Dissertations / Theses on the topic 'PCBs'

Civil Engineering
Ph.D.
Polychlorinated biphenyls (PCBs) are toxic and persistent chemicals that have been largely dispersed into the environment. The biological and abiotic transformations of PCBs often generate hydroxylated derivatives, which have been detected in a variety of environmental samples, including animal tissues and feces, water, and sediments. Because of their toxicity and widespread dispersion in the environment, hydroxylated PCBs (OH-PCBs) are today increasingly considered as a new class of environmental contaminants. Although PCBs are known to be susceptible to microbial degradation under both aerobic and anaerobic conditions, bacterial degradation of OH-PCBs has received little attention. The overall objective of this study is therefore to evaluate the transformation of mono-hydroxylated PCBs by the well characterized aerobic PCB-degrading bacterium, Burkholderia xenovorans LB400. In order to achieve our overall objective, a series of model mono-hydroxylated PCBs have been selected and they are used to determine the toxicity of hydroxylated congeners toward the bacterium B. xenovorans LB400. The biodegradation kinetics and metabolic pathways of the selected OH-PCBs by B. xenovorans LB400 are then characterized using GC/MS. To understand further the molecular basis of the metabolism of OH-PCBs by B. xenovorans LB400, gene expression analyses are conducted using reverse-transcription real-time (quantitative) polymerase chain reaction (RT-qPCR) and microarray technology. More formally, the specific aims of the proposed research are stated as follows: (1) To evaluate the toxicity of selected mono-hydroxylated derivatives of lesser-chlorinated PCBs toward the bacterium B. xenovorans LB400. (2) To assess the degradation of the selected OH-PCBs by B. xenovorans LB400. (3) To gain further understanding of the molecular bases of the metabolism of the selected OH-PCBs by B. xenovorans LB400. Three hydroxylated derivatives of 4-chlorobiphenyl and 2,5-dichlorobiphenyl, including 2'-hydroxy-, 3'-hydroxy-, and 4'-hydroxy- congeners, were significantly transformed by Burkholderia xenovorans LB400 when the bacterium was growing on biphenyl (biphenyl pathway-inducing conditions). On the contrary, only 2'-OH-4-chlorobiphenyl and 2'-OH-2,5-dichlorobiphenyl were transformed by the bacterium growing on succinate (conditions non-inductive of the biphenyl pathway). Gene expression analyses showed that only exposure to 2'-OH-4-chlorobiphenyl and 2'-OH-2,5-dichlorobiphneyl resulted in induction of key genes of the biphenyl pathway, when cells grown on succinate. These observations suggest that 2'OH-PCBs were capable of inducing the genes of biphenyl pathway. These results provide the first evidence that bacteria are able to cometabolize PCB derivatives hydroxylated on the non-chlorinated ring. Genome-wide transcriptional analyses using microarrays showed that 134 genes were differentially expressed in cells exposed to biphenyl, 2,5-dichlorobiphenyl, and 2'-OH-2,5-dichlorobiphneyl as compared to non-exposed cells. A significant proportion of differentially expressed genes were simultaneously expressed or down regulated by exposure to the three target compounds i.e., biphenyl, 2,5-DCB, and 2'-OH-2,5-DCB, which suggests that these structurally similar compounds induce similar transcriptional response of B.xenovorans LB400. Results of this study may have important implications for the natural attenuation of PCBs and fate of OH-PCBs in the environment. The recalcitrance to biodegradation and the high toxicity of some OH-PCBs may provide a partial explanation for the persistence of PCBs in the environment.
Temple University--Theses

This study extends the work we have previously done by reporting on both gas-phase and particulate phase PCB concentrations in Chicago air as well as giving a first report on airborne OH-PCBs in Chicago. Gas phase PCB concentrations ranged from 43.1 pg/m³ to 2250 pg/m³, with an average concentration of 594 pg/m³ ± 445 pg/m³, and exhibited strong temporal trends. Particulate phase PCBs accounted on average for 4.3% of total PCBs in a sample. OH-PCBs were detected in both the gas and particulate phase and exhibit characteristics of either emission sources or atmospheric reactions depending on the congener.

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.

Bifenilas policloradas (PCBs) foram produzidas comercialmente entre 1929 e meados da década de 1980 para propósitos industriais. As mesmas propriedades que despertaram o interesse industrial, tais como: inércia química, alta constante dielétrica, resistência à queima; foram responsáveis pelo espalhamento dos PCBs em todos os compartimentos ambientais, de tal forma que são encontrados em amostras de tecidos adiposos de animais e humanos, leite, sedimentos dentre outras matrizes. Enormes quantidades de PCBs continuam em uso ou estão estocadas a espera de uma destinação final. No presente estudo demonstramos o uso da reação de hidrodescloração catalítica como forma de destruição/destoxificação de bifenilas policloradas. Para tanto, a reação foi estudada em amostras reais de PCBs (óleo dielétrico - Ascarel®), amostras comerciais (Aroclor® 1242 e 1254) e amostra sintética (2,4-diclorobifenila). O estudo se baseia no uso de solventes orgânicos como meio reacional e paládio suportado em carvão ativado como catalisador, devido à sua seletividade para a reação desejada, bem como sua baixa capacidade de hidrogenar compostos aromáticos. xii A condição experimental ótima para a hidrodescloração foi determinada a partir da aplicação de planejamento experimental do tipo Doehlert. Esta condição ótima foi aplicada com sucesso a PCBs contidos em outras matrizes. A cinética da reação é apresentada para o 2,4-diclorobifenila como estudo de caso e uma proposta de mecanismo da reação de hidrodescloração de PCBs é apresentada baseada nos resultados experimentais.
Polychlorinated biphenyls (PCBs) were produced between 1929 and the 1980s for industrial applications. The same properties that make it a chemical of interest for industrial applications, such as: chemical inertness, high dielectric constant, fire resistance; were responsible for the widespreading of PCBs over all enviornmental compartments. They can be found in samples of fat tissues of humans and animals, milk, sediments, among other matrices. Enormous quantities of PCBs are still in use or stocked waiting for a final destination. In the present study, we have shown the use of catalytic hydrodechlorination as an alternative for the destruction/detoxification of polychlorinated biphenyls. For this, the reaction was studied in real samples of PCBs (dielectric oil - Ascarel®), commercial samples (Aroclor® 1242 e 1254) and pure chlorinated biphenyls (2,4-dichlorobiphenyl). The study is based in the use of organic solvents as reactional media and palladium supported in activated carbon as catalyst, due to its selectivity for the desired reaction and to its low capacity to hydrogenate aromatic compounds. xiv The optimal hydrodechlorination condition was determined through the application of a Doehlert experimental planning. This optimal condition was applied with success to PCBs contained in other matrices. The reaction kinetics for 2,4-dichlorobiphenyl was presented as a case study and a mechanistic proposal was presented for the hydrodechlorination of PCBs based on these experimental conditions.

