaluate various forms of elements, sources, seasonal and spatial variations, accumulation and environmental risks associated with the presence of contaminants in the study areas. The monitoring of pharmaceuticals was done using passive sensors to determine their capacity to register chemicals variation in time and adequation to use environmental data for the regional medicament consumption modeling. Monitoring data were also investigated in term of potential applications of trace metals and pharmaceuticals as environmental and socio-economic indicators. Two study sites were chosen: (1) the Kharkiv region in Ukraine where research was focused on the Lopan and Udy rivers of the Seversky Donets water basin and (2) the Bordeaux region in France where water monitoring was done in the Jalle River, Garonne water basin. Sites were mainly selected to represent the water pollution status in different socio-economic regions. General PhD results can be described as follows:1. The methodology for pilot and continuous monitoring of trace elements in the water with combination of traditional (grab) and innovative (passive) sampling procedures help to get data on trace elements presence, accumulation and sources, considering time variations.2. The analysis of trace metals and pharmaceuticals in two river basins of France and Ukraine and determination of environmental factors that impact on the occurrence, accumulation and distribution of these chemicals.3. The establishment of links between regional socio-economic issues and water quality data. The socio-economic and environmental modeling helps us to understand the water pollution process in regional context and give the opportunity to propose contaminants as tracers of anthropogenic activities and water quality assessment.Results of the PhD study are presented in the form of published or submitted peer-reviewed articles. / Диссертация «Экологические и социально-экономические факторы распространения металлов и фармацевтических веществ в природных водах: на примере рек Харькова, Украина и Бордо, Франция» на соискание степени Доктора Философии (Environmental Science) подготовлена в рамках договора о научном сотрудничестве и совместном руководстве между Университетом Бордо, Франция и Харьковской национальной академией городского хозяйства, Украина.Актуальность работы связана с сушествующими проблемами мониторинга природных вод, недостатком исследований микро-загрязнителей водотоков как во Франции, так и в Украине, существующим экологическим риском, который возникает при поступлении и накоплении металов и фармацевтических веществ в урбанизированных водотоках, а также возможностью использования химических веществ в качестве экологических и социально – экономических индикаторов. Целью диссертационной работы стало усовершенствование методов мониторинга микро-загрязнителей в природных водах и оценка возможности использования отдельных микро-загрязнителей в качестве экологических и социально-экономических показателей. Предметом исследования являются экологические и социально-экономические факторы, влияющие на распространение металлов и фармацевтических веществ в природных водах. Объектом исследования стали реки Уды и Лопань, Харьковская область, Украина и река Жаль, регион Бордо, Франция.Основные задачи: (1) провести мониторинг рек на различные формы металлов и фармацевтические вещества с применением стандартных и инновационных (пассивных) методов отбора проб; (2) опеределить экологические и социально- экономические факторы, которые влияют на распространение микрозагрязнителей в природных водах; (3) изучить возможность использования металлов и фармацевтических веществ в качестве индикаторов антропогенного загрязнения природных вод.В результате проведенных исследований был: Впервые: (а) осуществлен мониторинг лабильных форм металлов в реках бассейна Северского Донца, в результате которого определены концентрации токсичных металлов в водотоках, источники и количество их поступления; (б) проведен мониторинг фармацевтических веществ в природных водах Украины, (в) определены концентрации и основные источники поступления фармацевтических препаратов и удельные показатели потребления различных медикаментов в Харьковском регионе; Усовершенствованы: (а) методика проведения мониторинга воды за счет применения стандартных и инновационных пассивных методов отбора проб воды в контрастных климатических и гидрологических условиях с целью исследования различных форм загрязнителей и их временных вариаций; (б) балансово-статистическая модель, которая позволяет использовать данные мониторинга природных вод для социально-экономической характеристики регионов – водопользователей; Предложены:(а) система определения геохимического фона рек на основании торий – нормализованных концентраций металлов в донных отложениях; (б) метод использование металлов и фармацевтических веществ в качестве индикаторов поступления сточных вод для идентификации несанкционированных сбросов.Основу диссертационного исследования составили натурные данные полевых исследований рек Харькова и Бордо, которые были организованы и проведены с непосредственным участием автора в 2008 – 2011 гг. Большинство лабораторных анализов было лично проведено автором в сертифицированных лабораториях Университета Бордо и Университета Орлеан, Франция.Диссертация имеет теоретическое и практическое значение для дальнейшего развития мониторинга природных вод, а также повышения уровня экологической и социальной безопасности в регионах. По теме опубликовано 4 статьи в международных журналах с высоким ИМПАКТ фактором, а также 5 статей в изданиях, реглиментированных ВАК Украины и России.

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