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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

Cytochrome P4501A Induction by Highly Purified Hexachlorobenzene in Primary Cultures of Avian Hepatocytes

Mundy, Lukas 05 October 2011 (has links)
Hexachlorobenzene (HCB) is a persistent organic pollutant that was primarily produced for use as a fungicide dating back to the 1940s. Worldwide emissions have declined steadily over the past forty years, but HCB is still produced as a by-product of a number of industrial processes and is still detected in remote locations around the globe. Many studies have been conducted to determine the toxic and biochemical effects of HCB, but it has been suggested that reported toxic and biochemical effects initially attributed to HCB exposure may have actually been elicited by contamination of HCB by polychlororinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs). This thesis investigates whether highly purified HCB (HCB-P; defined as HCB containing < 0.2 ppb of any PCDD, PCDF, or co-planar PCB congener [the detection limit of current analytical methods]) can induce cytochrome P4501A (CYP1A) in three avian species in vitro. Primary cultures of chicken (Gallus gallus domesticus), ring-necked pheasant (Phasianus colchicus) and Japanese quail (Corturnix japonica) embryo hepatocytes were used to compare the potencies of reagent-grade (RG-HCB), HCB-P and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as inducers of ethoxyresorufin O-deethylase (EROD) activity, CYP1A4 messenger ribonucleic acid (mRNA) and CYP1A5 mRNA. The potencies of two mono-ortho substituted PCBs, 2,3,3’,4,4’-pentachlorobiphenyl (PCB 105) and 2,3’,4,4’,5-pentachlorobiphenyl (PCB 118) were also assessed in chicken embryo hepatocytes using the same endpoints. All compounds induced EROD activity and up-regulated CYP1A4/5 mRNAs in the hepatocytes of each species. The potency of HCB relative to the potency of TCDD (ReP) was 0.0001, 0.001 and 0.01 in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes, respectively. ECthreshold values were suggested to be more appropriate than EC50 values because ECthreshold values account for differences in maximal EROD and CYP1A4/5 mRNA levels that are observed with HCB exposure in avian embryo hepatocytes more so than EC50 values. Differences in species sensitivity to HCB were also assessed, and did not vary as greatly as the listed ReP values. The results presented herein suggest that HCB is capable of inducing effects downstream of activation of the aryl hydrocarbon receptor, and may warrant its inclusion in the World Health Organization’s toxic equivalency concept.
2

Cytochrome P4501A Induction by Highly Purified Hexachlorobenzene in Primary Cultures of Avian Hepatocytes

Mundy, Lukas 05 October 2011 (has links)
Hexachlorobenzene (HCB) is a persistent organic pollutant that was primarily produced for use as a fungicide dating back to the 1940s. Worldwide emissions have declined steadily over the past forty years, but HCB is still produced as a by-product of a number of industrial processes and is still detected in remote locations around the globe. Many studies have been conducted to determine the toxic and biochemical effects of HCB, but it has been suggested that reported toxic and biochemical effects initially attributed to HCB exposure may have actually been elicited by contamination of HCB by polychlororinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs). This thesis investigates whether highly purified HCB (HCB-P; defined as HCB containing < 0.2 ppb of any PCDD, PCDF, or co-planar PCB congener [the detection limit of current analytical methods]) can induce cytochrome P4501A (CYP1A) in three avian species in vitro. Primary cultures of chicken (Gallus gallus domesticus), ring-necked pheasant (Phasianus colchicus) and Japanese quail (Corturnix japonica) embryo hepatocytes were used to compare the potencies of reagent-grade (RG-HCB), HCB-P and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as inducers of ethoxyresorufin O-deethylase (EROD) activity, CYP1A4 messenger ribonucleic acid (mRNA) and CYP1A5 mRNA. The potencies of two mono-ortho substituted PCBs, 2,3,3’,4,4’-pentachlorobiphenyl (PCB 105) and 2,3’,4,4’,5-pentachlorobiphenyl (PCB 118) were also assessed in chicken embryo hepatocytes using the same endpoints. All compounds induced EROD activity and up-regulated CYP1A4/5 mRNAs in the hepatocytes of each species. The potency of HCB relative to the potency of TCDD (ReP) was 0.0001, 0.001 and 0.01 in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes, respectively. ECthreshold values were suggested to be more appropriate than EC50 values because ECthreshold values account for differences in maximal EROD and CYP1A4/5 mRNA levels that are observed with HCB exposure in avian embryo hepatocytes more so than EC50 values. Differences in species sensitivity to HCB were also assessed, and did not vary as greatly as the listed ReP values. The results presented herein suggest that HCB is capable of inducing effects downstream of activation of the aryl hydrocarbon receptor, and may warrant its inclusion in the World Health Organization’s toxic equivalency concept.
3

