There are many reports indicating the presence of emerging contaminants such as: estrogen hormones, 1,4-dioxane and perfluoro-octanoic acids in the natural environment. Estrogen hormones are considered important emerging class of contaminants due to their endocrine disrupting effects. These compounds are invariably found in the environment originating mostly from natural sources. Trace concentrations of estrogen hormones (low µg/L concentrations) have been detected in municipal wastewater treatment plants and observed in receiving water bodies. 1,4-Dioxane (C4H8O2) is used as an organic solvent and solvent stabilizer numerous in chemical processes. The United States Environmental Protection Agency (US-EPA) has recognized 1,4-dioxane as a toxic chemical and a possible human carcinogen. 1,4-dioxane has been detected as a contaminant in the natural environment, drinking water supplies, superfund sites, public groundwater sources in the United States, Canada and Japan at concentrations greater than the permissible standards. Perfluorinated chemicals such as perfluoro-octanoic acid (PFOA) and perfluorooctane-sulfonate (PFOS) have been manufactured for use in a variety of industrial and consumer applications. Due to their environmental persistence, PFOAs have been detected in surface waters at a number of locations at concentrations ranging from pg/L to ng/L. Elevated concentrations of PFOAs have been measured in surface and ground waters near specific point sources. Through this project, successful attempts have been made for the destruction of emerging contaminants using ultrasound. This study deals with the optimization of various process parameters for the destruction of estrogen hormones. The influence of process parameters such as power density, reactor geometry, power intensity, ultrasound amplitude, and external mixing was investigated. Artificial neural network (ANN) approach was used to describe the interactions between optimized parameters. The important findings obtained in the present work for the optimized estrogen degradation can help tackle the challenges of scale up such as operational optimization and energy consumption. The effect of process conditions such as pH and presence of oxidizing agents on the ultrasonic destruction of 1,4-dioxane and PFOA was studied. Acidic conditions favored the destruction of both the compounds. The presence of activated sulfate radicals enhanced the reaction rate kinetics. An innovative technology using electric potential and ultrasound for the removal organic contaminants was developed. The existence of organic contaminants in ionic form under certain process conditions has led to the development of this technology. Applying a low electric potential across the probe enhances the mass transfer of the contaminants into effective reaction zone, thereby enhancing the total destruction. A two-fold increase in the reaction rates was observed. This study shows ultrasound as an efficient and effective treatment technology for the destruction of emerging contaminants. / Civil Engineering

Discharge of many organic contaminants (OCs) to the environment from industries such as pharmaceuticals, pesticides, dyestuffs, and chemical intermediates is one of the major concerns to human health and the ecosystem due to their high toxicity. Existing water and wastewater treatment techniques were not specifically designed to remove OCs, and the elimination rate can vary from negligible to over 90%. Therefore, development of treatment technologies to efficiently remove OCs from water and wastewater effluents is required. Polymeric resins are an alternative for treatment since they can selectively target certain OCs as they can be custom-synthesized during polymerization by including desired functional groups to the matrix. However, additional efforts and cost are needed for the regeneration of the exhausted resins and recycling of the sorbed contaminants. Palladium based catalysts supported on polymeric resins are a promising method to overcome regeneration problems and convert contaminants to less toxic chemicals. The main goals of this research were to (1) develop predictive models for the sorption of cationic OCs by resins based on a mechanistic understanding of the sorption mechanisms of a range of cationic OCs on two cation exchange resins and (2) synthesize novel resin-based Pd catalysts to selectively remove two toxic contaminants, i.e., 4-chlorophenol and 4-nitrophenol, convert them to less toxic chemicals, and evaluate the possibility of in situ regeneration of the spent resins. The sorption study indicated that electrostatic (ion exchange) and nonelectrostatic (adsorption) interactions between nonpolar moieties of solute and sorbent have synergistic effects on sorption. It also established predictive models for estimating the sorbed concentrations of a target contaminant on a given resin at any environmentally relevant pH. Our findings point to the significant role of adsorption in the overall catalytic reactivity. The rate determining step (RDS) switched from adsorption to surface reaction with increasing concentration of the reactant. This observation was confirmed by good fitting of the reaction kinetics to the Langmuir-Hinshelwood model developed based on the respective RDS. Our results demonstrated that Pd-resin composites are advantageous to water treatment because they can avoid the conventional resin regeneration process and enable recycling of reaction products of smaller environmental impacts. / Civil Engineering

