EVALUATING A MEAT AND BONE MEAL BIOCHAR AMENDMENT FOR IMMOBILIZATION OF ZINC IN A SMELTER IMPACTED SOIL
Bibliographic record
Abstract
Non-ferrous smelter emissions have prompted revegetation efforts near the border towns of Flin Flon, Manitoba and Creighton, Saskatchewan to facilitate regrowth of the surrounding boreal forest. Previously, several soil amendments were tested for plant response in soils from the smelter-impacted area and one amendment, a pyrolyzed meat and bone meal (MBM) biochar, was of particular interest because of its potential to immobilize Zn. \nHydroxyapatite (HAP), with a small degree of carbonate substitution, was identified as the major component of the MBM biochar. The solubility of this Ca-mineral was pH dependent, with dissolution occurring at pH 6.3; consequently, adsorption experiments were performed at a slightly lower pH (6.1 ± 0.1). Zinc adsorption kinetics were bi-phasic and could be modeled using the Elovich equation, suggesting a diffusion limited reaction likely related to material aggregation. Adsorption also was modeled using the Langmuir equation, which indicated a moderate affinity of the biochar for Zn and an adsorption maximum of 0.650 mmol Zn g-1. Synchrotron-based Zn K-edge x-ray absorption spectroscopy (XAS) indicated an inner-sphere monodentate, tetrahedral bonding of Zn to phosphate groups in the MBM biochar. This was consistent with Zn adsorbed to a HAP standard, indicating that the same sorption mechanism was involved.\nThe ability of MBM biochar to affect Zn speciation in soils was investigated using four soils from four locations in the smelter-impacted region around Flin Flon. A 1:10 (w/w) mixture of the MBM and soil was suspended in 200-mL deionized water (pH 6.1 ± 0.1) and equilibrated for 30 d. Whereas all the soils showed a decrease in extractable Zn following equilibration, only one exhibited a change in Zn speciation—with ca. 25% of the Zn adsorbed onto the MBM biochar. Ore-derived minerals were present in all soils and strong backscattering made identification of minor Zn species difficult. However, using microprobe-based x-ray absorption near edge structure (XANES) spectroscopy, several minor Zn species were identified; including hopeite, a ZnPO4 mineral. The presence of both hopeite and adsorbed Zn are indicative of a direct Zn-phosphate reaction. These results indicate that, under certain condition, MBM biochar can be an effective soil amendment.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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".