Embryotoxicity of diluted bitumen applied to eggshells of wild double-crested cormorants and domestic chickens
Presentation Abstract
Breeding birds that become oiled may return to incubate their eggs, but even small quantities (≥1 mg) of conventional crude oils are embryotoxic when applied to the exterior of the eggshell. Therefore, we investigated whether an unconventional Alberta oil sands product, diluted bitumen (dilbit), was toxic to embryos of two species, domestic chickens (Gallus gallus) and wild double-crested cormorants (Phalacrocorax auritus). We incubated embryos in artificial egg incubators and applied various doses of lightly weathered dilbit (Cold Lake blend) ranging from 1 to 20 mg to the eggshells during early or late embryonic development. In both species, eggshell oiling with dilbit caused no significant decrease in embryo survival at sampling (80-85% embryonic development), and we found few effects on physiological endpoints related to growth, relative liver size (liver somatic index), and aerobic capacity. To investigate more subtle effects on liver function and metabolism associated with embryotoxicity, qPCR gene expression analyses on embryonic livers are underway and will be presented. We will also describe the physicochemical properties of the dilbit used in this study and its toxicity compared to similar studies with conventional crude oils. To date, this study indicates that even considerable amounts of lightly weathered dilbit transferred to the avian eggshell by incubating parents (up to 10-20 mg, approximately 9-19 µl) is unlikely to cause pre-hatch mortality in embryos of a domestic and wild avian species, although effects on gene expression are still under investigation.
Session Title
Session 1.3B: Contaminants in the Salish Sea: Wildlife exposure and impacts
Conference Track
Contaminants, Plastics, Microplastics, Toxicology & Stormwater
Conference Name
Salish Sea Ecosystem Conference (2020 : Online)
Document Type
Event
SSEC Identifier
2020_abstractID_4074
Start Date
21-4-2020 9:00 AM
End Date
22-4-2020 4:45 PM
Genre/Form
conference proceedings; presentations (communicative events)
Subjects – Topical (LCSH)
Birds--Eggs--Alberta; Environmental toxicology--Alberta; Birds--Effect of pollution on--Alberta
Geographic Coverage
Salish Sea (B.C. and Wash.); Alberta
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Format
application/pdf
Embryotoxicity of diluted bitumen applied to eggshells of wild double-crested cormorants and domestic chickens
Breeding birds that become oiled may return to incubate their eggs, but even small quantities (≥1 mg) of conventional crude oils are embryotoxic when applied to the exterior of the eggshell. Therefore, we investigated whether an unconventional Alberta oil sands product, diluted bitumen (dilbit), was toxic to embryos of two species, domestic chickens (Gallus gallus) and wild double-crested cormorants (Phalacrocorax auritus). We incubated embryos in artificial egg incubators and applied various doses of lightly weathered dilbit (Cold Lake blend) ranging from 1 to 20 mg to the eggshells during early or late embryonic development. In both species, eggshell oiling with dilbit caused no significant decrease in embryo survival at sampling (80-85% embryonic development), and we found few effects on physiological endpoints related to growth, relative liver size (liver somatic index), and aerobic capacity. To investigate more subtle effects on liver function and metabolism associated with embryotoxicity, qPCR gene expression analyses on embryonic livers are underway and will be presented. We will also describe the physicochemical properties of the dilbit used in this study and its toxicity compared to similar studies with conventional crude oils. To date, this study indicates that even considerable amounts of lightly weathered dilbit transferred to the avian eggshell by incubating parents (up to 10-20 mg, approximately 9-19 µl) is unlikely to cause pre-hatch mortality in embryos of a domestic and wild avian species, although effects on gene expression are still under investigation.
