Made available in DSpace on 2014-10-09T12:42:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:53Z (GMT). No. of bitstreams: 0 / Radiofármacos são preparações farmacêuticas que possuem um radionuclídeo em sua composição. Cerca de 95% deles são utilizados com finalidade diagnóstica e em sua maioria são administrados por via parenteral, requerendo o uso de água purificada (AP) e para injeção (API) nos processos de produção, controle de qualidade e pesquisa de novos radiofármacos. A produção de radiofármacos no Brasil deve atender às Boas Práticas de Fabricação (BPF), RDC n. 17/2010 e RDC n. 63/2009 da ANVISA e requisitos de qualidade definidos pelas farmacopeias vigentes. Considerando que os volumes dos lotes de fabricação de radiofármacos são reduzidos, de algumas dezenas a centenas de mililitros, e a sua validade é de algumas horas a alguns dias, frequentemente tem sido utilizados sistemas purificadores de uso laboratorial para a produção de AP e API nas radiofarmácias. A determinação de carbono orgânico total (COT) é um dos requisitos a serem atendidos na avaliação da qualidade de AP e API e o seu limite é de 500 μg L-1. O objetivo deste estudo foi validar o método analítico de COT que combina reações de acidificação e de oxidação química do carbono para análise de carbono inorgânico (CI) e carbono total (CT), na análise de AP e API, avaliar o desempenho de sistemas de purificação de uso laboratorial para a produção de AP e API e comparar com a API adquirida de fornecedores externos. Utilizou-se um analisador de carbono modelo TOC-Vwp acoplado a um amostrador automático modelo ASI-V, ambos da marca Shimadzu® e controlados por software TOC Control-V e frascos de 40 mL lavados com HNO3 15%, com soluções de reagente oxidante (Na2S2O8 0,5 mol L-1) e acidificante (H3PO4 3,0 mol L-1), soluções de COT/CT (C8H5O4K) e CI (Na2CO3 e NaHCO3) nas concentrações 100-1000 μg L-1. Foram avaliados os parâmetros de validação de método: conformidade do sistema, robustez, repetibilidade, precisão intermediária, exatidão, linearidade e limites de detecção e quantificação. O desempenho de 5 sistemas de purificação foram avaliados, com amostragem de AP e API de 6 pontos (3 de AP e 3 de API) e foram analisados COT, condutividade, pH, contagem de aeróbios totais e endotoxina bacteriana (somente para API). As melhores condições de análise foram 2 mL de oxidante, 3% de acidificante, tempo de integração da curva de CT de 10 minutos e 3 minutos para CI. As curvas analíticas de CT e CI foram lineares nas faixas de concentrações analisadas, com a soma residual dos mínimos quadrados (r2) maior que 0,997. Os resultados de repetibilidade apresentaram valores entre 0,40 4,40%, a precisão intermediária por sua vez apresentou a seguinte variação, 0,65 a 4,63% e exatidão apresentou valores na faixa de 96,76-112,52%. Os limites de detecção (LD) e quantificação (LQ) foram 31,83 e 106,11 μg L-1 e 59,16 e 197,22 μg L-1, para CT e CI, respectivamente. A avaliação de desempenho dos purificadores indicam que um procedimento adequado de limpeza do reservatório de água é importante para manter a concentração de COT em cerca de 100 μg L-1. A análise de COT/CI pode ser utilizada como indicador da necessidade de manutenção do sistema purificador. Algumas API embaladas apresentaram COT acima de 500 μg L-1. O monitoramento de COT durante a avaliação de desempenho dos sistemas de uso laboratorial acoplados a reservatórios indicou que eles são equipamentos adequados para obtenção de AP e API em radiofarmácia. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Legacy mine sites are of concern due to their prevalence and associated environmental and human health risks. The United States Bureau of Land Management estimates as many as 500,000 abandoned mine sites in the US (BLM, 2017). Sites requiring costly management and long-term response to the environmental hazardous risks can be designated to a National Priority List (NPL) by the Environmental Protection Agency (EPA) under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) (EPA, 2017). One such site, located in Central Arizona, is the Iron King Mine Humboldt Smelter Superfund Site (IKMHSSS). The site was designated to the NPL in 2008 due to concerns regarding the size of the tailing pile, the proximity of contaminated materials to the town of Dewey-Humboldt and waterways, and the dangerous concentrations of arsenic (As) and lead (Pb) of the tailings (EPA, 2017). Remediation efforts have been ongoing since the designation of the site to the NPL, including sampling, yard soil removal, and distribution of information to the local community regarding risks from the site. The University of Arizona Superfund Research Program (UA SRP) has conducted greenhouse and phytostabilization studies of the site in an attempt to understand the processes and mechanisms employed to stabilize the tailings materials as well as reduce dust emissions from the tailings to the town of Dewey-Humboldt (Gil-Loaiza et al., 2016). This effort has successfully demonstrated a reduction of dust emissions (Sáez, 2016), however chemical changes to the tailings due to phytostabilization are the focus of this research. This work attempts to ascertain whether adverse effects from the method of phytostabilization are observed in the pore waters of the tailing material, in particular the potential for contamination of water sources by mobilized As through chemical or microbiological means. Recent studies have proposed potential mechanisms that can promote mobilization of As by dissolved organic matter (DOM) (Mladenov et al., 2015). Heterotrophic microbial respiration under O2 limited conditions can cause the reduction of Fe3+ to Fe2+, enhancing desorption or dissolution of As from Fe containing minerals (Hasan et al., 2007). Additionally, DOM competes with As for sorption sites at mineral surfaces (Grafe et al., 2002). In this study, batch and column experiments were used to investigate the mechanisms of sequestration and release of As in compost amended mine tailings. Mine tailings were reacted in triplicate in the presence and absence of DOM using plain tailings and radiated tailings for microbiological control and under anoxic and oxic conditions at timescales from ranging from 3 to 900 hours for batch experiments and 1 to 900 pore volumes in column experiments. The highest As release to pore waters was observed under anoxic conditions in the presence of DOM both with microbial activity inhibited and uninhibited through 60Co gamma irradiation after 3 and 910 h of reaction. The release of As from batch experiments was lowest in the control treatment with no DOM added to tailings in both anoxic and oxic treatments after 24 h. Column flow-through experiments were also carried out to better understand the kinetic biogeochemistry of the tailings interacting with DOM. Columns were completed under suboxic conditions to best mimic field scenarios. To test the effect of microbes, control tailing samples were sterilized by 60Co gamma irradiation prior to flowing DOM. Pore volumes (PV) were collected using fractionation equipment from 1 to 900 PVs. The release of As was highest in the presence of DOM after approximately 40 PVs when As release began increasing to its maximum release of 50 μmol l-1. No significant difference between irradiated and non-irradiated tailings was observed in either irradiated or non-irradiated tailings. Lowest release of As to effluent solutions was in the absence of DOM. These results were consistent with the findings from batch experiments. Batch and column experiments show that DOM influences the mobilization of As from mine tailings, and demonstrates the potential risk to proximal ground water resources in the absence of attenuation processes between the oxidized tailings and groundwater.