There are many reports indicating the presence of various emerging contaminants (ECs) in treated wastewater and other water sources. The detection of such contaminants in the environment and the ability of these contaminants to pose potential threats to the environment at very low concentrations have led to a need for more efficient treatment technologies. Cyclodextrins (CDs) have gained significant interest as an alternative adsorbent for water and wastewater treatment because of their unique physico-chemical characteristics and excellent selectivity towards organic compounds. The property of CD to form inclusion complexes with various molecules through host-guest interactions has made it a useful compound for the removal of a number of contaminants from water and wastewater. The overall goal of the study is to identify and develop a novel adsorbent for the removal of ECs of interest. The specific objectives are a) to synthesize various beta-cyclodextrin (BCD) based adsorbents by coating BCD onto different supports such as silica, filter paper, iron oxide, and zeolite, b) to perform batch and column experiments using the developed adsorbents, c) to evaluate the performance of the adsorbents in different water matrices such as MQ water, simulated wastewater in presence of humic acid, and real municipal wastewater, d) to study the regeneration potential of the adsorbents. In this research, various (BCD) based hybrid adsorbents were synthesized and their performances were evaluated based on the removal of selected ECs. At first, chemically bonded BCD onto silica particles as hybrid adsorbents were synthesized by using crosslinking agents and copolymers. Three different methods were used to synthesize 14 different BCD coated silica adsorbents. The adsorbent prepared by reacting BCD with hexamethylene diisocyanate (HMDI) as crosslinking agent and dimethyl sulfoxide (DMSO) as solvent showed best results in removing the ECs studied. The adsorbent showed more than 95% removal of 17β-estradiol (in single component) and more than 90% of most of the estrogens (mixture of 12), more than 99% of perfluorooctanoic acid (PFOA) (in single component) and more than 90% of most of the PFCs (mixture of 10), and a maximum of 90% removal in case of BPA. The adsorption capacity of the developed adsorbent was observed to be higher for the removal of 17β-estradiol and PFOA than that of commercially available activated carbon (F400) in MQ water. In order to represent the real environmental scenario, further batch experiments were conducted for the removal of two PFCs (PFOA and PFOS (perfluorooctane sulfonic acid)), 17β-estradiol, and BPA at environmentally relevant concentrations from wastewater. The adsorbent was effective in removing the ECs that were spiked in the secondary effluent of a municipal wastewater treatment plant. Furthermore, the adsorbent was successfully regenerated with methanol over four cycles without significant loss in its adsorption capacity for the removal of PFOA and estrogens. Ozonation as an alternative method of regeneration was also used and the process was also very effective in regenerating the adsorbent over seven successive cycles for the removal of BPA and 17β-estradiol. The characterization of the adsorbents using FTIR, TGA, and TEM confirmed the coating of BCD onto silica particles. The TGA results showed high thermal stability of the adsorbent (upto 300oC). As an alternative to chemical impregnation, another method of synthesis was developed where various BCD based hybrid adsorbents were synthesized by physically impregnating hydroxypropyl BCD (hpBCD) polymer onto three different supports: iron oxides, zeolite, and filter paper. The hpBCD impregnated filter papers were synthesized by solvent evaporation method and different adsorbents were synthesized by varying the polymer loadings. The polymer loading was optimized based on the performance of the modified (polymer impregnated) filter paper in terms of its filtration capacity as well as adsorption capacity to remove PFOA and BPA. The magnetic adsorbent was prepared by mixing hpBCD polymer with iron oxide (Fe3O4) particles. It was observed that by increasing the mixing time of the support (Fe3O4) with the polymer from 48 to 96 hr, the adsorption capacity of the adsorbent (hpBCD polymer coated Fe3O4) could be significantly enhanced. The same approach was also used to synthesize hpBCD polymer coated zeolite adsorbent and both adsorbents (hpBCD/zeolite and hpBCD/Fe3O4) were effective in removing the selected ECs from MQ water, simulated water, and wastewater. / Civil Engineering

