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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.
11

Human exposure to persistent organic pollutants : Illustrated by four case studies in Europe

Weiss, Jana January 2006 (has links)
<p>An extensive use of chemicals in countless consumer products has resulted in human exposure to several persistent organic pollutants (POPs). Sufficient knowledge about their chemical composition properties and environmental faith is required, to be able to proper risk assess and regulate the substances. Significant data gaps exist regarding knowledge of actual exposure to humans and toxicological effect data.</p><p>The objective of this thesis was to add human exposure data of a few POPs from four case studies. The analytes discussed in this thesis are polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD).</p><p>Three European populations were studied. Milk was analysed from a group of women, who were accidentally exposed to high levels of 2,3,7,8-TetraCDD (TCDD) in Seveso, 1976. Still today, twice as high TCDD levels were recorded in the milk, compared to background concentrations. Serum was analysed from mothers and their infants from The Netherlands. Cord serum contained equal amounts of POPs as in mother’s blood, indicating non-hindered placenta transfer. Serum analysed from Swedish men and women with a high fish intake had elevated PCB and PCB metabolite (OH-PCB) levels. Additionally, butter was collected worldwide and shown to be a suitable matrix for dairy product survey of POPs.</p><p>The exposure levels in the four papers were compared to recently reported exposure levels in Europe. It is indicated in the thesis that the PCDDs/PCDFs and PCBs toxic equivalency (TEQ) levels are of concern, i.e. the ratio between threshold levels for adverse health effects and TEQ exposure levels is lower than requested margin of safety. Average levels of PBDE/HBCDD in the European population are estimated to be of no concern today, but for individuals with intakes at the 95th percentile are the current margins of safety small.</p>
12

Human exposure to persistent organic pollutants : Illustrated by four case studies in Europe

Weiss, Jana January 2006 (has links)
An extensive use of chemicals in countless consumer products has resulted in human exposure to several persistent organic pollutants (POPs). Sufficient knowledge about their chemical composition properties and environmental faith is required, to be able to proper risk assess and regulate the substances. Significant data gaps exist regarding knowledge of actual exposure to humans and toxicological effect data. The objective of this thesis was to add human exposure data of a few POPs from four case studies. The analytes discussed in this thesis are polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD). Three European populations were studied. Milk was analysed from a group of women, who were accidentally exposed to high levels of 2,3,7,8-TetraCDD (TCDD) in Seveso, 1976. Still today, twice as high TCDD levels were recorded in the milk, compared to background concentrations. Serum was analysed from mothers and their infants from The Netherlands. Cord serum contained equal amounts of POPs as in mother’s blood, indicating non-hindered placenta transfer. Serum analysed from Swedish men and women with a high fish intake had elevated PCB and PCB metabolite (OH-PCB) levels. Additionally, butter was collected worldwide and shown to be a suitable matrix for dairy product survey of POPs. The exposure levels in the four papers were compared to recently reported exposure levels in Europe. It is indicated in the thesis that the PCDDs/PCDFs and PCBs toxic equivalency (TEQ) levels are of concern, i.e. the ratio between threshold levels for adverse health effects and TEQ exposure levels is lower than requested margin of safety. Average levels of PBDE/HBCDD in the European population are estimated to be of no concern today, but for individuals with intakes at the 95th percentile are the current margins of safety small.
13

Analysis of persistent organic pollutants in benthic fishes in the adjacent waters of Hsiao-Liu-Chiu,Taiwan

