Bibliographic record
Abstract
Annual source indicators for lead have dropped drastically with the phasing out of tetra ethyl lead as a fuel additive more than 15 years ago. Deposited lead concentrations along highway corridors continue to exceed the standard set in the B.C. Contaminated Site Regulation. The Ministry of Transportation and Highways is obliged to mitigate risks, without consideration of the mobility of the contaminant. This project was to determine whether it is acceptable to leave lead-contaminated roadside soil in place. Lead accumulations up to 1628 mg/kg were found in the highway soils. Lead contamination was found mainly in the top 0.3 m surface soil, with Pb concentrations rapidly decreasing to the background level at a depth of 0.6 m. The top 0.3 m contains more organic material and has a high adsorption capacity. Highway soils were found to have 3–10 times higher adsorption capacity for lead than the amount currently deposited on site. Therefore, it is unlikely that adsorption capacity will be saturated in the near future. Batch desorption tests using H2O at pH 5.5 and a HNO3 solution of pH 4.0 as leaching solutions indicated leachant concentrations below 2 ppm with a detection limit of 0.1 ppm. Despite the high total Pb concentration found in the soil, all sample leachants were below the B.C. Environmental Drinking Water Standard (10 ppm in solution). These results suggest that Pb has very limited mobility in highway soil and leaving the Pb contaminated soil in place may be acceptable.
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 | 0.001 | 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) | 0.001 | 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".