Cross-Species Evaluation of Bioaccumulation Thresholds for Air-Breathing Animals
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide In air-breathing organisms, an organic chemical’s susceptibility to elimination via urinary excretion and respiratory exhalation can be judged on the basis of the octanol–water partition ratio ( K OW ) and the octanol–air partition ratio ( K OA ), respectively. Current regulations specify that chemicals with K OW values of <10 2 and K OA values of <10 5 may be screened as non-bioaccumulative in air breathers. Here we used a model-based approach to evaluate whether these thresholds are consistent with a biomagnification factor of 1 for 141 different mammals, birds, and reptiles. Animals with lower rates of respiration (e.g., manatees and sloths) and those ingesting high-lipid diets (e.g., polar bears and carnivorous birds) were predicted to be able to biomagnify persistent chemicals with K OA values of <10 5 . This was also observed for several temperate reptiles due to their lower respiration rates and internal temperatures. Protective K OA thresholds were determined to be <10 4.85 for mammals, <10 4.60 for birds, <10 4.60 for reptiles at >25 °C, and <10 3.95 for reptiles at ≤25 °C. For all animals, urination alone was not efficient to prevent the biomagnification of any organic chemical. For chemicals with K OW values of <10 1, we found that biomagnification of persistent chemicals was constrained by the water–air partition ratio ( K WA ) rather than K OA . Differences in physiology may need to be considered in bioaccumulation assessments of air-breathing species.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".