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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.
151

Avaliação sistemática do uso do Dried Blood Spot para determinação de elementos químicos em sangue capilar visando estudos de biomonitoramento no Brasil / Systematic evaluation of the use of Dried Blood Spot for determination of chemical elements in capillary blood in order biomonitoring studies in Brazil

Caran, Nara da Cruz Carolli 24 March 2016 (has links)
A biomonitorização humana ou biomonitoramento (BH) é definido como a medida periódica de determinada substância química ou seu metabólito em fluidos biológicos, principalmente sangue e urina, de uma população com o objetivo de avaliar a exposição e os riscos à saúde. Tal método tem se tornado comum em países desenvolvidos, porém ainda é uma prática pouco utilizada no Brasil. Isso ocorre pela dificuldade de coleta, armazenamento e transporte das amostras, principalmente em regiões sem infraestrutura e de difícil acesso. Diante disso, alguns procedimentos alternativos de coleta de amostra vêm sendo propostos. Um destes procedimentos é o Dried Blood Spot (DBS) ou coleta e armazenamento de amostra em papel-cartão. Este método oferece uma série de vantagens sobre os procedimentos de coleta convencionais, principalmente por reduzir consideravelmente o volume de amostra coletada. Entretanto, pouco se sabe sobre a estabilidade dos analitos após a deposição da amostra no cartão e do risco de contaminação da amostra pelo substrato sólido. Além disso, procedimentos de extração dos analitos do papel, para posterior quantificação, ainda não estão totalmente estabelecidos. Neste sentido, o presente trabalho avaliou de forma sistemática o procedimento de coleta de sangue por DBS visando sua futura aplicação em programas de biomonitoramento no Brasil para determinação dos elementos químicos As, Cd, Cu, Hg, Mn, Pb, Se e Zn por espectrometria de massas com plasma indutivamente acoplado (ICP-MS). Para isso, no estudo foram utilizadas três diferentes marcas comerciais de cartão coletor: Whatman 903(TM), Munktell(TM), e DMPK-C(TM). Todas as marcas de cartão apresentaram baixas concentrações dos elementos químicos. Após a deposição da amostra no papel cartão verificou-se que a concentração dos elementos químicos manteve-se estável por um período de pelo menos 60 dias (temperatura ambiente e ao abrigo da luz). Foi otimizado o método de extração dos analitos do substrato, com melhor condição obtida após a imersão do papel (corte circular de diâmetro de 1/2´´) por 60 minutos em solução extratora (0,5% v/v HNO3 e 0,01% v/v Triton(TM) X-100) na proporção de 1:50 v/v, seguida de 10 segundos de agitação por vortex. Após a extração, a solução resultante contendo os analitos foi diretamente injetada no ICP-MS. Cabe também destacar que não foram observadas diferenças estatísticas nas concentrações dos elementos químicos com coleta de sangue da veia do antebraço (sangue venoso) ou do dedo (sangue capilar). Os resultados obtidos no presente estudo, devem contribuir para a implementação deste procedimento em análises de elementos químicos (biomonitoramento da população brasileira), principalmente considerando as dificuldades de coleta, armazenamento e transporte de amostras clínicas em nosso país por sua extensão territorial. Além disso, este procedimento pode facilitar estudos com populações vulneráveis e que vivem em áreas remotas e de difícil acesso. / Human biomonitoring or biomonitoring (BH) is defined as the measurement of a particular chemical or metabolites in biological fluids, especially blood and urine, in a population to assess the level of exposure and health risks. Human biomonitoring is a common activity in developed countries, but is still an uncommon practice in Brazil. It mainly occurs due to the difficulty of collection, storage and transport of samples, particularly in regions without infrastructure and difficult access. Therefore, some alternative procedures for sample collection have been proposed. One of the procedures is the Dried Blood Spot (DBS). This method offers distinct advantages over conventional sample collection procedures, including the reduced sample volume required for analysis. However, little is known about the stability of analytes after sample deposition on the card and the possible risk of sample contamination by the solid substrate. In addition, the extraction procedures of elements from the substrate surface before determination are not yet fully established. In this sense, the present study evaluated systematically the DBS blood collection procedure aiming at its future application in biomonitoring studies in Brazil to determine the chemical elements As, Cd, Cu, Hg, Mn, Pb, Se and Zn by inductively coupled plasma mass spectrometry (ICP-MS). For this, the study used three different brands of collecting cards: Whatman 903(TM), Munktell(TM), and DMPK-C(TM). All card brands presented low concentrations of chemical elements. After sample deposition on cardboard it was found that the concentration of chemical elements remained stable for at least 60 days (at room temperature and protected from light). It was optimized the method of analytes extraction from the substrate, with the best condition obtained after immersing the paper (circular cutting diameter of 1/2 \'\') for 60 minutes in an extraction solution containing 0,5% v/v HNO3 and 0,01% v/v Triton(TM) X-100 in the ratio 1:50 v/v, followed by 10 seconds of vortex. After extraction, the resulting solution containing the analytes was directly injected into the ICP-MS. It can also be pointed out that no statistical differences was found between the concentrations of elements determined in forearm vein blood (venous blood) and finger blood (capillary blood). Taken together, the results of the present study can contribute to the employment of the DBS procedure for the screening of chemical elements in the Brazilian population, especially considering the difficulties of collection, storage and transport of clinical specimens in our country. Moreover, studies in vulnerable populations living in remote areas and of difficult access should be simplified.
152

