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Ecossistemas estão sujeitos a diversos estressores, como o aumentoda temperatura em razão das mudanças climáticas e do lançamentode metais. O estresse térmico pode amplificar ou mascarar os efeitosdos metais nos organismos aquáticos. Este estudo teve como objetivorealizar uma revisão sistemática dos efeitos do aumento da temperatura,associado às mudanças climáticas, na toxicidade dos metais paraorganismos de água doce. Foram realizadas buscas em diferentes basesde dados eletrônicas, e a seleção dos artigos teve como critérios deinclusão: concordância com a questão da revisão sistemática, publicaçãoem inglês, espanhol e em português entre 1960 e 2020 e empregode metodologias padronizadas. Incluíram-se 43 artigos, que foramclassificados com relação ao ano e país de publicação, organismos-teste emetais estudados, temperaturas testadas e efeitos observados. Em 80%dos estudos analisados, o aumento da temperatura foi responsávelpor elevar a toxicidade dos metais para os organismos aquáticos.As temperaturas estudadas contemplam o aumento previsto peloPainel Intergovernamental de Mudanças Climáticas no fim do século21. O Brasil destaca-se entre os países com maior número de pesquisasnesta área, embora seja necessário o aumento dos estudos em regiõesde clima tropical. Com base na revisão bibliográfica, constatou-se que osmetais mais estudados foram o cobre e o cádmio, e os organismos-testemais utilizados nas pesquisas foram os peixes. As informações obtidascom estudos ecotoxicológicos são essenciais para a previsão dos efeitose a prevenção dos riscos associados à contaminação por metais dosecossistemas aquáticos mediante as mudanças climáticas. Ecosystems are subject to various stress factors, such as temperaturerises due to climate changes and metal disposal. Thermal stress canamplify or mask the effects of metals on aquatic organisms. This studyaims to carry out a systematic review on the effects of temperaturerises due to climate changes on the toxicity of metals for freshwaterorganisms. Searches were made in different electronic databasesand article selection was based on the following inclusion criteria:concordance with the question of a systematic review; publication inEnglish, Spanish, and Portuguese between 1960 and 2020; and the useof standard methodology. Forty-three articles were included, whichwere classified with respect to the year and country of publication,test-organisms and metals studied, temperatures tested, and theeffects observed. In 80% of the studies analyzed, a temperature risewas responsible for increasing the toxicity of metals for the aquaticorganisms. The temperatures studied contemplated the temperaturerise predicted by the Intergovernmental Panel for Climate Change atthe end of the 21st century. Brazil stood out among the countries forhaving the greatest number of research studies in this area, althoughthere is still the need for an increase in studies in tropical climateregions. Based on the literature review, it was shown that the metalsmost studied were copper and cadmium and the test-organisms mostused in the research projects were fish. The information obtainedfrom ecotoxicological studies is essential to predict the effects andprevent the risks associated with the metal contamination of aquaticecosystems due to climate changes.

Given the importance of metals in the contamination of aquatic ecosystems, studies are needed to assess the effects of these contaminants on aquatic organisms through different contamination pathways. Chromium (Cr) is a metal widely used in various industrial processes, considered a priority pollutant in several countries. In the present study, ecotoxicological tests were carried out with the microalga Chlorella vulgaris, evaluating the effects of Cr on cell density, pigment concentration, and biochemical composition. Additionally, the effects of chromium exposure on cladocerans (Ceriodaphnia dubia and Ceriodaphnia silvestrii) were investigated through three contamination routes: contaminated medium, contaminated food (C. vulgaris), and the combination of both situations (contaminated medium and food). The toxicity tests with cladocerans evaluated the metal effects on survival, number of newborn produced by female, and feeding activity. The results obtained demonstrated that 48 µg L-1 total dissolved Cr reduced cell density and increased protein, carbohydrate, and lipid content in C. vulgaris. The increase in the biochemical composition of microalgae upon exposure to Cr may have contributed to the non-observation of chronic toxic effects on daphnids in the treatment with contaminated food. A decrease of 31% and 26% in the number of C. silvestrii offspring was observed for the treatment with contaminated medium (35 µg L-1 total dissolved Cr) and associated treatment (35 µg L-1 total dissolved Cr and 3 × 10-14 g Cr cells-1), respectively. The importance of the Cr poisoning pathways and the difference in cladoceran species’ sensitivity to the metal were addressed.

Aulas práticas de ciências são importantes recursos metodológicos no processo ensino-aprendizagem dos alunos. No entanto, muitas escolas públicas brasileiras possuem escassa estrutura laboratorial, o que dificulta o desenvolvimento de atividades práticas. Este projeto de extensão teve como objetivo relatar o desenvolvimento de uma estratégia pedagógica interdisciplinar, abrangendo diversas áreas no ensino de Ciências, como conceitos de educação ambiental, citologia e óptica, por meio da construção e aplicação de um protótipo de microscópio, confeccionado com materiais eletroeletrônicos reutilizáveis, e outros de baixo custo. Participaram do projeto cento e vinte seis alunos, de escolas públicas do ensino fundamental. Foram ministradas oficinas compostas por: a) aula teórica e dinâmica abordando conceitos sobre a célula, física do microscópio e educação ambiental (resíduos sólidos e eletroeletrônicos, reciclagem e reutilização de resíduos, separação e responsabilização), b) aula prática com construção de protótipo de microscópio e c) questionário avaliativo. A atividade foi fundamentada nos Objetivos de Desenvolvimento Sustentável (ODS - ONU), visando à educação de qualidade e consumo e produção responsáveis, assim como na observação e experimentação como estratégia didática para a obtenção e assimilação de informações. Os resultados indicaram melhora na compreensão, por parte dos estudantes, de conceitos relacionados aos resíduos, células e funcionamento de um microscópio, confirmando a contribuição da atividade na melhoria do processo ensino–aprendizagem de ciências e conscientização ambiental. O protótipo, por ser de baixo custo e de fácil operação, pode aprimorar a infraestrutura de ensino das escolas, além de ser uma ferramenta interessante para auxiliar no ensino à distância.

Oral injuries in patients in Intensive Care Units (ICU) are recurrent, especially during endotracheal intubation, as the presence of the tube added to the teeth in the oral cavity can cause injuries to the tongue and other soft tissues. Ideally, tube stabilization devices should be easy to handle by the hospital staff, should always be available for use in ICUs, in addition to being low cost. The aim of this study was to develop a device for endotracheal tube stabilization and injury prevention in patients. 3D technical drawings were prepared, and the final version of the device was prototyped in polylactic acid and positioned in the patient. When compared to mouthguards described in the literature, it was found that the developed device provided stability for the tube, provided separation of the teeth from the adjacent soft tissues, and prevented the intubated patient from biting the tube, thus contributing to the prevention of traumatic injuries. It was concluded that the device has characteristics that allow stabilization of the endotracheal tube and the prevention of oral lesions in ICU patients, and can be used by hospital nursing staff.

Made available in DSpace on 2020-12-12T01:10:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Aquatic systems are seldom disturbed by a single stressor agent. Considering that nutrients and metals occur simultaneously in the environment, studies on the combined effects of these elements on the biota need to be carried out. The aim of this study was to evaluate the effect of the microalga Raphidocelis subcapitata exposed to different combinations of phosphorus (P) and zinc (Zn) on the neotropical cladoceran Ceriodaphnia silvestrii. The algae acclimated to P concentrations of 2.3 × 10−4 and 2.3 × 10−6 mol L−1 were exposed to concentrations of 0.10, 0.57, 1.13, and 2.27 × 10−6 mol Zn2+ L−1. The P acclimated algal cells showed different capacity to deal with external free Zn level, resulting in higher susceptibility to metal as P decreased in the test medium. Elevated cell metal values were observed in R. subcapitata acclimated to 2 × 10−6 mol P L−1 and exposed to Zn, as compared to the values found in the microalga exposed to 2 × 10−4 mol P L−1. A significant reduction in number of newborn produced by cladoceran was verified when the organism was fed alga containing 47 × 10−15 g Zn cell−1 (2 neonates per female) and 60 × 10−15 g Zn cell−1 (5 neonates per female). It was observed a decrease of 90% of C. silvestrii survival for the treatment with 47 × 10−15 and 60 × 10−15 g Zn cell−1. Algal cells acclimated to high and low concentrations of P were an important exposure route to Zn for C. silvestrii. Universidade Estadual Paulista (UNESP) Instituto de Ciência e Tecnologia Câmpus de São José dos Campos, Rodovia Presidente Dutra km 137,8, 12.247-004 NEEA/CRHEA/SHS Escola de Engenharia de São Carlos Universidade de São Paulo, Av. Trabalhador São Carlense, 400 Universidade Estadual Paulista (UNESP) Instituto de Ciência e Tecnologia Câmpus de São José dos Campos, Rodovia Presidente Dutra km 137,8, 12.247-004 FAPESP: 2015/19415-1 FAPESP: 2015/23951-6 FAPESP: 2016/22620-9

