• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 57
  • 21
  • 5
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 107
  • 107
  • 107
  • 19
  • 15
  • 15
  • 15
  • 14
  • 13
  • 13
  • 13
  • 12
  • 12
  • 11
  • 9
  • 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

SOURCE, DISTRIBUTION AND FATE OF THE KEY NATURAL FREE AND CONJUGATED ESTROGENS IN THE AQUATIC ENVIRONMENT WITH RISK ASSESSMENT AND MITIGATION STRATEGIES / 水環境に見出される抱合体を含むエストロゲンの起源、分布、挙動に基づくリスク評価と対策

KUMAR, Vimal 23 March 2010 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15364号 / 工博第3243号 / 新制||工||1488(附属図書館) / 27842 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 藤井 滋穂, 教授 米田 稔 / 学位規則第4条第1項該当
42

Perceptions of risk to water environments in the lower Fraser basin, British Columbia

Cavanagh, Nigel Steven 05 1900 (has links)
The following thesis presents the results of a two year study that addressed lay perceptions of the risks to the water resources of the Lower Fraser Basin, British Columbia. Studies of this nature are important because by clarifying public perceptions, risk communication policies as well as land and water resource use plans that accommodate people's concerns can be developed appropriately. The study was based on a written survey that was administered to 183 lay subjects in four communities within the Lower Fraser Basin. Sixteen experts participated in a portion of the survey. Analysis involved the determination of how people perceive distinct human activities in terms of the risk each may pose to the health of aquatic ecosystems. Further analysis compared these perceptions to those of specialists in the aquatic sciences. The thesis is structured as a collection of three papers that examine different aspects of the study. The First paper provides a review of the overall data set, while the remaining two papers address related subsets of the data. One paper reviews perceptions of activities that cause eutrophication problems and the other reviews perceptions of forest industry activities. The results demonstrated that people tend to view risks to water environments in a multi-faceted fashion. Four factors were found to influence people's general perception of risk and the need for regulation of the activities that were perceived to pose the risk. These factors were termed Ecological Impact, Human Benefit, Controllability and Knowledge. Another significant result was the fact that there were often striking differences between the views of the lay sample and those of the expert sample. Some activities were perceived by the lay sample as posing substantial risk while the experts did not view this to be the case. Alternatively, for some activities, the reverse scenario occurred. Accordingly, there were differences in judgements between the two groups as to the degree of regulation that should be imposed on the respective activities. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
43

An overview of environmental development in the game parks of Kenya

Ginter, Carolyn G. 01 January 1996 (has links)
Kenya has one of the oldest and most developed national park and reserve systems among developing nations in Africa. Kenya's ecosystems have felt the impact of tourists, from big game hunters to photographic safaris, for over a century. This project contains the research on which the author intends to base a future book about Kenyan ecoturism for the general public.
44

Within-Generational Disruption of the Stress Response by Fluoxetine and Other Environmental Contaminants in Zebrafish

Nozari, Amin 14 April 2021 (has links)
Selective serotonin reuptake inhibitors (SSRIs), like fluoxetine, are widely used to treat depressive disorders during pregnancy. These antidepressants reach water reservoirs through sewage treatment facilities and expose the aquatic vertebrates, including fish. It has been shown that early-life exposure to fluoxetine could disrupt the normal function of the stress axis by decreasing the level of circulating glucocorticoids in humans, rodents, and teleosts. Our lab recently showed that early life exposure to fluoxetine resulted in transgenerational hyporcortisolism and altered exploratory behaviour in adult male zebrafish and their descendant male adults for at least three generations. In the current study, we used a stress-responsive transgenic zebrafish line (SR4G) that expresses green fluorescence protein (eGFP) under the control of six consecutive glucocorticoid response elements. The effects of developmental exposure to fluoxetine on the transcriptional profiles of genes in the larval head and male adult telencephalon and hypothalamus were analysed using high throughput RNA sequencing. We also assessed the potential of eGFP mRNA to evaluate blunted stress response as an alternative to cortisol immunoassay measurements. The effects of bisphenol A, vinclozolin and fluoxetine were ytested in the SR4G line. Developmental exposure to fluoxetine resulted in a life-long dysregulation of pathways involved in nervous system development, stress response, and lipid metabolism in both larvae and adult zebrafish. Numerous differentially expressed genes in zebrafish are orthologous to genes in Homo sapiens linked the development of the major depressive disorder and epigenetics regulation and include bdnf, trkb, npas4, per1, per2, dnmt3a, adarb1, adaeb2, hdac4, hdac5, hdac8, and atf2. It is suggested that the dysregulation of the primary transcription regulators of circadian rhythm (clocka) and stress response (nr3c1), amongst others, were the potential drivers of the observed life-long effects. Furthermore, we report on a significant positive linear correlation between cortisol levels and eGFP mRNA levels in SR4G transgenic zebrafish larvae (R2> 0.9). Random forest and logistic regression models trained by eGFP mRNA levels both correctly predicted the blunted stress response. The negative predictive value (NPV) for both models was 100%. Models based on the mRNA levels of 11 genes associated with neurogenesis, stress response and depression resulted in a similar 100% NPV. These findings provide evidence for a life-long effect of developmental exposure to fluoxetine. This study also provides a proof-of-concept for an in vivo biomonitoring assay to screen chemicals for their stress-disrupting potential.
45

