The emission of trace metals (TMs) into boreal forest regions of the northern hemisphere is an important environmental issue due to their potential detrimental impacts on these sensitive ecosystems. One of the foremost factors controlling metal cycling is the chemistry of the overlying organic forest floor of the forest soil. In this thesis we examine the chemistry of forest floor horizons of podzolic soils. Our goal is to improve our ability to predict the partitioning of metals between the soil solid and solution phases. / We developed a standard protocol to produce solutions that resemble lysimeter solutions from podzolic soils using air-dried samples. We hypothesized that the stabilization point of the electrical conductivity (EC) of the soil solution is indicative of the point in which soluble salts and organic material precipitated during sampling and storage are removed from the soil particle surfaces. Solutions produced by leaching the soils, once the EC of wash solutions had stabilized, were comparable to lysimeter solutions from the area where samples were collected with respect to the concentrations of divalent cations, pH, EC and dissolved organic carbon (DOC). The applicability of this procedure to trace metal partitioning in forest floors was explored. Laboratory extractions produced partition coefficients (log Kd) similar to observed lysimeter solutions ranging from 3.4 to 3.9 for Cd, 3.4 to 3.9 for Cu, 3.4 to 4.1 for Ni, 4.1 to 5.2 for Pb and 3.2 to 3.5 for Zn. According to a semi-mechanistic regression model based on observed lysimeter concentrations, the metal concentrations in solution were appropriate relative to known factors that influence metal partitioning in soils: pH, the concentrations of total metals and DOC. / While chemical characteristics of soils have been consistently observed to play important roles in the partitioning and toxicity of metals we wished to place the importance of the chemical characteristics of soil on mobility and toxicity in context. We interpreted field data that had been collected from transects established with distance from two point source emitters in Rouyn PQ, and Sudbury ON. Canada find developed equations that predict dissolved metal concentrations from total metal concentrations, soil pH, soil organic matter (SOM), and DOC contents. We integrated these equations into a simple box model that calculates changes in the concentration of metals in the organic and upper mineral horizons and includes a loop for vegetative return of metals to the forest floor.

Recent advances in otolith microchemistry have established that trace element composition can be used to chemically reconstruct fish life history and serve as a stock identification tool. In modern fisheries practices, these two applications are especially pertinent to wild salmon populations, which are difficult to track over large spatial scales and nearly impossible to identify in mixed populations. This project has applied a novel method using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to anadromous sockeye salmon (Oncorhynchus nerka) otoliths from four separate watersheds in Sitka, Alaska. Spatial distributions of Li, Mg, Mn, Zn, Sr, and Ba were determined via continuous lateral ablation scans across the diameter of transversely sectioned sagittal otoliths. Time-series data generated from line scan analysis were used to chemically reconstruct sockeye life history, and examine elemental signatures in the core, freshwater, and marine growth regions of otoliths for stock identification purposes. Chemical profiles of life history showed that Sr, Ba, and to a lesser degree Mg, reflected ambient chemistry, and were effective for tracking sockeye migration from fresh to marine water. Manganese was also effective for determining migration to fresh and marine water; however, it is believed that diet more than ambient chemistry is the factor controlling uptake. Elements such as Zn and Li provided information related to fish physiology, such as growth and changes in osmoregulation during transitions from low to high salinity environments. Results also showed that several elements were either enriched or depleted in the core of sockeye otoliths. Maternal investments and spatial differences in crystal structure are believed to significantly affect element uptake in otoliths during incubation and early development. Elemental signatures in the otolith core may therefore be inaccurate as an indicator of stock origin. This problem was investigated by isolating core, freshwater, and marine signatures and evaluating individually their ability to correctly classify sockeye otoliths to their natal watersheds using step-wise discriminant function analysis. This demonstrated that freshwater signatures provided the greatest accuracy (91%) for stock ID. Core signatures, which have been used in past stock ID studies, showed poor classification results (68%) for sockeye salmon otoliths. Trace element signatures from the marine growth regions of sockeye otoliths displayed the poorest classification accuracy (52.5%) of the three growth regions. Thus, freshwater signatures are the most effective tool for identifying the origin of wild salmon, even when they far removed from their natal watersheds.

