L'évaluation du risque lié aux contaminants est généralement basée sur des données collectées au cours d'essais monospécifiques (à une seule espèce). Par conséquent, les interactions entre espèces, bien qu'elles structurent les écosystèmes, ne sont pas prises en compte. Pour explorer les effets des contaminants sur la dynamique des espèces en interaction, cette thèse vise à modéliser le fonctionnement d'un microcosme de laboratoire de deux litres incluant trois espèces, la daphnie Daphnia magna, la lentille d'eau Lemna minor et la microalgue Pseudokirchneriella subcapitata, exposées à une contamination par le cadmium. La dynamique des trois espèces ainsi que leurs interactions et les effets du cadmium ont été décrits par un modèle mécaniste basé sur des équations différentielles ordinaires couplées. Les principaux processus intervenant dans ce microcosme de trois espèces ont donc été formalisés, notamment la croissance et la survie des daphnies, la croissance et la sédimentation des algues, la croissance des lentilles, le broutage des algues par les daphnies, la compétition interspécifique entre algues et lentilles et les effets du cadmium sur ces différents processus. Les paramètres du modèle ont été estimés par inférence bayésienne, en utilisant simultanément toutes les données issues de différentes expérimentations en laboratoire, réalisées au cours de la thèse spécialement pour cette étude / Contaminant risk assessment is generally based on data collected during single species bioassays (including only one species). As a consequence, interactions between species that occur in ecosystems are not taken into account. To investigate the effects of contaminants on interacting species dynamics, this thesis aims at modelling the functioning of a 2-L laboratory microcosm with three species, the daphnid Daphnia magna, the duckweed Lemna minor and the microalgae Pseudokirchneriella subcapitata, exposed to cadmium contamination. We modelled the dynamics of the three species, their interactions and the effects of cadmium using a mechanistic model based on coupled ordinary differential equations. The main processes occurring in this three-species microcosm were thus formalized, including growth and survival of daphnids, growth and settling of algae, growth of duckweeds, grazing of algae by daphnids, interspecific competition between the algae and duckweeds, and the effects of cadmium on these processes. We estimated model parameters by Bayesian inference, using simultaneously all the data issued from multiple laboratory experiments specifically conducted for this study during the thesis

Biologiska toxicitetstester utförs genom att exponera en testorganism för olika koncentrationer av kemikalier under en bestämd period. Det finns akuta toxicitetstester och kroniska. Resultat från akuta studier presenteras som EC50-värde (Effect Concentration, affecting 50 % of the population). Tester som används som underlag för riskbedömningar ska utföras på kvalitetsmässigt acceptabelt sätt som grundas på International Organization for Standardization (ISO) och Good Labaratory Practice (GLP). Syftet med studien var att studera toxisk inverkan av kaliumdikromat på encellig sötvattenalg, R. subcapitata, genom att räkna cellantal med två olika instrument: flödescytometer och automatisk cellräknare. Vidare att jämföra testernas EC50 medelvärde mot ISO 8692 angivet värde i precisions syfte och att utvärdera de båda räknemetoderna gällande precision och analystid. Kaliumdikromat användes för tillväxtinhibering vid toxicitetstest. EC50-resultaten visade ingen statistiskt signifikant skillnad mellan de båda instrumenten (p=0,47). Den akuta toxicitetsanalysens precision kunde bekräftas som giltig då båda mätmetoders EC50 medelvärden vid jämförelse med ISO 8692 värde befanns inom bestämda 95% konfidensintervallet. Vid jämförelse av studiens två mätningsmetoder, observerades större spridning kring medelvärdet i cellräknarens resultat, där tre EC50 värden hamnade utanför 95% CI. Däremot visade resultatet från flödescytometern mindre spridning och högre noggrannhet jämfört med cellräknarens. Studien visade att flödescytometer skulle kunna användas i framtida toxikologiska tester med encelliga alger, men det krävs flera upprepade försök för att bekräfta fördelar med analysen i flödescytometern. / Biological toxicity tests are performed by exposing a test organism to different concentrations of chemicals over a certain period of time. Results from acute studies are presented as EC50 (Effect Concentration, affecting 50% of the population). Tests used as a basis for risk assessments shall be performed in a quality acceptable way based on the International Organization for Standardization (ISO) and Good Laboratory Practice (GLP). The aim of this study was to study the toxic effect of potassium dichromate on unicellular green algae R. subcapitata, by counting cells with two different apparatus: flow cytometer and automatic cell counter. Additionally, to compare the EC50 mean values against the ISO 8692 value for control of test precision and to compare accuracy and analytical time of two methods. Potassium dichromate was used for growth inhibition in toxicity tests. The EC50 results showed no statistically significant difference between the two instruments (p = 0.47). The accuracy of acute toxicity analysis was confirmed as valid as both EC50 average measurement values compared to ISO 8692 value were found within the 95% confidence interval. When comparing the two methods of the study, greater spread was observed around the mean value in the cell count's results, where three EC50 values were outside 95% CI. The result of the flow cytometer had less spread and higher accuracy compared to the cell count. The study showed that flow cytometers could be used in future toxicological tests with algae, but several repeated tests are required to confirm the benefits of analysis with the flow cytometer.