Macroinvertebrados como bioindicadores em riacho tropical: uma avaliação de impactos por sedimentação, rompimento de barragem e de recuperação após medidas de restauração / Macroinvertebrates as bioindicators in tropical stream: an evaluation of impacts by sedimentation, dam rupture, and recuperation after restoration project application

Pinto, Thandy Junio da Silva 07 February 2018 (has links)
Alterações antrópicas em ecossistemas aquáticos exigem medidas de recuperação dos ambientes degradados, destacando-se projetos de restauração ecológica. Uma das etapas cruciais nesses projetos é a fase de monitoramento, sendo que o uso de macroinvertebrados como bioindicadores apresenta-se como uma importante ferramenta, por eles oferecerem vantagens sobre outros métodos de avaliação. Assim, o objetivo foi verificar os efeitos do assoreamento, antes e depois do rompimento da barragem de um pequeno reservatório em um riacho tropical, sobre a assembleia de macroinvertebrados aquáticos e avaliar a resposta da estrutura da comunidade após a implementação de um projeto de restauração ecológica. A pesquisa foi conduzida no riacho da Campininha, que passou por diversas alterações antrópicas, destacando-se aqui o rompimento de uma barragem e posteriormente a todos esses distúrbios pela implementação de um projeto de restauração ecológica. Foi realizada revisões da literatura para verificação da aplicabilidade da comunidade de macroinvertebrados como bioindicadores de sedimentação e na avaliação de projetos de restauração ecológica. Foram coletados dados pré-existentes antes e após o acidente e realizadas campanhas amostrais dois anos após o início da implantação do projeto de restauração. A comunidade de macroinvertebrados foi avaliada pela aplicação de índices ecológicos estruturais e funcionais alimentares e os resultados analisados por meio de ferramentas de estatística uni e multivariada. A análise da literatura mostrou que a aplicação de índices ecológicos tradicionais, tais como riqueza e diversidade, podem não ser sensíveis o suficiente para indicar impactos relacionados à sedimentação e implementação de projetos de restauração ecológica. Sendo, assim, necessária a utilização de índices que considerem a composição da comunidade, a sensibilidade dos organismos e a utilização de grupos funcionais alimentares e suas relações. Antes do rompimento da barragem a comunidade de macroinvertebrados já apresentava-se empobrecida pelo assoreamento do trecho represado e do canal fluvial. O rompimento da estrutura implicou na perda de importantes grupos e na mudança da composição da comunidade, além da perda de grupos funcionais alimentares, com consequente perda de funções ambientais. Após a implementação do projeto de restauração houve o aparecimento de 20 famílias, no entanto, os índices ecológicos tradicionais não foram capazes de identificar mudanças na comunidade. Métricas de composição e de grupos alimentares apontaram para um processo de recuperação da área. As características do sedimento tiveram um alto poder explicativo da comunidade, mostrando que a recuperação do habitat bentônico é um dos fatores que leva à uma melhor resposta da comunidade, mesmo esse não tendo sido o foco da aplicação do projeto de restauração avaliado. O relativo curto período transcorrido após a implementação do projeto já foi suficiente para indicar melhorias na qualidade ambiental. Tais resultados contrapõe a maioria dos estudos verificados na revisão da literatura. No entanto destaca-se que os mesmos foram conduzidos principalmente em ambientes temperados, indicando que em ambientes tropicais a dinâmica de recuperação é diferente. Assim aponta-se a necessidade da intensificação da implantação de projetos e monitoramento dos mesmos para a criação de um arcabouço teórico para auxiliar gestores e projetistas na sua elaboração. / Anthropic alterations in aquatic ecosystems demand the implementation of recuperation actions, highlighting ecological restoration projects. The monitoring is an important step to these projects, and the macroinvertebrates application as bioindicators is an important tool, because they are advantageous in comparison to another assessment methods. Thus, the goal was verify the effects of silting, and dam rupture in macroinvertebrate community, in a tropical stream, and assess the answer to an ecological restoration project implementation. The research was conducted in the Campininha stream, that was impacted by anthropic alterations, featured a dam rupture and after all this disturbances was implemented an ecological restoration project. A literature review was conducted to verification of the applicability of macroinvertebrates as bioindicators of silting and in ecological restoration projects assessment. Data was collected before and after the dam rupture, and samplings were done two years after the project implementation began. The macroinvertebrates community was assessed by application of structural and functional feeding indexes and the results analyzed by univariate and multivariate statistic. The literature review showed that the traditional indexes application may be not sensible to indicate impacts related to silting and ecological restoration projects implementation, and it is necessary the utilization of indexes that consider the community composition, organisms sensibility and functional feeding groups and your relations. Before the dam rupture, the macroinvertebrate community was already poor by the silting of the lake and fluvial channel. The dam rupture leaded to the loss of important groups and in the change of the macroinvertebrate community composition, also loss of functional feeding groups and consequently environmental functions. After the ecological restoration project implementation were found another 20 families, however, the traditional indexes were not sensible to indicate changes in macroinvertebrates community. Composition and functional feeding groups indexes showed the stream recuperation process. The sediment characteristics had a community high explanative power showing that the benthic habitat recovery is a factor that guide to a better community answer, even this was not the goal of the restoration project application. The relative short time after the project implementation was enough to point a environmental quality recovery, in contrast with the literature review. However the most studies analyzed was conducted in temperate environments, showing that in tropical environments the recovery dynamics is different. Thus, is necessary a intensification of restoration projects implementation and monitoring to a creation of data bases to guide managers and professionals responsible by the projects elaboration in decision make.
153