Made available in DSpace on 2018-11-26T15:27:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-09-01 Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Water samples were collected quarterly for 1 year from the newly created Osamu Utsumi uranium mine pit lake, Brazil, which is affected by acid mine drainage (AMD). The water presented mean pH values of 3.8, high mean electrical conductivity values (2391 A mu S/cm), manganese (74 mg/L), sulfate (1413 mg/L) and uranium (3 mg/L). The density of rotifera was significantly higher than that of cladoceran. Rotifera Keratella americana, K. cochlearis and the Cladocera Bosminopsis deitersi, Bosmina sp., are being reported for the first time in samples from a uranium pit lake with AMD. Of the species registered, the order Bdelloidea was the most important in terms of density (17,500-77,778 ind/m(3)), since it occurred throughout the whole sampling period. The combined effect of moderately acidic pH and other potential stress factors, such as high concentrations of stable and radioactive contaminants, probably influenced the zooplankton species composition in the pit lake. Brazilian Nucl Energy Commiss, Pocos de Caldas Lab, Radioecol Lab, BR-37701970 Pocos De Caldas, MG, Brazil Alfenas Fed Univ, Dept Biol, Limnol Lab, BR-37130000 Alfenas, MG, Brazil Univ Estadual Paulista, Dept Environm Engn, BR-12247004 Sao Jose Dos Campos, SP, Brazil Brazilian Nucl Energy Commiss, Pocos de Caldas Lab, Chem Anal Lab, BR-37701970 Pocos De Caldas, MG, Brazil Univ Estadual Paulista, Dept Environm Engn, BR-12247004 Sao Jose Dos Campos, SP, Brazil FAPEMIG: APQ-7807-5.04/07

Made available in DSpace on 2018-12-11T16:50:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 The water quality of the Antas reservoir, under the influence of treated effluents from a uranium mining area Ore Treatment Unit (UTM) with acid mine drainage, was investigated. Samples were collected every 3 months from the Antas reservoir (CAB, P41-E and P14) and from the UTM (P41-S). Chemical and acute 48 h toxicity tests using Ceriodaphnia silvestrii and Daphnia magna analyses were carried out to determine the potential environmental risks due to discharging the uranium mine effluents into this reservoir. All the water samples taken from the treated effluent (P41-S) were positively correlated with elevated concentrations of uranium, manganese, aluminum, zinc and fluoride and with high electrical conductivity and pH values, being considered toxic. In November 2014 water samples taken from the reservoir showed chemical concentrations above the legislation limits for fluoride (4.5 mg L-1) uranium (0.082 mg L-1), sulfate (662.4 mg L-1), manganese (1.125 mg L-1) and aluminum (1.55 mg L-1), and in July 2015 for fluoride (2.55 mg L-1), uranium (0.01 mg L-1) and manganese (0.36 mg L-1). The extremely high average value for hardness (543.55 mg L-1) possibly reduced the toxicity potential of this chemical species mixture with respect to the bioindicators. The influence of the variation in water hardness on the toxicity of the cladocerans was discussed. Radioecology Laboratory Poços de Caldas Laboratory Brazilian Nuclear Energy Commission, Rodovia Poços de Caldas/Andradas km 13 São Paulo State University (UNESP) Institute of Science and Technology São José Dos Campos Rodovia Presidente Dutra, Km 137, 8 Eugenio de Melo Community Ecology Laboratory University of Vale Do Itajaí, Rua Uruguay, 458 Chemical Analyses Laboratory Poços de Caldas Laboratory Brazilian Nuclear Energy Commission, Rodovia Poços de Caldas/Andradas km 13 São Paulo State University (UNESP) Institute of Science and Technology São José Dos Campos Rodovia Presidente Dutra, Km 137, 8 Eugenio de Melo

The quality of the water in a uranium-ore-mining area located in Caldas (Minas Gerais State, Brazil) and in a reservoir (Antas reservoir) that receives the neutralized acid solution leaching from the waste heaps generated by uranium mining was investigated. The samples were collected during four periods (October 2008, January, April and July 2009) from six sampling stations. Physical and chemical analyses were performed on the water samples, and the data obtained were compared with those of the Brazilian Environmental Standards and WHO standard. The water samples obtained from waste rock piles showed high uranium concentrations (5.62 mg L(-1)), high manganese values (75 mg L(-1)) and low average pH values (3.4). The evaluation of the water quality at the point considered the limit between the Ore Treatment Unit of the Brazilian Nuclear Industries and the environment (Consulta Creek) indicated contamination by fluoride, manganese, uranium and zinc. The Antas reservoir showed seasonal variations in water quality, with mean concentrations for fluoride (0.50 mg L(-1)), sulfate (16 mg L(-1)) and hardness (20 mg L(-1)) which were low in January, evidencing the effect of rainwater flowing into the system. The concentrations for fluoride, sulfate and manganese were close or above to the limits established by current legislation at the point where the treated mining effluent was discharged and downstream from this point. This study demonstrated that the effluent discharged by the UTM affected the quality of the water in the Antas reservoir, and thus the treatments currently used for effluent need to be reviewed.

In this study, we investigated the microbial community (bacteria and protozooplankton) of a Brazilian reservoir that receives neutralized acid mine drainage flowing from piles of earth produced during uranium extraction. Thus, this research represents an attempt to fill a gap in the information on the ecology of freshwater microorganisms in tropical oligotrophic habitats, in particular in systems affected by high levels of the uranium. During the study, we observed very low chlorophyll a contents and protozooplankton cell densities and biomass. These cell densities were between 0 and 89 cells L −1 and were lower than those frequently reported for oligotrophic freshwater lakes. In contrast, bacterial densities were normal or even slightly high, between 1.85 to 6.0 × 10 9 cells L −1 . The present study has demonstrated very low protozooplankton cell densities and biomass in oligotrophic reservoir under the influence of acidic mining effuents and of high levels of ionizing radiation. It is likely that the ciliate cell densities and biomasses recorded in this study, which fall significantly below the previously published values, can be explained by the chronic fractionated exposure of these protozoa to the high levels of uranium to this system.

The present study was carried out in a uranium ore mining area located in Caldas, in the southern region of the state of Minas Gerais, Brazil. The present study was undertaken to evaluate the ecologies of populations of the bioleaching microorganisms (Acidithiobacillus ferrooxidans and A. thiooxidans) in effluents from mining companies containing sulfides and associated radionuclides, and to assess the physico-chemical and radiological uranium mining impact on surface water quality. Water samples collected from eight points were analyzed chemically and microbiologically. In water samples from points in the region called the pit mine–waste rock piles, high average oxide-reduction potential value (429–525 mV), high ferrous ion concentration (0.72–12.56 mg L−1), low average pH value (3.37–3.47) and highest average population densities of A. ferrooxidans (59–2,551 MPN mL−1) and A. thiooxidans (833–6,359 MPN mL−1) were detected. These findings indicate that these points are the main places of acid mine drainage and biolixiviation action in the Ore Treatment Unit (UTM). The study reported here also found that water quality in the point considered a link between the UTM and the environment was degraded. These points should be considered as critical sites in the event of a decommissioning act. The average concentration values of fluorite (10.60 mg L−1) and manganese (10.49 mg L−1) in the water samples of treated effluents are above the limits permitted by law. Long-term utilization of these waters is considered to be unhealthy for the local environment and humans.

The acute toxicity of metals to Daphnia similis was determined and compared to other daphnid species to evaluate the suitability of this organism in ecotoxicology bioassays. To verify the performance D. similis in toxicity tests, we also investigated the effect of Pseudokirchneriella subcapitata at 1 x 10(5) and 1 x 10(6) cells ml(-1) on Cd and Cr acute toxicity to the cladoceran. Daphnid neonates were exposed to a range of chromium and cadmium concentrations in the absence and presence of the algal cells. Metal speciation calculations using MINEQL(+) showed that total dissolved metal concentrations in zooplankton culture corresponded to 96.2% free Cd and 100% free Cr concentrations. Initial total dissolved metal concentrations were used for 48 h-LC(50) determination. LC(50) for D. similis was 5.15 x 10(-7) mol l(-1) dissolved Cd without algal cells, whereas with 1 x 10(5) cells ml(-1), it was significantly higher (7.15 x 10(-7) mol l(-1) dissolved Cd). For Cr, the 48 h-LC(50) value of 9.17 x 10(-7) mol l(-1) obtained for the cladoceran in tests with 1 x 10(6) cells ml(-1) of P. subcapitata was also significantly higher than that obtained in tests without algal cells (5.28 x 10(-7) mol l(-1) dissolved Cr). The presence of algal cells reduced the toxicity of metals to D. similis, as observed in other studies that investigated the effects of food on metal toxicity to standard cladocerans. Comparing our results to those of literature, we observed that D. similis is as sensitive to metals as other standardized Daphnia species and may serve as a potential test species in ecotoxicological evaluations.

