Assessment of per- and polyfluoroalkyl substances (PFAS) exposure in Korean firefighters by serum analysis

This study assessed serum concentrations of seven per- and polyfluoroalkyl substances (PFAS) in Korean firefighters and the general population to characterize exposure levels, compositional profiles, and associated demographic, occupational, and lifestyle factors. The median serum concentration of perfluorooctanoic acid (PFOA) was significantly higher in firefighters (6.60 ng/mL) than in the general population (3.84 ng/mL) (Mann-Whitney U test, p < 0.01). PFOA accounted for the largest proportion of total PFAS in firefighters, whereas perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) were more prominent in the general population. Principal component analysis showed substantial overlap between the groups, with PFOA and selected long-chain perfluoroalkyl carboxylic acids contributing more strongly to variability among firefighters. In firefighters, length of service was positively correlated with several PFAS in univariate analyses, while primary multivariable analyses showed positive associations with perfluorononanoic acid (PFNA) and PFHxS, although these associations were attenuated in sensitivity analyses using alternative covariate specifications. In the general population, selected associations with age, height, and walking or strolling time also persisted after adjustment. These findings indicate differences in PFAS exposure patterns and associated factors between the two groups and underscore the importance of considering occupational characteristics in exposure assessment and management.