In this thesis, vibration analyses of electronic assemblies that consist of an electronic box, printed circuit board and electronic components are presented. A detailed vibration analysis of a real electronic assembly is performed by finite element methods and vibration tests. Effects of component addition and component modeling are investigated by finite element analysis in detail. Results are compared in order to identify the most efficient, reliable and suitable method depending on the type of problem. Experimental results for the vibration of an electronic box, PCB and components are presented and discussed. Furthermore, an analytical model that represents a printed circuit board and electronic component is suggested for fixed and simply supported boundary conditions of the PCB. Different types of electronic components are modeled analytically to observe different dynamic characteristics. The validity of the analytical model is computationally checked by comparing results with those of finite element solution.

This study investigated the interaction between polychlorinated biphenyls (PCBs) and selenium to explain the mechanism involved that could affect selenium metabolism and its anti-cancer property. PCBs congeners and mixtures were previously found to reduce hepatic Se and Se-dependent glutathione peroxidase activity. I hypothesized that certain PCB congeners affect selenium metabolism in the rat liver resulting in diminished antioxidant capacity of selenoproteins, which could alter the ability of Se to protect against PCBs induced tumor promotion. In the first study, the influence of 3,3,4,4-tetrachlorobiphenyl (PCB 77) on hepatic Se and glutathione peroxidase (GPx1) activity as well as cytochrome P450 1A1 induction was examined by employing a time-course study, which showed that PCB 77 significantly reduced the hepatic selenium level and GPx1 activity and that this effect was influenced by gender. The next study explored how PCB 77 could deplete hepatic selenium by determining selenium concentrations in different tissues, feces and urine. This study demonstrated that PCB-77 decreased hepatic Se by increased excretion of Se in urine but not in feces. Unlike glutathione peroxidase, thioredoxin reductase activity was not affected by PCB 77. The third study investigated the effect of selenium supplementation on the tumor promoting activity of PCB 77 and 2,2,4,4,5,5-hexaclorobiphenyl (PCB 153) using a 2-stage carcinogenesis model. Se supplementation did not diminish the induction of altered hepatic foci by coplanar PCB 77 or ortho-substituted PCB 153. Instead of protection, the number of foci per cubic centimeter and per liver among the PCB-77 treated rats was increased as the selenium dietary level increased. PCB 153 did not show the same selenium dose-response effect; nevertheless, selenium supplementation did not confer protection against foci development. On the other hand, supranutritional selenium reduced the mean focal volume. Supranutritional selenium or PCBs did not affect cell proliferation or thioredoxin reductase activity. Lastly, the use of the Zeeman graphite furnace atomic absorption spectrometry (GFAAS) method and closed microwave digestion technique for selenium determination of biological samples was compared with the neutron activation analysis and fluorometry methods. I found that GFAAS was not as reliable as the other methods.

Saab develops and manufactures Printed Circuit Board (PCB) for airborne applications. Since the cooling supply often is limited and power dissipation is high the thermal performance of the PCBs is an important parameter to evaluate. This thesis is a step in a larger evaluation of the Finite Element Methods (FEM) used for thermal analysis of the cards. The evaluation aims to create greater understanding of the uncertainties in current models and to provide new proposals on how the models can be improved.
SAAB tar fram och tillverkar kretskort för flygande ändamål. Då kylförsörjningen inte sällan är begränsad och effektförlusten hög är kretskortens termiska prestanda en viktig parameter att utvärdera. Detta examensarbete är ett steg i en större utvärdering av de Finita Element Modellerna (FEM) som används vid termisk analys av korten. Utvärderingen syftar till att skapa större förståelse för osäkerheter i nuvarande modeller samt att ge nya förslag på hur modellerna kan förbättras.

Devido à alta toxicidade, a produção e comercialização dos PCBs (Polychlorinated Biphenyls - Bifenilas Policloradas) estão proibidas no mundo todo. Esses compostos foram utilizados principalmente como base de misturas comerciais em óleos dielétricos para transformadores e capacitores. Hoje existem diversas áreas contaminadas com essas substâncias que são de difícil degradação ocasionada pela sua elevada estabilidade térmica e química. Há diversos estudos sobre diferentes técnicas de tratamento de áreas contaminadas por PCBs. A técnica proposta nesse trabalho foi a de oxidação química através do reagente de Fenton. Para isso, foi simulado em laboratório experimentos de tratamento de solo contaminados artificialmente por ascarel (mistura comercial de PCBs). A oxidação foi realizada segundo a técnica do planejamento experimental fatorial de dois níveis e duas variáveis. Manteve-se constante a concentração do contaminante - em torno de 6000 mg de PCB/ kg de solo - e variou-se a concentração de Fe2+ (0,04 a 0,1 mol/L) e H2O2 (2,07 a 4,15 mol/L). Os ensaios foram realizados ainda nos seguintes tempos de reação: 0, 5, 24 e 48 horas. A análise dos dados foi realizada através de cromatografia gasosa acoplada a um espectrômetro de massa - GC/MS. Dos resultados, concluiu-se que o experimento cuja concentração do reagente de Fenton era 4,15 mol/L de H2O2 e 0,04 mol/L de Fe2+, apresentou melhor percentual de remoção, em torno de 76% para o pentaclorobifenila, 67% para o hexaclorobifenila e 72% para o heptaclorobifenila. Além disso, observou-se que, dentro da região experimental estudada, o efeito da concentração de íons ferrosos foi mais significativo do que o causado pela concentração de peróxido de hidrogênio e que o mesmo tem um efeito negativo pois aumentando a concentração dos íons ferrosos diminui-se a remoção dos contaminantes.
Production and trading of polychlorinated biphenyls (PCBs) are prohibited at whole world due to their high toxicity. They were used mainly as dielectric oils for transformers and capacitors. Recently there are many contaminated areas with these compounds. The high thermic and chemistry stability of PCBs are responsible for their hard degradation. Many studies have been conducted about several techniques of soil remediation. The main purpose of this research is to study chemical oxidation using Fenton\'s reagent to soils treatment. It was simulated in laboratory experiments of soil treatment which was artificially contaminated with Ascarel (PCBs commercial mixture). Process oxidation was made according to factorial experimental planning technique of two levels and two variables (22). The contaminant concentration was constant - 6000 mg PCB/ kg soil - and it was varied the Fe2+ concentration (0,04 mol/L to 0,10 mol/L) and H2O2 concentration (2,07 mol/L to 4,15 mol/L). The times reaction of experiments were: 0, 5, 24 and 48 hours. It was used gas chromatography coupled with mass spectrometer - GC/MS. The better result shown removal rate of 76% to pentachlorobiphenyl, 67% to hexachlorobiphenyl and 72% to heptachlorobiphenyl, experimental conditions were Fe2+ concentration of 0,04 mol/L and H2O2 concentration of 4,15 mol/L. Besides it was observed that studied region the concentration effect of ferrous ions was more significant than concentration effect of hydrogen peroxide. The concentration effect of ferrous ions was negative on system because removal rate of contaminants decreases when [Fe2+] increases.

