▼ An outbreak of Middle East Respiratory Syndrome (MERS) among healthcare workers in Saudi Arabia in 2012 led to an investigation of hand-hygiene behaviors among healthcare professionals. Direct contact with patients is a major pathway for MERS, a droplet virus, which refers to a virus that lays on surfaces. This study investigated factors associated with respiratory disease transmission (e.g., MERS) in hospital settings among healthcare workers (i.e., physicians and nurses). I developed a 16-item checklist based on three sources: the CDC standards, the WHO Five Moments for Hand Hygiene, and Boyce and Pittet's (2002) guidelines of hand hygiene. I used those 16 items in both direct-observation and self-reported questionnaire formats. The checklist addressed three time frames of contact: before, during, and after contact with patients, devices, and surrounding surfaces. Hand-hygiene behaviors surrounding these time frames were assessed. The study also explored healthcare workers' beliefs about hygiene practices by comparing personal reports of hand hygiene assessed by questionnaire to observed actual hand-hygiene practices. The study was a cross-sectional research design and was conducted in the outpatient examination rooms and emergency departments of three hospitals (public, private, and military) in the Eastern region of Saudi Arabia. The total sample size included 87 physicians and nurses who were recruited while on duty during the researcher's observation periods. To provide clear results, I used two independent sample t-tests to test each of the 8 hypotheses. I found that no statistically significant differences were found among health-care workers when observing their behaviors of hand-hygiene practices. However, when using the self-reported questionnaire data, I found statistically significant differences between physicians' and nurses' hand-hygiene practices before, during, and after interacting with patients. Also, I found statistically significant differences between male and female hand-hygiene practices during interacting with patients, and I found statistically significant differences between health-care workers in public and military hospitals hand-hygiene practices during interacting with patients. For the primary hypothesis, I used Pearson correlation to determine the relationship between healthcare workers' reports of hand-hygiene practices, and observed healthcare workers behaviors of hand-hygiene practices. I found that no statistically significant correlation between the two data collection instruments. To provide a further analysis, a multivariate analysis of covariance (MANCOVA) was used to examine whether healthcare workers' hand-hygiene practices before, during, and after were different while controlling for their gender, department, and hospital type. I found that no statistically significant differences were found when observing the healthcare workers behaviors of hand-hygiene practices. However, when using the self-reported questionnaire data, I found that nurses and females reported better… Advisors/Committee Members: O'Rourke, Mary Kay (advisor), Reynolds, Kelly A. (committeemember), Verhougstraete, Marc (committeemember).

▼ Occupational exposures to hand-arm vibration and dust have been shown to have deleterious human health effects. Exposure to vibration from pneumatic tools can result in Hand-arm Vibration Syndrome (HAVS), which is a collection of vascular, sensorineural, and musculoskeletal disorders. Exposure to dust can result in a variety of adverse respiratory symptoms. The use of a low-frequency, high-magnitude sand rammer tool during mold-making processes at a foundry could result in significant exposure to these hazards, thus it is important to mitigate the associated risks in order to ensure worker safety. The goal of this study was to evaluate whether different pneumatic pressure levels and sand rammer types have an effect on reducing hand-arm vibration and dust exposures at a foundry. Vibration and dust measurements were obtained at three different pneumatic pressure levels (90 psi, 80 psi, 70 psi) and for three different sand rammer types (LM, SM, T). The primary concern of the study was reducing hand-arm vibration exposure. Measurements were taken in compliance with ISO 5349-1 resulting in frequency-weighted, root-mean-square (rms) acceleration values (m/s2). Significant differences in mean rms acceleration were observed across all pneumatic pressure levels and sand rammer types. At 90 psi the mean rms acceleration value was 25.53 m/s2, decreasing to 19.58 m/s2 at 80 psi, and further decreasing to 18.38 m/s2 at 70 psi. The mean rms acceleration values were 19.63 m/s2 for sand rammer LM, 21.46 m/s2 for SM, and 19.95 m/s2 for T. The results of this study indicate that reducing pneumatic pressure levels can reduce vibration exposure in the workplace when using low-frequency, high-magnitude tools. The results also indicate that the use of different sand rammer types produces differences in vibration exposure when tested across all pneumatic pressure levels. Dust measurements were taken concurrently with vibration measurements. The number of dust particles was counted for each pneumatic pressure level and sand rammer type. Overall, the mean particle count for the dust measurements was the highest at 90 psi (41,681) followed by 70 psi (33,514), and 80 psi (26,047). Sand rammer SM had the highest mean dust particle count at 35,732, followed by T at 34,460, and LM at 31, 382. The results indicate that lowering pneumatic pressure levels could potentially reduce dust exposure in the workplace when using a percussive tool such as a sand rammer. However, variability in the sampling conditions related to dust measurements weaken the association. Advisors/Committee Members: Stobbe, Terrence (advisor), Stobbe, Terrence (committeemember), Canales, Robert (committeemember), Griffin, Stephanie (committeemember).

▼  The accumulation of oxidative DNA damage has been hypothesized as a key event in chemical carcinogenesis. In this study, oxidative DNA damage was evaluated in the livers of rats exposed to vinyl chloride (VC), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-pentachlorobiphenyl (PCB 126), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) and 2,2',4,4',5,5'-Hexachlorobiphenyl (PCB153). Eight oxidative DNA adducts were measured, 8-hydroxyl-2'-deoxyguanosine (8-OHdG), 1, <i> N</i>⁶-etheno-2'-deoxyadenosine (ϵdA), <i> N</i>², 3-ϵG, 1, <i>N</i>²-etheno-2'-deoxyguanosine (1, <i>N</i>²-ϵdG), 3-(2'-deoxy-β-d-erythro-pentofuranosyl) pyrimido[1,2-α]purin-10(3<i>H</i>) (M₁dG), acrolein, crotonaldehyde and 4-HNE-derived dG adducts (assigned as AcrdG, CrdG, and 4-HNEdG respectively). ϵdA is one of the promutagenic DNA adducts formed by VC, which can also be formed by lipid peroxidation. In this study, both adult and weanling <i> Sprague-Dawley</i> rats were exposed to 1100 ppm (¹³C ₂)-VC for 1 week (6 h/day, 5 days/week). The results indicated that NA-ϵdA concentration did not show significant difference in the liver of adult and weanling rats after VC exposure. The distribution pattern of (¹³C₂)-ϵdA in liver, lung and kidney indicated that liver was the dominant target organ for VC toxicity in both adult and weanling rats. ROS-induced DNA adducts were detected in the liver of female intact, ovariectomized (OVX) and male <i>Sprague-Dawley</i> rats, including 8-OHdG, 1, <i>N</i>⁶-ϵdA, AcrdG, and CrdG. These animals were exposed to TCDD for 30 weeks after diethylnitrosamine (DEN) initiation. Induction of these adducts was consistently found in liver DNA of TCDD-treated intact female rats and 17β-estradiol (E₂) supplemented OVX female rats, but not detected in OVX rats without E ₂ supplement or male rats. These results further confirmed that the induction of these adducts occurs via a sex-specific and estrogen-dependent mechanism reported previously. Oxidative DNA damage was measured in liver DNA of female <i>Sprague-Dawley</i> rats following 53-week exposure of PHAHs, including PCB153, PCB126, TCDD, and the ternary mixture of TCDD, PCB126 and PeCDF. Increases of 8-OHdG, <i>N</i>², 3-ϵG and 1, <i>N</i>⁶-ϵdA were observed in PCB153 or PCB126 exposed animals. Significant increases of 1, <i> N</i>⁶-ϵdA were observed in all animals exposed to TCDD and the ternary mixture. Increases of 1, <i>N</i> ²-ϵdG, CrdG, AcrdG, 4-HNEdG and M1dG were detected in animals exposed to the ternary mixture, but not the TCDD treated rats compared to the control.

▼  <b>Background:</b> Asthma is a growing epidemic in the U.S. Obesity, and more recently metabolic syndrome, has been shown to be associated with increased prevalence of asthma morbidity prevalence. Air pollution exposure, meanwhile, is associated with increased risk of acute asthma exacerbation. However, it is unclear the extent to which co-morbidities, specifically obesity and metabolic syndrome, increase the risk of air pollution related asthma morbidity. <b>Methods:</b> Data for 105,914 unscheduled asthma hospital admissions with a primary diagnosis of asthma in New York City (NYC) during 2003–2006, were obtained from the New York State Department of Health Statewide Planning and Research Cooperative Survey. Daily monitored pollutant concentrations from NYC-area monitors were averaged to determine daily exposure estimates for pollutants, including fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃). A Poisson, generalized linear model was utilized to assess the association of these acute air pollution exposures with daily asthma hospital admissions among children (ages 1–17), adults (ages 18–64), and older adults (ages 65 and older). Analyses stratified by secondary diagnoses were then performed to determine whether obesity or metabolic syndrome co-morbid conditions modified the associations of air pollution and asthma hospital admissions in these age subpopulations. <b>Results:</b> Asthma hospital admissions among children, adults, and older adults were significantly associated with acute air pollutant exposures. Children with obesity had significantly higher risk ratios for asthma hospital admissions vs. children without obesity for associations with PM_2.5 and NO₂, especially among girls with obesity and during the warm season of the year. While the individual co-morbidities corresponding to metabolic syndrome (i.e., hypertension, diabetes, obesity, and hyperlipidemia) were not observed to significantly modify the associations of air pollutants and asthma hospital admissions, adults and older adults with multiple secondary diagnoses corresponding to metabolic syndrome had significantly higher risk ratios for asthma hospital admissions vs. those without metabolic syndrome. <b>Conclusions:</b> Obesity in children, and metabolic syndrome in adults, significantly increased the risk of air pollution related asthma hospital admissions in NYC. This information may enhance the consideration of susceptibility to air pollution in government policymaking, as well as inform physicians advising at-risk patients.

