京都大学 / 新制・課程博士 / 博士(地球環境学) / 甲第23558号 / 地環博第215号 / 新制||地環||41(附属図書館) / 京都大学大学院地球環境学舎地球環境学専攻 / (主査)教授 梶井 克純, 准教授 田中 周平, 准教授 上田 佳代 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第20038号 / 地環博第154号 / 新制||地環||31(附属図書館) / 33134 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 梶井 克純, 准教授 真常 仁志, 准教授 田中 周平 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

Le radical hydroxyle (OH) représente le plus important oxydant dans la troposphère et le puits de la plus grande partie des composés à l’état de trace de l’atmosphère. Si les sources des radicaux hydroxyles sont aujourd’hui relativement bien connues, le terme ‘puits’ des OH, connu sous le terme de réactivité atmosphérique totale avec les radicaux OH (ou réactivité OH) (s-1), reste encore difficile à quantifier. En raison de la complexité des instruments nécessaires, peu de mesures de OH et de réactivité sont actuellement disponibles et la nouvelle méthode proposée par Sinha et al., (2008) représente une alternative prometteuse pour la quantification de la réactivité atmosphérique totale avec les radicaux hydroxyles. Cette méthode est appelée Méthode Comparative de Réactivité (CRM) et est basée sur la mesure rapide d’une molécule normalement absente de l’atmosphère (ici pyrrole, C4H5N) et qui réagit à un taux connu avec les radicaux hydroxyles produits artificiellement dans une petite cellule de réaction en verre. La comparaison des concentrations de pyrrole obtenues en présence/absence d’air ambiant, dans un champ de radicaux constant, permet de quantifier la réactivité de l’air ambiant. Cette thèse a eu pour objectif principal le développement et l’optimisation de cette méthode pour la mesure de réactivité en zone urbaine, fortement riche en monoxyde d’azote (NO), composé identifié comme produisant des artefacts de la mesure. De même, il fallait proposer une méthodologie pour intégrer toutes les corrections, inhérentes à la méthode, à appliquer aux valeurs brutes de réactivité. Une fois la méthode mise au point, le deuxième objectif de ces travaux était la caractérisation de la réactivité atmosphérique totale avec les radicaux OH à Paris, une des rares mégacités existantes en Europe et où aucune mesure de réactivité n’avait été rapportée auparavant. L’étude réalisée pendant la campagne d’hiver 2010 du projet européen MEGAPOLI a permis de caractériser le niveau de réactivité à Paris pendant deux régimes de masses d’air différentes, océanique / continental. Ainsi il a été possible de distinguer un niveau de réactivité purement local de Paris et Ile de France (impacté par le caractère « trafic » de cette ville européenne et étant comparable aux niveaux enregistrés à New York et Tokyo), et un niveau fort, importé, caractéristique d’un transport longue distance. De même, l’étude a révélé que pendant l’import continental, de forts pourcentages ont été enregistrés de réactivité manquante, définie comme la différence entre la valeur mesurée et une valeur théorique, calculée à partir des composés réagissant avec OH et mesurés pendant la campagne. La nature des espèces non-mesurées et contribuant à cette réactivité a été déterminée comme oxydée, issue des processus de « processing » des masses d’air sur le trajet long distance. Ce travail apporte dans un premier temps des informations uniques sur la méthode CRM pour la mesure de la réactivité OH (fonctionnement, traitement des données) et contribue par la suite à la caractérisation des niveaux de réactivité dans la région parisienne. / The hydroxyl radical (OH) represents the most important oxidant of the troposphere and the sink of most trace compounds in the atmosphere. If the sources of the OH radicals are nowadays relatively well constrained, the ‘sink’ term, also known as the total atmospheric reactivity with the OH radicals (or simply OH reactivity) (s-1), is still difficult to quantify. Due to the complexity of the used instruments, only few OH reactivity measurements are currently available. A new method proposed by Sinha et al. (2008) represents a promising alternative to the quantification