This dissertation focuses on aerosol transport modeling in occupational environments and mining sites in Arizona using computational fluid dynamics (CFD). The impacts of human exposure in both environments are explored with the emphasis on turbulence, wind speed, wind direction and particle sizes. Final emissions simulations involved the digitalization process of available elevation contour plots of one of the mining sites to account for realistic topographical features. The digital elevation map (DEM) of one of the sites was imported to COMSOL MULTIPHYSICS® for subsequent turbulence and particle simulations. Simulation results that include realistic topography show considerable deviations of wind direction. Inter-element correlation results using metal and metalloid size resolved concentration data using a Micro-Orifice Uniform Deposit Impactor (MOUDI) under given wind speeds and directions provided guidance on groups of metals that coexist throughout mining activities. Groups between Fe-Mg, Cr-Fe, Al-Sc, Sc-Fe, and Mg-Al are strongly correlated for unrestricted wind directions and speeds, suggesting that the source may be of soil origin (e.g. ore and tailings); also, groups of elements where Cu is present, in the coarse fraction range, may come from mechanical action mining activities and saltation phenomenon. Besides, MOUDI data under low wind speeds (<2 m/s) and at night showed a strong correlation for particles 1-micrometer in diameter between the groups: Sc-Be-Mg, Cr-Al, Cu-Mn, Cd-Pb-Be, Cd-Cr, Cu-Pb, Pb-Cd, As-Cd-Pb. The As-Cd-Pb group correlates strongly in almost all ranges of particle sizes. When restricted low wind speeds were imposed more groups of elements are evident and this may be justified with the fact that at lower speeds particles are more likely to settle. When linking these results with CFD simulations and Pb-isotope results it is concluded that the source of elements found in association with Pb in the fine fraction come from the ore that is subsequently processed in the smelter site, whereas the source of elements associated to Pb in the coarse fraction is of different origin. CFD simulation results will not only provide realistic and quantifiable information in terms of potential deleterious effects, but also that the application of CFD represents an important contribution to actual dispersion modeling studies; therefore, Computational Fluid Dynamics can be used as a source apportionment tool to identify areas that have an effect over specific sampling points and susceptible regions under certain meteorological conditions, and these conclusions can be supported with inter-element correlation matrices and lead isotope analysis, especially since there is limited access to the mining sites. Additional results concluded that grid adaption is a powerful tool that allows to refine specific regions that require lots of detail and therefore better resolve flow detail, provides higher number of locations with monotonic convergence than the manual grids, and requires the least computational effort. CFD simulations were approached using the k-epsilon model, with the aid of computer aided engineering software: ANSYS® and COMSOL MULTIPHYSICS®. The success of aerosol transport simulations depends on a good simulation of the turbulent flow. A lot of attention was placed on investigating and choosing the best models in terms of convergence, independence and computational effort. This dissertation also includes preliminary studies of transient discrete phase, eulerian and species transport modeling, importance of saltation of particles, information on CFD methods, and strategies for future directions that should be taken.

Surface mining of coal in the country leaves a lot of damage. This type of mining is characterized by the creation of large external dumps. The dumps often contain substrates with toxic substances or substances which become toxic after reaction with air. These substrates are toxic to plants and edaphon. This work is intended to show what properties of substrates are important for phytotoxicity. The location of research was selected including 3 different kinds of substrates, terrain unevenness and a lagoon in the middle. Coordinate grid has been created on the selected location. At each point a test was conducted with plant Sinapis alba and biomass was extracted from a naturally growing vegetation. Further, at the points substrates were collected and values of pH, conductivity and arsenic were measured. Test with plant Sinapis alba was repeated in the laboratory conditions as well. On site GPS coordinates were measured for the mathematical model created in ArcGIS. Experiment has shown the importance of the type of substrate and the geologic description, and then the association between dejection, value of pH and conductivity. Conductivity and pH levels also correlate with the germination Sinapis alba and biomass of naturally growing vegetation.

Field observation and manipulative experiments were carried out to describe and test important processes affecting the plant succession on Sokolov post-mining sites. Examined was mainly effect of dominant tree species (which are planted or spontaneously established) on understory plants, litter decomposability and effect of earthworms (Lumbricidae) on late successional plant species.

