title: Fathead minnow (Pimephales promelas) reproduction is impaired in aged oil sands process-affected waters.
abstract: Large volumes of fluid tailings are generated during the extraction of bitumen from oil sands. As part of their reclamation plan, oil sands operators in Alberta propose to transfer these fluid tailings to end pit lakes and, over time, these are expected to develop lake habitats with productive capabilities comparable to natural lakes in the region. This study evaluates the potential impact of various oil sands process-affected waters (OSPW) on the reproduction of adult fathead minnow (Pimephales promelas) under laboratory conditions. Two separate assays with aged OPSW (>15 years) from the experimental ponds at Syncrude Canada Ltd. showed that water containing high concentrations of naphthenic acids (NAs; >25 mg/l) and elevated conductivity (>2000 μS/cm) completely inhibited spawning of fathead minnows and reduced male secondary sexual characteristics. Measurement of plasma sex steroid levels showed that male fathead minnows had lower concentrations of testosterone and 11-ketotestosterone whereas females had lower concentrations of 17β-estradiol. In a third assay, fathead minnows were first acclimated to the higher salinity conditions typical of OSPW for several weeks and then exposed to aged OSPW from Suncor Energy Inc. (NAs ∼40 mg/l and conductivity ∼2000 μS/cm). Spawning was significantly reduced in fathead minnows held in this effluent and male fathead minnows had lower concentrations of testosterone and 11-ketotestosterone. Collectively, these studies demonstrate that aged OSPW has the potential to negatively affect the reproductive physiology of fathead minnows and suggest that aquatic habitats with high NAs concentrations (>25 mg/l) and conductivities (>2000 μS/cm) would not be conducive for successful fish reproduction.
authors.affiliation: Department of Integrative Biology, University of Guelph, Guelph, ON, Canada. rkavanag@uoguelph.ca
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Kavanagh
authors.forename: Richard A
authors.initials: RA
authors.lastname: Frank
authors.forename: Ken D
authors.initials: KD
authors.lastname: Oakes
authors.forename: Mark R
authors.initials: MR
authors.lastname: Servos
authors.forename: Rozlyn F
authors.initials: RF
authors.lastname: Young
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Fedorak
authors.forename: Mike D
authors.initials: MD
authors.lastname: MacKinnon
authors.forename: Keith R
authors.initials: KR
authors.lastname: Solomon
authors.forename: D George
authors.initials: DG
authors.lastname: Dixon
authors.forename: Glen
authors.initials: G
authors.lastname: Van Der Kraak
mesh_terms: D000416:Alberta; D000704:Analysis of Variance; D000818:Animals; D002264:Carboxylic Acids / Q000032:analysis; D003530:Cyprinidae / Q000502:physiology*; D004553:Electric Conductivity; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006838:Hydrocarbons / Q000633:toxicity*; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D012098:Reproduction / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D002264:Carboxylic Acids; D012739:Gonadal Steroid Hormones; D006838:Hydrocarbons; D014874:Water Pollutants, Chemical; C006647:asphalt; C046170:naphthenic acid