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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.
41

Análise da interação entre substâncias húmicas e xenobióticos através de estudos ecotoxicológicos: propostas para a geração de tecnologias de detoxificação aquática / Study of humic substances and xenobiotics interaction using ecotoxicological studies: aquatic detoxification technologies purposes

Domingos Sávio Barbosa 31 October 2008 (has links)
Este estudo teve como objetivo avaliar a interação entre substâncias húmicas e xenobióticos através de estudos ecotoxicológicos. O principal foco foi avaliar a resposta entre diferentes níveis tróficos em organismos aquáticos (fitoplanctônicos, zooplanctônicos, peixes e macroinvertebrados bentônicos) e terrestres (vegetais superiores, insetos e anelídeos) avaliando os efeitos diretos e indiretos das SH e de sua mistura com xenobióticos sobre os organismos. O reconhecido efeito das SH aumentarem ou reduzirem o efeito tóxico de algumas substâncias foi estudado. Os principais pontos para discussão são: a) SH podem reduzir ou estimular o crescimento algal (P. subcapitata); b) A presença de SH podem proteger os organismos contra efeitos tóxicos de metais, no entanto, a presença de Cd/Cu afeta negativamente o crescimento de C. xanthus. d) Em uma análise integrada de processos de remediação solo/água, a presença de SH afetou negativamente ou positivamente os efeitos tóxicos da atrazina em alguns organismos. A significância das SH como tecnologia é discutida. / This study focuses the interaction of humic substances and xenonbiotics, throw ecotixicological studies. The main point was quantify and qualify the ecotoxicological responses of several throphic levels of freshwater (algae, zooplankton, fishes and benthic organisms) and soil organisms (higth plants, insects and annelids) analyzing the direct and indirect effects of humic substances (HS) and their mixture on organisms. The recognized ability of HS on improve or reduce the toxic effect of same substances has been studied. The main points of discussion are: a) humic can be both reduce or stimulate the algal growth (P. subcapitata); b) The presence of HS can be protect aquatic organisms to negative effects of metals. However, the presence of mixture of Cd/Cu affect negatively the growth of C. xanthus; d) In a integrated analysis of remediation process in soil/water microcosm, the presence of HS displayed negative or positive effects on atrazine toxicity for some organisms. The value of humic technology was discussed.
42

Ecological Risk Assessment of a River Water on Agricultural Area in West Java Province, Indonesia and Comparison with Whole Effluent Toxicity Test / インドネシア西ジャワ地方農業地区における河川水の生態リスク評価とWET試験との比較

Diana, Rahayuning Wulan 23 September 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22767号 / 工博第4766号 / 新制||工||1745(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 清水 芳久, 准教授 松井 康人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
43

A Behavioral Model for Detection of Acute Stress in Bivalves

Allen, H. Joel 05 1900 (has links)
A behavioral model for acute responses in bivalves, was developed using time series analysis for use in a real-time biomonitoring unit. Stressed bivalves closed their shell and waited for the stressful conditions to pass. Baseline data showed that group behavior of fifteen bivalves was periodic, however, individuals behaved independently. Group behavior did not change over a period of 20 minutes more than 30 percent, however, following toxic exposures the group behavior changed by more than 30 percent within 20 minutes. Behavior was mathematically modeled using autoregression to compare current and past behavior. A logical alarm applied to the behavior model determined when organisms were stressed. The ability to disseminate data collected in real time via the Internet was demonstrated.
44

Assessment of the effectiveness of public participation in environmental impact assessment: a case study of Matseke filling station development

Rikhotso, Shenen January 2023 (has links)
Thesis (M.Sc. (Geography)) -- University of Limpopo, 2023 / The process of Environmental Impact Assessment (EIA) aims at identifying the significant environmental, social, and economic impacts of a proposed project before a decision is made of whether a project should commence. The Public Participation Process (PPP) should occur throughout all phases of an EIA process and forms an integral part of successful EIAs. It allows for input from stakeholders and subsequently contributes to sustainable development. This process is however often viewed as a “box-ticking” exercise negatively impacting the intended effectiveness thereof. This study therefore aimed to assess the perceived effectiveness of public participation in EIA processes of the Matseke filling station project in the Capricorn District of Limpopo from the perspective of various key stakeholders. The study was descriptive and exploratory in nature and a qualitative research approach was considered pragmatic. Two key informant interviews were undertaken with the environmental assessment practitioner (EAP) and government official that was involved in the EIA processes. Furthermore, a total of 16 Interested and Affected Parties (I&APs) were identified to participate in the study. Different methods of qualitative analyses were used to analyse the objectives of this study. The methods include thematic analysis and descriptive statistics such as percentages and frequencies. The Statistical Package for Social Science (SPSS) version 24.0 software was used to analyse the data. The study findings show that the identified I&APs indicated that they were not involved in project planning and design. It further shows that only one I&AP commented during the process. Education, language, gender and methods of communication were identified as key factors in determining level and effectiveness of public participation processes. The study recommends that potential I&APs need to be educated by EAPs and government officials as to the role they play in ensuring effective public participation
45

