The genotoxicity of energetic compounds (i.e., explosives) that are known to be present in contaminated soils at military training sites has not been extensively investigated. Thus, the Salmonella mutagenicity and Muta(TM)Mouse assays were employed as in vitro assays to examine the mutagenic activity of twelve explosive compounds, as well as three soil samples from Canadian Forces Base Petawawa. Salmonella analyses employed strains TA98 (frameshift mutations) and TA100 (base-pair substitution mutations), as well as the metabolically-enhanced YG1041 (TA98 background) and YG1042 (TA100 background), with and without exogenous metabolic activation (S9). For Salmonella analyses, the results indicate that ten of the explosive compounds were mutagenic, and consistently elicited direct-acting, base-pair substitution activity. All three soil samples were also observed to be mutagenic, eliciting direct-acting, frameshift activity. Mutagenic potencies were significantly higher on the metabolically-enhanced strains for all compounds and soil samples. For Muta(TM)Mouse analyses on FE1 cells, the results indicate that the majority of explosive compounds did not exhibit mutagenic activity. All three soil samples elicited significant positive responses (PET 1 and PET 3 without S9, and PET 2 with S9), and although there is some evidence of a concentration-related trend, the responses were weak. Correspondence of the mutagenic activity observed with the two assay systems, for both the explosive compounds and soil samples, was negligible. The differential response is likely due to differences in metabolic capacity between the two assay systems. Furthermore, it is likely that there are unidentified compounds present in these soil samples that are, at least in part, responsible for the observed mutagenic activity. Additional testing of other explosive compounds, as well as soil samples from other military training sites, using a variety of in vitro and in vivo assays, is warranted in order to reliably estimate mutagenic hazard and subsequently assess risk to human health.

Unlike municipal water supplies, provincial regulations do not require systematic testing of domestic well water, which may adversely impact local residents should contamination occur. Private wells are typically shallow relative to municipal wells, and thus, are particularly vulnerable to sources of surficial contamination if preferential recharge pathways such as natural fractures or faulty seals are present. In order to determine the relative importance of well seal integrity as a preferential pathway, a practical detection method was developed based on infiltrometry. This method successfully detected faulty well seals in a wide range of geological settings across Canada, including: Hobbema, Alberta; Lindsay, Ontario; and Chelsea, Québec. It was most successful in areas of minimal heterogeneity and where the surficial geology is composed of fine-grained sediments. The community of Chelsea (Québec) was also the primary study site to examine a range of factors affecting water quality including physical characteristics, faulty well seals, other anthropogenic activities and seasonality. Water samples were collected over a period of 14 months and analyzed for bacteria and major-ion chemistry. The results show that the consideration of physical features alone is not enough to predict vulnerability in the study area. Seasonal fluctuations in ionic concentrations (e.g. ionic strength, NO3-N and Cl-) and coliform bacteria are observed and result from disperse and rapid recharge events. Multivariate analysis techniques (e.g. principal components analysis and hierarchical cluster analysis) demonstrate that preferential recharge pathways and anthropogenic activities, such as domestic effluents affect the groundwater quality. The data and findings of this study were used to assist in the design of a probabilistic risk assessment model based on the Poisson distribution. This study demonstrates the complexity and the challenges related to bacterial contamination in drilled wells. In spite of these challenges, this analysis was useful as a baseline to assess the impact of anthropogenic activities, and may be used in future studies to assist municipalities in the evaluation and protection of groundwater supplies.