of the total ambient OH reactivity. This method, also called the Comparative Reactivity Method (CRM), is based on the rapid measurement of a molecule normally not present in the ambient air (here, pyrrole, C4H5N) and which reacts at a known rate with OH radicals artificially generated into a glass reaction cell. Comparing the measured signals of pyrrole with and without ambient air within a constant OH field allows the quantification of the total OH reactivity of the ambient air. The main objective of this PhD work was the development and the improvement of this method for OH reactivity measurements in urban areas, which are abundant in nitrogen oxide (NO), a compound known to produce artifacts in the reactivity measurement. In the same time, it was necessary to propose a methodology to integrate all corrections (inherent to the method) to the raw reactivity data. Once the method adjusted, the second aim of this work was the characterization of the ambient OH reactivity in Paris, one of the few Megacities in Europe and where no other reactivity measurements were previously reported. The study conducted during the 2010 winter campaign of the MEGAPOLI European project allowed to quantify the OH reactivity level in Paris during two different air mass regimes, marine/continental. It was therefore possible to distinguish between a purely local OH reactivity level (about 20s-1) of Paris and Ile de France (impacted by the ‘traffic’ character of this European city and comparable to levels registered in New York and Tokyo) and a high (more than 100 s-1) , imported level characterized by a long distance transport. The study also revealed that during the continental import, high percentages (up to 75%) were registered of the missing OH reactivity, defined as the difference between the measured reactivity and a theoretical value obtained from the reactive compounds measured during the same campaign. The nature of the non-measured species contributing to this missing reactivity was determined as oxidized, issued of the air masses “processed” during the long distance transport. This work brings unique information on the CRM method and contributes to the characterization of the OH reactivity levels in the region of Paris.

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Polychlorinated biphenyls (PCBs) are persistent environmental chemicals. Mono-hydroxylated polychlorinated biphenyls (OH-PCBs) are PCB metabolites found commonly in human blood, environmental water and sediment samples. Detection of small amounts of PCBs and their OH-PCB metabolites in biological matrices from epidemiological and laboratory studies remains a challenge. The application of aptamers is studied as a means to identify and quantify PCBs and OH-PCBs. Aptamers are single stranded short oligonucleotides that arrange into unique shape of three-dimensional structures when binding to their target. Like antibodies they have high affinity and specificity for their specific target. The hypothesis is that aptamers can identify PCBs and PCB metabolites in environmental and biological samples. To test this hypothesis, three different OH-PCBs, 4’-OH-PCB3, 4-OH-PCB72 and 2-OH-PCB106 along with 4-OH-biphenyl as a control, were covalently attached to beads with carboxylic acid groups on their surface. Several methods were explored to characterize covalent binding of OH-PCBs to the beads: FTIR-spectroscopy, Dynamic Light Scattering (DLS) and Zeta-Potential (ZP) measurements. The beads were then used in in vitro assays to test binding of two different aptamers specific to OH-PCBs. In this study, these aptamers were tested for the ability to distinguish structurally different OH-PCB congeners and other environmental pollutants. In future studies, aptamers can be selected for a PCB metabolite of interest, 4’-OH-PCB3, via a modified form of Systemic Evolution of Ligands by Exponential Enrichment (SELEX). Single stranded DNA (ssDNA) aptamers generated will be applied as a biosensor for the detection and quantification of traces of 4’-OH-PCB3.

