Abstract: Local stratigraphy and groundwater chemistry in the Grand Pré region, Nova Scotia: contamination sources and mitigation strategies
Bibliographic record
Abstract
Grand Pre, Nova Scotia, is located in the AnnapolisCornwallis Valley, and is underlain by Carboniferous Horton Group sedimentary rocks that comprise the local groundwater aquifer. Two suites of 26 groundwater samples were collected two months apart and analyzed for the concentrations of 72 cations. In nine samples, the concentrations of the anions (Cl-, NO2, Br, NO3, SO4, and PO4) were also determined. Samples were analyzed by ACME Analytical Laboratories, Vancouver, British Columbia, using ICP mass spectrometry. Concentrations of uranium (U up to 0.0508 mg/L), iron (Fe up to 0.605 mg/L), selenium (Se up to 0.0277 mg/L), lead (Pb up to 0.0541mg/L), and manganese (Mn up to 2.2822 mg/L) exceed the maximum allowable concentrations defined by Health Canada in some wells. A natural source for these contaminants is likely. The source of U and Se is believed to be the peraluminous South Mountain Batholith granite, the source of clastic grains in the mineralogically immature Horton Group sedimentary rocks. Both highly permeable arkosic arenites (channel facies) and moderately permeable carbon-rich shales (overbank facies) serve as local aquifers. The different geochemical environments within these sedimentary facies control groundwater element mobility. Thermodynamic modelling and construction of pe/pH stability diagrams gives insight into the contaminant speciation and effects of facies stratigraphy on groundwater geochemistry. Preliminary results suggest that carbon-rich (reduced) facies in Horton Group sedimentary rocks result in conditions favourable to sequestration of uranium and selenium. The opposite is true for wells that derive their water from (oxidized) highly permeable channel sand facies. A review of published documents from provincial, federal, and international organizations, including the World Health Organization, provides information on specific groundwater management approaches and guideline development. Cooperation between the Nova Scotia Department of Environment and Labour and the residents of Grand Pre is necessary to create a strategy to mitigate the groundwater hazards in Grand Pre, and will also act as a framework for achieving desirable drinking water in similar communities.
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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 | 0.000 | 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) | 0.002 | 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".