Utilisation du comportement natatoire de Daphnia magna comme indicateur sensible et précoce de toxicité pour l'évaluation de la qualité de l'eau / Use of Daphnia magna swimming behavior as a sensitive and early indicator of toxicity for water quality assessment

Chevalier, Julie 30 October 2014 (has links)
Les paramètres comportementaux sont de plus en plus considérés comme étant des indicateurs sensibles et précoces de toxicité chez les organismes aquatiques. Cependant, l’utilisation du comportement natatoire comme critère de toxicité pour l’analyse de risque environnemental ou pour le contrôle de la qualité de l’eau reste pour l’heure encore limitée. En effet, il est actuellement difficile de quantifier la sensibilité des paramètres comportementaux et d’établir un lien entre les seuils d’effets comportementaux et les effets aigus et subaigus classiquement mesurés dans les tests en écotoxicologie. Dans le but d’améliorer notre compréhension des effets comportementaux des polluants sur Daphnia magna, nous avons développé un nouveau système de mesure du comportement multi-cuves baptisé «Multi-DaphTrack ». Douze substances toxiques, couvrant une large gamme de modes d’action différents ont été testées dans ce système. Un test standard d’immobilisation ainsi que des analyses de comportement dans le toximètre DaphToxI®, ont également été effectués pour chaque substance afin de comparer les seuilsd’effets comportementaux avec les paramètres classiques d’immobilisation. Les résultats des expositions aux différentes substances ont démontré que notre nouveau système d’exposition multi-cuves permet de détecter des effets comportementaux (i.e.,augmentation de la vitesse de nage) significatifs et précoces pour l’ensemble des substances testées et ce, à des concentrations proches de la CE10(48 h) du test aigu d’immobilisation dès la première heure d’exposition. Des profils comportementaux différents ont été observés selon les substances testées (i.e., intensité, temps de latence et durée de l’effet) mais ceux-ci ne sont pas spécifiques d’un mode d’action particulier. Les résultats obtenus avec le toximètre DaphToxI®ont révélé des profils d’effet similaires (i.e.,augmentation de la vitesse de nage) bien que ce système soit globalement moins sensible par rapport au système «Multi-DaphTrack». Pour conclure, notre nouveau système d’exposition multi-cuves «Multi-DaphTrack» est un outil plus sensible et précoce que letest standard d’immobilisation pour l’évaluation de la toxicité de substances chimiques. L’utilisation du système «Multi-DaphTrack» pourrait donc être envisagée, après quelques améliorations et validation supplémentaires, pour l’évaluation de la qualité des masses d’eauet des effluents. / Swimming behavior is increasingly reported as a sensitive and early indicator of toxicant stress in aquatic organisms. However, it remains unclear how to quantify the sensitivity of swimming behavioral endpoints and how to compare these effect thresholds with standard ecotoxicological endpoints used in risk assessment. To date, the systematic assessment of the sensitivity of swimming behavioral endpoints in daphnia is limited because of the restrained test capacity of existing behavioral analysis systems. Hence, we developed a new behavioral analysis multi-cellsystemnamed “Multi-DaphTrack” with a high throughput testing capacity in order to enhance our understanding of swimming behavioral effects in Daphnia magnaunder chemical exposure. Twelve compounds covering different modes oftoxic action were selected and tested in this new system andin a single-cell commercialized biomonitor (DaphToxI®) and with the acute standard test.Our new multi-cellexposure system detectedsignificant and early swimming behavioral effects (i.e.,increase of the average speed) for most of the tested compounds and this, from the first hour of exposure at concentrations near the EC10(48h). Contrastedbehavioral profiles were observed for average speed (i.e., intensity, time of effect onset, effect duration), but no distinct behavioral profiles could be drawn from the chemical mode of action. Despite less sensitive,the DaphToxI®gave similar trends (i.e.,rapid peak increase) compared to our “Multi-DaphTrack” system. To conclude, behavior analysis using our “Multi-DaphTrack”systemcould be used as an alternative or complement to the current acute standard test for toxicity assessment of chemicals. With some additional improvements and validations, it also could be used forquality assessment of waterbodiesand sewages.
154

Evaluation of Biomarker Responses in Fish : with Special Emphasis on Gill EROD Activity

