Florações de cianobactérias são facilmente encontradas, devido ao crescente aporte de nutrientes nos corpos de águas naturais e artificiais, ocasionado pelos acelerados processos de eutrofização frutos da ocupação urbana e rural sem a observação de critérios mínimos. Microcystis aeruginosa é uma espécie de cianobactéria potencialmente produtora de cianotoxinas, comumente associada a casos de intoxicação em escala mundial. Novas tecnologias para o tratamento de água têm sido implementadas para cumprimento dos padrões de potabilidade exigidos pela legislação. O presente trabalho buscou analisar a produção científica mundial relacionada ao tratamento de água com presença de M.aeruginosa e MCLR, buscando identificar o estado da arte, além de embasar a discussão dos métodos propostos. O presente estudo está dividido em três artigos, no primeiro realizou-se uma análise bibliométrica das pesquisas mundiais relacionadas à cianobactérias, cianotoxinas e o tratamento de água, a partir da base de dados Scopus. No segundo artigo buscou-se avaliar a aplicabilidade dos AOPs UV-C e UV-C/H2O2 na degradação de Microcystis aeruginosa BB005 e MC-LR, e a análise dos efeitos da adição de nanopartículas de Ag, com base em um produto comercial composto por peróxido de hidrogênio (H2O2) e nanopartículas de prata (NAg). No terceiro artigo buscou-se avaliar a qualidade da água produzida a partir de ensaios de toxicidade aguda com Daphnia magna. Os resultados indicam que a fotólise e o processo UV-C/H2O2 apresentaram resultados satisfatórios, sendo uma alternativa eficiente. Porém, os resultados dos ensaios de ecotoxicidade inferem que estes tratamentos utilizados com a finalidade de degradar M. aeruginosa e MC-LR, possuem potencial de geração de subprodutos de degradação tóxicos: os ensaios com D. magna demonstraram toxicidade mesmo quando a água submetida a fotólise foi diluída quatro vezes. Com relação ao processo UV-C/H2O2 (sem e com adição de NAg), a amostra foi tóxica quando não diluída. Já quando empregada as NAg combinadas a radiação UV-C, esta apresentou toxicidade extremamente alta, afetando a mobilidade de todos os organismos teste em todas as diluições (até 16 x). / Cyanobacterial blooms are easily found, due to the increasing nutrient supply in natural and artificial bodies of water, caused by the accelerated processes of eutrophication, fruits of urban and rural occupation without observing minimum criteria. Microcystis aeruginosa is a specie of cyanobacteria that are potentially cyanotoxin-producing, commonly associated with cases of worldwide intoxication. New technologies for water treatment have been implemented to meet the standards of potability required by legislation. The present study looked for analyze the world scientific production related to the treatment of water with presence of M. aeruginosa and MC-LR, seeking to identify the state of the art, besides supporting the discussion of the proposed methods. The present study is divided into three articles, the first one was a bibliometric analysis of the world-wide research related to cyanobacteria, cyanotoxins and water treatment, from the Scopus database. In the second article evaluated the aplicability of UV-C e UV-C/H2O2 AOPs on degradation of Microcystis aeruginosa BB005 and MC-LR, and the analysis of effects Ag nanoparticles addition, based on a commercial product composed of hydrogen peroxide (H2O2) and silver nanoparticles (NAg). In the trird article evaluated the water quality produced, from acute toxicity tests with Daphnia magna. The results indicate that photolysis and the UV-C/H2O2 process presents satisfactory results, being an efficient alternative. However, the results of the ecotoxicity assays infer that these treatments used for the purpose of degrading M. aeruginosa and MCLR, have potential to generate toxic degradation byproducts: the D. magna assays demonstrated toxicity even when the water submitted to photolysis was diluted four times. Regarding the UV-C/H2O2 process (without and with NAg addition), the sample was toxic when undiluted. When NAg was used in combination with UV-C radiation, it showed extremely high toxicity, affecting the mobility of all test organisms at all dilutions (until 16x).

