Evaluating Legacy and Emerging PFAS in Human Blood Collected from 2003 to 2021

Per- and polyfluoroalkyl
substances (PFASs) are a class of manmade
chemicals linked to numerous health outcomes including cancers and
increased cholesterol. Consequently, legacy PFASs such as perfluorooctanesulfonic
acid (PFOS) and perfluorooctanoic acid (PFOA) have been voluntarily
phased out of production within the United States since the early
2000s. However, as replacements, emerging PFASs have been introduced
over the last 25 years. The presence and accumulation of these emerging
PFASs remains largely unexplored due to the complexity of their identification
and quantification. Here, we analyzed a unique set of serum samples
(n = 156) collected from 2003 to 2021 consisting
of three groups: an autoimmune proband, a healthy sibling, and an
unrelated control. Quantitative analyses revealed no discernible link
between PFAS exposure and autoimmune disease diagnosis; however, nontargeted
analysis revealed concerning temporal trends in emerging replacement
PFASs the significance of which is unknown. We detected a concerning
increase in the chlorinated PFOS-replacement 9Cl-PF3ONS and polyfluoroalkyl
phosphate species including 6:2 DiPAP and perfluoroalkyl phosphinic
acids (PFPis) in human serum across the US since 2003. In addition,
we documented the presence of a novel PFAS chloroperfluorononylphosphonic
acid (Cl-PFNPA) in human serum. These analyses provide an assessment
of how PFAS exposure has changed since 2003 while exploring potential
linkages to autoimmune diseases.