Os ésteres de ácido ftálico são utilizados como aditivos na manufatura de plásticos e a contaminação do meio ambiente por esses compostos pode ocorrer por diferentes mecanismos. Dado o efeito destes no sistema endócrino de animais e seres humanos, efluentes contendo esses compostos sintéticos devem ser adequadamente tratados antes de qualquer descarte. Os tratamentos convencionais são ineficientes para tratar efluentes aquosos contendo esses ésteres e a oxidação eletroquímica tem sido utilizada como uma opção viável. Assim, neste trabalho foi estudada a degradação eletroquímica de dimetil ftalato (DMFt) utilizando três tipos de ânodos: Ti/Ru0.3Ti0.7O2, F-β-PbO2 e diamante dopado com boro (DDB). Os experimentos foram conduzidos em condições galvanostáticas em células de compartimento do tipo filtro-prensa e vários parâmetros, tais como, eletrólito suporte e a densidade de corrente, foram avaliados. Durante as eletro-oxidações, alíquotas das soluções foram analisadas cromatograficamente e por determinações de carbono orgânico total (COT) e demanda química de oxigênio (DQO). Quando utilizado o ânodo de Ti/Ru0.3Ti0.7O2, foram observados níveis de combustão próximos a 100% em baixos valores de carga elétrica aplicada, indicando um possível processo de incineração direta. Com a incidência de radiação UV incidindo diretamente na superfície do eletrodo, foi obtida a completa remoção de DMFt e 98 % de mineralização em meio ácido, elevadas concentração de cloreto e temperatura. A limitação de ambos os processos foi o transporte de massa e assim, os melhores resultados foram obtidos a baixas densidades de corrente. Com o uso do ânodo de β-PbO2 a remoção de DMFt foi superior na presença de Na2SO4 e em baixas densidades de corrente, com 40 % de mineralização. Com o ânodo de DDB foram realizadas eletro-oxidações na ausência e na presença de radiação UV e ultrassônica. Foi obtida a completa remoção de DMFt, COT e DQO em todas as condições estudadas, com maior eficiência a baixas densidades de corrente, devido a menor limitação por transferência de massa. Ocorreu um efeito positivo na eletrooxidação com aplicação conjunta das duas radiações, no entanto, menor do que o obtido com a aplicação destes processos separadamente. O mecanismo de degradação proposto apresenta a oxidação de DMFt seguida da remoção de grupos metil éster e a quebra do anel aromático para formar ácidos carboxílicos, os quais são mineralizados a dióxido de carbono. Na presença de cloreto, a produção de clorofenóis e ácido tartárico e o aumento na concentração dos intermediários formados são as principais diferenças observadas. / The phthalic acid esters are used as additives in plastics manufacturing and the environmental contamination by these compounds may occur by different mechanisms. Considering its effect on the endocrine system of animals and humans beings, effluents containing these synthetic compounds must be properly treated before any disposal. Traditional methods present limited efficiency for treating wastewater containing these esters and electrochemical oxidation has been proposed as a viable option. In this work, the electrochemical degradation of dimethyl phthalate (DMFt) using three types of anodes: Ti/Ru0.3Ti0.7O2, β-PbO2,F and boron-doped diamond (BDD) was studied. The experiments were performed under galvanostatic conditions using a one compartment filter-press cell and different parameters, such as, electrolyte and current density, were analyzed. During the electro-oxidations, aliquots of the solutions extracted at diffent times were analyzed by liquid chromatography and by variations of total organic carbon (TOC) and chemical oxygen demand (COD). Using Ti/Ru0.3Ti0.7O2 anode, the combustion levels were almost 100% when low values of electrical charge were applied, indicating a possible direct incineration process. Applying UV radiation to the electrode surface, the complete removal of DMFt and 98% mineralization were obtained in acid medium with relative high chloride concentration. Both processes were limited by mass transport and therefore, the best results were obtained at low current densities. Using β-PbO2 anode, the removal of DMFt was higher with 40% of mineralization in the presence of Na2SO4 and at low current densities. Using DDB anode, the electrooxidations were performed in the absence and presence of UV and ultrasonic radiations. The complete removal of DMFT, TOC and COD was obtained for all conditions studied with greater efficiency at low current densities because the smallest mass transfer limitation. A positive effect on the electro-oxidation was observed when UV and ultrasound radiation were applied simultaneously however, lower than that obtained with the application of the processes separately. The degradation mechanism proposed presents the oxidation of DMFt followed by removal of methyl ester groups and breakage of the aromatic ring to form carboxylic acids, which are mineralized to carbon dioxide. In the presence of chloride, the production of chlorophenol and tartaric acid and the increased concentration of the intermediates formed are the majors differences observed.

