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.

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.

Polychlorinated biphenyls (PCBs) decrease thyroid function in rats and mice by inducing activity of a liver enzyme, uridine diphosphate-glucuronosyltransferase (UDP-GT), thereby increasing thyroxine (T4) clearance. This loss of T4 can lead to hypothyroidism. In this study, an assay was validated for measuring UDP-GT activity toward T4 in Japanese quail (Coturnix japonica). Then UDP-GT induction by Aroclor 1254 was evaluated in quail, and quail and mice were compared in their responses to Aroclor 1254. In Experiment 1, Japanese quail and Balb/c mice were dosed orally with vehicle or Aroclor 1254 (250 or 500 mg/kg) and sacrificed five days later. In Experiment 2, Japanese quail were dosed orally with vehicle or Aroclor 1254 (500 mg/kg) and sacrificed either five or 21 days later. Total liver UDP-GT capacity increased with Aroclor 1254 exposure in all treatment groups of both species. Enzyme induction led to a trend to decreased plasma T4 concentrations at both doses and exposure times in quail and significantly decreased plasma T4 concentrations at both doses in mice. PCBs altered thyroid function in quail, but they did not become hypothyroid. This was in contrast to mice, which did become hypothyroid. It is unclear how PCBs affect the hypothalamic-pituitary-thyroid (HPT) axis in quail, and activation of the HPT axis appears to be inhibited in mice. Overall, quail showed a lesser response than mice to equivalent doses of Aroclor 1254, so it appears that birds may be less vulnerable to PCBs than mammals. / Master of Science

As bifenilas policloradas (PCBs) são um grupo de compostos hidrocarbonetos halogenados aromáticos, bioacumulativos em organismos vivos e persistente no ambiente. Além da atividade disruptora endócrina, os PCBs podem aumentar os níveis de espécies reativas de oxigênio (ROS), levando ao estresse oxidativo e alteração da metilação de DNA que são fatores importantes nas etiologias da hepatotoxicidade, infertilidade masculina e doença renal. Estes agentes tóxicos podem causar disfunção mitocondrial e distúrbios que afetam a produção de ATP, ROS e morte celular, ocasionando danos à saúde humana. O presente trabalho tem como objetivo investigar possíveis alterações genotóxicas e epigenéticas causadas pelo aroclor 1254 em fígado, rim e testículo, além de verificar a indução de estresse oxidativo e disrupção dos metabólitos intermediários do ciclo de Krebs nos referidos tecidos. Camundongos machos C57/BL6 foram expostos ao Aroclor 1254 em diferentes doses (5, 50, 500 e 1000 ug/kg) por gavagem, uma vez a cada três dias, durante 50 dias. Após a exposição, os animais foram eutanasiados, os órgãos coletados e espermatozoides obtidos a partir dos epidídimos. A peroxidação lipídica em plasma e tecidos foi avaliada pela quantificação de malonaldeído (MDA) por HPLC/DAD. Os níveis de intermediários da via glicolítica, do ciclo de Krebs, de alguns nucleotídeos e aminoácidos, marcas epigenéticas (5-mC e 5-hmC) e adutos de DNA (8-oxodG e CEdG) foram quantificados por HPLC-ESI-MS/MS. A abordagem de benchmark dose (BMD) foi utilizada para a modelagem dose resposta. Após exposição, não foram observadas diferenças significativas da variação da massa corporal, e a razão do peso testicular, fígado e rim por massa corporal. No tecido hepático, foi observado aumento da peroxidação lipídica. Houve redução significativa dos níveis de ATP, ADP, razão NADP+/NADPH, piruvato, malato, fumarato e glutamato. Observou-se redução significativa dos níveis de 5-mC e 5-hmC no DNA nuclear (nDNA), enquanto não foram observadas alterações dos níveis dos adutos. Em DNA mitocondrial (mtDNA) não foram observadas alterações nas marcas epigenéticas, no entanto foi obtido aumento significativo no aduto 8-oxodG após exposição ao Aroclor 1254. No tecido renal foi observado aumento significativo de MDA. Houve aumento significativo dos níveis de lactato e malato e reduções de ATP, ADP, glutamina, NAD+. Foi observada a hipohidroximetilação do mtDNA. As marcas 5-mC de mtDNA, 5mC de nDNA e adutos de DNA nuclear e mitocondrial não apresentaram diferenças após exposição a PCBs. Nos