Made available in DSpace on 2014-06-11T19:30:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-29Bitstream added on 2014-06-13T20:21:11Z : No. of bitstreams: 1 franca_jg_dr_jabo.pdf: 2251025 bytes, checksum: 4391181f6db61217e2ad4bea2e7f55fd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O objetivo deste estudo foi avaliar o potencial tóxico do permanganato de potássio (KMnO4) através da avaliação da toxicidade aguda (CL50;96 h) e crônica para a tilápia, Oreochromis niloticus e a ecotoxicidade desse composto através de ensaios com o microcrustáceo Ceriodaphnia dubia e com a microalga Pseudokirchneriella subcapitata. Para o teste de toxicidade aguda foram utilizados alevinos de tilápia (0,52 + 0,10g e 3,35 + 0,36 cm), expostos a seguintes concentrações: 0; 0,5; 1,0; 2,0; 4,0 e 6,0 mg.L-1 KMnO4. Os efeitos subletais do KMnO4 foram avaliados pelo do teste de toxicidade crônica, com um grupo controle e duas concentraçõesteste, utilizadas na aqüicultura para o manejo e controle de doenças (1,0 e 4,0 mg.L-1 KMnO4). Para este teste foram utilizadas tilápias (40 g) jovens, expostas por 30 dias, com amostragem de 10 indivíduos por tratamento, nos intervalos de 0, 7, 15 e 30 dias. Os biomarcadores avaliados no presente estudo foram: análises hematológicas, da atividade fagocítica, determinações da concentração de GSH, da atividade enzimática da GST, catalase e peroxidação lipídica e genótoxicas. No teste de toxicidade aguda, o baixo valor de CL50;96h (1,81 mg.L-1), sugere que esta espécie de peixe, nesta fase de desenvolvimento, apresenta grande sensibilidade ao composto. No teste de toxicidade crônica, os peixes expostos na concentração de 1 mg.L-1 de KMnO4 não apresentaram variações significativas nos parâmetros sanguíneos analisados quando comparados ao grupo controle. Na concentração de 4 mg.L-1, as alterações no quadro hematológico indicaram processo de hemólise e redução da atividade fagocítica em consequência da ação oxidante do KMnO4. Nas concentrações de 1 e 4 mg.L-1 KMnO4 houve redução significativa da capacidade fagocítica de macrófagos. Na análise bioquímica, somente a enzima GSH apresentou aumento significativo... / This study aimed know the toxic potential of the potassium permanganate (KMnO4) through the evaluation of the acute (LC50;96h) and cronic toxicity to tilapia, Oreochromis niloticus and the ecotoxicity of this compound through the assays with the microcrustacean Ceriodaphnia dubia and with microalgae Pseudokirchneriella subcapitata. For the acute toxicity test were used tilapia fingerlings (0.52 + 0.10g and 3.35 + 0.36 cm), exposed to concentrations: 0; 0.5; 1.0; 2.0; 4.0 and 6.0 mg.L-1 KMnO4. The sublethal effects of the KMnO4 were evaluated through cronic toxicity test, with a control group and two test concentrations, used in the aquaculture to management and control fishes diseases (1.0 and 4.0 mg.L-1 KMnO4). To this experiment were used with juvenile tilapia (40 g), exposed for 30 days, with samples of 10 individuals from each treatment at intervals of 0, 7, 15 and 30- days. The biomarkers evaluated in this present study were: hematological analysis, phagocytic activity, determination of GSH concentration, of enzymatic activity of GST, catalase, lipid peroxidation and genotoxities. In the acute toxicity test, the low value of LC50;96h (1.81 mg.L- 1), suggests that this species of fish, in this phase of development, it presents the great sensitivity to the KMnO4. In the cronic toxicity test, the fishes exposed in the concentrations of 1 mg.L-1 de KMnO4 did not present significant variations in the analyzed sanguineous parameters when compared with the control group. In concentration of 4 mg.L-1 the hematological alterations indicated process of hemolysis and immunosuppression in consequence of the oxidant action of KMnO4. In the immunologicals analysis, the concentrations of 1 and 4 mg.L-1 KMnO4 had significant reduction of the fagocitic capacity of the fishes suggesting suppression of the immune system. In the analysis biochemical, only the enzyme GSH presented significant increase... (Complete abstract click electronic access below)

Pharmaceuticals are an important class of pollutants in aquatic ecosystems. Detected concentration are typically in the range 1 ng/L – 1 μg/L. Traditional wastewater treatment does not provide a complete removal of these contaminants; hence, they may have a negative impact on the environment. In addition, microalgae are an ecologically-meaningful target group of species for bioindication purposes as well as primary production and oxygen supply. The present work aimed to investigate the effect of Ibuprofen on the green alga Pseudokirchneriella subcapitata. Algal cultures were exposed to five different concentrations of the drug (5, 15, 45, 135, 405 mg/L) for four days. Absorbance measured at 680 nm was determined every day and obtained data were transformed into cell concentration (cells/mL) by a