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Dissertations / Theses on the topic 'Environmental toxicology'

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Published: 4 June 2021
Last updated: 30 July 2024

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1

Malheiro, Ana Cristina Calhabeutt Gabriel da Costa. "Determinação espectrofotométrica da caboxiemoglobinemia em indivíduos expostos ocupacionalmente ao monóxido de carbono." Universidade de São Paulo, 1991. http://www.teses.usp.br/teses/disponiveis/9/9137/tde-03032015-160133/.

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O monóxido de carbono (CO) constitui sério risco à saúde de indivíduos expostos a este gás. Os efeitos nocivos aparecem como conseqüência de sua combinação com a hemoglobina formando a carboxiemoglobina(COHb). A avaliação da exposição ao CO pela monitorização biológica é realizada, preferencialmente, pela determinação da carboxiemoglobinemia. O método espectrofotométrico proposto, para a determinação de COHb, utiliza a leitura na região Soret (420 e 432 nm) e fatores de calibração do espectrofotômetro. É realizado estudo comparativo entre o uso do CO obtido por reação química e o de cilindro de gás no preparo de solução 100% de COHb. O método apresenta boa precisão (coeficiente de variação de 2 e 6% para 4,98 e 1,01 % de COHb, respectivamente) e sensibilidade (0,50 % de COHb) adequadas à avaliação da exposição ao monóxido de carbono. A quantificação da COHb não é comprometida pelo teor hemoglobínico nem pela opalescência (lipemia) da amostra colhida no período pós-prandial. É apresentada a carboxiemoglobinemia em fumantes (n= 119) e não-fumantes (n= 189) que constituem 4 grupos de indivíduos expostos ocupacionalmente ao CO (n=209) e um grupo controle (n=99); e a análise estatística dos resultados (teste não-paramétrico).
Carbon monoxide (CO) is recognized as a high risk hazard to the health of exposed workers. Combining with hemoglobin it reduces the oxigen carrying capacity of the blood. The individual overall exposure may be assessed through the carboxyhemoglobin (COHb) content of blood samples, as a biological exposure index. A spectrophotometric method is proposed using measurements in the region Soret (420 - 432 nrn) together with calibration factors of the instrument. A comparative study is made between the use of CO from compressed gas cilinders and the CO delivered by a chemical reaction in preparing the saturated COHb solution. The method presents precision (coefficient of variation is 2 and 6% to 4,98 and 1,01% of COHb, respectively) and sensitivity (0,5% of COHb), which are adequate to the purpose. Hemoglobin and lipidic content of samples showed no effect in the COHb measurement. Carboxyhiemoglobin level of four groups of exposed workers (n = 209) and a control group (n = 99) among smokers (n = 115) and non-smokers (n = 189) were determinated using the method. The statistical analysis of the results are presented (non-parametric test).
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2

Button, Mark. "Arsenic contaminated soils : human exposure and environmental toxicology." Thesis, University of Leicester, 2009. http://hdl.handle.net/2381/7797.

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3

Wilkes, Luanne. "Potential environmental enrichment for zebrafish used in regulatory toxicology." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3456.

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The aim of environmental enrichment is to alter the environment of a captive animal in a way that results in improved mental and physical welfare. The technique has been utilised effectively for many years for captive mammals in a variety of settings. However, until now it has never been considered as a way of improving the welfare of aquatic animals such as fish. Fish that are used in regulatory toxicology studies are at present maintained solely in barren tank environments. Little is known about how these types of environments affect the well-being of the animals residing there and whether they impact either physiological heath or behavioural repertoire. This thesis aims to address this gap in the knowledge regarding the potential for environmental enrichment to improve the welfare of fish used in regulatory toxicology. More specifically it looks at two types of enrichment and the effects of these on the commonly used model species, the zebrafish (Danio rerio). The first type of enrichment studied was glass rod structures of varying heights provided to increase tank complexity and provide refuge. The glass structures did not produce any quantifiable benefits in unstressed fish and appeared to delay the formation of stable social hierarchies. When fish were stressed by a period of chasing, the presence of the glass rods appeared to reduce the magnitude of the cortisol response. Whilst this could be viewed as a potential benefit, it was felt that it would not outweigh the costs of this type of enrichment. The second type of enrichment studied was provision of airstones. Again, no clear evidence was found that fish in tanks with airstones experienced an improvement in welfare. The main observation was the vast increase in mortality in tanks containing these airstones, in particular, those of a smaller size. Regardless of the physiological cause underlying this result, this can only be viewed as a negative consequence and one that appears to rule out airstones as an effective form of enrichment for this species and strain of fish. It was also observed that both stress and the presence of enrichment influenced the absolute deviation from the mean in several endpoints. Since changes in endpoint variation will have effects both on the number of animals required to statistically measure environmentally relevant effects this is a factor that should be considered when researching methods of environmental enrichment. Finally, results from these studies suggest the possibility that laboratory zebrafish do not require the addition of environmental enrichment to tanks in order to promote maximum welfare. Furthermore, as considerable costs would be involved in implementing many types of enrichment (relating to manufacture, cleaning, incompatibility of results with previous studies etc.) it is likely that observed benefits would have to be both substantial and well established in order for changes in regulatory guidelines to take place. For a species such as zebrafish that are extremely easy to breed and maintain in the laboratory with minimal amounts of disease, social problems or mortalities, it may be that current conditions are satisfactory.
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4

Gillespie, Annika Margaret. "Environmental toxicity of complex chemical mixtures." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1017.

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5

O'Rourke, Shona Aisling. "The environmental toxicology of zinc oxide nanoparticles to the oligochaete." Thesis, Heriot-Watt University, 2013. http://hdl.handle.net/10399/2681.

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This thesis investigated the potential toxicity of zinc oxide nanoparticles (NPs) and bulk particles (both with and without organic matter (HA)) to the Californian Blackworm, Lumbriculus variegatus. The NPs and bulk particles in this thesis were characterised using numerous techniques. ZnO NPs were found to be 91 (13364) nm (median (interquartile range)) and ZnO bulk particles were found to be 237 (322165) nm (median (interquartile range)) by TEM. In the acute behavioural study (96 hour), ZnO NPs had a dose-dependent toxic effect on the behaviour of the worms up to 10mg/L whereas the bulk had no significant effect. This result, however, was mitigated by the addition of 5mg/L HA in the NP study whereas a similar addition enhanced the toxicity of the bulk particles at 5mg/L ZnO. In the chronic study (28 days), ZnO NPs and bulk particles were found to have a dose-dependent significant effect on the behaviour of the worms after 28 days, with NPs causing a significantly greater negative response than bulk particles at 12.5, 25 and 50mg/L ZnO. HA had no effect on the toxicity of either particle type in the chronic study. Acute (96 hour) oxidative stress in L. variegatus in response to ZnO NP and bulk particle (with and without 5mg/L HA) exposure was evaluated by examining the changes in glutathione (GSH) content of cells, since NPs are expected to have potential for toxicity via mechanisms such as oxidative stress. Neither ZnO NPs nor bulk particles (with and without 5mg/L HA) were found to induce significant changes in the GSH content of L. variegatus cells after 96 hours of exposure. The uptake, accumulation and depuration of ZnO NPs and bulk particles in L. variegatus over a 48 hour period of uptake and a 48 hour period of depuration were also investigated. This study found a high level of variability and it was concluded that the protocol employed was not suitable for investigating the uptake, bioaccumulation and depuration of ZnO NPs and bulk particles. Finally, histological techniques and a number of fixatives were evaluated for use with L. variegatus. Bouin’s solution was found the most suitable fixative for use with these worms, with no histological damage observed in the morphology of the worms after a 96 hour exposure to ZnO NPs and bulk particles (with and without 5mg/L HA). When considering the toxicology results from all experiments within this thesis it is concluded that ZnO NPs can cause both acute and chronic toxicity in terms of behavioural response, but do not cause acute oxidative stress in L. variegatus.
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6

Boulton, Iain Cameron. "Environmental and experimental toxicology of fluoride in wild small animals." Thesis, University of Sunderland, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306364.

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7

Hillis, James C. McL. "The application of enhanced chemiluminescence in the field of environmental toxicology." Thesis, University of Ulster, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413872.

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8

Naufal, Ziad Sami. "Biomarkers of exposure to complex environmental mixtures." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3284.

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9

Wheeler, Benedict William. "The influence of environmental exposures across the life course on patterns of disease : environmental equity and public health in England and Wales." Thesis, University of Bristol, 2002. http://hdl.handle.net/1983/8c1ba45b-5589-4e2a-9ae6-94274afb7204.

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10

Luizete, Milena Fontes [UNESP]. "Parabenos em água superficial: estudo analítico e aplicação em amostras ambientais." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/97854.

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Produtos de cuidado pessoal são amplamente utilizados pela população. Em sua composição existe uma classe de compostos denominada parabenos que é utilizada pela sua propriedade bactericida e função de conservantes, sendo que tem sido apontados com possíveis alteradores endócrinos para a biota aquática. A literatura internacional relata a presença destes compostos em água naturais, em diversos países, muitas vezes em altas concentrações. No Brasil não há publicações nos quais os parabenos foram determinados em matriz aquosa. Considerando-se que pouca atenção tem sido dada à otimização e validação de método para análise de parabenos em amostras aquosas, neste trabalho desenvolveu-se à validação de método para a análise de parabenos em água de rio, fazendo-se o uso de cartuchos de poliestireno- divinilbenzeno (PSDVB) para extração em fase sólida (SPE) e cromatografia gasosa (CG) acoplada a espectrometria de massas (EM), em tandem, para a quantificação de metil, etil, propil, i-butil, e n-butil parabenos. A recuperação do método foi avaliada em amostras de água obtida no Ribeirão das Cruzes (Araraquara-SP) fortificadas em 3 níveis de concentração: 1; 0,5 e 0,1 ng L-1. A extração dos analitos (500 mL, n=3) resultou em valores de recuperação entre 56 – 100%, e CV menores que 11%. Foi avaliado o efeito de matriz, que indicou ser mandatória a utilização de curvas construídas na matriz para obtenção de dados confiáveis. O método validado foi aplicado com bom desempenho (recuperação do surrogate metilparabeno-d4 superior a 80% com CV <5%) às amostras de água do Ribeirão das Cruzes, a montante a jusante da Estação de Tratamento de Esgoto (ETE) de Araraquara. No ponto a montante todos os parabenos estiveram abaixo dos limites de detecção do método, no entanto para as amostras...
Personal care products are widely used by the population. In its composition there is a class of compounds called parabens which is used for its bactericidal property and function of preservatives, and has been identified with potential endocrine disrupters on aquatic biota. The international literature reports the presence of these natural compounds in water, in many countries, often in high concentrations. In Brazil there are no publications in which the parabens were determined in aqueous matrix. Considering that little attention has been paid to the optimization and validation of method for analysis of parabens in aqueous samples in this study was developed to validate the method for the analysis of parabens in river water, making the use of cartridges polystyrene-divinylbenzene (PSDVB) for solid phase extraction (SPE) and gas chromatography (GC) coupled with mass spectrometry (MS), tandem for the quantification of methyl, ethyl, propyl, i-butyl, and n-butyl parabens. The recovery of the method was evaluated in water samples obtained in Ribeirão das Cruzes (Araraquara-SP) fortified at 3 levels of concentrations: 1, 0.5 and 0.1 ng L-1. The extraction of analytes (500 mL, n = 3) resulted in recovery values between 56-100% and CV less than 11%. The effect of matrix, which indicated that it was mandatory to the use curves built into the array to obtain reliable data. The validated method was applied with good performance (recovery of surrogate methyl-d4 than 80% with CV <5%) to water samples from Ribeirão das Cruzes, upstream to downstream of Sewage Treatment Plant (WWTP) in Araraquara. At any point upstream parabens were below the detection limits method, however to samples collected downstream of the STP only the methyl and ethyl paraben were identified, only possible to quantify the methylparaben... (Complete abstract click electronic access below)
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11

Mello, Fernando Aquinoga de 1982. "Critérios ecotoxicológicos de lançamento de efluentes : aspectos teóricos e práticos." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267718.

