Up to Two-Thirds of US Groundwater Supply May Contain PFAS

By: Sierra Club

Nov 4, 2024

Nearly 95 million people in the United States may be relying on groundwater contaminated with human-made “forever chemicals,” according to a groundbreaking study released by the U.S. Geological Survey (USGS). Known as PFAS, these synthetic chemicals are found in everyday items like fabric softeners, waterproof clothing, and nonstick cookware. Over time, they have seeped into groundwater supplies, posing significant health risks. Linked to serious conditions such as kidney and testicular cancers, thyroid disease, and fertility issues, PFAS are highly toxic to human health.

While PFAS contamination in drinking water has been recognized for years, the USGS study provides the first national estimates of their presence in groundwater. Researchers analyzed data from more than 1,200 groundwater samples across the country and developed a predictive model. By incorporating variables like population density and well depth, the model estimates the likelihood of PFAS contamination in areas where direct samples haven't been taken.

The study concluded that between 50% and 66% of the 145 million Americans relying on groundwater may be ingesting PFAS daily. Urban land use emerged as the strongest predictor of contamination, according to lead author Andrea Tokranov. Highly urbanized areas such as Florida, Southern California, and states along the Eastern Seaboard showed the highest likelihood of contamination. In particular, over 80% of private wells in Connecticut, Rhode Island, and New Jersey, as well as up to 98% of the public water supply in Massachusetts, were predicted to be contaminated with PFAS.

Probability of PFAS occurrence in groundwater. Credit: Science (2024).DOI:10.1126/science.ado6638

For more details, see the original article, the interactive map, and the published study.