Changes in serum perfluorooctane sulfonic acid and perfluorohexane sulfonic acid concentrations in firefighters accessing a voluntary perfluoroalkyl and polyfluoroalkyl substances reduction treatment program

BACKGROUND: In 2018/2019 a voluntary baseline biomonitoring survey (n = 916) identified firefighters at a fire station with substantially elevated serum perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) concentrations. The South Australian Metropolitan Fire Service (SAMFS) initiated a voluntary treatment program (VTP) to address the impact of these exposures (participants n = 19). At the conclusion of the VTP, a retrospective analysis of a de-identified and coded serum PFOS and PFHxS concentration spreadsheet was conducted independently of the VTP. OBJECTIVE: This study reports longitudinal changes in serum PFOS and PFHxS concentrations and compares participants accessing the VTP with an observational group that did not seek treatment. METHODS: The dataset included a treatment group (n = 19) and an observation group (n = 9). The treatment group was further subdivided into three subgroups: (1) plasma donation (n = 2), (2) cholestyramine administration (n = 12), and (3) a combination of plasma donation and cholestyramine administration (n = 5). Repeat samples identified participants' maximum and minimum serum PFOS and PFHxS concentrations. The calculations only included data from participants whose serum PFOS and PFHxS concentrations decreased. Apparent half-lives were estimated using one-compartment first-order elimination kinetics. The study did not conduct statistical comparisons; conclusions were drawn based on visual observations. RESULTS: The average change in serum concentration for the treatment group (PFOS: maximum decrease of 162 ng/mL, annual decrease of 41 %, with a half-life of 1.2 years; PFHxS: maximum decrease of 37 ng/mL, annual decrease of 32 %, with a half-life of 2.5 years) was compared with the observation group (PFOS: maximum decrease of 41 ng/mL, annual decrease of 12 %, with a half-life of 7.3 years; PFHxS: maximum decrease of 6 ng/mL, annual decrease of 10 %, with a half-life of 9.4 years). CONCLUSION: This study shows that participants who received treatment eliminated PFOS and PFHxS from their serum at a greater rate than the observation group.