Ce travail de thèse vise à développer une méthode générale d'évaluation des flux de contaminants issus des ruissellements des matériaux de toiture à l'échelle urbaine. Cette méthode est fondée sur une démarche originale de changement d'échelles intégrant différents outils relevant des sciences de l'ingénieur et des sciences sociales. Le travail comprend la création d'une base de données bibliographique qui permet de disposer d'une vision synoptique des matériaux de toiture nouveaux et anciens utilisés à l'échelle urbaine, ainsi que des contaminants associés. La démarche de changement d'échelle – du toit à l'échelle urbaine – repose sur la notion de situation-type d'émission d'un contaminant par un matériau de toiture à laquelle est associé un flux unitaire unique. Cette notion propose une nouvelle définition de l'émission à l'échelle du toit incluant uniquement les paramètres pertinents à l'échelle urbaine. Afin de faciliter le calcul du flux à l'échelle urbaine, différents principes méthodologiques sont adoptés pour exploiter des bases de données urbaines existantes (base des modes d'occupation du sol, cadastre, images aériennes) et les adapter ou les interpréter au prisme de la problématique particulière des émissions de toitures. Ainsi, les principes de découpage et de croisement sont utilisés pour diviser l'échelle urbaine en entités homogènes. Une entité consiste en un regroupement de bâtiments, caractérisée par une répartition propre de matériaux de toitures. Ces entités sont obtenues en croisant une étude typologique des bâtiments (élaborée à partir de la base des modes d'occupation du sol) avec l'histoire urbaine et avec l'histoire des matériaux de toiture. La définition d'un ensemble de règles empiriques est nécessaire pour permettre la quantification des matériaux des différents éléments de toitures à l'échelle de la ville. Ces règles sont élaborées à partir d'une enquête et d'entretiens menés auprès d'experts des matériaux de toitures (fabricants, syndicats…) ainsi que d'une étude historique et d'une étude du marché des matériaux de toiture.Le développement intégral de la méthode jusqu'au calcul final rend indispensable le choix d'un terrain d'étude et d'un contaminant afin d'en illustrer en détail toutes les étapes de calcul. La ville de Créteil a été choisie car elle présente une mixité urbaine et historique suffisante pour embrasser la plupart des situations urbaines susceptibles d'être rencontrées en France. Elle offre également l'avantage de disposer d'un maximum de situations-types d'émissions renseignées pour le contaminant zinc qui a donc été retenu. Complétant les règles empiriques générales, une méthode statistique est développée sur ce cas d'étude. Croisée à une interprétation visuelle des matériaux de toiture à partir des images aériennes, elle permet d'évaluer la distribution des matériaux de toiture à partir d'un échantillonnage aléatoire simple de bâtiments appliqué à chaque entité homogène de la ville. Le couplage de cette distribution avec les situations-types concernées permet alors une estimation du flux de zinc émis par l'ensemble des toitures de Créteil, à savoir 813 kg.an-1 avec une incertitude de 16,6%.La méthode élaborée est généralisable à d'autres villes et d'autres contaminants. Dans cette optique, la démarche opérationnelle à suivre a été formulée de manière synthétique en fin de travail. Son utilisation peut permettre, d'une part d'évaluer à coût réduit l'impact des toitures d'une métropole ou d'une zone urbanisée sur l'environnement et, d'autre part, d'orienter les pratiques de gestion et l'utilisation des eaux de ruissellement en limitant l'apport de contaminants par les matériaux de toitures. Afin de pouvoir appliquer cette méthode à tout contaminant, des pistes ont été dressées pour définir une approche optimisant l'acquisition de données de flux annuels unitaires pour les différentes situations-types / This thesis aims to develop a general method for modelling roofing materials emissions on the city scale. This method is based on an original scaling approach integrating different tools within the engineering sciences and social sciences. The work includes the creation of a bibliographic database describing new and old roofing materials and their associated contaminants.The scaling approach - from roof to the city scale – is based on a new concept called typical-situation of contaminant emission from roofing material on the roof. For each typical situation a contaminant annual runoff rate is associated. This concept allows the transition between the roof scale and the city scale. To facilitate contaminant flow calculation on the city scale, different methodological principles are adopted to exploit and adapt existing urban databases (land use database, numerical cadastre, and aerial images) with respect to the specific issue of roofing material emissions. Thus, dividing and crossing principles are used to divide the city into homogeneous units. A unit is a cluster of buildings characterized by a specific roofing materials distribution. These units are obtained by crossing a typological buildings study (developed from the land use database) with the city urban history and the roofing