La formation des sous-produits de chloration dans les piscines couvertes dépend de nombreux paramètres cinétiques et hydrauliques. Cette étude propose le développement d’un modèle de prédiction de la formation de certains sous-produits de chloration et de leur transfert dans l’air. La construction du modèle est basée sur le couplage de constantes cinétiques déterminées à l’échelle laboratoire avec des modèles hydrauliques caractérisant les écoulements dans le bassin. Afin de calibrer et de valider les modèles, un bassin expérimental à l’échelle 1/10ème a été mis en place. Par ailleurs, une méthode de mesure des concentrations des sous-produits de chloration dans l’eau et dans l’air par Membrane Inlet Mass Spectrometry a été évaluée. La représentativité et la reproductivité des expériences réalisées sur le bassin ont été étudiées. À l’échelle laboratoire, les constantes cinétiques de consommation du chlore, de formation du chloroforme et de formation du dichloroacétonitrile par chloration du Body Fluid Analogue utilisé pour mimer les apports organiques des baigneurs ont été déterminées. Le comportement hydraulique du bassin a été modélisé par une série de réacteurs idéaux. Cette modélisation a été validée par la réalisation d’expériences de traçage sur le bassin expérimental. Enfin, les constantes de transfert eau-air des sous-produits de chloration volatils ont été déterminées et comparées avec plusieurs modèles de la littérature. Les résultats obtenus montrent que les modèles permettent de prévoir de façon satisfaisante l’évolution des paramètres modélisés. Le bassin expérimental constitue également un outil prometteur pour la calibration de modèles et l’évaluation de solutions de traitement. / The formation of chlorination by-products in swimming pools depends on many kinetic and hydraulic parameters. This study presents the development of a predictive model for the formation of chlorination by-products as well as their water-to-air transfer. The model is based on the coupling of kinetic rates determined in batch with hydraulic models which describe the flows in the basin. A pilot pool unit has been built in order to collect experimental data for the calibration and validation of the models. Moreover an analytical method by Membrane Inlet Mass Spectrometry has been assessed. The representativeness and the reproducibility of experiments performed on the pilot pool unit have been described. Kinetic rates for chlorine consumption, chloroform formation and dichloroacetonitrile formation have been studied at lab scale, based on chlorination experiments of a Body Fluid Analogue, a mix of chemicals which reproduces human intakes in swimming pools. The hydraulic behavior of the basin has been modeled by a series of ideal reactors. The model has been validated by comparison with tracer-based experiments. Finally, water-to-air transfer rates have been determined and compared with models from the literature. The modeled parameters were satisfactorily modeled. Moreover the pilot pool unit has been demonstrated to be useful in calibrating models or in assessing treatment solutions.

A escassez de água e a grande geração de esgoto doméstico com necessidade de tratamento estimulam o uso de águas residuárias na agricultura. A irrigação por gotejamento caracteriza-se como um sistema seguro para esta finalidade, mas possui como barreira tecnológica o entupimento dos gotejadores. Neste trabalho, objetivou-se selecionar modelos de gotejadores e manejos mitigadores do entupimento por uso de água residuária oriunda de tratamento secundário de esgoto doméstico. Desenvolveu-se o estudo em três etapas: (I) a caracterização de 15 modelos de gotejador novos, (II) a préseleção dos emissores e (III) a seleção da combinação manejo e modelo. Os manejos foram controle, cloração a 0,5 mg L-1 de cloro residual livre ao final da irrigação medido ao final do sistema, ar comprimido a 1,96 kPa na entrada dos emissores e a combinação de cloração e ar comprimido, utilizando-se filtragem de areia (De = 0,59 mm), disco (120 mesh) e tela (200 mesh) em todos os tratamentos. Procederam-se avaliações de vazão e cálculos de coeficiente de variação de vazão (CVq) e de grau de entupimento (GE). Os modelos apresentaram coeficiente de variação de fabricação aceitável e diferentes sensibilidades ao entupimento. O entupimento foi parcial, ocorreu de maneira desuniforme, independente da uniformidade de distribuição de água (UD) do emissor novo, e surgiu pela formação de biofilme bacteriano associado a sólidos dissolvidos. Houve aumentos de vazão em alguns modelos. A cloração reduziu o grau de entupimento ao longo do tempo e evitou o entupimento total em