Antioxidant Defence Response in Non-Target Fishes Following Pharmaceutical Wastewater Effluent Exposure
Bibliographic record
Abstract
The Grand River watershed extends throughout the majority of Southern Ontario with its \nfinal outlet at Lake Erie and accommodates thirty wastewater treatment plants (WWTP) with \nvarying types and degrees of treatment. Many WWTPs are currently unable to effectively \neliminate several contaminants of concern (CECs) from their final effluent, leading to measurable \nconcentrations in surface waters and ultimately chronically exposing aquatic species to mixtures \nof CECs. Exposures to CECs have reported impacts on oxidative stress, measurable through \nreactive oxygen species (ROS) and the antioxidant defense response which helps reduce the \ntoxicity of ROS generated molecules. This thesis aims to investigate the effects of WWTP effluent \non four Etheostoma (Darter) species endemic to the Grand River. Objectives were to examine if \nincreased antioxidative response markers are present in the brains of darters downstream from the \neffluent outfall compared to clean reference site upstream relative to the Waterloo, ON WWTP \nbetween two separate years (Fall 2020 and Fall 2021). This was assessed using transcriptional \nanalysis and enzymatic analysis of antioxidant enzymes (SOD, GPX, CAT) and an enzyme \ninvolved in serotonin synthesis (TPH). In fall 2020, significant differences in transcript expression \nof markers were found among sites and sexes in greenside darters (GSD) with SOD and CAT \nshowing increased expression downstream. Changes in transcript expression aligned with \nantioxidative enzyme activity where interactive effects with sex-related differences were observed \nin fish collected the Fall of 2020. In contrast, transcription markers measured in Fall 2021 were \nincreased upstream compared to species below the effluent outfall. \nField research is essential to understand subtle effects of wastewater effluent on non-target \nspecies, meaning a species that is not intentionally targeted by CECs. Using in vitro studies to \nsupplement in vivo studies provide a better understanding in the mechanisms for any observed \nphenotypic response. Therefore, this thesis also aimed to investigate the mechanism in alterations \nin antioxidant response by exposing isolated brain primary cell culture collected from zebrafish \nand darters to environmentally relevant concentrations of venlafaxine. Antioxidant response of the \ncells was assessed through cell viability, and antioxidant enzyme activity. Antioxidant enzyme \nactivity of SOD and CAT were both increased in zebrafish, RBD, and GSD isolated brain cultures \nexposed to 0.01-1 ug/L of venlafaxine. This response supplements the observed changes in \nantioxidant response of darters in the Grand River as they are chronically exposed to contaminated \neffluent containing notably high concentrations of pharmaceuticals. \nOverall, this thesis demonstrates how yearly varying abiotic factors such as observed \ntemperature increases in Fall 2021, species-specific differences, sex-differences, and venlafaxine \nhave roles in increased antioxidant response observed in non-target species. Continued \ninvestigation on the impacts of pharmaceutical exposures in non-target organisms is crucial to \nfurther the knowledge of WWTP effluent impacts.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".