Harmful ‘forever chemicals’ more prevalent in lower urbanized areas of Delaware River, report finds

A class of “forever chemicals” known as PFAS that have been identified as a health hazard are more commonly found in the lower reaches of the Delaware River where industrial uses are more heavily concentrated, a first-of-its-kind study reveals.

The study, which was released in August, was jointly conducted by the U.S. Geological Survey and the Pennsylvania Department Environmental Protection, and tested the state’s surface waters for polyfluoroalkyl substances, or PFAS.

The U.S. Environmental Protection Agency says PFAS can build up in the environment, people and animals over time. Prolonged exposure to these chemicals has been linked to decreased fertility or increased high blood pressure in pregnant women, developmental effects or delays in children, and increased risk of some cancers, among other health effects, according to the EPA.

The results of the recent study were based on samples of surface water collected in September 2019.

Joseph Duris, an author of the study, explained that, while the samples may have been taken more than four years ago, that extended time was needed to evaluate trends of PFAS concentrations “with a statistically defensible technique.”

PFAS, which have been manufactured since the 1940s, are often found in food packaging, composite wood, non-stick coatings of cookware, and aqueous film forming foams, which are used to fight liquid-based fires.

Urban corridor yields higher results along the Delaware

The study analyzed 33 different forever chemicals in Pennsylvania rivers and streams and found that of the 161 tested, 76 percent contained at least one of the chemicals.

While the data were specific to Pennsylvania, the study’s authors did take samples from tributaries of the Delaware River. Duris said researchers sampled from upstream to downstream and through Pennsylvania.

They started at the West Branch of the Delaware near Hancock, N.Y., to Callicoon and Port Jervis in New York; to Richmond, Pa., and to Trenton, N.J., and Marcus Hook, Pa.

Researchers did not detect any PFAS in the Upper Delaware watershed in upstate New York sites, but as they traveled south, “we saw a steady increase in the concentration of PFAS,” Duris said.

He said the concentration increased as the river heads south and reaches the more heavily industrial and urban sections of Pennsylvania and New Jersey.

The impact of PFAS surfaced in a 2022 water quality report by the Pennsylvania DEP, which flagged fish caught in 536 miles of streams in the Crosswicks-Neshaminy basin as being unfit to be eaten. 

Of the nine basins that make up the Delaware River watershed in Pennsylvania, the Crosswicks-Neshaminy, which includes parts of Bucks and Montgomery Counties, had the most miles labeled in 2022 as being impaired for fish consumption.

All the impaired streams in the Crosswicks-Neshaminy basin in Pennsylvania (the basin also crosses into New Jersey) were considered polluted primarily by PFOS, and in some streams, PCBs, all from unknown sources, the report found. (PFOS are a subgroup of PFAS.)

Wastewater treatment plants can’t keep up

The study identified water pollution control, which treat human waste carrying PFAS, and electronics manufacturing facilities as “primary sources associated with PFAS contamination in surface waters.” 

Wastewater treatment plants, Duris said, are often found in the urban areas where higher PFAS concentrations are recorded. The plants are good at certain things but not great at others, he said.

For instance, they’re good at reducing pathogens in the waste as well as reducing nutrients discharged into the water. But PFAS are trace organic chemicals, which are also found in household cleaners and prescription drugs

Wastewater treatment plants are not “very good at getting rid of some of these trace organic chemicals that are also found in human waste,” Duris said.

Over the past decade or so, there’s been a “renewed focus on wastewater because folks hadn’t really been thinking about them as a source of these chemicals,” he added.

Sara Breitmeyer, a chemist at the U.S. Geological Survey and lead author of the study, said costs may also affect the efficacy of wastewater treatment plants.

“I think it’s more expensive for wastewater treatment plants to use those treatments that they would use for drinking water,” she said, “and that’s a big reason why a lot of the pollutants are going back into the stream without being necessarily filtered out.”

Other monitors

Multiple agencies also monitor PFAS concentrations along the Delaware River.

The Delaware River Basin Commission monitors PFAS concentrations in surface waters, sediment and fish tissue. 

New York created a Water Quality Rapid Response Team in 2016 that addresses water pollution issues by sampling public water and private wells located “around facilities suspected or known to have used PFAS.” 

And the Delaware Department of Natural Resources and Environmental Control maintains a list of sites being investigated for PFAS pollution in drinking water, surface water and groundwater.

The EPA finalized a rule in September that will provide a dataset of PFAS that are manufactured and used nationwide as an effort to combat PFAS pollution.

Duris said that while the Pennsylvania study was not intended to be a part of the EPA’s PFAS Strategic Roadmap, a timeline of specific actions the agency plans to take against PFAS, “we certainly hope that the information that we produce is going to be useful to that process that is underway.”