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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Remoção de bisfenol-A por adsorção

Haro, Nathalia Krummenauer January 2013 (has links)
O bisfenol-A (BPA), um monômero usado na fabricação de resinas epóxi e de plásticos de policarbonato, é considerado um potente desregulador endócrino que provoca diversas doenças. O objetivo deste trabalho foi estudar a remoção de BPA, de soluções aquosas através da técnica de adsorção em batelada e em processo contínuo. Também foi investigada a capacidade de regeneração do sorvente utilizado nos testes em batelada. Para isso, foram testados diferentes adsorventes (zeólita em pó e granular modificada com quitosana, zeólita sódica e carvão ativado granular), a fim de determinar qual apresentaria maiores índices de remoção de BPA. Posteriormente foram realizados ensaios de sorção com o sólido escolhido objetivando encontrar as condições mais adequadas de processo considerando os parâmetros de pH, tempo de residência, concentração de sólido sorvente. Ainda, isotermas de equilíbrio para este sistema foram construídas. A adsorção em leito fixo foi avaliada em experimentos via planta piloto de adsorção, segundo a influência de três variáveis: efeito da massa de adsorvente utilizada (5g e 10g), vazão de alimentação (15 mL.min-1 e 20 mL.min-1) e concentração inicial (50 mg.L-1 e 100 mg.L-1). Na regeneração do carvão ativado saturado com BPA, empregaram-se como solventes acetona, n-pentano e diclorometano e também foi utilizada a técnica de ultrassom. As condições de sorção utilizadas foram: pH 6, tempo 60 min, concentração de sorvente 10 g.L-1 e soluções de BPA 10 mg.L-1. A microestrutura externa e a composição elementar semi-quantitativa do carvão ativado antes e após o processo de sorção e regeneração foram analisadas pela técnica de MEV-EDS. No que se refere à sorção, melhores resultados foram encontrados com o carvão ativado granular, atingindo eficiência de remoção de 56,7% em pH 7. O modelo de isoterma de sorção que melhor se ajustou aos dados experimentais foi o modelo de Sips, que forneceu a constante de energia ou afinidade do processo e também a acumulação máxima de BPA no sorvente. Os testes de regeneração mostraram que os melhores agentes regenerativos foram a acetona (100%), com eficiência de remoção de 105,6% e a técnica de ultrassom, a qual apresentou uma eficiência de remoção de 106,4% após um tempo de contato de 30 min. Por ser uma técnica que não gera resíduo, optou-se utilizar o ultrassom para os testes de regeneração em ciclos. O ensaio de tempo de regeneração em banho de ultrassom mostrou que para os tempos de 30, 40, 50 e 60 min de contato a regeneração era muito semelhante. Assim, para os testes de ciclos de sorção-regeneração o tempo de contato utilizado foi de 30 min. Os ensaios de regeneração em ciclos mostraram que após seis (6) ciclos a eficiência de regeneração do sólido sorvente foi de 67,8% e a remoção de BPA obtida ao final desses ciclos foi de 60,9%. Quanto à caracterização do sorvente, as micrografias mostraram que o carvão ativado, antes e após os ciclos de sorção/regeneração (S/R), possui superfícies bastante irregulares, heterogêneas e desordenadas, com elevada porosidade. Ensaios realizados em planta piloto de adsorção mostraram a viabilidade técnica de aplicação do carvão ativado para remoção de bisfenol em processos contínuos, tendo sido possível obter as condições operacionais e a curva de ruptura do sistema. Os resultados indicaram que a adsorção em leito fixo apresentou melhores resultados nas seguintes condições: vazão de alimentação de 20 mL.min-1, concentração inicial de 100 mg.L-1 e 10g de sólido sorvente. / The bisphenol-A (BPA), a monomer used in the manufacture of epoxy resins and polycarbonate plastics is considered a powerful endocrine disrupter which causes various diseases. The objective of this work was to study the removal of BPA from aqueous solutions by adsorption technique in batch and continuous process. The regeneration capacity of sorbents used in batch tests was also investigated. For this purpose, different adsorbents were initially tested (zeolite powder and granular modified with chitosan, sodium zeolite and granular activated carbon) in order to determine which one presents higher removal rates of BPA. After that, sorption tests were carried out with the chosen solid aiming to find the best process conditions considering pH, residence time and sorbent concentration. Hence, equilibrium isotherms were constructed for this system. The fixed bed adsorption was evaluated through adsorption experiments using a pilot plant, according to the influence of three variables: the effect of the mass of the used adsorbent (10g and 5g), flow rate (15 mL.min-1 and 20 mL.min-1) and initial concentration (50 mg.L-1 and 100 mg.L-1). In activated carbon regeneration it was employed acetone, n-pentane and dichloromethane as solvents and the ultrasound technique was also used. The applied sorption conditions were the following: pH 6, time 60 min, sorbent concentration of 10 g.L-1 and BPA solution of 10 mg.L-1. The external microstructure and semi-quantitative elemental composition of the activated carbon before and after the sorption and regeneration were analyzed by SEM-EDS technique. Concerning sorption, the best results were found with granular activated carbon, reaching removal efficiency of 56.7% at pH 7. The sorption isotherm model that best fit the experimental data was the Sips model, which provided constant energy or affinity of the process and also the maximum accumulation of BPA in the sorbent. The regeneration tests showed that the best agents of regeneration were acetone (100%), with removal efficiency of 105.6% and the ultrasound technique, which presented a removal efficiency of 106.4% after a contact time of 30 min. Considering that the technique doesn’t generates waste, it was decided to use the ultrasound tests for regeneration cycles. The regeneration test time in ultrasound bath showed that for contact times of 30, 40, 50 and 60 min the regeneration was very similar. Thus, for testing cycles of sorption-regeneration, the used contact time was 30 minutes. The regeneration cycle tests showed that after six (6) cycles of regeneration efficiency of the solid sorbent was 67.8% and the removal of BPA obtained at the end of these cycles was 60.9%. Regarding characterization of the sorbent, the micrographs showed that the activated carbon before and after cycles of sorption/regeneration (S/R), has very irregular, heterogeneous and disordered surfaces with high porosity. Tests carried out in a pilot plant adsorption showed the technical viability of application of the activated carbon for removal of bisphenol in continuous processes, thus it is possible to obtain operating conditions and the breakthrough curve for this system. These results indicate that the fixed bed adsorption presents best results in the following conditions: feed flow rate of 20 mL.min-1, initial concentration of 100 mg.L-1 and 10 g of solid sorbent.
42