emissores. O modelo B associado à cloração apresentou a maior probabilidade de encontrar emissores na faixa de 5 % de variação de vazão em relação aos novos e o modelo M associado à filtragem ou a tratamentos com ar comprimido, as menores probabilidades. Os manejos mostraram-se semelhantes quanto ao GE e ao CVq e obtiveram-se valores de UD inferiores a 60 %, CVq superiores a 20 % e GE superiores a 5 %. Finalmente, de acordo com o objetivo, selecionou-se o modelo B associado à cloração como a combinação que melhor atenuou o entupimento dos emissores. / The sustainable management of water resources, given the current and projected severe water shortages, requires that appropriate methods of water usage be implemented. One of these is the application of treated wastewater to agricultural land using drip irrigation systems, which is safe and among the most resource efficient methods of irrigation. However, the use of drip irrigation with wastewater is constrained by the potential for clogging in the emitters. To elucidate the mechanism of clogging, fifteen drip emitters models from different manufacturers were tested with secondary treated wastewater in the laboratory and two field experiments were conducted to evaluate emitters and treatments according to the degree of clogging (DC) and flow rate coefficient of variation (CVq). The treatments were control (filtrage only), chlorination (0.5 mg L-1 free residual chlorine injected at the end of each irrigation cycle), compressed air (1.96 kPa in the inlet drippers) and the chlorine and compressed air combination. The manufacture coefficient of variation was acceptable and different clogging susceptibility. The clogging was partial, non-uniform and was caused by biofilm with dissolved solids. Some drippers with overflow rates were noted. The chlorination decreased clogging overtime and reduced the complete clogging. The dripper model B (pressure compensated, flat and inserted in the line, with rectangular elastic membrane over a 30 mm passageway, 0.8 mm narrowest aperture, 1.61 L h-1 under 98 kPa) with chlorination was identified as having the best performance, with the highest number of emitters with a flow rate within five percent of the flow rate when new, and the dripper model M with chlorination was the worst performance with the lowest percent. The filtrage, chlorine and air treatments did not have a statistically significant affect in the DC or CVq. Distribution uniformities higher than 60 %, CVq higher than 20 % and DC higher then 5 % were found. Finally, according to the purposed, It was selected the dripper model B with chlorination as the best combination to mitigate the clogging

O aumento da incidência de florações de cianobactérias potencialmente tóxicas nos mananciais de abastecimento, favorecidas pelo elevado aporte de nutrientes nos corpos d\'água, compromete a qualidade da água de consumo e põe em risco a saúde humana e animal, além de elevar os custos do tratamento de água. A pré-cloração, tem se mostrado uma ótima opção tanto na inativação de cianobactérias como na remoção de cianotoxinas dissolvidas. No entanto, sob certas condições, pode causar lise celular e promover a liberação das toxinas no meio. O objetivo deste trabalho foi avaliar em escala laboratorial, o efeito da pré-cloração, utilizando como agente oxidante o hipoclorito de sódio, sobre a integridade celular de uma linhagem tóxica de Microcystis aeruginosa (LTPNA 08), por citometria de fluxo, e sobre a subsequente liberação e degradação das microcistinas (LR e RR) por LC-MS/ MS. Diferentes dosagens de cloro (0,05, 0,5, 1, 1,5, 2, 2,5, 3, 4 e 8 mg.L-1), tempos de contato (0, 15, 30 e 60 minutos) e densidade celular (1x106 células.mL-1 para os ensaios de jarros e 3,5 x106 células.mL-1 para o ensaio de viabilidade celular) foram utilizadas neste estudo. Os resultados obtidos nos ensaios de jarros mostraram remoções de microcistinas acima de 70% após 60 minutos de exposição ao oxidante, com 100% de remoção em doses de 2,5 e 3 mg Cl2.L-1. Valores de CT (concentração x tempo) acima de 40,66 mg.min.L-1 foram necessários para degradar as microcistinas a concentrações abaixo de 1,0 µg.L-1, exigidos pela organização mundial de saúde (WHO) e pela legislação brasileira de potabilidade da água (Portaria MS nº 2914/2011). Não foi possível verificar a lise celular por microscopia óptica, no entanto, na análise por HPLC-DAD verificou-se degradação de mais de 70% da clorofila-a em todas as dosagens testadas, após 60 minutos de exposição, com a completa degradação nas concentrações de 2,5 e 3 mg.L-1 Cl2, indicando dano celular. Nos ensaios por citometria de fluxo, foi verificada a perda da integridade