Grant: Travel Awards - Institute Community Support

Background: Airborne hazards significantly contribute to respiratory diseases. In Canada, 15% of new lung cancer cases are linked to occupational exposures. Organophosphate esters (OPEs) raise concerns due to risks of not only cancer, but also respiratory and cardiovascular diseases. Silicone wristbands (WBs) are promising passive samplers for multi-route exposure assessment, strongly correlated to airborne exposure but with limited occupational validation. This study evaluates the correlation between WBs and internal OPE levels in firefighters, paramedics, and office workers. Method: Participants wore a WB for 24 hours and provided two urine samples (0h and 24h). Twelve urinary metabolites (mOPEs) and 13 OPEs from WBs were quantified; those detected in >50% of WBs and urine (0h and 24h) were analyzed. Urine mOPEs and WB OPEs were described and between-occupational group differences were examined using ANOVA. Correlation between urinary mOPEs and parent compounds (WBs) is also reported. Results: In total 40 firefighters, 12 paramedics and 13 office workers participated (78.5% male; mean age=41yrs). TPhP, EHDPP, tBPDP, TCEP, TCiPP, and TDCiPP, and their metabolites were detected in >50% of WB and urine samples. TPhP (GM=258.58[2.72] ng/WB) and DPhP (GM-D1=1.09[2.4], GM-D2=1.20[2.2] µg/g-creatinine) had the highest WB and urine levels, respectively. Levels tended to be higher among firefighters, but this did not always reach statistical significance. Among mOPEs (urine) and parent compounds (WBs), tb.PPP-tBPDP (r=0.50, p<0.001) and BDCiPP-TDCiPP (r=0.34, p=0.008) had moderate correlation. Conclusion: WBs had higher detection frequencies than urine samples, highlighting external exposure. Though firefighters tended to have higher levels, this was not consistent. Future analysis will explore how work-related activities contribute to these differences. The next phase will examine a broader Canadian workforce to identify additional high exposure groups.