Ce mémoire de thèse s'inscrit dans la problématique de l'Evaluation Des Risques Ecotoxicologiques (EDREcotox) liés aux rejets d'effluents hospitaliers dans les milieux aquatiques. Le premier objectif vise à améliorer la connaissance des effets écotoxicologiques des effluents hospitaliers. Pour cela, nous avons étudié d'une part, les effets combinés des principaux polluants contenus dans ces effluents vis-à-vis de Daphnia magna et, d'autre part, les effluents provenant d'un hôpital d'une grande ville française, en intégrant leur caractérisation physico-chimique et écotoxicologique approfondie. Nous avons alors mis en œuvre des EDREcotox basées sur les différentes approches préalablement étudiées (substances, substances avec effets combinés, bioessais mono-spécifiques et pluri-spécifiques). Le second objectif de ce travail vise à contribuer à l'amélioration des méthodologies de caractérisation des effets écotoxicologiques, à la fois d'un point de vue général et pour le scénario spécifique étudié : « rejets des effluents d'un hôpital d'une grande ville du Sud-Est de la France dans le réseau d'eaux usées en direction de la station d'épuration puis du cours d'eau ». Les résultats obtenus montrent que les effets combinés des mélanges de désinfectants/surfactants étudiés sont additifs vis-à-vis de D. magna. Quelle que soit l'approche utilisée, nos résultats révèlent la toxicité des effluents étudiés. Les EDREcotox montrent cependant que, dans le cas de notre scénario, le risque écotoxicologique est faible pour les organismes du milieu récepteur. Nos recherches ont également permis de proposer une méthodologie de caractérisation des effets écotoxicologiques basée sur une première étape constituée d'une approche intégrée. Enfin, ce travail permet d'aboutir à des recommandations pour une meilleure gestion des effluents hospitaliers.

Phosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.

Recent studies have shown that dehydroabietic acid (DHAA), a resin acid present in pulp and paper mills, may have anti-estrogenic effects in fish. A chronic-exposure toxicity experiment using immature rainbow trout (Oncorhynchus mykiss) was conducted in order to assess the endocrine disrupting and liver metabolic effects of the wood extractives DHAA and β- sitosterol (BS) regularly present in pulp and paper mills and the model estrogen 17β-estradiol (E2). It was found that exposure to 5 ppm of E2 significantly increased hepatosomatic index (HSI), vitellogenin (VTG) and plasma sorbitol dehydrogenase (SDH). This effect was reduced by mixing E2 with DHAA, indicating that DHAA does not cause its anti-estrogenic effects indirectly due to liver damage. Exposure to 5 ppm of DHAA caused a significant increase in liver citrate synthase (CS), and liver ethoxyresorufin-O-deethylase (EROD) activity after 7 days, however, the fish recovered by 28 days. This study also determined the effect of 14 different pulp and paper mill effluent extracts on liver enzyme metabolism through alterations in the activity of liver lactate dehydrogenase activity (LDH) and CS. This activity varied greatly between mills but most showed an induction of CS after 28 days exposure through i.p. injection. The results of the study indicate that DHAA may alter energy metabolism as well as cause anti-estrogenic effects in female juvenile rainbow trout. / UOIT

Previous studies on fishes exposed to effluent from the Key Lake uranium mill in northern Saskatchewan have demonstrated elevated lipids in young-of-the-year pike (Esox lucius), deformities in larval pike and decreased survival of fathead minnows (Pimephales promelas). The objectives of this thesis were to evaluate possible factors that could be contributing to altered bioenergetics of juvenile northern pike inhabiting lakes receiving effluent from the Key Lake operation and to examine the effects of effluent exposure on biomarkers of oxidative stress and histopathology of target organs. Although glycogen and triglycerides stores were significantly greater in pike from exposure lakes compared to the reference, triglycerides stores of juvenile pike prey items showed no overall differences among lakes. Measures of parasitism, however, were negatively correlated with pike bioenergetics thereby reflecting a possible energetic cost of parasitism on reference lake fish. The degree of infection by intestinal parasites and gill monogeneans was greatest in reference pike and intermediate in low exposure pike, whereas high exposure pike harboured no parasites. <p>Arsenic, nickel and selenium are elevated in lakes downstream of the Key Lake mill and have been shown to be associated with increased reactive oxygen species (ROS) in biological systems causing oxidative stress. The potential for oxidative stress was assessed in pike liver and kidney using several biomarkers. Overall, the concentrations of total, reduced and oxidized glutathione and the ratio of oxidized to reduced glutathione did not differ significantly among exposure and reference pike. The activity of glutathione peroxidase was greater in high exposure than reference liver whereas, contrary to predictions, lipid peroxidation was greater in reference than exposure pike tissues. <p>Histopathological evaluations revealed greater kidney and gill pathology in reference lake pike, whereas for liver, hepatocyte morphology differed among lakes without any clear signs of pathology. Trace metal analyses of muscle showed that eight elements (arsenic, cobalt, copper, iron, molybdenum, selenium, thallium, uranium) were significantly elevated in exposure pike. These results provide only limited evidence of oxidative stress in exposure pike tissues and no evidence of histopathology despite indications that metals are bioaccumulating in tissue. Overall, the results from this thesis suggest that the health and condition of juvenile northern pike living downstream of the Key Lake uranium mill may not be compromised by effluent exposure.

