Orientador: Julio César Rocha / Resumo: Substâncias húmicas aquáticas (SHA) foram obtidas por processo de adsorção em resinas macroporosas não-iônicas, XAD 7 e XAD 2, dispostas em série. Após eluição com solução de NaOH, o extrato alcalino de SHA foi acidificado a pH 1,0 para separação em ácidos húmico (AH) que precipita, e ácido fúlvico (AF) o qual permanece em solução. Para caracterização físicoquímica do material húmico (AH e AF), foram feitas análise elementar, determinação do teor de substâncias húmicas e acidez total. Os resultados obtidos por UV-VIS e FTIR indicaram que AH apresenta maior número de grupos aromáticos em relação a AF, que em geral possui mais cadeias alifáticas. A aplicação da técnica imunoquímica, enzyme-linked immunosorbent assay (ELISA), para a determinação do herbicida atrazina em águas foi avaliada em amostra de água contendo alto teor de matéria orgânica (~35 mg L-1) e baixo valor de pH (3,8). O efeito matriz devido a presença de SHA pode ser notado pela perda de sensibilidade da técnica, ou seja, os valores de IC50 variaram de 60 ng L-1, na ausência de SHA, para 112 ng L-1 em concentrações acima de 10,0 mg L-1 de material húmico e para 137 ng L-1 em pH < 5,0. Além disto, pode-se inferir que a luz solar aumentou a velocidade de degradação da atrazina na presença de SHA formando produtos, com partes de suas estruturas, semelhantes ao produto original levando a resultados falso-positivos. A quantidade de material húmico presente na amostra de água foi a principal fonte de erro na análise de atrazina, levando à interações não-específicas entre as SHA e os reagentes enzimáticos. O procedimento ELISA, aplicado neste estudo, pode ser utilizado para determinação de atrazina desde que se faça diluição da amostra até cerca de 2,5 mg L-1 de húmicos e em pH alcalino (7,0 - 9,0). / Abstract: Aquatic humic substances (AHS) were isolated from water samples using Amberlite XAD 7 and XAD 2. After elution with NaOH solution, the XAD concentrated AHS was fractioned at pH 1.0 resulting in fulvic acid (FA - supernatant) and humic acid (HA - slurry). All humic materials were characterized with respect to elemental analysis, amount of AHS and total acidity. UV and FTIR spectra showed HA aromatic character greater than FA. Enzyme-linked immunosorbent assay (ELISA) was evaluated by analyzing atrazine in rich-humic matter water sample (~35 mg L-1) and acid water (pH 3.8). From all the conditions studied the low pH (pH < 5.0) and high humic substances concentrations (>10 mg L-1) showed the greatest influence. The IC50 values to control sample (no humic) decreased from 60 ng L-1 to 112 ng L-1 to humic solution at >10 mg L-1 and to 137 ng L-1 at pH < 5.0. The presence of AHS alters the photochemical behaviour of atrazine by accelerating its degradation forming metabolites which can be recognized by the antibodies. The assay performance showed a strong dependence on the pH values and amount of humic matter. However, analysis could be carried out directly in samples containing HA or FA that had been adjusted the pH in the range between 7.0 and 9.0, and humic concentration at 2.5 mg L-1. / Doutor

The partition of radionuclides between solid and solution phase has been studied in humic/quartz sand ternary systems. Data have been recorded under ambient (air) and inert (O2 and CO2 free) atmospheres. For Eu (III) and Th (IV), the systems show simple ternary behaviour, with sorption decreasing (and mobility increasing) in the presence of humic, whilst for U (VI), the behaviour is more complex, with the humic enhancing sorption and reducing mobility. There is also evidence that the sorbed humic has an enhanced affinity for the uranyl, which is probably due to fractionation of the humic. Further, the behaviour of plutonium has also been studied in these systems. Pu (IV) showed the simple ternary characteristics, which had been observed for Eu (III) and Th (IV). Pu (V) and Pu (VI) systems exhibited more complex behaviour, with low concentrations of humic actually enhancing sorption, probably due to ternary complex formation. A simple mathematical model has been developed to predict the behaviour of both metal ion and humic acid. The model performs well in predicting the partition of the humic and that of the metal ions in the systems that show simpler ternary behaviour.

