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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.
181

Structural and functional diversity of epilithic bacterial communities in streams : effects of pollution

Mahmoud, Huda Mahmoud Abdullah January 2002 (has links)
No description available.
182

Akkumulering van swaarmetale in 'n myn- en nywerheidsbesoedelde meerekosisteem

01 December 2014 (has links)
M.Sc. (Zoology) / Please refer to full text to view abstract
183

Kontaminace nivy Ploučnice těžkými kovy ve vztahu k její architektuře / Contamination of foodplain of the Ploučnice river by heavy metals: relation to its architecture

Hošek, Michal January 2015 (has links)
Summary: This thesis is focused on mapping of contaminants released into the environment probably due to uranium mining. These chemical contaminants are used to reconstruct the sedimentary processes. In the thesis we evaluate geochemical situation in the catchment area in the locality Borecek (part of the municipality Ralsko) using the overbank sediments as sedimentary archives of pollution during the last decades by elements U, Ba, Zn, Ni and 226 Ra. A map of aerial survey of gamma activity was used to select the area of interest, for more accurate localisation we used a surface gamma spectrometry. On Borecek we retrieved ten depth profiles of alluvial sediments (up to 230 cm) and one in Mimon, all samples were subjected to X-ray fluorescence spectral analysis (XRF), across the floodplain we performed gamma wire logs. For interpretations of floodplains architecture electrical resistivity tomography (ERT) was used and selected profiles were analysed for the activity of 226 Ra and 210 Pb. Interrelation of 226 Ra and Ba proved that radiobarite is the main source of the gamma activity. 210 Pb / 226 Ra ratio was used as sediment age indicator. With enrichment factor (LEF), we performed chemostratigraphic correlation of the sediments, for that the concentration of the target elements is corrected for varying...
184

Kontaminace nivy Ploučnice těžkými kovy ve vztahu k její architektuře / Contamination of floodplain of the Ploucnice by heavy metals: relation to its architecture

Hošek, Michal January 2014 (has links)
Summary: This thesis is focused on mapping of contaminants released into the environment probably due to uranium mining. These chemical contaminants are used to reconstruct the sedimentary processes. The aim of the thesis was both the geochemical assessment of the situation in the catchment area of the Ploucnice River in Boreček using the flood sediments from the research points as sedimentary archives pollution for last decades. With depth profiles, gamma wire log, XRF and enrichment factors (LEF), we have tried to perform chemostratigraphic correlation of the sediments. As target elements U, Ba, Zn and Ni were chosen, whose concentrations are related to the grain size of the sediment. Furthermore, the theory of secondary pollution is developed.
185

Die effek van swaarmetale by variërende pH op die bloedfisiologie en metaboliese ensieme van Tilapia sparrmanii (Cichlidae)

19 November 2014 (has links)
M.Sc. / Please refer to full text to view abstract
186

Examining barriers to phytoremediating heavy metal polluted soils in developing countries

Dyer, Mark January 2018 (has links)
Heavy metal soil pollution from anthropogenic sources such as historical use of fertilizers, poor waste disposal, and spills from industries are a serious environmental problem. This can be especially damaging in developing countries where incentives are limited to remediate these soils, and some of the poorest regions are the most affected. Soil remediation can clean heavy metal polluted soil to a level that is sustainable for the environment and the organisms that inhabit it. Many conventional soil remediation techniques can be very expensive, and resource and energy intensive, making them poor choices for developing countries. However, phytoremediation, an emerging soil remediation technology, is much cheaper and less intensive by using the natural ability of certain plants to clean polluted soils. Although phytoremediation has been considered the best available technology for developing countries with heavy metal polluted soil, it is still being underutilized. In this thesis, through the examination of case studies from the U.S., several barriers are identified that are preventing further implementation of phytoremediation projects in developing countries. These barriers include, the difficulties for developing countries in recognising the scale of heavy metal pollution, a lack of enforcement of environmental legislation and standards, prohibitive costs of projects, problems with the effectiveness of phytoremediation as a soil remediation technology, and a lack of technological knowledge. / <p>2018-10-30</p>
187

Interaction Effect of Filler Material on Fungal Biomass Activity for Heavy Metal Biosorption in Stormwater / Interaktionseffekt av Fyllmedelsmaterial på Svampbiomassa för Biosorption av Tungmetaller i Stormvatten