Electrochemical deposition of Graphene Oxide- metal nano-composite on Pencil-Graphite Electrode for the high sensitivity detection of Bisphenol A by Adsorptive Stripping Differential Pulse Voltammetry

Ghaffari, Nastaran January 2018 (has links)
Magister Scientiae - MSc (Chemistry) / Electrochemical platforms were developed based on pencil graphite electrodes (PGEs) modified electrochemically with reduced graphene oxide metal nanoparticles (ERGO-metalNPs) composite and used for the high-sensitivity determination of Bisphenol A (BPA) in water samples. Synergistic effects of both reduced Graphene Oxide sheets and metal nanoparticles on the performance of the pencil graphite electrode (PGE) were demonstrated in the oxidation of BPA by differential pulse voltammetry (DPV). A solution of graphene oxide (GO) 1 mg mL-1 and 15 ppm of metal stock solutions (1,000 mg L-1, atomic absorption standard solution) (Antimony or Gold) was prepared and after sonication deposited onto pencil graphite electrodes by cyclic voltammetry reduction. Different characterization techniques such as FT-IR, HR-SEM, XRD and Raman spectroscopy were used to characterize the GO and ERGO-metalNPs. Parameters that influence the electroanalytical response of the ERGO-SbNPs and ERGO-AuNPs such as, pH, deposition time, deposition potential, purging time were investigated and optimized. Well-defined, reproducible peaks with detection limits of 0.0125 ?M and 0.062 ?M were obtained for BPA using ERGO-SbNPs and ERGO-AuNPs respectively. The rGO-metalNPs-PGE was used for the quantification of BPA in tap water sample and proved to be suitable for the detection of BPA below USEPA prescribed drinking water standards of 0.087 ?M. / 2021-12-31
43

Análise comparativa dos padrões de proliferação e morte celular na próstata ventral de gerbilos sob os efeitos do bisfenol A e cádmio em condições androgênicas normais e após a orquiectomia = Comparative analysis of proliferation and cell death patterns in the ventral prostate of gerbils under the effects of bisphenol A and cadmium in androgenic normal conditions and after orchiectomy / Comparative analysis of proliferation and cell death patterns in the ventral prostate of gerbils under the effects of bisphenol A and cadmium in androgenic normal conditions and after orchiectomy

Colleta, Simone Jacovaci, 1989- 27 August 2018 (has links)
Orientador: Sebastião Roberto Taboga / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T10:30:24Z (GMT). No. of bitstreams: 1 Colleta_SimoneJacovaci_M.pdf: 4304217 bytes, checksum: ec5dd4758c1bcc8948cc085490014e3d (MD5) Previous issue date: 2015 / Resumo: A próstata é uma glândula acessória do sistema reprodutor que apresenta desenvolvimento e manutenção regulados por andrógenos e estrógenos. Interferências na ação desses hormônios podem predispor esta glândula a desenvolver doenças como hiperplasia prostática benigna e câncer. O bisfenol A (BPA) e cádmio (Cd) são poluentes ambientais que possuem atividade estereogênica. O BPA e Cd entram no corpo humano, principalmente através da ingestão oral. Assim, o objetivo deste estudo foi avaliar se a exposição ao BPA e ao Cd durante a puberdade pode causar alterações na morfologia, proliferação e morte celular na próstata ventral de gerbilos normais e castrados. Para cumprir estes propósitos foram realizadas técnicas morfológicas, serológicas e immunocitoquímicas (PCNA para detecção de células proliferativas e TUNEL/ caspase-3 para a detecção de células apoptóticas). Os resultados demonstraram que 7 dias depois da exposição ao BPA e Cd, individualmente ou em combinação sob condições androgênicos normais, houve um aumento na altura do epitélio e na espessura da camada muscular lisa (SML). O BPA e Cd individualmente induziram o aumento expressão celular de PCNA e caspase-3. Em associação, o BPA e Cd causam aumento das células imunomarcados por TUNEL. Nos animais castrados, o Cd, individualmente ou em associação com o BPA causou aumento na altura do epitélio, na espessura SML, na área e perímetro nuclear, além da redução no numero de células epiteliais imunomarcadas com PCNA. Além disso, o BPA e Cd combinados, causaram redução das células imunomarcadas por caspase-3. Após 75 dias depois da exposição ao BPA e Cd individualmente ou em combinação, nos animais não castrados, foi observado um aumento na altura epitelial e na espessura da SMC. Todos animais com 120 dias de idade apresentaram focos de lesões intraepitelial prostática (PIN). O BPA promoveu redução da expressão de PCNA nas células do estroma. O Cd, individualmente ou associado com o BPA, causou um aumento das células epiteliais imunomarcadas por PCNA. Além disso, Cd aumentou o numero de células imunomarcadas por TUNEL e diminuiu as células imunomarcadas por caspase-3. Nos animais castrados, a administração BPA e Cd, individualmente ou em combinação, promoveu aumento das células imunomarcadas por TUNEL. Desta forma, podemos concluir que o BPA e o Cd são importantes desreguladores das atividades normais do tecido prostático, alterando os padrões morfológicos, de proliferação e morte celular / Abstract: The prostate is an accessory reproductive system gland presenting the development and maintenance regulated by androgens and estrogens. Interference in the action of these hormones may predispose this gland to develop diseases such as benign prostatic hyperplasia and cancer. The Bisphenol A (BPA) and cadmium (Cd) are environmental pollutants that have estrogenic activity. The BPA and Cd enter in human body, mainly through oral ingestion. Thus, the aim of this study was to evaluate whether exposure to BPA and the Cd during puberty can cause alterations in morphology, proliferation and cell death in normal and castrated gerbils¿ ventral prostate. For this, morphological, serological and immunocitochemical (PCNA for proliferating cells detection and TUNEL/ caspase-3 for apoptotic cells detection) methods were used. The results demonstrated that 7 days after the exposure to BPA and Cd, individually or in combination under androgenic normal conditions, there was an increase in epithelium height and in smooth muscle layer (SML) thickness. The BPA and Cd individually induced increased in PCNA and caspase-3 cellular expression. In association, the BPA and Cd cause increase in TUNEL immunostained cells. In castrated animals, the Cd, individually or in association with the BPA caused an increase in epithelium height, in SML thickness, in area and nuclear perimeter, in addition caused reduction in PCNA immunostained epithelial cells number. In addition, BPA and Cd combined, caused reduction in caspase-3 immunostained cells. Seventy-five days after BPA and Cd exposure, individually or in combination, in non-castrated animals, we observed an increase in epithelial height and the SMC thickness. All animals with 120 days of age had occurrences of lesions prostatic intraepithelial (PIN). The BPA caused a reduction in PCNA stromal cells expression. The Cd, individually or associated with BPA, caused an increase in PCNA immunostained epithelial cells. In addition, Cd increased the number of immunostained cells by TUNEL and decreased the immunostained cells by caspase-3. In castrated animals, the administration BPA and Cd, individually or in combination, increased the immunostained cells by TUNEL. We can conclude that the BPA and Cd are are important agents in endocrine activities changing of normal prostatic tissue patterns, altering the morphological, proliferation and cell death patterns / Mestrado / Histologia / Mestra em Biologia Celular e Estrutural
44

