Trends in the Distribution of PCBs Compared to PACs in Sediments and Mussels of Halifax Harbour
Bibliographic record
Abstract
Abstract Surficial sediments and blue mussels (Mytilus edulis) were collected around the perimeter of Halifax Harbour. Samples were analyzed for the presence of polychlorinated biphenyls (PCBs), ranging from mono- to decachloro congeners, and results compared to the presence of polycyclic aromatic compounds (PACs). The objective was to explore the relationship between contaminant profiles in sediments and in mussels, and the possibility of deducing their sources, patterns of deposition, circulation and bioavailability. IUPAC hexachlorobiphenyls 138/158/160/163 (unresolved) and 153/132/168 were the most abundant congeners in both sets of matrices, ranging in concentration between <0.5 to 46 and 4.5 to 25.5 ng/g (dry weight) in sediments and mussels, respectively. PCBs profiles point to a combination of commercial sources superimposed on some weathering. Biota-sediment accumulation factors (BSAF, concentration in mussels, dry weight/concentration in sediments, dry weight, and lipid/TOC normalized) varied throughout the harbour and per congener. Some similarities were observed between the most contaminated sites previously analyzed for PACs and presently analyzed for PCBs, while BSAF were highest at the entrance to the harbour, for PACs and PCBs.
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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 | 0.007 | 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".