SPATIAL VARIABILITY OF CHLORINATED BORNANES (TOXAPHENE) IN FISHES FROM YUKON LAKES

The spatial variability of chlorinated bornane (SIGMACHB, toxaphene) concentrations was studied in fishes from several lakes in the Yukon Territory. Burbot (Lota lota), lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) were collected from twelve lakes on the Yukon River system and from one lake on the Liard River system between September 1990 and April 1992. Individual and composite tissue samples were analysed for chlorinated bornanes (SIGMACHB, toxaphene) using capillary gas chromatography. Inter-lake SIGMACHB concentrations ranged from 54 to 2805 ng/g wet weight in burbot liver, from < 10 to 657 ng/g in lake trout muscle, and from < 10 to 40 ng/g in lake whitefish muscle. SIGMACHB in burbot and lake trout varied significantly among lakes, with the highest concentrations in fishes from Lake Laberge. Archived lake whitefish samples from Lake Laberge (1974) contained lower concentrations of SIGMACHB than those found in fish collected between 1990 and 1992. Interlake variability in SIGMACHB may be partially related to differences in the food chains of the lakes.