Freshwater resources and supplies in South Africa are experiencing severe stress from rising population growth, drought and high urbanization. The stress factors have also exerted pressure on wastewater treatment works leading to the release of partially treated effluent. The study assessed and compared the impact of the two wastewater treatment works effluent discharged into the Roodeplaat Dam. Selected physical parameters (pH, conductivity), chemical parameters (total oxidised nitrogen, phosphate, chemical oxygen demand, chloride, sulphate, sodium) and microbiological parameter (Escherichia coli) were evaluated and compared with South African standards. Secondary data (from January 2012 to December 2017) was used to identify parameters that were above or below regulatory standards. The t-test (p < 0.05) was used to compare changes between 2012 and 2018 over the same months.The results indicated that aquatic ecosystem quality has not improved, degradation continues as well as a lack of intervention from authorities. The leading parameters in causing stress to Roodeplaat water quality in descending order were Escherichia coli (E. coli), Phosphate (PO43-), Total Oxidized Nitrogen (TON), Chemical Oxygen Demand (COD), Chlorophyll a (Chl a), Ammonia (NH3), Electrical Conductivity (EC) and Sodium (Na). One of the main reasons why poor effluent was released is limited financial investment to upgrade the treatment facilities. This research provided highlights on the need to enforce extra measures to guarantee compliance of treated effluent quality to the existing guidelines. Moreover it highlights the need for concerned department’s authorities to invest in water by allocating enough budget to address the challenge of wastewater treatment works upgrades. / Environmental Sciences / M. Sc. (Environmental Sciences)

Les proliférations nuisibles de la cyanobactérie filamenteuse benthique Lyngbya wollei qui forme des tapis déposés sur les sédiments ont augmenté en fréquence au cours des 30 dernières années dans les rivières, lacs et sources de l'Amérique du Nord. Lyngbya wollei produit des neurotoxines et des composés organiques volatils (géosmin, 2-méthylisobornéol) qui ont des répercussions sur la santé publique de même que des impacts d'ordre socioéconomiques. Cette cyanobactérie est considérée comme un habitat et une source de nourriture de piètre qualité pour les invertébrés en raison de sa gaine robuste et de sa production de toxines. Les proliférations de L. wollei ont été observées pour la première fois en 2005 dans le fleuve Saint-Laurent (SLR; Québec, Canada). Nous avons jugé important de déterminer sa distribution sur un tronçon de 250 km afin d'élaborer des modèles prédictifs de sa présence et biomasse en se basant sur les caractéristiques chimiques et physiques de l'eau. Lyngbya wollei était généralement observé en aval de la confluence de petits tributaires qui irriguent des terres agricoles. L’écoulement d’eaux enrichies à travers la végétation submergée se traduisait par une diminution de la concentration d’azote inorganique dissous (DIN), alors que les concentrations de carbone organique dissous (DOC) et de phosphore total dissous (TDP) demeuraient élevées, produisant un faible rapport DIN :TDP. Selon nos modèles, DOC (effet positif), TP (effet négatif) et DIN :TDP (effet négatif) sont les variables les plus importantes pour expliquer la répartition de cette cyanobactérie. La probabilité que L. wollei soit présent dans le SLR a été prédite avec exactitude dans 72 % à 92 % des cas pour un ensemble de données indépendantes. Nous avons ensuite examiné si les conditions hydrodynamiques, c'est-à-dire le courant généré par les vagues et l'écoulement du fleuve, contrôlent les variations spatiales et temporelles de biomasse de L. wollei dans un grand système fluvial. Nous avons mesuré la biomasse de L. wollei ainsi que les variables chimiques, physiques et météorologiques durant trois ans à 10 sites le long d'un gradient d'exposition au courant et au vent dans un grand (148 km2) lac fluvial du SLR. L'exposition aux vagues et la vitesse du courant contrôlaient les variations de biomasses spatiales et temporelles. La biomasse augmentait de mai à novembre et persistait durant l'hiver. Les variations interannuelles étaient contrôlées par l'écoulement de la rivière (niveau d'eau) avec la crue