Les industries de traitement du phosphate dans le but de produire des engrais phosphatés, très présentes dans la zone côtière sud du Grand Sfax en Tunisie, sont à l’origine d’émissions atmosphériques et de rejets de déchets ; en l’occurrence du phosphogypse chargés de contaminants métalliques. La contamination des sols qui en résulte est une contamination persistante. Dans le but de mieux comprendre les effets de la contamination par les métaux engendrés par cette activité industrielle, une attention particulière a été portée sur une espèce d’importance économique, le palmier dattier Phoenix dactylifera. Le présent travail avait pour objectifs d'étudier la germination des graines et la variété Deglet Nour dans différents contextes de contamination métallique aux moyens de techniques de biotechnologie végétale impliquant la recherche in silico et la culture in vitro de vitroplant et à l’aide de deux approches. Une approche individuelle intégrative qui s’est servie de nombreuses mesures de biomarqueurs morphologiques et biochimiques chez l’espèce étudiée exposée à divers stress métalliques. Une deuxième approche, plus moléculaire et mécanistique avait pour but d’identifier des gènes qui répondent à une exposition au Cd, ou au Cu, ou au Cr capables de prédire les voies métaboliques impliquées. Cette seconde approche, basée sur l’exploitation d’une banque de cDNA de la variété Deglet Nour a permis l’identification de gènes de chélateurs et transporteurs de métaux. Le suivi des niveaux d’expression de ces gènes chez des plantes placées dans des conditions d’expositions métalliques variées a permis de mieux comprendre les mécanismes de détoxication des métaux mis en œuvre. / The phosphate processing industries for the production of phosphate fertilizers, which are present in the southern coastal zone of the Grand Sfax in Tunisia, caused atmospheric emissions and waste discharges i.e., phosphogypsum loaded with metal contaminants. The resulting contamination of soils is a persistent contamination. In order to better understand the effects of metal contamination caused by this industrial activity and ultimately to propose measures for the rehabilitation and/or ecological restoration of the sites but also because of its economic importance, particular attention has been paid on the palm date (Phoenix dactylifera). The aim of this work was to study seed germination and growth of the Deglet Nour variety in various metal contamination contexts by means of plant biotechnology techniques involving in silico research and in vitro culture of vitroplant. Two approaches have been performed. An individual integrative approach that used numerous measurements of morphological and biochemical biomarkers in date palm exposed to various metal stresses. A second approach, more molecular and mechanistic, was performed to identify genes that respond when plants are exposed to Cd, Cu, or Cr which help for the prediction of the metabolic pathways that are affected by contaminants or involved in detoxification processes. This second approach, based on the exploitation of a cDNA library of the Deglet Nour variety, allowed the identification of genes coding for metal chelators and transporters. Monitoring of the levels of expression of these genes made it possible to better understand the detoxification mechanisms of metals in the palm date.

No description available.