Estudo da degradaÃÃo de policarbonato de bisfenol A (PCBFA) de garrafÃes de Ãgua mineral / Study on the degradation of bisphenol A polycarbonate (PCBFA) bottles of mineral water

Fabricio Siqueira Queiroz 30 August 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O policarbonato de bisfenol A (PCBFA) à um poliÃster, com repetiÃÃo de estrutura quÃmica das molÃculas de bisfenol A (BFA), que acumula um conjunto bem balanceado de propriedades, tais como: transparÃncia, estabilidade tÃrmica e dimensional, resistÃncia mecÃnica, antichama; permitindo classificÃ-lo como plÃstico de engenharia. Ele à um material utilizado em garrafÃes retornÃveis para acondicionamento de Ãgua mineral. O processo de fabricaÃÃo dos garrafÃes à de grande importÃncia, pois objetiva a produÃÃo de um material uniforme, que de certa maneira garante qualidade para resistir Ãs intempÃries do tempo e aos diversos processos de envasamento de Ãgua, estocagem e distribuiÃÃo. Os ÃrgÃos governamentais regulamentaram que o tempo de vida Ãtil das embalagens à somente de trÃs anos. A validade da Ãgua em garrafÃes lacrados varia de 60 a 120 dias. Depois de aberto, a recomendaÃÃo à consumir em atà duas semanas. A degradaÃÃo do PCBFA foi estudada utilizando garrafÃes de 20 litros de diferentes anos de fabricaÃÃo (0-15 anos), observou-se o efeito do tempo na mudanÃa das caracterÃsticas e propriedades do material. Verificou-se que a espessura dos garrafÃes diminui com o tempo de fabricaÃÃo. A partir de 8 anos de fabricaÃÃo, possÃveis mudanÃas estruturais, como a descarboxilaÃÃo, diminuiÃÃo da temperatura de transiÃÃo vÃtrea e alteraÃÃo nas propriedades mecÃnicas foram constatadas atravÃs das tÃcnicas de infravermelho (FTIR), Calorimetria ExploratÃria Diferencial (DSC) e por ensaios mecÃnicos de traÃÃo, respectivamente. Por microscopia eletrÃnica de varredura (MEV), verificou-se que a superfÃcie externa apresentou-se com mais alteraÃÃes morfolÃgicas em relaÃÃo à superfÃcie interna. Por anÃlise termogravimÃtrica (TGA), notou-se que o PCBFA da superfÃcie interna tem uma menor estabilidade tÃrmica que a superfÃcie externa do garrafÃo. Por anÃlise de fluorescÃncia foi detectada a presenÃa de BFA em Ãgua destilada mantida em contato com o garrafÃo estocada durante 2 meses. O BFA à o reagente utilizado na sÃntese industrial do PCBFA onde o mesmo à um desregulador endÃcrino que causa alteraÃÃes hormonais no sistema endÃcrino. Pode-se concluir que os garrafÃes de PCBFA sofrem degradaÃÃo com o passar dos anos a ponto do material perder suas principais propriedades, tanto na superfÃcie externa e interna. A relevÃncia maior do estudo evidencia sobre a validade dos garrafÃes e a possÃvel liberaÃÃo de BFA na Ãgua. / The polycarbonate of bisphenol A (PCBFA) is a polye ster with repeating chemical structure of molecules of bisphenol A (BFA), which accumulates a well-balanced set of properties, such as transparency, thermal and dimen sional stability, mechanical strength, flame retardant; allowing classify it as engineerin g plastic. It is a material used in returnable carboys for packaging of mineral water. The manufacturing process of the carboys is of great importance, because it aims the production of a uniform material, which somehow ensures quality to withstand the incl ement weather of weather and the various processes of potting water, stocking and di stribution of carboys. Government agencies have regulated that the time of validity o f the carboys is only three years. The validity of water in sealed bottles ranges from 60 to 120 days. Once opened, the recommendation is to consume within two weeks. The degradation was studied using PCBFA of 20 liters carboys of different fabrication years (0-15 years), we observed the effect of time in changing of the characteristics a nd properties of material. It was found that the thickness of carboys lowers with time of f abrication. From 8 years of manufacturing, possible structural changes, such as decarboxylation, reduction in glass transition temperature and changes in mechanical pr operties were observed via infrared techniques (FTIR), differential scanning calorimetr y (DSC) and tensile test, respectively. By scanning electron microscopy, it w as found that the external surface appeared with more morphological changes in relatio n to the inner surface. By thermogravimetric analysis (TGA), it was noted that the PCBFA the inner surface has a lower thermal stability than the outer surface of t he carboy. By fluorescence analysis, we detected the presence of BFA in distilled water kept in contact with the stored carboy for 2 months. BFA is the reagent used in the industrial synthesis of PCBFA where it is an endocrine disrupter which causes hor monal changes in the endocrine system. It can be concluded that the polycarbonate carboys undergo degradation with passing of the years to the point of the material l osing its main properties, both the outer and inner surface. The most relevant study demonstr ates the validity of carboys and the possible release of BFA in the water
45

