Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2007. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-02-18T18:13:22Z No. of bitstreams: 1 2007_nadja_berenice.pdf: 879744 bytes, checksum: bd91158b542cad242ce4c020f69b7362 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-18T21:47:43Z (GMT) No. of bitstreams: 1 2007_nadja_berenice.pdf: 879744 bytes, checksum: bd91158b542cad242ce4c020f69b7362 (MD5) / Made available in DSpace on 2013-06-18T21:47:43Z (GMT). No. of bitstreams: 1 2007_nadja_berenice.pdf: 879744 bytes, checksum: bd91158b542cad242ce4c020f69b7362 (MD5) Previous issue date: 2007 / O presente estudo foi realizado na enseada do Saco da Mangueira, inserida na área urbana do município de Rio Grande, de suma importância do ponto de vista ambiental, econômico, cultural e de lazer que vem sendo progressivamente degradada em função da expansão urbana e industrial, principalmente a partir da década de 70. É um dos ecossistemas atingidos pelo processo de crescimento urbano sem restrição, fiscalização e planejamento adequado. Entre os impactos negativos estão os aterros das margens para empreendimentos imobiliários de empresas, indústrias e de favelas. Acrescenta-se a isto o lançamento de dejetos industriais e domésticos e disposição inadequada de resíduos sólidos. Teve como objetivo principal caracterizar a distribuição do Hg nos materiais dos aterros urbanos próximos ao Saco da Mangueira, visando avaliar a migração deste metal no sistema aquático. Para isso foram realizadas análises de Hg total, utilizando o sistema de vapor frio, acoplado a AAS GBS 932AA, em 22 amostras de material de aterro e 21 amostras de sedimento. Os materiais de aterros foram investigados nos intervalos de 0 - 5 e 5 - 20cm. Concluiu-se que todos os materiais de aterros estudados estavam contaminados por Hg sendo que no intevalo de 5 - 20cm foi encontrado a maior concentração em média de Hg (1,33mg kg-1). Foram selecionados cinco pontos para serem perfurados até o aquífero e analisados. Nestas amostras, observou-se, na maioria dos pontos, um pico na concentração do Hg nas camadas de material de aterro localizadas entre 20 – 60cm. Os sedimentos apresentaram variação na concentração do Hg total de 0,09 a 0,64mg kg-1, sendo que os maiores valores foram localizados nos pontos coletados na Coroa do Boi o que pode estar relacionado com descargas de efluentes domésticos e industriais nesta enseada. Não foi revelada a relação geográfica direta entre os locais de contaminação dos materiais de aterros por Hg e sedimentos próximos da beira do Saco da Mangueira. A extração não-sequencial do Hg demonstrou que o Hg está mais disponível nas amostras de solos do que nas amostras de sedimento, sendo que a fração trocável de Hg, prevaleceu. / The present study was realized in the embayment of the Saco da Mangueira, inserted in the urban area of Rio Grande. This area is important from of the point of view of an environment, economy, and leisure has been degraded progressively in function of the urban and industrial expansion, mainly starting from the decade of 70’s. It is one of the local ecosystems subjected to the urban growth without restriction, fiscal control and appropriate planning. Among the negative there are the embankments of the margins for companies and industries constructions and uncontrolled settlements. It also is used for inadequate dumping of solid industrial and domestic residues. The main objective of the current study was to characterize mercury distribution in coastal materials of the embankments and near shore sediments with the emphasize to evaluate the relocation of this metal in the aquatic system. The analyses of total Hg were realized in 22 material embankment samples and 21 sediment samples, using the system of cold vapor. The materials embankments were sampled in the intervals of 0-5 and 5-20cm. It was found that the materials embankments at all studied points were contaminated by Hg and the largest value of average concentration of Hg (1,33mg kg-1) was found in soil interval of 5-20cm. In five selected points the material embankment drilling was performed. It was observed that in most of the points, a pick of Hg concentration is located in interval of 20 - 60 cm. Mercury concentration in studied sediments varied from 0,09 to 0,64mg kg-1, and the largest values were found in the “Coroa do Boi”, what can be related to discharges of domestic and industrial effluents in this embayment. No geographical relationship between the concentration of total Hg in materials embankments and in sediments of Saco de Mangueira was found. The non-sequential extraction of Hg testified that Hg was more labil in the samples of materials embankments than in the sediment samples, and the exchangeable fraction of Hg prevailed.