The Falconbridge study was a historical prospective mortality study conducted at a nickel company in Sudbury Ontario. The study included all the men that worked there for at least 6 months between 1950 and 1976 with an update in 1984. Nearly 11500 subjects were included in the cohort. From here all the subjects identified with lung cancer were selected and matched with different number of healthy subjects (1:1, 1:2, 1:4, 1:6, 1:8, 1:10). Information was generated of the time-intensity of different contaminants normally found in the mining atmosphere and eight of such contaminants were evaluated for the different sets of case:control. Given the fact that some contaminants present a time delay effect, an assessment of this factor was also made using the subject initial and final time of exposure to each contaminant. Finally a variable selection was performed for the three data sets generated in the project. The results showed that some of the postulated contaminants did have an effect in the final outcome, however, because of the complex effect between the different chemical compounds a definite conclusion is not given. / Thesis / Master of Science (MSc)

De nombreuses familles de polluants organiques en provenance de différentes sources se retrouvent dans les milieux aquatiques continentaux et littoraux. Ces molécules, dont les lipophiles et les persistantes, sont souvent présentes à l'état de trace dans la fraction dissoute. L'utilisation de compartiments concentrateurs comme les sédiments rend alors plus accessible l'évaluation des concentrations ambiantes du milieu. L'objectif de la thèse a été d'évaluer l'exposition en zones côtières aux différentes familles de contaminants organiques « émergents » incluant les filtres UV, les alkylphénols et les alkylphénols polyéthoxylés, ainsi que « persistants-classiques » incluant les hydrocarbures aromatiques polycycliques et les polychlorobiphényles dans les sédiments et, éventuellement, dans les eaux. Un important effort de recherche a été accordé à l'étude des variations spatiales et temporelles des contaminants sélectionnés dans les sédiments, permettant ainsi l'acquisition d'un premier jeu de données nationales (libanais) représentatif pour ces familles de contaminants.Trois rivières en Méditerranée orientale et leur environnement côtier ont été pris comme cas d'étude en plus de la côte d'une petite ville et ses sites portuaires qui ont été sélectionnés afin de compléter l'étude en milieu côtier. Un premier aperçu des niveaux de ces contaminants hydrophobes dans les zones côtières recevant des apports typiques de la Méditerranée orientale est ainsi fourni. Les résultats des analyses chimiques ont clairement montré l'impact des rejets des effluents non traités dans les zones côtières via les entrées des rivières et les déversements directs le long de la côte, en absence des activités récréatives (pour les filtres UV) et de rejets industriels (pour les alkylphénols et les alkylphénols polyéthoxylés). Les zones de transition peuvent être à l'origine de la contamination de l'environnement côtier des trois rivières par ces polluants émergents en absence des apports marins. Des concentrations élevées en hydrocarbures aromatiques polycycliques et en polychlorobiphényles ont été mesurées dans les sédiments prélevés en milieu côtier. Cette contamination a persisté des années après la marée noire qui a envahi la côte Est-Méditerranéenne en 2006. Nos résultats globaux indiquent que les concentrations mesurées dans les sédiments des trois rivières étudiées et du littoral peuvent être classées parmi les niveaux les plus élevés détectés dans le pourtour du bassin méditerranéen et pouvant induire des effets toxiques chez le biota aquatique.Ce travail peut être d'une importance primordiale pour la région Est-Méditerranéenne, et plus particulièrement pour le Liban, un pays qui, malgré d'être parmi les signataires de la convention de Barcelone pour la protection de la mer Méditerranée et qui est, par la suite, impliqué dans la surveillance de la qualité de son milieu marin, souffre jusqu'à présent des rejets de différents types d'effluents non traités le long de ces côtes en absence des stations d'épuration. / Many organic pollutants issued from different sources are present into freshwater and coastal waters. Since these lipophilic contaminants are present at trace levels in water, accumulator compartments such as sediments can be used to assess their concentration in aquatic systems. The objective of the thesis was to assess the exposure in coastal areas to the various families of organic contaminants namely "emerging pollutants" including UV filters, alkylphenols, alkylphenol polyethoxylates, and "persistent pollutants" including polycyclic aromatic hydrocarbons and polychlorinated biphenyls in sediments and water. A major research effort has been given to the investigation spatial and temporal dynamics of the selected pollutants in sediment, allowing the acquisition of a first set of national data (Lebanese).Three rivers and their coastal environment in the eastern Mediterranean have been taken as a case study in addition to the small coastal city that was selected to complete the study in the coastal environment. A first overview of the levels of these hydrophobic contaminants in