testículos foi verificada redução significativa dos níveis de glutamato, malato, succinato, fumarato e razão NADH/NAD+, hipohidroximetilção em mtDNA e hipermetilação em nDNA. Não foram observadas alterações de 5-mC em mtDNA e 5hmC em nDNA. Não foram verificadas alterações dos níveis de MDA e adutos em nDNA. Adicionando, foi observada redução dos níveis de 5-mC em DNA global de espermatozoide. Os limites inferiores do intervalo de confiança da BMD foram estimados para que estes marcadores possam ser usados na avaliação de riscos de PCBs. Os dados obtidos apontam o Aroclor 1254 como indutor de alterações do metabolismo intermediário, das marcas epigenéticas e estresse oxidativo. Essas alterações podem afetar vias celulares, levando à morte ou transformação, e aumentando o risco de doenças. / Polychlorinated biphenyls (PCBs) are a group of aromatic halogenated hydrocarbon compounds, which bioaccumulate in living organisms and is persistent in the environment. Besides their endocrine disrupting activity, PCBs may increase the levels of reactive oxygen species (ROS), leading to oxidative stress and alter DNA methylation that are important factors in the etiology of liver toxicity, male infertility, and kidney disease. These toxic agents can cause mitochondrial dysfunction and disorders that affect the production of ATP, ROS and cell death, thereby leading to health-related problems. The present work aimed at investigating possible genotoxic and epigenetic changes caused by aroclor 1254 in the liver, kidney and testis, as well as determine the induction of oxidative stress and disruption of intermediate metabolites in these tissues. Male C57/BL6 mice were exposed to Aroclor 1254 at different doses (5, 50, 500 and 1000 µg/kg) by gavage, once every three days, for 50 days. After the exposure period, the animals were euthanized, organs collected, and sperms obtained from the epididymis. Lipid peroxidation in plasma and tissues was determined by quantification of malonaldehyde (MDA) using HPLC/DAD. The levels of intermediate metabolites, epigenetic marks (5-mC and 5-hmC) and DNA adducts (8-oxodG and CEdG) were quantified by HPLC-ESI-MS/MS. The Benchmark dose approach (BMD) was used for dose response modeling. No significant differences in body weight variation, testicular, liver and kidney weight to body weight ratio were observed after exposure. However, in hepatic tissues, an increase in lipid peroxidation was observed. There were significant decreases in the intermediate metabolites including the levels of ATP, ADP, pyruvate, NADP+/NADPH ratio, malate and fumarate, as well as glutamate. Significant reduction of 5-mC and 5-hmC levels in nuclear DNA (nDNA) were observed, whereas no changes were observed in DNA adducts. The epigenetic marks in mitochondrial DNA (mtDNA) were not changed; however, a significant increase was observed in 8-oxodG adduct after exposure to Aroclor 1254. In renal tissues, data showed a significant increase in MDA, while for the intermediate metabolites, the levels of lactate and malate were significantly elevated, whereas significant reductions were recorded for ATP, ADP, glutamine, and NAD+. Hypohydroxymethylation was observed in mtDNA. The 5-mC of mtDNA, 5mC of nDNA and nuclear and mtDNA adducts did not show differences after PCBs exposure. For the testicles, significant reductions in the levels of glutamate, malate, succinate, fumarate and NADH/NAD+ ratio were observed. The PCBs also induced hypohydroxymethylation in mtDNA and hypermethylation in nDNA, but there were no changes of 5-mC in mtDNA and 5-hmC in nDNA. A reduction of nDNA adducts 8-oxodG was observed. No changes were observed in the level of MDA and DNA adducts of nDNA. However, after PCBs exposure there was a significant decrease of 5-mC in global DNA of spermatozoa. The lower bound confidence interval on BMD, which were estimated for these markers can be used in the risk assessment of PCBs. Collectively, the data obtained in this study indicate that Aroclor 1254 induces alteration of intermediate metabolites, epigenetic marks and oxidative stress. These changes can adversely affect cells and cellular pathways, therefore increase the risk of cell death or transformation.