celular com o aumento da dosagem de cloro aplicada, observando-se a permeabilidade celular máxima, sem a desintegração da célula, na concentração de 2,5 mg.L-1 Cl2. Concentrações de 4 e 8 mg.L1 Cl2 promoveram a lise total das células, impossibilitando a permanência do marcador na célula. A perda dos pigmentos clorofila a e ficocianina ocorreram em concentrações de acima de 2,5 e acima de 1,5 mg.L-1 Cl2, respectivamente. O presente trabalho reforçou a eficiência da cloração na degradação das toxinas e os resultados obtidos podem ajudar as autoridades competentes a otimizar as práticas de cloração utilizadas no pré-tratamento da água. / The increased incidence of blooms of potentially toxic cyanobacteria in supply sources, favored by high input of nutrients in water bodies, compromises the quality of drinking water and affect human and animal health, besides increasing water treatment costs. The pre-chlorination, has proved a great choice both in the inactivation of cyanobacterial cells as in removing dissolved cyanotoxins. However, under certain conditions, can cause cell lysis and release toxins. The objective of this study was to evaluate in laboratory scale, the effect of pre-chlorination, using sodium hypochlorite, on cell integrity of toxic Microcystis aeruginosa (LTPNA 08) using flow cytometry, and the subsequent release and degradation of microcystins (LR and RR) by LC-MS / MS. Different chlorine doses (0.05, 0.5, 1, 1.5, 2, 2.5, 3, 4 and 8 mg.L-1), contact times (0, 15, 30 and 60 minutes) and cell density (1x106 células.mL-1 for jar-test and 3.5 x106 células.mL-1 for cell viability assay) were used in this study. The results obtained in the jar- test showed degradations up to 70% after 60 minutes of exposure, with complete degradation at chlorine doses of 2,5 e 3 mg.L-1. Chlorine exposure (CT) values over 40,66 mg.min.L-1 were required for oxidation of microcystin LR and RR to concentrations below the World Health Organization (WHO) and Brazilian legislation for water potability (Portaria MS nº 2914/2011) guideline value of 1µg.L-1. No differences in cell number was observed by microscopy, however, analysis by HPLC-DAD found chlorophyll-a reductions of more than 70% in all dosages tested after 60 minutes exposure, with values below the limit of quantification for concentrations of 2.5 and 3 mg.L-1 Cl2, indicating cell damage. In assays using flow cytometry, loss of cell integrity was observed with increasing chlorine concentration. The maximum cell permeability without cell disintegration was observed at a concentration of 2.5 mg.L-1 Cl2. Concentrations of 4 and 8 mg.L-1 Cl2 lead to complete cell lysis, making impossible the permanence of SYTOX Green in the cell. The loss of pigment chlorophyll a and phycocyanin occurred in concentrations above 2.5 and 1.5 mg.L-1 Cl2, respectively. This study reinforced the efficiency of chlorination in the toxins degradation and the results can help the water authorities to optimize the chlorination practices used in the pretreatment of water.

Este projeto de pesquisa foi desenvolvido visando quantificar possíveis distúrbios de vazão em emissores do tipo gotejador (irrigação localizada) submetidos à aplicação de cloro livre e acidificação em condições estática e dinâmica de fluxo de água no sistema. O experimento foi realizado no período de setembro de 2005 a junho de 2006, utilizando-se 14 modelos de gotejadores autocompensantes com suas respectivas linhas gotejadoras montadas em uma bancada de ensaios em estrutura metálica. Os tratamentos utilizados no experimento foram: a) aplicação dinâmica de 100 mg L-1 de cloro livre com pH na faixa de 5,5 a 6,0; b) aplicação estática de 100 mg L-1 de cloro livre com pH na faixa de 5,5 a 6,0; c) aplicação de ácido nítrico com pH na faixa de 2,0 a 3,0 durante ½ h (sistema pressurizado); d) aplicação de ácido nítrico com pH na faixa de 2,0 a 3,0 durante 12 h (sistema pressurizado). Foram realizadas curvas vazão versus pressão para cada tratamento em três diferentes temperaturas da água (15, 25 e 40° C). O delineamento experimental utilizado foi o inteiramente aleatorizado em esquema fatorial, com utilização dos testes ?F? para análise de variância e Tuckey, a 5% de significância, para comparação de médias e análise de regressão. Os resultados obtidos mostram que para o tratamento da água com 100 mg L-1 de cloro livre em condição dinâmica, ocorreu um decréscimo de 10 a 20% em média da vazão (L h-1) para alguns modelos de gotejadores mais sensíveis aos produtos químicos, sendo que o modelo I apresentou redução drástica de vazão na ordem de 100% em virtude do bloqueio total do labirinto do emissor, em decorrência do aumento de 