coastal areas receiving typical eastern Mediterranean inputs is thus provided. The results of chemical analyzes have clearly shown the impact of discharges of untreated effluents into coastal areas via inputs from rivers and direct discharges along the coast, without recreational activities (for UV filters) and industrial effluents discharges (for alkylphenols and alkylphenol polyethoxylates). Transition zones may act like a source of contamination of the three rivers coastal environment in the absence of marine inputs. Elevated concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls were measured in sediments in coastal environments. This contamination has persisted for years after the oil spill that has invaded the Mediterranean coast in 2006. Our overall results indicate that concentrations in sediments of the three studied rivers and the coastline can be classified among the highest levels detected in the Mediterranean basin and may induce toxic effects in aquatic biota.This work may be of paramount importance for the East-Mediterranean region, and particularly for Lebanon, a country which, despite being a signatory to the Barcelona Convention for the Protection of the Mediterranean Sea and is, subsequently involved in monitoring the quality of its marine environment, suffers far different types of discharges of untreated effluent along its coast in the absence of wastewater treatment plants.

Objetivo. Comparar a qualidade do ar externo com o ambiente interno das estações Clínicas e Praça da Sé do Metrô de São Paulo, quantificando e qualificando os contaminantes microbiológicos e atmosféricos. Propõe-se com este estudo promover o conhecimento de fatores sobre a qualidade do ar e das condições de higiene e saúde destes locais, contribuindo para a melhoria da qualidade de vida dos trabalhadores e usuários do sistema. Métodos. As amostras foram realizadas no período de Julho a Novembro de 2005. Os fungos foram coletados com o impactador de Andersen de um estágio com volume de aspiração de 28 l/min por um tempo de 10 minutos por amostra, e como meio de cultivo Agar Sabouraud Dextrose a 4 por cento . A quantificação e identificação foram feitas por meio de análises de lâminas do material microbiológico em microscópio óptico, coradas com azul de lactofenol. Para o dióxido de nitrogênio utilizou-se difusor passivo com trietanolamina como substância adsorvente e as análises foram realizadas por espectrofotometria. O difusor passivo para avaliação da concentração de benzeno é do tipo membrana, com carvão ativado como substância adsorvente e a análise por cromatografia gasosa. O tempo de exposição para estes amostradores foi de 30 dias. O PM10 foi medido com um monitor contínuo, com leitura direta. Foram instalados dois equipamentos em cada estação por um período de 7 dias. Resultados. Os estudos indicam a presença de fungos comuns com predominância para o Cladosporium sp (52 por cento ), Alternaria sp (17 por cento ) e Penicillium sp (13 por cento ) e em proporções semelhantes interna e externamente às estações. A concentração média de NO2 no interior das estações, foi de 73,9JPñ (VWHV YDORUHV Vão semelhantes às medições externas realizadas com o equipamento de Espectroscópia de Absorção por Diferencial Óptico (DOAS) e os valores medidos pela estação de monitoramento da CETESB, instalado na FSP/USP. Os valores viii máximos encontrados para o benzeno foram de 5,7JPñ QR LQWHULRU GDV estações e 6,2JPñQRDPELHQWHH[WHUQR230LQGLFRXYDORUHVHOHYDGRV sendo o valor médio, para a estação Clínicas de 312,4JPñ PHGLGRV QD SODWDIRUPDHJ/m³ no mezanino, na estação Praça da Sé verificamos a concentração de 150,9JPñ QD SODWDIRUPD GD OLQKD H JPñ QD plataforma da linha 3. Conclusões. O presente estudo possibilitou a avaliação e comparação dos níveis de poluição ambiental interno e externo às estações. A constatação da predominância de fungos comuns no ar não indica a ausência de riscos para a saúde humana, pois o seu impacto depende da suscetibilidade dos indivíduos expostos. A concentração de NO2 e benzeno encontradas no ambiente interno e externo são de mesma ordem de grandeza, o que indica que estes contaminantes têm a mesma fonte de origem. A alta concentração de PM10 representa uma maior preocupação. Para este contaminante deve-se avaliar a composição do material encontrado e seu grau de toxicidade / Objective. Compare the air quality outdoors with the indoors environment at Clínicas and Praça da Sé Stations of the São Paulo Subway, measuring the quantity and quality of the existing microbiological and atmospheric contaminants. The purpose of this study is to promote the knowledge of factors related to the air quality and the health and hygiene conditions in these places, contributing to the improvement of the quality of life of employees and users of the system. Methods. The samples were taken from July to November 2005. The fungi were taken by one-stage Andersen impactor with aspiration volume of 28 l/min for a period of 10 minutes per sample, making use of Agar Sabouraud Dextrose at 4 per cent for the culture. The quantification and identification are done by the analysis of slides with