One of the first concerns for forensic anthropologists in dealing with skeletal remains in the Australian context is the determination of whether the remains are of anthropological, historical or archaeological interest. If fewer than 75 years have elapsed since death, remains are classified as anthropological and of forensic interest. However, an accurate and reliable method for estimating time since death (TSD) from human skeletal remains has thus far eluded forensic anthropologists. This study investigates the application in an Australian context of a novel approach proposed by Swift (2001) to dating skeletal remains from their contained levels of radioisotopes 210Po, 238U and 226Ra and trace elements. Radionuclide activity concentrations were determined using alpha and gamma spectrometry. Trace element concentrations were measured on three separate occasions using inductively coupled plasma mass spectrometry (ICP-MS). Discriminant analysis of the combination of activity concentration values for 210Po, 238U and 226Ra indicated the possibility of separation of bones derived from individuals who had died in the three eras of interest. Additionally, variations in the concentration levels of specific trace elements and certain inter-element relationships between elements also showed significant correlations with TSD. The study could not be exhaustive as access to human skeletal material was limited and additionally, the archaeological material had a different origin and post-death history to material from the more recent past. However, trend lines for inter-relationships between specific metals and for radionuclides indicated that all material fitted the same generally projected trends and as such, inferences with respect to variations of trace elements and radionuclides could be made with confidence. Bone radionuclide activity and calcium concentrations were all significantly higher in bones from the archaeological era than those from more recent eras, while trace lead concentrations contained in samples from the more recent historical era were significantly higher than those from other eras. Barium, lanthanum, rubidium, strontium, cerium and neodymium concentrations were all significantly correlated with one another and with radionuclide activity concentrations. Differences were found between the patterns of radionuclide activity and trace element concentrations between the skull and femur. The results of this study lend support to suggestions that multivariate analysis of trace element concentrations and radionuclide activity levels could aid in the estimation of time since death from skeletal remains in Australia. Although this study made use of only a limited amount of material, results clearly indicated the need to take into account variations arising from lifetime activities, diagenesis and bone type in applying the techniques to estimations of time since death. It highlights the need for a large-scale study using bone of known ages that systematically examines these influences on the estimation of time since death.

Submitted by (edna.saturno@ufrpe.br) on 2016-07-19T15:03:07Z No. of bitstreams: 1 Daniel Nunes de Araujo Goncalves.pdf: 823982 bytes, checksum: 6687205bfd4864be47ed20ae298a8a5b (MD5) / Made available in DSpace on 2016-07-19T15:03:07Z (GMT). No. of bitstreams: 1 Daniel Nunes de Araujo Goncalves.pdf: 823982 bytes, checksum: 6687205bfd4864be47ed20ae298a8a5b (MD5) Previous issue date: 2013-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study aimed to assess liver concentrations of cobalt (Co) in goats and sheep in the backlands of Pernambuco. For this we considered the seasonality factors, species and sex. The liver samples were obtained from animals slaughtered in the towns of Granite, and Araripina Ouricuri. Randomly selected a total of 206 animals, 77 goats (35 males and 42 females) and 129 sheep (86 males and 43 females). He was chosen the final third of each seasonal period for the completion of the collections. The samples went through the process of kiln drying, weighing, microwave wet digestion model MarsXpress - EMC Technology Inside and subsequent analysis by atomic absorption spectrometry coupled with mass (ICO-OES). It was observed that liver concentrations of Co in goats and sheep reared and slaughtered in the backlands of Pernambuco is at appropriate levels. Reference data for sheep and goats showed, respectively, means and standard deviations of the liver concentrations Co: sheep (0.59 ± 0.07 mg / kg) and goats (0.63 ± 0.08 mg / kg) ; males (0.56 ± 0.07 mg / kg) and females (0.66 ± 0.07 mg / kg), dry season (0.61 ± 0.08 mg / kg) and rainy season (0.61 ± 0.07 mg / kg). It was observed that the mean concentrations of Co for sheep and goats were not affected by seasonal period (P <0.9861), species (P <0.7326) and sex (P> .3805). The data are used to guide diagnostic studies on these species bred in Cobalt Hinterland Pernambucano, however we stress that more research is needed on the subject, since the region is known for presenting animals with various deficiencies of macro and trace minerals. / Objetivou-se aferir a concentração hepática de cobalto (Co) em caprinos e ovinos no Sertão do Estado de Pernambuco. Para isso foram considerados os fatores sazonalidade, espécie e sexo. As amostras de fígado foram obtidas de animais em abatedouro dos municípios de Granito, Araripina e Ouricuri. Foram escolhidos aleatoriamente um total de 206 animais, sendo 77 caprinos (35 machos e 42 fêmeas) e 129 ovinos (86 machos e 43 fêmeas). Foi escolhido o terço final de cada período sazonal para a realização das coletas. As amostras passaram por processo de secagem em estufa, pesagem, digestão úmida por microondas modelo MarsXpress – CEM Tecnology Inside e posterior análise por espectrometria de absorção atômica acopladas a massa (ICO- OES). Observou-se que a concentração hepática de Cobalto em caprinos e ovinos criados e abatidos no Sertão do Estado de Pernambuco encontra-se em níveis adequados. Dados referenciais dos ovinos e caprinos demonstraram, respectivamente, as respectivas médias e desvios-padrão da concentração hepática de Co: ovinos (0,59±0,07 mg/kg) e caprinos (0,63±0,08 mg/kg); machos (0,56±0,07 mg/kg) e fêmeas (0,66±0,07 mg/kg); período seco (0,61±0,08 mg/kg) e período chuvoso (0,61±0,07 mg/kg). Observou-se que a média das concentrações de Cobalto para ovinos e caprinos não sofreram influência do período sazonal (P>0,9861), da espécie (P>0,7326) e do sexo (P>0,3805). Os dados servem de referência para diagnóstico de estudos sobre Cobalto nestas espécies criadas no Sertão Pernambucano, todavia ressalta-se que mais pesquisas sobre o assunto são necessárias, visto que a região é conhecida por apresentar animais com diversas deficiências de macro e microminerais.

