Seeking the Source: Dioxin Exposure Levels and Determinants and Fluoroalkyl Substance Determinants in Arctic and Subarctic Communities within Canada

• Main Author: Simpson, Ashlyn
• Format: Master Thesis
• Language: English
• Published: University of Waterloo 2023
• Subjects: exposure; contaminant; persistent organic pollutant; Arctic; Indigenous; Traditional Food; biomonitoring; dioxin; furan; dioxin-like PCB; PFAS; Northwest Territories; Old Crow; Subarctic; Yukon
• Online Access: http://hdl.handle.net/10012/20116

Abstract Background Dioxins, furans, and non-ortho dioxin-like polychlorinated biphenyls (PCBs), and per- and poly- fluoroalkyls (PFAS) are persistent toxic chemicals that have been detected in areas far from known emission sources. Following biomonitoring projects conducted in the Dehcho Region, Northwest Territories (2016-2018) and Old Crow, Yukon Territory (2019), elevated levels of PFNA were detected, and dioxins, and like-congeners were yet to be investigated. This thesis reports on dioxin exposure levels and identifies determinants that may influence dioxin and PFAS exposures in the study areas. Research Questions To assess dioxin, furan, and non-ortho dioxin-like PCB exposures, two research questions are raised: What are the levels of dioxins in blood plasma samples from Old Crow and how do these compare to the general population of Canada? and are there specific demographic variables that are associated with higher or lower exposure? The determinants of exposure are then explored among the participating communities with dioxin and PFAS exposure measures: Are there lifestyle factors or traditional foods consumption patterns that are associated with biomarkers of these analytes? Methods Biobanked plasma samples (n=54) from Old Crow were analyzed for dioxins, furans, and non-ortho dioxin-like PCBs. Data from surveys on traditional food consumption and lifestyle factors were collected in Old Crow and the Dehcho Region. Descriptive statistics were used to quantify differences in exposure between the Old Crow and Canadian Health Measures Survey (CHMS) data, then simple linear regression and multiple variable regression was used to identify the traditional foods and lifestyle factors that may influence PFAS, and dioxin and dioxin-like congener exposures. Results Most dioxins, furans, and non-ortho dioxin-like PCB exposures were lower, or similar in the study areas in comparison to the respective levels in the general population of Canada. Like the previous findings with PFNA, PCB 169 levels appeared to be ...