Cytochrome P4501A Induction by Highly Purified Hexachlorobenzene in Primary Cultures of Avian Hepatocytes

Mundy, Lukas 05 October 2011 (has links)
Hexachlorobenzene (HCB) is a persistent organic pollutant that was primarily produced for use as a fungicide dating back to the 1940s. Worldwide emissions have declined steadily over the past forty years, but HCB is still produced as a by-product of a number of industrial processes and is still detected in remote locations around the globe. Many studies have been conducted to determine the toxic and biochemical effects of HCB, but it has been suggested that reported toxic and biochemical effects initially attributed to HCB exposure may have actually been elicited by contamination of HCB by polychlororinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs). This thesis investigates whether highly purified HCB (HCB-P; defined as HCB containing < 0.2 ppb of any PCDD, PCDF, or co-planar PCB congener [the detection limit of current analytical methods]) can induce cytochrome P4501A (CYP1A) in three avian species in vitro. Primary cultures of chicken (Gallus gallus domesticus), ring-necked pheasant (Phasianus colchicus) and Japanese quail (Corturnix japonica) embryo hepatocytes were used to compare the potencies of reagent-grade (RG-HCB), HCB-P and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as inducers of ethoxyresorufin O-deethylase (EROD) activity, CYP1A4 messenger ribonucleic acid (mRNA) and CYP1A5 mRNA. The potencies of two mono-ortho substituted PCBs, 2,3,3’,4,4’-pentachlorobiphenyl (PCB 105) and 2,3’,4,4’,5-pentachlorobiphenyl (PCB 118) were also assessed in chicken embryo hepatocytes using the same endpoints. All compounds induced EROD activity and up-regulated CYP1A4/5 mRNAs in the hepatocytes of each species. The potency of HCB relative to the potency of TCDD (ReP) was 0.0001, 0.001 and 0.01 in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes, respectively. ECthreshold values were suggested to be more appropriate than EC50 values because ECthreshold values account for differences in maximal EROD and CYP1A4/5 mRNA levels that are observed with HCB exposure in avian embryo hepatocytes more so than EC50 values. Differences in species sensitivity to HCB were also assessed, and did not vary as greatly as the listed ReP values. The results presented herein suggest that HCB is capable of inducing effects downstream of activation of the aryl hydrocarbon receptor, and may warrant its inclusion in the World Health Organization’s toxic equivalency concept.
4

Cytochrome P4501A Induction by Highly Purified Hexachlorobenzene in Primary Cultures of Avian Hepatocytes

