Occupational PFAS burden in German firefighters: Associations with aqueous film-forming foam contact frequency

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are highly persistent and bioaccumulative chemicals used in numerous industrial applications, including aqueous film-forming foams (AFFF). Human PFAS exposure has been linked to dyslipidemia, reduced vaccine antibody responses, developmental effects and potential carcinogenicity. OBJECTIVE: To determine whether firefighters with frequent occupational AFFF contact exhibit higher internal PFAS concentrations than firefighters with little or no foam exposure. METHODS: In this observational study, 140 professional and avocational firefighters from five fire departments in the German Rhineland region were enrolled. Plasma concentrations of 27 PFAS were quantified using online SPE-LC/MS/MS. Participants completed a structured questionnaire capturing demographic characteristics, occupational history, AFFF contact frequency and potential confounders. Statistical analyses were performed using Generalized Linear Models (GLM) adjusted for relevant covariates. RESULTS: Six PFAS (PFHxS, PFHpS, PFOA, PFOS, PFNA and PFDA) were detected in all participants. Firefighters reporting more than 10 lifetime AFFF contacts had higher European Food Safety Authority (EFSA) sum (PFHxS + PFOA + PFOS + PFNA) concentrations (mean 5.69 ± 4.19 μg/L) than those with ≤10 contacts (mean 3.79 ± 1.73 μg/L). Age was positively associated with PFAS levels, whereas regular blood donation was associated with lower concentrations. BMI and ski-wax exposure showed no significant associations. CONCLUSIONS: Frequent occupational AFFF contact is associated with elevated internal PFAS concentrations in firefighters suggesting an exposure-biomarker relationship. While measured levels generally remain below international firefighter reference values, several surpassed the HBM-I health based guidance values of the German Human Biomonitoring commission. These findings highlight the need for further investigations into long-term health risks in occupationally exposed populations.