The importance of the cryosphere, and of sea ice in particular, for contaminant transport and redistribution in the Arctic was pointed out in the literature. However, studies on contaminants in sea ice are scarce, and entirely neglect the sea ice geophysical and thermodynamic characteristics as well as interactions between various cryospheric compartments. This thesis addresses those gaps. Ice formation was shown to have a significant concentrating impact on the levels of HCHs in the water just beneath the ice. Both geophysical and thermodynamic conditions in sea ice were shown to be crucial in understanding pathways of accumulation or rejection of HCHs. Although HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring, upward migration of brine from the ice to the snow in the winter has an effect on levels of HCHs in the snow by up to 50 %. In the spring, when snow melt water percolates into the ice delivering HCHs to the upper ocean via desalination by flushing, levels of HCHs in the ice can increase by up to 2 %-18 % and 4 %-32 % for α- and γ-HCH, respectively. Brine contained within sea ice currently exhibits the highest HCH concentrations in any abiotic Arctic environment, exceeding under-ice water concentrations by a factor of 3 in the spring. This circumstance suggests that the brine ecosystem has been, and continues to be, the most exposed to HCHs. α-HCH levels were shown to decrease rapidly in the last two decades in the Polar Mixed Layer (PML) and the Pacific Mode Layer (PL) of the Beaufort Sea due to degradation. If the rate of degradation does not change in the near future, the majority of α-HCH could be eliminated from the Beaufort Sea by 2020, with concentrations in 2040 dropping to < 0.006 ng/L and < 0.004 ng/L in the PML and the PL, respectively. Elimination of α-HCH from sea water takes significantly longer than from the atmosphere, with a lag of approximately two decades.

The importance of the cryosphere, and of sea ice in particular, for contaminant transport and redistribution in the Arctic was pointed out in the literature. However, studies on contaminants in sea ice are scarce, and entirely neglect the sea ice geophysical and thermodynamic characteristics as well as interactions between various cryospheric compartments. This thesis addresses those gaps. Ice formation was shown to have a significant concentrating impact on the levels of HCHs in the water just beneath the ice. Both geophysical and thermodynamic conditions in sea ice were shown to be crucial in understanding pathways of accumulation or rejection of HCHs. Although HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring, upward migration of brine from the ice to the snow in the winter has an effect on levels of HCHs in the snow by up to 50 %. In the spring, when snow melt water percolates into the ice delivering HCHs to the upper ocean via desalination by flushing, levels of HCHs in the ice can increase by up to 2 %-18 % and 4 %-32 % for α- and γ-HCH, respectively. Brine contained within sea ice currently exhibits the highest HCH concentrations in any abiotic Arctic environment, exceeding under-ice water concentrations by a factor of 3 in the spring. This circumstance suggests that the brine ecosystem has been, and continues to be, the most exposed to HCHs. α-HCH levels were shown to decrease rapidly in the last two decades in the Polar Mixed Layer (PML) and the Pacific Mode Layer (PL) of the Beaufort Sea due to degradation. If the rate of degradation does not change in the near future, the majority of α-HCH could be eliminated from the Beaufort Sea by 2020, with concentrations in 2040 dropping to < 0.006 ng/L and < 0.004 ng/L in the PML and the PL, respectively. Elimination of α-HCH from sea water takes significantly longer than from the atmosphere, with a lag of approximately two decades.

Huntington's disease (HD) is one of the incurable and fatal diseases. HD belongs to the monogenic neurodegenerative diseases. According to the number of the CAG repetitions in the gene coding huntingtin, the onset of the disease is in childhood (5%), in the middle age, which is the most common (90%) and in the older age (5%). Beginning of the disease is manifested by changes in behavior; including problems with coordination and movement. Later, there is a psychological change. The disease leads to death. Until now, there is no effective curative treatment. In 2009, we created a model of the transgenic minipigs (TgHD) carrying the N - terminal part of the human mutant huntingtin (mtHtt) at our Institute in Liběchov. The number of offsprings and the resemblance in physiology and morphology between the pig (Sus scrofa) and humans (Homo sapiens) give us opportunities not only to study changes not only in central nerve organs, but also in peripheral tissues. The reproductive problems of TgHD boars were observed as the first phenotypic changes. Therefore, my work focuses at first on a study of the reproduction parameters of TgHD boars as well as ultrastructural, immunocytochemical and biochemical changes in testes and spermatozoa. In PhD thesis, I described in details the reproductive defects in TgHD...