the microbiological material in an optical microscope, colored with lactofenol blue. For the nitrogen dioxide, a passive diffuser was used with triethanolamine as absorbing substance and the analysis was done by spectrophotometry, the passive diffuser used to evaluate the concentration of benzene is the membrane type with activated carbon as absorbing substance making use of gas chromatography analysis. The exposure period for these samplers was 30 days. The PM10 was measured with a continuous monitor, with direct reading. This equipment uses fibreoptic sensors for the identification of the size and concentration of the particles which are sucked by a diaphragm pump, passing through a measuring chamber which also measures the temperature and the air humidity. Two pieces of this equipment were installed in each station for a period of seven days. Results. The studies indicate the presence of ordinary fungi with the prevalence of Cladosporium sp (52 per cent ), Alternaria sp (17 per cent ) and Penicillium sp (13 per cent ) in similar proportions both indoors and outdoors. The indoor average concentration of NO2 was 69,5g/m³. These values are similar to the outdoor x results obtained with the equipment for Differential Optical Absorption Spectroscopy (DOAS) and the values measured by CETESB control station, located at FSP/USP. The values found for benzene ranged from 3,8 to 6,2g/m³, indicating an average of 5,0g/m³. The PM10 indicated high values with an average, at Clínicas Station, of 312,4 g/m³ measured in the platform and 243,9 g/m³ in the mezzanine. At Praça da Sé Station the concentration on the platforms was 150,9 g/m³ for line 1 and 124,2 g/m³ for line 3. Conclusions. The present study permitted the assessment and comparison of the environmental pollution levels inside and outside the stations. The verification of the predominance of common fungi in the air doesn\'t indicate the absence of risks for the human health, because it impact depends on the exposed individuals\' susceptibility. The concentration of NO2 and benzene found in the internal and external atmosphere are of same order of greatness, what indicates that these pollutants have the same origin source. The high concentration of PM10 represents a larger concern. This pollutant it should be evaluated the composition of the found material and his toxicity degree

Le développement des activités industrielles et agricoles du siècle dernier a eu pour conséquence le rejet de substances chimiques dans l’environnement, qui contaminent les écosystèmes, et peuvent s’accumuler dans les plantes, les sédiments, et le long des chaînes alimentaires. Il apparait primordial d’effectuer une évaluation du risque écologique associé à la présence de ces composés dans les milieux naturels et les espèces sentinelles sont des outils judicieux pour déterminer l’exposition des individus et évaluer les conséquences sur les organismes. Les amphibiens et les reptiles possèdent des caractéristiques écologiques et biologiques qui les rendent potentiellement intéressants en tant qu’espèces sentinelles. L’objectif des études présentées dans cette thèse est de déterminer la disponibilité de certaines substances dans l’environnement, et d’évaluer les effets de la contamination environnementale sur les organismes en utilisant plusieurs espèces de reptiles et d’amphibiens, (i) en mesurant les niveaux de polluants accumulés dans les tissus d’espèces de reptiles ; (ii) en évaluant l’influence d’un habitat contaminé sur la morphologie d’adultes de crapaud commun (Bufo bufo) ; (iii) en mesurant de manière expérimentale l’impact d’une molécule fréquemment retrouvée dans l’environnement sur le développement de têtards de crapaud commun. Nos résultats montrent d’une part que les reptiles accumulent efficacement les polluants organiques et les éléments traces métalliques dans leurs tissus, et permettent d’évaluer efficacement la contamination globale d’une zone, mais aussi de mettre en évidence des pollutions ponctuelles localisées. D’autre part, nos travaux montrent une influence de l’habitat agricole sur la morphologie du crapaud commun, potentiellement causé par la présence de contaminants dans ces milieux. Enfin, nous avons pu mettre en évidence un effet de concentrations faibles d’AMPA, métabolite principal du glyphosate, sur le développement de têtards de crapaud commun. Les amphibiens constituent donc des organismes efficaces pour étudier l’impact de la contamination de l’environnement sur les caractéristiques individuelles. Nos travaux montrent ainsi l’utilité de certaines espèces de reptiles et d’amphibiens comme espèces sentinelles de la présence de contaminants dans l’environnement et de leur impact potentiel sur les organismes. Les travaux en écotoxicologie qui portent sur ces organismes restent trop rares, et il est impératif de développer la recherche dans ce domaine, pour participer de manière efficace à l’évaluation du risque environnemental. / The development of industrial and agricultural activities over the last century has resulted in the release of chemicals into the environment, which contaminate ecosystems and can accumulate