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Orientador: Gisela de Aragão Umbuzeiro
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia
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Resumo: O controle do lançamento de efluentes ocorre tradicionalmente por meio de caracterização fisico-química e comparação com padrões estabelecidos por substâncias químicas, no entanto, é sabido que o atendimento a estes valores não assegura que efeitos adversos aos organismos aquáticos não ocorram. Por isso, as avaliações ecotoxicológicas do próprio efluente, utilizando diferentes abordagens, passaram a ser utilizadas em vários países inclusive o Brasil. O objetivo deste trabalho foi realizar uma avaliação crítica dos critérios ecotoxicológicos de lançamentos de efluentes praticados no Brasil por meio da análise dos instrumentos legais vigentes no âmbito dos estados (RS, SC, PR, SP e RJ), bem como da regulamentação federal. Observou-se que os critérios em uso no Brasil são fundamentados tanto no conceito de melhor tecnologia de tratamento disponível como na proteção da comunidade aquática do corpo receptor. Os padrões originados da abordagem aplicada na Alemanha, baseada na redução das cargas tóxicas, são utilizados pelos estados de Santa Catarina, Paraná, Rio de Janeiro e Rio Grande do Sul, sendo que este último adotou como meta a ausência da toxicidade no efluente. Já os padrões originados a partir da experiência norte-americana focam na concentração aceitável da mistura para o corpo receptor. O estado de São Paulo utiliza fatores de segurança para garantir a ausência de efeitos tóxicos crônicos, a representatividade de vários níveis tróficos e as variações da ecotoxicidade; já os estados de Santa Catarina e Paraná adotaram critérios arbitrários que ao final, se traduzem em diferenças da ordem de 100 vezes na tolerância de efeitos entre as regulamentações. Tal situação, além de gerar diferentes exigências tecnológicas para o mesmo segmento, pode implicar em diferentes níveis de proteção a comunidade aquática, o que pôde ser observado com a aplicação dos padrões ecotoxicológicos em casos concretos
Abstract: Traditionally the control of effluent discharge occurs through physical-chemical characterization and comparison with standards fixed by chemicals, however, it¿s known that the compliance with these values doesn¿t ensure that adverse effects do not occur. Therefore, the ecotoxicological assessments of own effluent, using different approaches, have been used in several countries including Brazil. This study aimed make a critical assessment of ecological criteria for effluent discharges practiced in Brazil through the analysis of existing legal instruments at states (RS, SC, PR, SP and RJ) as well as the federal regulation. It was observed that the use of criteria in Brazil is based on both concept of best technology of treatment available as the protection of aquatic community at receiving body. The standards originated the approach applied in Germany, based on the reduction of toxic loads, are used by states of Santa Catarina, Paraná, Rio de Janeiro and Rio Grande do Sul, the latter adopted as a goal the absence of toxicity in the effluent. In the other hand, the standards originated from the US experience focus on acceptable concentration of the mixture to the receiving body. The state of São Paulo uses safety factors to ensure the absence of chronic toxic effects, the representation of several trophic level and the variations ecotoxicity; the states of Santa Catarina and Paraná adopted arbitrary criteria that ultimately translate into differences in the order of 100 times in the tolerance effects between the regulations. This situation, in addition to generating different technological requirements for the same segment, could result in different levels of aquatic community, which could be observed with the application of ecotoxicological standards in specific cases
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Tecnologia e Inovação
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12

Arine, Ana Lúcia Fermino de Oliveira. "Estudo da viabilidade de sedimentos formulados para a aplicação em estudos ecotoxicológicos e químicos: ênfase para os interferentes endócrinos 17alfa-etinilestradiol e 17beta-estradiol /." Sorocaba, 2015. http://hdl.handle.net/11449/122163.

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Orientador: Renata Fracácio
Banca: Leonardo Fernandes Fraceto
Banca: Cleoni dos Santos Carvalho
Resumo: O uso de sedimentos formulados em laboratório vem sendo largamente adotado e recomendado por organizações de proteção ambiental e outras entidades internacionais de importância, como U.S.EPA, OECD e ASTM, devido, principalmente, à sua fácil reprodutibilidade por diferentes laboratórios e por ser livre de organismos e contaminantes indesejados no estudo. Visando a representatividade de ambientes lóticos tropicais, este estudo propôs analisar diferentes formulações de sedimento para a aplicação em estudo toxicológico de interferentes endócrinos (IE), sendo eles o 17β-estradiol (E2) e 17α-etinilestradiol (EE2). Foram avaliados os parâmetros oxigênio dissolvido, dureza e pH de 5 formulações de sedimento durante um período de 15 dias e a adaptação da espécie bentônica Hyalella azteca com relação aos parâmetros sobrevivência, crescimento e reprodução. A toxicidade do E2 e EE2, ambos à concentração de 30 ng/L, foi verificada sobre o organismo nectônico Ceriodaphnia dubia, exposto por 8 dias em solução extraída da formulação de sedimento que continha menor quantidade de matéria orgânica, contaminada em laboratório. Os parâmetros avaliados foram sobrevivência e reprodução, sendo utilizados os métodos estatísticos de Kruskal- Wallis, teste t e teste t por bioequivalência. O comportamento químico dos compostos foi analisado quanto ao tempo de degradação em ambiente com sedimento formulado (após 2, 24 e 48 horas de contato) e à capacidade de retenção ao sedimento após 2 horas de contato através de quantificação por cromatografia gasosa acoplada a espectrometria de massa (GC-MS). Os resultados mostraram que os sedimentos formulados contendo menores proporções de matéria orgânica (1 e 3% em massa) tiveram melhor estabilização em relação ao pH e também boa aceitação pela espécie H. azteca. Porém, o ambiente composto pelo mesmo sedimento não foi ideal para testes com C. dubia...
Abstract: The use of laboratory-formulated sediments have been widely adopted, and recommended by environmental protection organizations and other international agencies as USEPA, OECD, and ASTM, mainly for easy reproducibility by different laboratories, and for being free of unwanted contaminants and indigenous organisms. Aiming at the representation of tropical lotic environments, different sediment formulations were analyzed for use in toxicology studies of endocrine disruptors (EI), namely 17β-estradiol (E2) and 17α-ethinyl estradiol (EE2). Five different formulations were evaluated regarding dissolved oxygen, water hardness and pH over a period of 15 days, and on the adaptation of the benthic species Hyalella azteca regarding survival, growth, and reproduction parameters. The toxicity of E2 and EE2, both at the concentration of 30 ng/L, was observed in the nektonic organism Ceriodaphnia dubia, exposed to a solution extracted from spiked formulated sediment containing a minor amount of organic matter in a 8-days test. Survivability and reproduction parameters were evaluated using Kruskal-Wallis, t-test and bioequivalence t-test statistical methods. Chemical behavior of the compounds was analyzed regarding environmental degradation time in formulated sediment (after 2, 24, and 48 hours of contact), and sediment retention capacity after 2 hours of contact by quantification by gas chromatography-mass spectrometry (GC-MS). Results showed that the formulated sediments which contained smaller fractions of organic matter (1% and 3% dry weight) had better stabilization in relation to pH, and good acceptance by the species H. azteca. However, the formulated sediment environment was not ideal for C. dubia, which was therefore replaced by filtered interstitial water for E2 and EE2 tests. There was a statistically significant reduction in the number of newborns when exposed to control sediment and contaminants (Kruskal-Wallis, t-test, and bioequivalence ...
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Watanabe, Cláudia Hitomi. "Avaliação ecotoxicológica de metais/metalóides e interferentes endócrinos em frações de substâncias húmicas de diferentes tamanhos moleculares /." Sorocaba, 2015. http://hdl.handle.net/11449/124025.

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Orientador: André Henrique Rosa
Coorientador: Renata Fracácio
Banca: Alessandra Emanuele Tonietto
Banca: Viviane Moschini Carlos
Resumo: No presente trabalho, ensaios de toxicidade com o metalóide arsênio, o metal cobalto e o contaminante emergente17β-estradiol foram estudados na presença e ausência das substâncias húmicas aquáticas (SHA) e suas frações de diferentes tamanhos moleculares (<5, 5-10; 10-30; 30-100 e >100 kDa), utilizando-se os organismos Ceriodaphnia dubia e Pseudokirchneriella subcapitata. Aos ensaios utilizando-se o organismo C. dubia, a influência das SHA em contato com o metal arsênio na redução da toxicidade por análise estatística aumentou a reprodução. Nas diferentes frações de SHA observou-se variação de toxicidade nas frações de tamanhos moleculares maiores, na seguinte ordem crescente de toxicidade: F1=F2Abstract: At this work, toxicity tests using metalloid arsenic, metal cobalt and emerging contaminant 17β-estradiol were studied in the presence and absence of aquatic humic substances (AHS) and its fractions of different molecular sizes (<5, 5-10; 10-30; 30-100 and > 100 kDa), using the Ceriodaphnia dubia and Pseudokirchneriella subcapitata organisms. The tests using C. dubia, influence of AHS contact arsenic metal in toxicity reducing by statistical analysis AHS and the different fractions showed different behavior in each other, reducing toxicity fractions of larger molecular size, in decreasing order of toxicity: F1 = F2 Mestre
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14

Luizete, Milena Fontes. "Parabenos em água superficial : estudo analítico e aplicação em amostras ambientais /." Araraquara, 2013. http://hdl.handle.net/11449/97854.

