Co-existence of industrial organic contaminant plumes with municipal water supply wells in fractured rock aquifers
Bibliographic record
Abstract
Long-term studies combining research and conventional methods are being conducted at DNAPL sites where the organic contaminant plumes co-exist in the same fractured sedimentary rock aquifer with municipal water supply wells. Two of the research sites overlay the horizontally layered, Silurian dolostone aquifer. The Cambridge site has a metolachlor pesticide plume detected nearly 1 km down-gradient at a municipal supply well 20 years after spills occurred. The Guelph site plume is TCE. The plumes were characterized in detail using high-resolution methods for identifying hydraulically active fractures and variable matrix conditions. The 3-D plume concentration characteristics have been monitored for more than a decade using depth-discrete multilevel systems. The plumes have evolved to nearly stationary position (steady-state) after three decades due to the combined effects of diffusion and sorption in the matrix with dispersion in a dense network of well-connected fractures. Degradation occurs in each of the plumes but is a secondary factor in terms of current plume extents. These research studies show that high resolution monitoring can be used to inform site conceptual models and decision-making by municipalities and regulatory agencies to allow these plumes to coexist within or proximal to municipal or private well fields without imposing excessive or arbitrary demands for subsurface source removal (i.e. remediation) or well abandonment.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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 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".