Os ésteres de ácido ftálico são utilizados como aditivos na manufatura de plásticos e a contaminação do meio ambiente por esses compostos pode ocorrer por diferentes mecanismos. Dado o efeito destes no sistema endócrino de animais e seres humanos, efluentes contendo esses compostos sintéticos devem ser adequadamente tratados antes de qualquer descarte. Os tratamentos convencionais são ineficientes para tratar efluentes aquosos contendo esses ésteres e a oxidação eletroquímica tem sido utilizada como uma opção viável. Assim, neste trabalho foi estudada a degradação eletroquímica de dimetil ftalato (DMFt) utilizando três tipos de ânodos: Ti/Ru0.3Ti0.7O2, F-β-PbO2 e diamante dopado com boro (DDB). Os experimentos foram conduzidos em condições galvanostáticas em células de compartimento do tipo filtro-prensa e vários parâmetros, tais como, eletrólito suporte e a densidade de corrente, foram avaliados. Durante as eletro-oxidações, alíquotas das soluções foram analisadas cromatograficamente e por determinações de carbono orgânico total (COT) e demanda química de oxigênio (DQO). Quando utilizado o ânodo de Ti/Ru0.3Ti0.7O2, foram observados níveis de combustão próximos a 100% em baixos valores de carga elétrica aplicada, indicando um possível processo de incineração direta. Com a incidência de radiação UV incidindo diretamente na superfície do eletrodo, foi obtida a completa remoção de DMFt e 98 % de mineralização em meio ácido, elevadas concentração de cloreto e temperatura. A limitação de ambos os processos foi o transporte de massa e assim, os melhores resultados foram obtidos a baixas densidades de corrente. Com o uso do ânodo de β-PbO2 a remoção de DMFt foi superior na presença de Na2SO4 e em baixas densidades de corrente, com 40 % de mineralização. Com o ânodo de DDB foram realizadas eletro-oxidações na ausência e na presença de radiação UV e ultrassônica. Foi obtida a completa remoção de DMFt, COT e DQO em todas as condições estudadas, com maior eficiência a baixas densidades de corrente, devido a menor limitação por transferência de massa. Ocorreu um efeito positivo na eletrooxidação com aplicação conjunta das duas radiações, no entanto, menor do que o obtido com a aplicação destes processos separadamente. O mecanismo de degradação proposto apresenta a oxidação de DMFt seguida da remoção de grupos metil éster e a quebra do anel aromático para formar ácidos carboxílicos, os quais são mineralizados a dióxido de carbono. Na presença de cloreto, a produção de clorofenóis e ácido tartárico e o aumento na concentração dos intermediários formados são as principais diferenças observadas. / The phthalic acid esters are used as additives in plastics manufacturing and the environmental contamination by these compounds may occur by different mechanisms. Considering its effect on the endocrine system of animals and humans beings, effluents containing these synthetic compounds must be properly treated before any disposal. Traditional methods present limited efficiency for treating wastewater containing these esters and electrochemical oxidation has been proposed as a viable option. In this work, the electrochemical degradation of dimethyl phthalate (DMFt) using three types of anodes: Ti/Ru0.3Ti0.7O2, β-PbO2,F and boron-doped diamond (BDD) was studied. The experiments were performed under galvanostatic conditions using a one compartment filter-press cell and different parameters, such as, electrolyte and current density, were analyzed. During the electro-oxidations, aliquots of the solutions extracted at diffent times were analyzed by liquid chromatography and by variations of total organic carbon (TOC) and chemical oxygen demand (COD). Using Ti/Ru0.3Ti0.7O2 anode, the combustion levels were almost 100% when low values of electrical charge were applied, indicating a possible direct incineration process. Applying UV radiation to the electrode surface, the complete removal of DMFt and 98% mineralization were obtained in acid medium with relative high chloride concentration. Both processes were limited by mass transport and therefore, the best results were obtained at low current densities. Using β-PbO2 anode, the removal of DMFt was higher with 40% of mineralization in the presence of Na2SO4 and at low current densities. Using DDB anode, the electrooxidations were performed in the absence and presence of UV and ultrasonic radiations. The complete removal of DMFT, TOC and COD was obtained for all conditions studied with greater efficiency at low current densities because the smallest mass transfer limitation. A positive effect on the electro-oxidation was observed when UV and ultrasound radiation were applied simultaneously however, lower than that obtained with the application of the processes separately. The degradation mechanism proposed presents the oxidation of DMFt followed by removal of methyl ester groups and breakage of the aromatic ring to form carboxylic acids, which are mineralized to carbon dioxide. In the presence of chloride, the production of chlorophenol and tartaric acid and the increased concentration of the intermediates formed are the majors differences observed.