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Orientador: Wagner Vilegas
Coorientador: Mary Rosa Rodrigues de Marchi
Banca: Eny Maria Vieira
Banca: Mario Sérgio Galhiane
Resumo: Produtos de cuidado pessoal são amplamente utilizados pela população. Em sua composição existe uma classe de compostos denominada parabenos que é utilizada pela sua propriedade bactericida e função de conservantes, sendo que tem sido apontados com possíveis alteradores endócrinos para a biota aquática. A literatura internacional relata a presença destes compostos em água naturais, em diversos países, muitas vezes em altas concentrações. No Brasil não há publicações nos quais os parabenos foram determinados em matriz aquosa. Considerando-se que pouca atenção tem sido dada à otimização e validação de método para análise de parabenos em amostras aquosas, neste trabalho desenvolveu-se à validação de método para a análise de parabenos em água de rio, fazendo-se o uso de cartuchos de poliestireno- divinilbenzeno (PSDVB) para extração em fase sólida (SPE) e cromatografia gasosa (CG) acoplada a espectrometria de massas (EM), em tandem, para a quantificação de metil, etil, propil, i-butil, e n-butil parabenos. A recuperação do método foi avaliada em amostras de água obtida no Ribeirão das Cruzes (Araraquara-SP) fortificadas em 3 níveis de concentração: 1; 0,5 e 0,1 ng L-1. A extração dos analitos (500 mL, n=3) resultou em valores de recuperação entre 56 - 100%, e CV menores que 11%. Foi avaliado o efeito de matriz, que indicou ser mandatória a utilização de curvas construídas na matriz para obtenção de dados confiáveis. O método validado foi aplicado com bom desempenho (recuperação do surrogate metilparabeno-d4 superior a 80% com CV <5%) às amostras de água do Ribeirão das Cruzes, a montante a jusante da Estação de Tratamento de Esgoto (ETE) de Araraquara. No ponto a montante todos os parabenos estiveram abaixo dos limites de detecção do método, no entanto para as amostras... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Personal care products are widely used by the population. In its composition there is a class of compounds called parabens which is used for its bactericidal property and function of preservatives, and has been identified with potential endocrine disrupters on aquatic biota. The international literature reports the presence of these natural compounds in water, in many countries, often in high concentrations. In Brazil there are no publications in which the parabens were determined in aqueous matrix. Considering that little attention has been paid to the optimization and validation of method for analysis of parabens in aqueous samples in this study was developed to validate the method for the analysis of parabens in river water, making the use of cartridges polystyrene-divinylbenzene (PSDVB) for solid phase extraction (SPE) and gas chromatography (GC) coupled with mass spectrometry (MS), tandem for the quantification of methyl, ethyl, propyl, i-butyl, and n-butyl parabens. The recovery of the method was evaluated in water samples obtained in Ribeirão das Cruzes (Araraquara-SP) fortified at 3 levels of concentrations: 1, 0.5 and 0.1 ng L-1. The extraction of analytes (500 mL, n = 3) resulted in recovery values between 56-100% and CV less than 11%. The effect of matrix, which indicated that it was mandatory to the use curves built into the array to obtain reliable data. The validated method was applied with good performance (recovery of surrogate methyl-d4 than 80% with CV <5%) to water samples from Ribeirão das Cruzes, upstream to downstream of Sewage Treatment Plant (WWTP) in Araraquara. At any point upstream parabens were below the detection limits method, however to samples collected downstream of the STP only the methyl and ethyl paraben were identified, only possible to quantify the methylparaben... (Complete abstract click electronic access below)
Mestre
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15

Sved, Daniel W. "Monooxygenase induction and lethality as endpoints in aquatic toxicology." W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539616869.

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Spot, Leiostomus xanthurus, were exposed to suspended sediments (&\approx&20 mg/L) contaminated with polycyclic aromatic hydrocarbons (PAH) in a laboratory flow-through system to evaluate the applicability of hepatic ethoxyresorufin O-deethylase (EROD) induction as an indicator of PAH exposure. PAH sources tested were coal-tar creosote (CTC), a low molecular weight fraction of creosote (LMWF), and a high molecular weight fraction of creosote (HMWF). A standard 96-h acute toxicity test was conducted to ensure that PAH concentrations tested in induction studies were sub-acutely toxic. The 96-h LC50 for spot was 1740 &\mu&g PAH/L (95% confidence interval = 1480-2060 &\mu&g PAH/L). The lowest concentration producing an observable effect in 96 h was 560 &\mu&g PAH/L; no effects were observed for spot exposed to 250 &\mu&g PAH/L for 96 h. Induction of hepatic EROD activity occurred rapidly in fish exposed to high environmentally realistic concentrations of CTC or the HMWF, but not the LMWF. Maximal induction (30-fold) occurred in fish exposed for 48 h to 150 &\mu&g PAH/L. Induction was concentration-dependent up to 150 &\mu&g PAH/L; at 320 &\mu&g PAH/L induction was 14-fold. EROD activity decreased upon further exposure; by day 7, EROD activity was not significantly different than that on day 0. EROD activity in fish exposed to 16 &\mu&g PAH/L was not consistently higher than that in control fish. Spot exposed to at least 70 &\mu&g PAH/L from CTC or the HMWF experienced severe fin erosion, epidermal lesions, and mortality beginning a few days after maximal EROD induction occurred. No relationship between EROD induction and whole animal responses is implied, only that EROD induction did precede any high order effects. These results indicate complications to the use of EROD activity as a sensitive, reliable indicator of PAH exposure. The toxicity of CTC may inhibit or interfere with continued induction of EROD activity, but neither the toxicity nor inducing capability is associated with the LMWF. The lack of exposure-dependent EROD induction indicate there could be difficulties in interpreting field studies, where fish have unknown exposure histories.
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16

Shelton, Delia S. "Environmental features influence complex behavior in small groups of animals." Thesis, Indiana University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10161866.

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Simple environmental features can shape complex behavior. Identifying key aspects of the environment (e.g., temperature, structure, toxins) that lead to widespread consequences is of central importance in a changing world. The primary objective of my dissertation is to investigate how relatively simple aspects of the environment can influence small groups of animals in profound and complex ways. In the first three chapters, I report on experiments showing how small changes in the environment can affect the expression of behavior at different points in development and can have important physiological consequences for litters of mouse pups. I then report on two sets of experiments showing how subtle changes in the environment can dramatically affect spacing patterns and social dynamics of small groups of adult zebrafish. Together, my results emphasize the ways that subtle changes in the environment can have profound impacts on individuals and small groups. In both lines of work, I have found that a more accurate characterization of the phenomena, infant rodent development and zebrafish social behavior, requires the use of individual and group measures and that temperature, density, and pollutants can have a powerful effect on group responses. These results are important because they show that the physical environment can have profound effects on the phenotype, and that with a changing physical environment or anthropogenic change, dramatic differences may be observed in the behavior of groups.

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17

Méndez, Sara I. Semlitsch Raymond D. "Aquatic and terrestrial exposure of amphibians to estrogenic endocrine disrupting contaminants." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6183.

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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 15, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Raymond D. Semlitsch Vita. Includes bibliographical references.
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18

Lai, Keng Po. "Study on the environmental contamination and mechanistic toxicology of 2,3,7,8-tetrachlorodibenzo-p-dioxin." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/527.

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19

Briscoe, Scott F. "Tributyltin : molecular approaches to an environmental problem." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85133.

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Tributyltin compounds have been used on a global scale for many decades now, and thus have become global environmental contaminants. These compounds are highly toxic, and deleterious effects on numerous organisms have been demonstrated. Yet, little is known of the molecular mechanisms of tributyltin's extreme toxicity. To obtain a better understanding of such mechanisms, a luxAB gene-fusion library of Escherichia coli was screened for changes in gene expression upon cellular exposure to tributyltin. Two clones, designated TBT1 and TBT3, were thus found, both showing an increased light emission in the presence of added tributyltin. Northern blotting analyses confirmed a marked increase in the transcription of the tributyltin-responsive gene identified from each clone. These genes appear to play a protective role when cells are exposed to tributyltin at concentrations ≧ 10 mug/ml, with minimal-dose responses of 0.1 mug/l when grown on LB media. Speciation studies indicated TBT+ as the active chemical species in eliciting these responses. Mapping and sequencing of these tributyltin-responsive genes revealed that the luxAB reporter element had inserted within the uhpT gene in the TBT1 clone. This gene encodes a sugar-phosphate transporter protein, which has been shown to be up-regulated by external glucose-6-phosphate and 2-deoxyglucose-6-phosphate. On a kinetic level, the increased expression of uhpT by tributyltin closely mirrors that produced by 2-deoxyglucose-6-phosphate. In addition to tributyltin, TBT1 also responds to dibutyltin, monobutyltin, trimethyltin, triethyltin, tripropyltin, trifluoroacetic acid, and vanadium. Similar mapping and sequencing experiments revealed the luxAB reporter genes within the stpA gene in the TBT3 clone, but in an antisense orientation, such that they were not under the regulatory control of stpA. The lack of an appropriate open reading frame for this 140-nucleotide transcript (identified by Northern blo
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20

Saunes, Halvor. "Do mercury, selenium, cadmium and zinc cause oxidative stress in common eiders (Somateria mollissima) from Svalbard?" Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12755.

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The levels of mercury have shown to increase in the Arctic environment as a cause of human activities. Few studies have examined the antioxidant system as a response to heavy metals in Arctic seabirds. Levels of the elements mercury (Hg), selenium (Se), cadmium (Cd) and zinc (Zn) were analyzed in hepatic tissues of female common eiders (Somateria mollissima) collected in July 2008 and 2009 from Kongsfjorden (KF) and Liefdefjorden (LF), Svalbard. The molar ratio of Hg relative to Se (ratio Hg:Se) was also calculated. The two fjord systems are dominated by inflow of different water masses (Atlantic vs. Arctic), which are suggested to vary in the abundance of contaminants. As an indicator of heavy metal exposure, antioxidants in the defense against reactive oxygen species (ROS) were analyzed. These were total reduced glutathione (tGSH), oxidized glutathione (GSSG) and their ratio (tGSH:GSSG), together with its unique enzymes glutathione reductase (GR) and glutathione peroxidase (GPx). Other proteins quantified included metallothionein (MT) and catalase (CAT). As a measure of oxidative damage the levels of lipid peroxidation (TBARS) were analyzed. Se, ratio Hg:Se, GSSG, ratio tGSH:GSSG, GPx and CAT were found to be significantly different between the locations; however this was only in 2008. No parameter was found significantly different between the fjords in 2009. Differences were mainly thought to be caused by seasonal changes between the locations and years rather than various inflows of Atlantic and Arctic waters in the two fjords. The common eiders seems to be less affected by the examined elements compared to seabirds at higher trophic position, except with respect to Se, which were found in relative high concentrations. In the general linear models (GLM) Hg was a strong predictor of levels of GR and MT. In addition, Se was found to correlate with GPx and Zn correlated strongly with MT. However, the metals revealed fewer relationships with enzyme activity compared to previous studies. The present study suggests that several physiological and ecological factors are more important than element burden in explaining differences in status of the antioxidant defense system. This especially involves the female common eider which goes through a prolonged period of incubation fast.
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21

Mulder, Paulien Jakobje. "Thyroid hormone disruptive effects of environmental contaminants in free-ranging brown trout (Salmo trutta) from lake Mjøsa, Norway." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12758.

