Bibliographic record
Abstract
BACKGROUND: Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn) used in Canadian gasoline since 1976 as an antiknock agent and to improve octane rating. Combustion products of MMT are mainly a mixture of Mn phosphate and Mn sulfate. In 1997, the Canadian federal government adopted a law (C-29) which banned both the interprovincial trade and the importation for commercial purposes of manganese-based substances, including MMT. However, the government reworded this law in July 1998 so that manganese-based fuel additives were not included in the restrictions. MMT is now approved for use in Argentina, Australia, Bulgaria, the United States, France, Russia, and conditionally in New Zealand. Nevertheless, these countries are not using MMT intensively and they are waiting for strong evidence of the absence of effects on human health. Even after several years of use of MMT in Canada, many uncertainties remain. METHODS: Different methods were used in order to assess (1) environmental contamination and human exposure to the parental form of MMT, (2) nitrogen oxides (NO(x)) and carbon monoxide (CO) emissions associated with the use of MMT, and (3) qualitative and quantitative assessments of Mn emissions to the environment. RESULTS: The results provide timely information with regard to the impact of MMT on environmental/ecosystem Mn contamination in abiotic and biotic systems as well as on human exposure. Moreover, results raise major concerns with regard to public health effects related to exposure to Mn. CONCLUSIONS: Obviously, there is still an important lack of adequate toxicological information and further studies are needed to provide successful implementation of evidence-based risk assessment approaches.
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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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".