Les polysaccharides sont l'une des principales options à retenir pour progresser dans l'utilisation ou la conception de polymères renouvelables. Depuis les années cinquante, le développement industriel de ce type de polymères s'était considérablement réduit du fait de l'avènement des polymères synthétiques. Cependant, cet intérêt a cru considérablement ces dernières années en raison de la sensibilisation du public sur la limite des ressources fossiles. Ces biopolymères sont donc devenus un sujet d'importance, tant sur le plan industriel que sur celui de la recherche fondamentale. Toutefois, les systèmes à base de polysaccharides sont le plus souvent transformés via l'utilisation d'importantes quantités de solvants (y compris l'eau), ce qui globalement pénalise le procédé associé en l'affligeant d'une charge environnementale supplémentaire. Par la voie ‘fondue', le développement de polymères thermoplastiques à base de dérivés de la cellulose est un véritable défi, qui concerne autant le mode de transformation de ces systèmes que le niveau des propriétés du matériau final. Pour exemple, la température de dégradation de l'acétate de cellulose (CA) (dont le degré de substitution 2,5 est développé par le Groupe Solvay) est si proche de sa température de fusion que son procédé de mise en oeuvre ne peut être envisagé qu'avec l'ajout d'une quantité importante de plastifiants externes (entre 20 et 30 en poids selon le type d'additif). Le comportement d'un mélange CA-plastifiant est principalement régi par un «réseau» de très fortes interactions polaires, dont la force et la densité dépendent de 3 paramètres spécifiques: le degré de substitution de CA, la typologie de plastifiant et la quantité de plastifiant. Pour expliquer les différents mécanismes de plastification, il est donc important pour nous d'étudier et de comprendre les propriétés dynamiques (en ce qui concerne les phénomènes de relaxation) de ce type de systèmes et comment les trois leviers que nous avons identifiés peuvent influencer ou moduler les différentes interactions échangées dans les mélanges / Polysaccharides are one of the main options to the on-going move towards the use of renewable polymers. The industrial interest in this type of polymers drastically shrunk by the advent of synthetic polymers in the fifties, but is currently reviving due to the public awareness on the limit of fossil resources. These biopolymers are nowadays offering a challenging and industrially profitable playground for researchers. However, current polysaccharides based materials are mostly processed with extensive use of solvents (including water) making the total process an environmental burden despite the advantage of the starting material. Development of thermoplastic cellulose-based materials is very challenging regarding both final material properties and polymer processing. The degradation temperature of Cellulose Acetate (CA) (degree of substitution 2.5) is so close to its melting temperature that it can only be processed with a significant amount of external plasticizers (between 20 et 30 wt.% depending on the type of the additive). Behavior of a CA-plasticizer blend is mainly governed by a ‘network’ of high polar interactions, the strength and the density of which clearly depend of 3 specific parameters: the CA’s degree of substitution, the typology of the plasticizer, the amount of plasticizer. In an attempt to explain the different plasticization mechanisms, it is thus of utmost importance for us to study and understand the dynamic properties (regarding the relaxation phenomena) of this kind of systems and how the three levers that we identified can influence or modulate the different interactions exchanged within the blends

The course of polymer film functioning has been a crucial concern in the advent of packaging technology. The thesis project aims towards obtaining an understanding of mechanical properties for a class of these materials, namely LDPE and PET. A constitutive understanding of this behavior in the case of LDPE is acquired through incorporating a plastic stress strain relationship in an iterative approach with focus put on the sensitivity of a few parameters by following a simple linear curve-fit technique in a way that the global as well as the local response are predictable. FE-models also developed in this way are validated with experimental data. An inverse analysis testing validity or usefulness of DIC technique in identifying a material model is done and some discussions are drawn towards this area. A relative numerical study with respect to experimentally obtained global response for tearing of these polymers is done through use of a similar material model developed from tensile tests and the challenges faced in this area have been addressed.