Oysters are filter-feeding bivalves, which filter water for nutrients and often accumulate contaminants and human pathogens such as Vibrio parahaemolyticus and Vibrio vulnificus naturally occurring in the marine environment. These naturally occurring pathogens have been frequently isolated from raw shellfish, particularly oyster, in the United States and are recognized as the leading causes of human gastroenteritis associated with seafood consumption. Human illness caused by consumption of raw oyster contaminated with V. parahaemolyticus and Vibrio vulnificus typically results in reduced sales of oysters and a consequent significant financial burden for the producers. The United States produces more than 27 million pounds of oysters each year with a large portion of them being produced from the coastal water of the Gulf of Mexico. It is estimated that 20 million Americans eat raw shellfish and consumption of raw oyster is responsible for about 95% of all deaths associated with seafood consumption in the U.S., making raw oysters one of the most hazardous seafoods. Several post-harvest processes, including low temperature pasteurization, freezing, high pressure processing and irradiation, have been reported capable of reducing Vibrio contamination in raw oysters. However, most of them require either a significant amount of initial investment or operation costs, and oysters are often killed during processing. Cost-effective post-harvest processing for reducing V. parahaemolyticus in raw oysters without significant adverse effects on the oysters remains to be developed. This study was conducted to determine impacts of low-temperature (15, 10 and 5°C) depuration and frozen storage on reducing V. parahaemolyticus and V. vulnificus in raw oysters. Depuration of the Gulf oyster (Crassostrea virginica) with electrolyzed oxidizing (EO) water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1,131mV) containing 3% NaCl was found ineffective on reducing both V. parahaemolyticus and V. vulnificus in the oysters. Reductions of V. parahaemolyticus and V. vulnificus in oyster after 48 h of EO water depuration at 22°C were limited to 0.7 and 1.4 log MPN/g, respectively. Depuration with EO water at lower temperatures did not enhance reductions of Vibrio in the oysters. Greater reductions of V. parahaemolyticus (1.2 log MPN/g) and V. vulnificus (2.0 log MPN/g) were observed when the oysters were depurated with artificial seawater (ASW) at room temperature (22°C) for 48 h. Decreasing temperature of ASW to 15°C for depuration significantly increased the reductions of V. parahaemolyticus and V. vulnificus to 2.1 and 2.9 log MPN/g, respectively, after 48 h of process. However, depuration of oyster in ASW at 10 and 5°C were found less effective than at 15°C in reducing Vibrio in the Gulf oysters. An extended depuration with ASW at 15°C for 96 h was capable of achieving 2.6 and 3.3 log MPN/g of reductions of V. parahaemolyticus and V. vulnificus, respectively, in the Gulf oysters. Study of effects of frozen storage at -10, -23 and -30°C on reducing V. parahaemolyticus in raw half-shell Pacific oyster (Crassostrea gigas) found that the population of the bacterium decreased faster in oysters stored at -10 than at -23 or -30°C. Holding half-shell Pacific oyster at -10°C for three months or at -23°C for four months was capable of achieving a greater than 3-log (MPN/g) reduction of V. parahaemolyticus in the Pacific oyster. / Graduation date: 2008

Trafik utgör en stor föroreningskälla av tungmetaller i vägnära jordar och särskilt är det koppar (Cu), bly (Pb) och zink (Zn) som associeras med fordonstrafik. I ett historiskt perspektiv härrör blyutsläpp främst från bränsleförbränning, medan kopparemissioner (i första hand från slitage av bromsbelägg) och zinkutsläpp (från däck) från trafik står för så mycket som hälften av det urbana utsläppet av koppar och zink till omgivningen. Koppar-, bly- och zinkkoncentrationer i vägnära jord och sediment undersöktes inom avrinningsområdet för Grand River North West i Mauritius. Eftersom totalmetall utgör en dålig indikator på den mängd metall som finns potentiellt tillgänglig för biota användes extraktion med hjälp av 0.5 M HCl tillsammans med totalkoncentrationer. Den rumsliga variationen längsmed transekt vinkelrätt mot vägar undersöktes liksom variationen med djupet. Observerade kopparkoncentrationer var jämförbara med bakgrundsnivåer. Till skillnad från Cu var koncentrationer av Pb och Zn förhöjda i den omedelbara närheten till vägar med relativt stor trafikintensitet, men halterna minskade snabbt med avståndet. Resultat från platserna för jordreferenser visar på storskalig förorening av Pb på ön. Uppmätta kopparkoncentrationer