Petroleum hydrocarbons are the most widespread contaminants in the environment. Interest in the biodegradation of polycyclic aromatic hydrocarbons and compounds (PAHs/PACs) is motivated by their ubiquitous distribution, their low bioavailability, high persistence in soils and their potentially deleterious effects to human health. Identifying the diversity of microorganisms that degrade PAHs/PACs can be utilised in the development of bioremediation techniques. Understanding the mechanisms of bacterial populations to adapt to the presence of pollutants and the extent that lateral transfer of key functional genes occurs, will allow the exploitation of microbial PAC/PAH-degradative capabilities and therefore enhance the successful application of bioremediation strategies. A key aim of this study was to isolate and identify PAC-degrading bacteria for potential use in future bioremediation programmes. A series of PAC enrichments were established under the same experimental conditions from a single sediment sample taken from a highly polluted estuarine site. Distinct microbial community shifts were directly attributable to enrichment with different PAC substrates. The findings of this study demonstrate that five divisions of the Proteobacteria and Actinobacteria can degrade PACs. By determining the precise identity of the PAC-degrading bacteria isolated, and by comparing these with previously published research, this study showed how bacteria with similar PAC degrading capabilities and 16S rRNA signatures are found in similarly polluted environments in geographically very distant locations e.g. China, Italy, Japan and Hawaii. Such a finding suggests that geographical barriers do not limit the distribution of key PAC-degrading bacteria. This is significant when considering the diversity and global distribution of microbes with PAC-degradative capabilities and the potential for utilising these microbial populations in future bioremediation strategies. In the laboratory, enrichment of bacteria able to utilise PAHs has commonly been performed in liquid media, with the PAH dissolved in a carrier solvent. This study found the presence of a carrier solvent significantly affects the resultant microbial population. Although the same sediment sample was used as the bacterial source in all enrichments, different bacterial strains were obtained depending upon the presence of the carrier solvent and the PAH. This is important when considering appropriate methodology for the isolation of PAH-degrading bacteria for future bioremediation programmes. Additionally, the species comprising the resultant population of the enrichment when a carrier solvent was present were similar to previously reported PAH-degrading species. Such a finding necessitates review of previously reported PAH-degrading bacterial species that have been isolated and identified from enrichments using a carrier solvent. Understanding how bacteria acclimatise to environmental pollutants is vital for exploiting these mechanisms within clear up strategies of contaminated sites. Two major lineages of the α subunit of PAH dioxygenases were identified: Actinobacteria and Proteobacteria. Comparison of the α subunit phylogeny with the 16S rRNA phylogeny implies that the PAH-dioxygenases evolved prior to the separation of these phyla or that lateral transfer occurred in the very distant past. No evidence for lateral transfer of the α subunit between the Actinobacteria and Proteobacteria was found in the phylogenetic analyses of this research. Multiple lateral transfer events were inferred between the species of the Actinobacteria and between the classes of the Proteobacteria. The clustering of the taxa within the α subunit phylogeny indicates that lateral transfer of the α subunit gene occurred after the separation of the classes of Proteobacteria and also after the speciation of the γ-Proteobacteria. These findings reveal how bacteria have acclimatised to PAH pollutants through multiple lateral transfer events of a key PAH-degradative gene. This knowledge of the transfer of genetic material will broaden our prospects of exploiting microbial populations.

There is significant concern about the accumulation of potentially toxic elements (PTEs) in soils because of both direct and indirect impacts on human and ecosystem health. Knowledge of the fate and distribution of such contamination can lead to an effective assessment of the hazards to soil biota and the need for protective or mitigation activities. This is a particular challenge due to the heterogeneity of the soil matrix and complexity of the processes that determine PTE availability to soil biota. While whole-cell bacterial biosensors have been proposed as tools in enabling greater confidence in addressing such biological and chemical interfaces their genuine value remains to be realised. The underpinning objective of this work was to link the response of microbial biosensors to detailed chemical analysis and to relate the dose response sensitivity to other biological measurements. To better understand the phenomena of PTE bioavailability, the study considered changes in toxicity within the context of ion competition in both freshly amended and historically impacted soils. The interaction of test bacteria with both free (soil pore water) and sorbed (solid phase) fractions of the target analytes (copper, nickel and zinc) has enabled a better estimation of bioavailability/toxicity of PTEs in soils. In comparison to other assays, the responses of the microbial sensor to Cu, Ni and Zn highlighted its relative sensitivity to PTE contamination. The use of luminescence marked microbial sensors complements the performance of rigorous analytical soil chemistry approaches. Their value in soil pollution should be considered a technique that should be interpreted alongside chemical analysis rather than an alternative as their performance in complex environmental matrixes is yet to be validated.