Andersson, Carin January 2007 (has links)
Many chemicals present in the aquatic environment can interfere with physiological functions in fish. Exposure to chemicals can be revealed by the use of biomarkers. Induction of 7-ethoxyresorufin O-deethylase (EROD) activity is a commonly used biomarker for exposure to CYP1A inducers such as dioxins and polyaromatic hyrdrocarbons. Vitellogenin is a frequently used biomarker for estrogenic compounds in various fish species whereas a biomarker for androgens, spiggin, is only found in sticklebacks. The main objectives of this thesis were to evaluate gill EROD activity as a biomarker and the three-spined stickleback as a model species in ecotoxicological studies. EROD activities were measured in gill, liver and kidney in rainbow trout (Oncorhynchus mykiss) caged in urban areas in Sweden. EROD induction was most pronounced in the gill. Also in fish caged at reference sites, with an expected low level of known CYP1A inducers, a marked gill EROD induction was found. One suggested inducer in rural waters is humic substances (HS). To evaluate the EROD-inducing capacity of HS, three-spined sticklebacks (Gasterosteus aculeatus) were exposed to HS of natural or synthetic origin. Both kinds of HS caused significant EROD induction. Gill EROD activities were also induced in sticklebacks exposed to ethynylestradiol (EE2) and β-naphthoflavone (βNF), alone and in combinations. Production of vitellogenin was induced in sticklebacks exposed to ≥50 ng EE2/l and a significant decrease in spiggin production was observed in individuals exposed to 170 ng EE2/l. Results from this thesis further strengthen the contention that gill EROD activity is a very sensitive biomarker for CYP1A inducers and that the stickleback is a suitable biomonitoring species, especially for exposure to CYP1A inducers. The finding that not only classical CYP1A inducers but also HS and high EE2 concentrations stimulate gill EROD activity is of significance for the interpretation of biomonitoring data.
155

Environmental Chemistry of Commercial Fluorinated Surfactants: Transport, Fate, and Source of Perfluoroalkyl Acid Contamination in the Environment

Lee, Holly 19 June 2014 (has links)
Perfluoroalkyl carboxylates (PFCAs) and perfluoroalkane sulfonates (PFSAs)are anthropogenic fluorinated surfactants that have been detected in almost every environmental compartment studied, yet their production and applications are far outweighed by those of other higher molecular weight fluorinated surfactants used in commerce. These fluorinated surfactants are widely incorporated in commercial products, yet their post-application fate has not been extensively studied. This thesis examines various biological and environmental processes involved in the fate of these surfactants upon consumer disposal. Specific focus was directed towards the environmental chemistry of polyfluoroalkyl phosphate esters (PAPs), perfluoroalkyl phosphonates (PFPAs), and perfluoroalkyl phosphinates (PFPiAs), and their potential roles as sources of perfluoroalkyl acids (PFAAs) in the environment. PAPs are established biological precursors of PFCAs, while PFPAs and PFPiAs are newly discovered PFAAs in the environment. Incubation with wastewater treatment plant (WWTP) microbes demonstrated the ability of PAPs to yield both fluorotelomer alcohols (FTOHs), which are established precursors of PFCAs, and the corresponding PFCAs themselves. WWTP biosolids-applied soil-plant microcosms revealed that PAPs can significantly accumulate in plants along with their degradation metabolites. This has implications for potential wildlife and human exposure through the consumption of plants grown and/or livestock raised on farmlands that have been amended with contaminated biosolids. A number of compound-and environmental-specific factors were observed to significantly influence the partitioning of PFPAs and PFPiAs between aqueous media and soil, as well as, aquatic biota during sorption and bioaccumulation experiments respectively. In both processes, PFPAs were primarily observed in the aqueous phase, while PFPiAs predominated in soil and biological tissues, consistent with the few environmental observations of these chemicals made to date. Detection of the PAP diesters (diPAPs), PFPiAs, and fluorotelomer sulfonates (FTSAs),all of which are used commercially, in human sera is evidence of human exposure to commercial fluorinated products, but the pathways by which this exposure occurs remain widely debated. Overall, this work presents novel findings on the environmental fate of commercial fluorinated surfactants and each of the process studied shows a clear link between the use of commercial products and the fluorochemical burden currently observed in the environment.
156

Environmental Chemistry of Commercial Fluorinated Surfactants: Transport, Fate, and Source of Perfluoroalkyl Acid Contamination in the Environment

Lee, Holly 19 June 2014 (has links)
Perfluoroalkyl carboxylates (PFCAs) and perfluoroalkane sulfonates (PFSAs)are anthropogenic fluorinated surfactants that have been detected in almost every environmental compartment studied, yet their production and applications are far outweighed by those of other higher molecular weight fluorinated surfactants used in commerce. These fluorinated surfactants are widely incorporated in commercial products, yet their post-application fate has not been extensively studied. This thesis examines various biological and environmental processes involved in the fate of these surfactants upon consumer disposal. Specific focus was directed towards the environmental chemistry of polyfluoroalkyl phosphate esters (PAPs), perfluoroalkyl phosphonates (PFPAs), and perfluoroalkyl phosphinates (PFPiAs), and their potential roles as sources of perfluoroalkyl acids (PFAAs) in the environment. PAPs are established biological precursors of PFCAs, while PFPAs and PFPiAs are newly discovered PFAAs in the environment. Incubation with wastewater treatment plant (WWTP) microbes demonstrated the ability of PAPs to yield both fluorotelomer alcohols (FTOHs), which are established precursors of PFCAs, and the corresponding PFCAs themselves. WWTP biosolids-applied soil-plant microcosms revealed that PAPs can significantly accumulate in plants along with their degradation metabolites. This has implications for potential wildlife and human exposure through the consumption of plants grown and/or livestock raised on farmlands that have been amended with contaminated biosolids. A number of compound-and environmental-specific factors were observed to significantly influence the partitioning of PFPAs and PFPiAs between aqueous media and soil, as well as, aquatic biota during sorption and bioaccumulation experiments respectively. In both processes, PFPAs were primarily observed in the aqueous phase, while PFPiAs predominated in soil and biological tissues, consistent with the few environmental observations of these chemicals made to date. Detection of the PAP diesters (diPAPs), PFPiAs, and fluorotelomer sulfonates (FTSAs),all of which are used commercially, in human sera is evidence of human exposure to commercial fluorinated products, but the pathways by which this exposure occurs remain widely debated. Overall, this work presents novel findings on the environmental fate of commercial fluorinated surfactants and each of the process studied shows a clear link between the use of commercial products and the fluorochemical burden currently observed in the environment.
157

