Note:

No description available.

No description available.

Submitted by RUTH HELENA GIANSANTE null (ruthhgster@gmail.com) on 2018-04-03T13:04:19Z No. of bitstreams: 1 RUTH_GIANSANTE_DISS_versão final (20DEZ2017) (5)6.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-03T18:23:48Z (GMT) No. of bitstreams: 1 giansante_rh_me_jabo.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) / Made available in DSpace on 2018-04-03T18:23:48Z (GMT). No. of bitstreams: 1 giansante_rh_me_jabo.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) Previous issue date: 2017-11-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Rizobactérias são excelentes candidatas à aplicação em processos de bioacumulação de elementos potencialmente tóxicos, pois desenvolveram mecanismos para a incorporação intracelular de uma ampla gama de íons. A sensibilidade e a capacidade de remoção de cádmio (Cd2+) de duas espécies de rizobactérias: Rizobium tropici (LBMP-C01) e Ensifer meliloti (LBMPC02), foram estudadas. A concentração mínima inibitória (CMI) das bactérias foi determinada pelo cultivo em meio contendo CdCl2.2H2O (0,025 a 4 mmol L-1). Foram realizados testes de viabilidade das células das duas estirpes na CMI e ensaios de bioacumulação com suspensões de células bacterianas nas doses de 10, 20 e 30 %(v/v) em solução contendo 100 mg L-1 de Cd2+. As estirpes LBMP-C01 e LBMP-C02 foram sensíveis a concentrações de Cd2+ superiores a 1,0 e 0,05 mmol L-1, respectivamente. As células de LBMP-C01 e LBMP-C02 apresentaram-se viáveis nas CMI 1,0 e 0,05 mmol L-1 Cd2+, respectivamente. A estirpe LBMP-C01 não removeu Cd2+ nos ensaios de bioacumulação e a estirpe LBMP-C02 foi capaz de remover 80 % deste íon em solução contendo 100 mg L-1 Cd2+, após 72 h de contato e 30 %(v/v) do bioacumulador. Os espectros de absorção molecular na região do infravermelho, de ambas as espécies estudadas praticamente não indicaram diferenças nos grupos funcionais presentes nas moléculas da biomassa celular. A observação por microscopia eletrônica de transmissão mostrou a presença de maior número de grânulos eletrodensos no citoplasma da estirpe de LBMP-C02 em relação à LBMP-C01 quando estas foram cultivadas com Cd2+. A estirpe LBMP-C02 foi a mais eficiente na remoção de Cd2+. A resistência a metais dessas duas bactérias envolve mecanismos diferentes. / Rhizobacteria are excellent candidates for use in the processes of bioaccumulation of potentially toxic elements because they have developed mechanisms for the intracellular uptake of a wide range of ions. Here, the sensitivity and capacity to remove cadmium (Cd2+) of two species of rhizobacteria, Rhizobium tropici (LBMP-C01) and Ensifer meliloti (LBMP-C02), were studied. The minimum inhibitory concentration (MIC) of the bacteria was determined by culturing them in medium containing CdCl2·2H2O (0.025 to 4 mmol L-1 ). Cell viability tests of the two strains were performed at MIC, and bioaccumulation assays were performed with 10, 20, and 30 %(v/v) bacterial cell suspensions in a Cd2+ solution 100 mg L-1 . Strains LBMP-C01 and LBMP-C02 were sensitive to Cd2+ concentrations above 1.0 and 0.05 mmol L-1 , respectively. LBMP-C01 and LBMP-C02 cells were viable at the MICs of Cd2+ solution 1.0 and 0.05 mmol L-1 , respectively. LBMP-C01 did not remove Cd2+ in the bioaccumulation assays, whereas LBMP-C02 removed 80 % of this ion in Cd2+ solution 100 mg L-1 , after 72 h of contact and 30 %(v/v) of the bioaccumulator. The infrared absorption spectra of both species did not indicate differences in the functional groups present in the molecules of the cell biomass. Transmission electron microscopy showed the presence of a larger number of electron-dense granules in the cytoplasm of LBMP-C02 compared to LBMP-C01 when they were cultured with Cd2+. The LBMP-C02 strain was the most efficient in the Cd2+ removal. The metal resistance of these two bacteria involves different mechanisms.

