Proceedings - Teaching and Learning Centre - Simon Fraser ...

Fraser River Action Plan 3rd Research Workshop
Survey of Toxaphene in Burbot from Four Fraser Basin Lakes
C. Gray
Environment Canada
This survey was initiated after elevated levels of toxaphene were reported in fish sampled from selected lakes in
the southern Yukon and the Banff/Jasper region. Because the source of toxaphene, in most cases, was long-range
atmospheric transport, it seemed logical that similar levels of toxaphene would be found in fish from the Fraser
basin. As the Yukon-based study found highest levels in burbot liver tissue, this species was chosen for the
survey. In spring of 1995, five adult burbot were collected from Moose, Stuart, Kamloops and Nicola lakes.
These fish were shipped frozen to the lab for determination of sex, age and the presence of tumors before
removing the liver for analyses of PCBs, organochlorine pesticides and toxaphene. Only a preliminary
evaluation of the toxaphene data will be available for this workshop.
Toxaphene analyses were reported in three ways:
1. total toxaphene;
2. total Hexa-, Hepta-, Octa-, Nona-, & Deca- chlorinated homologues; and,
3. individual “Parlar” Chorobornanes.
Average total toxaphene in male burbot varied by an order of magnitude:
• 16 ng/g in Nicola;
• 123 ng/g in Stuart;
• 139 ng/g in Kamloops; and,
• 610 ng/g in Moose.
The most commonly detected and abundant Chlorobornane was “P4” (2-exo,3-endo,5-exo,6-endo,8,8,9,10,10-
Nonachlorobornane). The Hepta- and Nona- chlorinated homologues were the most commonly detected
homologues.
The total toxaphene levels in burbot from Stuart, Kamloops and Nicola lakes were similar to the Yukon lakes,
which displayed low biomagnification of toxaphene by fish such as burbot. The levels of toxaphene in Moose
Lake. was about half that measured in Lake Laberge, which displayed a high biomagnification because its food
chain length is longer than the other Yukon lakes in the study. Measuring stable nitrogen isotope ratios in our
burbot samples to determine food chain position is required before the relatively high levels in Moose Lake
burbot can be attributed to a long food chain or to a local source of toxaphene.
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