material historical evolution. Defining empirical rules is necessary to quantify the distribution of the material in the different roofing elements on the city scale. These rules are developed from a survey made by conducting interviews with experts of the roofing material sector (industrials, masters of work, architects...) as well as a historical study and a market study for roofing materials.The full development of the method makes it essential to choose a study site and a contaminant in order to illustrate in detail all the calculation steps. Créteil city was selected because it presents a big diversity and a large number of buildings in order to represent most of the urban functions of any city in France. In the city of Créteil, zinc annual runoff rates have been produced for different metallic materials for the maximum of zinc typical-situation. A statistical approach was developed to complete empirical rules to compute roofing materials area distribution on the city scale. This approach is based on a stratified random sampling technique in conjunction with aerial images interpretation of the different roofing material element applied for each unit. Given the roofing material distribution and the zinc typical-situations, annual zinc flow from roofing material at Créteil city was estimated namely 813 kg.an-1 with an uncertainty of 16.6%.The developed method can be applied to other cities and other contaminants. In this context, the operational procedure of the application of this method was described at the end of this work. Our method can be used as a decision-making tool by urban planners at three levels to implement policies in order to reduce roofing pollutants emissions. In order to apply this method to any contaminant, different tracks were drawn to define an optimized approach to produce of runoff rates for different typical situations

Cette thèse s'intéresse à la modélisation de la contamination nitrique de la nappe des calcaires de Champigny, ressource stratégique pour l'alimentation en eau potable de l'Île-de-France et pour laquelle plusieurs champs captants ont été identifiés comme prioritaires. Le couplage d'un modèle agronomique STICS et d'un modèle hydrogéologique MODCOU permet de modéliser le transfert des nitrates résultant des pratiques agricoles à travers l'hydrosystème.La mise en place de MODCOU sur la zone d'étude a nécessité d'apporter des modifications au logiciel afin de représenter le fonctionnement de l'hydrosystème comportant des singularités hydrogéologiques. L'application du modèle entre 1971 et 2011 a montré l'importance des échanges nappes-rivières dans le fonctionnement de la nappe et particulièrement sur les bassins d'alimentation des captages (BAC) prioritaires, préalablement identifiés lors d'études antérieures. Pour prendre en compte ces échanges dans la modélisation de la contamination nitrique, un module évaluant les concentrations en rivières par bassin versant a été développé et permet de reproduire l'évolution de la contamination du passé à l'actuel et de réaliser par la suite des scénarios prospectifs.Le développement d'une méthodologie spécifique a permis d'identifier les zones les plus contributives à l'alimentation des captages. Elles se révèlent être situées essentiellement le long des cours d'eaux et représentent un peu moins de la moitié de la superficie des BAC. La mise en rapport des zones d'alimentation principale et de la rapidité du transfert permet de déterminer les zones d'actions prioritaires les plus pertinentes sur lesquelles des mesures de protection pourraient être plus spécifiquement appliquées / This thesis focuses on modelling of the nitrogenous contamination in Champigny's limestone aquifer. This groundwater is a strategic resource for Ile-de-France drinking water supply where several well-fields have been identified as a priority. The coupling of an agronomic model (STICS) and a hydrogeological model (MODCOU) enables to simulate the transfer of nitrates through the hydrosystem resulting from agricultural practices.The implementation of MODCOU on the study area has required improvement of the software for better representing distinctive features of the hydrosystem. The application of this model from 1971 to 2011 shows the importance of exchanges between rivers and aquifers in order to capture aquifer functioning and particularly the behaviour of the well field's water supply basins identified in previous studies. To integrate these exchanges in the modelling of nitrogenous contamination, a module assessing concentrations in rivers has been developed for each catchment and enables to reproduce the evolution of contamination from the past to the present and subsequently realize forward-looking scenarios.The development of a specific methodology enabled to identify the most contributory areas for well-field supply. Results show that these areas are located essentially along streams and represent a little less than half of the area of the well field's water supply basins. The linking between the main recharge area and the transfer velocity enables to determine the most relevant priority action areas on which protective measures could be more specifically applied.