As bifenilas policloradas (PCBs) são um grupo de compostos hidrocarbonetos halogenados aromáticos, bioacumulativos em organismos vivos e persistente no ambiente. Além da atividade disruptora endócrina, os PCBs podem aumentar os níveis de espécies reativas de oxigênio (ROS), levando ao estresse oxidativo e alteração da metilação de DNA que são fatores importantes nas etiologias da hepatotoxicidade, infertilidade masculina e doença renal. Estes agentes tóxicos podem causar disfunção mitocondrial e distúrbios que afetam a produção de ATP, ROS e morte celular, ocasionando danos à saúde humana. O presente trabalho tem como objetivo investigar possíveis alterações genotóxicas e epigenéticas causadas pelo aroclor 1254 em fígado, rim e testículo, além de verificar a indução de estresse oxidativo e disrupção dos metabólitos intermediários do ciclo de Krebs nos referidos tecidos. Camundongos machos C57/BL6 foram expostos ao Aroclor 1254 em diferentes doses (5, 50, 500 e 1000 ug/kg) por gavagem, uma vez a cada três dias, durante 50 dias. Após a exposição, os animais foram eutanasiados, os órgãos coletados e espermatozoides obtidos a partir dos epidídimos. A peroxidação lipídica em plasma e tecidos foi avaliada pela quantificação de malonaldeído (MDA) por HPLC/DAD. Os níveis de intermediários da via glicolítica, do ciclo de Krebs, de alguns nucleotídeos e aminoácidos, marcas epigenéticas (5-mC e 5-hmC) e adutos de DNA (8-oxodG e CEdG) foram quantificados por HPLC-ESI-MS/MS. A abordagem de benchmark dose (BMD) foi utilizada para a modelagem dose resposta. Após exposição, não foram observadas diferenças significativas da variação da massa corporal, e a razão do peso testicular, fígado e rim por massa corporal. No tecido hepático, foi observado aumento da peroxidação lipídica. Houve redução significativa dos níveis de ATP, ADP, razão NADP+/NADPH, piruvato, malato, fumarato e glutamato. Observou-se redução significativa dos níveis de 5-mC e 5-hmC no DNA nuclear (nDNA), enquanto não foram observadas alterações dos níveis dos adutos. Em DNA mitocondrial (mtDNA) não foram observadas alterações nas marcas epigenéticas, no entanto foi obtido aumento significativo no aduto 8-oxodG após exposição ao Aroclor 1254. No tecido renal foi observado aumento significativo de MDA. Houve aumento significativo dos níveis de lactato e malato e reduções de ATP, ADP, glutamina, NAD+. Foi observada a hipohidroximetilação do mtDNA. As marcas 5-mC de mtDNA, 5mC de nDNA e adutos de DNA nuclear e mitocondrial não apresentaram diferenças após exposição a PCBs. Nos testículos foi verificada redução significativa dos níveis de glutamato, malato, succinato, fumarato e razão NADH/NAD+, hipohidroximetilção em mtDNA e hipermetilação em nDNA. Não foram observadas alterações de 5-mC em mtDNA e 5hmC em nDNA. Não foram verificadas alterações dos níveis de MDA e adutos em nDNA. Adicionando, foi observada redução dos níveis de 5-mC em DNA global de espermatozoide. Os limites inferiores do intervalo de confiança da BMD foram estimados para que estes marcadores possam ser usados na avaliação de riscos de PCBs. Os dados obtidos apontam o Aroclor 1254 como indutor de alterações do metabolismo intermediário, das marcas epigenéticas e estresse oxidativo. Essas alterações podem afetar vias celulares, levando à morte ou transformação, e aumentando o risco de doenças. / Polychlorinated biphenyls (PCBs) are a group of aromatic halogenated hydrocarbon compounds, which bioaccumulate in living organisms and is persistent in the environment. Besides their endocrine disrupting activity, PCBs may increase the levels of reactive oxygen species (ROS), leading to oxidative stress and alter DNA methylation that are important factors in the etiology of liver toxicity, male infertility, and kidney disease. These toxic agents can cause mitochondrial dysfunction and disorders that affect the production of ATP, ROS and cell death, thereby leading to health-related problems. The present work aimed at investigating possible genotoxic and epigenetic changes caused by aroclor 1254 in the liver, kidney and testis, as well as determine the induction of oxidative stress and disruption of intermediate metabolites in these tissues. Male C57/BL6 mice were exposed to Aroclor 1254 