Selective serotonin reuptake inhibitors (SSRIs), like fluoxetine, are widely used to treat depressive disorders during pregnancy. These antidepressants reach water reservoirs through sewage treatment facilities and expose the aquatic vertebrates, including fish. It has been shown that early-life exposure to fluoxetine could disrupt the normal function of the stress axis by decreasing the level of circulating glucocorticoids in humans, rodents, and teleosts. Our lab recently showed that early life exposure to fluoxetine resulted in transgenerational hyporcortisolism and altered exploratory behaviour in adult male zebrafish and their descendant male adults for at least three generations. In the current study, we used a stress-responsive transgenic zebrafish line (SR4G) that expresses green fluorescence protein (eGFP) under the control of six consecutive glucocorticoid response elements. The effects of developmental exposure to fluoxetine on the transcriptional profiles of genes in the larval head and male adult telencephalon and hypothalamus were analysed using high throughput RNA sequencing. We also assessed the potential of eGFP mRNA to evaluate blunted stress response as an alternative to cortisol immunoassay measurements. The effects of bisphenol A, vinclozolin and fluoxetine were ytested in the SR4G line. Developmental exposure to fluoxetine resulted in a life-long dysregulation of pathways involved in nervous system development, stress response, and lipid metabolism in both larvae and adult zebrafish. Numerous differentially expressed genes in zebrafish are orthologous to genes in Homo sapiens linked the development of the major depressive disorder and epigenetics regulation and include bdnf, trkb, npas4, per1, per2, dnmt3a, adarb1, adaeb2, hdac4, hdac5, hdac8, and atf2. It is suggested that the dysregulation of the primary transcription regulators of circadian rhythm (clocka) and stress response (nr3c1), amongst others, were the potential drivers of the observed life-long effects. Furthermore, we report on a significant positive linear correlation between cortisol levels and eGFP mRNA levels in SR4G transgenic zebrafish larvae (R2> 0.9). Random forest and logistic regression models trained by eGFP mRNA levels both correctly predicted the blunted stress response. The negative predictive value (NPV) for both models was 100%. Models based on the mRNA levels of 11 genes associated with neurogenesis, stress response and depression resulted in a similar 100% NPV. These findings provide evidence for a life-long effect of developmental exposure to fluoxetine. This study also provides a proof-of-concept for an in vivo biomonitoring assay to screen chemicals for their stress-disrupting potential.

Microplastics are present in municipal wastewater treatment plant (WWTP) effluents; however, it is unclear whether these contaminants are ingested by biota living downstream of these outfalls. This study examined whether microplastic levels in caged biota, resident fish, and environmental samples were elevated near the Waterloo and Kitchener WWTP outfalls along the Grand River in the fall of 2019. Amphipods (Hyalella azteca), fluted-shell mussels (Lasmigona costata), and rainbow trout (Oncorhynchus mykiss) were caged at one upstream reference site and two impacted sites downstream of the Kitchener WWTP for 14 (amphipods and trout) or 28 (mussels) days. Rainbow darter (Etheostoma caeruleum) were collected using a backpack electrofisher from 10 sites up and downstream of both the Kitchener and Waterloo WWTPs, along with surface water and sediment samples. Whole body Hyalella, fish digestive tracts, and fluted-shell mussel tissues (hemolymph, digestive glands, and gills) were digested in 20% potassium hydroxide. Environmental samples were processed using filtration and density separation, then visual identification of microplastics was done. Elevated particle counts were found in rainbow trout digestive tracts at the Kitchener outfall site, compared to the upstream reference and downstream farfield sites. Additionally, particle concentrations in sediment were significantly higher at the Waterloo outfall, compared to all other sites (except for one upstream location). However, whole Hyalella, fluted-shell mussel tissues (hemolymph, digestive glands, and gills), digestive tracts of rainbow darter, and surface waters did not show elevated counts downstream of these discharges. Across all samples, fibers were the most common morphology, and blue and clear particles were prevalent in samples collected near WWTPs. Overall, these findings suggest that the Kitchener and Waterloo WWTPs could be important sources of particles to the Grand River, adding to our understanding of the fate of this contaminant in freshwater ecosystems. / Thesis / Master of Science (MSc)

