Evidence for alternative exhaled elimination profiles of disinfection by‐products and potential markers of airway responses to swimming in a chlorinated pool environment

Chlorine‐based disinfectants protect pool water from pathogen contamination but produce potentially harmful halogenated disinfection by‐products (DBPs). This study characterized the bioaccumulation and elimination of exhaled DBPs post‐swimming and investigated changes in exhaled breath profiles associated with chlorinated pool exposure. Nineteen participants provided alveolar‐enriched breath samples prior to and 5, 90, 300, 510, and 600 minutes post‐swimming. Known DBPs associated with chlorinated water were quantitated by thermal desorption‐gas chromatography‐mass spectrometry. Two distinct exhaled DBP elimination profiles were observed. Most participants (84%) reported peak concentrations immediately post‐swimming that reduced exponentially. A sub‐group exhibited a previously unobserved and delayed washout profile with peak levels at 90 minutes post‐exposure. Metabolomic investigations tentatively identified two candidate biomarkers associated with swimming pool exposure, demonstrating an upregulation in the hours after exposure. These data demonstrated a hitherto undescribed exhaled DBP elimination profile in a small number of participants which contrasts previous findings of uniform accumulation and exponential elimination. This sub‐group which exhibited delayed peak‐exhaled concentrations suggests the uptake, processing, and immediate elimination of DBPs are not ubiquitous across individuals as previously understood. Additionally, non‐targeted metabolomics highlighted extended buildup of compounds tentatively associated with swimming in a chlorinated pool environment that may indicate airway responses to DBP exposure.