This thesis reports the design and development of the first waveguide surface plasmon resonance (SPR) biosensor for pesticide analysis. The integrated optical format allows the fabrication of a compact sensor that may be connected to optical fibre; necessary steps towards a portable optical biosensor. A major advantage of the integrated optical approach is the possibility of fabricating multiple sensors on one substrate, and hence testing for multiple analytes in one basic assay. The SPR structure incorporates a metal film that may be employed as an electrode to study the electrochemical control of sensing reactions. The performance of such devices requires analysis of the waveguide modes supported by the metal-clad waveguide, of their excitation by an input waveguide and of the resultant power coupled into an output waveguide. For the first time a rigorous numerical waveguide model to study the power transmission of such general multilayer absorbing structures has been developed. The model allows the determination of the modulation in output power of the sensor due to the adsorption of a thin organic layer to the sensor surface, which in turn leads to a measure of sensitivity. Designs for practical, sensitive, waveguide SPR sensors for an aqueous environment, optimised for specific sensing films are reported. The fabrication of gold-coated, potassium ion-exchanged, waveguide SPR sensors in soda-lime and Pyrex glass is reported. Three types of experiment were performed to validate the waveguide model using these devices. The first involved measuring changes in the output power of the sensor as a function of gold film length. The second measured the SPR response of sensors as a function of gold film parameters. Third, the effect on the SPR response of binding a dual layer of biotin-avidin to the sensor surface was observed as a function of gold film thickness. Predictions of the waveguide model were compared to the experimental data. Optimisation of the sensor design through these experimental procedures is also described. The transformation of the basic waveguide SPR sensor into a specific biosensor for the triazine herbicides simazine and atrazine is reported. The assay procedure was based on anti-simazine and anti-atrazine IgG antibodies and their Fab fragments developed by co-workers at GEC Marconi Materials Technology Ltd., UK Chemical modification of the sensor surface was developed by co-workers at the University of Tubingen, Germany, to bind the antibodies to the sensor surface. Laboratory characterisation of the sensor as a simazine sensor was performed and is reported in this thesis. Extended validation identified a detection limit of 0.22µg/l for the herbicide simazine in the aqueous environment. The biosensor gave a significant correlation with HPLC measurements on natural water samples when the cross-reactivity of the sensor with other triazine herbicides was taken into account.

Orientador : Alberto Pio Fiori / Co-orientador : Andre Virmond Bittencourt / DissertaçãO (mestrado) - Universidade Federal do Paraná / Resumo: A malha urbana configurada pela grande Curitiba tem limites praticamente coincidentes com a distribuição geográfica dos sedimentos da Bacia de Curitiba. A inexistência de informações sobre o lançamento de efluentes industriais no meio, alarma e reclama no mínimo urgência por estudos de compatibilidade entre lixívias e materiais gue compõem a Bacia de Curitiba: sedimentos pleistocênicos da Formação Guabirotuba e depósitos aluvionares holocênicos. Em sua parte teórica, este trabalho ocupa-se das variáveis relacionadas à interação solo-solução contaminante, explorando sobretudo as propriedades dos argilominerais como constituintes do solo que desempenham importante papel na dinâmica de trocas de cátions. O estudo aplicado centra atenção na caracterização geotécnica e físico-química de solos residuais da Formação Guabirotuba. explorando técnicas laboratoriais consagradas, com adequação aos chamados "ensaios de compatibilidade". O emprego de soluções fortemente enriquecidas em elementos pesados (Cu e Zn), simulando padrões de emissões industriais, permitiu a observação de importantes efeitos no comportamento geotécnico das amostras ensaiadas. Ensaios de adsorção via Batch Tests, realizados com amostras de solo residual da Formação Guabirotuba e soluções aquosas enriquecidas em elementos pesados, revelaram resultados muito interessantes, que em essência refletem a aptidão eletroquímica dos constituintes minerais presentes, atribuindo-se sobretudo à esmectita cólcica e aos carbonatos, a responsabilidade pela imobilização dos metais pesados. Os resultados foram objeto de tratamento matemático (regressão linear por transformação), visando a definição dos parâmetros Kd, N e R2. Ensaios de tamponamento, simples rotinas de titulação, traduziram a capacidade do material da Formação Guabirotuba resistir ao incremento de condições ácidas, evidenciando sua superior performance em relação à amostra caulinítica também tratada. / Abstract: The urban mesh configured by the greater Curitiba region has its limits practically coincident with the geographical distribution of the sediments of the Curitiba Basin. The lack of information about the volumes of industrial wastes released on the environment, alarms and urges for at least compatibility studies among wastes and materials that compose the Basin of Curitiba: pleistocenics sediments of the Guabirotuba Formation and holocenics deposits. In its theoretical part, this work is in charge of the variables related to the soilpolluting solutions interaction, exploring the properties of the clays-minerals that play important role in the cation's exchange dynamics. The applied study focuses on the geotechnical and physical-chemistry characterization of residual soils in the Guabirotuba Formation, exploring widely known laboratorial techniques, whose adaptation to the called "compatibility rehearsals", employing solutions strongly enriched in heavy elements (Cu and Zn), simulating patterns of industrial emissions, has allowed the observation of important effects in the geotechnical behavior of the rehearsed samples. Rehearsals of adsorption through Batch Tests, done with samples of residual soil from the Guabirotuba Formation and aqueous solutions enriched in heavy elements, have revealed very interesting results, that in essence reflect the electrochemical aptitude of present representative minerals, attributing above all to the calcic esmectite and the carbonates, the responsibility :or the immobilization of heavy metals. The results were object of mathematical treatment (linear regression by transformation), in order to define the parameters Kd, N and R2. Buffer capacity rehearsal, a simple titration routine, reveals the capacity of Guabirotuba Formation's material to resist to the increment of acid conditions, also evidencing its superior performance in relation to the treated caulinitic sample.

