Human Biomonitoring of and Determinants of Biomarker Levels for Contaminants and Nutrients in Old Crow, Yukon Territory

Traditional food is an important part of the diet for many Arctic residents, particularly First Nations, and is associated with some improved health outcomes, nutrition, and food security. However, these foods can also pose potential risks via exposure to certain contaminants, including those which are found at higher levels in the Arctic. Several large-scale human biomonitoring projects have been conducted in Canada, however, prior to the one herein, none have recruited participants living in the Yukon. This thesis used the results of a human biomonitoring clinic conducted in Old Crow, Yukon, in 2019 to respond to community questions and concerns regarding human exposure levels of contaminants and nutrients in the community, and how these levels relate to traditional food consumption and other lifestyle and demographic determinants. The clinic included the collection of hair, blood, and urine samples for the analysis of contaminants and nutrients, and the administration of dietary and health messaging surveys. This thesis compared results of the clinic those from reference populations and health-based guidance values. Levels of most measured contaminants and nutrients, including most metals (e.g. mercury, cadmium), and persistent organic pollutants (POPs) (e.g. polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT)) were similar in Old Crow to those in the general Canadian population and were below available health-based guidance values. Some contaminants and nutrients, including the metal nutrients manganese and cobalt, the toxic metal lead, and the pesticide hexachlorobenzene (HCB), were elevated in Old Crow relative to the general Canadian population. These contaminants and nutrients were analyzed further to identify potential local determinants of urine and blood levels. Generalized linear models were run to identify significant associations between blood and urine levels of these substances, with factors including demographics, lifestyle risk factors, and traditional food consumption. Old Crow participants had higher levels of some key contaminants and nutrients if they reported eating some traditional foods, including moose bones in soup or stew (86% higher urinary average manganese levels), caribou kidneys (22% higher average blood manganese levels and 58% higher average blood lead levels), and whitefish (28% higher average blood cobalt levels). Associations between moose and caribou organ consumption and levels of lead and HCB were also observed in reference populations in the Dehcho and Sahtú regions of the Northwest Territories, and a pooled population including those regions and Old Crow. However, no individual determinants were associated with HCB plasma levels Old Crow. In an effort to estimate dietary exposure to HCB in the community of Old Crow, a stochastic model was constructed based on dietary surveys and traditional food sampling conducted in the region. This model also estimated intake of healthy omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from the same foods. Modeling showed that the majority (>60%) of estimated dietary HCB intake in Old Crow was from lipid-rich caribou organs, such as fat, bone marrow, ribs, and kidney. Estimated dietary intake of HCB was below relevant health-based guidance values for all participants. Traditional foods, particularly fish, were also identified as a significant source of healthy omega-3 fatty acids. The results of this thesis support the conclusion that the benefits of traditional food consumption generally outweigh the risks of contaminant exposure for this population

Evaluating the respiratory bioaccessibility of nickel in soil through the use of a simulated lung fluid

Simulated lung fluids are solutions designed to mimic the composition of human interstitial lung fluid as closely as possible. Analysis of mineral dusts using such solutions has been used to evaluate the respiratory bioaccessibility of various elements for which solubility in the lungs is a primary determinant of reactivity. The objective of this study was to employ simulated lung fluid analysis to investigate the respiratory bioaccessibility of nickel in soils. Current occupational guidelines in Australia regulate nickel compounds in terms of water solubility, though this may not be an accurate estimation of the total nickel that will dissociate in the lungs. Surface soils were collected from the city of Kalgoorlie in Western Australia, the site of an operational nickel smelter and metal mining activities. The fraction of the samples less than 10 μm was extracted from the soil, and it was this sub-10-μm fraction that was found to hold most of the total nickel present in the soil. The fine fraction was analyzed using a simulated lung fluid (modified Gamble’s solution) to isolate the nickel phases soluble in the lungs. In addition, a sequential extraction was employed to compare the bioaccessible fraction to those dissolved from different binding forms in the soil. In all samples, the simulated lung fluid extracted more nickel than the two weakest leaches of the sequential extraction combined, providing a more representative nickel bioaccessibility value than the current water leach method

Traditional Food Consumption and Other Determinants of Exposure for Lead, Cobalt, Manganese, and Hexachlorobenzene in Northern Canada