previously prepared calibration curve. Specific growth rate, generation time, percent inhibition and effective concentration were calculated. Moreover, one way ANOVA with Tukey’s test were applied to observe differences between groups and time periods. Based on this study, all the cultures treated with Ibuprofen had a growth inhibition as well as presenting a lag phase. Increasing the Non-Steroidal Anti-Inflammatory drug (NSAID) concentration reduced the growth rate and consequently, increased the percent inhibition in a concentration-dependent manner. According to this report, new research should be focused on the development of hybrid systems for degradation and removal of pharmaceuticals. NSAID pollution may lead to a reduction in the diversity and number of functional groups of eukaryotic algae. Finally, more research should be devoted to the toxicity of drugs in a variety of test organisms and development of reliable methods for toxicity test at low and chronic exposures to achieve more realistic conclusions.

Foram realizados testes de toxicidade ao longo de dois anos, com amostras de água e sedimento do rio Corumbataí, entre Novembro de 2004 e Setembro de 2006, com o objetivo de avaliar a qualidade da água e do sedimento. Os testes de toxicidade aguda realizados com os organismos Chironomus xanthus, Daphnia magna, Hydra attenuata, Lactuca sativa e Pseudokirchneriella subcapitata indicaram variados graus de toxicidade nos diferentes pontos de coleta do rio Corumbataí, com maior ocorrência de toxicidade nos pontos de coleta mais próximos à foz do rio, principalmente devido à afluência do Ribeirão Claro. Todas as amostras de sedimento se mostraram mais tóxicas do que as amostras de água dos mesmos locais, para todos os organismos utilizados, em todas as coletas realizadas. Para todos os organismos, foram realizados testes de sensibilidade, com substância de referência (NaCl), mensalmente, a fim de garantir a qualidade dos cultivos em laboratório e dos bioensaios realizados, com resultados regulares e satisfatórios. Os efeitos produzidos pelas amostras ambientais sobre as sementes de alface (Lactuca sativa) foram bastante variáveis e irregulares, não possibilitando os cálculos de CI50. Decidiu-se por bem suspender a realização deste teste após um ano. Dentre todos os endpoints avaliados, os dos testes de Hydra attenuata e Pseudokirchneriella subcapitata se mostraram mais sensíveis, e o de Daphnia magna o menos sensível às amostras testadas. A avaliação da toxicidade através de efeitos subletais em H. attenuata se mostrou um bom parâmetro de avaliação das condições ambientais do rio Corumbataí, sendo um dos endpoints mais sensíveis utilizados. Outros testes de toxicidade foram realizados em algumas das oito coletas realizadas neste estudo, em caráter complementar: teste de toxicidade crônica com D. magna, teste de toxicidade LuminoTox, que utiliza sistemas enzimáticos vegetais, e o teste de genotoxicidade com Allium cepa, com o objetivo de avaliar suas sensibilidades e contribuições ao estudo. Estes bioensaios adicionaram informações a respeito dos níveis de poluição e toxicidade do rio Corumbataí, contribuindo com os bioensaios principais. Informações como parâmetros físicos e químicos, quantificação de elementos químicos e herbicidas ofereceram subsídios para a interpretação dos resultados obtidos com os testes de toxicidade. São apresentados também resultados das atividades referentes ao estágio de doutorado realizado no exterior (doutorado-sanduíche), no período de Setembro a Dezembro de 2007, na agência de proteção ambiental Environment Canada, no qual foi aplicado um teste de toxicidade com linhagens microbianas (MARA assay) em amostras de água e sedimento, juntamente com nanomateriais / Toxicity tests were conducted for two years with water and sediment samples from Corumbataí River, between November 2004 and September 2006, in order to assess the water and sediment quality. Acute toxicity tests conducted with Chironomus xanthus, Daphnia magna, Hydra attenuata, Lactuca sativa and Pseudokirchneriella subcapitata showed varying degrees of toxicity along the river course, with more toxic results in the sampling sites near the river mouth, due mainly to the inflow of Ribeirão Claro. All sediment samples were more toxic than the water samples (from the corresponding sites), for all test organisms, and for all samplings. Sensitivity tests were performed monthly, with NaCl as the reference toxicant, in order to guarantee both the laboratory culture quality and the bioassays conducted with these organisms. Results with NaCl were regular and satisfactory. The effects of the samples on lettuce seeds (L. sativa) were irregular, thus not allowing the estimative of IC50. It was decided to suspend the performance of this bioassay after one year of testing. Among all studied tests and endpoints, the tests with H. attenuata and P. subcapitata had the most sensitive