Les glaciers intègrent naturellement des informations hydrologiques et énergétiques dans des régions climatiques variées du globe et sont sensibles à des changements minimes de bilan d’énergie de surface. Parmi les paramètres mesurés in-situ traduisant les variations climatiques, le bilan de masse de surface est la variable directement reliée aux conditions atmosphériques qui contrôlent les processus d’accumulation et d’ablation. Un grand nombre de modèles, de complexités diverses, existent pour simuler l’évolution du bilan de masse. Cependant, des questions perdurent quant à l’utilisation de l’approche la plus appropriée, notamment sur de longues périodes de temps. Basés sur de longues séries de mesures réalisées sur quatre glaciers des Alpes françaises (issues du service d’observation GLACIOCLIM), ces travaux de thèse ont pour but d’étudier la sensibilité du bilan de masse aux variables atmosphériques et topographiques, afin d’identifier celles essentielles pour contraindre les modèles.En s’appuyant tout d’abord sur une approche empirique, nos résultats indiquent que pour chaque glacier, la variabilité temporelle de l’ablation s’explique principalement par la variabilité de la température tandis que la variabilité spatiale de la fonte de la neige et de la glace est largement gouvernée par l’insolation. Néanmoins, à l’échelle du glacier, considérer l’insolation en plus de la température ne conduit pas à une amélioration de la performance des modèles empiriques et un modèle type degré-jour apparaît suffisant pour simuler son bilan de masse. L’utilisation du modèle à base physique SURFEX/ISBA-Crocus a permis d’étudier la sensibilité du bilan de masse estival à chacune des variables du bilan d’énergie de surface. Le modèle s’avère très performant pour la simulation des bilans spatialisés, mais nécessite un forçage météorologique précis et distribué spatialement. En particulier, le vent, souvent complexe à représenter dans les modèles atmosphériques,apparaît comme un facteur prépondérant pour modéliser correctement les processus de fonte. Avec des forçages météorologiques bien contraints, ces deux approches (empirique et physique) se révèlent très performantes quant à la modélisation du bilan de masse estival. Toutefois, nos résultats montrent que les bilans annuels restent très conditionnés par les bilans hivernaux du fait de la rétroaction de l’albédo de surface. Une attention particulière a donc été portée sur la simulation de l’accumulation.A partir des données de l’observatoire GLACIOCLIM, notre étude n’a pas permis d’établir de relation significative entre la variabilité spatio-temporelle des bilans hivernaux et les variables morpho-topographiques.Pour cette raison, une campagne spécifique basée sur des mesures LiDAR a été mise en œuvre au Col du Midi (Massif du Mont-Blanc) afin d’affiner le réseau de mesures et d’améliorer la compréhension de la variabilité spatio-temporelle de la couverture neigeuse. Nos résultats montrent la complexité d’obtenir des mesures d’accumulation par différence de MNT, du fait des vitesses d’émergence/submergence. / Glaciers naturally record hydrological and energetic information into varied climatic regions of the world, and are sensitive to small changes in their surface energy balance. The glacier surface mass balance is directly linked to the atmospheric variables which control accumulation and ablation processes. Many models, with different complexities, enable simulations of mass balance evolution, but some questions arise about the best approach to use, especially over long time periods. Based on long measurement series on four glaciers in the French Alps (GLACIOCLIM observatory), this thesis aims at studying the mass balance sensitivity to climatic variations, to identify relevant meteorological variables for modelling. Based on an empirical approach performed on each glacier, temperature was found to be the main driver of temporal ice/snow ablation variability while solar radiations strongly influence the spatial distribution of summer mass balance. However, at glacier scale, to include solar radiation in melt models does not improvethe performances and a classical degree-day model is sufficient to simulate glacier-wide mass balance.The snowpack model SURFEX-ISBA-Crocus was then used to study summer mass balance sensitivity to all surface energy balance fluxes. Results indicate good performances of the model to simulate mass balance at each stake, but it requires accurate meteorological forcing. In particular wind, generally difficult to assessby atmospheric models, appears as a key factor for an accurate ablation modelling. Our work emphasizes that both physical and empirical approaches are very efficient for ablation modeling when forced with accurate meteorological data. Yet, annual mass balances remain very sensitive to wintermass balance due to the surface albedo feedback. For this reason, simulating accumulation processes remainsas important as ablation modelling. Using GLACIOCLIM data measurements, our study failed to find relevant relationship between winter mass balance and topographical variables such as slope, aspect, elevation, due to insufficient spatio-temporal resolution. To fill this gap of measurements, we set up a dedicated field campaign to improve our understanding of the spatio-temporal variability of the snow depth distribution on Alpineglaciers. This year-round campaign was performed using LiDAR acquisitions at Col du Midi (Mont Blancmassif). Results underline the complexity of accurate accumulation measurements from DEM differences due to submergence/emergence velocities.

