The Palmerton Zinc Pile Superfund Site in Eastern Pennsylvania was designed to clean up pollution from toxic heavy metals as a result of zinc mining. In that goal, the cleanup has been largely successful. The zinc smelting plant was closed in 1981 and left behind 3000 acres of mountainous terrain contaminated with heavy metals, including cadmium, lead, zinc, arsenic, manganese, and other cancer-causing pollutants. The steep terrain complicated the cleanup. The land was devoid of vegetation, and there was concern about contamination of local water resources. It was acknowledged as a threat to the drinking water of the nearby town of Palmerton, with a population of 5,600.
Miranda Willson of E&E News by Politico wrote about the site in a recent article describing its history and the current concerns.
“With EPA’s blessing, the zinc company spread municipal
sewage sludge as fertilizer on the barren land in the 1990s. A sewage sludge
mixture was used again in the early 2000s, with a total of 112,515 wet tons of
the stuff applied as fertilizer.”
Trees and grasses returned to
the site. Unfortunately, the sewage sludge biosolids contained a hidden
contaminant in the form of polyfluoroalkyl substances, or PFAS, the so-called
“forever chemicals” that have become major emerging contaminants. PFAS are
linked to health issues such as fertility problems, high blood pressure, and
cancer. We now know that concentrated sewage sludge can contain elevated
amounts of these contaminants. This was unknown when the EPA agreed to the
applications. The EPA considers that the biosolids are the likely source of the
chemicals.
“In 2024, the PMA began detecting per- and
polyfluoroalkyl substances (PFAS) including PFOS and PFOA in the groundwater
extracted by the 6th Street Wells. Detections were post combining (mixing) and
post chlorination. The analytical results, which exceed the EPA MCL of 4 ng/L,
are provided below.”
More EPA sampling results
from on-site monitoring wells, the local creek, and from on-site soils are
given below. These include high levels of the most toxic PFAS, which are PFOA
and PFOS. These two were phased out a decade ago.
“EPA collected ground water samples from twelve on-Site
monitoring wells. PFOA was detected in every well at concentrations ranging
from 0.59 to 43 ng/L. PFOS was detected in ten of the twelve well
samples at concentrations ranging from 12 to 76 ng/L.”
“EPA collected surface water samples were collected at
four locations including a background sample. The background sample
was collected from the Aquashicola Creek upstream of the
Site. PFOA and PFOS were detected in the background sample at
2 ng/L and 2.6 ng/L, respectively. A sample from the Aquashicola
Creek immediately across from the Site contained concentrations of PFOA and
PFOS 4.6 ng/L and 6.4 ng/L respectively. On-Site surface water
samples, which are essentially runoff water, contained PFOA concentrations of
37 ng/L and 41 ng/L and PFOS of 100 ng/L and 110 ng/L.”
“EPA collected soil samples were collected from 3
locations on the Site. PFOA was detected in one sample at a
concentration of 5 nanograms per gram (ng/g). PFOS was detected in
all three samples ranging from 2.5 to 13 ng/g.”
These results bring questions
about other Superfund sites and environmental cleanup sites that may have
similarly used biosolids for cleanup as a fertilizer, and the use of them as a
fertilizer in any capacity.
PFAS have been found to be
present in nearly half the nation’s drinking water, though not at the high
levels seen here. They have also been detected in wastewater and sewage sludge.
Willson notes:
“Sewage sludge is increasingly being eyed as a suspected
source in rural areas where it is used as fertilizer, most often on farmland
but also on degraded or contaminated lands.”
“EPA has long promoted the use of sewage sludge
fertilizer. Wastewater treatment plants produce huge amounts of the material,
which must be sent to landfills or incinerated if it isn’t reused. But the
agency has not set regulatory limits for PFAS in sewage sludge.”
It is acknowledged that those
limits should be set for biosolids.
“The Biden administration began to investigate the risk
of PFAS in sewage sludge, releasing a draft report in January that warned that
the material can contain forever chemicals. The Trump administration has not
committed to finalizing the report or pursuing regulations.”
