Nanoparticles are increasingly incorporated into consumer products because of their unique, size-dependent properties. Although these properties are commercially appealing, data are lacking regarding the fate and reactivity of nanoparticles once incorporated into materials. This information gap prevents accurate assessment of hazards that these materials potentially present to consumers and the environment. To address this concern, new research is needed to investigate the reactivity and transformations of nanoparticles. This dissertation describes the use of an electron transparent characterization platform to observe nanoparticle transformations. Nanoparticles were tethered to the surface of an analysis platform, exposed to a variety of conditions, and evaluated for reactivity and response. The characterization of silver nanoparticles revealed the generation of new daughter nanoparticles on surfaces in ambient humid conditions. Our observations showed that the transport of material is highly dependent on relative humidity and that pH equilibria drives the deposition of new particles and degradation. We discovered, by applying these findings to macro-silver objects, that bulk silver generates new nanoparticles on surfaces. This illuminated the possibility of other, yet undiscovered, naturally occurring nanoparticles. In the second model system, 1.5 nm gold nanoparticles were tethered by a robust metal oxide bond from the terminal group of the stabilizing ligand. This strategy facilitated precise control over thiol ligand removal using a dilute ozone oxidation. Tracking particle oxidation over time allowed us to gain unprecedented control over core exposure, size maintenance, and surface tethering. This platform was also utilized as a proof-of-concept for direct observation of transformations in complex media. Ligand and core transformations were monitored in a variety of biologically relevant conditions using tethered nanoparticles. Morphological and chemical transformations were characterized and correlated to results from solution monitoring. The use of a platform based approach to evaluating the reactivity of nanoparticles in the environment holds promise for evaluations of nanoparticles and their transformation products. The demonstration of monitoring reactivity in systems equilibria, carefully controlled transformations, or complex media shows the versatility of this strategy. Only through the use of this analysis platform was the direct observation of nanoparticle transformations possible. This dissertation includes previously published, unpublished, and co-authored materials. / 10000-01-01

For bioactive chemical classes, it is often assumed that environmental transformation eliminates associated ecosystem risks. However, for endocrine-active steroid hormones, modest changes in structure can have a significant influence on biological activity and thus, subtle environmental transformations can yield products with conserved, enhanced, or activity across different biological endpoints. The aim of this work was to explore the environmental fate of high potency, endocrine-active steroid hormones during natural or engineered water processes in order to test the hypothesis that steroid transformation products generated during these processes are likely to contribute to residual bioactivity often reported in water resources. Specifically, laboratory experiments were used to simulate chemical disinfection (e.g., chlorination) or natural processes (e.g., photolysis) to: (i) determine the rate and extent of steroid transformation, (ii) isolate and identify products that are formed, and (iii) evaluate products or product mixtures for biological activity. These experimental results can be used to help guide occurrence studies for any products of concern in the environment and also guide computational predictions or rationalizations of chemical reactivity. Ultimately, the goal is to expand upon our awareness and understanding of how these potent endocrine ligands behave in the environment and how they potentially affect ecosystem health. Chapter 2 discusses the reaction of glucocorticoids (GC)s with aqueous chlorine (effectively, HOCl) to simulate their fate during engineered drinking water and wastewater chemical disinfection. Numerous transformation pathways were unveiled, including interconversion of GCs (e.g., endogenous cortisol to synthetic prednisolone), production of known androgens in the adrenosterone class, and chlorination of GCs (e.g., formation of 9-chloro-prednisone). We also showed that other advanced processes (e.g., oxidation via ozonation) result in more complete degradation of such pollutants, and may be better alternatives to chemical disinfection at eliminating bioactive steroidal product formation. In Chapter 3, results of the direct photolysis of dienogest (DNG), a widely prescribed oral contraceptive agent, are presented to simulate its fate in natural sunlit surface waters and engineered photochemical treatment systems (e.g., UV disinfection systems). The major products (~ 80% of the converted mass in neutral aqueous solutions) were identified to be photohydrates resulting from photochemical-induced incorporation of water into parent DNG. These products were found to be prone to dehydration in the dark, and thus, a source of substantial DNG regeneration (~ 65% after 72 h in neutral solutions). Other minor, non-revertible products were also identified, including two known estrogens. Although minor in initial yield, these estrogens are likely to accumulate over time through repeated cycling between DNG and its photohydrates, and thus, dominate DNG long-term fate. It was also found that DNG undergoes an unusual photochemical rearrangement to produce a minor product with a novel tetracyclic ring system--the subject of Chapter 4. Further, the generality of this unique photorearrangement process was