kunde inte knytas till trafikens påverkan. Vid regn kan metaller som finns i förorenat vägdamm och förorenad jord övergå till löslig form, eller sköljas bort i partikulär form, och transporteras till närliggande vattendrag. I Mauritius är det här av speciell vikt eftersom flodsediment till slut kommer att deponeras i de känsliga kustområdena som omger ön. Dock tyder inte resultaten på förhöjda metallhalter i sediment nära de studerade vägarna. Även om erhållna resultat av Cu inte visar på någon förhöjning och zonen med hög förorening av Pb och Zn är relativt smal, är det angeläget att följa utvecklingen eftersom antalet fordon växer snabbt i Mauritius, vilket kan förändra dagens situation och ge upphov till större miljöpåverkan. För att undvika eventuella ekologiska skador är det därför av stor vikt att i fortsättningen övervaka situationen längs landets vägar. / Traffic has been identified as a significant heavy metal polluter of roadside soils, and copper (Cu), lead (Pb) and zinc (Zn) in particular are associated with road travel. In a historic perspective, the Pb contribution from anthropogenic sources to nature has predominantly been a result of fuel combustion. There are indications that Cu (mainly through braking system) and Zn (emissions from tires) released from traffic give rise to as much as half of the total urban contribution of copper and zinc to the environment. Concentrations of Cu, Pb and Zn in roadside soils and sediment have been determined at selected roads within the Grand River North West watershed in Mauritius. As total metal concentrations are not a suitable indicator of the metal concentrations that are potentially available to biota, metals extractable in 0.5 M HCl have been determined along with total concentrations. The spatial variation in metal concentration along soil transects perpendicular to roads were investigated, as was the variation with depth. Observed Pb and Zn concentrations exhibited elevated levels in topsoil in the immediate vicinity of roads with relatively large traffic densities, but the decrease in concentration with distance was rapid. Results from soil reference sites pointed to a large scale Pb pollution on the island. In comparison, observed Cu concentrations could not be assigned any influence from traffic at the selected study sites. In the event of rain, metals contained in polluted road dust and soil may be released into soluble form, or flushed from roadways as particulate matter, and transported to nearby water courses. In Mauritius, this is of particular importance as sediment in rivers eventually may be deposited in the sensitive coastal areas of the island. However, results do not indicate that there were any elevated levels of heavy metals in sediment close to roads that were investigated in this study. Although Cu concentrations in roadside soils did not show any enrichment and the zone of elevated Pb and Zn concentrations was not wide, there is a concern that the continuing rapid increase in the number of vehicles in Mauritius will change the situation, possibly resulting in greater impact on the surrounding environment. Hence, in order to avoid any ecological damage, it is desirable to continue monitoring the situation along highways in the country.

The cabin environment of a commercial aircraft, including cabin layout and the quality of air supply, is crucial to the airline operators. These aspects directly affect the passengers’ experience and willing to travel. This aim of this thesis is to design the cabin layout for flying wing aircraft as part of cabin environment work, followed by the air quality work, which is to understand what effect the ECS can have in terms of cabin air contamination. The project, initially, focuses on the cabin layout, including passenger cabin configuration, seat arrangement and its own size due to the top requirements, of a conventional aircraft and further into that of a flying wing aircraft. The cabin work in respect of aircraft conceptual design is discussed and conducted by comparing different design approaches. Before the evaluation of cabin air quality, an overall examination of the main ECS components involved in the contaminants access will be carried on and, therefore, attempt to discover how these components influence the property of the concerned contaminants. By case study in the B767 ECS, there are some comments and discussions regarding the relationship between the cabin air contaminations and the passing by ambient environment. The thesis ends up with a conclusion explaining whether or not the contaminated air enters the occupants’ compartments on aircraft and proposing some approaches and engineering solutions to the continue research.