Wu, Meng-chung 26 December 2010 (has links)
Persistent organic pollutants (POPs) have attracted the attention of scientists because they have the following characteristics: long-distance transmission, persistence, bioaccumulation and chronic toxicity. Due to their high hydrophobicity, POPs are easily absorbed by the suspended particles in the marine environment. The suspended particles then settle into the soil may pass through the food chain, resulting in bioaccumulation and biomagnifications and causing potentially hazardous effects on the environment and human health. This study focuses on the analysis of the persistent organic pollutants in different parts of 10 kinds of benthic fishes, including the muscle and visceral mass, adjacent to Hsiao-Liu-Chiu. The samples were analyzed using accelerated solvent extraction (ASE), and alumina column purification. Fifteen polycyclic aromatic hydrocarbons (PAHs) were determined by using gas chromatograph / mass spectrometer (GC/MS). After florisil column purification, polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides (OCPs) were determined by using gas chromatograph / electron-capture detector (GC/ECD). The results showed that the concentration of PAHs range from 15 to 195 ng/g dw, with low ringed (3 rings) PAHs at a higher proportion. Total PCB concentrations range from 16 to 237 ng/g dw. The content of PCBs in muscles mainly consists of low chlorine numbers (1 to 4 chloride) -based, and in visceral and eggs the chlorine number (6 and 7 chlorine) are higher. The concentrations of OCPs range from 13 to 127 ng/g dw. Among the hexachlorocyclohexane (HCH) series, £^-HCH has the highest proportion, indicating the continued use of Lidane in recent years. In addition to the variance in POP levels among different species of fishes, different tissues also have high variations in PAH, PCB and OCP levels.
14

The Relationships between Perceptions of Organizational Politics and Employees¡¦ Job Attitude

Lee, An-Ming 04 July 2002 (has links)
The purpose of this investigation is to develop localized and suitable inventory for measuring perceptions of organizational politics¡]OP¡^in domestic enterprises and using the model proposed by Ferris et al.,¡]1989¡^study the relationships among the OP, job satisfaction, job stress & organizational commitment¡]employee¡¦s job attitudes¡^. The sample consisted of 227 employee selected from some traditional industry in Taiwan. The data were analyzed by applying statistical methods, including factor analysis, reliability, one-way ANOVA, correlation, regression and canonical correlation analysis. The major findings of this study are as fallow: The present study examined the dimensionality, reliability and validity of the Perceptions of Organizational Politics Scale¡]POPS¡^¡]Kacmar,1997¡^.Perceptions of organizational politics were found have a negative relationship with job satisfaction , job stress & organizational commitment. Understand, tenure , control and locus of control as a moderator of the relationships between perceptions of organizational politics & employee¡¦s job attitudes was examined. Results indicated that understand, tenure moderated the relationship between politics and job satisfaction; Locus of control moderated the relationship between politics and organizational commitment.
15

Sustainable phytoremediation potential of locally adapted plants in the Chinandega region, Nicaragua

Flores Carmenate, Student 1, förnamn:Ginnette January 2019 (has links)
In order to analyze the socio-economic and environmental system that is demanding soil remediation solutions in Chinandega region (Nicaragua), a DPSIR framework was used to model the system and to point out opportunities and limitations for phytoremediation applications in the region. An inventory of naturalized and autochthonous plant species was conducted while exploring their socioecological and economic co-benefits like potential candidates for sustainable phytoremediation strategies in Chinandega. Sustainable phytoremediation practices combined with agroforestry are unlikely to demand high cost inputs (if compared to conventional physicochemical soil treatments) but could potentially produce valuable socio-ecological and economic co-benefits which could enhance the cost-effectiveness of these practices in Chinandega (i.e. food production, fuelwood, building material, medicine, animal feed, carbon sequestration) among others (e.g. ecosystem services conservation, bioenergy production, essential oil production, phytomining, etc.). In the inventory of the existing vegetation in the two sites of study, 23 plant species resulted to be potential candidates for phytoremediation strategies in Chinandega according to the 9 criteria presented in this thesis. The capacity of POPs decontamination of these candidate plant species is still an unexplored field of research that would demand more detailed investigation in order to evaluate their further potential to phytoremediate these soils. However, the inventoried species clearly thrive in heavily contaminated sites which implies that they can withstand high levels of soil pollution, which makes them potential candidates for phytoremediation. The depth and scope of the contaminated soil layers, translocation patterns, phytoremediation capacity and the mechanisms involved calls for further investigations and feasibility studies based on this selected group of species. / För att analysera det socioekonomiska och miljömässiga system som kräver lösningar för rening av jord i Chinandega (Nicaragua) användes en DPSIR-modell för att kartlägga systemet och påvisa möjligheter och begränsningar för att tillämpa fytoremedieringsinitiativ i regionen. En inventering av naturligt anpassade växtarter genomfördes genom att undersöka deras socioekologiska och ekonomiska fördelar som potentiella kandidater för hållbara fytormedieringsstrategier i Chinandega. Hållbara fytoremedieringsmetoder kombinerat med skogsjordbruk kommer sannolikt inte att kräva högre kostnader (jämfört med konventionella fysikalisk-kemiska markbehandlingar) men kan potentiellt ge resultat när det gäller socioekonomiska och ekonomiska fördelar som skulle kunna förbättra kostnadseffektiviteten hos dessa metoder i Chinandega (d.v.s. livsmedelsproduktion, bränslevirke, byggmaterial, medicin, djurfoder, kolsekvestration) bland annat (t.ex. bevarande av ekosystemtjänster, bioenergiproduktion, essentiell oljeproduktion, fytominering, etc.). I inventeringen av den befintliga vegetationen i de två studieplatserna framkom 23 växtarter som potentiella kandidater för fytoremedieringsstrategier i Chinandega enligt de 9 kriterier som presenteras i denna avhandling. POP-dekontamineringskapaciteten hos dessa kandidatväxter är fortfarande ett outforskat område som skulle kräva mer forskning för att utvärdera potentialen att fytoremediera dessa jordar. Det faktum att dessa arter hittades på de starkt förorenade områdena innebär emellertid att de kan klara dessa nivåer av markförorening. Den identifierade kunskapsklyftan på translokeringsmönster av dessa arter, djup och omfattning av de förorenade markskikten och fytormedieringskapaciteten hos växterna och de involverade mekanismerna kräver ytterligare undersökningar och förstudier baserade på denna valda grupp av arter. / <p>2019-10-17</p>
16

