Occurrence and distribution of polycyclic aromatic hydrocarbons in the Egyptian aquatic environment
Bibliographic record
Abstract
Persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this study, water samples were collected during 2007-2008 from two catchment areas that represent two different models of the aquatic environment in Egypt (Rosetta branch as fresh water and El-Moheet drain as untreated/treated waste water). The distribution of 16 PAHs included in the US Environmental Protection Agency's (EPA) priority pollutant list was analyzed by gas chromatography/mass spectrometry (GC/MS). Total PAH concentrations varied from 242 to 732 ng/L in fresh water from the Rosetta branch with a mean value of 408 ng/L; and for waste water the concentrations were in the range 894 to 1979 ng/L with a mean value of 1476 ng/L. The PAH profiles were dominated by low molecular weight PAHs (two- and three-ring components) in all collected water samples. The origin of PAHs in both waste water and fresh water in these study areas may be from oil or sewage contamination. The total PAHs concentrations of untreated waste water decreased along the treatment process by about 30% at the Zenein waste water treatment plant. The levels of PAHs in waste water are relatively high, although lower than locations with known problems.
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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 | 0.002 | 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 | 0.001 |
| 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 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".