MSc Thesis - The effect of wastewater effluent on the gut microbiome of rainbow darter / The microbiome plays an important role in host physiology and can be influenced by species, diet, and environment. Municipal wastewater effluent contains a mixture of chemicals including antibiotics and antimicrobials that may affect the gut microbiome of fish living downstream of these discharges. Thus, this study examines the effect of wastewater treatment plant (WWTP) effluent on the gut microbiome of wild rainbow darter (Etheostoma cearuleum), and examines how the gut microbiome of wild fish changes in the lab. Fish were collected from sites upstream and downstream of 2 major WWTPs along the central Grand River and gut contents were aseptically sampled. After extracting gDNA, nested PCR of the V3-V4 region of the 16S rRNA gene, and Illumina sequencing were performed. The gut microbiome of exposed fish had increased bacterial diversity and was dominated by Proteobacteria, which has been linked to altered health outcomes in mammals. Next, rainbow darters were collected from a reference site on the Grand River. Fish were sampled in the field, after a 14 day lab acclimation, and after a 28 day exposure to environmental stressors (WWTP effluent or triclosan, an antimicrobial found in WWTP effluent). Surprisingly, there were no changes in the microbiome after exposure to environmental stressors. Major changes were observed between the field and laboratory fish suggesting that environment and diet are important factors influencing the gut microbiome. Changes in the gut microbiome continued up to 42 days in the lab, indicating longer acclimation periods may be needed. This study showed that effluents altered the gut microbiome of fish in the field, but not in the laboratory for unknown reasons. Laboratory studies indicated that transitioning to a new environment may require greater than 14 days before achieving a stable microbiome. / Thesis / Master of Science (MSc) / Wastewater is the largest source of pollution affecting Canada’s aquatic ecosystems; effluents contain antibiotics and antimicrobials that can affect fish and other aquatic life. The gut microbiome of fish is influenced by host species, its diet, and the environment, and thus contaminants released via wastewater effluents may alter the gut microbiome of fishes in receiving waters. This study found that the gut microbiota of rainbow darter fish exposed to wastewater effluents in the central Grand River (Waterloo/Kitchener, Ontario) were dominated by Proteobacteria and had increased diversity. Wild fish transitioned to the lab were dominated by Firmicutes and had decreased bacterial diversity in the gut compared to those in the wild. Altogether, these results suggest that wild fish exposed to wastewater effluents had altered gut microbiomes; transitions to new environments and laboratory acclimation periods are important considerations when studying the fish gut microbiome.

This research expands on recent sociological studies which maintain that environmental contaminants in America are disproportionately placed in neighborhoods inhabited by minorities and the poor. Prior studies have focused on the predictor variables which identify areas of contamination near residential neighborhoods, yet fail to explore the socio-political and historical factors which contribute to these phenomena. The Environmental Protection Agency's Toxic Release Inventory 1990 database, the Texas Natural Resource Conservation Commission's Annual Report of the Hazardous and Solid Waste Program for 1992, and the U.S. Census Bureau's 1990 Census Data for Dallas County were utilized in pinpointing industries violating toxic release standards. Socio-historical data was obtained from government and historical records and reports, books, and newspaper clippings on Dallas County. Maps and data were obtained from the North Central Texas Council of Governments, and the cities of Dallas and Garland. Chapter I discusses the synergetic forces of capitalism, urban growth, uneven development, and settlement patterns resulting in the distribution of environmental contaminants. Chapter II reviews the literature and presents evidence that race and class are strong predictors of where environmental contaminants are located. Chapter III outlines the data and methods employed. Chapter IV traces the historical development of Dallas County. Chapter V details those political, economic, and social factors contributing to the convergence of people and contaminants within three selected neighborhoods. The forces which historically relegate minorities, particularly Blacks and Hispanics, and the poor to less desirable jobs, cheaper housing, and land costs are also explored. Cheap land and labor attract industry which, in turn, attracts more laborers. Chapter VI, the summary and conclusions, utilizes the socio-spatial approach in examining urban infrastructure development (i.e. roads and railways) which also reduces adjacent land costs making housing more affordable for minorities and the poor. This study concludes that because of historical development and capitalism's exploitation of labor, these populations become entrenched in neighborhoods located adjacent to those industries where contaminants are emitted.