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A avaliaÃÃo da qualidade do sedimento tem sido vista como a extensÃo coerente e necessÃria de programas de avaliaÃÃo dos recursos aquÃticos. Os sedimentos apresentam-se como o mais preocupante dos compartimentos devido Ãs caracterÃsticas que favorecem a deposiÃÃo e acÃmulo de contaminantes. Estudos anteriores mostraram que o estuÃrio do rio Cearà vem sofrendo contaminaÃÃo por efluentes industriais e domÃsticos e que foi observada toxicidade a embriÃes de ouriÃo do mar expostos as Ãguas do estuÃrio. O objetivo do presente trabalho foi avaliar a qualidade ambiental de amostras de sedimento do estuÃrio do Rio CearÃ, atravÃs de anÃlises sedimentolÃgicas, quantificaÃÃo de metais e atravÃs de bioensaios em vÃrios compartimentos do sedimento. Foram realizadas trÃs Campanhas (Out/06, Jan/07 e Mai/07) em quatros estaÃÃes ao longo do estuÃrio. Como local de referÃncia foram amostrados sedimentos dos estuÃrios dos rios Malcozinhado e Pacoti. AnÃlises de granulometria, carbonatos, matÃria orgÃnica e ainda a anÃlise de Zn, Cu, Pb e Cr serviram para caracterizar as estaÃÃes. A toxicidade do sedimento integral foi avaliada em bioensaios com o anfÃpodo Tiburonella viscana e o copÃpodo Nitokra sp.; enquanto que embriÃes do ouriÃo do mar Lytechinus variegatus foram utilizados em testes na interface sedimento/Ãgua e com elutriatos. A caracterizaÃÃo da toxicidade de elutriatos foi realizada atravÃs de manipulaÃÃes fÃsicas e quÃmicas para AvaliaÃÃo e IdentificaÃÃo de Toxicidade (AIT). Foi observado um gradiente em relaÃÃo Ãs porcentagens de finos, matÃria orgÃnica e metais com valores decrescendo na direÃÃo da foz. De forma geral, as amostras coletadas no estuÃrio do rio Cearà foram tÃxicas em todas as rotas de exposiÃÃo. O teste com anfÃpodos mostrou boa reprodutibilidade, enquanto que a reproduÃÃo de copÃpodos teve grandes variaÃÃes no controle, entre as Campanhas. Para ambos os testes com embriÃes de ouriÃo do mar, a toxicidade foi elevada. A amÃnia parece ter contribuÃdo para toxicidade observada em amostras de elutriato, contudo manipulaÃÃes de adiÃÃo de EDTA, Tiossulfato de sÃdio, aeraÃÃo, filtraÃÃo e Ulva sp. reduziram a toxicidade das amostras sugerindo que alÃm da amÃnia, metais, compostos oxidÃveis, volÃteis e particulados contribuam para a toxicidade. A correlaÃÃo linear e a anÃlise dos componentes principais entre os parÃmetros abiÃticos, metais e toxicidade demonstraram que os parÃmetros pesquisados nÃo explicam totalmente a toxicidade observada nesse estudo. E apesar dos valores de metais encontrados no rio Cearà serem baixos em relaÃÃo a outros estuÃrios impactados, nÃveis elevados de toxicidade foram identificados em amostras de sedimento da regiÃo. / The evaluation of sediment quality has been seen as a consistent and necessary extension of assessment programmes for water resources. Sediments are the most concerning of the compartments due characteristics that favour the deposition and accumulation of contaminants. Previous studies showed that the estuary of Cearà River is suffering contamination by industrial and domestic effluents, and that toxicity was observed in embryos of sea urchin exposed to water of the estuary. The objective of the present study was to evaluate the environmental quality of sediment samples from the estuary of Cearà River, through sediment characterization, quantification of metals and bioassays in several compartments of the sediment. Three Campaigns were conducted (Oct/06, Jan/07 and May/07) at four stations along the estuary. As reference, sediments of the estuaries of Malcozinhado and Pacoti rivers were sampled. Analysis of granulometry, carbonate, organic matter and of the metals Zn, Cu, Pb and Cr served to characterize the stations. Toxicity of the whole sediment was evaluated in bioassays with the amphipod Tiburonella viscana and the copepod Nitokra sp.; whilst embryos of the sea urchin Lytechinus variegatus were used in tests at the interface sediment/water and with aqueous elutriates. The characterization of the toxicity of elutriates was accomplished through chemical and physical manipulation for the Evaluation and Identification of Toxicity (TIE). We observed a gradient on percentages of mud, organic matter and metals with values decreasing toward the mouth. In general, the samples from the estuary of Cearà River were toxic on all routes of exposure. The test with amphipods showed good reproducibility, whilst the reproduction of copepods showed large variations in the control, amongst the campaigns. Toxicity was high for both tests