Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-66).

Thesis (Ph. D.)--Lehigh University, 2005. / Includes vita. Includes bibliographical references (leaves 315-323).

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The investigation of harmful semi volatile organic compounds (SVOC) in the indoor environment is important because on average people spend over 90% of their time indoors. Lindane, an SVOC which was widely used in the UK until 2004, adsorbs to house dust. House dust acts as a reservoir for such contaminants which are remitted by desorption into the air over time. A method for measuring Lindane air concentrations in a vial using SPME without the use of water or any solvent was developed in order to carry out Lindane adsorption and desorption tests. Dynamic tests were carried out to determine adsorption and desorption coefficients as well as equilibrium time. Adsorption and desorption constants (k1 and k2 respectively) were determined by fitting results from the dynamic adsorption tests to an existing two compartment model described in chapter 2, using the statistical analysis software SPSS (vs16). These dynamic tests were carried out for two size fractions (<20µm and >45µm<63µm) and whole dust samples to determine the effect of size fraction on adsorption. For the >45µm to <63µm, k1 = 0.568h-1 and k2 = 0.047h-1, (standard error 0.119 and 0.030 respectively), for the <20µm fraction, k1 = 1.686h-1, k2 = 0.125h-1 (standard error 1.888 and 0.324 respectively), and the whole dust k1= 2.587 h-1, k2= 0.288 h-1 (standard error 0.514 and 0.113 respectively). Static tests were carried out at equilibrium to establish an adsorption isotherm and obtain partition coefficients for different size fractions. The adsorption constants Ka were 4.2 x 10-4mh-1, 7.67 x 10-5mh-1, and 3.03 x 10-3mh-1 respectively. The desorption constants Kd were 0.125h-1, 0.047h-1, 0.288h-1. The partition coefficients Kp were 4.8 x 101µgm-2, 4.08 x 101µgm-2, 1.05 x 102µgm-2, for the <20µm, >45µm<63µm, and whole dust respectively. The higher Kp value for the smaller <20µm fraction compared to the >45µm<63µm fraction, suggests that Lindane adsorbs more strongly to smaller dust size particles. This is significant because it means that the inhalable dust fractions which fall within the <20µm fraction, will have higher concentrations and therefore could potentially be more harmful as the get into the lungs. A possible explanation for the higher Ka value for the whole dust fraction over the two other smaller fractions could be because whole dust is a more complex mixture containing more fibrous substances that may have stronger affinities for Lindane than dust e.g. carpet fibres.

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Les organochlorés (OCs) -molécules utilisées dans des procédés industriels et en applications agricoles dont la plupart sont interdites d'utilisation de nos jours- sont considérés comme des polluants très persistants représentant une menace pour les eaux de surfaces et souterraines, le sol et l'atmosphère. Des méthodes alternatives de décontamination de sites pollués aux OCs sont développées utilisant des technologies in situ d'écoremédiation. L'objectif du projet de thèse est d'étudier les capacités de phytoremédiation des OCs par deux plantes modèles, Zea mays et Phragmites australis. Les OCs choisis dans cette étude sont, le lindane (γHCH), le monochlorobenzène (MCB), le 1,4-dichlorobenzène (DCB) et le 1,2,4-trichlorobenzène (TCB). Notre approche a été de considérer l'impact sur les fonctions physiologiques des plantes de chaque OC en mono-exposition, puis de comparer ces mêmes réponses physiologiques en multi-exposition. Ce travail a permis de mettre en évidence un effet synergique de l'action du mélange des OCs. Toutefois, Z. mays et P. australis tolérent des concentrations OCs largement supérieures aux concentrations environnementales mesurées in situ. La phytoextraction des OCs a été démontrée par nos expériences en conditions contrôlées et en utilisant des molécules 14C-OCs. Les OCs sont majoritairement bioconcentrés au niveau des organes souterrains des plantes. Enfin, cette étude montre une adaptation de la microflore bactérienne de la rhizosphère en présence d'un gradient d'exposition aux OCs (multi-exposition). Les approches d'isolement et d'études d'empreintes moléculaires (ARNr 16S, SSCP, pyroséquançage 454) ont permis de détecter des souches potentiellement capables d'assurer une rhizodégradation des OCs. / Organochlorines (OCs) -molecules used in industrial processes and in agricultural applications which are prohibited from use nowadays- are classified as very persistent pollutants and show an environmental risk for surface water and groundwater, soil and atmosphere. To restore polluted sites, alternative methods are developed using ecoremediation technologies in situ. The aim of this thesis is to study the OCs phytoremediation capacities using two model plants, Zea mays and Phragmites australis. OCs slected for this work are, lindane (γHCH), monochlorobenzene (MCB), 1,4-dichlorobenzene (DCB) and 1,2,4-trichlorobenzene (TCB). The work strategy was to compare the effects on plant physiological functions when plants were exposed to each OC (mono-exposure) and to a mixture of all OCs (multi-exposure). This study highlighted a synergistic effect of the OCs mixture. However, Z. mays and P. australis were able to tolerate OCs mixture concentrations much higher than the environmental concentrations measured in situ. The OCs phytoextraction was demonstrated by our experiments under controlled conditions and using 14C-OCs molecules. OCs were mostly bioconcentrated in the underground parts of the plants. This study also demonstrated an adaptation of the rhizospheric bacterial microflora under a gradient of OCs exposures (multi-exposure). The techniques used (16S rRNA, SSCP, 454 pyrosequencing) held to the detection of strains potentially able to provide OC-rhizodegradation.

