Anatomy of a Perchlorate Plume Associated to Ordnance Destruction
Bibliographic record
Abstract
Past studies conducted at CFAD Dundurn (Canadian Forces Ammunition Depot – Dundurn) indicated a minor accumulation of munitions’ residues either in the surface soil and groundwater, with a few exceptions, including perchlorate, which travelled to the groundwater resulting in an important plume. The perchlorate plume moves to the west with a velocity around 7.5 m/y and sink deeper in the aquifer at a velocity of 0.3 m/y. Considering the geological/hydrogeological context in Dundurn, it would take more than 700 years to reach the limit of the property (Dakota First Nation land). In 2023, the mass flux was estimated at 258 g/y which is half than previous years (2020-2022) on the North-South transect. The maximum perchlorate mass discharge (26% of the total flux) is recorded in a well at depth and is related to a high perchlorate concentration and a high hydraulic conductivity (K). K values spread over three order of magnitude (10-4 to 10-7 m/s) at the site and increased with depth. Low K values on the upper part of the aquifer allows the plume to sink. Tracer tests allowed to indicate that the geology of the site is heterogeneous and more complex than anticipated. An effective porosity of 0.32 was measured. This value can be used for the design of an is situ remediation technic of the plume. The 50-hour pumping test at 13 L/min confirms a global hydraulic conductivity value of 10-4 m/s for the aquifer in this vicinity, a radius of influence of 23 m and a capture zone that extended on 220 m. This information can be used for the design of a pump and treat system to capture the perchlorate plume. The meteorological data from the Saskatoon weather station RCS (35 km from the site) show that precipitations decreased from 400 mm to 200 mm over the last 11 years (2012-2023). The precipitation recorded at the site station is around 65 mm in 2023 indicating a desertic climate (with precipitation <100 mm). The site's desert conditions, lack of nearby receptors (natural or man-made) and low population density make it an excellent location for ordnance destruction.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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 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".