Master of Science / Department of Geology / Saugata Datta / Elevated levels of dissolved arsenic (As), iron (Fe) and manganese (Mn) are seen in the shallow, anoxic groundwaters of southeast Bangladesh on the Ganges- Brahmaputra- Meghna River delta. Over the past decade the mechanisms of As release have been widely debated. It is understood that As can sorb onto Fe-bearing minerals and can be subsequently released when reactions, such as microbially driven processes, occur. This study takes a multi disciplinary approach to understand the extent of the natural reactive barrier along the Meghna River and to evaluate the role of the natural reactive barrier in As sequestration and release in groundwater aquifers. River water and groundwater interactions occur in the hyporheic zone, which is defined as the transient subsurface region where river water and groundwater mix. The natural reactive barrier can develop within the hyporheic zone, where Fe-bearing minerals accumulate with a potential for As sorption, along with reworking and re-deposition of sediments along the riverbank. Shallow sediment cores, and groundwater and river water samples were collected from the east and west banks of the Meghna River in Jan. 2016. Groundwater and river water samples were tested for total dissolved Fe, Mn, and As concentrations; δ₂H, δ₁₈O isotopic ratios. Fluorescence spectroscopic characterization of groundwater organic matter provided insight into the hydro-geochemical reactions active in the groundwater and the hyporheic zone. Eight sediment cores of ~1.5 m depth were collected ~10 m away from the edge of the river. Vertical solid-phase concentration profiles of Fe, Mn, and As were measured by four different methods (hand-held XRF, and ICP-OES analysis of 3 digestions: aquaregia (HNO₃: HCl 1:3), 1.2 M HCl, and 1 M NaH₂PO₄ + 1 M L-ascorbic acid extractions). Enrichment of solid phase Fe, Mn, and As and the presence of possible Fe and Mn oxides in the sediments illustrate the existence of an natural reactive barrier at this reach of the Meghna. HCl extractions of sediment revealed solid-phase As accumulation along the west riverbank reaching concentrations of ~1500 mg/kg. Aqueous geochemical results showed the highest dissolved As concentrations in shallow wells (<30 m depth), where organic matter was fresh, humic-like, and aromatic. Humic-like dissolved organic matter present in the groundwater may enhance Fe oxide dissolution. Microbial reduction of organic matter prompts the reduction of Fe³⁺ to Fe²⁺, causing As to mobilize into groundwater. This study quantified the extent of As accumulation in the sediments along a 1 km stretch of the Meghna River. These findings contribute to the understanding of geochemical processes involved in As release into groundwaters from sediments within a fluvial deltaic environment.

Magister Scientiae - MSc / The primary origin of this project is due to a high demand for freshwater supply in the Berg Water Management Area (WMA). Most of the Berg WMA`s freshwater supply does not live up to the high ecological standards. This is mainly due to high sediments loading in the Berg River which is one of the water supplies to the Berg WMA. The project was conducted on a small-scale catchment at Langgewens experimental farms in Swartland district. The focus of this study was to address some of the hydrological processes active in the research catchment: infiltration, run-off and sediment mobilization on different soil types under wheat and canola vegetation cover. This was done to investigate the origin of sediments in the Berg River. Considering the results, one might conclude that the decayed root systems from the canola and wheat vegetation covers, organic matter content, soil cracks, slope orientation, and soil composition, all played a major role in influencing the ability of the soil to absorb the simulated rainfall. Because the infiltration was calculated using the difference between the incoming simulated rainfall and the measured run-off, there was an inverse relationship between run-off and infiltration. When run-off was low, the infiltration was high and vice versa. iv Factors that governed sediment mobilisation within the ring area are micro topography within the ring area, the slope gradient and vegetation covers. Considering the results, vegetation cover played a pivotal role and it must be maintained at all times. It is advisable that the land users leave crop residual cover behind after the annual harvest and not expose the land surface in bare form for too long as this will generate more run-off and increase sediment mobilisation. The analyses showed that wheat crop protects the soil from rain drop impact than on canola crop.

