Intrinsic to the many nano-enabled products are atomic-size multifunctional engineered nanomaterials, which upon release contaminate the environments, raising considerable health and safety concerns. This Ph.D. dissertation is designed to investigate (i) whether metals or oxide nanoparticles are more toxic than ions, and if MetPLATETM bioassay is applicable as a rapid nanotoxicity screening tool; (ii) how variable water chemistry (dissolved organic carbon (DOC), pH, and hardness) and organic compounds (cysteine, humic acid, and trolox) modulate colloidal stability, ion release, and aquatic toxicity of silver nanoparticles (AgNP); and (iii) the developmental responses of crop plants exposed to Ag- or ZnO- (zinc oxide) nanoparticles. Results suggest that the MetPLATEcan be considered a high-throughput screening tool for rapid nanotoxicity evaluation. Detectable changes in the colloidal diameter, surface charge, and plasmonic resonance revealed modulating effects of variable water chemistry and organic ligands on the particle stability, dissolution, and toxicity of AgNPs against Escherichia coli or Daphnia magna. Silver dissolution increased as a function of DOC concentrations but decreased with increasing hardness, pH, cysteine, or trolox levels. Notably, the dissociated Ag+ was inadequate to explain AgNP toxicity, and that the combined effect of AgNPs and dissolved Ag+ under each ligand treatment was lower than of AgNO3. Significant attenuation by trolox signifies an oxidative stress-mediated AgNP toxicity; its inability to attenuate AgNO3 toxicity, however, negates oxidative stress as Ag+ toxicity mechanism, and that cysteine could effectively quench free Ag+ to alleviate AgNO3 toxicity in D. magna. Surprisingly, DOC-AgNPs complex that apparently formed at higher DOC levels might have led daphnids filter-feed on aggregates, potentially elevating internal dose, and thus higher mortality. Maize root anatomy showed differential alterations upon exposure to AgNPs, ZnONPs, or their ions. Overall, various metal-based nanoparticles revealed lower toxicity than their ions against multiple organisms. This study showed that particle size, surface properties, and ion release kinetics of AgNPs modify following release into aquatic environment, suggesting potential implications to ecosystem health and functions, and that caution be applied when extending one species toxicity results to another because obvious differences in organism biology—supporting species sensitivity paradigm—can significantly alter nanoparticle or ionic toxicity.

Dans le contexte du développement exponentiel des nanotechnologies, les nanomatériaux sont susceptibles de se disséminer dans l'environnement. Les végétaux sont un élément sensible des écosystèmes car ils constituent une interface entre l'eau, le sol et l'air et se situent à la base de la chaine trophique. Cette étude avait pour but d'évaluer l'impact des nanoparticules de TiO2 et des nanotubes de carbone sur les végétaux, et plus particulièrement sur le blé et le colza. L'accent a également était mis sur la caractérisation des nanomatériaux employés. Nous avons mis en évidence l'accumulation racinaire et le transfert vers les feuilles des nanoparticules de TiO2 et des NTC dans le blé et le colza après une exposition en hydroponie. Les nanoparticules de TiO2 sont également accumulées dans les plantes lors d'une exposition racinaire sur sol ou encore lors d'une exposition par voie aérienne. Les nanoparticules de TiO2 s'accumulent dans les végétaux à hauteur de quelques dizaines voire centaines de mg Ti/kg MS, leur phase cristalline n'est pas modifiée et ces nanoparticules ne se dissolvent pas lors de leur transfert dans le végétal. Les NTC s'accumulent en plus faible quantité (centaines de µg NTC/kg MS) et il semble qu'ils soient altérés par le contact avec le végétal. Ces nanomatériaux affectent peu le développement des végétaux. Sur huit tests réalisés, seule l'élongation racinaire s'est révélée être un critère sensible, avec une induction de l'élongation pour les NPs et les NTC présentant le plus faible diamètre nominal. Enfin, une nette influence du diamètre nominal des nanomatériaux a pu être mise en évidence, contrôlant ainsi leur internalisation, leur transfert et leurs effets biologiques sur les végétaux. / The field of the nanotechnology exponentially increased during the last ten years. Intensive production of nanomaterials would lead to their release in the environment. Plants are one of the most sensitive organisms since they are at the interface between soil, water and air. Moreover, they represent a point of entry into the food chain. This study deals with the impact of TiO2 nanoparticle and carbon nanotube on plants, specifically on wheat and rapeseed. The physico-chemistry of nanomaterials has been deeply characterized.We prove that TiO2 nanoparticles and carbon nanotubes are internalized in roots and transferred to shoot of both wheat and rapeseed upon hydroponics exposure. TiO2 nanoparticles can also be internalized upon exposure in soil and even after an aerial contamination. TiO2 nanoparticles are accumulated in plants up to few hundred mg Ti/kg DM, their crystal phase is not modified and they do not dissolve during their transfer inside plants. CNT are less accumulated, up to few hundred µg NTC/kg DM, and seem to be altered by their transfer to and though plants.The nanomaterials we studied have very limited impact on plant development and physiology. One test out of eight has shown modulation after nanomaterial exposure: root elongation was induced when exposed to very small of both nanomaterials. Finally, we show that the nominal diameter of nanomaterials is negatively correlated with their internalization, transfer to shoot and induction of root elongation: the finest the nanomaterial, the highest their accumulation and impact on plant development.