▼  Millions of people are exposed to arsenic in the United States and worldwide. Commonly found arsenic species in human urine are AsIII (arsenite), AsV (arsenate), MMA (monomethyl arsenic acid), DMA (dimethylarsinic acid) and AB (arsenobetaine). Evidence has shown that these species vary in toxicity, and since each of these metabolites can be detected through analysis, they have the potential to be used as biomarkers for human exposure. For human exposure assessments in areas that have naturally occurring arsenic contaminated sources, or those who live or work near contaminated environmental sites where arsenic has been used, it is important to fully understand what species of arsenic residents are being exposed to in order to grasp the risk of arsenic exposure specifically and in its entirety. Since it is difficult to determine direct human exposures, a swine model was used as a surrogate. Swine urine was collected from two different swine studies where animals were given non-toxic doses of arsenic contaminated soil and another group receiving a soluble reference dose using sodium arsenate for comparison. The urine samples from these studies were used to modify an arsenic speciation method using high-performance liquid chromatography and inductively coupled plasma mass spectrometry (LCICPMS). It is evident that when comparing the percent of arsenic species found in swine urine samples with what is found in humans a correlation can be made. There was a range of 64–74% DMA in swine samples for all test soils where a range of 60–75% DMA has been reported in human urine samples. This further illustrates the importance of arsenic speciation in swine urine since it does appear that it could correlate to human exposure. If proper measurement systems are utilized to quantify As species of health concern, dosed swine can be used to assess and predict human toxicological effects of arsenic exposure.

▼  Cause-specific mortality (CSM), among other global health estimates, has garnered prominence in the contemporary public health field. CSM has been associated with several factors, however, research comparing CSM for prefracking versus postfracking periods is sparse. Hydraulic fracturing or fracking is a technique of extracting oil and gas from deep underground. The purpose of this study was to evaluate the difference among mean CSM scores from 1975 through 2015 in the available cities and counties of residence in Colorado and to determine the impact of gender, marital status, county of residence, and city of residence on CSM scores (prefracking period 1975-1977 versus postfracking period 1999-2015) among adults aged 45-70 years. In this retrospective quantitative study, the socioecological model of health was used to analyze 73,251 cases obtained from the Colorado Department of Public Health and Environment. One-way analysis of variance and multiple regression were used to analyze data. Results showed that Denver County had a higher mean CSM score compared to other counties in Colorado. Regression results revealed a significant but weak association between CSM scores and gender, marital status, city of residence, and county of residence. If gender, marital status, and county of residence can be significant predictors of CSM, this information could have social change implications by influencing decisions regarding CSM and fracking.

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A research gap in the fields of exposure assessment and toxicology that remains unaddressed is the assimilation of experimental conditions to those of the real world human exposure. Currently, there is a lack of understanding of the properties of particles released by nano-enabled products (NEPs). Thus, we designed a multi-tiered methodology to physico-chemically, morphologically and toxicologically characterize engineered nanomaterials (ENMs) released from NEPs (i.e., toner powder). It is well established that printers emit nanoparticles during their operation; however, the physico-chemical and toxicological characterization of real world printer-emitted nanoparticles (PEPs) remains incomplete, hampering proper risk assessment efforts. For example, a number of studies estimating the potential adverse effects of PEPs used bulk toner particles as test particles rather than the actual particulate matter released by laser printers. Thus, the public health implications of exposure to PEPs remain largely unknown. For this project, a printer exposure generation system suitable for the subsequent physico-chemical, morphological, and toxicological characterization of PEPs was developed and used to assess the properties of particulate matter released from the use of commercially available laser printers. The system consists of a glovebox type environmental chamber for uninterrupted printer operation, real-time and time-integrated particle sampling instrumentation for size fractionation and sampling of PEPs and an exposure chamber for inhalation toxicological studies. Results from our extensive analysis show that laser printers emit up to 1,300,000 particles/cm3, most of which are nanoparticles. Further, we confirmed that a number of ENMs incorporated into toner formulations (e.g., silica, alumina, titania, ceria,) become airborne during printing. Both in vitro and in vivo toxicological evaluation showed PEPs are biologically reactive and may cause significant cytotoxicity, membrane integrity damage, reactive oxygen species production, pro-inflammatory cytokine release, angiogenesis, cytoskeletal and epigenetic changes as well as lung inflammation. This work highlights the importance of understanding life-cycle nano environmental health and safety implications of NEPs and assessing real world exposures and their associated toxicological properties rather than focusing on ‘‘raw’’ materials used in the synthesis of an NEP. Such analysis can be achieved for pollutants emitted by any NEP by employing the multi-tiered methodology described in this dissertation.

Environmental Health

Advisors/Committee Members: Demokritou, Philip xmlui.authority.confidence.description.cf_uncertain (advisor), Brain, Joseph (committee member), Kobzik, Lester (committee member), Godleski, John (committee member).

▼  This dissertation examines whether spatial measures of health determinants and health outcomes are being used appropriately and effectively to improve the health of marginalized populations in the United States. I concentrate on three spatial measures that have received significant policy and regulatory attention in California and nationally: access to healthful foods, climate change, and housing quality. I find that measures of these health determinants have both significant limitations and unrealized potential for addressing health disparities and promoting health equity. I define spatial triage as a process of using spatial data to screen or select place-based communities for targeted investments, policy action, and/or regulatory attention. Chapter 1 describes the historical context of spatial triage and how it relates to ongoing health equity research and policy. In Chapter 2, I evaluate spatial measures of community nutrition environments by comparing data from in-person store surveys against data from a commercial database. I find that stores in neighborhoods with higher population density or higher percentage of people of color have lower availability of healthful foods and that inaccuracies in commercial databases may produce biased measures of healthful food availability. Chapter 3 focuses on spatial measures of climate change vulnerability. I find that currently used spatial measures of "disadvantaged communities" ignore many important factors, such as community assets, region-specific risks, and occupation-based hazards that contribute to place-based vulnerability. I draw from examples of successful actions by community-based environmental justice organizations and reframe "disadvantaged" communities as sites of solutions where innovative programs are being used to simultaneously address climate mitigation, adaptation, and equity goals. In Chapter 4, I combine electronic health records, public housing locations, and census data to evaluate patterns of healthcare utilization and health outcomes for low-income children in San Francisco. I find that children who live in redeveloped public housing are less likely to have more than one acute care hospital visit within a year than children who live in older, traditional public housing. These results demonstrate how integrating patient-level data across hospitals and with data from other sectors can identify new types of place-based health disparities. Chapter 5 details recommendations for analytic, participatory, and cross-sector approaches to guide the development and implementation of more effective health equity research and policy.

▼  More than one billion people lack access to improved water supplies and even more lack access to safe water. Many household water treatment technologies have been documented to improve drinking water quality and reduce diarrheal disease. However, other technologies that are being used still lack rigorous evidence on ability to improve water quality and reduce diarrheal disease. One of these technologies is the biosand filter (BSF), an intermittently operated slow sand filter. It is estimated that more than 80,000 BSFs are in use world wide yet there is no rigorous evidence of their ability to reduce diarrheal disease and there is only limited evidence of their ability to improve drinking water. The purpose of this research was to examine the microbiological and health impact of the BSF in the laboratory and in the field. The laboratory research examined the ability of the BSF to reduce viruses and bacteria from water. The field research examined improvements in drinking water quality by the BSF in use in households and the ability of the BSF to reduce diarrheal disease. Based on the laboratory evidence, the BSF can achieve moderate to high reductions of bacteria 90-99% and moderate reductions of viruses (90%). The field study suggested moderate reductions of <i>E. coli</i> by the BSF in the field which was 80% on average yet it ranged 0-99.9%. The health impact portion of the field study found a 47% reduction in diarrheal disease in BSF users as compared to non-users. In addition, the health impact study found a weak association between increased contamination in drinking water as measured by <i>E. coli</i> and rates of diarrheal disease. The results from this research suggest that the biosand filter may be an effective way to improve drinking water quality and reduce diarrheal disease in the communities studied in Bonao, Dominican Republic.