Polychlorinated biphenyls (PCBs) are a group of 209 persistent organic pollutants, whose documented carcinogenic, neurological and respiratory toxicities are expansive and growing. Existing inhalation estimates demonstrate ubiquitous exposure to World Health Organization (WHO) indicator PCBs and limited other PCB congeners in North America and Europe. However, inhalation exposure estimates of most lower-chlorinated congeners are lacking, and continuing release of PCBs from urban areas demands location-specific assessments of PCB exposure in ambient air and contaminated environments. Using paired indoor and outdoor airborne PCB measurements and activity questionnaires from the AESOP Study, we assess congener-specific exposure rates for adolescent children and their mothers in East Chicago, Indiana and Columbus Junction, Iowa. Our cohorts of 129 (EC) and 135 (CJ) and our detection of 202 individual congeners and coelutions allows unprecedented quantification of congener-specific inhalation exposure, which we compare to dietary exposure using Total Diet Survey PCB concentrations. ∑PCB inhalation is greater for children than for their mothers in both locations, and is greater for East Chicago mothers and children than for Columbus Junction mothers and children, respectively. Schools attended by AESOP Study children have higher indoor PCB concentrations than do homes, and contribute to more than half of children's inhalation PCB exposure. Inhalation of the potentially neurotoxic congeners PCB 11, 40/41/71, and 51 was apparent among individuals at each location. Additional, congener-specific and biological inferences are possible via comparison with sera-based PCB concentrations for these cohorts.

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.

Os bifenilos policlorados (PCBs) são compostos organoclorados que apresentam 209 congêneres sendo que alguns deles são muito tóxicos. Foram produzidos por mais de 30 anos sendo utilizados principalmente no setor eletroeletrônico. Devido à legislação brasileira não prever substituição de equipamentos, ainda em funcionamento, que contenham PCBs estes podem tomar-se fontes potenciais de contaminação no ambiente. Neste aspecto a região do Vale do Paraiba, por ter um parque industrial diversificado (químico, eletrônico e mecânico) iniciado na década de 50, pode apresentar essas fontes. O rio Paraíba do Sul é o principal recurso hídrico sendo utilizado para captação de água para abastecimento e também como receptor de efluentes industriais e esgotos domésticos. Nele também é praticada a pesca de subsistência pela população ribeirinha. Devido às características de bioconcentração no fígado de peixe por organoclorados, decidiu-se utilizá-lo como bioindicador. Assim pode ser verificada a presença de PCBs na região avaliando-se os níveis de contaminação que podem colocar em risco as populações ribeirinhas. Na metodologia analítica proposta, foram encontrados de 48 a 159 ng/g de PCBs totais para a traíra e 12 a 34 ng/g de PCBs totais para o mandi. A recuperação alcançada foi na faixa de 50 a 100%. Os valores do limite de detecção para os 13 congêneres estudados se encontraram na faixa de 1 a 3 ng/g. Os congêneres mais genotóxicos (PCB 77 e 126) foram encontrados principalmente na traira com 20 ± 9 ng/g (PCB 77) e 21 ± 3 ng/g (PCB126), enquanto que o mandi apresentou principalmente o PCB 77 com 8 ± 2 ng/g. Estas avaliações são preliminares e necessitam de maiores estudos para se determinar a extensão do grau de contaminação e as possíveis fontes de contaminação por estes compostos.
The chlorinated biphenyls are organochlorinated compound with around 209 congeners some them are very toxic. They were produced during 30 years and used mainly in the eletronic equipment (transformers and capacitors). Brazilian legislation don\'t obligate the substitution of equipaments containing PCBs that are still being used. So this could be a signifincat source of environrnent contamination. The industries have settled the Paraíba Valley since 50\'s that can represent the major source of PCBs. The South Paraíba river main hidric source that has been used caption for water suplly and subsistent fishing. It receives also industrial efluents and domestic sewer. In spite of bioconcentration characteristics of organochIorinated in fishes\'liver, this organ was decided to be used as bioindicator. PCB\' s level can be avaliated indiretly, analysing the exposure of some species of fishes, and arevall contamination around the fish population. From this proposed analytical method total PCBs from traira here found nearly 32 to 143 ng/g in liver and 8 to 26 ng/g in mandi\'s liver. The aproached recuperation were about 50 to 100%, the limit detection for these 13 congeners were around 1 to 3ng/g. The most genotoxic congeners were found in traira (PCB 77 20 ± 9ng/g and PCB 12621 ± 3ng/g) and other hand, it was only in mandi PCB 77 8 ± 2ng/g. These evalutions are preliminar and necessites further studies to determine the extension of contarnination and the possibly source these compound\' s contamination.

New economically viable methods for the detection and removal of organic pollutants from water samples are needed to meet modern safety requirements. Development of techniques to produce antibody fragments in Escherichia coli (E. coli) have provided the opportunity to exploit antibodies as specialised chemicals for affinity detection and removal technologies. The variable heavy and light antibody domains of the anti-paraquat monoclonal antibody PQXB1/2 have been cloned into the single-chain antibody (scAb) expression vector, pBG1. Anti-paraquat scAb (0.1-0.4 mg/L bacterial culture) was expressed in E. coli. Characterisation of scAb by antigen binding profile and competition ELISA showed it to have a sensitivity one order of magnitude below that of the parent monoclonal. ScAb was purified as a monomer or dimer and analysed by HPLC size exclusion chromatography. When immobilised on polystyrene beads the scAb could remove 85% of paraquat-bovine serum albumin conjugate from solution in a single step.

Polychlorinated biphenyls (PCBs) exert a broad range of toxicity via both parent compounds and their metabolites. Our previous study showed that hydroquinone (H2Q) metabolites of PCBs act as cosubstrates for prostaglandin H synthase (PGHS), and are oxidized by this enzyme to corresponding quinones (Q). The goal of this thesis is to illuminate the PGHS-mediated toxicity of lower chlorinated PCBs. It is hypothesized that PGHS catalyzes two sequential one-electron oxidations of PCB-H2Q to semiquinone (SQ), and Q that interact with biomolecules, such as amino acids, glutathione (GSH), protein, and DNA. In addition, the oxidation of H2Q by PGHS results in an elevation of downstream prostaglandin (PG) production in vivo. Employing 4-chlorobiphenyl-2f,5f-hydroquinone (4-CB-2f,5f-H2Q) as a model compound, I found that PGHS-2 catalyzes the one-electron oxidation of 4-CB-2f,5f-H2Q to SQ. An unusual electronically distorted SQ spectrum was observed as a result of the mixture of two different SQ species, a quartet and a doublet. Fate of 4-CB-2f,5f-SQ and/or Q in the presence of biomolecules was further investigated in the next study. 4-CB-2f,5f-SQ/Q reacts readily with the thiol-containing molecules, such as cysteine, and GSH. Oligonucleotides, and DNA did not form a covalent adduct with 4-CB-2f,5f-SQ but preferably stabilized 4-CB-2f,5f-SQ by pi-stacking interaction under the assay conditions. The in vivo study of downstream PG production in rats treated with 4-CB-2f,5f-H2Q revealed that PGE2 was significantly elevated in ratsf kidneys at 24 h post intratracheal instillation. The increased PGE2 production was correlated with an elevation of alveolar macrophages. These findings suggest two possible mechanisms of enhanced PGE2 production: i) 4-CB-2f,5f-H2Q as a cosubstrate for PGHS in kidney, and 2) release of cytokines from macrophages, leading to stimulation of PGE2 production in other tissues but released and accumulated in kidney for excretion. In summary, the toxicity of lower chlorinated PCBs metabolites is potentially mediated by PGHS. Quinones generated from the PGHS metabolic pathway covalently bind to GSH resulting in GSH depletion, and oxidative stress. The intercalation or pi-stacking of SQ in DNA may be implicated in genotoxicity as a result of the change in DNA structure.