Di-(2-ethylhexyl)-phthalate (DEHP), an ubiquitous environmental contaminant, has been shown to cause adverse effects on glucose homeostasis and insulin sensitivity in epidemiological studies, but the underlying mechanisms are still unknown. We therefore tested the hypothesis that chronic DEHP exposure causes impaired insulin sensitivity, affects body weight, adipose tissue (AT) function and circulating metabolic parameters of obesity resistant 129S6 mice in vivo. An obesity-resistant mouse model was chosen to reduce a potential obesity bias of DEHP effects on metabolic parameters and AT function. The metabolic effects of 10-weeks exposure to DEHP were tested by insulin tolerance tests and quantitative assessment of 183 metabolites in mice. Furthermore, 3T3-L1 cells were cultured with DEHP for two days, differentiated into mature adipocytes in which the effects on insulin stimulated glucose and palmitate uptake, lipid content as well as on mRNA/protein expression of key adipocyte genes were investigated.We observed in female mice that DEHP treatment causes enhanced weight gain, fat mass, impaired insulin tolerance, changes in circulating adiponectin and adipose tissue Pparg, adiponectin and estrogen expression. Serum metabolomics indicated a general increase in phospholipid and carnitine concentrations. In vitro, DEHP treatment increases the proliferation rate and alters glucose uptake in adipocytes. Taken together, DEHP has significant effects on adipose tissue (AT) function and alters specific serum metabolites. Although, DEHP treatment led to significantly impaired insulin tolerance, it did not affect glucose tolerance, HOMA-IR, fasting glucose, insulin or triglyceride serum concentrations. This may suggest that DEHP treatment does not cause impaired glucose metabolism at the whole body level.

Modern indoor environments contain a vast array of contaminating sources. Emissions from these sources produce contaminant concentrations that are substantially higher indoors than outside. Because we spend most of our time indoors, exposure to indoor pollutants may be orders-of-magnitude greater than that experienced outdoors. Phthalate esters have been recognized as major indoor pollutants. They are mainly used as plasticizers to enhance the flexibility of polyvinylchloride (PVC) products, as well as in humectants, emollients, and antifoaming agents. Phthalates are found in a wide range of consumer products including floor and wall coverings, car interior trim, floor tiles, gloves, footwear, insulation on wiring, and artificial leather. Because these phthalate additives are not chemically bound to the polymer matrix, slow emission from the products to the surrounding air or other media usually occurs. Biomonitoring data suggest that over 75% of the U.S. population is exposed to phthalates. The ubiquitous exposure to phthalates is of concern because toxicological investigations have demonstrated considerable adverse health effects of phthalates and their metabolites. Studies have shown that exposure to phthalates results in profound and irreversible changes in the development of the reproductive tract, especially in males, raising the possibility that phthalate exposures could be the leading cause of reproductive disorders in humans. In addition, effects such as increases in prenatal mortality, reduced growth and birth weight, skeletal, visceral, and external malformations are possibly associated with phthalate exposure. Epidemiologic studies in children also show associations between phthalate exposure in the home and the risk of asthma and allergies. Given the ubiquitous nature of phthalates in the environment and the potential for adverse human health impacts, there is a critical need to understand indoor emissions of phthalates and to identify the most important sources and pathways of exposure. In this study, a model that integrates the fundamental mechanisms governing emissions of semi-volatile organic compounds (SVOCs) from polymeric materials and their subsequent interaction with indoor surfaces and airborne particles was developed. The emissions model is consistent with analogous mechanistic models that predict emission of volatile organic compounds (VOCs) from building materials. Reasonable agreement between model predictions and gas-phase di-2-ethylhexyl phthalate (DEHP) concentrations was achieved for data collected in a previously published experimental study that measured emissions of DEHP from vinyl flooring in two very different chambers. The analysis showed that while emissions of highly volatile VOCs are subject to “internal“ control (through the material-phase diffusion coefficient), emissions of the very low volatility SVOCs are subject to “external“– control (through partitioning into the gas phase, the convective mass transfer coefficient, and adsorption onto interior