Orientadores: Telma Teixeira Franco, Gustavo Paim Valença / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-15T16:00:27Z (GMT). No. of bitstreams: 1 Ayres_BiancaMairaTeixeira_M.pdf: 702836 bytes, checksum: 9d7d2a539cf470dfe7892bf64c17518d (MD5) Previous issue date: 2010 / Resumo: O presente trabalho estudou as melhores condições para a produção de monoacrilato de frutose a partir da esterificação de ácido acrílico com D-frutose catalisada pela lípase comercial de Cândida antárctica (Novozyme 435). O interesse na produção deste éster se dá devido à promissora propriedade absorvente de água do polímero a ser produzido, com diferentes aplicações possíveis. Esterificações enzimáticas são reações de equilíbrio cujo subproduto é a água. A presença desta tem de ser controlada para possibilitar atividade enzimática e evitar a hidrólise dos ésteres. A adição de peneira molecular 3 Á ao sistema foi investigada para remoção da água produzida e favorecimento do deslocamento do equilíbrio para síntese dos ésteres. A produção exclusiva de monoéster foi observada quando a razão molar frutose:ácido acrílico de 1:3, 55 °C, agitação de 200 rpm e 20 mg mL-1 de lípase foram empregadas. Quando a razão molar foi aumentada para 1:5 a conversão de frutose aumentou, mas o equilíbrio foi deslocado para a produção de di- e triéster de frutose. A adição de 3 g de peneira molecular em 25 mL de sistema reacional resultou na produção de 49.5 mM de monoacrilato de frutose com 84 % de conversão da frutose inicial e 41 % da conversão de ácido acrílico após 24 h de reação. Devido à inexistência de padrões de acrilatos de frutose no mercado, um método para quantificação destes por fatores de resposta de CLAE foi desenvolvido baseado nos dados cinéticos da reação / Abstract: The optimal conditions for the enzymatic production of fructose acrylates were studied. Fructose to acrylic acid molar ratio, the amount of immobilized lipase Candida antarctica and the influence of molecular sieve in the reaction media were studied. The results of these variables in converting sugar were monitored. Enzymatic esterifications are equilibrium reactions whose subproduct is water. The presence of this must be controlled to allow enzymatic activity of the lipase and to avoid hydrolysis of esters. The addition of molecular sieve 3 A to the system was investigated to remove of produced water and to shift the equilibrium to the synthesis of ester. The exclusive production of monoester was observed when the molar ratio of fructose: acrylic acid of 1:3, 55 °C, 200 rpm and 20 mg ml-1 of immobilized lipase was employed. When the molar ratio is increased the conversion of fructose increases, but the equilibrium was shifted to the production of di- and triester. The addition of 3 g of molecular sieve resulted in the production of 49.5 mM of fructose monoacrylates, 84 % conversion of the initial fructose and 41 % conversion of acrylic acid after 24 hours of reaction. Since sugar acrylates are not available, it were obtained the concentrations of esters from the determination of response factors of each ester by HPLC-RI based on linear regression / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