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VBrown trout (Salmo trutta) from Lake Mjøsa, Norway, contain very high levels of polybrominated diphenyl ethers (PBDEs), in addition to elevated levels of other persistent organic pollutants (POPs) and trace metals, including mercury (Hg). By contrast, the levels of Se in brown trout are low. This study investigated whether the plasma thyroid hormone (TH) levels of free-ranging trout in Lake Mjøsa were affected by the various contaminants and oxidative stress. Both plasma thyroxine (T4) and triiodothyronine (T3) levels were affected by the contaminants investigated. Selenium variables in muscle were positively correlated with both TT3 and the total to free T3 (TT3:FT3) ratio, where the Se:Hg molar ratio was the best predictor of TT3, and Se was the best predictor of TT3:FT3. The Se:Hg ratio in muscle tissue also was an important predictor of total T4, and a weaker predictor of FT4 levels in the trout. Furthermore, Hg alone also correlated negatively with several T4 variables. It is suggested that Se acts as an antagonist against Hg induced TH disruptive effects, and that trout from Lake Mjøsa may be susceptible to effects due to low Se levels in the lake. Hepatic concentration of several heavy metals, especially cadmium and chromium, were also negatively related to T3 levels. Plasma THs were not well correlated with the POPs, but weak negative effects on TT4 and total to free T4 (TT4:FT4) were observed for several PBDEs and polychlorinated biphenyls (PCBs). Biomarkers of increased hepatic oxidative stress (the glutathione system) were not linked to depleted TH levels, but associated with bioavailability of Se, which likely accounted for the positive correlation between oxidized glutathione and T3 in the trout. Since relationships between THs and trace elements were stronger than relationships between THs and POPs, it is suggested that measurements of both POPs and trace elements should be included in studies that aim to investigate TH disruptive effects in free-ranging freshwater fish.
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22

Gjøsund, Nina Szaniawska. ""Bottom up" ocean acidification: A study on the effects of CO2 on the bacterial community in sediments." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12759.

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23

Nilsen, Else Mari Espseth. "Temporal Change and Effects of Perfluoroalkyl Substanses (PFASs) on Thyroid Hormone Levels in Mother-Cub Pairs of Polar Bear (Ursus maritimus) from Svalbard in 1998 and 2008." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12761.

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High levels of persistent organic pollutants (POPs) have been detected in the Arctic wildlife. While many of the traditional POPs have been reported to decline the last decades, emerging contaminants such as perfluoroalkyl substanses (PFASs) have been detected in increasing amounts in biota worldwide. PFOS has been the major PFASs detected and the leading manufacturer of PFOS announced a voluntarily phase-out of the perfluorooctanesulfonyl fluoride (POSF) chemistry and ended the production in 2002. However, other PFASs are still being used in the industry and no regulations have been established. The toxicological effects of PFASs are not fully elucidated, but they have been linked to hepatotoxicity, developmental toxicity, immunotoxicity and disruption of hormone homeostasis.The aim of this study was to investigate temporal changes of PFASs and to evaluate possible relationships between PFASs and circulating thyroid hormone (TH) levels in polar bear (Ursus maritimus) mother-cub pairs from Svalbard sampled in 1998 (12 mother-cub pairs) and 2008 (9 mother-cub pairs). Plasma samples from all polar bears were extracted by liquid-liquid extraction (LLE) using methanol and analysed for perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTrDA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS) and perfluorooctane sulfonamide (PFOSA) using liquid chromatography – mass spectrometry (LC-MS). Total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3) and free triiodothyronine (FT3) were quantified by the use of radioimmunoassay (RIA). Relationships between PFASs, THs, age (only mothers), capture day and biometric variables were investigated by the use of principle component analysis (PCA) and general linear models (GLM).PFHpA, PFOA and PFOS showed significant decreasing levels in mothers, while the levels did not differ between the years in cubs. In contrast, the longest chain perfluorinated carboxylic acids (PFCAs) showed significantly increasing concentrations over time in both mothers (PFNA, PFUnDA, PFDoDA, PFTrDA) and cubs (PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, PFTeDA). Concentration of PFBA, PFPeA and PFHxA were not detected in mothers or cubs, PFBS was detected in one mother and PFOSA was only detected sporadically. A positive relationship was observed between the longest chain PFCAs and TT3 in both mothers and their offspring, particularly with regard to PFTrDA in mothers and PFDoDA in cubs. In addition, TT3 and body mass were positively correlated in cubs. In contrast to the longest chain PFCAs, no relationships were observed between PFOS and THs in the polar bear plasma samples. The positive correlation between TT3 and the longest chain PFCAs may indicate a possible interaction between PFCAs and the TH homeostasis in polar bear mother-cub pairs. However, no final conclusions can be drawn based on the mechanism behind this finding and further research is needed on these emerging contaminants to elucidate their potential TH-disrupting effects.
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24

Thorsen, Marte Høye. "Mutagenicity and induction of CYP1A- enzymes from organic extracts of soil samples from nursery schools, evaluated by in vitro studies." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12763.

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Polluted soil can be a problem in urban areas, and can have a direct impact on human health upon exposure. The toxic potential of mixtures can be mediated by constituents and information about toxicity of mixtures is regarded as important, as it represents the real exposure situation. The main purpose of this project was to measure the mutagenic and CYP1A inducing potential in vitro from organic extracts of soil, sampled in nursery schools in Oslo. Selection of soil was mainly based on the content of ∑PAH16 and ∑PCB7, chemical groups known to include CYP1A inducing and/or genotoxic and mutagenic compounds. Generally were Soil 1 considered as a “clean” sample, Soil 2 to Soil 4 contained increasing level of PAHs and Soil 5 contained mainly elevated levels of PCBs. Assessing varying samples in relation to chemical content was valuable due to potential differences in biological responses. The soil samples were of top soil (0- 2 cm depth) and had been collected by NGU in connection to a geological survey of soil at playgrounds in nursery schools and schools in Norway. The soil was sampled in 2005- 2007, dried at 40 °C for one to two weeks, sieved in a 2 mm nylon sieve and stored in the dark at room temperature. Chemical analyses of both inorganic and organic compounds were performed before storage. In relation to this master project the organic pollutants in the selected soil samples were extracted by ultrasonic agitation in dichloromethane (DCM). Before experimental use the solvent was changed into dichloromethane (DMSO) by evaporating off the DCM using a water bath at 25 °C and a flow of nitrogen above. The dried extracts were redissolved in DMSO.The Ames Salmonella typhimurium assay was used for measuring mutagenicity. The presence of primary and secondary mutagens was assessed by conducting the assay both with and without addition of a metabolic S9- mix. Induction of different point mutations was revealed by utilising two bacterial strains, TA98 and TA100, detecting frameshift and base- pair substitutions, respectively. Induction of CYP1A enzymes was assessed in the rat H4IIE hepatoma cell line, and measured immunologically by Western blotting. The exposure concentrations used in the CYP1A assay were based on results of cell viability, assessed by utilising MTT- assay for finding the highest non- cytotoxic exposure concentrations. Concentration ranges of the extracts were tested in both assays. The mutagenic potential of extracts showed presence of secondary mutagenic compounds, and indicated absence or very low levels of primary mutagens. It was a general incidence of higher mutagenic activity with TA98 than TA100, reflecting highest induction of frameshift mutations. The inducing potential of extracts was in accordance with chemical analysis, showing a general increase in the potential of extract from Soil 1 to Soil 4, suggested to partly reflect differences in level of PAHs. The relative low potency of extract from Soil 5 was considered to be a reflection of a low content of PAHs and an expected dominance of PCBs, which have shown not to induce mutagens in the Ames assay.Induction of CYP1A in H4IIE was measured after exposure to extracts of Soil 3, Soil 4 and Soil 5. Results clearly indicated presence of CYP1A inducers in the extracts. A positive concentration- effect relationship was detected from exposure to extract of Soil 5. Extract of Soil 3 and Soil 4 did clearly induce CYP1A, but in a negative concentration dependent manner. These negative responses were suggested to indicate inhibition of CYP1A induction at the higher concentration, which may be linked to antagonism at the Ah- receptor. The biological endpoints measured in the current project reflected the integrated effect from extract exposure, potentially affected by additivity, synergism and/or antagonism. Differences in toxicity between in vitro and in vivo conditions, along with several biological and environmental parameters can affect the biological responses. The results obtained in the current project indicated presence of potential hazards in the soil, but no further conclusion could be drawn about the actual hazard from humans exposure to polluted soil.
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25

Rørvik, Siv Fiske. "Acute Toxicity and Stress Gene Transcription in Two Copepod Species (Calanus finmarchicus and Calanus glacialis) Exposed to Fresh Crude Oil WSF." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13265.

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Increasing oil activities from the gas and oil industry may constitute a hazard towards the marine environment due to potential risks for accidents, such as oil spills. This study examine acute eects on mortality (LC50) and stress gene expressions in two closely related copepod species, Calanus finmarchicus(temperate-boreal species) and Calanus glacialis (Arctic species), adapted to dierent temperatures 10 C and 2 C, respectively. The copepod species were exposed to water soluble hydrocarbon fractions (WSFs)of fresh crude oil. In addition, an experiment was conducted in order to investigate if lipid rich specimen survived a longer exposure of WSFs than lipid poor specimen. The results from the acute toxicity tests indicated that the Arctic species is more tolerated to WSF exposure than the temperate species. Gene expression analysis revealed that both species induced glutathione S-transferase (GST) mRNA levels in a concentration- and time related manner. Calanus glacialis showed a greater and faster induction of the GST transcription compared to Calanus nmarchicus. The results of gene expression analysis of superoxide dismutase (SOD), cytochrome 330A1 (CYP330A1) and gamma-glutmylcystein synthase (gGCS) did not show any concentration- and time related trends following WSF exposure. Biometric measurements of the specimen, and analyzing by a linear multi variable regression model showed that neither of the variables, including the lipid content, explained the dierences in surviving a WSFs exposure. The study support the use of the cultured Calanus species as a model species when testing for acute eects in themarine environment.
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26

Leeves, Sara Ann. "Bioaccumulation of arsenic, cadmium, mercury, lead and selenium in the benthic and pelagic food chain of Lake Baikal." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13438.

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Increased anthropogenic release of potentially toxic trace elements such as arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and selenium (Se) into freshwater ecosystems over the past century has caused much concern. These elements are well known toxicants in aquatic ecosystems and may exert toxic effects even if present at relatively low concentrations in organisms. In this study, bioaccumulation of As, Cd, Hg, Pb and Se in the pelagic and benthic food chain of Lake Baikal have been investigated, with focus on the benthic and pelagic fish species. Concentrations of the selected trace elements have been analyzed in samples of water, plankton, benthic invertebrates and fish by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Concentration differences in the benthic and pelagic food chain of Lake Baikal have been investigated, with focus on benthic and pelagic fish species. In addition, spatial differences in the concentration of these potentially toxic elements between Selenga Shallows (possibly polluted site) and Listvyanka Bay (reference site) were included in the analysis to reveal potential anthropogenic impact on the lake.The comparative study revealed some concentration differences in water and biotic components at the two sampling locations. The concentration of Pb was significantly higher in water from the Selenga Shallows. However, several of the biota samples had highest concentrations of trace elements at Listvyanka Bay. This can be related to higher bioavailability of trace elements at Listvyanka Bay, possibly caused by lower abundance of natural ligands at this location. In both the pelagic and benthic food chain of Lake Baikal, Hg showed indication of biomagnification while As, Cd and Pb seemed to be biodiluted. When comparing fish inhabiting the pelagic and benthic food chain, differences in concentrations of As and Hg were identified. The As concentrations were twice as high in pelagic fish, while the benthic fish had seven times higher Hg content compared to pelagic fish. The observed concentration differences of As and Hg may be related to such as different complexity of the two food chains, different feeding strategies and habitat. Based on the tissue Se:Hg molar ratio there is no risk of Hg induced toxicity in the endemic fish species of Lake Baikal at the present. In general, the present study confirms low concentrations of potentially toxic chemical elements (As, Cd, Hg, Pb and Se) in Lake Baikal in comparison to other freshwater ecosystems.
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27

Johnsen, Ida Egge. "The Effect of Persistent Organic Pollutants on Thyroid Hormone Levels in Arctic Breeding Kittiwake (Rissa tridactyla)." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13743.

