23 resultados para Aquatic invertebrates


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Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous priority pollutants that tend to be trapped in aquatic sediments due to their high hydrophobicity. Nonetheless, the differential toxicological effects and mechanisms between the various classes of PAHs and their mixtures, as they invariably occur in the environment, are scarcely known, especially under ecologically-relevant scenarios. This thesis aimed at establishing a bridge between the study of mechanistic pathways and environmental monitoring of carcinogenic and non-carcinogenic PAHs, by introducing ecological-relevance in the research with model PAHs. A first bioassay conducted in situ with the mussel Mytilus edulis demonstrated that, dredging operations in harbours increase PAH bioavailability, eliciting genotoxicity, and showed that established environmental guidelines underestimate risk. Subsequent ex situ bioassays were performed with the carcinogenic benzo[b]fluoranthene (B[b]F) and non-carcinogenic phenantrene (Phe), selected following preceding results, and revealed that low-moderate concentrations of these PAHs in spiked sediments induce genotoxic effects to the clam Ruditapes decussatus, therefore contradicting the general notion that bivalves are less sensitive to PAHs than vertebrates due to inefficient bioactivation. Also, it was demonstrated that passive samplers permit inferring on PAH bioavailability but not on bioaccumulation or toxic effects. On the other hand, sea basses (Dicentrarchus labrax), yielded a complex pattern of effects and responses, relatively to genotoxicity, oxidative stress and production of specific metabolites, especially when exposed to mixtures of the PAHs which led to additive, if not synergistic, effects. It was shown that Phe may elicit significant genotoxicity especially in presence of B[b]F, even though the low, albeit realistic, exposure concentrations diluted dose- and time-independent relationships. The present work demonstrated that environmental quality guidelines underestimate the effects of PAHs in realistic scenarios and showed that the significant genotoxic and histopathological effects caused by mixed PAHs may not be reflected by oxidative stress- or CYP-related biomarkers. Besides important findings on the metabolism of PAH mixtures, the work calls for the need to re-evaluate the criteria for assessing risk and for the disclosure of more efficient indicators of toxicological hazard.

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Estuaries are perhaps the most threatened environments in the coastal fringe; the coincidence of high natural value and attractiveness for human use has led to conflicts between conservation and development. These conflicts occur in the Sado Estuary since its location is near the industrialised zone of Peninsula of Setúbal and at the same time, a great part of the Estuary is classified as a Natural Reserve due to its high biodiversity. These facts led us to the need of implementing a model of environmental management and quality assessment, based on methodologies that enable the assessment of the Sado Estuary quality and evaluation of the human pressures in the estuary. These methodologies are based on indicators that can better depict the state of the environment and not necessarily all that could be measured or analysed. Sediments have always been considered as an important temporary source of some compounds or a sink for other type of materials or an interface where a great diversity of biogeochemical transformations occur. For all this they are of great importance in the formulation of coastal management system. Many authors have been using sediments to monitor aquatic contamination, showing great advantages when compared to the sampling of the traditional water column. The main objective of this thesis was to develop an estuary environmental management framework applied to Sado Estuary using the DPSIR Model (EMMSado), including data collection, data processing and data analysis. The support infrastructure of EMMSado were a set of spatially contiguous and homogeneous regions of sediment structure (management units). The environmental quality of the estuary was assessed through the sediment quality assessment and integrated in a preliminary stage with the human pressure for development. Besides the earlier explained advantages, studying the quality of the estuary mainly based on the indicators and indexes of the sediment compartment also turns this methodology easier, faster and human and financial resource saving. These are essential factors to an efficient environmental management of coastal areas. Data management, visualization, processing and analysis was obtained through the combined use of indicators and indices, sampling optimization techniques, Geographical Information Systems, remote sensing, statistics for spatial data, Global Positioning Systems and best expert judgments. As a global conclusion, from the nineteen management units delineated and analyzed three showed no ecological risk (18.5 % of the study area). The areas of more concern (5.6 % of the study area) are located in the North Channel and are under strong human pressure mainly due to industrial activities. These areas have also low hydrodynamics and are, thus associated with high levels of deposition. In particular the areas near Lisnave and Eurominas industries can also accumulate the contamination coming from Águas de Moura Channel, since particles coming from that channel can settle down in that area due to residual flow. In these areas the contaminants of concern, from those analyzed, are the heavy metals and metalloids (Cd, Cu, Zn and As exceeded the PEL guidelines) and the pesticides BHC isomers, heptachlor, isodrin, DDT and metabolits, endosulfan and endrin. In the remain management units (76 % of the study area) there is a moderate impact potential of occurrence of adverse ecological effects and in some of these areas no stress agents could be identified. This emphasizes the need for further research, since unmeasured chemicals may be causing or contributing to these adverse effects. Special attention must be taken to the units with moderate impact potential of occurrence of adverse ecological effects, located inside the natural reserve. Non-point source pollution coming from agriculture and aquaculture activities also seem to contribute with important pollution load into the estuary entering from Águas de Moura Channel. This pressure is expressed in a moderate impact potential for ecological risk existent in the areas near the entrance of this Channel. Pressures may also came from Alcácer Channel although they were not quantified in this study. The management framework presented here, including all the methodological tools may be applied and tested in other estuarine ecosystems, which will also allow a comparison between estuarine ecosystems in other parts of the globe.