La qualité globale des eaux continentales (lacs et réservoirs) continue à se détériorer dans de nombreuses régions du Mexique. Le réservoir Cointzio, situé dans la partie sud du Plateau Central Mexicain, sur la ceinture “Trans-Mexicain Volcanique Belt » (TMVB), ne fait pas exception. Ce réservoir tropical turbide est un système monomictique chaud (surface = 6 km2, capacité = 66 Mm3, temps de séjour ~ 1 an). Il est stratégique pour l'approvisionnement en eau potable de la ville de Morelia, capitale de l'état du Michoacán, et pour l'irrigation en aval pendant la saison sèche. Le réservoir est menacé par l'accumulation des sédiments et des nutriments provenant d'eaux non traitées dans le bassin versant amont. La haute teneur en particules d'argile très fines et le manque d'installations de traitement de l'eau conduisent à de graves épisodes d'eutrophisation (jusqu'à 70 µg chl. a L-1) ainsi qu'à des périodes saisonnières de forte turbidité (profondeur de Secchi < 30 cm) et d'anoxie (de Mai à Octobre). Sur la base de mesures intensives de terrain réalisées en 2009 (échantillonnage dans le bassin versant, sédiments déposés, profils verticaux de l'eau, bilan entrées et sorties) nous avons présenté une étude intégrée du fonctionnement hydrodynamique et biogéochimique du réservoir Cointzio. Les profils verticaux de température (T), de concentration en sédiment en suspension (TSS), d'oxygène dissous (DO), de chlorophylle a, de carbone et de nutriments ont été utilisés pour évaluer les cycles internes au réservoir. Pour compléter l'analyse des données de terrain, nous avons examiné la capacité de différents modèles numériques 1DV (Aquasim modèle biogéochimique couplé avec le modèle de mélange k-ε) à (i) reproduire les principaux cycles biogéochimiques dans le réservoir Cointzio et (ii) préciser les scénarios de réduction des éléments nutritifs (P and N) pour limiter l'eutrophisation dans les prochaines décennies. Le modèle k-ε s'est avéré le plus robuste pour reproduire les conditions hydrodynamiques, en particulier la stratification modérée liée à la très grande turbidité et au régime soutenu de vent thermique. Le modèle Aquasim s'est avéré pertinent pour reproduire les principaux cycles de l'oxygène dissous DO, des nutriments et de la chlorophylle a au cours de l'année 2009. Les différentes simulations ont souligné l'impact négatif à long terme du réchauffement climatique. A la fin du siècle (2090), une augmentation de la température de l'air atteignant 4.4° C a été prédite à partir de modèles de circulation mondiale. Couplé avec une année hydrologique sèche, une telle situation pourrait conduire à des conditions anoxiques sévères et à des blooms importants de chlorophylle a (jusqu'à de 94 µg L-1). Diverses simulations ont montré que la réduction drastique de l'apport de nutriments (à 90%) serait nécessaire pour réduire de façon significative les teneurs en chlorophylle a. Si de telles mesures d'atténuation sont adoptées, le pic maximal de chlorophylle a se stabiliserait à 40 µg L-1, au lieu de 94 mg L-1, après une période de cinq ans d'efforts. À notre connaissance, cette étude fournit la première application numérique de modèles k-ε et AQUASIM pour simuler les niveaux d'eutrophisation élevés dans un réservoir tropical très turbide. / La qualité globale des eaux continentales (lacs et réservoirs) continue à se détériorer dans de nombreuses régions du Mexique. Le réservoir Cointzio, situé dans la partie sud du Plateau Central Mexicain, sur la ceinture “Trans-Mexicain Volcanique Belt » (TMVB), ne fait pas exception. Ce réservoir tropical turbide est un système monomictique chaud (surface = 6 km2, capacité = 66 Mm3, temps de séjour ~ 1 an). Il est stratégique pour l'approvisionnement en eau potable de la ville de Morelia, capitale de l'état du Michoacán, et pour l'irrigation en aval pendant la saison sèche. Le réservoir est menacé par l'accumulation des sédiments et des nutriments provenant d'eaux non traitées dans le bassin versant amont. La haute teneur en particules d'argile très fines et le manque d'installations de traitement de l'eau conduisent à de graves épisodes d'eutrophisation (jusqu'à 70 µg chl. a L-1) ainsi qu'à des périodes saisonnières de forte turbidité (profondeur de Secchi < 30 cm) et d'anoxie (de Mai à Octobre). Sur la base de mesures