Temporal trends of organochlorine concentrations in umbilical cord blood of newborns from the lower north shore of the St. Lawrence river (Québec, Canada).
Bibliographic record
Abstract
This study describes the time trends of organochlorines [OCs; 14 polychlorinated biphenyls (PCBs) and 11 chlorinated pesticides] in umbilical cord plasma of newborns in a remote Canadian coastal population. We analyzed 408 cord blood samples collected between 1993 and 2000 for PCBs, chlordanes, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyltrichloroethylene (DDE), hexachlorobenzene (HCB), and n-3 fatty acids. We also gathered information on the mothers (age, past and present residence, ethnic group, use of tobacco during pregnancy, and breast-feeding during previous pregnancies). From 1993 to 2000, mean concentrations of PCBs, chlordanes, DDT/DDE, and HCB in cord blood decreased by 63%, 25%, 66%, and 69%, respectively (p < 0.0001). Multiple regression analysis with the year of birth as the main independent variable yielded a strong significant exponential decrease for all contaminants (in all age and ethnic groups). We detected no monthly or seasonal pattern. We used n-3 fatty acids concentration as a surrogate of maternal fish consumption. Fish consumption declined only slightly between 1993 and 2000, but this decrease did not contribute significantly to the reduction of OCs. These results show that prenatal exposure to persistent OCs has declined significantly between 1993 and 2000 in this population.
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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 | 0.000 |
| 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) | 0.008 | 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".