The present study aimed to investigate the response of several life history parameters (body length and age of primipara, duration of embryonic development, maximum body length, reproduction and survival) of the zooplankton Ceriodaphnia silvestrii while exposed to copper contaminated algae Pseudokirchneriella subcapitata. In order to evaluate chronic exposure on the animal's life history, long-term experimental design was used. Cladocerans were fed with a dietary copper concentration ranging from 3 to 68 fg Cu cell−1. Low waterborne copper exposure (around 10−10 mol L−1 free Cu2+ ions) was kept in the experiments. The results showed that by exposure of cladocerans during 7 days to contaminated food with 68 fg Cu cell−1, a significant reduction in neonate production, survival and body size were obtained. Inhibition on egg production of zooplankton at 38 fg Cu cell−1 were observed in 36 days chronic dietary copper exposure. The importance of entire life cycle study to better evaluate cladoceran responses to chronic dietary metal exposure was demonstrated.

The influence of different densities of the algae Pseudokirchneriella subcapitata on the chronic toxicity of cadmium to Ceriodaphnia dubia was investigated. The importance of algal cells as a source of metal to zooplankton was studied by exposing P. subcapitata cells to free cadmium ions and supplying the algae as food to C. dubia. The results of a bifactorial analysis (metal versus food levels) showed that metal toxicity to zooplankton was dependent on food level. Significant toxic effects on the fecundity and survival of C. dubia were observed at low metal concentrations with high algal density. Algae contaminated with Cd2+ were less toxic to cladoceran than was the Cd2+ in solution. Green algae retained cadmium and released low metal concentration in the test medium. We concluded that algal cells are an important route of exposure to metal and a factor that has an appreciable influence on the expression of metal toxicity to daphnids.

An evaluation was made of the quality of samples of water and sediment collected from a series of reservoirs in the Tietê River (SP), based on limnological and ecotoxicological analyses. The samples were collected during two periods (Feb and Jul 2000) from 15 sampling stations. Acute toxicity bioassays were performed using the test organism Daphnia similis, while chronic bioassays were carried out withCeriodaphnia dubia and Danio rerio larvae. The water samples were analyzed for total nutrients, total suspended matter and total cadmium, chromium, copper and zinc concentrations, while the sediment samples were examined for organic matter, granulometry and potentially bioavailable metals (cadmium, chromium, copper and zinc). The results obtained for the limnological variable, revealed differences in the water quality, with high contribution of nutrients and metals for Tietê and Piracicaba rivers, besides the incorporation and sedimentation, consequently causing a reduction of materials in Barra Bonita reservoir, thus promoting the improvement of the water quality in the other reservoirs. The toxicity bioassays revealed acute toxicity for Daphnia similis only in the reservoirs located below Barra Bonita dam. On the other hand, chronic toxicity for Ceriodaphnia dubia and acute for Danio rerio showed a different pattern, decreasing in magnitude from Barra Bonita to Três Irmãos, demonstrating an environmental degradation gradient in the reservoirs.

The toxic potential of four disinfectant agents (chlorine, ozone, peracetic acid and UV radiation), used in the disinfection of urban wastewater, was evaluated with respect to four aquatic organisms. Disinfection assays were carried out with wastewater from the city of Araraquara (São Paulo State, Brazil), and subsequently, toxicity bioassays were applied in order to verify possible adverse effects to the cladocerans (Ceriodaphnia silvestrii and Daphnia similis), midge larvae Chironomus xanthus and fish (Danio rerio). Under the experimental conditions tested, all the disinfectants were capable of producing harmful effects on the test organisms, except for C. xanthus. The toxicity of the effluent to C. silvestrii was observed to increase significantly as a result of disinfection using 2.5 mg L(-1) chlorine and 29.9 mg L(-1) ozone. Ozonation and chlorination significantly affected the survival of D. similis and D. rerio, causing mortality of 60 to 100 % in comparison to the non-disinfected effluent. In experiments with effluent treated with peracetic acid (PAA) and UV radiation, a statistically significant decrease in survival was only detected for D. rerio. This investigation suggested that the study of the ideal concentrations of disinfectants is a research need for ecologically safe options for the treatment of wastewater.

The toxicity of cadmium and chromium to Pseudokirchneriella subcapitata and Microcystis aeruginosa was evaluated through algal growth rate during 96h exposure bioassays. Free metal ion concentrations were obtained using MINEQL+ 4.61 and used for IC50 determination. Metal accumulations by the microorganisms were determined and they were found to be dependent on the concentration of Cd2+ and Cr6+. IC50 for P. subcapitata were 0.60 µmol L-1 free Cd2+ and 20 µmol L-1 free Cr6+, while the IC50 values for M. aeruginosa were 0.01 µmol L-1 Cd2+ and 11.07 µmol L-1 Cr6+ . P. subcapitata accumulated higher metal concentrations (0.001 -0.05 µmol Cd mg-1 dry wt. and 0.001 -0.04 µmol Cr mg-1 dry wt) than the cyanobacteria (0.001 -0.01 µmol Cd mg-1 dry wt and 0.001 -0.02 µmol Cr mg-1 dry wt). Cadmium was more toxic than chromium to both the microorganisms.

Changes in life cycle parameters (survival, growth, reproduction) and feeding rate of the tropical cladoceran Ceriodaphnia silvestrii as affected by Cu contaminated algae Pseudokirchneriella subcapitata were investigated. The dietary copper exposure ranged from 3 x 10(-15) to 68 x 10(-15) g Cu algal cell(-1). Low waterborne copper exposure (around 10(-10) mol l(-1) free Cu2+ ions) was kept in the experiments. The results show an increasing toxic effect on C. silvestrii with copper increase in algal cells; at the highest copper exposure, all life cycle parameters were significantly affected. A concentration of 38 x 10(-15) g Cu algal cell(-1) reduced egg hatching percentile and the number of neonates produced per female, but did not cause any statistically significant effect on animals survival nor to the number of eggs produced per female. The following sequence of events was observed from the lowest to the highest copper contamination: reproduction, feeding rate, body length and, at last, survival was affected. We conclude that algal cells are an important route of copper exposure and toxicity to cladocerans.

