Assessment of the Reproductive-Endocrine Disrupting Potential of Chlorine Dioxide Oxidation Products of Plant Sterols
Bibliographic record
Abstract
This study examined the hypothesis that chlorine dioxide bleaching used in pulp and paper production causes the formation of reproductive-endocrine disrupting compounds from plant sterols. This was tested by conducting a laboratory simulation of the chlorine dioxide oxidation of two plant sterols, beta-sitosterol and stigmasterol. Oxidation products of the plant sterol beta-sitosterol were purified and identified and found to be cholestan-24-ethyl-3-one, 4-cholestene-24-ethyl-3-one, and 4-cholestene-24-ethyl-3,6-dione. The first two compounds were found in a number of pulp and paper effluents and biosolids. The sterols and their oxidation products were tested in vitro using bioassays for androgenicity and estrogenicity. A 28 d in vivo bioassay was employed to examine masculinization in female mosquitofish. In vitro bioassays revealed little estrogenic activity in the parent sterols or in mixtures of their oxidation products. Androgenic activity as measured by the androgen receptor binding bioassay was in the order of 19-96 microg/g testosterone equivalents but with no increase or decrease with chlorine dioxide oxidation. The mosquitofish bioassay did not show significant masculinization for any of the preparations tested. A number of androstane steroids were identified in the sterols tested, however, those compounds could only account for a small fraction of the androgenic activity in the sterols. It was clear that the parent sterols were not themselves acting as androgens in the bioassays used. This study indicated that chlorine dioxide oxidation of sterols produced predominantly oxidized sterols that were not likely to act through androgenic or estrogenic mechanisms.
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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 | 0.000 |
| 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".