Análise dos efeitos tóxicos do nonilfenol e do bisfenol A em organismos de água doce / The effects of nonylphenol and bisphenol A on freshwater organisms

Mariângela Spadoto 15 February 2013 (has links)
O bisfenol A (BPA) e o nonilfenol (NP), presentes em detergentes, pesticidas, plásticos e resinas, são conhecidos como Endocrine Disrupting-Chemicals (EDCs), Disruptores ou Desreguladores Endócrinos (DE) ou ainda Perturbadores Endócrinos ou Interferentes Endócrinos. O desregulador endócrino pode ser definido como uma substância química exógena ou mistura, que promove alterações em uma ou mais funções do sistema endócrino e na sua estrutura, causando, conseqüentemente, efeitos adversos na saúde de um organismo, ou a sua descendência. Esses compostos estão presentes nas águas de abastecimento, nos efluentes domésticos e industriais. Os desreguladores endócrinos têm ação mimética aos hormônios tanto no sítio de ligação quanto nos efeitos provocados nos seres vivos a eles expostos. Os compostos bisfenol A e nonilfenol foram identificados como desreguladores endócrinos em inúmeros trabalhos em diversos países, porém sendo pouco os efeitos em organismos tropicais. Este estudo teve como objetivo avaliar a toxicidade aguda do bisfenol A e do nonilfenol para Daphnia similis e Ceriodaphnia silvestrii, bem como, a toxicidade crônica para Ceriodaphnia silvestrii e Chironomus xanthus. Nos testes de toxicidade aguda com BPA os valores de CE(I)50; 48h foram de 10,64 mg/L para Daphnia similis e 19,9 mg/L para Ceriodaphnia silvestrii. Nos testes crônicos o valor do CEO obtido para Ceriodaphnia silvestrii foi 1,29 mg/L e para Chironomus xanthus 12 mg/L e o CENO 6 mg/L. Nos testes de toxicidade aguda feitos com NP, os valores de CE(I)50; 48h foram de 0,309 mg/L para Daphnia similis, 0,4520 mg/Lpara Ceriodaphnia silvestrii com solvente água e 0,0541 mg/L com solvente etanol, e 0,03398 mg/L para Ceriodaphnia dubia. O valor do CEO para Ceriodaphnia silvestrii foi 0,0198 mg/L e para Chironomus xanthus foi 100 \'mü\'g/g, com CENO de 50 \'mü\'g/g. Apesar das concentrações encontradas nos testes serem maiores que as encontradas nos estudos que quantificaram esses compostos no ambiente, outros estudos demonstraram que, mesmo em concentrações inferiores as obtidas nesse estudo já ocorrem problemas relacionados com o tempo da muda e com a androgenização do metabolismo de cladóceros. Além disso, a partir dos resultados obtidos com estes testes, pretende-se alertar o poder público sobre os riscos inerentes da presença destes produtos químicos nas águas e da urgência em se adotar novas técnicas no tratamento de efluentes visando à remoção eficaz desses poluentes. / Bisphenol A (BPA) and nonylphenol (NP), present in detergents, pesticides, plastics and resins, are known as Endocrine-Disrupting Chemicals (EDCs), Disruptors or Endocrine Disruptors (ED), Endocrine Disruption or Interferences Endocrine. The endocrine disruptors can be defined as an exogenous chemical substance or mixture, which causes changes in one or more functions of the endocrine system and its structure, causing, therefore, adverse effects on the health of an organism, or its progeny. These compounds are present in the water supply in domestic and industrial effluents. EDs have mimetic action to hormones in both binding site as the effects caused in living beings exposed to them. The compounds bisphenol A and nonylphenol were identified as endocrine disruptors in numerous studies in many countries, but with little effects on tropical organisms. This study aimed to evaluate the acute toxicity of bisphenol A and nonylphenol Daphnia similis and Ceriodaphnia silvestrii, as well as chronic toxicity to Ceriodaphnia silvestrii and Chironomus xanthus. In acute toxicity tests with BPA values EC(I) 50, 48 h were 10.64 mg/L for Daphnia similis and 19.9 mg/L for Ceriodaphnia silvestrii; chronic In the tests the value obtained for the CEO Ceriodaphnia silvestrii was 1.29 mg/L and 12 mg/L Chironomus xanthus CENO and 6 mg/L. In acute toxicity tests made with NP values EC(I) 50; 48h were 0.309 mg/L for Daphnia similis, 0.4520 mg/L for Ceriodaphnia silvestrii solvent and water with 0.0541 mg/L ethanol solvent and 0.03398 mg/L for Ceriodaphnia dubia. The value of the CEO to Ceriodaphnia silvestrii was 0.0198 mg/L and Chironomus xanthus was 100 \'mü\'g/g, with CENO was 50 \'mü\'g/g. Although the found concentrations in the tests are higher than those found in studies to have quantified these compounds in the environment, other studies showed that at concentrations lower than those obtained in this study have problems occur with time and the change of the metabolism of Cladocera androgenization. Also, based on the results obtained with these tests, is intended to alert the public on the risks associated of the presence of these chemicals in the water and the urgency in adopting new techniques in wastewater treatment aiming at the effective removal of these pollutants in water and in the sediment.
46

Mechanisms of transcriptomic and epigenetic responses to industrial pollutants in fish