Orientadores: Angelo Zanaga Trape, Thomas Manfred Krauss
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-05T19:02:29Z (GMT). No. of bitstreams: 1 Braga_AnaMariaChebleBahia_D.pdf: 1900359 bytes, checksum: 79e7312e2649cd6e41634906f1302f41 (MD5) Previous issue date: 2003
Resumo: O presente estudo é pioneiro no Brasil e ganha relevância tendo em vista as várias possíveis fontes antropogênicas de PCBs, PCDDs e PCDFs ainda não mapeadas, da ocorrência de acidentes com exposição a produtos clorados em populações brasileiras e da presença, de detecção recente, na ração animal aqui produzida e exportada para a Europa. O objetivo principal foi avaliar a exposição da população geral, utilizando-se o leite humano como bioindicador, com vistas a subsidiar ações de prevenção e controle de emissões destes poluentes para o meio ambiente, como forma efetiva de minimizar a exposição humana. Sendo também parte da terceira rodada dos estudos de exposição organizada pela OMS, a metodologia utilizada seguiu seu protocolo já validado. Em cada uma das 10 áreas amostradas, nas diferentes regiões do país, foram coletadas 10 amostras individuais, conformando uma amostra composta que foi enviada para análise no laboratório de referência da OMS na Alemanha. As amostras de leite humano foram coletadas, em sua maioria, em bancos de leite humano integrantes da Rede Nacional de Bancos de Leite Humano, usando critérios pré-definidos para a seleção das mães doadoras. Ao nível mundial, dos 24 países participantes do estudo, as concentrações encontradas no Brasil foram as mais baixas. Propõe-se um programa de monitoramento destas substâncias e outros Poluentes Orgânicos Persistentes em leite humano e em amostras ambientais como ação preventiva e de controle, incrementando o conhecimento a respeito da ocorrência destes compostos no Brasil, para subsidiar o gerenciamento das substâncias químicas e os acordos internacionais como a Convenção de Estocolmo
Abstract: The presented research is pioneer in brazil and its relevance is due to the various unmapped possible anthropogenic sources of PCBs, PCDDs and PCDFs, to the occurrence of accidents with chlorinated products exposing brazilian populations and the recent episode related to the presence of such contaminants in feedstuff exported to europe. The main objective of this study was to evaluate the exposure of the general population considering human milk as good indicator. Moreover, the study may subsidize future preventing actions and emission control of these pollutants to the environment as an effective manner to minimize human exposure. being also part of the third round of exposure studies organized by WHO, the used methodology followed the validated WHO¿s protocol, as well. In each of the ten sampled areas from different brazilian regions, it was collected ten individual samples to form one pooled sample which was sent to the WHO¿s reference laboratory in Germany. Human milk samples were mostly collected from human milk banks which are part of the National Human Milk Bank Network. Donors were selected considering the prior defined eligibility criteria. On worldwide level, the concentrations found in brazil were the lowest among the 24 participant countries. A monitoring program of these substances e others Persistent Organic Pollutants in human milk and environmental samples is proposed as prevention and control actions. Besides extending the knowledge about the occurrence of these compounds in Brazil, the study may subsidize international programs such as the Stockholm Convention and improve the management of chemical substances
Doutorado
Saude Ambiental
Doutor em Saude Coletiva

The polychlorinated biphenyls (PCBs) comprise a group of 209 congeners varying in the number of chlorine atoms and substitution patterns. These compounds tend to be biomagnified in foodwebs and have been shown to induce an array of effects in exposed organisms. The structural characteristics of the PCBs influence their potency as well as mechanism of action. In order to assess the biological potency of these compounds a multi-step quantitative structure-activity relationship (QSAR) procedure was used in the project described in this thesis.

The ultraviolet absorption (UV) spectra were measured for all 209 PCBs, and digitised for use as physico-chemical descriptors. Interpretations of the spectra using principal component analysis (PCA) showed the number of ortho chlorine atoms and para-para substitution patterns to be significant. Additional physico-chemical descriptors were derived from semi-empirical calculations. These included various molecular energies, the ionisation potential, electron affinity, dipole moments, and the internal barrier of rotation. The internal barrier of rotation was especially useful for describing the conformation of the PCBs on a continuous scale.

In total 52 physico-chemical descriptors were compiled and analysed by PCA for the tetra- to hepta-chlorinated congeners. The structural variation within these compounds was condensed into four principal properties derived from a PCA for use as design variables in a statistical design to select congeners representative for these homologue-groups. The 20 selected PCBs have been applied to study structure-specific biochemical responses in a number of bioassays, and to study the biomagnification of the PCBs in various fish species.

QSARs were established using partial least squares projections to latent structures (PLS) for the PCBs potency to inhibit intercellular communication, activate respiratory burst, inhibit dopamine uptake in synaptic vesicles, compete with estradiol for binding to estrogen receptors, and induce cytochrome P4501A (CYP1A) related activities. By the systematic use of the designed set of PCBs the biological potency was screened over the chemical domain of the class of compounds. Further, sub-regions of highly potent PCBs were identified for each response measured. For risk assessment of the PCBs potency to induce dioxin-like activities the predicted induction potencies (PIPs) were calculated. In addition, two sets of PCBs were presented that specifically represent congeners of environmental relevance in combination with predicted potency to induce estrogenic and CYP1A related activities.

