<p> Government programs now underway in Ontario aim at removing phosphates from waste-waters at sewage treatment plants. At present, removal of phosphates is commonly accomplished by chemical precipitation with lime, alum, or iron. Lanthanum, a rare earth element, has been found to be an effective precipitant of phosphates. If lanthanum precipitate can be collected, and the lanthanum then regenerated so that it could be recycled for further phosphate precipitation, a very advantageous alternative to the above schemes would result.</p> <p> In this study, phosphates were precipitated from both distilled water and secondary effluent using lanthanum. For the two cases, a regeneration scheme for lanthanum was examined. The basic regeneration reactions were carried out to evaluate the kinetics and equilibria for different ratios of reactants and different reaction temperatures. Techniques for phase separation of reacted reagents were studied. Process design calculations were carried out to obtain order of magnitude figures for amounts and costs of chemicals required, amounts of sludge produced, and reactor sizes.</p> / Thesis / Master of Engineering (MEngr)

The environmental risk assessment of substances is introduced and the various controls used to protect the environment are outlined. The European notification system and the risk assessments required as part of the system are detailed. Through an examination of the existing European Union System for the Evaluation of Substances tool and sensitivity analyses based on variability in the measurement of physico-chemical properties for a substance, a spreadsheet model was developed to allow multiple risk assessments for the same substance to be calculated simultaneously. The development and testing of the NECXES spreadsheet tool are documented in detail. Data for the capacity and dilution factor at Sewage Treatment Plants (STPs) in England and Wales were collated and statistically analysed and compared to European default values used for generic risk assessments. The default capacity value for STPs (10,000 population equivalents) was protective of 70% of the STPs sampled. The remaining 30% however, a small number of large works, contributed 94% of the total effluent discharged from STPs in England and Wales. The STP data were used with the NEXCES tool to perform and compare probabilistic risk assessments to those calculated using deterministic methods for a number of test substances. The probabilistic calculations produced a lower median exposure concentration for water than the generic assessment for all of the test substances. Regression analysis allowed the probability of adverse effects to be quantified for the various deterministic risk values. The NEXCES tool was also used to develop a rapid assessment tool for new substances in the form of contour plots, which can be used to assess the risk of substances using minimal data. The main conclusions and contributions to the academic and industrial fields, as well as the field of environmental technology are presented. Areas where there are opportunities for further research are also outlined.

The task of this master thesis was assessment of the possibility of intensification of biological ponds, which are used for wastewater treatment, and subsequent application of selected systems to the existing wastewater treatment plant in the village Krumsin in the district Prostejov, including economic assessment. In the first part of the master thesis, I worked up the available options for the intensification of biological ponds. In the practical part of the thesis it was prepared a report of the current state of the wastewater treatment plant that serving as a basis for the design of intensification, which is also processed in the practical part. For the proposed variants of intensification was also processed economic assessment.

Recently, the presence of illicit drugs in effluents from Wastewater Treatment Plants (WWTPs) and the aquatic environment has raised concern over their possible negative effects on aquatic organisms. In this study, therefore ecotoxicological data was retrieved through a literature survey and by using the software ECOSAR. Predicted No Effect Concentrations (PNEC) of five types of illicit drugs and their metabolites including 1. Cocaine (COC) and its metabolite Benzoylecgonine (BE), 2. Amphetamine (AMPH), 3. Methamphetamine (METH), 4. Cannabis ((delta 9 tetrahydrocannabinol (THC), 11-Nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-CCOH)) and 5. 3,4-Methylenedioxymethamphetamine (MDMA) for species of three trophic levels in aquatic ecosystems derived. Predicted Environmental Concentrations (PEC) of above-mentioned drugs in twelve WWTPs’ influent and two effluents in Halland County have been measured by Swedish Toxicology Research Center (SWETOX co). Acute and chronic Risk Quotients (RQ) of the mixture of illicit drugs based upon two novel approaches calculated for the effluents of two WWTPs. Wastewater treatment plant in Ängstorp found with better removal efficiency of above- mentioned illicit drugs and the lower total RQs of (0.01&lt;MRQacute&lt;0.1; MRQchronic = 0.13) in comparison with that of Västra Stranden with the total RQs of (0.1&lt;MRQacute &lt;1; MRQchronic = 1.4). Although the RQ of WWTPs’ effluent was higher than 1 in Västra Stranden, there was no potential of risk on aquatic organisms in surface waters receiving that effluent. AMPH and Cannabis found as the most degradable substances through the WWTPs with (90-100%) of removal efficiency. Moreover, the results revealed that Cannabis (THC-COOH) was the most hazardous illicit drug on aquatic species in case of acute and chronic effects while, in terms of genotoxicology, a mixture of Cocaine metabolites found the most dangerous mixture of illicit drugs on zebrafish embryos.