endpoints, and the acute toxicity test with D. magna had the less sensitive one. Toxicity assessment of Corumbataí River based on Hydra sub-lethality endpoint was one of the most sensitive among the tested ones. Other bioassays were conducted at least once as part of this study, as a complementary assessment: the 21-day chronic toxicity test with D. magna, the LuminoTox bioassay, and the genotoxicity test with Allium cepa, in order to assess their sensitivity and contribution to the present study. These bioassays added information about the contamination levels and toxicity of Corumbataí River, contributing with the main bioassays performed. Data such as physical and chemical parameters, metals and herbicides determinations had a contribution to bioassay results interpretation. Results from a research project developed during a four-month stay (from September 2007 to December 2007) at Environment Canada Protection Agency are further described, regarding the application of the MARA bioassay, (conducted with 11 microbial strains), testing water and sediment samples, along with nanomaterials

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No. of bitstreams: 1 TeseASM.pdf: 6858970 bytes, checksum: 83be7f6c0d85cb91801e150418917482 (MD5) Previous issue date: 2016-03-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The aim of this study was to evaluate the effects of diuron and carbofuran, isolated and mixed, on Raphidocelis subcapitata, Paramecium caudatum and Ceriodaphnia silvestrii and carry out a preliminary risk assessment of these pesticides for Brazilian water bodies. For this, acute and chronic toxicity tests were performed with individual compounds and in combination, in its standard form and commercial formulations. The results showed that in individual action, these pesticides significantly inhibited the R. subcapitata population growth and caused physiological (chlorophyll a content) and morphological (complexity and cell size) changes in the cells. For this alga, the toxicity of standard active ingredients and their commercial formulations showed no significant differences. For the protozoan P. caudatum, acute toxicity tests evidenced an increase of mortality with increasing exposure time for the selected compounds. Moreover, these pesticides caused a significant decrease in population growth, number of generations and biomass of P. caudatum. The toxicity of standard diuron and its commercial formulation was similar for this protozoan, while commercial carbofuran was more toxic than its standard form, suggesting a synergistic interaction with “inert” ingredients. In contrast, for the cladoceran C. silvestrii, acute toxicity tests showed that diuron commercial product was 7.2 times more toxic than its standard active ingredient, whereas for carbofuran, commercial product was 1.5 times less toxic than its standard active ingredient. Regarding chronic toxicity of diuron herbicide, both standard and commercial form caused hormetic effects on fertility of C. silvestrii female. Carbofuran significantly reduced the reproduction of C. silvestrii at concentrations from 0.38 μg L-1 onwards. The tropical species C. silvestrii was more sensitive to these pesticides than cladocerans commonly used in temperate regions, and in addition, for carbofuran, this species was the most sensitive organism already tested (EC50-48h = 0,86 μg L-1). According to the toxicity tests results of diuron and carbofuran mixtures, acute and chronic exposures on all selected test organisms caused significant deviations from the toxicity predicted by Concentration Addition and Independent Action reference models. For P. subcapitata, data indicated the occurrence of synergism in the mixture of these compounds, especially when diuron is the dominant chemical in combination. For P. caudatum, dose ratio dependent deviation (synergism caused by carbofuran and antagonism caused by diuron) was observed in acute exposure and deviation for antagonism was verified for population growth at sublethal concentrations of the standard compounds mixtures. For C. silvestrii, antagonism was observed in low doses and synergism at high doses, predominating synergism in acute exposures of standard pesticides mixtures, while for reproduction the deviation for antagonism was found. The commercial product mixtures of diuron and carbofuran showed significantly different effects and more severe than the standard compounds mixtures for P. caudatum and C. silvestrii. Therefore, diuron and carbofuran mixture can interact and cause toxic responses different from those predicted for individual compounds. According to the concentrations found in water bodies in Brazil, these compounds can cause direct and indirect toxic effects on communities of algae, protozoa and cladocerans and may change the structure and functioning of aquatic ecosystems. In a preliminary risk assessment of these pesticides, risk