Ten-week exposure to treated sewage discharge has relatively minor, variable effects on reproductive behavior and sperm production in goldfish
Bibliographic record
Abstract
It is well established that effluent from many sewage treatment plants (STPs) possesses estrogenic properties; however, the biological significance of this estrogenicity to fish reproductive behavior and sperm production is unknown. This study tested the hypothesis that 10-week exposure to a STP effluent with well-established estrogenic properties compromises the reproductive vigor of mature goldfish by decreasing the intensity of their reproductive drive and sperm production. Male goldfish were exposed for 10 weeks to one of four treatments: well water, a solvent control, 50 ng/L estradiol (E2), or undiluted effluent from a major metropolitan STP. Two trials were conducted, one in the winter and one in the summer when the effluent was chlorinated. Exposure to effluent in both the summer and winter trials induced small, but nonsignificant, decreases in the frequency of male spawning behaviors but had no effect on sperm production. Exposure to E2 caused a clear reduction in spawning behavior in one trial while causing reduced sperm production in both trials. We conclude that the effect of effluent exposure from this STP on adult fish is likely to be relatively minor and that the effluent's estrogenic properties may vary over the course of the year.
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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".