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The widespread use of engineered nanomaterials (ENMs) in consumer products inevitably raises concern for potential exposure to ENMs released from such nano-enabled products (NEPs). It is therefore important to understand the scenarios and mechanisms by which ENMs are released over the NEP lifecycle causing exposure and potential environmental health implications. In this dissertation, I focus on understanding the fundamentals related to the incineration/thermal decomposition of industrially relevant NEPs, such as thermoplastics and coatings, widely used in many applications. The potential release of ENMs (used as nanofillers in NEPs) into the environment and the physicochemical, morphological (PCM) and toxicological properties of the released byproducts (released aerosol, residual ash and off-gases) are assessed. The role of NEP matrix composition, nanofiller type/size/mass-loading and thermal process conditions on the thermal decomposition behavior, release dynamics and byproduct PCM properties is investigated in detail. The potential cellular toxicological implications of the released aerosol are assessed and linked to PCM properties of the NEPs. Key findings suggest that inorganic (and catalytic) metal oxide nanofillers such as TiO2, Fe2O3 and CuO are more likely to be released into the aerosol compared to carbonaceous nanofillers (e.g., CNTs (carbon nanotubes)) and inert metalloid oxide nanofillers (e.g., SiO2). Moreover, majority of inorganic nanofillers are retained loosely in the residual ash as flaky clusters, prompting the concern for their subsequent release into the environment (due to weathering, leaching, etc.), whereas CNTs are completely combusted at the high temperatures (>800 °C). More importantly, in the case of released catalytic metal oxide nanofillers, due to their synergistic interactions with gaseous semi-volatile organic byproducts, carcinogenic polycyclic aromatic hydrocarbons (PAHs) could be formed and thus present a significant inhalation exposure hazard for incineration facility operators, firefighters and surrounding community. Furthermore, increased bioactivity and toxicity of the released aerosol compared to the control (no nanofiller) are also confirmed in cellular studies. Future studies should investigate effects of sequential lifecycle stresses such as weathering on thermal decomposition of NEPs. Additionally, environmental fate and transport of ENMs from residual ash should be performed to assess potential environmental health risks and develop mitigation strategies associated with incineration/thermal decomposition of NEPs.

engineered nanomaterials; nanofiller; host matrix; nano-enabled product; nano-enabled thermoplastic; nano-enabled coating; lifecycle; end-of-life; incineration; thermal decomposition; release; aerosol; inhalation exposure; residual ash; fate and transport; environmental health and safety implications

Advisors/Committee Members: Demokritou, Philip, Fredberg, Jeffrey, Brain, Joseph, Allen, Joseph, Wohlleben, Wendel.

▼ The United Nations estimates that the growing human population will reach approximately 9.6 billion by 2050. In order to accommodate the subsequently higher demand for food and related strain on resources, careful consideration of diet choice will be essential. This research evaluates the impact on greenhouse gas emissions from three different diets: vegan, vegetarian, and meat-based. This research is important is because greenhouse gas emissions from food are estimated at around 17% of total emissions. This study measures and evaluates all the steps in the food supply chain related to food production under conditions as they exist in the United States, using the Houston, Texas area as a base for the study. The intent of this research is to increase awareness of the global warming consequences of dietary food choices. My initial expected results—that vegan diets have the least emissions impact and meat-based diets have the highest—were confirmed via life cycle analysis. In this case study, vegan diets had a minimum contribution of 809 kg per person per year, followed closely by the vegetarian diet with 957 kg per person per year. However, a far higher greenhouse gas emission of 2,880 kg per person per year was calculated from the meat-based diet. The data from this study should help guide future food production decisions while also addressing the need for a reduction of greenhouse gas emissions through alternative food choices. Advisors/Committee Members: Leighton, Mark (committee member), Blinn, Stephen (committee member).

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The efficiencies of extraction with the [S,S]-stereoisomer of ethylenediaminedisuccinic acid ([S,S]-EDDS) on selected toxicants were investigated. A soil washing procedure to solubilize mixed contaminants, polycyclic aromatic hydrocarbon (PAH) compounds and heavy metals from soil, into an aqueous mobilizing solution containing 0.1 M EDDS-6% (V/V) Brij98 was optimized and evaluated. The optimized procedure with EDDS had mobilized a total of 101% of B[a]P burden from the soil after nine successive equilibrations with the same charge of mobilization aids (complexing reagent plus surfactant), which was 21% higher than analogous extractions with the equivalent quantity of EDTA and 28% higher than extractions in the absence of complexing reagent (surfactant Brij98 alone). In contrast to B[a]P, chrysene recovery was not affected appreciably by the presence of the EDDS reagent. Modelling of the extraction process for PAH compounds remaining within the soil revealed that B[a]P was extracted more efficiently in the presence of EDDS, i.e. the number of washes needed to reduce the initial concentration of B[a]P by half was less than the predicted number of washes in the presence of EDTA or Brij98, and the differences were significant at the 95% level of confidence. EDDS also had an appreciable influence on heavy metal exraction efficiency. Most analyte metals, (Al, As, Cd, Cr, Cu, Fe, Ni, Pb and Zn,) were extracted more efficiently in the presence of EDDS than in the presence of an equivalent quantity of EDTA or in the absence of complexing reagent. By contrast, the mobilization of Ca, Mg, and Mn by EDDS was decreased when compared with EDTA and/or surfactant alone.

Les efficacités d'extraction choisis avec le stéréoisomère [S,S] – de l'acide éthylènediaminedisuccinique ([S,S] - EDDS) sur des produits toxiques sélectionnées ont été étudiées. Un procédé de lavage a été optimisé et évalué pour solubiliser simultanément les composés aromatiques polycycliques de l'hydrocarbure (APH) et les métaux lourds du sol, dans une solution de mobilisation aqueuse contenant 0.1 M EDDS-6% (V/V) Brij98. Le procédé optimisé avec l'agent chélateur EDDS a mobilisé du sol un total de 101% de B [a] P après neuf extractions successifs. Comparativement, quand les expériences ont été réalisée avec EDTA ou sans l'adition d'agent complexant (seulement agent tensio-actif Brij 98), l'EDDS augment la efficacité un 21% par rapport à EDTA et 28% à la solution traitante en absence de agente complexant. Cependant, l'extraction de chrysène n'a pas été sensiblement affectée par la présence du réactif chélateur EDDS. La modélisation du processus d'extraction pour des composés organiques, APH, qui restent dans le sol a indiqué que B [a] P a été extraite plus efficacement en présence d'EDDS, c.-à-d. le nombre de lavages requis pour réduire la concentration initiale de B [a] P à la moitié était moins que le nombre prévu de lavages en présence d'EDTA ou de Brij98 seulement, et les différences étaient significatives au niveau de 95% de la confiance. L'EDDS a…

Advisors/Committee Members: William D Marshall (Internal/Supervisor).

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The rapid progression of an exotic haplotype of common reed (Phragmites australis (Cav.) Trin. ex Steud.) in North America is associated with a decline in the plant diversity of wetlands and possibly threatens native haplotypes of Phragmites australis. As prevention is a better strategy than control, a spatially-explicit approach was developed to predict the risk of invasion by the exotic P. australis and its potential impact on a native haplotype. Focusing on a protected wetland of Quebec, Canada where the two haplotypes occur, this study specifically aimed to: 1) compare and contrast the current spatial distribution of the two haplotypes in relation to landscape and land use/land cover variables, and 2) predict, using spatially-explicit models, the potential expansion patterns of the exotic and native P. australis. Results showed that the native P. australis was currently more frequent than the exotic P. australis. At this stage of invasion, native and exotic P. australis still occupied distinct parts of the territory, the native one being associated more with low marsh and areas of lesser human impacts, the exotic one being closer to roads or associated with drier land covers. Perturbations to the natural environment provided invasion foci for the exotic P. australis which is more tolerant to disturbances than the native one. The current distribution of invasion foci of exotic P. australis and its association to a broad range of conditions resulted in predicted expansion patterns where the cover of the exotic P. australis could potentially surpass the cover of the native P. australis within 10 years. This could lower the conservation value of the protected wetland and increase the competition with native colonies of P. australis where the two haplotypes intersect.

La progression d'un haplotype exotique du roseau commun (Phragmites australis (Cav.) Trin ex Steud.) en Amérique du nord réduit la diversité végétale des milieux humides en plus de menacer les haplotypes indigènes de Phragmites australis. La prévention étant plus efficace que le contrôle, une approche spatialement explicite visant à prédire les risques d'invasion par l'haplotype exotique et son impact sur un haplotype indigène a été développée. Cette étude conduite dans un marais protégé du Québec (Canada) visait à : 1) comparer et expliquer la distribution spatiale actuelle de ces deux haplotypes sur la base de leur relation à des variables de couverture/utilisation du sol et du paysage et 2) prédire à partir de modèles spatialement explicites les patrons d'expansion futures des haplotypes exotique et indigène de P. australis. À ce stade-ci de l'invasion, les haplotypes occupent des zones distinctes du territoire ; le P. australis indigène est associé aux bas marais et à des zones où l'influence anthropique est faible, tandis que le P. australis exotique se trouve près des routes et dans les milieux plus secs. Les perturbations au milieu naturel constituent des foyers d'invasion propices à l'haplotype exotique qui semble tolérer un éventail de…

Advisors/Committee Members: Sylvie de Blois (Supervisor).