quotients were larger than 1, indicating that diuron and carbofuran represent potential ecological risks to Brazilian water bodies. Given the above, it is concluded that the pesticides studied alone and in combination, caused toxicity to test organisms and represent potential ecological risk for aquatic environments, which suggests the implementation by the regulatory agencies of more stringent measures for the use of pesticides to improve the protection of aquatic biota. / O objetivo desta pesquisa foi avaliar os efeitos do diuron e do carbofuran, isolados e em mistura, sobre as espécies Raphidocelis subcapitata, Paramecium caudatum e Ceriodaphnia silvestrii e realizar uma avaliação de risco preliminar destes agrotóxicos para os corpos d’água brasileiros. Para isso, testes de toxicidade aguda e crônica foram realizados com os compostos isolados e em mistura, nas suas formas padrão e comercial. Os resultados mostraram que, em ação individual, estes agrotóxicos inibiram significativamente o crescimento populacional de R. subcapitata e causaram alterações fisiológicas (conteúdo de clorofila a) e morfológicas (complexidade e tamanho celular) nas células. Para esta espécie de alga, a toxicidade dos ingredientes ativos nas formas padrão e comercial não apresentaram diferenças significativas. Para o protozoário P. caudatum, os testes de toxicidade aguda evidenciaram um aumento da mortalidade com o aumento do tempo de exposição aos compostos selecionados. Além disso, estes agrotóxicos causaram uma diminuição significativa no crescimento populacional, no número de gerações e na biomassa de P. caudatum. A toxicidade do diuron padrão e de sua formulação comercial foi similar para este protozoário, enquanto que o carbofuran comercial foi mais tóxico do que a sua forma padrão, sugerindo a ocorrência de interações sinérgicas com os ingredientes “inertes”. Diferentemente, para o cladócero C. silvestrii, os testes de toxicidade aguda mostraram que o produto comercial de diuron foi 7,2 vezes mais tóxico do que o seu ingrediente ativo padrão, enquanto que para o carbofuran, o produto comercial foi 1,5 vezes menos tóxico do que o seu ingrediente ativo padrão. Em relação à toxicidade crônica, o herbicida diuron, tanto na forma padrão como comercial, causou efeitos horméticos sobre a fertilidade das fêmeas de C. silvestrii. Já o carbofuran reduziu significativamente a reprodução de C. silvestrii em concentrações a partir de 0,38 μg L-1. A espécie tropical C. silvestrii foi mais sensível a estes agrotóxicos do que cladóceros comumente utilizados em regiões temperadas, e além disso, para o carbofuran, esta espécie foi o organismo-teste mais sensível já registrado na literatura (CE50-48h = 0,86 μg L-1). De acordo com os resultados dos testes de toxicidade das misturas de diuron e carbofuran, exposições agudas e crônicas sobre todos os organismos-teste selecionados causaram desvios significativos da toxicidade prevista pelos modelos de referência de Adição de Concentração e Ação Independente. Para a alga R. subcapitata, os dados evidenciaram a ocorrência do sinergismo na mistura destes compostos, principalmente quando o diuron é o produto químico dominante na mistura. Para o P. caudatum, o desvio dependente da proporção da dose (sinergismo causado pelo carbofuran e antagonismo causado pelo diuron) foi observado em exposições agudas e desvio para o antagonismo foi verificado para o crescimento populacional em concentrações subletais das misturas dos compostos padrões. Para a C. silvestrii, observou-se o antagonismo em baixas doses e o sinergismo em altas doses, prevalecendo o sinergismo nas exposições agudas das misturas dos agrotóxicos padrões, enquanto que para a reprodução foi encontrado o desvio para o antagonismo. As misturas dos produtos comerciais de diuron e carbofuran apresentaram efeitos significativamente diferentes e mais graves do que as misturas dos compostos padrões para o P. caudatum e a C. silvestrii. Portanto, diuron e carbofuran em mistura podem interagir e causar respostas tóxicas diferentes das previstas para os compostos individuais. De acordo com as concentrações encontradas nos corpos d’água brasileiros, estes compostos podem causar efeitos tóxicos diretos e indiretos sobre as comunidades de algas, protozoários e cladóceros, podendo alterar a estrutura e o funcionamento dos ecossistemas aquáticos. Na avaliação de risco preliminar destes agrotóxicos, os quocientes de risco foram maiores do que 1, indicando que o diuron e o carbofuran representam riscos ecológicos potenciais para os corpos d’água brasileiros. Diante do exposto, conclui-se que os agrotóxicos estudados, isolados e em mistura, causaram toxicidade aos organismos avaliados e representam riscos ecológicos potenciais para os ambientes aquáticos, o que sugere a implantação pelas agências reguladoras de medidas mais restritivas para o uso destes agrotóxicos, visando uma melhor proteção da biota aquática.