with sea urchin embryos. Ammonia seems to have contributed to the toxicity observed in samples of elutriate, however, manipulation of addition of EDTA, Sodium thiosulfate, aeration, filtration and the macroalgae Ulva sp. reduced the toxicity. This suggests that apart from ammonia, other factors such as metals, and oxidizable volatile and particulated compounds contribute to the toxicity. Linear correlation and principal components analysis between abiotic parameters, metals and toxicity demonstrated that the parameters investigated do not fully explain the toxicity observed in this study. Despite the values of metals found in the Cearà River were low relative to other impacted estuaries, high levels of toxicity were identified in samples of sediment from the region

Neste trabalho foi utilizada uma metodologia eletroanalítica para o estudo do comportamento dos pesticidas triazínicos, Atrazina e Ametrina em água e sedimentos do rio Mogi-Guaçu. Para isto utilizou-se a técnica de voltametria de onda quadrada (SWV) e o eletrodo de gota suspensa de mercúrio (HMDE). Inicialmente, os parâmetros experimentais (e voltamétricos) foram otimizados a fim de se obter a melhor resposta, em termos de intensidade de corrente de pico e definição do perfil voltamétrico. As melhores condições encontradas foram: eletrólito suporte CaCl2 0,01 mol L-1 em pH 3,0 e 2,3, para Ametrina e Atrazina, respectivamente, f = 100 s-1; a = 50 mV e DEs=2,0 e 10,0, para Ametrina e Atrazina respectivamente. Após a otimização, curvas de trabalho foram construídas para os dois pesticidas. Foram determinados os limites de detecção (LD) e quantificação (LQ), fatores de recuperação, repetibilidade, reprodutibilidade e sensibilidade da metodologia utilizada. Os resultados obtidos utilizando esta metodologia eletroanalítica foram comparados com os obtidos por HPLC-UV. Para Ametrina e Atrazina em eletrólito preparado com água do Milli-Q, os valores de LD encontrados foram de 2,12 ?g L-1 e 1,16 ?g L-1 e os de LQ foram de 7,06 ?g L-1 e 3,90 ?g L-1, respectivamente. Os valores de LD obtidos utilizando HPLC-UV para Ametrina e para a Atrazina foram de 2,69 ?g L-1 e 1,37 ?g L-1, enquanto aqueles para o LQ foram de 9,01 e 10,62 ?g L-1, respectivamente. Observou-se, desta maneira, que os resultados obtidos usando as duas técnicas são muito próximos e inferiores aos valores recomendados pela Comissão Nacional do Meio Ambiente (CONAMA) para águas residuais e efluentes industriais, 50 ?g L-1 para a Atrazina. Além disto, os valores reportados acima são tão baixos quanto os valores máximos aceitos pela Enviromental Protection Agency (EPA - USA) para águas potáveis, 3 ?g L-1 e pela Agência Nacional de Vigilância Sanitária (ANVISA), também para águas potáveis, 2 ?g L-1. A aplicação da mesma metodologia para águas naturais forneceu parâmetros importantes para verificar o comportamento destes pesticidas em águas, principalmente no que se refere à sua persistência. Foram determinados os limites de detecção (LD) e quantificação (LQ), assim como os fatores de recuperação para amostras de água do Rio Mogi-Guaçu, coletadas em três pontos diferentes, utilizando a técnica de SWV. Para Ametrina em eletrólito preparado com água do rio, os valores de LD variaram entre 15,41 e 29,54 ?g L-1 enquanto que os valores de LQ situaram-se entre 51,38 e 98,49 ?g L-1. Já para a Atrazina, os valores de LD variaram entre 4,90 e 6,19 ?g L-1 e os valores de LQ entre 16,36 e 20,65 ?g L-1 respectivamente. Os fatores de recuperação para Ametrina variaram entre 98,12 e 98,50% e para Atrazina entre 98,00 e 98,80%. As fotodegradações dos pesticidas foram estudadas com a exposição à radiação solar de soluções contendo os pesticidas e preparadas com água do Milli-Q, água de rio e água de rio contendo amostras de sedimentos. Os decaimentos da corrente de pico de redução da Ametrina e da Atrazina com o tempo de exposição à luz solar, variaram conforme o ponto de coleta da água do rio Mogi- Guaçu e a natureza do pesticida. Assim, para a Ametrina as porcentagens de decaimento de corrente após 32 horas de exposição foram de 19,10% (água do Milli-Q); 28,24% (ponto 1); 47,62% (ponto 2) e 30,92% (ponto 3). Já para a Atrazina, as respectivas porcentagens de decaimento das correntes de pico de redução foram de 37,50%; 45,90%; 46,10% e 36,53%. Para soluções contendo os sedimentos, a porcentagem de degradação ficou por volta de 30% para Ametrina enquanto que para a Atrazina a diferença foi marcante, ficando em torno de 86%. Os valores dos coeficientes das isotermas de adsorção de Freundlich obtidos indicaram uma dependência da adsorção com o teor de matéria orgânica e argila no sedimento para os três pontos de