A barragem Mãe d\'Água foi construída em 1962, com o intuito de atender à demanda da Universidade Federal do Rio Grande do Sul UFRGS, mais precisamente o Instituto de Pesquisas Hidráulicas &#8211; IPH, porém, devido à falta de planejamento urbano, durante os últimos anos, vem acarretando uma diversificada série de passivos ambientais, como contaminantes orgânicos e/ou inorgânicos. Neste seguimento, o presente trabalho buscou avaliar as concentrações totais dos metais e a composição isotópica por chumbo 210 nas diferentes frações de sedimentos produzidos na bacia hidrográfica que compõe a barragem Mãe d\'Água e, assim, caracterizar a distribuição da concentração dos metais ao longo da coluna sedimentar e inferir quanto ao processo de urbanização da bacia hidrográfica caracterizando a evolução. Com referência nestas concentrações dos metais encontradas nos sedimentos, construir uma perspectiva do processo evolutivo da degradação ambiental na qual a bacia vem sendo submetida através de estudos de geocronologia (210Pb). As coletas das amostras foram realizadas em junho de 2014, sendo amostrados testemunhos sedimentares distribuídos no lago da referida barragem e o levantamento batimétrico. Para a extração dos testemunhos foi utilizado um amostrador de núcleo Piston core. Com os resultados obtidos, foramrepresentadas as concentrações dos metais Zn e Ni os quais apresentaram tendências de enriquecimento, a geocronologia datou as camadas assoreadas sendo o maior intervalo de 42 anos de deposição sedimentar, o volume do assoreamento ocupando aproximadamente 44% do volume útil do reservatório e a taxa de urbanização com tendências de crescimento e para o ano de 2014 com 88,42% da bacia urbanizada, configurando portanto uma distribuição espacial e estabelecendo correlações entre os estudos da sedimentação ao longo das últimas cinco décadas. As concentrações dos metais presentes nas amostras foram, também, comparadas com os valores de background do local para melhor visualizar o processo de enriquecimento dos sedimentos por ações antropogênicas. Foi possível concluir que com a ampliação das áreas urbanizadas, acarretou no aumentou das concentrações dos metais e no volume de sedimentos depositados no reservatório, onde a urbanização sem planejamento desta bacia é o principal fator poluidor. / The Municipality of Viamão is located in the metropolitan area of Porto Alegre, in the state of Rio Grande Sul. The Mãe d\'Água dam was built in 1962, with the purpose of meeting the demand of the Federal University of Rio Grande do Sul - UFRGS. Precisely because of the lack of urban planning during the last forty years, has led to a diversified series of environmental liabilities, such as organic and/or inorganic contaminants. The present work aimed to evaluate the total concentrations of metals and the isotopic composition per lead 210 in the different fractions of sediments produced in the watershed that make up the Mãe d\'Água dam and thus characterize the distribution of the concentration of metals along of the sedimentary column and infer about the process of urbanization of the watershed characterizing evolution. With reference to these concentrations of the metals found in the sediments, to construct a perspective of the evolutionary process of the environmental degradation in which the basin is being submitted through studies of geochronology (210Pb). Samples were collected in June 2014, and sediment deposited in the lake of the dam and bathymetric survey were sampled. A \"Piston core\" core sampler was used to extract the samples. With the results obtained, the concentrations of the metals Zn and Ni were presented, which presented enrichment tendencies, geochronology dating to the silted layers, silting volume occupying approximately 44% of the useful volume of the reservoir and the rate of urbanization with growth tendencies and for the year 2014 with 88% of the urbanized basin, thus constituting a spatial distribution and establishing correlations between sedimentation studies over the last four decades. The concentrations of the metals present in the samples were also compared with the background values of the site to better visualize the process of sediment enrichment by anthropogenic actions, where it was possible to verify that the expansion of the urbanized area increased the concentrations of the analyzed metals (Zn and Ni). It was possible to conclude that with the expansion of the urbanized areas, the increase of the concentrations of the metals and the volume of sediments deposited in the reservoir, where unplanned urbanization of this basin is the main polluting factor, resulted.

Carbonatites are unique and enigmatic magmatic rocks of unclear origin, with very specific mineralogy and geochemical properties. They are predominantly composed of magmatic calcite or other carbonate minerals (Le Bas 1987) and have low content of SiO2 (Le Maitre 2002). Origin of these peculiar magmas is still not clear but they appear to represent an important "window" into processes in Earth's mantle. They are considered either as residual melts from a fractionated carbonated nephelinite or melilitite (Gittins 1989; Gittins and Jago 1998), as immiscible fractions of CO2-saturated silicate melts (Freestone and Hamilton 1980; Amundsen 1987; Kjarsgaard and Hamilton 1988, 1989; Brooker and Hamilton 1990; Kjarsgaard and Peterson 1991; Church and Jones 1995; Lee and Wyllie 1997; Dawson 1998; Halama et al. 2005; Brooker and Kjarsgaard 2011), or as primary melts which are were generated from CO2-bearing peridotite through partial melting (Wallace and Green 1988; Sweeney 1994; Harmer and Gittins 1998; Harmer et al. 1998; Ying et al. 2004). Abundances of rare earth elements (REE) are often high in carbonatites because carbonatitic magmas can dissolve these elements much easily than silicate magmas (Nelson et al. 1988). Carbonatitic magma can also dissolve large quantities of Sr, Ba, P and mainly Zr and Nb,...