Peterson, Robert January 2018 (has links)
In the wake of ever more occurring and evident consequences brought by climate change such as droughts and an increasing world population, a responsible use and handling of freshwater has never been as important as before. Stormwater is more than often not treated and simply released back in nature with any kind of pollution it has collected on its way, one of which being heavy metals. By treating stormwater not only would this underutilised resource be made use of, creating a new source of freshwater, but environmental pollution caused by untreated stormwater could be potentially decreased, as it can be converted into a potential resource rather than a waste caused by nature. There are a number of already established methods to lower the concentration of heavy metals in water, however there are inherent economical and practical disadvantages with each of them. A method that has shown promising results with potential to challenge these contemporary solutions is biosorption. This study has explored the use of fungal biomass of Rhizopus oryzae for heavy metal biosorption in conjuncture with an organic filler material. The metals investigated were Zn, Cu and Fe. Moreover, the effects of pre-treating the fungal biomass with primarily NaOH were also investigated together with the optimal ratio between biomass and filler material and retention time, in order to maximise biosorption.Pre-treating the fungal biomass with NaOH resulted in a considerable increase in biosorption. Moreover, the presence of the filler material had a positive impact on biosorption by further enhancing it. The best effect was obtained at a 4:1 ratio between biomass and filler material. Finally, the best retention time was determined to be around 2 hours, slowly levelling off at higher retention times. However, the use of pre-treated R. oryzae with filler material did not prove to be efficient regarding the removal of heavy metal ions in stormwater at very low concentration of metals, between approximately 4 to 10 ppb. In the future, it would be worthwhile to investigate the viability of this method on stormwater with higher metal concentrations as well as looking into the effects of pH and temperature. / Som en påföljd av de konsekvenser som klimatförändringen har orsakat, som till exempel svåra torkor tillsammans med en ökande världsbefolkning, har det blivit av allt större vikt att hanteringen av sötvatten sker på ett mer ansvarsfullt och hållbart sätt. Stormvatten brukar inte behandlas överhuvudtaget utan släpps tillbaka i miljön tillsammans med föroreningarna som det samlat på sig under sin väg, bland annat tungmetaller.Det finns redan ett antal metoder för att minska koncentrationen av tungmetaller i vatten, dock inte utan ekonomiska och praktiska svårigheter. Hur som helst så har det forskats en del kring en relativt ny metod som har tidigare visat goda resultat och skulle kunna konkurrera med befintliga lösningar, nämligen biosorption. I denna studie har man utforskat möjligheten att använda svampen Rhizopus oryzae tillsammans med ett organiskt fyllmedelsmaterial för biosorptionen av tungmetaller i stormvatten. De tungmetaller som undersöktes var Zn, Cu och Fe. Dessutom har man undersökt effekterna av ett förbehandlingssteg hos biomassan med NaOH tillsammans med det optimala förhållandet mellan biomassan och fyllemedelsmaterialet och retentionstiden för att maximera biosorptionen. Förbehandlingssteget visade en markant förbättring av biosorptionen. Fyllemedelsmaterialet hade för övrigt också en positiv inverkan genom att ytterligare öka biosorptionen. Ett 4:1 förhållande mellan biomassan och fyllemedelsmaterialet resulterade i det optimala förhållandet för komponenterna med tanke på biosorptionen. För retentionstiden visade det sig de bästa resultaten erhålles vid 2 timmar i lösningen. Emellertid visade det sig att användningen av den förbehandlade svampen tillsammans med fyllemedelsmaterialet inte var effektivt på stormvatten med en väldig låg tungmetallkoncentration, ungefär mellan 4 till 10 ppb. I framtiden skulle det vara intressant att undersöka inte bara metodens genomförbarhet på stormvatten med högre metallkoncentrationer, utan även hur pH-värde samt temperatur kan påverka resultaten.
188

A influência de íons metálicos sobre a biossíntese de exopolissacarídeos e polihidroxibutirato de Rhizobium tropici LBMP-C01 /

