At least 45 percent of the nation’s tap water is estimated to have one or more types of the chemicals known as per- and polyfluorinated alkyl substances, or PFAS, according to a new study by the U.S. Geological Survey.
There are more than 12,000 types of PFAS, not all of which can be detected with current tests; the USGS study tested for the presence of 32 types.
The USGS research marks the first time anyone has tested and compared PFAS in tap water from both private and government-regulated public water supplies on a broad scale throughout the country. Those data were used to model and estimate PFAS contamination nationwide.
“USGS scientists tested water collected directly from people’s kitchen sinks across the nation, providing the most comprehensive study to date on PFAS in tap water from both private wells and public supplies,” said USGS research hydrologist Kelly Smalling, the study’s lead author. “The study estimates that at least one type of PFAS — of those that were monitored — could be present in nearly half of the tap water in the U.S. Furthermore, PFAS concentrations were similar between public supplies and private wells.”
The U.S. Environmental Protection Agency regulates public water supplies, and homeowners are responsible for the maintenance, testing, and treatment of private water supplies.
The study tested 32 individual PFAS compounds using a method developed by the USGS National Water Quality Laboratory. The most frequently detected compounds in this study were PFBS (perfluorobutane sulfonate), PFHxS (perfluorohexane sulfonate), and PFOA (perfluorooctanoic acid). The interim health advisories released by the EPA in 2022 for PFOS (perfluorooctane sulfonate) and PFOA were exceeded in every sample in which they were detected in this study.
Scientists collected tap water samples from 716 locations representing a range of low, medium, and high human-impacted areas. The low category includes protected lands; medium includes residential and rural areas with no known PFAS sources; and high includes urban areas and locations with reported PFAS sources such as industry or waste sites.
Most of the exposure was observed near urban areas and potential PFAS sources. This included the Great Plains, Great Lakes, Eastern Seaboard, and central/southern California regions.
Click here to access the study.
NGWA has long been an industry leader in providing PFAS research, education, and resources to the public and scientific communities. Learn more by visiting NGWA.org/PFAS, which is a complete resource center about the groundwater contaminants featuring a recently updated top-10 facts sheet, a position paper, and more.
Also found there is Groundwater and PFAS: State of Knowledge and Practice, which NGWA published in 2017 and is one of the first PFAS guidance documents to be released. The Association hosted its second conference last year in Westerville, Ohio, focused entirely on PFAS science and remediation.