De nombreux déchets organiques urbains, industriels et agricoles sont considérés comme des produits résiduaires organiques (PRO). Ils sont potentiellement recyclables en agriculture comme amendement ou fertilisant pour le sol avec selon le type de déchet la mise en œuvre de traitements biologiques (digestion anaérobie, compostage). Du fait de l'utilisation de produits chimiques, les PRO contiennent des micropolluants organiques (µPO) particulièrement quantifiés dans les boues d'épuration. Ces µPO peuvent être toxiques pour les humains et les écosystèmes bien que les concentrations dans les milieux aquatiques soient très faibles (ng-µg.L-1). La plupart de ces µPO ont un fort impact sur l'environnement. Lors des traitements biologiques des boues d'épuration, l'élimination des µPO dépend de deux processus (sorption et biodégradation) eux-mêmes contrôlés par les propriétés physicochimiques de la matière organique et des µPO et les microorganismes présents. La forte sorption et le piégeage des µPO ou leur biodégradation dans la matrice boue lors des traitements minimisent le risque de transfert à l'eau ou à la faune/flore après l'épandage des boues. Cette thèse se propose d'étudier le devenir de différents µPO (hydrocarbures aromatiques polycycliques (HAP), nonylphénols (NP) et produits pharmaceutiques) lors du traitement de boues par digestion anaérobie et compostage en lien avec le devenir de la matière organique et l'affinité des µPO pour certaines fractions de cette matière organique. L'objectif est de mieux comprendre les mécanismes qui régissent l'élimination des µPO et in fine d'estimer comment améliorer le procédé pour limiter les transferts au continuum sol/eau/biote. Dans un premier temps, un protocole de caractérisation de la matière organique a été couplé avec un dosage de µPO au cours d'une incubation anaérobie, sur une matrice modèle (boue) et sur des composés modèles (HAP, NP). Les résultats ont montré que les µPO dissipés se situent dans les compartiments les plus accessibles et les plus dégradables de la matière organique et que cette dissipation est pilotée par la dégradation de la matière ; de plus, un phénomène de vieillissement a été observé pour des molécules dopées. Les résultats démontrent que les µPO étudiés ici ont une affinité pour les matières organiques complexes de type humiques. Lors des incubations, seule la moitié de la matière organique est caractérisée. Le protocole de caractérisation de la matière organique a été modifié pour aller plus loin dans la caractérisation « matière » mais aussi en vue d'une application sur la localisation des µPO tout au long d'un système de traitement comprenant digestion et compostage. Ce protocole a donc été revu afin de pouvoir caractériser des matrices de type lignocellulose. Ce protocole a été appliqué à des échantillons issus de la digestion anaérobie et du compostage de boues en laboratoire. Ces procédés sont capables d'éliminer une partie des µPO ; le couplage des deux augmentant le taux d'élimination. L'évolution des fractions matière reflètent la dégradation de la matière organique lors des traitements. De plus, le devenir des µPO étudiés est piloté par le devenir de la matière organique nous permettant de proposer des stratégies d'optimisation de leur dissipation.Les résultats acquis permettent de déterminer des taux d'abattement des µPO lors des traitements des boues mais aucune information n'est donnée quant aux mécanismes précis d'élimination. Les mêmes traitements ont été menés en utilisant des molécules marquées au 14C. Les résultats obtenus sur trois molécules (fluoranthène, NP et sulfaméthoxazole) montrent que les µPO ne sont pas minéralisés lors de la digestion anaérobie. Lors du compostage des boues digérées, une minéralisation du NP apparaît lors de la phase de maturation. Diverses hypothèses peuvent alors expliquer l'élimination constatée au cours des traitements sans molécule marquée : métabolites ou résidus non extractibles sont formés. / Animal manures, urban organic wastes including sewage sludge, food processing and other industrial wastes are considered as organic wastes that are potentially recycled in agriculture as soil amendment or fertilizer after biological treatment like anaerobic digestion and composting.Due to the use of chemicals and industrial activities, these organic wastes contain organic micropollutants, particularly quantified in sewage sludge. These micropollutants are a family of organic compounds which may be toxic for humans or ecosystems even though their concentrations in aquatic environments are usually low (µg to ng.L-1). Most of them have huge impacts on environment (e.g. some of them are endocrine disruptors that can feminize fishes in rivers with concentrations of few ng.L-1).During biological treatments of sewage sludge, micropollutants elimination depends on two processes (sorption and biodegradation) that are driven by physicochemical properties of organic matter and