Global consumption of organophosphate esters (OPs), which are used as flame retardants and plasticizers, is rapidly increasing. Their use as additives in diverse applications poses a risk as they may be emitted from the products they are added to and be further transported in the environment. Therefore, the levels, distribution, and possible sources of 15 OPs, some of which are reported to be toxic, were investigated in indoor and outdoor environments. An exposure assessment was performed, and the exposure to OPs via inhalation was examined for five occupational groups. In addition, based on the findings of the studies, the total flow of OPs in Sweden was estimated. In indoor environments, the OPs detected in air and dust varied between the sites, but generally reflected the building materials, furniture etc. used in the premises. A majority of the analysed OPs were detected in all samples, and public buildings tended to have higher levels than domestic buildings. The chlorinated OPs dominated in indoor air and wipe samples from vehicles. They were also abundant in the dust samples. Some occupational groups were significantly more exposed to OPs than others. Aircraft technicians, for example, were exposed to about 500 times more tributyl phosphate than day care centre personnel. Upon domestic and industrial cleaning, OPs are discharged with the wastewater via the sewage system to sewage treatment plants (STPs). Irrespective of the size of the STPs investigated, they had similar levels of OPs in their influents, indicating that products containing OPs are widely used by the communities they serve. In some cases, it was possible to trace elevated levels of individual OPs to specific sources. The OPs were poorly removed from the wastewater, and the chlorinated OPs especially tended to pass through the STPs without being removed or degraded. Thus, levels of OPs in their effluents were also similar, as were the levels in their sludge. Of the total amounts of OPs entering the STPs, 50% was emitted to the recipients via the effluent. Hence, there is room for significant improvement in the treatment processes. Carps living in a pond, receiving STP effluent were found to contain relatively high levels of OPs compared to perch collected in lakes from background locations. Air and road traffic were also identified as sources of OPs: the concentration of total OPs in snow samples decreased with increasing distance from a major road intersection, and OPs were detected in aircraft lubricants and hydraulic fluids and in waste oil from cars and lorries. OPs are emitted from both diffuse and direct sources to the environment and may then be spread by long-range air transport, rivers and streams. This probably explains why OPs were also detected in air and fish from background locations. Finally, OPs are ubiquitous substances in both indoor and outdoor environments. The possibility that prolonged exposure to OPs at the levels found may cause adverse effects, for instance in aqueous organisms, cannot be excluded. For example, the OP levels in snow were of the same magnitude as reported effect concentrations. Similarly, in some premises, indoor exposure to OPs was close to the suggested guideline value. However, since these studies include only a limited number of samples, and data regarding the health and environmental effects of OPs are sparse, no definitive conclusions regarding their possible environmental effects can be drawn. / Den globala konsumtionen av organiska fosfatestrar (OP) för användning som