The Acute Toxicity of Thulium to Hyalella Azteca and the Influence of Toxicity Modifying Factors.
Bibliographic record
Abstract
Abstract The demand for rare earth elements (REEs) is growing and as a result, environmental exposure is a concern. The objective of this research was to evaluate the acute toxicity of Tm to Hyalella azteca and to understand the potential for toxicity modification by dissolved organic matter (DOM) and the cations Ca 2+ , Mg 2+ and Na + . Standard methods were followed for 96 h static exposures in a medium with a hardness of 60 mg CaCO 3 /L, pH of 7.3 at 23°C. H azteca neonates (2-9 d of age) were used and in unmodified media the LC50 concentration was 3.4 µM (95% CI 2.9-3.9 µM; 573 µg/L (482-663)) based on measured dissolved concentrations at the end of the test. Tests done with different concentrations of Ca (0.25, 0.5 and 1.5 mM) did not show consistent trends and there was no clear evidence of a protective effect from Ca. Variations in Na (0.26, 0.5 and 1.6 mM) resulted in no significant changes in toxicity. Similarly, Mg (0.07, 0.14 and 0.4 mM) did not result in significant changes in LC50 values, except for a reduction in toxicity for measured total Tm at the lowest Mg concentration. Our results indicate that Tm toxicity is not influence by cationic competition (Ca, Na and Mg). Dissolved organic matter (sourced from Luther Marsh ON) offered significant protection against Tm toxicity. Additions over 3 mg DOC/L resulted in significantly increased LC50 values. This study contributes toward understanding the toxicity of Tm and the importance of considering dissolved organic matter in estimating the potential for environmental risk of REEs.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".