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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.
441

Pesticide use in rice cultivation in Tarapoto, Peru : usage patterns and pesticide residues in water sources /

Palm, Britta, January 2007 (has links) (PDF)
Examensarbete.
442

The relation between spectral reflectance and dissolved organic carbon in lake water ; Kejimkujik National Park, Nova Scotia /

Hirtle, Heather D. M. January 1900 (has links)
Thesis (M.A.)--Carleton University, 2001. / Includes bibliographical references (p. 90-95). Also available in electronic format on the Internet.
443

Bacterial community composition, TCE degradation, isotopic fractionation and toxicity of a TCE contaminated aquifer

Brown, Jillian. January 2009 (has links)
Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on Oct. 7, 2009). Includes bibliographical references.
444

Toxicological Comparison of Heavy Metal Salt and Semiconductor Nanoparticle Exposure in Zebrafish (Danio rerio)

Johnson, Adam Nicholas January 2007 (has links) (PDF)
No description available.
445

Determination of physiochemical properties and metal levels in soil, water, and plant from Alice landfill site

Maphuhla, N G January 2017 (has links)
The state of soil is of great significance because it is a common medium for plant growth, which provides important nutrients to plants. Water pollution is the build-up of harmful substances in water bodies to the level that results in health problems for people and animals. Heavy metal pollution (of soil, water, and plants) and their health effects on people is a persistent social issue, and several types of research have recognized health risks of residents living close to open dumpsites. Dump sites are sources of heavy metal impurity and toxicity to the surrounding environment. Analyses were done on water and soil samples for temperature, pH, Electrical conductivity (EC), Total dissolved solids (TDS), alkalinity, organic matter, organic carbon and total hardness. The pH results range from slightly acidic (6.79) to neutral soil pH (7.09), and have been recorded within the normal range from WHO. All the determined physicochemical properties in soil and water have been recorded within the normal range, except for EC in water which was found to be above the permissible limits by WHO. The heavy metals concentration was determined using the AAS technique. The results obtained shows that the dumpsite‘s soil consists of high metal concentration when compared to control site. The concentration in dumpsites ranges between 1.2783 ± 0.83 mg/kg to 26.3213 ± 6.37 mg/kg. The descending order for selected metal concentrations were in this following order Mn> Cu>Hg>Pb. The Pb and Hg mean concentration was recorded above permissible limits, while the Mn and Cu were within the normal range suggested by WHO. In both water and Acacia karroo samples the Cu was not detected. The trend of metal concentration in water sample was found to be in this order Hg> Mn > Pb> Cu, while in Acacia karroo metal concentration is Hg> Mn> Pb> Cu. The one-way ANOVA test was used to compare the mean concentration of selected metals in each sampling site. The results show that there is a statistically significant difference between the mean concentrations of selected metals; this is supported by the value of F-static and p-value (p <0.05)
446

Monitoramento de água superficial densamente poluída - O córrego Pirajussara, Região Metropolitana de Sao Paulo, Brasil / The monitoring process of the surface water with dense pollution the Pirajuçara stream, metropolitan area of São Paulo, Brazil

GODOI, EVELYN L. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:54:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:58Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
447

Investigação da biomassa de Eichhornia crassipes (aguapé) para a obtenção de etanol de segunda geração como um processo mitigatório da poluição aquática /

