Unseen PFAS Contamination: A Hidden Threat to North Carolina's Water Supply
A recent Duke University study has uncovered a hidden threat to the water supply in North Carolina: a previously undetectable form of PFAS pollution that has been contaminating drinking water for years. The study reveals how tiny PFAS 'nanoparticle' precursors, released by a textile manufacturer, have been transforming into more toxic chemicals and contaminating water in communities downstream, including Chapel Hill and Pittsboro.
The researchers, led by environmental engineering professor Lee Ferguson, first noticed something was wrong when PFAS levels in the Haw River downstream were far higher than anything showing up in Burlington's wastewater monitoring. The problem was traced to the textile manufacturer's release of these unusual particles, which slipped past standard testing methods.
To solve the mystery, the researchers used a chemical process to convert everything in the wastewater into measurable PFAS. Concentrations then jumped, revealing a class of PFAS that had never been detected in the environment before. These nanoparticulate PFAS behave more like tiny solids than dissolved chemicals, making them invisible to mass spectrometers commonly used in PFAS testing.
The findings help explain earlier red flags. Haw Riverkeeper Emily Sutton said her organization documented extreme contamination years before scientists understood its source. The problem was also partly due to Burlington's former sludge-reduction system, which created ideal conditions for PFAS precursors to convert into more toxic PFAS molecules.
Once the textile manufacturer changed its industrial practices and Burlington discontinued the problematic treatment method, PFAS levels dropped significantly. The study underscores a central challenge for regulators across the country: just measuring for the standard set of PFAS on regulatory lists is not protective in every situation. We need to understand and regulate PFAS precursors that might not be on anybody's list right now.
The discovery also points to long-term risks. Before the changes, PFAS precursor nanoparticles were concentrated into biosolids that were spread on agricultural fields for years. These particles will continue breaking down slowly, releasing PFAS into waterways and agricultural settings for years to come.
The study offers a playbook for other communities to collaborate with researchers, regulators, and industry to decrease PFAS at the source. However, it also highlights the need for better methods and a broader scope of analyses to find these hidden sources.
