Acute Sublethal Toxicities of 6PPD-Quinone to Juvenile Salmonids
| dc.contributor.advisor | Brinkmann, Markus | |
| dc.contributor.advisor | Janz, David | |
| dc.contributor.committeeMember | Hecker, Markus | |
| dc.contributor.committeeMember | Weber, Lynn | |
| dc.contributor.committeeMember | Alderman, Sarah | |
| dc.creator | Selinger, Summer J | |
| dc.creator.orcid | 0009-0008-5388-9903 | |
| dc.date.accessioned | 2025-02-24T14:42:43Z | |
| dc.date.available | 2025-02-24T14:42:43Z | |
| dc.date.copyright | 2024 | |
| dc.date.created | 2025-01 | |
| dc.date.issued | 2025-02-24 | |
| dc.date.submitted | January 2025 | |
| dc.date.updated | 2025-02-24T14:42:44Z | |
| dc.description.abstract | This thesis investigated the effects of N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-quinone), an environmental transformation product of the widely used rubber tire antioxidant 6PPD, on juvenile salmonids. Increasingly recognized as a significant environmental pollutant present in road runoff and surface waters, 6PPD-quinone is notorious for inducing acute lethality in select salmonid species at extremely low concentrations (≤1 μg/L). Conversely, other salmonid species show insensitivity, even when exposed to substantially higher concentrations (3.8-50 μg/L). Sensitive species exhibit distinctive symptoms and atypical swimming behaviour such as gasping, spiraling, increased ventilation, erratic movements, tumbling. and loss of equilibrium, indicating potential impacts on cardiorespiratory physiology. Despite these observations, this thesis is the first to characterize these effects in salmonids comprehensively. Unlike the predominant focus on acute toxicity in existing literature, this study primarily investigated sublethal toxicities. Specifically, it examined the impacts of 6PPD-quinone exposure on salmonids of varying sensitivity: two sensitive species, rainbow trout (Oncorhynchus mykiss) and lake trout (Salvelinus namaycush), and one tolerant species, Arctic char (Salvelinus alpinus). Fish were exposed to a solvent control or 0.59, 0.46, or 7.15 μg/L 6PPD-quinone, respectively, for 20-48 hours. In both rainbow trout and Arctic char, increases in standard metabolic rate were observed. Only rainbow trout showed a decrease in end systolic volume and an increase in passive ventricular filling, cardiac output, and PR interval length, indicating cardiac stimulation. The cardiorespiratory symptoms seen in sensitive species might be partly due to a significant increase in methemoglobin, impairing their ability to oxygenate tissues. In lake trout, 6PPD-quinone exposure impaired swimming performance, demonstrated by a decrease in critical swimming speed. Exposure also resulted in significant decreases in active metabolic rate, although no changes were observed in standard metabolic rate. Additionally, decreased concentrations of white muscle triglycerides of swam fish were also observed in lake trout. These findings suggest that environmentally relevant concentrations of 6PPD-quinone can disrupt aerobic metabolism, swimming performance, and cardiovascular function in salmonids, potentially affecting fish survival. The findings of this thesis provide crucial insights into the sublethal toxicities of 6PPD-quinone to juvenile salmonids, offering valuable information for ecological risk assessment. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/10388/16616 | |
| dc.language.iso | en | |
| dc.subject | Tire rubber antioxidant | |
| dc.subject | species-specific toxicity | |
| dc.subject | cardiotoxicity | |
| dc.subject | swim tunnel | |
| dc.subject | energy homeostasis | |
| dc.subject | metabolism | |
| dc.title | Acute Sublethal Toxicities of 6PPD-Quinone to Juvenile Salmonids | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Toxicology Centre | |
| thesis.degree.discipline | Toxicology | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.Sc.) |