A contínua entrada de metais pesados nos ambientes aquáticos constitui uma potencial ameaça aos ecossistemas naturais devido à ação tóxica direta em organismos aquáticos. Nos ambientes aquáticos, os organismos estão expostos a metais tanto dissolvidos na água como aqueles presentes na cadeia trófica. Um maior conhecimento sobre o papel do alimento como rota adicional de exposição a metais ou como um possível retentor de sua toxicidade para invertebrados aquáticos é necessário. Considerando-se a importância dos metais na contaminação ambiental, bem como a necessidade de melhor entendimento das interações desses elementos nos sistemas aquáticos, o presente estudo visou a avaliar a sensibilidade de espécies fitoplanctônicas (Selenastrum capricornutum e Microcystis aeruginosa) e de espécies zooplanctônicas (Daphnia similis e Ceriodaphnia dubia) aos metais cádmio e cromo e os efeitos tóxicos desses elementos em tais organismos. O crescimento celular, a concentração de clorofila, o biovolume e o peso seco das algas foram analisados quando as espécies algais foram expostas aos metais por meio de testes de toxicidade aguda. Testes de toxicidade aguda e crônica com o zooplâncton aos metais também foram realizados e o efeito de diferentes densidades algais (alta, média e baixa) sobre a toxicidade dos metais aos cladóceros foi avaliado. Além disso, algas foram expostas aos metais, oferecidas como alimento a C. dubia e os efeitos tóxicos crônicos foram investigados. Os resultados demonstraram que S. capricornutum foi mais sensível ao cádmio e M. aeruginosa foi mais sensível ao cromo, sendo essa diferença relacionada à capacidade das algas para reter os metais. Com o aumento de ambos os metais, houve uma diminuição na densidade celular, na taxa de crescimento, na clorofila e no peso seco das algas. A presença de diferentes densidades de S. capricornutum não alterou significativamente o valor da CE(I)50; 48h aos metais para D. similis, mas a elevada densidade de M. aeruginosa reduziu a toxicidade do cádmio para o dafinídeo. A alta densidade de alimento (106 céls/mL) influenciou negativamente a reprodução e a sobrevivência de C. dubia quando exposta a concentrações subletais dos metais em solução. Alimento exposto à metais, quando fornecido em alta e em média densidade, também afetou a sobrevivência e a reprodução dos organismos-teste. Apesar de a água ser uma importante rota de exposição aos metais para os organismos aquáticos, o alimento deve ser considerado uma via de contaminação adicional. The continuous input of heavy metals into aquatic systems constitutes a potential threat to natural ecosystems because of the direct toxic action on aquatic organisms. In aquatic ecosystems, the organisms are exposed to dissolved metals in the water as to metals presents in the food chain. A larger knowledge about paper of food as an additional route of exposure to metals or as possible retainer of its toxicity for aquatic organisms is necessary. Considering the importance of metals in contamination of aquatic ecosystems and the need of better understanding of the interactions of those elements in the aquatic ecosystems as well, the aim of this study was to evaluate the sensibility of phytoplankton species (Selenastrum capricornutum and Microcystis aeruginosa) and zooplankton species (Daphnia similis and Ceriodaphnia dubia) to cadmium and chromium metals and the toxic effects of those elements in such organisms. Analysed of cellular growth, chlorophyll concentration, biovolume and dry weight of the algae were carried out when algal species were exposed to metals. Acute and chronic toxicity tests with the zooplankton were also accomplished and the effect of different algal densities (high, middle and low) on toxicity of metals to cladoceran was evaluated. Alga S. capricornutum was exposed to metals, supplied as food to C. dubia and chronic toxicity effects were investigated. The results demonstrated that S. capricornutum was more sensitive to cadmium and M. aeruginosa was more sensitive to chromium, this difference was related the capacity of the algae to retain metals. Cell density, growth rate, chlorophyll and dry weight of the algae were reduced with increase of both metals. The presence of different density of S. capricornutum does not alter the value of EC50 to metals for D. similis, but high density of M. aeruginosa reduced the toxicity of cadmium for daphnid. High food density (106 cells/mL) influenced negatively on reproduction and survival of C. dubia when this organism was exposed to sublethal concentrations of metals in solution. Food exposed to metals, when it was supplied at high and middle density, also affected survival and reproduction of the test organisms. Although the water to be considered a important route of exposure of metals for aquatic organisms, the food should be considered an additional source of toxicity.

Entre os diversos impactos nos ecossistemas aquáticos, a construção de reservatórios talvez represente um dos principais agentes modificadores, inserindo alterações físicas, químicas e biológicas nos sistemas antes e após a sua construção. No Brasil, tal impacto também é singular, verificando-se o aproveitamento dos mesmos para a construção de barragens, principalmente as construídas em cascatas (sistemas Paranapanema, Tietê e São Francisco por exemplo), sendo que, neste padrão de construção, espera-se, na maioria das vezes, um efeito crescente do controle da qualidade da água, com o primeiro reservatório mais eutrófico que os demais por sua capacidade de reter materiais provenientes dos principais tributários. No estado de São Paulo, na região Sudeste, destacam-se os reservatórios de Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava, e Três Irmãos. Visando avaliar os impactos e contribuir com informações para monitorar as condições ambientais desses reservatórios, foram realizadas coletas de água e sedimento em quatro períodos distintos (outubro/99, fevereiro, maio e julho/00), em 15 estações de coleta, incluindo estações nos rios Tietê e Piracicaba e à montante e à jusante da barragem de cada um dos seis reservatórios, bem como no rio Bauru (um afluente bastante impactado de toxicidade com amostras de água e sedimento, utilizando-se Daphnia similis (em bioensaios de toxicidade aguda) e Ceriophnia dubia (em bioensaios de toxicidade crônica), análises de metais totais na água e biodisponíveis no sedimento, além do monitoramento de variáveis limnológicas (temperatura, pH, condutividade, oxigênio, dissolvido, material em suspensão, clorofila-a, nutrientes totais e dissolvidos). Os resultados obtidos para as variáveis limnológicas, de modo geral, revelaram diferenças na qualidade de água em relação às escalas espacial e temporal (efeitos de fatores climatológicos e hidrodinâmicos-vazão e tempo ) de retenção de água), com elevado aporte de nutrientes pelos rios Tietê e Piracicaba, além da incorporação, da sedimentação e da redução de materiais no reservatório de Barra Bonita, promovendo a melhoria da qualidade da água nos demais reservatórios, caracterizando assim, as primeiras estações como eutróficas e as demais como mesotróficas e oligotróficas. Concentrações de metais totais de água acima do limite estabelecido pela resolução CONAMA 20/1986 foram encontradas, bem como um aumento da fração biodisponível. Os ensaios revelaram toxicidade aguda para Dapnhia similis somente nos reservatórios localizados à justante da barragem de Barra Bonita, o que não seria inicialmente esperado. Tal fato pode estar relacionado às entradas difusas de poluição ou a presença de metais no sistema Tietê, os quais, no primeiro reservatório, estariam mais presentes na forma retida em função de sua maior incorporação (pela maior biomassa e pelo maior tempo de retenção), não causando toxicidade aguda aos organismos devido à parte dissolvida não ser tão elevada. Os resultados de toxicidade crônica, porém, configuraram um padrão diferente, verificando-se toxicidade em ordem decrescente (de Barra Bonita à Três Irmãos), na maioria dos períodos de amostragens, o que demonstra o estado de degradação ambiental nos reservatórios e a necessidade de estudos mais integrados para uma melhor avaliação ambiental. Among the several impacts in the aquatic ecosystems, perhaps the construction of reservoirs represents one of the principal modifier agents, inserting physical, chemical and biological alterations in the systems before and after its construction. In Brazil, such impact is also singular, having verified this application for the construction of reservoirs, mainly the ones built in cascades (Paranapanema, Tietê and São Francisco system, for example) and, in that construction pattern, in most cases, a growing effect of the control of the quality of the water is anticipated, with the first reservoir being more eutrophic than the others for its capacity to retain materials that come from the principal tributary. In the southeast of São Paulo States, Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava and Três Irmãos reservoirs stand out. Seeking to evaluate the impacts and contributing with information to evaluate the environmental conditions of those reservoirs, collections of water and sediment were accomplished in four different periods (October/99, February, May and July/00), in 15 sampling stations, including stations in the Tietê and Piracicaba Rivers and at the specified place after and before the line of the dam, from each one of the six reservoirs, as well as the Bauru River (a very impacted tributary of the Bariri Reservoir ). Toxicity bioassays were accomplished with samples of water and sediment using Daphnia similis (in acute toxicity bioassays) and Ceriodaphnia dubia (in chronic toxicity bioassays), analyses of total metals in the water and bioavailable in the sediment, besides the monitoring of limnological variables (temperature, pH, conductivity, dissolved oxygen, material in suspension, chlorophyll-a, total nutrients and dissolved). The results obtained for the limnological variables, in general, revealed differences in the quality of the water in relation to the spatial and temporary scales (effects of climatological factors and hydrodynamic- flowing out and residence time) with high contribution of nutrients from the Tietê and Piracicaba Rivers, besides the incorporation, the sedimentation and the reduction of materials in the Barra Bonita Reservoir, promoting the improvement of the water quality in the other reservoirs, characterizing, in this way, the first stations as eutrophic and the others as mesotrophic and oligotrophic. Concentrations of total metals in the water above the established limit for the resolution CONAMA 20/1986 were found out, and an increase of the fraction bioavailable of metals was verified as well. The bioassays only revealed acute toxicity for Daphnia similis to the points after the Barra Bonita Reservoir, something not initially awaited for. Such fact can be related to the diffuse entrances of pollution or to the presence of metals in the Tietê System, which, in the first reservoir, would be more present in the form retained in function of their largest incorporation (for the largest biomass and for the largest residence time), not causing acute toxicity to the organisms due to the dissolved part not to being so high. However, the results of chronic toxicity, configured a different partem, being verified toxicity in decreasing order (from Barra Bonita to Três Irmãos), during most of the samplings periods, which demonstrates the state of environmental degradation in the reservoirs and the need for more integrated studies for a better environmental evaluation.