As a potential bioremediation system for contaminated soils, I evaluated the use of an arbuscular mycorrhizal (AM) fungus, Glomus intraradices on roots and shoots uptake of polycyclic aromatic hydrocarbons (PAHs), alkyl PAHs, and toxic metals in Echinacea purpurea, in using a controlled 20-week greenhouse study and a complimentary 2-year field study. E. purpurea seeds were either inoculated with the mycorrhizal fungus (AM) or not inoculated (non-AM) and grown in soil provided by the National Capital Commission (NCC) that have known contamination. In the greenhouse study, AM inoculation increased the uptake of alkyl PAHs in the roots of E. purpurea. The AM inoculation showed no effect on root uptake of PAHs and toxic metals over the 20-week study period. However, when I calculated the uptake rates (k1) for PAHs between both treatments, the AM treated roots ha 10-fold higher k1 values than non-AM treated roots. The soil concentrations of PAHs were found to increase over time with AM inoculation, suggesting, that AM fungi are causing a solvent depletion through root uptake of minerals and carbon, which concentrates the more hydrophobic PAHs in soils. Alkyl PAHs and metals showed no change over time amongst any of the treatments. Assessing the performance of AM fungi on the uptake of contaminants under field conditions, only PAHs showed increased bioaccumulation in the shoots of E. purpurea with AM inoculation. Alkyl PAHs and metals in plant material were unaffected by the AM inoculation, but increased significantly from year 1 to year 2. The uptake rates among treatments were similar, with non-AM roots having slightly greater uptake. Soil concentrations of PAHs and alkyl PAHs were unaffected over the course of the experiment. Our control soil, however, showed significant increases in concentration from year 1 to year 2 with alkyl PAHs. These results quantified the influence of AM hyphae-mediated uptake of organic and inorganic contaminant transfer from soil to plants and the bioaccumulation kinetics for contaminants by E. purpurea that will be useful for environmental models and phytoremediation strategies.

Inorganic contaminants, including potentially toxic metals (PTMs), originating from un-reclaimed abandoned mine areas may accumulate in soils and present significant distress to environmental and public health. The ability to generate realistic spatial distribution models of such contamination is important for risk assessment and remedial planning of sites where this has oc-curred. This study evaluated the prediction accuracy of optimized ordinary kriging compared to spatial regression-informed cokriging for PTMs (Zn, Mn, Cu, Pb, and Cd) in soils near abandoned mines in Bumpus Cove, Tennessee, USA. Cokriging variables and neighborhood sizes were system-atically selected from prior statistical analyses based on the association with PTM transport and soil physico-chemical properties (soil texture, moisture content, bulk density, pH, cation exchange capacity (CEC), and total organic carbon (TOC)). A log transform was applied to fit the frequency histograms to a normal distribution. Superior models were chosen based on six diagnostics (ME, RMS, MES, RMSS, ASE, and ASE-RMS), which produced mixed results. Cokriging models were preferred for Mn, Zn, Cu, and Cd, whereas ordinary kriging yielded better model results for Pb. This study determined that the preliminary process of developing spatial regression models, thus enabling the selection of contributing soil properties, can improve the interpolation accuracy of PTMs in abandoned mine sites.

Accumulation of heavy metals in different environmental compartments and their toxicity even at trace level concentration necessitates the study of their efficient removal. Furthermore, metals could co-exist in the environment which is a complex scenario as there would be competition among the metals in terms of removal efficiency. This study presents the effective removal of trace level toxic metals (Hg2+, Cd2+, Pb2+) in both single and ternary metal solutions through adsorption on the successfully synthesized composite (SC) of pinewood-derived biochar (BC) and graphene oxide (GO) nanomaterials. Moreover, different linear regression tools (Gaussian Process (GP), Random Forest (RF), and Feed Forward Back Propagation (FFBP)) from the machine learning (ML) toolbox were used to make the comparison between actual and their predicted adsorption. The structural and morphological analysis of the SC showed that GO was successfully coated on the surface of the BC. GO coating increased the surface area, porosity, functional groups, and adsorption efficiency of these toxic metals on the SC as compared to the unmodified BC. The factors affecting adsorption efficiency were metal concentration, pH, and the ratio of BC and GO in the SC. The adsorption efficiency in single metal solution was found 94-98% for Hg2+, 92-94% for Cd2+, and 96-99% for Pb2+ and for ternary metal solutions 94-96% for Hg2+, 95-97% for Cd2+, and 97-99% for Pb2+ at pH 6 and SC with BC/GO (w/w) ratio as 1:10. However, for unmodified BC, the adsorption efficiency was less in both single and ternary solutions. Thus, results indicate that modification of BC with GO increases adsorption efficiency as compared to unmodified BC. Furthermore, for all three metals, Freundlich's adsorption isotherm was followed in both single and ternary solutions. Regeneration of the SC was also attained by adsorbate desorption, producing a competent and cost-effective adsorbent for the removal of toxic metals from our environment. Furthermore, from the ML toolbox mean squared error (MSE) values between the actual efficiency and predicted efficiency were calculated which was negligible in the case of GP, with regression coefficient (R2) equal to 1. This implied that GP was the most suitable linear regression model among other models (RF, FFBP) for the available data sets. These predicted values through different ML models could significantly reduce the experimental workload for various parameters in predicting the removal efficiency of the synthesized composite for the target toxic metals. Thus, these models help in reducing experimental time and predicting the most appropriate combination for the best result in the future.