Foram realizados testes de toxicidade ao longo de dois anos, com amostras de água e sedimento do rio Corumbataí, entre Novembro de 2004 e Setembro de 2006, com o objetivo de avaliar a qualidade da água e do sedimento. Os testes de toxicidade aguda realizados com os organismos Chironomus xanthus, Daphnia magna, Hydra attenuata, Lactuca sativa e Pseudokirchneriella subcapitata indicaram variados graus de toxicidade nos diferentes pontos de coleta do rio Corumbataí, com maior ocorrência de toxicidade nos pontos de coleta mais próximos à foz do rio, principalmente devido à afluência do Ribeirão Claro. Todas as amostras de sedimento se mostraram mais tóxicas do que as amostras de água dos mesmos locais, para todos os organismos utilizados, em todas as coletas realizadas. Para todos os organismos, foram realizados testes de sensibilidade, com substância de referência (NaCl), mensalmente, a fim de garantir a qualidade dos cultivos em laboratório e dos bioensaios realizados, com resultados regulares e satisfatórios. Os efeitos produzidos pelas amostras ambientais sobre as sementes de alface (Lactuca sativa) foram bastante variáveis e irregulares, não possibilitando os cálculos de CI50. Decidiu-se por bem suspender a realização deste teste após um ano. Dentre todos os endpoints avaliados, os dos testes de Hydra attenuata e Pseudokirchneriella subcapitata se mostraram mais sensíveis, e o de Daphnia magna o menos sensível às amostras testadas. A avaliação da toxicidade através de efeitos subletais em H. attenuata se mostrou um bom parâmetro de avaliação das condições ambientais do rio Corumbataí, sendo um dos endpoints mais sensíveis utilizados. Outros testes de toxicidade foram realizados em algumas das oito coletas realizadas neste estudo, em caráter complementar: teste de toxicidade crônica com D. magna, teste de toxicidade LuminoTox, que utiliza sistemas enzimáticos vegetais, e o teste de genotoxicidade com Allium cepa, com o objetivo de avaliar suas sensibilidades e contribuições ao estudo. Estes bioensaios adicionaram informações a respeito dos níveis de poluição e toxicidade do rio Corumbataí, contribuindo com os bioensaios principais. Informações como parâmetros físicos e químicos, quantificação de elementos químicos e herbicidas ofereceram subsídios para a interpretação dos resultados obtidos com os testes de toxicidade. São apresentados também resultados das atividades referentes ao estágio de doutorado realizado no exterior (doutorado-sanduíche), no período de Setembro a Dezembro de 2007, na agência de proteção ambiental Environment Canada, no qual foi aplicado um teste de toxicidade com linhagens microbianas (MARA assay) em amostras de água e sedimento, juntamente com nanomateriais / Toxicity tests were conducted for two years with water and sediment samples from Corumbataí River, between November 2004 and September 2006, in order to assess the water and sediment quality. Acute toxicity tests conducted with Chironomus xanthus, Daphnia magna, Hydra attenuata, Lactuca sativa and Pseudokirchneriella subcapitata showed varying degrees of toxicity along the river course, with more toxic results in the sampling sites near the river mouth, due mainly to the inflow of Ribeirão Claro. All sediment samples were more toxic than the water samples (from the corresponding sites), for all test organisms, and for all samplings. Sensitivity tests were performed monthly, with NaCl as the reference toxicant, in order to guarantee both the laboratory culture quality and the bioassays conducted with these organisms. Results with NaCl were regular and satisfactory. The effects of the samples on lettuce seeds (L. sativa) were irregular, thus not allowing the estimative of IC50. It was decided to suspend the performance of this bioassay after one year of testing. Among all studied tests and endpoints, the tests with H. attenuata and P. subcapitata had the most sensitive endpoints, and the acute toxicity test with D. magna had the less sensitive one. Toxicity assessment of Corumbataí River based on Hydra sub-lethality endpoint was one of the most sensitive among the tested ones. Other bioassays were conducted at least once as part of this study, as a complementary assessment: the 21-day chronic toxicity test with D. magna, the LuminoTox bioassay, and the genotoxicity test with Allium cepa, in order to assess their sensitivity and contribution to the present study. These bioassays added information about the contamination levels and toxicity of Corumbataí River, contributing with the main bioassays performed. Data such as physical and chemical parameters, metals and herbicides determinations had a contribution to bioassay results interpretation. Results from a research project developed during a four-month stay (from September 2007 to December 2007) at Environment Canada Protection Agency are further described, regarding the application of the MARA bioassay, (conducted with 11 microbial strains), testing water and sediment samples, along with nanomaterials

Advanced oxidation technology (AOT) has been used to destroy microorganisms in ballast water by breaking down the cell membranes. The primary objective of this study was to determine the effects of a ballast water treatment system that uses a combination of UV-C (λ=254 nm), Vacuum-UV (VUV; λ=185 nm) and photocatalytic titanium dioxide (TiO2) on a freshwater algae, Pseudokirchneriella subcapitata, and a marine algae, Tetraselmis suecica. The coupling of a semiconductor, such as TiO2, with a UV source is known as an advanced oxidative technology (AOT). To test the effects of TiO2 and wave length on algae, dose-response experiments were conducted to determine the species median lethal dose (LC50) for each of the following treatments: UV-light emitted at 254 nm (UVλ=254 nm), UV-light emitted at 254 nm in the presence of TiO2 (AOTλ=254 nm), and UV-light emitted at λ=254 nm (90 %) and 185 nm (90 %) in the presence of TiO2 (AOTλ=185 + 254 nm). In both species, TiO2 significantly increased mortality, most likely due to the biologically harmful radicals generated at the TiO2 surface. The addition of the 185 nm wavelength significantly increased cell mortality in P. subcapitata, but not in T. suecica. Across all three treatments, P. subcapitata was more sensitive than T. suecica. The secondary purpose of this study was to assess the applicability of ImageJ, an image analysis software, for highthroughput data to analyze the effectiveness of ballast water treatment. ImageJ has been used to rapidly and accurately perform cell Live/Dead analysis; however, several hurdles were identified.