in plants, sediments and across food webs. As such, it is essential to conduct an assessment of the ecological risk associated with the presence of these compounds in natural environments. Achieving this can be aided through the study of sentinel species, which can be used to determine exposure rates of individuals and assess how these subsequently impact wildlife. Amphibians and reptiles display ecological and biological characteristics that may make them particularly attractive as sentinel species. The collection of studies presented in this thesis aims to determine the availability of contaminants in the environment and estimate the effects of this on individual traits of living organisms. Across several species of reptiles and amphibians we, (i) measured levels of pollutants accumulated in the tissues of several reptile species ; (ii) assessed how contaminated habitats impact the morphology of adult common toads (Bufo bufo) ; and (iii) experimentally measured the influence of a molecule frequently detected in the environment on common toad tadpoles’ growth. Results show that reptiles efficiently accumulate organic pollutants and metal trace elements in their tissues, and thereby allow efficient evaluation of the global contamination of an area, as well as the occurrence of localized pollution events. In addition, our work shows an influence of the agricultural habitat on the morphology of adult common toads, which is potentially a consequence of the presence of chemicals in these environments. Finally, we were able to demonstrate an effect of low concentrations of AMPA, the main metabolite of glyphosate, on the development of common toad tadpoles. Amphibians are therefore efficient organisms to study the impact of environmental contamination on individual characteristics. Our work shows the usefulness of certain species of reptiles and amphibians as sentinel species for the presence of contaminants in the environment, and their potential impact on organisms. Ecotoxicological studies on these organisms remain too scarce, and it is imperative to develop research in this field, to participate effectively in the assessment of environmental risk.

First Nations peoples experience many benefits from eating locally-harvested wild foods, but these benefits must be considered along with the potential risks associated with exposure to environmental contaminants. Unlike store-bought foods, wild foods are an important traditional resource and a significant source of dietary protein, essential minerals and polyunsaturated fatty acids, believed to help in the prevention and treatment of obesity and obesity-related diseases such as type-2 diabetes mellitus. Wild foods continue to be an important and healthy food choice for First Nations peoples; however, they are also a primary source of dietary mercury, polychlorinated biphenyls (PCBs) and other persistent organic pollutants (POPs). To assess the effects of wild food consumption on dietary markers and contaminant accumulation, we grouped individuals from two remote Oji-Cree First Nations communities of north-western Ontario (n=71) according to their level of wild food consumption. In this study, I observed significantly higher organic contaminants in blood and higher mercury concentrations in hair for individuals consuming greater amounts of wild food. Age-adjusted contaminant concentrations were on average 3.5-times higher among high-frequency wild food consumers, with many exceeding federal and international health guidelines for mercury and PCB exposures. Contaminants in these populations approach, and in some cases exceed, threshold levels for adverse effects with potential consequences especially for prenatal development. Here, I also investigated the potential for stable isotope ratios of carbon and nitrogen (δ13C and δ15N) to serve as dietary markers and found strong positive correlations between stable isotopes and frequency of wild food and fish consumption. Frequency of fish consumption and δ15N was also shown to be positively correlated with mercury concentrations in hair and PCB concentrations in plasma. The results of this thesis demonstrate that known differences in dietary behaviour are clearly reflected in stable isotope ratios and contaminant concentrations. The data also show that contaminant exposures to those consuming wild foods in remote Boreal ecosystems is comparable to those associated with serious health effects in industrialized areas, and the problem of contaminants in wild foods is more widespread than the available literature would have led us to believe. These results affect our appreciation of contaminant exposures to First Nations peoples and will have implications for dietary choices, particularly if individuals are encouraged to consume greater amounts of wild foods for their proposed health benefits. We recommend further attention be given to the risks of contaminants in locally-harvested wild foods when promoting the benefits of their consumption to First Nations people as the problem of contaminants in remote communities practicing traditional lifestyles is often underreported and underplayed.