Orientador: André Henrique Rosa / Resumo: When introduced in environment, manufactured nanoparticles (NPs) can interact with biotic and abiotic molecules yielding a transformed NP usually coated with these molecules (natural coating). These different forms of the NPs should be considered as new materials because them distinct properties from the released NPs forms. In fact, these in situ transformations of the NPs have relevant impacts on their toxicological effects, having new or additional risks still not studied. This project aims to determine, understand and predict the impact of natural molecules in the transformations and bio-effects of Ag NPs, widely used as antibacterial agents. Despite the growing interest and use of these NPs, the gathered knowledge on their environmental consequences is still scarce, since the large majority of the studies do not consider the effect of the presence of natural coatings around the particles. In fact, most of the studies do not even determine the effects of the presence of manufactured coatings. Generally, NPs manufacturers add ionic or polymeric coatings to improve their mobility and stabilization in terms of size. Although the possible effects of these manufactured coatings in the NPs behavior there is not systematically studied about their impact. This project aims to overcome the current uncertainty about the environmental safety of manufactured coated NPs, and explore the impact of natural molecules on their environmental risk. The project objectives are: i) characterize... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Orientador: André Henrique Rosa / Banca: Clóvis Augusto Ribeiro / Banca: Leandro Cardoso de Morais / Banca: Eny Maria Vieira / Banca: Ézio Sargentini Junior / Resumo: Neste trabalho caracterizou-se a distribuição e disponibilidade de cobre, chumbo e mercúrio totais em águas superficiais, substâncias húmicas e frações granulométricas de sedimentos coletados em mananciais dos três diferentes tipos de águas da bacia amazônica, ou seja, rios de água branca (barrenta), rios de água preta e rios de água clara. As amostras foram coletadas durante período de cheia e seca entre 2014 e 2015, nos reservatórios da Usina Hidredrétrica de Jirau (Rio Madeira - RO - água branca), da Usina Hidrelétrica de Cana Brava (Rio Tocantins - GO) e no baixo Rio Negro - AM. As concentrações das espécies analisadas estão de acordo com o disposto na Resolução CONAMA no 454/2012, a qual estabelece as diretrizes gerais e os procedimentos mínimos para a avaliação do material a ser dragado em águas, preconizando para Cu 35,7 e 197; para Pb 35 e 91,3; e para Hg 0,17 e 0,486 mg kg-1 em referência aos níveis 1 e 2, respectivamente. Os maiores valores médios de concentração de cobre total foram no rio com tipo de água branca (rio Madeira) em seguida no rio com tipo de água clara (rio Tocantins) e rio com tipo de água preta (rio Negro). Podendo-se assim estabelecer a seguinte ordem decrescente de concentração média de Cu nos sedimentos: água branca> água clara> água preta. Para chumbo, os maiores valores médios de concentração foram no rio com tipo de água branca em seguida no rio com tipo de água clara e rio com tipo de água preta. Pode-se estabelecer a seguint... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work, the distribution and availability of copper, lead and mercury in surface waters, humic substances and granulometric fractions of sediments collected from the three different types of waters of the Amazon basin, ie white water rivers (muddy), Rivers of black water and rivers of clear water. The samples were collected during the flood and dry period between 2014 and 2015, in the reservoirs of the Jirau Hydroelectric Plant (Rio Madeira - RO - white water), the Cana Brava Hydroelectric Power Plant (Rio Tocantins - GO) and the lower Rio Negro - AM. The concentrations of the species analyzed are in accordance with CONAMA Resolution 454/2012, which establishes the general guidelines and minimum procedures for the evaluation of the material to be dredged in waters, recommending for Cu 35,7 and 197; For Pb 35 and 91.3; And for Hg 0.17 and 0.486 mg kg -1 in reference to