Bronzato, Giovana Roberta Francisco, 1990. January 2016 (has links)
Orientador: Alcides Lopes Leão / Coorientador: Ivana Cesarino / Banca: Claudio Angeli Sansigolo / Banca: Rubens Maciel Filho / Resumo: A Eichhornia crassipes, conhecida popularmente como aguapé, é uma macrófita aquática nativa no Brasil que tem um grande poder de adaptação e uma taxa de crescimento muito elevada, chegando a cobrir o leito de um rio em poucas semanas. Por esses motivos, atualmente, esse vegetal é considerado uma praga, pois sua grande quantidade causa danos ambientais a corpos hídricos, como a eutrofização desses habitats e no setor econômico prejudica a navegação e a produção de energia, pois se prendem aos motores e as turbinas, respectivamente. Uma alternativa para resolver o problema do excesso de aguapé é utilizar a sua biomassa para a produção de etanol de segunda geração, uma tecnologia que utiliza a celulose dos vegetais como matéria-prima. Nesta dissertação foram estudadas algumas rotas de produção, com a intenção de encontrar uma metodologia eficiente para a produção de etanol 2G a partir do aguapé. Para isso foram utilizados quatro diferentes processos químicos de pré-tratamento, auto-hidrólise, hidrólise com peróxido de hidrogênio, e hidrólise com os ácidos sulfúrico e acético, e duas formas de hidrólise enzimática, simultânea ou separada do processo de fermentação alcoólica. Pela caracterização química e pelas análises de TG-DTA, XRD e FTIR, foi possível determinar que a hidrólise com ácido sulfúrico é o pré-tratamento mais eficiente e que os processos de hidrólise enzimática e fermentação alcoólica simultâneas apresentam uma maior produtividade. Em um ano, com apenas um hectare,... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Water hyacinth, Eichhornia crassipes, is a native macrophyte from Brazil that has a great ability to adapt and a very high growth rate, reaching to cover the riverbed in a few weeks. For these reasons, currently, water hyacinth is considered a pest because its large amount causes environmental damage to the rivers and lakes, such as eutrophication of these habitats, and economic sector, affecting navigation and energy production because they are arrested to engines and turbines respectively. An alternative to resolve the excess water hyacinth problem is to use its biomass to second generation ethanol production, which technology use cellulose like feedstock. In this work were studied some ways to optimize the production of 2G ethanol from water hyacinth. For this were used different chemical pre-treatment processes (hydrolysis with water, peroxide, sulfuric and acetic acids), and two way to enzymatic hydrolysis (SSF and SHF). Through the chemical characterization and TG-DTA, XRD and FTIR analyses, was possible to determine that sulfuric acid hydrolysis is the pretreatment more effective and that SSF has the bigger productivity. In one year, from one hectare covered by water hyacinth, it's possible to produce 265 liters of ethanol. / Mestre
448

Oxidative stress responses in the aquatic macrophyte, Ceratophyllum Demersum L., as biomarkers of metal exposure

Arnolds, Judith Lize January 2017 (has links)
Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2017. / Metal pollution in aquatic environments is considered a major environmental concern because of variation in several abiotic factors that impose severe restrictions on organisms living in these areas. Ceratophyllum demersum L. (family Ceratophyllaceae), a hornwort or coontail, free floating rootless macrophyte has been suggested a suitable model for investigating metal stress and was used in the current study. This study assessed the use of selected biological responses, namely antioxidant responses and changes in chlorophyll concentration in Ceratophyllum demersum L., as biomarkers of metal exposure, and also investigated the field application of these responses in the Diep River. The ultimate aim was also to determine the usefulness of C. demersum as model of metal contamination and as phytoremediator after a pollution event. An investigation of metal bioaccumulation in this macrophyte exposed to different concentrations of a combination of metals over a five-week exposure period in a greenhouse, was undertaken, as well as a field study in the Diep River, Milnerton, Cape Town and a pond (reference site) at the Cape Peninsula University of Technology, Cape Town, to validate experimental results. In the laboratory study the water was contaminated once off at the beginning of the study, to simulate a pollution event. The metal concentrations in the water and plants were measured in the four treatments and the control every week over a five-week exposure period. The samples were acid-digested and analysed with an Inductively-Coupled Plasma-Mass Spectrophotometer (ICP-MS). The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns amongst the treatment groups. This macrophyte proved highly effective in the bioaccumulation of these metals at all four exposure concentrations. The metals bioaccumulated rapidly in the plants after the water was spiked. The main focus of the study was to investigate the possible use of biochemical responses in C. demersum as possible biomarkers for metal exposure. A range of antioxidant/oxidative stress parameters were measured in the plant exposed to a combination of metals (Al, Cu, Fe, Zn) in four different treatments over the five week exposure period. Total antioxidant capacity (TAC) was measured using Total Polyphenols (TP), Ferric Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity assay (ORAC), enzyme activity was determined using Catalase (CAT), Superoxide Dismutase (SOD), Ascorbate Acid (AsA) and Total Glutathione (GSHt) and lipid peroxidation was measured by using Thiobarbituric Acid Reactive Substances (TBARS) and Conjugated Dienes (CDs). The cocktail of the four metals induced significant changes in the antioxidant defence system of C. demersum, including the antioxidant enzyme activities. The different metal exposures disturbed the cellular redox status in the plant. The current study has demonstrated that this macrophyte shows tolerance to metal-induced oxidative stress and that it can survive under relatively high concentrations of these metals by adapting its antioxidant defence strategies. Chlorophyll was extracted in 80% chilled acetone in the dark and the absorbance values were determined using a spectrophotometer. Chlorophyll a (chl a), chlorophyll b (chl b) and total chlorophyll (chl t) contents were measured under different exposure concentrations of metals in the macrophyte. The results of this study indicated that chlorophyll contents were variable over the exposure period and no significant differences in chlorophyll concentrations were found between weeks. A field study in the Diep River and the pond located at the CPUT campus (reference site) was conducted to validate experimental results. Plants in a polluted section of the Diep River were shown to bioaccumulate metals to high concentrations. Bioaccumulation of metals in C. demersum might have induced oxidative stress, and other environmental factors such as temperature- and chemical stress might have caused chlorophyll degradation. The chlorophyll concentrations in the plants of the pond (reference site) might also have been affected by temperature and chemical stress of the water. Significantly higher AsA, CAT, ORAC, SOD and TBARS concentrations in the Diep River plants might be an indication that the plants in the river might be well adapted to the constant exposure to metals and that the plants might have developed a tolerance mechanism to cope with oxidative stress compared to those of the pond. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the "pollution event". However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time. This study has shown that C. demersum has phytoremediation potential because it was able to remove high concentrations of metals from the contaminated water. Therefore, C. demersum, can be applied as a model for metal contamination and a phytoremediator after a pollution event. The potential to antioxidant responses and chlorophyll content as biomarkers of metal exposure in C. demersum have been demonstrated.
449