Mundy, Lukas January 2011 (has links)
Hexachlorobenzene (HCB) is a persistent organic pollutant that was primarily produced for use as a fungicide dating back to the 1940s. Worldwide emissions have declined steadily over the past forty years, but HCB is still produced as a by-product of a number of industrial processes and is still detected in remote locations around the globe. Many studies have been conducted to determine the toxic and biochemical effects of HCB, but it has been suggested that reported toxic and biochemical effects initially attributed to HCB exposure may have actually been elicited by contamination of HCB by polychlororinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCBs). This thesis investigates whether highly purified HCB (HCB-P; defined as HCB containing < 0.2 ppb of any PCDD, PCDF, or co-planar PCB congener [the detection limit of current analytical methods]) can induce cytochrome P4501A (CYP1A) in three avian species in vitro. Primary cultures of chicken (Gallus gallus domesticus), ring-necked pheasant (Phasianus colchicus) and Japanese quail (Corturnix japonica) embryo hepatocytes were used to compare the potencies of reagent-grade (RG-HCB), HCB-P and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as inducers of ethoxyresorufin O-deethylase (EROD) activity, CYP1A4 messenger ribonucleic acid (mRNA) and CYP1A5 mRNA. The potencies of two mono-ortho substituted PCBs, 2,3,3’,4,4’-pentachlorobiphenyl (PCB 105) and 2,3’,4,4’,5-pentachlorobiphenyl (PCB 118) were also assessed in chicken embryo hepatocytes using the same endpoints. All compounds induced EROD activity and up-regulated CYP1A4/5 mRNAs in the hepatocytes of each species. The potency of HCB relative to the potency of TCDD (ReP) was 0.0001, 0.001 and 0.01 in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes, respectively. ECthreshold values were suggested to be more appropriate than EC50 values because ECthreshold values account for differences in maximal EROD and CYP1A4/5 mRNA levels that are observed with HCB exposure in avian embryo hepatocytes more so than EC50 values. Differences in species sensitivity to HCB were also assessed, and did not vary as greatly as the listed ReP values. The results presented herein suggest that HCB is capable of inducing effects downstream of activation of the aryl hydrocarbon receptor, and may warrant its inclusion in the World Health Organization’s toxic equivalency concept.
5

The Study of Air-Water Exchange of Polycyclic Aromatic Hydrocarbons, Polychlorinated Biphenyls, and Hexachlorobenzene in Kaohsiung Harbor Lagoon

Fang, Meng-der 27 July 2007 (has links)
Estimation of the transport of persistent organic pollutants via air-water exchange requires precise field concentrations from advanced experimental techniques and adequate physic-chemical parameters generated from proper methods. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the ambient air and water column of Kaohsiung Harbor lagoon were measured and used to determine the air-water exchange fluxes of these compounds from December, 2003 to January, 2005. The Whitman¡¦s thin-film model was used by taking temperature and salinity corrected Henry¡¦s law constants into the model to calculate the fluxes. In addition, particulate concentrations and composition in the ambient air and water column were used to apportion PAH sources and dry particle deposition of PAHs, PCBs and HCB. Instantaneous air-water exchange fluxes of PAHs, PCBs and HCB were calculated from twenty-two pairs of air and water samples. The highest net volatile (+3560 ng m-2 day-1) and absorptive (-1230 ng m-2 day-1) PAH fluxes in this study were both obtained from the three-ring PAH, phenanthrene on April 7 and January 27 in 2004, respectively. Differences of flux magnitude and direction between dry and rain season were obvious for PAHs in this study. Most net fluxes of PCB homologues and HCB in this study are from water to air (net volatilization). The highest net volatile flux observed was +172 ng m-2 day-1 (dichlorobiphenyl) in December, 2003 due to elevated wind speed and dissolved concentration, while the only net absorptive flux observed in this study was -0.03 ng m-2 day-1 (dichlorobiphenyl) in January, 2004. Mean daily PAH diffusive fluxes were -727 ng m-2 day-1 influx in dry season but +808 ng m-2 day -1 efflux in rain season and integrated 3.6 kg and 4.0 kg of PAHs were absorbed into and emitted from harbor lagoon surface waters in dry and rain seasons, respectively. The net PCBs and HCB fluxes suggest that the annual sum of 69 PCBs and HCB measured in this study were mainly volatile (57.4 and 28.3 ¡Ñ103 ng m-2 yr-1, respectively) and integrated 1.5 kg and 0.76 kg of PCBs and HCB emitted from harbor lagoon surface waters to ambient atmosphere in the year. Sources apportionment by the isomer ratios, PAHs in the air phase were mainly from grass, wood and coal combustion and some from liquid fuel combustion. Unlike that in air phase, fluoranthene / fluoranthene + pyrene ratios of water phase suggest PAHs were from incomplete-combusted fuel particles emitted from vehicle exhaust. Principal component analysis (PCA) extracted three meaningful PCs for air and water samples, respectively. For the air samples, the three major sources suggested by three sources are vehicular emissions, volatilization to the air from contaminated soil or waters and the coal-burning emission. Among the water samples, the three major sources suggested by three sources are vehicular emissions, oil spill source and coal-burning emission. Air particulate concentrations of PAHs, PCBs and HCB were also used to calculate their dry particle deposition. Throughout our sampling campaigns, PAH dry particle fluxes were quite comparable to fluxes of air-water exchange. On the contrary, PCB and HCB dry particle deposition flux were negligible comparing to their air-water exchange fluxes. Our results suggest PAHs exhibits strong absorptive or weaker volatile fluxes in the dry season but the opposite in the rain season. However, for PCBs and HCB, Kaohsiung Harbor water is potentially an important source to ambient air.
6