surfaces). Because of the difficulties associated with sampling and analysis of SVOCs, only a few chamber studies quantifying their emissions from building materials and consumer products are available. To more rigorously validate the SVOCs emission model and more completely understand the mechanisms governing the release of phthalate from polymeric building materials, the emission of DEHP from vinyl flooring was studied for up to 140 days in a specially-designed stainless steel chamber. In the duplicate chamber study, the gas-phase concentration in the chamber increased slowly and reached a steady state level of 0.9 µg/m3 after 30 days. By increasing the area of vinyl flooring and decreasing that of the stainless steel surface in the chamber, the time to reach steady state was significantly reduced, compared to the previous study (1 month vs. 5 months). The adsorption isotherm of DEHP on the interior stainless steel chamber surface was explicitly measured using two different methods (solvent extraction and thermal desorption). Strong adsorption of DEHP onto the stainless steel surface was observed and found to follow a simple linear relationship. In addition, parameters measured in the experiments were then applied in the fundamental SVOCs emission model. Good agreement was obtained between the predictions of the model and the gas-phase DEHP chamber concentrations, without resorting to fitting of model parameters. These chamber studies have shown that the tendency of SVOCs to adsorb strongly to interior surfaces has a very strong influence on the emission rate. Compared to the experimental chamber systems, however, the real indoor environment has many other types of surface that will adsorb phthalates to different extents. The emission rate measured in a test chamber may therefore be quite different to the emission rate from the same material in the indoor environment. For this reason, both a two-room model and a more representative three-compartment model were developed successively to estimate the emission rate of DEHP from vinyl flooring, the evolving gas-phase and adsorbed surface concentrations, and human exposures (via inhalation, dermal absorption and oral ingestion of dust) in a realistic indoor environment. Adsorption isotherms for phthalates and plasticizers on interior surfaces, such as carpet, wood, dust and human skin, were derived from previous field and laboratory studies. A subsequent sensitivity analysis revealed that the vinyl flooring source characteristics, as well as mass-transfer coefficients and ventilation rates, are important variables influencing the steady-state DEHP concentration and resulting exposures. A simple uncertainty analysis suggested that residential exposure to DEHP originating from vinyl flooring may fall somewhere between about 5 µg/kg/d and 180 µg/kg/d. The roughly 40-fold range in exposure reveals the inherent difficulty in using biomonitoring results to identify specific sources of exposure in the general population. This research represents the first attempt to explicitly elucidate the fundamental mechanisms governing the release of phthalates from polymeric building materials as well as their subsequent interaction with interior surfaces. The mechanistic models developed can most likely be extended to predict concentration and exposure arising from other sources of phthalates, other sources of other semi-volatile organic compounds (such as biocides and flame retardants), as well as emissions into other environmental media (food, water, saliva, and even blood). The results will be of value to architects, governments, manufacturers, and engineers who wish to specify low-emitting green materials for healthy buildings. It will permit health professionals to identify and control health risks associated with many of the SVOCs used in indoor materials and consumer products in a relatively inexpensive way. / Ph. D.

<p>Uvod: Poslednjih godina u fokusu istraživača je efekat sintetskih jednjenja na endokrini sistem. Estri ftalne kiseline se koriste u procesu plastifikacije, kao industrijski rastvarači, lubrikanti, aditivi u tekstilnoj industriji, u pesticidima, kozmetičkim proizvodima. Raste broj dokaza da je tiroidna žlezda podložna dejstvu endokrinih disruptora. Tiroidni hormoni imaju važnu ulogu u regulaciji rasta, tkivne diferencijacije, energetskog metabolizma, reprodukcije i formiranja centralnog nervnog sistema. Brojna istraživanja ukazala su da ftalati deluju kao EDs. Ciljevi istraživanja: 1. Procena izloženosti populacije mono-etilheksil-ftalatu (MEHP) i mono-etil-ftalatu (MEP). 2. Evaluacija razlika u nivou pokazatelja tirodine funkcije između ftalat pozitivnih i ftalat negativnih ispitanika i između gojaznih i normalno uhranjenih ftalat pozitivnih ispitanika. 