112% do volume da membrana após 2688 h de aplicação contínua de cloro. Os tratamentos estáticos não apresentaram variações acentuadas de vazão média (L h-1), coeficiente de variação (%), uniformidade de distribuição (%), Vazão Relativa (%) e Grau de Entupimento (%). Verificou-se relação linear entre a vazão e a temperatura da água para os gotejadores novos, sendo que após a aplicação dos diferentes tratamentos, as curvas vazão versus pressão para cada modelo de gotejador sofreram influência tanto da pressão quanto da temperatura de maneira distinta. / This research project was developed to quantify possible flow rate variation in emitters (drip irrigation) submitted to the application of free chlorine and acidification under static and dynamics conditions of water flow. The experiment was accomplished in the period of September, 2005 to June, 2006, being analyzed 14 models of pressure compensating emitters set up in a metallic bench. The treatments used in the experiment were the following ones: a) dynamic application of 100 mg L-1 of free chlorine with pH 5,5 to 6,0; b) static application of 100 mg L-1 of free chlorine with pH 5,5 to 6,0; c) application of acid nitric with pH 2,0 to 3,0 during ½ h (pressurized system); d) application of acid nitric with pH 2,0 to 3,0 during 12 h (pressurized system). The operating pressures and emitter model combination were: 50, 100, 200, 300, 400 kPa for emitters A to N, in three different water temperatures (15, 25 and 40° C). The obtained values of flow rate were used to calculate the CUD, CV, relative flow rate, the percentage of drippers in each flow rate range, and the number of the drippers completely clogged. The statistical analysis of the treatments were accomplished by Tukey test at 5% probability. The obtained results show that for the treatment of the water with 100 mg L-1 of free chlorine in dynamic condition, a reduction from 10 to 20% of the flow rate (L h-1) occurred for some models more sensitive to chemical products. Model I presented drastic reduction of flow rate in the order of 100% by total blockade of the labyrinth of the emitter, due to the increase of 112% of the volume of the membrane after 2688 h of continuous application of 100 mg L-1 of chlorine free with pH 5,5 to 6,0. The static treatments didn\'t present accentuated variations of medium flow rate (L h-1), variation coefficient (%), distribution uniformity (%), relative flow rate (%) and degree of blockage (%). For pressure compensating emitters, where the discharge sensitivity to temperature is insignificant, after the application of the different treatments, the measured discharge/pressure relationship for each emitter model was sensitive to pressure as well to temperature.

Entre as principais dificuldades que os sistemas de tratamento de esgotos domésticos compostos por lagoas de estabilização enfrentam para atender as exigências impostas pela Resolução CONAMA 357/2005 podem se destacar as concentrações elevadas de nitrogênio amoniacal, fósforo e coliformes fecais e totais. Estes últimos, quando os sistemas utilizam corpos receptores classe 2 ou 3 geram a necessidade de desinfecção. Dentre as diversas tecnologias disponíveis para a desinfecção dos esgotos, a cloração é bastante atrativa pelo custo reduzido, em relação às outras tecnologias, bem como pela elevada experiência que as companhias e municipalidades possuem neste tipo de sistema, advinda dos sistemas de tratamento de água. Dentre os sistemas de cloração, o uso de hipoclorito de sódio torna-se interessante pela segurança, simplicidade das instalações e de operação. A desvantagem do uso deste tipo de sistema se dá na possibilidade da formação de subprodutos tóxicos, dentro os quais pode-se destacar os trihalometanos (THMs) e os ácidos haloacéticos (AHAs), porém esta formação pode ser teoricamente reduzida pela presença de elevadas concentrações de nitrogênio amoniacal nos efluentes destes sistemas, por sua reação preferencial com o cloro, na formação de cloraminas. Outras possibilidades de redução na formação é reduzir a concentração de precursores, reduzir a dosagem de cloro e utilizar método de descloração dos efluentes após a desinfecção. Este trabalho, ambientado no desenvolvimento das pesquisas do Edital 4 do PROSAB/FINEP (Programa Nacional de Pesquisa em Saneamento Básico), desenvolveu testes de desinfecção em efluentes de lagoas anaeróbias e facultativas utilizando como desinfetante hipoclorito de sódio, em dosagens de 8,0 mgCl/L e 12,0 mgCl/L. Desenvolveu também testes de desinfecção com efluentes anaeróbios e facultativos pós-tratados por meio de coagulação/floculação/sedimentação e coagulação/floculação/flotação com