Acumulação de compostos organoclorados (PCBs, DDTs e HCB) em tecido hepático de delfinídeos (Cetacea, Mammalia) do Estado do Rio de Janeiro / Organochlorine compounds accumulation (PCBs, DDTs and HCB) in hepatic tissue of delphinids (Cetacea, Mammalia) from Rio de Janeiro State

Leticiaà Nadine Alves Legat 25 February 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / No decorrer das últimas décadas a pesquisa relacionada à contaminação de organismos marinhos por compostos organoclorados (OCs) se intensificou aliada à utilização de algumas espécies como sentinelas da qualidade ambiental quanto aos poluentes orgânicos. Dentre essas espécies, podem-se destacar os cetáceos, animais que entre outras características possuem grande longevidade, alta porcentagem lipídica em seus tecidos e são predadores de topo de cadeia trófica, tendendo assim a acumular altos níveis de OCs em seus tecidos. O presente estudo teve por objetivo determinar as concentrações de OCs de origem industrial e agrícola (PCBs, HCB e DDTs) em tecido hepático de oito diferentes espécies de cetáceos delfinídeos pertencentes a três distintas áreas oceânicas do Estado do Rio de Janeiro, são elas a região costeira, a plataforma continental e a região oceânica. A determinação foi realizada em cromatógrafo a gás (GC - Agilent 6890) conectado a um espectrômetro de massa (MS - Agilent 5973). Os valores de DDTs (1263617272 ng.g -1 lip.) e PCBs (7648877288 ng.g -1 lip.) aqui encontrados estão entre os mais altos já reportados para o táxon. Em todas as áreas observou-se uma predominância do &#931;PCB, seguida do &#931;DDT e HCB, em níveis que refletem o caráter fortemente industrial da região analisada. Entre os PCBs, a maior contribuição advém dos hexabifenis, seguida dos hepta e pentabifenis, sendo os congêneres 153, 138 e 180 os principais em todas as áreas. A razão p,pDDE/&#931;Dp,pDDT foi alta em todas as regiões (0,9), refletindo um input antigo do poluente na área. Foram realizadas correlações entre as concentrações de OCs e os parâmetros biológicos das espécies, como idade, sexo e comprimento total. A transferência placentária de OCs foi analisada em dois pares de fêmea-feto de Sotalia guianensis, mostrando uma maior transferência dos compostos com menor log Kow. Como esperado, foi encontrada uma diferença significativa no perfil de contaminação entre as espécies das diferentes regiões, relacionada à proximidade da fonte, características espécie-específicas e ao arranjo trófico das espécies. / Over the past decades the research on marine organisms contamination by organochlorine compounds (OCs) has been intensified, allied to the utilization of some species as sentinels of the environmental quality related to organic pollutants. Among these species, cetaceans stand out as animals that, between other characteristics, have great longevity, high lipid percentage on their tissues and are top predators in food chains, therefore having the tendency to accumulate high OCs levels in their tissues. The present study aimed to determine OCs concentrations from industrial and agricultural sources (PCBs, HCB and DDTs) in hepatic tissue of eight different species of delphinid cetaceans belonging to three different oceanic areas of Rio de Janeiro State, namely, coastal region, continental shelf and oceanic region. The determination was performed in an Agilent 6890 gas chromatograph (GC) connected to an Agilent 5973 mass spectrometer (MS). DDTs (1263617272 ng.g -1 lip.) and PCBs (7648877288 ng.g -1 lip.) values reported here are amongst the highest values ever reported for the taxon. In all areas &#931;PCB predominance was observed, followed by &#931;DDT and HCB in levels that reflect the highly industrial character of the analyzed region. Amongst PCBs, the largest contribution comes from hexa biphenyls, followed by hepta and penta biphenyls, being the 153, 138 and 180 the main congeners in all areas. The p,pDDE/&#931;Dp,pDDT ratio was high in all regions (0,9), reflecting an ancient input of the pollutant in the area. Correlations between OCs concentrations and biologic parameters such as age, sex and total body lenght were performed. OCs placental transfer was analyzed in two Sotalia guianensis mother-fetus pairs, showing a higher transfer of compounds with lower log Kow. As expected, a significant difference was found on the contamination profile between species from the different regions, related to source proximity, species-specific characteristics and the species trophic arrangement.
7