3.Utvrđivanje razlika u serumskom nivou leptina gojaznih ispitanika sa i bez pozitivnih ftalatnih metabolita i procena povezanosti leptina sa MEP i MEHP i pokazateljima tiroidne funkcije. Izbor ispitanika i metod rada: Istraživanje je sprovedeno kao studija preseka, obuhvatilo je 201 ispitanika. Ispitanici su podeljeni u grupu MEP/MEHP pozitivnih i negativnih i na podgupe normalno uhranjenih i gojaznih. Od antropometrijskih mera određena je telesna visina, telesna masa, obim struka i indeks telesne mase. Laboratorijske analize: jutarnji uzorak urina za određivanje MEP i MEHP; na&scaron;te uzet uzorka venske krvi za FT4, FT3, TSH i leptin. Statististička analiza sprovedena je na softverskom paketu SPSS. Rezultati: Polovina stanovni&scaron;tva je izložena ftalatima. MEP dovodi do povi&scaron;enja FT4 samo u subpopulaciji gojaznih. Nije utvrđen statistički značajan uticaj MEP na FT3. Kod gojaznih MEP pozitivnih osoba ženskog pola povi&scaron;en je TSH. MEHP uzrokuje sniženje FT4 kod normalno uhranjenih ispitanika, a kod normalno uhranjenih mu&scaron;karaca snižava FT3. Nije utvrđen uticaj MEHP na tirotropin. U gojaznih nije ustanovljen uticaj DEHP i DEP na leptinsku sekreciju.Uočena je tendencija negativne korelacije leptina i FT4 kod gojaznih, dok uticaja na FT3 i TSH nema. Zaključak: Na&scaron;a populacija je u velikoj meri izložena ftalatima. Potvrđeno je da MEP i MEHP imaju uticaj na pojedine indikatore tiroidne funkcije. Ftalati u na&scaron;em istraživanju ne uzrokuju poremećaj leptinske skrecije, a leptin ima blag uticaj jedino na FT4.</p> / <p>Introduction: Effects of synthesized chemicals on endocrine system has been in the focus in the last years. Phthalates are used in plasticization, as industrial solvents, lubricants, textile industry additives, in pesticides and cosmetic products. Evidence for thyroid disruption is growing. Thyroid hormones (TH) have an important role in regulation of growth, tissue differentiation, energy metabolism, reproduction and central nervous system formation. Studies show phthalates can cause endocrine disruption. Aims: 1. Estimation of burden of mono-ethyl phthalate (MEP) and di-2-ethylheksyl phthalate(MEHP) in the population. 2. Evaluation of differences in TH and TSH in MEP/MEHP positive and negative participants, as in obese and lean MEP/MEHP positive participants. 3. Evaluation of differences in leptin in obese MEP/MEHP positive and negative subjects and evaluation of the connection between leptin, MEP, MEHP and thyroid indicators. Patients and methods: This was a cross-sectional study that comprised 201 subjects divided into MEP/MEHP positive and negative group, further subdivided in obese and lean. Anthropometric parameters done: body height, body weight, waist and body mass index. Laboratory tests done: morning urine sample analysis for MEP/MEHP and venous sample analysis for free thyroxine (FT4), free tri-iodothyronine (FT3), thyroid stimulating hormone (TSH) and leptin. Statistical analysis was done in SPSS. Results: Half of subjects were exposed to phthalates. MEP induced an increase in FT4 in obese participants and had no influence on FT3. TSH was increased in obese MEP positive female subjects. MEHP induced a decrease in FT4 in lean participants and a decrease of FT3 in lean males. There was no correlation between MEHP and TSH. Influence of MEP/MEHP on leptin secretion. A tendency for negative correlation between leptin and FT4 was seen. There was no influence of leptin on FT3 and TSH. Conclusion: Our population is greatly exposed to phthalates. MEP and MEHP influence certain thyroid indicators i.e. cause thyroid disruption. Phthalates do not influence leptin secretion in our study. There is a mild effect of leptin on FT4.</p>

Phthalate esters (PEs) belong to a class of organic compounds used as plasticisers in plastic materials such as polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET) and so on, including those used in the food packaging industry. Phthalate plasticisers are not chemically bound to plastic materials and hence, migrate into items such as foodstuffs they house. The study aimed at investigating the prevalence of selected phthalate esters from plastic wrappers into food as well as the presence of food and/or pathogenic microorganisms. Plastic-wrapped cheese, vienna sausages and polony samples purchased from commercial stores in the four regions of Pretoria (Tswane), South Africa, were analysed for the presence of plasticisers; di-2-ethylhexyl adipate (DEHA), di-n-butyl phthalate (DnBP), benzyl-butyl phthalate (BBP), di-butyl phthalate (DBP) and dimethyl phthalate (DMP). Soxhlet extraction using hexane with florisil column cleanup was carried out. Analysis of PEs was by Gas Chromatography-Flame Ionization Detection (GC-FID). Microbiological investigations were performed using standard methods. The concentrations of PEs detected in food samples ranged from below detection limit (bdl) to 4.7003 