Organoclorados em Toninhas, Pontoporia blainvillei (MAMMALIA: CETACEA) da região costeira do Estado de São Paulo, Brasil / Organochlorines in Franciscana dolphins, Pontoporia blainvillei (MAMMALIA: CETACEA) from the coast off São Paulo State, Brazil

Alonso, Mariana Batha 04 August 2008 (has links)
Os organoclorados constituem um dos principais grupos de poluentes que afetam os ecossistemas devido a sua grande persistência no ambiente e toxicidade para os organismos. A toninha, Pontoporia blainvillei, é um cetáceo costeiro, o único golfinho brasileiro considerado ameaçado de extinção por conta das atividades antrópicas. O objetivo desse trabalho foi avaliar a ocorrência de organoclorados em amostras de gordura subcutânea de indivíduos de Pontoporia blainvillei coletados na região costeira do Estado de São Paulo. A metodologia de extração e purificação das amostras foi testada e otimizada conforme procedimentos descritos na literatura. Foram realizadas as análises em 53 amostras de toninha (Pontoporia blainvillei): 29 machos e 24 fêmeas. Todas as concentrações de organoclorados apresentaram valores maiores nos machos, em comparação com as fêmeas de mesma maturidade. As concentrações dos compostos organoclorados nas toninhas do litoral paulista variaram, em ng.g-1 lipídios nos PCBs de 326 a 42.185, DDTs de 107 a 7.185, HCHs n.d. a 46, CHLs n.d. a 126, HCB < 2 a 133 e Mirex < 7 a 259. A razão DDTs/PCBs foi menor que 0,6 indicando uma maior contribuição industrial do que agrícola na área de estudo. Houve diferenças significativas dos valores dos OCs nas toninhas das localidades do litoral de São Paulo, com as maiores concentrações ocorrendo na Baixada Santista. / Organochlorines are one of the main pollutant groups that affect the ecosystems due to their environmental persistence and toxicity to the organisms. Franciscana dolphin, Pontoporia blainvillei, is a coastal cetacean, the only Brazilian dolphin considered threatened with extinction, due to the human activities. The aim of this work was evaluate the occurrence of organochlorines in the blubber samples of Pontoporia blainvillei collected on the coast of São Paulo State. The extraction and purification methodology was tested and optimized according to proceedings described in literature. A total of 53 individuals were analyzed: 29 males and 24 females. Organochlorine concentrations were higher in males when comparing to females with the same sexual maturity. PCBs were the predominant compounds (326 - 42185 ng g-1 lipid weight), followed by DDTs (107 - 7185 ng g-1 lipid wt), HCHs (n.d. - 46 ng g-1 lipid wt), CHLs (n.d. - 126 ng g-1 lipid wt), HCB (< 2 - 133 ng g-1 lipid wt) and Mirex (< 7 - 259 ng g-1 lipid wt). The ratio DDTs/PCBs was lesser than 0.6 indicating a major industrial than agricultural contribution in the study area. There were significant differences between the OCs values in franciscanas from 3 localities of São Paulo State coast: with the higher concentrations occurring in Baixada Santista.
17