coleta do sedimento. De acordo com o critério adotado pelo IBAMA, os pesticidas Ametrina e Atrazina apresentam adsorção baixa, ficando pouco adsorvidos no sedimento. Os valores do 1/n da isoterma de Freundlich variaram entre 1,00 e 1,15 indicando uma característica de partição linear para todos os pontos. Os valores de matéria orgânica para os três pontos de coleta, variaram de 5,45 a 15,16%. A matéria orgânica encontra-se revestindo grande parte das frações minerais do solo e sedimento. Estas frações minerais variam de 15,7 a 20,8%, sendo os teores de silte de 12,3 a 16,3%. / An electroanalytical methodology was employed aiming to study the behaviour of the triazinic pesticides Atrazine and Ametrine in water and sediment collected from the Mogi-Guaçu River. The square wave voltammetry (SWV) and the hanging mercury drop electrode (HMDE) were employed. In a first step, the experimental (and voltammetric) parameters were optimized in order to yield the highest current signals as well as the most well defined voltammetric profiles. The best conditions were achieved as: 0.01 mol L-1 CaCl2 as the support electrolyte at pH 3.0 and 2.3 for Ametrine and Atrazine respectively, f = 100 s-1, a = 50 mV and ?Es = 2.0 and 10.0 for Ametrine and Atrazine respectively. After this initial step, analytical curves were obtained for both pesticides. The corresponding detection (LD) and determination (LQ) limits were calculated, as well as the recovering factors, repeatability, reproducibility and sensibility for the analytical methodology, which was compared with those, obtained using the HPLC-UV. For Ametrine and Atrazine, in pure electrolyte the LD values were 2.12 and 1.16 ?g L-1, while the LQ ones were 7.06 and 3.90 ?g L-1, respectively. The same parameters, obtained with HPLC-UV yielded LD values of 2.69 and 1.37 ?g L-1 for Ametrine and Atrazine, respectively, while the LQ ones were 9.01 and 10.62 ?g L-1, respectively. In this way, it is apparent that the results obtained in this work were very close for both techniques and lower than the minimum limit allowed by the Conselho Nacional do Meio Ambiente (CONAMA) for waste water or industrial effluents, 50 ?g L-1. Moreover, they are close to the maximum allowed value for drinking water postulated by the Environmental Protection Agency (EPA – USA), 3 ?g L-1 and the Agência Nacional de Vigilância Sanitária (ANVISA), 2 ?g L-1. The application of the same methodology for natural water samples yielded important parameters to establish the behaviour of pesticides, mainly concerning with its persistency. It were determined the detection and quantification limits and recovering factors by the SWV technique, for river water samples collected in three different points. For Ametrine, the LD values for electrolytes prepared with river waters, varied between 15.41 and 29.54 ?g L-1, while the values for LQ were between 51.38 and 98.49 ?g L-1. The same values for Atrazine were determined between 4.90 and 6.19 for LD and 16.36 and 20.65 for LQ. The recovering factors for Ametrine were found to be between 91.12 and 98.50% and for Atrazine between 98 and 98.8%. The photodegradations of pesticide molecules were studied by exposition to daylight of solutions containing the pesticides prepared with Milli-Q water, river water and river water containing sediments. The peak current decaying for Ametrine and Atrazine with exposition time varied accordingly the water collection point in the Mogi-Guaçu River and the nature of the pesticide. In this way, for Ametrine the percentage of decaying after 32 hours of exposition were 19.10% for Milli-Q water, 28.24% point 1, 47.62% point 2 and 30.92% point 3. For Atrazine, the respective decaying percentages of peak currents were 37.5%, 45.90%, 46.10% and 36.53% respectively. For solutions containing sediments (also collected in points 1, 2 and 3) the degradation percentage was around 30% for Ametrine, while for Atrazine the difference, around 86%. The coefficients from Freundlich adsorption isotherms presented values depending on the organic matter and clay present in the sediment samples. The pesticides presented low adsorption characteristic on the sediments. The 1/n values from Freundlich isotherm varied between 1.00 and 1.15, indicating a linear partition coefficient characteristic in all points. In this way, it is possible to associate the Kf values with the partition coefficients (Kd). The organic matter content for the three collection points varied between 5.45 and 15.15. The organic matter is found to be covering the mineral fractions of soils and sediments. These mineral fractions varied from 15.7 to 20.8%, while silt content were among 12.3 and 16.3%.

