A study by the Pennsylvania Department of Environmental Protection found that the liquid runoff, or leachate, from Pennsylvania landfills that receive solid oil and gas waste poses no “significant” threat to the public from radioactive materials found in that waste. The DEP sampled leachate at 49 landfills. The results indicate that most were below federal drinking water guidelines of 5 picocuries per liter, and that none of the results were over a much higher standard of 600 pCi/L established by the Nuclear Regulatory Commission for wastewater sent to treatment plants from facilities like nuclear power plants.
DEP notes:
“DEP did not identify any levels of radiation
associated with the landfill radium leachate investigation that raised concern
for environmental protection or public health and safety. No results were
observed that would require landfill action or suggest changes to engineering
or operational controls.”
I would say that this result
was expected. Over a decade ago, I attended a talk by West Virginia water
resources expert Paul Ziemkiewicz that explored research he and his students
had done to characterize the leachate from landfilled oil and gas waste,
including drill cuttings. He concluded that the risk was small for pollutants,
although they did not go into detail about radioactivity. Previous studies of
releasing untreated oil and gas wastewater into rivers, which was done for the
first few years of Pennsylvania’s shale gas revolution until 2011, when the
practice was stopped. Those studies did find that radium increased in those
downstream waters and sediments after the wastewater was released.
According to an article by
the environmental group Allegheny Front, some other scientists who study
radioactivity were underwhelmed. A previous study, published in 2023 in the
journal Ecological Indicators, found that radium levels in sediment downstream
municipal water treatment plants receiving such leachate were two to four times
the background level of radium upstream of the plants. Those researchers
believe that radium levels can accumulate and increase over time and become
more toxic. A 2016 DEP study also found that the risks from radioactivity were
not significant for workers or nearby residents. However, in 2021, they did
recommend further study of landfill leachates. Tracy Pawelski, a spokesperson
for the Pennsylvania Waste Industries Association, which represents the state’s
landfills, noted in 2023:
“Pennsylvania landfills have long been equipped with
sophisticated radiation detection equipment that monitors every load of waste
entering the facility,” Pawelski said. “Any load with unacceptable radiation
levels, regardless of its source, are managed pursuant to radiation waste
management plans approved by the DEP.”
Nathaniel Warner, associate
professor in civil and environmental engineering at Penn State, criticized the
current study as inadequate due to how radium levels were calculated and where
samples were collected.
“The state didn’t collect, or didn’t appear to collect,
a single sample of the water actually leaving either the sewage treatment
plants or the leachate treatment plants of the facilities,” he said. “To
conclude that there’s no risk seemed like a stretch because they didn’t test
the sediment or the water at the discharge.”
The Marcellus Shale, source
of most of the oil & gas waste, contains higher than usual amounts of
radioactive material due to the shale’s uranium and thorium content, which
decays into radium. The current DEP study included two ways to measure radium
levels. The first way, which is less precise but also less expensive, yielded
higher radium levels between 308 and 540 picocuries per liter. The second
method, more precise but also more expensive, yielded much lower radium levels
of between 1.43 and 122.731 picocuries per liter.
“In the more accurate radiochemistry test, only 11
landfills had radium levels above the federal drinking water guidelines of 5
picocuries per liter. And of those 11, only four landfills had “reportedly”
accepted oil and gas waste between 2015 and 2024.”
“DEP found no correlation between radium levels above 5
pCi/L and the acceptance of oil and gas waste at the landfill,” the report said.
Thus, as can be seen, some of the landfills sampled that had radium levels above 5pCi/L did not even accept oil & gas waste. This shows that there are likely other sources of radium. One might be runoff from exposed shale outcrops, but I am just speculating here.
The DEP noted that results
were similar to its 2016 TENORM study. The report explained landfill leachate
containment and treatment in the state:
“Landfills are designed with a leachate collection
system to ensure leachate does not enter the groundwater and is collected for
treatment. Collected leachate must be subsequently treated by a permitted
wastewater treatment operation. Upon meeting National Pollutant
Discharge Elimination System (NPDES) water quality standards, the treated
leachate may be discharged to a receiving body of water. Some landfills operate
onsite treatment systems while others are connected to local publicly owned treatment
works (POTWs), which treat landfill leachate prior to discharge. Because
landfills accept oil and gas industry wastes, such as drill cuttings and
treatment sludge that may contain TENORM, there is a potential for leachate
from those facilities to also contain TENORM.”
The radiochemistry results,
more accurate than the gamma spectroscopy results, were also much lower, with
few exceeding drinking water limits, which, after further dilution in the
environment, would drop considerably before affecting drinking water supplies,
if at all. As noted in the study’s conclusions below, the DEP recommends a year
of further study of these landfills to collect more radiochemistry samples. The
bottom line is that radioactivity from the most radioactive organic shales,
such as the Marcellus, is not likely to be of concern to the environment or
public health, but it should still be monitored.
References:
PA DEP
says ‘no risk’ to the public from radioactive materials in oil and gas waste
sent to landfills. Reid Frazier. The Allegheny Front. March 20, 2026. PA
DEP says ‘no risk’ from radioactive materials in fracking waste sent to
landfills - The Allegheny Front
DEP
Study Shows No Radiation Risk from Leachate in Pennsylvania's Landfills.
Pennsylvania DEP. March 13, 2026. DEP
Study Shows No Radiation Risk from Leachate in Pennsylvania's Landfills |
Department of Environmental Protection | Commonwealth of Pennsylvania
Landfill
Leachate Study. Pennsylvania DEP. Landfill
Leachate Study | Department of Environmental Protection | Commonwealth of
Pennsylvania
RADIUM
IN UNTREATED LANDFILL LEACHATE INVESTIGATION. Pennsylvania Department of
Environmental Protection. January 2026. PA
DEP Final Radium Leachate Report.pdf
Study
finds radioactive materials in waterways near treatment plants associated with
fracking waste. Reid Frazier. The Allegheny Front. July 20, 2023. Study
finds radioactive materials in waterways near treatment plants associated with
fracking waste
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