flamskyddsmedel och mjukgörare har ökat kraftigt på senare tid. Det breda användningsområdet för dessa additiv medför en risk att de kan avges från de produkter de är satta till och transporteras vidare ut i miljön. Följaktligen undersöktes källor till, halter av, och fördelning i inom- och utomhusmiljöer av 15 OP, varav en del har toxiska effekter. Vidare har exponering för OP i bl.a bostäder och offentliga byggnader beräknats. Utöver detta undersöktes exponeringen för OP via inandning hos 5 yrkesgrupper. Slutligen användes resultaten för att uppskatta det totala flödet av OP i Sverige. I de olika inomhusmiljöerna uppmättes ett flertal OP i varierande halter i damm och luft, men generellt speglade halterna byggnadsmaterial, möbler etc. som fanns i lokalerna. De offentliga lokalerna tenderade att uppvisa högre halter än privata hus, förmodligen beroende på högre brandskyddskrav. Klorerade OP dominerade i inomhusluft samt i avstrykningsprov från fordon och förekom även i höga halter i damm. Vissa yrkesgrupper var exponerade för betydligt högre halter OP än andra, t.ex. exponerades flygtekniker för upp till 500 ggr högre lufthalter av tributylfosfat jämfört med förskollärare. I samband med våtskurning i inomhusmiljöer (hushåll, industrilokaler, osv.) släpps avsevärda mängder OP ut i avloppet och når till sist reningsverk. Oberoende av storlek på reningsverken var halterna av OP relativt lika, i vardera ingående vatten och slam, vilket indikerar en bred användning av OP i samhället. I vissa fall kunde specifika källor till OP i avloppsvattnet spåras. Exempelvis hade två av reningsverken högre halter av en klorerad OP jämfört med övriga reningsverk. Dessa behandlade vatten från en skumplastfabrik, respektive en fabrik som tillverkar flamskyddad färg. Avskiljningsgraden av OP från avloppsvatten visade sig generellt vara dålig, i synnerhet klorerade OP tenderade att passera genom reningsverken utan att degraderas eller avskiljas från vattnet. Av den mängd OP som nådde reningsverken släpptes 50 % ut till miljön via utflödet. Som ett resultat av detta uppvisade karpar från en damm påverkad av utflödet från ett reningsverk höga halter OP jämfört med abborrar från referenssjöar. Det finns därför anledning att förbättra tekniken på reningsverken. Flyg- och vägtrafik kunde också identifieras som källor till OP i miljön. OP uppmättes i hydrauloljor och smörjmedel för flygplan samt i spillolja från bilar och lastbilar. Vidare minskade totalhalten OP i snöprov med ökat avstånd från en större vägkorsning. OP släpps således ut från både diffusa och direkta källor och kan sedan spridas vidare via luft och vattendrag. Därmed var det inte förvånande att OP även påträffades i luft och fisk från bakgrundslokaler. Avslutningsvis förekommer OP i varierande halter i såväl inom- som utomhusmiljöer. Det kan inte uteslutas att långvarig exponering för de halter av OP som uppmätts skulle kunna orsaka negativa effekter hos t.ex vatten- eller jordlevande organismer. I smälta snöprov från en flygplats uppmättes exempelvis halter av OP i samma storleksordning som rapporterade effektkoncentrationer. Dessutom visade sig den beräknade exponeringen av OP, i några av de provtagna inomhuslokalerna, uppgå till halter nära det föreslagna riktvärdet för OP i Tyskland. Dessa studier inkluderar dock ett begränsat antal prov och provtyper och kunskapen om dessa föreningars miljö- och hälsoeffekter är bristfällig. Därför bedöms underlaget som för litet för att några definitiva slutsatser ska kunna dras angående OPs eventuella effekter på miljön.