Compostos fenólicos vêm despertando preocupação nos últimos anos e incitando grande atenção em todo o mundo ao desenvolvimento de métodos de determinação e monitoramento contínuo no ambiente devido a sua elevada toxicidade e persistência no meio ambiente, principalmente no sedimento, que devido sua característica em acumular compostos faz desse um dos compartimentos mais importantes na avaliação do nível de contaminação de ecossistemas aquáticos continentais. Neste estudo foi desenvolvido um método analítico utilizando cromatografia a gás acoplada ao detector de espectrometria de massas (GC/MS) para a determinação de seis compostos fenólicos e foi avaliada a presença dos mesmos em amostras de sedimento do Reservatório Guarapiranga, um reservatório de usos múltiplos da água, destinado principalmente para abastecimento público de água potável da Região Metropolitana de São Paulo. Para garantir a reprodutibilidade do método de forma confiável atendendo aos objetivos e qualidade propostos, a metodologia desenvolvida foi submetida ao processo de validação, em que os parâmetros seletividade, linearidade, faixa de trabalho, limite de detecção, limite de quantificação, tendência/recuperação, precisão (repetitividade, precisão intermediária e reprodutibilidade) e robustez foram avaliados. A metodologia aqui proposta mostrou ser adequada para alcançar o objetivo de avaliar os compostos em estudo, e pela sua aplicação foi constatada a presença dos compostos fenol e 3-metilfenol no sedimento do reservatório. Nas amostras de sedimento coletadas em 2011, o fenol foi o composto encontrado com maior frequência, com alguns resultados acima do LQ, principalmente em pontos com maior influência urbana, em concentrações de 0,09 a 0,19 μg g-1. Também foi encontrado o 3-metilfenol com resultados acima do LQ em dois pontos de coleta, G-11 e G-13, nas concentrações de 0,10 e 0,19 μg g-1 respectivamente. Já na coleta realizada em outubro de 2014, o composto 3-metilfenol foi quantificado em dois pontos de coleta, G-02 e G-07, nas concentrações de 0,07 e 0,08 μg g-1 respectivamente, sendo detectado abaixo do LQ em diversos pontos ao longo do reservatório. A presença destes compostos mesmo em baixas concentrações pode indicar uma contaminação decorrente de atividades industriais nas margens do reservatório e considerando-se que os compostos em sedimento com o tempo podem ser liberados na coluna dágua e causar contaminação na água de abastecimento este estudo fornece subsídios para revisão da legislação vigente que não estabelece limites para os compostos fenólicos na matriz de estudo. / Phenolic compounds are molecules with increased toxicity and persistence in the environment, mainly in the sediment. Furthermore, these molecules are capable of accumulate compounds, making them one of the most important at the evaluation of the contamination level on aquatic ecosystems in the continent. These features increased the preoccupation in the last years, inciting great attention around the globe about the development of methods to determine and continuously monitor these compounds in the environment. In this study, a new analytical methodology was developed using gas chromatography mass spectrometry system (GC/MS) at the determination and evaluation of six phenolic compounds in sediment samples of the Guarapiranga Reservoir, a water reservatory with multiple uses, intended primarily for public drinking water supply in the Metropolitan Region of São Paulo, Brazil. This methodology was submitted to the validation process, to ensure the reproducibility of the method in a trustworthy way, according to the objectives and quality proposed. Selectivity, linearity, working range, detection limit, quantification limit, trend/recovery, precision (repeatability, intermediate precision and reproducibility) and robustness are the parameters evaluated in this process. This methodology revealed itself adequate to achieve the goal of evaluating the compounds studied. Through this method, it was verified that the compounds phenol and 3-methylphenol are present at the reservoir´s sediment. In sediment samples collected in 2011, phenol was the compound found most frequently, with some results above LQ, especially on points with greater urban influence, in concentrations from 0.09 to 0.19 μg g-1. It was also found 3-methylphenol with results above LQ on two collected points, G-11 and G-13 at concentrations of 0.10 and 0.19 μg g-1 respectively. In 2014, the 3-methyl phenol compound was quantified in two collected points, G-02 and G-07 at concentrations of 0.07 and 0.08 μg g-1 respectively, being detected below the LQ at various points along the reservoir. The presence of these compounds, even in low concentrations, can indicate a contamination from industrial activities at the reservoir margin. Considering that these compounds in the sediment can, with time, be released in the water column and contaminate the water supply, this study provides subsidies for a review of the current legislation, that do not sets limits to the concentration of phenolic compounds on sediment matrix.

