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Diesel particulate matter (DPM) is the solid portion of diesel exhaust. DPM occurs primarily in the submicron range, and poses a number of respiratory and other health hazards including cardiovascular and pulmonary disease. Underground miners typically have the highest DPM exposures compared to other occupations. This is because many mines are characterized by confined work spaces and large diesel equipment fleets. Exposures can be a particularly high hazard in large opening mines where ventilation can be challenging. As such, DPM monitoring is critical to protecting miner health and informing a range of engineering decisions. DPM is primarily composed of two components, elemental carbon (EC) and organic carbon (OC), which are often summed to report total carbon (TC). The ratio of EC to OC, and presence of a number of other minor constituents such as sorbed metals, can vary with many factors such as engine operating conditions, maintenance, fuel types and additives, and the level and type of exhaust after-treatments used. Given its complexity, DPM cannot be measured directly, and either TC or EC are generally used as a surrogate. Currently, the Mining Safety and Health Administration (MSHA) limits personal exposures of underground metal/non-metal miners to 160 µg TC/m3 on an 8-hr time weighted average basis. Compliance is demonstrated by collecting full-shift personal filter samples, which are later analyzed using the NIOSH 5040 Standard Method. For engineering purposes, area samples can also be collected and analyzed. The typical lag time between sample collection and reporting of results is on the order of weeks, and this presents a real problem for identifying and remediating conditions that led to overexposures or high DPM in area samples. The handheld FLIR Airtec monitor was developed to provide real-time DPM data and allow immediate decision making. The monitor works on a laser extinction principle to measure EC, the black component of DPM, as mass accumulates on a filter. The Airtec has proven useful for personal monitoring and short-term DPM surveying. However, capabilities are needed for continuous, long-term monitoring. Continuous DPM monitoring would be highly valuable for applications such as design and operation of ventilation on demand systems, or engineering studies of new ventilation, exhaust treatment or other DPM controls. The work presented in this thesis considers three continuous monitors, two of which are already commercially available: Magee Scientific's AE33 black carbon (BC) Aethalometer and Sunset Laboratory's Semi-Continuous OCEC Field Analyzer. The third monitor, called the Airwatch, is still in development. The AE33 and Airwatch effectively operate on the same principle as the Airtec, but include a self-advancing filter tape to allow autonomous operation over relatively long periods of time. The OCEC field monitor is essentially a field version of the laboratory analyzer used for traditional 5040 Method analysis. The AE33 has been briefly demonstrated in mine environments in a couple of other studies, but further testing is needed. The current prototype of the Airwatch and the OCEC field monitor have never been mine-tested. Two separate studies are reported here. The first is a field study in an underground stone mine that tested the Airwatch prototype and AE33 head-to-head under relatively high DPM conditions. Results demonstrated that both instruments could track general trends, but that further work was needed to identify and resolve issues associated with use of both instruments in high-DPM environments – and with basic design elements of the Airwatch. Additionally, the need to calibrate the monitors' output data to the standard measure of EC (i.e., 5040 Method EC) was made clear. In the second study, laboratory testing was conducted under very controlled conditions to meet this need, and another round of field testing was also done. The second study also included the OCEC field monitor. The laboratory tests yielded data to allow interpretation of the AE33 and Airwatch results with respect to 5040 EC. These tests also shed light on the current range EC concentrations over which these monitors can provide reliable data – which is indeed a primary range of interest for mines. As expected, the OCEC field monitor was shown to produce lab-grade results across a wide range of concentrations. The field testing in the second study demonstrated that all three monitors could operate autonomously in a mine environment over extended periods of time (i.e., weeks to months). Overall, it can be concluded that the AE33 and OCEC field monitor represent off-the-shelf options for DPM monitoring in mines, and the Airwatch might be another option if fully developed in the future. Selection of a particular monitoring tool should include careful consideration of specific factors including data quality needs, conditions in the intended monitoring location(s), and general user friendliness of the monitor. / Master of Science

