REPRODUCTION IN FATHEAD MINNOWS (PIMEPHALES PROMELAS) FOLLOWING WATER OR SEDIMENT EXPOSURE TO A COMPLEX URANIUM MILLING EFFLUENT ELEVATED IN SELENIUM
type: CreativeWork
description: Northern Saskatchewan, Canada is home to a uranium milling operation that discharges a complex effluent containing elevated concentrations of nutrients, compounds and many metals including the metalloid selenium (Se). Selenium has the potential to bioaccumulate in aquatic systems even when water concentrations are low, which has resulted in the identification of Se as a constituent of concern in affected aquatic ecosystems. This research evaluated the effects of treated uranium milling effluent and contaminated sediment in isolation and in combination to determine the contribution and importance of each source to fathead minnow (Pimephales promelas) reproduction and survival. Identification of pathways of exposure is critical to the mitigation of any observed effects. Trios of fathead minnows were allocated to one of four treatments for 21-days where the following were evaluated: survival (adult and 5 day larval), larval deformities, reproductive effects (egg production, spawning events) and metal tissue burdens (muscle, ovary, eggs and larvae). In addition, Se speciation analysis was conducted on selected fish tissues. Effects were overwhelmingly effluent-mediated with little contribution observed due to the presence of contaminated sediments. The contaminated sediments tested were taken from the actual receiving environment and represented the sediment composition found in greatest abundance in areas characteristic of fathead minnow habitats. Results showed egg production significantly increased in the effluent treatments compared to the reference water treatments (p ≤ 0.05). Although egg production increased following effluent exposure, there was reduced hatching success by 23% (p = 0.001), and larval survival by 31% (p = 0.001) and a significant increase in skeletal deformities (i.e. scoliosis, lordosis) in 5 day old larvae by approximately 6-fold (p = 0.001) relative to control. Despite these effects on the offspring, when examined in an integrated manner relat…
abstract: Northern Saskatchewan, Canada is home to a uranium milling operation that discharges a complex effluent containing elevated concentrations of nutrients, compounds and many metals including the metalloid selenium (Se). Selenium has the potential to bioaccumulate in aquatic systems even when water concentrations are low, which has resulted in the identification of Se as a constituent of concern in affected aquatic ecosystems. This research evaluated the effects of treated uranium milling effluent and contaminated sediment in isolation and in combination to determine the contribution and importance of each source to fathead minnow (Pimephales promelas) reproduction and survival. Identification of pathways of exposure is critical to the mitigation of any observed effects. Trios of fathead minnows were allocated to one of four treatments for 21-days where the following were evaluated: survival (adult and 5 day larval), larval deformities, reproductive effects (egg production, spawning events) and metal tissue burdens (muscle, ovary, eggs and larvae). In addition, Se speciation analysis was conducted on selected fish tissues. Effects were overwhelmingly effluent-mediated with little contribution observed due to the presence of contaminated sediments. The contaminated sediments tested were taken from the actual receiving environment and represented the sediment composition found in greatest abundance in areas characteristic of fathead minnow habitats. Results showed egg production significantly increased in the effluent treatments compared to the reference water treatments (p ≤ 0.05). Although egg production increased following effluent exposure, there was reduced hatching success by 23% (p = 0.001), and larval survival by 31% (p = 0.001) and a significant increase in skeletal deformities (i.e. scoliosis, lordosis) in 5 day old larvae by approximately 6-fold (p = 0.001) relative to control. Despite these effects on the offspring, when examined in an integrated manner relat…
author: Driessnack, Melissa
language: eng
keywords: selenium, fathead minnow, complex effluent, reproduction, uranium mining, larval deformities
date published: 2012-02-22
date modified: 2026-07-24T04:27:04Z
provider: University of Saskatchewan
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Saskatchewan

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10388/ETD-2011-12-313