Geostatistical analysis of heavy metals in a one-hectare plot under natural vegetation in a serpentine area
Bibliographic record
Abstract
The objective of this study was to examine the spatial variability of selected heavy metals in a soil developed over serpentine. Both total and EDTA-extractable Fe, Mn, Cr, Ni, Cu, Zn and Co were determined in 53 samples, collected from the topsoil of a 1-ha forested plot. Naturally occurring soil Cr and Ni concentrations were much higher than critical limits for safety. Experimental semivariograms were computed and modelled by a nugget component plus a structure with autocorrelation ranges varying between 25 and 90 m. EDTA-extractable heavy metal contents exhibit a different spatial variation pattern from that of total contents, although Ni and Cu semivariograms present some similarities. The joint spatial variation for pairs of variables with significant correlation was also investigated. The nugget variances in the cross-semivariograms were not very different from those of individual semivariograms, suggesting heterogeneity within the shortest sampling interval. Semivariograms provided a clear description of the spatial structure of heavy metals and some insight into possible processes affecting their distribution. Kriging maps allowed the identification of small regions with distinct metal concentrations and confirmed the suitability of geostatistics for investigating processes controlling heavy metal variation. Isotopic cokriging performed better than kriging, but the gain for mapping purposes was limited. Key words: Serpentine, heavy metals, geostatistics, scaling, spatial variability
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 | 0.001 |
| 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 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".