ar dissolvido, com dosagens de 2,0 mgCl/L e 4,0 mgCl/L. Para todos os testes de desinfecção foram realizados também testes de descloração das amostras. Desta forma foi possível estudar, dentro de uma faixa limitada, as possibilidades de reduzir a formação de subprodutos tóxicos na desinfecção de efluentes de lagoas de estabilização com hipoclorito de sódio. Nas amostras foram determinados por meio de cromatografia gasosa as concentrações dos THMs e AHAs. Por meio das metodologias do Standard Methods 20th Edition foram realizadas as análises físico-químicas dos parâmetros pH, temperatura, DQO, DBO, Ntotal, N-NH3, NTK, cloro livre, cloraminas, coliformes e outros microrganismos indicadores. A formação de THMs se mostrou bastante pequena, em média abaixo dos 20,0 µg/L em todos os testes, aparentemente devido às elevadas concentrações de N-NH3, da ordem de 30,0 mg/L. O mesmo não ocorreu com os AHAs. Em muitos testes a concentração encontrada de AHAs totais superou o padrão de 80,0 µg/L preconizados pela USEPA para água potável, e aqui adotado como padrão comparativo. A descloração reduziu em média 52% a concentração de AHAs nos testes, colocando quase todas as amostras dentro do padrão de 80,0 µg/L. Os bioensaios mostraram que a presença de cloro livre nas amostras eleva a toxicidade aguda em Daphnia similis provocada pelos efluentes e que a cloração seguida de descloração produz efluentes com toxicidade inferior à toxicidade dos efluentes apenas clorados e toxicidade também inferior àquela dos efluentes sem cloração. / The main difficulties that the stabilization ponds for sewage treatment systems face to meet the requirements imposed by CONAMA Resolution 357/2005 can highlight the high concentrations of ammonia nitrogen, phosphorus and fecal and total coliform. When the systems use receivers water bodies Class 2 or 3 generate the need for disinfection. Among the different technologies available for the disinfection of sewage, the chlorination is very attractive at reduced cost compared to other technologies, as well as the high experience that companies and municipalities have in this type of system, because the water treatment systems. About the chlorination technologies, the use of sodium hypochlorite becomes interesting for security, simplicity of installation and operation. The disadvantage of using this type of system is given the possibility of formation of toxic by-products, within which you can highlight the trihalomethanes (THMs) and haloacetic acids (AHAs), but this formation can theoretically be reduced by the presence of high concentrations of ammoniacal nitrogen in effluents of these systems, for its preferential reaction with the chlorine in the formation of cloraminas. Other possibilities for reducing the training is to reduce the concentration of precursors (organic matter), reduce the dosage of chlorine and use dechlorination method after disinfection. This work, developed in PROSAB / FINEP (National Program for Research on Sanitation) research announcement number 4, developed tests for disinfection of anaerobic and facultative ponds effluents using sodium hypochlorite as a disinfectant, in concentrations of 8.0 mgCl/L and 12.0 mgCl/L. Were also developed tests for disinfection with anaerobic and facultative ponds effluents post-treated by coagulation / flocculation / sedimentation and coagulation / flocculation / flotation with dissolved air, with concentrations of 2.0 mgCl/L and 4.0 mgCl/L. For all of disinfection tests were also conducted dechlorination tests. This made it possible to study the possibilities of reducing the formation of toxic byproducts of the stabilization ponds effluents disinfection with sodium hypochlorite. The THMs and AHAS concentrations were determined by gas chromatography. Through the methods of Standard Methods 20th Edition analyses were carried out physical-chemical parameters of pH, temperature, COD, BOD, total nitrogen, ammoniacal nitrogen, total Kjeldhal nitrogen, free chlorine, chloramines, coliforms and other indicator microorganisms. The formation of THMs was very low, on average below the 20.0 µg/L in all tests, apparently due to high concentrations of NH3-N, the order of 30.0 mg/L. The same did not occur with AHAs. In many tests found concentrations of AHAs exceeded the standard of 80.0 µg/L recommended by the USEPA for drinking water. Dechlorination reduced 52% of AHAs concentrations, in average. Bioassays showed that the presence of free chlorine in the samples increase the acute toxicity in Daphnia similes. Chlorination followed by dechlorination produces effluents with less toxicity than the toxicity of chlorinated and effluent without chlorination.