First Nations peoples experience many benefits from eating locally-harvested wild foods, but these benefits must be considered along with the potential risks associated with exposure to environmental contaminants. Unlike store-bought foods, wild foods are an important traditional resource and a significant source of dietary protein, essential minerals and polyunsaturated fatty acids, believed to help in the prevention and treatment of obesity and obesity-related diseases such as type-2 diabetes mellitus. Wild foods continue to be an important and healthy food choice for First Nations peoples; however, they are also a primary source of dietary mercury, polychlorinated biphenyls (PCBs) and other persistent organic pollutants (POPs). To assess the effects of wild food consumption on dietary markers and contaminant accumulation, we grouped individuals from two remote Oji-Cree First Nations communities of north-western Ontario (n=71) according to their level of wild food consumption. In this study, I observed significantly higher organic contaminants in blood and higher mercury concentrations in hair for individuals consuming greater amounts of wild food. Age-adjusted contaminant concentrations were on average 3.5-times higher among high-frequency wild food consumers, with many exceeding federal and international health guidelines for mercury and PCB exposures. Contaminants in these populations approach, and in some cases exceed, threshold levels for adverse effects with potential consequences especially for prenatal development. Here, I also investigated the potential for stable isotope ratios of carbon and nitrogen (δ13C and δ15N) to serve as dietary markers and found strong positive correlations between stable isotopes and frequency of wild food and fish consumption. Frequency of fish consumption and δ15N was also shown to be positively correlated with mercury concentrations in hair and PCB concentrations in plasma. The results of this thesis demonstrate that known differences in dietary behaviour are clearly reflected in stable isotope ratios and contaminant concentrations. The data also show that contaminant exposures to those consuming wild foods in remote Boreal ecosystems is comparable to those associated with serious health effects in industrialized areas, and the problem of contaminants in wild foods is more widespread than the available literature would have led us to believe. These results affect our appreciation of contaminant exposures to First Nations peoples and will have implications for dietary choices, particularly if individuals are encouraged to consume greater amounts of wild foods for their proposed health benefits. We recommend further attention be given to the risks of contaminants in locally-harvested wild foods when promoting the benefits of their consumption to First Nations people as the problem of contaminants in remote communities practicing traditional lifestyles is often underreported and underplayed.