Development of an Ecological Risk Assessment Tool for Trace Organic Compounds

Su, Yang 03 September 2015 (has links)
No description available.
46

Propagation of Juvenile Freshwater Mussels (Bivalvia: Unionidae) and Assessment of Habitat Suitability for Restoration of Mussels in the Clinch River, Virginia

Zimmerman, Lora Leigh 07 April 2003 (has links)
Freshwater mussel propagation techniques were tested at the Virginia Department of Game and Inland Fisheries Aquatic Wildlife Conservation Center through a series of three experiments. Experiment 1 tested the suitability of a pond and raceway for rearing juvenile oystermussels (Epioblasma capsaeformis) and wavyrayed lampmussel (Lampsilis fasciola). This experiment was prematurely terminated due to predation on mussels by fathead minnows (Pimephales promelas). Experiment 2 evaluated growth and survival of juvenile rainbow mussels in outdoor troughs and indoor aquaria. There was no significant difference in survival or growth between the two systems. Experiment 3 used troughs similar to those in Experiment 2 to rear E. capsaeformis and L. fasciola under two silt regimes. Survival for Experiment 3 was significantly greater for L. fasciola. The comparison between silt regimes indicated that individuals in the high-silt treatment had better survival than those in the low-silt treatment. The difference between these 2 treatments may be a reflection of increased escapement in the low-silt treatment, which may have resulted from more frequent disturbance during sampling. Growth of L. fasciola was significantly greater than E. capsaeformis, and was greater in the low-silt treatment. A habitat survey of the Clinch River, Virginia was conducted from Blackford, Clinch River Kilometer (CRK) 478 to the Tennessee border, CRK 325. Physical characteristics identified in the survey were combined with water quality and impact source data to develop a habitat suitability index for freshwater mussels within this study reach. Model parameters were indexed and weighted to give a final suitability ranking. Habitat units having the highest overall ranking included: Nash Ford (CRK 449), Artrip (CRK 442), several riffles and runs below Carterton (CRK 417), upstream of Mill Island (CRK 389.5), and Pendleton Island (CRK 365), and Speers Ferry (CRK 333-325). Potential locations for habitat restoration projects and additional monitoring were also identified. / Master of Science
47

Patterns and pathways of lead contamination in mottled ducks (Anas fulvigula) and their habitat

