• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • Tagged with
  • 5
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 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.
1

Chemismus vody a sedimentů fluviálních jezer Labe / Water and sediment chemistry of fluvial lakes of the Elbe River

Chalupová, Dagmar January 2011 (has links)
The presented paper aims at the problems of fluvial lakes in middle course of the Elbe River which has been influenced by the human activity since the Middle Ages. The oxbow lakes which are extremely precious ecosystems contributing to the stability of the river ecosystem show not only the changes of the course of the Elbe River. With regard to sedimenting a great amount of pollutants, these lakes also tell about the industrial pollution to which the river was exposed mainly in the second half of the 20th century due to insufficient precautions on industrial sources causing contamination. 5 cut lakes between Hradec Králové and Mělník have been studied within this research. These lakes differ in the intensity of communication with the river, in the distance from significant sources of industrial pollution and in the use of nearby land. The research included morphometric and bathymetric measures, observation of hydrological regime, seasonal measures in the water column and regular analysis of surface water samples. Profiles of sediments in the length that the used technology allowed were sampled, so that older anthropogenic load could be found out. The amount of organic carbon and concentration of selected metal and arsenic (Ag, Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) were stated apart from grain size...
2

ASPECTOS QUÍMICO-BIOLÓGICOS DA ÁGUA DA LAGOA ALEXANDRINO CÂNDIDO GOMES, PORANGATU- GO NO PERÍODO DE FEVEREIRO 2014 A AGOSTO DE 2016 / Chemical-biological aspects of pond water Alexandrian Cândido Gomes, Porangatu-GO from february 2014 to august 2016

Pacheco, Sueli Maria Moraes 18 August 2016 (has links)
Submitted by admin tede (tede@pucgoias.edu.br) on 2016-11-30T17:54:39Z No. of bitstreams: 1 SUELI MARIA MORAES PACHECO.pdf: 2123797 bytes, checksum: 92fcd55716c6c6c68c13ed7190d1696c (MD5) / Made available in DSpace on 2016-11-30T17:54:39Z (GMT). No. of bitstreams: 1 SUELI MARIA MORAES PACHECO.pdf: 2123797 bytes, checksum: 92fcd55716c6c6c68c13ed7190d1696c (MD5) Previous issue date: 2016-08-18 / The quality of surface water in urban collections suffer chronically with the influence of the environment in their surroundings, accumulating solid waste, industrial, commercial and domestic pollutants. This study aims to produce a diagnosis of the quality of the pond water Alexandrian Cândido Gomes from the analysis of physical-chemical parameters and biological surface water, located in the city of Porangatu / GO, covering 2400 m² of waterfront with a liquid surface average of 2 square kilometers in the urban area and consists of approximately 6 square kilometers in area of contribution. Samples were collected for a period of two years between the months of March 2015 to April 2016 in six selected points, two collections for each point. Samples were analyzed for determination of the parameters pH, temperature, concentration of ions (arsenic, cadmium, lead, chromium, mercury), and the term tolerant coliforms. The mercury and arsenic ions were not detected during the study, pH and temperature maintained an average of 7.3 and 29.8 ° C respectively. Some samples presented significant amounts of toxic metals and fecal coliforms. Cadmium in one of the sites was higher than recommended by current legislation in the dry season in 2015. The lead, in the dry season showed a value above the recommended for one of the points, as well as chromium. The test fecal coliforms showed good water quality in most of the plumbed period, despite being above the permitted at one point in the rainy season in 2015. It highlighted the role of government and private the need to strategize and review existing, seeking to improve the site, promoting the constant monitoring the areas most vulnerable to pollution detected in the environment and revitalizing the waterfront and health vegetation, giving security to users who attend, as a recreational area and resort this scenic city landmark and its residents the confidence of well-being in relation to health. / A qualidade da água superficial em coleções urbanas sofre cronicamente com a influência do ambiente em seus arredores, acumulando resíduos sólidos, poluentes industriais, comerciais e domésticos. Este estudo tem como objetivo produzir um diagnóstico da qualidade da água da Lagoa Alexandrino Cândido Gomes a partir da análise de parâmetros físico-químicos e biológicos da água superficial, situada no município de Porangatu/GO, abrangendo 2400 m² de orla, com uma superfície liquida média de 2 km² na mancha urbana e constituída aproximadamente de 6 km² em área de contribuição. Foram coletadas amostras por um período de dois anos entre os meses de março 2015 a abril de 2016 em seis pontos selecionados, sendo duas coletas para cada ponto. As amostras foram analisadas para a determinação dos parâmetros do pH, temperatura, concentração de íons (arsênio, cádmio, chumbo, cromo, mercúrio) e coliformes termo tolerantes. Os íons arsênio e mercúrio não foram detectados durante o estudo, o pH e temperatura mantiveram uma média de 7,3 e 29,8 °C respectivamente. Algumas amostras coletadas apresentaram valores significativos de metais tóxicos e coliformes termotolerantes. O cádmio em um dos pontos avaliados ficou acima do recomendado pela legislação vigente no período de estiagem em 2015. O chumbo, no período de estiagem apresentou valor acima do recomendado para um dos pontos, bem como o cromo. O ensaio de coliformes termotolerantes demonstrou a boa qualidade da água na maior parte do período sondado, apesar de ficar acima do permitido em um ponto no período chuvoso em 2015. Fica evidenciado o papel do poder público e privado a necessidade de se criar estratégias e rever as já existentes, buscando melhorar o local, promovendo o monitoramento constante as áreas mais vulneráveis a poluição detectada no ambiente e na revitalização da vegetação marginal e sanitária, dando segurança aos usuários que a frequentam, como área de lazer e balneário este marco paisagístico da cidade e aos seus moradores a confiança do bem estar em relação à saúde.
3