Municipal wastewater effluent (MWWE) is an important source of pollution in the aquatic environment impacting fish. MWWE is a complex mixture of chemicals including pharmaceuticals, personal care products, industrial chemicals and pesticides. A link between reproductive endocrine disruption and MWWE exposure has been established in fish, but less is known about the effects of MWWE on non-reproductive endocrine disruption. The overall objective of this thesis was to examine the impacts of MWWE exposure on the stress response and intermediary metabolism in rainbow trout (Oncorhynchus mykiss). In fish, the primary adaptive organismal stress response involves the activation of hypothalamic-sympathetic-chromaffin axis to produce catecholamines, predominantly epinephrine, and the hypothalamic-pituitary-interrenal (HPI) axis to produce cortisol. Both of these hormones play a key role in elevating plasma glucose levels that is essential to fuel the increased energy demand associated with stress. Along with the organismal stress response, the cellular stress response, involving the synthesis of a suite of heat shock proteins (hsps), also plays an important role in protecting cellular protein homeostasis in response to stressors, including toxicants. The impact of MWWE on stress-related pathways were identified using a low-density trout cDNA microarray enriched with genes encoding for proteins involved in endocrine-, stress- and metabolism-related processes. This was further confirmed by assessing plasma hormone and metabolite levels and stress-related targeted genes and proteins expression and enzyme activities in select tissues in rainbow trout. Studies were carried out in controlled field (caging) and laboratory experiments to examine the impacts of MWWE on stress and tissue-specific metabolic responses in rainbow trout. Further in vitro studies using rainbow trout hepatocytes in primary cultures were carried out to investigate the mechanism of action of two pharmaceuticals, atenolol and venlafaxine, found in relatively high concentrations in MWWE in impacting the stress-mediated glucose response. In caged fish, MWWE exposure significantly elevated plasma cortisol and glucose concentrations, and altered the mRNA abundance of a number of stress-related genes, hormone receptors, glucose transporter 2 and genes related to immune function. When fish were exposed to an acute handling stress following a 14 d exposure to MWWE, the cortisol response was abolished and the glucose response was attenuated. The effects on cortisol did not correlate with changes in the expression of genes involved in cortisol biosynthesis, but were associated with an increase in hepatic glucocorticoid receptor (GR) protein expression. Upon further investigation in controlled laboratory studies, MWWE exposure elevated constitutive hsp 70 and hsp90 expression after 8 d exposure, which correlated with a decrease in glycogen levels in the liver in fish exposed to a high concentration of MWWE compared to control fish, pointing to a MWWE-induced increase in liver energy demand. By 14 d, glycogen stores were replenished, and this was commensurate with increases in liver gluconeogenic capacity, including increases in the activities of phosphoenolpyruvate carboxykinase (PEPCK) and alanine aminotransferase (AlaAT), along with a decrease in liver GR expression. In the heart, GR protein expression increased in treated fish, and the activity of pyruvate kinase increased, indicating an increase in glycolytic capacity. Subjecting the MWWE exposed fish to a secondary handling disturbance (acute stress) led to an attenuated plasma cortisol and glucose response compared to the control group. This corresponded with a reduced liver gluconeogenic capacity and a lower liver and heart glycolytic capacities, reflecting a disturbance in the energy substrate repartitioning that is essential to cope with stress. While it is difficult to establish causative agents from a complex mixture such as MWWE, the two pharmaceutical that were tested impacted glucose production. Specifically, atenolol and venlafaxine disrupted the epinephrine-induced glucose production, but did not modify cortisol-mediated glucose production in trout hepatocytes. The suppression of epinephrine-mediated glucose production by atenolol and venlafaxine was abolished by cAMP analogue (8-bromo cAMP) or glucagon (a metabolic hormone that increases glucose production). This suggests that both drugs disrupt β-adrenoceptor signaling, while it remains to be determined if the response is receptor isoform-specific. Altogether MWWE exposure disrupts the organismal and cellular stress responses in trout. Key targets for MWWE impact leading to the impaired cortisol and metabolic responses to stress include liver and heart GR expression, liver gluconeogenic capacity, and liver, heart and gill glycolytic capacities. Most significantly, MWWE impairs the ability to metabolically adjust to a secondary acute stressor, which is an important adaptive process that is integral to successful stress performance. From an environmental stand-point, long-term exposure to MWWE will lead to reduced fitness and will compromise the capacity of fish to cope with additional stressor, including escape from predators.

