• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 60
  • 33
  • 18
  • 14
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 137
  • 50
  • 25
  • 20
  • 18
  • 18
  • 17
  • 16
  • 12
  • 11
  • 10
  • 9
  • 9
  • 8
  • 8
  • 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.
91

Manganês: o papel do fracionamento químico e da especiação como determinantes de seu comportamento geoquímico e neurotóxico nos organismos em desenvolvimento / Manganese: role of chemical fractioning and speciation as determinants of its geochemical and developmental neurotoxicological effect

Raúl Bonne Hernández 11 December 2009 (has links)
O manganês (Mn) é um elemento essencial, porém pode ser tóxico em concentrações acima do requerido fisiologicamente. Assim, motivado pelo aumento nos teores desse metal na bacia hidrográfica Alto do Paranapanema (ALPA) e o crescente número de estudos internacionais relacionando desordens neurológicas ao excesso de Mn em águas superficiais, o presente trabalho foi conduzido para avaliar o perfil geoquímico e neurotoxicológico do Mn nos organismos em desenvolvimento em função da especiação química do metal. Desta maneira, no período de agosto/2006 a abril/2007, foram realizadas quatro coletas de amostras de águas superficiais e de sedimentos, nos rios Paranapanema e Itapetininga e no reservatório Jurumirim, localizados na bacia hidrográfica Alto do Paranapanema (ALPA, SP). Os estudos de fracionamento químico demonstraram que na bacia ALPA o Mn ocorre basicamente nos sedimentos (Mn ligado a hidr(óxidos) de Fe e Mn > Mn ligado a carbonatos ≈ Mn intercambiável ≈ Mn ligado a silicatos > Mn ligado a matéria orgânica) porém em constante troca com a coluna líquida, onde o Mn ocorre como metal particulado e em menor proporção como metal lábil. Acredita-se que esse padrão de distribuição esteja governado pelas características oxidantes e alcalinas desses sistemas aquáticos. Adicionalmente, foi verificado que a origem do Mn nesses sistemas é de caráter natural, porém com ~ 30 % de riscos ecotoxicológicos. Neste sentido, estudos in vitro (modelos de neurônios) e in vivo (embriões de paulistinha, Danio rerio) com as espécies MnCl2, Mn(II)Cit, Mn(III)Cit, Mn(III)PPi (Cit: Citrato, PPi: Pirofosfato) sugeriram que o Mn(II) é mais tóxico do que o Mn(III). Contudo, independentemente da especiação química, o Mn foi mais tóxico para neurônios glutamatérgicos do cerebelo em diferenciação, e para o paulistinha no período embrio-larval, pós-eclosão (> 72 horas pós-fertilização), no qual foram verificados danos neuromusculares. No entanto, a espécie mais tóxica para embriões expostos por 48 h foi o MnCl2 e por 120 h o Mn(II)Cit, sugerindo que o citrato está mediando essa toxicidade, o que é uma exceção ao “Free Ion Activity Model”. Conforme esses resultados foram verificados inibição do metabolismo do lactato e do ascorbato in vitro. Estudos de expressão gênica no paulistinha, mediante RT-PCR qualitativo e quantitativo permitiram verificar alterações no gene mitocondrial mt-co1, que pode ser compensada pela superexpressão do gene hspb11. Esses resultados sugerem que os danos induzidos pelas espécies de Mn devem estar associados à disfunção mitocondrial e do metabolismo energético, seguido da indução de estresse oxi-redutivo, o qual pode ser parcialmente revertido pela administração exógena de lactato e/ou ascorbato, sendo propostos os prováveis mecanismos. A probabilidade de que esses eventos toxicológicos aconteçam em outras espécies, incluindo os seres humanos, é sustentada principalmente pelos estudos tóxico-genômicos, dado que em outras espécies podem ser encontrados ortologos para esses genes, e especialmente para mt-co1, que poderia ser um biomarcador da toxicidade do Mn. Finalmente, sugere-se que os valores de referência de Mn em sedimentos sejam revistos em função das contribuições de frações biodisponíveis, e que esses resultados sejam considerados pelas agências ambientais do Estado em seus programas de avaliação e gerenciamentos de riscos / Manganese (Mn) is an essential element, however it may be toxic in higher than recquired physiological levels. The present work was motivated by the increased levels of this metal in the Alto do Paranapanema (ALPA, São Paulo state) hydrographic basin and to the growing amount of international evidence relating neurological disorders to excess Mn in superficial waters. Therefore, experiments were conducted in order to evaluate Mn both geochemical and neurotoxicological profiles on the developmental stages of aquatic organisms and mammaliam models as a function of metal speciation. During August 2006 to April 2007, four expeditions to ALPA were performed to collect water and sediment samples from rivers Paranapanema and Itapetininga, as well as from Jurumirim reservoir. Chemical fractioning studies showed that Mn occurs mainly in sediments (Mn bound to Fe, Mn (hydr)oxides > Mn bound to carbonates ≈ Interchangeable Mn ≈ Mn bound to silicates > Mn bound to organic matter) but in constant exchange with the liquid column, where Mn occurs as particulated metal and, in lesser amounts, as a labile metal. This distribution pattern is thought to be governed by the oxidant and alkaline conditions of this aquatic system. Also, Mn was found to be of natural origin, however posing ~ 30% of ecotoxicological risks. In vitro (neuronal cells) and in vivo (zebrafish, Danio rerio embryos) studies with the species MnCl2, Mn(II)Cit, Mn(III)Cit, Mn(III)PPi (Cit: Citrate, PPi: Pyrophosphate) suggest that Mn(II) is more toxic than Mn(III). However, independently of chemical speciation, Mn was more toxic to cerebellar glutamatergic neurons during differentiation and to zebrafish in the embryo- larval period (> 72 hours pos-fertilization), to which neuromuscular damage was observed. The most toxic species for embryos exposed for 48 h was MnCl2, but in the 120 h exposition experiment Mn(II)Cit was more toxic, suggesting that citrate mediates the toxicity, in an exception to the Free Ion Activity Model. According to these results, it was observed inhibition in the metabolism of lactate and ascorbate in vitro. Gene expression studies of zebrafish were performed by both qualitative and quantitative RT-PCR, displaying changes in the expression of the mithocondrial gene mt-co1 which may be compensated by an overexpression of hspb11 gene. These results suggest that the damage induced by Mn species may be related to mitochondrial and energy metabolism disfunction followed by induction of oxi-reductive stress, which can be partially reverted by the exogenous administration of lactate and/or ascorbate. The putative mechanisms are proposed. The possibility that these toxic events might be important to other species, humans included, is substantiated mainly by the toxicogenomics studies, since ortologs for both genes are widespread. This is especially true to mt-co1, which may be a biomarker for Mn toxicity. Finally, it is suggested that the reference values of Mn in sediments should be revised to accomodate the contributions of bioavailable fractions, and that results should be considered by official environment control agencies during their evaluation and risk management programs
92