Les assemblages d'espèces colonisatrices des déjections constituent des systèmes d'étude intéressants de par la nature de la ressource exploitée et de par le rôle qu'ils exercent dans les écosystèmes pâturés. Une grande diversité d'espèces d'insectes, principalement des diptères et des coléoptères, colonisent les bouses et contribuent à leur disparition, permettant un apport en nutriments au pâturage. Comprendre le lien entre ces différentes espèces et les fonctions écologiques réalisées représente donc un enjeu afin de préserver ce système et d'en assurer son bon fonctionnement. Certaines molécules administrées comme endectocides au bétail, comme l'ivermectine, impactent la structure de la communauté coprophile par leurs effets toxiques sur certains groupes comme les Sepsidae. Bien que leurs effets se soient montrés significatifs sur l'émergence des insectes coprophiles, la disparition des bouses ne s'en est pas trouvée affectée. Il convient alors de rester prudent sur les effets à long terme de ce type de molécules, même si à court terme les effets ne paraissent pas pertinents. La première semaine est essentielle à la bonne dégradation des bouses par l'action d'une première vague de colonisation par les insectes coprophages, tandis qu'en seconde semaine la colonisation par les prédateurs en réduit la vitesse. L'ensemble de la communauté coprophile ne permet donc pas d'accélérer le processus de recyclage des bouses. Une augmentation des effectifs de bousiers accélère la disparition des bouses et indirectement favorise la minéralisation de la litière dans le sol. Toutes les espèces ne contribuent pas équitablement au fonctionnement du système. Les plus gros fouisseurs enterrent des quantités plus importantes de matière fécale, facilitant ainsi les échanges de nutriments entre le sol et la déjection. D'importantes pistes restent à développer concernant les facteurs influençant la colonisation et les interactions entre les organismes afin de pouvoir utiliser les bousiers comme bioindicateurs pour en mesurer les services rendus. / Assemblages of species colonizing droppings constitute interesting systems for study due to the nature of the resource they exploit and the role they exert in the grazed ecosystems. A wide diversity of insects, mainly flies and beetles, colonize dung pats and contribute to their disappearance allowing a contribution in nutrients to the pasture. Understanding the relationship between these species and the ecological functions they perform represents therefore a stake to maintain this system and ensure its proper functioning. Some molecules administered as endectocides to livestock, such as ivermectin, impact the coprophile community structure by their toxic effects on certain taxonomic groups such as Sepsidae. Although their effects are significant on the emergence of coprophilous insects, dung disappearance was not affected. It is then advisable to remain careful on the long-term effects of this type of chemicals, even if the short-term effects are not relevant. The first week of colonization by the wave of coprophagous insects appear essential for complete dung degradation while the second week of colonization by predators reduced the speed of degradation. Therefore the whole coprophilous community does not accelerate the process of recycling dung. An increase of the numbers of dung beetles accelerates the disappearance of dung pats and the loss of litter in the soil. However, all species do not contribute in the same manner to the functioning of the system. The largest tunnelers bury larger amounts of fecal matter and thus they facilitate exchange of nutrients between soil and dung. Important trails remain to be developed concerning the factors influencing colonization and the interactions between organisms before to be able to use dung beetles as bioindicators and to measure their services.