The genotoxicity of energetic compounds (i.e., explosives) that are known to be present in contaminated soils at military training sites has not been extensively investigated. Thus, the Salmonella mutagenicity and Muta(TM)Mouse assays were employed as in vitro assays to examine the mutagenic activity of twelve explosive compounds, as well as three soil samples from Canadian Forces Base Petawawa. Salmonella analyses employed strains TA98 (frameshift mutations) and TA100 (base-pair substitution mutations), as well as the metabolically-enhanced YG1041 (TA98 background) and YG1042 (TA100 background), with and without exogenous metabolic activation (S9). For Salmonella analyses, the results indicate that ten of the explosive compounds were mutagenic, and consistently elicited direct-acting, base-pair substitution activity. All three soil samples were also observed to be mutagenic, eliciting direct-acting, frameshift activity. Mutagenic potencies were significantly higher on the metabolically-enhanced strains for all compounds and soil samples. For Muta(TM)Mouse analyses on FE1 cells, the results indicate that the majority of explosive compounds did not exhibit mutagenic activity. All three soil samples elicited significant positive responses (PET 1 and PET 3 without S9, and PET 2 with S9), and although there is some evidence of a concentration-related trend, the responses were weak. Correspondence of the mutagenic activity observed with the two assay systems, for both the explosive compounds and soil samples, was negligible. The differential response is likely due to differences in metabolic capacity between the two assay systems. Furthermore, it is likely that there are unidentified compounds present in these soil samples that are, at least in part, responsible for the observed mutagenic activity. Additional testing of other explosive compounds, as well as soil samples from other military training sites, using a variety of in vitro and in vivo assays, is warranted in order to reliably estimate mutagenic hazard and subsequently assess risk to human health.

Unlike municipal water supplies, provincial regulations do not require systematic testing of domestic well water, which may adversely impact local residents should contamination occur. Private wells are typically shallow relative to municipal wells, and thus, are particularly vulnerable to sources of surficial contamination if preferential recharge pathways such as natural fractures or faulty seals are present. In order to determine the relative importance of well seal integrity as a preferential pathway, a practical detection method was developed based on infiltrometry. This method successfully detected faulty well seals in a wide range of geological settings across Canada, including: Hobbema, Alberta; Lindsay, Ontario; and Chelsea, Québec. It was most successful in areas of minimal heterogeneity and where the surficial geology is composed of fine-grained sediments. The community of Chelsea (Québec) was also the primary study site to examine a range of factors affecting water quality including physical characteristics, faulty well seals, other anthropogenic activities and seasonality. Water samples were collected over a period of 14 months and analyzed for bacteria and major-ion chemistry. The results show that the consideration of physical features alone is not enough to predict vulnerability in the study area. Seasonal fluctuations in ionic concentrations (e.g. ionic strength, NO3-N and Cl-) and coliform bacteria are observed and result from disperse and rapid recharge events. Multivariate analysis techniques (e.g. principal components analysis and hierarchical cluster analysis) demonstrate that preferential recharge pathways and anthropogenic activities, such as domestic effluents affect the groundwater quality. The data and findings of this study were used to assist in the design of a probabilistic risk assessment model based on the Poisson distribution. This study demonstrates the complexity and the challenges related to bacterial contamination in drilled wells. In spite of these challenges, this analysis was useful as a baseline to assess the impact of anthropogenic activities, and may be used in future studies to assist municipalities in the evaluation and protection of groundwater supplies.