Results of a 2019 human biomonitoring study indicated that several parameters, including lead, cobalt, manganese, and hexachlorobenzene, were elevated in blood and urine samples in Old Crow, Yukon, in comparison to the general Canadian population. This study aims to identify possible local determinants of levels of these parameters, including consumption of locally harvested traditional foods, lifestyle factors, and demographics, in Old Crow and, for comparison, two other northern populations: communities in the Dehcho and Sahtú regions of the Northwest Territories. We ran generalized linear models to identify possible associations between individual determinants of exposure and key biomarkers, controlling for age and sex. In Old Crow, several variables were associated with elevated exposure levels of these biomarkers, including drinking untreated river water (29% higher blood manganese levels and 120% higher blood lead levels), eating caribou kidneys (22% higher blood manganese levels and 58% higher blood lead levels), and eating whitefish (28% higher blood cobalt levels). Additionally, in order to differentiate results in Old Crow from those in other northern regions and to identify trends across regions, we observed relationships between consumption of moose and caribou organs and lead and hexachlorobenzene levels in the reference populations and pooled population groups. Though levels of particular contaminants may be elevated in some traditional foods, these foods remain an important source of nutrients for members in these communities and provide other benefits, including increased physical activity through harvesting, mental health improvements, and spiritual wellness.Selon les résultats d’une étude de biosurveillance humaine réalisée en 2019, le taux de plusieurs paramètres, dont le plomb, le cobalt, le manganèse et l’hexachlorobenzène se trouvant dans des échantillons de sang et d’urine de résidents d’Old Crow, au Yukon étaient élevés par rapport à la population canadienne en général. La présente étude vise à identifier les déterminants locaux possibles attribuables aux niveaux de ces paramètres, y compris la consommation d’aliments traditionnels locaux, des facteurs liés au mode de vie et les données démographiques. Les données d’Old Crow sont comparées aux données provenant de deux autres populations nordiques, soit celles des régions du Dehcho et du Sahtú dans les Territoires du Nord-Ouest. Des modèles linéaires généralisés ont été réalisés afin de déterminer les corrélations possibles entre les déterminants individuels et les biomarqueurs clés, en tenant compte des variables de l’âge et du sexe. À Old Crow, plusieurs variables ont été associées aux taux élevés de ces biomarqueurs, notamment la consommation d’eau de rivière non traitée (taux de manganèse dans le sang plus élevé dans une mesure de 29 % et taux de plomb plus élevé de 120 %), la consommation de rognons de caribou (taux de manganèse dans le sang plus élevé dans une mesure de 22 % et taux de plomb plus élevé de 58 %) et la consommation de poissons blancs ou corégones (taux de cobalt dans le sang plus élevé dans une mesure de 28 %). De plus, afin de différencier les résultats d’Old Crow de ceux des autres régions nordiques et de cerner les tendances dans ces régions, nous avons observé des liens entre la consommation d’organes d’orignal et de caribou et les taux de plomb et d’hexachlorobenzène dans les bassins de population de référence des Territoires du Nord-Ouest. Bien que les taux de contaminants puissent être élevés dans certains aliments traditionnels, ces aliments demeurent une source importante de nutriments pour les membres de ces communautés et offrent d’autres avantages, notamment une plus grande activité physique grâce à la récolte, des améliorations sur le plan de la santé mentale et une source de bien-être spirituel

Sources of exposure to lead in Arctic and subarctic regions: a scoping review

ABSTRACTUnderstanding lead exposure pathways is a priority because of its ubiquitous presence in the environment as well as the potential health risks. We aimed to identify potential lead sources and pathways of lead exposure, including long-range transport, and the magnitude of exposure in Arctic and subarctic communities. A scoping review strategy and screening approach was used to search literature from January 2000 to December 2020. A total of 228 academic and grey literature references were synthesised. The majority of these studies (54%) were from Canada. Indigenous people in Arctic and subarctic communities in Canada had higher levels of lead than the rest of Canada. The majority of studies in all Arctic countries reported at least some individuals above the level of concern. Lead levels were influenced by a number of factors including using lead ammunition to harvest traditional food and living in close proximity to mines. Lead levels in water, soil, and sediment were generally low. Literature showed the possibility of long-range transport via migratory birds. Household lead sources included lead-based paint, dust, or tap water. This literature review will help to inform management strategies for communities, researchers, and governments, with the aim of decreasing lead exposure in northern regions

Use of the WHO Access, Watch, and Reserve classification to define patterns of hospital antibiotic use (AWaRe) : an analysis of paediatric survey data from 56 countries

Background Improving the quality of hospital antibiotic use is a major goal of WHO's global action plan to combat antimicrobial resistance. The WHO Essential Medicines List Access, Watch, and Reserve (AWaRe) classification could facilitate simple stewardship interventions that are widely applicable globally. We aimed to present data on patterns of paediatric AWaRe antibiotic use that could be used for local and national stewardship interventions. Methods 1-day point prevalence survey antibiotic prescription data were combined from two independent global networks: the Global Antimicrobial Resistance, Prescribing, and Efficacy in Neonates and Children and the Global Point Prevalence Survey on Antimicrobial Consumption and Resistance networks. We included hospital inpatients aged younger than 19 years receiving at least one antibiotic on the day of the survey. The WHO AWaRe classification was used to describe overall antibiotic use as assessed by the variation between use of Access, Watch, and Reserve antibiotics, for neonates and children and for the commonest clinical indications. Findings Of the 23 572 patients included from 56 countries, 18305 were children (77.7%) and 5267 were neonates (22.3%). Access antibiotic use in children ranged from 7.8% (China) to 61.2% (Slovenia) of all antibiotic prescriptions. The use of Watch antibiotics in children was highest in Iran (77.3%) and lowest in Finland (23.0%). In neonates, Access antibiotic use was highest in Singapore (100.0%) and lowest in China (24.2%). Reserve antibiotic use was low in all countries. Major differences in clinical syndrome-specific patterns of AWaRe antibiotic use in lower respiratory tract infection and neonatal sepsis were observed between WHO regions and countries. Interpretation There is substantial global variation in the proportion of AWaRe antibiotics used in hospitalised neonates and children. The AWaRe classification could potentially be used as a simple traffic light metric of appropriate antibiotic use. Future efforts should focus on developing and evaluating paediatric antibiotic stewardship programmes on the basis of the AWaRe index. Copyright (C) 2019 The Author(s). Published by Elsevier Ltd