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The welfare state continues to be eroded in the Global North. In Canada and the U.S., food banks are now one of the only systems of relief available. But in both countries, critics have accused food banks of being apolitical and thus taking away government responsibility to address inequality. The rise of food banks has been linked to the decline of the welfare state, leading to an assumption that an increase in public assistance can end the need for food banks. Yet little research exists that examines how other institutions such as the food industry drove food bank growth, or how food banks are politically active. The history of food banks in Canada presents an informative case study because the state was not directly involved in establishing food banks, thus allowing greater insight into the role of industry in the institutionalization of food banks and their political activity. Using environmental institutions and political ecology frameworks we conducted a literature review and interviews of experts, as well as a case study of one food bank. Our findings suggest that the factors leading to the existence of food banks cannot only be linked to cuts in welfare; rather, the influence of industrial decline and centralization of the food industry must also be taken into account, as well as social movements and the policy gap around food waste. Food banks can be political, using available resources as ‘fuel’ to challenge government failure. The case of Canadian food banks indicates that, to address inequality and food insecurity in the Global North, researchers and policy-makers should not only focus on welfare but need to tackle the cost-shifting practices of the food industry and work toward joined-up and nested food policy institutions. Further, food banks, or organizations that look like them, can help address rising food insecurity if they are provided with sufficient legal, political, and financial support.

L'État-providence continue de s’éroder dans le Nord global. Au Canada et aux États-Unis, les banques alimentaires constituent aujourd’hui un des seuls systèmes d’aide disponibles. Mais dans les deux pays, les critiques accusent les banques alimentaires d’être apolitiques et, par cela, d’atténuer la responsabilité des gouvernements d’aborder l’inégalité. a prolifération des banques alimentaires a été reliée au déclin de l’État-providence, ce qui laisse supposer que l’accroissement de l’aide publique pourrait éliminer le besoin des banques alimentaires. Pourtant, il existe peu de recherches qui examinent le rôle des autres institutions – telles que l’industrie alimentaire – dans la croissance des banques alimentaires, ou les activités politiques de celles-ci. ’histoire des banques alimentaires au Canada forme une étude de cas informative : l’État n’a pas joué de rôle direct dans l’établissement des banques alimentaires, ce qui permet un meilleur aperçu du rôle de l’industrie dans l’institutionnalisation des banques alimentaires, et de leur activité politique. Employant des institutions environnementales et…

Advisors/Committee Members: Nicolas Kosoy (Internal/Supervisor).

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This thesis represented the first attempt to investigate the effect of different tillage and crop residue management regimes on the genetic and functional diversity of soil Bacteria and Archaea in a corn agroecosystems in southern Québec. Soils were collected from a long-term (>15 year old) agricultural experiment with three tillage treatments- no-till, reduced tillage, and conventional tillage (mouldboard plowing) and two levels of residue input- with residues (corn roots, stems, and leaves) versus without residues (corn roots and little above ground residues). PCR-DGGE analysis of soil DNA extracts indicated that there was no significant difference of Bacterial and Archaeal communities in the different soil treatments. The potential for atrazine degradation was determine using a soil microcosm mineralization assay. The results of this experiment indicated that all the treatments had almost the same effect on atrazine mineralization. Functional gene microarray analysis of soil microorganisms affected by different treatments showed no clear difference among the different treatments. Microscopic analysis (CARD-FISH and DTAF) indicated that biomass and numbers of Bacterial and Archaeal were not significantly changed as a consequence of different treatments on agricultural soils in southern Québec. In conclusion, this study indicated that the different tillage practices (no-tillage, reduced tillage and conventional tillage) and crop residue managements (with residue and without residue) did not change soil microbial genetic/functional diversity, atrazine degradation, and microbial biomass.

La présente thèse constituait la première opportunité d'étudier l'effet de différentes techniques de labour et de gestion de résidus de plantes sur la diversité génétique et fonctionnelle bactérienne et archaenne des terres agricoles du sud du Québec consacrées à la culture du maïs. Des analyses PCR-DGGE d'extraits d'ADN du sol ont indiqué qu'il n'y avait aucune différence majeure entre les communautés microbiennes de bactéries et d'archaea, peu importe les différents traitements des sols. Des analyses de microréseaux de gènes fonctionnels des communautés de microorganismes de ces sols n'ont aussi montré aucune différence significative entre les différentes techniques d'entretien des sols utilisées. La capacité de dégradation de l'atrazine a été déterminée par analyse de minéralisation via un microcosme de sol. Les résultats de ce test ont indiqué que toutes les techniques de gestion des sols ont à peu près le même effet sur la minéralisation d'atrazine. Des analyses microscopiques (CARD-FISH et DTAF) ont indiqué que la biomasse du sol, ainsi que le nombre de bactéries et d'archaeas, ne changeaient pas de façon significative malgré les différentes techniques d'entretien des sols agricoles dans le sud du Québec. Pour conclure, cette étude a démontré que les différentes pratiques de labour (sans labour, pratique aératoire antiérosive et travail du sol classique) et de gestion de résidus de plantes (avec ou sans résidus) n'ont…

Advisors/Committee Members: Lyle Whyte (Supervisor).

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For psychrophilic anaerobic digestion systems, natural biota may provide sources of already adapted inoculum to reduce reactor start up time. The objective of the research was to test the inoculum potential of the microbial populations found in eight river sediments from the Montreal region, Canada, for the psychrophilic anaerobic digestion of swine manure. Also, to develop a simple theoretical method for quantification of acetoclastic methanogens in natural biota and validate using QRT-PCR technique. The anaerobic methanogenic populations of the sediments was quantified and characterized at 22 °C with specific methanogenic activity tests (SMA) using acetate and H2/CO2 as substrates. Then, biochemical methane potential (BMP) tests were conducted for 190 days at 10 °C using as substrate sterile swine manure, and as inoculums, the sediment with the highest methanogenic activity, fresh swine manure and sludge from an agro-food anaerobic mesophilic digester (AD sludge).

All eight sediments demonstrated pseudo-lag phases during the acetate SMA because of the low initial microbial populations. A visually significant correlation was observed between mgd.wt.cells/g sediment obtained from the predicted model and cell number/g sediment from the QRT-PCR results. During the H2/CO2 SMA, most sediments exhibited homoacetogenic activity out-competing that of the hydrogenotrophic methanogens. As compared to the most active sediment and swine manure and AD sludge inoculum presented approximately seven times more methanogenic activity at psychrophilic conditions. It also yielded 334 ml CH4/g CODin, which is almost twice as that of the active sediment. Further tests are required to optimize the process conditions, (i.e. loading rates, pH, etc.) in order keep the activity on its maximum.

Certaines biotes naturelles seraient en mesure de fournir aux systèmes de digestion anaérobie avec organismes psychrophiles des sources d'inoculum pré adaptés, réduisant ainsi le temps de démarrage du réacteur. L'objectif de cette étude fut d'évaluer le potentiel comme inoculum de populations microbiennes provenant de huit dépôts sédimentaires fluviaux de la région Montréalaise, pour la digestion anaérobie avec psychrophiles du lisier de porc. Il s'agirait aussi de développer une méthode théorique de base pour quantifier les méthanogènes acétoclastiques dans les biotes naturelles, et de la valider en utilisant une technique de transcription inverse suivie d'une PCR quantitatif en temps réel (QRT-PCR). Les populations anaérobies méthaniques des sédiments furent quantifiés et caractérisés à 22 °C grâce à des tests spécifiques d'activité méthanigène (SAM), utilisant l'acétate ou le H2/CO2 comme substrats. Des tests pour évaluer la production potentielle de méthane par voie biochimique (PPMB) se sont déroulés à 10 °C sur une durée de 190 jours, utilisant du lisier de porc stérile comme substrat, et comme inoculum soit (i) les sédiments ayant l'activité methanigène la plus élevée, (ii) du lisier de porc frais, ou (iii) de la boue de digesteur anaérobie…

Advisors/Committee Members: Serge R Guiot (Supervisor2), Suzelle Barrington (Supervisor1).