Endocrine disruptors are natural or manmade substances which affect hormonal systems of organisms. Biologically relevant concentrations are commonly being detected in the environment. The effluents of wastewater treatment plant present their significant secondary source. Due to their occurence and quantity the interest in mixtures increases. Ecotoxicological assays with genetically modified Saccharomyces cerevisiae were aplied to verify reliability of predictive mathematical models for mixtures of standards (estrone, 17β-estradiol, 17α-ethinylestradiol, estriol, bisphenol A, irgasan, 4-nonylphenol). Chromatographic analysis along with yeast assays were used for the evaluation of real samples of wastewater treatment plant effluents and sediments. Schindler's predictive model and Full logistic model (FLM) were more reliable for predicting the whole dose-response curve compared to Generalized concentration addition (GCA). Predicted values of a parameter EC50 from all three models were comparable to empirical measurements. Three out of four samples exhibited estrogenic activity 0.65 - 1.70 ng/L 17β-estradiol ekvivalent (EEQ) above the limit of detection 0.13 - 0.33 ng/L EEQ. Antiestrogenic activity was detected in one of the samples. Prediction could be carried out only in the case of the sediments...

Os corantes são utilizados pelo homem há mais de 20 mil anos, com emprego nas indústrias têxteis, farmacêuticas, alimentícias, cosméticas, fotográficas, entre outras. Contudo, apesar de sua importância, os corantes podem ser tóxicos, mutagênicos e resistentes a muitos processos de degradação utilizados em estações de tratamento de águas residuais. Dentro deste contexto, o objetivo desta pesquisa foi avaliar os efeitos ecotoxicológicos dos corantes têxteis Disperse Red 60 (DR 60), Disperse Red 73 (DR 73) e Disperse Red 78 (DR 78) por meio de testes de toxicidade em três organismos de diferentes níveis tróficos: a bactéria Vibrio fischeri, o microcrustáceo Daphnia similis e o peixe Danio rerio (zebrafish), além da mutagenicidade na bactéria Salmonella typhimurium. Nossos resultados mostraram que os corantes DR 73 e DR 78 induzem toxicidade aguda em Vibrio fischeri e Daphnia similis, reduzindo a luminescência da bactéria e causando imobilidade no microcrustáceo, ao passo que o corante Disperse Red 60 não altera esses endpoints. No entanto, todos os corantes causam efeitos tóxicos em embriões e larvas de Danio rerio. O corante DR 60 ocasionou edemas oculares, alteração no comportamento e indução de efeitos pró-oxidantes em zebrafish. O corante DR 73 reduziu a inflação da bexiga natatória, induziu edemas do pericárdio, promoveu escoliose e alteração no saco vitelínico. Além disso, os corantes DR 73 e DR 78 alteraram o comportamento e balanço energético, induziram efeitos pró-oxidantes e neurotoxicidade. Quanto à mutagenicidade, o corante DR 73 induziu deslocamento do quadro de leitura e substituição de pares de base, enquanto o corante DR 78 causou apenas deslocamento do quadro de leitura e o corante DR 60 não induziu mutagenicidade. Em conclusão, os corantes Disperse Red 73 e Disperse Red 78 foram os mais tóxicos para os organismos avaliados, uma vez que alteraram maior número de endpoints, assim como causaram efeitos em menores concentrações, a partir de 1 ?g/L. Este estudo também demonstra a importância do uso de organismos testes de diferentes níveis tróficos, bem como a necessidade de uma maior atenção quanto ao registro e liberação para uso de corantes, visando prevenir danos ao ambiente e à saúde humana / Dyes have been used for more than twenty thousand years in the textile, pharmaceutical, food, cosmetic, and photographic industry, among others. Despite their importance in these applications, dyes can be toxic, mutagenic and resistant to many degradation processes used in wastewater treatment plants. In this context, the aim of this research was to evaluate the ecotoxicological effects of the Disperse Red 60 (DR 60), Disperse Red 73 (DR 73) and Disperse Red 78 (DR 78) textile dyes by means of toxicity tests on three organisms of different trophic levels: the bacterium Vibrio fischeri, the microcrustacean Daphnia similis and the fish Danio rerio (zebrafish). In addition, the mutagenicity of these dyes to the bacterium Salmonella typhimurium was evaluated. Our results demonstrate that the dyes DR 73 and DR 78 induce acute toxicity to V. fischeri (luminescence reduction) and D. similis (immobility), whereas the DR 60 did not alter these endpoints at the concentrations tested. However, all dyes caused toxic effects on embryos and larvae of D. rerio. DR 60 caused ocular edema, altered behavior and induced pro-oxidant effects in zebrafish. DR 73 reduced swim bladder inflation, induced pericardial edema, promoted scoliosis and changes in yolk sacs. In addition, DR 73 and DR 78 altered the zebrafish juvenile behavior and energy balance, and induced pro-oxidant effects and neurotoxicity. As for the mutagenicity test, DR 73 induced frameshift and base pair substitution, whereas DR 78 caused only frameshift and DR 60 did not induce any mutagenic effects. In conclusion, DR 73 and DR 78 were the most toxic for the organisms tested since they altered a greater number of endpoints and caused toxic effects at lower concentrations, i.e. from 1 ?g/L onwards. These results indicate the importance of using a battery of test organisms from different trophic levels when evaluating the environmental risks of dyes, as well as the need for greater attention regarding the Registration and authorization of the use of dyes in order to prevent unacceptable risks to the environment and human health.