Les mycotoxines sont des métabolites secondaires des moisissures qui peuvent naturellement contaminer de nombreuses denrées alimentaires, notamment les céréales. Dans les travaux de thèse, nous nous sommes intéressés à deux mycotoxines majeures produites par des champignons du genre Fusarium, le Déoxynivalénol (DON) et la Fumonisine (FB). Les objectifs de la thèse ont été de déterminer les effets individuels et combinés d’une contamination en DON et FB chez le porc, une espèce cible et sensible aux mycotoxines. Les effets sur les fonctions immunitaires lors d’un challenge antigénique ainsi que sur les fonctions intestinales ont été évalués. Par ailleurs, dans le cadre d’un partenariat avec un industriel, nous avons évalué in vivo les effets de méthodes de détoxification par biotransformation et ciblant spécifiquement ces deux toxines. Chez le porc, l’ingestion d’aliments contaminés avec de faibles doses de mycotoxines (DON, 3 mg/kg ; FB, 6 mg/kg) a provoqué des lésions tissulaires (foie, reins et poumons) et a fortement altéré la mise en place d’une réponse immunitaire spécifique de l’antigène (expression des cytokines, prolifération des lymphocytes et anticorps spécifiques). Les animaux ont été significativement plus affectés après la consommation du régime co-contaminé, et l’interaction a pu être considérée comme additive. De plus, les paramètres intestinaux examinés ont révélé des changements dans la morphologie, dans le profil de sécrétion des cytokines et dans l’adhésion cellulaire. L’interaction des deux toxines a pu ici être caractérisée comme moins qu’additive. Les approches de détoxification biologique proposées par l’industriel étaient basées sur la transformation par voie enzymatique du DON et des FB, à partir d’un microorganisme entier et d’une enzyme respectivement. La stratégie d’élimination des FB a suscité un intérêt plus important étant donné que cette méthode est non commercialisée et en cours de développement. Ainsi, la toxicité du produit d’hydrolyse de la FB1 (mycotoxine principale de la famille des FB) obtenu initialement par traitement enzymatique, a été comparée in vivo à celle de la molécule mère la FB1. Les résultats ont montré que l’hydrolyse de la FB1 réduisait fortement la toxicité hépatique et intestinale chez les porcelets. L’expérimentation animale avec le DON et la FB, seuls ou en combinaison a ensuite été reproduite afin de déterminer l’efficacité d’hydrolyse de ce procédé chez le porc après incorporation de l’enzyme dans les aliments contaminés. Dans ces aliments, le microorganisme entier ciblant le DON avait également été inclus. La nette diminution du marqueur d’exposition des FB et la neutralisation partielle ou totale des effets ont suggéré que le procédé avait fortement réduit la biodisponibilité des FB dans le tractus gastro-intestinal. Cette observation a aussi été en partie confirmée pour l’approche de dégradation du DON. La biotransformation par voie enzymatique des mycotoxines représente ainsi une stratégie biotechnologique prometteuse dans la lutte contre ces contaminants. / Mycotoxins are secondary metabolites of fungi that are natural contaminants of several commodities, in particular cereals. In the present work, we focused on two major mycotoxins produced by the Fusarium genus, Deoxynivalenol (DON) and Fumonisin (FB). The main objectives of the thesis were to determine the toxic effects of individual and combined DON and FB contamination in pig, a target species highly sensitive to mycotoxins. The effects on the immune functions following an antigenic challenge and also on the intestinal functions were evaluated. Besides, within the framework of an industrial partnership, we evaluated in vivo the effects of detoxifying methods by biotransformation and targeting specifically these two toxins. In pigs, ingestion of contaminated feeds with low doses of mycotoxins (DON, 3 mg/kg ; FB, 6 mg/kg) triggered tissular lesions (liver, kidneys and lungs) and strongly impaired the establishment of the antigenic immune response (cytokines expression, lymphocytes proliferation and specific antibodies). Animals consuming the cocontaminated diet were more affected and the interaction could be considered as additive. In addition, changes in morphology, in profile of cytokines secretion and in cell adhesion were observed at intestinal level. The interaction here could be characterized as less than additive. The biological detoxification approaches proposed by the industrial were based on the transformation by enzymatic way of DON and FB, from intact microorganism and enzyme respectively. We paid a particular attention to the strategy of FB removal as this method is not marketed and still in development. Therefore, the toxicity of the hydrolysis product of FB1 (major mycotoxin in the FB group) initially obtained by enzymatic way, was compared in vivo to the toxicity of the parent compound FB1. Results showed that the hydrolysis of FB1 strongly reduced the toxicity in piglets at intestinal and hepatic levels. The animal experiment with DON and FB, alone or in combination was then repeated in order to determine in pigs the hydrolysis efficiency of this process when enzyme was incorporated in contaminated feeds. In these feeds, the intact microorganism toward DON was also included. The marked decrease of the biomarker of exposure to FB and the partial or total counteraction of the effects suggested that the process had greatly reduced the FB bioavailability in the gastrointestinal tract. This observation was also in part confirmed for the method degrading DON. The biotransformation method of mycotoxins by enzymatic way represents therefore a promising biotechnological strategy in the control of these contaminants.