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There is a considerable interest in developing bioactive papers with active recognition and/or functional capabilities. Despite their distinct portability and practicability, direct sensing or recognition platform are often restricted to precisely aligned components or specific reactions. Motivated by photonic band gap materials, a non-specific color can be obtained by controlling ordered structures and further applied as an optical indicator for biosensing. In this work, polymerized colloidal crystal arrays (PCCAs) were for the first time integrated with a paper support. Since the continuous hydrogel phase can change and recover its volume by reversible hydration, the accompanying change in crystal lattice spacing imparts a visible color change due to Bragg diffraction. This material also possesses excellent salt anti-interference, extended cycling performance, and robust mechanical properties. Compared to other rigid substrates, only PCCAs on paper exhibit significant color change between the dry and hydrated states. These characteristics make paper-based polymerized colloidal crystal arrays (PB-PCCAs) promising for a new generation of sensing and anti-falsification applications. A future challenge is to develop optical changes that correspond to specific molecular recognition, perhaps by decorating the hydrogel or particles with functional groups.

Il y a un intérêt considérable dans le développement des papiers bioactifs avec des reconnaissances actives et/ou des capacités fonctionnelles. Malgré leur distinctions sur la portabilité et la praticabilité, la détection directe ou la plate-forme de reconnaissance sont souvent restreint avec composants précisément alignés ou aux réactions spécifiques. Motivé des matériaux la bande photonique écartée, une couleur non spécifiques peut être obtenue en contrôlant des structures ordonnés et d'un indicateur optique plus appliqué pour biosensing. Dans ce travail, les baies polymérisées du cristal colloïdal (PCCAs) ont été intégrée pour la première fois avec un support papier. Depuis la phase hydrogel continue peut modifier et restaurer son volume par hydratation réversible, le changement d'accompagnement en treillis de cristal en espace apporte une modification de la couleur visible en raison de la diffraction Bragg. Ce matériau possède également de l'excellente anti-interférence de sel, des performances étendues de cyclisme et des propriétés mécaniques robustes. Seul le PCCAs sur papier, par rapport aux autres substrats rigides, présentent des changements significatifs de couleur entre les états secs et hydratées. Ces caractéristiques rendent les baies polymérisées du cristal colloïdal sur papier (PB-PCCAs) prometteur pour une nouvelle génération d'applications de télédétection et anti-falsification. Un défi futur est de développer des modifications optiques qui correspondent à des reconnaissances de molécules spécifiques, peut-être par l'hydrogel ou particules avec les groupes fonctionnels de la décoration.

Advisors/Committee Members: Reghan James Hill (Internal/Supervisor), Theodorus G Van de Ven (Internal/Cosupervisor2).

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There is an increasing interest in environmental benefits provided by ecosystems. Among the wide range of environmental services, hydrological services are important not only because they affect all sectors of human behavior, but because they are closely tied to other services such as food supply and carbon sequestration. Investments in watershed management and the development of new market incentives are of increasing importance in both temperate and tropical regions. One of the mechanisms that have been strongly promoted is the adoption of Payment for Environmental Services (PES). In Latin America, most PES programs have been designed by estimating the provision of services using conventional knowledge about the direction and magnitude of the linkages between land use and hydrological variables. However, more often than not, we do not actually have measurements and data about the relationship between land use and the provision of many environmental services. Therefore, there is an increasing demand for estimating environmental services tradeoffs emerging from land use changes in order to enhance the bundle of ecosystem services available from a watershed, as well as methods to quantitatively evaluate these linkages. This thesis presents a conceptual framework for evaluating ecosystem functions and the application of an environmental index that combines environmental assessments and economic valuation. Three environmental services were evaluated: erosion control, discharge regulation and carbon sequestration. The 258 km2 of Las Ceibas watershed served as a case study, which is an agricultural basin located in Colombia, South America. Runoff and sediment processes were analyzed using the Soil and Water Assessment Tool (SWAT), and carbon sequestration potential using the CO2FIX model. I simulated three scenarios: (1) rotational grazing, (2) green manures and cover crops and (3) reforestation. The results indicate that reforestation, which mainly targeted the incr

Il y a un intérêt augmentant pour les avantages de l'environnement fournis par les écosystèmes. Parmi la large gamme de services de l'environnement, les services hydrologiques sont importants non seulement parce qu'ils affectent tous les secteurs de conduite humaine, mais parce qu'ils sont de près attachés à d'autres services comme les réserves d'aliments et la mise sous séquestre de carbone. Les investissements dans l'administration de ligne de partage des eaux et le développement de nouveaux stimulants du marché ont de l'importance augmentante dans les régions tant tempérées que tropicales. Un des mécanismes qui ont été fortement promus est l'adoption de Paiement pour les Services de L'environnement (PSE). En Amérique latine, la plupart des programmes PSE ont été conçus en estimant la disposition de services, la connaissance conventionnelle de la direction et de l'étendue des liaisons entre l'utilisation de terrain et les variables hydrologiques. Pourtant, plus fréquemment que pas, nous n'avons pas vraiment de mesures et de données du rapport entre…

Advisors/Committee Members: Raja Sengupta (Supervisor).

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As evidence piles up indicating that anthropogenic COâ‚‚ emissions are affecting the world's climate with potentially devastating results for its population, more attention is being directed towards means to reduce the quantities of COâ‚‚ being released. The production of energy through the burning of fossil fuels is the primary cause of these emissions, but is also vital to our current lifestyle and even survival. As such, it is essential that we develop reliable and economically viable renewable fuels to ensure that we have the energy needed to sustain our society into the future. To this end, it has been proposed that industrial flue gas containing large amounts of CO2 could be treated using algae. The algae would consume the carbon to grow, and could then be harvested to produce carbon neutral biofuels. Through photosynthesis, algae also produce oxygen as a by-product when growing. In the industrial algae carbon capture processes typically envisioned, this oxygen is produced in low concentrations and so is vented to the atmosphere as a waste product.In this study, we propose two scenarios in which an algae photobioreactor system could be developed to produce a valuable supply of oxygen enriched air, or even pure oxygen. Recovering and making use of this typically overlooked by-product has the potential to make industrial carbon capture and biofuel production more economically viable, and also has added environmental benefits. The key issue to consider for these proposed oxygen production systems is whether the algae themselves are capable of surviving, and more importantly growing, under the conditions they will be subjected to. The COâ‚‚ and oxygen concentrations found within these systems would be drastically higher than those of ambient air. We demonstrate that both these proposed oxygen production processes are in fact feasible. Further, that with the setup we designed, high concentrations of oxygen and COâ‚‚ may have a slight hindering effect on algae growth rates, but that neither completely inhibits growth. In addition, the oxygen production potential of three different algal species (Anabaena sp., Synechococcus sp., and Chlamydomonas reinhardtii) was found to be almost identical, suggesting that our proposed systems may be compatible with many different species of algae.

Il devient de plus en plus évident que les émissions anthropiques de COâ‚‚ ont une influence sur le climat de notre planète et que les conséquences pourraient en êtres dévastateurs pour la population. La production d'énergie par la combustion de combustibles fossiles est la cause principale de ces émissions, mais elle est aussi essentielle à notre mode de vie et même, notre survie. Il est donc nécessaire que nous développions des carburants renouvelables qui sont aussi économiquement viables pour assurer que nous avons l'énergie nécessaire pour soutenir notre société dans l'avenir. À cette fin, il a été proposé que les effluents des industries contenant de grandes quantités de COâ‚‚ pourraient êtres traités en utilisant des algues. …

Advisors/Committee Members: Parisa A Ariya (Internal/Supervisor).

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Produced water is the largest volume of waste produced during the recovery of oil from offshore oil and gas production platforms, and is discharged directly into the surrounding marine environment. Emerging evidence suggests that offshore produced water discharges impact biota at significant distances from the point of discharge. The objectives of this study were to characterize the marine bacterial and/or archaeal populations in and around the Hibernia, Terra Nova and Thebaud production platforms, to determine if changes in the bacterial community structure might be related to the influence of the produced water, and to develop molecular methods to monitor the bacterial community structure in seawater and to track the dispersion of produced water. The marine bacterial community structure remained relatively constant (with SAB > 70%) across large distances (up to 50 km away from the platforms) and throughout several years of sampling, suggesting that the produced water discharge did not have a detectable effect on the surrounding seawater. Bacteroidetes, Alpha-proteobacteria, and Gamma-proteobacteria were the most common and abundant phyla detected in the northwestern Atlantic Ocean. The only effect potentially related to the input of produced water was found on the sediment close to the Thebaud platform, suggesting that any impact might be restricted to a small area at the sediment level adjacent to the discharge. Firmicutes was the most common and dominant phylum detected in all three produced waters, represented principally by species of Thermoanaerobacter. Both species-specific detection methods (Q-PCR and nested-PCR) detected Thermoanaerobacter in surrounding seawater within 1000 m of the production platforms, but most of the Thermoanaerobacter were found at 100 m from Hibernia near the bottom of the water column, with only a small amount traveling into the upper water column. The properties of the produced water and existing modeling studies also support this dispersion pattern for produced water.This study provided the first characterization of the microbial diversity in and around the three major offshore oil and gas production platforms in Eastern Canada and developed new molecular methods to monitor and track the discharge of produced water.