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Black-legged kittiwakes (Rissa tridactyla) breeding in the Arctic, are exposed to annual fluctuating environmental conditions. The impact of inter-year variations in environmental conditions on the blood concentrations of persistent organic pollutants (POPs) was examined in black-legged kittiwakes breeding in Kongsfjorden, Svalbard. In addition, it was examined if inter-year variations in concentration of POPs were affecting circulating thyroid hormone (TH) levels. Blood samples were collected from breeding kittiwakes during the incubation period in 2008 (n=46) and 2009 (n=31), two different years in respect of environmental conditions. The whole blood samples were analyzed for POPs: polychlorinated biphenyls (PCBs; PCB-28, -52, -99, -118, -101, -138, -153, 180, -183, -187, -194), hexachlorobezene (HCB), hexachlorocyclohexan (HCH), dichlorodiphenyltrichloroethane (p,p’-DDT), dichlorodiphenyldichloroethylene (p,p’-DDE) oxychlordane, cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, heptachlor, heptachloroepoxid, and mirex, using gas chromatography mass spectrometry. Plasma was analysed for concentrations of total triiodothyronine (T3), using radioimmunoassay. Associations between variables of POPs and T3 were analysed using univariate statistics. Biometric measurements of the kittiwakes; body mass, skull length, and wing length where included in the statistical analysis, together with calculated BC (BC; body mass controlled for body size). Associations between the variables were analysed using multivariate statistics. The PCBs were the dominant contaminants in both 2008 and 2009. The three major constituents in the kittiwakes were PCB-153, followed by PCB-138 and PCB-180. Even though the body condition of the kittiwakes was significant poorer in 2009 compared to 2008, the concentrations of PCBs and DDE did not differ between 2008 and 2009. The concentration (ng/g wet weight [w.w.]) of HCB and oxychlordane were significant higher in 2009 compared to 2008. There was a strong negative association between HCB and body condition of the kittiwakes. Also the concentration of oxychlordane was negative correlated to body condition. Thus, kittiwakes with poor body condition had higher levels of HCB and oxychlordane. Additionally, HCB, oxychlordane and PCB-183 were positively associated with egg-laying date, while body condition was negatively correlated to egg-laying date. The results showed that kittiwakes with a poor body condition and thus, high levels of HCB and oxychlordane, were associated with late breeding. The low body condition in 2009 indicated poor food availability and unfavourable conditions for the kittiwakes that year.
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28

Helsingen, Even Buvarp. "Bioaccumulation of chemical elements in grey seals (Halichoerus grypus) from the Baltic Sea." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14591.

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Concentrations of Ag, As, B, Ba, Bi, Ca, Cd, Ce, Co, Cs, Cu, Dy, Er, Fe, Ga, Ge, Hg, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, S, Sb, Se, Si, Sm, Sn, Sr, Tb, Th, Tl, V, W, Y, Yb and Zn in the livers of grey seals obtained from stranded, hunted and by-caught animals from the Swedish and Polish Baltic coasts were determined by ICP-MS. Stable isotope analysis of &#948;13C and &#948;15N was applied to link chemical element concentrations to feeding preferences (pelagic vs. benthic) and trophic position of the seals, respectively. Isotopic ratios in the seals increased in seals from the north towards the southern Baltic Sea, with markedly higher isotopic signatures in seals inhabiting the Polish coast . Analysis of covariance revealed differences in chemical element concentrations between areas for As, B, Cu, Ni, Rb, Sr, Tl with most of these elements exhibiting higher concentrations in seals from the southern Baltic Sea. Additionally age related differences in concentrations of several trace elements were found. Silver, B, Bi, Cd, Co, Hg, Mo, Sb, Se, Sn, V and Zn and the rare earth elements (REE) were found to increase with age. The role of Se in detoxification of Hg was confirmed by high correlation between these two elements (r = 0.99, p < 0.0001). Significantly higher Se:Hg molar ratio were observed in yearlings compared to juvenile and adult seals . Several other elements also revealed statistically significant interrelationships, especially pronounced for the REEs.
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29

Haugerud, Anja Johansen. "Levels and Effects of Organohalogenated Contaminants on Thyroid Hormone Levels in Glaucous Gulls (Larus hyperboreus) from Kongsfjorden, Svalbard." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15014.

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The glaucous gull (Larus hyperboreus) is one of the largest flying top predators in the Arctic and is exposed to rather high levels of different persistent organohalogenated contaminants (OHCs). The present study investigated whether the serum thyroid hormone (TH) levels in female glaucous gulls breeding in Kongsfjorden (79oN) may be affected by the various OHCs. A slight decrease in traditional OHCs, like polychlorinated biphenyls (PCBs) and some pesticides have been reported over the last decade, while increasing levels of new and emerging compounds like polybrominated diphenyl ethers (PBDEs) and perfluoroalkyl substances (PFASs) are detected in Arctic marine and terrestrial wildlife. Although further production of some possible endocrine disruptive chemicals have been banned by many nations, the chemicals persist, move throughout the biosphere and are potentially harmful to exposed wildlife and biota.After 35 years of contaminant research, the Svalbard glaucous gull function as a bioindicator species. Previous assessments have concluded that OHC levels were high enough to be of concern for a number of physiological effects, among them endocrine alterations. However, this is to my knowledge the first biomarker study on levels of THs in breeding glaucous gulls from Kongsfjorden. Plasma from 19 nesting female glaucous gulls was analysed for PCBs, organochlorinated pesticides (OCPs) (such as dichlorodiphenyltrichloroethane [DDT] and chlordanes) and their metabolites, PBDEs and PFASs. Total and free ranging THs were quantified using radioimmuno assay (RIA). Multivariate statistics were used to investigate the relationships between the TH levels and the explanatory variables.The PCBs represented the most pervasive compound group in the present study, as 61.3 % of the total contaminant burden in female glaucous gulls. The other contaminant groups contributed as follows: &#931;DDTs (17.5 %) > &#931;PFASs (14.8 %) > HCB (2.9 %) > &#931;CHLs (2.7 %) > &#931;PBDE (0.8 %) > &#931;HCH (0.1 %). Several of the PFASs correlated significantly with the THs. Significant correlations were found between several of the long-chain Perfluoroalkyl carboxylates (PFCAs) and THs. Surprisingly, even though the PFCAs represented only 2.8 % of the total contaminant load in the present study, the PFCAs represented the most important variables explaining the variation in THs.
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30

Kristoffersen, Siv. "Organohalogenated Contaminants in Eggs of Snow Buntings (Plectrophenax nivalis) from Human Settlements in Svalbard." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16811.

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Contaminants in the Arctic environment are mainly transported from lower latitude areas by atmospheric transport. However, the Russian settlements (Barentsburg and Pyramiden) in Svalbard have shown to be heavily influenced by local pollution of polychlorinated biphenyls (PCB), as high concentrations have been found in vegetation, soil and sediments. The Norwegian settlements (Longyearbyen and Ny-Ålesund) are to a lesser extent influenced by local pollution of PCB. Birds have been utilized as sentinels for environmental pollution in several studies, as the use of bird-eggs is considered as a non-invasive method. The aim of this study was to investigate whether the snow bunting (Plectrophenax nivalis) is influenced by local pollution of PCB in the Russian settlements. During the 2010 field season and the 2011 field season, 32 eggs of snow buntings were collected in Longyearbyen (n=8), Ny-Ålesund (n=8), Barentsburg (n=9) and Pyramiden (n=7). The analysis was conducted at the Norwegian Institute of Air Research (NILU) in Tromsø. The eggs were analyzed for PCBs, organochlorinated pesticides (OCPs), brominated diphenyl ethers (PBDE) and perfluoroalkylated compounds (PFASs). The results showed that PCBs were the most abundant contaminant group in the Russian settlements, while PFASs was the most abundant contaminant group in the Norwegian settlements. Significant higher concentrations (ng/g wet weigth) of &#8721;7PCB (sum of the seven most common PCBs) were found in the eggs from the Russian settlements (Barentsburg and Pyramiden) than in the eggs from the Norwegian (Longyearbyen and Ny-Ålesund). Further on, the PCB congener composition in the eggs was comparable with the technical PCB-mixtures previous used in the Russian settlements. The results thus indicate influence of local pollution of PCB in eggs of snow buntings in the Russian settlements. Further on, local influence of dichlorodiphenyldichloroethylene (p,p’-DDE) and PFASs cannot be excluded. However, the contaminant burden of hexachlorobenzen (HCB), trans-nonachlor, p,p’-DDE and PFASs in the eggs of snow buntings in Svalbard are mainly explained by; I: atmospheric transport of contaminants to the Arctic environment, II: transport of contaminants by sea birds, III: exposure during migration, IV: exposure in overwintering areas. The concentration of organohalogenated compounds (OHCs) in eggs of snow buntings in this study is considerable lower than concentrations in previously studies that have reported to cause adverse effect in other bird species. Further are the concentrations of OHCs in this study in general lower when compared with other studies on Svalbard seabirds. However, it should be noted that the concentration of &#8721;PCB in eggs of snow buntings is comparable with previous studies on Svalbard seabirds. The results in this study indicate that the snow bunting may be utilized as a sentinel of local pollution in Svalbard in the future.
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31

Lakså, Solveig Margrethe B. "Effects of environmental exposure: Interplay between helix-distorting and oxidative DNA lesions and their repair." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16814.

