Exposure Trends and Half-lives of Per- and Polyfluoroalkyl Substances (PFAS) in Australian Firefighters

Abstract

BACKGROUND AND AIM: Per- and polyfluoroalkyl substances (PFASs) are persistent manmade compounds used in aqueous film forming foam (AFFF). The extensive use of AFFF has led to widespread environmental PFAS contamination and exposures to firefighters. The aim of this study is to determine PFAS blood serum concentration trends and apparent serum elimination half-lives in firefighters after the replacement of AFFF. METHODS: Current and former employees of an Australian corporation providing aviation firefighting services, where AFFF had been used in the past, were recruited to participate in this study. Special focus was placed on re-recruiting participants who had provided blood samples five years prior. Participants were asked to provide a blood sample and complete a questionnaire. Serum samples were analysed for 40 different PFASs using HP LC-MS/MS. RESULTS: A total of 799 participants provided blood samples. Of these, 130 previously provided blood serum five years prior. Mean serum concentrations of perfluorooctane sulfonate (PFOS, 27 ng/mL), perfluoroheptane sulfonate (PFHpS, 1.7 ng/mL) and perfluorohexane sulfonate (PFHxS, 14 ng/mL) were significantly higher than the levels in the general Australian population. Serum concentrations were associated with the use of PFOS/PFHxS based AFFF. Participants who commenced service after the replacement of this foam had serum concentrations similar to those in the general Australian population. Average individual apparent half-lives were estimated to be 5.0 years (perfluorooctanoic acid (PFOA)), 7.8 years (PFHxS), 7.4 years (PFHpS) and 6.5 years (PFOS). CONCLUSIONS: This study shows how workplace interventions such as replacement of AFFF, can benefit employees at risk of occupational exposure. KEYWORDS: Biological Monitoring Occupational Exposure Firefighters Follow-Up Studies Half-Life