Poluentes orgânicos e isótopos estáveis no ecossistema da Baía do Almirantado, Ilha Rei George, Antártida / Organic pollutants and stable isotopes in the ecosystem of Admiralty Bay, King George Island, Antarctica

Cipro, Caio Vinicius Zecchin 21 November 2011 (has links)
Apesar da pequena influência antrópica direta em seu território, a Antártida não pode ser considerada livre do alcance de poluentes. No presente estudo, avaliou-se a distribuição e transferência de poluentes orgânicos (PCBs, pesticidas organoclorados e PBDEs) em compartimentos abióticos (neve e água de degelo) e bióticos (liquens, musgos, invertebrados, peixes, ovos de aves e tecidos de aves e pinípedes, para os quais também foi aplicada análise isotópica de nitrogênio-15 e carbono-13) do ecossistema da Baía do Almirantado. Os compartimentos abióticos tiveram concentrações entre 1,4 e 156 pg L-1, apenas para grupos de organoclorados, com variação intra-sazonal importante e compatibilidade com níveis tróficos inferiores e amostras de vegetação, que por sua vez refletiram a importância de fontes secundárias de poluentes. Nos animais, grosso modo, os compostos prevalecentes (em ng g-1 peso úmido) foram PCBs, (6,82-1821), HCB (0,060-136) e DDTs, (0,410-524), níveis de duas a três ordens de grandeza superiores aos encontrados em vegetação. PBDEs ocorreram, de modo geral, em níveis uma ou duas ordens de grandeza abaixo dos organoclorados. A análise isotópica mostrou-se útil como ferramenta indicadora de nível trófico e origem de matéria orgânica consumida, correlacionando-se quantitativa e qualitativamente com os poluentes orgânicos pela indicação de fatores como stress nutricional e mudança de área de forrageio e/ou de dieta. Como alternativa, foi proposto um novo indicador de biomagnificação baseado no peso molecular dos PCBs, que apresentou resultados estatisticamente superiores ao ?15N na maioria dos casos. / Despite the small antropic direct influence on its territory, Antarctica cannot be considered out of pollutants\' reach. The present study evaluated the distribution and transfer of organic pollutants (PCBs, organochlorine pesticides and PBDEs) in both abiotic (snow and melting water) and biotic (lichens, mosses, invertebrates, fishes, bird eggs and bird and pinnipeds\' tissues, for which was also applied carbon-13 and nitrogen-15 stable isotopes analyses) compartments of the ecosystem from Admiralty Bay. Abiotic compartments showed concentrations between 1,4 and 156 pg L-1, only for organochlorine groups, with considerable intraseasonal variation and compatibility with lower trophic levels and vegetation samples, which in turn reflected the importance of secondary pollutants sources. In animal samples, grosso modo, the prevailing compounds were (in ng g-1 wet weight) PCBs (6,82-1821), HCB (0,060-136) and DDTs, (0,410-524), levels from two to three orders of magnitude superior to the ones found in vegetations. PBDEs occurred, in a general way, in levels from one to two orders of magnitude lower than the organochlorines. Stable isotope analyses proved useful as an indicator tool for trophic level and consumed organic matter, correlating itself in a qualitative and quantitative way with the organic pollutants by indication of factors as nutritional strees and variation in foraging areas and/or diet. As an alternative, a new biomagnifications indicator based on PCBs molecular weight was proposed, showing results statistically superior to the ?15N in the majority of the cases.
18