At international border areas that suffer from poor quality, assessment of pollutant sources and transport across the border is important for designing effective air quality management strategies. As part of the Cal-Mex 2010 field campaign at the US-Mexico border in San Diego and Tijuana, we measured black carbon (BC) concentrations at three locations in Mexico and one in the United States. The measurements were intended to support the following objectives: to characterize the spatial and temporal variability in BC concentrations and emissions in the border region, to identify potential source areas of BC emissions, and to characterize the cross-border transport of BC and assess its impact on local and regional air quality. BC concentrations at Parque Morelos, the campaign's supersite, averaged 2.1 ?g m?? and reached a maximum value of 55.9 ?g m??. This average value is comparable to levels in large American cities like Los Angeles and similarly sized Mexican cities like Mexicali. The maximum value occurred near midnight, and similar incidents were observed on nearly half of the overnight monitoring periods. BC and carbon monoxide (CO) were strongly correlated at the Mexican sites. The BC/CO ratio was ~3 times higher in Tijuana than in Mexico City, suggesting that gasoline-powered vehicles in Tijuana emit more BC than is typical or that diesel vehicles comprise a relatively high proportion of the vehicle fleet. Tijuana's emissions of BC are estimated to be 380-1470 metric tons yr??. BC measurements were used in conjunction with modeled wind fields to simulate forward and backward particle trajectories. Generally, BC in Tijuana appears to originate locally, as backward simulations showed transport from the US into Mexico at only one site. The majority of the trajectory analyses indicate that there is often transport from Tijuana into the US, crossing the border in a northeasterly direction to the east of San Diego-Tijuana and sometimes as far east as Imperial County at the eastern edge of California. These results suggest that any air quality management strategies considering BC should account for contributions from the border region, as BC is chemically inert in the atmosphere and can travel up to thousands of kilometers. / Master of Science

Soil organic matter (SOM) plays an important role in the global carbon cycle. Therefore, it is important to understand the stability of SOM, which is related to several processes. Its intrinsic properties may be related to its stability, for example black carbon is considered to be relatively resistant to degradation. In most soils, the dark horizons coincide with the superficial layers or horizons due to the greater accumulation of organic matter, but in the southern states of Brazil, the presence of soils with dark subsurface horizons is frequently observed. The dark subsurface horizon of these soils are similar to a sombric horizon. Aspects about its origin, formation and preservation have not yet been fully elucidated. The objective of this work is to understand the formation of \'sombric\' horizons in soils of the region from Tijucas do Sul (Paraná, Brazil). Five soil profiles were described and collected, from which three originate from a toposequence and contained a \'sombric\' horizon (P1-P3), a reference soil that is representative of the area (P5) and an intermediate soil (P4) that showed morphology between the reference soil and the soils with a \'sombric\' horizon. To this end SOM is studied for its molecular composition by the pyrolysis technique coupled to gas chromatography and mass spectrometry (pyrolysis-GC-MS). In addition, 13C isotopic composition (δ13C) and phytolytic composition were studied in order to understand paleoclimatic conditions. These results will be related to past environmental conditions using 14C dating techniques, and supported by classical soil analysis. The samples of the horizons were submitted to the SOM chemical fractionation, generating two fractions: extractable fraction with NaOH (EXT) and residue (RES). The morphology of the profiles showed an intense biological activity in A horizons and a wide distribution of microfragments of charcoals. The lateral continuity of \'sombric\' horizons in toposequence soils was also observed, which differentiated them (P1-P3) from buried A horizons. The distribution of SOM in the fractions studied was the same for the five profiles studied: EXT> RES. Products related to wildfires such as polyaromatics (PAHs; BC) were found in all profiles, but in greater