Submitted by Rosina Valeria Lanzellotti Mattiussi Teixeira (rosina.teixeira@unisantos.br) on 2018-03-08T19:08:23Z No. of bitstreams: 1 Dennise Pimentel Claro.pdf: 637790 bytes, checksum: c4ed000204776db603ecf343f477a919 (MD5) / Made available in DSpace on 2018-03-08T19:08:23Z (GMT). No. of bitstreams: 1 Dennise Pimentel Claro.pdf: 637790 bytes, checksum: c4ed000204776db603ecf343f477a919 (MD5) Previous issue date: 2010-06-10 / Introduction - In 2001, it was reported the presence of toxic sources in areas located in the estuary of Santos and Sao Vicente, such as heavy metals, organochlorine, polychlorinated biphenyls, dioxins and furans. The exposure to these contaminants produces several adverse effects on the cardiovascular system of humans by damaging the endothelial cells of blood. To understand the impact of health conditions in these contaminated areas it is important to explore the risk of developing cardiovascular disease in the exposed population. Objective - To analyze the mortality of cardiovascular diseases in areas exposed to the referred environmental contaminants. Methods ¿ A cross-sectional study with analysis of historical series allowed an investigation of the mortality from cardiovascular disease, as provided by Fundação SEADE in five areas determined by a previous study entitled "Epidemiological Study in the Baixada Santista - Santos Estuary: Assessment of predictors of effects and exposure to environmental contaminants.", which investigated the health effects associated with exposure to environmental contaminants among residents of areas alongside Santos estuary. In this study the deaths of the five areas were subjected to descriptive analysis based on the period from 2003 through 2007 of the national census (IBGE) of 2000. The mortality rates were calculated by the direct method to standardize them with the population of São Paulo city. In addition to standardized mortality rates were estimated and the average mortality ratios. The resulting estimates allowed a comparison between the contaminated areas and the area that is contaminated free. The comparison between two proportion and Kruskal-Wallis tests was used with a significance level of 0.05. Results - observed the highest mortality coefficient in Area 1, with 24.66 per 1000 of male population, with statistically significant difference (p<0.005), but other areas with environmental contaminants their average coefficient ranged between 1.47 per 1000 to 3.96 per 1000 in both gender. Also, in both gender and all periods, there was significant statistical difference between the contaminated area 1 and Bertioga. The other areas sometimes presented lower coefficient ranged than the area without exposure to environmental contaminats (p<0.05).The mortality also showed high ratios in Area 1 (Pilões) compared to all other areas of the sample. And up to 32 times higher among females in 2003 compared with the control area (area 5, located in Bertioga). Conclusion ¿ for the analysis, higher mortality rates in Pilões and Água Fria was found, although it needs further studies to investigate a causal relationship between exposure and outcome studied. / Introdução - Em 2001 foi relatada a presença de fontes tóxicas em áreas localizadas na região estuarina de Santos e São Vicente, como os metais pesados, organoclorados, bifenilas policloradas, dioxinas e furanos. A exposição a esses contaminantes, a longo prazo, produzem diversos efeitos deletérios à saúde do ser humano, sendo uma delas o aparecimento de doenças cardiovasculares, através do dano nas células endoteliais dos vasos sanguíneos. Explorar o perfil das doenças cardiovasculares na população exposta permite entender o impacto das condições de saúde nestas áreas contaminadas. Objetivo ¿ analisar o perfil da mortalidade de doenças cardiovasculares nas áreas expostas a contaminantes ambientais. Casuística e Método ¿ estudo transversal com análise de séries históricas. Foram estudados os óbitos por doenças cardiovasculares, fornecidas pela Fundação SEADE, em 5 áreas determinadas por um estudo prévio intitulado ¿Estudo Epidemiológico na População Residente na Baixada Santista ¿ Estuário de Santos: Avaliação dos Indicadores de Efeito e de Exposição à Contaminantes Ambientais.¿, financiado pelo CNPq, no qual investigou os efeitos à saúde associados à exposição aos contaminantes ambientais entre moradores da baixada Santista. No presente trabalho os óbitos das 5 áreas foram submetidos a uma análise descritiva, no período de 2003 a 2007, utilizando as estimativas populacionais do Instituto Brasileiro de Geografia e Estatística no ano 2000. Os cálculos dos coeficientes de mortalidade foram realizados pelo método direto, padronizando-os com a população do município de São Paulo. Além do coeficiente padronizado foram calculados os coeficientes médios e as razões entre os coeficientes de mortalidade por doenças cardiovasculares. Os resultados calculados permitiram uma comparação entre as áreas contaminadas e a área não contaminada, o município respectivo do local, e o município de São Paulo. Foi utilizado o teste de comparação entre duas proporções e o teste Kruskal-Wallis com teste Dunn positivo, adotando um nível de significância menor ou igual a 0,05. Resultados ¿ o coeficiente de mortalidade padronizados por doenças cardiovasculares mais elevado foi de 24,66/1000 habitantes na Área 1 (Pilões e Água Fria) no sexo masculino, com diferença estatisticamente significante com a área não contaminada (p<0,05), Nas outras áreas contaminadas os coeficientes médio de mortalidade variaram entre 1,47/1000 a 3,96/1000 em ambos os sexos, valores inferiores a area 1. Em todos os períodos, observou-se diferença estatisticamente significante entre a área 1 (Pilões) e a área contaminada (Bertioga), em ambos os sexos. Nas áreas 2 (Cubatão Centro), área 3 (São Vicente) e área 4 (Vicente de Carvalho) em alguns períodos da série histórica apresentaram coeficientes de mortalidade inferiores a área contaminada, sendo estatisticamente significante. As razões de mortalidade também se apresentaram elevadas na área 1 (Pilões) com todos os locais de comparação, chegando a 32 vezes maior no sexo feminino no ano de 2003, quando comparado com a área controle (área 5, localizada na região de Bertioga). Conclusão ¿ a análise da mortalidade, através dos coeficientes, revelou-se alta na área contaminada a poluentes ambientais, localizada em Pilões e Água Fria, porém há necessidade de novos estudos para investigar uma relação causal entre a exposição e o desfecho estudado.

