京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18971号 / 工博第4013号 / 新制||工||1618(附属図書館) / 31922 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 田中 宏明, 准教授 藤川 陽子 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

No description available.

BACKGROUND: Perfluorinated compounds (PFCs) have been used as durable water and oil repellent treatments in clothing for more than 50 years. The reason for its popularity is related to the chemical structure, which also makes these compounds persistent in the environment. Numerous studies have shown negative environmental and health effects related to high concentrations of perfluorinated compounds in blood serum. Due to these studies, this paper aimed to find out if perfluorinated compounds could be replaced by non-perfluorinated without compromising performance related to water and oil repellency. METHODOLOGY: A reference sample impregnated with fluorocarbons was compared with the following non-perfluorinated treatments, aliphatic polyurethane (comb polymer) organic silicone and acid (comb polymer) and hydrocarbon (dendrimer). Impregnations were subjected to abrasion, UV-radiation and washing and after each destructive treatment; oil and water repellency tests were conducted. The environmental and health effect of all treatments were examined in a theoretical study. RESULTS: Due to difficulties with the impregnation process, comparable results could only be concluded with the perfluorinated and the hydrocarbon compound. The hydrocarbon was superior the perfluorinated compound to abrasion but for usage simulation methods that allowed chemical reactions, hence UV-radiation and washing, the fluorocarbons showed better resistance. CONCLUSION: Results show that the hydrocarbon treatment could replace perfluorinated treatments commercially when only water and not oil repellency is required. The alternative treatments in this study are not yet sufficiently examined with respect to environmental and health and can therefore not be called greener with certainty. / Program: Textilingenjörsutbildningen

Background: Exposure to perfluorooctane sulfonic acid (PFOS) or to perfluorooctanoic acid (PFOA) increases mouse and human peroxisome proliferator–activated receptor alpha (PPARα) subtype activity, which influences lipid metabolism. Because cholesterol is the substrate from which testosterone is synthesized, exposure to these substances has the potential to alter testosterone concentrations. Objectives: We explored associations of total testosterone and sex hormone–binding globulin (SHBG) concentrations at age 15 years with prenatal exposures to PFOS, PFOA, perfluorohexane sulfonic acid (PFHxS), and perfluoronanoic acid (PFNA) in females. Methods: Prenatal concentrations of the perfluoroalkyl acids (PFAAs) were measured in serum collected from pregnant mothers at enrollment (1991–1992) in the Avon Longitudinal Study of Parents and Children (ALSPAC). The median gestational age when the maternal blood sample was obtained was 16 weeks (interquartile range, 11–28 weeks). Total testosterone and SHBG concentrations were measured in serum obtained from their daughters at 15 years of age. Associations between prenatal PFAAs concentrations and reproductive outcomes were estimated using linear regression models (n = 72). Results: Adjusted total testosterone concentrations were on average 0.18-nmol/L (95% CI: 0.01, 0.35) higher in daughters with prenatal PFOS in the upper concentration tertile compared with daughters with prenatal PFOS in the lower tertile. Adjusted total testosterone concentrations were also higher in daughters with prenatal concentrations of PFOA (β = 0.24; 95% CI: 0.05, 0.43) and PFHxS (β = 0.18; 95% CI: 0.00, 0.35) in the upper tertile compared with daughters with concentrations in the lower tertile. We did not find evidence of associations between PFNA and total testosterone or between any of the PFAAs and SHBG. Conclusions: Our findings were based on a small study sample and should be interpreted with caution. However, they suggest that prenatal exposure to some PFAAs may alter testosterone concentrations in females.