Food availability may affect metal toxicity for aquatic organisms. In the present study, the influence of high, medium and low densities of the algae Pseudokirchneriella subcapitata (10(6), 10(5) and 10(4) cells.mL(-1), respectively) on the chronic toxicity of chromium to the cladoceran Ceriodaphnia dubia was investigated. C. dubia was exposed to a range of chromium concentration from 2.71 to 34.04 microg.L(-1) and fed with algae at various densities. In another experiment, the green alga was exposed to chromium concentrations (94 to 774 microg.L(-1)) and supplied as food in different densities to zooplankton. The survival and reproduction of the cladoceran were measured in these toxicity tests. The IC50 for Cr to P. subcapitata and metal accumulated by algal cells were determined. The results of a bifactorial analysis (metal versus algal densities) showed that metal toxicity to zooplankton was dependent on algal densities. Significant toxic effects on the reproduction and survival of C. dubia were observed at 8.73, 18.22 and 34.04 microg.L(-1) Cr when the test organisms were fed with 10(6) cells.mL(-1) of P. subcapitata. Although the chlorophyta retain low chromium content, a decrease in the reproduction and survival of C. dubia occurred when they were fed with high algal density contaminated with 774 microg.L(-1) Cr. It was concluded that high algal density have an appreciable influence on chromium toxicity to daphnids.

O rompimento da barragem do Fundão contendo rejeitos de mineração de Fe na cidade de Mariana (MG) foi, no final do ano de 2015, um grande desastre socioambiental para o Brasil. Além de ter deixado um rastro de mortes, várias famílias desabrigadas e desempregadas, o derrame do rejeito devastou mais de mil hectares de matas e adentrou diversos corpos d\'água até atingir o oceano Atlântico. Mesmo seis anos após tamanho desastre pouco se sabe ainda sobre os reais impactos toxicológicos provenientes do derramamento dos 34 milhões de m3 de rejeito nos diversos ambientes atingidos. Neste contexto, este trabalho objetivou identificar os efeitos da contaminação ambiental por rejeitos de mineração para comunidades aquáticas de água doce de diferentes níveis tróficos afetadas pela intrusão da lama potencialmente tóxica. Para tal, o rejeito do próprio local foi coletado, caracterizado quanto à composição de metais e testado em sistemas aquáticos representativos de ambientes reais, os mesocosmos, de tal forma que simulasse o impacto causado nos locais adjacentes à barragem rompida. Amostras de água e sedimento foram coletadas para realização de testes laboratoriais agudos e crônicos com organismos representativos dos estratos tróficos, tais como algas (R. subcapitata), cladoceros (C. silvestrii e D. similis), organismos bentônicos (C. sancticaroli e A. inaequalis) e peixes (D. rerio). Tendo em vista as quantidades elevadas de metais que compõem o rejeito quantificadas neste estudo, com destaque para manganês e ferro, foi elaborado um design experimental de testes com a mistura binária destes contaminantes, o qual foi desenvolvido na Universidade de Vrije, em Amsterdã, possibilitando um melhor entendimento dos possíveis efeitos destes compostos presentes no rejeito para o cladócero D. magna, representante da base da cadeia trófica. Os resultados observados indicaram efeitos letais principalmente nos organismos bentônicos e subletais nos organismos planctônicos, evidenciando que a proximidade com o contaminante, que tende a se depositar no fundo dos sistemas aquáticos, causa efeitos nocivos até mesmo à sobrevivência. Os metais testados, apesar de serem essenciais ao desenvolvimento de seres vivos e, muitas vezes serem erroneamente considerados inofensivos, foram considerados tóxicos por causar efeitos subletais em concentrações mensuradas em águas afetadas pela lama. Além disso, tanto isolados quanto em mistura, ambos foram altamente acumuláveis na espécie D. magna. Em conjunto, os dados gerados nesta tese e a discussão proposta nos capítulos subsequentes contribuem para o melhor entendimento dos danos causados à biota aquática presente nos ecossistemas atingidos pelo desastre do rompimento da barragem de Mariana (MG) e, consequentemente, nos leva a refletir sobre a proporção em escala trófica que os efeitos tóxicos podem atingir como será discutido em cada capítulo. At the end of 2015 the Fundão dam rupture containing iron mining tailings in Mariana (MG, Brazil) was the major environmental and social disaster for Brazil. The disaster left several families homeless and unemployed. The tailings spill devastated more than a thousand hectares of forests and entered several bodies of water until reaching the Atlantic Ocean. Even six years later, little is known about the real toxicological impacts resulting from the spill of 34 m3 of waste in the different environments. In this context, this work aimed to investigate the effects of mining tailings on freshwater aquatic communities affected by the input of this potentially toxic mud. To this end, the tailings from the site were collected, characterized as to the composition of metals, and tested in aquatic systems representative of a natural environment, the mesocosms, in such a way as to simulate the impact caused in the adjacent places to the ruptured dam. Water and sediment samples were collected for acute and chronic laboratory tests with representative of trophic strata organism such as algae (R. subcapitata), cladocerans (C. silvestrii and D. similis), benthic organisms (C. sancticaroli and A. inaequalis) and fish (D. rerio). In view of the high amounts of metals quantified in this study, especially manganese and iron, an experimental test design was developed with the binary mixture of these contaminants (developed at the University of Vrije in Amsterdam). This enabled a better understanding of the possible effects of these compounds present in the tailings for the cladoceran D. magna representative of the base of the trophic chain. Lethal effects were observed mainly in benthic organisms and sublethal in planktonic organisms. Evidencing that the proximity to the contaminant, which tends to settle on the bottom, causes harmful effects even on survival. The tested metals, despite being essential to the development of living beings and, many times being erroneously considered harmless, were considered toxic for causing sublethal effects in quantified concentrations in waters affected by the mud. Furthermore, both, isolated and in mixture, were highly accumulative in the D. magna organism. Together, the data generated in this thesis and the discussion proposed in the subsequent chapters contribute to a better understanding of the damage caused to the aquatic biota present in the ecosystems affected by the Mariana dam failure disaster and, consequently, lead us to reflect on the trophic scale proportion that toxic effects can reach.