Leonel, Tatiane Fernanda. January 2017 (has links)
Orientador: Eliana Gertrudes de Lemos / Coorientador: Cristiane Moretto / Banca: Paulo Inácio da Costa / Banca: João Martins Pizauro Junior / Resumo: Nas últimas décadas, a síntese microbiana de biopolímeros com propriedades biotecnológicas tem atraído atenção crescente. Este trabalho relatou o efeito dos íons metálicos cobre bivalente (Cu2+) e cromo hexavalente (Cr6+) na biossíntese de exopolissacarídeo (EPS) e polihidroxibutirato (PHB), produzidos pela bactéria Rhizobium tropici (LBMP-C01). No ensaio de concentração mínima inibitória (CMI), a rizobactéria apresentou sensibilidade às concentrações superiores a 0,1 mmol L-1 para Cu2+ e 0,05 mmol L-1 para o íon Cr6+. O estudo do efeito destas concentrações de íons metálicos sobre a produção de EPS e PHB, este foi cultivado em meios PSYlíq sem a presença dos íons (controle) e suplementados com os íons separadamente (Cu2+ e Cr6+) e em mistura (Cu2+ + Cr6+). A curva de cultivo mostrou diferenças significativas entre o meio PSYlíq controle e os demais tratamentos contendo os íons metálicos nas concentrações avaliadas. Apesar do efeito dos íons metálicos no cultivo, todos os tratamentos apresentaram células viáveis. Quanto à ação dos íons metálicos sobre a produção de EPS e PHB, foi observado que os tratamentos contendo o íon cromo e os íons em mistura (Cu2+ + Cr6+) reduziram a produção de ambos os biopolímeros. No entanto, o tratamento suplementado com somente o íon Cu2+ induziu o aumento da produção de até 48% de EPS e 46,66% de PHB em relação ao controle, após 144 horas. O estudo de FTIR indicou mínimas diferenças nos grupos funcionais presentes nas moléculas dos biopolímeros... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the last decades, the microbial synthesis of biopolymers with biotechnological properties has attracted increasing attention. This work reported the effect of bivalent copper (Cu2+) and hexavalent chromium (Cr6+) ions on exopolysaccharide biosynthesis (EPS) and polyhydroxybutyrate (PHB), produced by the bacterium Rhizobium tropici (LBMP-C01). In the minimum inhibitory concentration (MIC) test, rhizobacteria showed sensitivity to concentrations higher than 0.1 mmol L-1 for Cu2+ and 0.05 mmol L-1 for the Cr6+ ion. The study of the effect of these metal ion concentrations on EPS and PHB production was carried out in PSYlíq media without the presence of ions (control) and supplemented with ions separately (Cu2+ and Cr6+) and in a mixture (Cu2+ Cr6+). The culture curve showed significant differences between the control PSYlíq medium and the other treatments containing the metal ions at the concentrations evaluated. Despite the effect of metal ions on the culture, all treatments had viable cells. As for the action of the metal ions on the production of EPS and PHB, it was observed that the treatments containing the chromium ion and the ions in the mixture (Cu2+ + Cr6+) reduced the production of both biopolymers. However, the treatment supplemented with Cu2+ alone induced an increase in the production of up to 48% of EPS and 46.66% of PHB in relation to the control after 144 hours. The FTIR study indicated minimal differences in the functional groups present in the molecules of t... (Complete abstract click electronic access below) / Mestre
189

Íons metálicos (Al, Fe, Mn e Pb) associados a aterros (sanitário e industrial) no município de Tremembé/SP / Metals ions (Al, Fe, Mn and Pb) associate to landfills (domestic and industrial) in the city of Tremembé/SP