Avaliação da presença de chumbo (Pb) em espécies de peixes associada à qualidade ambiental da Bacia do Ribeirão Cambé (Londrina/PR)

Torrezani, Nelissa Camargo 24 April 2015 (has links)
CAPES / O chumbo é um elemento não-essencial, bioacumulador, com propriedades altamente tóxicas e responsável por efeitos agudos e crônicos nos seres vivos. Em concentrações elevadas podem promover danos às comunidades aquáticas, modificando suas estrutura e distribuição. O presente estudo verificou o grau de vulnerabilidade ambiental da Bacia do Ribeirão Cambé, a partir da avaliação da presença de chumbo nas espécies de peixes mais abundantes, por meio da técnica analítica de Espectrometria de Absorção Atômica com Atomizador em Forno de Grafite (GF AAS), assim como, pelos parâmetros da estrutura da assembléia de peixes que envolveram as análises de riqueza, equitabilidade, diversidade, abundância, biomassa e comprimento padrão das espécies. Além desses parâmetros, também foram analisadas variáveis físicas e químicas da água utilizando equipamentos portáteis (temperatura da água, pH, condutividade elétrica, turbidez e oxigênio dissolvido), e por último, a análise dos padrões de uso e ocupação do solo, obtidos por meio da literatura. Os resultados revelaram ampla área impermeabilizada ao longo do gradiente longitudinal do Ribeirão Cambé e trechos de agricultura/campo, sendo essa última classe mais dominante no ponto de amostragem 6. Os parâmetros abióticos avaliados estiveram dentro do limite permitido pela Resolução CONAMA 357/2005, exceto o oxigênio dissolvido que revelou concentrações inferiores a 6 mg.L-1 nos pontos de amostragem 3 e 4, os quais compreendem o Lago Igapó, corpo aquático enquadrado na Classe I. Além disso, a condutividade elétrica foi elevada para todos os pontos, quando comparados aos valores estabelecidos pela Companhia de Tecnologia de Saneamento Ambiental (CETESB). Em relação à composição da ictiofauna, verificou-se a presença de três espécies exóticas: Poecilia reticulata, Oreochromis niloticus e Tilapia rendalli, distribuídas com abundância na maioria dos pontos de amostragem. A espécie nativa Hypostomus ancistroides também esteve presente na maioria dos pontos do Ribeirão Cambé, evidenciando tolerância a ambientes poluídos, semelhantemente às espécies exóticas. Os pontos 2 e 5 foram os que apresentaram maior equitabilidade e diversidade. A Poecilia reticulata revelou maior abundância para todos os pontos de amostragem, enquanto a biomassa foi destaque para quatro espécies: Geophagus brasiliensis, Oreochromis niloticus, Hypostomus ancistroides e Hypostomus regani. Quanto ao comprimento padrão das espécies, a classe dos pequenos foi a mais representativa. Referente às concentrações de chumbo nas espécies de peixes, as médias no verão variaram de 0,18 a 6,74 mg.kg-1, apresentando diferenças significativas e acima do limite permitido para os pontos 1, 2, 3, 4 e 5. No outono, as concentrações médias de chumbo variaram de 0,04 a 0,17 mg.kg-1 entre os pontos e abaixo do limite permitido, enquanto no inverno as médias variaram de 0,04 a 4,83 mg.kg-1, apresentando diferenças significativas e acima do limite permitido para os pontos 2, 3 e 5. A partir desses dados, a Análise de Correlação Canônica confirmou que os pontos 1, 4 e 5 estavam afetados pela presença de chumbo, enquanto o ponto 6 se mostrou mais rico em oxigênio, além de maior biomassa e o ponto 2 evidenciou boa oxigenação e espécies de maior porte. / Lead is a non-essential element, bioaccumulative, with highly toxic properties and is responsible for acute and chronic effects on living beings. In high concentrations may promote damage to aquatic communities by modifying their structure and distribution. This study found the degree of environmental vulnerability of the Cambé Stream Basin, from the evaluation of the presence of lead in the most abundant species of fish, through the analytical technique of Graphite Furnace Atomic Absorption Spectrometry (GF AAS), as well as the parameters of the fish assemblage structure involving wealth, equitability, diversity, abundance, biomass and standard length analysis of species, beyond the physical and chemical variables of water from portable equipment, and finally, the analysis of patterns of use and occupation of land obtained through literature. The results revealed wide impermeabilized area along the longitudinal gradient of Cambé Stream Basin and agriculture/field, the latter being most dominant class in the sampling point 6. The evaluated abiotic parameters (water temperature, pH, conductivity, turbidity and dissolved oxygen) were within the limit allowed by CONAMA Resolution 357/2005, except the dissolved oxygen showed concentrations below 6 mg L-1 in the sampling points 3 and 4, which comprise the Igapó Lake, water body framed in Class I. In addition, the electrical conductivity was high for all points when compared to the values established by the Environmental Sanitation Technology Company (CETESB). Regarding the composition of fishes verified the presence of three exotic species: Poecilia reticulata, Oreochromis niloticus and Tilapia rendalli, in most heavily distributed sampling points. The Hypostomus ancistroides kind of native character also present in most parts of Cambé Stream, showing tolerance to polluted environments, similar to exotic species found. Points 2 and 5 were those with the highest evenness and diversity. Poecilia reticulata showed greater abundance for all sampling points and the biomass obtained emphasis on four species: Geophagus brasiliensis, Oreochromis niloticus, Hypostomus ancistroides and Hypostomus regani. As for the standard length of the small species was the most representative. Regarding lead concentrations in fish species, the means in the summer ranged from 0.18 to 6.74 mg.kg-1, showing significant differences and above the limit allowed for the points 1, 2, 3, 4, and 5. In the autumn, the means concentrations of lead ranged from 0.04 to 0.17 mg.kg-1, between points, with no statistical difference and below the limit allowed, and in winter, the means ranged from 0.04 to 4.83 mg.kg-1, among the points, showing significant differences and above the limit allowed for the points 2, 3 and 5. Thus, from the Canonical Correlation Analysis confirmed that the points 1, 4 and 5 are affected by the presence of lead. Point 6 was more rich in oxygen, and the largest biomass and point 2 showed good oxygenation and larger species.
450