Não consta resumo na publicação. / Abstract not available.

Cette thèse a pour objet l'étude des éléments radioactifs qui peuvent altérer le bon fonctionnement des composants électroniques au niveau terrestre. Ces éléments radioactifs sont appelés émetteurs alpha. Intrinsèques aux composants électroniques, ils se désintègrent et émettent des particules alpha qui ionisent la matière du dispositif électronique et déclenchent des SEU (Single Event Upset). Ces travaux visent à évaluer la fiabilité des circuits digitaux due à cette contrainte radiative interne aux composants électroniques. Dans ce but, tous les émetteurs alpha naturelles ou artificielles susceptibles de contaminer les matériaux des circuits digitaux ont été identifiés et classés en deux catégories : les impuretés naturelles et les radionucléides introduits. Les impuretés naturelles proviennent d'une contamination naturelle ou involontaire des matériaux utilisés. Afin d'évaluer leurs effets sur la fiabilité, le SER (Soft Error Rate) a été déterminé par simulations Monte-Carlo pour différents nœuds technologiques dans le cas de l'équilibre séculaire. Par ailleurs, avec la miniaturisation des circuits digitaux, de nouveaux éléments chimiques ont été suggérés ou employés dans la nanoélectronique. Les radionucléides introduits regroupent ce type d'élément naturellement constitué d'émetteurs alpha. Des études basées sur des simulations Monte-Carlo et des applications analytiques ont été effectués pour évaluer la fiabilité des dispositifs électroniques. Par la suite, des recommandations ont été proposées sur l'emploi de nouveaux éléments chimiques dans la nanotechnologie. / This work studies radioactive elements that can affect the proper functioning of electronic components at ground level. These radioactive elements are called alpha emitters. Intrinsic to electronic components, they decay and emit alpha particles which ionize the material of the electronic device and trigger SEU (Single Event Upset).This thesis aims to assess the reliability of digital circuits due to this internal radiative constraint of electronic components. For that, all alpha-emitting natural or artificial isotopes that can contaminate digital circuits have been identified and classified into two categories: natural impurities and introduced radionuclides.Natural impurities result from a natural or accidental contamination of materials used in nanotechnology. To assess their effects on reliability, the SER (Soft Error Rate) was determined by Monte Carlo simulations for different technology nodes in the case of secular equilibrium. Besides, a new analytical approach was developed to determine the consequences of secular disequilibrium on the reliability of digital circuits.Moreover, with the miniaturization of digital circuits, new chemical elements have been suggested or used in nanoelectronics. The introduced radionuclides include this type of element consisting of natural alpha emitters. Studies based on Monte Carlo simulations and analytical approches have been conducted to evaluate the reliability of electronic devices. Subsequently, recommendations were proposed on the use of new chemical elements in nanotechnology.