Les fortes teneurs en éléments traces métalliques (ETMs) présents dans les déblais miniers entraînent généralement une forte réduction de la diversité végétale et microbienne. Selon les caractéristiques physico-chimiques des sols, la nature des métaux, leur concentration et leur spéciation, seules certaines espèces végétales et microbiennes ont développé des mécanismes particuliers et se sont adaptées à la présence d'ETMs. C'est le cas d'Anthyllis vulneraria et d'Hedysarum coronarium, deux Fabacées qui sont présentes sur d'anciennes mines de Zn/ Pb respectivement au sud de la France et au nord de la Tunisie. L'étude de l'absorption du Zn chez quatre sous-espèces d'A. vulneraria a montré que seule la sous-espèce carpatica présente sur l'ancienne mine Zn/Pb des Avinières, peut croître en présence de teneurs élevées en Zn et accumule des quantités élevées de ce métal sans montrer de symptômes de toxicité. Les données obtenues ont révélé qu'A. vulneraria sous espèce carpatica est une plante hypertolérante et accumulatrice de Zn. L'inoculation d'A. vulneraria avec ses bactéries symbiotiques fixatrices d'azote, Mesorhizobium metallidurans STM2683 (souche métallicole) et Mesorhizobium sp. STM2682 (souche non métallicole), a induit une diminution très significative de la teneur en Zn dans la plante. Par contre, seule la souche métallicole a montré un effet protecteur vis-à-vis des sous espèces sensibles d'A. vulneraria lorsque celles-ci sont exposées à une concentration modérée en Zn. La diversité phylogénétique et phénotypique des bactéries symbiotiques fixatrices d'azote associées à H. coronarium isolées du substrat de l'ancienne mine de Zn/Pb de Fej El Hdoum et du sol d'une parcelle agricole à El Krib a mis en évidence (i) l'appartenance de tous les isolats étudiés au genre Rhizobium, (ii) l'existence de différents niveaux de tolérance au Cd et l'absence de tolérance au Zn pour les isolats issus du substrat de Fej El Hdoum (iii) le lien étroit entre la présence de la plante hôte, H. coronarium et de sa bactérie symbiotique fixatrice d'azote sur un site donné. Ainsi, compte tenu des contraintes imposées par la présence des ETMs, l'utilisation de Fabacées en première séquence de végétation pour favoriser l'entrée d'azote et faciliter l'installation d'une couverture végétale stable et pérenne à même de phytostabliser les déblais miniers, rend indispensable la sélection des associations les mieux adaptées aux conditions environnementales locales. / High contents of trace metals present in waste rock mining causes a significant reduction in plant and microbial diversity. According to soil physico-chemical characteristics, metal nature, concentration and speciation, only some plant and strain species have developed specific mechanisms to cope with trace metal toxicity. This is the case of Anthyllis vulneraria and Hedysarum coronarium, two Fabaceae that are present on Zn / Pb ancient mines respectively in southern France and northern Tunisia. The Zn absorption study in four subspecies of A. vulneraria showed that only the carpatica subspecies, present on the Zn / Pb ancient mine of Les Avinières, can grow with high Zn concentrations and accumulate high levels of this metal without showing toxicity symptoms. Thus, A. vulneraria subsp. carpatica should be considered as a Zn-hypertolerant and accumulator plant. Inoculation of A. vulneraria with a nitrogen-fixing symbiotic bacterium, Mesorhizobium metallidurans STM2683 (metallicolous strain) or Mesorhizobium sp. STM2682 (non- metallicolous strain), induced a significant decrease of Zn content in the plant. However, only the metallicolous strain showed a protective effect for sensitive A. vulneraria subspecies when symbiotic plants were exposed to a moderate Zn concentration. Phenotypic and phylogenetic diversity of nitrogen-fixing symbiotic bacteria associated with H. coronarium isolated from the Zn / Pb ancient mine of Fej El Hdoum and an agricultural parcel of El Krib highlighted (i) that all studied isolates belong to the genus of Rhizobium, (ii) the existence of different Cd tolerance levels and the absence of Zn tolerance for isolates from the Fej El Hdoum substrate (iii) the close link between the presence of the host plant, H. coronarium and their symbiotic nitrogen-fixing bacteria on a given site. Thus, given the constraints imposed by heavy metals, the use of Fabaceae in a first sequence of vegetation to promote nitrogen entrance and facilitate the installation of a sustainable plant cover able to phytostabilise waste rock mining, necessitates the selection of the best adapted associations to local environmental conditions.