Determinação de POPs e agrotóxicos em leite materno empregando cromatografia a gás acoplada à espectrometria de massas com ionização química negativa (GC-NCI-MS) / Determination of POPs and pesticides in breast milk by gas chromatography-mass spectrometry with negative chemical ionization GC-NCI-MS)

Viera, Mariela de Souza 31 March 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Stockholm Convention was the first global attitude trying to preserve human health and the environment of the indiscriminate use of persistent organic pollutants (POPs), especially pesticides, which are characterized by being lipophilic and can bioaccumulate in fatty tissues including breast milk. However, POPs represent only a part of the chemicals with the potential for environmental pollution and human as new substances are constantly being developed and released into the environment. In this work, the sample preparation step was optimized based on the results of the factorial design 32 varying solvents and sorbents. The method was validated for 54 compound using a mixture of hexane:acetone for extraction, clean-up by dispersible solid phase extraction (d-SPE) using activated Florisil® and determination by gas chromatography coupled to mass spectrometry using negative chemical ionization (GC-NCI-MS). The matrix effect was compensated by the use of extracted analytical curve. The validation of the method showed satisfactory results for linearity, accuracy (recovery between 71.9 and 119.8%) and precision (RSD <29%). An evaporation step of the extract concentrated the analytes enabling low detection (3 to 26 ng g-1 of fat) and quantitation (9 to 86 ng g-1 of fat) limits. The method was applied to 20 samples of breast milk collected in different regions of Rio Grande do Sul state, Brazil, all of which contained at least one of the studied compounds. With principal component analysis of the results, it was possible to relate the pesticides detected in relation to the city of origin of the samples and the number of nursing mother's pregnancies. Considering that breast milk is a complex matrix, the analytical method was effective for the determination of trace levels of POPs and pesticides in breast milk and can be applied in monitoring analysis of human exposure to these contaminants. / A Convenção de Estocolmo foi a primeira atitude mundial a tentar preservar a saúde humana e o ambiente do uso indiscriminado de agrotóxicos, especialmente os poluentes orgânicos persistentes (POPs), que se caracterizam por serem lipofílicos podendo bioacumular nos tecidos adiposos e também no leite materno. Porém, os POPs constituem apenas uma parte dos produtos químicos com potencial de contaminação ambiental e humana uma vez que novas substâncias estão constantemente sendo desenvolvidas e liberadas no ambiente. Neste trabalho a etapa de preparo de amostra foi otimizada com base nos resultados do planejamento fatorial 32 variando solventes e sorventes. O método foi validado para 54 compostos utilizando uma mistura de hexano:acetona para a extração, limpeza do extrato por extração em fase sólida dispersiva (d-SPE) empregando Florisil® ativado e determinação por cromatografia a gás acoplada à espectrometria de massas com ionização química negativa (GC-NCI-MS). O efeito matriz foi compensado pela utilização de curva analítica extraída. A validação do método apresentou resultados satisfatórios para linearidade, exatidão (recuperação entre 719-119,8%) e precisão (RSD <29%). Uma etapa de evaporação do extrato concentrou os analitos possibilitando analisar baixos limites de detecção (3 a 26 ng g-1 de gordura) e de quantificação (9 a 86 ng g-1 de gordura). O método foi aplicado em 20 amostras de leite materno coletadas em diferentes regiões do estado do Rio Grande do Sul, Brasil, das quais todas apresentaram pelo menos um dos compostos estudados. Com análise por componentes principais dos resultados foi possível relacionar os agrotóxicos detectados com relação a cidade de origem das amostras e número de gestações da nutriz. Considerando que o leite materno é uma matriz complexa, o método analítico foi eficaz para a determinação em nível de traço de POPs e agrotóxicos em leite materno, podendo ser aplicado em análise de monitoramento da exposição humana a esses contaminantes.
19

Determinação de poluentes orgânicos persistentes (pops) em leite materno: desenvolvimento e aplicação de método analítico empregando GC-NCI-MS / Determination of persistent organic pollutants (POPs) in breast milk: development and application of an analytical method using GC-NCI-MS