explored through extension to the photolysis of two other dienone pharmaceutical steroids (e.g., the androgens methyldienolone and dienedione). Surprisingly, despite the significant change in core steroidal structure, the rearrangement products retain some progesterone receptor (PR) and androgen receptor (AR) bioactivity (i.e., low-µM to sub-nm EC50 values). Again, these represent other non-revertible, minor products that are likely to accumulate over time, with likely adverse ecological consequences. Chapter 5 covers results arising from the direct photolysis of trenbolone acetate (TBA) metabolites in the presence of model nucleophiles (e.g., sodium azide, sodium thiosulfate, ammonium hydroxide, hydroxylamine, and humic acid), some of which would be expected to be present, along with TBA metabolites, in agriculturally-impacted water resources. Previous studies by our group revealed that TBA metabolites undergo photohydration-thermal dehydration cycling, like that described above for DNG photolysis. The objective of this study was to determine if other nucleophiles would outcompete water for photochemical incorporation across the TBA metabolite extended conjugation system. It was found that TBA metabolite photolysis results in photochemical (and at times thermal) addition of the nucleophile to the TBA metabolites. It was also found that the addition products undergo thermal elimination in the dark and contribute to TBA metabolite regeneration, and therefore, are expected to increase TBA metabolite persistence in water resources. Finally, Chapter 6 discusses the reactions of various trienone and dienone steroids with aqueous chlorine to simulate their fate during engineered drinking water and wastewater chemical disinfection. Single-step transformation pathways were unveiled for each steroid class, including 4-chlorination (trienones) and 9,10-epoxidation (dienones). Chlorination at position C-4 is known to enhance anabolic potency of androgenic steroids and the 9,10-epoxy products were found to undergo acid- or base-catalyzed ring-opening and aromatization to yield known estrogenic products. In addition, Chapter 7 provides conclusions and future directions, while Chapter 8 details the experimental methods and procedures used throughout this thesis. Collectively, the results presented herein confirm our overall hypothesis that steroid transformation products would be expected to contribute to residual biological activity often detected in water resources. Furthermore, the results indicate that the transformation of high potency pharmaceuticals does not automatically equate with reduction or elimination of hazards to exposed organisms, especially in cases where such compounds have potential to form products exhibiting diverse biological endpoints. More holistic approaches to risk assessment of such high potency environmental contaminants are needed in order to accurately assess the fate and effects of such emerging pollutant classes and their bioactive transformation products.

Made available in DSpace on 2014-06-11T19:33:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-10-21Bitstream added on 2014-06-13T18:44:54Z : No. of bitstreams: 1 fadini_aab_dr_rcla.pdf: 1079665 bytes, checksum: 7d6f17a8a616af61f4a85405317d2545 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo visa apresentar uma pauta para um planejamento ambiental e participativo em duas sub-bacias hidrográficas representativas da porção paulista e mineira do Compartimento Ambiental da Região Bragantina, considerando as transformações sócio-econômicas, ambientais e culturais que vem ocorrendo nesta localidade. A implantação e posterior duplicação de importantes rodovias como a D. Pedro I e a Fernão Dias, a construção dos reservatórios do Sistema Cantareira e a criação das Áreas de Proteção Ambiental - APA Piracicaba/Juqueri-Mirim, APA Cantareira e APA Fernão Dias - vêm provocando novos usos do solo, entre eles o processo de industrialização, de urbanização e de desenvolvimento turístico. Esta situação nos últimos anos tem acelerado as alterações na paisagem afetando diretamente o modo de vida e a identidade local dos atores sociais que vivem nestes lugares. Deste modo, buscou-se através da confecção por geoprocessamento de cartas temáticas, desenvolver um inventário, diagnóstico e análise dos usos históricos do solo, além da aplicação de um questionário-entrevista para identificar a percepção ambiental, a topofilia e a identidade dos atores sociais com o lugar de vivência. Espera-se que esta pauta voltada para as sub-bacias possa contribuir para a implantação de planos integrados e participativos para todo o Compartimento Ambiental da Região Bragantina, buscando uma sustentabilidade ambiental em escalas local e regional. / This study aims to present guidelines for an environmental and participatory planning in two representative water basins of the São Paulo and Minas Gerais states that integrate the Bragantina Region Environmental Compartment, considering the social, economic, environmental and cultural transformations that are occurring in this area. The construction and later duplication of important highways as the D. Pedro I and the Fernão Dias, the construction of the Cantareira Water Reservoir System and the creation of the Environmental Protection Areas - EPA Piracicaba/Juqueri-Mirim, EPA Cantareira and EPA Fernão Dias - are stimulating new uses of the soil, and among them can be highlighted the industrial, the urban and tourist development. This situation has in the last years increased the dynamics of landscape transformations affecting directly the way of life and the identity of the social actors who live in these areas. It is expected that the proposed guidelines can contribute to the development of integrated and participatory plans to the Bragantina Region Environmental Compartment, fostering sustainability at local and regional levels.