No description available.

Melting processes in the mantle have a key role in plate tectonics and in the most colossal phenomena in the Earth, like large igneous provinces, mantle plume upwellings, and the constant growth of the planet's tectonic plates. In this study we use the geochemical and petrological evidence preserved in ophiolites, large igneous provinces, and intraplate seamounts to understand causes, timing and implications of melting in these different tectonic environments. We studied melting at extensional environments, in mid-ocean ridges and back-arc basins, preserved in ophiolites. The Santa Elena Ophiolite in Costa Rica comprises a well-preserved fragment of the lithospheric mantle that formed along a paleo-spreading center. Petrological models of fractional crystallization suggest deep pressures of crystallization of >0.4 GPa for most of the samples, in good agreement with similar calculations from slow/ultra-slow spreading ridges and require a relatively hydrated (~0.5 wt% H2O) MORB-like source composition. Our findings suggest a complex interplay between oceanic basin and back-arc extension environments during the Santa Elena Ophiolite formation. Secondly, we analyzed large igneous provinces and their mechanisms of formation. As the surface expression of deep mantle processes, it is essential to understand the time frames and geodynamics that trigger these massive lava outpourings and their impact to life in the planet. We analyze the record and timing of preserved fragments of the Pacific Ocean Large Igneous Provinces to reconstruct the history of mantle plume upwellings and their relation with a deep-rooted source like the Pacific Large Low Shear Velocity Province during the Mid-Jurassic to Upper Cretaceous. Lastly, we explore the occurrence of low-volume seamounts unrelated to mantle plume upwellings and their geochemical modifications as they become recycled inside the mantle, to answer questions related to the nature and origin of upper mantle heterogeneities. We present evidence that an enriched mantle reservoir composed of recycled seamount materials can be formed in a shorter time period than ancient subducted oceanic crust, thought to be the forming agent of the HIMU mantle reservoir endmember. A "fast-forming" enriched reservoir could explain some of the enriched signatures commonly present in intraplate magmas not related with an active mantle plume upwelling. / Ph. D.

Conventional thermobarometry in metamorphic systems has been primarily limited to constraining peak temperature (or pressure) along a generalized P-T loop. This is largely attributed to the assumption that mineral assemblages and chemistries achieve a state closest to equilibrium with the maximum thermal (and therefore energetic) input at these peak conditions. However, this traditional approach is limited in providing much information about the evolution of a metamorphic terrane, which is modified by tectonic (kinematic) forces, fluid and component mobility, and heating duration. The ubiquity of quartz in the continental crust has driven much interest in using the phase for thermobarometric purposes. In this dissertation, I discss the application of elastic theory in reconstructing conditions of inclusion encapsulation through inclusion pressure estimation with Raman spectroscopy. In some instances, overpressuring of quartz inclusions in garnet give evidence for high-pressure formation conditions. When analyses are collected from garnet core to rim, pressure paths along garnet growth can be inferred (if temperature can be reasonably estimated). In high-T, low-P terranes, quartz may become dilated if the inclusion adheres to the host. If a quartz inclusion is sufficiently stretched, transformation to a low-density polymorph may occur. Trace element uptake, particularly Ti, have been characterized in quartz and understood to be the result of a temperature- (and to a lesser extent, pressure-) sensitive substitution for Si4+. However, the application of the Ti-in-quartz thermobarometer in quartz mylonites has led to mixed results due to the low-Ti resetting that occurs with dynamic recrystallization. We applied defect energy simulations and took a global assessment of deformed quartz trace element chemistries to infer that sweeping grain boundaries provide short pathways that allows localized re-equilibration with a Ti-undersaturated medium, resulting in Ti removal from the quartz lattice. In addition, thermodynamic pseudosection modeling has provided a method to assess Ti activity as a dynamic parameter – one that evolves as the phase stability changes through prograde and retrograde metamorphic reactions. With this understanding, better growth-composition models can be derived to infer complex pressure-temperature-time-deformation (P-T-t-D) histories of metamorphic rocks. These techniques and results are coupled with conventional thermobarometry techniques to provide a more comprehensive picture of the conditions experienced by a rock through the evolution, from burial to exhumation to the Earth's surface. The thermal evolution is used to provide conceptual thermal-kinematic models to explain tectonic evolution and heat advection in the continental lithosphere in ancient mountain belts. / Ph. D.