Groundwater Quality, Geochemical Processes and Groundwater Evolution in the Chateauguay River Watershed, Quebec, Canada
Bibliographic record
Abstract
A hydrogeochemical study was carried out in the Quebec portion of the Chateauguay River watershed. The objective was to characterize the chemical composition of groundwater in order to evaluate its quality and assess geochemical variations related to the geological and hydrogeological settings. Bulk groundwater samples were collected from 144 wells distributed evenly over the study area. Nine of the wells were sampled with a multi-level packer system, for a total of 22 multi-level samples. Samples were analysed for a comprehensive set of chemical inorganic parameters: dissolved major, minor and trace constituents, bacterial content, and stable (δ2H, δ13C, δ18O) and radioactive (3H, 14C) isotopes. Major dissolved constituents Ca, Mg, Na, K, Cl, SO4 and HCO3– ions represent more than 92% of total dissolved solids and their concentrations seem controlled by both hydrogeological and geological factors. Most water quality problems are related to aesthetic standards for potable water use (hardness, total dissolved solids (TDS), Fe and Mn concentrations) and TDS and Cl for irrigation use. Analyses of tritium (3H) and 14C confirm the inferred recharge zones and indicate the presence of variable water ages. Groundwater shows a wide range of compositions as indicated by 12 water types defined on the basis of major ions with a weak variation of chemical composition with depth. The predominant water type, Ca-HCO3, occurs in most geological and hydrogeological settings. Principal Component Analysis (PCA) and geochemical graphs were used to identify the major processes that exert a control over the chemical composition of the groundwater. Approximately 80% of the geochemical variation can be explained by mixing between fresh recharge water with more saline water associated with the former Champlain Sea, which invaded the aquifer. Secondary processes are related to ion exchange and the potential dissolution of minerals. A cross-section along a major flow path shows that the geochemical evolution of groundwater leads to relations between water type groups, geochemical processes, and groundwater flow conditions. The hydrogeochemical conceptual model infers that carbonate dissolution during recharge leads to one end-member, a Ca-HCO3 type water, which further evolves along its flow path due through ion exchange and mixing with remnant Champlain Sea water (Na-Cl), the other end-member.
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 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".