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The objectives of this paper are to: assess the impact of exposure to current levels of environmental contaminants in the Canadian Arctic on human health; identify the data and knowledge gaps that need to be filled by future human health research and monitoring; examine how these issues have changed since our first assessment [Van Oostdam, J., Gilman, A., Dewailly, E., Usher, P., Wheatley, B., Kuhnlein, H. et al., 1999. Human health implications of environmental contaminants in Arctic Canada: a review. Sci Total Environ 230, 1-82]. The primary exposure pathway for contaminants for various organochlorines (OCs) and toxic metals is through the traditional northern diet. Exposures tend to be higher in the eastern than the western Canadian Arctic. In recent dietary surveys among five Inuit regions, mean intakes by 20- to 40-year-old adults in Baffin, Kivalliq and Inuvialuit communities exceeded the provisional tolerable daily intakes (pTDIs) for the OCs, chlordane and toxaphene. The most recent findings in NWT and Nunavut indicate that almost half of the blood samples from Inuit mothers exceeded the level of concern value of 5 microg/L for PCBs, but none exceeded the action level of 100 microg/L. For Dene/Métis and Caucasians of the Northwest Territories exposure to OCs are mostly below this level of concern. Based on the exceedances of the pTDI and of various blood guidelines, mercury and to a lesser extent lead (from the use of lead shot in hunting game) are also concerns among Arctic peoples. The developing foetus is likely to be more sensitive to the effects of OCs and metals than adults, and is the age groups of greatest risk in the Arctic. Studies of infant development in Nunavik have linked deficits in immune function, an increase in childhood respiratory infections and birth weight to prenatal exposure to OCs. Balancing the risks and benefits of a diet of country foods is very difficult. The nutritional benefits of country food and its contribution to the total diet are substantial. Country food contributes significantly more protein, iron and zinc to the diets of consumers than southern/market foods. The increase in obesity, diabetes and cardiovascular disease has been linked to a shift away from a country food diet and a less active lifestyle. These foods are an integral component of good health among Aboriginal peoples. The social, cultural, spiritual, nutritional and economic benefits of these foods must be considered in concert with the risks of exposure to environmental contaminants through their exposure. Consequently, the contamination of country food raises problems which go far beyond the usual confines of public health and cannot be resolved simply by risk-based health advisories or food substitutions alone. All decisions should involve the community and consider many aspects of socio-cultural stability to arrive at a decision that will be the most protective and least detrimental to the communities.

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Pooling of surplus serum from individual samples, collected between 2007 and 2009 during Cycle 1 of the Canadian Health Measures Survey (CHMS), was performed to develop a national baseline estimate of brominated flame retardants in Canadians. Serum samples were categorized by sex and distributed by five age groups ranging from 6 to 79years. Nearly 5000 (4583) serum samples were used to form 59 composite pools. Serum pools were created to ensure a high detection frequency of these analytes in serum because low volume samples had previously resulted in non-detectable concentrations. The analytes of interest in these serum pools included 23 polybrominated diphenyl ethers (PBDEs) and three hexabromocyclododecane (HBCD) isomers (α-, β- and γ-HBCD). PBDEs were observed in all samples tested and total PBDE concentrations ranged from 27ngg(-1) lipid to 130ngg(-1) lipid (geometric mean [GM] 46ngg(-1) lipid). ∑PBDE concentrations were significantly elevated in samples representing the 6-11year old age group (GM 65ngg(-1) lipid) relative to ages above 40years, although no difference in concentration was observed between the sexes. PBDE concentrations in Canadian sera from the general population were higher than reported in Europe and Asia, but a little lower than observed in the US. PBDE 47 was the greatest contributor to ∑PBDE concentrations and the GM concentration for this congener was 22ngg(-1) lipid. The other dominant contributors to ∑PBDE concentrations were in descending order: 153 [GM 9.4ngg(-1) lipid]>99 [GM 4.6ngg(-1) lipid]≅100 [GM 4.1ngg(-1) lipid]>209 [GM 1.1ngg(-1) lipid] and 183 [GM 0.42ngg(-1) lipid]. ∑HBCD was detected in all samples analysed, although most samples were observed at concentrations <1ngg(-1) lipid, similar to global concentrations. α-HBCD was the dominant contributor to ∑HBCD concentrations in Canadians although β- and γ-HBCD were detected in 23% and 35% of the samples, respectively. No differences in ∑HBCD concentration were associated with age or sex. This dataset represents the first national data describing HBCD isomers and some PBDEs (e.g., 183, 209) in Canadians.

Four white sturgeon were collected from the upper Fraser River near Prince George, British Columbia, Canada, in the fall of 1991 and 1992. Two additional fish were taken from the Fraser River near Williams Lake, some 250 km downstream of Prince George. Samples of white muscle, red muscle, liver, and roe were analyzed for metals, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho and mono-ortho polychlorinated biphenyls (PCBs), and chlorophenols to determine whether the tissues of this species were acceptable for human consumption. The concentrations of mercury in the white muscle and liver of several fish from the upper Fraser River exceeded the provincial tissue residue criteria for people who consumed low quantities of fish (i.e., 210 g wet weight/week). The concentrations of PCDDs, PCDFs, and coplanar PCBs (expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents) in red muscle and liver of these fish exceeded the Health Canada working guidelines for the protection of human health. By comparison, white sturgeon collected in the lower Fraser River had much lower concentrations of metals and organic contaminants. The differences in contaminant burdens in fish from the two widely separated reaches of the river reflect their proximity to or distance from known contaminant sources.