intensives de terrain réalisées en 2009 (échantillonnage dans le bassin versant, sédiments déposés, profils verticaux de l'eau, bilan entrées et sorties) nous avons présenté une étude intégrée du fonctionnement hydrodynamique et biogéochimique du réservoir Cointzio. Les profils verticaux de température (T), de concentration en sédiment en suspension (TSS), d'oxygène dissous (DO), de chlorophylle a, de carbone et de nutriments ont été utilisés pour évaluer les cycles internes au réservoir. Pour compléter l'analyse des données de terrain, nous avons examiné la capacité de différents modèles numériques 1DV (Aquasim modèle biogéochimique couplé avec le modèle de mélange k-ε) à (i) reproduire les principaux cycles biogéochimiques dans le réservoir Cointzio et (ii) préciser les scénarios de réduction des éléments nutritifs (P and N) pour limiter l'eutrophisation dans les prochaines décennies. Le modèle k-ε s'est avéré le plus robuste pour reproduire les conditions hydrodynamiques, en particulier la stratification modérée liée à la très grande turbidité et au régime soutenu de vent thermique. Le modèle Aquasim s'est avéré pertinent pour reproduire les principaux cycles de l'oxygène dissous DO, des nutriments et de la chlorophylle a au cours de l'année 2009. Les différentes simulations ont souligné l'impact négatif à long terme du réchauffement climatique. A la fin du siècle (2090), une augmentation de la température de l'air atteignant 4.4° C a été prédite à partir de modèles de circulation mondiale. Couplé avec une année hydrologique sèche, une telle situation pourrait conduire à des conditions anoxiques sévères et à des blooms importants de chlorophylle a (jusqu'à de 94 µg L-1). Diverses simulations ont montré que la réduction drastique de l'apport de nutriments (à 90%) serait nécessaire pour réduire de façon significative les teneurs en chlorophylle a. Si de telles mesures d'atténuation sont adoptées, le pic maximal de chlorophylle a se stabiliserait à 40 µg L-1, au lieu de 94 mg L-1, après une période de cinq ans d'efforts. À notre connaissance, cette étude fournit la première application numérique de modèles k-ε et AQUASIM pour simuler les niveaux d'eutrophisation élevés dans un réservoir tropical très turbide.

The inadvertent ingestion of contaminated soil is the dominant exposure route of non-volatile and semi-volatile contaminants such as polycyclic aromatic hydrocarbons (PAHs). Quantitative mass balance soil ingestion studies have been used to determine soil ingestion rates for use in human health risk assessments (HHRA) that can be used to predict the likelihood of adverse effects in individuals exposed to hazardous contaminants such as PAHs in contaminated soil. The Cold Lake region of Alberta is one of the three major oil sands regions of Alberta, and PAH concentrations in this oil sand region may be elevated in the atmosphere and the soil, resulting in increased exposures to PAHs. The area is home to Cold Lake First Nation who practice traditional activities and lifestyles that may put them in greater contact with soil than previous soil ingestion studies suggest. The primary objective of this research was to assess the soil ingestion rate in a group of First Nations subjects inhabiting the Cold lake region, and assess the carcinogenic risk posed by exposures to PAHs in air and soil. The study employed a quantitative mass balance tracer approach to estimate soil ingestion rates, and followed 9 subjects over a 13 day period. Soil and air samples were simultaneously collected to assess PAH contamination. The mean soil ingestion rate using Al and Si elemental tracers was 52 mg d-1, with a 90th percentile of 220 mg d-1, and a median soil ingestion rate of 37 mg d-1. These values are greater than the soil ingestion rates for HHRA recommended by Health Canada. The mean increase in excess lifetime cancer risk posed by inadvertent ingestion of soil to a First Nations’ individuals following traditional activities was 0.02 cases per 100,000 people with a 95% risk level of 0.067 cases per 100,000 people. Exposure to PAHs through inhalation posed a maximum lifetime cancer risk below 0.1 cases per 100,000, people. Thus, this study found no appreciable increase in excess lifetime associated with PAH exposure of First Nations’ people in the Cold Lake region.