relative abundance in the \'sombric\' horizons, indicating a higher incidence of fire during the formation of these horizons and these compounds can be related to the maintenance of dark color of the \'sombric\' horizons. In relation to the paleoclimatic conditions it was observed that the dark subsurface horizons were developed during the Mid-Holocene under vegetation composed mainly by C4 grasses with shrubs, evidencing a drier climate corresponding to a higher fire incidence. / A matéria orgânica do solo (MOS) desempenha um papel importante no ciclo global do carbono. Portanto, é importante entender a estabilidade da MOS, que está relacionada a vários processos. As suas propriedades intrínsecas podem estar relacionadas com a sua estabilidade, por exemplo, o \"black carbon\" é considerado relativamente resistente à degradação. Na maioria dos solos, os horizontes escuros coincidem com as camadas ou horizontes superficiais devido ao maior acúmulo de matéria orgânica, mas nos estados do sul do Brasil, a presença de solos com horizontes subsuperficiais escurecidos é frequentemente observada. O horizonte subsuperficial escurecido destes solos assemelha-se a um horizonte sômbrico. Aspectos sobre sua origem, formação e preservação ainda não foram totalmente elucidados. O objetivo deste trabalho é compreender a formação de horizontes \'sômbricos\' em solos da região de Tijucas do Sul (Paraná, Brasil). Foram descritos e coletados cinco perfis de solo, dos quais três estão localizados em uma topossequência e continham um horizonte similar ao sômbrico (P1-P3), um solo de referência representativo da área (P5) e um solo intermediário (P4) que apresentou uma morfologia entre o solo de referência e os solos com horizonte \'sômbrico\'. Para este fim, a MOS foi estudada pela sua composição molecular através da técnica de pirólise acoplada à cromatografia gasosa e espectrometria de massa (pirólise-GC-MS). Além disso, estudou-se a composição isotópica 13C (δ 13C) e a composição fitolítica, a fim de compreender as condições paleoclimáticas que foram relacionados com as condições ambientais passadas usando técnicas de datação com 14C, e suportados pelas análises clássicas de solo. As amostras dos horizontes foram submetidas ao fracionamento químico MOS, gerando duas frações: fração extraível com NaOH (EXT) e resíduo (RES). A morfologia dos perfis mostrou uma intensa atividade biológica nos horizontes A e uma ampla distribuição de microfragmentos de carvão. Observouse também a continuidade lateral de horizontes \'sômbricos\' em solos da topossequência (P1-P3), diferenciando-os dos horizontes A enterrados. A distribuição da MOS nas frações estudadas pela pirólise foi a mesma para os cinco perfis: EXT> RES. Os produtos relacionados a incêndios florestais como os poliaromáticos (PAHs, BC) foram encontrados em todos os perfis, mas em maior abundância relativa nos horizontes sômbricos, indicando uma maior incidência de incêndio durante a formação destes horizontes. Os PAHs podem estar relacionados com a manutenção da cor escura dos horizontes \'sômbricos\'. Em relação às condições paleoclimáticas observou-se que os horizontes subsuperficiais escurecidos foram desenvolvidos durante o Holoceno Médio sob vegetação composta principalmente por gramíneas C4 com arbustos, evidenciando um clima mais seco correspondente a maior incidência de incêndio.

Soil organic matter (SOM) plays an important role in the global carbon cycle. Therefore, it is important to understand the stability of SOM, which is related to several processes. Its intrinsic properties may be related to its stability, for example black carbon is considered to be relatively resistant to degradation. In most soils, the dark horizons coincide with the superficial layers or horizons due to the greater accumulation of organic matter, but in the southern states of Brazil, the presence of soils with dark subsurface horizons is frequently observed. The dark subsurface horizon of these soils are similar to a sombric horizon. Aspects about its origin, formation and preservation have not yet been fully elucidated. The objective of this work is to understand the formation of \'sombric\' horizons in soils of the region from Tijucas do Sul (Paraná, Brazil). Five soil profiles were described and collected, from which three originate from a toposequence and contained a \'sombric\' horizon (P1-P3), a reference soil that is representative of the area (P5) and an intermediate soil (P4) that showed morphology between the reference soil and the soils with a \'sombric\' horizon. To this end SOM is studied for its molecular composition by the pyrolysis technique coupled to gas chromatography and mass spectrometry (pyrolysis-GC-MS). In addition, 13C isotopic composition (δ13C) and phytolytic composition were studied in