Fracking’s Threats to Drinking Water Call for a Precautionary Approach

A Marcellus shale gas well operation in Scott Township, Pennsylvania. Photo credit: wcn247/Flickr Creative Commons

At least one aspect of fracking’s risks to drinking water became a little clearer this week.

A study led by Rob Jackson of Duke University’s Nicholas School of the Environment, and published in the Proceedings of the National Academy of Sciences, found that drinking water wells located within 1 kilometer of a shale gas well in a region of northeastern Pennsylvania are at high risk of contamination with methane.

Fracking, shorthand for hydraulic fracturing, is the process of blasting water mixed with sand and chemicals deep underground at high pressure so as to fracture shale rock and release the gas it holds.

Colorless, odorless, and highly flammable, methane is the primary component of natural gas. It is not regulated as a drinking water contaminant, but it poses potential health and safety hazards.  If the gas builds up in a basement or other confined space, for example, it can set off an explosion or start a fire.  If breathed in high enough concentrations, it can cause dizziness, headaches and nausea.

The risks of long-term exposure and of secondary water quality changes due to high levels of dissolved methane are not known.

The research team analyzed 141 drinking water wells in northeastern Pennsylvania’s gas-rich Marcellus shale region and detected methane in 82 percent of them.  For homes within 1 kilometer of a gas well, the average methane concentration was six times higher than in water wells located further away.

Nearly 1 in 11 of the household wells analyzed had methane concentrations above the threshold level set by the U.S. Department of Interior for immediate remediation; all but one of those drinking water wells was within 1 kilometer of an active shale gas well.

By analyzing the isotopic signature of the gases, Jackson’s team determined that the methane found in the drinking water was of fossil origin, not from current biological activity.  The presence of ethane and propane, constituents of natural gas that are not produced by microbes, also signaled that the contamination was coming from nearby fracking operations.

Ethane was detected in 30 percent of the home water wells sampled, and concentrations of this gas were 23 times higher on average for homes less than one kilometer from a fracking well.

“Overall, our data suggest that some homeowners living <1 km from gas wells have drinking water contaminated with stray gases,” Jackson’s team concluded.

Stray gases are those that leak out of the production wells and enter the surrounding environment, including groundwater.  The leaks can occur, for example, from faulty steel casings, which are supposed to keep the gas inside the well. Or they can occur from imperfections in the cement sealing between the well casing and the surrounding rock that permit fluids to migrate up the outside of the gas well.

While compelling, the study is not definitive because of the lack of data on the quality of the drinking water wells before the fracking began.

To better gauge fracking’s risks to drinking water, the natural gas industry should be required to disclose its well records or pay for the state or a third party to collect water quality data before fracking operations are allowed to begin.

Without those data, we are flying blind about where, how and under what conditions fracking poses threats to drinking water.

As the Jackson team concludes: “Ultimately, we need to understand why, in some cases, shale gas extraction contaminates groundwater and how to keep it from happening elsewhere.”

The migration of methane into groundwater is only one possible risk to water quality from fracking.  Another is the potential for the fracking fluids – the toxic mixture of sand, water and chemicals used to break open the gas-holding shale formations – to move through natural or secondary fractures into groundwater.  And yet another is the contamination threat posed by the discharge of toxic wastewater produced by fracking operations.

In all these cases, more scientific research is needed.  Much of it requires that industry not only collect and make available pre-fracking water quality data, but also release the names of the chemicals they are using, instead of hiding them behind the veil of company secrets.

Ultimately, more transparent and safer fracking operations will benefit the industry as well as the families living in fracking territory.  Until the public has full confidence that its drinking water is being safeguarded from contamination, it will continue to protest fracking’s expansion.

If hydraulic fracturing is as safe as its proponents claim, then the industry should welcome the scientific studies needed to prove it so.

Until such studies are completed, the public is wise to call for precautionary measures – including moratoriums on fracking.

Sandra Postel is director of the Global Water Policy Project and Freshwater Fellow of the National Geographic Society. She is co-creator of Change the Course, the national freshwater conservation and restoration campaign being piloted in the Colorado River Basin.

Sandra Postel is director of the Global Water Policy Project and author of Replenish: The Virtuous Cycle of Water and Prosperity. From 2009-2015, she served as Freshwater Fellow of the National Geographic Society. Sandra is also co-creator of Change the Course, the national water stewardship initiative awarded the 2017 US Water Prize for restoring billions of gallons of water to depleted rivers and wetlands. The recipient of several honorary degrees, she works to bridge science, policy, and practice to promote innovative ways of securing water to meet both human and ecosystem needs.
  • Tony

    Long term effects of methane not known? Ever been in a fraternity after a beer and beans night? Our bodies are full of the stuff. Methane is methane, whether biogenic or thermogenic. It is in the atmosphere and part of the air we breathe. It commonly occurs naturally in drinking water.

  • Victoria Switzer

    Precautionary measures would be welcomed here in the gasfields. With 160 wells in my township, I would welcome any type of plan, other than the gas industry plan of drill all drill everywhere…

  • Crystal

    I am a homeowner with well water less than 1500 ft from a drilled well. The drilling company did test our water before drilling started, however, we opted to hire our own independent testing company. We did not have methane in our well pre-drilling. We’ll see what happens when the drilling is done, and in the years to come. If you are on the front lines of this drilling “experiment” know you are on your own. Don’t expect anyone to protect your interests. You must pay for a comprehensive water test BEFORE drilling starts and you must use a reputable company. It’ll run you about $500 in western PA. It is your insurance in case your water turns flammable, or any other number of contamination occurs. Because it does happen, and the industry will say it isn’t their fault, it would have happened anyway, and hey so what if your water lights up? It’s like being in a frat house with the douchebags who light each other’s farts. No danger there. On second thought, I wonder if the industry will start suing the homeowners for the methane in their water? After all, it was extracted due to the efforts and investments of the drillers.