Com o aumento crescente da demanda energética e o incentivo da utilização dos biocombustíveis, espera-se que a produção da cana-de-açúcar no Brasil cresça ainda mais nos próximos anos. No entanto, apesar das monoculturas contribuírem com a economia do país, diversos problemas ambientais estão relacionados com esta prática agrícola. No caso da produção da cana-de-açúcar, a geração de resíduos (como a vinhaça) e o elevado uso de agrotóxicos, os quais contribuem para contaminação dos diferentes compartimentos ambientais, incluindo os ecossistemas aquáticos, por meio de processos de deriva de pulverização, lixiviação, escoamento e percolação. A partir deste cenário, o objetivo deste trabalho foi avaliar os efeitos da adição da vinhaça e de agrotóxicos amplamente utilizados na produção de cana-de-açúcar, sobre espécies aquáticas tropicais. Para isso, foram avaliados os efeitos ecotoxicológicos da vinhaça e dos agrotóxicos DMA® 806 BR (herbicida) e Regent® 800 WG (inseticida), isolados e em mistura, por meio de testes laboratoriais e modelos ecossistêmicos (mesocosmos), mensurando efeitos reprodutivos, comportamentais, morfológicos, fisiológicos e letais em três níveis da cadeia trófica aquática. Para tal, foram utilizadas as espécimes-teste Raphidocelis subcapitata (produtor primário), Ceriodaphnia silvestrii (consumido r primário) e Danio rerio (consumidor secundário). Os resultados obtidos mostraram que a vinhaça e o inseticida fipronil foram tóxicos para o cladócero e o peixe, eliminando ambas as espécies em doses que estão na faixa das concentrações reportadas no ambiente (48h-CE50 3,9 μg/L e 96hCL50 172 μg/L, respectivamente), causando também efeitos subletais, como reprodução e alimentação. Para alga, somente na exposição laboratorial a vinhaça (1,3% (V/V)) causou efeito inibitório significativo. O herbicida 2,4-D causou efeitos letais em altas doses para D. rerio nos experimentos laboratoriais (> 440 mg/L) e alguns efeitos significativos na alimentação, comportamento e morfologia de brânquias tanto nas doses utilizadas em laboratório quanto em mesocosmos (≤ 447 μg/L). No caso das misturas, para R. subcapitata, a mistura dos agrotóxicos não provocou diferenças no crescimento algal quando comparada aos agrotóxicos isolados, no entanto, a adição da vinhaça teve alto efeito inibitório em laboratório, efeito que não foi significativo com as amostras dos mesocosmos. A vinhaça também potencializou os efeitos da mistura para C. silvestrii, enquanto as misturas binárias apresentaram efeito antagônico em baixas doses. E para D. rerio as misturas binárias foram mais tóxicas que os agrotóxicos isolados, e a adição da vinhaça provocou 100% de mortalidade na espécie. Em conclusão, em um cenário atual de expansão agrícola e afrouxamento de políticas ambientais, a biodiversidade e equilíbrio dos ecossistemas aquáticos tropicais estão em risco. As principais consequências e grande parte da literatura atual sobre as substâncias avaliadas são discutidas neste estudo. With the increasing demand for energy and the incentive to use biofuels, it is expected that the production of sugarcane in Brazil will grow even more in the coming years. Despite that monoculture contribute to the country\'s economy, several environmental problems are related to this agricultural practice. In the case of sugarcane production, the generation of waste (such as vinasse) and the high use of pesticides, which contribute to the contamination of different environmental compartments, including aquatic ecosystems, through spray drift, leaching, runoff and percolation processes, may be highlighted. From this scenario, the objective of this study was to evaluate the effects of the addition of vinasse and pesticides widely used in sugarcane production, on the tropical aquatic species. For this, the ecotoxicological effects of vinasse and the pesticides DMA® 806 BR (herbicide) and Regent® 800 WG (insecticide), isolated and in mixture, were evaluated through laboratory tests and model ecosystems (mesocosms), evaluating reproductive, behavioral, morphological, physiological and lethal effects at three trophic levels of the aquatic food chain. For this, the species Raphidocelis subcapitata (primary producer), Ceriodaphnia silvestrii (primary consumer) and Danio rerio (secondary consumer) were used. The results obtained showed that vinasse and the insecticide fipronil were toxic to the cladoceran and fish, extinguishing both species at doses that are in the range of concentrations reported in the environment (48h-EC50 3,9 μg/L e 96h-LC50 172 μg/L, respectively) also causing sublethal effects such as reproduction and feeding. For algae, only in the laboratory exposure vinasse (1.3% (V/V)) caused a significant inhibitory effect. The herbicide 2,4-D caused lethal effects at high doses for D. rerio in laboratory experiments (> 440 mg/L) and some significant effects on feeding, behavior and gill morphology both at doses used in laboratory and in mesocosms (≤ 447 μg/L). In the case of mixtures, for R. subcapitata, the mixture of pesticides did not cause differences in algal growth when compared to isolated pesticides, however, the addition of vinasse had a high inhibitory effect in the laboratory, an effect that was not significant with the mesocosm samples. Vinasse also potentiated the effects of the mixture for C. silvestrii, while the binary mixtures showed an antagonistic effect at low doses. And for D. rerio the binary mixtures were more toxic than the isolated pesticides, and the addition of vinasse caused 100% mortality in the species. In conclusion, in a current scenario of agricultural expansion and relaxation of environmental policies, the biodiversity and balance of tropical aquatic ecosystems are at risk. The main consequences and much of the current literature on the substances evaluated are discussed in this study.

O aumento do consumo de agrotóxicos, em geral nos países em desenvolvimento cuja base econômica é a agricultura, como no Brasil (primeiro no ranking mundial), tem sido relacionado à expansão da degradação dos ecossistemas e à perda da biodiversidade, principalmente das espécies não alvo, incluindo ainda os riscos inerentes à saúde humana. Além disso, a ausência de políticas e programas mais efetivos relacionados à regulação e uso de agrotóxicos no Brasil, bem como o estabelecimento de normas restritivas baseadas em resultados gerados em países de clima temperado, tornam-se cada vez mais preocupantes, pois podem subestimar os reais riscos da contaminação ambiental por agrotóxicos em ecossistemas tropicais. Nesse contexto, o presente estudo teve como objetivo avaliar os efeitos diretos e indiretos do agrotóxico pyrimethanil, um fungicida utilizado em diversas culturas de climas temperado e tropical, sobre a comunidade aquática tropical, considerando experimentos laboratoriais e o uso de modelos ecossistêmicos para avaliação destes efeitos. Para atender aos objetivos propostos foram realizados testes de toxicidade com as espécies Pseudokirchneriella subcapitata (alga), Ceriodaphnia silvestrii e Daphnia similis (zooplâncton) e Danio rerio (peixes), além de um experimento em mesocosmos, monitorado em longo prazo (durante 15 dias antes e 366 dias após a contaminação), avaliando as variações físicas e químicas, bem como as respostas das comunidades zooplanctônicas e fitoplanctônicas frente à contaminação por pyrimethanil, em uma concentração média de 1,36 mg.L-1. Nos testes de toxicidade, as CEs obtidas foram de 0,67 mg.L-1 (crônica) e 3,26 mg.L-1 (aguda) para C. silvestrii; de 3,65 mg.L-1 (agudo) para D. similis; de 9,65 mg.L-1 para P. subcapitata e para D. rerio os valores obtidos para imobilidade foram de 10,45 mg.L-1 (96h) e 13,77 mg.L-1(48h) e para a mortalidade foram de 27,45 mg.L-1 (96h) e 32,17 mg.L-1 (48h). Pelos resultados dos experimentos em mesocosmos verificaram-se efeitos negativos diretos sobre o zooplâncton (redução da densidade e alteração na composição de espécies) e indiretos sobre o fitoplâncton, decorrentes da diminuição da pressão de pastagem, além do desaparecimento de algumas espécies mais sensíveis. Os efeitos tóxicos observados foram além do período em que foi observada a degradação completa do pyrimethanil, demonstrando o alto impacto do agrotóxico em ecossistemas aquáticos e a complexidade da dinâmica desse tipo de contaminação em ecossistemas naturais. O design experimental revelou-se adequado, gerando informações importantes sobre os impactos dos agrotóxicos nos ecossistemas aquáticos. A partir dos resultados obtidos sugere-se que a utilização de espécies nativas de regiões tropicais seja ampliada nos testes de toxicidade laboratoriais, sendo fundamental que os mesmos sejam complementados com os experimentos em modelos ecossistêmicos, o que permite uma avaliação dos efeitos diretos e indiretos dos contaminantes em nível de população e comunidade, bem como uma melhor compreensão destes efeitos nas funções e serviços ecossistêmicos. The increase in the consumption of pesticides, mainly in developing countries whose economic base is agriculture, as Brazil (first in the world ranking), has been associated to the expansion of ecosystem degradation and biodiversity losses, especially of non-target species, also including the risks to human health. In addition, the absence of policies and effective programs related to the regulation and use of pesticides in Brazil, and the establishment of restrictive standards based on results generated in temperate countries, make it becomes increasingly worrisome because it may underestimate the real risks of environmental contamination by pesticides in tropical ecosystems. In this context, the present study aim to evaluate the direct and indirect effects of the pesticide pyrimethanil, a fungicide used in many temperate and tropical crops, upon a tropical aquatic community, considering laboratory experiments and the use of ecosystem models to evaluate these effects. To achieve the proposed objectives toxicity tests were performed with the species Pseudokirchneriella subcapitata (algae), Ceriodaphnia silvestrii and Daphnia similis (zooplankton) and Danio rerio (fish), as well as an experiment in mesocosms, monitored for a long-term (15 days before and 366 days after infection), evaluating the physical and chemical variations, and also the responses of phytoplankton and zooplankton communities across the pyrimethanil contamination in an average concentration of 1.36 mg.L-1. In toxicity tests, the ECs obtained were 0.67 mg.L-1 (chronic) and 3.26 mg L-1 (acute) for C. silvestrii; 3,65 mg.L-1 (acute) for D. similis; 9.65 mg.L-1 for P. subcapitata; and the values obtained for D. rerio immobility were 10.45 mg.L-1 (96h) and 13.77 mg.L-1 (48h) and mortality were 27.45 mg.L-1 (96h) and 32.17 mg.L-1 (48h). The results of the experiments in mesocosms showed direct negative effects on zooplankton (reduced density and change in species composition) and indirect effects on phytoplankton, resulted from the decrease in grazing pressure in addition to the exclusion of some sensitive species. Even after the complete degradation of pyrimethanil, toxic effects were observed, demonstrating the high impact of this pesticide on aquatic ecosystems and the complexity of the dynamics of this type of contamination in natural ecosystems. The design of the experiment revealed to be appropriate for the study, generating important information about the impacts of pesticides on aquatic ecosystems. From the results, it is suggested an increase in the use of native tropical species in the toxicity laboratory tests. Also, this process should be complemented with experiments in ecosystem models, allowing the evaluation of the direct and indirect effects of contaminants in the population and in community level as well as a better understanding of these effects on ecosystem functions and services.