Ferronato, Giovana 12 March 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Persistent Organic Pollutants (POPs) receive this designation because of the time that remain unchanged in the environment. From the 1960s there was already evidence of the presence of these compounds in sediment, breast milk, fish and eggs. The food chain can be considered a source of contamination of humans by these compounds due to bioaccumulation. The fat contained in milk can accumulate POPs, so this matrix has been used as environmental bioindicator. The currently available methods for the determination of these compounds in breast milk involve, in general, multi-step sample preparation and quantification techniques with low selectivity, have high cost and are time consuming. Thus, this study aimed to develop a fast and efficient method based on sample preparation using the QuEChERS method combined Gas Chromatography coupled to Mass Spectrometry with negative chemical ionization (GC-NCI-MS). In this work we optimized the sample preparation step for the determination of 15 POPs in breast milk (Alpha HCH, beta HCH, gamma HCH, hexachlorobenzene, heptachlor, andrin, dieldrin, endrin, 2,4 DDE, DDT, endosulfan alpha, beta endosulfan, endosulfan sulfate and mirex) using 6 mL of sample extracted with 6 mL of acetonitrile. In the partition step was used 2.6 g MgSO4 and 0.6 g of NaCl. The extract clean-up was performed by dispersive solid-phase extraction of 4 mL of extract and 600 mg of MgSO4 and 200 mg of C18. The extract was evaporated in a Turbovap system and redissolved in 200 μL acetonitrile for the determination by GC-NCI-MS. The method was validated showing linearity for the 15 evaluated compounds. Recoveries of the analytes ranged between 62 and 120% with precision within the acceptable range (RSD <19%). The limits of detection for breast milk, in terms of fat percentage, ranged from 0.75 to 7.5 ng g-1 and the method limits of quantification ranged from 2.5 to 25 ng g-1. The method was applied to 20 samples of breast milk from different regions of the Rio Grande do Sul state, of which only 25% were not contaminated by the studied POPs and the others showed values below the LQ. It is important to emphasize that this is an unpublished work in the area of POPs determination in breast milk by GC-NCI-MS, and could be a basis for future works in this area. / Os Poluentes Orgânicos Persistentes (POPs) recebem essa denominação devido ao tempo que permanecem inalterados no meio ambiente. A partir dos anos 1960 já havia indícios da presença desses compostos em sedimentos, leite materno, peixe e ovos. A cadeia alimentar pode ser considerada uma fonte de contaminação do ser humano por esses compostos devido à bioacumulação. A gordura contida no leite materno pode acumular os POPs, por isso esta matriz vem sendo utilizada como bioindicador ambiental. Os métodos disponíveis atualmente para a determinação desses compostos em leite materno envolvem, em geral, várias etapas de preparo de amostra e quantificação por técnicas pouco seletivas, apresentam alto custo e demanda de tempo. Assim, esse trabalho visou o desenvolvimento de um método rápido e eficiente baseado no preparo de amostra empregando o método QuEChERS combinado a Cromatografia à Gás, acoplada à Espectrometria de Massas com ionização química negativa (GC-NCI-MS). Neste trabalho otimizou-se a etapa de preparo de amostra para a determinação de 15 POPs em leite materno (HCH alfa, HCH beta, HCH gama, hexaclorobenzeno, heptacloro, andrin, dieldrin, endrin, 2,4 DDE, DDT, endosulfan alfa, endosulfan beta, endosulfan sulfato e mirex) utilizando 6 mL de amostra e extração com 6 mL de acetonitrila. Na etapa de partição utilizou-se 2,6 g de MgSO4 e 0,6 g de NaCl. A limpeza do extrato foi realizada por extração em fase sólida dispersiva de 4 mL de extrato e 600 mg de MgSO4 e 200 mg de C18. O extrato foi evaporado em sistema Turbovap e redissolvido em 200 μL de acetonitrila para determinação por GC-(NCI)-MS. O método foi validado apresentando linearidade para os 15 compostos em estudo. As recuperações dos analitos variaram entre 62 e 120%, com valores de precisão dentro da faixa aceitável (RSD < 19%). Os limites de detecção do método para leite materno em termos de percentual de gordura variaram de 0,75 a 7,5 ng g-1e os limites de quantificação do método variaram de 2,5 a 25 ng g-1. O método foi aplicado para 20 amostras de leite materno de diferentes regiões do estado do Rio Grande do Sul, das quais, apenas 25% não apresentaram contaminação pelos POPs estudados e as demais apresentaram valores menores que o LQ. É importante destacar que trata-se de um trabalho inédito na área de determinação de POPs em leite materno empregando GC-NCI-MS, podendo servir de base para trabalhos futuros nessa área.
20