La compréhension du transfert des polluants et leurs mobilités dans les sols permet une meilleure approche des risques environnementaux. Elle nécessite une bonne caractérisation du substrat recevant le polluant, la connaissance de l’état de spéciation du polluant et des mécanismes de rétention mis en place : sorption, précipitation, complexation. Les mécanismes de transfert de l’arsenic (As) et du chrome (Cr) sur un substrat naturel sont étudiés dans le cadre de cette thèse. Le substrat, issu de la formation géologique de Gault, est composé majoritairement de quartz, mica et d’argile (Illite, Smectite, Kaolinite) avec la présence d’oxyde de fer sous forme de goethite. La méthodologie expérimentale repose sur une gamme de tests variée de type batch de sorption/désorption, DGT (Diffusif Gradient in Thin film), extractions séquentielles, colonnes. Un modèle géochimique de complexation de surface (MCS) est également mis en place pour approfondir la compréhension de la sorption d’As et du Cr. Les résultats montrent une rétention importante d’As (V) via des mécanismes de sorptions spécifiques sur les argiles et les oxydes de fer du substrat ainsi qu’une forte sensibilité de la sorption à la présence de phosphates dans le milieu. La sorption de Cr (VI) sur le substrat est faible. La rétention de Cr est donc soumise au processus de réduction de Cr (VI) en Cr (III), Cr (III) étant thermodynamiquement stable sous forme précipité dans une large gamme de pH-Eh. L’utilisation du MCS comme outil prédictif nécessite la levée de certains freins, liés aux systèmes complexes, mais permet de confirmer les hypothèses émissent à partir des résultats expérimentaux. / The understanding of the transfer of pollutants from solution to soil and their mobility improve environmental risks assessment. A detailed substrate characterization, good knowledge of speciation state and mechanisms of retention (sorption, precipitation, complexation) is necessary. Transfer mechanisms of arsenic (As) and chromium (Cr) on a natural substrate are studied in this thesis. The substrate,extracted from the Gault geological formation, is mainly composed of quartz, mica and clay (illite, smectite, kaolinite) and we noted a little part of iron oxide as goethite. The experimental methodology is based on a wide range of test: sorption and desorption batch, DGT (diffusive gradient in Thin Film), sequential extractions, columns. A geochemical model surface complexation (MSC) is constructed to access of the speciation of As and Cr on aqueous and solid phase. The results show a significant retention of As (V) on clay and goethite with specific sorption and a high sensitivity of As sorption in presence of phosphate. Sorption of Cr (VI) on the substrate is low. Retention of Cr depends on the reduction process of Cr (VI) to Cr (III), whose precipitates are thermodynamically stables on a wide range of pH-Eh. Use of MSC as a predictive tool requires further investigation but MCS can confirms the assumptions from experimental results.

Mining industry has been identified as the main sustenance of the South African economy, however the negative impacts of the industry on the ecological systems cannot be over emphasized due to the released waste which is mostly heavy metals into the environment. The study evaluated six heavy metal (A1, Cu, Fe, Ni, Pb and Cr) contents in a tailings dam from a specific mine site. Two sets of samples for the investigation were measured, that is, one in year 2012 and the other in year 2013. In the year 2012, the sample set was only taken at a distance profile of 500 meters from the foot of the dam, whereas the sample set taken in the year 2013 was for the 500 and 1500 meter distance profiles from the foot of the dam. The year 2012 and 2013 sample sets for the 500m distance profile were sampled very similarly to each other. A kilogram of each sample was taken as per grid format. The samples at varied depths were taken at 0-cm depth for the top layer, 20cm depth for the second layer, and 30cm depth for the third layer. The samples for the surface varied distance were taken at 1 m, 2m, 3m, and 4m away from each 500m and 1500 sampling points. The 2012 samples were analysed using characterization methods namely ICP MS and The 2013 samples were analysed using the ICP OES. The comparison of the field results for the six heavy metals studied (A1, Fe, Pb, Cu, Ni and Cr) was performed using statistical analytical methods, namely ANOVA. The statistical analysis results for heavy metals (A1, Fe, Pb, Cu, Ni and Cr) from sample and 2013 revealed that the group means are not significantly different from each other which means that there is no significant difference in (A1, Fe, Pb, Cu, Ni and Cr) concentrations with respect to both depth and distance. The observations from both 2012 and 2013 indicate the results of the samples are in agreement. In addition, the comparative average concentrations of the three results obtained reach the same conclusion that the tailing dam probably does not introduce considerable or significant amounts of these metals (A1, Fe, Pb, Cu, Ni and Cr) into the surrounding soils. / Chemical Engineering / M. Tech. (Chemical Engineering)

