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The work is focused on monitoring changes in benthic communities in the longitudinal gradient of the river Lužnice. The river flows through to the pond area Třeboňsko and the largest pond of the Czech Republic - Rožmberk. It is examine affect of pond on benthic communities. The work involves collecting benthos according to the PERLA method on four profile in four seasons, the analysis of chemical parameters and data processing. The values of SI (saprobiological index) in the longitudinal gradient were from SI 1.8 to SI 2.6. SI values were at the outflow of Rožmberk higher than at inflow. The lowest values were in the first profile Suchdol (SI 1,8 ? SI 2,1) and higher values were in the last profile Vlkov (SI 2,4 ? 2,6). The chemical parameters at outflow were observed increased values of BOD5, TOC, NL105, NL505, chlorophyll and total P but lower values of nitrogen forms (Ntotal,NH4, N-NO3-). On the each profile was the significant change in the incidence or absence of certain groups. Profiles Suchdol and Hlína were diferent than Lužnice and Vlkov especially in the presence of stoneflies, dragonflies, beetles, and individuals generally indicates good water quality. Profiles at outflows from Rožmberk (Lužnice and Vlkov) showed a continued presence of bloodsuckers and more species indicating high organic pollution. NMDS method confirmed impact of sites in communities rather than period (R2 = 0.6 at significance level of p = 0.001).

Lakes provide essential ecosystem services to humankind, with the provision of freshwater likely being their most important contribution to human well-being. Therefore, it is mandatory to prevent freshwater lakes from harm in order to protect our livelihood. Pollution is known to put the health of our planet at risk, including our aquatic ecosystems. For European lowland surface waters, certain key organisms, including algae, crustacea, and fish, have been shown to be impacted by chemical pollution. However, currently little is known about the influence on other key organisms (e.g. macrophyte communities) and the spatial extent of these impacts. To close these gaps in knowledge and generally develop a better understanding of the impact of chemical pollution on our aquatic environment, is key for its efficient protection and the preservation of its ecosystem services. This dissertation aims to close these knowledge gaps and thereby increase our understanding of the impact of organic chemicals on our aquatic environment. During the course of this dissertation, two field studies and one literature review were conducted. The first field study was performed in eight lowland lakes of Schleswig-Holstein. Goal was to demonstrate that contaminated sediments prevent macrophyte communities from reaching a good ecological state. It was possible to show that sediment toxicity, driven by antifouling biocides and polycyclic aromatic hydrocarbons, is one of the factors that limit the ecological quality macrophyte communities can reach. The second field study was performed in eight lakes of the French Pyrenees. In this case, the aim was to explore the exposure and risk for waterbodies as remote as mountain lakes by organic chemicals. It was found that also mountain lakes are exposed to a wide variety of organic chemicals, including substances introduced via the atmosphere and local sources. All lakes under investigation were experiencing a chronic toxic risk for crustacea and three of eight lakes were even exposed to an acute toxic risk for crustacea. As this risk was also reflected in lowered abundancies of crustacea, this demonstrated that also waterbodies as remote as mountain lakes are impacted by chemical pollution. Following up on these findings, a literature review was performed. While generally little investigated, the data that could be found support the idea that toxic effects on mountain lakes might be widespread. The results of this thesis add to the growing knowledge, indicating that chemical pollution is jeopardizing the ecological quality of our planet and thereby, causing it to become unhealthy and dysfunctional. To protect our aquatic ecosystems, and planetary heath in general, it will be necessary to reduce our emissions of organic chemicals and use of particularly toxic substances.

