PFAS Found In Untreated Well Water Across Del., Says USGS


Contaminants known as PFAS have been found to be widely distributed in untreated well water in Delaware, with the highest number of types of chemicals in Sussex and New Castle Counties.

The wells receive their groundwater from the Columbia aquifer, and samples found to contain the chemicals generally had low concentrations. Research is still going on to better understand the potential health effects of PFAS exposure over long periods of time, especially in children.

“This is a sampling in well water prior to being treated. It is representative of the ground water and not necessarily drinking water, US Geological Survey scientist and author of the study Betzaida Reyes said.

The chemicals have been used for decades for a wide variety of purposes, and are sometimes called forever chemicals because they do not break down very quickly.

“Even though use of some PFAS have been banned, we found that the chemicals are still present in the environment,” Reyes added. “The Columbia aquifer is an important drinking water source for hundreds of thousands of people, and our research will help decision-makers and communities understand how PFAS are impacting the quality of some area groundwater.”

According to the US Geological Survey:

The four most frequently detected PFAS in this study were PFOA; perfluorohexanoic acid, known PFHxA; PFOS; and perfluorohexane sulfonate, known as PFHxS.

PFAS were used starting in the 1940s and although some have since been prohibited, they are a continued concern because they are long-lasting and have been widely used across the country. Sometimes called “forever chemicals,” PFAS are not readily biodegradable and break down very slowly, and because of that can build up in people, animals and the environment over time.

The USGS conducted the study in cooperation with the Delaware Department of Natural Resources and Delaware Geological Survey.

“This USGS study is the first of its kind for Delaware, providing a comprehensive, baseline understanding of which PFAS are present and at what concentrations in well water throughout most of the state,” Reyes said. “We could not have done this work without the support of our partners and the property owners and water managers who gave us access to their property so we could sample wells.”

To read the USGS report, please CLICK HERE

Click for the EPA’s PFAS website 

Click for Delaware’s PFAS information page

Click for USGS PFAS study strategy