Este estudo teve como objetivo avaliar a interação entre substâncias húmicas e xenobióticos através de estudos ecotoxicológicos. O principal foco foi avaliar a resposta entre diferentes níveis tróficos em organismos aquáticos (fitoplanctônicos, zooplanctônicos, peixes e macroinvertebrados bentônicos) e terrestres (vegetais superiores, insetos e anelídeos) avaliando os efeitos diretos e indiretos das SH e de sua mistura com xenobióticos sobre os organismos. O reconhecido efeito das SH aumentarem ou reduzirem o efeito tóxico de algumas substâncias foi estudado. Os principais pontos para discussão são: a) SH podem reduzir ou estimular o crescimento algal (P. subcapitata); b) A presença de SH podem proteger os organismos contra efeitos tóxicos de metais, no entanto, a presença de Cd/Cu afeta negativamente o crescimento de C. xanthus. d) Em uma análise integrada de processos de remediação solo/água, a presença de SH afetou negativamente ou positivamente os efeitos tóxicos da atrazina em alguns organismos. A significância das SH como tecnologia é discutida. This study focuses the interaction of humic substances and xenonbiotics, throw ecotixicological studies. The main point was quantify and qualify the ecotoxicological responses of several throphic levels of freshwater (algae, zooplankton, fishes and benthic organisms) and soil organisms (higth plants, insects and annelids) analyzing the direct and indirect effects of humic substances (HS) and their mixture on organisms. The recognized ability of HS on improve or reduce the toxic effect of same substances has been studied. The main points of discussion are: a) humic can be both reduce or stimulate the algal growth (P. subcapitata); b) The presence of HS can be protect aquatic organisms to negative effects of metals. However, the presence of mixture of Cd/Cu affect negatively the growth of C. xanthus; d) In a integrated analysis of remediation process in soil/water microcosm, the presence of HS displayed negative or positive effects on atrazine toxicity for some organisms. The value of humic technology was discussed.

O crescente desenvolvimento populacional, industrial e a expansão agrícola vêm contribuindo de forma significativa para o aporte de nutrientes e metais nos ecossistemas aquáticos, interferindo na composição e estrutura das comunidades, dentre elas as macrófitas, ocasionando desequilíbrio ambiental, com perda das funções e serviços ecossistêmicos. Entre os diversos elementos inseridos de forma direta e indireta nos corpos hídricos, destacam-se fósforo, cobre e zinco, os quais, apesar de serem fundamentais para o metabolismo biológico, quando em excesso tornam-se prejudiciais, requerendo avaliações mais efetivas, de forma a melhor compreender e prevenir os potenciais riscos da exposição biológica a estes elementos estressores. Considerando o acima exposto, o objetivo da presente pesquisa foi avaliar o efeito do metal cobre sobre o desenvolvimento da macrófita Pistia stratiotes e o efeito dos metais cobre e zinco sobre o desenvolvimento e capacidade bioacumuladora da macrófita Azolla filiculoides, em diferentes concentrações de fósforo, por meio de testes ecotoxicológicos. Para tanto, aspectos nutricionais (nitrogênio, fósforo, cobre total e clorofila a e total) e de desenvolvimento (biomassa, TCR, número de folhas nascidas, ganho de diâmetro, altura e largura foliar, número de raízes nascidas, comprimento das raízes principais, clorose e necrose foliar) foram avaliados em estudos laboratoriais para P. stratiotes e aspectos nutricionais (todos acima citados) e de desenvolvimento (biomassa e TCR) para A. filiculoides. Pelos resultados obtidos verifica-se que os metais cobre e zinco, nas concentrações testadas, ocasionaram interferência no desenvolvimento e nutrição das macrófitas, sendo a maior sensibilidade ao cobre observada para P. stratiotes, registrando-se efeitos de maior toxicidade do cobre em relação ao zinco em ambas as macrófitas. Verificou-se, ainda, que o fósforo proporcionou maior proteção a A. filiculoides contra o efeito dos metais conforme o aumento de sua concentração e já no teste ecotoxicológico com P. stratiotes não foram registradas diferenças significativas em função do aumento das concentrações de fósforo. Dessa maneira, conclui-se que o metal cobre causou maior toxicidade às macrófitas do que o zinco, principalmente em concentrações mais baixas de fósforo, verificando-se maior capacidade bioacumuladora da espécie A. filiculoides quando comparada com P. stratiotes. The increasing population and industrial growth and the agricultural expansion have contributed significantly to the supply of nutrients and metals in aquatic ecosystems, affecting the composition and structure of communities, among them the macrophytes, causing environmental imbalance, with loss of ecosystem functions and services. Among the various elements inserted directly and indirectly on water bodies, phosphorus, copper and zinc stand out, which, despite being fundamental to the biological metabolism, when in excess become harmful, and assessments that are more effective are required to better understand and prevent the potential risks of biological exposure to these stressors. Considering the above, the objective of this research was to evaluate the effect of copper metal on the development of the macrophyte Pistia stratiotes and the effect of copper and zinc metals on the development and the bioaccumulation capacity of the macrophyte Azolla filiculoides, in different concentrations of phosphorus, through ecotoxicological tests. To do that, nutritional (nitrogen, phosphorus, copper total and chlorophyll a and total) and development (biomass, RGR, number of leafs born, diameter gain, leaf height and width, number of roots born, length of the main roots, leaf chlorosis and necrosis) aspects were evaluated in laboratory studies for P. stratiotes and nutritional (all above) and development (biomass and RGR) aspects for A. filiculoides. From the results obtained it appears that the metals copper and zinc, on the tested concentrations, caused interference in the development and nutrition of the macrophytes, where more sensitivity to copper was observed for P. stratiotes, and the effects of enhanced toxicity of copper relative to zinc in both macrophytes. It was also found that the phosphorus provided greater protection to A. filiculoides against the effects of metals as its concentration was increased and, on the ecotoxicological test with P. stratiotes, no significant differences where found with the increasing concentrations of phosphorus. Thus, it is concluded that the copper metal has caused more toxicity to macrophytes than zinc, especially at lower concentrations of phosphorus, and was verified a greater bioaccumulation capacity on the A. filiculoides species when compared to P. stratiotes.

O cromo é o sétimo metal mais abundante na crosta terrestre e ocorre naturalmente nos diversos compartimentos ambientais, porém o intenso uso deste metal em atividades industriais tem aumentado a liberação deste contaminante, ocasionando alterações na estrutura e funcionamento dos ecossistemas terrestres e aquáticos. Considerando as diferentes formas de exposição ao metal pelos organismos, procurou-se avaliar os efeitos do cromo nas populações fitoplanctônica e zooplanctônica e nas interações tróficas entre ambas, com base em aspectos estruturais e fisiológicos. Para tanto, foram realizados ensaios ecotoxicológicos com duas espécies de algas (Pseudokirchneriella subcapitata e Chlorella vulgaris), avaliando efeitos na densidade celular, concentração de pigmentos e composição bioquímica, além de ensaios com organismos zooplanctônicos (Cladocera Ceriodaphnia dubia e Ceriodaphnia silvestrii) expostos a diferentes vias de contaminação, como água contaminada, alimento contaminado e a combinação de ambas as situações (água e alimento contaminados), avaliando efeitos na sobrevivência, fecundidade, taxa de alimentação e composição bioquímica. Os resultados obtidos demonstraram que o cromo, nas condições testadas, afetou o crescimento, a concentração de pigmentos e a composição bioquímica das algas P. subcapitata e C. vulgaris. Nos ensaios realizados com C. dubia e C. silvestrii, os diferentes tratamentos com cromo não alteraram a sobrevivência destas espécies, porém, nos tratamentos com meio aquoso contaminado com cromo e exposição combinada (meio aquoso e alimento contaminados com cromo) houve redução na fecundidade e diminuição da taxa alimentar destes organismos. Redução no crescimento populacional e aumento de proteínas, carboidratos e lipídeos totais de C. dubia e C. silvestrii também foram relacionados à presença de cromo. Conclui-se, portanto, que o cromo, nas condições testadas, foi tóxico para as espécies fito e zooplanctônicas, podendo causar alterações nas cadeias tróficas dos ecossistemas aquáticos. Chromium is the seventh most abundant metal in the earth\'s crust and occurs naturally in various environmental compartments, but the heavy use of this metal in industrial activities has increased the release of this contaminant, causing changes in the structure and functioning of terrestrial and aquatic ecosystems. Considering the different forms of exposure to metal by organisms, sought to evaluate the effects of chromium on phytoplankton and zooplankton populations and trophic interactions between them, based on structural and physiological aspects. For this, ecotoxicological tests were conducted with two species of algae (Pseudokirchneriella subcapitata and Chlorella vulgaris), assessing effects on cellular density, pigment concentration and biochemical composition, and tests with zooplankton (Cladocera Ceriodaphnia dubia and Ceriodaphnia silvestrii exposed to different ways of contamination, such as contaminated water, contaminated food and a combination of both situations (contaminated water and food), evaluating effects on survival, fertility, feed rate and biochemical composition. The results showed that chromium under the conditions tested, affected the growth, pigment concentration and biochemical composition of the algae P. subcapitata and C. vulgaris. For tests with C. dubia and C. silvestrii, the different treatments with chromium did not affect survival of these species, however, in treated aqueous medium contaminated with chromium and combined exposure (aqueous and food contaminated with chromium) there was a reduction in fecundity and decreased feed rate of these organisms. Reduction in population growth and increased protein, carbohydrate and lipid of C. dubia and C. silvestrii were also related to the presence of chromium. Therefore, it is concluded that chromium, in the conditions tested, was toxic to phytoplankton and zooplankton species, may cause changes in trophic chains of aquatic ecosystems.