printanière qui délogeait les tapis de l'année précédente. Les baisses du niveau d'eau et l'augmentation de l'intensité des tempêtes anticipées par les scénarios de changements climatiques pourraient accroître la superficie colonisée par L. wollei de même que son accumulation sur les berges. Par la suite, nous avons évalué l'importance relative de L. wollei par rapport aux macrophytes et aux épiphytes. Nous avons examiné l'influence structurante de l'échelle spatiale sur les variables environnementales et la biomasse de ces producteurs primaires (PP) benthiques. Nous avons testé si leur biomasse reflétait la nature des agrégats d'habitat basées sur l'écogéomorphologie ou plutôt le continuum fluvial. Pour répondre à ces deux questions, nous avons utilisé un design à 3 échelles spatiales dans le SLR: 1) le long d'un tronçon de 250 km, 2) entre les lacs fluviaux localisés dans ce tronçon, 3) à l'intérieur de chaque lac fluvial. Les facteurs environnementaux (conductivité et TP) et la structure spatiale expliquent 59% de la variation de biomasse des trois PP benthiques. Spécifiquement, les variations de biomasses étaient le mieux expliquées par la conductivité (+) pour les macrophytes, par le ratio DIN:TDP (+) et le coefficient d'extinction lumineuse (+) pour les épiphytes et par le DOC (+) et le NH4+ (-) pour L. wollei. La structure spatiale à l'intérieur des lacs fluviaux était la plus importante composante spatiale pour tous les PP benthiques, suggérant que les effets locaux tels que l'enrichissement par les tributaire plutôt que les gradients amont-aval déterminent la biomasse de PP benthiques. Donc, la dynamique des agrégats d'habitat représente un cadre général adéquat pour expliquer les variations spatiales et la grande variété de conditions environnementales supportant des organismes aquatiques dans les grands fleuves. Enfin, nous avons étudié le rôle écologique des tapis de L. wollei dans les écosystèmes aquatiques, en particulier comme source de nourriture et refuge pour l'amphipode Gammarus fasciatus. Nous avons offert aux amphipodes un choix entre des tapis de L. wollei et soit des chlorophytes filamenteuses ou un tapis artificiel de laine acrylique lors d'expériences en laboratoire. Nous avons aussi reconstitué la diète in situ des amphipodes à l'aide du mixing model (d13C et δ15N). Gammarus fasciatus choisissait le substrat offrant le meilleur refuge face à la lumière (Acrylique>Lyngbya=Rhizoclonium>Spirogyra). La présence de saxitoxines, la composition élémentaire des tissus et l'abondance des épiphytes n'ont eu aucun effet sur le choix de substrat. Lyngbya wollei et ses épiphytes constituaient 36 et 24 % de l'alimentation in situ de G. fasciatus alors que les chlorophytes, les macrophytes et les épiphytes associées représentaient une fraction moins importante de son alimentation. Les tapis de cyanobactéries benthiques devraient être considérés comme un bon refuge et une source de nourriture pour les petits invertébrés omnivores tels que les amphipodes. / Harmful proliferations of the filamentous cyanobacterium L. wollei forming conspicuous benthic mats on the bottom sediment have been reported with increasing frequency in the last 30 years in rivers, lakes, and springs in North America. It is a known producer of neurotoxins and volatile organic compounds (geosmin, 2-methylisoborneol) thus exerting socioeconomic and public health impacts. Lyngbya wollei is also considered a poor nutritional source for invertebrates because of its robust sheath and toxin production. Proliferation of L. wollei in St. Lawrence River (SLR; Quebec, Canada) was first noticed in 2005. We deemed important to determine its distribution over a 250 km stretch of the SLR to elaborate predictive models of its presence and biomass based on chemical and physical characteristics. Lyngbya wollei was generally found downstream of the inflow tributaries draining farmlands. As enriched waters flowed slowly through submerged vegetation, dissolved inorganic nitrogen (DIN) concentration dropped but dissolved organic carbon (DOC) and total dissolved phosphorus (TDP) remained high, leading to a low DIN:TDP ratio. Models identified DOC (positive effect), TP (negative effect), and DIN:TDP (negative effect) as the most important variables explaining L. wollei distribution. The risk of L. wollei occurrence in the SLR was