Depuis plusieurs années, des agents exogènes environnementaux appelés perturbateurs endocriniens (PE), sont soupçonnés d’interférer avec les fonctions essentielles de reproduction et de développement chez de nombreux organismes vivants. Pour la protection de l’Environnement et de l’Homme, la Directive Cadre sur l’Eau établit des normes de qualité environnementale (NQE) et limite la concentration de trente-trois substances et de huit autres polluants dans les eaux de surface. En revanche, elle ne prend pas encore en compte l’effet de ces substances prioritaires sur les écosystèmes et les humains notamment la perturbation endocrinienne. De plus les spécificités des perturbateurs endocriniens (courbe dose réponse, effets de mélanges etc..) rendent le processus d'identification de ces molécules complexe. Cette thèse est axée sur l’étude d’un des effets hormonaux, les plus couramment rencontrés, la perturbation estrogénique en utilisant comme outils de diagnostic le yeast estrogen screen (YES). Cette étude porte plus particulièrement sur le nord de la Tunisie où l’impact de certains PE sur le développement de poissons Aphanius fasciatus a été mis en évidence. Certains xénoestrogènes comme le cadmium et les HAP, produits générés par l’industrie locale, sont en partie mis en cause dans les malformations observées. En parallèle, certains xénoestrogènes (parabènes notamment) sont retrouvés dans les eaux de stations d’épuration. D’autres produits chimiques comme les colorants textiles et alimentaires ont également des activités endocriniennes. Dans le cadre de la surveillance de la qualité des eaux, il est nécessaire de développer des tests rapides de détection de ces perturbateurs venant complémenter les analyses chimiques. Certaines substances actives sur le système endocrinien étant peu immunogènes, l’axe de recherche développé, dans ce cadre de cette thèse, porte sur un peptide affine pour détecter une myoestrogène, l’ochratoxine A. / For several years, environmental exogenous agents called endocrine disruptors (ED) , are thought to interfere with reproduction and development fonctions in many organisms . For the Protection of the Environment and human health, the Water Framework Directive establishes environmental quality standards (EQS) and limits the ranges of thirty-three substances and eight other pollutants in surface waters. Nevertheless, it does not yet take into account the effect of these priority substances on ecosystems and humans including endocrine disruption. More than endocrine disruptors specificity (dose response curve , mixtures effect etc. .. ) make the identification process more complex. This thesis focuses on the study of hormonal effects, the most commonly encountered, estrogen disruption using the yeast estrogen screen (YES) as diagnostic tool. This study focuses particularly on the north of Tunisia, where the impact of ED on development of Aphanius fasciatus . Some xenoestrogens such as cadmium and PAH products generated by local industry are partly implicated on observed skeletal deformities. In parallel, some xenoestrogens (including parabens) are detected in the waters of sewage treatment plants. Other chemicals such as textile and food dyes also have endocrine activities. Under the supervision of water quality, it is necessary to develop rapid tests to detect endocrine disrupter and supplement chemical analyzes. Some active substances on the endocrine system is poorly immunogenic, the research axis developed in this thesis focuses on a peptide affinity for detecting a fungi toxin, ochratoxin A.

Thesis (M.Sc. (Aquaculture)) -- University of Limpopo, 2014 / Population growth in urban areas is putting pressure on sewage treatment plants. The improper treatment of sewage entering the aquatic ecosystems causes deterioration of the water quality of the receiving water body. The effect of sewage effluent on the Sand River was assessed. Eight sampling sites were selected, site 1 and 2 were upstream of the of the sewage treatment plant along the urbanised area of Polokwane, whilst sites 3, 4, 5, 6, 7 and 8 were downstream. The physicochemical parameters and coliform counts in the water samples were determined. Macroinvertebrate abundances and diversity (H') was determined at the different sites during the dry and rainy season. The water quality status of the Sand River with respect to the South African scoring system (SASS) scores and average score per taxon (ASPT) was determined. A linear regression was performed to test the correlation of the SASS scores with abundance and H'. Heavy metal concentrations in water, sediment, grass (Ishaemum fasciculatum) and fish (Oreochromis mossambicus) at the sites were evaluated. The suitability of the Sand River and surrounding borehole water for irrigation was also determined. Hierarchical average linkage cluster analysis produced two clusters, grouping two sites above the sewage treatment works and six sites downstream of the sewage effluent discharge point. Principal component analysis (PCA) identified total nitrogen, total phosphorus, conductivity and salinity as the major factors contributing to the variability of the Sand River water quality. These factors are strongly associated with the downstream sites. Canonical correspondence analysis (CCA) indicated that Chironomidae family was found on the nitrogen gradient during the dry season. However during the rainy season, Chironomidae was found in the centre of the ordination which indicated that it was ubiquitous. Escherichia coli levels (1463.73 counts/100ml) in the maturation ponds of Polokwane wastewater treatment works could potentially lead to contamination of the Polokwane aquifer. High diversity was recorded at the sites before discharge and the sites further downstream. There was significant correlation (P<0.05) between the SASS scores and macroinvertebrate diversity during the dry season (R2=0.69) and the rainy season (R2=0.77). Fish samples had significantly higher (P<0.05) iron and copper concentrations, while the vi sediment had significantly higher lead concentration (P>0.05). The United States salinity laboratory (USSL) diagram indicated that the sodium hazard (SAR) and alkalinity hazard (conductivity) was low and the Sand River and borehole water was suitable for irrigation. The residual sodium carbonate (RSC) was below 1.24 meq/l, also indicating that both the Sand River and borehole water is still suitable for irrigation. The total phosphorus concentrations fluctuated across the different site. Total nitrogen concentrations showed a gradual decrease downstream from the point of discharge. The coliform levels also showed a gradual decrease downstream. This shows that the river still has a good self-purification capacity.