Acumulação de compostos organoclorados (PCBs, DDTs e HCB) em tecido hepático de delfinídeos (Cetacea, Mammalia) do Estado do Rio de Janeiro / Organochlorine compounds accumulation (PCBs, DDTs and HCB) in hepatic tissue of delphinids (Cetacea, Mammalia) from Rio de Janeiro State

Leticiaà Nadine Alves Legat 25 February 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / No decorrer das últimas décadas a pesquisa relacionada à contaminação de organismos marinhos por compostos organoclorados (OCs) se intensificou aliada à utilização de algumas espécies como sentinelas da qualidade ambiental quanto aos poluentes orgânicos. Dentre essas espécies, podem-se destacar os cetáceos, animais que entre outras características possuem grande longevidade, alta porcentagem lipídica em seus tecidos e são predadores de topo de cadeia trófica, tendendo assim a acumular altos níveis de OCs em seus tecidos. O presente estudo teve por objetivo determinar as concentrações de OCs de origem industrial e agrícola (PCBs, HCB e DDTs) em tecido hepático de oito diferentes espécies de cetáceos delfinídeos pertencentes a três distintas áreas oceânicas do Estado do Rio de Janeiro, são elas a região costeira, a plataforma continental e a região oceânica. A determinação foi realizada em cromatógrafo a gás (GC - Agilent 6890) conectado a um espectrômetro de massa (MS - Agilent 5973). Os valores de DDTs (1263617272 ng.g -1 lip.) e PCBs (7648877288 ng.g -1 lip.) aqui encontrados estão entre os mais altos já reportados para o táxon. Em todas as áreas observou-se uma predominância do &#931;PCB, seguida do &#931;DDT e HCB, em níveis que refletem o caráter fortemente industrial da região analisada. Entre os PCBs, a maior contribuição advém dos hexabifenis, seguida dos hepta e pentabifenis, sendo os congêneres 153, 138 e 180 os principais em todas as áreas. A razão p,pDDE/&#931;Dp,pDDT foi alta em todas as regiões (0,9), refletindo um input antigo do poluente na área. Foram realizadas correlações entre as concentrações de OCs e os parâmetros biológicos das espécies, como idade, sexo e comprimento total. A transferência placentária de OCs foi analisada em dois pares de fêmea-feto de Sotalia guianensis, mostrando uma maior transferência dos compostos com menor log Kow. Como esperado, foi encontrada uma diferença significativa no perfil de contaminação entre as espécies das diferentes regiões, relacionada à proximidade da fonte, características espécie-específicas e ao arranjo trófico das espécies. / Over the past decades the research on marine organisms contamination by organochlorine compounds (OCs) has been intensified, allied to the utilization of some species as sentinels of the environmental quality related to organic pollutants. Among these species, cetaceans stand out as animals that, between other characteristics, have great longevity, high lipid percentage on their tissues and are top predators in food chains, therefore having the tendency to accumulate high OCs levels in their tissues. The present study aimed to determine OCs concentrations from industrial and agricultural sources (PCBs, HCB and DDTs) in hepatic tissue of eight different species of delphinid cetaceans belonging to three different oceanic areas of Rio de Janeiro State, namely, coastal region, continental shelf and oceanic region. The determination was performed in an Agilent 6890 gas chromatograph (GC) connected to an Agilent 5973 mass spectrometer (MS). DDTs (1263617272 ng.g -1 lip.) and PCBs (7648877288 ng.g -1 lip.) values reported here are amongst the highest values ever reported for the taxon. In all areas &#931;PCB predominance was observed, followed by &#931;DDT and HCB in levels that reflect the highly industrial character of the analyzed region. Amongst PCBs, the largest contribution comes from hexa biphenyls, followed by hepta and penta biphenyls, being the 153, 138 and 180 the main congeners in all areas. The p,pDDE/&#931;Dp,pDDT ratio was high in all regions (0,9), reflecting an ancient input of the pollutant in the area. Correlations between OCs concentrations and biologic parameters such as age, sex and total body lenght were performed. OCs placental transfer was analyzed in two Sotalia guianensis mother-fetus pairs, showing a higher transfer of compounds with lower log Kow. As expected, a significant difference was found on the contamination profile between species from the different regions, related to source proximity, species-specific characteristics and the species trophic arrangement.
8

