BETHLEHEM, Pa. — New research has found widespread and persistent PFAS contamination throughout the Delaware River system, with evidence pollution sources are continuing to feed so-called “forever chemicals” into the watershed.
The study, released late last week by Delaware River Basin Commission, detected per- and polyfluoroalkyl substances in surface water, sediment, fish and blue crab tissue collected throughout the basin, including along the tidal Delaware River.
“This implies PFAS compounds are being released into this section of the river faster than they are being diluted, likely due to point and nonpoint PFAS sources."Delaware River Basin Commission report
Researchers found PFAS concentrations generally increased as water moved downstream toward Delaware Bay — even as river volume expanded — suggesting new contamination is entering the river faster than it is being diluted.
“This implies PFAS compounds are being released into this section of the river faster than they are being diluted, likely due to point and nonpoint PFAS sources,” the report states.
The findings are part of the commission’s three-year PFAS Water Quality and Fish Tissue Assessment Study, which builds on decades of research of continued PFAS monitoring across the basin.
PFAS, known as "forever chemicals" because they break down extremely slowly in the environment, are used in products as diverse as nonstick cookware, waterproof fabrics, firefighting foams and industrial manufacturing.
Fish contamination raises additional concerns
The study found PFAS contamination in several fish species commonly caught throughout the watershed, including white perch, channel catfish, white sucker and smallmouth bass.
Researchers found PFOS — one of the best-known and most studied PFAS compounds — in every fish sample analyzed.
Some smallmouth bass samples collected from the non-tidal river exceeded chronic PFOS exposure thresholds tied to fish consumption guidance, according to the report.
White perch collected from tidal portions of the river also showed elevated PFAS accumulation.
"The Delaware River Basin is a global hotspot for PFAS pollution and this study adds more data showing that these chemicals are widely present in water, fish, crabs and sediment."Jeremy Conkle, DRBC
Researchers cautioned that fish migration patterns make it difficult to pinpoint precise contamination sources based solely on tissue samples, but said the findings demonstrate how PFAS compounds are moving through the broader river ecosystem.
“The Delaware River Basin is a global hotspot for PFAS pollution and this study adds more data showing that these chemicals are widely present in water, fish, crabs and sediment," Jeremy Conkle, DRBC senior chemist/toxicologist and lead author of the study, said in a release.
"Demonstrating that we are in the early stages of what will be a long-term effort to reduce their loading and protect ecosystem, organismal and human health.”
Evidence points to lower river pollution corridor
While the study documented contamination throughout the basin, researchers identified the lower tidal Delaware River — particularly areas south of Chester, Chester County — as a likely zone of continuing PFAS inputs.
The report notes the river stretch includes numerous industrial facilities, wastewater treatment plants, urban stormwater systems and the Christina River near Wilmington, Delaware, which researchers described as a known PFAS hotspot.
Researchers also documented unusually elevated PFAS levels near a stormwater outfall adjacent to Philadelphia International Airport and its firefighting training facilities, though the report said the findings were inconclusive regarding the exact source.
"Safeguarding water for over 14 million people requires science-informed management actions."Kristen Bowman Kavanagh, DRBC executive director
“Safeguarding water for over 14 million people requires science-informed management actions,” DRBC Executive Director Kristen Bowman Kavanagh said in the release.
“We will continue our decades-long active monitoring of PFAS and heighten our focus on targeted tracking, trend modeling and data communication.”
New interactive map launches soon
The commission said it will launch a new interactive online mapping tool, PFAS in the Delaware River Basin, during a public webinar scheduled for noon June 15.
Members of the public can register for the webinar here.
The tool combines PFAS data from federal, state and regional agencies into a public map that lets users explore contamination data throughout the watershed, including local tributaries.
Officials said continued monitoring will be critical to identifying contamination trends, improving source tracking and guiding future regulatory and cleanup efforts across the basin.