<p>Coal fired power plants are ubiquitous in the United States and most developed countries around the world, providing affordable electricity to consumers. In the US, approximately six hundred power plants generate 136 million tons of Coal Combustion Residuals (CCRs) annually, encompassing fly ash, bottom ash, and flue gas desulfurization materials. The range and blends of CCRs varies substantially across coal-fired plants and depends on a unique set of circumstances for each plant and coal source. Current U.S. regulations mandate the installation of advanced capture technologies to reduce atmospheric pollution, but do not address the transfer and storage, or the potential impacts to water resources. Thus improved air quality is traded for significant enrichments of contaminants in the solid waste and effluent discharged from power plants. </p><p>This work examines the geochemical and isotopic characteristics of CCRs, as well as potential environmental impacts from CCRs. This investigation looks at several different aspects of CCR and environmental interactions from 1) the immediate impacts of the 2008 TVA coal ash spill in Kingston, TN, 2) the long-term (18-month) exposure of the spilled ash in the Emory and Clinch rivers, 3) impacts on waterways in North Carolina that receive CCR effluent from coal fired power plants, and 4) examination of boron and strontium isotopes of CCRs from leaching experiments and their application as tracers in the environment of the TVA spill and NC waterways. These investigations have illuminated several conclusions, including contact of surface water with CCRs leach high concentrations of leachable CCR contaminants, such as As, Se, B, Sr, Mo, and V in the surface waters; the dilution effect is critical in determining the concentration of contaminants from the CCRs in surface water (both at the spill and in waterways receiving CCR effluent); recycling of trace elements (such as As) through adsorption/desorption can impact water quality; and elevated boron and strontium concentrations, in addition to their isotopes, can trace CCR effluent in the environment. Combining the geochemical behavior and isotopic characteristics provides a novel tool for the identification CCR effluents in the environment.</p> / Dissertation

Certains métaux peuvent agir comme perturbateurs endocriniens: les truites arc-en-ciel vivant dans les lacs contaminés au cadmium (Cd) ou au zinc (Zn) présentent une sécrétion cortisolique affaiblie en réponse au stress comparativement à celles non exposées. Des études in vitro ont révélé que le Cd et le Zn agissent directement sur la cellule adrénocorticale et nous avons démontré que le ¹⁰⁹Cd est transporté dans ces cellules par un système de transport spécifique. Comme la sécrétion cortisolique en réponse à l'adrénocorticotrophine (ACTH) impliquerait un influx de calcium (Ca), nous avons émis l'hypothèse que le Cd et le Zn inhiberaient cet influx. Les effets réciproques du Cd et du Ca, ainsi que du Zn, sur le transport de ¹⁰⁹Cd et de ⁴⁵Ca ont été caractérisés dans des cellules adrénocorticales isolées de truites d'élevage. Nous avons utilisé des milieux d'incubation inorganiques et avons analysé les résultats en terme de spéciation des métaux. Nos résultats démontrent l'existence d'un transport spécifique pour le ⁴⁵Ca. Des inhibitions réciproques entre le Cd et le Ca ont été observées en conditions optimisant les niveaux de Cd²⁺ comparativement aux chloro-complexes (CdCln²¯n). Le Zn inhibe préférentiellement le transport de ¹⁰⁹CdCln²¯n sans affecter l'accumulation de ⁴⁵Ca. Le Cd pourrait donc perturber la sécrétion de cortisol en diminuant la biodisponibilité du Ca dans les cellules stéroïdogéniques du tissu interrénal, mais il est peu probable que le Zn agisse ainsi. Le transport de ¹⁰⁹Cd étant inhibé par le Zn, ces deux métaux n'agiraient pas en synergie sur la fonction hormonale. Cette étude valide l'utilisation de cellules adrénocorticales isolées pour mieux comprendre la défaillance cortisolique observée chez les poissons vivant en écosystèmes contaminés. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Cadmium, Zinc, Calcium, Cortisol, Spéciation, Inhibition réciproque.

Ce mémoire de recherche s'attarde à la problématique du mercure et a été rendu possible grâce au Réseau collaboratif de recherche sur le mercure (COMERN) qui achève la dernière année de son mandat. Le mandat du COMERN était de décrire et de prédire le comportement de ce métal lourd dans les écosystèmes et son intégration à la chaîne alimentaire, de comprendre l'impact de la contamination par le mercure sur les ressources halieutiques, la faune et la santé humaine, et de collaborer avec les communautés à l'élaboration de perspectives de solutions. À l'exeption du mercure d'origine ocupationnel, la principale source de mercure pour le corps humain provient de la consommation de poissons. Plusieurs travaux de recherche portant sur la problématique du mercure (Hg), réalisés au sein et à l'extérieur du COMERN, ont tenté de trouver des facteurs clés permettant d'expliquer la variation des concentrations de Hg dans la chair des poissons issus de différentes populations ou de divers écosystèmes aquatiques. Cependant, la croissance, comme facteur biologique, a reçu peu d'attention des scientifiques. Récemment, une étude a démontré une relation inverse importante entre les concentrations de Hg dans la chair des poissons et leur taux