O Hexaclorociclohexano (HCH) é um inseticida do grupo dos organoclorados, composto por uma mistura de isômeros formados durante a síntese química, através de sucessivas adições de cloro ao benzeno. Estes isômeros podem contaminar não só o meio ambiente como também a população que tenha contato direto ou indireto com os resíduos. Nas décadas de 70 e 80, foi utilizado um produto comercial composto pelo ativo HCH comercializado como \"Hexabel®\" no controle de insetos xilófagos no Acervo Histórico de Joinville em Santa Catarina. A aplicação do inseticida foi realizada pelos próprios funcionários do Arquivo Histórico, e houve intensa manipulação dos documentos tratados durante uma mudança do prédio o presente trabalho teve como objetivo validar uma metodologia de determinação de resíduos do HCH e seus isômeros em soro sangüíneo, e analisar o grau de exposição dos funcionários e ex-funcionários do Arquivo Histórico de Joinville ao produto. Foram realizados exames sorológicos em todos os funcionários e ex - funcionários do local e também na população que sabidamente nunca tiveram contato com o ativo, denominada população controle. As análises foram realizadas após a validação do método multiresíduos que obtém todos os ativos em uma única extração e tem detecção por Cromatografia a gás com detector de captura (GC-ECD) de elétrons. Os resultados comprovaram comprovaram a eficiência do método, através de dados em conformidade com os critérios do ensaio. Os resultados obtidos no estudo da população mostraram que a quantidade de HCH no soro sangüíneo de funcionários, ex-funcionários e da população controle estão abaixo do limite de quantificação de 0,04&mu;g dL-1 para Alfa HCH e Gama HCH \"Lindana\" e 0,08&mu;g dL-1 para Beta e Delta HCH. / Hexachlorcyciohexane (HCH) is an organochloride insecticide formed by a mixture of chemical isomers produced during its chemical synthesis, obtained after successive inserts of chlorine atoms on benzene molecule. These isomers may contaminate both the environment and the people who had direct or indirect contact with the HCH residues. On 70\'s and 80\'s, its was used a commercial product which contained HCH on its formula and was commercialized as Hexabel®. The product was used to control the xylophage insect population on the Historical Archieve of Joinville, at Santa Catarina, Brazil. The own employees did the insecticide application and there was an intensive manipulation of the treated material during a building change. The objective of this work was to validate a methodology to quantify the HCH residues and its isomers on blood plasma and analyze the employee\'s exposure extent to the chemical. It was done serological investigation on employees, former-employees and on non-exposed people, which was classified as the control population. The analyses were done after the methodology validation. The method was capable to obtain all isomers on a unique extraction and the detection and quantification were done by gas chromatography with electron-capture detector (GC-ECD). The results obtained showed that the proposed method is accurate, and that the amount of HCH residues on blood plasma of all individuals analyzed was lower than the quantification limits established to the method, which were 0,04 &mu;g dL-1 for the alpha- and gamma- HCH (lindana) and 0,08 &mu;g dL-1 for the beta- and delta- HCH.