order to understand paleoclimatic conditions. These results will be related to past environmental conditions using 14C dating techniques, and supported by classical soil analysis. The samples of the horizons were submitted to the SOM chemical fractionation, generating two fractions: extractable fraction with NaOH (EXT) and residue (RES). The morphology of the profiles showed an intense biological activity in A horizons and a wide distribution of microfragments of charcoals. The lateral continuity of \'sombric\' horizons in toposequence soils was also observed, which differentiated them (P1-P3) from buried A horizons. The distribution of SOM in the fractions studied was the same for the five profiles studied: EXT> RES. Products related to wildfires such as polyaromatics (PAHs; BC) were found in all profiles, but in greater relative abundance in the \'sombric\' horizons, indicating a higher incidence of fire during the formation of these horizons and these compounds can be related to the maintenance of dark color of the \'sombric\' horizons. In relation to the paleoclimatic conditions it was observed that the dark subsurface horizons were developed during the Mid-Holocene under vegetation composed mainly by C4 grasses with shrubs, evidencing a drier climate corresponding to a higher fire incidence. / A matéria orgânica do solo (MOS) desempenha um papel importante no ciclo global do carbono. Portanto, é importante entender a estabilidade da MOS, que está relacionada a vários processos. As suas propriedades intrínsecas podem estar relacionadas com a sua estabilidade, por exemplo, o \"black carbon\" é considerado relativamente resistente à degradação. Na maioria dos solos, os horizontes escuros coincidem com as camadas ou horizontes superficiais devido ao maior acúmulo de matéria orgânica, mas nos estados do sul do Brasil, a presença de solos com horizontes subsuperficiais escurecidos é frequentemente observada. O horizonte subsuperficial escurecido destes solos assemelha-se a um horizonte sômbrico. Aspectos sobre sua origem, formação e preservação ainda não foram totalmente elucidados. O objetivo deste trabalho é compreender a formação de horizontes \'sômbricos\' em solos da região de Tijucas do Sul (Paraná, Brasil). Foram descritos e coletados cinco perfis de solo, dos quais três estão localizados em uma topossequência e continham um horizonte similar ao sômbrico (P1-P3), um solo de referência representativo da área (P5) e um solo intermediário (P4) que apresentou uma morfologia entre o solo de referência e os solos com horizonte \'sômbrico\'. Para este fim, a MOS foi estudada pela sua composição molecular através da técnica de pirólise acoplada à cromatografia gasosa e espectrometria de massa (pirólise-GC-MS). Além disso, estudou-se a composição isotópica 13C (δ 13C) e a composição fitolítica, a fim de compreender as condições paleoclimáticas que foram relacionados com as condições ambientais passadas usando técnicas de datação com 14C, e suportados pelas análises clássicas de solo. As amostras dos horizontes foram submetidas ao fracionamento químico MOS, gerando duas frações: fração extraível com NaOH (EXT) e resíduo (RES). A morfologia dos perfis mostrou uma intensa atividade biológica nos horizontes A e uma ampla distribuição de microfragmentos de carvão. Observouse também a continuidade lateral de horizontes \'sômbricos\' em solos da topossequência (P1-P3), diferenciando-os dos horizontes A enterrados. A distribuição da MOS nas frações estudadas pela pirólise foi a mesma para os cinco perfis: EXT> RES. Os produtos relacionados a incêndios florestais como os poliaromáticos (PAHs, BC) foram encontrados em todos os perfis, mas em maior abundância relativa nos horizontes sômbricos, indicando uma maior incidência de incêndio durante a formação destes horizontes. Os PAHs podem estar relacionados com a manutenção da cor escura dos horizontes \'sômbricos\'. Em relação às condições paleoclimáticas observou-se que os horizontes subsuperficiais escurecidos foram desenvolvidos durante o Holoceno Médio sob vegetação composta principalmente por gramíneas C4 com arbustos, evidenciando um clima mais seco correspondente a maior incidência de incêndio.