The degradation of U.S. drinking water supplies by hazardous per- and polyfluorinated alkyl substances (PFAS) is extensive, according to recent research conducted by the U.S. Geological Survey (USGS).

At least 45% of the nation’s tap water is estimated to have one or more types of these forever chemicals.A gloved researcher collects a tap water sample from a kitchen sink using small plastic vials to test for PFAS. Source: USGSA gloved researcher collects a tap water sample from a kitchen sink using small plastic vials to test for PFAS. Source: USGS The analysis of tap water from 716 locations (269 private-wells; 447 public supply) revealed the presence of one to nine individual PFAS types with corresponding cumulative concentrations ranging from 0.348 ng/l to 346 ng/l. Most PFAS exposure was found near urban areas and potential chemical sources, with higher counts in the Great Plains, Great Lakes, Eastern Seaboard and Central/Southern/California regions.

For several compounds, including perfluorooctanoic acid and perfluorobutanoic acid, concentrations decreased with increasing development, an unexpected result that suggests that point-of-use tap water exposure to individual PFAS is more closely associated with the type of PFAS sources, such as airports or industrial facilities generally located at the edge of urban development and not in the highest residentially developed areas.

Data reported in Environment International indicate that at least one PFAS was detected in 20% of private-well and 40% of the public-supply samples collected throughout the U.S.

An interactive map developed by the nonprofit Environmental Working Group pinpoints where these chemicals have been detected above and below the advised maximum concentration level of 4 ppt in public drinking water systems.

To contact the author of this article, email shimmelstein@globalspec.com