Laing, Lauren Victoria January 2017 (has links)
Thousands of chemical pollutants enter the environment continuously, each with the potential to cause adverse effects in both terrestrial and aquatic organisms. As a result, organisms are often exposed to a mixture of stressors within their habitat. Populations of fish inhabiting most aquatic environments are exposed to time-varying or repeated pulses of exposure, driven by run-off events or spills, or due to their mobility between polluted and clean waters. Therefore, the sustainability of fish populations is critically dependent on their ability to adapt to frequent changes in their local environment. Despite this, legislation to protect the environment from chemical contamination are generally based on toxicological measurements following exposures to single stressors, conducted under optimal laboratory conditions, and that do not take into account the variation in susceptibility of wild populations, or the potential consequences of exposure for the susceptibility of the population during future exposures, including across generations. Increasing evidence is suggesting that a number of chemicals may interact with the epigenome, and that differential responses to pollutants may be modulated, at least in part, via epigenetic mechanisms. However, our understanding of the role of epigenetic mechanisms in normal development in fish models or its susceptibility to exposure to environmental stressors is currently very limited. This thesis aimed to document the mechanisms of genetic and epigenetic responses to industrial pollutants in fish, and to explore the extent to which differential responses can be induced in the lab following exposure during the critical window of embryonic development or in adults. To address these objectives, I performed a series of experiments using both the zebrafish (Danio rerio) and the three-spined stickleback (Gasterosteus aculeatus) as fish models. I first used the zebrafish (Danio rerio) model to investigate the sex-specific transcription and DNA methylation profiles for genes involved in the regulation of reproduction and in epigenetic signalling in the livers and gonads. I provide evidence of the sex-specific transcription of genes involved in reproduction and their regulation by epigenetic signalling in this commonly used vertebrate model and highlight important considerations regarding the use of whole tissues comprised of multiple cell types in epigenetic and transcriptomic studies. I then investigated the potential for exposure to Bisphenol A (BPA) to cause adverse effects on reproduction and to disrupt the expression profiles and promotor DNA methylation of target genes important for reproductive function and epigenetic signalling in the zebrafish. To do this, I exposed breeding zebrafish to a range of BPA concentrations over 15 days and found that BPA disrupted reproductive processes in zebrafish, likely via estrogenic mechanisms, but only at high concentrations. Importantly, exposure to environmentally relevant concentrations of BPA resulted in altered transcription of key enzymes involved in DNA methylation maintenance, and caused changes in promoter DNA methylation. I also conducted a series of repeated exposures to copper in the three-spined stickleback to investigate the extent to which differential susceptibility can be induced in the lab. This work provides evidence that pre-exposure to copper results in differential responses in future exposure scenarios both when the initial exposure occurred in adults and during embryogenesis. For adults, fish appeared to recover completely from the initial exposure following a period of depuration of 30 days, but displayed decreased susceptibility upon re-exposure. In contrast, for fish exposed during the critical windows of embryonic development when epigenetic reprogramming are hypothesised to occur, differential copper accumulation was maintained throughout life. Importantly, the initial exposure caused increased tolerance in the offspring, which was inherited up to the F2 generation. This work provides valuable information regarding potential critical windows of development which may be more susceptible to effects associated with pre-exposure, highlighting that early life exposure to a low concentration of copper can induce differential responses to copper across generations. These data highlight the extent of differential responses to chemical stressors likely to be present in wild populations, and point towards the possibility that effective population management will likely require an in-depth understanding of the exposure history of a given population in order to manage restocking initiatives, and to inform conclusions drawn from toxicity testing studies conducted using individuals originating from wild populations. In addition, these data suggest that it is likely that both epigenetic and genetic changes can contribute to the adaptation of individual populations to their local environment. Finally, other vertebrates including humans have been shown to be exposed to the chemicals tested in this thesis. Therefore, this highlights the potential for these chemicals to also cause toxic effects in humans, potentially via (epi) genetic mechanisms, and advocate the testing of the potential for inheritable phenotypes, such as those described in this thesis, to occur in mammalian models.
47

Desenvolvimento e validação de método analítico para análise de bisfenol A e nonilfenol em águas superficiais da cidade de Americana, SP / Development and validation of analytical method for analysis of bisphenol A and nonylphenol in surface waters of the city of Americana, SP

Daniele Alves de Souza Beraldo 20 April 2012 (has links)
Neste estudo determinou-se o nonilfenol - um composto xenobiótico utilizados na fabricação de antioxidantes, aditivos para óleos lubrificantes e produção de surfactantes etoxilados - e o bisfenol A - um composto químico utilizado na produção de diversos produtos, como, plásticos policarbonatos, resinas epóxi e retardantes de chama. Ambos exibem atividade estrogênica em concentrações abaixo de 1ng L-1 - em cinco pontos de coleta na cidade de Americana, SP. Devido à ampla utilização, esses compostos estão presentes em esgoto industrial em quantidades substanciais. A primeira etapa deste estudo foi a validação dos método analítico seguindo o Método 8270D da United States Environmental Protection Agency (USEPA) que descreve o procedimento de validação para os compostos semivoláteis analisados por cromatografia gasosa acoplada a espectrometria de massas (GC/MS). Os limites de detecção e de quantificação do método para a determinação do nonilfenol foram, respectivamente, 1 e 5 µg L-1. O coeficiente de determinação (R2) e a recuperação média para o nonilfenol foram, respectivamente, 0,99 e 99,04%. Os limites de detecção e de quantificação do método para o bisfenol A foram, respetivamente, 1 e 5 µg L-1. O coeficiente de determinação (R2) e a recuperação média para o bisfenol A foram, respectivamente, 0,99 e 91,55%. Na segunda etapa desta pesquisa analisaram-se amostras de água coletadas na cidade de Americana para a determinação do nonilfenol e do bisfenol A. Como método de extração dos compostos, usou-se a extração em fase sólida (SPE) e como técnica analítica a cromatografia gasosa acoplada a espectrometria de massas (GC/MS). Os resultados indicaram a presença desses compostos em alguns pontos de amostragem sendo que a concentração do nonilfenol a variou de 5,028 a 10,524 µg L-1 e para o bisfenol A a concentração variou de 5,645 a 295,255 µg L-1. Foram feitos também testes ecotoxicólogicos utilizando como organismo teste o microcrustáceo Daphnia similis, porém o nonilfenol e o bisfenol A, na concentração testada que variou de 0,05 a 500 µg L-1 não apresentaram toxicidade aguda. / In this study it was determined nonylphenol - a xenobiotic compound used in the manufacture of antioxidants, additives for lubricating oils and production of ethoxylated surfactant - and bisphenol A - a chemical compound used in production of various products, such as polycarbonate plastic, epoxy resins and flame retardants. Both exhibit estrogenic activity at concentrations lower than 1 ng L-1 - in five sampling points in the city of Americana, SP. Due to the widespread use of these compounds, they are present in substantial quantities in industrial sewage. The first step of this study was to validate the analytical method following the Method 8270D of the United States Environmental Protection Agency (USEPA) that describes the validation procedure for semi-volatile compounds analized by gas chromatography-mass spectrometry (GC/MS). The limits of detection and quantification for determining the nonylphenol were, respectively, 1 and 5 µg L-1. The coefficient ofdetermination (R2) and recovery for nonylphenol were respectively 0.99 and 99.04%. The limits of detection and quantification for the bisphenol A were, respectively, 1 and 5 µg L-1. The coefficient of determination (R2) and recovery for bisphenol A were respectively 0.99 and 91.55%. In the second step of this study were analized in water samples of Americana city for the determination of nonylphenol and bisphenol A. As a method of extraction of the compounds it was used solid-phase extraction (SPE) and as analytical technique GC/MS. The results indicated the presence of such compounds in some sampling points and the concentration of nonylphenol ranged from 5.028 to 10.524 µg L-1 and bisphenol A concentration ranged from 5.645 to 295.255 µg L-1. Ecotoxicological tests were also performed using as test organism microcrustaceans Daphnia similis, but nonylphenol and bisphenol A, tested at concentration ranging from 0,05 to 500 µg L-1 showed no acute toxicity.
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Remoção de bisfenol-A por adsorção