The exploitation of metallic sulfide ores produces vast quantities of fine-grained wastes hosting potentially toxic elements (PTEs). There are concerns that, if improperly disposed of and managed, waste mineral particles can behave as vectors that disperse PTEs via aeolian and fluvial transport, subsequently contaminating soils and crops used to support human populations. The importance of these particles, as sources and influencers of PTE biogeochemistry in productive soils, has received limited research. Long-term (365 d) batch incubation experiments, field weathering experiments and phytoavailability trials, were performed to establish the rate, patterns and factors limiting PTE (Cd, As, Hg) release from grains of sphalerite (Zn(Fe,Cd)S), arsenopyrite (FeAsS) and cinnabar (HgS) into soil matrices (0.1 % mineral:soil m/m), and the bioavailability of the liberated PTEs to important food crops (Tricitum aestivum, wheat and Oryza sativa, rice). All three of the ores underwent chemical weathering in oxic agricultural soils of both temperate and sub-tropical provenance, during which nonessential PTEs (cadmium, mercury, arsenic) were released in bioavailable forms, at rates relevant to agricultural production. Sphalerite weathered at a rate of 0.6 to 1.2 % a-1 (Cd basis) in the experimental soils, releasing 0.5 to 1 μmol Cd g-1 ZnS a-1 into the soil matrix. Cinnabar weathering reached a maximum of 12.0 – 13.5 % (Hg basis) after 90 days exposure in oxic soils, whereas arsenopyrite weathering was rapid and extensive, reaching 56 to 66 % (S basis) after 180 days. The PTE concentrations accumulated in edible grains of wheat and rice grown in the sulfide-contaminated soils were higher than international food safety limits by factors of 8 (Cd in rice), 10 – 30 (Hg in wheat and rice) and 8 – 12 (As in wheat and rice). The primary geochemical factors controlling PTE release and bioavailability were solid-phase associations (i.e. PTEs complexed by clays, metal oxyhydroxides and organic matter) and the precipitation of secondary mineral phases. Weathering arsenopyrite grains were passivated from further oxidation by secondary iron-arsenate phases, which also co-precipitated arsenic liberated from the ore. Secondary phase formation was identified as the cause of decreasing extractable Hg (liberated from cinnabar) after mercury release from cinnabar peaked (≤ 90 days exposure). For sphalerite, the evidence indicates that secondary sulfide phases formed under flooded (sulfate-reducing) soil conditions (paddy rice), limited the bioavailability of cadmium previously liberated under oxic conditions. These key findings demonstrate a potential human health hazard relating to the dispersal of PTE-hosting sulfide ore particles produced by mining activities into soils supporting human populations via crop contamination. This work also highlights differences in ore geochemistry, showing the need for additional research on different ore minerals and their alteration products.

Atmospheric aerosols are a highly relevant component of the climate system affecting atmospheric radiative transfer and the hydrological cycle. As opposed to other key atmospheric constituents with climatic relevance, atmospheric aerosol particles are highly heterogeneous in time and space with respect to their size, concentration, chemical composition and physical properties. Many aspects of their life cycle are not understood, making them difficult to represent in climate models and hard to control as a pollutant. Aerosol-cloud interactions in particular are infamous as a major source of uncertainty in future climate predictions. Field measurements are an important source of information for the modeling community and can lead to a better understanding of chemical and microphysical processes. In this study, field data from urban, marine, and arid settings are analyzed and the impact of meteorological conditions on the evolution of aerosol particles while in the atmosphere is investigated. Particular attention is given to organic aerosols, which are a poorly understood component of atmospheric aerosols. Local wind characteristics, solar radiation, relative humidity and the presence or absence of clouds and fog are found to be crucial factors in the transport and chemical evolution of aerosol particles. Organic aerosols in particular are found to be heavily impacted by processes in the liquid phase (cloud droplets and aerosol water). The reported measurements serve to improve the process-level understanding of aerosol evolution in different environments and to inform the modeling community by providing realistic values for input parameters and validation of model calculations.