O objetivo desta pesquisa foi estudar a degradação,pelo processo foto-Fenton, de um poluente-modelo (um antibiótico da classe dos nitrufuranos:a nitrofurantoína), utilizando-seLEDs-UV no lugar das lâmpadas tradicionalmente utilizadas, ou seja, das lâmpadas fluorescentes negras.Foram comparadas duas câmaras de irradiação, cada uma com um tipo de fonte, em termos de: porcentagem de remoção, ecotoxicidade (Lactuca sativa), atividade antimicrobiana (Escherichia coli), custos de capital (equipamentos), de operação (consumo energético) e das fontes luminosas, além do espaço ocupado. Os experimentos de degradação foramrealizados e otimizados via planejamento experimental, utilizando-se a Metodologia de Superfície de Resposta, obtendo-se as concentrações ótimas denitrofurantoína, de íons férricoe de peróxido de nitrogênio para cada caso.As câmaras estudadas apresentaram desempenhos semelhantes na remoção de nitrofurantoína (mais de 95% em 15 min), além de não ter havido a geração de produtos ecotóxicos (Lactuca sativa) e de ter sido alcançada a inativação biológica (Escherichia coli) do fármaco.A câmara de irradiação com LEDs é compacta, custa duas vezes menos que a outra e é quatro vezes mais eficiente em termos de consumo elétrico. A única desvantagem encontrada foi o custo dos LEDs-UV. Levando-se em conta o número de LEDs e de lâmpadas fluorescentes negras nas câmaras, o custo é trinta vezes maior. No entanto, o custo adicional dos LEDs-UV em relação às lâmpadas fluorescentes negras é facilmente compensado pela economia realizada nos custos de capital (aquisição do equipamento) e de operação (consumo energético).Em suma, pelo menos no caso da degradação da nitrofurantoína pelo processo foto-Fenton, os LEDs-UV mostraram-se substitutos vantajosos das lâmpadas fluorescentes negras, tradicionalmente utilizadas. / The goal of this research was to study the degradation, by the photo-Fenton process, of a model-pollutant (an antibiotic fromthe nitrofurans group: nitrofurantoin), using UV-LEDs instead of the lamps traditionally used, i.e. black fluorescent lamps. Two irradiation chambers were compared, each one of them with a type of light source, regarding: removal percentage, ecotoxicity (Lactuca sativa), antimicrobial activity (Escherichia coli), capital costs (equipment), operating costs (energy consumption), and light sources costs, as well as the space the chambers occupy.The degradation experiments were performed and optimized by experimental design, using the Response Surface Methodology, and obtaining the optimum concentrations of nitrofurantoin, ferric ions, and hydrogen peroxide, for each of the chambers. The studied chambers showed similar performances regarding nitrofurantoin removal (more than 95% in 15 min), besides the generation of no ecotoxic products (Lactuca sativa) and the biological inactivation (Escherichia coli) of the drug. The irradiation chamber with UV-LEDs is compact,cheaper (it is half of the price of the other one), and it is four times more efficient in terms of electric consumption. The sole disadvantage found was the cost of the UV-LEDs. Taking into consideration the number of LEDs and black fluorescent lamps used in the chambers, thiscost is 30 times greater. However, the additional cost of the UV-LEDsin comparison to black fluorescent lamps is easily compensated by the savings in capital costs (equipment acquisition) and operating costs (electric consumption). In summary, at least regarding the nitrofurantoin degradation by the photo-Fenton process, the UV-LEDs proved to beworthwhile alternatives for black fluorescent lamps, which are traditionally used.