L'eau de production représente le plus grand volume de déchets produits lors de la récupération du pétrole des plateformes pétrolières côtières, et cette eau est libérée directement dans le milieu marin avoisinant. Certaines évidences suggèrent que ces décharges d'eau de production auraient un impact sur la vie marine même à une distance considérable du point de décharge. Cette étude avait pour objectifs de caractériser les populations bactériennes et/ou archéennes marines aux abords des plateformes d'Hibernia, Terra Nova et de Thebaud, de déterminer si des changements dans la structure de la communauté procaryotique peuvent être reliés à l'influence de l'eau de production, de développer des outils moléculaires pour le suivi des communautés procaryotique dans…

Advisors/Committee Members: Charles William Greer (Supervisor2), Lyle Whyte (Supervisor1).

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Economic downturns are known to affect the management of natural resources and the environment. Although statistics and industry figures have revealed some impacts of the 2007-08 Global Financial Crisis (GFC), its dynamics and long term consequences for forest management, particularly in the context of South America, are unknown. Using qualitative research methods, combining grounded theory and case study analysis, this research aimed to better understand how the GFC impacted sustainable forest management (SFM) in Brazil through the experiences and perceptions of highly knowledgeable stakeholders. This was done with a view to providing a more holistic and integrated perspective on the GFC and to inform future policy and management processes. Findings from this study indicate that the GFC interacted with other political, social and environmental phenomena to produce both negative and positive impacts on SFM in Brazil. Negative impacts included: 1) restrained production of forest-based products; 2) declines in exports; and 3) reduced investments in non-market driven socio-environmental projects. Conversely, opportunities associated with the GFC included: 1) realizing competitive advantages in the plantation sector; 2) restrained deforestation in the Amazon Basin resulting from increased risk aversion and a decline in timber demand; and 3) support for third-party forest certification to maintain access to risk-averse markets. Traditional forest-based communities that often operate within informal economies were not seen as being heavily impacted by the GFC. This study represents a first step towards improving our knowledge on the relationships between economic downturns and sustainable forest management in Brazil.

Les ralentissements de l'activité économique sont connus pour affecter la gestion des resources naturelles. Bien que les statistiques et les données du domaine industriel ont revélé certains impacts de la Crise Globale Économique (CGE), ca dynamique et conséquences à long terme pour la gestion des forêts, en particulier en Amérique du Sud, sont inconnus. En utilisant des méthodes de recherche qualitatives, tout en combinant la théorie enracinée et l'étude de cas, cette recherche a pour objectif de comprendre comment la CGE a affecté la gestion soutenable des forêts au Brésil, au travers des expériences et perceptions de dépositaire bien informés. Ces méthodes ont été choisi pour donner une approche plus holistique et pour intégrer les perceptions sur la CGE dans le but d'informer les politiques futures et les procédures de gestions. Cette recherche montre que la CGE a interagit avec d'autre phenomene politique, sociales et environementales pour produire des effets positifs et negatifs sur la gestion soutenable des forêts au Brésil. Les impacts négatifs incluent: 1) une production resserrée de produits dérivés des forêts; 2) déclins des exports; et 3) investissements reduits dans les projets socio-économiques non visé au marche. Réciproquement, les avantages associés avec la CGE incluent: 1) réaliser des…

Advisors/Committee Members: Gordon Hickey (Supervisor).

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An increase in the prevalence of virulent and antimicrobial resistance genes-carrying bacteria in water systems could be a threat to public health. The overall objective of this study was to evaluate the impact of municipal wastewater treatment (biological and physicochemical) and disinfection (ultraviolet [UV] and peracetic acid [PAA]) processes on the prevalence of virulence and antimicrobial resistance genes (ARGs) in Escherichia coli. A total of 2,485 E. coli were genotyped using DNA microarrays and PCR/Bioplex assays.The findings of this study showed that both biological and physicochemical wastewater treatment processes reduced the prevalence of pathogenic E. coli. In municipal wastewaters, extraintestinal uropathogenic E. coli (UPEC) were the predominant E. coli pathotypes. The two treatment processes had differential effects on ARGs in E. coli. Biological treatment did not change the prevalence of ARG-carrying E. coli, but it increased the abundance of ARGs in the E. coli genome, while physicochemical treatment reduced both the prevalence of ARG-carrying E. coli and the frequency of ARGs in the E. coli genome.The disinfection experiments showed that the proportions of UPECs were reduced in all samples after UV and PAA treatments; however, UV and PAA had different effects on the prevalence of ARGs in potential UPECs. UV irradiation did not change the prevalence of ARGs in the surviving potential UPECs, while PAA treatment decreased the abundance of ARGs. A positive co-occurrence was found between the ARG and virulence genotypes. Overall, the results of this study suggest that wastewater treatment processes and disinfection reduced the abundance of virulence genes in E. coli; however, they had different effects on the prevalence of ARGs.

Une augmentation de la prévalence de bactéries pathogènes ou porteuses de gènes de résistance aux antimicrobiens dans les eaux pourraient être une menace pour la santé publique. L'objectif général de cette étude était d'évaluer l'impact des procédés de traitement des eaux usées municipales (biologiques et physico-chimiques) et des procédés de désinfection (ultraviolet [UV] et l'acide peracétique [APA]) sur la prévalence des gènes de résistance aux antimicrobiens (de l’acronyme anglais: ARG) et de la virulence d’Escherichia coli. Un total de 2 485 E. coli ont été génotypés à l'aide de micropuces ADN et d’essais PCR/Bioplex.Les conclusions de cette étude a montré que les deux procédés de traitement biologique et physico-chimique des eaux usées réduisaient la prévalence d’E. coli pathogène. Dans les eaux usées municipales, les souches d’E. coli extra-intestinal uropathogène (de l’acronyme anglais: UPEC) prédominait les pathotypes d'E. coli. Les deux traitements avaient des effets différents sur les ARG d’E. coli. Le traitement biologique n'a pas changé la prévalence des souches d’E. coli porteuses d’ARG, mais il a augmenté l'abondance des ARG dans le génome de ces souches, alors que les traitements physico-chimiques ont réduit la prévalence des souches porteuses d’ARG et la…

Advisors/Committee Members: Dominic Frigon (Supervisor2), Ronald Gehr (Supervisor1).

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In the face of global deforestation, and given the dependence of rural communities on forests for livelihoods, diverse and interconnected ecological and social drivers of land use change must be identified for successful conservation. The first chapter of this thesis focuses on land uses, analysing perceived influences on decision-making, and addressing historical factors and gendered perspectives as salient but poorly studied influences on the landscape. The case study was conducted in an indigenous communal land of eastern Panama that has experienced high deforestation since village settlement. We completed participatory mapping of lands, conducted semi-structured interviews and carried out participatory activities including wealth ranking, historical timeline creation and pebble scoring of historical land uses. Multivariate results derived from numerical ecology methods highlight the importance of historical factors like timing of settlement and place of origin on influencing the pasture-dominated communal landscape. We find gendered perspectives on landscape influences; men are more concerned with ecological influences and women with social-cultural. Traditional land use practices influence decision-making but ultimately decisions are guided by subsistence concerns. The second chapter provides a comparison of land uses and of the social-ecological factors that influence them in two communal lands that are similar in terms of known drivers of land use change but have differing land use trajectories. Spatial analysis of participatory maps using Geographic Information Systems (GIS) and remotely sensed Global Forest Watch (GFW) deforestation data illustrate the influence of topography as a key factor explaining differential forest cover. Additionally, qualitative analysis suggests the potential impact of historical factors on the landscape, including timber extraction, the presence of NGOs and scientific collaborators, and the strength of local leadership. We also compared GFW deforestation data to participatory data, to identify the usefulness of these new open source data as a local forest-monitoring tool. We find that, for applications on the ground, GFW data should be verified with local land users to ensure local relevance in areas with dynamic, complex mosaics of land uses. The research presented here illustrates the nexus of ecological and social influences on a landscape, as well as the potential for successful participatory engagement with locals and effective interdisciplinary science within a single study.

Étant donné la déforestation mondiale, et compte tenu de la dépendance des communautés rurales sur les forêts pour les moyens de subsistance, les facteurs interconnectés écologiques et sociaux de l'utilisation des terres doivent être identifiés pour une conservation efficace. Dans le premier chapitre de cette thèse, nous examinons les utilisations des terres, analysons les influences perçues sur la prise de décision, et étudions les facteurs historiques et les perspectives déterminées par le sexe, qui…

Advisors/Committee Members: Catherine Potvin (Internal/Supervisor).

