Occurrence and Relationship of Organophosphorus Insecticides and Their Degradation Products in the Atmosphere in Western Canada Agricultural Regions
Bibliographic record
Abstract
This paper presents the atmospheric occurrence and seasonal variations of the most frequently detected organophosphorus insecticides (OPs) and their OP oxon degradation products at Bratt's Lake, Saskatchewan in the Canadian Prairies (April 2003 to March 2004, January-December, 2005) and at Abbotsford in the Lower Frazer Valley (LFV) of British Columbia from May 2004 to December, 2005. During 2005 there were 10 OPs, 8 OP oxons, and 6 other OP degradation products measured. The most frequently detected OPs were chlorpyrifos, malathion, and diazinon. At Bratt's Lake the highest atmospheric concentrations were observed for chlorpyrifos, with maximum concentrations observed during July and August in 2003 showing much higher concentrations than those from 2005. This was related to its usage for grasshopper control in the province. At Abbotsford, diazinon and malathion were observed in much higher atmospheric concentrations than chlorpyrifos. Concentrations reached maximum in spring for diazinon and summer for malathion. This study is the first reported study of seasonal variations of OP oxons with their parent OP. Chlorpyrifos oxon concentrations during July were generally low, indicating strong local source contributions. The chlorpyrifos oxon/chlorpyrifos ratio and diazinon oxon/diazinon ratio showed a strong seasonal variation with increasing ratio from spring to summer which was attributed to increasing sunlight hours. Malathion oxon/mathion at both sites was similar and relatively constant throughout the year. The oxon/thion ratio represents a good indicator of age of source or contributions from local versus regional atmospheric sources.
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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 | 0.001 |
| 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".