L’électrocoagulation est une technique de traitement des eaux usées basée sur la dissolution d’anode sacrificielle de fer ou d’aluminium. Ces métaux se dissolvent sous formes de cations Fe2+ puis Fe3+ et Al3+ qui vont former des hydroxydes de métal qui entraînent par adsorption les impuretés de l’effluent en diminuant le potentiel Zêta de ces impuretés. Le réacteur électrochimique utilisé est constitué de deux électrodes métalliques (Fe ou Al) planes et parallèles qui laissent passer entre elles l’effluent à traiter. Des densités de courant de 50 à 200 A/m2 ont été appliquées pour traiter les trois effluents. L’un est un effluent directement issu d’une usine textile (effluent « usine »). Un second provient du flux d’entrée de la station d’épuration du site qui collecte les effluents de plusieurs usines (effluent « station »). Le troisième est un effluent artificiel de tannerie, créé en ajoutant 200 ppm de chrome VI à l’effluent « station ». Pour chaque expérience, la densité de courant et le temps de traitement vont déterminer la charge électrique et la concentration en métal dissous atteinte. L’influence de ces quatre paramètres sur l’élimination de la DCO, de l’absorbance, de la turbidité, du COT et du chrome hexavalent a été étudiée. L’évolution au cours du temps d’autres paramètres de l’EC tels que le pH, la tension, le rendement faradique et la dissolution métallique ont été étudiés afin de comprendre leur rôle dans le procédé. Le traitement a permis d’avoir un abattement maximal de DCO de 82% et 80% pour l’effluent « station » traité respectivement avec les électrodes de fer et d’aluminium ; 75 et 67% pour l’effluent « usine » traité respectivement avec les électrodes de fer et d’aluminium. L’abattement du chrome est de 100% avec les électrodes de fer mais tombe à 70% avec celles en aluminium. Des modèles d’élimination de la DCO et de l’absorbance ont été établis pour chaque matériau d’électrode utilisé. Le modèle d’élimination du chrome VI a été établi à partir du traitement avec les électrodes de fer. Une étude de la spéciation des espèces a permis de déterminer les pH optimaux de coagulation-floculation pour chaque métal impliqué (Al, Fe, Cr). La compétitivité entre l’abattement de la pollution organique et du Chrome a aussi été étudiée pour chaque type d’électrode / Electrocoagulation (EC) is a water treatment technology that relies on the electrochemical sacrificial anodes (in Fe or Al) dissolution. This metal dissolve themselves in Al3+ and Fe2+ cations that later oxidise to Fe3+ ions. These cations form metal hydroxides that adsorb the impurities of the effluent while decreasing the zeta potential. The electrochemical reactor used consists on two plane parallel metal electrodes with recirculation of the effluent to be treated between them. Current densities from 50 to 200 A/m2 were imposed to treat each effluent. Three effluents were used in this study. The first one is an effluent sampled at the outlet of a textile plant (« plant »). The second one is a mixture of several effluents coming from different plant and collected at the inlet of the wastewater treatment (« treatment plant »). The last one is a wastewater tannery plant simulated by addition of 200 ppm Chromium VI in the treatment plant effluent. For each experience the current density and the time of treatment rule the electrical charge and the concentration in dissolved metal reached. The influence of these four parameters on the elimination of COD, absorbance, turbidity, COT and hexavalent chromium content has been studied. Parameters e.g. potential, faradic yield, metal dissolution and pH have also been continuously monitored to better understand their role on EC process. The results show that DCO abatement reached 80 and 82% for treatment plant effluent, respectively with iron and aluminium electrodes; and 75 and 67% for plant effluent, respectively with iron and aluminium electrodes. The chromium treatment yields 100 % abatement with Fe electrodes whereas it is only 70% using Al electrodes. Models have been developed for COD and absorbance removal for the two electrode materials. Model for chromium (VI) treatment has been established considering all reactions occurring for iron EC. Metal speciation study allowed us to determine the optimal pH of coagulation –flocculation for each metal involved in the treatment (Al, Fe, Cr). Competition between organic pollution removal and chromium elimination has been also investigated for each electrode material