In this dissertation I compare concentrations of polychlorinated biphenyls (PCBs) and hydroxylated PCBs (OH-PCB) in serum of children and their mothers from urban and rural U.S. communities, determine the variability of these concentrations from year to year, and report the detection of OH-PCBs in sediment from a Lake Michigan waterway and original commercial Aroclors. I developed extraction and analytical methods for the analysis of PCBs and OH-PCBs in 377 human serum samples and 20 sediment samples. I also developed a quality assurance protocol and analyzed more than 300 quality control samples for the purpose of generating an accurate, reproducible, representative, and precise data set. I found that concentrations of PCBs were much higher in mothers than their children, and concentrations of OH-PCBs were slightly higher in mothers than their children. Children were enriched in lower molecular weight PCBs indicating the importance of environmental exposure to their blood concentrations. I also determined that concentrations were similar between the urban and rural residents. These concentrations were similar to concentrations reported in the U.S. general population and other populations without high dietary PCB intake. In East Chicago and Columbus Junction participants, concentrations of OH-PCBs demonstrated a strong positive relationship with PCBs. Variability in PCB and OH-PCB concentration from the first year to the second in most participants exceeded the estimated analytical variability. Observed variability could be due to exposure differences, physiological changes such as metabolism and weight, or a combination. I also discovered the presence of OH-PCBs in the sediment from the Indiana Harbor and Ship Canal (IHSC), a Lake Michigan Waterway. In a first-approach, evidence from analysis of the correlations between OH-PCBs and PCBs in the same sediment is consistent with limited biotic activity. I also report OH-PCBs as contaminants in original commercial Aroclors, and OH-PCB profile similarities between the Aroclors and sediment suggest that Aroclors are the major source of OH-PCB contamination in IHSC. This is a significant finding because OH-PCB contamination of sediment exists anywhere that PCB contamination from Aroclors is present.

<p>The Faroe Islands in the North Atlantic are part of the sub-Arctic region, a remote region far from industrial activity. In spite of this remoteness, the Islands are not a sanctuary: exposures and effects of environmental pollutants mar its natural beauty and wildlife. In the Arctic regions, fish, sea mammals and seabirds have shown to contain elevated levels of the classical persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), as well as more recent POPs such as the polybrominated diphenyl ethers (PBDEs). Human populations living in the Arctic regions are usually highly dependent on seafood and seabirds as food sources, and diet becomes their major source of exposures to POPs. As reported in the 1980’s, residents of the Faroe Islands were shown to have high concentrations of organohalogen substances (OHS) in their breast milk. Long-finned pilot whales (<i>Globicephala melas</i>) blubber and meat have been shown to be a major source of OHS exposure for some of the Faroe Islanders.</p><p>The main objective of this thesis is to investigate the sources and concentrations of some POPs and their metabolites for the Faroese population. First, human milk and serum from pregnant women (mothers) and children were analyzed for PBDEs, PCBs, and polychlorinated biphenylols (OH-PCB), the major PCB metabolites. Second, POPs were measured in seabirds, i.e. PCBs in fulmars (<i>Fulmarus glacialis</i>) and guillemots (<i>Uria algae</i>), and PBDEs in fulmars to search for other potential sources of POPs exposure.</p><p>The results reinforce previous findings that part of the Faroe Island population is highly exposed to OHS. Median concentrations (430 ng/g lipid weight (l.w.) of CB-153) in maternal serum (1994-95) are among the highest in the world. Serum concentrations of CB-153 in children (age 7, samples collected in the early 2000’s) were approximately 90% of those in the mothers, sampled 1994-95. Similarly high CB-153 concentrations (380 ng/g l.w.) were measured in samples of mother’s milk, collected in 1999. The OH-PCB concentrations were also high in segments of the population, with 2.9 ng/g fresh weight as the sum of five OH-PCBs. Except for 4-OH-CB107, concentrations of OH-PCBs were generally lower in children than in mothers.