Pérennité, fonctionnalité, efficacité d'une zone humide artificielle (ZHA) en milieu méditerranéen : un nouvel écosystème au service du traitement secondaire des effluents industriels / Durability, functions, reliability of a constructed wetland in Mediterranean area : a novel ecosystem dedicated to secondary treatment of industrial wastewater

Petit, Marie-Eléonore 21 November 2017 (has links)
Les zones humides naturelles méditerranéennes sont des écosystèmes rares et vulnérables souvent altérés par les pollutions des milieux adjacents. Le développement de zones humides artificielles (ZHA) servant au traitement secondaire des pollutions permettrait de limiter l’impact des activités industrielles sur les milieux naturels. Pour végétaliser ces ZHA et tolérer les contraintes du climat méditerranéen, l’utilisation d’espèces végétales locales éco-adaptées est recommandée. Toutefois ce type de ZHA, utilisant des plantes locales méditerranéennes, a fait l’objet d’un nombre restreint de travaux. Les objectifs de cette thèse sont donc : - de suivre la biocénose implantée et spontanée d’une ZHA pour évaluer la mise en place de ce nouvel écosystème (suivis floristique, faunistique et phytoplanctonique),- d’évaluer ses fonctionnalités et son efficacité épuratoire (suivis physico-chimique et biologique),- de questionner la pérennité de tels systèmes dans une contexte de changements globaux, notamment climatique. Les résultats montrent qu’un nombre restreint d’espèces végétales locales sélectionnées peut permettre la création d’un nouvel écosystème fonctionnel et durable qui soutient l’enjeu de biodiversité, tout en améliorant le traitement des effluents rejetés par le bassin industrialisé. Ces travaux valident l’intérêt des ZHA à hélophytes locales en méditerranée pour traiter les pollutions de bassins versants industrialisés mais un effort de recherche reste à faire pour adapter la conception aux spécificités des sites dans une véritable démarche d’ingénierie écologique. / Natural wetlands in Mediterranean areas are rare and vulnerable ecosystems, frequently impacted by various pollutants from nearby environments. In order to decrease industrial activities lethal effects on natural areas, constructed wetlands (CWs) are an interesting opportunity to remediate their pre-treated wastewaters. Such CWs would take advantage with using local plant species, well adapted to Mediterranean climate’s rigors. Nevertheless, CWs planted with Mediterranean plant species are still scarce and poorly studied. Aims of this thesis are thus:• to follow up on planted and adventive biocœnosis of a CW (flora, fauna and phytoplankton), in order to assess a novel ecosystem settlement,• to get better knowledge on its functions and remediation efficiency (physico-chemical and biological parameters),• to question durability of such techno-ecosystems in a context of global changes (with focus on climate).Main result let us know that it only takes a few local plant species, wisely chosen, to allow the settlement of a sustainable and fully functional ecosystem, supporting biodiversity stakes while increasing the remediation of pre-treated wastewaters collected from industrialized catchment. This work assess CWs planted with local helophytes as a powerful tool to treat industrialized catchment wastewaters in Mediterranean area, but researches are still needed to fit each design with each site characteristics, following a sustainable ecological engineering approach.
93