Estudos recentes têm identificado a presença de diversos poluentes emergentes em ambientes aquáticos. A ocorrência em diferentes matrizes ambientais tem sido continuamente relatada, o que evidencia a necessidade de estudos de toxicidade. O DEET (N,N-dietil-meta-toluamida) é o princípio ativo mais utilizado em repelentes de insetos e está presente em diversas formulações comercialmente disponíveis. Além dos poluentes químicos, os organismos aquáticos estão sujeitos à exposição da radiação ionizante proveniente de fontes naturais ou em proximidades de instalações de usinas nucleares. O presente estudo avaliou a toxicidade do DEET em organismos irradiados e não irradiados com radiação gama de 60Co, e os efeitos que a radiação causa sob os lisossomos de hemócitos do mexilhão Perna perna. Para isso, foram realizados ensaios de toxicidade aguda para identificar a concentração de DEET e a dose de radiação gama passíveis de causar mortalidade, e posteriormente ensaios de citotoxicidade avaliando a estabilidade da membrana lisossômica em organismos expostos ao DEET e radiação ionizante. De acordo com os resultados obtidos nos ensaios de toxicidade aguda, a concentração de DEET que causa mortalidade em 50% dos organismos expostos (CL50) é de 114,27 mg L-1, e a dose de radiação que causa mortalidade (DL50) é de 1068 Gy. Nos os ensaios de citotoxicidade obteve-se a concentração de efeito não observado (CENO) para organismos irradiados e não irradiados de 0,0001 mg L-1 e a concentração de efeito observado (CEO) em concentrações acima desta. A CI25(72h) para organismos não irradiados foi de 0,0003 mg L-1 e a CI50(72h) foi de 0,0008 mg L-1 para organismos irradiados e não irradiados. Apesar das concentrações de efeito encontradas no presente estudo terem sido mais altas que as ambientais, estão na mesma ordem de grandeza e também deve-se levar em consideração os possíveis efeitos sinérgicos do DEET com outros contaminantes presentes em ambiente aquático. / Recent studies have identified the presence of several emerging pollutants in aquatic environments. The occurrence in different environmental matrices has been continuously reported, highlighting the need for toxicity studies. The DEET (N,N-diethyl-meta-toluamide) is the active ingredient used in most insect repellents, and is present in many commercially available formulations. Apart from chemical pollutants, aquatic organisms are subject to exposure of ionizing radiation from natural sources or in the vicinity of nuclear power plants. The present study evaluated the toxicity of DEET in organisms irradiated and non-irradiated with 60Co gamma radiation, and the effects that radiation causes in lysosomes of hemocytes of Perna perna mussel. For this purpose, assays were performed to identify the acute toxicity of DEET concentration and the dose of gamma radiation able to cause mortality. Subsequently, cytotoxicity assays were carried out to assess the stability of the lysosomal membrane in organisms exposed to ionizing radiation and DEET. According to the results obtained in acute toxicity tests, the concentration of DEET that causes mortality of 50% exposed organisms (LC50) is 114,27 mg L-1, and the radiation dose that causes mortality (LD50) is 1068 Gy. In the cytotoxicity assays, the concentration of the non-observed effect (NOEC) for irradiated and non-irradiated organisms 0.0001 mg L-1 and observed effect concentration (LOEC) at concentrations above this. The IC25 (72h) for non-irradiated organisms was 0.0003 mg L-1 and IC50 (72h) was 0.0008 mg L-1 for irradiated and non-irradiated organisms. Despite of the concentrations of effect found in this study were higher than in the environment, both measurements are in the same order of magnitude and should be also take into account the possible synergistic effects of DEET with other contaminants in the aquatic environment.

The effect of the soil organic status (SOS) on the dynamics and impact of a copper contamination was investigated in a coupled field and mesocosm study with a loamy vineyard soil that had been amended with conifer compost (CC) or not amended (NA) during a previous long-term field experiment. Soil mesocosms were contaminated at 240 mg Cu kg-1 and incubated for 24 months. Cu distribution and dynamics were assessed in the solid matrix at the microscale by size fractionation of soils and in the soil solution by measuring total and free exchangeable copper concentrations (Cu2+). Copper bioavailability, CuBio, was also measured with a whole-cell biosensor. The impact of copper on soil bacterial community was evaluated through the monitoring of the amount of copper-resistant bacteria and through the variations in bacterial community structure using ARISA (Automated-Ribosomal-Intergenic-Spacer-Analysis). Results showed that copper distribution, speciation and bioavailability are strongly different in the NA and CC soils, demonstrating that the organic status of soils largely controls the solid and liquid speciation of copper as well as its availability to microorganisms. Cu was shown to be dominantly distributed in the smallest size fractions (<20µm) of both control and amended soils and