Os hidrocarbonetos policíclicos aromáticos (HPAs) por serem considerados contaminantes persistentes, pela sua ubiqüidade no meio ambiente e pelo reconhecimento de sua genotoxicidade, têm estimulado atividades de pesquisa com o objetivo de determinar e avaliar as origens, transporte, transformação, efeitos biológicos e a acumulação em compartimentos de ecossistemas aquático e terrestre. Nesta dissertação, a matriz estudada foi o sedimento coletado na represa do Parque Pedroso em Santo André, SP. A técnica analítica empregada foi a cromatografia líquida em fase reversa com detector UV/Vis. O tratamento dos dados foi estabelecido durante o processo de desenvolvimento da metodologia para que houvesse confiabilidade nos resultados. As etapas envolvidas foram avaliadas usando o conceito da Validação de Ensaios Químicos. Os parâmetros selecionados para a validação analítica foram Seletividade, Linearidade, Intervalo de Trabalho, Sensibilidade, Exatidão, Precisão, Limite de Detecção, Limite de Quantificação e Robustez. Esses parâmetros apresentaram resultados satisfatórios, o que permite a aplicação da metodologia desenvolvida, sendo ainda um método simples que permite a minimização da contaminação e da perda de compostos por excesso de manipulação. Para os HPAs estudados não foram encontrados resultados positivos, acima do limite de detecção, em nenhuma das amostras coletadas na primeira fase. Já na segunda coleta foram encontradas pequenas alterações principalmente em acenaftileno, fluoreno e benzo[a]antraceno. Embora a área se encontre preservada, já se notam pequenos sinais de contaminação. / The polycyclic aromatic hydrocarbons (PAHs), by being considered persistent contaminants, by their ubiquity in the environment and by the recognition of their genotoxicity, have stimulated research activities in order to determine and evaluate their sources, transport, processing, biological effects and accumulation in compartments of aquatic and terrestrial ecosystems. In this work, the matrix studied was sediment collected at Pedroso Park\'s dam at Santo André, SP. The analytical technique employed was liquid chromatography in reverse phase with a UV/Vis detector. Statistics treatment of the data was established during the process of developing the methodology for which there was reliable results. The steps involved were evaluated using the concept of Validation of Chemical Testing. The parameters selected for the analytical validation were selectivity, linearity, Working Range, Sensitivity, Accuracy, Precision, Limit of Detection, Limit of quantification and robustness. These parameters showed satisfactory results, allowing the application of the methodology, and is a simple method that allows the minimization of contamination and loss of compounds by over-handling. For the PAHs tested were no found positive results, above the limit of detection, in any of the samples collected in the first phase. But, at the second collection, were found small changes mainly acenaphthylene, fluorene and benzo[a]anthracene. Although the area is preserved, it is possible to realize little signs of contamination.

Nitrification became the dominant nitrogen transformation in a number of lakes which accumulated ammonium, in hypolimnetic water, under aerobic conditions. The timing and duration of this activity varied between lakes but was characterized by decreasing ammonium, and increasing nitrate, concentrations. In Grasmere lake this phase was found to be due to the activity of planktonic chemolithotrophic nitrifying bacteria. The observed nitrate concentration increased during this phase and accounted for up to 15% of the total oxygen deficit of the hypolimnion. At similar in situ temperatures nitrification rates and nitrifying bacterial populations were greater in oxidised sediments than in the water column. Littoral sediments were more important than profundal sediments as sites of nitrification due to higher temperatures and the persistance of oxidising conditions to greater depths into these deposits. Within the littoral zone the physical characteristics of the sediment were important with organic rich deposits sustaining greater rates of nitrification than sandy sediments. Nitrate reduction was the primary determining factor of nitrate concentrations in sediment interstitial waters. Some observations on the culture of chemolithotrophic nitrifying bacteria from lakewater were discussed. Reviews of the methodology for nitrification research and nitrification in the lacustrine environment are presented.