Background: Exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have been associated with higher circulating concentrations of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C). ApoB is the primary apolipoprotein component of LDL-C, and acts as a ligand for LDL-C receptors in various cells throughout the body. Circulating concentrations of ApoB are considered to be a better indicator of heart disease risk than TC or LDL-C. Objectives: Explore associations of concentrations of PFOA and PFOS with serum ApoB in adults. Methods: We analyzed data from 2744, 20-80 years old participants in the 2005–2006 National Health and Nutrition Examination Survey (NHANES). Linear regression models were used to estimate adjusted predicted means of serum ApoB (in g/L) for quartiles of PFOA and PFOS (in ng/mL) to describe patterns of associations. Results: Adjusted predicted mean concentrations of serum ApoB did not appear to vary meaningfully with increasing concentrations of PFOA (Q1 1.11, Q2 1.02, Q3 1.01, Q4 1.02) or increasing concentrations of PFOS (Q1 1.06, Q2 1.05, Q3 1.07, Q4 0.99) in study participants. Conclusions: Exposure to PFOA or PFOS does not appear to alter Apo B concentrations in adults.

A new class of treatment processes called Advanced Reduction Processes (ARP) has been proposed. The ARPs combine activation methods and reducing agents to form highly reactive reducing radicals that degrade oxidized contaminants. Batch screening experiments were conducted to identify effective ARP by applying several combinations of activation methods (ultraviolet light, ultrasound, electron beam, microwaves) and reducing agents (dithionite, sulfite, ferrous iron, sulfide) to degradation of five target contaminants (perchlorate, nitrate, perfluorooctanoic acid, 2,4 dichlorophenol, 1,2 dichloroethane) at 3 pH levels (2.4, 7.0, 11.2). These experiments identified the combination of sulfite activated by ultraviolet light produced by a low pressure mercury vapor lamp as an effective ARP. More detailed kinetic experiments were conducted with nitrate and perchlorate as target compounds and nitrate was found to degrade more rapidly than perchlorate. The effects of pH, sulfite concentration, and light intensity on perchlorate and nitrate degradation were investigated. The effectiveness of the sulfite/UV-L treatment process improved with increasing pH for both perchlorate and nitrate.

No description available.