Mestrado em Engenharia do Ambiente
Partículas de Ferro à escala nanométrica representam uma nova geração de tecnologias de remediação ambiental que poderão fornecer soluções eficazes para algumas das mais problemáticas ameaças ambientais. As Nanopartículas de Ferro possuem uma grande área superficial e uma elevada superfície de reacção. Outro factor importante é a sua enorme flexibilidade para aplicações in-situ. Pesquisas mostram que as nanopartículas de ferro são muito eficazes na transformação e destruição de uma vasta gama de contaminantes ambientais, como é o caso de solventes orgânicos clorados, pesticidas organoclorados e PCBs. Como relata este trabalho, actualmente existem vários métodos de tratamento de PCBs, mas nenhum está direccionado para o tratamento de solos através da nanotecnologia. Este estudo relata o desenvolvimento de um método prático de análise de PCBs e avalia a reactividade que as nanopartículas de ferro possuem em relação aos contaminantes presentes no solo da Barrinha de Esmoriz. Através da análise efectuada às amostras de solo recolhidas, foi confirmada a presença de PCBs com uma concentração de 0,03 μg/g de solo seco, que de acordo com a legislação portuguesa é um solo classificado como ligeiramente poluído. Ensaios batch demonstraram que as nanopartículas de ferro adquiridas na NANO IRON, s.r.o. promovem a desalogenação rápida e completa dos PCBs presentes na amostra de solo da Barrinha de Esmoriz. ABSTRACT: Iron nanoparticles represent a new generation of environmental remediation technologies that might provide efective solutions to one of the most troublesome environmental threats. The iron nanoparticles posess a great surface area and a high reaction surface. Another important characteristic is it’s amazing flexibility for in-situ applications. Research shows that the iron nanoparticles are very efective at transforming and destroying a wide range of environmental contaminants, such as chlorinated organic solvents, organochlorine pesticides and PCBs. As this study reports, nowadays there are several methods for PCB treatment, but none of them is aiming to the treatment of soils contaminated with PCBs through nanotechnology. This study reports the development of a practical method for PCB analysis and evaluates the reactivity that the iron nanoparticles have towards the contaminants present in the soil of Barrinha de Esmoriz. Through the analysis made to the soil samples collected, the presence of PCBs was detected with a concentration of 0,03 μg/g dried soil, that by the Portuguese Legislation is a soil classified as lightly polluted. Batch trials demonstrate that the iron nanoparticles acquired from NANO IRON, s.r.o., promote the fast and complete dehalogenation of the PCBs present in the soil samples from Barrinha de Esmoriz.

Os PCBs, do inglês Polychlorinated Biphenyls (bifenilas policloradas), é o nome genérico dado à classe de compostos organoclorados resultante da reação do grupo bifenila com cloro anidro na presença de catalisador. São tóxicos, persistentes, bioacumulativos e representam o risco de provocar efeitos nocivos à saúde humana e ao meio ambiente. Grandes quantidades de PCBs foram produzidos em vários países entre 1927 e 1977. Nos Estados Unidos a proibição ocorreu em 1977. Utilizados como fluidos dielétricos em transformadores elétricos e capacitores em todo o mundo, comercialmente conhecidos como Ascarel, dentre outras denominações, tais como Aroclor, Pyralene, Clorophen, Inerteen, Asbestol e Kneclor. Devido à alta toxicidade, a produção e comercialização dos PCBs foram proibidas no mundo todo a partir de 1980. No Brasil, transformadores que tiveram o óleo mineral isolante, contaminado por PCBs, estando em uso ou em armazenamento, segundo os critérios da Norma ABNT NBR 13882, a destinação final do óleo isolante deverá ser feita por incineração e ou descontaminação a valores inferiores a 50mg/kg. Neste trabalho realizado no Instituto de Química de São Carlos - Universidade de São Paulo, desenvolveu-se um procedimento para a descontaminação de óleo contaminado com valor conhecido acima de 50mg/kg, por percolação em coluna contendo espuma de poliuretano derivada de óleo de mamona, produzida pelo Laboratório de Química Analítica e Tecnologia de Polímeros (GQATP), obtendo-se uma redução de 55% dos níveis de PCBs em óleo contaminado. As espumas foram funcionalizadas com tiodiglicol e polissulfeto de amônio, obtendo-se respectivamente 24% e 11% de redução dos níveis de PCBs em óleo contaminado. Observou-se que a espuma de poliuretano produzida pelo GQATP, funciona como um adsorvente eficaz na remoção de PCBs, e que a utilização de n-hexano na dessorção da espuma, permite remover praticamente todos os PCBs adsorvidos. Portanto, esses tipos de espumas podem servir como adsorventes altamente eficazes na remoção dos PCBs presentes nos óleos minerais isolantes e, portanto, contribuir significativamente para a proteção do meio ambiente.
PCBs, (polychlorinated biphenyls), is the generic name given to the class of organochlorine compounds resulting from the reaction of the biphenyl group with anhydrous chlorine in the presence of catalyst. They are toxic, persistent, bioaccumulative and pose the risk of causing harm to human health and the environment. Large quantities of PCBs were produced in several countries between 1927 and 1977. In the United States the prohibition occurred in 1977. Used as dielectric fluids in electrical transformers and capacitors in the world, commercially known as Ascarel, among other names such as Aroclor, Pyralene, Clorophen, Inerteen, and Asbestol Kneclor. Due to high toxicity, production and marketing of PCBs have been banned worldwide since 1980. In Brazil, transformers that had insulating mineral oil, contaminated with PCBs, while in use or in storage, according to the criteria of the Standard NBR 13,882, the final destination of insulating oil should be by incineration or decontamination and the values below 50mg/kg. In a previous work carried out at the Chemistry Institute of Sao Carlos - University of Sao Paulo, a procedure was developed for the decontamination of oil contaminated with known value above 50 mg / kg of percolation column containing polyurethane foam derived from castor oil produced Laboratory of Analytical Chemistry and Technology of Polymers (GQATP), resulting in a 55% reduction in the levels of PCBs in contaminated oil. Foams were functionalized with thiodiglycol and Ammonium polysulfide, yielding respectively 24% and 11% reduction in the levels of PCBs in contaminated oil. It was observed that the polyurethane foam produced by GQATP function as an effective adsorbent for removal of PCBs, and that the use of n-hexane desorption of the foam allows to remove virtually all PCBs adsorbed. So these types of foam can serve as highly efficient adsorbents for the removal of PCBs present in the insulating mineral oil, and thus contribute significantly to environmental protection.