de croissance, et ce pour douze populations de dorés jaunes au Québec. Dans la présente étude, nous étendons les observations à un grand nombre de populations de poissons et à trois différentes espèces. En effet, nous examinons la relation entre les concentrations de Hg dans la chair de 54 populations de dorés jaunes (Sander vitreus), 52 populations de grands brochets (Esox lucius) et 35 populations de touladis (Salvelinus namaycush) à travers le Québec. Pour ce faire, une importante base de données a été construite à partir de données recueillies d'Hydro-Québec, du Réseau collaboratif de recherche sur le mercure et du Ministère de l'environnement du Québec. Les concentrations de Hg en fonction de la longueur ont été décrites grâce à des régressions polynomiales avec variables indicatrices alors que les croissances des poissons (longueurs totales en fonction de l'âge) ont été représentées grâce au modèle de croissance de von Bertalanffy. Les concentrations de Hg estimées pour les dorés jaunes, les grands brochets et les touladis, à des longueurs standardisées respectives de 375 mm, 675 mm et 550 mm, ont ensuite été corrélées avec les âges estimés à cette longueur pour chacune des populations. Lorsqu'une corrélation existait entre les variables, une régression de modèle II, l'axe majeur réduit, a ensuite été effectuée pour décrire la relation. Les concentrations de Hg dans la chair étaient significativement corrélées avec les âges estimés pour les dorés jaunes (r²=0,549; p<0,001) et les grands brochets (r²=0,271, p<0,001, n=52 ; r²=0,471, p<0,001, n=49, alors qu'aucune corrélation entre ces variables n'a été observée pour les touladis (rpearson=0,1837;p<0,2907). Plusieurs travaux de recherche portant sur la problématique du mercure (Hg) ont tenté de trouver des facteurs clés permettant d'expliquer la variation des concentrations de ce métal dans la chair des poissons issus de différentes populations ou de divers écosystèmes aquatiques. Cependant, la croissance, comme facteur biologique, a reçu peu d'attention des scientifiques. Récemment, une étude a démontré une relation inverse importante entre les concentrations de Hg dans la chair des poissons et leur taux de croissance, et ce pour douze populations de dorés jaunes au Québec. Dans la présente étude, nous étendons les observations à un grand nombre de populations de poissons et à trois différentes espèces. Nous examinons la relation entre les concentrations de Hg dans la chair de 54 populations de dorés jaunes (Sander vitreus), 52 populations de grands brochets (Esox lucius) et 35 populations de touladis (Salvelinus namaycush) à travers le Québec. Une importante base de données a été construite à partir de données recueillies d'Hydro-Québec, du Réseau Collaboratif de Recherche sur le Mercure et du Ministère de l'Environnement du Québec. Les concentrations de Hg en fonction de la longueur ont été décrites grâce à des régressions polynomiales avec variables indicatrices alors que les croissances des poissons (longueurs totales en fonction de l'âge) ont été représentées grâce au modèle de croissance de von Bertalanffy. Les concentrations de Hg estimées pour les dorés jaunes, les grands brochets et les touladis, à des longueurs standardisées respectives de 375 mm, 675 mm et 550 mm, ont ensuite été corrélées avec les âges estimées à cette longueur pour chacune des populations. Lorsqu'une corrélation existait entre ces variables, une régression de modèle II, l'axe majeur réduit, a été effectuée pour décrire la relation. Les concentrations de Hg dans la chair étaient significativement corrélées avec les âges prédits pour les dorés jaunes (r²=0,549; p<0,001) et les grands brochets (r²=0,271 , p<0,001, n=52 ; r²=0,471, p<0,001, n=49), alors qu'aucune relation entre ces variables n'a été observée pour les touladis (rpearson= 0,1837; p<0,2907). Ces résultats suggèrent fortement que les populations de dorés jaunes et de grands brochets à croissance rapide auront des concentrations de Hg plus basses que les populations à croissance lentes. À l'inverse, pour les touladis de longueur standardisée, les concentrations de Hg dans la chair seraient indépendantes de leur taux de croissance. Il sera important de considérer les effets du taux de croissance sur les concentrations de Hg dans la chair des dorés jaunes et des grands brochets. En effet, dans le cadre de la prise de décision, et de la gestion des écosystèmes et des pêcheries, tout facteur pouvant affecter la croissance de ces espèces pourra de même altérer les concentrations de Hg dans leur chair. De plus, le taux de croissance, comme indicateur intégrateur de facteurs environnementaux multiples, pourra s'avérer un outil important lors d'études couvrant de larges territoires. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Mercure, Taux de croissance, Dorés jaunes, Grands brochets, Touladis, Québec.