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / O manto polar antártico retêm informação paleoclimatologica por entres suas camadas de neve e gelo. O gelo antártico tem revelado a base de dados paleoclimática de maior resolução para os últimos 800 mil anos. Os padrões de transporte atmosférico refletem a composição e a fonte do particulado encontrado na neve e no gelo do continente Antártico. Estando relacionado a processos climáticos, as características desse transporte alteram em quantidade e qualidade as espécies químicas que se depositam sobre o manto de gelo. Dessa forma, o estudo dos depósitos de particulado ao longo das camadas de neve/gelo na Antártica pode sugerir mudanças nos padrões de transporte atmosférico. Atualmente a comunidade científica discute as diferenças de padrões climáticos entre o leste e o oeste antártico. Enquanto de forma geral observa-se instabilidade no setor oeste, o clima da antártica oriental demonstra relativa estabilidade climática. Neste estudo, analisamos dois testemunhos de gelo recente de duas regiões com características climáticas diferentes do continente Antártico. No Platô Detroit situado na Península Antártica (6410′S/0600′O), analisamos a variabilidade de Black Carbon (BC) ao longo de 20 metros de neve. O BC encontrado na Península Antártica apresentou baixas concentrações comparáveis as encontradas no gelo do Artico período pré-industrial. Nossos resultados sugerem que sua variabiliade corresponde à sazonalidade dos períodos de queimada nos continentes do Hemisfério Sul. No interior do continente Antártico, analisamos o particulado em geral por um processo de microanálise ao longo de um testemunho de 40 metros extraído em Mont Johns (79o55′S/09423′O). Encontramos uma tendência negativa na deposição de poeira mineral (AlSi) entre 1967 e 2007. Nossos resultados sugerem que esta tendência seja resultado de um crescente isolamento atmosférico da região central do continente antártico pelo aumento da intensidade dos ventos ao redor da Antártica. Este aumento na intensidade dos ventos reflete por sua vez o resfriamento da alta atmosfera no centro antártico causado pela depleção da camada de ozônio na região. Adicionalmente, amostras de diferentes microambientes de Patriot Hills (8018′S/08121′O) foram coletadas de maneira asséptica para análise microbiológica. As amostras foram cultivadas em meio R2 e paralelamente o DNA total extraído foi sequenciado pela técnica de pirosequenciamento. Os resultados preliminares desta analise mostram grande riqueza de espécies dos mais variados grupos. Os resultados deste trabalho caracterizam três diferentes parâmetros relacionados a deposição atmosférica em duas áreas pouco exploradas e de grande interesse científico do continente antártico. / The antarctic ice cap stores paleoclimatological information within layers of snow and ice. Antarctic ice has revealed the higher resolution paleoclimactic database for the last 800 kyr. Atmospheric transport plays a fundamental role on the composition and sources of particulate matter found in the Antarctic ice. It has been related to several climatic processes that changes the quantity and quality of exogenous aerosols reaching Antarctica. Therefore, studies of the particulate matter deposits along the snow/ice layers may suggest changes on atmospheric transport patterns. This work, analyze two recent ice cores from two climatic distinct regions of the Antarctic continent. One retrieved from Detroit Plateau/Antarctic Peninsula (6410′S/0600′W), in which we have analyze Black Carbon (BC) deposition and variability along 20 meters of snow. BC found in the Antarctic Peninsula showed low concentrations (varing between 0,014 and 3,733ppb), comparable to the concentrations found on Arctic ice dated from before the industrial revolution period. Our results suggest that peaks of BC detected correspond, mostly, to biomass burning seasons in the South Hemisphere, not speficically from South America. The second one, of 40 m, was retrieved from Central-West Antarctica, Mont Johns (79o55′S/094 23′W), in which we analyzed the mineral dust abundance thought M.E.V. E.D.X. technique. In this study we found negative trends in mineral dust (inferred from Fe, Ti and AlSi) deposition between 1967 and 2007, in contrast to similar works in Sub-antarctic regions. We demonstrate that this trend is a consequence of the persistent atmospheric isolation that encloses the Central and East Antarctic regions due to the increasing winds around Antarctica within this period. It has been documented that westerlies intensification reflect the upper atmosphere cooling above Central Antarctica caused by the stratospherical ozone layer depletion. As part of the polar site characterization, we additionally have performed sampling for microbiological purpose from distinct microenvironments at Patriot Hills (8018′S/08121′W). Samples were cultivated on R2 media and at the same time total DNA on samples was extracted and sent to a pyrosequencing analysis. Preliminary results show richness and diversity of bacterial species distributed on five phyla.