Spatial distribution of the nutrient plume emanating from an Integrated Multi-Trophic Aquaculture (IMTA) farm in British Columbia: use of an in-situ kelp bioassay to monitor nutrient loading.

Prussin, Emrys Adain 25 May 2012 (has links)
To assess the spatial distribution of nutrient wastes around an open-water integrated fish/mollusk/kelp farm in-situ kelp bioassays were employed. Growth rates were measured over a four-month growing season and used as a proxy for relative nutrient concentrations. Seasonality and depth effects on growth rate were also assessed. Growth around the pens was 0.20 cm • day-1 higher than at the control, and reached a maximum of 1.4 cm • day-1. Optimal growth was achieved at 8 m. Growth at 8 m was significantly higher by 1.5 cm • day-1 compared to surface waters at 2 m. Early spring had the highest growth rates with a peak of 1.4 cm • day-1 recorded on June 21. This study re-iterates the fundamental benefits of IMTA and shows the potential of in-situ assay as an alternative to error-prone and costly water sampling to asses nutrient status in water. / Graduate
158

Análise multielementar em folhas de Nerium oleander L. usando fluorescência de raios X por dispersão em energia / Multielement analysis in leaves of Nerium oleander L. using energy dispersive X-ray fluorescence

Ramon Silva dos Santos 04 August 2014 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Desde o início do século XX, a poluição do ar nos grandes centros piorou em consequência processo de industrialização e urbanização, juntamente com o rápido crescimento populacional e do transporte motorizado. Algumas espécies de plantas absorvem os poluentes atmosféricos pelas suas folhas e então, fixa-os em sua matriz, tornando-se assim um biomonitor de poluição nessa área. Assim, a análise foliar dessas espécies de vegetal pode ser usado como monitoramento ambiental. Uma das plantas que tem a habilidade de reter certos elementos químicos do ambiente e pode ser usada como biomonitor é a Nerium oleander L.. Neste estudo utilizou-se folhas de Nerium oleander L. para avaliar os níveis de poluição ambiental em uma sub-região da Região Metropolitana do Rio de Janeiro através da Fluorescência de Raios X (EDXRF). O sistema de EDXRF foi desenvolvido no próprio laboratório e consiste de um sistema portátil de XRF formado por um mini tubo raio X de baixa potência (anodo de Ag e operação em 20 kV/50 μA) e um detector de SiPIN. As amostras de Nerium oleander L. foram coletadas de plantas adultas. As amostras foram coletadas durante as quatros estações do ano (verão, outono, inverno e primavera). Todas as folhas foram coletadas a uma distância superior de 1,5 m em relação ao solo. As amostras foram acondicionadas em sacos plásticos e depois da chegada ao laboratório foram colocados sob refrigeração a 5 C. No laboratório, as amostras foram limpas com um pincel com cerdas macias para retirar a poeira. Depois disso, as amostras foram colocadas na estufa a 60 C por 48 h. Em seguida, as amostras foram pulverizadas (44 μm). Depois desse processo, alíquotas de 500 mg de massa foram prensadas a uma pressão de 2.32×108 por cerca de 15 minutos, afim de se obter pastilhas finas com diâmetro de 2,54 cm e densidade superficial de 100 mg/cm2. Foi possível detectar a concentração de 13 elementos: S, Cl, K, Ca, Mn, Fe, Cu, Zn, Br, Rb, Sr, Ba e Pb. A partir da concentração de cada elemento foram obtidos os mapas de distribuição elementar da área de estudo para cada estação. A análise da correlação de Pearson mostrou que existe uma correlação significativa entre os elementos Fe, Zn, Ba e Pb, entre os elementos Ca e Sr e entre os elementos Cl, K, Rb. A análise do PCA (Análise por Componentes Principais) mostrou que existem dois fatores principais da emissão de poluição ambiental: emissão por ressuspensão do solo (Cl, K, Ca, Mn, Rb e Sr) e emissões veiculares e industriais (Fe, Zn, Ba e Pb). O estudo da poluição ambiental através da técnica de EDXRF utilizando folhas de Nerium oleander L. como biomonitor se mostrou uma técnica de baixo custo e eficiência substancial na determinação da concentração elementar dos poluentes atmosféricos. / Since the early 20th century, the air pollution in the great urban areas has worsened as a result of the industrialization and urbanization processes, jointly with the rapid population growth and the motorized transport. Some plants species absorb the air pollutant atmosphere by the leaves and then fixed them in its matrix, thus becoming a biomonitor of pollution in that area. Thus, the foliar analysis of these vegetal species can be used to environmental monitoring. One of the plants that have the ability to retain certain chemical elements in the environmental and it can be used as a biomonitor is the Nerium oleander L.. In this study were used Nerium oleander L. leaves to measure the environmental pollution levels in a sub-region in the Rio de Janeiro Metropolitan Region-Brazil through the X-ray Fluorescence (EDXRF). The EDXRF system was developed in the own laboratory and consist of a portable XRF system formed by a mini X-ray tube of low power (anode of Ag and operated in 20 kV/50 μA) and a SiPIN detector. The samples of Nerium oleander L. were collected from adult plants. The samples were collected during the year seasons (summer, fall, winter and spring). All the leaves were collected at a distance superior of a 1.5 m relative to the soil. The samples were packed in plastic bags and after the arrival in the Laboratory were placed under refrigeration at 5 C. In the laboratory, the samples were cleaned with a brush with soft bristles to remove dust. After that, the samples were placed in the stove at 60 C for 48 h. Next, the leaves were powdered (325 mesh). After this process, aliquots of 500 mg mass were pressed at a pressure of 2.32×108 Pa for about 15 minutes, order to obtain thin pellets with a diameter of 2.54 cm and superficial density of 100 mg/cm2. It was possible to determinate 13 elements concentration: S, Cl, K, Ca, Mn, Fe, Cu, Zn, Br, Rb, Sr, Ba and Pb. From the concentrations of each element were obtained the elemental distribution maps of the studied area in each season. The Pearson's correlation analysis shows a significant correlation between the elements Fe, Zn, Ba and Pb, between the elements Ca and Sr and between the elements Cl, K and Rb. The PCA (Principal Components Analysis) analysis shows that there is two mainly factors of the environmental pollution emissions: emission through the resuspension of the soil (Cl, K, Ca, Mn, Rb and Sr), vehicular and industrial emission (Fe, Zn, Ba and Pb). The study of the environmental pollution using the Nerium oleander L. leaves as a biomonitor proved an inexpensive technique and substantial efficiency in the determination of elements concentration.
159