μg/kg. However, DBP, DMP and BBP were predominantly present with more PEs detected in cheese compared to polony and vienna. In polony samples, DBP levels ranged from 0.0412 to 0.611μg/kg, in cheese, ranged from 0.049 to 0.256 μg/kg and in vienna DBP ranged from 0.074 to 0.209 μg/kg. The phthalate DMP ranged from 0.072 to 4.700 μg/kg in cheese, 0.056 to 0.241 μg/kg in polony and 0.092 to 0.816 μg/kg in vienna. The DEHA detected in cheese and polony was 0.120 μg/kg and 0.075 μg/kg respectively and no DEHA was detected in vienna sausages. For microbiological analysis, the total microbial activity (TMA) ranged from 6.8 x 104 to 1.03 x 108 cfu/g; coliforms ranged from no growth to 2.62 x 106 cfu/g; yeast ranged from no growth to 1.49 x 107 cfu/g; and mould ranged from no growth to 9.2 x 104 cfu/g. The results revealed that microbial activity was high in each sample type but revealed the absence of pathogens. Results revealed incidences of PEs in foods wrapped or packaged in plastics, which gave cause for concern and showed the need for proper monitoring and inspection of the levels of organo-microbial entities in the South African food wrapped in plastic wrappers. / Environmental Sciences / M.Sc. (Environmental Science)

Os &eacute;steres de ftalato (PAEs) s&atilde;o compostos produzidos em grandes quantidades, amplamente utilizados industrialmente como agentes plastificantes. Seus res&iacute;duos s&atilde;o lixiviados pela &aacute;gua tornando-se poluentes org&acirc;nicos persistentes (POPs) no meio ambiente aquoso, al&eacute;m de apresentar caracter&iacute;sticas de interfer&ecirc;ncia end&oacute;crina. O dietil ftalato (DEP) &eacute; frequentemente encontrado nas amostras ambientais, pois possui elevada solubilidade na &aacute;gua e pode ser gerado durante a degrada&ccedil;&atilde;o de outros PAEs. Assim, este trabalho teve como objetivo a degrada&ccedil;&atilde;o do dietil ftalato em meio aquoso por m&eacute;todo eletroqu&iacute;mico utilizando um &acirc;nodo dimensionalmente est&aacute;vel (ADE) comercial representado como Ti/Ru0,3Ti0,7O2 em uma c&eacute;lula do tipo filtro-prensa. As eletr&oacute;lises foram de 120 minutos contendo uma concentra&ccedil;&atilde;o inicial de 100,3 mg L-1 de DEP, pH inicial igual a 3, a temperatura em 25 &deg;C e vaz&atilde;o em 250 mL min-1. Os experimentos foram feitos utilizando planejamento fatorial do tipo 32 com duas r&eacute;plicas no ponto central, apresentando como vari&aacute;veis independentes a densidade de corrente (10, 25 e 40 mA cm-2) e o logaritmo em base 10 da forca i&ocirc;nica do eletr&oacute;lito suporte, NaCl e Na2SO4 (&micro; = 0,05, 0,15 e 0,5 mol L-1), com o intuito de estudar o efeito da densidade de corrente, concentra&ccedil;&atilde;o e natureza do eletr&oacute;lito para determinar a melhor condi&ccedil;&atilde;o de degrada&ccedil;&atilde;o do dietil ftalato. O monitoramento da concentra&ccedil;&atilde;o do DEP foi feito com cromatografia l&iacute;quida de alta efici&ecirc;ncia (CLAE) e a mineraliza&ccedil;&atilde;o foi acompanhada pelas an&aacute;lises de carbono org&acirc;nico total (COT). Foram obtidas maiores porcentagens de remo&ccedil;&atilde;o e mineraliza&ccedil;&atilde;o com uso das maiores densidades de corrente e na presen&ccedil;a de altas concentra&ccedil;&otilde;es de NaCl em compara&ccedil;&atilde;o com Na2SO4. Dessa maneira, se obteve remo&ccedil;&atilde;o de 63,2 % e mineraliza&ccedil;&atilde;o de 63,9 % em solu&ccedil;&atilde;o 0,5 mol L-1 NaCl e densidade de corrente de 40 mA cm-2, enquanto que para Na2SO4 (&micro; = 0,5 mol L-1) e 40 mA cm-2 foi removido 51,3 % e mineralizado 53,0 % de DEP. O mecanismo de degrada&ccedil;&atilde;o de DEP foi determinado em meio de NaCl e Na2SO4, atrav&eacute;s de CLAE-MS nas condi&ccedil;&otilde;es citadas anteriormente, identificando-se os &iacute;ons moleculares de m/z 149 e 177 em ambos eletr&oacute;litos, correspondentes ao anidrido ft&aacute;lico protonado e ao aduto do anidrido ft&aacute;lico com C(2)H(5)(+) respectivamente, &iacute;ons caracter&iacute;sticos da fragmenta&ccedil;&atilde;o do DEP, al&eacute;m do &iacute;on m/z 239 em Na2SO4 correspondente ao dietil 3-hidroxiftalato. A degrada&ccedil;&atilde;o do DEP acontece atrav&eacute;s da cadeia alif&aacute;tica. / Phthalate esters (PAEs) are compounds produced in large amounts industrially widely used as plasticizers. Their waste are leached by water becoming persistent organic pollutants (POPs) in the aqueous environment, besides having endocrine disrupting characteristics. Diethyl phthalate (DEP) is frequently found in environmental samples, it has high solubility in water and can be generated during the degradation of other PAEs. This work studied the degradation of diethyl phthalate in aqueous media by electrochemical method using a commercial dimensionally stable anode (ADE) represented as Ti/Ru0,3Ti0,7O2 in a filter-press