levels 1 and 2, respectively. The highest values of total copper concentration were in the river with a white water type (Madeira river), followed by a river with a clear water type (Tocantins river) and a river with a black water type (Rio Negro). It is possible to establish the following order of decreasing average concentration of Cu in the sediments: white water> clear water> black water. For lead, the highest values of concentration were in the river with white water type then in the river with clear water type and river with type of black water. The following order of average Pb conc... (Complete abstract click electronic access below) / Doutor

Orientador: André Henrique Rosa / Coorientador: Hubert Mathias Peter Roeser / Banca: Kurt Friese / Banca: Paulo Sérgio Tonello / Banca: Viviane Moschini Carlos / Banca: Ricardo Perobelli Borba / Resumo: O As está distribuído em diversas formas químicas em sistemas aquáticos, o que determina o seu comportamento e destino no ambiente. Nesse contexto, as substâncias húmicas (SH) têm um importante papel por serem capazes de complexar esse metaloide e alterar sua mobilidade e biodisponibilidade. O Fe também tem grande importância por poder formar complexos ternários SH-Fe-As. Apesar da química do As já ter sido bem estudada, o seu comportamento em ambientes ricos em SH e Fe ainda não é totalmente compreendido. Os objetivos desse trabalho foram investigar a distribuição do As, Al e Fe em águas superficiais de uma região mineira no sudeste do Brasil (Quadrilátero Ferrífero, QF) e entender como características de SH extraídas de diferentes regiões (Brasil e Alemanha) afetam a complexação do As(V) na presença de Fe(III). Amostras de águas foram coletadas em 12 pontos do QF, filtradas (0,45 µm) e ultrafiltradas (1 kDa) para separar as frações particulada (>0,45 µm), coloidal (<0,45 µm e >1 kDa) e livre (<1 kDa) de As, Al e Fe. A técnica de difusão em filmes finos por gradientes de concentração (DGT) foi usada em 5 dos 12 pontos para estudar a fração lábil dos elementos estudados. Carbono orgânico total (COT) e dissolvido (COD) também foram medidos. SH foram extraídas de quatro pontos (um no Brasil nas estações seca e chuvosa e três na Alemanha) para testar a influência de diferentes tipos de SH e Fe(III) na complexação do As(V). As SH foram caracterizadas e foram feitos testes de comp... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: As is distributed in different chemical forms in aquatic systems. These different forms control its behaviour and fate in the environment. The humic substances (HS) have an important role in the As cycle since they can complex this metalloid and change its mobility and bioavailability. Fe is also important because it can form ternary complexes HS-Fe-As. Although the As chemistry is well studied, the behaviour of As in HS and Fe-rich environments is not totally known. This thesis aimed to investigate the distribution of As, Al and Fe in surface waters from a mining region in the southeast of Brazil (Quadrilátero Ferrífero, QF) and understand how characteristics of HS extracted from different regions (Brazil and Germany) affect the complexation of As(V) in the presence of Fe(III). Water samples were taken in 12 points in QF, filtered (0.45 µm) and ultrafiltered (1 kDa) to separate the fractions particulate (>0.45 µm), colloidal (<0.45 µm and >1 kDa) and free (<1 kDa) of As, Al and Fe. The technique of diffusive gradients in thin films (DGT) was used in 5 of the 12 points to study the labile fraction of the elements studied. Total organic carbon (TOC) and dissolved organic carbon (DOC) were also measured. HS were extracted from four points (one in Brazil in dry and rainy seasons and three in Germany) to analyse the influence of HS from different origins and Fe(III) on the complexation of As(V). The HS were characterised and complexation experiments were performed using an ultrafiltration system with 1 kDa membrane. All data were analysed using the Kohonen neural network. The results showed that most of total Al and Fe in QF was in the particulate fraction and As was in the free fraction. Most of the dissolved Al and Fe was in the colloidal and inert fraction, while As was more labile and potentially more bioavailable ... (Complete abstract click electronic acess below) / Doutor