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / O manto polar antártico retêm informação paleoclimatologica por entres suas camadas de neve e gelo. O gelo antártico tem revelado a base de dados paleoclimática de maior resolução para os últimos 800 mil anos. Os padrões de transporte atmosférico refletem a composição e a fonte do particulado encontrado na neve e no gelo do continente Antártico. Estando relacionado a processos climáticos, as características desse transporte alteram em quantidade e qualidade as espécies químicas que se depositam sobre o manto de gelo. Dessa forma, o estudo dos depósitos de particulado ao longo das camadas de neve/gelo na Antártica pode sugerir mudanças nos padrões de transporte atmosférico. Atualmente a comunidade científica discute as diferenças de padrões climáticos entre o leste e o oeste antártico. Enquanto de forma geral observa-se instabilidade no setor oeste, o clima da antártica oriental demonstra relativa estabilidade climática. Neste estudo, analisamos dois testemunhos de gelo recente de duas regiões com características climáticas diferentes do continente Antártico. No Platô Detroit situado na Península Antártica (6410′S/0600′O), analisamos a variabilidade de Black Carbon (BC) ao longo de 20 metros de neve. O BC encontrado na Península Antártica apresentou baixas concentrações comparáveis as encontradas no gelo do Artico período pré-industrial. Nossos resultados sugerem que sua variabiliade corresponde à sazonalidade dos períodos de queimada nos continentes do Hemisfério Sul. No interior do continente Antártico, analisamos o particulado em geral por um processo de microanálise ao longo de um testemunho de 40 metros extraído em Mont Johns (79o55′S/09423′O). Encontramos uma tendência negativa na deposição de poeira mineral (AlSi) entre 1967 e 2007. Nossos resultados sugerem que esta tendência seja resultado de um crescente isolamento atmosférico da região central do continente antártico pelo aumento da intensidade dos ventos ao redor da Antártica. Este aumento na intensidade dos ventos reflete por sua vez o resfriamento da alta atmosfera no centro antártico causado pela depleção da camada de ozônio na região. Adicionalmente, amostras de diferentes microambientes de Patriot Hills (8018′S/08121′O) foram coletadas de maneira asséptica para análise microbiológica. As amostras foram cultivadas em meio R2 e paralelamente o DNA total extraído foi sequenciado pela técnica de pirosequenciamento. Os resultados preliminares desta analise mostram grande riqueza de espécies dos mais variados grupos. Os resultados deste trabalho caracterizam três diferentes parâmetros relacionados a deposição atmosférica em duas áreas pouco exploradas e de grande interesse científico do continente antártico. / The antarctic ice cap stores paleoclimatological information within layers of snow and ice. Antarctic ice has revealed the higher resolution paleoclimactic database for the last 800 kyr. Atmospheric transport plays a fundamental role on the composition and sources of particulate matter found in the Antarctic ice. It has been related to several climatic processes that changes the quantity and quality of exogenous aerosols reaching Antarctica. Therefore, studies of the particulate matter deposits along the snow/ice layers may suggest changes on atmospheric transport patterns. This work, analyze two recent ice cores from two climatic distinct regions of the Antarctic continent. One retrieved from Detroit Plateau/Antarctic Peninsula (6410′S/0600′W), in which we have analyze Black Carbon (BC) deposition and variability along 20 meters of snow. BC found in the Antarctic Peninsula showed low concentrations (varing between 0,014 and 3,733ppb), comparable to the concentrations found on Arctic ice dated from before the industrial revolution period. Our results suggest that peaks of BC detected correspond, mostly, to biomass burning seasons in the South Hemisphere, not speficically from South America. The second one, of 40 m, was retrieved from Central-West Antarctica, Mont Johns (79o55′S/094 23′W), in which we analyzed the mineral dust abundance thought M.E.V. E.D.X. technique. In this study we found negative trends in mineral dust (inferred from Fe, Ti and AlSi) deposition between 1967 and 2007, in contrast to similar works in Sub-antarctic regions. We demonstrate that this trend is a consequence of the persistent atmospheric isolation that encloses the Central and East Antarctic regions due to the increasing winds around Antarctica within this period. It has been documented that westerlies intensification reflect the upper atmosphere cooling above Central Antarctica caused by the stratospherical ozone layer depletion. As part of the polar site characterization, we additionally have performed sampling for microbiological purpose from distinct microenvironments at Patriot Hills (8018′S/08121′W). Samples were cultivated on R2 media and at the same time total DNA on samples was extracted and sent to a pyrosequencing analysis. Preliminary results show richness and diversity of bacterial species distributed on five phyla.

