Bioaccumulation of 17α-Ethinylestradiol in Fish
Bibliographic record
Abstract
The active synthetic constituent of oral contraceptives 17α- ethinylestradiol (EE2)\nand its natural steroidal estrogen analogues are being released into the aquatic\nenvironment mainly via wastewater treatment plants (WWTPs). Although steroidal\nestrogens have been frequently reported in very low concentrations in the environment,\nthey have been placed at the top of the list of endocrine disrupting chemicals (EDCs) for\ntheir high estrogenic activity in non-target aquatic species like fish and frogs. Almost 30\nyears worth of intensive research has moved the problem of endocrine disruption in the\naquatic environment from being a hypothesis to a well-known cause-and-effect story.\nHowever, the fate and effects of many pharmaceuticals, including EE2, remain poorly\nunderstood. Thus, the main objective of this thesis was to investigate EE2\nbioaccumulation in fish by field and laboratory studies.\nAn optimized sample preparation and analytical method protocol was achieved to\ndetect EE2 in its biologically active form in whole fish tissue at trace levels (ng/g).\nShorthead redhorse suckers (ShRHS) (Moxostoma macrolepidotum) collected in\nproximity to a WWTP in the St. Clair River have significantly accumulated EE2 with an\naverage of 1.5 ng/g. EE2 bioaccumulation was limited to fish exhibiting intersex and with\ninduced vitellogenin (VTG). EE2 was absent in fish from a reference site. Positive\ncorrelations between EE2 and lipid content as well as "15N supported the hypothesis of\nEE2 bioaccumulation in wild ShRHSs. A wider survey was carried out to explore\npatterns of EE2 bioaccumulation in the pelagic and benthic food-wed of the St. Clair\nIV\nRiver, Ontario. In the WWTP effluents and nearby surface waters, EE2 levels were\nextremely low and below our method detection limits. All of the seven sampled species\nfrom different trophic levels and the sediment samples collected from the impacted sites\nand the reference sites did not have any measurable EE2 concentrations. A laboratory\ncontrolled study where male goldfish (Carassius auratus) were exposed to EE2 via water\nversus food demonstrated that fish can rapidly accumulate EE2 by both routes of\nexposure. The uptake constant for water was 45 h-1 and the bioconcentration factor for\nEE2 in fish was 377. The fast uptake rate of EE2 via water coincided with a much slower\nelimination rate constant of 0.0786 h-1. The assimilation efficiency of 0.106 for EE2 by\ngoldfish was determined by EE2 dietary exposure, which was used to predict EE2\naccumulation under different exposure scenarios. The work presented here was the first\ndemonstration of EE2 bioaccumulation in wild fish and the first to model EE2\nbioaccumulation from water and dietary exposure in laboratory-exposed fish.
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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) | 0.001 | 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".