Orientador : Yong Kun Park / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T01:01:25Z (GMT). No. of bitstreams: 1 Lui_MariaCristinaYoun_M.pdf: 779941 bytes, checksum: aa1237e20c91ff048441111b62275d6b (MD5) Previous issue date: 2004 / Mestrado / Mestre em Ciência de Alimentos

The commercial production of broiler chickens emits low amounts of nitrous oxide and methane, however, the production of CO2 and NH3 is considerable. Several countries have sought to investigate the emissions of greenhouse gases (GHG) and ammonia (NH3) in the production of broiler chickens since the information available in the literature is variable and uncertain. This is due to the diversity and particular conditions of the facilities, as well as the innumerable differences in the production system and the complex interactions observed in animal waste. Currently, gaseous pollutant measurements are costly techniques and difficult to put into practice in a large number of operations. The impacts of agriculture on global warming must be measured to allow Brazil to meet the commitments signed in COP-21 and to manage its production more precisely. In order to obtain reliable results, it is necessary to know the emission factors for the diverse production systems in the country. In view of this complexity, this research sought to apply a simplified sampling and emission determination technique that present low cost, simplicity, and robustness. The methodology uses the principle of concentration relations as a reference and determination of the concentration of gases was performed by INNOVA 1412. Weekly monitoring of concentrations of NH3, CO2, CH4, and N2O was conducted, considering the typical management of reused litter. The air quality was evaluated for the concentrations of NH3 and CO2, as recommended by international institutions. In addition, the thermal comfort of broiler house, considering the enthalpy index proposed in the literature and zootechnical performance, were measured. In order to identify the variables that best describe the emission flux of NH3 and CO2, mixed linear models with up to six variables were tested. N, C, and P balances were conducted for each production cycle in order to account for the inputs and outputs of the elements, as well as to verify the accuracy of the methodologies used. The main input of N, C, and P in the system was from reused litter, followed by the feed. The emissions allowed for the calculation of annual losses of 16 ± 4; 61 ± 16, and 168 ± 43 g of N2O, CH4, and NH3 bird-place-1 yr-1, respectively. Considering that this research presents an applicable and innovative methodology to determine GHG flows in broiler house for the country, the data will be useful for the Brazilian annual production of GHG emissions from poultry. The results are also useful to encourage new research that promotes knowledge of GHG emissions and alternatives to decrease emissions for meat production in Brazil. / A produção comercial de frangos de corte emite baixas quantidades de óxido nitroso e metano, no entanto, a produção de dióxido de carbono e amônia é considerável. Vários países têm buscado investigar as emissões de gases do efeito estufa (GEE) e amônia (NH3) na produção de frangos de corte já que as informações disponíveis na literatura são variáveis e incertas devido à diversidade das instalações, bem como das inúmeras diferenças no sistema de criação e das complexas interações observadas nos dejetos dos animais. Atualmente, a determinação das emissões gasosas exigem técnicas com custo elevado e difíceis de colocar em prática em um número elevado de instalações. Além disso, os impactos dos sistemas produtivos sobre o aquecimento climático devem ser medidos para permitir que o Brasil atenda os compromissos firmados na COP-21 e execute seu inventário de maneira mais precisa. A fim de obter resultados confiáveis é necessário conhecer os fatores de emissão na diversidade de sistemas de produção existentes no país. Diante dessa complexidade, nesta pesquisa buscou-se aplicar uma técnica simplificada de amostragem e determinação das emissões que apresenta baixo custo, simplicidade e robustez. A metodologia utiliza como referência, o princípio das relações de concentração e a concentração dos gases, que nesse casso foi determinada pelo INNOVA 1412. Buscou-se monitorar semanalmente as concentrações de NH3, CO2, CH4 e N2O considerando o manejo de reutilização da cama de frango. A qualidade do ar foi avaliada, considerando as concentrações de NH3 e CO2 recomendadas por instituições internacionais, assim como o conforto térmico dos aviários considerando os índices de entalpia propostos na literatura e o desempenho zootécnico. Determinou-se os fatores de emissão. E para identificar as variáveis que melhor descrevem o fluxo de emissão de NH3 e CO2, foram testados modelos lineares mistos com até seis variáveis. Balanços de N, C P foram conduzidos para cada ciclo de produção com a finalidade de contabilizar as entradas e saídas dos elementos e verificar a precisão das metodologias utilizadas. A principal entrada de N e C no sistema foi pela reutilização da cama, seguida pela ração. As emissões permitiram calcular perdas anuais de 16 ± 4; 61 ± 16; e 168 ± 43 g de N2O, CH4 e NH3 ave-alojada-1 ano-1, respectivamente. Considerando que esta pesquisa apresenta uma metodologia aplicável e de baixo custo para determinar as emissões de GEE em aviários de frangos de corte no Brasil, os resultados são úteis para incentivar novas pesquisas que possam avançar no conhecimento das emissões e possíveis técnicas de mitigação de GEE na produção de frangos de corte no Brasil.