Les troubles reliés à la dépression, l’épuisement professionnel et l’anxiété sont de plus en plus répandus dans notre société moderne. La consommation croissante d’antidépresseurs dans les différents pays du monde est responsable de la récente détection de résidus à l’état de traces dans les rejets urbains municipaux. Ainsi, ces substances dites « émergentes » qui possèdent une activité pharmacologique destinée à la régulation de certains neurotransmetteurs dans le cerveau suscitent maintenant de nombreuses inquiétudes de la part de la communauté scientifique. L’objectif principal de ce projet de doctorat a été de mieux comprendre le devenir de plusieurs classes d’antidépresseurs présents dans diverses matrices environnementales (i.e. eaux de surfaces, eaux usées, boues de traitement, tissus biologiques) en développant de nouvelles méthodes analytiques fiables capables de les détecter, quantifier et confirmer par chromatographie liquide à haute performance couplée à la spectrométrie de masse en tandem (LC-QqQMS, LC-QqToFMS). Une première étude complétée à la station d’épuration de la ville de Montréal a permis de confirmer la présence de six antidépresseurs et quatre métabolites N-desmethyl dans les affluents (2 - 330 ng L-1). Pour ce traitement primaire (physico-chimique), de faibles taux d’enlèvement (≤ 15%) ont été obtenus. Des concentrations d’antidépresseurs atteignant près de 100 ng L-1 ont également été détectées dans le fleuve St-Laurent à 0.5 km du point de rejet de la station d’épuration. Une seconde étude menée à la même station a permis l’extraction sélective d’antidépresseurs dans trois tissus (i.e. foie, cerveau et filet) de truites mouchetées juvéniles exposées à différentes concentrations d’effluent dilué traité et non-traité à l’ozone. Un certain potentiel de bioaccumulation dans les tissus (0.08-10 ng g-1) a été observé pour les spécimens exposés à l’effluent non-traité (20% v/v) avec distribution majoritaire dans le foie et le cerveau. Une intéressante corrélation a été établie entre les concentrations de trois antidépresseurs dans le cerveau et l’activité d’un biomarqueur d’exposition (i.e. pompe N/K ATPase impliquée dans la régulation de la sérotonine) mesurée à partir de synaptosomes de truites exposées aux effluents. Une investigation de l’efficacité de plusieurs stations d’épuration canadiennes opérant différents types de traitements a permis de constater que les traitements secondaires (biologiques) étaient plus performants que ceux primaires (physico-chimiques) pour enlever les antidépresseurs (taux moyen d’enlèvement : 30%). Les teneurs les plus élevées dans les boues traitées (biosolides) ont été obtenues avec le citalopram (1033 ng g-1), la venlafaxine (833 ng g-1) et l’amitriptyline (78 ng g-1). Des coefficients de sorption expérimentaux (Kd) calculés pour chacun des antidépresseurs ont permis d’estimer une grande sorption des composés sertraline, desméthylsertraline, paroxetine et fluoxetine sur les solides (log Kd > 4). Finalement, un excellent taux d’enlèvement moyen de 88% a été obtenu après ozonation (5 mg L-1) d’un effluent primaire. Toutefois, la caractérisation de nouveaux sous-produits N-oxyde (venlafaxine, desmethylvenlafaxine) par spectrométrie de masse à haute résolution (LC-QqToFMS) dans l’effluent traité à l’ozone a mis en lumière la possibilité de formation de multiples composés polaires de toxicité inconnue. / Mood disorders such as depression, burn-out and anxiety have increased in our modern society. Increasing amounts of antidepressant prescriptions around the world are now suspected to be the main cause of the recent detection of traces of antidepressant residues within urban wastewaters. These so-called “emerging” substances that possess pharmacological activity towards neurotransmitter regulation in the brain have raised serious concerns from the scientific community. The initial goal of the study was to better understand the fate of various classes of antidepressants present in different environmental matrices (e.g. surface waters, wastewaters, treatment sludge, and biological tissues) by developing novel reliable analytical methods that can detect, quantify and confirm antidepressants using high performance liquid chromatography coupled to tandem-mass spectrometry (LC-QqQMS,LC- QqToFMS). A preliminary study completed at the Montreal sewage treatment plant (STP) confirmed the presence of six antidepressants and four N-desmethyl metabolites in raw sewage (2 – 330 ng L-1). For this primary treatment (physico-chemical), low removal rates (≤ 15%) were obtained. Concentrations of antidepressant close to 100 ng L-1 were also detected directly in the St. Lawrence River at 0.5 km of the effluent outfall. A second study conducted at the same STP allowed the selective extraction of antidepressants in three biological tissues (e.g. liver, brain, and filet) dissected from juvenile brook trouts previously exposed to diluted untreated and treated effluents with ozone. Bioaccumulation of antidepressants was readily observed in fish tissues (0.08-10 ng g-1) for the specimens exposed to untreated effluent (20% v/v), with major distribution in liver and brain. During experiments, a significant correlation was established between the concentrations of three antidepressant detected in brain tissues and the activity of a selected biomarker of exposition (e.g. an N/K ATPase pump involved in the serotonin regulation) measured within dissected synaptosomes from trout exposed to effluents. Investigation of estimated treatment removal efficiencies from various Canadian STPs operating different disinfection modes showed that secondary treatments (biological) were more efficient than primary (physico- chemical) to remove antidepressants (mean removal rates : 30%). The highest amounts detected in treated sludge (biosolids) were obtained respectively with citalopram (1033 ng g-1), venlafaxine (833 ng g-1), and amitriptyline (78 ng g-1). Experimental calculated sorption coefficients (Kd) of each antidepressant predicted fairly good sorption capacities for sertraline, desmethylsertraline, paroxetine, and fluoxetine to solid matters (log Kd > 4). Finally, an excellent mean removal rate of 88% was obtained after ozonation (5 mg L-1) of a primary effluent. However, the characterization of new N-oxide side-products (venlafaxine, desmethylvenlafaxine) in ozonized effluent by high-resolution mass spectrometry (LC-QqToFMS) highlighted the possibility of formation of multiple polar compounds with unknown toxicity.