The current EPA is still
reviewing the report after a comment period recently closed.
The original cleanup at the
site used a mix of sewage sludge, fly ash, and limestone as fertilizer. The
goal was two-fold: to aid the growth of vegetation and to prevent the heavy
metals from making it into the groundwater by making them less mobile. EPA was
not aware at the time that biosolids could be contaminated with PFAS. Willson
notes that when it was first discovered:
“3M, a major chemical manufacturer, first warned the
agency that sewage sludge could contain high concentrations of PFAS in 2003,
according to reporting by The New York Times.”
The sewage sludge for the
site came from 16 different wastewater treatment plants in the area. One in
particular in Warminster, Pennsylvania, was home to a former Navy training
center, which used a firefighting foam made of PFAS for decades. That site is
now a PFAS-laden Superfund site, with extremely high concentrations of PFOS
reported in the groundwater.
Another problem with the original Palmerton site cleanup was that in the second application from 2000-2002, the biosolids were applied at more than twice the upper bound recommended in the EPA’s 2025 draft report on sewage sludge risk assessment for PFAS. After 2002, the EPA switched to using compost on the site for fertilization and binding metals.
Below is how sewage sludge biosolids are
disposed of. About half is either landfilled or incinerated. A significant
chunk is used for agriculture and other uses. About 1% of it is used for
remediation.
Below is a conceptual model
of the exposure pathways.
It should be pointed out that
the source of the PFAS in Palmerton’s water has not been definitively
determined. The biosolids, however, are the chief suspect.
“DEP and EPA have not made any determination about the
source of PFAS in Palmerton’s water; however, potential sources are being
investigated,” DEP spokesperson Neil Shader said in an email.
“The maximum level of PFOS detected in the surface water
there is 110 ppt, while the maximum level in the soil was 13,000 ppt, EPA said.
The Centers for Disease Control and Prevention considers PFOS levels in soil
above 52 ppt to be potentially unsafe to adults.”
“EPA said it expects to install a groundwater treatment
system for Palmerton’s drinking water wells by mid-2026, using funds available
through the Superfund program. Due to the difficulty of removing PFAS from
water, such treatment systems can cost millions of dollars.”
“EPA will continue investigating site-related PFAS
contamination to determine any additional sources of PFAS and the extent of the
impacts, which will include testing private drinking water wells for PFAS,
throughout the rest of 2025 and into 2026,” the agency said in its community
notice.
No doubt, the EPA is
reviewing other biosolids applications for remediation as well as for
agriculture. This problem also suggests that all wastewater treatment plants
should test for PFAS. I read recently that mysterious PFAS contamination
somewhere in North Carolina was definitively traced to wastewater from a
textiles manufacturing facility. PFAS contamination issues will likely persist
much like the chemical persists. The problems are solvable will take time and
smart solutions.
References:
EPA:
Superfund cleanup ‘likely’ fouled Pennsylvania town’s water. Miranda Willson.
E&E News by Politico. October 31, 2025. EPA:
Superfund cleanup ‘likely’ fouled Pennsylvania town’s water - E&E News by
POLITICO
Request
for Approval and Funding and Exemption from the $2 Million and 12 Month
Statutory Limit for a Time-Critical Removal Action at the Palmerton Zinc Superfund
Site. U.S. EPA. Region 3. Philadelphia. October 23, 2025. ACTION MEMORANDUM: REQUEST
FOR APPROVAL & FUNDING & EXEMPTION FROM $2 MILLION & 12-MONTH
STATUTORY LIMIT FOR TIME-CRITICAL RE
DRAFT
SEWAGE SLUDGE RISK ASSESSMENT FOR PERFLUOROOCTANOIC ACID (PFOA) CASRN 335-67-1
AND PERFLUOROOCTANE SULFONIC ACID (PFOS) CASRN 1763-23-1. January 2025. U.S.
EPA. Draft
Sewage Sludge Risk Assessment for PFOA and PFOS
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