Lead (Pb), occurs both naturally and as a pollutant in Arctic landscape systems. The ongoing climate change, especially pronounced in the Arctic, changes the premises for Pb transport and mobility. Thus, to predict future development of both natural and pollution Pb, an increased understanding of their storages and flows in an Arctic system is of interest. Here, a Pb mass-balance budget for an entire catchment in West Greenland was calculated. The budget shows that most Pb is stored in terrestrial soils (94%), while 6% of total catchment Pb is in lake sediments. Other Pb-pools are small in comparison (&lt;1% combined). The entire catchment system has a negative balance, with annual inputs of 44 g Pb from precipitation and 67 g Pb from eolian deposition, while 150 g Pb is removed from the system (through sedimentation). Limited lake water outflow (o.15 g Pb yr-1) suggests that the catchment in its entirety acts as a Pb-sink. The terrestrial system, however (wet deposition input of 34 g Pb and hydrological export of 68 g Pb annually), is considered to be a Pb-source to the aquatic system. The magnitude of hydrological and eolian transport is similar, however the former is more important for pollution Pb transport where the latter is more important for natural Pb. The fate of pollutant Pb is determined by future climate change. Wetter conditions could lead to a prolonged export of Pb further down-stream. If drier conditions prevail, eolian transport will be more important and pollution Pb could stay in soils.

The efficiency to improve the water quality of industrial and municipal wastewater in a constructed wetland/filter basin treatment system was investigated. The wetland system was constructed in a closed phosphate mine used for clay settling and sand tailings in Polk County, Florida. During 18-months of monitoring the chemical/microbiological composition of treated wetland water remained relatively constant, despite significant seasonal variations in temperature, rainfall and humidity. The following changes in water quality between input and output were observed: substantial decrease of water temperature (up to 10°C), reduction of As, SO4, F, Cl, NO3, NO2, Br, Na, K, Ca, and Mg, change in pH from 9 to 6.5-7, increase of H2S (up to 1060 micrograms/L), and a change from positive to negative ORP. There were no exceedances of the primary drinking water standards, volatile organic compounds, synthetic organic compounds, and radionuclides, but a number of exceedances for the secondary drinking water standards (Al, F, Fe, Mn, color, odor, total dissolved solids, and foaming agents). The concentration of fecal and total coliform bacteria in the wetland water was high, but subsequently reduced during filtration in the filter basin from 30 - 730 and 1000 - 7000 count/100 mL to < 2 and < 100 count/ 100 mL, respectively. To resolve the complex hydrogeological conditions a combined isotope/chemical mass-balance approach was applied. The results were the following: (1) the composition of water in the wetland varied throughout the period of the study; (2) a change in isotopic composition along the wetland flow path; (3) the wetland contained mainly wastewater (88 - 100 %) during normal pumping operations; however, hurricanes and inconsistent pumping added low conductivity water directly and triggered enhanced groundwater inflow into the wetland of up to 78 %; (4) the composition of water in monitor wells was mostly groundwater dominated; however periodically seepage from a water body to the north was detected; and (5) seepage from adjacent water bodies into the wetland was not identified during operation, which would indicate a potential water loss from the wetland. To test if the wetland system could be a prospective pre-treatment option for water used in aquifer storage and recovery (ASR) scenarios, a set of bench-scale leaching experiments was carried out using rocks from the Avon Park Formation, the Suwannee Limestone and the Ocala Limestone. Since As in the Floridan Aquifer was mainly present as an impurity in the mineral pyrite the elevated iron and sulfide concentrations in the wetland water were thought to prevent pyrite dissolution. The experiments which covered a range of redox conditions showed that the amount of As released from the aquifer matrix was not perfectly correlated with the bulk rock As concentration, nor the redox state of the water. The following important results were obtained: (1) the highest concentration of As was leached from the Avon Park Formation and the lowest - from the Suwannee Limestone, although the Ocala Limestone had the lowest bulk rock As; (2) minor to no As was released using native Floridan groundwater; (3) Tampa tap water, which chemically and physically resembled the ASR injection water, caused the As leaching of up to 27 micrograms/L, which was higher than the As drinking