Chlorine as a disinfectant reacts with natural organic matter to produce undesired and possibly carcinogenic halogenated disinfection by-products (DBPs), which are regulated by the U.S. Environmental Protection Agency under the Disinfectant/Disinfection By-products Rule (DBPR). In order to comply with the increasingly stringent regulations, alternative disinfectants such as ozone, UV irradiation, and chloramines have been investigated. Unfortunately, these alternatives have their own limitations and disadvantages as well. Sonication is another alternative that has not yet received adequate research. The hydroxyl radicals, tensile stresses, and fluid shear generated during sonication may inactivate microorganisms. The goals of this research were to evaluate the effectiveness of sonication alone and combined sonication and chlorination for inactivation of E. coli. Four stages of disinfection experiments were conducted: chlorine alone, sonication alone, combined sonication and chlorination, and heating alone. Experiments were conducted in laboratory prepared phosphate buffered saline. The variables tested included the chlorine dose, chlorine contact time, sonication time, sonication system (probe or bath), sonication power-to-volume ratio, and sonication frequency. E. coli was enumerated by use of pour plates and/or membrane filtration before and after disinfection. Substantial temperature and turbidity increases were recorded after sonication, especially at 900 W/L. After 10 minutes of sonication at 900 W/L, the temperature and turbidity of the experimental solution rose up to 77oC and 23 NTU, respectively. At both 180 W/L and 900 W/L, sonication alone demonstrated little inactivation (less than 1 log10) of E. coli for temperatures below 60oC and greater than 7 log10 inactivation at temperatures over 60oC. The results from heating only experiments confirmed that temperature was responsible for the inactivation rather than other ultrasonic wave effects Sequential application of sonication and chlorination was ineffective at inactivating E. coli. Chlorination alone achieved higher levels of E. coli inactivation than the combination of both disinfectants. When sonication and chlorination were applied simultaneously, the inactivation was greater than the additive effect of two disinfectants, indicating that there were synergistic effects between sonication and chlorination. For example, at 900 W/L, chlorination alone at 0.6 mg/L for 2 minutes provided 1.2 log10 inactivation and sonication for 2 minutes alone provided less than 1 log10 inactivation of E. coli. When the two disinfectants were applied simultaneously, 4.5 log10 was achieved. Sonication may have weakened the cell membranes, causing them to be more susceptible to chlorine disinfection.

O aumento da incidência de florações de cianobactérias potencialmente tóxicas nos mananciais de abastecimento, favorecidas pelo elevado aporte de nutrientes nos corpos d\'água, compromete a qualidade da água de consumo e põe em risco a saúde humana e animal, além de elevar os custos do tratamento de água. A pré-cloração, tem se mostrado uma ótima opção tanto na inativação de cianobactérias como na remoção de cianotoxinas dissolvidas. No entanto, sob certas condições, pode causar lise celular e promover a liberação das toxinas no meio. O objetivo deste trabalho foi avaliar em escala laboratorial, o efeito da pré-cloração, utilizando como agente oxidante o hipoclorito de sódio, sobre a integridade celular de uma linhagem tóxica de Microcystis aeruginosa (LTPNA 08), por citometria de fluxo, e sobre a subsequente liberação e degradação das microcistinas (LR e RR) por LC-MS/ MS. Diferentes dosagens de cloro (0,05, 0,5, 1, 1,5, 2, 2,5, 3, 4 e 8 mg.L-1), tempos de contato (0, 15, 30 e 60 minutos) e densidade celular (1x106 células.mL-1 para os ensaios de jarros e 3,5 x106 células.mL-1 para o ensaio de viabilidade celular) foram utilizadas neste estudo. Os resultados obtidos nos ensaios de jarros mostraram remoções de microcistinas acima de 70% após 60 minutos de exposição ao oxidante, com 100% de remoção em doses de 2,5 e 3 mg Cl2.L-1. Valores de CT (concentração x tempo) acima de 40,66 mg.min.L-1 foram necessários para degradar as microcistinas a concentrações abaixo de 1,0 µg.L-1, exigidos pela organização mundial de saúde (WHO) e pela legislação brasileira de potabilidade da água (Portaria MS nº 2914/2011). Não foi possível verificar a lise celular por microscopia óptica, no entanto, na análise por HPLC-DAD verificou-se degradação de mais de 70% da clorofila-a em todas as dosagens testadas, após 60 minutos de exposição, com a completa degradação nas concentrações de 2,5 e 3 mg.L-1 Cl2, indicando dano celular. Nos ensaios por citometria de fluxo, foi verificada a perda da integridade celular com o aumento da dosagem de cloro aplicada, observando-se a permeabilidade celular máxima, sem a desintegração da célula, na concentração de 2,5 mg.L-1 Cl2. Concentrações de 4 e 8 mg.L1 Cl2 promoveram a lise total das células, impossibilitando a permanência do marcador na célula. A perda dos pigmentos clorofila a e ficocianina ocorreram em concentrações de acima de 2,5 e acima de 1,5 mg.L-1 Cl2, respectivamente. O presente trabalho reforçou a eficiência da cloração na degradação das toxinas e os resultados obtidos podem