Humans are continuously exposed to complex mixtures of anthropogenic chemicals. This thesis focus on human exposure to persistent organic pollutants (POPs). POPs ability to bioaccumulate and biomagnify together with the extensive historical use of POPs in e.g. agriculture and industry have resulted in detection of these compounds in humans and animals from all over the world. Adverse health effects caused by POPs are of particular concern for newborns and young individuals. The objective of this thesis is to assess human exposure to a selected set of POPs and their metabolites. More specifically, one aim of my thesis is to determine the exposure to polychlorinated biphenyls (PCBs) and in particular their methylsulfonyl and hydroxylated metabolites in humans from a “hot-spot” area of PCB contamination in eastern Slovakia. The maternal transfer of these chemicals is studied. Further, another specific aim is to determine occurrence, levels and, when possible, temporal trends of POPs in children and adults from three developing countries, Nicaragua, Guinea-Bissau and Bangladesh. High concentrations of PCBs and their metabolites are shown in men and women from Michalovce in eastern Slovakia. Placental transfer of methylsulfonyl-metabolites of PCBs and 4,4’-DDE was observed for the first time. Decreasing temporal trends of the majority of POPs are shown in serum from a cohort of policemen from Guinea-Bissau. In contrast, the levels of polybrominated diphenyl ethers (PBDEs) show an increasing time trend. Within five years, decreasing levels of POPs were also shown in children working and living at a waste disposal site in Nicaragua. Children working and living at waste disposal sites in Bangladesh have considerably lower levels of POPs compared to the children from Nicaragua except for 4,4’-DDT and 4,4’-DDE that are present at very high concentrations, indicating ongoing use of technical DDT. There are many studies on levels and trends of environmental pollutants from the developed industrial countries in the world, whereas data from developing countries is still scarce. This thesis contributes to partly fill this data gap since it includes assessments of POPs in children and adults from four countries on four continents. / At the time of doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Manuscript. Paper 6: Manuscript.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Made available in DSpace on 2014-06-11T19:29:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-14Bitstream added on 2014-06-13T19:17:18Z : No. of bitstreams: 1 araujo_mm_me_sjrp.pdf: 1487042 bytes, checksum: 0cb591f27f66e82e9cdb8ae34683ea7d (MD5) / Instituto de Pesquisas Tecnologicas / Este trabalho apresenta o estudo experimental do comportamento térmico do inseticida hexaclorociclohexano, para avaliar se a técnica de dessorção térmica é indicada no processo de descontaminação do solo para este tipo de contaminante. Para a realização deste estudo, amostras do inseticida foram submetidas a diversas temperaturas com diferentes tempos, no intuito de avaliar as perdas de massa e verificar a possível geração de contaminantes por meio das emissões gasosas durante o aquecimento. Os resultados indicaram que no aquecimento do inseticida houve liberação de cloro e possível decomposição do inseticida e das impurezas presentes na amostra. Observou-se também a formação de bifenilas policloradas, furanos, benzeno, clorobenzeno, dentre outros, e a volatilização dos compostos presentes na amostra. A concentração dos isômeros do inseticida quando submetido à temperatura de 350°C diminuiu após quatro dias de aquecimento, ao ponto de ficar próximos dos valores orientadores para solo estabelecidos pela CETESB. Pode-se concluir que o comportamento térmico do inseticida HCH mostrou-se satisfatório para a aplicação da técnica de dessorção térmica, pois sua concentração diminuiu significativamente nos experimentos realizados. Verifica-se que a aplicação da técnica exige o tratamento das emissões gasosas geradas / This paper presents the experimental study of the thermal behavior of the insecticide hexachlorocyclohexane, to evaluate the technique of thermal desorption is indicated in the process of decontamination of soil for this type of contaminant. For this study, samples of the insecticide were subjected to different temperatures at different times, in order to evaluate the mass losses and check the possible generation of contaminants through gaseous emissions during heating. The result indicates that the heating of the insecticide was release of chlorine and possible decomposition of the insecticide and the impurities in the sample. We also observed the formation of polychlorinated biphenyls, furans, benzene, chlorobenzene, among others, and evaporation of the compounds present in the sample. The concentration of the insecticide isomers when subjected to a temperature of 350 °C decreased after four days of heating, the point of being close to the guiding values for soil established by CETESB. It can be concluded that the thermal behavior of the insecticide HCH was satisfactory for the application of the technique of thermal desorption, since its concentration decreased significantly in the experiments. It appears that the technique requires the treatment of gaseous emissions generated

O Hexaclorociclohexano (HCH) é um inseticida do grupo dos organoclorados, composto por uma mistura de isômeros formados durante a síntese química, através de sucessivas adições de cloro ao benzeno. Estes isômeros podem contaminar não só o meio ambiente como também a população que tenha contato direto ou indireto com os resíduos. Nas décadas de 70 e 80, foi utilizado um produto comercial composto pelo ativo HCH comercializado como \"Hexabel®\" no controle de insetos xilófagos no Acervo Histórico de Joinville em Santa Catarina. A aplicação do inseticida foi realizada pelos próprios funcionários do Arquivo Histórico, e houve intensa manipulação dos documentos tratados durante uma mudança do prédio o presente trabalho teve como objetivo validar uma metodologia de determinação de resíduos do HCH e seus isômeros em soro sangüíneo, e analisar o grau de exposição dos funcionários e ex-funcionários do Arquivo Histórico de Joinville ao produto. Foram realizados exames sorológicos em todos os funcionários e ex - funcionários do local e também na população que sabidamente nunca tiveram contato com o ativo, denominada população controle. As análises foram realizadas após a validação do método multiresíduos que obtém todos os ativos em uma única extração e tem detecção por Cromatografia a gás com detector de captura (GC-ECD) de elétrons. Os resultados comprovaram comprovaram a eficiência do método, através de dados em conformidade com os critérios do ensaio. Os resultados obtidos no estudo da população mostraram que a quantidade de HCH no soro sangüíneo de funcionários, ex-funcionários e da população controle estão abaixo do limite de quantificação de 0,04&mu;g dL-1 para Alfa HCH e Gama HCH \"Lindana\" e 0,08&mu;g dL-1 para Beta e Delta HCH. / Hexachlorcyciohexane (HCH) is an organochloride insecticide formed by a mixture of chemical isomers produced during its chemical synthesis, obtained after successive inserts of chlorine atoms on benzene molecule. These isomers may contaminate both the environment and the people who had direct or indirect contact with the HCH residues. On 70\'s and 80\'s, its was used a commercial product which contained HCH on its formula and was commercialized as Hexabel®. The product was used to control the xylophage insect population on the Historical Archieve of Joinville, at Santa Catarina, Brazil. The own employees did the insecticide application and there was an intensive manipulation of the treated material during a building change. The objective of this work was to validate a methodology to quantify the HCH residues and its isomers on blood plasma and analyze the employee\'s exposure extent to the chemical. It was done serological investigation on employees, former-employees and on non-exposed people, which was classified as the control population. The analyses were done after the methodology validation. The method was capable to obtain all isomers on a unique extraction and the detection and quantification were done by gas chromatography with electron-capture detector (GC-ECD). The results obtained showed that the proposed method is accurate, and that the amount of HCH residues on blood plasma of all individuals analyzed was lower than the quantification limits established to the method, which were 0,04 &mu;g dL-1 for the alpha- and gamma- HCH (lindana) and 0,08 &mu;g dL-1 for the beta- and delta- HCH.

