Cores of aquitard sediment yield details about natural attenuation in gas condensate-contaminated groundwater.
Bibliographic record
Abstract
Natural attenuation processes in contaminated groundwater can be better understood when cores of unconsolidated sediment in contact with the groundwater are analysed for their chemical, microbiological, and mineral-ogical composition at the sub-metre to microscopic scale. This approach is demonstrated for a natural gas well site in Alberta, Canada, where a plume of gas condensate hydrocarbons has contaminated the vadose zone and shallow groundwater in an aquitard (clayey silt). Conventional monitoring wells indicated a dissolved hydrocarbon plume. Sampling and analyses of sediment cores provided detailed and quantitative information about the heterogeneous distribution of both: (a) hydrocarbon contamination, and (b) natural attenuation processes. These analyses indicated that microbial sulfate reduction has been a dominant process associated with natural attenuation of hydrocarbons in the saturated zone. This research supports an emerging concept that microbial sulfate reduction is a key, dominant terminal electron accepting process in hydrocarbon-contaminated groundwater at oil and gas sites in western Canada.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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".