▼ The present research contributes to the trend of critical analysis of Payments for Ecosystem Services (PES) by: a) developing a novel governance framework for ecosystem services in a watershed context; b) applying a methodological tool for assessing technical and social complexities for socio-ecological conflicts to a proposed PES scheme for watershed management; c) linking ecosystem services to discrete improvements in human well-being through a consideration of Amartya Sen’s ‘capabilities approach’; d) exposing the trade-offs implicit in targeting payment schemes for diverse objectives, and e) exploring the behavioural economics assumptions of PES in a context at the frontier of the free-market and exchange values for public goods and services. Few studies examining PES feasibility have taken an explicitly justice-oriented lens to considering fairness, equity for ensuring long-term negotiation outcomes. Two empirical studies are provided based upon a proposed PES scheme in the Shivapuri-Nagarjun National Park located in the Kathmandu Valley of Nepal. The first of these illustrates how market-based logic in spatially optimising payments fails to resonate with social institutions and values and inadvertently separates society from nature in a piecemeal fashion. Spatial interpolation according to household characteristics was employed using ArcGIS to map areas of low opportunity cost, ecological vulnerability and poverty. These maps were compared with the preferences, constraints, and informal institutions of upstream service providers to illustrate trade-offs between externally determined PES targeting designs and local legitimacy. It is argued that the mechanistic ‘puzzle-matching’ of targeting payments according to efficiency and effectiveness continues to treat society as separate from nature and risks reinforcing perceived inequities. The second study uses social multi-criteria evaluation as an alternative methodology for designing a number of PES and other management alternatives for Shivapuri-Nagarjun National Park. This method is based upon a deliberative negotiation of values, priorities and opportunities for improving individual and collective well-being and which do not allow for certain value sets to compensate others, but to expose the trade-offs inherent between equally legitimate perspectives.A final empirical study carried out at a pilot watershed PES programme in the Kyrgyz Republic examines the behavioural aspects of rational self-interest which characterise the assumed motivations underlying participation in PES schemes. Scholarship in the field of behavioural economics has illustrated how decentralised norm enforcement, norms of reciprocity, framing and image motivation may explain behaviour in social settings that override assumptions of purely rational and self-interested actors. In this study, different sets of incentives and framings of incentives are introduced to examine the extent to which they motivate participation in the maintenance and repair of collectively owned irrigation canals. The… Advisors/Committee Members: Jan Adamowski (Supervisor1), Nicolas Kosoy (Supervisor2).

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Agricultural activities alter landscapes to produce food and fiber and can pose a risk to the health of the soil, water and air, and impact biodiversity. The environmental impact of agriculture is largely influenced by the management practices implemented on farms. Beneficial management practices (BMPs) can help mitigate risk to the environment and improve the health of the soil, water, air and biodiversity. In order to develop effective agri-environmental policies and programs to promote environmental sustainability, decision-makers at all levels of government require science-based information on the environmental performance of agriculture, including information on practices being implemented on the farm. Information about BMP adoption in Canada has, until now, been largely fragmented and not widely available. In this study I developed a BMP Adoption Index, which is a reporting tool that measures the level BMP adoption in Canada and can be used to inform policy and program development. The BMP Adoption Index suggests that average adoption by both crop and livestock farmers across the country is in the medium range, with producers implementing more BMPs in areas where agriculture is a dominant land use. BMP Adoption across Canada does not appear to be motivated by a particular environmental issue or high environmental risk. Further investigation to identify the drivers of BMP adoption will enable decision makers to help farmers increase BMP adoption where they will be best able to mitigate the environmental risks of agriculture.

Les activités agricoles de production d'aliments et de fibres altèrent les paysages. Elles peuvent constituer un risque pour la qualité du sol, de l'eau et de l'air, et avoir des répercussions sur la biodiversité. L'impact de l'agriculture sur l'environnement est en grande partie dû aux pratiques de gestion mises en Âœuvre dans les exploitations agricoles. Les pratiques de gestion bénéfiques (PGB) peuvent aider à réduire le risque pour l'environnement, améliorer la qualité du sol, de l'eau et de l'air et préserver la biodiversité. Afin de concevoir des politiques et des programmes agroenvironnementaux efficaces pour promouvoir la durabilité environnementale, les décideurs de tous les ordres de gouvernement ont besoin de renseignements fondés sur la science concernant la performance environnementale de l'agriculture, y compris des renseignements sur les pratiques mises en Âœuvre à la ferme. Les renseignements concernant l'adoption des PGB au Canada ont été transmis de manière fragmentée jusqu'à aujourd'hui, et n'ont jamais été mis à la disposition du grand public. Dans le cadre de cette étude, j'ai conçu un indice d'adoption des PGB ; un outil de présentation de données qui mesure le niveau d'adoption des PGB au Canada et qui peut être utilisé pour éclairer l'élaboration des politiques et des programmes. L'indice d'adoption des PGB donne à penser qu'en général, l'adoption par les cultivateurs et les éleveurs de bétail du Canada se situe dans la fourchette moyenne, les producteurs mettant en…

Advisors/Committee Members: Elena Bennett (Supervisor).

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Energy is one of the biggest concerns of today's society, because of the rapid depletion of the world's fossil fuel reserves. Efficient energy technologies and renewable energy sources must therefore be developed and implemented. With a 5% share of the total energy consumption, agriculture can benefit from such developments. To preheat cold and fresh ventilation air for livestock barns, solar collectors are one of the promising renewable energy sources to reduce fossil fuel used in heating. Besides identifying energy saving strategies, the objective of the present project was to evaluate the performance of a specific type of solar air pre-heaters consisting of unprotected black corrugated metal sheeting with 1% perforation, installed over the barn fresh air inlets facing south. In this experiment, the two identically built commercial broilers barns were located in St-Jean-Baptiste, 40 km east of Montreal, Canada at 45.5 ° latitude. Each barn offered three floors with a capacity of 6500 broilers/floor, and 73.65 m2 of solar air pre-heaters for a total of 221 m2/barn. From November 2007 to March 2009 the project monitored inlet, inside and outside air conditions, ventilation rate and solar energy recovery and, from this data, conducted energy balance analyses. Measured efficiencies in recovering solar radiation varied from 65% to 20% depending on wind velocity and produced an annual return on investment of 4.7%. Air temperature stratification inside each room was responsible for the loss of 25 and 15% in heater energy and recovered solar energy, respectively. Although reducing heating load, the solar air pre-heaters had no impact on livestock performance because of limited effect on ventilation rate. The monitoring of ambient air temperature and relative humidity was complicated by air temperature stratification. Furthermore, the proper monitoring of ventilation rates requires the installation of electromagnetic sensors on all exhaust fans. The pyranometers used i

L'énergie est l'une des plus grandes préoccupations de la société d'aujourd'hui en raison de l'épuisement rapide des réserves de combustibles fossiles dans le monde. Des technologies nouvelles et plus efficaces ainsi que des sources d'énergies renouvelables doivent par conséquent être développées et implantées. Avec une part de 5% de la consommation mondiale d'énergie, l'agriculture peut bénéficier de ces développements. Pour préchauffer l'air frais entrant par la ventilation des bâtiments d'animaux d'élevage, les capteurs solaires sont une des sources d'énergies renouvelables prometteuses afin de réduire la consommation d'énergie en chauffage. Outre l'identification des stratégies d'économie d'énergie, l'objectif de ce projet était d'évaluer la performance d'un type spécifique de capteurs solaires pour le préchauffage de l'air constitué d'un revêtement métallique noir, ondulé et non protégé du vent ayant 1% de sa surface en perforation. Ce revêtement était installé aux prises d'air d'un bâtiment dans la direction la plus méridionale possible. Les deux…

Advisors/Committee Members: Suzelle Barrington (Supervisor).

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Risk assessors are often asked to estimate the concentration of a trace element in the edible part of a plant based on soil properties. More accurate models are needed to better assess the risks associated with the consumption of plants growing in contaminated soils. Although the importance of different soil physico-chemical properties on trace element bioavailability is recognized, the effect of plant physiological processes have received less attention. This thesis reports efforts to integrate soil physico-chemical properties and plant physiological factors in the modeling of trace element uptake by plants and provides a reflection on the assessment of the risks associated with urban gardening on the Island of Montréal. Chapter 2 presents and discusses the results of a field experiment in 19 urban gardens in Montréal. Our results suggest that, although some gardens showed significant contamination, the vegetables grown in all of the gardens we tested were safe for consumption. Our analysis also suggests that the model and methods used by the direction of public health of Montréal in 2007 in their risk assessment greatly overestimated trace element concentrations in vegetables and constituted a weak scientific basis for decision-making. To improve the accuracy of the models used by risk assessors, two approaches were developed. In Chapter 3, the effect of transpiration rate, a process thought to affect trace element uptake and accumulation by plants, was tested in a controlled environment experiment. Our data suggest that, although an effect is observed, its magnitude is not as high as expected, especially when trace element concentrations in the above ground plant parts are concerned. Hence, the integration of transpiration rate into trace element uptake modeling may not constitute a significant improvement. In Chapter 4, data from five experiments are analyzed and models are developed to predict the concentration of 15 trace elements in 13 plant tissues as a function of total trace element concentrations in soil and key soil physico-chemical properties such as pH, soil organic matter (SOM), and cation exchange capacity (CEC). Our results suggest that CEC and pH are the soil properties that best correlate with trace element bioavailability for a wide range of elements and plants.