Ecologia da comunidade de diatomáceas epilíticas em trecho impactado por psicultura no curso superior do Rio das Antas (São José dos Ausentes, RS)

Schneck, Fabiana January 2007 (has links)
As diatomáceas constituem um dos grupos de algas mais representativos nas comunidades perifíticas, exercem importante papel como produtoras primárias em ambientes lóticos de baixa ordem e são consideradas boas indicadoras ambientais, sendo utilizadas no biomonitoramento de ecossistemas aquáticos. Porém, as informações existentes sobre a estrutura das comunidades de diatomáceas epilíticas em rios brasileiros são ainda muito escassas, especialmente em riachos de altitude. Assim, objetivou-se determinar a estrutura da comunidade de diatomáceas epilíticas em um riacho de altitude no Rio Grande do Sul impactado por atividade de piscicultura. De julho de 2005 a fevereiro de 2006 foram coletadas, mensalmente, amostras de diatomáceas sobre seixos e feitas medições de uma série de variáveis ambientais, em quatro estações amostrais, sendo duas a montante e duas a jusante da piscicultura, em trecho de 3a. ordem do Rio das Antas, município de São José dos Ausentes, a uma altitude de aproximadamente 1000 m. A análise quantitativa das diatomáceas foi realizada com material fixado, sob microscópio invertido, considerando a viabilidade das células, sendo posteriormente preparadas lâminas permanentes para identificação dos táxons. A comunidade de diatomáceas epilíticas esteve representada por 48 táxons e os resultados demonstraram a ocorrência de um gradiente de impacto associado aos efluentes da piscicultura, com significativo incremento nos teores de nutrientes e sólidos totais a jusante. A comunidade de diatomáceas respondeu ao enriquecimento trófico através de uma nítida substituição de espécies características de ambientes oligotróficos por espécies indicadoras de ambientes eutróficos. A Análise de Espécies Indicadoras identificou nove espécies que puderam ser separadas em dois grupos. Gomphoneis rhombica, Navicula angusta e Planothidium frequentissimum indicaram ambientes pouco impactados, com baixa disponibilidade de nutrientes, pouca quantidade de sólidos totais e baixa turbidez. Já Luticola goeppertiana, Melosira varians, Nitzschia palea, Gomphonema parvulum, Navicula cryptotenella e Psammothidium subatomoides indicaram águas eutróficas. Assim, as diatomáceas epilíticas demonstraram ser uma útil ferramenta no biomonitoramento de impactos causados por eutrofização. / Diatoms are one of the most representative groups of algae in periphytic communities, acting as important primary producers in low order streams. They are considered good environmental indicators, being widely used in freshwater ecosystems biomonitoring. However, informations about the ecology and structure of epilithic diatom communities in brazilian streams is still very scarce, especially in altitudinal streams. The aim of this study is to evaluate the structure of epilithic diatom community in an altitudinal stream located in the state of Rio Grande do Sul, Brazil, impacted by fish farm effluents. Antas River is a third order stream at the study sites, and is located at Campos de Cima da Serra, the highest region of Rio Grande do Sul. Epilithic diatoms and physical and chemical variables of the water were sampled monthly, from July 2005 to February 2006, in four sample stations. Two sample stations were located upstream the fish farm and the other two were downstream. Diatoms were counted under an inverted microscope for observing cells viability, and permanent slides were prepared for further identification. Diatom community was represented by 48 taxons and the results had shown a pollution gradient along the stream, with significant increase of nutrients and total solids concentrations downstream the fish farm. Diatom community has answered to the trophic enrichment through a clear change in density and species composition. Typical oligotrophic species were substituted for eutrophic ones. Indicator Species Analysis identified nine indicator species that can be distinguished in two groups. Gomphoneis rhombica, Navicula angusta and Planothidium frequentissimum, indicated environments with less anthropogenic impacts, characterized by low nutrient and total solid concentrations. Yet Luticola goeppertiana, Melosira varians, Nitzschia palea, Gomphonema parvulum, Navicula cryptotenella and Psammothidium subatomoides had indicated eutrophic waters. Thus, epilithic diatoms had demonstrated to be a useful tool for biomonitoring impacts caused by eutrophication.
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Estudo dos processos de remoção de poluentes atmosféricos e utilização de bioindicadores na Região Metropolitana de Porto Alegre, RS