I contaminanti organici persistenti costituiscono un gruppo di sostanze chimiche artificiali strutturalmente tra loro diverse e caratterizzate, quale elemento comune, da un’elevata bio-persistenza e dalla capacità di essere trasportate per lunghe distanze su scala planetaria, lontano dal luogo originario di emissione nell’ambiente. A questa classe di sostanze chimiche appartengono, tra gli altri, i bifenili poli-clorurati, i pesticidi organo-clorurati, tra cui il DDT e i suoi metaboliti, e altri prodotti chimici come le dibenzo-p-diossine e i dibenzo-furani policlorurati. Queste sostanze chimiche sono ormai ampiamente distribuite nell'ambiente, in quanto alcuni di loro sono stati a lungo impiegati in agricoltura e nella sanità pubblica come pesticidi (il DDT e gli altri insetticidi clorurati), altri come prodotti chimici industriali (i bifenili poli–clorurati) e altri sono inevitabili sottoprodotti di processi industriali (le dibenzo-p-diossine e i dibenzo–furani policlorurati). Per le loro caratteristiche tossicologiche, queste sostanze chimiche possono essere fonte di rischio per la salute umana. In Italia si è fatto largo uso di insetticidi della famiglia organo clorurata (DDT e prodotti simili) dagli anni ‘40 agli anni ‘70 del 1900, soprattutto per fini di salute pubblica, per l’eradicazione di vettori (zanzare) della malaria e dei PCB, prodotti in Italia per il settore manifatturiero (produzione di dispositivi elettrici e termici), nella produzione di energia (uso di trasformatori e condensatori) e come materiali industriali in diversi comparti. Ciò nonostante, le informazioni sui livelli di esposizione della popolazione generale rimangono limitate. Questo studio si è proposto di misurare i livelli di alcuni insetticidi organo-clorurati e dei PCB nella popolazione generale italiana in tre luoghi diversi: Novafeltria (un paese del Centro Italia), Pavia (una città di medie dimensioni) e Milano (la seconda città più grande in Italia) e ad esplorare la relazione del loro accumulo nella popolazione con i luoghi di residenza, il sesso, l’età e la costituzione individuale. Per misurare le concentrazioni di PCB, i campioni di sangue sono stati raccolti campioni di sangue da 372 soggetti che hanno fornito il consenso informato e per misurare gli insetticidi organo-clorurati sono stati raccolti i campioni da 137 soggetti. Nel siero sono stati misurati 36 congeneri dei PCB e 8 insetticidi organo-clorurati mediante gas-cromatografia-spettrometria di massa. Per normalizzare le concentrazioni dei PCB e degli insetticidi organo-clorurati alle concentrazioni totali di lipidi nel sangue (una tecnica comunemente impiegata per tener conto del carattere lipofilico dei composti), sono stati misurate le concentrazioni sieriche di trigliceridi e colesterolo totale mediante tecniche standard di chimica clinica. Le informazioni personali quali il sesso, l'età, l'altezza e il peso, le abitudini alimentari, l'istruzione, la residenza e l'occupazione le informazioni sono state raccolte attraverso un questionario. Sono state impiegate analisi statistiche per evidenziare eventuali relazioni dei livelli degli analiti con caratteristiche dei soggetti indagati quali la residenza, l’età, il sesso e l’indice di massa corporea. Le concentrazioni degli analiti sono state indagate in termini sintetici per la popolazione complessiva dei 3 siti, e separatamente per i singoli siti, per sesso, per età e per le categorie di BMI. I PCB congeneri 138, 153 e 180 sono stati quelli più frequentemente rilevati nei campioni e sono risultati quelli maggioritari nel concorrere alla dose totale di PCB. Il PCB 153 ha il più alto livello medio in ciascun sito. Il livello totale di PCB differisce in modo significativo tra questi siti (p < 0,0001) con concentrazioni mediane di 837, 1355 e 2062 pmol/g di lipidi, rispettivamente a Novafeltria, a Pavia e in Milano. Non sono state dimostrate differenze nella distribuzione dei livelli di PCB totali tra i due sessi. La somma dei PCB diossino-simili differiva in modo significativo (p < 0,0001) tra i siti (media 111 e 167 pmol/g di lipidi, rispettivamente) e tra i due sessi a Novafeltria e a Pavia (p = 0,011 e 0,009, rispettivamente). I PCB 138, 153, 170 e 180 differivano in modo significativo tra i luoghi di residenza (p < 0,0001), con valori più elevati nella popolazione di Milano. In generale, nella popolazione totale esaminata i livelli dei PCB totali e dei congeneri 138, 153, 156, 170 e 180 correlano positivamente con l'età (coefficienti r di correlazione compresi tra 0,320 e 0,569, p < 0,0001). A Novafeltria i coefficienti r risultano compresi tra 0,545 e 0,670 e tra 0,516 e 0,666 a Pavia. A Milano, i coefficienti r per le correlazioni con età sono risultati compresi tra 0,327 e 0,417 per i PCB totali e per i congeneri 138, 153 e 180. Ad eccezione del PCB 170 non è stata osservata alcuna differenza significativa nella distribuzione dei più abbondanti congeneri di PCB e PCB totali tra le diverse categorie di BMI (individui ‘più o meno grassi’). Tra gli insetticidi organo-clorurati, il p,p'-DDE e l’HCB contribuiscono in misura magiore al carico corporeo totale per la classe di composti. I loro livelli differiscono in modo significativo tra le tre città, con un trend di Milano > Novafeltria > Pavia (p < 0,0001). Considerando l’intero campione, le femmine hanno concentrazioni significativamente più alte di HCB e p,p'-DDE rispetto ai maschi. Le concentrazioni di HCB sono significativamente più alte nelle femmine rispetto ai maschi di Milano (p = 0,029). Abbiamo osservato correlazioni positive tra la concentrazione di p,p'-DDE e HCB e l’età solo nei soggetti di Novafeltria (r = 0,468, p = 0,004). Considerando l’intera popolazione studiata, le concentrazioni dell’insetticida organo clorurati totali differiscono in modo significativo tra le categorie di BMI (p = 0,018). Abbiamo misurato il pattern dei principali congeneri dei PCB e degli insetticidi organo-clorurati in una campione abbastanza esteso della popolazione italiana. In generale il nostro studio fornisce informazioni sui livelli di esposizione a PCB e ad insetticidi organo-clorurati e fornisce indicazioni per ulteriori indagini.
Persistent Organic Pollutants is a group of structurally diverse man-made chemicals characterized by a high bio-persistence and the ability to travel a long distance on the planetary scale. This class of chemicals includes polychlorinated biphenyls, organochlorinated pesticides such as DDT and its metabolites and other chemicals such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans. These chemicals are widely distributed in the environment as some of them have long been employed in agriculture and in public health as pesticides, others as industrial chemicals and others are unavoidable by-products of industrial processes. These chemicals can be a source of health risk to human. Despite extensive use of OCPs such DDT in Italy in the 1940s to 1970s especially for public health control of malaria mosquitoes and PCBs in industry, in energy production and in industrial commodities, information on their exposure levels among the general population is limited. This study aims at determining the levels of OCPs and of PCB congeners among the residents from Italians living in three different places: Novafeltria (a village in Central Italy), Pavia (a mid-sized town) and Milan (the second-largest city in Italy) and at exploring the relationship with places of residence, gender, age and individual body size of their accumulation in the population. To measure PCBs concentrations, blood samples were collected from 372 consented subjects whereas to measure OCPs blood samples were collected from 137 subjects. Thirty six PCB congeners and eight OCPs were measured in blood serum by gas-chromatography-mass spectrometry. To normalize PCBs and OCPs concentrations to total blood lipid concentrations (a commonly employed technique to take into account the lipophilic character of the compounds), serum concentrations of triglycerides and total cholesterol were measured by standard clinical chemistry techniques. Personal information such as gender, age, height and weight, dietary habits, education, residence and occupation information were collected through a questionnaire. Statistical analyses were employed to highlight variation in analytes levels with respects to residence, age, gender and body mass index. The analytes concentrations were summarized for the overall population of three sites and separately for the individual sites, for gender, for age groups and for BMI categories. The PCB congeners 138, 153 and 180 were the most frequently detected in overall population sample and were the major contributors of total PCB burden. PCB 153 had the highest median level in each site. Total PCB level differed significantly between the study sites (p < 0.0001) with median concentrations of 837, 1355 and 2062 pmol/g lipid, respectively in Novafeltria, Pavia and Milan. No evidence was found for the difference in distribution of total PCB levels by genders. Total DL–PCB differed significantly (p < 0.0001) between the sites (median 110, 51 and 167 pmol/g lipid, respectively) and genders of Novafeltria and Pavia (p = 0.011 and 0.009, respectively). PCB 138, 153, 170 and 180 differed significantly between the sites (p < 0.0001) with higher values in Milan population. In overall population total PCB, PCB 138, 153, 156, 170 and 180 correlated positively with age (r for linear correlations range between 0.320–0.569, p < 0.0001). In Novafeltria the r correlations range between 0.545–0.670 and 0.516–0.666 in Pavia. In Milan, r correlations with age range between 0.327–0.417 for total PCB, congener 138, 153 and 180. With exception of PCB 170 there was no evidence of significant difference in distribution of most abundant PCB congeners and total PCB across the BMI categories. Among the OCPs, p,p'-DDE and HCB were the most abundant and major contributors of total OCP concentration. Their levels differed significantly between the three towns with a trend Milan > Novafeltria > Pavia (p < 0.0001). Females had significantly higher concentrations of HCB and p,p'-DDE than males in overall population sample. HCB concentrations were significantly higher in females than in males of Milan (p = 0.029). We observed positive correlations of p,p'-DDE and HCB with age in Novafeltria subjects (r = 0.468, p = 0.004). Total OCP concentrations differed significantly across BMI categories (p = 0.018) in overall population. We have demonstrated a pattern of distribution of the levels of the main PCB congeners and OCPs in a fairly large population in Italy. Generally our study provides information on PCBs and OCPs exposure among the Italian general population and provides indications for further investigations.

