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Record W77036666

Groundwater quality of crystalline bedrock aquifers in Norway

2002· article· en· W77036666 on OpenAlexaboutno aff
Bjørn Frengstad

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicGroundwater and Isotope Geochemistry
Canadian institutionsnot available
Fundersnot available
KeywordsAquiferGroundwaterBedrockGeologyLithologyCalciteGeochemistryUraniumCarbonatePrecambrianMineralogyEnvironmental chemistryChemistryGeomorphology
DOInot available

Abstract

fetched live from OpenAlex

In cooperation with the Geological Survey of Norway, the Norwegian Radiation Protection Authority, and local health authorities, 1604 groundwater samples collected from Precambrian and Palaeozoic crystalline bedrock aquifers and 72 groundwater samples from Quaternary aquifers were analysed for radon, pH, and major and minor elements. A representative subset of 476 samples was further analysed for trace elements at the Bundesanstalt fur Geowissenschaften und Rohstoffe, Germany.There appears to be a degree of lithological control on radon, fluoride, uranium and several other trace elements, shown as elevated contents in granitic groundwaters and depletions in anorthositic groundwaters. However, the concentration of a particular element in groundwater from a distinct lithology may span over 4 orders of magnitude, suggesting that other (kinetic and hydrodynamic) factors are equally important. A significant percentage of the analysed hard rock groundwaters do not fulfil the Norwegian standards for drinking water quality (the following as percentages of the n=476 subset), e.g. pH: 7%, Rn: 16%, F: 16%, Na: 1.5%, Fe: 14%, Mn: 26%, Al: 3.8%, Zn: 2.3%, Ba: 8%, As: 1.5 %, and U: 12 % (using US norm).pH values range from 5.6 to 9.8 in crystalline bedrock groundwaters with a predominance between 8.0 and 8.3, irrespective of rock type, suggesting buffering by the calcium-carbonate system. Geochemical modelling indicates that pH values above 8.3 may possibly be due to exhaustion of this buffering system by calcite precipitation, as well as by cation exchange against sodium. pH has also been shown to influence the concentrations of many elements in groundwater. Groundwaters from Quaternary sedimentary aquifers in Norway are generally less hydrochemically mature than their bedrock counterparts, with lower pH values and concentrations of Rn and F well below drinking water norms.Regular sampling of five boreholes during one year indicates that crystalline bedrock hydrogeochemistry is relatively stable over time, but intrusion of waters of short residence time and surficial nature (possibly due to poor well construction) can affect the water quality significantly. The groundwater chemistry of Norwegian hard rock aquifers resembles their Canadian and Fennoscandian counterparts, but differs systematically from lithologically comparable British aquifers. This suggests a distinct geochemical evolution for groundwaters from areas strongly affected by glacial erosion during Quaternary time. This may be related to the fact that aquifer host-rock is relatively chemically and physically unweathered in glacially scoured terrains, compared with deeper weathering profiles present in landscapes not recently glaciated.

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 imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.227
Threshold uncertainty score0.450

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.002
Science and technology studies0.0010.001
Scholarly communication0.0010.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

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.

Opus teacher head0.033
GPT teacher head0.225
Teacher spread0.193 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

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".

Quick stats

Citations7
Published2002
Admission routes1
Has abstractyes

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