Ochrana životního prostředí před negativními vlivy humánních léčivých přípravků / Environmental protection against the harmful effects of human medicinal products

Slabá, Kateřina January 2020 (has links)
Environmental protection against the harmful effects of human medicinal products Abstract Medicinal products help humanity, but can they be a risk for it? In recent years, the occurrence of their residues in the environment and their impact on it has been monitored. Their occurrence is found to be widespread. Despite the small concentrations in which they occur, they have been shown to affect, for example, aquatic organisms. The issue of residues of medicinal products in the environment is a current topic, beginning to be also addressed by the European Union. The diploma thesis presents the legal regulations of environmental protection against the adverse effects of human medicinal products; it evaluates their effectiveness and, contains proposals de lege ferenda. First, it outlines the issue and the extent of the occurrence of residues of medicinal products in the environment and their risks for it. Furthermore, the work deals with the legal process of registration of medicinal products regulated by European Union law, within which an environmental risk assessment is created. There are described the shortcomings of the risk assessment procedure, the lack of a link to it that would effectively protect the environment, and the non-disclosure of results, which violates the right to information of the...
46

Improving the transparency and predictability of environmental risk assessments ofpharmaceuticals

Ågerstrand, Marlene January 2010 (has links)
<p>The risk assessment process and the subsequent risk management measures need tobe constantly evaluated, updated and improved. This thesis contributes to that workby considering, and suggesting improvements, regarding aspects like userfriendliness,transparency, accuracy, consistency, data reporting, data selection anddata evaluation.The first paper in this thesis reports from an empirical investigation of themotivations, intentions and expectations underlying the development andimplementation of a voluntary industry owned environmental classification systemfor pharmaceuticals. The results show that the purpose of the classification systemis to provide information, no other risk reduction measures are aimed for.The second paper reports from an evaluation of the accuracy and the consistency ofthe environmental risk assessments conducted within the classification system. Theresults show that the guideline recommendations were not followed in several casesand consequently alternative risk ratios could be determined for six of the 36pharmaceutical substances selected for evaluation in this study. When additionaldata from the open scientific literature was included the risk ratio was altered formore than one-third of the risk assessments. Seven of the 36 substances wereassessed and classified by more than one risk assessor. In two of the seven cases,different producers classified the same substance into different classificationcategories.The third paper addresses the question whether non-standard ecotoxicity data couldbe used systematically in environmental risk assessments of pharmaceuticals. Fourdifferent evaluation methods were used to evaluate nine non-standard studies. Theevaluation result from the different methods varied at surprisingly high rate and theevaluation of the non-standard data concluded that the reliability of the data wasgenerally low.</p> / QC 20100929
47

Element transport in aquatic ecosystems – Modelling general and element-specific mechanisms

Konovalenko, Lena January 2014 (has links)
Radionuclides are widely used in energy production and medical, military and industrial applications. Thus, understanding the behaviour of radionuclides which have been or may be released into ecosystems is important for human and environmental risk assessment. Modelling of radionuclides or their stable element analogues is the only tool that can predict the consequences of accidental release. In this thesis, two dynamic stochastic compartment models for radionuclide/element transfer in a marine coastal ecosystem and a freshwater lake were developed and implemented (Paper I and III), in order to model a hypothetical future release of multiple radionuclides from a nuclear waste disposal site. Element-specific mechanisms such as element uptake via diet and adsorption of elements to organic surfaces were connected to ecosystem carbon models. Element transport in two specific coastal and lake ecosystems were simulated for 26 and 13 elements, respectively (Papers I and III). Using the models, the concentration ratios (CR: the ratio of the element or radionuclide concentration in an organism to the concentration in water) were estimated for different groups of aquatic organisms. The coastal model was also compared with a 3D hydrodynamic spatial model (Paper II) for Cs, Ni and Th, and estimated confidence limits for their modelled CRs. In the absence of site-specific CR data, being able to estimate a range of CR values with such models is an alternative to relying on literature CR values that are not always relevant to the site of interest. Water chemistry was also found to influence uptake of contaminants by aquatic organisms. Empirical inverse relationships were derived between CRs of fish for stable Sr (CRSr) and Cs (CRCs) and water concentrations of their biochemical analogues Ca and K, respectively (Paper IV), illustrating how such relationships could be used in the prediction of more site-specific CRCs and CRSr in fish simply from water chemistry measurements. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>
48