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DNA lesions are introduced in all living organisms every day, both via endogenous processes and by exposure to an array of DNA damaging agents. DNA lesions require repair for the sustenance of life. Base excision repair (BER) and nucleotide excision repair (NER) are DNA repair pathways involved in removal of oxidative DNA lesions and helix-distorting DNA lesions, respectively. Several studies suggest interactions or crosstalk between these pathways, involving overlapping activities for removal of the same types of DNA lesions but also interference between repair pathways.Non-repaired DNA lesions are regarded as an important risk factor in the pathogenesis of certain conditions and diseases. It is important to gain insight in the interplay between DNA damaging agents, DNA lesions and their DNA repair pathways, since this may be related to the overall sensitivity of cells to combined exposure to endogenous or exogenous agents.In the present study, we aimed at studying combined exposures to environmental genotoxicants at low doses, and potential interactions between DNA repair pathways. The two genotoxicants lead to DNA lesions that are processed via two different DNA repair pathways. We studied the impact of low levels of oxidative stress on the repair of low levels of helix-distorting DNA lesions; and – vice versa - the impact of low levels of helix-distorting DNA lesions, on the repair of low levels of oxidative DNA lesions. We induced the different types of lesions in cells of different genetic background, to study whether a lack of repair of oxidative DNA lesions could also affect the repair of helix-distorting lesions. For this purpose, we utilised wild type mouse embryonic fibroblasts (Ogg1+/+ MEFs), and a MEF cell line deficient in the repair protein 8-oxoguanine DNA glycosylase (Ogg1) (Ogg1-/- MEFs). The Ogg1 gene is involved in the removal of certain oxidized DNA lesions via BER. Ogg1+/+ MEFs exposed to a DNA helix-distorting agent did not show perturbed repair of induced oxidative DNA lesions, suggesting that low levels of NER-sensitive DNA damage do not influence BER. Furthermore, the repair of helix-distorting DNA lesions in wild type MEFs (Ogg1+/+) or Ogg1-/- MEFs was not perturbed by a (single) low level exposure to oxidative stress, suggesting that reactive oxygen species (ROS) or BER-sensitive DNA damage do not influence the repair of low levels of helix-distorting DNA lesions. However, Ogg1+/+ MEFs showed more efficient repair of helix-distorting DNA lesions compared to Ogg1-/- MEFs, regardless of the level of oxidative lesions present in the DNA. This finding suggests that the BER-related repair protein Ogg1 may play a role also in the repair of NER-sensitive helix-distorting DNA lesions.In conclusion, low levels of oxidative stress or helix-distorting DNA lesions did not seem to perturb cellular repair of low levels of helix-distorting DNA lesions or oxidized DNA lesions, respectively, in wild type or Ogg1-deficient MEFs. A crosstalk between Ogg1 and repair of helix-distorting DNA lesions was however observed, suggesting an interplay between BER and NER with respect to the repair of NER-sensitive DNA damage.
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32

Hansen, Ingunn Tjelta. "Effects of Persistent Organic Pollutants on Reproductive Hormones in Male Polar Bears (Ursus Maritimus) from Svalbard." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16822.

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PCBs and other environmental contaminants have been found to have an effect on steroid hormones in polar bears (Ursus maritimus). The purpose of this study was to investigate the effect of persistent organic pollutants (POPs) on the steroidogenesis in male polar bears from Svalbard. Blood samples from male polar bears (n=23) were collected at Svalbard, Norway in April 2008 as a part of the International Polar Year-project, BearHealth. The sampled individuals were between 3-21 years, where individuals under 5 years (n=6) were categorized as subadults. Serum and plasma samples were analysed for steroid hormones (pregnenolone (Pre), progesterone (Pro), androstenedione (AN), dehydroepiandrosterone (DEA), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), estradiol-17&#945; (E2-&#945;) and estradiol-17&#946; (E2-&#946;)) with a recently developed gas chromatography-tandem mass spectrometry (GC-MS/MS) determination method, whereas cholesterol concentrations were measured by Reflotron&#63720;. The environmental contaminants (HCB, &#945;&#8208;HCH, &#946;&#8208;HCH, oxychlordane, trans&#8208;nonachlor, mirex, p,p'-DDE, p,p'&#8208;DDT, PCB&#8208;47, PCB&#8208;74, PCB&#8208;99, PCB&#8208;101, PCB&#8208;128, PCB&#8208;137, PCB-138, PCB&#8208;153, PCB&#8208;170, PCB&#8208;180, PCB&#8208;183, PCB&#8208;187, PCB&#8208;194, PCB&#8208;206, PCB-105, PCB-114, PCB-118, PCB-156, PCB-157, PCB-167, PCB-189, 4'-OH-CB107, 4'-OH-CB130, 3'-OH - CB138, 4&#8208;OH&#8208;CB146, 4'-OH&#8208;CB159, 4'-OH-CB172, 3'-OH-CB180, 4-OH&#8208;CB187, BDE-47, BDE-154) included in this study were analysed by gas chromatography-electron capture detection (GC-ECD) or GC/MS. Multivariate regression analysis, principal component analysis (PCA) and orthogonal partial least squares (OPLS) regression, were performed to investigate the influence of the contaminants on the steroid hormones in the adult individuals. Only the OPLS model with DHT as the response variable was significant. Most of the environmental contaminants had a significantly negative contribution on the variation in dihydrotestosterone concentrations. Based on the statistical analyses, the poly-ortho PCBs and HCB might be more central in explaining the variation in DHT concentrations, while PBDEs and OH-PCBs seems to be less important. Androstenedione were found to be the androgen with highest concentration in circulating blood from male polar bears, unlike other studies on mammals where testosterone has been found to be the most abundant androgen. The high level of AN might be connected to the negative effect of contaminants on DEA levels. The GC-MS/MS method applied in the current study can successfully compete with other frequently used determinations methods, such as RIA. The method is appropriate for the study several steroid hormones and their precursors in male polar bears and can be recommended for studies investigating the effect of persistent organic pollutants on the on the steroidogenesis.
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33

Liu, Xixi. "Effects of Ammonia and Organic Ligands to Cadmium (Cd) Toxicity on Marine Phytoplankton." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16824.

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The effects of ammonia to Cd toxicity on marine phytoplankton have been studied. The phytoplankton biomass was significantly increased at higher ammonia flux after high Cd level exposure, which indicated high ammonia decreased Cd toxicity on phytoplankton. In addition, DGT labile Cd concentration was linear decreased with increasing ammonia flux in day 8, while DGT labile Cd concentration was increased at higher ammonia flux in day 12. Cd complexation capacity in seawater of Cd treatment was higher over 100 times than Cd complexation capacity in seawater of without Cd treatment. And high ammonia increased Cd complexation capacity in seawater after high Cd exposure in day 8, while Cd complexation capacity in seawater of Cd treatment was decreased due to high ammonia in day 12. Therefore, ammonia influences the amount of DOM released by phytoplankton and the Cd complexation with organic ligands, and finally leads to affect Cd bioavailability and toxicity on phytoplankton.
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34

Hellstrøm, Kaja Cecilie. "Comparison of the Composition of Chemical Elements in the Liver of Ringed Seal (Phoca hispida) from three different populations." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19689.

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The ringed seal (Phoca hispida) is a circumpolar Arctic species, with several subspecies and –populations. One subspecies, Phoca hispida botnica, is found in the Baltic Sea. Large ecological differences between these regions may cause variations of trophic positioning and chemical composition in tissues among the inhabiting ringed seal populations. The Baltic Sea is one of the worlds’ most polluted seas, and the metal pollution in this area may be problematic for Baltic ringed seals. Liver samples from juvenile ringed seals (1-3 years) from three distinct populations, in northwest Greenland, East Greenland and the Baltic Sea were collected during 2008-09. Concentrations of 42 chemical elements, including As, Cd, Hg, Pb and Se, were determined using HR-ICP-MS. Stable isotope analysis (IRMS) of &#948;13C and &#948;15N were conducted in order to reveal population differences in feeding preferences (pelagic versus benthic species) and trophic positioning, respectively. Significant differences for &#948;13C and &#948;15N were found between all three populations, and the Greenland populations showed benthic preferences and higher trophic positioning relative to the Baltic Sea. The chemical element analysis revealed spatial differences between the Baltic Sea population and either one or both of the Greenland populations for several elements. However, none of the elements of concern in the Baltic Sea were present at significantly higher concentrations in the Baltic Sea population compared to the two Greenland populations. The lower trophic positioning and preferred pelagic foraging of Baltic ringed seals contribute to protect them from impacts of their polluted habitat.
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35

Zhang, Jinwen. "The mouse oocyte as a model in reproductive toxicology studies /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-163-0/.

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36

Moresco, Rafaela Maria [UNESP]. "Pigmentação testicular e ciclo reprodutivo anual de Physalaemus cuvieri Fitzinger, 1826 em populações de biomas distintos." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/100513.

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Made available in DSpace on 2014-06-11T19:30:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-04-26Bitstream added on 2014-06-13T19:01:02Z : No. of bitstreams: 1 moresco_rm_dr_sjrp_parcial.pdf: 106475 bytes, checksum: d09b090350ada960f17c7c2d58ad3eb2 (MD5)
A reprodução pode ser descrita como o conjunto de atributos fisiológ icos, morfológicos e comportamentais que permitem o sucesso de uma espécie através da máxima descendência sob condições ambientais específicas. Em anfíbios, além de sujeito a um controle hormonal, e considerando o aporte genético, o ciclo reprodutivo é também influenciado por fatores ambientais que determinam o ciclo ga metogênico ao longo de um ano. O presente trabalho teve como objetivo estimar a di versidade genética em duas populações de P. cuvieri pertencentes aos biomas de Mata Atlânti ca e do Cerrado com o marcador molecular ISSR ( Inter Simple Sequence Repeats ). Além disso, foi caracte rizado o ciclo reprodutivo destas populações, relacionando as variações morfológicas gonadais com os fatores climáticos precipitação, temperatura, umidade relativa do ar e velocidade do vento, através de uma Análise de Correspondência Canônica, bem como relacionar a quantidade de pigmentos presente nos testículos com os períodos pré-reprodutivo, reprodutivo e regenerativo através de ANOVA. Ta mbém se analisou em indivíduos de Eupemphix nattereri a relação entre a espermiogênese e a qua ntidade de pigmentação testicular. As populações de P. cuvieri pertencentes aos dois biomas re velaram índice de diferenciação genética (FST ) > 0.288, o que mostra que es tas duas populações são altamente diferenciadas geneticamente. Foram caracter izados 7 tipos celu lares representando o epitélio germinativo. A variância total ao longo do ciclo reprodutivo foi de 23 %, com os dois primeiros eixos responsáveis, respectivamente, por 68,7% e 10,2% da variância total acumulada na média ponderada dos tipos celula res com relação às 4 variáveis ambientais analisadas. O teste de permutação de Monte Carlo indicou que os tipos celulares e a...
Reproduction can be described as the set of physiological, mo rphological, and behavioural attributes that allow for the success of a species through maximum offspring under specific environmental conditions. In amphibians, as well as being under hormonal control, and in view of their genetic constitution, the reproductive cycle is also influenced by environmental factors that determine the ga metogenetic cycle throughout the year. The aim of this study was to characterize the reproductive cycle of Physalaemus cuvieri in populations from the Mata Atlântica region and the Ce rrado region, comparing the morphological gonad variations to the climatic factors of precipita tion, temperature, relative humidity and wind speed, through a Ca nonical Correspondence Analysis, as well as comparing the quantity of pigments presen t in the testis with the pre-reproductive, reproductive and regenerative periods usi ng the ANOVA, and estimating the genetic diversity between the populations of the two biomes with genetic markers ISSR ( Inter Simple Sequence Repeats). The relationship between spermatogenesis and the quantity of testicular pigmentation in individuals of Eupemphix nattereri has also been analyzed... (Complete abstract click electronic access below)
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37

Moresco, Rafaela Maria. "Pigmentação testicular e ciclo reprodutivo anual de Physalaemus cuvieri Fitzinger, 1826 em populações de biomas distintos /." São José do Rio Preto, 2013. http://hdl.handle.net/11449/100513.