Valuing ecosystem services - linking ecology and policy

Noring, Maria January 2014 (has links)
Ecosystem services constitute a precondition for human welfare and survival. This concept has also become increasingly popular among both scientists and policymakers. Several initiatives have been taken to identify and value ecosystem services. Several services are threatened, and it has been concluded that in order to better manage ecosystem services they need to be further investigated and valued. By measuring them using a common metric—monetary value—they can be more easily compared and included in decision-making tools. This thesis contributes to this goal by presenting values for several ecosystem services and also including them in decision-making tools. Starting with a discussion of the concept of ecosystem services, this thesis aims to present values for certain ecosystem services and to illustrate the use of these values in systems-analysis tools such as cost-benefit analyses (CBA) and a weighting set. Links between ecology, economics and policy are discussed within a broader framework of ecosystem services. Five papers are included, in which two contingent valuation studies (CV) have been used to find values for different ecosystem services. One valuation study is focused on the effects from tributyltin (TBT) in Swedish marine waters. In addition, a quantitative assessment framework has been developed in order to simplify analysis of environmental status, progress in environmental surveillance and the relevance of different measures. It is suggested that the framework should also be used when assessing the impacts of other substances affecting the environment. The second valuation study investigates the risk of an oil spill in northern Norway. The results have been included in two CBAs and a weighting set. The first CBA compares costs for remediation of polluted sediments, caused by TBT, with the benefits of reducing TBT levels. The second CBA compares costs and benefits for reducing the probability of an oil spill. The weighting set includes monetary values on a number of impact categories where marine toxicity is based on the valuation study on TBT.  One study also examines the inclusion of environmental costs in life cycle costing (LCC) in different sectors in Sweden. Results show that respondents consider ecosystem values to be important. The values of Swedish marine waters and coastal areas outside Lofoten-Vesterålen in Norway have been identified and quantified in terms of biodiversity, habitat, recreation and scenery. In the Norwegian case, an ongoing debate on the issue of oil and gas exploration has had an impact on the number of protest bids found in the study. Based on the cost and benefits of limiting impacts on ecosystem services derived from the valuation studies, CBAs show that the suggested measures are most likely beneficial for society, and the results contribute to policy recommendations. A weighting set has been updated with new values through value transfer. The weighting set is compatible with LCA. The final study shows that companies and public organisations use environmental costs (internal and external) in a limited manner. In this thesis the ecosystem service concept is used both as an introduction and a guiding thread for the reader, as a way to frame the studies undertaken. The concept of ecosystem services can be useful, as it emphasises the importance of the services to humans. By finding and presenting values of ecosystem services, such services are more easily incorporated into decision-making. / <p>QC 20141121</p>
94

Valorisation non alimentaire des huiles de friture usagées en tant que biolubrifiants / Non food valorisation of use frying oils as lubricants

Essono Abaga, Ange-Godefroy 06 December 2013 (has links)
Le projet de recherche appliquée portait sur la valorisation des huiles de friture usagées en tant que biolubrifiant pour chaîne de tronçonneuse. Ces huiles collectées dans les différentes enseignes de restauration présentent une teneur élevée en composés polaires, une acidité élevée, une grande variabilité dans leur composition en acides gras, relatives aux différentes marques d'huiles végétales utilisées. Ces mélanges d'huiles végétales (colza, tournesol, arachide, palme, coprah), déjà valorisés dans la filière des biocarburants, présentent des propriétés physico-chimiques intéressantes (indice de viscosité, biodégradabilité, composition en acides gras) qui leur permettraient de concurrencer les lubrifiants d'origine minérale ou végétale que l'on trouve sur le marché, notamment dans le secteur forestier. Un procédé d'ultrafiltration par membrane céramique a permis de réduire la teneur en composés polaires ainsi que l'acidité consécutive au procédé de friture profonde, tout en réduisant le phénomène de colmatage. L'utilisation de la méthodologie des surfaces de réponse a contribué à optimiser les paramètres de température, pression, porosité des membranes, afin d'améliorer les débits de filtration. La formulation de ce biolubrifiant à partir du mélange d'huiles obtenu, optimisé par plan de mélanges, a conduit à l'obtention d'un produit de grade ISO 150 dont les caractéristiques «filant», «adhésivité » et « point d'écoulement » répondent au cahier des charges. Une étude de biodégradabilité selon la norme OCDE 301B a montré que l'huile formulée est biodégradable à 90%, faiblement toxique selon les tests OCDE 201, 202, 203, et ne présente pas d'allergénicité / The applied research project focused on the valuation of used frying oils as bio-lubricant for chainsaw. Those collected in the various restaurant chains oils have a high content of polar compounds , high acidity , a great variability in their composition , fatty acids on different brands of vegetable oils . These mixtures of vegetable oils (rapeseed, sunflower , peanut, palm , coconut ) , already valued in the biofuels , have interesting physicochemical properties ( viscosity , biodegradability , fatty acid composition ) that would allow them to compete with lubricants mineral or vegetable that is found on the market, particularly in the forestry sector origin . A method of ceramic membrane ultrafiltration has reduced content of polar compounds and the subsequent acidity of the deep frying process , while reducing the clogging phenomenon . The use of response surface methodology has helped to optimize the parameters of temperature, pressure, porous membranes, to improve filtration rates . The formulation of this biolubricant from the mixture of oils obtained optimized plan mixtures led to the production of a product of ISO 150 grade which features " spinning ", " stickiness " and " pour point " meet the specifications . A study of biodegradability according to OECD 301B showed that formulated oil is 90% biodegradable , low toxicity tests according to OECD 201, 202, 203, and does not show allergenicity
95

Toxicidade aguda e risco ambiental do diflubenzuron para Daphnia magna, Poecilia reticulata e Lemna minor na ausência e presença de sedimento /