micropollutants and microorganisms. Strong sorption and trapping of organic micropollutants or their biodegradation in sludge matric during anaerobic digestion and composting can minimize their transfer into water or biota after spreading.This thesis aims at studying the fate of organic micropollutants (polycyclic aromatic hydrocarbons (PAHs), nonylphenols (NPs) and pharmaceuticals compounds) during sludge treatment by anaerobic digestion and composting in link with the fate of organic matter and the micropollutants affinity for some organic matter fractions. The objective is to better understand the mechanisms which control the micropollutants elimination and estimate how to improve the process to minimize environmental impact.First, a method for sludge organic matter characterization is coupled to organic micropollutants quantification during a model batch process (anaerobic incubation), on a model matrix (sludge) and model compounds (PAHs, NPs). Results show that dissipated micropollutants are located in more accessible and degradable fraction of organic matter and that dissipation is driven by organic matter degradation; furthermore, ageing phenomenon is observed for spiked compounds. Results show that micropollutants have strong affinity for complex organic matter (humic-like substances).During incubations, the quantity of characterized organic matter corresponds only to 50 % of chemical oxygen demand. A modified protocol for characterizing organic matter is set up to go further on organic matter characterization but also to apply it to localization of organic micropollutants. This protocol is also modified in order to characterize other organic matrices (compost).The new protocol is applied to samples from anaerobic digestion and composting of sludge at lab-scale. Anaerobic digestion and composting are able to eliminate organic micropollutants. Coupling both processes increases micropollutants removal. The fate of organic matter pools during processes mimics the fate of organic matter. A link between the fate of organic matter and the fate of organic micropollutants is determined during anaerobic digestion and composting.The results allow determining organic micropollutants removal during anaerobic digestion and composting of sludge but no information is given about the removal mechanisms. Anaerobic digestion with composting is set up at lab-scale with the use of organic 14C labelled micropollutants. The results with three molecules (fluoranthene, sulfamethoxazole, nonylphenols) show that organic micropollutants are not mineralized during anaerobic digestion. During composting, only nonylphenols are mineralized during the maturation phase. Hypothesis about micropollutants removal are the production of metabolites or the formation of non-extractable residues.

One of the key processes in the carbon cycle on our planet is the degradation of dissolved organic matter (DOM) in aquatic environments. The use of organic matter by bacteria links energy from DOM to higher trophic levels of the ecosystem when bacteria are consumed by other organisms. This is referred to as the microbial loop. In this thesis I examined if the communities were functionally redundant in their ability to utilize organic matter, or if variation in bacterial composition and richness is of importance. To test this overarching question several experiments were conducted that include methods such as illumina sequencing of the 16S rRNA gene for taxonomic identification of bacterial communities, flow cytometry to follow the growth of communities and spectroscopic measurement to describe the composition of the organic matter pool. Initially we demonstrated how to optimally sterilize organic matter for experimental studies in order to preserve its natural complexity. In further experiments we found that bacterial communities are redundant in their utilization of organic matter and can maintain optimal performance towards a range of organic matter pools. Related to this we found that pre-adaptation to organic matter played a small role as communities performed equally well regardless of their environmental history. We saw a small effect of richness and composition of bacterial communities on the efficiency of organic matter use, but conclude that this is of minor importance relative to abiotic factors. Still, we also show that organic matter can put strong selection pressure on bacterial communities with regards to richness and composition. Additionally we found that the supply rate of a carbon compound greatly influenced the energy utilization of the compound, i.e. a higher growth rate can be maintained if substrate is delivered in pulses relative to a continuous flow. Finally we conclude that the variation in bacterial communities is unlikely to have a major influence on carbon cycling in boreal lakes, but to enable a finer understanding, the genetics underlying the carbon utilization needs to be further explored.