correctly forecasted in 72%-92% of all cases with an independent data set. We then examined if hydrodynamic conditions, namely currents generated by waves and river flow, control spatial and temporal variations of L. wollei biomass in a large river system. We measured L. wollei biomass together with meteorological, physical, and chemical variables over three years at 10 sites along a gradient of exposure to current and wind in a large (148 km2) fluvial lake of SLR. Wave exposure and current velocity controlled spatial and temporal biomass variations. Biomass increased from May to November and persisted during winter. Interannual variations were primarily controlled by river flow (water level) with spring discharge dislodging mats from the previous year. As anticipated under climate change scenarios, drops in water level and rising storm intensity may lead to an increase in the areas colonized by L. wollei, together with more frequent episodes of mat disruption and beach fouling. Additionally, we evaluated the relative importance of L. wollei with respect to macrophytes and epiphytes. We assessed the influence of the spatial scale in structuring environmental variables and biomass of these benthic primary producers (PP). We also test to which extent their biomass reflected the nature of patches based on ecogeomorphology or the river continuum. To address these two questions, we used a nested design at 3 spatial scales within the SLR: 1) along a 250-km-long upstream-downstream river stretch, 2) among three fluvial lakes located within that river stretch and 3) within each fluvial lake. Environmental factors (conductivity and TP) and spatial structure together explained 59% of the variability in biomass of all three benthic PP. Spatial variability of biomass was best explained by conductivity (+) for macrophytes, DIN:TDP ratio (+) and water extinction coefficient (+) for epiphytes and DOC (+) and NH4+ (-) for L. wollei mats. Within-lake structure was the most important spatial component for all benthic PP, suggesting that local effects, such as enrichment by the inflow of tributaries, rather than upstream-downstream gradients, determined the biomass and composition of benthic PP. Therefore patch dynamics represents a general framework which adequately covers the spatial variability and wide variety of environmental conditions experienced by aquatic organisms found in large rivers. Finally, we investigated the ecological role of L. wollei mats in aquatic ecosystems, especially as a food source and shelter for the amphipod Gammarus fasciatus. We offered amphipods a choice between mats of L. wollei and either chlorophytes or an artificial mat made of acrylic wool in laboratory experiment. Moreover, we reconstructed in situ amphipod diet using mixing model (δ13C and δ15N). Gammarus fasciatus selected the substratum offering the best light refuge (Acrylic > Lyngbya = Rhizoclonium > Spirogyra). Presence of saxitoxins, tissue elemental composition and epiphyte abundance had no significant effect on substratum choice. Lyngbya wollei and its epiphytes constituted 36 and 24% of the in situ diet of G. fasciatus whereas chlorophytes, macrophytes and associated epiphytes represented a less important fraction of its diet. Benthic cyanobacterial mats should be considered a good shelter and food source for small omnivorous invertebrates such as amphipods.

CAPES; CNPq / Considerada como o maior complexo hídrico do Paraná, a Bacia do Iguaçu tem importância estratégica, principalmente no que se refere à característica do rio – por sua extensão e potencial hidrelétrico altamente explorado – com a formação de cinco reservatórios para gerar mais de 6.000 MW de energia. Em detrimento de sua importância estratégica, o represamento em cascada do Rio Iguaçu faz com que suas características hidráulicas sejam modificadas, podendo gerar passivos ambientais, como a incidência de florações de cianobactérias nos reservatórios, podendo apresentar potencial tóxico. São poucos estudos que contemplem a bacia do Iguaçu como um todo, avaliando o rio e os reservatórios formadores desse importante complexo hidrográfico. Pautado nesse entendimento, este estudo tem como objetivo avaliar a relação entre a qualidade da água na Bacia do Rio Iguaçu e a influência na ocorrência e concentração da cianotoxina microcistina-LR nos seus