Souza, Jaqueline Pérola. January 2008 (has links)
Orientador: Joaquim Gonçalves Machado Neto / Banca: Julio Vicente Lombardi / Banca: Robinson Antonio Pitelli / Resumo: O inseticida diflubenzuron (DFB), comercializado como Dimilin®, é empregado em pisciculturas no tratamento de ecotoparasitoses em peixes. Este composto inibe a síntese de quitina, componente do exoesqueleto dos parasitas. A utilização deste inseticida se deve à sua baixa toxicidade aos peixes e eficácia no controle dos ectoparasitas. Porém, no ambiente aquático o DFB pode ser tóxico à espécies sensíveis e não-alvos, a concentração empregada no tratamento das ectoparasitoses é de 2 mg.L-1. Os objetivos deste estudo foram avaliar a toxicidade do DFB para as espécies de Daphnia magna, Poecilia reticulata e Lemna minor, classificar o produto quanto à sua toxicidade e risco ambiental e avaliar o efeito do sedimento na biodisponibilidade do DFB na água. Os organismos-teste foram submetidos a concentrações crescentes do inseticida em salas climatizadas do Laboratório de Ecotoxicologia da FCAV-UNESP. Os testes com D. magna foram realizados em volume de 10 mL a 20° C e cinco organismos neonatos por concentração, durante 48 horas na presença e ausência de sedimento. Os peixes (P. reticulata) foram expostos às concentrações do DFB por 96 horas em testes na presença e ausência de sedimento. O volume final foi de 3000 mL e cinco animais por concentração à 25° C. As plantas de L. minor foram expostas ao DFB por sete dias na presença e ausência de sedimento. O volume final foi de 100 mL e 12 frondes por concentração à 24° C. Os testes foram realizados com três réplicas incluindo o controle. As CE50-48h calculadas para D. magna foram de 0,56 μg.L-1 e 1,51 μg.L-1 na ausência e presença de sedimento respectivamente; as CL50-96h para P. reticulata foram 152,00 mg.L-1 e 277,83 mg.L-1 na ausência e presença de sedimento respectivamente; e as CE50-7dias para L. minor foram 459,50 mg.L-1 e 698,25 mg.L-1 na ausência e presença de sedimento respectivamente...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The insecticide diflubenzuron (DFB), marketed as Dimilin®, is used in fish farms to treat ectoparasites in fishes. This compound inhibits the chitin synthesis, exoskeleton component of the parasites. The use of this insecticide is due to its low toxicity for fish and effectiveness in the control of ectoparasites. However, the DFB in the aquatic environmental can be toxic to sensitive species and non-targed, the concentration used in the treatment of ectoparasites is 2 mg.L-1. The aims of this study were to evaluate the toxicity of the DFB for the species of Daphnia magna, Poecilia reticulata and Lemna minor, classify the product as to their toxicity and environmental risk and evaluate the effect of sediment on the bioavailability of the DFB in the water. The organisms-test were submitted to increasing concentrations of insecticide in air conditioned rooms of the Laboratory of Ecotoxicology FCAV-UNESP. Tests with D. magna were performed in volume of 10 mL at 20° C and five organisms neonates (6 and 24 hours of age) in each concentration, for 48 hours in the presence and absence of sediment. Fishes (P. reticulata) were exposed to concentrations of the DFB for 96 hours in tests in the presence and absence of sediment. The final volume was 3000 mL and five animals per concentration to 25° C. The plants of L. minor were exposed to the DFB for seven days in the presence and absence of sediment. The final volume was 100 mL and 12 fronds by concentration to 24° C. The tests were performed with three repetitions incluing the control. The EC50-48h estimeds for D. magna were 0.56 and 1.51 μg.L-1 in the absence and presence of sediment respectively; the LC50-96h for P. reticulata were 152.00 mg.L-1 and 277.83 mg.L-1 in the absence and presence of sediment respectively; and the EC50-7dias to L. minor were 459.50 mg.L-1 and 698.25 mg.L-1 in the absence and presence of sediment respectively...(Complete abstract, click electronic access below) / Mestre
96

Avalia??o do potencial t?xico de ?guas oriundas de irriga??o agr?cola no Baixo-A?u/RN: um problema socioambiental / Evaluation of the toxic potential of waters originated from agricultural irrigation in Baixo-A?u/RN: a socioenvironmental problem