Migliavacca, Daniela Montanari January 2009 (has links)
A precipitação atmosférica é considerada um importante processo de remoção de poluentes da atmosfera. A caracterização química desta matriz ambiental pode indicar a presença de espécies inorgânicas proveniente de fontes naturais e antrópicas de uma determinada região. O presente trabalho foi realizado em três locais da Região Metropolitana de Porto Alegre (RMPA), no Sul do Brasil: Porto Alegre, Canoas e Sapucaia do Sul. Onde o crescimento das atividades urbano-industriais tem provocado um significativo aumento das emissões de poluentes para a atmosfera. A análise da caracterização química da precipitação úmida foi determinada por diferentes técnicas quantitativas: íons maiores por cromatografia iônica, elementos metálicos (Espectrometria de Emissão por Plasma - ICP/AES), razões isotópicas de Pb, Difratometria de Raios-X (DRX) e Microscopia Eletrônica de Varredura (MEV), com sistema EDS (Energy Dispersive Sistem). Além disso, foi realizado também um biomonitoramento com a espécie Lolium multiflorum Lam. Gramineae, somente para 2007, a fim de relacionar estes resultados com os dados dos parâmetros químicos da precipitação úmida da região estudada. Nesta parte do presente estudo foi selecionado um local controle, em Porto Alegre. Os resultados da integração dos dados do biomonitoramento com os dados de precipitação úmida mostraram que os íons Cl-, Na+, SO4 2-, NH4 + e Ca2+ apresentaram as maiores taxas de deposição, o que representou um elevado fator de enriquecimento para os íons Ca2+, K+ e SO4 2-. Os elementos metálicos Zn, Fe e Mn apresentam as maiores taxas de deposição na maioria dos meses estudados. Os parâmetros que avaliaram o biomonitoramento, atividade da enzima nitrato redutase, teor de enxofre e acúmulo de metais na área foliar da espécie Lolium multiflorum, mostraram-se mais significativos nas estações de amostragens Sapucaia e Canoas. A análise de cluster foi aplicada para integrar os resultados do biomonitoramento e da precipitação úmida, indicando a formação de dois agrupamentos distintos: Cluster 1 identificou os meses menos chuvosos e locais de exposição que não apresentaram valores elevados das variáveis analisadas, tanto no biomonitoramento como na precipitação úmida, incluindo a estação Porto Alegre/Controle. Entretanto, o cluster 2 caracterizou-se pela correlação entre os meses que mostraram as maiores taxas de pluviometria, o maior acúmulo de elementos metálicos e o mais elevado teor de enxofre na espécie de L. multiflorum, e as maiores taxas de deposição de elementos metálicos e íons maiores nas amostras de precipitação úmida da região estudada. A precipitação atmosférica de uma determinada região pode indicar alterações em bioindicadores acumulativos, principalmente para elementos metálicos, como a espécie L. multiflorum. Os resultados da composição química da precipitação úmida dos locais estudados, durante o período de 2005 a 2007, apresentaram como íons predominantes NH4 +, SO4 2- e Ca2+. O pH apresentou um valor médio de 5,97 +/- 0,5. Foram identificadas origens naturais e antrópicas na região estudada, através da aplicação de análises estatísticas multivariadas. Observam-se como fontes naturais aerossóis marinhos (Na+, Cl- e Mg2+) e partículas da crosta terrestre (Ca2+ e Mn). E a origem antrópica foi identificada pela presença de NO3 -, SO4 2-, NH4 +, Fe, Cu e Ni, e em menor proporção H+ e F- , proveniente de atividades industriais como refino de petróleo, siderurgia, fertilizantes, termoelétricas e também emissões veiculares. O predomínio da contribuição antrópica proveniente de emissões veiculares e de atividades siderúrgicas, presentes na região estudada, pode ser identificado pelas assinaturas isotópicas de 208Pb/207Pb e 206Pb/207Pb analisadas na precipitação úmida e material particulado suspenso da RMPA. Outra parte importante do presente trabalho foi à aplicação de modelos numéricos no estudo dos processos de remoção de SO4 2- que podem ocorrer dentro e abaixo da nuvem na região estudada. Foram aplicados dois modelos, o BRAMS (Brazilian Regional Atmospheric Modeling System) para simular a estrutura vertical das nuvens e o modelo de remoção B. V. 2 (Below-Cloud Beheng, versão 2) para calcular as concentrações de SO2 e SO4 2- que podem ocorrer na remoção úmida dentro (rainout) e abaixo da nuvem (washout). As concentrações de SO4 2- medidas experimentalmente na precipitação úmida e a concentração de SO2 no ar foram utilizadas como dados na modelagem. Os resultados modelados para a remoção de SO4 2- demostraram uma boa concordância (r=0,73) com os valores observados experimentalmente na precipitação úmida dos locais estudados. E também foi observada uma predominância dos processos de remoção que ocorrem dentro da nuvem como sendo os