Made available in DSpace on 2016-06-02T19:31:43Z (GMT). No. of bitstreams: 1 2512.pdf: 462139 bytes, checksum: b566d530cb4e59c327e6ea0ee9a9cda6 (MD5) Previous issue date: 2009-06-10 / Universidade Federal de Minas Gerais / With the advance of industrialization, there was an increase in the quantity of substances discharged in nature without treatment. Many of these substances are toxic and can cause adverse effects to aquatic biota, and may affect the rest of the food chain, including humans. For better understanding of the effects of contamination, there is a growing progress in the study of exposure of organisms of different trophic levels of the contaminant and monitoring changes in their development and reproduction. Copper, an essential element at low concentrations, can cause adverse effects in higher concentrations. The aim of this study was to evaluate changes in a zooplankton species, Daphnia laevis (Crustacea, Cladocera) fed with algae (Pseudokirchneriella subcapitata) previously exposed to different concentrations of copper. The accumulation of metal was measured both in algae and in cladoceran. The animals were monitored throughout its life cycle through the testing of chronic toxicity and through bionomic parameters and calculation of their secondary production, the treatments were compared to a control. The results suggest that exposure to contaminated food directly influence the reproduction of animals, and found significant statistical differences (p <0.05) in the total number of eggs and neonates produced over the life of the animal. Another parameter that was affected significantly was the secondary production of animals, where changes were observed mainly in the investment to reproduction, affecting the total secondary production. Through the results, consider the importance of the capture of copper through the food and how the secondary production, although very important, is not explored in ecotoxicological studies. / Com o avanço da industrialização, houve um aumento na quantidade de substâncias despejadas sem tratamento na natureza. Muitas destas substâncias são tóxicas e podem causar efeitos adversos à biota aquática, podendo atingir o resto da cadeia trófica, incluindo o homem. Para a melhor compreensão dos efeitos da contaminação, há um crescente avanço no estudo da exposição de organismos de diferentes níveis tróficos ao contaminante e o acompanhamento de mudanças no seu desenvolvimento e reprodução. O cobre, elemento essencial em baixas concentrações, pode causar efeitos negativos em concentrações mais elevadas. O objetivo do presente estudo foi avaliar as mudanças ocorridas em uma espécie zooplanctônica, Daphnia laevis (Crustacea, Cladocera), alimentada com algas (Pseudokirchneriella subcapitata) previamente expostas a diferentes concentrações de cobre. O acúmulo de metal foi quantificado tanto na alga quanto no cladócero. Os animais foram acompanhados durante todo o seu ciclo de vida através da realização de testes de toxicidade crônica e, através de parâmetros bionômicos e cálculo de sua produção secundária, os tratamentos foram comparados a um controle. Os resultados encontrados sugerem que a exposição ao alimento contaminado influenciou diretamente na reprodução dos animais, sendo encontradas diferenças estatísticas significantes (p<0,05) no número total de ovos e de neonatos produzidos ao longo da vida do animal. Outro parâmetro que foi afetado significantemente foi a produção secundária dos animais, onde foram observadas mudanças principalmente no investimento destinado à reprodução, afetando a produção secundária total. Através dos resultados obtidos, consideramos a importância da captura do cobre através do alimento e de como a produção secundária, embora muito importante, é pouco explorada nos trabalhos ecotoxicológicos.