Local and global contaminants in Swedish waters : studies on PCBs, DDTs, 4,5,6-trichloroguaiacol and their transformation products in fish and sediments

Söderström, Maria January 2002 (has links)
This thesis is focused on studies on the environmental fate and methodological improvements for determination of the global contaminants, PCBs and DDTs, and locally discharged phenolics, e.g. 4,5,6-trichloroguaiacol (4,5,6-TCG), and their transformation products. 4,5,6-TCG is released from bleached pulp mills, and was chosen as a model substance, to study its fate and effects in aquatic environments. In a brackish water model ecosystem, 4,5,6-TCG was shown to be transformed via demethylation, dechlorination, and methylation reactions. Marine periphyton exposed to 4,5,6-TCG was shown to form demethylated, brominated and dimeric metabolites. Several of these metabolites were identified and quantified. Also more tightly bound chlorophenolics were recovered from the substrate, after harsh extraction procedures had been applied. Conjugates of chlorophenols in fish bile were determined as useful tracers for monitoring effluents from bleached pulp mills, even in areas far from the discharge point. To facilitate calculations of water concentrations, bile to water bioconcentration factors (bBCF-values) were determined for several phenolics, including also alkali-labile chlorocatechols. PCBs and DDTs, were assessed in Swedish lakes with background exposure of these global contaminants. A methodological study focus on the contamination risks of airborne PCBs, during freeze-drying and storage of dry sediment samples. Eutrophication has been proposed to cause lower levels of pollutants in biota in lakes due to biomass dilution but in this thesis examples of higher levels of PCBs in sediment traps, sediment and in perch, and also in higher fluxes of PCBs to the sediment, were observed. Phytoplankton are supposed to be responsible for most of the transport of the contaminants. The composition of DDTs in soil, sediment traps and in dated sediment cores was studied in some detail. PCBs, DDTs, HCB and HCHs were measured in sediments from 100 reference lakes included in the National Swedish Environmental Program. The lakes have a large variation in lake characteristics, representative for different areas in Sweden. A gradient was observed for sPCB with decreasing levels from the south west towards the north. The results suggests that longrange transport is the dominating mechanism for distribution of the contaminants analysed. In this study the levles of PCBs and DDTs were lower in eutrophic lakes than in oligotrophic lakes, in an area with similar atmospheric exposure. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 6: Manuscript.</p>
9

Improved Assessment in Environmental Monitoring of POPs : Using monitoring data from the aquatic ecosystem and human milk