ANÁLISE DOS PARÂMETROS FÍSICO-QUÍMICOS E METAIS PRESENTES NAS NASCENTES DO RIO MEIA PONTE.

Barbosa, Igor Silva 25 February 2015 (has links)
Made available in DSpace on 2016-08-10T10:44:44Z (GMT). No. of bitstreams: 1 IGOR SILVA BARBOSA.pdf: 2324780 bytes, checksum: 404e6b1a1c1a079e20a17f4884a14470 (MD5) Previous issue date: 2015-02-25 / In this dissertation was determined variations in physicochemical parameters and metal pollutants in water collected in the springhead of the Meia Ponte river Goiás, samples were collected from 20 points downstream and upstream and the data were statistically treated. The physicochemical parameters evaluated were pH, conductivity, dissolved oxygen, temperature and luminosity. The pH and luminosity showed in accord with by law. With respect to conductivity and dissolved oxygen were observed variations when compared to CONAMA 357-2005 standards, the conductivity parameter in the collection point 17 in both in the downstream as well as in the upstream the indexes was too high, it can be justified because of the production of ruminants next to the collection points and also to the have high ground slope, facilitating the flow of wastes from the production to the riverbed. For OD parameter were observed anomalies in points 10,11,12,13,14,15 and 19, those increases are justified because by factors such as: anthropic actions and flood plains in the collection locations. For metals pollutants were observed in all the samples, that Cu and Cr are in accord to the standards set out by law for drinking waters, Cd and Pb showed high values only in point 1 which can mainly due to antropic action, already Zn showed a high value only in point 3, Mn on the other hand was the metal that was above the standard in highest number of points, alterations can be observed in the points 1,2,9,10,11,13,15,16,18, and 20, this was probably due to the geological characteristics of the region which the samples were collected. / Nessa dissertação foi determinada as variações de parâmetros físico-químicos e metais poluentes em água nas nascentes do rio meia ponte em Goiás, onde foram coletadas amostras de 20 pontos a jusante e montante e os dados foram tratados estatisticamente. No Parâmetro físico-químico foi avaliado pH, condutividade, Oxigênio Dissolvido, Temperatura e Luminosidade. Os parâmetros pH e luminosidade encontraram-se dentro da normalidade estabelecida pela legislação. Em relação a Condutividade e Oxigênio Dissolvido ocorreram variações significativas de acordo com os padrões do CONAMA 357-2005. No parâmetro condutividade no ponto de coleta 17 na jusante assim como na montante, os índices ficaram bem elevados e são justificados devido a produção de ruminantes próxima aos pontos de coletas e também ao terreno ter alto declive, facilitando o escoamento de resíduos da produção para o leito do rio. Em relação ao parâmetro OD, foi observada anomalias nos pontos 10,11,12,13,14,15 e 19, são justificados esses aumentos devido a alguns fatores como: ações antrópicas e áreas de várzeas nos locais de coleta. Para os metais poluentes, foi observado em todas as amostras, que o Cu e Cr estão dentro dos padrões estabelecidos pela legislação para águas potáveis, Cd e Pb apresentaram valores elevados apenas em uma mostra coletada no ponto 1,que pode ser devida principalmente a ação antrópica, já o Zn apresentou valor elevado apenas no ponto 3, o Mn por sua vez foi o metal que esteve acima dos padrões em maior número de pontos podendo ser observadas alterações nos pontos, 1,2,9,10,11,13,15,16,18 e 20, isso provavelmente deve-se às características geológicas da região onde as amostras foram coletadas.
4

Uptake and mobilisation of metals associated with estuarine intertidal sediment by microphytobenthic diatoms

