Spatial variations in tap water isotopes across Canada: Tracing water from precipitation to distribution and assess regional water resources
Bibliographic record
Abstract
With global warming and increasing water use, tap water resources need sustainable management. We used hydrogen and oxygen isotope analyses in tap water (i.e., δ 2 H and δ 18 O values) to identify issues associated with tap water resources in Canada. We analyzed 576 summer tap samples collected from across Canada and 76 tap samples from three cities during different seasons and years. We classified the samples based on their sources: groundwater (Tap Groundwater ), river (Tap River ) and lake (Tap Lake ). δ 2 H values in tap water correlate strongly with values predicted for local precipitation across Canada with a stronger correlation for Tap Groundwater and Tap River than for Tap Lake. We then constructed water balance models to predict the δ 2 H of surface water across Canada, and validated them against Canadian stream δ 2 H data. δ 2 H values in tap water correlate strongly with values predicted for local surface water, however, the water balance models improved the predictability only for Tap River and Tap Lake and not for Tap Groundwater . Tap Groundwater δ 2 H values reflect the δ 2 H values of annually averaged precipitation, whereas Tap River and Tap Lake δ 2 H values reflect post-precipitation processes. We used the δ 2 H residuals between the observed and predicted δ 2 H values to assess regional processes influencing tap water δ 2 H values across Canada. Regionally, snow/glacier melt contributes to all tap sources around the Rockies. Tap waters are highly evaporated across Western Canada, irrespective of their sources. In the Great Lakes and East Coast regions, tap waters are evaporated in many localities, particularly those using surface reservoirs and lakes. We propose the use of these isotopic baselines as a way forward for the monitoring of tap water resources at different scales. These isotopic baselines also have valuable applications in human forensic studies in Canada.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".