The aim of this thesis is to explore the Schwartz reaction, a method for the catalytic dechlorination of polychlorinated biphenyls (PCBs). Chapter One introduces PCBs, their stability and industrial utility, their subsequent detection in the environment and concerns over their human health effects leading to a political will for remediation 0 of PCB contaminated land. Natural, physical, biological and chemical destruction methods o for PCBs are then reviewed. The chapter concludes by introducing the Schwartz reaction which uses CP2TiCh, NaBH4 and pyridine in diglyme to dechlorinate PCBs. Its advantages and disadvantages are highlighted. Chapter Two studies the mechanism of the Schwartz reaction using a variety of techniques. A DFT study is described, reaction conditions are explored and a proposed intermediate (Cp2TiHpyr) is isolated and characterised with the aid of deuterium labelling. A Schwartz reaction using CP2TiHpyr is carried out in an EPR tube, conclusions are drawn about the Ti(III) species present therein and a modified mechanism is proposed. Chapter Three tests a variety ofnew catalysts for dechlorination ofPCBs. The original CP2TiCh catalyst is altered by variation of the ligands and the metal and other new systems containing an '(Tl-arene)FeCp' moiety are tested. New catalytic systems are presented including precursor compounds which are air and moisture stable. Chapter Four investigates the removal of toxic pyridine as a requirement for the Schwartz reaction. Alternative bases are tested and conclusions drawn about the role of the base in the mechanism. Transition metal complexes are then prepared which incorporate an amine (NMe2 or NtBu) or pyridine functionalised arm into the ligand framework. lIB NMR spectroscopy is used to observe the amine'BH3 adducts present in the reaction mixture and provide new insights into the reaction mechanism. Chapter Five explores heterogenisation of the Schwartz reaction by synthesising a range of titanocene functionalised polystyrenes. These are characterised using solid state IH NMR (MAS), TGA and EDX. These solids are then tested for their catalytic activity. Experimental procedures are documented in Chapter Six and characterising data for all new or previously uncharacterised compounds are given in Chapter Seven. Asummary of all catalytic data from Schwartz reactions in this thesis is given in Appendix One. DFT, EPR and crystal structure data are given in the Electronic Appendix.

For the needs of the present master thesis, a Pick & Place machine for through-holecomponents with insight in three axes was studied and implemented. What motivatedthis endeavour was the trend to increasingly automated production lines in theelectronics manufacturing industry. Certain through-hole elements require furthermodifications, such as the screwing of heatsinks on them post the placing andsoldering.That implies that a certain distance from the board is ensured when placing andsoldering the components, which involves further manual labour for securing thecomponents at the desired height until they are soldered, thus increasing the cost andlowering the productivity. Therefore, the resulting system that was developed, placesthrough-hole components at the desired height. For the needs of this, a steppermotor system, operating in open loop, was placed on a prototype mechanical tablethat provided motion in three axes using a belt-and-pulley approach for the needs oftesting and evaluation. For additional robustness, a vision system was integrated aswell. By locating the fiducial markers of the board, it is possible to detect offset in Xand Y axes, as well as rotation of the board that was introduced during its placement.The C code that manipulates the motors was combined with the C++ code of thevision system that uses OpenCV in a GUI for increasing the ease of useand user-friendliness in general.The developed system resulted in a positioning accuracy of 0.7 mm, whereas thevision system counteracted the misalignments of sample boards with an accuracy ofup to 0.4 mm. A soldering system operating in tandem with the developed placingsystem has been left as future work, to complete the automated placement ofdiscussed components in desired height, which ultimately eliminates the additionalmanual work during the PCB manufacturing process

This research is part of an effort to develop non-mammalian surrogate immunoessays with the earth worm Lumbricus terrestris to assess immunotoxic potential of xenobiotics to mammals. The objective was to determine if earthworm immunoessays, namely E- and S- rosette formation and phagocytosis, are sensitive to a known mammalian immunotoxin, the PCB Arclor 1254. Results are presented in terms of PCB exposure and tissue concentrations during uptake/depuration.

Polychlorinated biphenyls (PCBs) are the persistent environmental pollutants with the continuous concerns over adverse human health effects. As semi-volatile compounds, PCBs were found in indoor and outdoor air. The observation of high levels of airborne PCBs in old school buildings raised the concerns of inhalation exposure and toxicity of PCBs. Lower chlorinated PCBs (LC-PCBs), major components of airborne PCBs, are subject to biotranformation. In vitro and in vivo studies revealed that reactive metabolites of LC-PCBs formed covalent adducts on DNA and proteins. The hypothesis of the project is that the reactive metabolites of LC-PCBs are able to form adducts on proteins or even protein crosslinks, and the formation of protein adducts and crosslinks causes the dysfunction of the target proteins. In addition, the objectives of the project are also to identify protein targets by PCB metabolites, which may be related to the mechanism of toxicity of LC-PCBs. The alkaline permethylation (AP) was established and optimized to identify and measure the protein adducts from LC-PCB metabolites. The AP method evidenced PCB metabolites formed protein adducts through the sulfhydryl groups and also one molecule of PCB quinoid metabolites was able to bind to more than one protein. Application of cytochrome c as the model protein revealed PCB quinoid metabolites also formed adducts on lysine and glutamic acid. The adduct formation and crosslinks caused the dysfunction of cytochrome c. In addition, the quinone protein adducts still kept the ability for redox reactions, which may lead to unexpected toxicity. The SILAC method was applied to identify the target proteins in the samples of in vitro proteome incubation. The instability of PCB quinone protein adducts was found by further reaction of quinone protein adducts. This may be the reason why cysteine-PCB quinone adducts were not frequently identified by proteomics method. The further understanding of protein adducts by reactive PCB metabolites helps to identify the target proteins, and ultimately reveal the role of protein adducts impacting on human health.

