This chart shows the main types of organochlorines found in marine mammals and fish. The levels in fish are much lower than in marine mammal blubber. Fish that feed on invertebrates or fish that are low in fat, such as whitefish and northern pike, have non-detectable or very low levels of these contaminants.
Of these contaminants, toxaphene and chlordane are considered to be of the most concern for human health - but this is in part because so little is known about their effects on humans. Because of this uncertainty and because of the nutritional and cultural importance of fish and marine mammals in Aboriginal diets, health professionals and community representatives conclude that the benefits of eating these foods outweigh the risks associated with contaminants.
Canada is spearheading international efforts to control the production and use of persistent organic pollutants. Most of these substances are no longer used in Canada and many other countries, but some remain important industrial chemicals and pesticides in developing nations.
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