Geospatial assessment of trace-level benzophenone-3 in a fish-bearing river using direct mass spectrometry
Bibliographic record
Abstract
Benzophenone-3 (2-hydroxy-4-methoxybenzophenone) is present in many sunscreens/cosmetics due to its UV-filtering properties, and has consequently been observed in recreational waters. There are growing concerns about endocrine disruption in aquatic organisms and broader impacts in freshwater and marine systems. Therefore, there is value in cost-effective, sensitive techniques that allow for high-density, spatiotemporal data to protect environmental health and inform public policy. Condensed phase membrane introduction mass spectrometry coupled to liquid electron ionization with in situ chemical ionization (CP-MIMS-LEI/CI) is a novel direct tandem mass spectrometry technique that fulfills these criteria, and was applied to direct measurements of benzophenone-3 in environmental water samples without any sample preparation. We report results that are sensitive (20 ng/L detection limit), reproducible (11% interday variability), and comparable to LC-MS/MS for environmental samples (n=4; 12-24% different). CP-MIMS-LEI/CI was applied to samples (n=33) from the Cowichan River and Cowichan Lake (British Columbia, Canada), an important fish-bearing system significant to First Nations culture, salmonid production, and recreation. The quantitative analysis afforded by CP-MIMS-LEI/CI enabled geospatial benzophenone-3 analysis, identifying elevated concentrations (>180 ng/L) associated with local recreational activity. LC-MS/MS measurements for samples from two locations suggest a correlation between the number of swimmers and benzophenone-3 concentrations (R2 = 0.88, 0.94).
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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 | 0.000 | 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) | 0.001 | 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".