ajudar as autoridades competentes a otimizar as práticas de cloração utilizadas no pré-tratamento da água. / The increased incidence of blooms of potentially toxic cyanobacteria in supply sources, favored by high input of nutrients in water bodies, compromises the quality of drinking water and affect human and animal health, besides increasing water treatment costs. The pre-chlorination, has proved a great choice both in the inactivation of cyanobacterial cells as in removing dissolved cyanotoxins. However, under certain conditions, can cause cell lysis and release toxins. The objective of this study was to evaluate in laboratory scale, the effect of pre-chlorination, using sodium hypochlorite, on cell integrity of toxic Microcystis aeruginosa (LTPNA 08) using flow cytometry, and the subsequent release and degradation of microcystins (LR and RR) by LC-MS / MS. Different chlorine doses (0.05, 0.5, 1, 1.5, 2, 2.5, 3, 4 and 8 mg.L-1), contact times (0, 15, 30 and 60 minutes) and cell density (1x106 células.mL-1 for jar-test and 3.5 x106 células.mL-1 for cell viability assay) were used in this study. The results obtained in the jar- test showed degradations up to 70% after 60 minutes of exposure, with complete degradation at chlorine doses of 2,5 e 3 mg.L-1. Chlorine exposure (CT) values over 40,66 mg.min.L-1 were required for oxidation of microcystin LR and RR to concentrations below the World Health Organization (WHO) and Brazilian legislation for water potability (Portaria MS nº 2914/2011) guideline value of 1µg.L-1. No differences in cell number was observed by microscopy, however, analysis by HPLC-DAD found chlorophyll-a reductions of more than 70% in all dosages tested after 60 minutes exposure, with values below the limit of quantification for concentrations of 2.5 and 3 mg.L-1 Cl2, indicating cell damage. In assays using flow cytometry, loss of cell integrity was observed with increasing chlorine concentration. The maximum cell permeability without cell disintegration was observed at a concentration of 2.5 mg.L-1 Cl2. Concentrations of 4 and 8 mg.L-1 Cl2 lead to complete cell lysis, making impossible the permanence of SYTOX Green in the cell. The loss of pigment chlorophyll a and phycocyanin occurred in concentrations above 2.5 and 1.5 mg.L-1 Cl2, respectively. This study reinforced the efficiency of chlorination in the toxins degradation and the results can help the water authorities to optimize the chlorination practices used in the pretreatment of water.

Typescript. / Digitized by Kansas Correctional Industries

For bioactive chemical classes, it is often assumed that environmental transformation eliminates associated ecosystem risks. However, for endocrine-active steroid hormones, modest changes in structure can have a significant influence on biological activity and thus, subtle environmental transformations can yield products with conserved, enhanced, or activity across different biological endpoints. The aim of this work was to explore the environmental fate of high potency, endocrine-active steroid hormones during natural or engineered water processes in order to test the hypothesis that steroid transformation products generated during these processes are likely to contribute to residual bioactivity often reported in water resources. Specifically, laboratory experiments were used to simulate chemical disinfection (e.g., chlorination) or natural processes (e.g., photolysis) to: (i) determine the rate and extent of steroid transformation, (ii) isolate and identify products that are formed, and (iii) evaluate products or product mixtures for biological activity. These experimental results can be used to help guide occurrence studies for any products of concern in the environment and also guide computational predictions or rationalizations of chemical reactivity. Ultimately, the goal is to expand upon our awareness and understanding of how these potent endocrine ligands behave in the environment and how they potentially affect ecosystem health. Chapter 2 discusses the reaction of glucocorticoids (GC)s with aqueous chlorine (effectively, HOCl) to simulate their fate during engineered drinking water and wastewater chemical disinfection. Numerous transformation pathways were unveiled, including interconversion of GCs (e.g., endogenous cortisol to synthetic prednisolone), production of known androgens in the adrenosterone class, and chlorination of GCs (e.g., formation of 9-chloro-prednisone). We also showed that other advanced processes (e.g., oxidation via ozonation) result in more complete degradation of such pollutants, and may be better alternatives to chemical disinfection at eliminating bioactive steroidal product formation. In Chapter 3, results of the direct photolysis of dienogest (DNG), a widely prescribed oral contraceptive agent, are presented to simulate its fate in natural sunlit surface waters and engineered photochemical treatment systems (e.g., UV disinfection systems). The major products (~ 80% of the converted mass in neutral aqueous solutions) were identified to be photohydrates resulting from photochemical-induced incorporation of water into parent DNG. These products were found to be prone to dehydration in the dark, and thus, a source of substantial DNG regeneration (~ 65% after 72 h in neutral solutions). Other