Contaminants in Ecosystems

• Organochlorines such as toxaphene, DDT and PCBs have been found at low levels in Yukon air and snow. The main source is long-range atmospheric transport from other parts of the world. Organochlorines are found in fish throughout the Yukon although in most fish levels are low and fish are safe to eat. However, because organochlorines build up in fat and in predator species, levels can become high in some fish species in a few lakes. Consumption advisories based on toxaphene (a pesticide no longer used in Canada) have been issued for burbot livers and lake trout flesh from Lake Laberge and for burbot livers from Atlin Lake.

• Organochlorines are absent or occur only at very low levels in ducks, grouse, caribou, moose and other game animals.

• Metals are generally within natural ranges and meet consumption guidelines for berries, other food and medicinal plants, fish and wildlife. Mercury is sometimes elevated in large fish, and cadmium is high in the kidneys and livers of caribou, moose and porcupine. The source of both of these metals is natural rock. Cadmium in all wild meat is very low.