    • Crystal, thank you for sharing your personal experience and advice. – Sandra

  • Philip

    The contamination from drilling is “not an epidemic. It’s a minority of cases,” said Rob Jackson, a Duke University researcher and co-author of the study…We’re not seeing the things that people are most afraid of,” Jackson said, referring to the chemicals used in fracking. Amazing what selectively editing the data will do for your argument. Another scare monger. Sandra probably screams “settled science” whenever global warming is mentioned as well.

    • Of course it’s a minority of cases. So is cancer, so are car accidents, so are lot of things we try to prevent because they cause harm to our fellow citizens. The point is to ensure that the environmental and social costs of fracking are internalized into gas production rather than externalized onto communities and society-at-large. And for the record, I rarely scream.

  • Thomas

    With every passing month, more and more information comes out about the harmful impacts of fracking. Just in the past few years, we’ve seen extreme benzene contamination in Parachute CO, flammable water in Pavillion WY (and Weld County CO, and Northeastern PA), and billions of gallons of local water supplies going to waste in drought prone areas in the southwest. Despite all of this, the industry continues to assert that there never has been, and never will be, negative impacts from fracking. The time has come for our lawmakers to wake up. Natural gas is NOT a “bridge fuel” that will “ease the transition to clean energy”. It is a massive waste of clean water, a threat to public health, and is in reality worsening climate change for future generations.

  • Lori Gilliam

    Hello people wake up ! Greed for money with the cost of killing yourself and our inviroment !!!!!! FRACKING KILLS !!!!

  • Celia Janosik

    Methane is everywhere but breathing in large amounts of methane over a period of time seems to me to be unhealthy. I correspond with someone who believes she has been poisoned by methane and she suffers great pain in her joints along with swelling over large parts of her body, terrible blisters on her skin and has a difficult time functioning. I believe this industry knows exactly what effects slick water hydraulic fracturing along with other forms of drilling does to the human condition. The fossil fuel empire does not care nor does all levels of our government, we are collateral damage.

  • Tony


    Terrible that your correspondent suffers so. Iam sorry for her. However, what evidence it is caused by methane? Methane From where? Concentration? What eVidence? Anecdotal or verified by a medical specialist? I guess all the published toxicological data on methane is not relevant to you.

    Your beliefs do not make a thing true…as the saying goes… You are entitled to your opinion. You are not entitled to your own truth.

  • Brian

    What is polluting these family’s water wells is not pure methane (such as found in refined natural gas), but raw shale gas. Jackson’s PNAS paper documents minor amounts of ethane and propane, and typically there are trace amounts of a host of nasty petrochemicals.

  • Tony, while it’s true methane occurs naturally in the air, what is more problematic is a high concentration in one spot, such as may be found near a leaking well. Methane in the atmosphere as a whole is quite dilute, but that may not be the case in local areas, especially enclosed ones.

  • Garry

    The Vanadanamu Ethical Cottons Go Solar, Go Sewing Startsomegood crowd funding campaign is so inspiring.
    To be able to help the people of this community in India leapfrog to a high tech clean renewable energy future and bypass the destructive path we have been on is a win win for us all.
    We live in one of the wealthiest countries in the world and yet our government is allowing coal mining companies to unnecessarily damage our environment.
    Coal mines are trying to divert waterways and leave behind huge voids that are hazardous to communities, wildlife and groundwater because poisonous salts and heavy metals build-up in the water. The voids and spoil heaps are also a loss to farming and grazing land for future generations.
    And in the United States where they are required to fill in and rehabilitate voids, the government fast tracked coal seam gas fracking with exemptions from the Clean Air and Clean Water Acts because of fear about lack of energy independence.
    Now Australia is being pressured to approve high risk coal seam gas projects without adequate baseline studies when they only give marginal benefit over coal and may be even worse for global warming and water quality.
    The fossil fuel industry impacts from the ports, dredging the sea bed, shipping and polluting waterways are even threating the Great Barrier Reef that has already lost more than 50% of its coral cover and is predicted to lose another 50% over the next decade unless we change course.
    When you consider that enough sun falls on the earth in an hour to power the whole world’s energy needs for a year, they should have looked up rather than down as the vulnerable fabric of our lands are what we depend on for life.
    Please have a look at this really well put together campaign site.

  • Alyce

    This is the full study. The citation above is only a small part, and this article makes it seem as if the study is somehow inconclusive. It isn’t. The best argument to make isn’t even about the poisoned drinking wells, but about the use of fresh water, millions of gallons per well head lost completely, never to return to the water table.

  • Deborah K

    Good post. Yes, a moratorium for all of Pennsylvania, not just the Delaware River Watershed, is needed now!

    Pennsylvania Constitution, Article 1, Section 27:
    The people have a right to clean air, pure water, and to the preservation of the natural, scenic, historic and aesthetic values of the environment. Pennsylvania’s public natural resources are the common property of all the people, including generations yet to come. As trustee of these resources, the Commonwealth shall conserve and maintain them for the benefit of all the people.”

  • Macdonald

    Nice comments. The truth about the matter is that no human activity is risk and accident free. The key question we need to answer is that; are the health and environmental risks associated with gas fracking beyond the acceptable threshold? If yes, then, what is expected is a higher dimension of precautionary measures where policy should be directed toward making sure the externalities are internalized even before they occur by the industry. By this the shale gas industry should be cajoled to result to improving other forms of hydraulic fracturing techniques which have less health and environmental implications rather promoting a cheaper form technique with diverse demerits to humans and environments.

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