USGS Estimates PFAS in Groundwater Risks 70 Million

According to a recent U.S. Geological Survey (USGS) report, over 70 million people across the contiguous United States may be consuming water from sources contaminated by PFAS chemicals, a group of synthetic compounds linked to health risks. This analysis is the first national estimate of PFAS presence in untreated groundwater supplying both public and private drinking wells, emphasizing widespread exposure risks.

The findings provide critical insights into the prevalence of PFAS, or “forever chemicals,” in U.S. groundwater and can help public health officials, water suppliers, and individuals make informed decisions regarding water quality. The research also includes a predictive model and interactive map, offering a detailed look at regional and state-level PFAS probability in groundwater sources.

PFAS and Health Concerns

PFAS (per- and polyfluoroalkyl substances) are synthetic chemicals with uses ranging from non-stick cookware and food packaging to firefighting foams. Known for their resilience, these compounds are resistant to breakdown, often persisting in the environment and accumulating over time, hence their “forever chemicals” nickname. Studies have linked PFAS exposure to potential health risks, leading the U.S. Environmental Protection Agency (EPA) to establish maximum contaminant levels (MCLs) for six PFAS types in public water systems. However, there are no MCLs for private wells, placing the responsibility of testing and treatment on individual households.

Impact of PFAS on Public and Private Wells

The USGS report suggests that around 20% of Americans may rely on groundwater with detectable PFAS levels for drinking water. While the EPA regulates public water supplies, individual well owners often lack the resources and knowledge to test and treat their water independently. Andrea Tokranov, a USGS research hydrologist and lead author of the study, highlights this gap: “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.”

USGS Findings and Model Insights

Using over 1,200 groundwater samples, USGS scientists analyzed factors like urban development and well depth to build a machine-learning model that estimates PFAS presence across regions. The research focused on 24 common PFAS types, with perfluorobutane sulfonate (PFBS), perfluorooctane sulfonate (PFOS), and perfluorooctanoate (PFOA) appearing most frequently in the samples. The model does not predict specific concentrations or identify all PFAS types, as over 12,000 varieties exist, many of which remain undetectable by current tests.

For public wells, which generally access deeper groundwater, the estimates reflect broader contamination trends compared to shallower private wells, often closer to surface pollutants. These model estimates are accessible through an interactive USGS map but are meant for analysis at broader levels rather than for individual households, as they do not consider local treatment or filtration efforts.

State-Level PFAS Risks

State-level analysis revealed notable regional variation in PFAS risk for both public and private well users. In states like Massachusetts, 86% to 98% of the population relying on public groundwater sources may be exposed to PFAS. Similarly, 67% to 87% of Connecticut residents depending on private wells may face PFAS exposure.

Larger states like California and Florida, with significant populations using public groundwater sources, show high potential contamination rates. Michigan, North Carolina, Pennsylvania, New York, and Ohio also face considerable risk among private well users.

Regulatory and Personal Actions on PFAS

The EPA has taken steps to regulate PFAS levels in public water systems, but private well owners need to stay informed and proactive about potential contamination. Individuals using private wells can access EPA resources for guidance on testing and treatment or reach out to local water authorities for support. Testing remains the only reliable method to confirm PFAS presence in drinking water, as the predictive model offers estimates rather than concrete measurements.

Persistent Contamination and Future Steps

This study underscores the need for expanded PFAS monitoring, particularly in private water supplies. With an interactive map and state-by-state breakdowns, the USGS model empowers local and regional authorities to identify areas with heightened contamination risk, aiding in strategic water resource planning. For individual households, installing reverse osmosis systems or whole-home water conditioners can be effective in reducing PFAS and other contaminants, helping ensure cleaner, safer water.

As scientific understanding of PFAS advances, the USGS study provides an essential tool in assessing groundwater quality across the United States. While predictive models and regulations play a role, the responsibility for PFAS detection and treatment often falls on individuals, especially private well users.

Source: Sci Tech Daily