water standard; (4) the wetland and filter basin waters caused the highest release of As (up to 68 micrograms/L), which was unexpected because those water types were less oxygenated than Tampa tap water and thus should be less aggressive; (5) the in-situ filtration of the wetland water through a 0.2 micrometer membrane resulted in a reduction of As from 30 microgram/L to 16 microgram/L; and (5) the UV treatment significantly reduced both fecal and total coliform bacteria, but facilitated the increase of DO in initial waters, a change from negative to positive ORP, and the increase of As concentration in leachates. The experiments confirmed that perturbations of native aquifer conditions caused the release of As from the Floridan aquifer matrix, although the reaction may not be as simple as the dissolution of pyrite by oxygen, but additionally governed by a complex set of factors including the ORP of the system, SO4²?/S², Fe³?/Fe²?, dissolved organic carbon and microbial activity. In addition, the trend of As leaching could be governed by a set of factors, such as the porosity and permeability of the aquifer matrix influencing the rate and degree of free water saturation, amount of pyrite to be exposed to the preferential water flow paths, limited surface reactivity of pyrite with favored reactions on fractured mineral surfaces, the concentration and the selective leaching of As from individual pyrite crystals. To characterize and verify the geochemical processes in the column experiments, the Geochemist's Workbench reactive transport models (React and X1t) were developed. Results from the models correlated well to those from the column experiments and confirmed the following: (1) the water-rock reaction between the aquifer matrix and native groundwater was favorable for pyrite stability preventing the release of As into solution; (2) the injection of oxidizing surface water into reducing native groundwater caused a change in redox potential of the system thus promoting the dissolution of pyrite, and (3) 1D reactive transport model of water-rock reaction between the aquifer matrix and surface water indicated a diverse behavior of As along the column, such as the oxidative dissolution of pyrite, mobilization and simultaneous sorption of As onto neo-formed HFO, followed by the reductive dissolution of HFO and secondary release of adsorbed As, and the potential non-oxidative dissolution of pyrite contributing the additional source of As to the solution.

As the climate is changing, there are clear impacts on the mass balance of glaciers. A glacier can be defined as the result of sufficient accumulation, in the form of snow and rain, compared to its ablation, the different types of glacial loss, a balance that then determines the size of the glacier. A phenomenon in glacial environments where processes and effects on the environment are still relatively unknown arethe so-called firn aquifers. Firn aquifers are a type of “glacial groundwater” where water seeps through the firn, a form of more compact snow, and then accumulates and forms masses of water on top of the more compact ice. These water reservoirs can then affect glacial hydrology, mass balance, and the ice dynamics in the area by acting as a buffer for the meltwater on the way to the sea, causing and intensifying hydrofracturing, lowering the glacier’s albedo as well as acting as a heat source which in turn can deform the underlying ice. In 2018 and 2019, Ground Penetrating Radar measurements were made on Lomonosovfonna, a glacier on Svalbard, to measure the position and water level of one of the glaciers’ firn aquifers. The purpose of this study is to compare the radar data with measured data of the snow and firn density (stake measured during 2012, 2014, and 2016 at three different locations) to see what effects the density profile has on the radar-derived depth measurements. For this, ArcGIS was used to plot the intersection points of 2018 and 2019, to compare the two year’s different depth to the underlying water table. Then, MATLAB was used with the stake measured density profile and interpolated with the calculated depth values with the same two-way travel time as the GPR data to correlate the depths to the same intersection points. The general result showed that the firn densityprofile did have an impact on the data, but not significantly enough to alter the overall values as the change between the two years are of the similar magnitude. There are many different variables that could have played a role in the achieved results and further research needs to be done in order to establish a more in-depth conclusion / När klimatet förändras finns det tydliga effekter på glaciärernas massbalans. En glaciär kan definieras som resultatet av tillräcklig ackumulering, i form av snö och regn, jämfört med dess ablation, de olika typerna av glaciärförlust, en