Santos, Mycarla Nely Rodrigues dos 25 February 2013 (has links)
Made available in DSpace on 2014-12-17T15:55:04Z (GMT). No. of bitstreams: 1 MycarlaNRS_DISSERT.pdf: 3216830 bytes, checksum: 07e1141d9905a390774485aa58ed8641 (MD5) Previous issue date: 2013-02-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / For many decades the problematic raised about the indiscriminate use of pesticides in modern agriculture has incited the interest of many researchers to discover the effects caused by such products in the environment and consequently in the life of the ones which use that products (farmers) and those people who live in places next to the agricultural areas. Facing these facts, this research had the intention of comprehend the environmental perception of habitants of the Distrito Irrigado do Baixo-A?u (DIBA), located in the semiarid of Rio Grande do Norte, by using agro toxics and its possible environmental effects, as well as evaluate the levels of toxicity of waters from agricultural runoff in this region by using eco-toxicological exams with Ceriodaphnia silvestii. Were done 86 interviews with dwellers and farmers from DIBA. With the results reached in the evaluation of the interviews it was possible to identify that one of major problems is the inappropriate discard of empty packs of the pesticides used at that place. The samples collected for eco-toxicological evaluation showed a variation in its toxicity, once that the point of collect which receives waters from different cultures presented in four out of five samples toxicity for the tested species. Therefore, it concludes that the indiscriminate use of pesticides agricultural practice presented a potential to pollute to the irrigation waters, and the absence of elucidation by the farmers about the manipulation of these products contribute to the risk of environmental contamination and the possible decrease of the quality of life of the dwellers of the region / H? d?cadas a problem?tica levantada sobre o uso indiscriminado de pesticidas pela agricultura moderna tem despertado o interesse de muitos pesquisadores na busca dos efeitos causados por tais produtos no meio ambiente e, consequentemente na vida tanto daqueles que fazem uso destes produtos (agricultores) quanto aqueles indiv?duos que residem em regi?es pr?ximas a ?reas agr?colas. Diante disto, esta pesquisa teve o objetivo de compreender a percep??o ambiental de moradores do Distrito Irrigado do Baixo-A?u (DIBA), localizado no semi?rido norteriogradense, frente ao uso de agrot?xicos e seus poss?veis efeitos ambientais, bem como avaliar o grau de toxicidade de ?guas do escoamento agr?cola nesta regi?o atrav?s de testes ecotoxicolol?gicos com Ceriodaphnia silvestii. Um total de 86 entrevistas foi realizado com moradores e agricultores do DIBA. Com os resultados obtidos na avalia??o das entrevistas foi poss?vel identificar que um dos maiores problemas ? o descarte inadequado das embalagens vazias dos pesticidas utilizados no local. J? as amostras coletadas para avalia??o ecotoxicol?gica mostraram varia??o em sua toxicidade, sendo visto que o ponto de coleta que recebe ?guas de diferentes culturas apresentou em quatro das cinco amostras toxicidade para a esp?cie testada. Diante disto conclui-se que a utiliza??o indiscriminada de agrot?xicos pela pr?tica agr?cola apresentou potencial poluidor para ?guas de irriga??o, e que a falta de esclarecimento dos agricultores sobre a manipula??o destes produtos contribuem para o riso de contamina??o ambiental e poss?vel diminui??o da qualidade de vida dos moradores da regi?o
97

Teores naturais de metais pesados nos solos de referência do Estado de Pernambuco / Background concentrations of heavy metals in benchmark soils of Pernambuco State, Brazil

BIONDI, Caroline Miranda 26 March 2010 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2016-07-05T14:51:43Z No. of bitstreams: 1 Caroline Miranda Biondi.pdf: 739101 bytes, checksum: 70b649020ff8bda42d06423a8a5313c6 (MD5) / Made available in DSpace on 2016-07-05T14:51:43Z (GMT). No. of bitstreams: 1 Caroline Miranda Biondi.pdf: 739101 bytes, checksum: 70b649020ff8bda42d06423a8a5313c6 (MD5) Previous issue date: 2010-03-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Knowing the natural background concentration of heavy metals in soil is a fundamental step to estimate its contamination level. Such reference value supports the establishment of soil screening levels for contaminants in soil that may be used to identify areas needing further investigation. Thus to determine the natural background of metals in soils is essential not only to trigger the need for response actions but also to define soil guidelines adequate for monitoring and remediation. These guidelines must take in account the local pedological conditions. In this scenario, the work was carried out to determine the natural concentrations of chromium (Cr), lead (Pb), barium (Ba), cadmium (Cd), arsenic (As), mercury (Hg), iron (Fe), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), and e cobalt (Co) in order to define soil screening levels of metals for benchmark soils of Pernambuco State. The results showed that the metals concentrations followed the order: Fe, Mn, Ba, Cr, Zn, Pb, Cu, Ni, Co, Cd, As, and Hg. In general, such sequence was independent of the horizon analyzed. Natural concentration could not be directly related to the parent material since pedogenetical processes seem to influence the concentrations of Fe, Mn, Ba, Cr, Zn, Pb, Cd, As, and Hg. Such an association was found only to Cu, Ni, and Co. Most soils presented Cu, Co, Ni, and Zn at lower concentration than that in soils mainly derived from mafic rocks from other Brazilian regions. This corroborates that these metals are more directly related to iron magnesium minerals. According to Brazilian soil guidelines (CONAMA, 2009), Ba, Cr and Hg concentrations were higher than the Levels of Prevention and Intervention which justifies the need for determining local backgrounds concentrations aiming at building national guidelines. The Cd concentration in some surface horizons from Zona da Mata region suggests anthropogenic inputs. The natural concentrations determined for benchmark soils of Pernambuco can be used to define the screening level (natural concentration) for the State’s soils as settled by the national legislation. / Para considerar que um determinado solo está livre de contaminação, faz-se necessário conhecer os teores do metal neste solo em condição natural, sem introdução antrópica. Este valor de referência é a base para a definição de Valores Orientadores de Qualidade do solo. Portanto, a determinação de teores naturais de metais em solos é essencial para a construção de uma legislação que sirva de base ao monitoramento e remediação de áreas contaminadas e que seja adequada a realidade pedológica local. Neste contexto, o objetivo desta pesquisa foi determinar os teores naturais de (Cr), chumbo (Pb), bário (Ba), cádmio (Cd), arsênio (As), mercúrio (Hg), ferro (Fe), manganês (Mn), zinco (Zn), níquel (Ni), cobre (Cu) e cobalto (Co), como base de referência de qualidade para os solos do Estado de Pernambuco. De acordo com os resultados, os teores de metal nos solos de referência de Pernambuco seguiram a seguinte ordem: Fe, Mn, Ba, Cr, Zn, Pb, Cu, Ni, Co, Cd, As e Hg. Em geral, o teor natural de metais pesados não pode ser inferido diretamente do material de origem dos solos, visto que os processos pedogenéticos parecem ser um fator decisivo no teor de Fe, Mn, Ba, Cr, Zn, Pb, Cd, As e Hg. Apenas Cu, Ni e Co puderam ser diretamente relacionados ao material de origem. A maioria dos solos apresentou teores de Cu, Co, Ni e Zn menores que solos de outras regiões do país, com litologia mais máfica, o que corrobora que os teores destes elementos são mais diretamente relacionados aos minerais presentes no material de origem dos solos. Observou-se teores de Cr, Ba e Hg superiores aos Valores de Prevenção e de Intervenção estabelecidos pelo CONAMA (2009), corroborando a necessidade de um maior conhecimento das diversidades regionais para a elaboração de normas nacionais. Foram observados teores de Cd elevados em alguns horizontes superficiais da Zona da Mata, havendo uma provável contribuição de atividades humanas, especialmente pelo fato de que os valores nos horizontes subsuperficiais são baixos e não relacionados aos teores em superfície. Teores naturais de metais determinados nos solos podem ser utilizados como base para definição dos Valores de Referência de Qualidade para os solos de Pernambuco, de acordo com o preconizado pela legislação nacional.
98

