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  • Writer's pictureEnvironmental Health Project

Profile: John Stolz, PhD

A leader in monitoring the impact of shale gas extraction on private water wells and groundwater in southwestern Pennsylvania

In many of the communities where shale gas development is most prevalent, residents rely on private wells that pump water from an underground aquifer for the household’s water needs. Especially in rural communities, a home’s private water well may be the only source of clean water for basic daily routines.

Hydraulic fracturing requires large volumes of water. Drillers make this water toxic by adding chemicals to produce frack fluid. The water is also contaminated by naturally occurring radioactive materials in the shale that are carried by the frack fluid back to the surface during the process of extracting shale gas. These processes can contaminate water supplies in regions of shale gas development. Water contamination can also occur when wastewater is transported away from the site or stored indefinitely in injection wells.

Contaminated water can result in nosebleeds, skin rashes, and more devastating health impacts, such as respiratory problems. In addition to contamination from chemicals used in shale gas extraction and radioactivity, drilling can cause methane to migrate into the water well, a dangerous condition that can lead to an accumulation of gas that causes the home or well to explode.

Tracking Water Contamination from Shale Gas Development

When seeking data about the impact of shale gas development on groundwater and private well water supplies in western Pennsylvania, residents turn to John Stolz, director of the Center for Environmental Research at Duquesne University in Pittsburgh, and his team of graduate student researchers. Pennsylvania has long been plagued by water contamination. Abandoned mine drainage is reported to have contaminated over 3,000 miles of streams in the Commonwealth making it the most extensive water pollution problem affecting Pennsylvania watersheds. Shale gas drilling has complicated efforts to clean up impacted streams and aquifers. Pennsylvania needs to monitor its water resources diligently to assess how pollution from this new way of extracting gas interacts with damage caused by other industries in the past.

In 2010, Dr. Stolz was involved in a base-line study of two tributaries of Ten Mile Creek in Greene County, PA. It was a collaborative effort involving researchers from the University of Pittsburgh, Carnegie Mellon University, the Carnegie Museum, and Duquesne University. “We wanted to see the water quality and ecology prior to the start of expanded oil and gas exploration,” Dr. Stolz said. He purchased a piece of equipment that could test for compounds indicative of gas brines, mine drainage, or agricultural waste. Armed with this tool and an interest in the role shale gas would play in the region’s continuing struggle for clean water, Dr. Stolz began to receive requests for private water well testing from area residents.

Document on a clipboard describes the Western PA Water Quality Survey program. Contact John F. Stolz, Ph.D. for more information at 412-396-4367

Western Pennsylvania Water Quality Survey

Private water well testing began in 2011, first in Washington County and then in Butler County. Since then, Dr. Stolz has continued to provide free testing of water wells, springs, and streams for residents whether or not they’re living near shale gas development as part of the “Western Pennsylvania Water Quality Survey.” The tests support current research focusing on the fate of oil and gas waste in the Appalachian Basin including Pennsylvania, New York, Ohio, and West Virginia. Samples drawn from well and spring water accessed for household use are tested for salts, such as chloride and bromide, and for metals, including iron, manganese, lithium, barium, and strontium, as well as light hydrocarbons, specifically methane, ethane, ethene, and propane. Residents are asked to complete a survey including questions regarding the water source: type of well and depth, the quality and quantity of the water, and if any changes have been observed.

Jars of brownish water in clear plastic containers with white lids. ID codes written on each container in black marker.
Samples of produced water from an oil well in the Bakken, North Dakota.

Research collected as part of the water quality survey found that the ground and surface water quality of several communities has been impacted by shale gas extraction. Pennsylvania does not regulate the construction of private water wells, so homes may have different well construction and wells at different depths. Neighbors may be affected differently from the drilling operations, as observed when Dr. Stolz surveyed a community in Butler.

Recommendations for Monitoring Private Well Water

In all circumstances, the Pennsylvania Department of Environmental Protection (PA DEP) recommends annual testing of well water. Dr. Stolz has further recommendations for communities with current shale gas infrastructure or where future development is planned.

  • Residents near shale gas development should seek a comprehensive water test, ideally before drilling begins. EHP recommends comprehensive baseline testing and monitoring within three miles of shale gas activities.

  • Residents living very close to shale gas development must also manage testing provided by the driller. Pennsylvania’s Act 13 of 2012 established presumption of liability for water contamination if it occurs within 2,500 feet of a shale gas well and if the contamination occurred within 12 months of the completion, drilling, stimulation, or alteration of the well. Those living at this distance from the wellbore are to be contacted by the drilling company for pre-drill water testing. Dr. Stolz recommends obtaining details about the operator’s testing protocol, including the contaminants that are screened and the sensitivity of the test. PA DEP will compare pre-drill water tests to samples taken after changes are observed when making a determination as to the cause of water contamination.

Surface Water Testing in County Parks

The proliferation of shale gas development in western Pennsylvania has led to the leasing of public lands for resource extraction in Washington and Allegheny Counties. Research conducted by students in Dr. Stolz’s graduate program found evidence to suggest surface water quality has been impacted in Cross Creek County Park and Deer Lakes Park. As new wells are drilled near these parks, it falls to residents to look out for changes in the water’s appearance or adverse impacts to wildlife. In 2017, Dr. Stolz was notified of a fish kill in Cross Creek Park and returned to the park to take additional samples. Continued monitoring of these sites will provide important information for decision makers considering further shale gas leasing of parks and public spaces.

The Prognosis for the Waters of the Commonwealth

“Pennsylvania is blessed with water, lots of it,” says Dr. Stolz. He expects that once a gas well is properly plugged and the source of any fugitive gas or brine sealed off, then the aquifer could recover. But “some contamination is forever.” Particularly concerning is radioactivity. Radium 226 is a gamma emitter with a half-life of 1,600 years. It decays to other radioactive elements including Radon 222, Lead 210, and Polonium 210. Dr. Stolz and researchers have detected Radium 226 in produced water from both conventional and shale gas wells, the leachate from landfills taking oil and gas waste, and discharge from wastewater treatment plants that dispose of the leachate. “The waste is still getting into sources of drinking water,” he says. Bromide, one of the salts in produced water, continues to plague public drinking water facilities, creating trihalomethanes when the water is chlorinated.

Understanding the water chemistry before and after shale gas development is key to protecting the state’s water resources in the future. Dr. Stolz’s lab has analyzed over 1,800 water samples, continuing to provide a critical service to impacted communities with free well water testing. They have also studied samples of produced water from oil and gas wells and products, like de-icers, made from produced water. Dr. Stolz’s analysis of land fill leachate from the Belle Vernon waste treatment plant was critical to understanding the pathways that led to the contamination of a municipal water source. This expansive catalog of research will pave the way for protective regulations and legislation to preserve the waters of the Commonwealth for current and future generations. Until then, communities must remain vigilant to avoid the health harms of using water contaminated by shale gas development.

Visit to learn more about Dr. Stolz's background and research.


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