also in the coarser fraction (>250µm) of the CC soil. The coarser and finest size fractions of the soil are also the ones that release more Cu2+ and CuBio, explaining thus the important amount of Cu-resistant bacteria inhabiting these fractions and the differentiated temporal impact on the structure of soil bacterial community. The distribution of cultivable bacteria varied strongly between the two soils and was found to be well correlated with the distribution of added OM that controls thus bacterial community structure. The preferential impacts of copper observed in the smallest size fractions of the non amended soil demonstrate that copper toxicity and impact is also controlled by the reactivity of the soil fractions. This reactivity controls especially the release and the liquid speciation of Cu and thus bacteria-metal contact. A clear relationship between copper speciation, bioavailability, distribution and impact was established in the present study and will permit better predicting the fate and impact of metals in soils, by accounting for microscale control of metal impact / The effect of the soil organic status (SOS) on the dynamics and impact of a copper contamination was investigated in a coupled field and mesocosm study with a loamy vineyard soil that had been amended with conifer compost (CC) or not amended (NA) during a previous long-term field experiment. Soil mesocosms were contaminated at 240 mg Cu kg-1 and incubated for 24 months. Cu distribution and dynamics were assessed in the solid matrix at the microscale by size fractionation of soils and in the soil solution by measuring total and free exchangeable copper concentrations (Cu2+). Copper bioavailability, CuBio, was also measured with a whole-cell biosensor. The impact of copper on soil bacterial community was evaluated through the monitoring of the amount of copper-resistant bacteria and through the variations in bacterial community structure using ARISA (Automated-Ribosomal-Intergenic-Spacer-Analysis). Results showed that copper distribution, speciation and bioavailability are strongly different in the NA and CC soils, demonstrating that the organic status of soils largely controls the solid and liquid speciation of copper as well as its availability to microorganisms. Cu was shown to be dominantly distributed in the smallest size fractions (<20µm) of both control and amended soils and also in the coarser fraction (>250µm) of the CC soil. The coarser and finest size fractions of the soil are also the ones that release more Cu2+ and CuBio, explaining thus the important amount of Cu-resistant bacteria inhabiting these fractions and the differentiated temporal impact on the structure of soil bacterial community. The distribution of cultivable bacteria varied strongly between the two soils and was found to be well correlated with the distribution of added OM that controls thus bacterial community structure. The preferential impacts of copper observed in the smallest size fractions of the non amended soil demonstrate that copper toxicity and impact is also controlled by the reactivity of the soil fractions. This reactivity controls especially the release and the liquid speciation of Cu and thus bacteria-metal contact. A clear relationship between copper speciation, bioavailability, distribution and impact was established in the present study and will permit better predicting the fate and impact of metals in soils, by accounting for microscale control of metal impact

O impacto dos metais na fisiologia de peixes tem sido considerado preocupante, pois são contaminantes críticos nos ecossistemas aquáticos devido ao seu alto potencial de entrar no organismo, acumular-se e ser transferido na cadeia trófica e muitos estudos têm demonstrado os efeitos sobre várias funções em animais, quando expostos a estes metais. O rio Paraíba do Sul vem apresentando concentrações de alumínio (Al) e manganês (Mn) acima dos valores permitidos pela legislação Brasileira e, além disso, fatores abióticos tais como a acidez da água, podem contribuir para alteração do potencial de toxicidade, podendo acarretar em danos à biota aquática. As respostas desencadeadas pelos animais a estas mudanças ambientais podem levá-los a um estado de estresse, que é altamente energético devido à realocação de substratos inicialmente destinados às atividades de elevada demanda energética, como crescimento e reprodução, em direção às atividades que requerem intensificação para restaurar a homeostase. O presente estudo teve como objetivo avaliar os efeitos dos metais Al e Mn em pH ácido, isoladamente e em combinação, durante 96 horas (teste agudo) nas brânquias e nos substratos metabólicos de fêmeas vitelogênicas de Astyanax bimaculatus e, adicionalmente após um período de 96 horas em água limpa, verificar a habilidade dos animais em se recuperar na ausência destes metais. Os animais foram divididos em 5 grupos experimentais: CTR em pH neutro; pH ácido; Al; Mn; e Mn+Al. Os dados mostram que quando expostos a estes metais isoladamente, a atividade enzimática da bomba Na+/K+ ATPase e a quantidade de células de cloreto foram diminuídas, no entanto quando combinados, estes