Humic substances (HS) are the humified portions of totally decomposed soil organic matter that are ubiquitous in nature. Although these substances have been studied for more than 200 years, neither their metabolic capabilities nor a specific chemical structure has yet to be determined. HS have been studied as a carbon source in many environments where they are degraded; however, previous studies have shown that some microorganisms are capable of utilizing humic substances as electron acceptors and electron donors in anaerobic respiration. Even though there have been humic-reducing and humic-oxidizing microorganisms isolated and studied in recent years, the mechanism of humics metabolism and its interaction in the natural environment are not well understood. However, it is known that the continuous change in the redox state of HS is important to the cycling of iron, stability of nitrogen and carbon, and the mobility and bioavailability of inorganic and organic environmental pollutants. In this study, microbial communities were examined to evaluate the community dynamics of nitrate-dependent HS-oxidizing populations and to provide a snapshot of the phylogenetic diversity of these microorganisms. Column studies were performed using nitrate as the sole electron acceptor and the following as the electron donors in different columns: reduced humic acids, oxidized humic acids, and acetate as the control. Liquid buffered media was added to a separate column to serve as an additional control. Polymerase chain reactions of the 16S rRNA genes using DNA from the column studies were performed and analyzed by constructing 16S rDNA clone libraries and by performing denaturing gradient gel electrophoresis (DGGE). Clones from the library have been sequenced and analyzed to paint a phylogenetic picture of the microbial community under the various conditions. Results indicate that the majority of the clones were assigned to four well-characterized divisions, the Acidobacteria, the Bacteroidetes, the Firmicutes, and the Proteobacteria. Additional findings suggest that members related to Bacteroidetes are involved in some sort of HS cycling in the environment or may be excellent electron scavengers enabling them to outcompete other microorganisms and that members of Proteobacteria may be the dominant HS-oxidizing microorganisms in natural environments. An additional aspect of this project hypothesizes that specific genes are differentially expressed when HS-oxidizing bacteria are growing on reduced HS as compared to acetate or in the presence of oxidized HS. To test this hypothesis, the global gene expression profile of Acidovorax ebreus strain TPSY was assessed using microarray analysis. This method led to the identification of several genes potentially involved in nitrate-dependent HS oxidization and a proposed model for this respiratory process in strain TPSY. The final section in this project was designed to assess in-service teachers' perceived levels of familiarity with and interest in learning more about selected microbiology concepts and their actual understanding of the selected microbiology concepts. Sixty-two in-service elementary, middle, and high school teachers from several school districts across southern Illinois completed a three-part instrument that included additional open-ended questions to gain more information about the teachers' conceptual understanding. The results of this study suggest that teachers who hold a teaching certification specific for teaching life science have taken more life science courses and scored significantly higher on the familiarity and conceptual knowledge sections of this study. The current research explores what is currently known about humic substances, specifically humics as an electron donor, analyzes the community structure in a humics oxidizing environment, identifies genes that are induced under nitrate-reducing, HS-oxidizing conditions, and evaluates the importance of microbiology to biological scientific literacy in today's society.

