Ozonation degrades all detectable organic compound classes in oil sands process‐affected water; an application of high‐performance liquid chromatography/obitrap mass spectrometry
Bibliographic record
Abstract
RATIONALE: Surface mining of bitumen in Northern Alberta, Canada, results in large volumes of toxic oil sands process-affected water (OSPW) that must be contained in tailings ponds. Ozonation has shown great promise as an OSPW treatment process, by decreasing its toxicity and increasing its biodegradability, but the effect of ozonation on the thousands of dissolved organic chemical groups has not yet been examined. METHODS: Reversed-phase liquid chromatography with ultrahigh-resolution linear ion trap-orbitrap mass spectrometry was applied to the characterization of treated (utilized ozone doses of 20 and 50 mg O3/L) and untreated OSPW. The analysis was performed in positive and negative electrospray ionization modes for each sample (ESI(+)/ESI(-)). RESULTS: Semi-quantitative analysis of ozonated and unozonated samples allowed degradation to be monitored for naphthenic acids (i.e. O2 species in ESI(-) mode) and >2000 other organic species belonging to various heteroatom-containing classes: Ox (where x = 1 to 6), NOx (where x = 1 to 4), SOx (where x = 1 to 4), NO2 S, N, and S. No chlorinated byproducts were detected in any treated sample, but at the low dose (20 mg O3/L) some compound classes increased in abundance (e.g. the O5 class), indicating that they were formed as byproducts at faster rates than they were degraded. Nevertheless, all organic compound classes subsequently diminished at the higher dose (50 mg O3/L). For several Ox and SOx classes, species observed in ESI(+) mode (e.g. O2(+) species) were often more recalcitrant to ozonation than the corresponding species detected in ESI(-) mode (e.g. O2(-) species; naphthenic acids). CONCLUSIONS: Ozonation appears to be a very suitable treatment option for OSPW, but the more recalcitrant groups of compounds may help to explain the residual toxicity of ozonated OSPW. Analysis of OSPW constituents in both ionization modes is warranted in all future OSPW fate studies.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".