Population-Wide Exposure to Per- and Polyfluoroalkyl Substances from Drinking Water in the United States

The
extent of ongoing exposure to the general public from per-
and polyfluoroalkyl substances (PFAS) in drinking water in the United
States and worldwide remains uncertain. Here, we analyze publicly
accessible data sets of PFAS occurrence in drinking water in the United
States. Testing with detection limits below 1 ng/L revealed that mixtures
of PFAS are nearly ubiquitous in surface water, the predominate source
of drinking water for the U.S. population. We estimate that 18–80
million people in the U.S. receive tap water with 10 ng/L or greater
concentration of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate
(PFOS) combined, and over 200 million people likely receive water
with a PFOA and PFOS concentration at or above 1 ng/L. Multiple U.S.
states including California, Massachusetts, Michigan, New Hampshire,
New Jersey, New York, and Vermont have either set or proposed limits
for PFOA and PFOS that are significantly lower than the nonregulatory
U.S. Environmental Protection Agency established lifetime drinking
water health advisory level of 70 ng/L for the combined concentration
of PFOA and PFOS. There is significant variation in PFAS occurrence
within and between different U.S. states, highlighting the need for
systematic monitoring of PFAS in both source and finished drinking
water.