balans som sedan avgör glaciärens storlek. Ett fenomen i glaciala miljöer där processer och effekter på miljön fortfarande är relativt okända är de så kallade firn akvifärerna. Firn akvifärer är en typ av "glacialt grundvatten" där vatten sipprar genom firnen, en form av mer kompakt snö, och sedan ackumuleras och bildar vattenmassor ovanpå den underliggande isen. Dessa lagringar av vatten kan sedan påverka glacialhydrologin, massbalansen och isdynamiken i området genom att bland annat fungera som en buffert för smältvattnet på väg mot havet, orsaka och intensifiera hydrofrakturering, sänka glaciärens albedo samt fungerar som en värmekälla som i sin tur kan deformera den underliggande isen. År 2018 och 2019 gjordes Georadar-mätningar på Lomonosovfonna, en glaciär på Svalbard, för att mäta positionen och vattennivån för en av glaciärernas akvifärer. Syftet med denna studie är att jämföra radardata med uppmätt data från snö- och firndensitet (uppmätt under 2012, 2014 och 2016 på tre olika platser) för att se vilka effekter densitetsprofilen har på radarhärledda djupmätningar. För detta användes ArcGIS för att plotta skärningspunkterna för 2018 och 2019 och att sedan jämföra de två årens olika djup med den underliggande vattenytan. Sedan användes MATLAB med den uppmätta densitetsprofilen, och interpolerades med de beräknade djupvärdena med samma tvåvägs-restid som GPR-data uppmätt för att korrelera djupen till samma skärningspunkter. Det allmänna resultatet visade att firn densiteten hade en inverkan på data, men inte tillräckligt signifikant för att ändra de övergripande värdena eftersom förändringen mellan de två åren är av samma storlek. Det finns många olika variabler som kunde ha spelat en roll i de uppnådda resultaten och ytterligare forskning behöver göras för att fastställa en mer djupgående slutsats.

The major challenges currently facing the mining industry are related to the growing trend to deal with deeper ore bodies and consequently increasing complex ores. This has led to the development of new approaches to tackle incoming issues by integrating different parts of the value chain in order to offer appropriate solutions. One of these is the geometallurgical approach, which seeks to integrate geology and mineral processing to optimize ore beneficiation. This assessment can be carried out using a methodology called "Particle Tracking" that basically allows to go a step forward in the study of the phenomena occurring during ore beneficiation from the common assessment by size to the particle level. In other words, this methodology enables to incorporate to the analysis mineral liberation and the different mineral phases in particles. This is essentially what is described in literature as “Particle based approach”. This way, streams are regarded as a set of particles that have different properties and therefore their deportment throughout beneficiation vary accordingly. The purpose of this work was to apply “particle tracking” to samples from Pyhäsalmi beneficiation plant in central Finland. Rougher and scavenger flotation cells of the copper circuit were the main focus of this study. Mineral liberation analysis was used over samples of feed, concentrate and tailings for both rougher and scavenger. Mass balance and reconciliation were performed for bulk streams, streams divided by size and particle classes (classification of particles based on liberation degree) using HSC10 software from Outotec. The main findings show that recovery of chalcopyrite in rougher is above 80% over all size fractions, highest recovery is achieved at 90 µm and most liberated chalcopyrite particles present in the ore were reported to rougher concentrate. In case of scavenger, recovery to concentrate is reduced to a highest value of 66% between 60 µm to 80 µm with pronounced variation over size fractions. Most of chalcopyrite bearing minerals reported to scavenger concentrate are binary (two mineral phases) and complex (more than two mineral phases). Final tailings exhibit minimum amount of chalcopyrite, which is a good indicator of the efficiency of the copper circuit. In terms of recovery of chalcopyrite bearing particles, rougher reported to the first concentrate mainly liberated, binary and complex particles. An interesting finding was that complex particles to the first concentrate showed a particular high recovery. The second rougher concentrate mostly reported liberated and binary particles. As for scavenger, the first concentrate mostly reported liberated and complex particles while the second concentrate mainly reported complex particles. Final tailings exhibit essentially complex particles linked to coarse size fraction and the bulk grade of chalcopyrite for that stream was found to be noticeably low. / <p>The presentation was made through the zoom platform</p>

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