A presente pesquisa teve por objetivos principais: (1) estudar a bioacumulação do metal cromo (40-50 \'mü\'g/L) na Clorophyceae Pseudokirchneriella subcapitata (Korshikov) Hindak 1990 e dos metais cobre (2-10 \'mü\'g/L) e cromo (1-6 mg/L) na macrófita Pistia stratiotes L.; (2) avaliar os mecanismos de detoxificação, as estratégias de defesa e tolerância de Pistia stratiotes L., visando recomendar seu uso na fitorremediação; ambos através do uso do Delineamento Composto Central (DCC) e Metodologia de Superficie de Resposta (MSR), e (3) estudar a dinâmica de remoção de nutrientes em wetlands construídos, plantados e não plantados com as macrófitas Typha sp. e Phragmites sp., submetidos a diferentes regimes de fluxo e condições hidráulicas de operação. A bioacumulação de cromo em P. subcapitata e sua relação com o biovolume demonstraram uma possível estratégia de detoxificação. P. stratiotes desenvolve uma bioacumulação mais intensa nas raízes, resultados que são confirmados pela peroxidação de lipídios e a indução do estresse oxidativo causado pelo cromo. As enzimas catalase e glutationa redutase, induzidas pelo cobre em P. stratiotes, também apresentaram atividade mais intensa nas raízes. O teor de clorofila, em geral apresentou aumento nos tempos iniciais e decresceu no decorrer do tempo, em concentrações mais elevadas de cromo e cobre. Na análise da emissão de fluorescência da clorofila, o rendimento fotossintético e o índice de vitalidade foram os parâmetros mais sensíveis ao estresse causado por cromo em P. stratiotes. Os resultados obtidos na pesquisa com o DCC e a MSR permitem recomendar seu uso na ecotoxicologia aquática, pois podem gerar modelos preditivos de toxicidade; ampliar a compreensão dos mecanismos de detoxicaçao; reduzir o número de experimentos sem perder a confiabilidade dos dados e reduzir a geração de resíduos. Nos estudos realizados com os wetlands construídos, os parâmetros físico-químicos avaliados revelaram variação sazonal durante o período experimental (verão/2007, invemo/2008 e verão/2008). Typha sp. e Phragmites sp. estão entre as plantas mais comumente utilizadas nos wetlands construídos e sua presença amplia as condições de filtração do sistema, mas a eficiência da espécie na remoção dos nutrientes (amônia e fosfato) depende do regime de fluxo e das condições hidráulicas aplicadas. Os sistemas com fluxo subsuperficial com a superfície livre de água foram os wetlands que desempenharam melhor capacidade na remoção de nutrientes. Uma vez que a poluição dos corpos d\'água tem sido um problema constante na atualidade, estudos como estes oferecem subsídios para propostas futuras de preservação e recuperação ambiental, além de ampliar os conhecimentos sobre as macrófitas e sua aplicação na descontaminação ambiental em corpos d\'água e em sistemas de depuração de águas residuárias. This research had as main objectives: (1) study the bioaccumulation of chromium metal (40- 50 \'mü\'g/L) in Clorophyceae Pseudokirchneriella subcapitata (Korshikov) Hindak 1990 and of copper (2-10 \'mü\'g/L) and chromium (1-6 mg/L) in the macrophyte Pistia stratiotes L. (2) study the mechanisms of detoxification, defense strategies and tolerance of Pistia stratiotes L. in order to recommend their use in phytoremediation, both through the use of Central Composite Design (DCC) and Response Surface Methodology (RSM), and (3) study the dynamics of nutrient removal in constructed wetlands, planted and unplanted with macrophytes: Typha sp. and Phragmites sp. subjected to different flow regimes and hydraulic conditions of operation. The bioaccumulation of chromium in P. subcapitata and its relation to biovolume shows a possible strategy for detoxification. P. stratiotes develops a more intense bioaccumulation in roots and these results are confirmed by lipid peroxidation and induction of oxidative stress caused by chromium. The enzymes catalase and glutathione reductase induced by copper in P. stratiotes, also showed the strongest activity in the roots. The chlorophyll content in general showed an increase in early and decreased over time, in higher concentrations of chromium and copper. In analyzing the fluorescence emission of chlorophyll, the photosynthetic yield and the index of vitality were the parameters most sensitive to stress caused by chromium in P. stratiotes. The results obtained in research with the DCC and MSR allowed to recommend their use in aquatic ecotoxicology, because they allow: to generate predictive models of toxicity, the simulation of such models expanding the understanding of the mechanisms of detoxification; reduce the number of experiments without losing the reliability of data and reducing waste generation. In studies with constructed wetlands, the physicochemical parameters evaluated showed seasonal variation observed during the experimental period (summer/2007, winter/2008, summer/2008). Typha sp. and Phragmites sp. are among the most commonly used plants in constructed wetlands, and its presence extends the conditions of filtration system, but the efficiency of the species in the removal of nutrients (ammonia and phosphate) depends on the flow regime and hydraulic conditions applied in the system. The systems with subsurface flow with free surface water wetlands that have been played better capacity in removing nutrients. Pollution of water bodies has been a constant problem at the moment, and studies like these provi de input for future proposals for the preservation and environmental restoration, in addition to expanding our knowledge on the macrophytes, and its application in environmental remediation in water bodies and systems purification of wastewater.

A bacia hidrográfica do Ribeirão das Antas inicia-se na represa das Antas, construída em 1982. A represa das Antas recebe os efluentes tratados da UTM (Unidade de Tratamento de Minério), procedentes de drenagens ácidas geradas em pilhas de rejeitos de urânio. Foi realizada a caracterização limnologica deste corpo aquático visando a determinar o impacto ambiental causado por efluente de mina de urânio lançados pela UTM sobre a represa das Antas. Realizou-se coletas de água durante 1 ano nos pontos Cabeceira-Cab, P41, P14Superfície-P14S e P14Fundo-P14F, sendo avaliadas as variáveis físicas, químicas e biológicas. De acordo com os resultados obtidos para o Índice de estado trófico este corpo aquático foi classificado como oligotrófico e para o Índice de saprobidade foi considerado betamesosapróbico com qualidade da água Classe II. Os resultados das análises químicas mostraram teores elevados de fluoreto, manganês, zinco e sulfato no P41 seguido dos pontos P14S e P14F, estando acima do permitido pela legislação vigente para água de classe II. Estes resultados indicaram possível falha no sistema de tratamento de efluentes desta instalação nuclear e possível impacto ambiental, uma vez que, os menores valores de Índice de diversidade e biomassa média para o protozooplâncton foram detectados no ponto P41. Ribeirão das Antas hidrographic basin starts on Antas reservoir which was built in 1982. The Antas reservoir receives treated effluents from the UTM (Mineral Unit Treatment), from acid mine drainage generated in piles of uranium waste. Limnological characterization of this aquatic body was done to determine the environmental impact caused by uranium mine effluents. Sampling campaigns were made during one year at the Cab, P41, P14S, and P14F points. Physical, chemical, and biological variables were evaluated. According with the Tropic State Index results obtained this aquatic body was classified as oligotrophic and the saprobity Index classified the water as betamesosaprobic, class II water quality. These results show failures in this nuclear installation effluent treatment system and possible environmental impact, since lower diversity index values and protozooplankton average biomass were detected at P41 point.