PT09 Emerging Pollutants / Receptors
Exhibit Hall
8:00 AM - Tuesday
(PT138) Waste Products of Oilsands Mine Alter Sex Steroids in Exposed Fish.
Van Der Kraak, G1, Lister, A1, Nero, V2, Farwell, A2, Dixon, D2, 1 University of Guelph, Guelph, ON, Canada2 University of Waterloo, Guelph, ON, Canada
ABSTRACT- Oilsands mining by Syncrude Canada Ltd. (SCL) in northern Alberta generates the waste products: mature fine tailings (MFT) and tailings pond water (TPW). MFT is a toxic aqueous suspension of particles, organic acids, bitumen, and metals and TPW is a saline solution containing organic and inorganic contaminants. The purpose of this study was to examine the impact of MFT and TPW on reproductive steroid production in sexually mature goldfish, Carassius auratus over two sampling periods. The goldfish (12-15 per pond per sex) were caged for 19 days in experimental ponds (0.16 ha each) constructed on SCL land and lined with or without MFT and capped with or without TPW. Three ponds were used in the study: pond 1 (no MFT, no TPW), pond 3 (MFT, no TPW), and pond 5 (MFT, TPW). Plasma levels of sex steroids (testosterone and estradiol) of goldfish caged during a late stage of reproduction (September 2001) in ponds 3 and 5 were significantly (p<0.05) reduced compared with fish in pond 1. Conversely, cortisol levels of males from ponds 3 and 5 were significantly increased compared with pond 1 fish. Studies conducted during the middle of the reproductive cycle (June 2003), demonstrated significant reductions in estradiol of females and in testosterone of males caged in Pond 5 compared with Pond 1. To resemble pond conditions in a laboratory setting in June 2003, goldfish were exposed to varying concentrations of naphthenic acid extracts (NAE; 1.5, 3.0, 6.0 mg/L) for 7 days. In males, exposure to NAE caused a dose related decrease in T, and surprisingly, a marked elevation in E2 levels. Over two separate years we have demonstrated that plasma sex steroid levels are altered by constituents of oilsands effluents in the experimental ponds and these effects were more pronounced in Pond 5. The disruption in hormone synthesis found in fish held in the experimental ponds was not clearly observed in fish exposed to NAE. Further studies are required to identify the constituents of oilsands wastes responsible for the reproductive effects.
Key words: reproduction, oilsands, fish, stress