Effect of pH and release® on two life stages of four anuran amphibians
Bibliographic record
Abstract
Using three native Canadian and one exotic anuran species, the interactive toxicity of pH and the forestry used-herbicide Release (triclopyr [3,5,6-trichloro-2-pyridl-oxyacetic acid]) was assessed. Embryonic and larval (Gosner 25) stages of Rana pipiens, Rana clamitans, Bufo americanus, and Xenopus laevis were exposed to treatments for at least 96 h in a static-renewal system using a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach to obtain confidence intervals. Consistent trends of greater toxicity with lower pH were observed, with the majority of models (five of seven models) showing significant (p < 0.05) inverse relations. Larval lethal concentration estimates were eight to twenty-three times less than those observed for embryos, indicating that the larval stages were more sensitive to treatments. Further, the median lethal concentration (LC50) values for the larvae were below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities for Release. Species sensitivity was similar, with an average larval 96-h LC50 of 0.89 mg acid equivalents (AE)/L at pH 5.5 and 1.6 mg AE/L at pH 7, suggesting that X. laevis is a reasonable surrogate for native amphibians in laboratory toxicity testing. For the embryo tests, R. pipiens were slightly less sensitive in comparison with the other three species. Based on a hazard quotient analysis (EEC/LC50 > 1) for the most sensitive larval life stages, higher tier ecotoxicological testing under more realistic environmental conditions is strongly recommended.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".