Construção de microrreatores nanoestruturados para a degradação de diclofenaco sódico mediante fotocatálise heterogênea

CARNEIRO, José Vinícius Oliveira 01 September 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-04-25T14:08:17Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO José Vinícius O. Carneiro-Final (BC).pdf: 3473579 bytes, checksum: 53d2c12ba53b539b7c125ce7329018ff (MD5) / Made available in DSpace on 2017-04-25T14:08:17Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO José Vinícius O. Carneiro-Final (BC).pdf: 3473579 bytes, checksum: 53d2c12ba53b539b7c125ce7329018ff (MD5) Previous issue date: 2016-09-01 / Diante da necessidade de tratar os contaminantes emergentes (CEs) presentes em águas residuais, o presente trabalho surge como uma rota alternativa de processo terciário a ser implantada nas estações de tratamento de efluentes (ETEs) convencionais. A fotodegradação do diclofenaco de sódio (DCF) mediante processos oxidativos avançados (POA), ocorreu via fotocatálise heterogênea utilizando nanotubos de TiO2 (NTs de TiO2) como fotocatalisadores. Empregou-se um reator em batelada com fotocatalisadores em placa (NTs de TiO2 e NTs de TiO2-Au ) e um reator tubular carregado com um microrreator (fotocatalisador) dotado de NTs de TiO2 sensibilizado ou não com nanopartículas de ouro (NPs Au). A síntese dos NTs de TiO2 ocorreu pelo processo de anodização utilizando como substrato folhas de titânio metálico (Ti). As matrizes nanotubulares foram cristalizadas por tratamento térmico (400°C por 3h). A sensibilização com NPs de Au foi realizada in situ por redução através da radiação UV. A fotodegradação foi realizada a partir da irradiação do simulador solar NEWPORT modelo 67005 com uma lâmpada de Xenônio-Mercúrio (com potência calibrada para 1 SOL), na ausência ou presença de filtro (UV ou visível). A fase cristalina anatase dos NTs de TiO2 foi identificada pela difração de raios X (DRX). Foi estimada pelo refinamento de Rietveld uma cristalinidade de 77% para a superfície fotocatalítica, com a anatase (NTs de TiO2 cristalizados) representando 92,4% desta fase cristalina. A energia de band gap dos fotocatalisadores de 3,23 eV foi determinada pela espectroscopia de reflectância difusa. Através da microscopia eletrônica de varredura (MEVEDD) foi possível visualizar para a folha de Ti lisa, estruturas cilíndricas dos NTs de TiO2 que cresceram perpendicular ao substrato, apresentando um diâmetro médio de 78,87 nm e comprimentos na ordem de 2 µm, no caso da folha de Ti ondulada os NTs de TiO2 cresceram em direções variadas apresentando um diâmetro médio de 81,09 nm e comprimentos na ordem de 3 µm. A presença das NPs Au foi identificada pela espectroscopia de energia dispersiva (EDD). A determinação e quantificação de produto e reagente da fotocatálise heterogênea na degradação do DCF foram realizadas pela combinação de métodos analíticos (Cromatografia líquida de alta eficiência, Ressonância Magnética e Infravermelho por transformada de Fourier), obtendo uma conversão de 100% do DCF para testes no reator em batelada e de 37,0% no reator com recirculação para o melhor sistema fotocatalítico. Foi estimado através da análise de carbono orgânico total (COT) uma mineralização de 18,5% do DCF inicial para o sistema fotocatalítico mais eficiente utilizando o reator com recirculação. A ecotoxicidade do DCF e seus produtos de fotodegradação foi avaliada utilizando microcrustáceos (Artêmias Salinas) como bioindicador. / Faced with the need to address emerging contaminants (ECs) in waste water, this work is an alternative route of tertiary process to be implemented in conventional wastewater treatment plants (WTPs). Sodium diclofenac photodegradation (DCF) by advanced oxidation processes (AOP), occurred via heterogeneous photocatalysis using TiO2 nanotubes (TiO2 NTs) as photocatalysts. He employed a batch reactor with photocatalysts plate (TiO2 NTs and TiO2 - Au NTs) and a tubular reactor charged with a microreactor (photocatalyst) having TiO2 NTs sensitized or not with gold nanoparticles (NPs Au). The synthesis of TiO2 NTs occurred by anodization process using as substrate sheets of metallic titanium (Ti). The nanotubulares matrices were crystallized by heat treatment (400 ° C for 3h). The sensitization Au NPs was performed in situ by reduction by UV radiation. The photodegradation was carried from the irradiation NEWPORT solar simulator 67005 model with a xenon-mercury lamp (calibrated power for 1 SUN) in the absence or presence of filter (UV or visible). The anatase crystalline phase of TiO2 NTs was identified by X-ray diffraction (XRD). It was estimated by Rietveld refinement a crystallinity of 77% at the photocatalytic surface with anatase (TiO2 crystallized NTs) representing 92.4% of this crystalline phase. The energy band gap of 3.23 eV photocatalysts was determined by diffuse reflectance spectroscopy. By scanning electron microscopy (SEM-EDS) it was possible to view the Ti smooth sheet, cylindrical structures of TiO2 NTs that grew perpendicular to the substrate, with an average diameter of 78.87 nm and lengths in 2 µm order, in the case of the corrugated Ti sheet the TiO2 NTs grew in different directions with a mean diameter of 81.09 nm and lengths on the order of 3 µm. The presence of NPs Au was identified by energy dispersive spectroscopy (EDS). The determination and quantification of product and reactant of heterogeneous photocatalytic on the degradation of DCF were performed by a combination of analytical methods (high-performance liquid chromatography, Magnetic Resonance and Infrared Fourier transform ), whereby a conversion of 100 % DCF for testing in batch reactor and 37.0 % in the reactor for recirculating the best photocatalytic system. It was estimated by analyzing total organic carbon (TOC) a mineralization of 18.5 % of the initial DCF for more efficient photocatalyst system using the reactor with recirculation. The ecotoxicity of DCF and its photodegradation products was evaluated using microcrustaceans (Artemias Salinas) as bioindicator.
99