reservatórios. Com esta finalidade, foram realizadas três coletas de amostras de água no Rio Iguaçu da sua nascente na Região Metropolitana de Curitiba até sua foz, em Foz do Iguaçu. Também foram realizadas amostragens em quatro dos cinco reservatórios grandes reservatórios da Bacia: Foz do Areia, Segredo, Salto Santiago e Salto Caxias e avaliado variáveis físicas e químicas, teor e fonte de matéria orgânica e a contaminação nos reservatórios pela cianotoxina microcistina-LR na água. A avaliação dos resultados obtidos possibilitou a observação das principais influências no Rio Iguaçu, tais como atividade antrópica na Região Metropolitana de Curitiba, sazonalidade, e a influencia da mudança hidráulica promovida pelos reservatórios. Nos reservatórios estudados, as principais variáveis estão relacionadas com a sazonalidade, tempo de retenção hidráulico, nutrientes e produtividade primária. A Microcistina-LR foi detectada nos reservatórios de Foz do Areia, Segredo e Salto Santiago, este ultimo com a maior concentração de toxina intracelular obtida no centro da região lacustre, com concentração de 18,62 μg por litro filtrado e Foz do Areia, com 65,5 μg por litro filtrado em um ponto de margem com alta concentração de clorofila-a. As analises estatísticas permitiram a compreensão das variáveis possivelmente responsáveis pelo aumento da biomassa fitoplantônica, porém, não foi possível obter relações significativas que pudessem explicar a produção da microcistina intracelular. Diante dos resultados observados, fazem-se necessárias políticas de maior controle ambiental, visando à melhoria no tratamento de efluentes e uso e ocupação do solo em toda a extensão da bacia hidrográfica, porém, mais urgentemente na região do Alto Iguaçu. / Considered the largest hydric complex in Paraná, the basin Iguaçu has strategic importance, especially regarding the characteristics of the river, by its great extension and the highly exploited hydropower, forming five reservoirs that generate more than 6.000 MW energy. In detriment of its strategic significance, the damming of the Iguassu River modifies the hydraulic characteristics, which may cause some environmental damage, as the incidence of cyanobacterial blooms in reservoirs may submit toxic potential. Are few studies that consider the Iguaçu basin as a whole, evaluating the river and reservoirs forming this important hydrographic complex. Guided by this understanding, this study aims to evaluate the relationship between water quality in the Rio Iguaçu basin and the influence on the occurrence and concentration of microcystin-LR in its reservoirs. For this purpose, three collections of sampling were performed in Iguazu River from its source in the Metropolitan Region of Curitiba to its mouth in Foz do Iguaçu. Samples in four of the five major reservoirs Basin reservoirs were also performed: Foz do Areia, Segredo, Salto and Salto Caxias Santiago and evaluated physical and chemical variables, content and source of organic matter in reservoirs and contamination by microcystin-LR cyanotoxin. Furthermore, in the reservoirs was evaluated the possibility of contamination by cyanotoxin microcystin-LR. The results evaluation enabled the observation of the main influences on the Iguaçu River, such as anthropogenic influences in Curitiba Metropolitan Region, seasonality, and the influence of change promoted by the hydraulic reservoirs. In the studied reservoirs, the main variables are related to hydraulic seasonal retention time, nutrients and primary productivity. The microcystin- LR was detected in the reservoirs of Foz do Areia, Segredo and Salto Santiago, the latter with the highest concentration of intracellular toxin in the center of the lake region, with a concentration of 18.62μg per liter filtered and Foz do Areia, 65μg, on a point margin with a high concentration of chlorophyll-a. The statistical analysis allowed to understand the variables as possibly responsible for increasing phytoplankton biomass, however, it was not possible to obtain significant relations which could explain the production of intracellular microcystin. Front of the observed outcomes, this study points to the need of policies to increase environmental control, aiming to improve in wastewater treatment and the ground use and occupation all along the basin, but more urgently in the Alto Iguaçu.