Nas últimas décadas o crescimento industrial decorrente do desenvolvimento tecnológico e outras atividades consideradas indispensáveis à vida humana, estão gerando graves problemas ambientais, que está despertando uma preocupação a nível mundial. Dentre os vários contaminantes os metais tóxicos têm recebido atenção especial, pela sua persistência ao ingressar nos ecossistemas acumulando-se por toda a cadeia alimentar, uma vez que são extremamente tóxicos, mesmo em quantidades muito baixas. No Brasil, a legislação ambiental vigente já estabelece normas bastante rigorosas no que diz respeito ao descarte de águas contaminadas por metais tóxicos. Para que o tratamento deste tipo de efluentes seja feito adequadamente, e para que possam ser impostos limites máximos cada vez mais compatíveis com a sustentabilidade da vida moderna, torna-se relevante a preocupação com novas tecnologias mais eficientes e econômicas que permitam a remoção de metais tóxicos do ambiente contaminado. Hoje o tratamento do ambiente contaminado é realizado empregandose tecnologias convencionais baseadas em princípios físico-químicos, as quais estão sendo consideradas ineficientes e economicamente inviáveis. Alternativamente, uma nova tecnologia, a biorremediação, vem ganhando cada vez mais importância, devido às vantagens que oferece: simplicidade, eficiência e baixo custo. Para isto é necessário ser avaliada a utilização de microorganismos resistentes e eficazes na remoção do metal, pois, nesta fase são necessários que sejam selecionados organismos com características favoráveis ao processo. Dentro deste contexto, a proposta desse projeto foi isolar e caracterizar micro-organismos de uma área de mineração, avaliando os mecanismos e estratégias para o seu uso na remediação de áreas contaminadas a fim de otimizar a sua capacidade de adsorver íons de metais tóxicos, com vistas à utilização destas bactérias para a biossorção de efluentes de mineração. Foram isoladas e identificadas 105 cepas resistentes a cobre, destas 12 cepas foram capazes de crescer à 7.5 mM de cobre. Experimentos de adsorção com metais tóxicos (Cu, Cd e Ni) mostraram que tais cepas são promissoras na ampliação de tecnologias para uma mineração menos impactante, como a exploração de fontes de metais em baixa concentração, transformando o resíduo em fonte de extração economicamente viável e ambientalmente favorável. / Recently, technological development has been resulted in an industrial growth and has been creating serious environmental problems as concern worldwide. Toxic metals have received special attention among many others contaminants, because their persistence in ecosystems and their capability of accumulation throughout the food chain (even in low amounts). Environmental legislation in Brazil has very strict standards regarding discharge of toxic metals contaminated water. For a successful treatment of such effluents, it is relevant to concern about new technologies more efficient and economics to allow the removal of metals heavy from contaminated environment. Today the treatment of contaminated area is carried out conventional technologies based on physicochemical principles, which are inefficient and uneconomical. Alternatively, a new technology, called bioremediation, is being more important due to the advantages it offers: simplicity, efficiency and low cost. Bioremediation may be a viable alternative for areas contaminated by toxic metals. It\'s needed to evaluate the use of resistant and effective microorganisms in removing the metal, because it\'s required to be selected organisms with favorable characteristics for the process. In this context, the aim of this project is isolating and characterizing microorganisms from a mining area, evaluating the mechanisms and strategies for using in the remediation of contaminated areas, in order to optimize its adsorb heavy metal ions ability and use these bacteria for bioremediation of mining effluents. This work isolated and identified 105 strains resistant to copper, 12 of them were able to grow up to 7.5 mM copper, adsorption experiments with toxic metals (Cu, Cd and Ni) showed that these strains are promising in expanding technologies for sustainable mining, such as the exploitation of low concentration metal sources, turning waste into economically viable mining and environmentally friendly.