The U.S. Environmental Protection Agency (EPA) is launching a new scientific study designed to identify a broad range of known and previously unidentified pollutants that may be present in drinking water.

The research will use non-targeted analysis, an analytical approach that allows scientists to screen samples for thousands of potential contaminants rather than testing only for a predetermined list of chemicals. EPA said the study will examine potential pollutants including pharmaceuticals, per- and polyfluoroalkyl substances (PFAS) and more than 1,000 other contaminants.

Unlike conventional analytical methods, which are designed to measure specific chemicals, non-targeted analysis can help identify unknown compounds present in drinking water samples. EPA said the findings are expected to help inform future research and prioritize potential agency actions.

The study complements EPA's ongoing efforts to identify and evaluate unregulated drinking water contaminants. This spring, the agency released its draft Sixth Contaminant Candidate List, which for the first time identified microplastics and pharmaceuticals as priority contaminant groups. In June, EPA proposed its Sixth Unregulated Contaminant Monitoring Rule, which would require monitoring for 30 unregulated contaminants using existing approved analytical methods.

EPA said the new non-targeted analysis is intended to fill information gaps not addressed through the Contaminant Candidate List and Unregulated Contaminant Monitoring Rule processes.

The agency has not identified specific drinking water systems or locations that will be sampled, nor did the announcement specify which contaminants may ultimately be found through the study.