Hexachlorobenzene and omega-3 fatty acid intake from traditional foods in the northern Yukon: A risk and benefit analysis.

A human biomonitoring study was conducted in the community of Old Crow, Yukon, in 2019, finding that levels of hexachlorobenzene (HCB) in plasma were elevated in the community relative to the general Canadian population. The aim of this study was to estimate dietary intake of both hexachlorobenzene, and the nutrient omega-3 fatty acids from locally harvested traditional foods in Old Crow, with the aim of identifying possible regional sources of exposure. A stochastic model was constructed to estimate intake of both hexachlorobenzene and the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Average predicted hexachlorobenzene exposure levels from traditional food consumption in Old Crow were below the tolerable daily intake of 1600-1700 ng/kg body weight/day in both average (18 ng/kg body weight/day) and short-term maximum (27 ng/kg body weight/day) exposure models. The primary contributors to average hexachlorobenzene intake were caribou fat, bone marrow, ribs, and kidneys, and Chinook salmon muscle. Average estimated dietary EPA + DHA intake levels from traditional foods were below the recommendation of 2.1 to 3.2 g of EPA + DHA per week in the average (1.6 g/week) exposure model, but above this recommendation in the short-term maximum model (3.3 g/week). The primary contributors to average EPA + DHA intake were the meat of Chinook, coho, and, chum salmon muscle, and whitefish muscle and eggs. The results of this study support the message that traditional foods continue to be an important source of nutrients and other health benefits and that the health benefits of traditional foods generally outweigh contaminant risks.

Human biomonitoring of dioxins, furans, and non-ortho dioxin-like polychlorinated biphenyls (PCBs) in blood plasma from Old Crow, Yukon, Canada (2019).

Dioxins, furans, and dioxin-like polychlorinated biphenyls (PCBs) are a group of persistent and toxic chemicals that are known to have human health effects at low levels. These chemicals have been produced for commercial use (PCBs) or unintentionally as by-products of industry or natural processes (PCBs, dioxins, and furans). Additionally, dioxin-like PCBs were formerly used in electrical applications before being banned internationally (2004). These chemicals are widely dispersed in the environment as they can contaminate air and travel hundreds to thousands of kilometers before depositing on land or water, thereafter, potentially entering food chains. Community concerns surrounding the safety of traditional foods prompted a human biomonitoring project in Old Crow, Yukon Territory (YT), Canada (2019). Through collaborative community engagement, dioxins and like compounds were identified as a priority for exposure assessment from biobanked samples. In 2022, biobanked plasma samples (n = 54) collected in Old Crow were used to measure exposures to seven dioxins, ten furans, and four dioxin-like PCBs. 1,2,3,6,7,8-HxCDD, 1,2,3,7,8,9-HxCDD, 1,2,3,4,6,7,8-HpCDD, OCDD, 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF, PCB 126, and PCB 169 were detected in at least 50 % of samples. Among these analytes, the only congener at elevated levels was PCB 169, which was approximately ∼2-fold higher than the general population of Canada. No significant sex-based or body mass index (BMI) differences in biomarker concentrations were observed. Generally, the concentrations of the detected congeners increased with age, except for 1,2,3,4,6,7,8-HpCDD. For the first time, this research measures dioxin and like-compound exposures in Old Crow, advancing the information available on chemical exposures in the Arctic. Further research could be directed towards the investigation of PCB 169 exposure sources and temporal monitoring of exposures and determinants.