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Orientador: Classius de Oliveira
Banca: Lia Raquel de Souza Santos
Banca: Fernanda Cristina Alcantara dos Santos
Banca: Alexandre Ninhaus Silveira
Banca: Selma Maria Almeida Santos
Resumo: A reprodução pode ser descrita como o conjunto de atributos fisiológ icos, morfológicos e comportamentais que permitem o sucesso de uma espécie através da máxima descendência sob condições ambientais específicas. Em anfíbios, além de sujeito a um controle hormonal, e considerando o aporte genético, o ciclo reprodutivo é também influenciado por fatores ambientais que determinam o ciclo ga metogênico ao longo de um ano. O presente trabalho teve como objetivo estimar a di versidade genética em duas populações de P. cuvieri pertencentes aos biomas de Mata Atlânti ca e do Cerrado com o marcador molecular ISSR ( Inter Simple Sequence Repeats ). Além disso, foi caracte rizado o ciclo reprodutivo destas populações, relacionando as variações morfológicas gonadais com os fatores climáticos precipitação, temperatura, umidade relativa do ar e velocidade do vento, através de uma Análise de Correspondência Canônica, bem como relacionar a quantidade de pigmentos presente nos testículos com os períodos pré-reprodutivo, reprodutivo e regenerativo através de ANOVA. Ta mbém se analisou em indivíduos de Eupemphix nattereri a relação entre a espermiogênese e a qua ntidade de pigmentação testicular. As populações de P. cuvieri pertencentes aos dois biomas re velaram índice de diferenciação genética (FST ) > 0.288, o que mostra que es tas duas populações são altamente diferenciadas geneticamente. Foram caracter izados 7 tipos celu lares representando o epitélio germinativo. A variância total ao longo do ciclo reprodutivo foi de 23 %, com os dois primeiros eixos responsáveis, respectivamente, por 68,7% e 10,2% da variância total acumulada na média ponderada dos tipos celula res com relação às 4 variáveis ambientais analisadas. O teste de permutação de Monte Carlo indicou que os tipos celulares e a... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Reproduction can be described as the set of physiological, mo rphological, and behavioural attributes that allow for the success of a species through maximum offspring under specific environmental conditions. In amphibians, as well as being under hormonal control, and in view of their genetic constitution, the reproductive cycle is also influenced by environmental factors that determine the ga metogenetic cycle throughout the year. The aim of this study was to characterize the reproductive cycle of Physalaemus cuvieri in populations from the Mata Atlântica region and the Ce rrado region, comparing the morphological gonad variations to the climatic factors of precipita tion, temperature, relative humidity and wind speed, through a Ca nonical Correspondence Analysis, as well as comparing the quantity of pigments presen t in the testis with the pre-reproductive, reproductive and regenerative periods usi ng the ANOVA, and estimating the genetic diversity between the populations of the two biomes with genetic markers ISSR ( Inter Simple Sequence Repeats). The relationship between spermatogenesis and the quantity of testicular pigmentation in individuals of Eupemphix nattereri has also been analyzed... (Complete abstract click electronic access below)
Doutor
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38

Davis, Emma Louise. "Investigations of factors that influence the genotoxicity of environmental chemicals." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270808.

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39

Basu, Amitabha Spotila James R. "Development of a 'genetic signature of environmental lead exposure' in wild Peromyscus using combinatorial data from cDNA microarrays and blood metabolites /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2796.

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40

Dahl, Ulrika. "Integrating biochemical and growth responses in ecotoxicological assays with copepods." Doctoral thesis, Stockholm University, Department of Applied Environmental Science (ITM), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8218.

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The understanding of effects of chemical exposure in nature is lagging behind. Predictions of harmful effects of chemicals on aquatic organisms rely mainly on ecotoxicity tests. To improve the understanding of the biological linkage between the cellular and organismal responses to a chemical in an ecotoxicological test, the major aim of this doctoral thesis was to investigate the usefulness of two biochemical endpoints, contents of RNA and ecdysteroids, by incorporating them with life-history traits of copepods (Crustacea). To do so, the two methods needed to be established at our laboratory. Both biochemical methods are more commonly used in basic biological research, but I here present its usefulness in ecotoxicological testing. It was found that individual RNA content as a biochemical endpoint was significantly altered in the brackish water harpacticoid copepod Nitocra spinipes when exposed to the pesticide Lindane (paper IV) and low concentrations (0.16

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41

Niyonzima, Francois Niyongabo. "Bioaccumulation and ecotoxicology of b-methylamino-l-alanine (BMAA) in model crop plants." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1475.

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Cyanobacteria are known to produce a variety of toxic compounds. β-N-methylamino-L-alanine (BMAA) is one of the neurotoxins produced by most cyanobacteria. BMAA has been implicated in amyotrophic lateral sclerosis / Parkinsonism dementia complex (ALS / PDC) and was suggested to contribute to this pathology after biomagnification and slow release of BMAA from a protein associated form. The uptake and accumulation of BMAA by the aquatic macrophyte Ceratophyllum demersum has recently been shown, but the consumption of aquatic macrophytes by humans is not typical. The uptake by, and accumulation in, crop plants (Nasturtium officinale and Daucus carota) was therefore investigated so as to establish the existence of any risk to humans from the consumption of plants irrigated with water from dams with high cyanobacterial biomass and therefore high BMAA levels. After the exposure to the BMAA through the growth medium, BMAA had no effect on growth and development of N. officinale and D. carota. The uptake and bioaccumulation of BMAA was observed in N. officinale and D. carota, and was found to be concentration-dependent. Both free and bound cellular BMAA was detected following BMAA exposure through the growth medium. The photosynthetic apparatus of N. officinale was not significantly damaged. The uptake and accumulation of BMAA in edible terrestrial plants may constitute another route of human exposure to BMAA; it may now be prudent to avoid spray irrigation of edible plants with waters from dams with high cyanobacterial biomass and therefore high BMAA levels. After uptake by plants, the cyanotoxins may induce oxidative stress. A recent study showed that BMAA has a significant inhibitory effect on the oxidative stress enzymes in C. demersum. Therefore, the toxicological effects on selected plants were investigated by a range of biochemical enzyme assays in order to establish the plant stress response to exogenous BMAA. The inhibition of antioxidant enzymes upon exposure of N. officinale to BMAA through the growth medium was observed. The inhibition of antioxidant defence enzymes by BMAA correlated with the BMAA bioaccumulation in N. officinale. Further investigations are needed to analyze the uptake, accumulation, and ecotoxicology of BMAA in other crop plants, and to examine the fate of BMAA in these plants particularly its distribution and metabolism.
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42

Kratchman, Jessica. "Predicting Chronic Non-Cancer Toxicity Levels from Short-Term Toxicity Data." Thesis, The George Washington University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10263969.

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This dissertation includes three separate but related studies performed in partial fulfillment of the requirements for the degree of Doctor of Public Health in Environmental and Occupational Health. The main goal this dissertation was to develop and assess quantitative relationships for predicting doses associated with chronic non-cancer toxicity levels in situations where there is an absence of chronic toxicity data, and to consider the applications of these findings to chemical substitution decisions. Data from National Toxicology Program (NTP) Technical Reports (TRs) (and where applicable Toxicity Reports), which detail the results of both short-term and chronic rodent toxicity tests, have been extracted and modeled using the Environmental Protection Agency’s (EPA’s) Benchmark Dose Software (BMDS). Best-fit minimum benchmark doses (BMDs) and benchmark dose lower limits (BMDL) were determined. Endpoints of interest included non-neoplastic lesions, final mean body weights and mean organ weights. All endpoints were identified by NTP Pathologists in the abstract of the TRs as either statistically or biologically significant. A total of 41 chemicals tested between 2000 and 2012 were included with over 1700 endpoints for short-term (13 week) and chronic (2 year) exposures.

Non-cancer endpoints were the focus of this research. Chronic rodent bioassays have been used by many methodologies in predicting the carcinogenic potential of chemicals in humans (1). However, there appears to be less emphasis on non-cancer endpoints. Further, it has been shown in the literature that there is little concordance in cancerous endpoints between humans and rodents (2). The first study, Quantitative Relationship of Non-Cancer Benchmark Doses in Short-Term and Chronic Rodent Bioassays (Chapter 2), investigated quantitative relationships between non-cancer chronic and short-term toxicity levels using best-fit modeling results and orthogonal regression techniques. The findings indicate that short-term toxicity studies reasonably provide a quantitative estimate of minimum (and median) chronic non-cancer BMDs and BMDLs.

The next study, Assessing Implicit Assumptions in Toxicity Testing Guidelines (Chapter 3) assessed the most sensitive species and species-sex combinations associated with the best-fit minimum BMDL10 for the 41 chemicals. The findings indicate that species and species-sex sensitivity for this group of chemicals is not uniform and that rats are significantly more sensitive than mice for non-cancerous outcomes. There are also indications that male rats may be more than the other species sex groups in certain instances.

The third and final study, Comparing Human Health Toxicity of Alternative Chemicals (Chapter 4), considered two pairs of target and alternative chemicals. A target is the chemical of concern and the alternative is the suggested substitution. The alternative chemical lacked chronic toxicity data, whereas the target had well studied non-cancer health effects. Using the quantitative relationships established in Chapter 2, Quantitative Relationship of Non-Cancer Benchmark Doses in Short-Term and Chronic Rodent Bioassays, chronic health effect levels were predicted for the alternative chemicals and compared to known points of departure (PODs) for the targets. The findings indicate some alternatives can lead to chemical exposures potentially more toxic than the target chemical.

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43

Ownby, David R. "Predicting metal interactions with a novel quantitative ion character -activity relationship (QICAR) approach." W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539616800.

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Environmental toxicologists adopted QSARs from pharmacology fairly early on to predict organic contaminant toxicity. In contrast, models relating metal ion characteristics to their bioactivity remain poorly explored and underutillized. Quantitative Ion Character-Activity Relationships (QICARs) have recently been developed to predict metal toxicity. The QICAR approach based on metal-ligand binding tendencies has been applied to a wide range of effects, species, and media on a single metal basis. In previous single metal studies, a softness parameter and the ; log of KOH ; were the ion qualities with the highest predictive value for toxicity. Here, QICAR modeling was brought a step further to predict toxicity of binary metal mixtures. Using the MicrotoxRTM bioassay, the interaction of binary mixtures of metals (Co, Cu, Mn, Ni, and Zn) is quantified using a linear model with an interaction term. A predictive relationship for metal interaction between pairs of metals and the difference in the softness parameter was developed. The interaction of binary mixtures of Co, Cu, Ni, and Zn was quantified using a linear model for nematode (Caenorhabditis elegans) exposures. Contrasting with earlier studies, the difference in polarizing power (Z2/r) between metal ions was the best ion characteristic for predicting interaction coefficients. Current risk assessment methods sum toxic units, assuming that all mixtures act in an additive fashion. General problems with this method are demonstrated utilizing data from the MicrotoxRTM metal mixture tests. An alternative, more accurate, method for summing toxicities with proportions instead of toxic units is illustrated. This study supports the hypothesis that general prediction of metal interactions from ion characteristics is possible. It is important to realize that even with the preliminary success of these models that additional work with metals of different valences and sizes might affect the accuracy of metal interaction predictions. Careful thought and examination of known modes of single metal toxicity should be considered when developing future quantitative metal interaction models.
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44

Venkatraman, Padma T. "Comparative Toxicity of Creosote and Creosote Contaminated Sediments." W&M ScholarWorks, 1994. https://scholarworks.wm.edu/etd/1539617669.