Temporal Landscapes is a research project concerned with culture-nature relations in the context of contemporary industrial land use in New Zealand; explored visually through the photographic representation and presentation of gold mining sites – former, current and prospective – in the Hauraki region. In the current period of industrial capitalism, featuring the mass exploitation of natural resources, nature is commonly thought of as subservient to humankind. This stance, with its origin in scientific ideology of the 17th Century, is interesting to consider in relation to contemporary notions of landscape, and the ‘ideal’ in nature. In New Zealand, a balance is being sought between interests of sustainability and conservation, and of industry and economy. This is not to say that industry opposes environmental safeguards; in contrast, sustainable management including the rehabilitation of land post-industrialisation is integral to modern mining practice in New Zealand. With this emphasis on controlled industrial progress, two key factors emerge. Firstly, this level of control implicates itself as a utopian vision, and secondly, industrialisation is advocated as a temporary situation, with industrial land as transitory, on the path to rehabilitation. The research question of Temporal Landscapes asks; in considering contemporary industrial land use in New Zealand within a utopian framework – focussing specifically on gold mining in the Hauraki Region – has our ideal in nature become that of a controlled, even post-industrial, landscape? The photographic representation of these sites offers a means to explore and express their visual temporality. With the expectation of industrial sites as fleeting and rehabilitated sites as static utopias, it would seem that this industrial process is a kind of contemporary ideal. Presented as a flickering projection piece, 23 Views. (Prospective gold mining site, Golden Valley, Hauraki, 2008 / Martha gold mine and Favona gold mine, Waihi, Hauraki, 2008), and a set of selectively lit prints, Untitled I. (Garden, pit rim walkway, Martha gold mine, Waihi, Hauraki, 2008), Untitled II. (View of pit, former Golden Cross gold mine, Waitekauri Valley, Hauraki, 2008), and Untitled III. (View of water treatment pond, former Golden Cross gold mine, Waitekauri Valley, Hauraki, 2008), they act as landscapes of partial comprehension.

The paper follows up on previous analyses of changes in soil microstructure in the process of soil development on dumps around Sokolov, Czech Republic, using the soil thin section method. The distribution of structures in the topsoil of the profile was studied in two chronosequences, one overgrown with spontaneous vegetation and one reclaimed by alder planting. A comparison with historical data obtained at these locations 10 years ago was used, and, therefore, the same methods were also applied (Frouz et al., 2007b). The most distinct trend in the process of soil development over time, as observed through both a comparison of soil thin sections from various areas of chronosequence and changes in particular sites over time, is a gradual reduction of purely mineral structures and their replacement by organic matter - litter and its fragments, faecal pellets of arthropods, earthworms coprolites, and roots. This is illustrative of a high share of biogenic structures and a fundamental contribution of organisms to forming topsoil, a fact also pointed out by other authors. Keywords: Soil macrofauna; Soil microstructure; Soil thin section; Reclamation; Post-mining sites; Soil development; Earthworms

Depuis plus de 150 l’exploitation aurifère en Guyane française bouleverse le paysage en entrainant une déforestation massive des concessions minières. Les conséquences sont multiples, aussi bien pour l’environnement que pour la santé humaine. Pendant des décennies l’utilisation du mercure dans le processus d’extraction a entrainé une contamination du réseau hydrique et de la chaine trophique. Afin d’inscrire l’exploitation aurifère dans une optique de développement durable le code minier impose depuis 1998 une obligation de réhabilitation des sites exploités. Des méthodes de revégétalisation utilisant différentes essences végétales ont donc été adoptées afin d’accélérer les successions écologiques. Le contrôle de la qualité de restauration écologique est néanmoins difficile à mettre en œuvre et il est nécessaire d’avoir des outils de bio-géo-indications fiables et peu couteux pour estimer le recouvrement des fonctionnalités des écosystèmes et apprécier le risque de mobilités des éléments traces toxiques. Dans ce contexte, les objectifs de ce travail de thèse ont été d’évaluer la qualité de restauration écologique de sites miniers en Guyane française à travers une caractérisation des activités microbiennes, du fonctionnement des cycles biogéochimiques d’éléments majeurs (C,N,P) et de la dynamique du mercure. L’originalité de ce travail réside dans l’évaluation dans le temps et dans l’espace des interactions entre couvert végétal – propriétés physico-chimiques du sol – activités microbiennes – spéciation du mercure après revégétalisation et en faire un outils diagnostic de la réussite de cette restauration. Dans ce but, plusieurs campagnes d’échantillonnages ont été réalisées en Guyane sur un panel de sites miniers réhabilités, avec différents types de couverts végétaux. Des échantillons de sols ont été prélevés sur des sites revégétalisés avec des espèces de fabacées, et sur des sites non revégétalisés. Nous avons évalué les fonctionnalités des communautés microbiennes de ces sites avec plusieurs bio-marqueurs de la qualité du sol. Afin d’estimer le devenir du mercure, des mesures du mercure total ainsi que des spéciations