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

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

L’Homme est exposé tout au long de sa vie à de nombreux contaminants présents dans l’environnement et l’alimentation généralement à faibles doses et en mélanges. L’évaluation des risques pose problème dans la mesure où il est bien établi qu’il existe des différences de réponse entre l’homme et l’animal. Quelle que soit la voie d’exposition, de par son rôle majeur dans la biotransformation des xénobiotiques, le foie est considéré comme un organe cible pour de nombreuses classes de produits chimiques potentiellement cytotoxiques, génotoxiques voire cancérogènes. Nous avons utilisé la lignée de cellules hépatiques humaines HepaRG non transformées pour évaluer la toxicité chronique et/ou le pouvoir cancérogène de pesticides et de composés génotoxiques présents dans l’environnement. Cette lignée est la seule connue pour avoir conservé des propriétés proches des hépatocytes humains en culture primaire. Dans une première partie nous avons confirmé le maintien de ses capacités fonctionnelles à confluence par l’analyse du transcriptome et de la biocinétique de 4 médicaments, après traitements quotidiens pendant 14 jours. Nous avons ensuite recherché les effets de mélanges de pesticides après des expositions aiguës et répétées. Nous avons ainsi montré que : 1. l’isomalathion, une impureté majeure du malathion, joue un rôle prépondérant sur la toxicité hépatique de ce dernier et qu’il inhibe la carboxylesterase impliquée dans le métabolisme des deux composés; 2. l’endosulfan et le méthoxychlore, deux organochlorés métabolisés par les CYP3A4 et 2B6, agissent de manière synergique sur leur cytotoxicité après une exposition unique ou répétée. De plus, alors que l'activité du CYP3A4 est inhibée de manière réversible par l’endosulfan, le méthoxychlore l’augmente. En revanche, l’activité du CYP2B6 est induite par les deux pesticides. Lorsqu’ils sont en mélange équimolaire un effet additif ou antagoniste est observé sur l'activité du CYP3A4 et du CYP2B6 respectivement quelle que soit la durée de l’exposition. Enfin, dans une troisième partie, nous avons exposé des cellules HepaRG pendant une quinzaine de passages à de faibles doses de deux contaminants génotoxiques nécessitant une bioactivation, l’aflatoxine B1 et une amine aromatique hétérocyclique, le PhiP, et démontré l’acquisition de propriétés de cellules transformées (par exemple croissance sur agar, migration dans le test de griffure et surexpression de gènes associés au cancer). Au total, nos résultats démontrent tout l’intérêt que représente la lignée hépatique humaine HepaRG métaboliquement compétentes pour l’étude de la toxicité chronique et/ou le potentiel cancérogène des contaminants de l’environnement. Ils ont permis de mettre en évidence d’interactions entre des pesticides en mélanges binaires et pour la première fois d’analyser le potentiel cancérogène de contaminants génotoxiques dans une lignée hépatique humaine. / Humans are exposed throughout their life to many environmental and food contaminants, usually at low doses and in mixtures. Risk assessment remains questionable as it is well established that there are differences in the response to chemicals between humans and animals. Regardless of the route of exposure, due to its major role in xenobiotic biotransformation, the liver is considered as a target organ for many classes of chemicals potentially cytotoxic, genotoxic or carcinogenic. We used the HepaRG cell line to evaluate chronic toxicity and/or carcinogenicity of pesticides and genotoxic compounds. This cell line is the only one known to exhibit properties similar to those of human hepatocytes in primary culture. In the first part we confirmed the maintenance of functional capacities of these cells at confluence by transcriptomic and biokinetic analysis of several drugs after a 14-day treatment. We then investigated the effects of mixtures of pesticides after acute and repeated exposures. We showed that : 1. Isomalathion, a major impurity of malathion, played a leading role on liver toxicity and inhibited carboxylesterase that is involved in the metabolism of these two compounds; 2. Endosulfan and methoxychlor, two organochlorines, metabolized by CYP3A4 and CYP2B6, acted synergistically on their cytotoxicity after single or repeated exposure. Moreover, whereas activity of CYP3A4 was reversibly inhibited by endosulfan and increased by methoxychlor. By contrast, CYP2B6 activity was induced by these two pesticides while in equimolar mixtures, they caused additive or antagonistic effects on CYP3A4 and CYP2B6 activities respectively, regardless of the duration of exposure. Finally, in the third part, we exposed HepaRG cells for up to 15 passages to low doses of two genotoxic contaminants which required bioactivation, aflatoxin B1 and heterocyclic aromatic amine, PhIP, and demonstrated the appearance of properties of transformed cells (e.g. growth on agar, cell migration in the wound healing test and overexpression of a number of genes associated with cancer). Altogether, our results demonstrate the great potential interest that represents the metabolically competent human liver cell line HepaRG for the study of chronic toxicity and/or carcinogenic potential of environmental contaminants. They highlight possible interactions between pesticides in binary mixtures and for the first time, demonstrate that the carcinogenic potential of genotoxic contaminants can be analyzed in an human hepatic cell line.