flow cell. The electrolysis were carried out during 120 minutes containing an initial concentration of 100.3 mg L-1 DEP, initial pH = 3, temperature at 25 &deg;C and flow rate of 250 ml min-1. The experiments were performed using factorial design 32 with two replicas at the midpoint, with as independent variables the current density (10, 25 and 40 mA cm-2) and the logarithm base 10 of the ionic strength of the electrolyte, NaCl and Na2SO4 (&micro; = 0.05, 0.15 and 0.5 mol L-1), in order to study the effect of current density, concentration and nature of the electrolyte to determine the best diethyl phthalate degradation condition. The monitoring of DEP concentration was made by high-performance liquid chromatography (HPLC) and the mineralization was accompanied by total organic carbon (TOC) analysis. They obtained higher percentages of removal and mineralization with the use of higher current densities and in the presence of high concentrations of NaCl in comparison with Na2SO4. Thus, there was obtained the removal of 63.2 % and 63.9 % mineralization in 0.5 mol L-1 NaCl and current density of 40 mA cm-2, whereas for Na2SO4 (&micro; = 0.5 mol L-1) and 40 mA cm-2 was removed 51.3 % and 53.0% mineralized DEP. The DEP degradation mechanism was determined in NaCl and Na2SO4, by HPLC-MS under the conditions mentioned above, identifying the molecular ion of m/z 149 and 177 on both electrolytes, corresponding to protonated phthalic anhydride and an adduct of phthalic anhydride with C(2)H(5)(+), respectively, characteristic ions of DEP fragmentation, besides the ion m/z 239 over Na2SO4 corresponding to diethyl 3-hydroxyphthalate. The DEP degradation takes place through the aliphatic chain.

Orientador: Wellerson Rodrigo Scarano / Resumo: Citocinas e proteínas quinases são fundamentais para o controle do processo espermatogênico, estando diretamente envolvidas na dinâmica da barreira hematotesticular. Diferentes mecanismos de controle são modulados por receptores como o GPR30, que ativa rapidamente diferentes vias de sinalização, responsáveis pelos processos de proliferação, sobrevivência e morte celular. Os desreguladores endócrinos (DEs) possuem grande afinidade pelo GPR30, além de potencial para ativar vias de estresse oxidativo e a abertura da barreira. Antagonistas funcionais dos DEs, como o Panax ginseng, podem ser protetores contra seus efeitos. Considerando a importância das vias de sinalização que regulam a espermatogênese e a constante exposição ambiental aos DEs a que estamos submetidos, este trabalho objetiva estudar a possível modulação da via não genômica ativada por GPR30 e do estresse oxidativo em células de Sertoli expostas a baixas doses do DE Monobutil Ftalato (MBP) bem como o potencial papel citoprotetor do GIM-1 (metabólito do P. ginseng) sobre essas células. Para tal, as células de Sertoli humanas (HSec) foram mantidas sobre matriz artificial, simulando o ambiente in vivo. A exposição ao MBP e ao GIM-1 foi realizada nos tempos de 30min, 1, 12, e 48 horas, em doses pré-estabelecidas pelo ensaio do MTT (teste de toxicidade) em 4 grupos: controle, MBP, GIM-1 e MBP + GIM-1. A morfologia celular foi avaliada pela coloração com Hematoxilina e Eosina, evidenciando efeitos deletérios do MBP sobre... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cytokines and kinases protein are essential to control the spermatogenic process, being directly involved in the blood-testis barrier control. Activation of these mechanisms is modulated by receptors such as GPR30, which rapidly activates different signaling pathways responsible for proliferation and cell death processes. Endocrine Disruptors (EDs) have high affinity for GPR30, causing oxidative stress and possible barrier rupture. Functional antagonists of EDs, such as Panax ginseng, may be protective against their effects. Considering the importance of the signaling pathways that regulate spermatogenesis and the constant environmental exposure to the EDs to which we are subject, this work aims to study the possible modulation of the non-genomic pathway activated by GPR30 and oxidative stress in Sertoli cells exposed to low doses of the ED Monobutyl Phthalate (MBP) and the possible cytoprotective role of GIM-1 (P. ginseng metabolite) on these pathways. To this end, HSec human lineage cells were maintained on artificial matrix, simulating in vivo environment. Exposure to MBP and GIM-1 was performed at 30 min, 1, 12 and 48 hours at pre-set MTT (toxicity assay) levels in 4 groups: control, MBP, GIM-1 and MBP + GIM-1. Morphology and cell adhesion were evaluated by staining with Hematoxylin and Eosin, evidencing deleterious effects of MBP above cell distribution and adhesion in basement membrane; GIM-1 group was similar to Control and MBP+GIM-1 showed an intermediate aspect. In o... (Complete abstract click electronic access below) / Doutor