Poluentes orgânicos e isótopos estáveis no ecossistema da Baía do Almirantado, Ilha Rei George, Antártida / Organic pollutants and stable isotopes in the ecosystem of Admiralty Bay, King George Island, Antarctica

Caio Vinicius Zecchin Cipro 21 November 2011 (has links)
Apesar da pequena influência antrópica direta em seu território, a Antártida não pode ser considerada livre do alcance de poluentes. No presente estudo, avaliou-se a distribuição e transferência de poluentes orgânicos (PCBs, pesticidas organoclorados e PBDEs) em compartimentos abióticos (neve e água de degelo) e bióticos (liquens, musgos, invertebrados, peixes, ovos de aves e tecidos de aves e pinípedes, para os quais também foi aplicada análise isotópica de nitrogênio-15 e carbono-13) do ecossistema da Baía do Almirantado. Os compartimentos abióticos tiveram concentrações entre 1,4 e 156 pg L-1, apenas para grupos de organoclorados, com variação intra-sazonal importante e compatibilidade com níveis tróficos inferiores e amostras de vegetação, que por sua vez refletiram a importância de fontes secundárias de poluentes. Nos animais, grosso modo, os compostos prevalecentes (em ng g-1 peso úmido) foram PCBs, (6,82-1821), HCB (0,060-136) e DDTs, (0,410-524), níveis de duas a três ordens de grandeza superiores aos encontrados em vegetação. PBDEs ocorreram, de modo geral, em níveis uma ou duas ordens de grandeza abaixo dos organoclorados. A análise isotópica mostrou-se útil como ferramenta indicadora de nível trófico e origem de matéria orgânica consumida, correlacionando-se quantitativa e qualitativamente com os poluentes orgânicos pela indicação de fatores como stress nutricional e mudança de área de forrageio e/ou de dieta. Como alternativa, foi proposto um novo indicador de biomagnificação baseado no peso molecular dos PCBs, que apresentou resultados estatisticamente superiores ao ?15N na maioria dos casos. / Despite the small antropic direct influence on its territory, Antarctica cannot be considered out of pollutants\' reach. The present study evaluated the distribution and transfer of organic pollutants (PCBs, organochlorine pesticides and PBDEs) in both abiotic (snow and melting water) and biotic (lichens, mosses, invertebrates, fishes, bird eggs and bird and pinnipeds\' tissues, for which was also applied carbon-13 and nitrogen-15 stable isotopes analyses) compartments of the ecosystem from Admiralty Bay. Abiotic compartments showed concentrations between 1,4 and 156 pg L-1, only for organochlorine groups, with considerable intraseasonal variation and compatibility with lower trophic levels and vegetation samples, which in turn reflected the importance of secondary pollutants sources. In animal samples, grosso modo, the prevailing compounds were (in ng g-1 wet weight) PCBs (6,82-1821), HCB (0,060-136) and DDTs, (0,410-524), levels from two to three orders of magnitude superior to the ones found in vegetations. PBDEs occurred, in a general way, in levels from one to two orders of magnitude lower than the organochlorines. Stable isotope analyses proved useful as an indicator tool for trophic level and consumed organic matter, correlating itself in a qualitative and quantitative way with the organic pollutants by indication of factors as nutritional strees and variation in foraging areas and/or diet. As an alternative, a new biomagnifications indicator based on PCBs molecular weight was proposed, showing results statistically superior to the ?15N in the majority of the cases.

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