Environmental risk assessment of geothermal springs : a case study of “Eiland” in the Limpopo Province

14 January 2014 (has links)
M.Sc. (Environmental Management) / Geothermal springs exist on all continents of the Earth and are used for a myriad of different applications and uses. The last few years have witnessed a resurgence of interest in these springs due to a proliferation of utilisation of geothermal resources. Despite numerous benefits associated with their use, studies have shown that the water of geothermal springs could contain toxic elements, pathogenic organisms, toxic gases and even elements that are radio-active in nature that may have health impacts on users. The presence of some of these chemicals in the water and air can be traced back to the geological formations through which the thermal waters flow. More than 90 geothermal springs have been identified in South Africa. However, relatively little is known about how South African geothermal springs have been used in the past and how their geochemical composition and land-use around them has changed over time. There is also a scarcity of scientific literature dealing with environmental risk assessment associated with the different uses of geothermal spring water in South Africa. Given this research contextualization, the present study examined the overall water quality and assessed the potential health risks of the geothermal spring and associated waters (hydro spa and overflow pond) of the holiday resort of “Eiland” in the Limpopo Province. The research undertaken for this research project formed part of a bigger Water Research Commission (WRC) research project on geothermal springs in South Africa. Water samples were taken and observations were made of the resort waters during a field trip undertaken during August 2012. Chemical analyses of the samples were performed by the Agricultural Research Council (ARC): Institute for Soil, Climate and Water of South Africa (ISCW). Parameters under investigation included temperature, pH, electrical conductivity, total dissolved solids and various chemical constituents. A comparison of the laboratory results to previous years data and to four domestic water use standards/guidelines was made. These included the EU (1998), SABS (2006), SABS (2011) and the WHO (2011) domestic use water quality standards/guidelines. A risk assessment, based on Aucamp’s (2009) method, was performed for potentially harmful parameters. Overall, the waters of the resort were deemed to be of low risk and therefore not of a health and environmental risk to the users. Although the waters do not satisfy the domestic use water standards, they are suitable for the current recreational purposes of the resort. It is recommended however, that the soil sensitivity be determined for irrigational purposes and toxicology tests be conducted for the fish species inhabiting the overflow pond and small dam in order to determine the possible extent of bioaccumulation. It is recommended that geothermal waters are not used for bottling or for consumption for domestic or therapeutic purposes. In the event of expansion to include such uses a stringent new risk assessment is recommended.
49

Avaliação de risco ambiental: uma aproximação metodológica ao diagnóstico da saúde dos ecossistemas / not available

Pinzón Ramírez, Fernando 13 August 2001 (has links)
Os paradigmas ecológicos atualmente em prática apresentam dificuldades quando aplicados na avaliação, monitoração e gerenciamento dos ecossistemas altamente deteriorados. No entanto uma abordagem baseada na metáfora da saúde ambiental promete vir a ser muito útil. Pela discussão a respeito do conceito de saúde ambiental, o presente ensaio propõe algumas definições bem como um modelo e métodos preliminares de diagnóstico, baseado nos protocolos de Avaliação de Risco Ambiental da agência norte americana. A proposta de avaliação da saúde dos ecossistemas deriva de um nova ciência integradora, a ecotoxicologia, a qual estaria a desenvolver procedimentos para diagnosticar as condições de saúde dos ecossistemas de forma semelhante a como se estima a condição da saúde humana. As principais idéias a respeito de saúde dos ecossistemas estão sendo condensadas em três capítulos principais. Em primeiro lugar é apresentada uma revisão da literatura referente ao conceito de saúde dos ecossistemas e às suas diferentes formas de estimação. Uma vez definidas as bases conceituais, e a modo de exemplo, passa-se a um estudo de caso no qual procura-se estimar alguns aspectos relacionados ao estudo da saúde da Represa de Salto Grande (Americana, SP) mediante a aplicação da metodologia de Avaliação de Risco Ambiental. Finalmente, são apresentadas algumas considerações a respeito do diagnóstico da saúde de reservatórios. / The assessment, monitoring and management of highly deteriorated ecosystems are not easily served for by existing environmental paradigms. The approach to the concept of ecosystem health metaphor is seen to be very useful. This essay proposes some definitions of ecosystem health along with a preliminary diagnostic model and methods based on the USEPA\'s Environmental Risk Assessment framework. The ecosystem health assessment idea derives from the emerging integrative science of ecotoxicology, which would be to seek a procedure about diagnosis of ecosystem health condition similarly to the diagnosis of human health condition. The main ideas about ecosystem health are condensed into three main sections. First, a review of the literature regarding definitions and general approaches of biophysical landscape health is presented. This background stage is followed by a case study, as example, which details how different phases of the USEPA\'s Environmental Risk Assessment framework can be applied to accomplish some aspects of the ecosystem health status from the Salto Grande Reservoir (Americana, SP - Brazil). At the essay\'s conclusion, some remarks regarding the tropical reservoir\'s health diagnosis are presented.
50