Florida is the second leading horticulture state in the United States with a total annual industry sale of over $12 Billion. Due to its competitive nature, agricultural plant production represents an extremely intensive practice with large amounts of water and fertilizer usage. Agrochemical and water management are vital for efficient functioning of any agricultural enterprise, and the subsequent nutrient loading from such agricultural practices has been a concern for environmentalists. A thorough understanding of the agrochemical and the soil amendments used in these agricultural systems is of special interest as contamination of soils can cause surface and groundwater pollution leading to ecosystem toxicity. The presence of fragile ecosystems such as the Everglades, Biscayne Bay and Big Cypress near enterprises that use such agricultural systems makes the whole issue even more imminent. Although significant research has been conducted with soils and soil mix, there is no acceptable method for determining the hydraulic properties of mixtures that have been subjected to organic and inorganic soil amendments. Hydro-physical characterization of such mixtures can facilitate the understanding of water retention and permeation characteristics of the commonly used mix which can further allow modeling of soil water interactions. The objective of this study was to characterize some of the locally and commercially available plant growth mixtures for their hydro-physical properties and develop mathematical models to correlate these acquired basic properties to the hydraulic conductivity of the mixture. The objective was also to model the response patterns of soil amendments present in those mixtures to different water and fertilizer use scenarios using the characterized hydro-physical properties with the help of Everglades-Agro-Hydrology Model. The presence of organic amendments helps the mixtures retain more water while the inorganic amendments tend to adsorb more nutrients due to their high surface area. The results of these types of characterization can provide a scientific basis for understanding the non-point source water pollution from horticulture production systems and assist in the development of the best management practices for the operation of environmentally sustainable agricultural enterprise

Elevated levels of arsenic (As) in soils and water around the world are both a significant human health and environmental hazard. With increasing global water demands, there is a requirement to further the understanding of the biogeochemical cycling of As from soils and sediments. This thesis focussed on exploring the environmental controls on the occurrence and subsequent mobility of As in a range of natural environments. Arsenic was found to undergo mobilisation from both river sediments and upland peats under changing environmental conditions. The transport of As was found to be correlated with both iron (Fe) and organic carbon (OC), however temporal changes in both sediment/soil composition and movement of water through catchments have a important role in controlling the ultimate transport of As within the environment. A range of investigative methods were employed to study the occurrence and mobility of As within the river sediments of the Allier and Loire Rivers (France), including sequential extraction procedures and batch incubation studies. Arsenic was associated with the reducible phases of sediments, indicating the major role of Fe(oxy)hydroxides in the storage of As in river sediments. In addition to the presence of labile As, the rapid release of As was dependent on the initial sediment composition. Temporal changes in sediment composition may therefore play an important role in controlling the movement of As within fluvial systems. The combination of lead (Pb) and strontium (Sr) isotopic analysis with sequential extraction studies of sediments from the Loire and Allier Rivers was able to determine the relative dominance of granites and basalts within the sediments. This approach provided a first order study on which to better understand the mineral origins of the sediments. The analysis of multiple Pb isotopes was able to eliminate possible anthropogenic contribution to contamination within the sediments, confirming the importance of geogenic cycling of As within the rivers. Information on the origin of mineral formation was obtained through 87Sr/86Sr isotopic analysis, with the formation of Fe-minerals not occurring uniformly along the course of the rivers. While the Sr within the sediment phase targeting well-crystallised Fe(oxy)hydroxides was in equilibrium with the sampled river water, the formation of amorphous Fe minerals was likely occurring in waters upstream of the study sites, within the Massif Central. Total concentration profiles peat from two subcatchments within the Peak District (United Kingdom) provided evidence for both the retention and post depositional movement (PDM) of As within the solid phase, dependent on local conditions. For the first time, the partitioning of As was determined within ombrotrophic peat, and found to be in contrast to Pb, with oxidisible As (likely associated with organic matter) dominating, while Pb was found predominantly within the reducible sediment phase. High temporal resolution monitoring of the organic-rich streamwater draining the peat showed the transport of As was variable, with As found largely in the soluble form despite extensive peat erosion. The evidence for PDM, and the subsequent soluble transport of As demonstrated the importance of biogeochemical processes in releasing As from the solid phase. Once mobilised, both the ratio of Fe:OC and the form of Fe were found to be factors controlling transport of As, with the flushing of stored porewaters an important contribution to As transport from the peat. Despite OC-rich waters, the occurrence of high concentrations of Fe may dominate control of As within the aqueous phase. At relatively high (>0.2) Fe:OC ratios, the particle size distribution of As was closely correlated with that of >1um Fe, although the presence of dissolved and colloidal As was found even within these waters. Given the temporal variability of As transport within the streams, knowledge of the mixing order and ratio between Fe, OC, and As within natural waters may be required for prediction of the mobility and ultimate fate of As.

