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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.
1

Lidský biomonitoring: omezení a možnosti / Human biomonitoring - limitations and opportunities

Figenschou, Kristian January 2010 (has links)
Human biomonitoring aims to measure the amount of certain substances in all aspects of the environment, how much of this that reach humans and in what way, and finally how this affects our health. In all aspects of this process lays challenges that must be overcome. When measuring substances in the environment, one must make sure that one is measuring the biomarker which gives the most precise results according to what one seeks to find. Dependent on the biomarker in question, multiple factors can potentially affect the measurements. When the most suitable biomarker has been found, one must make sure that all possible sources are located and taken into consideration, in order to provide a sufficient exposure assessment. The next challenge is to gather accurate epidemiologic data, and link this to the exposure in question, and make a reliable risk assessment. As the examples in this paper highlights, within each step are challenges, and possible limitations. For most substances, there are data gaps and incomplete understanding. There is now much work done globally, on how to further improve the process. Based on today's experiences and knowledge, new guidelines are put down. In Europe there was recently launched a program, that will coordinate the cooperation between the member states. Though it is already a...
2

Biologický monitoring - jeho možnosti a omezení / Human biomonitoring - opportunities and limitations

Weissová, Iveta January 2010 (has links)
Human biomonitoring is a term for colleting and evaluating data concerning the pollution of environment and its influence on human body. In the CR it is being conducted since 1994 and its main aim is to protect people's health. The most commonly observed pollutants are heavy metals, PCBs, dioxins, chlorinated pesticides and many others. These pollutants find their way to the environment mainly due to people's industrial and agricultural activities. Smoking is still a current issue that needs to be addressed and it is an activity (voluntarily or in case of passive smoking involuntarily practiced) that causes health damage. Due to human biomonitoring, or more precisely due to principles which are now its foundation, many shortcomings of former industrial activities were discovered. Among others, it leads to understanding "Itai-itai" disease and discovering the cause of events in Japanese bay "Minamata". Today, the industrial (but also other) activities worldwide are at a high level of development. Many chemicals are being used and the environment is still being threatened. Based on those facts it is necessary to continually monitor the presence of toxic (or potentially toxic) substances in the environment and to put forth an extra effort to prevent exposure to these substances. Human biomonitoring is also...
3

USE OF IN-SITU FISH POPULATIONS FOR BIOMONITORING POLYCHLORINATED BIPHENYL AND METAL POLLUTION IN MODERATELY IMPACTED FRESHWATER STREAMS

Price, David John 01 January 2007 (has links)
Water, sediments, floodplain soils, and fish from Big and Little Bayou creeks were assessed for polychlorinated biphenyls (PCBs) and metals in 1987-2005. The streams were impacted by effluents from the Paducah Gaseous Diffusion Plant (PGDP). PCBs were rarely detected in water samples. Aroclor 1248 detections in sediments and floodplains were sporadic, but 1254 and 1260 were consistent. Seasonal variations were only observed for Aroclor 1248. Detection of PCBs in floodplains indicated recent influx of contaminated sediments. Species-specific PCB residues patterns were studied for Lepomis cyanellus, L. megalotis, L. macrochirus, and Campostoma anomalum. Highest PCB concentrations were found in stoneroller minnows. PCBs decreased over time in sunfish species, but retained a baseline level. No relationships were found between sunfish age and PCB concentrations. At low PCB levels, green sunfish body burden (BB) did not correlate with lipid content. A certain PCB concentration must be exceeded before PCB BB correlates with lipid content. Stream flows differed by season, and fish PCB BB differed by season, but stream flow did not correlate with fish BB. Congener groups corresponded to Aroclor concentrations. Higher chlorinated biphenyls peaked in the spring for sport fish. PCBs remobilized in the spring resulted in higher summer BB for the stoneroller minnows, whereas sunfish eliminated PCBs by summer. This variability was due to the sunfishs ability to regulate PCBs. Metal concentrations did not display the seasonal variability evident in the PCB data. Water metals may have peaked during storm events and decreased rapidly. Water Pb increased with time, but the source could not determined. Zinc in Little Bayou creek likely originated from the PGDP. Except for Cu and Zn, stoneroller minnow metal BB decreased with time. Metal BB were used to determine bioavailable fractions. Less than half of the water column Cd, Cr, Fe, and Pb in impacted areas were bioavailable to stoneroller minnows, whereas 59% of Ag, 73% of Cu, and 64% of Zn were bioavailable. Cumulative criterion units were calculated to determine additive metal impacts, and proved useful in locating sectors with possible ecological impact. In-situ monitors proved valuable in studying PCB and metal behavior under real-world conditions.
4