Humic substances (HS) are described as a complex mixture of organic molecules formed by incomplete decomposition of plant, animal and microbial matter. They are found in soil, water and air and have many environmental roles, e.g. water retention and metal ion binding in soil. Despite their importance, the molecular composition of HS is poorly understood. This is mostly because of an inability to separate individual molecules from these complex mixtures and then characterise them by standard analytical methods such as NMR and MS. In order improve the understanding of these important mixtures I have studied them using a high-resolution analytical method, Fourier transform ion-cyclotron resonance mass spectrometry (FTICR MS). Initial efforts focussed on testing the, fast, automated data analysis of the large data sets produced. Two pieces of software were compared and the reliability of the formulae assigned by these was critically evaluated. This confident formula assignment was then applied to study the consequences of different ionisation and instrumental parameters on the mass spectra obtained. The use of laser desorption/ionisation (LDI) without the need to employ a matrix required in matrix assisted laser desorption/ionisation (MALDI) was explored. A comparison of LDI and electrospray ionisation (ESI) FTICR MS of natural organic matter samples showed that these methods ionise complementary sets of compounds. The LDI ionised compounds were characterised as aromatics or condensed aromatics and compounds belonging to lower oxygen classes (maximum number at O8), while ESI ionised higher oxygen classes (maximum number at O16) with a vast majority of compounds classified as aliphatic based on their modified aromaticity index. MALDI and LDI spectra produced very similar data with over 90% matching formulas implying that fragmentation is not caused by LDI, as taught previously. My work showed that to maximize the coverage by FTICR MS of the molecular space occupied by these complex mixtures, multiple ionization methods must be used. As a particularly convenient and readily deployable ionization technique, LDI should be included in standard analytical protocols for FTICR MS analysis of NOM. I have explored different parameters and experimental settings to obtain a fuller coverage of the molecular space of NOM, this showed that different experimental conditions enhance peak intensities in different m/z regions of the FTICR MS spectra and that information can be obtained outside of the narrow 200-700 m/z window. To gain chemical and structural information about humic substances beyond what is currently known, experiments aimed to label HS using different isotopes and at specific sites were developed and tested. Two methylation reactions were of particular interest. A methylation that selectively targeted carboxylic acid groups and incorporated deuterium in the form of CD3 groups. An international standard, Suwannee River fulvic acid, was methylated and analysed by high-resolution mass spectrometry in order to gain information on the number and distribution carboxylic acid groups. This proved challenging due to the reactivity of the unknown molecules being difficult to determine in advance. Additionally, the peak separation being reduced to as low as 1.5 mDa pushed the instrument resolution and assignment confidence to their limits. The second methylation method explored used 13CH3I, a nonselective agent reacting with any labile proton, particularly attaching 13CH3 groups to carboxylic, phenolic and alcoholic OH groups. I prepared a methylated sample of fulvic acid from a Red Moss raised bog (Balerno, near Edinburgh) ready for analyses by high field NMR. This investigation yielded structures of a number of phenolic compounds for the first time by NMR.

Made available in DSpace on 2014-06-11T19:29:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-20Bitstream added on 2014-06-13T19:38:01Z : No. of bitstreams: 1 pantano_g_me_sjrp.pdf: 2292416 bytes, checksum: 9d6b67d9f91bd16297d9375759c79205 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve como objetivo estudar a interações das Substâncias Húmicas (SH) com os metais cobre(II), cromo(III) e cromo(VI) por meio de dois métodos, o da supressão da fluorescência molecular e o sistema de ultrafiltração com fluxo tangencial (SUFT). As SH foram caracterizadas por técnicas espectroscópicas na região do infravermelho e do ultravioleta-visível e por fluorescência molecular. Foram realizadas duas coletas de sedimentos, uma no período de chuva e outra no de seca, sendo coletados em três rios da Bacia Hidrográfica do Turvo/Grande, Rio Preto, Rio Turvo e Rio Grande. O sedimento foi coletado com o auxilio de uma draga manual do tipo Van Veen. As SH foram extraídas de acordo com metodologia oficial sugerida pela Sociedade Internacional de