at different doses (5, 50, 500 and 1000 µg/kg) by gavage, once every three days, for 50 days. After the exposure period, the animals were euthanized, organs collected, and sperms obtained from the epididymis. Lipid peroxidation in plasma and tissues was determined by quantification of malonaldehyde (MDA) using HPLC/DAD. The levels of intermediate metabolites, epigenetic marks (5-mC and 5-hmC) and DNA adducts (8-oxodG and CEdG) were quantified by HPLC-ESI-MS/MS. The Benchmark dose approach (BMD) was used for dose response modeling. No significant differences in body weight variation, testicular, liver and kidney weight to body weight ratio were observed after exposure. However, in hepatic tissues, an increase in lipid peroxidation was observed. There were significant decreases in the intermediate metabolites including the levels of ATP, ADP, pyruvate, NADP+/NADPH ratio, malate and fumarate, as well as glutamate. Significant reduction of 5-mC and 5-hmC levels in nuclear DNA (nDNA) were observed, whereas no changes were observed in DNA adducts. The epigenetic marks in mitochondrial DNA (mtDNA) were not changed; however, a significant increase was observed in 8-oxodG adduct after exposure to Aroclor 1254. In renal tissues, data showed a significant increase in MDA, while for the intermediate metabolites, the levels of lactate and malate were significantly elevated, whereas significant reductions were recorded for ATP, ADP, glutamine, and NAD+. Hypohydroxymethylation was observed in mtDNA. The 5-mC of mtDNA, 5mC of nDNA and nuclear and mtDNA adducts did not show differences after PCBs exposure. For the testicles, significant reductions in the levels of glutamate, malate, succinate, fumarate and NADH/NAD+ ratio were observed. The PCBs also induced hypohydroxymethylation in mtDNA and hypermethylation in nDNA, but there were no changes of 5-mC in mtDNA and 5-hmC in nDNA. A reduction of nDNA adducts 8-oxodG was observed. No changes were observed in the level of MDA and DNA adducts of nDNA. However, after PCBs exposure there was a significant decrease of 5-mC in global DNA of spermatozoa. The lower bound confidence interval on BMD, which were estimated for these markers can be used in the risk assessment of PCBs. Collectively, the data obtained in this study indicate that Aroclor 1254 induces alteration of intermediate metabolites, epigenetic marks and oxidative stress. These changes can adversely affect cells and cellular pathways, therefore increase the risk of cell death or transformation.

Polychlorinated biphenyls (PCBs) are toxic and persistent anthropogenic contaminants. Concern on their adverse health effects has led to their regulation in air, water and/or soil in addition to sludge. Hence, removal of PCBs in various matrices, including transformer oils (TO) is a priority. This study aims to investigate PCB-118 and Aroclor 1254 toxicity and dechlorination by varying certain critical experimental components including electron donor (sludge or fatty acids), inocula (unacclimated or acclimated culture) and the doses of PCB and TO under anaerobic conditions. Anaerobic toxicity assays (ATA) reactors, lab-scale anaerobic batch digesters and sediment microcosms were used for this purpose. Increase in PCB-118 and TO doses affected anaerobic digester performance by negatively influencing methanogenesis, while favoring dechlorination only with the increase in PCB-118 dose. Up to 22% PCB-118 removal was attained with unacclimated culture. Studies with acclimated cultures showed Grasse River (GR) sediment to be the most active when compared to Fox River and Baltimore Harbor sediments. In GR sediment microcosms, PCB-118 and Aroclor 1254 removal efficiencies decreased when TO was present (1%), while 10% TO inhibited PCB dechlorination. Waste activated sludge was shown to be an effective electron donor, similar to fatty acids. Aroclor 1254 dechlorination was dechlorinated through removal of flanked meta and para chlorines, however, dechlorination pathways appeared to differ according to the presence/absence of TO. No ortho or unflanked chlorines were removed. Molecular tools (qPCR and DHPLC) were used to confirm the presence of active PCB dechlorinators. Dechlorination of PCBs was shown to be growth-linked.