La contamination par les hydrocarbures peut altérer les propriétés physicochimiques et biologiques du sous-sol, par conséquent le diagnostic et l’évolution des contaminants peuvent être surveillés en couplant les analyses géochimiques et les techniques géophysiques. Dans ce travail, différentes méthodes géophysiques de sub-surface telles que la tomographie de résistivité électrique, la polarisation induite, le géoradar et le potentiel spontané ont été utilisées d’une manière combinée pour localiser les zones impactées par les hydrocarbures du site de l’ancienne raffinerie de Petit Couronne. Les investigations géophysiques par la tomographie de résistivité électrique en 2D ont révélés la présence des anomalies de fortes valeurs de conductivité et chargeabilité électrique associés aux zones contaminées de l’aquifère. Les résultats obtenus avec les profils d’ERT et IP indiquent que la contamination a modifié les parties capacitives et ohmiques de la conduction électrique dans les sédiments contaminés. Cette signature très conductrice des zones contaminées est due aux processus de biodégradation des hydrocarbures qui minéralisent les eaux de l’aquifère. Les panaches d’hydrocarbures ont été identifiés sur les profils de géoradar par une forte atténuation des amplitudes de signaux électromagnétiques. Les profils de potentiel spontané ont aussi fourni une cartographie spatiale des zones contaminées par leurs signatures électriques négatives qui est associées aux processus d'oxydoréduction et biodégradation à l’interface entre la zone non saturée et saturée. Une carte de potentiel redox a été reconstruite à partir de l'inversion des données résiduelles de potentiel spontané grâce au calcul des composantes de la densité du courant électrique. La contribution redox dans l'aquifère contaminé s'explique par des dipôles verticaux répartis sur la frange capillaire juste au-dessus de la nappe phréatique, en favorisant le mécanisme de la biogéobatterie sur ce site. L’ensemble de ces résultats ont été confirmés par les mesures géochimiques menées au niveau des forages. L'étude a montré que les altérations biologiques des hydrocarbures ont modifié les propriétés chimiques de l'eau porale et que l'étendue de la contamination des eaux souterraines peut être délimitée à partir du contraste géophysique observé entre les zones contaminées et les zones non contaminées. La combinaison des différentes méthodes géophysiques avec des analyses géochimiques ponctuelles au niveau des forages ont permis de mieux comprendre les différents processus qui sont à l’origine de modifications des propriétés biogéochimiques dans les sols et les eaux souterraines. / The presence of hydrocarbon contamination in the subsurface can modify the physiochemical and biological properties of soil and groundwater. The sensitivity of geophysical methods to biogeochemical changes occurring in contaminated media can be used to monitor hydrocarbon contamination in a fast and inexpensive way. As such, geophysical methods including, electrical resistivity tomography, induced polarization, ground penetrating radar, self-potential and magnetic susceptibility were used in this work to characterize the hydrocarbon contamination and investigate its effects on the soil and groundwater geophysical and geochemical properties at a site impacted by an aged hydrocarbon plume. The geophysical response to hydrocarbon contamination varies according to factors related to the contaminant in question and to the contaminated environment. Therefore, to achieve a better interpretation, the field geophysical data were constrained by geochemical soil boring data which showed that biodegradation is occurring in the site. This was shown through observing elevated total dissolved solids concentrations, elevated groundwater electrical conductivity values, negative redox potential values and depleted terminal electron acceptors concentrations in the contaminated locations. Throughout the investigation, the geophysical measurements supported the conductive model and consistently recorded low resistivity anomalies, high chargeability values and attenuated GPR reflections in the contaminated zones. Additionally, significant negative self-potential anomalies associated with oxidation-reduction processes coupled to the biodegradation of hydrocarbons were recorded in the groundwater contaminated zone. Based on this observation, a redox potential map of the contaminated site was constructed by the inversion of the field self potential data. Throughout the process, a groundwater model was first calibrated to remove the electrokinetic component from the SP signal. Then, the obtained residual self potential data was inverted for the electrical current density by using an inversion algorithm which includes minimizing a cost function with a data misfit contribution and a regularizer. As a result, the obtained current density was used to construct a map of redox potential showing the borders and the redox front of the contaminant plume. The redox contribution was explained by vertical dipoles distributed across the capillary fringe, supporting further the mechanism of bio-geo-battery which was created due to the existence of a strong redox potential gradient between the highly reducing conditions within the plume and the oxidizing conditions outside the plume. Furthermore, elevated magnetic susceptibility values were recorded in the biologically active transition zone where bio-precipitation of iron minerals is occurring. Given these results, this study showed that biological alterations of hydrocarbons induced subtle changes in the pore water biogeochemistry, which consequently modified the geophysical properties of the contaminated sediments. The extent of groundwater contamination was delineated according to the geophysical contrast between the contaminated and clean zones. Moreover, the combination of the different geophysical methods, constrained by the geochemical point measurements, provided insight on the different processes which might have modified the soil and groundwater biogeochemical properties at the contaminated site.