minor, non-revertible products were also identified, including two known estrogens. Although minor in initial yield, these estrogens are likely to accumulate over time through repeated cycling between DNG and its photohydrates, and thus, dominate DNG long-term fate. It was also found that DNG undergoes an unusual photochemical rearrangement to produce a minor product with a novel tetracyclic ring system--the subject of Chapter 4. Further, the generality of this unique photorearrangement process was explored through extension to the photolysis of two other dienone pharmaceutical steroids (e.g., the androgens methyldienolone and dienedione). Surprisingly, despite the significant change in core steroidal structure, the rearrangement products retain some progesterone receptor (PR) and androgen receptor (AR) bioactivity (i.e., low-µM to sub-nm EC50 values). Again, these represent other non-revertible, minor products that are likely to accumulate over time, with likely adverse ecological consequences. Chapter 5 covers results arising from the direct photolysis of trenbolone acetate (TBA) metabolites in the presence of model nucleophiles (e.g., sodium azide, sodium thiosulfate, ammonium hydroxide, hydroxylamine, and humic acid), some of which would be expected to be present, along with TBA metabolites, in agriculturally-impacted water resources. Previous studies by our group revealed that TBA metabolites undergo photohydration-thermal dehydration cycling, like that described above for DNG photolysis. The objective of this study was to determine if other nucleophiles would outcompete water for photochemical incorporation across the TBA metabolite extended conjugation system. It was found that TBA metabolite photolysis results in photochemical (and at times thermal) addition of the nucleophile to the TBA metabolites. It was also found that the addition products undergo thermal elimination in the dark and contribute to TBA metabolite regeneration, and therefore, are expected to increase TBA metabolite persistence in water resources. Finally, Chapter 6 discusses the reactions of various trienone and dienone steroids with aqueous chlorine to simulate their fate during engineered drinking water and wastewater chemical disinfection. Single-step transformation pathways were unveiled for each steroid class, including 4-chlorination (trienones) and 9,10-epoxidation (dienones). Chlorination at position C-4 is known to enhance anabolic potency of androgenic steroids and the 9,10-epoxy products were found to undergo acid- or base-catalyzed ring-opening and aromatization to yield known estrogenic products. In addition, Chapter 7 provides conclusions and future directions, while Chapter 8 details the experimental methods and procedures used throughout this thesis. Collectively, the results presented herein confirm our overall hypothesis that steroid transformation products would be expected to contribute to residual biological activity often detected in water resources. Furthermore, the results indicate that the transformation of high potency pharmaceuticals does not automatically equate with reduction or elimination of hazards to exposed organisms, especially in cases where such compounds have potential to form products exhibiting diverse biological endpoints. More holistic approaches to risk assessment of such high potency environmental contaminants are needed in order to accurately assess the fate and effects of such emerging pollutant classes and their bioactive transformation products.

Neonicotinoid insecticides are widespread in surface waters across the agriculturally-intensive Midwestern US. We report for the first time the presence of three neonicotinoids in finished drinking water and demonstrate their general persistence during conventional water treatment. Periodic tap water grab samples were collected at the University of Iowa over seven weeks in 2016 (May-July) after maize/soy planting. Clothianidin, imidacloprid, and thiamethoxam were ubiquitously detected in finished water samples and ranged from 0.24-57.3 ng/L. Samples collected along the University of Iowa treatment train indicate no apparent removal of clothianidin and imidacloprid, with modest thiamethoxam removal (~50%). In contrast, the concentrations of all neonicotinoids were substantially lower in the Iowa City treatment facility finished water using granular activated carbon (GAC) filtration. Batch experiments investigated potential losses. Thiamethoxam losses are due to base-catalyzed hydrolysis at high pH conditions during lime softening. GAC rapidly and nearly completely removed all three neonicotinoids. Clothianidin, hydrolysis products of thiamethoxam and known metabolites of imidacloprid are susceptible to reaction with free chlorine and may undergo transformation during chemical disinfection via chlorination or during distribution with chlorine residual. We identify several transformation products resulting from these oxidation and hydrolysis reactions, and discuss implications for human health. Our work provides new insights into the persistence of neonicotinoids and their potential for transformation during water treatment and distribution, while also identifying GAC as a potentially effective management tool to lower neonicotinoid concentrations in finished drinking water.