Water samples in Pennsylvania suggest there may be natural pathways for contamination.

Drinking water contamination from horizontal drilling and hydraulic fracturing — a k a fracking — for natural gas in Pennsylvania, does it occur? No, say the gas companies (and many geologists). A new paper adds a “but.”

Many Say It Can’t Happen There

Extracting natural gas from shale deposits involves fracturing the rock about a mile (or more) beneath the surface by pumping high volumes of water, sand and a mix of chemicals at high pressure into the shale.

The aquifers that provide drinking water in the region lie a mere 30 to 100 yards beneath the surface.

And between the shale and the aquifers lie a mile or more of solid rock.

There’s no way, some argue, that stuff liberated by the fracking way down in the shale can get into the aquifers a mere 100 yards below the surface.

Yeah, but …

The argument seems to make sense and yet there’s this nagging question: Why are so many people in Pennsylvania experiencing problems with their drinking water near where the fracking is occurring? Also, why did a group of scientists from Duke find evidence of significant contamination of thermogenic methane (i.e., gas produced in shale) in water wells near fracked wells?

Can you explain these as mere coincidences with no cause-and-effect relationship? Perhaps, but it seems unlikely to me. Too many coincidences.

Or is it the result of sloppy and careless work (such as the installation of faulty casings) on the part of a few “bad apple” drillers? That seems much more likely.

The one explanation that seems least likely is that there are actual pathways by which gases and/or fluids from the shale formations could migrate upward into the aquifer. However, the findings reported in a paper by Nathanial Warner of Duke University and colleagues recently published in the Proceedings of the National Academy of Sciences suggest that such an explanation is not outside the realm of possibility.

Geochemical Sleuthing Uncovers a Natural Pathway for Contamination

Following up on the team’s earlier work [pdf] documenting methane contamination of drinking water in Pennsylvania, the authors analyzed 426 shallow water samples taken both recently and in the 1980s (well before Pennsylvania’s current natural gas rush) from a six-county region in Pennsylvania. They compared them to 83 Appalachian brine samples from deep formations.

Each water sample underwent a battery of chemical analyses, and the researchers documented concentrations of a myriad of dissolved substances including chloride, bromide, sodium, strontium, manganese, carbonate, and sulfate. Based on these analyses, the authors identified four general categories of surface water: two with low salinity and two with elevated salinity. Of the two with high salinity, one had a composition that was “similar to brines found in deeper Appalachian formations (e.g., the Marcellus brine). This suggests mixing of shallow modern water with deep formation brines.”

Still, No Smoking Gun

The implications of the Warner et al data are striking. It suggests that there are natural pathways by which deep brines from the Marcellus can percolate upward and mix with shallow aquifers. If such pathways exist, then they could, at least in theory, provide a conduit for gases and fluids associated with fracking to eventually find their way into aquifers and then into people’s drinking water.

Theory’s one thing, but has it actually happened? The authors find no evidence of any fluid contamination from fracking via this mechanism. The composition of the surface water samples that look like Marcellus brine are virtually identical to the composition of water samples taken from these sites in the 1980s — well before the fracking in the area began. In other words, the brininess of the sample is not due to recent fracking or any drilling for that matter.

Study Results Leave Door Open to Potential Contamination

However, the Duke team does not rule out the possibility that the methane contamination they have already observed in some drinking water wells may be related to migration through these pathways, and that fluid contamination could eventually occur.

“The possibility of drilling and hydraulic fracturing causing rapid flow of brine to shallow groundwater in lower hydrodynamic pressure zones is unlikely but still unknown. By contrast, the time scale for fugitive gas contamination of shallow aquifers can be decoupled from natural brine movement specifically when gas concentrations exceed solubility (approximately 30 cc∕kg) and forms mobile free phase gases (i.e., bubbles).”

Regardless, the authors point out that their work does suggest the need for a good deal more caution than some have argued as reasonable.

“The coincidence of elevated salinity in shallow groundwater with a geochemical signature similar to produced water from the Marcellus Formation suggests that these areas could be at greater risk of contamination from shale gas development because of a preexisting network of cross-formational pathways that has enhanced hydraulic connectivity to deeper geological formations.”

So it seems possible that the region’s geology is not quite as isolating or separated as some have suggested, and is a lot more connective. The Warner et al study seems to suggest that underground connections could allow contaminants to flow from the deep formations to shallow aquifers. Is it proof positive? Of course not. But maybe it’s enough of a coincidence to suggest that we at least hold off on fracking in regions that are the source of water for millions of people such as the Susquehanna and Delaware River watersheds?


