Historic Atmospheric Organochlorine Pesticide and Halogenated Industrial Compound Inputs to Glacier Ice Cores in Antarctica and the Arctic
Bibliographic record
Abstract
Ice cores collected from polar ice sheets at Site M, Dronning Maud Land, East Antarctica (Lat 75.00 S, Long 15.00 E), and Holtedahlfonna, Svalbard (Lat 79.13 N, Long 13.27 E), were analyzed for a net deposition of 25 organochlorine pesticides (OCPs) and 16 organohalogen (chlorine/bromine) industrial compounds (OHICs). Long-range atmospheric transport (LRAT) delivers contaminants to both sites, but the processes are different: Site M is affected by subsidence of air from the stratosphere to the Antarctic Plateau, while Holtedahlfonna is affected by air moving through the free troposphere. The sample from Site M is a composite core covering 1958–2000, while the Holtedahlfonna sample includes a historic record from 1953 to 2005 in six discrete samples. The five highest OCPs at Site M were chlorpyrifos, trans-chlordane, 4,4′-dichlorodiphenyl trichloroethane (DDT), ß-hexachlorocyclohexane (HCH), and dieldrin, while at Holtedahlfonna, they were chlorpyrifos, γ-HCH, α-HCH, ß-HCH, and dieldrin. The five most abundant OHICs at Site M were three dichlorobenzenes (diCBs), 1,3-diCB, 1,4-diCB, 1,2-diCB, and 1,3,5-trichlorobenzene and 1,2,4,5-tetrachlorobenzene (tetraCB) and at Holtedahlfonna, they were the same three diCB, pentachloroanisole (PCA), and 1,2,4,5-tetraCB. Of the OHICs, only hexachlorobutadiene, PCA, and hexachlorobenzene were found in all six Holtedahlfonna ice-core segments. Principal component analysis of the OCP percent of total flux values shows no similar variance among the Holtedahlfonna core segments, the whole-core value, or Site M. The principal component analysis of OHIC shows no consistent variance among any of the samples except for two Holtedahlfonna segments with the lowest OHIC values in the core.
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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 | 0.001 |
| 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) | 0.000 | 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".