PCBs are synthetic organic compounds known for their toxicity to many organisms and are notorious for having large discrepancies between measured and nominal concentrations. Historically thought to be less toxic, non-dioxin-like (NDL) PCBs represent the majority of congeners and are capable of eliciting neurotoxic effects. NDL-PCBs remain understudied, including their effects on aquatic organisms. In the first study, I collected extensive chemistry data and data on neurobehavioral and cardiac endpoints to test the acute effects of exposure to an NDL-PCB mixture on early life stage zebrafish. Neurobehavioral effects observed in the first study indicated a potential for longer term behavioral effects in these fish. In the second study, I collected data on feeding, social, and memory behavior of zebrafish at time points beyond the acute exposure from the first study. Acute and longer-term behavioral endpoints in the first and second studies demonstrated effects from PCB exposure but did not indicate mechanisms. In the third study, I collected untargeted and targeted metabolomic data on amino acid, sugar, anionic compound, and neurotransmitter profiles to determine the specific pathways affected by exposure to an NDL-PCB mixture. These combined data from these studies provide a unique insight into the chemical profile of an NDL-PCB mixture in biological applications and synthesize acute, longer-term, and mechanistic effects on developing zebrafish. These data fully illustrate an adverse outcome pathway from toxicokinetic to population level effects.

The ability of Chromolaena odorata propagated by stem cuttings and grown for six weeks in the greenhouse to thrive in soil containing different concentrations of PCB congeners found in Aroclor and transformer oil, and to possibly remediate such soil was studied under greenhouse conditions. Chromolaena odorata plants were transplanted into soil containing 100, 200, and 500 ppm of Aroclor and transformer oil (T/O) in 1L pots. The experiments were watered daily at 70% moisture field capacity. Parameters such as mature leaves per plant, shoot length, leaf colour as well as the root length at harvest were measured. C. odorata growth was negatively affected by T/O in terms of shoot length and leaf numbers, but no growth inhibition was shown by Aroclor. At the end of six weeks of growth, Plants size was increased by 1.4 and 0.46%, but decreased at -1.0% in T/O, while increases of 45.9, 39.4 and 40.0% were observed in Aroclor treatments. Mean total PCB recoveries were 6.40, 11.7, and 55.8μg in plants tissues at Aroclor treated samples resulting in a percentage reduction of PCB from the soil to 2.10, 1.50, and 1.10 at 100, 200, and 500mg/kg Aroclor treatments respectively. There was no PCB recovery from plants in transformer oil treatments as a result of its inhibition to growth. Root uptake was found to be the probable means of remediation of PCB-contaminated soil by C. odorata, this was perhaps aided by microbes. This study has provided evidence on the ability of C. odorata to remediate PCB contaminated soil. However, the use of C. odorata for phytoremediation of PCB contaminated soil under field condition is therefore advised. / Environmental Sciences / M.Sc. (Environmental Science)

The ability of Chromolaena odorata propagated by stem cuttings and grown for six weeks in the greenhouse to thrive in soil containing different concentrations of PCB congeners found in Aroclor and transformer oil, and to possibly remediate such soil was studied under greenhouse conditions. Chromolaena odorata plants were transplanted into soil containing 100, 200, and 500 ppm of Aroclor and transformer oil (T/O) in 1L pots. The experiments were watered daily at 70% moisture field capacity. Parameters such as mature leaves per plant, shoot length, leaf colour as well as the root length at harvest were measured. C. odorata growth was negatively affected by T/O in terms of shoot length and leaf numbers, but no growth inhibition was shown by Aroclor. At the end of six weeks of growth, Plants size was increased by 1.4 and 0.46%, but decreased at -1.0% in T/O, while increases of 45.9, 39.4 and 40.0% were observed in Aroclor treatments. Mean total PCB recoveries were 6.40, 11.7, and 55.8μg in plants tissues at Aroclor treated samples resulting in a percentage reduction of PCB from the soil to 2.10, 1.50, and 1.10 at 100, 200, and 500mg/kg Aroclor treatments respectively. There was no PCB recovery from plants in transformer oil treatments as a result of its inhibition to growth. Root uptake was found to be the probable means of remediation of PCB-contaminated soil by C. odorata, this was perhaps aided by microbes. This study has provided evidence on the ability of C. odorata to remediate PCB contaminated soil. However, the use of C. odorata for phytoremediation of PCB contaminated soil under field condition is therefore advised. / Environmental Sciences / M.Sc. (Environmental Science)