Nyberg, Elisabeth January 2016 (has links)
The thesis deals with several aspects of monitoring of persistent organic contaminants (POPs) in biological matrices, for example choice of sample, sampling design, and statistical treatment of data both for temporal and spatial trends and for compliance towards a set target value. The efficiency has been evaluated through statistical power analyses. Contaminant data from more than 4 decades from the Swedish National Monitoring Programs for monitoring of contaminants in biota (marine, freshwater and human health), has been quantitatively evaluated both temporally and spatially and for compliance. The aim was also to evaluate the suitability of different matrices, i.e. herring (Clupea harengus), guillemot (Uria aalge) egg, cod (Gadus morhua), perch (Perca fluviatilis), eelpout (Zoarces viviparous), blue mussel (Mytilus edulis), pike (Esox lucius), Arctic char (Salvelinus alpinus) and human milk, for monitoring of POPs with the overall aim to improve the assessment within monitoring programs. The results show that variation can be reduced by using pooled samples including more specimens but fewer chemical analyses, which in turn generate a higher statistical power to a lower cost, at least in cases where the cost of collection and sampling is considerably lower than the cost of chemical analysis. However, there are also a number of advantages using individual samples, such as information of sample variance and maximum value, which allows the choice of an appropriate central measure and direct adjustment of confounding factors. Generally, the levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) have decreased both in marine and freshwater biota but concentrations are still higher in the Baltic compared to e.g. the North Sea. The levels of dioxinlike-PCBs and polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) have decreased in human milk over time, but not to the same extent in fish and guillemot egg from the Baltic and the freshwater environment. This may be explained by the dietary advice developed by the Swedish Food Administration with the goal that girls, reproductive aged, and pregnant women should eat less food containing high levels of PCDD/Fs. Thus the levels in milk could continue to decrease at the same rate although the temporal trend in the environment has slowed down or leveled out. The most essential regarding the choice of species and matrices for contaminant monitoring, is that the species and organ fit the purpose of the monitoring.
10

