Environmental Geochemistry of Potentially Toxic Metals in Phosphate Rocks, Products, and Their Wastes in the Algerian Phosphate Mining Area (Tébessa, NE Algeria)
Bibliographic record
Abstract
This study is focused on the environmental geochemistry of potentially toxic metals (PTMs)-bearing products and wastes in a mining area in Djebel Onk (NE Algeria) and their potential ecological and health risk assessment. Representative samples from (i) commercial products and (ii) grain size classes of wastes were mineralogically characterized using X-ray diffraction. The major and PTMs elements in the samples were chemically analyzed via ICP-AES and ICP-MS, respectively. The results reveal that the samples were mostly composed of carbonate fluorapatite (P2O5 > 24 wt %) and yielded PTM concentrations within the average range of phosphorites in neighboring countries and worldwide deposits as well. The concentrations of V, Cd, As, Ni, and Pb in the products were found to be within the acceptable values according to various standards, such as the Canadian and German Fertilizer Ordinance policies. Geochemically, PTMs distribution is linked to the main sub-composition of phosphate rock (apatite, clay, and dolomite). The Enrichment Factors (EF) display very-high-to-extremely-high enrichment of PTMs (Cr, Zn, As, Sr, Mo, Cd, Sb, Tl, Th, and U), while V, Co, Cu, Ni, Zr, Ga, Nb, and Pb show minor and moderate-to-high enrichments. Among all the PTMs, Cd, Tl, and U display a very high ecological risk (PERI) and contribute most to the total risk index (RI). The human health risk assessment of PTMs represented by the Hazard Index (HI) indicates that the non-carcinogenic risks are below the threshold values (HI < 1), while the HI values are higher for children than they are for adults. However, the cancer index (life time cancer risk) for Cr, Ni, As, and Cd for children and Cd for adults is greater than the acceptable threshold. These results are useful for phosphate beneficiation via removing these PTMs from the commercial product for efficient waste management.
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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) | 0.000 | 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".