responsáveis por cerca de 70 a 90% da concentração de SO4 2- encontrada na água de chuva, sendo corroborados por dados encontrados na literatura. / The atmospheric precipitation is considered one of the most important scavenging processes of pollutants from the atmosphere. The chemical characterization of this environmental matrix may indicate the presence of inorganic species from natural and anthropogenic sources in a determined region. This study was conducted in three cities in the Metropolitan Area of Porto Alegre (MAPA), in southern Brazil: Porto Alegre, Canoas and Sapucaia do Sul. The growth of urban-industrial activities in this region has caused a significant increase in emissions of pollutants to the atmosphere. The analysis of the chemical characterization of wet precipitation was determined by different quantitative techniques: major ions by ion chromatography, metallic elements (by Inductively Coupled Plasma - ICP/AES), Pb stable isotope ratio, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), with EDS (Energy Dispersive System). Moreover, a biomonitoring with Lolium multiflorum Lam Gramineae species has been realized for 2007 in order to relate these results to data from chemical parameters of wet precipitation in the region studied. For this part of the study a control site was selected in Porto Alegre. The results of the integration of data from biomonitoring with wet precipitation data showed that the ions Cl-, Na+, SO4 2-, NH4 + and Ca2+ had the highest rates of deposition, which represented a high enrichment factor for the ions Ca2+, K+ and SO4 2-. The metallic elements Zn, Fe and Mn have the highest rates of deposition in most of the months studied. The parameters evaluating the biomonitoring, activity of the enzyme nitrate reductase, sulfur and accumulation of metals in leaf samplers of L. multiflorum, were more significant in the sampling stations Sapucaia and Canoas. The cluster analysis was applied to integrate the results of biomonitoring and wet precipitation, indicating the formation of two distinct groups: Cluster 1 identified the less rainy months and sites of exposure that did not show high values of variables, both in biomonitoring and in wet precipitation, including the station Porto Alegre/Control. However, the cluster 2 was characterized by the correlation between the months that showed the highest rates of rainfall, the largest accumulation of metallic elements and high sulfur content in the species of L. multiflorum, and higher deposition rates of metallic elements and major ions in samples of wet precipitation in the region studied. It was shown that the atmospheric precipitation in a region may indicate changes in accumulative bioindicators, especially for metallic elements, such as species L. multiflorum. The results of the chemical composition of wet precipitation at the studied sites during the period 2005 to 2007 presented as predominant ions NH4 +, SO4 2- and Ca 2+. The pH presented an average of 5.97 ± 0.5. Natural and anthropogenic sources in the studied region were identified by the application of multivariate statistical analysis. As natural sources from marine aerosols observes Na+, Cl- and Mg2+ as well as Ca2+ and Mn for soil of origin respectively. The anthropogenic sources were identified by the presence of NO3 -,SO4 2-, NH4 +, Fe, Cu and Ni and to a lesser extent H+ and F-, from industrial activities as oil refinery, steel production, fertilizers, coal-fired power plants and vehicular emissions. The dominance of the anthropogenic emissions from vehicles and industrial activities, present in the studied region, can be identified by the isotopic signatures of 208Pb/207Pb and 206Pb/207Pb analyzed in wet precipitation and suspended particulate material of the MAPA. Another essential part of this work is characterized by the application of numerical models in the study the scavenging processes of SO4 2- that can occur in-cloud and below-cloud in the region studied. Two models were applied: The BRAMS (Brazilian Regional Atmospheric Modeling System) to simulate cloud vertical structure and model B. V. 2 (Below-Cloud Beheng, version 2) to calculate the concentrations of SO2 and SO4 2- that occur in-cloud and below-cloud in the event of rainfall. The experimentally observed concentrations of SO4 2- in wet precipitation and concentration of SO2 in the air were used as modeling data. The modeled results for the removal of SO4 2- showed a good correlation (r = 0.73) with the experimentally observed values of wet precipitation in the studied sites. There was also a predominance of in-cloud scavenging processes responsible for about 70 to 90% of the concentration of sulfate in rainwater, corroborating data in the literature.

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