Kearns, Brian Vance January 1900 (has links)
Doctor of Philosophy / Department of Biology / David A. Haukos / Mottled ducks (Anas fulvigula) are dabbling waterfowl species native to coastal wetlands of the Gulf of Mexico of the United States and Mexico. Although closely related to common waterfowl species such as the mallard (A. platyrhynchos) and American black duck (A. rubripes), the mottled duck exhibits unique behavior, mainly in its life history as a non-migratory species. As such, because of population declines caused by predation, habitat destruction, and environmental contaminants, this species requires specialized conservation concerns and species-specific management to protect population numbers. The goal of this study was to assess ongoing effect of observed lead (Pb) contamination and exposure issues in mottled ducks and their habitats, which I achieved by conducting assessments that will provide managers habitat and organism level metrics to detect and mitigate lead in mottled ducks and their environments. My field study was conducted at the Texas Chenier Plain National Wildlife Refuge Complex (TCPC), which was the area of greatest mottled duck density on the Texas Coast. I first created a body condition index to provide managers a tool to monitor population health, and a proxy for lead exposure and avian health without destructively sampling individuals. I then used presence-only maximum entropy (MaxENT) and multivariate statistical modeling procedures in conjunction with mottled duck movement data to elucidate sets of habitat conditions that were conducive to predicting the occurrence of mottled ducks and environmental lead “hot spots”. MaxENT analyses suggested that lead in the top portion of the soil column is similarly related to all environmental variables considered, may be increasingly available after large-scale environmental disturbances. Lack of variation in coarse-scale habitat use between breeding and non-breeding seasons may further point to a food-based exposure pathway for lead as mottled ducks switch from an invertebrate to plant diet, either as a result of changing age classes or normal adult phenology, during the period of increased lead exposure. Using stable isotope ratio analysis, I then tested environmental samples of soil and vegetation as well as mottled duck blood to determine isotopic signatures that were consistent with particular sources of lead deposition (e.g., lead shot pellets, leaded fossil fuel combustion, industrial effluents). Comparisons suggested a great deal of similarity to lead shot reference values in vegetation and blood samples, especially in blood samples with higher concentrations of lead present. Last, I conducted a formal Ecological Risk Assessment (ERA) procedure to quantify the risk to mottled ducks from lead exposure in their current habitat and direct managers towards effective mitigation and habitat management strategies to reduce exposure in the future. One scenario suggested that mottled ducks were at greatest risk from eating an invertebrate-based diet, but lead content values at the TCPC suggest that a plant-based diet may provide a higher lead exposure risk for mottled ducks, depending on true levels of bioavailability in environmental media. Overall, I determined that mottled ducks experience greatest lead exposure risk from lead shot pellets on the TCPC or in nearby habitat, while potentially also experiencing low levels of exposure from several other sources. Additionally, management efforts that focus on plants that do not provide food resources for mottled ducks as a potential environmental sink for lead contamination, such as phytoremediation, may prove effective in reducing the overall lead load from historical activities that likely deposited much of the lead in this ecosystem.
48

Risk assessment of the nonnative Argentine black and white Tegu, Salvator merianae, in South Florida

Unknown Date (has links)
The Argentine black and white tegu, Salvator merianae, is a nonnative species that has invaded parts of Florida. The potential impacts of this species on native Florida wildlife are not yet known. This study looks at the stomach contents of 169 S. merianae captured between 2011 and 2013 in south Florida to infer potential impacts of S. merianae and spatial or seasonal shifts in diet. Analysis of 169 GI tracts showed that S. merianae is an omnivorous, terrestrial forager with a broad dietary range which includes insects, fruits, plants, snails, crayfish, carrion, birds, small mammals, turtles, snakes, lizards, frogs and eggs. S. merianae diet composition varied with capture habitat, the fattest tegus were collected from disturbed/agricultural areas and these samples contained, primarily, gastropods and insects. Tegu dietary habits threaten local endangered and state listed species such as the American crocodile, Crocodylus acutus, and the Cape Sable seaside sparrow, Ammodramus maritimus mirabilis. Dedicated funds and efforts need to be focused on this species to limit its further spread and future impact on native species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection
49

Análise de risco ecológico para o diagnóstico de impactos ambientais em ecossistemas aquáticos continentais tropicais / Ecological risk assessment for the diagnosis of environmental impacts in tropical freshwater ecosystems

