Global transport rates and future prediction of hazardous materials: Pu and Cs – from Nagasaki to Canadian Arctic
Bibliographic record
Abstract
A historical man-made global pollution of hazardous materials occurred at Nagasaki, Japan on August 9, 1945 detonation of a plutonium (10–15 kg) atomic bomb. Recent advancements in analytical technology made it possible for artificial radionuclides released from the nuclear explosion to be detected in the Arctic ice core layer of 1945. The fission product, 137Cs (23.4 g or 7.44×1013 Bq), and unexpended fission material, 239+240Pu (8.8–13.8 kg or 2.22–3.49×1013 Bq), originating from the Nagasaki A-bomb were measured by collecting 10 ice cores on the Agassiz ice cap, Ellesmere Island, Canada. The deposition rates were 20 mBq/cm2 for 137Cs and 0.16 mBq/cm2 for 239+240Pu, originating from Nagasaki. Assuming the radionuclides, excluding the amount deposited as local fallout, are deposited evenly throughout the northern hemisphere, a rate of 67% of the expected amount of 137Cs arrived at the Arctic while 1.1% of 239+240Pu reached the Arctic. The results suggest that different transport mechanisms exist for these two hazardous contaminants in the global transport system. A non-reactive rare gas, such as neon and argon, can spread evenly throughout northern hemisphere, including Ellesmere island at the Canadian Arctic, while a reactive gas, sulfur dioxide (SO2) will not reach the ice cap. The measured global transport rates of 137Cs and 239+240Pu were 67% and 1.1%, respectively. These measured rates were for the historical man-made hazardous materials and probably obtained for the longest distance of global transport over 10,000 km. Assuming there was a consistency in climate for the next 10,000 years, the chronological anthropogenic deposits, mainly of 239+240Pu, could be detected in the ice layer between 97–98 m from the snow surface at 11,999 AD on the Agassiz ice cap. Even if there were no improvements in the radioactive analytical method used, the ice layers for the 1945–1980 period could still be easily identified with the present analytical technology. Hopefully this study will find a way to use our generation's artefacts for the benefit of our future descendants.
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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) | 0.001 | 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 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".