Abandoned Mid-Canada Radar Line Site 500 in the Western Hudson Bay region of sub-Arctic, Canada: A source of organochlorines for the people of Weenusk First Nation?

Bertrand, John 22 May 2008 (has links)
Interest in the presence of environmental contaminants in the Canadian arctic and sub-arctic arises in part over concerns that Aboriginal people residing in these regions continue to rely on subsistence harvesting. Organochlorines (OCs) are a type of persistent organic pollutant (POP) that have a unique chlorine-carbon bond; this bond facilitates their unprecedented environmental longevity, lipophilicity and hydrophobic nature. OCs have been found in both the biotic and non-biotic compartments of northern ecosystems. This study examined patterns of differences with respect to body burden of organochlorines (lipid-adjusted) between the residents of the Ontario First Nations of Fort Albany (the site of MCRL Site 050), Kashechewan (no radar site), and Peawanuck (the site of MCRL 500) to assess whether geo-proximity to abandoned radar sites influenced organochlorine body burden with respect to the people of Fort Albany and Peawanuck. Correspondence analysis (CA-1) revealed people from Fort Albany had relatively higher pesticide concentrations (β-HCH and DDT, but not Mirex) and relatively lower CB (156 and 170) body burdens when compared to participants from Kashechewan and Peawanuck. CA- 2 revealed Peawanuck residents had relatively higher concentrations of CB180, DDE and hexachlorobenzene and relatively lower levels of DDT and mirex compared to participants from Kashechewan and Fort Albany. Results are suggestive but not conclusive that MCRL Site 500 may have influenced body burdens of Peawanuck residents.
5

Abandoned Mid-Canada Radar Line Site 500 in the Western Hudson Bay region of sub-Arctic, Canada: A source of organochlorines for the people of Weenusk First Nation?

Bertrand, John 22 May 2008 (has links)
Interest in the presence of environmental contaminants in the Canadian arctic and sub-arctic arises in part over concerns that Aboriginal people residing in these regions continue to rely on subsistence harvesting. Organochlorines (OCs) are a type of persistent organic pollutant (POP) that have a unique chlorine-carbon bond; this bond facilitates their unprecedented environmental longevity, lipophilicity and hydrophobic nature. OCs have been found in both the biotic and non-biotic compartments of northern ecosystems. This study examined patterns of differences with respect to body burden of organochlorines (lipid-adjusted) between the residents of the Ontario First Nations of Fort Albany (the site of MCRL Site 050), Kashechewan (no radar site), and Peawanuck (the site of MCRL 500) to assess whether geo-proximity to abandoned radar sites influenced organochlorine body burden with respect to the people of Fort Albany and Peawanuck. Correspondence analysis (CA-1) revealed people from Fort Albany had relatively higher pesticide concentrations (β-HCH and DDT, but not Mirex) and relatively lower CB (156 and 170) body burdens when compared to participants from Kashechewan and Peawanuck. CA- 2 revealed Peawanuck residents had relatively higher concentrations of CB180, DDE and hexachlorobenzene and relatively lower levels of DDT and mirex compared to participants from Kashechewan and Fort Albany. Results are suggestive but not conclusive that MCRL Site 500 may have influenced body burdens of Peawanuck residents.
6

Zastoupení kompenzačních cvičení v RTC běžců na lyžích / Compensation of body burden in ATC for cross-country skiing runners in relation to their locomotor system

