Emerging Per- and Polyfluoroalkyl Substances in Tap Water from the American Healthy Homes Survey II

Humans experience widespread exposure to anthropogenic
per- and
polyfluoroalkyl substances (PFAS) through various media, which can
lead to a wide range of negative health impacts. Tap water is an important
source of exposure in communities with any degree of contamination
but routine or large-scale PFAS monitoring often depends on targeted
analytical methods limited to measuring specific PFAS. We analyzed
680 tap water samples from the American Healthy Homes Survey II for
PFAS using non-targeted analysis (NTA) to expand the range of detectable
PFAS. Based on detection frequency and relative abundance, about half
of the identified PFAS were found only by NTA. We identified (with
varying degrees of confidence) 75 distinct PFAS, including 57 exclusively
detected by NTA. The identified PFAS are members of seven structural
subclasses differentiated by their head groups and degree of fluorination.
Clustering analysis categorized the PFAS into four coabundance groups
dominated by specific PFAS subclasses. One group uniquely identified
by NTA contains zwitterionic PFAS and other PFAS transformation products
which are likely associated with aqueous firefighting foam contaminants
in a small number of spatially correlated samples. These results help
further characterize the scope of exposure to emerging PFAS experienced
by the U.S. population via tap water and augment nationwide targeted-PFAS
monitoring programs.