Moura, Claudia Lucia de 28 November 2008 (has links)
Um dos grandes problemas das Metrópoles tem sido o descarte de resíduos sólidos. Em diversas situações aterros são selecionados como solução de melhor viabilidade para disposição final desses materiais que, na maioria das vezes, são agentes poluentes. Condições inadequadas de operação e conservação desses locais vêm acarretando inúmeros danos ao meio ambiente, em especial, nas áreas de seu entorno que, muitas vezes, possuem aglomerados residenciais. Neste trabalho foram avaliadas condições ambientais mais significativas de uma área e de seu entorno onde se encontram instalados quatro Aterros, três Sanitários e um Industrial, localizados no Município de Tremembé/SP. Provavelmente como conseqüência do mau gerenciamento e descaso das atividades destes Aterros, eles têm sido alvo de inúmeras denúncias, uma vez que trazem grandes prejuízos à população vizinha. Foram estudados os principais agentes poluidores com especial atenção ao comportamento dos íons metálicos alumínio, ferro, manganês e chumbo, em amostras de diferentes compartimentos - solo, solo/sedimento, sedimento de fundo e águas superficiais e subterrâneas. As águas subterrâneas associadas aos Aterros Sanitários encontram-se comprometidas devido a altas concentrações dos íons estudados, cujo comportamento são, em alguns deles, regidos fundamentalmente pelos valores de pH e potencial óxido-redução. Este fato é motivo de grande preocupação, uma vez que na região a grande maioria da população faz uso de águas para consumo humano extraídas de poços do tipo cacimba, além de regas a hortas, dessedentação de animais e abastecimento de ranários por rios e lago. Os dados analíticos das águas superficiais do Rio Serragem e seu afluente que limitam a área de estudo, também apresentaram valores superiores aos permitidos pelos órgãos oficiais para os íons ferro, alumínio e manganês, sempre ligados aos Aterros. Comprovou-se que as características mineralógicas, granulométricas e capacidade de troca catiônica dos solos associados aos Aterros, não são adequadas para a retenção de íons metálicos. Por outro lado os dados de pH do solo (pH) se mostram favoráveis aos fenômenos de adsorção iônica. A geração de chorume é um dos principais passivos ambientais resultados das atividades dos aterros. No âmbito de sugerir idéias que minimizem os impactos produzidos pelo chorume, este trabalho propôs uma destinação mais apropriada para este efluente. Foram realizados experimentos com chorumes dos três Aterros Sanitários estudados e também com chorume coletados no Município de Santo André e Mauá. O trabalho permitiu afirmar que com a eliminação, por aquecimento, da fração líquida do chorume, resulta em um resíduo que tem seu transporte significativamente facilitado devido à redução em mais de 95% de volume, além de apresentar-se rico em potássio, magnésio, cálcio, fósforo, manganês e ferro e cloretos que podem ser reaproveitado na agricultura, em especial no plantio resistente à teores mais elevados de sódio. / A major problem of big cities have been the disposal of solid wastes. In several situations, landfills are selected as solution of better feasibility for final placement of such material that, in most cases, are pollutants. Inadequate conditions of operation and conservation of those locations are giving rise to numerous damage to the environment, in particular, in the surroundings areas that often have residential clusters. In this work have been assessed the most significant environmental conditions in a particular area and its surroundings where were installed four landfills, three sanitaries and one industrial, located in the city of Tremembé / SP. Probably as a result of bad management and careless of these landfills, they have got many complaints, once is bringing on great damage to neighboring population. Were studied the main pollutants with special attention to the behaviour of metal ions, aluminium, iron, manganese and lead on samples of different compartments - soil, sediment / soil, sediment of surface water and groundwater. Groundwater associated with landfill are involved due to high concentrations of the studied ions, which behaviour are, in some of them, essentially governed by the values of pH and oxide-reduction potential. This fact is a reason of great concern, since in the region the vast majority of the population makes use of water, extract from production well, for human consumption, beyond frog farm. The analytics data of the surface water of Serragem River and its stream limits the study field, also submitted values higher than those allowed by official bodies for ions iron, aluminium and manganese, always related to the landfills. It was proved that the mineral characteristics, size analysis and ability to cationic exchange from associated soils with landfills, are not suitable for the retention of metal ions. In the other hand, the data from pH soil ( pH) are favorable to the phenomena of Ionic adsorption strength. The generation of leachate is one of the main environmental liabilities results of the activities of landfills. With the idea to minimize the impact produced by leachate, this work propose a more appropriate destination for this effluent Were carried out experiments with leachate of three studied landfills and also with collected leachate in Santo André and Mauá cities. This work allowed to affirm that with the disposal, by heating the liquid part of the leachate, results in a residue that has its transport significantly facilitated due to the reduction in more than 95% of its volume, and also it performs rich in potassium, calcium, magnesium, phosphorus, iron, manganese and chlorides that can be reused in agriculture, in particular, plantation resistant to higher levels of sodium.
190

Resíduos de mineração e metalurgia: efeitos poluidores em sedimentos e em espécie biomonitora - Rio Ribeira de Iguape - SP / Residues of mining and metallurgy: pollutant effect in sediments and biomonitor organism - River Ribeira de Iguape