L’eutrophisation et la contamination des sédiments (ex : métaux, nutriments, etc.) sont des problèmes majeurs pour la protection des écosystèmes aquatiques et la protection des ressources d’eau douce. Le lac Saint-Augustin (Québec, Canada) est aux prises avec ces deux problèmes. Depuis 2001, plusieurs épisodes de fleurs d’eau de cyanobactéries sont rapportés durant la saison estivale (P &gt; 70 µg/L). Galvez et collaborateurs ont proposé une méthode de restauration pour ce lac consistant : (I) à réduire la teneur en phosphore de l’eau du lac par coagulation/floculation avec du sulfate d’aluminium et (II) à effectuer un recouvrement actif de roche calcaire et de sable afin d’isoler le floc d’Al, le P et les autres contaminants (ex., métaux) et permettre la recolonisation par le benthos. L’objectif des présents travaux était d’évaluer l’écocompatibilité de cette méthode. Deux approches écotoxicologiques ont été employées : (I) essais de toxicité monospécifiques (croissance de l’algue Pseudokirchneriella subcapitata et de la lentille d’eau Lemna minor; survie et reproduction de la daphnie Daphnia magna et de l’amphipode Hyalella azteca, survie, croissance et émergence de l’invertébré Chironomus riparius ainsi que survie des larves de tête-de-boule Pimephales promelas et des alevins de truites arc-en-ciel Oncorhynchus mykiss) et (II) essai en microcosmes de 2 litres tel qu’adapté par Triffault-Bouchet. La toxicité de l’aluminium et l’impact de la roche calcaire ont été étudiés séparément : d’abord avec eau et sédiments artificiels et ensuite avec eau et sédiments du lac Saint-Augustin. Les résultats démontrent que les algues et les daphnies sont affectées par l’application d’alun. Aucun effet n’a été observé chez les autres organismes. Ceux-ci ont eu la capacité de recoloniser les milieux traités avec l’alun ou avec la technique complète. Ces résultats tendent à démontrer que la méthode de restauration est prometteuse. L’écocompatibilité de la technique ne pourra cependant être démontrée que par des essais in situ et après un suivi étroit du phytoplancton et du zooplancton dans le lac. Toutefois, dans le cadre des présents travaux, l’efficacité des traitements (en terme de déphosphatation) n’a pas permis d’atteindre le critère de qualité du MDDEP (20 µg/L). Ces paramètres devront être étroitement suivis lors des essais in situ. Mots clés : Eutrophisation, sédiments contaminés, restauration de lac, aluminium, recouvrement actif, évaluation écotoxicologique, bioessais monospécifique, microcosmes. / Eutrophication and contaminated sediments (e.g.: nutrients, metals, etc.) are preoccupying issues in aquatic ecosystems and water resource protection. Saint-Augustin Lake (Quebec, Canada) is affected by both problems in addition to the presence of de-icing salts. This small shallow lake has low renewal time and receives an intensive phosphorus transfer from bottom sediments to the water column. Since 2001, the lake presents cyanobacteria blooms every summer (P &gt; 70 μg/L). Galvez and collaborators has proposed a remediation method for this lake that consists of (i) the precipitation of phosphorus present in the water column by the addition of alum, in association with the deposition of (ii) an active capping layer (limestone + sand) to isolated P, Al and other contaminants (e.g., metals) within bottom sediments and allow recolonisation by benthos. The objective of this study is to assess the ecotoxicological impact of that remediation method. Two ecotoxicological approaches are used to assess the impact of this method: (I) single-species bioassays (algae Pseudokirchneriella subcapitata and duckweed Lemna minor growth; daphnid Daphnia magna and amphipod Hyalella azteca survival and reproduction, invertebrate Chironomes riparius survival, growth and emergence, fathead minnow P. promelas and rainbow trouts O. mykiss survival) and (II) a 2-L microcosm as adapted by Triffault-Bouchet. Alum toxicity and limestone impact were studied separately in laboratory: first with artificial water and sediments and then using actual lake overlying water and sediments. The results show that algae and daphnids are sensitive to alum treatment. No significant effects were observed on the other organisms. These organisms had the ability to recolonize the treated media either with alum treatment or with complete treatment. These results suggest that the restoration method is promising. The environmental compatibility of the technique, would be demonstrated after testing in situ with a close monitoring of phytoplankton and zooplankton in the lake. However, the results of this study showed that the treatments dephosphatation efficacity was not enought to reach the MDDEP quality criteria (20 µg/L). Also, the concentration of residual aluminum after treatments was still over the MDDEP quality criteria after treatments. Keywords : Eutrophication, contaminated sédiments, lake restauration, aluminum, active capping, écotoxicological évaluation, monospécific bioessais, microcosms.