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Lee E. Harding,¹ Megan L. Harris,² Craig R. Stephen,³ and John E. Elliott¹

¹Pacific Wildlife Research Centre, Canadian Wildlife Service, Environment Canada, Delta, British Columbia, Canada V4K 3N2
²Harris and van den Heuvel Independent Environmental Biologists, Fergus, Ontario, Canada N1M 1Z2
³Department of Health Care and Epidemiology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3

Abstract

We assessed chlorinated hydrocarbon contamination of mink and river otters on the Columbia and Fraser River systems of northwestern North America, in relation to morphological measures of condition. We obtained carcasses of mink and river otters from commercial trappers during the winters 1994-1995 and 1995-1996. Necropsies included evaluation of the following biological parameters: sex, body mass and length, age, thymus, heart, liver, lung, spleen, pancreas, kidney, gonad, omentum, adrenal gland and baculum masses, baculum length, and stomach contents. Livers were analyzed, individually or in pools, for residues of organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs) , dibenzo-p-dioxins, and dibenzofurans. Contaminant levels were relatively low compared to those documented in other North American populations, although they ranged higher than those detected during an earlier survey (1990-1992) of these regional populations. Body condition varied slightly among collection regions, but showed no relationship with contaminant burden. Mink from the upper Fraser River had less fat stores and also had some of the lowest OC contamination levels observed. Similarly, a few individuals with enlarged livers and kidneys had low contaminant levels. Although a few individual animals with gross abnormalities of reproductive systems did not show high levels of contamination, there was a significant negative correlation between total PCB concentrations (as Aroclor 1260) and baculum length in juvenile mink (r = 0.707 ; p = 0.033 ; n = 8) . The association of juvenile baculum length with eventual reproductive success is unknown, but further characterization of reproductive organ morphology and relationship to contaminants should be undertaken in a larger subset of these populations. Key words: baculum, mink, organochlorines, otter, polychlorinated biphenyls. Environ Health Perspect 107:141-147 (1999) . [Online 13 January 1999]

http://ehpnet1.niehs.nih.gov/docs/1999/107p141-147harding/ abstract.html

Address correspondence to J.E. Elliott, Pacific Wildlife Research Centre, Canadian Wildlife Service, Environment Canada, RR #1 Robertson Road, Delta, British Columbia, Canada V4K 3N2.

We thank the many trappers throughout the province for providing carcasses ; Marlene Machmer and Murray Lashmar for arranging the collection and shipment of carcasses from trappers ; Bruce Kay and Mark Sekala for generously providing laboratory equipment and space for dissection at the Pacific Environmental Science Center, and M. Wayland, C. Bishop, and C. Henny for their useful comments on an earlier version of the manuscript. Funding was provided by the Fraser River Action Plan and the Canadian Wildlife Service of Environment Canada and by the BC Ministry of Environment, Lands and Parks.

Received 28 May 1998 ; accepted 30 September 1998