Les HAP contaminent de nombreux sols de friches industrielles. Leur dissipation par biodégradation est limitée par leur faible disponibilité. Nous avons étudié les facteurs contrôlant cette disponibilité dans les sols ainsi que les variables rhizosphériques qui la font varier. Nous avons préalablement défini que la disponibilité des HAP pouvait être estimée par une extraction en 30 heures sur une résine adsorbante, le Tenax®. Ce protocole a permis de comparer la disponibilité dans trois sols de friche et de déterminer les facteurs de contrôle de celle-ci. Le premier facteur est le diamètre des particules de black carbon qui sont la matrice porteuse de HAP. Ensuite, l’intensité d’agrégation par l’intermédiaire de ciments carbonatés est le deuxième facteur de contrôle important de la disponibilité des HAP. Des expériences de laboratoire ont montré que la disponibilité des HAP peut être influencée par des variables rhizosphériques. Ainsi, l’acidification d’un sol calcaire permet la dissolution des ciments carbonatés et augmente la disponibilité des HAP du fait de la désagrégation. L’alcalinisation quant à elle, augmente la disponibilité en diminuant les forces de sorption et parfois en décondensant la phase organique porteuse de HAP. En plus de son rôle acidifiant, l’acide citrique par ses propriétés complexantes permet d’augmenter la disponibilité des HAP de 40%. Les paramètres modifiés artificiellement au laboratoire ne sont pas toujours aussi facilement contrôlable in situ. Dans des expériences de terrain, nous avons vu qu’une alcalinisation artificielle du sol entraînait l’accroissement de la vitesse de dissipation des HAP. La culture de lupin blanc connu pour exsuder de l’acide citrique dans sa rhizosphère, a permis l’augmentation significative de la dissipation de l’anthracène, résultat très encourageant compte-tenu de la courte durée de culture et la relative phytotoxicité des sols étudiés / PAHs are present in many industrial wasteland soils. Their remediation using biological techniques remains limited because of their low availability. This work identifies some of the factors controlling this availability in soil and proposes management strategies able to modify it, focusing on plant assisted treatment. First, we have shown that PAHs availability can be estimated by a 30 hours extraction using a Tenax® resin. The analysis of PAHs availability for three wasteland soils showed that the size of black carbon particles, which is the main PAHs reservoir, and the aggregation intensity are the two main availability controlling factors. Laboratory experimentation also showed that this availability can be influenced by rhizosphere parameters. Acidification of a calcareous soil, in dissolving the carbonated cement, can increase PAHs availability by desaggregation. Soil alkalinisation, in decreasing sorption forces between PAHs and the solid matrix, may also increase availability. Citric acid has an effect even more pronounced than the pH alone. Its chelating properties can increase PAHs availability by 40%. Some of these laboratory results have been confirmed by in situ experiments. Indeed, a white lupine culture was able to increase anthracene dissipation for one of the tested wasteland soil over a 5 months period

This thesis deals with black carbon, its characteristic features and with its occurrence in chernozemic soils. In particular, this thesis deals with methods, which can study presence of black carbon in soils. The presence of black carbon and the whole composition of soil organic matter of three chernozemic soils in Czechia (Zeměchy, Tursko, Syrovice) is examined by 13 C NMR spectroscopy. Anthracological analysis of charcoal from fossil chernozems of Zemechy loess ravine deals with pedogenesis of chernozems and development of Quaternary vegetation in Central Europe. Coniferous tree species of Pinus sp., Pinus cf. cembra, Larix/Picea, Juniperus a Vaccicium, i.e. cold- and drought-tolerant taxa, were identified by anthracological analysis of soils of Zemechy loess ravine. The identified species suggest that the landscape around Zemechy was probably formed by parkland taiga. According to 13 C NMR spectroscopy, soil organic matter of fossil chernozem of Zemechy loess ravine consists particularly of alkyl and O-alkyl carbon. Aromatic carbon is also significant. O-alkyl carbon is the most important in the recent chernozems of Tursko and Syrovice. Aromatic carbon has the smallest proportion in both chernozems. The presence of aromatic carbon in chernozem of Tursko is the smallest of all analyzed soils. The...

Bacteria secrete and sense extracellular signals from neighboring members of a colony in a phenomenon called quorum sensing. These signals vary from species to species but allow for changes in the behavior of a colony based on changes to cell density, environment, or nutrient supply. Of particular interest to human health is the quorum sensing system of Streptococcus pneumoniae as this pathogen accounts for around one million infection-related deaths per year and is difficult to combat largely due to its ability to form biofilms. These polysaccharide coverings protect entire bacterial colonies from antimicrobial agents as well as allow them to adhere well to the nasopharynx passages of organisms, making them hard to remove. To gain a better understanding of quorum sensing in S. pneumoniae, we propose experiments to study its biofilm formation and its interactions with black carbon, a biochar shown previously to interact with the quorum sensing systems of related bacteria species. We hypothesize that inhalation of black carbon will aggravate a S. pneumoniae infection by promoting biofilm-forming quorum sensing systems making it easier for this bacteria to adhere to and remain on mammal lungs. We propose to first explore the competency and biofilm quorum sensing systems in S. pneumoniae to identify any shared signals between the two using RT-PCR and FITC-Dextran experiments. Further experiments will analyze black carbon particles’ effects on bacterial colonies grown on plates and present on the lung linings of mammals.