Characterizing firefighter's exposure to over 130 SVOCs using silicone wristbands: A pilot study comparing on-duty and off-duty exposures

Firefighters are occupationally exposed to an array of hazardous chemicals, and these exposures have been linked to the higher rates of some cancer in firefighters. However, additional research that characterizes firefighters' exposure is needed to fully elucidate the impacts on health risks. In this pilot study, we used silicone wristbands to quantify off-duty and on-duty chemical exposures experienced by 20 firefighters in Durham, North Carolina. By using each firefighter's off-duty wristband to represent individual baseline exposures, we assessed occupation-related exposures (i.e. on-duty exposures). We also investigated the influence of responding to a fire event while on-duty. In total, 134 chemicals were quantified using both GC-MS and LC-MS/MS targeted methods. Seventy-one chemicals were detected in at least 50% of all silicone wristbands, including 7 PFAS, which to our knowledge, have not been reported in wristbands previously. Of these, phthalates were generally measured at the highest concentrations, followed by brominated flame retardants (BFRs) and organophosphate esters (OPEs). PFAS were measured at lower concentrations overall, but firefighter PFOS exposures while on-duty and responding to fires were 2.5 times higher than off-duty exposures. Exposure to polycyclic aromatic hydrocarbons (PAH), BFRs, and some OPEs were occupationally associated, with firefighters experiencing 0.5 to 8.5 times higher exposure while on-duty as compared to off-duty. PAH exposures were also higher for firefighters who respond to a fire than those who did not while on-duty. Additional research with a larger population of firefighters that builds upon this pilot investigation may further pinpoint exposure sources that may contribute to firefighters' risk for cancer, such as those from firefighter gear or directly from fires. This research demonstrates the utility of using silicone wristbands to quantify occupational exposure in firefighters and the ability to disentangle exposures that may be specific to fire events as opposed to other sources that firefighters might experience.