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CC BY-ND V4.0, Open Access
Thesis
Physiological Responses of Chinook Salmon to Wastewater Exposure
Washington State University
Master of Science (MS), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004581
Handle:
https://hdl.handle.net/2376/125350
Abstract
Wastewater treatment plants are known to release complex mixtures of chemicals into aquatic environments as wastewater effluent (WWE); however, the effects of these mixtures are still poorly understood. Chinook salmon (Oncorhynchus tshawytscha) are a culturally important species in the U.S. Pacific Northwest and are a vital food resource for critically endangered southern resident killer whales (Orcinus orca). Chinook abundances have declined drastically in this region and have struggled to recover. One source of stress likely contributing to this decline is chemical pollution from WWE. In this study, I investigated effects of WWE on juvenile Chinook health in a ten-day exposure to dilutions of WWE from 0.1% to 20%. At the end of the exposure, I measured endpoints associated with endocrine disruption, brain function, osmoregulation, stress, and metabolism. Of these endpoints, the only nonsignificant change was seen in osmoregulation as gill Na+/K+-ATPase (NKA) did not vary significantly between treatments. Exposure to WWE induced vitellogenesis, indicating significant disruption of the endocrine system. I also saw significant inhibition of glucose, a stress indicator, and brain NKA, an enzyme essential for neuronal signaling. Lastly, metabolism was affected as evidenced by altered total protein, cholesterol, and albumin in plasma, a drastic decrease in lipid content, and a significant increase in liver deformities. I compared contaminant concentrations in exposure water with effects concentrations from the literature for vitellogenin induction and brain NKA inhibition. For most contaminants measured in exposure water, concentrations were several orders of magnitude below effects concentrations in the literature. The exception was hormones, which were detected at similar concentrations in my study compared to concentrations in other studies that induced vitellogenin. While hormones were likely primarily responsible for the vitellogenin increase, other contaminants measured in this study could not explain the inhibition of brain NKA. Many toxicants in WWE are probably acting together to cause harmful effects in Chinook. Additionally, the effects seen in this short-term exposure to higher concentrations of WWE could be similar to chronic exposures to lower concentrations. This research highlights the need for improved wastewater treatment to improve aquatic health and help threatened species like Puget Sound Chinook salmon.
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Details
- Title
- Physiological Responses of Chinook Salmon to Wastewater Exposure
- Creators
- Suzanne Ball
- Contributors
- Jenifer McIntyre (Advisor)Alison Gardell (Committee Member)Anand Jayakaran (Committee Member)Courtney Gardner (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Agricultural, Human, and Natural Resource Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 116
- Identifiers
- 99900898740101842
- Language
- English
- Resource Type
- Thesis