The environmental implications of the local-state antinomy in Australia

Wild River, Su, swildriv@cres20.anu.edu.au January 2002 (has links)
An antinomy is a contradiction between a principle and its opposite, where there is a compelling case for accepting both. This thesis adopts the antinomy of local-state government in Australia as its central conceptual theme, describing it with the following defensible, but contradictory principles that:¶ · Australian local governments are statutory agencies of Australia’s state governments, with no power or authority beyond that which is ascribed to them by the states (the outside-in principle); and¶ · Local governments in Australia are independent agencies whose authority and interests transcend their regulatory powers by nature of their attachment to their local area (the inside-out principle).¶ The central conceptual theme of the antinomy of local-state government shapes the overall thesis, as well as providing the focus for its introduction and conclusion. The thesis induces elements of the antinomy and structures much of its discussion around these key issues. It does not try to prove or resolve the antinomy. Instead the thesis uses the concept to explore and develop its second complex theme - the practical and applied experience of Australian local governments (LGs) as they attempt to deliver beneficial environmental outcomes. The great bulk of the substantive work presented in the thesis focuses on descriptions and analyses of LGs’ environmental work and the contexts within which they do it. The thesis contends that the local-state antinomy underpins many problems facing Australian LGs as they attempt to deliver beneficial environmental outcomes. Four research questions are addressed. They are:¶ · How can Australian LG capacity to deliver beneficial environmental outcomes be understood?¶ · Within this capacity, what are the environmental outcomes now being achieved by Australian LGs?¶ · How can Australian local government extend its capacity to deliver beneficial environmental outcomes? And¶ · What are the implications of the local-state antinomy on Australian LG capacity to deliver beneficial environmental outcomes?¶ This thesis reviews literature on Australian LG, LG environmental work, and the methods that are appropriate in investigating these questions. The overall thesis uses scientific, grounded theory and action research methods and draws on ideas from symbolic interactionism. Parts of the thesis also use environmental risk assessment, gap analysis techniques, case study and comparative analysis. The goal of generating grounded theories led to a strong focus on the development and exploration of analytical categories and the relationships between them. One such category summarises the relationship between LG and state government (SG), whereby LGs are identified as the inside sphere of government, while the SG is one of several outside spheres. Environmental efforts that impact between the spheres are described in relation to their source and impact, using this terminology, so that inside-out initiatives are driven by LGs but impact more broadly, and outside-in initiatives are driven by states but impact on local areas.¶ Two extensive studies are presented, each stemming primarily from one side of the local-state antinomy. The first is a quantitative, statewide study of local (and state) government implementation of the Queensland Environmental Protection Act. That process is considered a predominantly outside-in environmental initiative, in that LG interest and authority for that work stem directly from a SG statute. For simplicity, this is referred to as an outside-in study. That study involved the development and application of the Comparative Environmental Risk Assessment Method, that enabled the assessment of the environmental and other outcomes from the Queensland legislation.¶ The outside-in study is complimented by comparative case studies that mostly reflect inside-out environmental initiatives as they are defined and described by LGs. Again, this required the development of innovative research methods, specifically a comparative case study method. 34 case studies gathered from different types of LGs across Australia are presented, each representing an attempt by LG to deliver beneficial environmental outcomes.¶ In answer to the research questions, LG capacity to deliver environmental outcomes can be understood when the antinomy is examined through the research methods and analytical categories developed and presented here. LGs are delivering significant beneficial environmental outcomes, both as agents of SGs and through their own initiatives. Improving LG capacity to deliver environmental outcomes primarily requires a respect for LG perspectives, and for LG priorities, which inherently include a focus on their own local areas. State governments can build effective partnerships between the spheres and enhance LG environmental capacity by recognising and supporting LG’s own priorities, while assisting their engagement with broader strategic objectives.

Page generated in 0.1278 seconds