Freshwater ecosystems have been recognized as important components of the global carbon cycle, and the flux of organic matter (OM) from freshwater to marine environments can significantly affect estuarine and coastal productivity. The focus of this study was the assessment of carbon dynamics in two aquatic environments, namely the Florida Everglades and small prairie streams in Kansas, with the aim of characterizing the biogeochemistry of OM. In the Everglades, particulate OM (POM) is mostly found as a layer of flocculent material (“floc”). While floc is believed to be the main energy source driving trophic dynamics in this oligotrophic wetland, not much is known about its biogeochemistry. The objective of this study was to determine the origin/sources of OM in floc using biomarkers and pigment-based chemotaxonomy to assess specific biomass contributions to this material, on a spatial (freshwater marshes vs. mangrove fringe) and seasonal (wet vs. dry) scales. It was found that floc OM is derived from the local vegetation (mainly algal components and macrophyte litter) and its composition is controlled by seasonal drivers of hydrology and local biomass productivity. Photo-reactivity experiments showed that light exposure on floc resulted in photo-dissolution of POC with the generation of significant amounts of both dissolved OM (DOM) and nutrients (N & P), potentially influencing nutrient dynamics in this ecosystem. The bio-reactivity experiments determined as the amount and rate of CO2 evolution during incubation were found to vary on seasonal and spatial scales and were highly influenced by phosphorus limitation. Not much is known on OM dynamics in small headwater streams. The objective of this study was to determine carbon dynamics in sediments from intermittent prairie streams, characterized by different vegetation cover for their watershed (C4 grasses) vs. riparian zone (C3 plants). In this study sedimentary OM was characterized using a biomarker and compound specific carbon stable isotope approach. It was found that the biomarker composition of these sediments is dominated by higher plant inputs from the riparian zone, although inputs from adjacent prairie grasses were also apparent. Conflicting to some extent with the River Continuum Concept, sediments of the upper reaches contained more degraded OM, while the lower reaches were enriched in fresh material deriving from higher plants and plankton sources as a result of hydrological regimes and particle sorting.