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The lignite-clays of Póvoa de Santarém dated as Upper «Vindobonian» (mammalian zone MN6), fielded abundant remains of animals and plants (spores, pollens, seeds, etc.). The forms identified are indicative of several environments. Plants, either aquatic or belonging to swampy areas are predominant (Nuphar sp., Sparganium sp., Stratiotes kaltennordheimensis, cf. Ranunculus sp.). There are also remains of plants characteristiques of a humid rather than a swampy soil such as Polypodiaceae, Myrica ceriferiformis, Toddalia maii, Spirematospermum wetzeleri. The genera Vitis and Ephedra, although rare, point fowards the existence of drier regions in the neighbourhood. The presence of polens such as Picea indicate the presence at some distance less warm upland forest areas.

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The lignite-clays of Póvoa de Santarém dated as Upper «Vindobonian» (mammalian zone MN6), fielded abundant remains of animals and plants (spores, pollens, seeds, etc.). The forms identified are indicative of several environments. Plants, either aquatic or belonging to swampy areas are predominant (Nuphar sp., Sparganium sp., Stratiotes kaltennordheimensis, cf. Ranunculus sp.). There are also remains of plants characteristiques of a humid rather than a swampy soil such as Polypodiaceae, Myrica ceriferiformis, Toddalia maii, Spirematospermum wetzeleri. The genera Vitis and Ephedra, although rare, point fowards the existence of drier regions in the neighbourhood. The presence of polens such as Picea indicate the presence at some distance less warm upland forest areas.

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Aquatic Toxicology 63 (2003) 307-318

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Based upon the depositional sequences in the Guadalquivir basin and the bio-events defined (foraminifera and nanoplancton) we present the synthesis of the paleontological results in correlation with the Neogene of Algarve (Portugal). We present the most representative outcrops for micropaleonlologic results, as well as paleoenvironmental correlations between Algarve and the Guadalquivir basin.

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The sub-fossil fauna from the Late Quaternary marine deposits of Santa Maria is made of more than 50 species of gastropods and bivalves, 19 of them collected recently and for the first time in the northern coast of the island (Lagoinhas Bay). The sub-fossil shells are found in deposits of beach sands, situated 2-3 meters above the present low tide. The carbonated sands from the basal part of the succession yield an autochthonous association of borers dominated by the bivalve Myoforceps aristata (Dillwin, 1817). Upwards, the marine sands contain concentrations of beach drift shells, including well-preserved supratidal and intertidal gastropods, among them a large number of Rissoidae. The bivalve fauna is dominated by disarticulated valves of Ervilia castanea (Montagu, 1803), a small infaunal coloniser of mobile sandy substrates. The composition of the fauna is made essentially of West European species, many of them common to the West Coast of Portugal. However, a few "warm guests" with West African or Caribbean affinities were also found, suggesting a close relation with some of the "Tyrrhenian" warm associations found in the Western Mediterranean.

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Neogene marine mammals are still incompletely known in Portugal. However, a general overview of the geographic and stratigraphic distribution of marine mammal localities in the Miocene of Portugal is already possible. An attempt of correlation between the trends shown by these distributions and the horizontal and vertical environmental shifts is presented. In general, sirenians occur in deposits representing shallow, warm, low energy aquatic environments; while cetaceans are more frequent in more open, deep and temperate marine environments.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, perfil de Engenharia Ecológica

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Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente

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RESUMO: A osteoartrose do joelho é uma condição clínica cuja prevalência tem aumentado nos últimos anos na população idosa. Trata-se de uma condição que pode ser bastante incapacitante para o idoso, gerando um forte impacto social e económico. O exercício aquático tem sido identificado como um factor de promoção da melhoria do quadro clínico nesta população, mas a sua efectividade não está, ainda, determinada. Objectivo: investigar a efectividade, a curto e médio prazo, de um programa de exercício aquático, realizado em grupo, com a duração de 8 semanas, na amplitude articular, dor e rigidez do joelho, e na função física e qualidade de vida, em idosos com osteoartrose do joelho. Metodologia: Recorreu-se a um estudo quase-experimental, double-blind, controlado, sem aleatorização, cuja amostra, constituída por 43 sujeitos, foi selecionada por conveniência. Os sujeitos do grupo experimental (n=22) foram submetidos ao programa de exercício aquático e os do grupo de controlo (n=21) foram submetidos ao programa de exercício no solo. Ambos os programas foram definidos de acordo com as recomendações internacionais para a prática de exercício físico em idosos com osteoartrose (Arthritis Foundation, 2009a, 2009b). Todo o grupo foi avaliado no início do programa, no final do mesmo (8 semanas) e após 6 semanas de follow-up, nos seguintes indicadores: amplitude articular do joelho (através do goniómetro), dor, rigidez, função e qualidade de vida (através do KOOS). Resultados: A amostra deste estudo foi constituída por sujeitos maioritariamente do género feminino (76,7%), com uma média de 72,7 anos (DP=5,49). O programa de exercício aquático implementado demonstrou um aumento da amplitude articular passiva de flexão (p<0,0001) e extensão (p=0,016) do joelho, uma diminuição da dor e da rigidez articular (p<0,0001), um aumento da função nas AVD’s (p<0,0001) e no desporto/lazer (p=0,031), e ainda, um aumento da qualidade de vida (p<0,0001). Contudo, apenas os níveis de amplitude articular passiva de extensão do joelho (p=0,083) e de função no desporto/lazer (p=0,244) se mantiveram ao longo das seis semanas de follow-up. Conclusões: Apesar de algumas limitações, considera-se que este estudo é de grande importância para a comunidade científica e para os fisioterapeutas preocupados com a crescente prevalência da osteoartrose e dos custos associados. O exercício aquático parece ser uma estratégia importante na melhoria do estado de saúde dos idosos com osteoartrose do joelho.----------------- ABSTRACT: The osteoarthritis of the knee is a clinical condition that has been increasing among the elderly population over the past few years. It’s a condition that can be fairly disabling to the elderly individual, and which generates a strong social and economic impact. Aquatic exercise has been named as a promotional factor in the improvement of the clinical picture in this population, but its effectiveness is yet to be determined. Objective: To investigate the effectiveness, in a short and medium term, of an aquatic exercise program undertaken by a group over eight weeks, in the joint amplitude, pain and stiffness of the knee, and in the physical function and quality of life in elderly people who suffer from knee osteoarthritis. Methodology: was used a double-blind, quasi-experimental study with no randomization and its 43 subjects were selected as a matter of convenience. The subjects of the experimental group (n=22) were subjected to an aquatic exercise program and those of the control group (n=21) were subjected to a land-based exercise program. Both programs have followed international recommendations on the practice of physical exercise in elderly people who suffer from osteoarthritis (Arthritis Foundation, 2009a, 2009b). The entire group was evaluated in the beginning and at the end of the program (8 weeks later), and after a 6 week follow-up, in these parameters: knee range of motion (through a goniometer), pain, stiffness, function and quality of life (through KOOS). Results: This sample was predominantly female (76,7%) with a mean age of 72,7 years (SD=5,49). Aquatic exercise resulted in increase of passive joint flexion (p<0,0001) and knee extension (p=0,016), in the decline of pain and stiffness (p<0,0001), in the increase of function in the ADLs (p<0,0001). However, only the knee extension amplitude (p=0,083) and the function in sports/leisure (p=0,244) were kept through the six-week follow-up. Conclusions: Despite some limitations, this study is of great importance to the community and to the physiotherapists concerned with the growing prevalence of osteoarthritis and the associated costs. Aquatic exercise appears to be an important strategy in the improvement of the health condition of patients who suffer from knee osteoarthritis.

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RESUMO - A legionella em meio hospitalar tem sido alvo de preocupação e de várias discussões, sendo esta uma bactéria patogénica que coloniza vários tipos de ambientes aquáticos (naturais e artificiais). Estas bactérias têm a particularidade de se desenvolver em meio aquático mas a infeção apenas é transmitida através de aerossóis de água contaminada, ou seja, por via aérea. Não se transmitindo de pessoa para pessoa. Pelas suas características os sistemas de arrefecimento de ar, nomeadamente as torres de arrefecimento, condensadores evaporativos, humidificadores e sistemas de ar condicionado, são fontes importantes de disseminação da legionella. Assim surge a necessidade da existência de programas de prevenção, que deverão ter em conta uma adequada manutenção, limpeza e desinfeção. Dada a quantidade de frequentadores assim como da especificidade dos mesmos, em meio hospitalar é particularmente importante a eficácia destes sistemas. Ou seja, os sistemas de arrefecimento em hospitais devem, para além de garantir o conforto térmico, ser responsáveis por manter a qualidade do ar e reduzir os riscos existentes a ele associados. O presente estudo pretende conhecer a verdadeira eficácia dos programas de manutenção e vigilância da Legionella, apenas nos sistemas de arrefecimento. Trata-se então de um estudo exploratório, descritivo recolha desta informação in-loco dos sistemas em estudo, de X hospitais da cidade de Lisboa. Na metodologia serão utilizadas grelhas de observação e resultados de colheita de água dos locais de maior risco. A realização deste estudo visa obter um retrato do panorama existente e contribuir para o início de novos estudos epidemiológicos.

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Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente

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Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente