The temporal distribution, source and potential toxicity of polycyclic aromatic hydrocarbons in a sediment core from an urban lake in Wuhan, China
Bibliographic record
Abstract
The urban lakes in China, especially those with relatively small areas and closed watersheds, have suffered from serious pollution and are at a high risk of eutrophication due to the small amount of concern given to them. The temporal distribution profile, source apportionment and potential toxicity of parent polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs (APAHs) in a sediment core from an urban shallow lake with the above specifications, in the middle and lower reaches of the Yangtze River, China, were investigated in the present study. Parent PAHs, especially 4-6 ring ones, were dominant in the sediment core. The vertical profiles of 16 anthropogenic US Environmental Protection Agency (EPA) priority PAHs increased from a depth of 50 cm to 30 cm, then slightly decreased to the surface. However, biogenic perylene content decreased from bottom to surface. Most of the APAHs increased in concentration from bottom to surface. Source apportionment of EPA PAHs indicated the pyrogenic source was dominant in the sediment core. The domestic combustion of bituminous coal, coal tar and biomass can be identified as the main factors responsible for this. Toxicity assessment of selected parent PAHs demonstrated that benzo(a)pyrene accounted for the largest part of the toxic equivalent quantity (TEQ), and PAHs in the studied area possibly imposed adverse biological effects, especially for benthic organisms. Therefore, action should be taken to prevent an increase in the contamination from PAHs in the studied area, as well as in similar urban lakes in China, based on the specificity of individual watersheds.
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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 | 0.000 | 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 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".