Orientadores: Zigomar Menezes de Souza, João Luís Nunes Carvalho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-28T08:47:30Z (GMT). No. of bitstreams: 1 Farhate_CamilaVianaVieira_M.pdf: 1389650 bytes, checksum: dfc7da8cbdf154612091a7f2192cb780 (MD5) Previous issue date: 2015 / Resumo: A influência de práticas agrícolas na emissão de gases do efeito estufa é assunto de grande interesse, especialmente quando se trata do CO2, o principal componente do efeito estufa adicional. O preparo do solo é uma das atividades agrícolas que mais promove a decomposição de matéria orgânica e emissões de CO2 para a atmosfera. O rompimento dos agregados de solo promovido pelo preparo convencional, expõe a matéria orgânica, conduzindo à oxidação rápida e fluxo de CO2 para a atmosfera. Logo, acredita-se que a adoção do sistema de plantio com preparo do solo reduzido conciliado a rotação de culturas na cana-de-açúcar possa contribuir para um balanço positivo do CO2. Portanto, a pesquisa baseia-se nas seguintes hipóteses: i) As operações de preparo do solo de forma convencional associadas à adoção da rotação de culturas com Crotalária juncea potencializam as emissões de CO2 do solo ii) A rotação de culturas na cana-de-açúcar, em solos de textura arenosa, proporciona maiores variações no fluxo de CO2 solo e nos atributos do solo em relação aos solos de textura argilosa. Dessa maneira, o objetivo deste estudo foi avaliar o efeito do preparo do solo e da rotação de culturas no fluxo de CO2 e suas correlações com os atributos de dois solos de classes texturais distintas, cultivados com cana-de-açúcar. O trabalho foi conduzido em condições de campo em duas usinas do estado de São Paulo. O delineamento experimental foi o de blocos ao acaso no esquema de parcelas subdivididas com quatro repetições. A parcela envolve área com e sem rotação e a subparcela duas condições de preparo de solo (cultivo mínimo e preparo convencional). Cada subparcela foi composta por 15 linhas de cana-de-açúcar, com espaçamento de 1,5 m e 34 m de comprimento. Foram realizadas avaliações periódicas nas áreas visando acompanhar modificações no fluxo de CO2 nos atributos químicos, físicos, carbono da biomassa microbiana. Houve maior emissão de CO2 na área de solo argiloso. A rotação de culturas aumentou o FCO2 apenas na área de solo arenoso devido os resíduos de culturas provenientes da rotação de culturas terem modificado os atributos físicos que favoreceram o FCO2. O FCO2 foi maior na área de solo argiloso em relação ao solo arenoso. Nas áreas de solo arenoso e argiloso o efeito do preparo foi pouco claro, tendo mais destaque a rotação de culturas sobre os atributos do solo / Abstract: The influence of agricultural practices on the issue of greenhouse gases is a matter of great interest, especially when it comes to CO2, the main component of the additional greenhouse effect. Soil preparation is one of the agricultural activities that will promote the decomposition of organic matter and CO2 emissions to the atmosphere. Disruption of aggregates of the soil by conventional tillage promoted, exposes the organic matter oxidation and leading to the rapid flow of CO2 into the atmosphere. Therefore, it is believed that the adoption of planting system with reduced soil preparation reconciled crop rotation in the culture of sugar cane can contribute to a positive balance of CO2. Therefore, the research is based on the following assumptions: i) the preparation of conventional soil operation associated with the adoption of crop rotation with Crotalaria juncea potentiate the CO2 emissions of the soil ii) Crop rotation in sugar cane, in sandy soils, provides greater variations in soil CO2 flux and soil properties in relation to clayey soils. Thus, the aim of this study was to evaluate the effect of tillage and crop rotation on a CO2 stream and their correlation with the attributes of two different textural classes of soils cultivated with sugar cane. The work was conducted under field conditions in two plants in the state of São Paulo. The experimental design was a randomized block in split plot with four replications. The plot involves an area with and without rotation and the subplots two soil preparation conditions (minimum tillage and conventional tillage). Each subplot consisted of 15 lines of sugar cane, with spacing of 1.5 m and 34 m long. Periodic evaluations were performed in order to monitor changes in the areas of CO2 flow in the chemical, physical, microbial biomass carbon. There was a higher CO2 emissions of the clay soil area. Crop rotation increased FCO2 only in sandy soil area because the crop residues from crop rotation have modified the physical attributes that favored FCO2. The FCO2 was higher in clay soil area in relation to the sandy soil. In the areas of sandy soil and clay the effect of the preparation was unclear, with more emphasis in crop rotation on the soil / Mestrado / Agua e Solo / Mestra em Engenharia Agrícola