Partitioning of <sup>127</sup>I and <sup>129</sup>I in an unconfined glaciofluvial aquifer on the Canadian shield
Bibliographic record
Abstract
Summary At AECL – Chalk River Laboratories, Ontario, Canada solid, low-level radioactive wastes from industrial, academic and medical applications have been stored in trenches above unconsolidated sandy glacial tills and permeable very-fine to fine-grained sands overlying crystalline bedrock. The sandy aquifer system drains into a swamp comprised of approximately 3 m of sphagnum peat. A comprehensive field and analytical program, involving measurements of total iodine, 129I, tritium, 14C and 13C/12C ratios in groundwater and geologic materials (sands and peats), was initiated at this site to examine the partitioning of 127I and 129I amongst the various reservoirs in this system and the controlling factors. The maximum iodine concentration and 129I inside the groundwater contaminant plume at the recharge and discharge sites were 67.0 ng/ml and ∼8.3 × 1011 atoms/liter, and 32.4 ng/ml and ∼2.9 × 1011 atoms/liter, respectively, with positive correlations between iodine, 14C (0.82), and tritium (0.87). Maximum total iodine concentrations for in-plume, recharge-site sands and discharge-site peats were 190.1 µg/kg and 14100 µg/kg, respectively. 129I analyses on these same samples showed concentrations of 2.3 × 107 and 6.4 × 109 atoms/g of soil, respectively. K D values (concentration on porous medium/concentration in co-existing water) calculated from the contaminant plume data for 127I and 129I were 1.3 and 1.6 l/kg, respectively, at the recharge site and 486 and 93 l/kg, respectively, at the discharge area, indicating that both stable and radio-iodine are preferentially sorbed to the organic rich, aquifer materials at the discharge sites. Incremental leach experiments on these same geologic materials have borne out these differences, with 127I being more strongly sorbed than 129I, probably as the result of kinetically controlled sorption mechanisms and the differing residence times of stable and radio-iodine in this hydrologic regime.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".