Avaliação da presença de chumbo (Pb) em espécies de peixes associada à qualidade ambiental da Bacia do Ribeirão Cambé (Londrina/PR)

Torrezani, Nelissa Camargo 24 April 2015 (has links)
CAPES / O chumbo é um elemento não-essencial, bioacumulador, com propriedades altamente tóxicas e responsável por efeitos agudos e crônicos nos seres vivos. Em concentrações elevadas podem promover danos às comunidades aquáticas, modificando suas estrutura e distribuição. O presente estudo verificou o grau de vulnerabilidade ambiental da Bacia do Ribeirão Cambé, a partir da avaliação da presença de chumbo nas espécies de peixes mais abundantes, por meio da técnica analítica de Espectrometria de Absorção Atômica com Atomizador em Forno de Grafite (GF AAS), assim como, pelos parâmetros da estrutura da assembléia de peixes que envolveram as análises de riqueza, equitabilidade, diversidade, abundância, biomassa e comprimento padrão das espécies. Além desses parâmetros, também foram analisadas variáveis físicas e químicas da água utilizando equipamentos portáteis (temperatura da água, pH, condutividade elétrica, turbidez e oxigênio dissolvido), e por último, a análise dos padrões de uso e ocupação do solo, obtidos por meio da literatura. Os resultados revelaram ampla área impermeabilizada ao longo do gradiente longitudinal do Ribeirão Cambé e trechos de agricultura/campo, sendo essa última classe mais dominante no ponto de amostragem 6. Os parâmetros abióticos avaliados estiveram dentro do limite permitido pela Resolução CONAMA 357/2005, exceto o oxigênio dissolvido que revelou concentrações inferiores a 6 mg.L-1 nos pontos de amostragem 3 e 4, os quais compreendem o Lago Igapó, corpo aquático enquadrado na Classe I. Além disso, a condutividade elétrica foi elevada para todos os pontos, quando comparados aos valores estabelecidos pela Companhia de Tecnologia de Saneamento Ambiental (CETESB). Em relação à composição da ictiofauna, verificou-se a presença de três espécies exóticas: Poecilia reticulata, Oreochromis niloticus e Tilapia rendalli, distribuídas com abundância na maioria dos pontos de amostragem. A espécie nativa Hypostomus ancistroides também esteve presente na maioria dos pontos do Ribeirão Cambé, evidenciando tolerância a ambientes poluídos, semelhantemente às espécies exóticas. Os pontos 2 e 5 foram os que apresentaram maior equitabilidade e diversidade. A Poecilia reticulata revelou maior abundância para todos os pontos de amostragem, enquanto a biomassa foi destaque para quatro espécies: Geophagus brasiliensis, Oreochromis niloticus, Hypostomus ancistroides e Hypostomus regani. Quanto ao comprimento padrão das espécies, a classe dos pequenos foi a mais representativa. Referente às concentrações de chumbo nas espécies de peixes, as médias no verão variaram de 0,18 a 6,74 mg.kg-1, apresentando diferenças significativas e acima do limite permitido para os pontos 1, 2, 3, 4 e 5. No outono, as concentrações médias de chumbo variaram de 0,04 a 0,17 mg.kg-1 entre os pontos e abaixo do limite permitido, enquanto no inverno as médias variaram de 0,04 a 4,83 mg.kg-1, apresentando diferenças significativas e acima do limite permitido para os pontos 2, 3 e 5. A partir desses dados, a Análise de Correlação Canônica confirmou que os pontos 1, 4 e 5 estavam afetados pela presença de chumbo, enquanto o ponto 6 se mostrou mais rico em oxigênio, além de maior biomassa e o ponto 2 evidenciou boa oxigenação e espécies de maior porte. / Lead is a non-essential element, bioaccumulative, with highly toxic properties and is responsible for acute and chronic effects on living beings. In high concentrations may promote damage to aquatic communities by modifying their structure and distribution. This study found the degree of environmental vulnerability of the Cambé Stream Basin, from the evaluation of the presence of lead in the most abundant species of fish, through the analytical technique of Graphite Furnace Atomic Absorption Spectrometry (GF AAS), as well as the parameters of the fish assemblage structure involving wealth, equitability, diversity, abundance, biomass and standard length analysis of species, beyond the physical and chemical variables of water from portable equipment, and finally, the analysis of patterns of use and occupation of land obtained through literature. The results revealed wide impermeabilized area along the longitudinal gradient of Cambé Stream Basin and agriculture/field, the latter being most dominant class in the sampling point 6. The evaluated abiotic parameters (water temperature, pH, conductivity, turbidity and dissolved oxygen) were within the limit allowed by CONAMA Resolution 357/2005, except the dissolved oxygen showed concentrations below 6 mg L-1 in the sampling points 3 and 4, which comprise the Igapó Lake, water body framed in Class I. In addition, the electrical conductivity was high for all points when compared to the values established by the Environmental Sanitation Technology Company (CETESB). Regarding the composition of fishes verified the presence of three exotic species: Poecilia reticulata, Oreochromis niloticus and Tilapia rendalli, in most heavily distributed sampling points. The Hypostomus ancistroides kind of native character also present in most parts of Cambé Stream, showing tolerance to polluted environments, similar to exotic species found. Points 2 and 5 were those with the highest evenness and diversity. Poecilia reticulata showed greater abundance for all sampling points and the biomass obtained emphasis on four species: Geophagus brasiliensis, Oreochromis niloticus, Hypostomus ancistroides and Hypostomus regani. As for the standard length of the small species was the most representative. Regarding lead concentrations in fish species, the means in the summer ranged from 0.18 to 6.74 mg.kg-1, showing significant differences and above the limit allowed for the points 1, 2, 3, 4, and 5. In the autumn, the means concentrations of lead ranged from 0.04 to 0.17 mg.kg-1, between points, with no statistical difference and below the limit allowed, and in winter, the means ranged from 0.04 to 4.83 mg.kg-1, among the points, showing significant differences and above the limit allowed for the points 2, 3 and 5. Thus, from the Canonical Correlation Analysis confirmed that the points 1, 4 and 5 are affected by the presence of lead. Point 6 was more rich in oxygen, and the largest biomass and point 2 showed good oxygenation and larger species.

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