<p>U okviru ovog istraživanja ispitani su: (1) Procesi koji se odvijaju prilikom &nbsp;bioremedijacije zemlji&scaron;ta zagađenog naftom i derivatima nafte, koje je bilo izloženo&nbsp;spontanim abiotičkim i biotičkim procesima degradacije u toku 8 godina, tehnikama&nbsp;biogomila i povr&scaron;inske obrade na poluindustrijskoj (pilot) skali uz optimizaciju&nbsp;tehnolo&scaron;kih parametara sa ciljem povećanja efikasnosti i efektivnosti biodegradacije&nbsp;ugljovodonika; (2) Uticaj starenja, koncentracije, biodsotupnosti i strukture zagađujućih&nbsp;materija na procese biodegradacije i biotransformacije u kontrolisanim laboratorijskim&nbsp;uslovima. Tokom dve godine bioremedijacionog tretmana sadržaj mineralnih ulja opao&nbsp;je za 52% (od 27,8 g/kg do 13,2 g/kg) i 53% (od &nbsp;23,2 g/kg do 10,8 g/kg), dok je sadržaj&nbsp;ukupnih ugljovodonika opao za 43% (od 41,4 g/kg do 23,4 g/kg) i 27% (od 35,3 g/kg do&nbsp;25,8 g/kg) u biogomili i povr&scaron;inskoj obradi respektivno. Efikasnost uklanjanja&nbsp;mineralnih ulja iz zemlji&scaron;ta u dva posmatrana bioremedijaciona tretmana je praktično&nbsp;ista. Međutim, u pogledu sadržaja ukupnih ugljovodonika u biogomili uklonjeno je dva&nbsp;puta vi&scaron;e ukupnih ugljovodonika (gledajući &nbsp;apsolutnu količinu ukupno uklonjenih&nbsp;ugljovodonika). Kinetika biodegradacije mineralnih ulja i ukupnih ugljovodonika u toku&nbsp;tretmana u biogomili u saglasnosti je sa kinetičkim modelima lnC=lnC_0-kt i lnC=lnC_0-kt^0,5. Kinetika biodegradacije mineralnih ulja u toku povr&scaron;inske obrade relativno se&nbsp;dobro može opisati sa dva pomenuta kinetička modela, međutim, znatno bolju&nbsp;korelaciju pokazao je linearni model (C=C_0-kt) primenjen na prvih 92 i poslednjih 200&nbsp;dana eksperimenta. Promena sadržaja ukupnih ugljovodonika u toku povr&scaron;inske obrade&nbsp;zagađenog zemlji&scaron;ta relativno je u dobroj korelaciji samo sa kinetičkim modelom&nbsp;lnC=lnC_0-kt^0,5. Laboratorijska ispitivanja pokazala su da biodegradabilnost i sudbina&nbsp;ugljovodonika u životnoj sredini jako zavise od tipa, starosti i koncentracije zagađujućih&nbsp;materija. Naime, u slučaju zemlji&scaron;ta sveže kontaminiranog dizel uljem, već pri&nbsp;<br />koncentracijama od 20 mg/g uočen toksičan efekat koji je prevaziđen nakon dve nedelje&nbsp;tretmana kao posledica smenjenja prekomerne koncentracije rastvorenih ugljovodonika&nbsp;biotičkim i abiotičkim putem i adaptacije prisutne mikroflore. U slučaju većih&nbsp;koncentracija ovaj efekat je bio jo&scaron; izraženiji. Kod zemlji&scaron;ta kontaminiranog sirovom&nbsp;naftom isti efekat se javlja tek pri koncentraciji od 35 mg/g, kao posledica toga da&nbsp;sirova nafta sadrži manju količinu lako rastvornih ugljovodonika. Za razliku od sveže&nbsp;kontaminiranog zemlji&scaron;ta, na biodegradaciju starog naftnog zagađanja u zemlji&scaron;tu&nbsp;koncentracija nije imala uticaj, u ovakvom zemlji&scaron;tu respiracija je bila na veoma niskom&nbsp;nivou pri svim ispitivanim koncentracijama, ali ne kao posledica toksičnosti, već kao&nbsp;posledica činjenice da se degradabilni deo zagađujućih materija degradirao tokom&nbsp;procesa starenja, tako da su u zemlji&scaron;tu zaostali visokomolekularni &nbsp;te&scaron;ko rastvorni&nbsp;ugljovodonici (smole, asfaltne komponente i dr.) sekvestrovani u zemlji&scaron;tu. Merenja biodostupnosti ugljovodonika (ekstrakcijom sa Tween80) pokazala &nbsp;su da je u zemlji&scaron;tu sveže kontaminiranom dizel uljem i sirovom naftom i starim naftnim zagađenjem oko 95%, 85% i 40% ugljovodonika biodostupno, respektivno. Koncentracija rezidualne frakcije mineralnih ulja i ukupnih ugljovodonika dobijena nakon 48 dana laboratorijskog tretmana u skoro svim probama je veća od predviđenih, &scaron;to je posledica bifaznog pona&scaron;anja ugljovodonika u zemlji&scaron;tu, gde se jedan deo uklanja biodegradacijom, dok drugi deo difunduje u pore zemlji&scaron;ta i kompleksira se sa zemlji&scaron;nom organskom materijom. Količina ugljovodonika iz starog naftnog zagađenja zemlji&scaron;ta koja može da pređe u vodenu fazu je mala reda veličine nekoliko mg/l, međutim, u prirodnim uslovima usled spiranja ugljovodonika sa zemlji&scaron;ta ki&scaron;om, postoji verovatnoća da ovi ugljovodonici dospeju u podzemnu vodu iznad maksimalno dozvoljene koncentracije za vodu za piće (MDK = 10 &mu;g/l) i na taj način degradiraju njen kvalitet. Zbog nemogućnosti daljag uklanjanja zagađenja bioremedijacijom, preostala količina zagađujućih materija koja može dospeti u vodenu fazu bi trebalo da se ukloni nekim drugim remedijacionim tehnikama pre njegovog konačnog bezbednog odlaganja u životnu sredinu.