Remoção do antibiótico amoxicilina por biorreator com membrana operado em regime de pré-desnitrificação : avaliação do desempenho, identificação de subprodutos e análises ecotoxicológicas

Matsubara, Milena Emy January 2018 (has links)
Orientadora: Profª. Drª. Lúcia Helena Gomes Coelho / Coorientador. Prof. Dr.Eduardo Lucas Subtil / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, Santo André, 2018. / Os antibióticos têm sido detectados em diversos compartimentos ambientais em concentrações traço da ordem de ng L-1 e µg L-1. Mesmo em baixos níveis, compostos farmaceuticamente ativos podem afetar a saúde humana e animal. Dentre esses micropoluentes emergentes está a amoxicilina, um antibiótico do tipo penicilina ?-lactâmico muito prescrito e consumido ao redor do mundo. Frente aos problemas relacionados com a presença dessa substância no meio ambiente, em várias situações, faz-se necessária sua remoção. O MBR (biorreator com membranas submersas) é um dos sistemas de tratamento com potencial para remover compostos emergentes do efluente. O presente trabalho teve como objetivo avaliar a eficiência de um sistema MBR piloto para remover amoxicilina de efluente sintético. Para isto, foi montada uma unidade piloto de dois estágios (tanque anóxico e aeróbio) de fluxo contínuo. A operação do sistema se deu em três fases: (1) com vazão de 1 L h-1 e TDH de 40 h; (2) adicionando 100 µg L-1 de amoxicilina no afluente e (3) alterando a vazão da condição (2) para 2 L h-1 e TDH de 20 h. A inserção de amoxicilina no afluente não impactou na eficiência de remoção de demanda química de oxigênio (DQO) e carbono orgânico dissolvido (COD), nem no processo de nitrificação, mas limitou a desnitrificação possibilitando detectar nitrito nas Fases 2 e 3. A alteração do TDH reduziu a porcentagem de remoção de COD (de 84% para 66% da Fase 2 para Fase 3), mas não influenciou na eficiência de eliminação de DQO (>94%), N-NH4+ (>98%) e N-total (>72%). A remoção de amoxicilina reduziu de 80% para 54% com a mudança da vazão. Os mecanismos de remoção de amoxicilina mediados pela atuação do lodo (adsorção e biodegradação) representam a maior fração removida do antibiótico no MBR (66%), o biofilme atua em 3% e a hidrólise contribui com apenas 2% da remoção. Análises cromatográficas confirmaram a presença de cinco produtos de degradação no afluente do sistema. Foi avaliada a sensibilidade de Vibrio fischeri, Daphnia magna, algas Chlorella vulgaris e Raphidocelis subcaptata, sementes de alface (Lactuca sativa) e mostarda (Sinapis alba) e as bactérias Escherichia coli, Bacillus subtilis e Pseudomonas fluorescens. Os ensaios de ecotoxicidade mostraram que todos os organismos são influenciados, ao mesmo tempo, pelos efeitos positivos da composição do esgoto sintético como nutrientes e pelos efeitos negativos da ação da amoxicilina. O ensaio de respirometria mostrou que concentrações de 1 a 100 µg L-1 de amoxicilina não inibiram as bactérias heterotróficas presentes na biomassa do MBR, mas concentrações de 1 a 100 mg L-1 as inibem. / Antibiotics have been detected in several environmental compartments at trace concentrations of ng L-1 and ?g L-1. Even at low levels, pharmaceutically active compounds can impact human and animal health. Among these emerging micropollutants is amoxicillin, a ?-lactamic penicillin antibiotic much prescribed and consumed around the world. Facing the problems related to the presence of this substance in the environment, in several situations, it is necessary to be removed. The MBR (a bioreactor with submerged membranes) is one of the treatment systems with the potential to remove emerging compounds from the effluent. The present work aims to evaluate the efficiency of a MBR system pilot to remove amoxicillin from synthetic wastewater. For this, a continuous flow two-stage (anoxic and aerobic tank) pilot unit was set up. The system operation occurred in three phases: (1) with a flow of 1 L h-1 and HRT = 40 h; (2) adding 100 ?g L-1 of amoxicillin to the influent and (3) altering the flow rate from condition (2) to 2 L h-1 and HRT = 20 h. The addition of amoxicillin in the inffluent did not affect COD and DOC elimination efficiency nor the nitrification process, but limited denitrification and, thus, nitrite was detected in Phase 2 and 3. The HRT change reduced the COD removal percentage (from 84% to 66 % from Phase 2 to Phase 3), but did not influence COD removal efficiency (>94%), N-NH4+ (>98%) and N-total (>72%). The amoxicillin removal decreased from 80% to 54% with flow rate change. The removal mechanisms of amoxicillin mediated by sludge (adsorption and biodegradation) represent the largest removed fraction of the antibiotic in the MBR (66%), the biofilm acts in 3% and the hydrolysis contributes only 2% of antibiotic removal. Chromatographic analyzes confirmed the presence of five degradation products in the effluent. The sensitivity of Vibrio fischeri, Daphnia magna, Chlorella vulgaris and Raphidocelis subcaptata algaes, lettuce (Lactuca sativa) and mustard (Sinapis alba) seed and the bacterias Escherichia coli, Bacillus subtilis and Pseudomonas fluorescens were evaluated. Ecotoxicity assays have shown that all organisms are influenced at the same time by the positive effects of the synthetic wastewater composition and by the negative effects of amoxicillin action. The respirometry assay showed that 1 to 100 ?g L-1 of amoxicillin concentrations did not inhibit the heterotrophic bacteria present in MBR biomass, but concentrations between 1 to 100 mg L-1 inhibit them.
100