In the studies underlying this thesis, various source tracing techniques were applied to environmental samples from the Baltic region. Comprehensive sampling and analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in surface sediments in Swedish coastal and offshore areas resulted in a unique data set for this region. Nearly 150 samples of surface sediments were analyzed for all tetra- to octa-chlorinated PCDD/Fs. The levels showed large spatial variability with hotspots in several coastal regions. Neither Sweden nor the EU has introduced guideline values for PCDD/Fs in sediment, but comparisons to available guidelines and quality standards from other countries indicate that large areas of primarily coastal sediments may constitute a risk to marine organisms. Multivariate pattern analysis techniques and receptor models, such as Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF), were used to trace sources. These analyses suggested that three to six source types can explain most of the observed pattern variations found in the sediment samples. Atmospheric deposition was suggested as the most important source to offshore areas, thus confirming earlier estimates. However, spatial differences indicated a larger fraction of local/regional atmospheric sources, characterized by PCDFs, in the south. This was indicated by the identification of several patterns of atmospheric origin. In coastal areas, the influence of direct emission sources was larger, and among these, chlorophenol used for wood preservation and emissions from pulp/paper production and other wood related industry appeared to be most important. The historic emissions connected to processes involving chemical reactions with chlorine (e.g. pulp bleaching) were found to be of less importance except at some coastal sites. The analysis of PCDD/Fs in Baltic herring also revealed spatial variations in the levels and pollution patterns along the coast. The geographical match against areas with elevated sediment levels indicated that transfer from sediments via water to organisms was one possible explanation. Fugacity, a concept used to predict the net transport direction between environmental matrices, was used to explore the gas exchange of hexachlorocyclohexanes (HCHs) and polychlorinated biphenyls (PCBs) between air and water. These estimates suggested that, in the Kattegat Sea, the gaseous exchange of HCHs primarily resulted in net deposition while PCBs were net volatilized under certain environmental conditions. The study also indicated that, while the air concentrations of both PCBs and γ-HCH are mostly dependent upon the origin of the air mass, the fluctuations in α-HCH were primarily influenced by seasonal changes.

The electronic properties of Triphenylamine (TPA) in gas phase and adsorbed on gold(111) have been simulated with Quantum Espresso using Density Functional Theory (DFT). To better understand how the presence of a gold surface affects sunlight absorption in the system, partial Density Of States (pDOS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) of the system have been calculated. To describe the electronic excitation, three different methods have been used, No Core Hole (NCH), Full Core Hole (FCH) and Half Core Hole (HCH) approximation. The excitation of the TPA molecule was made in the nitrogen (N) atom and in the four different carbon (C) atoms with different electronic environments, C-ipso, C-ortho, C-meta and C-para. When using the HCH method, the absorbing atom must be described by a pseudopotential (PP) which includes half of a hole in the 1s orbital. This PP has been generated and a detailed summary of the process is described. The TPA/gold system relaxes to a position with the central N atom of TPA above an gold (Au) atom in the second layer of the surface and at a distance of 3.66 Angstrom, to the first layer. TPA keeps its symmetry with only small differences in the length of atomic bonds when adsorbed. The most striking result of this study is how the band gap of TPA is affected by the gold layer. From the pDOS we can observe that TPA in gas phase has a clear band gap of 2.2 eV with C-ortho dominating in the valence region and the four carbons dominating in the first unoccupied states. When depositing the molecule on the surface of Au(111), the band gap is essentially gone and a number of states appear between the previous highest occupied and lowest unoccupied molecular orbital in TPA. These new states align in energy with three clusters of states of the gold suggesting an interaction between the molecule and the surface. In the generated NEXAFS of nitrogen and carbon in TPA gas phase, one can observe a small pre-peak before the first unoccupied state. This is reinforced when adsorbing the molecule, which generates a pre-peak of approximately 3 eV in width. The pre-peak is connected to the new peaks seen in pDOS, correlating with experimental results on the same system.