Large and ever-increasing numbers of chemicals, including large quantities of a broad spectrum of organic compounds are used in modern society. More than 30 000 of the more than 100 000 chemical substances registered in the EU are estimated to be daily used, of which many will be discharged into the waste-streams handled by municipal sewage treatment plants (STPs). The main objective of the work underlying this thesis was to improve understanding of the relationships between the characteristics of sewage contaminants and their sewage treatment efficiency. Further objectives were to examine the relationships between socio-economic uses of chemicals and sludge quality, and the effects of regulatory actions on sludge quality. The quality of the sewage sludge and the levels and distribution patterns of the sludge contaminants, both within and between the STPs, seem to remain quite constant over time. The overall findings indicate that the levels of contaminants in sewage sludge seem to be largely independent of the location, size and treatment techniques applied at the STPs, and generally, of the types of human activity connected to them. The total and relative concentrations of the sludge contaminants were found to be fairly constant on a dry weight basis, with some exceptions, indicating that the pollutants originate from broad usage and diffuse dispersion rather than (industrial) point sources. The proportion of cyclic methylsiloxanes recovered in sludge seems to strongly depend on their vapour pressure, which decreases with the number of siloxane units. The higher water solubility and biodegradability of organophosphorus flame retardants and plasticizers than polybrominated diphenyl ethers (PBDEs) were also reflected in lower percentages (relative to their national use) found in sludge. Significant time-trends in levels of a-third of the sludge contaminants included in the annual national measurement program were detected over a period of seven years. The levels of compounds displaying significant time-trends generally decreased following declines in the quantities used nationally. However, a quarter of these compounds showed increasing trends, of which the linear methylsiloxanes followed the same trend as used quantities. The decaBDE was also found to be increasing in sludge, probably as a result of the phase-out of pentaBDE and octaBDE. The results indicate that the STP removal efficiency of anthropogenic substances, in Sweden, is generally good and that STPs, at least those in cold climates, do not efficiently remove certain polar contaminants. A non-targeted screening (by use of environmetrics and GCxGC-TOFMS) was performed and found to fulfil the objective to assess the STP removal efficiency, with emphasis to systematically analyse which compound classes that are not efficiently removed using the current STP technology. Many polar aromatic compounds were identified to be poorly removed. The acquired data on levels, profiles and variations in sludge contaminants (sludge quality) extend both the available information and understanding of the degree and nature of sludge contamination, which should help attempts to track changes in its contaminants and revisions, if necessary, of guideline values. This thesis also contributes to improve the knowledge base for the development of future STP technologies, and that archived sewage sludge can be used in retrospective analysis of new and emerging pollutants.

Les troubles reliés à la dépression, l’épuisement professionnel et l’anxiété sont de plus en plus répandus dans notre société moderne. La consommation croissante d’antidépresseurs dans les différents pays du monde est responsable de la récente détection de résidus à l’état de traces dans les rejets urbains municipaux. Ainsi, ces substances dites « émergentes » qui possèdent une activité pharmacologique destinée à la régulation de certains neurotransmetteurs dans le cerveau suscitent maintenant de nombreuses inquiétudes de la part de la communauté scientifique. L’objectif principal de ce projet de doctorat a été de mieux comprendre le devenir de plusieurs classes d’antidépresseurs présents dans diverses matrices environnementales (i.e. eaux de surfaces, eaux usées, boues de traitement, tissus biologiques) en développant de nouvelles méthodes analytiques fiables capables de les détecter, quantifier et confirmer par chromatographie liquide à haute performance couplée à la spectrométrie de masse en tandem (LC-QqQMS, LC-QqToFMS). Une première étude complétée à la station d’épuration de la ville de Montréal a permis de confirmer la présence de six antidépresseurs et quatre métabolites N-desmethyl dans les affluents (2 - 330 ng L-1). Pour ce traitement primaire (physico-chimique), de faibles taux d’enlèvement (≤ 15%) ont été obtenus. Des concentrations d’antidépresseurs atteignant près de 100 ng L-1 ont également été détectées dans le fleuve St-Laurent à 0.5 km du point de rejet de la station d’épuration. Une seconde étude