Fast paced population growth in urban areas of southern Ontario is putting increased pressure on the surrounding aquatic environment. The City of Guelph uses the Speed River to assimilate its municipal wastewater effluent. With a projected 57% population increase in the watershed by 2031, the assimilative capacity of the river may be challenged in the coming years. The Guelph Wastewater Treatment Plant uses tertiary treatment methods greatly reducing ammonia, suspended solids and phosphate concentrations in the effluent. However there are still impacts detectable related to excessive nutrients released into this relatively small river (6th order) which promotes algae and aquatic macrophyte growth. There is also concern about a variety of emerging contaminants that may enter the river and impact the health of the ecosystem. The research in this thesis examined the seasonal and spatial variability and extent of the impacts of the wastewater effluent on the riffle fish communities in the Speed River. Stable isotope signatures (δ13C and δ15N) were used to understand the changes in the dominant benthic fish species, Rainbow Darters (Etheostoma caeruleum) and Greenside Darters (E. blennioides), relative to changes in invertebrate signatures and their abundance. Rainbow Darters were extremely abundant relative to Greenside Darters at the site immediately downstream of the effluent outfall, particularly in August. The benthic invertebrate community was distinctly different downstream of the effluent outfall, especially in the summer, with a reduced abundance of Elmidae beetle larvae and increased abundance of isopods (Caecidotea intermedius) compared to upstream. δ13C and δ15N of the two darters species were similar at all sites in May and July, but in August and October Rainbow Darter signatures were more enriched in the two heavier isotopes at sites downstream of the effluent outfall. The vast majority of invertebrate taxa sampled were also enriched at the downstream sites. An analysis of Rainbow and Greenside Darter stomach contents revealed that Rainbow Darters incorporated more isopods and other invertebrates in their diet, especially at the immediate downstream sites suggesting that they are more adaptable to the altered downstream environment. The feeding habits of Greenside Darters appear to change between July and August in response to changes in habitat and food availability. They are potentially consuming food organisms with less enriched isotopic signatures, which results in their isotopic signatures not rising during these months like most of the invertebrates and other fish. Alternatively, the Greenside Darters may move across the stream to feed on invertebrates that remain unexposed to the wastewater effluent. These impacts, although subtle, may be a reflection of the Speed River ecosystem being compromised by nutrient inputs from the wastewater effluent. With the impending increase in demand on the treatment plant (e.g., population growth), ongoing treatment and infrastructure improvements may be needed in the future to maintain the current ecosystem structure.

Previous studies on fishes exposed to effluent from the Key Lake uranium mill in northern Saskatchewan have demonstrated elevated lipids in young-of-the-year pike (Esox lucius), deformities in larval pike and decreased survival of fathead minnows (Pimephales promelas). The objectives of this thesis were to evaluate possible factors that could be contributing to altered bioenergetics of juvenile northern pike inhabiting lakes receiving effluent from the Key Lake operation and to examine the effects of effluent exposure on biomarkers of oxidative stress and histopathology of target organs. Although glycogen and triglycerides stores were significantly greater in pike from exposure lakes compared to the reference, triglycerides stores of juvenile pike prey items showed no overall differences among lakes. Measures of parasitism, however, were negatively correlated with pike bioenergetics thereby reflecting a possible energetic cost of parasitism on reference lake fish. The degree of infection by intestinal parasites and gill monogeneans was greatest in reference pike and intermediate in low exposure pike, whereas high exposure pike harboured no parasites. <p>Arsenic, nickel and selenium are elevated in lakes downstream of the Key Lake mill and have been shown to be associated with increased reactive oxygen species (ROS) in biological systems causing oxidative stress. The potential for oxidative stress was assessed in pike liver and kidney using several biomarkers. Overall, the concentrations of total, reduced and oxidized glutathione and the ratio of oxidized to reduced glutathione did not differ significantly among exposure and reference pike. The activity of glutathione peroxidase was greater in high exposure than reference liver whereas, contrary to predictions, lipid peroxidation was greater in reference than exposure pike tissues. <p>Histopathological evaluations revealed greater kidney and gill pathology in reference lake pike, whereas for liver, hepatocyte morphology differed among lakes without any clear signs of pathology. Trace metal analyses of muscle showed that eight elements (arsenic, cobalt, copper, iron, molybdenum, selenium, thallium, uranium) were significantly elevated in exposure pike. These results provide only limited evidence of oxidative stress in exposure pike tissues and no evidence of histopathology despite indications that metals are bioaccumulating in tissue. Overall, the results from this thesis suggest that the health and condition of juvenile northern pike living downstream of the Key Lake uranium mill may not be compromised by effluent exposure.

