DDT, its Metabolites, and PAHs in Soils and Sediments from Cootes Paradise
Bibliographic record
Abstract
Cootes Paradise, located in Hamilton, Ontario, Canada is a 450-acre wetland marsh and acts as an important habitat for local species of plants, fish, reptiles, birds, and mammals. Recent detection of the legacy insecticide dichlorodiphenyltrichloroethane (DDT) within the tissue of frogs from Cootes Paradise highlighted a potential threat to ecological health and sparked new research into their habitat. Alongside these legacy contaminants, the City of Hamilton is a large metropolitan area with a storied industrial history, leading to a reputation of poor air quality and sediment contaminated with polycyclic aromatic hydrocarbons (PAHs). This research aimed to further expand the body of knowledge on contamination of DDT and its metabolites DDD and DDE within the watershed of Cootes Paradise, as well as begin to assess the extent of PAH contamination by analyzing the presence of the US Environmental Protection Agency’s (EPA) 16 Priority Pollutant PAHs. Results of this study further demonstrate that DDT, DDD, and DDE persist in the topsoil of areas adjacent to the main waterbody of Cootes Paradise. Sampling areas were chosen using ArcGIS Pro, based on the slope of the area as well as the proximity to the water of Cootes Paradise. 12 topsoil samples consisting of 0 to 10 centimeter and 10-to-20-centimeter soil intervals, and two sediment cores were sampled, and extracted and analyzed following a modified EPA organochlorine method. DDD and DDE were primarily observed in samples with high organic carbon content, indicating that degradation is likely associated with carbon content. Contamination of DDx also was the highest along the Southern shores, with a decrease in total DDx concentration and metabolite presence as you move North through Cootes Paradise. PAH contamination was consistent throughout marsh soil and sediment samples with comparable proportions of the 16 analyzed PAHs throughout sampling areas. This suggests one common source of PAH contamination acting as an input to Cootes Paradise. Diagnostic ratio data are indicative of sources such as industrial emissions; however, it is likely that mixing of vehicular emissions also occurs before PAHs are ultimately deposited to the marsh.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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 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".