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(P542) Physiological and Biochemical responses of small fish exposed to Athabasca Oil Sands sediment.
Tetreault, Gerald*,1,2, McMaster, Mark2, Dixon, Douglas1, Joanne, Parrott2, 1 University of Waterloo, Waterloo, Ontario, Canada2 Environment Canada, Burlington, Ontario, Canada
ABSTRACT- Fish collected from the Alberta Athabasca Oil Sands watershed, including sites off the oil sands deposit itself, were examined. Within two tributaries, fish are either unexposed (reference), or exposed to naturally occurring oil sands related compounds. Wild fish collections and a laboratory sediment exposure were initiated to evaluate the influence of naturally occurring oil sands related compounds on reproductive function (gonadosomatic indices, fecundity, in vitro steroid production capacity) and hepatic responses (7-ethoxyresorufin-O-deethylase [EROD] activity). In vitro gonadal incubations demonstrated lower levels of steroid production at the tributary sites within the oil sands deposit. Hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity, as an indicator of exposure to oil sands related compounds, was elevated at these same sites. In the laboratory, slimy sculpin (Cottus cognatus) were exposed to sediment samples from the Steepbank River sites at concentrations of 10 or 20g/L (wet weight), for 4 and 8 d. For the purpose of evaluating EROD induction in fish exposed to oil sands sediment, a time period of 4 d was sufficient to induce what appeared to be maximum induction in this species by these sediments. The EROD activity measured in exposed fish was comparable to that measured in fish native to the oil sands area. This study as designed was not capable of predicting an altered ability of gonadal tissue of exposed fish to produce steroid hormones in vitro, as was demonstrated in the wild fish assessment of 1999 and 2000. Future development may further compromise the reproductive health of fish residing in the area.
Key words: Oil Sands, Small Sentinel Fish Species, Endocrine Disruption, Steroid Production
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