Determination of Soluble/Exchangeable Metals in Peri-urban Farmland (Ribeira dos Covões) of Central Portugal
Bibliographic record
Abstract
Heavy metal contamination of soil is widespread, and there is a potential risk of transferring toxic metals to agricultural crops, animals and humans. The total heavy metals content can indicate the extent of contamination, but this measure is not usually an accurate indication of the phyto-toxicity; therefore, a number of recent studies have investigated the bioavailable heavy metal fractions in soils and evaluated the phyto-toxic risks for humans. Soluble and exchangeable forms of metals in the soil are the fractions available for plants. The main purpose of the present study is to quantify the total and soluble/exchangeable fractions of heavy metals (Pb, Cr, Cu and Zn) in soils of peri-urban farmland in Portugal (Ribeira dos Coves). The results show that the total heavy metals content is greater than the soluble/exchangeable content, but no clear correlations were recorded: Pb -70.8 mg/kg vs. 16.7 mg/kg, Cr -25.0 mg/kg vs. 0.0 mg/kg, Zn -383.3 mg/kg vs. 0.0 mg/kg, Cu -183.3 mg/kg vs. 0.0 mg/kg in a horticultural garden (site 10), and; Pb -270.8 mg/kg vs. 79.0 mg/kg, Cr -25.0 mg/kg vs. 0.0 mg/kg, Zn -12.5 mg/kg vs. 0.0 mg/kg, Cu -33.3 mg/kg vs. 29.2 mg/kg in a backyard (site 18). It is possible that the use of a single extraction procedure, in the laboratory, may not provide a proper assessment of heavy metal forms, and it is therefore advisable to combine different extraction methods in order to correctly perform a risk-based evaluation.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".