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45

van, den Hurk Peter. "Interactive effects of cadmium and benzo(a)pyrene in mummichog (Fundulus heteroclitus)." W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539616888.

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When animals are exposed to mixtures of environmental pollutants, it is generally assumed that the toxic effects of the individual components are additive. However, examples of synergistic and antagonistic effects have been described. to study the mechanisms of interaction between a metal and a polycyclic aromatic hydrocarbon, mummichog (Fundulus heteroclitus) were injected with combinations of cadmium (Cd) and benzo (a) pyrene (BP). Measured effect parameters were: mortality, BP-metabolite production in isolated hepatocytes and microsomes, hepatic induction of CYP1A (the BP metabolizing enzyme) and metallothionein (the Cd binding protein), and biliary excretion of BP-metabolites. The mortality data demonstrated that both synergistic and antagonistic effects can occur. A Cd dose of 0.32 mg/kg significantly reduced the expected mortality caused by BP. In contrast, a BP dose of 10 mg/kg significantly increased the toxicity of Cd above the expected mortality. to study the mechanisms of these interactive effects, liver cells (hepatocytes) were isolated from fish that were previously injected with combinations of Cd and BP. These cells were exposed to radiolabeled BP to study the rate of BP metabolism, and the formation of BP-metabolites. Cadmium exposure had an overall inhibiting effect on the metabolism of BP. No effects of Cd were observed on the formation of individual metabolites. to distinguish between direct interference of Cd with CYP1A at the active site versus indirect interference by inhibiting CYP1A induction, microsomal preparations were evaluated for enzyme activity and enzyme concentration. While there was no direct effect of Cd on enzyme catalytic activity, there was an effect on CYP1A production. The demonstrated inhibition of BP metabolism by Cd would suggest a reduced excretion of BP-metabolites. However, analysis of bile and water samples after fish were injected with radiolabeled BP demonstrated an enhanced biliary excretion of conjugated BP-metabolites under influence of Cd. Cadmium exposure caused a significant induction of hepatic metallothionein in the fish. When BP was dosed together with Cd, the induction of MT was inhibited. The hypothesis that reactive BP metabolites would compete with Cd for binding sites on MT could not be confirmed. There was no measurable binding of BP to MT.
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46

Chow, Jimmy T. "Environmental assessment for bisphenol-a and polycarbonate." Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/368.

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47

Albanese, Katie. "Photochemistry and Toxicity of Triclosan, Triclocarban, and their Photoproducts and Mixtures in Freshwater Systems." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468967416.

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48

Yeung, Wai Yin. "Environmental concentrations, toxicology, and development of new methods for extraction and mass balance analysis of perfluorinated compounds in environmental samples /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-bch-b2374960xf.pdf.

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Abstract:
Thesis (Ph.D.)--City University of Hong Kong, 2009.
"Submitted to Department of Biology and Chemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 211-239)
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49

Perissini, Bruna Nogueira. "Avaliação do potencial de degradação do herbicida diuron por fungos isolados de solo de canavial e suas tolerâncias aos metabólitos gerados /." São José do Rio Preto, 2015. http://hdl.handle.net/11449/127839.

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Abstract:
Orientador: Eleni Gomes
Banca: Elen Aquino Perpetuo
Banca: Dávila de Souza Zampieri
Resumo: Restaurar ecossistemas degradados por compostos xenobióticos é um dos desafios atuais, que implica no desenvolvimento de metodologias eficazes que minimizem os danos e não interfiram nos processos naturais. A biorremediação é uma tecnologia que utiliza organismos vivos e/ou seus derivados para eliminar ou reduzir os níveis de poluentes de um determinado ambiente. Dentro dessa proposta, o emprego dos fungos para a recuperação de áreas contaminadas com xenobióticos de variados grupos químicos, tem sido bastante explorado, em função de suas características biológicas e morfológicas, além de suas enzimas extracelulares. A ação de um microrganismo sobre um determinado composto é desejável no sentido da redução de sua complexidade química, entretanto, a geração de compostos intermediários mais tóxicos que o original pode ocorrer, exigindo a avaliação desses derivados metabólicos antes de se inferir sobre o uso de uma determinada técnica de biorremediação. O presente trabalhou teve como objetivo avaliar a degradação do herbicida diuron pelos fungos Trichoderma harzianum G15, Trichoderma virens F28, Cunninghamella elegans B06, Fusarium sp. B19, Aspergillus sp. G25, Aspergillus brasiliensis G08, Beauveria sp. 211 e Mortierella alpina F17, e tolerância aos metabólitos gerados. T. harzianum G15, T. virens F28 e C. elegans B06 foram capazes de degradar entre 12 e 43% de diuron, acumulando no meio de cultivo os metabólitos DCPMU e DCPU, e ausência de 3,4-DCA. Quando cultivados em meio contendo esses metabólitos em substituição ao diuron, não houve efeito inibitório sobre o crescimento dos fungos e a degradação dos metabólitos foi de 42 a 73% para DCPMU, 37 a 69% para DCPU, 15 a 100% para a 3,4-DCA e de 19 a 84% para diuron. A formação de diferentes metabólitos a partir de 3,4-DCA, como o 3,4-CAC e 3,4-DCNB indicou que os fungos possuem mecanismos enzimáticos distintos de biodegradação desse composto...
Abstract: Degraded ecosystems recovery is one of the current challenges, which implies the development of effective methodologies that minimize the damage and not interfere with natural bioprocesses. Bioremediation is a technology that utilizes living organisms and/or their derivatives to eliminate or reduce the pollutant levels in an environment. The use of fungi for biodegradation of xenobiotics of various chemical groups has been extensively explored, due to its biological and morphological characteristics, and their extracellular enzymes. The action of a microorganism on the pollutant compound is desired in order to reduce its chemical complexity, however, the generation of more toxic intermediate compounds than the original may occur, requiring the evaluation of these metabolite derivatives prior to infer the use of a determined bioremediation technique. This work aimed to evaluate the herbicide diuron degradation by Trichoderma harzianum G15, T. virens F28, Cunninghamella elegans B06, Fusarium sp. B19, Aspergillus sp. G25, A. brasiliensis G08, Beauveria sp. 211 e Mortierella alpina F17 and evaluate their tolerance and ability to metabolize those generated metabolites. T. harzianum G15, T. virens F28 and C. elegans B06 were able to degrade between 12 and 43% of diuron and accumulated in the culture medium DCPMU metabolites and DCPU but not 3,4-DCA. When grown in medium containing these metabolites to replace diuron, no inhibitory effect on the growth of fungi and the degradation of DCPMU was 42 to 73%, for DCPU from 37 to 69%, for 3,4-DCA from 15 to 100%, and for diuron 19 to 84%. The formation of different metabolites from 3,4-DCA, such as 3,4-CAC and 3,4-DCNB indicated that the fungi have different enzymatic mechanisms of biodegradation of such a compound. The metabolites detected in culture media allowed to suggest that diuron degradation followed the degradation following sequence: DCPMU, DCPU, 3,4-DCA, 4-CAC, CAC 3.4-and 3.4-DCNB ...
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50

Fernandes, Maria Eduarda Camilo. "Degradação química e fotoquímica do organofosforado paraoxona /." São José do Rio Preto, 2014. http://hdl.handle.net/11449/127613.

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Abstract:
Orientador: Marcelo de Freitas Lima
Coorientador: Lidia Maria de Almeida Plicas
Banca: Josefredo Rodriguez Pliego Junior
Banca: Luis Octávio Regasini
Resumo: Esse trabalho teve como objetivo o estudo da degradação de um organofosforado modelo, o 4-nitrofenil fosfato de dietila (paraoxona), por meio de reações fotoquímicas e químicas. O armazenamento ilegal, sua alta toxicidade e os métodos de degradação utilizados na eliminação de pesticidas levaram à necessidade de encontrar métodos de degradação alternativos para os mesmos. Com isso, no estudo fotoquímico as reações fotossensitizadas tipo II foram empregadas e a espécie reativa, oxigênio singlete, foi produzida a fim de degradar a paraoxona. Em paralelo aos experimentos, o estudo químico-computacional foi realizado a fim de fornecer subsídios para uma possível explicação sobre a reatividade das espécies analisadas. Por meio dos resultados dos cálculos realizados foi possível analisar os orbitais de fronteira, os quais forneceram informações preciosas sobre a inércia da paraoxona frente ao oxigênio singlete, sugerindo que efeitos indutivos e de ressonância no anel têm papel importante no mecanismo de reação. Já nos estudos químicos utilizou-se a hidroxilamina, um nucleófilo alfa, como meio de degradação. O método mostrou-se eficiente e com alta dependência do pH do meio reacional, onde os melhores resultados para a reatividade do nucleófilos foram encontrados na faixa de pH 6,27 a 11,49. Os estudos com diferentes concentrações de nucleófilo indicam que não há participação direta da água na etapa lenta do mecanismo de reação. A termodinâmica do processo reacional aponta com muita clareza para um mecanismo associativo, provavelmente do tipo SN2(P). Parâmetros de correlação entre pKa dos nucleófilos e velocidade mostram que a paraoxona é insensível à basicidade do nucleófilo, como atestado pelo valor de Brownsted igual a 0,02 para nucleófilos comuns. Contudo fica evidente o efeito alfa apresentado pela hidroxilamina e a metil hidroxilamina. Na presença de hidroxilamina a velocidade de...
Abstract: This work aimed to study the degradation of an organophosphorus model, the 4- nitrophenyl diethyl phosphate (paraoxon) through photochemical and chemical reactions. The illegal storing, their high toxicity and degradation methods used in the elimination of pesticides have led to the need to find alternative methods for the degradation thereof. Thus, the study photochemical reactions photosensitized type II were employed and the reactive species, singlet oxygen was produced to degrade paraoxon. In parallel to the experiments, the chemical and computational study was conducted to provide information for a possible explanation of the reactivity of the species analyzed. Through the results of calculations performed was possible to analyze the orbital border, which provided valuable information on the inertia of paraoxon against singlet oxygen, suggesting that inductive and resonance effects in the ring have an important role in the reaction mechanism. Already in chemical studies we used hydroxylamine, a nucleophile alpha like through degradation. The method was efficient and high pH dependence of the reaction medium, where the best results for the reactivity of nucleophiles were found in the pH range from 6.27 to 11.49. Studies with different concentrations of nucleophile does not indicate the direct participation of water in the slow step of the reaction mechanism. The thermodynamics of the reaction process very clearly points to an associative mechanism, probably the type SN2 (P). Correlation parameters between pKa of nucleophiles and speed show that paraoxon is insensitive to basicity of the nucleophile, as attested by Brownsted value equal to 0.02 for common nucleophiles. However it is evident the alpha effect presented by hydroxylamine and hydroxylamine methyl. In the presence of hydroxylamine degradation rates increased about 840 times comparing with its spontaneous hydrolysis
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