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

There are a great variety of environmentals contaminants, a lot of which are understudied asit is today. The aim of this study was to develop an in-house high-resolution spectral librarycontaining environmental contaminants, with focus on plastic additives. The spectral librarywould then be used to perform suspect screening on real sample extracts. A list of standardswas acquired, prepared and then analyzed with GC-EI-Orbitrap. The files from the analysiswere converted and then processed in a software called MS-DIAL. Once the analyte wasidentified, the data was exported to MS-FINDER. MS-FINDER performs fragmentannotation and generates in silico spectra, and the spectral data is then saved as an MSP file.An MSP file is a file based on text containing mass spectrometric data, and is the mostcommonly supported file for spectral libraries. The individual MSP files for the standards arethen collected into a common MSP file, which can be opened in MS-DIAL to performsuspect screening. The suspect screening in this study was performed as a retrospectiveanalysis of indoor dust samples from a study in 2021.From the beginning, 60 standards out of 80 available standards were included. The principalreason for a standard not being included was that the compound would most certainly notelute using GC with the set analytical parameters. Out of the 60 analyzed standards, 32compounds could be added to the spectral library. No distinct peak within thechromatographic run time was the main reason for not being able to add a standard. Despiteadding 32 different compounds into the spectral library, a total of 51 individual MSP-fileswere generated. Some of the technical mixtures generated a chromatogram with severaldifferent peaks, and MSP files were generated for each of the most prominent peaks. Thiswas done since it could still provide useful information in an identification process.The suspect screening in this study was performed as a retrospective analysis of indoor dustsamples from 2019. Into the spectral library, 32 different compounds were included, and 10of these were found in the different indoor dust samples when performing the suspectscreening.Building a spectral library in this way is a time consuming process with a lot of manual work,but spectral libraries are nonetheless necessary in the process of effectively monitoringenvironmental contaminants, to assist in risk assessment and decision making for regulatorson identified contaminants.