Resin and fatty acids (RFA) are predominantly components of coniferous trees having the natural function of protecting against microbial damage. These compounds are released from wood during the pulping process and a fraction reaches the wastewater treatment system. RFA are acutely toxic to aquatic organisms at concentrations on the order of parts per million, and their presence has been linked to toxicity outbreaks in receiving waters following process upsets. The chronic toxicity of resin and fatty acids in complex effluent matrices is poorly understood. Furthermore, the role of hydrophobic, pulp-derived solids as a removal pathway from wastewater streams has not been comprehensively studied. The objectives of this dissertation have been to quantify the relationship between resin and fatty acid concentration and chronic toxicity and to determine the role of partitioning in the removal of these compounds from pulp mill wastewater streams. Field and laboratory studies were conducted to measure toxicity using the Microtox™ whole effluent toxicity and Ceriodaphnia dubia 7-day, survival and reproduction bioassays. One resin acid in particular, dehydroabietic acid, was found to account for a significant fraction of final effluent chronic toxicity. Dissolved and sorbed RFA concentrations were quantified by solvent extraction, methyl ester derivatization, and GC-FID analysis. Partitioning to suspended solids was found to be a major removal pathway for the RFA from the effluent treatment system. A kinetic model for flotation was applied and compared to experimental data. Flotation was found to be effective at selectively removing RFA bound to pulp-derived solids from pulp mill and bleach plant sewers at moderate to high pH.

Constructed wetlands have been widely accepted as a natural ecotechnology for wastewater treatment. Constructed wetland system is a treatment system, while it utilizes intertine relationship among water, plants, soils, microorganism and atmosphere in natural environment, and applies natural physics, chemistry and biochemical actions to remove pollutions natural. In addition, the constructed wetland can also to increase the areas to attract more wild animals as their habits. In this study, we analyzed quality of Koping River Old Railroad Bridge constructed wetlands to understand the remove efficiencies for different pollutions. The analytical results showed that A system of the constructed wetlands because some other sewage of A system flowed into the system. However, the treatment system were still better than those in B system. The average removal efficiencies of BOD5 ,COD ,NH3-N ,TP in A system equal to 81.93¢H,50.98¢H,74.89¢H,46,70¢H,respectively. However the average removal efficiencies of SS and Chlorophyll-a were increased for both A and B systems, which might because algae can grow vigorously in summer. Resulting in an increase for both Chlorophyll-a and SS. Besides, in autumn the litter effect of wetland plants might cause the concentrations of nutrients increased. In addition, in this study we also utilized emergy analysis to evaluate the economical values while comparing with a sewage treatment plant. The analytical results showed that the constructed wetlands could remove more pollutants than of the sewage treatment plant. However, the constructed wetland system could still increase the biodiversity. If they could reach steady treatment efficiencies under proper operation and maintenance. It is concluded that the constructed wetland system can provide advantages in both ecology and economics systems.

Phosphorus (P) is a pollutant in freshwater systems because it promotes eutrophication. The dairies in the North Bosque and its water body segments import more P than they export. Dairies accumulate P-rich effluent in lagoons and use the wastewater for irrigation. As more P is applied as irrigation than is removed by crops, P accumulates in the soil. During intense rainfall events, P enters the river with stormwater runoff and can become bio-available. Reducing the P applied to the land would limit P build up in the soil and reduce the potential for P pollution. Since wastewater P is associated with suspended solids (SS), the flocculants, poly-DADMAC and PAM, were used to reduce SS. To precipitate soluble P from the effluent, NH4OH was added to raise the pH. Raw effluent was collected from a dairy in Comanche County, TX, and stored in 190-L barrels in a laboratory at Texas A&M University. Flocculant additions reduced effluent P content by as much as 66%. Addition of NH4OH to the flocculated effluent raised the pH from near 8 to near 9, inducing P precipitation, further reducing the P content. The total P reduction for the best combination of treatments was 97%, a decrease from 76 to 2 mg L-1. If this level of reduction were achieved in dairy operations, P pollution from effluent application would gradually disappear.