Role of the water main in lead service line replacement: A utility case study
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
To understand the role of water mains in lead and iron release following lead service line (LSL) replacement, samples were collected from the tap water of 28 homes in Halifax, N.S., after a minimum 6‐h stagnation. In full replacements, average lead concentrations in service lines connected to cast‐iron mains with three different maintenance conditions—pigged, pigged and lined, and not pigged or lined—were 31.5±11.0, 3.3±2.3, and 3.7±2.7 μg/L, respectively, compared with 0.58±0.2 μg/L for ductile‐iron mains. In partial replacements, average lead concentrations were 63.09±30.9, 14.60±2.9, and 6.82±3.3 μg/L, respectively, for the three cast‐iron main conditions, compared with 8.5±3.1 μg/L for ductile‐iron mains. Adsorption of lead on iron corrosion scales dissolved or dislodged from tuberculated mains could account for the higher lead release observed. In this study, full replacement LSLs connected to ductile‐iron mains had the lowest lead concentrations.
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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 | 0.000 |
| 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 it