efeitos não foram observados. O Al isolado e em associação com o Mn promoveu peroxidação de fosfolipídios de membrana. Além disso nos animais expostos aos dois metais juntos, houve um aumento de ácidos graxos monoinsaturados (MUFA) e saturados (STA) acompanhado pela diminuição dos ácidos graxos polinsaturados (PUFA) o que pode ter evitado alterações na atividade de bomba e na quantidade de células de cloreto na combinação destes metais. Considerando-se os substratos metabólicos, a exposição ao Al diminuiu a concentração de proteínas nos ovários e no plasma, glicogênio muscular, além de alterar as porcentagens de MUFA e PUFA no fígado, e PUFA nos ovários. O Al também promoveu lipoperoxidação hepática, e no período de recuperação houve diminuição da concentração de lipídios em vários tecidos analisados. A exposição ao Mn promoveu diminuição das concentrações de proteínas totais em todos os tecidos analisados, seja no período de exposição agudo ou de recuperação, não havendo a recuperação deste substrato no fígado e nos ovários; o Mn promoveu lipoperoxidação nos fosfolipídios das membranas do fígado e, em associação com o Al, pareceu interferir na dinâmica dos PUFA das membranas dos ovários. Várias interações foram observadas entre o Al e Mn, demonstrando casos de antagonismo, potenciação e até mesmo de sinergismo entre estes metais, dependendo do parâmetro fisiológico analisado, evidenciando que a exposição de fêmeas vitelogênicas a estes metais pode ser prejudicial ao processo reprodutivo principalmente devido à ação observada, inclusive nos ovários / The impact of metals in fish physiology has been considered worrying due to their high potential of entering in the organism, to accumulate and be transferred through the food chain and many studies have shown the effects on several functions in animals, when exposed to these metals. The Paraíba do Sul river showed aluminum (Al) and manganese (Mn) concentrations above the values allowed by the Brazilian law and moreover abiotic factors, such as acidic water, can contribute to changing the toxicity potential and can result in damage to aquatic biota. The answers triggered by the animals to these environmental changes can lead to a stress state which has a high energetic cost due to the substrate reallocation, initially designated to activities with high energetic demand, as growth and reproduction, to activities that need to be intensified, to reestablish the homeostasis. The main goals of this study were to evaluate the effects of the metals Al and Mn in acidic pH, alone and in combination, during 96 hours (acute test) in the gills and in metabolic substrates in Astyanax bimaculatus vitelogenic females and, additionally, verify the ability of the animals to recover in the absence of the metals after the 96 hours in clear water. The animals were divided in 5 groups : CTR in neutral pH; acidic pH; Al; Mn; and Mn+Al. The results showed that when the animals were exposed to the isolate metals, there was a decrease in the Na+/K+ ATPase pump activity and in the amount of chloride cells, however when combined, these effects were not observed. Al, isolated or in association with Mn, promoted phospholipids peroxidation in gill membranes. Furthermore, in the animals exposed to both metals together, there were an increase in monounsaturated fatty acids (MUFA) and saturated fatty acids (STA) and decrease in polyunsaturated fatty acids (PUFA) which may have avoided alterations in pump activity and in the amount of chloride cells. In the metabolic substrates, Al exposition decreased plasma and ovaries protein concentration, muscle glycogen, and altered the percentage of MUFA and PUFA in the liver, and PUFA in the ovaries. Al also promoted liver lipoperoxidation, and in the recovery period lipid content decreased in most tissues analyzed. Mn exposition promoted a decrease in total protein content in all tissue analyzed, both in the acute and recovery periods, and there was no recovery of this substrate in liver and ovaries; Mn promoted lipoperoxidation in liver phospolipids and, in association with Al, interfered in the PUFA dynamic in ovaries membranes. Many interactions were observed between Al and Mn, evidencing antagonism, potentiation and also synergism, depending on the physiologic parameter analyzed, showing that the exposition of vitellogenic females to these metals can be harmful to reproductive process due to the observed actions, including in ovaries