En évaluation de risque environnemental, il est souvent nécessaire d'estimer la concentration d'un contaminant dans les parties comestibles d'une plante à partir d'une analyse de sol. Il est essentiel de développer de meilleurs modèles prédictifs afin d'identifier adéquatement les risques associés à la culture de plantes dans des sols contaminés. Si l'importance des propriétés physico-chimiques du sol sur la biodisponibilité des élément-traces est bien documentée, l'effet des processus physiologiques sur leur accumulation dans les plantes n'a reçu que peu d'attention. Ce mémoire propose une réflexion sur l'évaluation des risques associés à l'agriculture urbaine à Montréal et expose les résultats de recherches visant à intégrer des…

Advisors/Committee Members: William H Hendershot (Supervisor).

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Polybrominated diphenyl ethers (PBDEs) are one type of brominated flame retardant commonly used in industrial and domestic items. Their lipophilic and persistent properties and global occurrence in wildlife are cause for concern, especially for those at the top of the food chain, such as raptorial birds. This study consisted of dietary or in ovo exposure of captive American kestrels (Falco sparverius) to one of two environmentally relevant levels (high and low exposures) of the pentaBDE mixture, DE-71. Maternal retinol levels were reduced in the low-exposure group after three weeks of exposure and were associated with fewer hatchlings and increasing in ovo BDE-17 concentrations. The in ovo exposure affected the retinol levels of nestling kestrels and altered their thyroid hormones and the functioning of their thyroid system. These parameters were associated with in ovo concentrations of various BDE congeners, body mass, and feather growth. These findings are consistent with the reduced reproductive success of these birds and the altered growth of their young.

Les éthers de diphényle polybromé (EDPB) sont un type d'ignifuge bromé couramment utilisé dans les produits industriels et domestiques. Leurs propriétés lipophiles et persistantes ainsi que leur distribution mondiale dans la faune sont causes de préoccupation, surtout à l'endroit des espèces qui occupent le sommet de la chaîne alimentaire, tels que les oiseaux de proie. Cette étude comporta une exposition par voie alimentaire ou ovo de crécerelles d'Amérique captives (Falco sparverius) à l'un parmi deux niveaux écologiquement pertinents (expositions haute et faible) du mélange pentaEDB, DE-71. Les niveaux maternels de rétinol ont été réduits dans le groupe à faible exposition après trois semaines d'exposition et ont été associés à une réduction dans le nombre de poussins et à des concentrations ovo croissantes de EDB-17. L'exposition ovo a affecté les niveaux de rétinol chez les crécerelles juvéniles et a altéré leurs hormones thyroïdiennes et le fonctionnement du système thyroïdien. Ces paramètres ont été associés aux concentrations ovo de divers congénères EDB, à la masse corporelle et à la croissance des plumes. Ces résultats sont en accord avec le succès reproducteur réduit de ces oiseaux et l'altération de la croissance chez leur progéniture.

Advisors/Committee Members: David M Bird (Internal/Supervisor), Kimberley Fernie (Internal/Cosupervisor2).

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The emergence of Integrated Water Resource Management (IWRM) coincides with the growth of watershed associations in Québec. As a collective entity of stakeholders, these watershed associations use collaborative efforts to achieve IWRM. First Nations are often cited as priority stakeholders. Despite this 'priority' recognition, First Nations are rarely present in this new paradigm shift in water management. This is the case in Québec's Outaouais and Chateauguay watersheds. However, identifying First Nation capacity strengths and limitations provides a greater understanding as to their absence from IWRM participation. First Nation capacity to practice IWRM requires greater research. The purpose of this study is to apply an analytical framework to assess the overall capacity of two First Nation communities to practice IWRM in the province of Québec. The capacities of Kitigan Zibi and Kahnawà:ke First Nations were evaluated with respect to actor networks, information management, human resources, and technical, financial, and institutional dimensions. This study recommends that future Québec IWRM initiatives with First Nation collaboration need to be directed towards strengthening actor networks capacity and understanding the complexity of First Nation perspectives. In addition, study results indicate First Nations with limited financial capacity will experience reduced actor networks, information management, human resources, and technical capacity.

Au Québec, l'apparition du concept de Gestion Intégrée des Ressources en Eau (GIRE) coïncide avec la croissance des comités de bassins versants. En tant qu'entité collective et multi-actrice, ces comités de bassins versant s'appuient sur des efforts de collaboration pour parvenir à gérer leurs ressources en eau de façon intégrée. Les Premières Nations sont souvent citées comme des acteurs prioritaires dans l'application de la GIRE. Pourtant, elles sont rarement présentes dans ce changement de paradigme de gestion de l'eau. C'est le cas pour les bassins des rivières Outaouais et Châteauguay au Québec. Cependant, identifier les forces et faiblesses du pouvoir d'action des Premières Nations permet de mieux comprendre leur absence dans ce nouveau mode de gestion des eaux. C'est pourquoi les recherches sur le pouvoir d'action des Premières Nations ont besoin d'être approfondies. L'objectif de cette étude est d'établir le cadre analytique permettant d'évaluer la capacité globale de deux communautés de Premières Nations à mettre en pratique le GIRE dans la province de Québec. Les Premières Nations Kitigan Zibi et Kahnawake furent étudiées en tenant compte des aspects tel que les réseaux d'acteurs, la gestion de l'information, les ressources humaines, et les capacités financières, techniques et de gouvernance. Un cadre analytique fut développé pour évaluer chacun de ces aspects. Cette étude recommande que les initiatives futures de collaboration avec les Premières Nations soient orientées vers le renforcement du réseau d'acteurs et, vers la compréhension de la complexité…

Advisors/Committee Members: Jan Adamowski (Internal/Supervisor).

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Forest ecosystems in southern Quebec have been exposed to high levels of atmospheric acid deposition for many decades. American beech (Fagus grandifolia Ehrh.), an acid-tolerant species, is increasing in abundance in the sugar maple (Acer saccharum Marsh.) dominated forest of southern Quebec. I therefore hypothesized that beech is better adapted than sugar maple to access the soil Ca in these forests. In my thesis, I partitioned the source of soil Ca by horizon/depth for beech foliage at two sites of contrasting soil fertility using a Ca/Sr approach. The discrimination of Ca over Sr by beech was determined by sampling seedlings and their extended rhizosphere (n = 40) on sites with large differences in Ca and Sr supply, as well as Ca/Sr ratios. With the discrimination function determined (R2=0.5, p<0.05), a study was conducted to determine if leaf Ca/Sr was independent of the height of sampling. Trees were sampled at three different heights (3, 6, and 13 m). Leaf Ca/Sr was found to be independent of the height of sampling in both sugar maple and beech (p = 0.67). Mature beech trees were sampled on a poor sandy ridge in the Morgan Arboretum (n = 22) and in the Hermine watershed in the Lower Laurentians (n =18). At both sites, soils were acidic with decreasing fertility with depth and low Ca/Al ratios. Beech was found to take up soil Ca primarily from the F horizon on both sites (> 60%) and the contribution from deeper soil horizons generally decreased with depth. The more superficial uptake of Ca by beech compared to sugar maple could provide it with a competitive advantage in terms of nutrition which could explain in part its increasing dominance in the Quebec landscape.

La forêt du sud du Québec reçoit depuis plusieurs décennies des niveaux de déposition acide élevés. Le hêtre d'Amérique (Fagus grandifolia Ehrh.), une espèce adapté aux conditions de sol acide, a gagné en abondance dans la forêt du sud du Québec qui est dominé par l'érable à sucre (Acer saccharum Marsh.). J'ai donc émis l'hypothèse que le hêtre est mieux adapté que l'érable à sucre pour accéder au Ca du sol dans ces forêts. Dans ma thèse, j'ai partitionné la source de Ca du sol des feuilles du hêtre par horizon/profondeur à deux stations de fertilité différente au moyen de l'approche des ratios de Ca/Sr. La discrimination entre le Ca et le Sr par le hêtre a été déterminé en échantillonnant des semis avec leur rhizosphère (n = 40) sur des stations présentant des niveaux de Ca, Sr et Ca/Sr très différents. Une fois la fonction de discrimination établie (R2=0.5, p<0.05), une étude a été faite pour déterminer si les ratios de Ca/Sr dans les feuilles variaient avec la hauteur d'échantillonnage. Les arbres ont été échantillonnés à trois hauteurs (3, 6 et 13 m). Les ratios de Ca/Sr des feuilles s'est avéré indépendant de la hauteur d'échantillonnage chez l'érable à sucre et le hêtre (p = 0.67). Des hêtres matures ont ensuite été échantillonnés sur un sol sableux de l'Arboretum Morgan (n = 22) et dans le bassin de l'Hermine dans les Laurentides…

Advisors/Committee Members: Benoit Cote (Supervisor).