Changes in sediment morphology on the West Florida Shelf is investigated over a 14-year time period using multibeam bathymetry and backscatter in water depths between 10 m and 20 m, off the coast of Indian Rocks Beach, Pinellas County, Florida. Bathymetric surveys collected in 2002 (Kongsberg EM 3000 at 300 kHz) and 2016 (Reson 7125 at 400 kHz) were processed using CARIS Hips and Sips to create bathymetric maps and backscatter images. These data were then interpreted and compared in order to test hypotheses and answer questions related to sediment migration and sediment volume change. The following questions prompted this study: A. How mobile is the sediment on the limestone? B. What sedimentary changes occurred following the 2002 and 2003 deployments of mines for an Office of Naval Research project? C. How much sediment was removed during dredging and how closely does it compare to the Army Corps of Engineers’ reported estimate during the beach renourishment of Sand Key in 2012? In order to answer these questions, hypotheses were proposed: Hypothesis A: The sediment ridges in the study site have not migrated significantly over the limestone hard bottom during the 14-year time period (Hafen, 2001; Edwards et al. 2003). Hypothesis B: There is no change in sediment volume where the mine-like object were placed and removed after the ONR mine burial experiment (Wolfson 2005 Wolfson et al. 2007). Hypothesis C: Changes in sediment volume between 2002 and 2016 will match the amount estimated by the Army Core of Engineers who dredged the area. Results show that the sediment ridges in the study area had some migration over the limestone hard bottom during the 14-year time period. The results also found that there was a sediment volume change where mine-like objects were placed and removed during the Office of Naval Research mine burial experiment because of a dredging operation in 2012 that dredged sediment from the experimental area. Specific areas investigated that surround the dredging area showed significant loss of sediment, with the change in hydrodynamics from dredging influencing this sediment loss. The volume of sediment removed from the aforementioned dredging cut was found to be within 16% of that estimated in the Army Corps of Engineers report prior to the dredging. Geologic interpretations of the backscatter images interpreted strong backscatter returns as limestone, mid strength returns as coarse shell hash and weak returns as fine to medium-grained sediments. The weak returns were found primarily on the sediment ridges. The dredging cut showed stronger returns than the surrounding ridge, indicating that underlying coarse sediments were most likely compacted and composed of shell hash. Using satellite remote sensing as a way to gather continual repeat coverage at high resolution (2 m) data to determine absolute depth in these water depths is investigated and preliminary results suggest that processed 250 m pixel MERIS data will give a similar depth range as multibeam bathymetry. The higher-resolution 0.5 m pixel raw WorldView 2 data shows NW-SE trending structure, suggesting the seafloor morphology will be more visible.

Understanding of the processes of sediment transfer within, and from, glaciated catchments is of fundamental importance in order to establish rates of sediment transfer and resultant landscape evolution. Rates of glacio-fluvial sediment transfer are strongly controlled by glacier meltwater runoff and the availability of sediments for entrainment. However, it is becoming apparent that recently deglaciated forefields can modify the patterns of suspended sediment transfer. Glacier shrinkage exposes areas of unstable glacigenic sediments that can be subject to reworking and redistribution, and, as these environments become ice-free, heightened levels of geomorphological activity (so-called 'paraglacial' activity) are also likely to have a significant impact on both sediment and water yields from deglaciating catchments. Consequently, questions are raised as to the impacts of deglaciation upon contemporary and future rates of suspended sediment transfer, and the resultant fluvial sediments loads and rates of landscape adjustment. Therefore, the aim of this research was to present an integrated study of how sediment transfer in a glaciated catchment functions during, and is responding to, deglaciation. A variety of techniques were employed to examine the hydrological functioning of an Alpine glacier, the Feegletscher Nord, Switzerland, and the resultant temporal and spatial patterns of sediment transfer in light of catchment hydrology, ablation processes and forefield geomorphology. Data was collected over two field campaigns in 2010 and 2012 to capture the inputs, throughputs and outputs of meltwater and sediment. This research found that patterns of sediment transfer were modified within the proglacial zone, reinforcing previous findings that the location of proglacial monitoring is important in determining the observed patterns of sediment transfer. These patterns of sediment transfer were attributed to variations in forefield sediment availability, which appeared to demonstrate marked spatial variability. This variability was hypothesised to be influenced by the geomorphological characteristics of the forefield, including rock fall debris that appeared to limit sediment availability, and glacigenic sediment deposits that enhanced the availability of in-channel and channel-marginal sediments. These findings suggest that the investigation of rates of sediment transfer and paraglacial sedimentation may be complicated in catchments that have experienced complex geomorphological responses to deglaciation. In addition, the investigation of sediment transfer processes and the development of a glacier runoff model enabled the exploration of future suspended sediment loads with progressive deglaciation and a changing climate. Suspended sediment loads were predicted to experience rapid declines until the end of the 21st Century due to reductions in meltwater runoff as glacier extent is reduced. However, it is suggested that uncertainties in future sediment availability limit the usefulness of such forecasts. Consequently, this research highlights how the understanding of both sedimentary and hydrological processes in glaciated catchments may be enhanced by consideration of the changes that can occur in these environments associated with glacier shrinkage and a changing climate.