Substâncias Húmicas (SISH). A constante de estabilidade condicional (Kc) foi determinada por meio da supressão da fluorescência e variou de 5,6x10-3 – 1,23 em período chuvoso para o íons cobre, e de 5,5x10-3 – 8,7x10-2 para o período de seca. Quando a Kc foi determinada para o complexo SH-Cr(III) valores de 1,9x10-1-5,2x10-1 e 2,1x10-1-3,5x10-1, foram determinados para o período de chuva e de seca, respectivamente. Por fim a Kc foi determinada para a interação das SH com Cr(VI), de forma geral os valores de Kc foram maiores para o período de chuva. A capacidade complexante (CC) determinada por meio do SUFT para a interação das SH com cobre(II) teve valores que variaram de 4,0x10-1 – 6,3x10-1 mmol Cu g-1 SH e de 1,4x10-1 – 5,3x10-1 mmol Cu g-1 SH para período de chuva e seca, respectivamente. Para o Cr(III) a CC variou de 2,1x10-1 – 9,7x10-1 e de 2,6x10-1 – 8,4x10-1 mmol Cr g-1 SH para o período de chuva e seca, respectivamente. Quando a interação das SH com o Cr(VI) foi estudada por meio do SUFT só foi possível calcular a CC para os pontos... / This work aimed to study the interactions of humic substances (HS) with copper(II), chromium(III) and chromium(VI), using by two methods, the suppression of the molecular fluorescence and tangential flow ultrafiltration sytem (TFUS). The HS were characterized by spectroscopic thecniques in the infrared and ultraviolet/visible region and molecular fluorescence. There were two sediment samples, one during the wet season and another the dry, being these sediments collected from the three Rivers of the Turvo/Grande drainage basin, Preto river, Turvo river and Grande river. The collection of sediment was carried out with the aid of a manual Van Veen type dredge. The HS were extracted according to the official methodology suggested by the International Humic Substances Society (IHSS). The conditional stability constant (Kc) was determined by suppressing fluorescence and ranged from 5,6x10-3 – 1,23 in the wet season for the copper ions, and of the 5,5x10-3 – 8,7x10-2 to the dry season. When Kc was determined for the complex HS-Cr(III) values of 1,9x10-1-5,2x10-1 e 2,1x10-1-3,5x10-1, were determined for the wet and dry seasons, respectively. Finally, the Kc was determined for the interactions oh HS with the Cr(VI) in geral the Kc values were higher for the wet season. Complexant capacity (CC) was determined by means of TFUS for the interactions of the HS with Copper(II) the values ranged from 4,0x10-1 – 6,3x10-1 mmol Cu g-1 HS and of 1,4x10-1 – 5,3x10-1 mmol Cu g-1 HS for a wet and dry season, respectively. For the Cr(III) CC ranged from 2,1x10-1 – 9,7x10-1 and from 2,6x10-1 – 8,4x10-1 mmol Cr g-1 HS for the wet and dry period, respectively. When the interactions oh HS with Cr(VI) was studied by means of TFUS was only possible to calculate the CC for the points NRP and CAPRP, as for others... (Complete abstract click electronic access below)

Types of intrinsic fluorophores were characterized in several soil humic and fulvic acid samples and the photochemical stability of the fluoropheres under UV (300 {--} 400 nm) irradiation was tested.

The new forms of superabsorbent polymers (SAP) on the base of acrylic acid were developed and studied in this thesis. The SAP are focused on agricultural and environmental applications. While they are applied to the soil, SAP can prevent water losing and they become a reservoir of humidity in case of dry season, moreover in combination with fertiliser they play role of controlled release medium. Eight various samples of SAP were experimentally prepared by networking of partially neutralized acrylic acid. Potassium peroxydisulfate was used as the initiator and N,N–methylenebisacrylamide as the crossing agent. Some of samples contained addition of second monomer of acrylamide. All of them were enriched by fertilisers – natural lignohumate or synthetic NPK or combination of both. The swelling characteristics of prepared samples were investigated in conditions of various ionic strength. The influence of xerogels’ particles size on swelling properties was also observed. The viscoelastic characteristics of hydrogel form of all SAP were determined by using of rotation rheometer. The changing of viscoelastic properties were studied in dependence on time, on freezing and on repeating swelling cycles. On top of that the controlled releasing ability of SAP was tested due to three modelling experiments. The biological activity of all polymer products was tested at the end of the thesis. All samples of SAP were incorporated into the artificial soil and the ability of the water retention in the soil was observed. The growing experiments were running by using of corn plants. The size and the mass of each plant were measured and branching of the root was objectively evaluated by programme Harmonic and Fractal Image Analyzer.