Groundwater flow dynamics and arsenic source characterization in an aquifer system of West Bengal, India
Bibliographic record
Abstract
Abstract Numerical groundwater flow modeling, reverse particle tracking, and environmental tracers are used to locate the source of geogenic As affecting an aquifer in West Bengal. The aquifer is hosted by point‐bar sands deposited in a meandering fluvial environment. Wells tapping the aquifer exhibit As concentrations up to 531 μg/L. High‐As groundwaters are recharged in ponds marking an abandoned river channel. The source of As is traced to the underlying fine‐grained channel‐fill sediments. Arsenic release within these sediments is accompanied by a concomitant release of Br and DOC indicating that these species may be decay products of natural organobromines codeposited along with As. Mass transfer of As to the dissolved phase and its flushing from source sediments are described using a simplified reactive solute transport model. Based on this model, a characteristic reaction time for mass transfer is estimated at 6.7 years. Average groundwater residence times in the source are estimated to have declined from 16.6 to 6.6 years with the advent of intensive irrigation pumping. The ratio of residence and reaction times, a Damköhler number, has declined correspondingly from 2.49 to 0.99, indicating a shift from transport to reaction rate limited As mobilization. Greater insight into the As problem in SE Asia may be achieved by shifting the focus of field investigations from aquifers to potential contamination sources in aquitards.
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".