menée à la même station a permis l’extraction sélective d’antidépresseurs dans trois tissus (i.e. foie, cerveau et filet) de truites mouchetées juvéniles exposées à différentes concentrations d’effluent dilué traité et non-traité à l’ozone. Un certain potentiel de bioaccumulation dans les tissus (0.08-10 ng g-1) a été observé pour les spécimens exposés à l’effluent non-traité (20% v/v) avec distribution majoritaire dans le foie et le cerveau. Une intéressante corrélation a été établie entre les concentrations de trois antidépresseurs dans le cerveau et l’activité d’un biomarqueur d’exposition (i.e. pompe N/K ATPase impliquée dans la régulation de la sérotonine) mesurée à partir de synaptosomes de truites exposées aux effluents. Une investigation de l’efficacité de plusieurs stations d’épuration canadiennes opérant différents types de traitements a permis de constater que les traitements secondaires (biologiques) étaient plus performants que ceux primaires (physico-chimiques) pour enlever les antidépresseurs (taux moyen d’enlèvement : 30%). Les teneurs les plus élevées dans les boues traitées (biosolides) ont été obtenues avec le citalopram (1033 ng g-1), la venlafaxine (833 ng g-1) et l’amitriptyline (78 ng g-1). Des coefficients de sorption expérimentaux (Kd) calculés pour chacun des antidépresseurs ont permis d’estimer une grande sorption des composés sertraline, desméthylsertraline, paroxetine et fluoxetine sur les solides (log Kd > 4). Finalement, un excellent taux d’enlèvement moyen de 88% a été obtenu après ozonation (5 mg L-1) d’un effluent primaire. Toutefois, la caractérisation de nouveaux sous-produits N-oxyde (venlafaxine, desmethylvenlafaxine) par spectrométrie de masse à haute résolution (LC-QqToFMS) dans l’effluent traité à l’ozone a mis en lumière la possibilité de formation de multiples composés polaires de toxicité inconnue. / Mood disorders such as depression, burn-out and anxiety have increased in our modern society. Increasing amounts of antidepressant prescriptions around the world are now suspected to be the main cause of the recent detection of traces of antidepressant residues within urban wastewaters. These so-called “emerging” substances that possess pharmacological activity towards neurotransmitter regulation in the brain have raised serious concerns from the scientific community. The initial goal of the study was to better understand the fate of various classes of antidepressants present in different environmental matrices (e.g. surface waters, wastewaters, treatment sludge, and biological tissues) by developing novel reliable analytical methods that can detect, quantify and confirm antidepressants using high performance liquid chromatography coupled to tandem-mass spectrometry (LC-QqQMS,LC- QqToFMS). A preliminary study completed at the Montreal sewage treatment plant (STP) confirmed the presence of six antidepressants and four N-desmethyl metabolites in raw sewage (2 – 330 ng L-1). For this primary treatment (physico-chemical), low removal rates (≤ 15%) were obtained. Concentrations of antidepressant close to 100 ng L-1 were also detected directly in the St. Lawrence River at 0.5 km of the effluent outfall. A second study conducted at the same STP allowed the selective extraction of antidepressants in three biological tissues (e.g. liver, brain, and filet) dissected from juvenile brook trouts previously exposed to diluted untreated and treated effluents with ozone. Bioaccumulation of antidepressants was readily observed in fish tissues (0.08-10 ng g-1) for the specimens exposed to untreated effluent (20% v/v), with major distribution in liver and brain. During experiments, a significant correlation was established between the concentrations of three antidepressant detected in brain tissues and the activity of a selected biomarker of exposition (e.g. an N/K ATPase pump involved in the serotonin regulation) measured within dissected synaptosomes from trout exposed to effluents. Investigation of estimated treatment removal efficiencies from various Canadian STPs operating different disinfection modes showed that secondary treatments (biological) were more efficient than primary (physico- chemical) to remove antidepressants (mean removal rates : 30%). The highest amounts detected in treated sludge (biosolids) were obtained respectively with citalopram (1033 ng g-1), venlafaxine (833 ng g-1), and amitriptyline (78 ng g-1). Experimental calculated sorption coefficients (Kd) of each antidepressant predicted fairly good sorption capacities for sertraline, desmethylsertraline, paroxetine, and fluoxetine to solid matters (log Kd > 4). Finally, an excellent mean removal rate of 88% was obtained after ozonation (5 mg L-1) of a primary effluent. However, the characterization of new N-oxide side-products (venlafaxine, desmethylvenlafaxine) in ozonized effluent by high-resolution mass spectrometry (LC-QqToFMS) highlighted the possibility of formation of multiple polar compounds with unknown toxicity.