Guimarães, Valeria 10 May 2007 (has links)
Por aproximadamente 40 anos, o Rio Ribeira de Iguape recebeu resíduos da mineração: rejeitos das plantas de concentração mineral (enriquecidos em Cu, Cr, Pb, Ag e Zn) e escórias de uma unidade de metalurgia (enriquecidas em Cu, Zn, Cr, Fe, Pb e As), produzidos e descartados pela empresa Plumbum S/A, localizada em Adrianópolis (Paraná). Para verificar a contribuição destes resíduos na contaminação deste rio, como também identificar a possibilidade de depuração natural ou não no mesmo, definiu-se a necessidade de avaliar três compartimentos: resíduos, sedimentos e organismo biomonitor. Nas amostras de resíduos foram realizadas caracterizações físicas e químicas, nos sedimentos foram realizadas análises químicas, granulométricas e algumas amostras investigadas por MEV/EDS e no biomonitor (molusco Asiático da espécie Corbicula fluminea) foram realizadas análises químicas dos tecidos e das carapaças. Estas análises indicaram a existência de elevados teores de Pb nos resíduos da mineração, os quais ultrapassaram os valores deste metal estabelecidos na norma NBR 10.005 da ABNT. Nesta comparação, os rejeitos do concentrado da Mina do Rocha ultrapassaram em 32 vezes, os da Plumbum em 41 vezes e as escórias em 34 vezes, os limites estabelecidos por tal norma, sendo assim classificados como pertencentes à Classe I ? perigosos. Destes resíduos o mais problemático atualmente é o rejeito da Plumbum, por apresentar granulometria fina, pH mais baixo, apresentar maior teor de Pb no teste de lixiviação, além de estar depositado muito próximo de uma das margens do Rio Ribeira de Iguape. A interação destes resíduos com o sistema aquático foi verificada a partir da detecção de Pb, Zn, Cu nos sedimentos. Os sedimentos depositados em bancos de areia e os estuarinos exibiram maiores teores para Pb (média de 135,00 mg/kg para os depósitos em bancos de areia e 124,00 mg/kg para os estuarinos) e Zn (média de 112,62 mg/kg para os depositados em bancos de areia e de 133,00 mg/kg para os estuarinos). Em todos os tipos de sedimentos foi constatado que o local de coleta que exibiu teores mais elevados para os metais de estudo foi em Iporanga, secundariamente na Ilha do Caranguejo na região do Mar Pequeno, a sul de Iguape. Nos sedimentos em suspensão, as análises em MEV/EDS exibiram a presença de grãos de escória, indicando que estes ainda hoje, estão interagindo com este ambiente e sendo transportados. Esta comprovação, só foi possível, de fato, a partir das análises de tecidos e de carapaças da espécie Corbicula fluminea, os quais demonstraram estar havendo interação dos metais pesados provenientes dos resíduos com a biota deste sistema aquático. Nos tecidos deste biomonitor foram detectados em média 23,99 ?g/g de Cu, 144,21 ?g/g de Zn, 0,71 ?g/g de Cd, 2,41 ?g/g de Pb e 7,11 ?g/g de Cr. Destes metais, o mais preocupante é o Pb, ele apresenta concentrações mais elevadas que os relatados em outros estudos para este mesmo bivalve e também, ultrapassa o valor de referência da ANVISA (2,00 ?g/g) para a concentração deste metal pesado em peixes e produtos de pesca para consumo. Além dos tecidos, as carapaças deste biomonitor, também estão concentrado estes metais pesados. De modo geral, concluiu-se que o Rio Ribeira não está sofrendo processos naturais de depuração e que ainda hoje representa um problema ambiental, pois os metais estão migrando ao longo do curso da drenagem e neste processo sendo biodisponibilizados, o que pode vir a gerar transferência e acumulação na cadeia trófica. / For approximately 40 years, Ribeira de Iguape River received mining wastes (enriched in Cu, Cr, Pb, Ag and Zn) and metallurgical slags (enriched in Cu, Zn, Cr, Fe, Pb and As), produced and discharged by Plumbum S/A, a company located in Adrianópolis (Paraná). In order to verify the contribution of these residues in the river contamination and natural purification the compartments of mining residues, sediments and bioindicator organisms were evaluated. Physical and chemical characterizations were realized in the residues samples; while chemical analyses, grain size evaluation and MEV/EDS were carried out in sediments. Asiatic clam (Corbicula fluminea) was taken as a bioindicator, through chemical analyses of its tissues and shells. The results showed high Pb levels, being classified as Class 1 ? dangerous - by ABNT, norm NBR 10,005, once the limited levels were exceeded by Rocha wastes (32x), Plumbum wastes (41x) and slags (34x). The Plumbum waste is currently the most problematic, as it is made of fine grain, lower pH, higher Pb level detected in the extraction test and is deposited very close to the draining site. The interactions of these residues with the aquatic system was verified through Pb, Zn, Cu detection in the sediments. Pb and Zn levels were, respectively, 135.00 mg/kg and 112.62 mg/kg in the sand banks deposits, and 124.00 mg/kg and 133.00 mg/kg in the estuaries deposits, with prominent metal levels in Iporanga and, secondary, in Crab Island, region of the Small Sea, south of Iguape. MEV/EDS analyses carried out in suspended sediments showed the presence of slags grains, suggesting that still nowadays they are transported and interact with the environment, once they have been detected in tissues and shells samples of Corbicula fluminea. In the tissues of this bioindicator, there were detected average levels of 23.99 ?g/g of Cu, 144.21 ?g/g of Zn, 0.71 ?g/g of Cd, 7.11 ?g/g of Cr and 2.41 ?g/g of Pb; making evident that this last value is strongly high and over the ANVISA reference (2.00 ?g/g) for fish and other consumption products. The results suggest that natural processes of Ribeira de Iguape River are not sufficient for its purification, keeping metals\' transport and bioavailability, which can accumulate in the trophic chain, representing a serious environmental problem.

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