Haro, Nathalia Krummenauer January 2013 (has links)
O bisfenol-A (BPA), um monômero usado na fabricação de resinas epóxi e de plásticos de policarbonato, é considerado um potente desregulador endócrino que provoca diversas doenças. O objetivo deste trabalho foi estudar a remoção de BPA, de soluções aquosas através da técnica de adsorção em batelada e em processo contínuo. Também foi investigada a capacidade de regeneração do sorvente utilizado nos testes em batelada. Para isso, foram testados diferentes adsorventes (zeólita em pó e granular modificada com quitosana, zeólita sódica e carvão ativado granular), a fim de determinar qual apresentaria maiores índices de remoção de BPA. Posteriormente foram realizados ensaios de sorção com o sólido escolhido objetivando encontrar as condições mais adequadas de processo considerando os parâmetros de pH, tempo de residência, concentração de sólido sorvente. Ainda, isotermas de equilíbrio para este sistema foram construídas. A adsorção em leito fixo foi avaliada em experimentos via planta piloto de adsorção, segundo a influência de três variáveis: efeito da massa de adsorvente utilizada (5g e 10g), vazão de alimentação (15 mL.min-1 e 20 mL.min-1) e concentração inicial (50 mg.L-1 e 100 mg.L-1). Na regeneração do carvão ativado saturado com BPA, empregaram-se como solventes acetona, n-pentano e diclorometano e também foi utilizada a técnica de ultrassom. As condições de sorção utilizadas foram: pH 6, tempo 60 min, concentração de sorvente 10 g.L-1 e soluções de BPA 10 mg.L-1. A microestrutura externa e a composição elementar semi-quantitativa do carvão ativado antes e após o processo de sorção e regeneração foram analisadas pela técnica de MEV-EDS. No que se refere à sorção, melhores resultados foram encontrados com o carvão ativado granular, atingindo eficiência de remoção de 56,7% em pH 7. O modelo de isoterma de sorção que melhor se ajustou aos dados experimentais foi o modelo de Sips, que forneceu a constante de energia ou afinidade do processo e também a acumulação máxima de BPA no sorvente. Os testes de regeneração mostraram que os melhores agentes regenerativos foram a acetona (100%), com eficiência de remoção de 105,6% e a técnica de ultrassom, a qual apresentou uma eficiência de remoção de 106,4% após um tempo de contato de 30 min. Por ser uma técnica que não gera resíduo, optou-se utilizar o ultrassom para os testes de regeneração em ciclos. O ensaio de tempo de regeneração em banho de ultrassom mostrou que para os tempos de 30, 40, 50 e 60 min de contato a regeneração era muito semelhante. Assim, para os testes de ciclos de sorção-regeneração o tempo de contato utilizado foi de 30 min. Os ensaios de regeneração em ciclos mostraram que após seis (6) ciclos a eficiência de regeneração do sólido sorvente foi de 67,8% e a remoção de BPA obtida ao final desses ciclos foi de 60,9%. Quanto à caracterização do sorvente, as micrografias mostraram que o carvão ativado, antes e após os ciclos de sorção/regeneração (S/R), possui superfícies bastante irregulares, heterogêneas e desordenadas, com elevada porosidade. Ensaios realizados em planta piloto de adsorção mostraram a viabilidade técnica de aplicação do carvão ativado para remoção de bisfenol em processos contínuos, tendo sido possível obter as condições operacionais e a curva de ruptura do sistema. Os resultados indicaram que a adsorção em leito fixo apresentou melhores resultados nas seguintes condições: vazão de alimentação de 20 mL.min-1, concentração inicial de 100 mg.L-1 e 10g de sólido sorvente. / The bisphenol-A (BPA), a monomer used in the manufacture of epoxy resins and polycarbonate plastics is considered a powerful endocrine disrupter which causes various diseases. The objective of this work was to study the removal of BPA from aqueous solutions by adsorption technique in batch and continuous process. The regeneration capacity of sorbents used in batch tests was also investigated. For this purpose, different adsorbents were initially tested (zeolite powder and granular modified with chitosan, sodium zeolite and granular activated carbon) in order to determine which one presents higher removal rates of BPA. After that, sorption tests were carried out with the chosen solid aiming to find the best process conditions considering pH, residence time and sorbent concentration. Hence, equilibrium isotherms were constructed for this system. The fixed bed adsorption was evaluated through adsorption experiments using a pilot plant, according to the influence of three variables: the effect of the mass of the used adsorbent (10g and 5g), flow rate (15 mL.min-1 and 20 mL.min-1) and initial concentration (50 mg.L-1 and 100 mg.L-1). In activated carbon regeneration it was employed acetone, n-pentane and dichloromethane as solvents and the ultrasound technique was also used. The applied sorption conditions were the following: pH 6, time 60 min, sorbent concentration of 10 g.L-1 and BPA solution of 10 mg.L-1. The external microstructure and semi-quantitative elemental composition of the activated carbon before and after the sorption and regeneration were analyzed by SEM-EDS technique. Concerning sorption, the best results were found with granular activated carbon, reaching removal efficiency of 56.7% at pH 7. The sorption isotherm model that best fit the experimental data was the Sips model, which provided constant energy or affinity of the process and also the maximum accumulation of BPA in the sorbent. The regeneration tests showed that the best agents of regeneration were acetone (100%), with removal efficiency of 105.6% and the ultrasound technique, which presented a removal efficiency of 106.4% after a contact time of 30 min. Considering that the technique doesn’t generates waste, it was decided to use the ultrasound tests for regeneration cycles. The regeneration test time in ultrasound bath showed that for contact times of 30, 40, 50 and 60 min the regeneration was very similar. Thus, for testing cycles of sorption-regeneration, the used contact time was 30 minutes. The regeneration cycle tests showed that after six (6) cycles of regeneration efficiency of the solid sorbent was 67.8% and the removal of BPA obtained at the end of these cycles was 60.9%. Regarding characterization of the sorbent, the micrographs showed that the activated carbon before and after cycles of sorption/regeneration (S/R), has very irregular, heterogeneous and disordered surfaces with high porosity. Tests carried out in a pilot plant adsorption showed the technical viability of application of the activated carbon for removal of bisphenol in continuous processes, thus it is possible to obtain operating conditions and the breakthrough curve for this system. These results indicate that the fixed bed adsorption presents best results in the following conditions: feed flow rate of 20 mL.min-1, initial concentration of 100 mg.L-1 and 10 g of solid sorbent.
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Análise dos efeitos tóxicos do nonilfenol e do bisfenol A em organismos de água doce / The effects of nonylphenol and bisphenol A on freshwater organisms