Master of Science / Department of Geology / Saugata Datta / Elevated levels of dissolved arsenic (As), iron (Fe) and manganese (Mn) are seen in the shallow, anoxic groundwaters of southeast Bangladesh on the Ganges- Brahmaputra- Meghna River delta. Over the past decade the mechanisms of As release have been widely debated. It is understood that As can sorb onto Fe-bearing minerals and can be subsequently released when reactions, such as microbially driven processes, occur. This study takes a multi disciplinary approach to understand the extent of the natural reactive barrier along the Meghna River and to evaluate the role of the natural reactive barrier in As sequestration and release in groundwater aquifers. River water and groundwater interactions occur in the hyporheic zone, which is defined as the transient subsurface region where river water and groundwater mix. The natural reactive barrier can develop within the hyporheic zone, where Fe-bearing minerals accumulate with a potential for As sorption, along with reworking and re-deposition of sediments along the riverbank. Shallow sediment cores, and groundwater and river water samples were collected from the east and west banks of the Meghna River in Jan. 2016. Groundwater and river water samples were tested for total dissolved Fe, Mn, and As concentrations; δ₂H, δ₁₈O isotopic ratios. Fluorescence spectroscopic characterization of groundwater organic matter provided insight into the hydro-geochemical reactions active in the groundwater and the hyporheic zone. Eight sediment cores of ~1.5 m depth were collected ~10 m away from the edge of the river. Vertical solid-phase concentration profiles of Fe, Mn, and As were measured by four different methods (hand-held XRF, and ICP-OES analysis of 3 digestions: aquaregia (HNO₃: HCl 1:3), 1.2 M HCl, and 1 M NaH₂PO₄ + 1 M L-ascorbic acid extractions). Enrichment of solid phase Fe, Mn, and As and the presence of possible Fe and Mn oxides in the sediments illustrate the existence of an natural reactive barrier at this reach of the Meghna. HCl extractions of sediment revealed solid-phase As accumulation along the west riverbank reaching concentrations of ~1500 mg/kg. Aqueous geochemical results showed the highest dissolved As concentrations in shallow wells (<30 m depth), where organic matter was fresh, humic-like, and aromatic. Humic-like dissolved organic matter present in the groundwater may enhance Fe oxide dissolution. Microbial reduction of organic matter prompts the reduction of Fe³⁺ to Fe²⁺, causing As to mobilize into groundwater. This study quantified the extent of As accumulation in the sediments along a 1 km stretch of the Meghna River. These findings contribute to the understanding of geochemical processes involved in As release into groundwaters from sediments within a fluvial deltaic environment.

Storms play a significant role in beach morphodynamics. Storm-induced beach-profile changes and their longshore variations are investigated in this study. The impacts of four summer tropical storms and two series of winter storms over the last 10 years along the coast of Treasure Island were documented. Tropical storms Alberto in 2006, Fay in 2008, Debby in 2012, Hermine in 2016 and winter storms in winter seasons of 2014 and 2015 are discussed in this study. In general, the Treasure Island beach experienced more erosion generated by tropical storms with greater intensity, but shorter duration, as compared to winter storms due to lower waves, weaker wind and smaller storm surge. Winter storms typically do not generate high storm surge and generally do not cause erosion at the dune and back beach unless the pre-storm beach is very narrow. Based on pre- and post-storm beach-profile surveys along the coast of Treasure Island, the northern end of the barrier island, located directly downdrift of the John’s Pass tidal inlet, experienced erosion along the entire profile during the storms. Along the middle part of Treasure Island, dry beach suffered erosion during both the tropical storms and winter seasons while the nearshore zone suffered erosion during the tropical storms and experienced deposition during the winter seasons. Sunset Beach at the southern end experienced severe erosion during tropical storm Debby, but not during other storms. Winter seasons caused relatively small changes to the morphology of Sunset Beach. Deposition happened in the nearshore zone along Sunset Beach during winter storms. Survey line R143 at the very south end of Treasure Island suffered erosion in tropical storm Alberto, Debby and Hermine. Beach profile changes induced by Tropical storm Fay was different as compared to other tropical storms. Considerably less beach erosion occurred due to the large distance of the storm path from the study area. Overall, Sunshine Beach, bounded by John’s Pass inlet at northern end of Treasure Island, was influenced both by wave conditions and the tidal flows. Sediment transport was to the north along the coast of Sunshine Beach when wind direction was from south, e.g. during tropical storm Fay. However the northward sediment transport was blocked by the John’s Pass jetty. Therefore, deposition occurred at Sunshine Beach during tropical storm Fay. When wind direction was from north (e.g. during tropical storms Alberto and during the winter seasons), southward sediment transport was generated. Erosion occurs during the northerly approaching storms. The morphodynamics of the middle section of Treasure Island are influenced by the sand supply at the attachment point of John’s Pass ebb delta. Sunset Beach experienced various levels of erosion during the tropical storms not only because of the high wave, strong wind and high water level generated by storms, but also due to the higher waves associated with an offshore dredged pit.