</p><p>The ΣPBDE median concentrations in maternal serum and human milk (1999) are at the higher end of those reported in Europe, with levels of 9.5 and 8.2 ng/g l.w. respectively. ΣPBDE levels increase in human milk samples collected at three different time points (1987-1999), mainly due to increasing BDE-153 concentrations. The range of serum ΣPBDE concentrations in mothers and children are similar, although the congener patterns show differences. BDE-47 is the dominant congener in maternal serum, while BDE-153 is the major congener in children. The differences seen in PBDE congener patterns may arise differences in dates of sampling (7 years) for the two populations, maternal serum sampled in 1994-95 and children serum sampled in 2000-01, rather than from differences in uptake/metabolism or in contemporary exposures.</p><p>PCB concentrations in fulmars and pilot whales show similar ranges. In contrast, PBDE concentrations are 100 times higher in pilot whales than in fulmars. Consequently, Faroese may be especially exposed to PCBs via consumption of fulmars and fulmar eggs, while the exposure to PBDEs is less pronounced.</p><p>Results from this thesis highlight the pronounced exposures to PCBs, OH-PCBs, and PBDEs among residents of the Faroe Islands, a remote region in the Northern Atlantic far away from industrial and urban sources of pollution.</p>

The Faroe Islands in the North Atlantic are part of the sub-Arctic region, a remote region far from industrial activity. In spite of this remoteness, the Islands are not a sanctuary: exposures and effects of environmental pollutants mar its natural beauty and wildlife. In the Arctic regions, fish, sea mammals and seabirds have shown to contain elevated levels of the classical persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), as well as more recent POPs such as the polybrominated diphenyl ethers (PBDEs). Human populations living in the Arctic regions are usually highly dependent on seafood and seabirds as food sources, and diet becomes their major source of exposures to POPs. As reported in the 1980’s, residents of the Faroe Islands were shown to have high concentrations of organohalogen substances (OHS) in their breast milk. Long-finned pilot whales (Globicephala melas) blubber and meat have been shown to be a major source of OHS exposure for some of the Faroe Islanders. The main objective of this thesis is to investigate the sources and concentrations of some POPs and their metabolites for the Faroese population. First, human milk and serum from pregnant women (mothers) and children were analyzed for PBDEs, PCBs, and polychlorinated biphenylols (OH-PCB), the major PCB metabolites. Second, POPs were measured in seabirds, i.e. PCBs in fulmars (Fulmarus glacialis) and guillemots (Uria algae), and PBDEs in fulmars to search for other potential sources of POPs exposure. The results reinforce previous findings that part of the Faroe Island population is highly exposed to OHS. Median concentrations (430 ng/g lipid weight (l.w.) of CB-153) in maternal serum (1994-95) are among the highest in the world. Serum concentrations of CB-153 in children (age 7, samples collected in the early 2000’s) were approximately 90% of those in the mothers, sampled 1994-95. Similarly high CB-153 concentrations (380 ng/g l.w.) were measured in samples of mother’s milk, collected in 1999. The OH-PCB concentrations were also high in segments of the population, with 2.9 ng/g fresh weight as the sum of five OH-PCBs. Except for 4-OH-CB107, concentrations of OH-PCBs were generally lower in children than in mothers. The ΣPBDE median concentrations in maternal serum and human milk (1999) are at the higher end of those reported in Europe, with levels of 9.5 and 8.2 ng/g l.w. respectively. ΣPBDE levels increase in human milk samples collected at three different time points (1987-1999), mainly due to increasing BDE-153 concentrations. The range of serum ΣPBDE concentrations in mothers and children are similar, although the congener patterns show differences. BDE-47 is the dominant congener in maternal serum, while BDE-153 is the major congener in children. The differences seen in PBDE congener patterns may arise differences in dates of sampling (7 years) for the two populations, maternal serum sampled in 1994-95 and children serum sampled in 2000-01, rather than from differences in uptake/metabolism or in contemporary exposures. PCB concentrations in fulmars and pilot whales show similar ranges. In contrast, PBDE concentrations are 100 times higher in pilot whales than in fulmars. Consequently, Faroese may be especially exposed to PCBs via consumption of fulmars and fulmar eggs, while the exposure to PBDEs is less pronounced. Results from this thesis highlight the pronounced exposures to PCBs, OH-PCBs, and PBDEs among residents of the Faroe Islands, a remote region in the Northern Atlantic far away from industrial and urban sources of pollution.