Contribution to the development of a dynamic Life Cycle Assessment method / Contribution au développement d’une méthode d’Analyse du Cycle de Vie Dynamique

Shimako, Allan 16 November 2017 (has links)
L'analyse du cycle de vie (ACV) est une méthode très utilisée pour l'évaluation environnementale d'un système anthropique. Les spécialistes ont souligné l'absence de dimension temporelle comme une limitation. Les procédés de la technosphère sont dynamiques, ce qui conduirait à un inventaire de cycle de vie (ICV) dépendant du temps. Les mécanismes environnementaux impliqués dans la génération des impacts ont des caractéristiques dynamiques variées déterminant une manifestation temporelle spécifiques des impacts. Cependant, l’impact du cycle de vie (EICV) actuelles considère des modèles en conditions stationnaires et des horizons de temps arbitrairement fixés. L'objectif de cette thèse est de contribuer au développement d'une méthodologie opérationnelle et des outils adaptés pour la prise en compte du temps dans l'ACV, en accordant une importance au développement d'une approche de modélisation intégrée pour l’ICV et l’EICV. La première contribution de cette thèse concerne le développement d'une base de données temporelle, en s'appuyant sur la base de données ecoinvent, dans laquelle les paramètres temporels ont été attribués aux sets de données. Des indicateurs dynamiques pour le changement climatique et la toxicité ont été développés en adaptant les modèles disponibles et ils ont été mis en place dans un outil de calcul propre. L'approche de modélisation tient compte de la nature fluctuante des émissions des substances en fonction du temps calculées par le modèle d’ICV temporel DyPLCA. / Life Cycle Assessment (LCA) is a widely used method for the environmental evaluation of an anthropogenic system. However, LCA scholars pointed out the lack of a temporal dimension as a limitation. The processes of technosphere are dynamic which leads to a time dependent life cycle inventory (LCI). Environmental mechanisms involved in impact developments have distinct dynamic behaviors determining specific temporal occurrence. However, the current life cycle impact assessment (LCIA) methods consider arbitrarily fixed time horizons and/or steady state conditions. The objective of this thesis is to contribute to the development of an operational methodology and adapted tools for the consideration of time dependency in LCA, with emphasis on the development of an integrated modelling solution for both the life cycle inventory and the life cycle impact assessment phases. The first contribution of this thesis concerns the development of a temporal data base, leaning against ecoinvent data base, in which temporal parameters have been attributed to the data sets. Dynamic climate change and toxicity impacts were developed by adapting available models and were implemented in a homemade computational tool. The modelling approach takes into account the noisy nature of substance emissions in function of time as calculated by DyPLCA temporal LCI model.

Page generated in 0.0394 seconds