Eliminació de contaminants orgànics persistents d’oli de peix

Ortiz Almirall, Xavier 15 June 2011 (has links)
En la present tesi doctoral s’han estudiat diversos mètodes per a l’eliminació de contaminants orgànics persistents en olis de peix amb finalitat alimentària. S’han posat al punt les metodologies d’anàlisi necessàries per a la correcta determinació d’aquests compostos en la matriu d’estudi. S’han avaluat amb detall les etapes de purificació de la mostra, fraccionament dels analits i anàlisi instrumental. El mètode ha estat validat amb resultats satisfactoris, i s’ha comprovat el seu bon funcionament a través de la participació en diversos exercicis d’intercalibtage, així com la realització de diversos estudis amb mostres reals d’oli de peix. S’ha estudiat l’eliminació dels contaminants orgànics persistents a través d’adsorbents sòlids amb base silícica i carbonàcia. Les condicions experimentals han estat estudiades més a fons mitjançant dissenys d’experiències, per acabar optimitzant el mètode d’adsorció amb un disseny d’evolució. Els millors resultats s’han obtingut amb el carbó actiu, que mostra una elevada eficàcia en l’eliminació de PCDD/Fs, d-l PCBs i HCB. S’ha estudiat l’eliminació dels contaminants orgànics persistents mitjançant tècniques de degradació fotoquímiques. Inicialment s’ha fotodegradat cada família de contaminants per separat, per poder estudiar més a fons les condicions necessàries per la seva eliminació, així com els seus mecanismes i productes de degradació. Posteriorment s’ha estudiat la fotodegradació simultània dels analits d’interès en oli de peix. Aquesta tècnica s’ha mostrat efectiva en l’eliminació de DDT, PBDEs, HCB i PCBs similars a dioxines. Paral•lelament als estudis d’eliminació mitjançant adsorbents sòlids i tècniques fotoquímiques, s’ha comprovat la qualitat dels olis de peix abans i després del tractament. El procés d’adsorció en sòlids no afecta significativament a la qualitat de l’oli, mentre que les tècniques fotoquímiques degraden una part dels àcids grassos insaturats. S’ha estudiat l’eliminació de contaminants orgànics persistents en oli de peix mitjançant la combinació de les dues tècniques estudiades anteriorment, amb una primera etapa de degradació fotoquímica i una segona etapa d’adsorció. S’han comparat els resultats finals d’eliminació que s’obtenen amb cada un dels mètodes desenvolupats (adsorció, fotodegradació i combinat). L’adsorció en carbó actiu és el procés més adequat per l’eliminació de COPs en oli de peix. S’ha realitzat un estudi dels nivells diastereomèrics i enantiomèrics d’un contaminant emergent -l’hexabromociclododecà (HBCD)- en oli de peix. S’ha avaluat la seva eliminació de la matriu d’estudi mitjançant adsorbents amb base carbonàcia i degradació fotoquímica, sent principalment eliminat per aquesta segona via. / En la presente tesis doctoral se han estudiado diversos métodos para la eliminación de contaminantes orgánicos persistentes en aceites de pescado con finalidad alimentaria. Se han desarrollado los métodos de análisis necesarios para la correcta determinación de estos compuestos en la matriz de estudio. Se han evaluado con detalle las etapas de purificación de la muestra, fraccionamiento de los analitos y análisis instrumental. El método ha sido validado con resultados satisfactorios, y se ha comprobado su buen funcionamiento mediante ejercicios de intercalibraje, así como la realización de diversos estudios con muestras reales de aceite de pescado. Se ha estudiado la eliminación de los contaminantes persistentes mediante adsorbentes sólidos con base silícica y carbonacea. Las condiciones experimentales han estado estudiadas en profundidad mediante diseños de experiencias y de evolución. Los mejores resultados se han obtenido con carbón activo, que demuestra una elevada eficacia en la eliminación de PCDD/Fs, dl-PCBs y HCB. Se ha estudiado la eliminación de los contaminantes orgánicos persistentes mediante técnicas de degradación fotoquímica. Inicialmente se ha fotodegradado cada familia de contaminantes por separado, para poder estudiar más a fondo las condiciones necesarias para su eliminación. Posteriormente se ha estudiado la degradación simultánea de los analitos de interés en aceite de pescado. Esta técnica se ha mostrado efectiva en la eliminación de DDT, PBDEs, HCB y PCBs similares a dioxinas. Paralelamente a los estudios de eliminación mediante adsorbentes sólidos y técnicas fotoquímicas, se ha comprobado la calidad de los aceites de pescado antes y después del tratamiento. El proceso de adsorción en sólidos no afecta significativamente a la calidad del aceite, mientras que las técnicas fotoquímicas degradan una parte de los ácidos grasos insaturados. Se ha estudiado la eliminación de contaminantes orgánicos persistentes en aceites de pescado mediante la combinación de las dos técnicas estudiadas anteriormente, con una primera etapa de degradación fotoquímica y una segunda etapa de adsorción. Se han comparado los resultados finales de eliminación que se obtienen con cada uno de los métodos desarrollados. La adsorción en carbón activo es el proceso más adecuado para la eliminación de COPs en aceite de pescado. Se ha realizado un estudio de los niveles diastereoisoméricos y enantioméricos de un contaminante emergente –HBCD- en aceite de pescado. Se ha evaluado su capacidad de eliminación de la matriz de estudio mediante adsorbentes con base carbonacia y degradación fotoquímica, siendo principalmente eliminado por la segunda vía. / During the present doctoral thesis several methods for the elimination of persistent organic pollutants from fish oil have been studied. Analytical methodologies for the determination of these compounds in fish oil have been developed. Sample purification, fractionation of the analytes and instrumental determination steps have been deeply studied. The method has been validated with satisfactory results, and its performance has been verified through its participation in several intercalibration exercises and studies with real fish oil samples. Elimination of persistent organic pollutants with silicon and carbon-based adsorbents has been studied. The experimental conditions have been studied in depth with an experimental design, to finally optimize the adsorption method using an evolutionary design. Best results have been obtained with the active carbon, showing high efficiency of the removal of PCDD/Fs, dioxin-like PCBs and HCB. Elimination of persistent organic pollutants with photochemical degradation techniques has been studied. Initially, each family of pollutants has been photodegraded separately, to determine its degradation conditions, as well as degradation mechanisms and by-products. Later, simultaneous photodegradation of the analytes has been studied in fish oil. This technique has shown high efficiency on the degradation of DDT, PBDEs, HCB and dioxin-like PCBs. The quality of the oils before and after the treatments with solid adsorbents and photochemical degradation has also been studied. The adsorption process does not significantly affect the quality of the oils, while photochemical techniques can degrade the unsaturated fatty acids. Elimination of persistent organic pollutants in fish oil combining adsorption in solids and photochemical degradation has been studied. Results obtained with each of the developed methodologies (adsorption, photodegradation and combined method) were compared. Adsorption in active carbon is the most suitable process for COPs elimination in fish oil. Finally, diastereoisomeric and enantiomeric levels of an emerging pollutant –hexabromocyclododecane (HBCD)- in fish oil have been studied. Its elimination has been evaluated with carbon-based adsorbents and photochemical degradation, being mainly eliminated with the photodegradation techniques.

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