Serum concentrations of per- and polyfluoroalkyl substances (PFAS) among men from the Danish fire services and Armed Forces.

Background: Per- and polyfluoralkyl substances (PFAS) have been used extensively in firefighting foams with resulting occupational exposure among firefighters.

Objective: To examine serum concentrations of PFAS among current and former employed and volunteer firefighters from the Danish fire services and Armed Forces.

Methods: During 2023-2024, 429 men from the Danish fire services and Armed Forces participated in the study. They were asked to provide a blood sample and fill in an online questionnaire. Concentrations of 15 PFAS were measured in serum. Measurements from the general population sampled in 2021 (the ENFORCE study) were used as reference. Associations between occupational factors and serum PFAS were assessed using multiple linear regression.

Results: Participants were from municipal fire services (n = 208), governmental fire services (n = 59), civilian airport fire services (n = 50), the air force (n = 98) and the navy (n = 14). Their median age was 50 years and median year of commencing service was 1999. While serum concentrations of PFAS among most participants were at level with those of the general population, civilian airport firefighters had higher serum concentrations of especially perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS) and perfluorooctane sulfonic acid (PFOS). Age-adjusted geometric means were 1.42 ng/mL for PFHxS, 0.28 ng/mL for PFHpS and 6.92 ng/mL for total PFOS among civilian airport firefighters.

Conclusion: Higher serum concentrations of PFHxS, PFHpS and PFOS among civilian airport firefighters likely reflected past occupational exposure to firefighting foam. Findings emphasized the importance of regulatory measures and substitution.