Spadoto, Mariângela 15 February 2013 (has links)
O bisfenol A (BPA) e o nonilfenol (NP), presentes em detergentes, pesticidas, plásticos e resinas, são conhecidos como Endocrine Disrupting-Chemicals (EDCs), Disruptores ou Desreguladores Endócrinos (DE) ou ainda Perturbadores Endócrinos ou Interferentes Endócrinos. O desregulador endócrino pode ser definido como uma substância química exógena ou mistura, que promove alterações em uma ou mais funções do sistema endócrino e na sua estrutura, causando, conseqüentemente, efeitos adversos na saúde de um organismo, ou a sua descendência. Esses compostos estão presentes nas águas de abastecimento, nos efluentes domésticos e industriais. Os desreguladores endócrinos têm ação mimética aos hormônios tanto no sítio de ligação quanto nos efeitos provocados nos seres vivos a eles expostos. Os compostos bisfenol A e nonilfenol foram identificados como desreguladores endócrinos em inúmeros trabalhos em diversos países, porém sendo pouco os efeitos em organismos tropicais. Este estudo teve como objetivo avaliar a toxicidade aguda do bisfenol A e do nonilfenol para Daphnia similis e Ceriodaphnia silvestrii, bem como, a toxicidade crônica para Ceriodaphnia silvestrii e Chironomus xanthus. Nos testes de toxicidade aguda com BPA os valores de CE(I)50; 48h foram de 10,64 mg/L para Daphnia similis e 19,9 mg/L para Ceriodaphnia silvestrii. Nos testes crônicos o valor do CEO obtido para Ceriodaphnia silvestrii foi 1,29 mg/L e para Chironomus xanthus 12 mg/L e o CENO 6 mg/L. Nos testes de toxicidade aguda feitos com NP, os valores de CE(I)50; 48h foram de 0,309 mg/L para Daphnia similis, 0,4520 mg/Lpara Ceriodaphnia silvestrii com solvente água e 0,0541 mg/L com solvente etanol, e 0,03398 mg/L para Ceriodaphnia dubia. O valor do CEO para Ceriodaphnia silvestrii foi 0,0198 mg/L e para Chironomus xanthus foi 100 \'mü\'g/g, com CENO de 50 \'mü\'g/g. Apesar das concentrações encontradas nos testes serem maiores que as encontradas nos estudos que quantificaram esses compostos no ambiente, outros estudos demonstraram que, mesmo em concentrações inferiores as obtidas nesse estudo já ocorrem problemas relacionados com o tempo da muda e com a androgenização do metabolismo de cladóceros. Além disso, a partir dos resultados obtidos com estes testes, pretende-se alertar o poder público sobre os riscos inerentes da presença destes produtos químicos nas águas e da urgência em se adotar novas técnicas no tratamento de efluentes visando à remoção eficaz desses poluentes. / Bisphenol A (BPA) and nonylphenol (NP), present in detergents, pesticides, plastics and resins, are known as Endocrine-Disrupting Chemicals (EDCs), Disruptors or Endocrine Disruptors (ED), Endocrine Disruption or Interferences Endocrine. The endocrine disruptors can be defined as an exogenous chemical substance or mixture, which causes changes in one or more functions of the endocrine system and its structure, causing, therefore, adverse effects on the health of an organism, or its progeny. These compounds are present in the water supply in domestic and industrial effluents. EDs have mimetic action to hormones in both binding site as the effects caused in living beings exposed to them. The compounds bisphenol A and nonylphenol were identified as endocrine disruptors in numerous studies in many countries, but with little effects on tropical organisms. This study aimed to evaluate the acute toxicity of bisphenol A and nonylphenol Daphnia similis and Ceriodaphnia silvestrii, as well as chronic toxicity to Ceriodaphnia silvestrii and Chironomus xanthus. In acute toxicity tests with BPA values EC(I) 50, 48 h were 10.64 mg/L for Daphnia similis and 19.9 mg/L for Ceriodaphnia silvestrii; chronic In the tests the value obtained for the CEO Ceriodaphnia silvestrii was 1.29 mg/L and 12 mg/L Chironomus xanthus CENO and 6 mg/L. In acute toxicity tests made with NP values EC(I) 50; 48h were 0.309 mg/L for Daphnia similis, 0.4520 mg/L for Ceriodaphnia silvestrii solvent and water with 0.0541 mg/L ethanol solvent and 0.03398 mg/L for Ceriodaphnia dubia. The value of the CEO to Ceriodaphnia silvestrii was 0.0198 mg/L and Chironomus xanthus was 100 \'mü\'g/g, with CENO was 50 \'mü\'g/g. Although the found concentrations in the tests are higher than those found in studies to have quantified these compounds in the environment, other studies showed that at concentrations lower than those obtained in this study have problems occur with time and the change of the metabolism of Cladocera androgenization. Also, based on the results obtained with these tests, is intended to alert the public on the risks associated of the presence of these chemicals in the water and the urgency in adopting new techniques in wastewater treatment aiming at the effective removal of these pollutants in water and in the sediment.
50