Mining industry has been identified as the main sustenance of the South African economy, however the negative impacts of the industry on the ecological systems cannot be over emphasized due to the released waste which is mostly heavy metals into the environment. The study evaluated six heavy metal (A1, Cu, Fe, Ni, Pb and Cr) contents in a tailings dam from a specific mine site. Two sets of samples for the investigation were measured, that is, one in year 2012 and the other in year 2013. In the year 2012, the sample set was only taken at a distance profile of 500 meters from the foot of the dam, whereas the sample set taken in the year 2013 was for the 500 and 1500 meter distance profiles from the foot of the dam. The year 2012 and 2013 sample sets for the 500m distance profile were sampled very similarly to each other. A kilogram of each sample was taken as per grid format. The samples at varied depths were taken at 0-cm depth for the top layer, 20cm depth for the second layer, and 30cm depth for the third layer. The samples for the surface varied distance were taken at 1 m, 2m, 3m, and 4m away from each 500m and 1500 sampling points. The 2012 samples were analysed using characterization methods namely ICP MS and The 2013 samples were analysed using the ICP OES. The comparison of the field results for the six heavy metals studied (A1, Fe, Pb, Cu, Ni and Cr) was performed using statistical analytical methods, namely ANOVA. The statistical analysis results for heavy metals (A1, Fe, Pb, Cu, Ni and Cr) from sample and 2013 revealed that the group means are not significantly different from each other which means that there is no significant difference in (A1, Fe, Pb, Cu, Ni and Cr) concentrations with respect to both depth and distance. The observations from both 2012 and 2013 indicate the results of the samples are in agreement. In addition, the comparative average concentrations of the three results obtained reach the same conclusion that the tailing dam probably does not introduce considerable or significant amounts of these metals (A1, Fe, Pb, Cu, Ni and Cr) into the surrounding soils. / Chemical Engineering / M. Tech. (Chemical Engineering)

The application of an electric field to contaminated soil specimens and the resulting electrokinetic phenomena have been combined with the degradative actions of bacteria to create a novel method for the remediation of contaminated land. Currently, the vast majority of remediation projects involve disposing of contaminated soil in landfill. With the introduction of, and increases in, landfill tax in the UK, this option is becoming less desirable, and so robust, more sustainable techniques are required, such as bioremediation. A major problem with the implementation of bioremediation is the bioavailability of contaminating chemicals. Reduced accessibility of bacteria to the chemical(s) they are attempting to degrade can lead to significant increases in required remediation times, as well as the possibility of significant residual contamination, the levels of which cannot be easily further reduced. This thesis addresses the problem of bioavailability of contaminants in soils, and has investigated the use of electrokinetic phenomena as tools to bring about an increase in this factor, leading to improved biodegradation. Soil contaminated with pentachlorophenol (sodium salt) was subjected to an electric field in a number of experiments, with significant transport of the initially ionic chemical noted. The transport and fate of this chemical were tracked throughout each experiment, along with properties of the soil pore fluid. Significant changes in soil chemistry were noted (particularly pH or moisture content, depending on the experiment). The effect of pH change was found to be particularly important in this respect, with acidic conditions hindering both movement and bioavailability. A method of applying an electric field to contaminated soil containing degrading bacteria was developed which minimised the changes to these parameters within the soil. A significant increase in the effectiveness of the remediation was noted with this technique, with substantially faster degradation found to occur.