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Adverse effects of the use of herbicides, such as toxicity to non-target species and production of persistent residues in soil and in surface water, have drawn attention and stimulated research to better understand the destination in the environment and to the development of efficient methods of decontamination. The Phytoremediation is a process based on the use of plants and their associated microbiota in order to extract, stabilize, metabolize, compartmentalize and / or degrade pollutants. In view of the exposured, this dissertation aimed to: 1) make a review on phytoremediation of soils contaminated with herbicides (Chapter I), 2) select plant species that show tolerance to the herbicide compound made by mixing Imazapic + imazethapyr (75 + 25 g e.a. L-1) to be tested for its phytoremediation efficiency (Chapter II), 3) evaluate the efficiency of plant species in the remediation of soil contaminated with the studied herbicide mixture, using the irrigated rice cultivar IRGA 417 as a bioindicator plant (Chapter III) and 4) evaluate the degradation of the herbicide compound formulated mixture of imazethapyr + Imazapic (75 + 25 g e.a. L- 1) in rhizosphere soil from the cultivation of Canavalia ensiformis, Glycine max, Lolium multiflorum, Lotus corniculatus, Stizolobium aterrimum and Vicia sativa (Chapter IV). The species espécies Avena strigosa, Lolium multiflorum, Secale cereale, Lotus corniculatus, Crotalaria juncea, Vicia sativa, Canavalia ensiformis, Stizolobium aterrimum, Glycine max and Raphanus sativus showed significant tolerance and phytoremediation potential, being efficient in descontaminating the soil with compost by the presence of the herbicide formulated mixture imazethapyr + Imazapic (75 + 25 g ai L-1). The highest metabolic activity, evidenced by the release of CO2 observed in soil vegetated with plant species Lutus corniculatus, Lolium multiflorum, Vicia sativa, Canavalia ensifromis, Stizolobium aterrimum and Glycine max, allows to infer that these species can influence the activity of the microbiota present in rhizosphere of the same, resulting in mineralization of the herbicides imazethapyr and Imazapic. / Os efeitos adversos da utilização de herbicidas como sua toxicidade para espécies não-alvo e produção de resíduos persistentes no solo e em águas superficiais, têm chamado a atenção e estimulado pesquisas para melhor compreensão do destino no ambiente e para o desenvolvimento de métodos eficientes de descontaminação. A fitorremediação é um processo baseado na utilização de plantas e sua microbiota associada com a finalidade de extrair, estabilizar, metabolizar, compartimentalizar e/ou degradar poluentes. Em vista do exposto, a presente dissertação de mestrado teve por objetivos: 1) fazer uma revisão de literatura sobre a fitorremediação de solos contaminados com herbicidas (Capítulo I); 2) selecionar espécies vegetais que apresentem tolerância à presença do herbicida composto pela mistura formulada de imazetapir + imazapique (75 + 25 g e.a. L-1) para serem testadas quanto sua eficiência fitorremediadora (Capítulo II); 3) avaliar a eficiência de espécies vegetais na remediação do solo contaminado com a mistura herbicida estudada, utilizando a cultivar de arroz irrigado IRGA 417 como planta bioindicadora (Capítulo III) e 4) avaliar a degradação do herbicida composto pela mistura formulada de imazetapir + imazapique (75 + 25 g e.a. L-1) em solo rizosférico proveniente do cultivo de Canavalia ensiformis, Glycine max, Lolium multiflorum, Lotus corniculatus, Stizolobium aterrimum e Vicia sativa (Capítulo IV). As espécies Avena strigosa, Lolium multiflorum, Lotus corniculatus, Crotalaria juncea, Vicia sativa, Canavalia ensiformis, Stizolobium aterrimum, Glycine max e Raphanus sativus apresentaram tolerância significativa e potencial fitorremediador, sendo eficientes na descontaminação do solo com presença do herbicida composto pela mistura formulada de imazetapir + imazapique (75 + 25 g e.a. L-1). A maior atividade metabólica, evidenciada pelo desprendimento de CO2, observada em solo vegetado com as espécies vegetais Lotus corniculatus, Lolium multiflorum, Vicia sativa, Canavalia ensiformis, Stizolobium aterrimum e Glycine max, permiti inferir que estas espécies podem influenciar a atividade da microbiota presente na rizosfera das mesmas, resultando na mineralização dos herbicidas imazetapir e imazapique.