Le cadre réglementaire défini par la Directive Cadre sur l’Eau impose le développement de méthodologies fiables d’évaluation et/ou de caractérisation de l’état de santé des écosystèmes aquatiques. L’objectif de ce travail de thèse était d’identifier les rôles relatifs des paramètres des milieux aquatiques (température, cycle saisonnier, minéralisation), des caractéristiques des populations et des pressions anthropiques sur les réponses des biomarqueurs chez un organisme aquatique modèle, la moule zébrée (Dreissena polymorpha). Une espèce sœur, Dreissena rostriformis bugensis, arrivée plus récemment dans nos cours d’eau, a été suivie en parallèle et son potentiel en tant que biomoniteur a également été évalué. Pour cela, une batterie d’une douzaine de biomarqueurs sub-cellulaires a été mesurée dans différentes populations des deux espèces vivant dans des milieux contrastés, à différentes périodes de l’année, mais aussi lors de stress standardisés en laboratoire. Les biomarqueurs choisis correspondaient à différentes fonctions physiologiques et/ou antitoxiques, et des réponses à fortes pertinence écologiques, telles que la consommation d’oxygène ou l’activité de filtration, ont ponctuellement été suivies. Ces différents paramètres ont permis d’interroger les notions de sensibilité et de vulnérabilité des populations et de mieux comprendre les facteurs déterminant les réponses des biomarqueurs. Les différences inter-populationnelles montrent que l’accumulation des contaminants par les organismes et leurs réponses biologiques sont bien dépendantes de la qualité du biotope propre à chaque population, mais aussi de la saison, un facteur confondant qui doit donc être pris en compte lors de campagnes de biosurveillance. De fortes différences de réponse des biomarqueurs entre les deux espèces ont aussi été observées, aussi bien in situ que lors des expositions en laboratoire, soulignant la nécessité de bien différencier ces deux espèces, pourtant très proches. La nouvelle arrivée, D. r. bugensis, présente des réponses plus plastiques in situ, mais semble moins capable de gérer des stress aigus lors d’expositions en laboratoire. A l’inverse, D. polymorpha, arrivée il a 200 ans en France, semble mieux adaptée, avec une variabilité de réponse moins marquée et une meilleure tolérance aux contaminants. Ces travaux de thèse s’inscrivent dans le cadre de la convention BIOMICS, réalisée en collaboration avec l’ONEMA. Ils montrent que ces deux espèces sont aptes à nous renseigner sur l’état de contamination du milieu dans lequel elles vivent, même si les grilles d’interprétation peuvent être différentes de l’une à l’autre. Les variations des réponses des biomarqueurs au niveau sub-cellulaire témoignent de façon précoce de modifications de la qualité du milieu. Certains biomarqueurs semblent toutefois plus informatifs que d’autres, la batterie mesurée pourrait donc être réduite. A l’avenir, ces travaux permettront une meilleure lecture et interprétation des biomarqueurs mesurés dans des populations autochtones ou transplantées, et attestent de l’intérêt des biomarqueurs en tant qu’outils d’évaluation de la qualité des milieux aquatiques / The regulatory framework defined by the Water Framework Directive requires the development of reliable methodologies for assessing and / or characterizing the health status of aquatic ecosystems. The objective of this thesis was to identify the relative roles of environmental parameters (temperature, seasonal cycle, mineralization), population characteristics and anthropic pressures on biomarker responses in a model aquatic organism, the zebra mussel (Dreissena polymorpha). A sister species, Dreissena rostriformis bugensis, which invaded more recently our waterways, has been used in parallel and its potential as a biomonitor has also been evaluated. For this purpose, a battery of a dozen sub-cellular biomarkers was measured in different populations of the two species living in contrasting environments, at different times of the year, but also under laboratory stresses. The selected biomarkers corresponded to different physiological and / or antitoxic functions, and responses with high ecological relevance, such as oxygen consumption or filtration activity, were occasionally followed. These various parameters allowed to question the concepts of sensitivity and vulnerability of the populations and to understand the factors determining biomarker responses. Inter-population differences showed that the accumulation of contaminants by organisms and their biomarker responses depend on environmental quality at the originating site of each population, but also on the season, a confounding factor which must therefore be taken into account during biomonitoring programs. Strong differences in biomarker responses between the two species were also observed, both in situ and during laboratory experiments, emphasizing the need to differentiate the two species, so close they are. The recent invader, D. r. bugensis, presents more plastic responses in situ, but appears less able to manage acute stress in laboratory. Conversely, D. polymorpha, which is about 200 years old in France, appears to be better adapted, with less response variability and a better tolerance to contaminants. This thesis work is part of the BIOMICS convention, carried out in collaboration with ONEMA. It shows that these two species are able to inform about the contamination status of their environment. Variations in biomarker responses at the sub-cellular level indicate early changes in environmental quality. Some biomarkers, however, seem more informative than others do, so the measured battery could be reduced. In the future, this work will allow a better reading and interpretation of biomarkers measured in autochthonous or transplanted populations, and attest the value of biomarkers as tools for assessing aquatic environment quality