Bibliographic record
Abstract
Septic systems in lakeshore environments oft en occur where thin soils overlie bedrock and, consequently, fi lter beds may be constructed of imported fi lter sand. Th e objective of this study was to assess the mobility of wastewater phosphorus (P) in such a potentially vulnerable setting by examining a 20-yr-old domestic septic system located near Parry Sound, ON, Canada, where the fi lter bed is constructed of imported noncalcareous sand. Th e groundwater plume is acidic (pH 6.0) and has a zone of elevated PO4–P (up to 3.1 ± 1.7 mg L −1) below the tile lines but no elevated PO4–P is present beyond 5 m from the tile lines. Elevated concentrations of desorbable P (up to 137 mg kg−1) and acid-extractable P (up to 3210 mg kg−1) occur in the fi lter sand within 1 m below four of seven tile lines present and the total mass of excess acid-extractable P (39 kg) is similar to the estimated total lifetime P loading to the system (33 kg). Microprobe images reveal abundant Fe and Al-rich authigenic mineral coatings on the sand grains that are increasingly P rich (up to 10 % w/w P) near the tile lines. Additionally, 6 yr of monitoring data show that groundwater PO4 concentrations are not increasing. Th is indicates that mineral precipitation, not adsorption, dominates P immobilization at this site. Th is example of robust long-term P retention opens up the possibility of improving P removal in on-site treatment systems by prescribing specifi c sand types for fi lter bed construction.
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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 | 0.003 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.006 | 0.003 |
| Open science | 0.003 | 0.004 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.537 | 0.444 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".