MESHWR / Department of Hydrology and Water Resources / In South Africa, inland aquaculture is on the increase, especially among the rural communities. Thus aquaculture is able to provide a source of employment and improve rural incomes. This study assessed algae species and their cyanotoxins in small holder production in Vhembe district, Limpopo, South Africa. Thirteen study sites were selected to assess the algae species and their cyanotoxins. The water samples were collected in four quarters and analysed for water temperature, pH, total dissolved solids, Electrical conductivity, phosphates, nitrates, chlorophyll, cyanobacteria, cyanotoxins, metal species and quality of the water in the fish ponds. In the 1st quarter of the year there was variation in Water Temperature (23.7oC-31.4oC), pH (5.5-9.6), EC (3.82-46.8μS/cm), TDS (2.4-45 mg/L), Phosphate (0.0-1.09mgL-1), Nitrates (0.0-1.00mgL-1), Chlorophyll-a (5.8-11.5mg/m-3). In the 2nd quarter there was variation inwater temperature (22.4-25.0oC), pH (6.6-8.8.9), EC (19.23-21.47μS/cm), TDS (12.5-17.9 mg/L), Phosphate (1.64-1.84mgL-1), Nitrates (1.02-1.88mgL-1), Chlorophyll-a (4.6-15.6mg/m-3). In the 3rd quarter there was variation for water temperature (22.9-25.0oC), pH (7.5-9.1), EC (7.91-293.3μS/cm), TDS (11.7-180.9 mg/L), Phosphate (1.10-1.80mgL-1), Nitrates (1.28-1.84mgL-1),Chlorophyll-a (6.8-15.6mg/m-3). In the 4th quarter there was variation forwater temperature (23.5-30.3), pH (7.1-9.3), EC (18.24-623μS/cm), TDS (23.7-136.4 mg/L), Phosphate (1.45-1.99mgL-1), Nitrates (1.43-1.68mgL-1), Chlorophyll-a (6.6-25.9mg/m-3). The metal content of the fish pond water was variable throughout the year but with moderate levels of Al, Cd, Cr, Mn, Fe, Cu, Zn and Ba were found. The metal Fe, exceeded the DWAF guideline values during this first quarter. The presence of Cd in the fish pond water could be attributed to rainfall eroding the earthen embankments of the fish pond. The results of physico-chemical parameters promotes the growth of cyanobacteria in the fish ponds. Flow cam and SEM were used to identify the cyanobacteria species and most cyanobacteria identified are hazard to human health, fish and other aquatic organisms. Molecular technologies were used to identify cyanotoxins and there was no cyanotoxins detected which was concluded that during collection of water samples no cyanobacteria produced toxins. / NRF

Indiana University-Purdue University Indianapolis (IUPUI) / In this research, Environmental Fluid Dynamic Code (EFDC) and Adaptive- Networkbased Fuzzy Inference System Models (ANFIS) were developed and implemented to determine the spatial-temporal distribution of cyanobacterial metabolites: 2-MIB and geosmin, in Eagle Creek Reservoir, IN. The research is based on the current need for understanding algae dynamics and developing prediction methods for algal taste and odor release events. In this research the methodology for prediction of 2-MIB and geosmin production was explored. The approach incorporated a combination of numerical and heuristic modeling to show its capabilities in prediction of cyanobacteria metabolites. The reservoir’s variable data measured at monitoring stations and consisting of chemical/physical and biological parameters with the addition of calculated mixing conditions within the reservoir were used to train and validate the models. The Adaptive – Network based Fuzzy Inference System performed satisfactorily in predicting the metabolites, in spite of multiple model constraints. The predictions followed the generally observed trends of algal metabolites during the three seasons over three years (2008-2010). The randomly selected data pairs for geosmin for validation achieved coefficient of determination of 0.78, while 2-MIB validation was not accepted due to large differences between two observations and their model prediction. Although, these ANFIS results were accepted, the further application of the ANFIS model coupled with the numerical models to predict spatio-temporal distribution of metabolites showed serious limitations, due to numerical model calibration errors. The EFDC-ANFIS model over-predicted Pseudanabaena spp. biovolumes for selected stations. The predicted value was 18,386,540 mm3/m3, while observed values were 942,478 mm3/m3. The model simulating Planktothrix agardhii gave negative biovolumes, which were assumed to represent zero values observed at the station. The taste and odor metabolite, geosmin, was under-predicted as the predicted v concentration was 3.43 ng/L in comparison to observed value of 11.35 ng/l. The 2-MIB model did not validate during EFDC to ANFIS model evaluation. The proposed approach and developed methodology could be used for future applications if the limitations are appropriately addressed.