opérationnelles et environnementales ont été réalisées. Ce travail de thèse a permis de mettre en évidence un effet positif de la revégétalisation sur la densité et les activités des communautés microbiennes telluriques. Les sites restaurés ont montré une biomasse microbienne, des taux de minéralisation des macroéléments (C,N,P), une diversité catabolique plus élevées que des sites non restaurés. Nos résultats confirment également que la restauration influence les activités des communautés microbiennes anaérobies. En effet, les travaux portant sur les communautés bactériennes ferri-réductrices (BFR) et sulfato-réductrices (BSR) montrent des activités variantes entre les modalités de revégétalisation. Ces différences sont à mettre en relation avec les propriétés physiques et chimiques du sol ainsi qu’avec la nature et la densité du couvert végétal. Les communautés BFR sont actives sur les sites réhabilités alors que les communautés BSR seraient davantage actives sur les sites faiblement restaurés. Ces différences ont des conséquences sur la mobilité du mercure. Nos travaux montrent également que si dans les sites revégétalisés le mercure est associé à des phases stables du sol alors que dans les sites non restaurés il est sous des formes solubles mobilisable dans le réseau hydrique, biodisponible pour les organismes de la chaine trophique. Pour conclure, l’approche interdisciplinaire proposée dans ce travail a permis d’identifier certains processus d’écologie microbienne fondamentaux impactant le recouvrement des fonctionnalités des écosystèmes miniers dégradés. Ce travail offre un outil d’évaluation de la qualité de la restauration écologique original, appliqué et prometteur, qui pourra intéresser les décisionnaires responsables de la réhabilitation des sites miniers en Guyane française / For more than 150 years, gold mining in French Guiana has disrupted the landscape by causing massive deforestation of mining concessions. The consequences are multiple, both for the environment and human health. Indeed, for decades the use of mercury in the extraction process has led to pollution of aquatic systems, contaminating the food chain. In order to ensure that gold mining is carried out in a sustainable development perspective, the Mining Code has imposed an obligation since 1998 to rehabilitate the sites operated. Several revegetation methods using different plant species have been adopted to accelerate ecological succession. However, quality control of ecological restoration is difficult to implement and it is necessary to have reliable and inexpensive bio-geo-indication tools to estimate the recovery of the functionalities of anthropized ecosystems and assess the risk of mobility of toxic metallic elements.In this context, the objectives of this thesis work were to evaluate the quality of ecological restoration of mining sites in French Guiana through a characterization of microbial activities, the functioning of biogeochemical cycles of major elements (C,N,P) and the dynamics of mercury. The originality of this work lies in the evaluation over time and space of the interactions between vegetation cover - physico-chemical properties of the soil - microbial activities - mercury speciation after revegetation and making it a diagnostic tool for the success of this restoration. To this end, several sampling campaigns were carried out in French Guiana on a panel of rehabilitated mining sites, with different types of vegetation cover. Soil samples were taken from replanted sites with fabaceous species (A. mangium and C. racemosa), and from non-restored sites. We then evaluated the main functionalities of the microbial communities of these sites through the use of several soil quality bio-markers. In order to estimate the fate of mercury, measurements of total mercury as well as operational and environmental specimens were carried out. This thesis work revealed a positive effect of revegetation on the density and activities of soil microbial communities. Sites restored with fabaceous species have thus shown microbial biomass, macro-element mineralization rates (C,N,P), and catabolic diversity significantly higher than sites that have not been restored. The associations of fabaceous plants show more conclusive results than the use of monoculture in terms of microbial functionalities. While the activities of aerobic microorganisms have been impacted by the return of vegetation, our results confirm that restoration influences the activities of anaerobic microbial communities. Indeed, work on iron-reducing (IRB) and sulfate-reducing (SRB) bacterial communities shows varying activities between revegetation modalities. These differences are related to the physical and chemical properties of the soil and the nature and density of the vegetation cover. BFR communities are more active on rehabilitated sites while SRB communities are more active on poorly restored sites. These differences in activities have consequences on mercury mobility and methylation. Our work also shows that while mercury in re-vegetated sites is associated with stable phases of the soil, including iron oxides, in non-restored sites it is in soluble forms that can potentially be mobilized in the water network, bioavailable and assimilated by organisms in the food chain.In conclusion, the interdisciplinary approach proposed in this work made it possible to identify certain fundamental microbial ecological processes that impact the recovery of the functionalities of degraded mining ecosystems. This work provides an original, applied and promising tool for assessing the quality of ecological restoration that may be of interest to decision-makers responsible for the rehabilitation of mining sites in French Guiana