Human Exposure to PFAS and Other Anthropogenic Organofluorine Chemicals in Tromsø between 1986 and 2015

Summary In the last century, there has been a dramatic increase in chemical production and number and diversity of chemicals produced. Especially, organofluorine chemistry has increased its importance due to applications in pharmaceuticals, agrochemicals, refrigerant gases and in consumer products and industry with fluoropolymers and per- and polyfluoroalkyl substances (PFAS). PFAS are receiving international attention due to ubiquitous detection in the environment and in humans, their persistence and potential health and environmental impacts. Due to these concerns, production of some PFAS has been reduced internationally and their human blood concentrations are declining globally. However, PFAS production shifted towards new chemistries. Since >4700 PFAS exist and there is growing evidence about the presence of unknown organofluorine in human blood, there are concerns about PFAS human exposure underestimation. The overall thesis aim was to improve the description of PFAS and organofluorine exposure over three decades (1986-2015), covering a relevant timeframe for PFAS legislation and production changes. To achieve our goal, a new method to measure unknown PFAS in human blood had to be developed and we developed the total oxidizable precursors (TOP) assay for human serum. Pooled serum samples from the Tromsø Study collected in 1986, 2007 and 2015 were analysed using a fluorine mass-balance approach that included total fluorine (TF), extractable organic fluorine (EOF), target PFAS, suspect screening and, for the first time, TOP and fluorinated pharmaceuticals. Our study shows that TF concentrations did not change significantly between years, while EOF decreased between 1986-2007 and did not change between 2007-2015. However, the composition of EOF has been changing through years. While PFAS concentrations were highest in 2007, TOP concentrations were low and did not change between years and fluorinated pharmaceuticals and metabolites concentrations increased between 1986-2015. Further, suspect screening revealed only one additional PFAS with low concentrations.