Bisphenol A Exposure, Adipogenic Mechanism and Effect on Childhood Adiposity

Hoepner, Lori A. January 2015 (has links)
Bisphenol A (BPA) is a common component in plastic consumer products and epoxy resin linings. Initially developed in the 1930s-40s as a synthetic hormone treatment, it is now widely considered an endocrine disrupting chemical (EDC). A growing body of epidemiological literature suggests that ubiquitous exposures to BPA may be contributing to the global epidemic of obesity, with children a particularly vulnerable population. Obesity in children, defined by a body mass index (BMI) greater than or equal to the 95th percentile for age and sex, is an epidemic of great concern in the United States. As with other chemicals, the prenatal and early life period are critical windows of exposure to BPA; however, the mechanism by which BPA may influence the development of body size in children remains unclear. Experimental studies have found that BPA influences adipogenesis in both murine and adult human preadipocyte cell lines and BPA is hypothesized to play a role in enhancing adipogenic regulation by nuclear receptors such as peroxisome proliferator-activated receptor gamma (PPARγ). While the timeline of the processes involved in adipogenesis in humans is not universally agreed upon, it is accepted that PPARγ is highly expressed in adipose tissue and considered to be the master regulator of adipogenesis. To answer the question of both timing and developmental origin of BPA effects on adipogensis, we employed both an epidemiological approach, and experimental methodologies using primordial cell lines, mesenchymal stem cells (MSCs). Our study characterizes early life exposures to BPA, explores the adipogenic mechanism of BPA in human MSCs via cellular morphometrics and PPARγ gene expression, and identifies associations between early life exposure to BPA and childhood obesity and adiposity. For our epidemiological assessments, we studied a birth cohort of African American and Dominican mother and child dyads in New York City. BPA was measured in spot urine samples collected during pregnancy and at child ages 3, 5, and 7 years, from mothers and children (n=568 dyads) in the Columbia Center for Children’s Environmental Health (CCCEH). We compared BPA concentrations across paired samples. We explored relationships between BPA and the class of phthalate chemicals, another common plasticizer. BPA was detected in nearly all urine samples from prenatal third trimester and childhood ages 3 years, 5 years and 7 years. Prenatal urinary BPA concentrations were significantly lower than postnatal urinary BPA concentrations (p<0.001). BPA and phthalate metabolites were correlated prenatally and at 3, 5, and 7 years (all p-values < 0.02). BPA concentrations were correlated with phthalate metabolite concentrations prenatally, and at 3, 5 and 7 years(all p-values < 0.05). Geometric means of BPA were higher among African Americans than among Dominicans in prenatal (p<0.01), 5 year (p<0.001) and 7 year (p=0.02) samples. Postnatal BPA concentrations were significantly higher among children with mothers who had never marrried marital status and were significantly higher in summer than in all other seasons (all p-values < 0.05). These findings reveal widespread BPA exposure in an inner-city minority population. Our in vitro experiment was a feasibility study which sought to determine whether exposure to BPA by human umbilical cord mesenchymal stem cells (HUMSC) induces morphological changes and PPARγ gene expression during adipogenesis. An anonymous sample of n=18 umbilical cords was collected at delivery from mothers registered at New York-Presbyterian Sloane Hospital for Women and New York-Presbyterian Allen Hospital in New York City. HUMSCs were harvested from umbilical cords using an adhesion technique. HUMSCs were then induced in culture to differentiate into adipocytes using: a standard differentiation induction mix medium, a negative vehicle control medium, a positive control medium and experimental control media. Differences in cell surface area and cell count in all cultures were assessed using ImageJ software (version 1.49n, 2014). Gene expression of PPARγ in all cultures was evaluated by RT-PCR. Cell morphometric results were based on 11,676 cells from 3 umbilical cord samples. PPARγ1 and PPARγ2 gene expression was assessed during differntiation phase and early terminal phase adipogenesis (0 to 72 hours). Cell morphometrics were assessed during middle to late terminal phase adipogenesis (days 14 and 21). No differences in cell count were observed for experimental conditions compared to standard induction medium. A significant decrease in surface area was seen in cells exposed to 100 μM concentration of BPA as compared to exposure to standard induction medium at day 14 (t=-37.02 p=0.001). Differences in cell surface area were not observed at day 21. A twofold increased expression of PPARγ1 was observed in cells exposed to 10 μM concentration of BPA by 72 hours of adipogenic induction which was higher than the increase in expression observed for cells exposed to the positive control induction medium containing 10 μM concentration of rosiglitazone. All induction media conditions had negligible effects on PPARγ2 expression. As BPA increases expression of PPARγ1 in HUMSCs during the transition into the early terminal differentiation phase of adipogenesis, HUMSCs may be an approximate target tissue for evaluating BPA effects in adipogenesis. Finally, using a longitudinal research design, we analyzed the possible effect of prenatal and postnatal BPA exposures, measured in urine, on childhood anthropometric outcome measures. Participants in the CCCEH have been followed since the third trimester of pregnancy, providing us with anthropometric data on children from birth through the age of seven years. Available anthropometric outcome measures include body mass index z-scores (BMIZ) at 5 and 7 years, as well as fat mass index (FMI), percent body fat (%BF), and waist circumference (WC) at 7 years. Prenatal urinary BPA concentrations were positively associated with child age 7 FMI (beta=0.31 kg/m2, p-value=0.04, [95%CI 0.01, 0.60]), %BF (beta=0.79, p-value=0.04, [95%CI 0.03, 1.55]), and WC (beta=1.29 cm, p-value=0.01, [95%CI 0.29, 2.30]). Child urinary BPA concentrations were not associated with childhood BMI or other anthropometric outcomes. As the prenatal exposures were associated with childhood measures of adiposity, prenatal BPA exposure may have an effect on adiposity as children age that cannot be determined by the use of BMI alone. Our results suggest BPA may contribute to the developmental origins of obesity and adiposity.

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