Sanchez, André Luís 23 March 2012 (has links)
Os estudos de análise de risco ecológico consistem em avaliar as alterações ecológicas ocasionadas pelas diversas atividades antropogênicas a um determinado sistema, tais como aquelas decorrentes da lixiviação de áreas contaminadas, das emissões de efluentes urbanos, industriais e do runoff de áreas agrícolas, entre outras, por meio da integração das informações físicas, químicas e biológicas. A partir dessa análise, o objetivo geral desse estudo foi avaliar as implicações dos impactos antrópicos relacionados com os diferentes usos e ocupações da bacia hidrográfica do Lobo (municípios de Itirapina e Brotas, estado de São Paulo, Brasil) na dinâmica ecológica dos ecossistemas aquáticos lóticos e lênticos, utilizando para tal finalidade a caracterização limnológica dos corpos hídricos e o reconhecimento dos potenciais impactos existentes, para posterior aplicação de uma análise de risco ecológico, com base nas linhas de evidência química, ecotoxicológica e ecológica. Para tanto, foram realizadas coletas em quatro períodos distintos (chuvoso, seco e intermediários), em 14 estações de amostragem (tributários e reservatório), incluindo variáveis bióticas e abióticas, cujos resultados foram avaliados temporal e sazonalmente, permitindo uma abordagem integrada do sistema. Os resultados obtidos no diagnóstico ambiental indicam que as alterações registradas se relacionam com os usos antrópicos da bacia hidrográfica, incluindo a emissão de efluentes domésticos da cidade de Itirapina (SP) e as fontes difusas associadas ao aporte de sedimentos e agroquímicos utilizados nas diferentes culturas estabelecidas na região. Ao analisar os dados da tríade (químicos, ecotoxicológicos e ecológicos) de forma conjunta e quantitativa, os resultados mostraram que na linha de evidência química os riscos foram maiores no reservatório em relação aos tributários, nos quais os riscos foram considerados como baixo e moderado no período seco, em algumas estações de amostragem. Riscos ecotoxicológicos não foram identificados na maioria dos locais amostrados, porém situação inversa foi registrada para os riscos ecológicos em função da influência das variáveis limnológicas. A integração das linhas de evidência mostra diferença sazonal em relação aos períodos seco e chuvoso, com valores de risco mais elevados no período seco, além da associação do risco com a degradação ambiental de cada sistema avaliado. Assim a partir dos resultados obtidos, verifica-se que os impactos na bacia hidrográfica do Lobo são relevantes, necessitando de medidas emergenciais de recuperação e manejo integrado dos ecossistemas terrestres e aquáticos, promovendo a minimização dos efeitos e recuperação das funções ambientais ou serviços ecossistêmicos em curto, médio e longo prazo. / Ecological risk assessment studies are important to assess environmental changes that have been caused by various anthropogenic activities, such as leaching of contaminated areas, input of domestic and industrial sewage, runoff of agricultural areas and other impacts, which are responsible for physical, chemical and biological alterations. In this context, the aim of this study was to evaluate the impact of the anthropogenic activities developed in the Lobo Hydrographic Basin (Itirapina and Brotas, state of São Paulo, Brazil) on the ecological dynamics of lotic and lentic aquatic ecosystems. To attempt it, limnological studies and the evaluation of the potential impacts were carried out before the subsequent application of an ecological risk analysis, which were based on chemical, ecotoxicological and ecological evidence lines. For this purpose, samples were taken in different periods (rainy, dry and intermediate seasons), in 14 sampling stations (tributaries and reservoir), including biotic and abiotic variables in relation to water and sediment, and the results were analyzed space and seasonally. The results obtained suggest that domestic sewage from Itirapina city (São Paulo State), deforestation and diffuse pollution (associated with the accumulation of sediments and agrochemicals used in different cultures established in the region) were the main impacts in the Lobo watershed. The Triad Analysis (based on chemical, ecotoxicological and ecological measures), in addition of the quantitative results from chemical evidence line, indicated that risks were higher in the reservoir in comparison with the tributaries, where the risks were considered low or moderate in dry season in some sampling stations. Ecotoxicological risks were not identified at most of sampled sites, but the inverse situation was registered for ecological risks due to the influence of limnological variables. Seasonal differences between dry and rainy seasons were observed after the integration of all evidence lines, with higher risk values occurring during dry season, in addition to the risk associated with environmental degradation of each ecosystem. From the results, it is possible to conclude that the activities developed in the Lobo Hydrographic Basin have been responsible for several ecological impacts in this system, beside some alterations promoted by climatological events. Also, to prevent more social, economic and ecological negative consequences, some efforts need to be allocated to minimize the impacts, promoting recovery of the environmental functions and ecosystem services in short, medium and long term.
50

Microbial Aspects of Plant Invasion: An Analysis of Soil Microbial Communities Associated with the Invasive Plant - (Schinus terebinthifolius) Brazilian Pepper Tree Across South-Eastern Florida.

Unknown Date (has links)
The Brazilian pepper tree (BP, Schinus terebinthifolius), introduced to the United States in the 1800s, has since become a category one invasive plant in Florida, aggressively spreading to 3000 km2 of prime habitat. There is a serious dearth of knowledge on whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. This thesis discusses the well-established plant invasion mechanisms of the BP and highlights key emerging mechanisms and gaps in (a) the current understanding of the molecular, below-ground processes of BP invasion and (b) studies on the potential role of microbial interactions in the success of BP invasion already established for other select invasive species, and the intervention of soil metagenomic studies to elucidate plant invasive mechanisms. These poorly studied mechanisms could further explain the aggressive spread and resilience of BP and contribute significantly to the development of effective and sustainable control measures, enabling appropriate strategies for restoring native plants. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

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