Suchánková, Barbora January 2014 (has links)
Diploma thesis aims to explore the representation of compensation methods and tools in ATC with representatives of Slovakia in cross - country skiing. Then obtain data on the state of theirs motor system especially the shortened muscle groups. After processing this data to compare them and create a design of supplement the compensation an individual plan. Key words: body burden, compensation, annual training cycle,locomotor system, shortened muscle groups, cross country skiing
7

THE UPTAKE AND EFFECTS OF POLY- AND PERFLUOROALKYL SUBSTANCES ON LARVAL AND JUVENILE AMPHIBIANS

Sarah A. Vaughn (5930915) 17 January 2019 (has links)
Poly- and perfluoroalkyl substances (PFAS) are ubiquitous contaminants across the globe, can bioaccumulate in aquatic taxa, and potentially biomagnify in food webs. Consequently, research examining the influence of PFAS on wildlife is warranted. Amphibians are sensitive to contaminants such as PFAS because of their porous skin and associations with aquatic habitats where contaminants accumulate. Because PFAS tend to bioaccumulate and can adversely affect the endocrine system, there is a need to examine uptake rates to inform ecotoxicology studies, as well as a need to examine sublethal effects. To address these knowledge gaps I conducted two experiments. First, I exposed larval northern leopard frogs (<i>Rana pipiens</i>), American toads (<i>Anaxyrus americanus</i>), and eastern tiger salamanders (<i>Ambystoma tigrinum</i>) to PFAS chemicals perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) at concentrations of 10 or 1000 ppb for 10 days and sampled them every 48 hours during the exposure period. In the next experiment, I examined the effects of PFAS exposure via contaminated substrate on the survival and growth of post metamorphic amphibians of the same species. I found that, for all species, body burdens often reached steady state within 48 to 96 h of exposure. Steady-state body burdens of PFOA ranged from 3,819–16,481 ng/g dry weight among treatments and species (corresponding BCFs of 0.5 to 2.5), while PFOS body burdens ranged from 6,955–489,958 ng/g dry weight (corresponding BCFs of 47–259) among treatments and species. These data suggest that steady state is rapidly reached in larval amphibians exposed to PFAS, particularly regarding PFOS. This reflects a high potential for trophic transfer of PFAS within food webs because amphibians are often low in trophic position and are important prey for many aquatic and terrestrial species. In post-metamorphic amphibians, there was no influence of PFAS on survival or mass. However, significant effects on snout-vent length were observed in all species, and body condition differences were observed for two of my species. I found that all leopard frogs increased in scaled mass index (SMI) when exposed to a PFAS treatment, indicating an increased body condition. Toads exhibited a more variable SMI pattern across treatments, with no outstanding trends, and tiger salamanders did not differ significantly across treatments. These data suggest that sublethal effects vary greatly depending on the species, possibly due to life history traits. Future research examining biomagnification potential is warranted to determine the influence of PFAS on food webs. Additionally, there is a need to determine the physiological mechanisms underlying the observed effects of PFAS exposure.<br>
8

Inverted Quarantine: Individual Response to Collective Fear

Moncure, Katherine Parker 16 June 2016 (has links)
No description available.
9

"It Doesn't Need to be Industrial Strength": An Analysis of Women's Adoption of a Chemical-Free Lifestyle

Vidug, Kristina 23 December 2011 (has links)
This thesis seeks to uncover women’s concerns about chemicals in the household, and, more specifically, in cleaning products. The research is based on semi-structured interviews with women who are primarily responsible for household cleaning and who consciously avoid conventional cleaning products. From a sociological standpoint, the topic remains unstudied. The women were critical of greenwashing and the institutions responsible for chemical regulation. Further, the women’s chemical-free lifestyle defied conventional definitions of activism. Sociological theories of risk are used to help understand women’s avoidance of chemicals. It was found that tenets of the precautionary principle were reflected in their reasoning for avoiding chemicals. Recent biomonitoring and body burden studies have influenced women’s knowledge of chemical risk and their decision to avoid them. The thesis demonstrates that risk-management, in this context, has become an individualized pursuit reflective of the neo-liberal ideology informing chemical regulation. / Canadian Institutes of Health Research

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