Métodos de Microbiologia de anaeróbios estritos e de Biologia Molecular foram empregados para se conhecer a diversidade de microrganismos relacionados à degradação de ascarel em reatores anaeróbios metanogênicos. A avaliação de potencial metanogênico foi realizada para a escolha da melhor condição nutricional, bem como, para a seleção de material suporte e solvente adequado a solubilização do ascarel. Nos ensaios em batelada, a produção de metano foi maior nos reatores contendo etanol (média de 0,22 - 0,46 molCH4/gSTV, 46h). Remoção de 85,6% (86,7 mg/L de PCB em Aroclor 1016 e 1260) foi obtida na condição com espuma de poliuretano, etanol (46g/L) e formiato (680 mg/L). Diferentes solventes e surfactantes, tais como, DMSO, dioxano, ácido acético, ácido fórmico, n-hexano, acetona, etano, metanol, Tween 80, SDS (10%) e Triton X-100 foram avaliados para a solubilização de ascarel. Dentre esses, metanol, Triton X-100 e ácido fórmico foram eleitos para a realização de ensaio em reatores em batelada contendo espuma de poliuretano, com o propósito de avaliar o potencial metanogênico na degradação de PCB. Os valores de produção de metano foram muito semelhantes (0,21 0,38 molCH4/mLgSTV, 45h) nas diferentes condições, no entanto, a remoção de PCB foi maior nos reatores com metanol 790 mg/L (86,6%), ácido Fórmico 600 mg/L (84,5%) e Triton X-100 1% (72,1%). Portanto, a melhor condição foi contemplada para a operação do reator anaeróbio horizontal de leito fixo (RAHLF) no tratamento do ascarel, ou seja, células imobilizadas em espuma de poliuretano, etanol e formiato (como fonte de carbono), Triton X-100 (0,1%) e metanol (como solvente). No RAHLF, a remoção média de matéria orgânica (DQO) foi de 91% para concentração afluente média de 1270 mg/L. A presença de morfologias semelhantes à Methanosarcina e bacilos fluorescentes foi confirmada em exames microscópicos. Na análise filogenética, por meio de PCR/DGGE e seqüenciamento das bandas recortadas, os grupos encontrados foram relacionados aos Filos Proteobacteria, Firmicutes, Spirochaetes, Chlorobi e Chloroflexi, sendo que neste último estão incluídos representantes relacionados a degradação de PCBs. Dentre as arquéias metanogênicas verificou-se similaridade de 99% e 97% com Methanosaeta sp. e Methanolinea sp., relacionadas com a metanogenese acetoclástica e hidrogenotrófica, respectivamente / Molecular biology and microbiology methods were used to study the microbial communities related to degradation of ascarel at methanogenic conditions in an anaerobic reactor. The methanogenic potential was evaluated to choose the better nutritional condition as well as to select the better support material and the most suitable solvent to favor the solubilization of ascarel. The methane production was higher (0.22 0.46 molCH4/mLgSTV, 46h) in batch reactors containing ethanol (46 g/L) and formate (680 mg/L), the PCB elimination attaining 85.6% (86.7 mg/L de PCB as Aroclor 1016 and 1260) when Polyuretane foam was used as support material. Different solvents, namely DMSO, dioxane, n-hexane, acetic acid, formic acid, acetone, ethane, methanol, and surfactants, such as 10% SDS,, Triton X-100, were evaluated aiming o determine the better condition to solubilize ascarel. According to the results of such experiments, methanol, formic acid and Triton X-100 were selected for carrying out the batch experiments in reactors containing polyurethane foam to evaluate the methane production during the PCBs degradation. Regardless of the operation conditions the methane production rates were similar (0.21 0.38 molCH4/gSTV, 45h), however the elimination of PCB was higher in the reactors containing methanol (790 mg/L), formic acid (600 mg/L) and Triton X-100 (1%). Therefore, the better condition for treating ascarel-containing residues in a bench-scale horizontal-flow immobilized biomass (HAIB) was attained with cells immobilized in polyurethane foam when ethanol and formate were used as carbon sources, and in presence of Triton X-100 and methanol, the average elimination of organic material attaining 91% for affluent concentration of 1270 mg/L. The presence of Methanosarcina and fluorescent rods was confirmed by microscopy analysis. According to the filogenetics analysis, which was carried out by PCR/DGGE and band-sequencing, the Bacteria domain are related to the Filos Proteobacteria, Firmicutes, Spirochaetes, Chlorobi and Chloroflexi, this latter being directly related to the degradation of PCB. Among the methanogenic Archea, a similiraty of 99% and 97% was observed to Methanosaeta sp. and Methanolinea sp. related to acetoclastic and hydrogenthrophic methanogenesis, respectively