La zone côtière Atlantique constitue une importante nourricerie pour les juvéniles de sole commune (Solea solea, Linnaeus 1758). Pour évaluer les conséquences sur la biologie des juvéniles de cette espèce exploitant un milieu côtier de plus en plus anthropisé, les effets de l’hypoxie et/ou des Polychlorobiphényles (PCBs) ont été évalués sur leurs performances physiologiques (métabolisme aérobie et performances cardiaques) ainsi que sur leur comportement vis-à-vis des prédateurs. Pour cela, une étude a été réalisée à deux échelles d’organisation biologique, l’organe et l’individu. Des contaminations aux PCBs (670 ng and 2239 ng PCB g-1 de nourriture ont été effectuées expérimentalement par voie trophique pendant 30 et 60 jours. De telles expositions ont engendré des effets peu marqués sur le métabolisme aérobie, se traduisant par une faible augmentation du métabolisme de maintenance associé à une augmentation de la concentration critique en oxygène (O2crit) chez les soles exposées sur le long terme à la plus haute concentration de PCB. De la même façon, la performance cardiaque n’est apparue que très peu affectée par la contamination aux PCBs. Nous avons tout de même noté une diminution de la force de contraction du cœur des soles contaminées lorsqu’il est fortement sollicité comme c’est le cas au cours d’une activité physique soutenue. Par ailleurs, le mécanisme de contraction du cœur se trouve modifié chez les soles contaminées avec une participation plus importante du calcium issu du réticulum sarcoplasmique que chez les soles témoins. Les résultats concernant le comportement anti-prédateur ont montré que l’hypoxie engendrait une réduction du taux de réponse de fuite de la sole, ainsi qu’une limitation de leur capacité cryptique via une augmentation oxy-dépendent de la fréquence de ventilation. D’une façon générale, même si les PCBs semblent avoir peu d’effets sur les performances physiologiques testées, il ne peut être exclu qu’ils puissent compromettre à plus long terme le développement et la survie des juvéniles de soles, qu’ils soient associés ou non à des conditions environnementales limitantes comme l’hypoxie. / The Atlantic coastal zone constitutes an important nursery for the juveniles of the common sole (Solea solea, Linnaeus on 1758). To assess the effect of anthropisation on the survival of the juveniles of common sole, the effects of the hypoxia and\or Polychlorinated Biphenyles (PCBs) on their physiological performances (aerobic metabolism and cardiac performances) were assessed as well as their antipredator behaviour. For that purpose, the study was carried out at two levels of biological organization, the organ and the individual. Sole contamination with PCB (670 ng and 2239 ng PCB g-1 of food), was made experimentally via the trophic pathway, during 30 and 60 days. Our results suggest that PCBs slightly affected the aerobic metabolism. An increase of the standard metabolic rate participate to raise the level of critical oxygen concentration (CritO2) in soles exposed to long term to the highest concentration of PCB was noted. In the same way, the cardiac performances seem to be slightly affected by PCB-contamination. A decrease in the peak tension was noted in PCB-contaminated soles forced to an intense activity. In addition it was noted an increase in the participation of the sarcoplasmic reticulum to the force of contraction in the hearts of soles contaminated compared with hearts of control soles. The results obtained with regard to the simulation of the attack of a predator showed that responsiveness was lower in hypoxia compared with normoxia associated with a decrease of their cryptic capacity. In general, even if the PCB seems to have slight effects on the tested physiological performances, it cannot be excluded that long term exposure to PCBs can compromise the development and the survival of the juveniles of common sole, independently of their association with limiting environmental conditions such as hypoxia.

This thesis is focused on technological processes during drinking water treatment. The emphasis is put on monitoring indicators of organic substances present in water and indicators of the biological stability of treated water. The experimental part is focused on the comparison of separation efficiency of drinking water treatment technological processes by monitoring of chemical oxygen demand, absorbance measured at 254 nm, bioseston, culturable microorganisms and assimilable organic carbon.

This diploma thesis focuses on possibilities of applications of UV radiation to remove pollutants from water. It summarizes sources of UV radiation and list their benefits and properties. The thesis characterizes so called advanced oxidation processes using UV light. Degradation pathways od pyridine and its derivatives especially halogenated pyridines are described. The photodegradability of pyridine and a rate of this reaction in model water is investigated in the experimental part. Also, the effect of concentration and dose of H2O2 is assessed. Gas chromatography was used to determinate concentrations of pyridine in samples.

This diploma thesis explores treatment options of wastewater with a low presence of organic pollution produced by minor pollution sources. The research part describes objects with a low presence of organic pollution in wastewater and possible treatment methods in dependence of pollution source's size. The practical part contains the design of technological options of treatment of wastewater with a low presence of organic pollution for a specific object.