Approximately 71 to 95 million people in the Lower 48 states — more than 20 percent of the country’s population — may rely on groundwater that contains detectable concentrations of per- and polyfluoroalkyl substances (PFAS) for their drinking water supplies, according to a
U.S Geological Survey study published October 24.
Along with a scientific report, the USGS published an
interactive, online map so users can see probability estimates of PFAS occurrence. Note that predictive results are intended to be evaluated at state, regional and national scales rather than at individual household levels. Probability estimates are for the presence of PFAS in groundwater and do not account for any subsequent actions taken by states, municipalities or individuals to treat drinking water. The model does not include estimates of PFAS concentrations; testing is the only way to confirm the presence of contaminants.
“This study’s findings indicate widespread PFAS contamination in groundwater that is used for public and private drinking water supplies in the U.S.,” said Andrea Tokranov, USGS research hydrologist and lead author of this study.
“This new predictive model can help prioritize areas for future sampling to help ensure people aren’t unknowingly drinking contaminated water. This is especially important for private well users, who may not have information on water quality in their region and may not have the same access to testing and treatment that public water suppliers do.”
The states with the largest populations relying on public water supplies with potentially contaminated groundwater sources are Florida and California. Regarding private wells, Michigan, Florida, North Carolina, Pennsylvania, New York and Ohio have the largest populations relying on potentially contaminated groundwater.
The study also presents data according to population percentage. In Massachusetts, for example, the source water for 86 to 98 percent of people who rely on groundwater from public water supplies could be contaminated with PFAS. In Connecticut, the source water for 67 to 87 percent of the people who rely on groundwater from private wells could be affected. Details by state can be seen in the report’s tables S6 through S8.
Click here to see the report's table and read more.