The Effects of Diluted Bitumen on Developing Fathead Minnow (Pimephales Promelas)
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Authors
Alsaadi, Ftoon
Date
Type
thesis
Language
eng
Keyword
Dilbit , Access Western Blend , Cold Lake Blend , Polycyclic Aromatic Hydrocarbons (PAHs) , Blue Sac Disease , Oxidative Stress
Alternative Title
Abstract
Canada has experienced a significant increase in the transport of diluted bitumen (dilbit), a
predominant oil sands product that is created by combining bitumen with diluents derived from
oil-gas condensates and other proprietary compounds. The chemical composition of dilbit varies
to meet season and transport conditions. While the toxicological effects of a variety of crude and
refined oils are well studied, the toxicity of dilbit to fish embryos, which are immobile and thus at
a high a risk of exposure to oil in the event of a spill remain largely unknown. To fill this gap, this
study assessed the toxicity of two Winter dilbit blends, Access Western Blend (AWB) and Cold
Lake Blend (CLB), to fathead minnow (Pimephales promelas) embryos. Embryos were exposed
to a range of water accommodated fractions (WAF) and chemically enhanced WAF (CEWAF;
using Corexit®9500A as dispersant) for both AWB and CLB. After exposure, hatched fish were
assessed for blue sac disease (BSD) and expression of selected biomarker genes. Developmental
malformations were observed more frequently with increasing concentrations of AWB and CLB
in both WAF and CEWAF treatments and included tube heart, pericardial edema, and
craniofacial deformities. Levels of cyp1a and gst mRNA were elevated with increasing total
concentrations of polycyclic aromatic hydrocarbons in both AWB and CLB WAF and CEWAF
conditions. However, there were no significant changes in mRNA levels for p53, sod, cat, and
gsr. These results suggest that expression of cyp1a and gst may serve as biomarkers for dilbit
exposure in fathead minnow, furthering our understanding of dilbit-responsive indicators of
toxicity in fish species native to North America. This study is important as it utilizes the same
exposure methodology to examine the toxicity of two commonly used Canadian dilbits,
facilitating the comparison of dilbit toxicity.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.