Effect of Rare Earth Element Mixtures on Daphnia magna
Bibliographic record
Abstract
Rare earth elements (REEs) are increasingly being used in modern technologies and as such, there is an increasing concern for the potential environmental risk associated with anthropogenic contamination. In addition to there being very little data available for individual REEs, there is also a lack of knowledge concerning mixtures. The objective of my study was to investigate the chronic effects of lanthanum (La) and yttrium (Y) as well as the acute effects of neodymium (Nd), praseodymium (Pr) and Y as a single metal and as a mixture to Daphnia magna. Standard 21-d chronic tests and 48-h single metal acute tests following U.S. EPA and Environment and Climate Change Canada methods were conducted in an artificial soft water medium with a hardness of 50 mg CaCO3/L and a pH of 6.8 with no added bicarbonate at 21°C. Daphnia neonates (<24h old) were used with immobility (acute), growth and reproduction (chronic) as endpoints. Mixture exposures were designed using a toxic unit (TU) approach, based on converting the EC50 concentrations to toxic units and applying a matrix isobologram approach. The dissolved 48-h EC50 for Y was 0.699 mg/L (95% CI of 0.602-0.802 mg/L), for Pr it was 0.689 mg/L (95% CI of 0.530 - 0.916 mg/L), and for Nd it was 0.332 mg/L (95% CI of 0.265 - 0.408 mg/L). The total 21-d EC10 and EC20 values were 35.42 µg/L and 44.83 µg/L for La and 32.62 µg/L and 56.37 µg/L for Y. Chronic mixture tests used combinations of 0.2 (EC10) and 0.4 (EC20) TUs and acute tests used combinations of 0.2, 0.4, and 0.6 (EC30) TUs to observe whether the responses would follow an additive interaction. La and Y had similar toxicities at chronic levels and La-Y mixture tests elicited a less than additive interaction. Nd had a significantly higher toxicity than Pr or Y and the ternary mixture of Nd, Pr, and Y elicited additive and more than additive mixture interactions. This project contributes data towards the knowledge available on the toxicity of REEs individually and as a mixture in aquatic environments.
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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 | 0.001 |
| 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".