Exposure to Contaminants Through Wildlife

Recent research on contaminants in Arctic wildlife foods has been conducted in several Arctic countries through the Arctic Monitoring and Assessment Program (AMAP) and the Canadian Arctic Environmental Strategy/Northern Contaminants Program. Research on exposure to contaminants to residents of Arctic communities through food consumed was carried out using the interview strategies noted above combined with laboratory analyses of food contaminants, particularly heavy metals and organochlorines. The encyclopedia entry on Bioconcentration describes general findings about the contents of these contaminants in wildlife. In this section, we will describe the exposure through diet to Arctic residents, particularly indigenous peoples.

The contaminants present in wildlife foods are different from those in agricultural and processed/purchased foods. The wildlife contaminants are present as a result of long-range transport or point source emissions, and are accumulated through the food chain. Fat foods are generally sources of organochlorines, and muscle and skin tissues are sources of heavy metals. Organ food items (liver, kidney, brain, etc.) are sources of both heavy metals and organochlorine contaminants. Each contaminant has a tolerance level for daily intake from food, which results from estimating the amount of contaminant in a food item and the quantity of food consumed. Further, consideration is given to the repeatability and seasonality of intake, with a greater risk when a particular food is consumed regularly on a year-round basis.

The contaminants of greatest concern at this point of time are thought to be the heavy metal mercury, and the organochlorines chlordane and toxaphene. These three contaminants are found in a variety of sea mammals, fish, and the organs of land animals; they are rarely found in plants. On an average basis, Inuit communities consume more of these contaminants than do indigenous peoples who harvest a majority of their foods from land-based sources, and who consume less fat derived from wildlife. Dietary exposure estimates across the circumpolar Arctic have shown a wide variance in mercury intakes. The highest levels of mercury in maternal blood were found among those who eat large amounts of marine food, especially in Greenland and East Canada. The daily intake of mercury by some Inuit in Greenland and eastern Canada may be more than five times the limit set by the World Health Organization (WHO). At present, there are no studies documenting a positive correlation between this high intake and negative health effects, for example, neurological effects. The high levels of selenium also found in sea mammals and Inuit from Greenland and eastern Canada may counteract the potential negative effect of mercury.

It is important to recognize that the benefits of traditional food use (cultural and nutritional) must be weighed against the risk of contaminant exposure. At this time, no adverse effects from contaminant intakes derived from wildlife food have been documented. However, every effort must be made to reduce the emission of persistent heavy metals and organochlo-rine contaminants into the global environment.

Laurie H.M. Chan and Harriet V. Kuhnlein

See also Bioconcentration; Contaminants; Hunting, Subsistence; Nutrition and Food; Plant Gathering

Further Reading

Blanchet, C., E. Dewailly, P. Ayotte, S. Bruneau, O. Receveur & B. Holub, "Contribution of selected traditional and market food to Nunavik Inuit women's diets." Canadian Journal of Dietetic Practice and Research, 61(2) (2000): 50-58 Bjerregaard, P., H.S. Pedersen & G. Mulvad, "The associations of a marine diet with plasma lipids, blood glucose, blood pressure and obesity among the Inuit in Greenland." European Journal of Clinical Nutrition, 54 (2000): 732-737 Kuhnlein, H.V., "Benefits and risks of traditional food for indigenous peoples: focus on dietary intakes of Arctic men." Canadian Journal of Physiological Pharmacology, 73 (1995): 765-771 Kuhnlein, H.V. & H.M. Chan, "Environment and contaminants in traditional food systems of northern indigenous peoples." Annual Review of Nutrition, 20 (2000): 595-626 Kuhnlein, H.V. & O. Receveur, "Dietary change and traditional food systems of indigenous peoples". Annual Review of Nutrition, 16 (1996): 417-442 Kuhnlein, H.V., O. Receveur & H.M. Chan, "Traditional food systems research with Canadian indigenous peoples." International Journal of Circumpolar Health, 60 (2001): 112-122 Nobmann, E.D. & A.P. Lanier, "Dietary intake among Alaska native women resident of Anchorage, Alaska." International Journal of Circumpolar Health, 60 (2001): 123-137

Nobmann, E.D., T. Byers, A.P. Lanier, J.H. Hankin & M.Y. Jackson, "The diet of Alaska Native adults: 1987—1988." American Journal of Clinical Nutrition, 55 (1992): 1024—1032 Receveur, O., M. Boulay & H.V. Kuhnlein, "Decreasing traditional food use affects diet quality for adult Dene/Metis in 16 communities of the Canadian Northwest Territories." Journal of Nutrition, 127 (1997): 2178—2186 VanOostdam, J., A. Gilman, E. Dewailly, P. Usher, B. Wheatley, H.V. Kuhnlein, S. Neve & J. Walker, "Human health implications of environmental contaminants in Arctic Canada: a review." Science of the Total Environment, 230 (1999): 1—82

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