  1. Barleysinger
    January 24, 2014, 2:35 am

    No Stan, I want

    1) people to admit there are ALTERNATIVE and have been for over 30 years (but no large company will due their part just yet )

    2) YOU PERSONALLY to go and live in the middle of a BIG fracking industry area with wells everywhere, and open air ponds that give off gases that burn your eyes – with all your money and life put into your house & land which is now surrounded by fracking ponds, tanks, and wells…

    and then live there – with no ability to move (who would buy THAT house) unless you don’t mind bankruptcy and probably homelessness for your whole family.

    Then while you live with natural gas coming out of your house pipes from the only water you can afford…from the SAME well that other people got good sweet water out of for over 100 years…with the water in your bath tub smelling like turpentine…and your kids so sick they can;t go to school and their skin covered in red painful rashes…

    Then go and talk to locals who have been there 3 generations on the very same properties. Talk to the oldest people there that you can find, about their water quality in the past – and how it was until a few years ago when the fracking started and they were so happy at first to have money around again – until their water was too bad to use (and they need to have it trucked in every day now)

    and you can (probably will) call it a coincidence even though ti happens EVERYWHERE they frack

    or say people need the energy (what good is it if you are dead)

    and YOU can live in that mess
    with your kids getting sicker every day

    The rest of the world, will just stay very far away from the insane USA, with the land of many parts of North America being destroyed forever….big swaths of land that will NEVER be safe to live on again (water polluting the topsoil from way down deep, through horizontal fractures & unresearched networks of aquifers )

    and the rest of humanity will swap technologies as fast as we can mange to

    * Brazil imports NO oil at all
    * Germany is shutting down its nuke plants
    * there are new batteries which use SUGARS and hold more charge for longer
    * SPAIN has had base line solar power at GOOD prices … with evening heat storage for over a decade) with

    we will change how we live with the same vigor which the US government uses to spy on people., throw away its ethics and constitution, and go to war for oil

  2. bob sargent
    west colo
    December 14, 2012, 9:26 pm

    it would seem wise not to mess with mother nature for a cost to the enviornment. ie the atomic bomb for one. is it not time for solar development? yes the oil and gas co’s would take a hit but are they not rich enough, bp claims of billions to clean up the mess they made from profits. will that area ever return to normal? how could it? follow the money trail folks as do our 3 branches of fiat gov does.

  3. Bill Chameides
    September 24, 2012, 3:46 pm

    Stan: Maybe so, but should that be the sum total of our energy policy?

  4. joel wischkaemper
    July 26, 2012, 8:21 pm

    They drop ten or twelve wells over a huge areas they proved with sound waves and presume to know what they are doing. BEFORE all the ground water is destroyed, why don’t they go someplace where they have already fracked and find out what happened. Why don’t they go there, drop more wells and find out just how good the acoustical examination of the sub surface is.

    I would love to bet on this one. At some point, it is going to be a giant Oops with an “I am soooo sorry.” But the ground water is going to be gone.

  5. Al
    July 26, 2012, 6:08 pm

    “No, say the gas companies (and many geologists)”

    -> you forgot to mention in this article: and *their* geologists, like *our* affiliates

  6. Michael
    Los Angeles
    July 23, 2012, 6:50 pm

    Fracking is totally unecessary as the largest crude oil and natural gas deposit ever discovered was covered up by a bulldozer in Prudhoe Bay Alaska to keep the price high for the Illuminati.

  7. Ben Marble, M.D.
    Mississippi Gulf Coast
    July 22, 2012, 4:14 am

    The author overlooks the obvious source of the problem i.e. the poisons can easily reach the drinking water level directly through the hole drilled in the earth….can anyone say NO DUH? Still not convinced then try a simple experiment…
    fill a balloon to the max with water then bury it under a few feet of sand then take a long straw or cylinder and push it downward through the sand into the pressurized balloon & the water will come up through the straw (if there is enough pressure in the balloon). The people who claim to be scientists who say this isn’t possible need to find a new line of work.

  8. Mel Sweet
    Reno, NV
    July 21, 2012, 11:14 pm


    I hope we can continue to frack for NG and create a good economy. But please do not at any moment think it is more valuable than our eco system.

    Therefore lets continue to Frack and lets continue to test. If we contaminate the water… is their a better way that is still economical? Then lets do it. If we can’t get the damned gas out without running our environment and eco system… then its time to find something else.

    United States
    July 21, 2012, 1:58 am

    out of thousands of wells
    drilled, very very few problems.
    and you want us to stop extraction
    and import more oil.