</p> / <p>The aims of this study were to examine: (1) the processes that occur during bioremediation of soil contaminated by oil and oil derivatives, which was exposed to spontaneous abiotic and biotic degradation processes over 8 years, using pilot scale biopiles and landfarming techniques to optimise technological parameters with the aim of increasing the efficiency and effectiveness of hydrocarbons biodegradation. (2) the effect of contaminants weathering, concentration, bioavailability and structure on the biodegradation and biotransformation process under controlled laboratory conditions. Over the two years of bioremediation treatment by biopiles and landfarming, the mineral oil content decreased by 52% (from 27.8 g/kg to 13.2 g/kg) and 53% (from 23.2 g/kg to 10.8 g/kg),&nbsp; and the total hydrocarbon content decreased by 43% (from 41.4 g/kg to 23.4 g/kg) and 27% (from 35.3 g/kg to 25.8 g/kg), respectively. The efficiency of mineral oil removal from soil in these two applied bioremediation treatments was practically the same. However, in terms ofthe absolute amount of total hydrocarbons, twice as many total hydrocarbons were removed in the biopile. The mineral oil and total hydrocarbons biodegradation kinetics in the biopile were in good agreement with&nbsp; the kinetic models lnC = lnC0-kt and lnC = lnC0-kt0.5. The mineral oil biodegradation&nbsp;kinetics during the landfarming treatment is relatively well described with those two kinetic models, however, significantly better correlation is obtained by the linear model (C = C0-kt) applied to the first 92 and last 200 days of the experiment. The change in total hydrocarbons content during the landfarming treatment is in relatively good correlation only with the kinetic model lnC = lnC-kt0.5. The laboratory biodegradation investigation showed that hydrocarbon biodegradability and its fate in the environment strongly depend upon the structure, concentration and weathering of the hydrocarbons. Thus, in the case of diesel contaminated soil, as a consequence of&nbsp; its structure, i.e. the presence in a higher concentration of the soluble and toxic midrange n-alkanes, a toxic effect is detected at a diesel oil concentration of 20 mg/g, although this effect is overcome after two weeks, as a consequence of the decreasing&nbsp; concentration of soluble hydrocarbons in biotic and abiotic processes and microbial adaptation. This effect was more pronounced in the case of the soil withthe highest diesel oil concentration. In crude oil contaminated soil, a toxic effect was observed at a much higher hydrocarbon concentration (35 mg/g) than in the diesel oil contaminated soil, which corresponds to the fact that crude oil contains significantly less soluble hydrocarbon. In contrast to these two freshly contaminated soils, the weathered contaminated soil contaminant concentration did not have an effect on hydrocarbon biodegradation, with biodegradation in this soil actually at a low level at all concentrations, not as a consequence of toxicity, but because the degradable part of the contaminant was already degraded during the weathering process, leaving behind only highly condensed hydrophobic organic contaminants (asphaltenes, resins, etc.) sequestered in the soil. The data obtained for hydrocarbons bioavailability (by Tween80 extraction) showed that the bioavailable hydrocarbon fraction from soils freshly contaminated with diesel oil and crude and weathered oil contamination were approximately 95%, 85% and 40%, respectively. The concentration of residual mineral oil fractions and total hydrocarbons obtained after 48 days of laboratory biodegradability treatment in almost all batches was greater than predicted, as a result of the biphasic behaviour of hydrocarbons in the soil, where some were degraded or lost from the soil and some transformed into the recalcitrant fraction. The amount of hydrocarbons from the weathered soil contamination that can be transferred into the water phase is small, of the order of a few mg/l in magnitude, however, under natural conditions, due to hydrocarbons leaching by rainfall, it is possible that these hydrocarbons infiltrate groundwater above&nbsp; the maximum permissible concentration for drinking water (MAC = 10 &mu;g/l) and thus degrade its quality. As it is not possible to achieve further contamination degradation by bioremediation, the remaining amount of pollutants which can be transferred into the water phase should be removed by some other remediation techniques before its final safe disposal in the environment.</p>

