Occurrence and speciation of disinfection by-products in water and air of indoor swimming pools in the province of Quebec (Canada)
Bibliographic record
Abstract
Swimming pools’ workers are exposed to potentially high levels of water and air disinfection by-products (DBP) which actual health impacts (e.g., irritation, carcinogenicity, genotoxicity) are still unclear. In the course of a project intended to assess occupational exposure to these contaminants, we conducted a study aimed to measure both typical and emerging DBPs in 41 indoor pools (14 in Quebec City and 27 in Montreal). Each pool was visited once, usually during the times of public swim. They were investigated for i): water levelsof 6 Haloacetic acids (HAAs), 4 Trihalomethanes (THMs), 4 Haloacetonitriles (HANs), Chloropicrine (CPK), 2 Haloketones (HKs), and ii) air levels of Chloramines (CAM) and THMs. Overall, nearly 900 samples and 3500 analyses were carried out for this study. Water emerging DPBs, including HANs, CPK and HKs, were found in substantial levels compared to their concentrations into drinking water network, especially HANs which were approximately 10-times higher (mean±SD: 21.4±13.9µg/L). HAAs showed the highest levels (295±157µg/L), which is consistent with previously reported high accumulation of these non-volatile compounds in pool waters. While chloroform (TCM) is usually the most abundant THM in both water (37.9±25.7µg/L) and air (119.4±74.2µg/m3), we measured important levels of brominated THMs in both media in 18 swimming pools. Interestingly, in 9 of these swimming pools, the brominated THM levels were even predominant (75.7±23.0µg/L in water and 223.7±101.8µg/m3 in air). Air CAM levels vary highly between each pool (0.23±0.14µg/m3). Preliminary statistical analyses disclosed relatively good correlations between air and water levels for TCM (R= 0.66) and THMs (R= 0.60). This study will be followed in next months by a second campaign to assess worker’s exposure through biological exposure monitoring. [Supported by IRSST, Québec]
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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 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".