Pesticide Multiresidues in Waters of the Lower Fraser Valley, British Columbia, Canada. Part II. Groundwater
Bibliographic record
Abstract
In Part I of this work we presented pesticide levels in the surface waters of the Lower Fraser Valley (LFV) region of British Columbia, Canada. In Part II pesticide levels in the groundwater of the LFV are presented. During the period 2003 to 2005 a study was conducted to determine the occurrence and spatial distribution of 78 pesticides in the groundwater of the LFV. Samples were collected and analyzed from one reference, nine agricultural, one urban, and three urban-agriculture mixed sites. Overall 24 different pesticides were detected in the sites monitored. The maximum single pesticide concentration observed was for simazine (90 ng L(-1)) at one of the agricultural sites. All concentrations of pesticides detected in groundwater samples were below Canadian surface water quality criteria and below available drinking water quality criteria set by World Health Organization (WHO), Health Canada, USEPA, and the European Union (EU). Pesticide levels in surface and groundwater were compared in the Abbotsford area. Generally, a pesticide with a high groundwater concentration tended to also have a high surface water concentration (Simazine 29 ng L(-1) in groundwater and 58 ng L(-1) in surface water, atrazine 5.5 ng L(-1) in groundwater and 14 ng L(-1) in surface water). For pesticides that were detected above 1 ng L(-1) concentration the only exception to this was desethylatrazine that showed greater concentration in groundwater (2.2 ng L(-1)) than surface water (1.5 ng L(-1)). Herbicides were the predominant pesticides detected in the agricultural sites and insecticides were predominant in the urban sites. Pesticide data presented in this study provide reference levels for future pesticide monitoring programs in the region.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.005 | 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".