As práticas defendidas por conservacionistas ou preservacionistas convergem para um mesmo ponto, ou seja, a necessidade urgente em se desenvolver ações que possam garantir a existência dos recursos naturais para as gerações atuais e futuras. Neste sentido, a criação de espaços protegidos têm-se apresentado como uma solução plausível frente à degradação ambiental desencadeada ao longo do processo histórico da humanidade. A legislação ambiental brasileira, a rigor, espelha-se nas políticas definidas pelos países ocidentais, participando de acordos e tratados de cunho ambiental que englobam diversos países. No Brasil as Unidades de Conservação, como, por exemplo, os Parque, enfrentam problemas de diversas ordens, o que coloca em “xeque” a preservação e/ou conservação desses espaços; dentre esses problemas destacamse o uso do solo em seu entorno. No estado Tocantins, o Parque Estadual do Lajeado, objeto desta pesquisa, localizado no município de Palmas, encontra-se sobreposta a Área de Preservação Ambiental - APA Serra do Lajeado, esta por sua vez, deveria garantir a proteção do seu entorno, no entanto, devido à natureza jurídica da APAs, bem como, a ineficiência e inoperância dos órgãos fiscalizadores; têm-se observado a dilapidação do patrimônio natural do entorno do Parque Estadual do Lajeado. Neste contexto, a presente pesquisa, buscou elucidar como as transformações espaciais, os sujeitos e suas diferentes formas de uso do solo no entorno do Parque Estadual do Lajeado, têm ocasionado interferência na conservação ambiental e gestão desta unidade. Fato este evidenciado por meio da metodologia adotada, principalmente com o uso de imagens de satélite, no mapeamento do uso do solo no período de 2000 a 2015 e levantamentos de campo, onde observou-se que a principal pressão na área de pesquisa refere-se a expansão urbana e agricultura em larga escala. Com base no uso do solo e aplicação de modelos matemáticos, foi possível realizar-se uma projeção de diferentes cenários futuros para o entorno do Parque Estadual do Lajeado, com ênfase na questão ambiental. / The practices advocated by conservationists or preservationist converge towards the same point, that is, an urgent need to become actions that guarantee a natural resource existence for present and future generations. In this sense, the creation of protected spaces has been presented as a plausible solution to the environmental degradation triggered throughout the historical process of humanity. Brazilian environmental legislation, strictly speaking, is reflected in the policies defined by Western countries, participating in agreements and treaties of an environmental nature that encompass several countries. In Brazil, Conservation Units, such as the Parks, face problems of various kinds, which puts the preservation and / or conservation of these spaces in check; Among these problems the use of the soil in its surroundings stands out. In the state of Tocantins, the State Park of Lajeado, object of this research, located in the municipality of Palmas, is overlapped with the Area of Environmental Preservation - APA Serra do Lajeado, this in turn, should guarantee the protection of its surroundings, however , Due to the legal nature of the APAs, As well as the inefficiency and ineffectiveness of the supervisory bodies; Have been observed the dilapidation of the natural patrimony of the surroundings of the State Park of Lajeado. In this context, the present research sought to elucidate how the spatial transformations, the subjects and their different forms of land use in the surroundings of Lajeado State Park, have caused interference in the environmental conservation and management of this unit. This fact was evidenced through the methodology adopted, mainly with the use of satellite images, in the mapping of the land use in the period from 2000 to 2015 and field surveys, where it was observed that the main pressure in the area of research refers Urban sprawl and large-scale agriculture. Based on the use of the soil and the application of mathematical models, it was possible to carry out a projection of different future scenarios for the surroundings of the State Park of Lajeado, with emphasis on the environmental issue.