PCBs are known to cause thyroid disruption in laboratory rats and are thought to be the causal agent in thyroid gland alterations in herring gulls in the Great Lakes. This study examined the regulation of thyroid hormone supply during development in (1) domestic chicken embryos (Gallus domesticus) exposed to a specific dioxin-like PCB congener (PCB-126) and (2) herring gull (Larus argentatus) embryos and pre-fledglings from Great Lakes sites with different chemical pollutant exposures. Specifically, PCB effects on thyroid status were evaluated by measuring plasma thyroid hormone concentrations and brain type II 5'D activity (to determine if PCB exposure was associated with alteration in brain 5'D type II activity that could maintain local T3 supply to the brain). If PCB-126 and PCB mixtures altered thyroid function, we expected to see decreased plasma thyroid hormone concentrations and subsequent increases in 5'D-II activity. Chicken eggs were injected (into the air cell) before incubation with five dose levels (0.0512, 0.128, 0.32, 0.64, 0.8 ng/g) of PCB-126 (3,3, 4,4',5-pentachlorobiphenyl), or vehicle (sunflower oil); sampling was on day 20 of the 21-day incubation period. Studies on PCB-treated embryos included a preliminary study and a larger study encompassing a serious of smaller studies. Herring gull embryos (at pipping, on day 25 of the 26 day incubation), and 28-day pre-fledgling chicks were sampled (for two field seasons) at several Great Lakes sites with different contaminant exposures (with Kent Island being the reference site). In PCB-treated chicken embryos, there were no statistically significant decreases in plasma T4 or T3 concentrations and no significant increases in brain 5'D-II activity in either the preliminary or the larger study. We found no clear pattern of altered thyroid function in herring gulls from polluted Great Lakes' sites. Plasma TH concentrations were not significantly decreased and 5'D-II activity did not significantly increase in birds from more contaminated sites in comparison to birds from Kent Island or sites with less contamination. Although pipped embryos from Strachnan Island had a significant increase in 5'D-II activity when compared to Kent Island, there were no differences in plasma TH concentrations, and brain 5'D-II activity was not significantly increased in birds from sites with greater PCB loads than Strachnan Island. Plasma T4 and T3 concentrations were significantly decreased in prefledglings from West Sister Island and Detroit Edison in comparison to Kent Island, but there was no subsequent increase in brain 5'D-II activity. The present study is the first to evaluate the potential effects of PCBs, alone and in a mixed environmental exposure, on circulating THs and brain 5'D-II activity in developing birds. Although thyroid function was not altered by the specific PCB congener used in my study or by exposure to environmental pollutants, more complete evaluations are needed before determining whether PCBs alter thyroid function in birds.
Master of Science

Rapidly growing quantities of e-waste (WEEE) demand the increasing attention of environmental policy all over the world. Developing countries are particularly affected by recycling and disposal activities, which are deemed harmful to health and environment. Holistic or integrated approaches to WEEE policy are required. The paper discusses first recycling technologies for glass from cathode ray tubes (CRT) and printed circuit boards (PCBs) in Vietnam. Thereafter the German approach to WEEE policy is adjusted to allow for an integrated policy. This is then adapted to allow for the recycling of used monitors and computers
Sự gia tăng một cách nhanh chóng số lượng các chất thải từ các thiết bị điện, điện tử (WEEE) đòi hỏi sự tăng cường chú ý tới các chính sách môi trường toàn cầu. Các nước đang phát triển bị tác động đặc biệt bởi các hoạt động tái chế, do nó ảnh hưởng xấu tới sức khỏe và môi trường. Các phương pháp tổ hợp và toàn diện đối với các chính sách quản lý chất thải điện tử (WEEE) là đòi hỏi cấp thiết. Trong bài báo này, trước hết phân tích đánh giá các công nghệ tái chế thủy tinh đèn hình (thủy tinh CRT) và bản mạch in điện tử (PCBs) ở Việt Nam. Tiếp theo là phương pháp tiếp cận các chính sách quản lý chất thải điện tử của Cộng hòa liên bang Đức được sử dụng để điều chỉnh cho thích hợp nhằm đưa ra giải pháp tổ hợp có thể thích ứng cho việc tái chế màn hình Tivi và máy tính hỏng, hết hạn sử dụng và thải bỏ ở Việt Nam

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
As bifenilas policloradas (PCBs) foram durante muitos anos usadas, principalmente, como fluidos refrigerantes e lubrificantes, em transformadores, capacitores e outros equipamentos elétricos. Os éteres difenílicos polibromados (PBDEs) ainda são amplamente utilizados como retardadores de chamas. Ambos são considerados poluentes orgânicos de extrema toxicidade e reportados como potentes interferentes endócrinos. Existem trabalhos anteriores que já detectaram PCBs na baía de Guanabara, porém, a pesquisa sobre PBDEs é pioneira. Foi desenvolvida e validada uma metodologia para extração, simultânea dos PCBs e PBDEs. Todas as amostras foram coletadas, extraídas, limpas e analisadas por GC-MS. Os PCBs foram os poluentes predominantes; entre eles o PCB-153 (bifenila-2, 2’, 4, 4’, 5, 5’-hexaclorada) provou ser o poluente mais disseminado, apresentando teor máximo de 261 ng.g-1 de peso seco no fígado de tainha. A ocorrência dos PBDEs foi significativamente menor; o PBDE-47 (éter difenílico- 2, 2’, 4, 4’-tetrabromado) foi o mais freqüente, apresentando um teor máximo de 46 ng.g-1 de peso seco no músculo de corvina. Comparando-se com outros ecossistemas, as concentrações de PCBs são maiores e as de PBDEs menores.
Polychlorinated biphenyls (PCBs) have been used mainly as coolants and lubricants in transformers, capacitors, and other electrical equipments. Polybrominated diphenyl ethers (PBDEs) are still widely used as additive flame retardants. Both are among the most toxic environmental pollutants and reported as powerful endocrine disruptor. In Guanabara Bay previous studies have already detected PCBs, but the PBDE investigation is pioneer. A procedure for extracting simultaneously PCBs and PBDEs was developed and validated. Samples were collected, extracted, cleaned and analyzed by GC-MS. PCBs were the predominant pollutants, among them PCB-153 (2, 2’, 4, 4’, 5, 5’- hexachlorobiphenyl) proved to be the most disseminated one, with the highest content of 261 ng.g-1 dry weight (dw) in fish liver. PBDE occurrences were significantly lower, being the PBDE-47 (2, 2’, 4, 4’-tetrabromodiphenyl ether the most frequent, with the highest content of 46 ng.g-1 dry weight (dw) in fish tissue. In comparison to other ecosystems PCBs showed higher contents and PBDEs the lower ones.