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Text in English / Fungal species and their mycotoxins are the most predorminant contaminants of dried agricultural products in sub-Saharan Africa (SSA) and the main species of fungi that can synthesize mycotoxins are Aspergillus, Fusarium and Penicillium. In Africa, aflatoxin is labelled as a great threat to human and animal health due to its high contamination levels reported of aflatoxins in foods. The aim of this study was to survey fungi and aflatoxin contamination of small-scale processed foodstuffs sold at informal retail outlets in the Johannesburg metropolis, South Africa. A total of 270 food samples (10 starch and legume based foods, 11 meat and fish based foods, 22 spices and local condiments, 14 dried fruits and vegetables) were collected from retailers; and analysed four (4) times in different seasons of spring, summer, autumn and winter. Out of the 270 samples analysed, only 27.8% were contaminated with fungal. Of all the six categories of foods analysed, roots and tubers (60.0%), nuts and seeds (40.0%), dried vegetables (37.1%), and the Meat and Insect foods (33.3%) respectively, had the most contaminated samples with fungal respectively. The least contaminated food groups were the fish foods (10.0%) and spices and local condiments (16.7%) respectively. Twenty percent of the 270 dried food analysed were contaminated by Aspergillus species out of which 61.1% of the contaminated samples had fungal counts above 103 cfu/g. Aspergillus niger was the most predominant Aspergillus species identified in all the categories of food samples analysed. Fruits and vegetables (24.4%) and the nuts and seeds (20.0%) food groups had the highest number of samples contaminated with aflatoxin. Peanut flour and Cardamom had the most incidence of aflatoxin. AFB1, AFB2 & AFG1 were the most prominent aflatoxin types recovered from the food samples. Almost all the food samples in which aflatoxin were identified had aflatoxin values above 10μg/ml. / Life and Consumer Sciences / M.Sc. (Life Science)

The newly planned lead recycling zone in Dong Mai village has been operating with primary treatment systems using lime to neutralize acid in wastewater is a good sign for the local environment, yet the real problem that needs further attention and proper solutions is the accumulation of heavy metals typically lead (Pb) and cadmium (Cd) in agricultural land near the old Pb recycling area. In this context, 27 soil samples were collected and analyzed by AAS method to assess the situation and the quality of the agricultural soil. The results showed that the levels of Cd in the soil were still in acceptable level according to National Regulation. However, the lead contents in all of the soil samples exceeded National Regulation. The level of Pb pollution in soil was inversely proportional to the distance with old lead melting zone. The lead content in the soil sample collected at the distance of 50 m radius to the old melting zone reached 7070 ppm, which was 100 times higher than the allowable value of National Regulation. / Khu tái chế chì mới tại thôn Đông Mai đã được quy hoạch và đi vào hoạt động cùng hệ thống xử lý sơ bộ với vôi bột là một tín hiệu đáng mừng cho môi trường nơi đây, nhưng vấn đề cần quan tâm và giải quyết triệt để là sự tích lũy một lượng lớn kim loại nặng điển hình là chì (Pb) và cađimi (Cd) trong đất nông nghiệp gần những khu tái chế chì cũ. 27 mẫu đất đã được thu thập và phân tích bằng phương pháp AAS để đánh giá tình trạng, chất lượng đất nông nghiệp tại đây. Kết quả cho thấy hàm lượng Cd trong đất vẫn trong mức độ cho phép theo Quy chuẩn quốc gia. Tuy nhiên, 100% các mẫu đất đều có hàm lượng chì vượt quá mức cho phép theo Quy chuẩn quốc gia. Mức độ ô nhiễm Pb trong đất tỷ lệ nghịch với khoảng cách tới khu lò nấu chì cũ. Mẫu đất cách 50 m so với khu vực lò cũ có hàm lượng chì lên tới 7070 ppm, gấp hơn 100 lần so với Quy chuẩn quốc gia.