Nas últimas décadas, a introdução de produtos de uso diário nos ambientes aquáticos tem sido uma das questões mais discutidas no que se refere ao monitoramento ambiental. Estes produtos não são totalmente removidos pelos processos convencionais de estações de tratamento de esgoto e de água e são continuamente inseridos no ambiente aquático. O Dietiltoluamida, um princípio ativo de repelente de insetos bastante utilizado mundialmente, é um composto ambientalmente persistente e sua toxicidade para alguns organismos aquáticos tem sido comprovada. Em substituição aos produtos sintéticos, a população tem optado em utilizar produtos naturais, sendo cada vez mais comum o uso de repelentes com óleos essenciais de gramíneas. O óleo essencial de capim-limão é um dos mais utilizados nas formulações de cosméticos e de cuidados pessoais. Entretanto, nenhum estudo tem comprovado a sua toxicidade para a biota aquática. Além dos poluentes químicos, os organismos aquáticos podem estar sujeitos à exposição da radiação ionizante proveniente de fontes naturais (background radiation) ou nas proximidades de instalações de usinas nucleares. O presente estudo avaliou a reprodução de invertebrados aquáticos C. silvestrii após a exposição à radiação gama e posteriormente submetidos aos princípios ativos de repelente sintético e natural. Para isso, avaliou-se a citotoxicidade in vitro bem como a ecotoxicidade aguda e crônica dos princípios ativos e o efeito da radiação gama para D. similis e C. silvestrii. Os ensaios com radiação gama foram realizados sob as mesmas condições dos testes de ecotoxicidade, utilizando o irradiador Gamma-Cell com fonte de Co60. De acordo com os resultados obtidos, o óleo essencial apresentou efeito citotóxico igual a 50 mg.L-1 enquanto para o dietiltoluamida, foi de 420 mg.L-1. O efeito tóxico agudo na sobrevivência (CE50) foi encontrado na concentração de 7,2 mg.L-1 e 3,8 mg.L-1 de óleo essencial para D. similis e C. silvestrii, respectivamente. Concentrações de 64,9 e 53,9 mg.L-1 de dietiltoluamida apresentaram efeito agudo na sobrevivência de D. similis e C. silvestrii, respectivamente. 3,4 mg.L-1 foi estabelecida como a concentração de inibição (CI25) de óleo essencial para o dietiltoluamida correspondeu a 16,4 mg.L- 1, ambos para C. silvestrii. As doses letais de radiação gama que causaram efeito agudo na sobrevivência (DL50) foram de 242 Gy para D. similis e 525 Gy para C. silvestrii. A reprodução de C. silvestrii apresentou redução de 25% na dose de 29 Gy. Depois de determinar a ecotoxicidade dos princípios ativos e o efeito da radiação gama, os organismos foram irradiados com dose de 25 Gy, sendo a maior dose que não causou efeito na reprodução de C. silvestrii, e posteriormente foram expostos às mesmas concentrações utilizadas para os princípios ativos. Os resultados mostraram que a reprodução de C. silvestrii não foi afetada significativamente após a irradiação dos organismos testados quando comparada com os organismos não irradiados. / Over the last decades, the introduction of personal care products in aquatic environments has been one of the most discussed issues regarding environmental monitoring. These products are not completely removed by conventional sewage and water treatment processes and are continuously inserted into the aquatic environment. Diethyltoluamide an active ingredient in insect repellents widely used worldwide is an environmentally persistent compound and its toxicity to some aquatic organisms has been proven. In order to replace synthetic products, people have opted to use natural products which made more common the use of repellents with essential oils of grasses. The essential oil of lemongrass is one of the most used in the formulations of cosmetics and personal care. However, no study has proven its toxicity to aquatic biota. In addition to chemical pollutants, aquatic organisms may be subject to exposure of ionizing radiation from natural sources (background radiation) or near nuclear installations. The present study evaluated the reproduction of aquatic invertebrates C. silvestrii after exposure to gamma radiation and further submitted to synthetic and natural repellents. On this account, we evaluated the in vitro cytotoxicity as well as acute and chronic ecotoxicity of the diethyltoluamide and lemongrass oil, as well as the effect of gamma radiation over D. similis and C. silvestrii. Irradiation experiments were carried out under the same conditions as performed for ecotoxicity assays, using a Gamma-Cell irradiator with a Co60 source. According to the results, the essential oil presented a cytotoxic effect at concentrations of 50 mg.L-1 whereas diethyltoluamide at 420 mg.L-1. The acute toxic effect on survival (EC50) was found at concentrations of 7.2 mg.L-1 for essential oil to and 3.8 mg.L-1 for D. similis and C. silvestrii respectively. Concentrations of 64.9 and 53.9 mg.L-1 of diethyltoluamide showed acute effect on survival of D. similis and C. silvestrii, respectively. 3.4 mg.L-1 of essential oil was established as the inhibition concentration (IC25) while for diethyltoluamide such value corresponded to 16.4 mg.L-1, both over C. silvestrii. The lethal doses induced by gamma radiation revealed an acute effect on survival (LD50) at 242 Gy for D. similis and 525 Gy for C. silvestrii. The reproduction C. silvestrii decreased by 25% at a dose of 29 Gy. After determining the ecotoxicity of the active ingredients and the effect of gamma irradiation, the organisms were irradiated at 25 Gy, which corresponded to the higher dose which caused no effect over the reproduction C. silvestrii and were subsequently exposed to the same concentrations used for the active ingredients. The results showed that reproduction C. silvestrii was not significantly affected after irradiation of the assayed organisms when compared to non-irradiated organisms.