Becker, Amani Eve January 2017 (has links)
Microphytobenthos (MPB), a mixed community of microscopic, photosynthetic organisms, algae and cyanobacteria, inhabiting the top few millimetres of bottom sediment, is a key component of intertidal mudflats. It accounts for a significant proportion of estuarine primary production, forms the base of the food chain and influences sediment distribution and resuspension (through production of extracellular polymeric substances (EPS)). Diatoms dominate the microphytobenthos community in the mid-latitudes of the Northern Hemisphere. Estuarine sediments, are a sink for metal contaminants derived from fluvial, marine and atmospheric sources. Whilst metal releases to estuaries have declined in recent years due to increased regulation and declining industrial activity, metals previously discharged and which are now locked up in saltmarsh sediments remain a concern. For example, there are indications that saltmarshes are already being eroded, due to climate change related sea level rise, in some locations. This erosion may result in the redistribution of historically contaminated sediment to locations, such as the mudflats, where it is more available to biota, such as the MPB. In addition to causing redistribution, climate change effects, such as increasing temperatures and storminess, may also alter the bioavailability of metals to MPB. Increased concentrations of metals within the MPB could potentially increase their transfer to higher organisms through the food chain with potential impacts for biota. Whilst planktonic algae have been well studied with respect to metal uptake from the water column, there has been little research involving MPB and uptake of metals from sediment. The extent to which contaminant uptake by microphytobenthic algae occurs and under what conditions is therefore poorly understood. The research presented uses laboratory, mesocosm and field studies, to gain an understanding of processes governing metal bioavailability and mechanisms for uptake from sediment to the diatoms of the MPB under the complex and variable conditions of intertidal mudflats. A laboratory study using a single diatom species Cylindrotheca closterium found that uptake of cadmium (Cd) varied with sediment properties revealing the importance of sediment particle size and organic matter content in metal bioavailability to diatoms. Additionally, this study showed that the presence of diatoms altered Cd partitioning between sediment, overlying and pore water. Specifically there was an increase in Cd in the overlying and pore water when diatoms were present, indicating that diatoms mobilise metals from the sediment to the water column potentially increasing metal bioavailability to other biota. A study was conducted using an intertidal mesocosm to increase the realism of the study system and examine uptake to a natural MPB community. Diatoms were found to have higher concentrations of all the metals analysed (except tin) than other types of algae (filamentous and sheet macroalgae), confirming their importance as a study organism with respect to metal uptake and potential mobilisation through the food chain. Sediment disturbance was shown to increase metal uptake (iron, aluminium, vanadium and lead) from the sediment to algae. This is of concern due to predicted increases in storminess which are likely to increase sediment disturbance, with the likelihood that uptake of metals to diatoms will increase in the future. However, there were also indications of an antagonistic effect of temperature on disturbance, whilst disturbance increased bioavailability and uptake, increasing temperatures reduced uptake of some metals. This highlights the importance of considering the effects of multiple stressors in complex systems. Field studies showed that concentrations of some metals were related to their position on the mudflat whilst others were related to sampling date, indicating that there may be seasonal controls, such as to the presence of greater diatom biomass in spring and autumn, on metal uptake from the sediment. The research conducted has increased understanding of metal uptake to microphytobenthic diatoms from sediment and the influence they have in transferring metals from sediment to water, however the research also raises a number of new questions. For example, there appeared to be a link between sediment organic matter content and bioavailability of metals to diatoms, although the relative contribution of the diatoms, other algae, cyanobacteria and EPS to the sediment organic matter warrants further investigation. Furthermore, it has shown that the use of laboratory and mesocosm studies for this type of research can produce similar outcomes to those observed in the field but under more controlled and easily manipulated conditions, although field studies will continue to be vital in improving understanding of metals availability and transfer.
5

Determination and characterisation of trace metals and persistant oganic pollutants in Baynespruit river, Sobantu, KwaZulu-Natal, South Africa

Zuma, Vincent Thulani 06 1900 (has links)
This study assesses the presence of selected trace metals and pops in the Baynespruit River, Sobantu, KwaZulu-Natal. Sediments, plants and water samples were collected along the river during dry and wet season. For metal analysis, the extraction was done using acid digestion and then determined on the inductively coupled plasma atomic emission spectroscopy, for total metals in sediments, plants and water. Bio-available metals in sediments were analysed using atomic absorption spectroscopy. POPs were extracted in sediments using soxhlet extraction, which was followed up by evaporation on the rotary evaporator, sample clean up on a GPC column, further sample concentration on the rotary evaporator and later analysed on GC/MS instrument. Metals of concern in both seasons were Cu, Cr, Pb and Zn which exceeded maximum permissible limits for South African soil, Cr was just about the maximum permissible limit. The targeted POPs were not detected on any site during this work. / Environmental Sciences / M. Sc. (Environmental Science)

Page generated in 0.0827 seconds