Les substances perfluoroalkylées (PFAS) sont des composés synthétiques utilisés dans une multitude de domaines pour leurs propriétés hydrofuges, antiadhésives et antitaches exceptionnelles. Cependant, ces contaminants, dont la neurotoxicité a été démontrée dans les études in vitro et in vivo, sont capables de traverser la barrière placentaire et d’atteindre le fœtus en développement. Bien qu’une multitude d’études épidémiologiques aient été conduites pour examiner l’association entre l’exposition prénatale aux PFAS et le neurodéveloppement des enfants, il n’y a pas de consensus dans la littérature : certaines rapportent des associations délétères, et d’autres protectrices ou nulles. Le but de cette étude est d’évaluer l’association entre l’exposition aux PFAS chez les femmes enceintes et le développement neurocomportemental et social des enfants pendant la petite enfance. Nous avons également examiné si le lien différait entre les filles et les garçons. Les données de l’étude Maternal-Infant Research on Environmental Chemicals (MIREC), une cohorte de grossesse pancanadienne, ont été utilisées. L’exposition prénatale à trois PFAS (acides perfluorooctanoïque (PFOA), perfluorooctanesulfonique (PFOS) et perfluorohexane sulfonique (PFHxS)) ainsi que leur somme (ΣPFAS) a été mesurée dans le plasma maternel prélevé durant le premier trimestre de grossesse. Lorsque les enfants étaient âgés de trois-quatre ans, les mères ont été invitées à remplir deux questionnaires sur leurs enfants : le Behaviour Assessment System for Children–2 (BASC-2), pour évaluer les difficultés émotionnelles et comportementales, et le Social Responsiveness Scale–2 (SRS-2), afin d’évaluer le développement social. À partir des données de 794 paires mère-enfant, des analyses de régressions linéaires multiples, avec ajustement pour des facteurs de confusion, ont été réalisées, et les coefficients d’association ont été calculés pour un doublement des concentrations de PFAS. La modification des associations selon le genre a été examinée au moyen de termes d'interaction et d'analyses stratifiées. Bien que la majorité des associations obtenues soient nulles, pour l’ensemble du groupe étudié, un doublement de l’exposition prénatale aux PFOS était lié à moins de déficits de motivation sociale (β = -1.03; IC : -1.88, -0.17) et le PFHxS à plus de comportements atypiques (β = 0.57; 0.04, 1.11). Cependant, les analyses selon le genre ont révélé que chez les garçons seulement, un doublement de l’exposition prénatale aux PFOA était significativement associée à des scores plus faibles pour les sous-échelles suivantes : indice des symptômes comportementaux, problèmes d'externalisation, agressivité et hyperactivité (β allant de -1.87 à -1.32). Le PFOS et la ΣPFAS étaient aussi liés à moins d’agressivité chez les garçons (β = 1.20; -2.27, -0.13 et β = -1.35; -2.55, -0.15 respectivement). À l’inverse, chez les filles, le PFOA était significativement lié à plus de symptômes d’anxiété, et le PFHxS et la ΣPFAS étaient liés à plus de problèmes de cognition sociale (β allant de 0.90 à 1.81). Dans l’ensemble, les données suggèrent que l’association entre l’exposition prénatale aux PFAS et le développement neurocomportemental et social des enfants semble différer selon le genre : un effet protecteur est observé chez les garçons, tandis qu’il ressort délétère chez les filles. Les résultats obtenus dans cette cohorte canadienne de grande taille corroborent ceux notés dans certaines études épidémiologiques rapportant un lien délétère, lequel est surtout observable chez les filles. / Perfluoroalkyl substances (PFAS) are synthetic compounds used in a wide range of fields for their exceptional water-repellent, non-stick, and stain-resistant properties. However, these contaminants, whose neurotoxicity has been demonstrated in in vitro and in vivo studies, can crossthe placental barrier, and reach the developing fetus. Although numerous epidemiological studies have been conducted to examine the association between prenatal exposure to PFAS and the neurodevelopment in children, there is no consensus in the literature: some report deleterious associations, while others report protective or null associations. The aim of this study is to investigate the association between PFAS exposure in pregnant women and the neurobehavioral and social development of children during early childhood. We also examined whether the association differed between girls and boys. We used data from the Maternal-Infant Research on Environmental Chemicals (MIREC) study, a pan-Canadian pregnancy cohort. Prenatal concentrations of three PFAS (perfluorooctanoic (PFOA), perfluorooctanesulfonic (PFOS) and perfluorohexanesulfonic acids (PFHxS)), as well as their sum (åPFAS), were measured in maternal plasma collected during the first trimester of pregnancy. When the children were three to four years old, mothers were asked to complete two questionnaires about their children: the Behaviour Assessment System for Children-2 (BASC-2) to assess emotional and behavioural difficulties, and the Social Responsiveness Scale-2 (SRS-2) to assess social development. Using data from 794 mother-child dyads, multiple linear regression analyses, with adjustment for confounding factors, were performed and regression coefficients were estimated to assess whether there was an association between each doubling of PFAS concentrations and test scores. Effect modification by child gender was examined using interaction terms and stratified analyses. For the entire study group, although most of the associations found were null, a doubling of prenatal PFOS exposure was linked to fewer social motivation deficits (β = -1.03; CI: -1.88, -0.17), and increased PFHxS was linked to more atypical behaviors (β = 0.57; 0.04, 1.11). However, gender-stratified analyses revealed that in boys only, each doubling of prenatal PFOA exposure was significantly associated with lower scores on the following BASC-2 subscales: Behavioral Symptoms Index, Externalizing Problems, Aggressivity and Hyperactivity (β ranging from -1.87 to -1.32). PFOS and åPFAS were also associated with less aggression in boys (β = 1.20; -2.27, -0.13 and β = -1.35; -2.55, -0.15 respectively). Conversely, in girls only, PFOAwas significantly associated with more symptoms of anxiety, and PFHxS and ∑PFAS were associated with more social cognition problems (β ranging from 0.90 to 1.81). Overall, the data suggest that the association between prenatal PFAS exposure and the neurobehavioral and social development of children appears to differ by gender: a protective effect is observed in boys, while a detrimental effect is seen in girls. The results obtained in this large Canadian cohort are consistent with findings from some epidemiological studies reporting a harmful link predominantly in girls.