Thesis (Ph. D.)--University of Texas Health Science Center at Houston, School of Public Health, 2007. / Source: Dissertation Abstracts International, Volume: 68-12, Section: B, page: 7975. Adviser: Mary Ann Smith. Includes bibliographical references.

O hipertireoidismo leva o fígado a uma situação de proteção antioxidante limítrofe, que pode aumentar a susceptibilidade do órgão a ações deletérias de xenobióticos ou fenômenos que impliquem em estresse oxidativo. Tal ocorre em ratos Sprague-Dawley tratados simultaneamente com hormônio tireoidiano L-3,3\',5-triiodotironina (T3) e o inseticida lindano (gama-hexaclorociclohexano). Enquanto a dose única de lindano (20 mg/kg peso corpóreo) não alterou a maioria dos parâmetros estudados, a administração de T3 estabeleceu a condição de estresse oxidativo hepático pelo aumento da atividade da NADPH-citocromo c redutase, acompanhado do aumento nos índices de lipoperoxidação e da produção microssomal de ânion superóxido (O2-) e da diminuição da atividade de defesas antioxidantes enzimáticas (superóxido dismutase e catalase) e não-enzimáticas (diminuição dos níveis hepáticos de alfa-tocoferol, beta-caroteno e licopeno). A administração de lindano teve seu efeito potenciado pelo hipertireoidismo, como indicado pelo aumento das razões O2-/SOD e SRAT/GSHT e pela diminuição dos níveis de alfa-tocoferol hepático, ambos efeitos maiores do que a soma dos obtidos nos tratamentos isolados. Devido à importância da atividade dos macrófagos residentes no fígado, observada em vários modelos de dano hepático, a função das células de Kupffer (CK) foi estudada neste modelo. Ao contrário do observado em experimentos no fígado íntegro, a luminescência das CK isoladas sofreu decréscimo nos animais tratados com T3 e lindano separadamente, apresentando uma tendência ao aumento no tratamento conjunto. Todos os tratamentos diminuíram a atividade fungicida das CK. É possível que os tratamentos utilizados estejam prejudicando a ação das CK, sendo restaurada na presença dos dois tratamentos. Por outro lado, a importância das CK no aumento do efeito do lindano no hipertireoidismo experimental foi evidenciada pela supressão dos efeitos acima mencionados após a administração do inativador de CK, o GdCl3. Estudos morfológicos corroboram este dado, mostrando uma supressão de sinais inflamatórios e necróticos nos animais hipertiroídeos tratados com GdCl3. / Hyperthyroidism elicits a borderline antioxidant protection state in the liver, which may increase its susceptibility to deleterious effects of xenobiotics or situations that cause oxidative stress. This happens to Sprague-Dawley rats treated concurrently with thyroid hormone L-3,3\',5-triiodothyronine (T3) and the pesticide lindane (gama-hexachlorocyclohexane). While a single dose of 20 mg/kg body weight of lindane did not alter most of the assessed parameters, T3 administration established a hepatic oxidative stress condition by means of an increase in NADPH-cytochrome c reductase activity, with a concomitant increase in lipoperoxidation (increase of thiobarbituric acid reactants) and microsomal generation of superoxide anion (O2-) and lower enzymatic (decreased activities of superoxide dismutase (SOD) and catalase) and non-enzymatic antioxidant defenses (decreased hepatic levels of alpha-tocopherol, beta-carotene, and lycopene). Lindane administration had potentiated effects on hyperthyroid animals, as indicated by the increased O2-/SOD ratio and further lowering of alpha-tocopherol levels in the liver; both effects greater than the sum of the ones observed after isolated treatments. As liver resident macrophages have been shown to play an important role in several hepatic damage models, Kupffer cell (KC) function was also studied in this model. Contrary to what was observed in experiments in the whole liver, Kupffer cell (KC) luminescence was diminished in separately T3 and lindane treated rats, revealing a tendency to increase after joint treatment. All treatments decreased KC fungicidal activity. It is possible that the separate treatments impair KC function, which is restored after the joint treatment. KC role in the potentiation of lindane-induced oxidative stress was evidenced by the suppression of this effect after KC inactivator, gadolinium chloride, administration. Morphological aspects of liver corroborate these data, showing a suppression of inflammatory and necrotic signals, present in hyperthyroid animals treated with lindane.