‘Forever chemicals’ found in 76% of Pennsylvania streams sampled

Pennsylvania is known by anglers and outdoor enthusiasts for its thousands of miles of streams and rivers that lace the rugged Allegheny Mountains, rolling farmlands, and cities such as Pittsburgh and Philadelphia. Many of those waterways supply drinking water for millions.

But a study by the U.S. Geological Survey found that many of those waterways are also tainted by so-called forever chemicals. The USGS sampled streams across Pennsylvania and found that 76% of them contained the presence of at least one compound from the per- and polyfluoroalkyl substances (PFAS) family, according the first study of its kind looking at the problem across a single state and associating possible sources.

PFAS are a group of 12,000 man-made chemicals that have been used widely to make a range of products such as nonstick cookware, stain-resistant furniture, the linings of fast-food boxes, and firefighting foam.

High concentrations can lead to adverse health risks in people, according to the U.S. Environmental Protection Agency. The USGS says that the chemicals’ persistence in the environment and prevalence make them a top concern for water quality. Some health effects associated with PFAS include decreased fertility, testicular and kidney cancers, high cholesterol, autoimmune and thyroid problems, alterations in hormone functioning, and developmental effects.

The two highest concentrations of per- and polyfluoroalkyl substances (PFAS) were found in the Philadelphia region: Neshaminy Creek in Bucks County and Valley Creek in Chester County.

The study did not include sampling of drinking water, only raw, untreated surface water. But the authors say their findings suggest the need for updated water treatments to remove PFAS contaminants in systems that draw from waterways.

Scientists with the USGS first set out in 2019 to sample 161 waterways to find potential sources of PFAS contamination from 33 different compounds within that family, nicknamed “forever chemicals” because of their persistence of remaining intact in the environment and human body. Results of the study, conducted in partnership with the Pennsylvania Department of Environmental Protection, were published recently in the journal Science of the Total Environment.

The DEP has also previously found PFAS in waterways. It has issued an advisory warning that anglers not eat fish caught in Neshaminy Creek.

Officials say the new study can be used by federal, state and local agencies working to reduce exposure of the compounds to the public and wildlife.

“This is the first statewide study that associates electronics manufacturing as a source of PFAS in streams, which is likely an under recognized, but significant, source of PFAS contamination,” said Sara Breitmeyer, a USGS chemist and lead author of the study. “I was surprised to see that the highest levels of PFAS in our study streams were associated with electronics manufacturing because that’s not as well known of a source.”

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two of the most widely used and studied chemicals in the PFAS group. But they have been replaced with other PFAS compounds in recent years.

There are no federal standards set for PFAS in surface waters, such as streams and rivers.

But this year, the U.S. Environmental Protection Agency proposed the first ever national drinking water maximum contaminant levels (MCLs) for PFOA and PFOS concentrations and set the level to near zero. Both Pennsylvania and New Jersey have their own standards.

Pennsylvania’s maximum levels for drinking water are 14 parts per trillion (ppt) for PFOA and 18 for PFOS. If the EPA rule is adopted, it would supersede state laws.

The USGS study used the DEP’s existing network of water sampling sites. It looked for 33 types of PFAS from water collected from streams from the Ohio Valley to Southeastern Pennsylvania.

Local waterways that exceeded the proposed levels include the Schuylkill in Pottstown and at Falls Bridge in Philadelphia; Perkiomen Creek near Collegeville; Brandywine Creek at Chadds Ford; Wissahickon Creek at its mouth in Philadelphia and at Fort Washington; Red Clay Creek near Kennett Square; Neshaminy Creek near Langhorne, and Valley Creek near Valley Forge.

Philadelphia draws its drinking water from its two rivers, the Schuylkill and the Delaware. The Philadelphia Water Department monitors for PFAS but does not have filtration specifically designed to remove it. However, the PWD says that PFAS levels have been found “well below” allowable levels set by Pennsylvania. However, testing also showed levels above the new proposed federal rule and PWD says it is evaluating new treatment methods.

Other water departments are starting to install special filtration systems to handle the problem.

Breitmeyer stressed that her study did not sample PFAS in drinking water, and made no conclusion about its quality.

The waterways tested across the state are protected from pollution under state law if they are used for drinking water. Of the 161 tested, 16 exceeded the new EPA proposed maximum contaminant level of 4 ppt for PFOA. And 11 exceeded the proposed level of 4 ppt for PFOS, according to the study.

“The potential insufficient removal of PFOA and/or PFOS during conventional drinking water treatment techniques” could expose millions of residents to concentrations that exceed the EPA’s proposed standards, the report states.

The USGS sampled the streams between Sept. 3 and Sept. 26, 2019, and meshed the data with legal discharges from manufacturing facilities. It also included data for land use.

The median concentration of PFAS, meaning half were lower and half were higher, was 3.8 parts per trillion (ppt). Concentrations ranged from nondetectable to 102 ppt at Neshaminy Creek near Langhorne.

Maximum concentrations occurred in areas that had potential sources of contamination ranging from military bases, water pollution control facilities, electronics manufacturers, and petroleum operations.

Only two streams exceeded the EPA’s newly proposed EPA Hazard Index: the 11-mile long Valley Creek and the 41-mile long Neshaminy Creek. The Hazard Index accounts for a larger range of PFAS beyond just PFOA and PFOS that may be found in contaminated drinking water.

The study said that wastewater from an electronics manufacturer “may have been a prevalent PFAS source at Valley Creek.”

PFAS contamination in Neshaminy Creek has been associated with firefighting foam used at a former joint military base in Horsham, according to a former study.

Commercial and housing development also appears to be correlated with higher PFAS levels. Waterways downstream from highly developed areas tended to have higher PFAS levels — particularly if an electronics manufacturing facility was part of that development. The authors note electronics manufacturing requires processes that use chemical mixtures containing various PFAS.

In rural areas, however, agriculture was associated with higher PFAS concentrations because waterways catch runoff from farmland. PFAS has been associated with the application of contaminated biosolids and recycled irrigation water on farms.

Streams near small rural towns surrounded by high oil and gas development were found to contain low levels of PFAS contamination.

Breitmeyer said no one should panic about drinking water.

“We did not study treated drinking water levels, but this finding does indicate the need for effective water treatment techniques that will remove PFAS contaminants in drinking water sourced from raw stream surface waters,” she said.

This article has been updated to reflect that while Philadelphia Water Department testing has shown PFAS levels well under state maximum allowable levels, some of those levels are above a proposed federal rule and that PWD is evaluating new treatment methods.