Three-year study found no relationship between methane concentrations in groundwater and proximity to natural gas wells

May 19, 2018 by Michael Miller, University of Cincinnati
UC geology professor Amy Townsend-Small uses gas chromatography to study water samples taken from groundwater wells in Ohio. Credit: Jay Yocis/UC Creative Services

A study of drinking water in Appalachian Ohio found no evidence of natural gas contamination from recent oil and gas drilling.

Geologists with the University of Cincinnati examined drinking in Carroll, Stark and Harrison counties, a rural region in northeast Ohio where many residents rely on water from private underground wells.

The time-series study was the first of its kind in Ohio to examine methane in groundwater in relation to drilling. The results were published in the journal Environmental Monitoring and Assessment.

"Some people had elevated concentrations of methane in their groundwater, but the isotopic composition showed it wasn't from natural gas" said Amy Townsend-Small, associate professor of geology in UC's McMicken College of Arts and Sciences.

"What we found is in most cases it was probably from underground coal in the area or biological methane produced in groundwater."

UC researchers collected 180 groundwater samples in total at homes in the three counties. Some of the sites were sampled multiple times. In particular, researchers looked for evidence of methane, the primary compound in natural gas. They also studied changes in the acidity or pH of the water, and changes to its conductivity.

They found no increase in or composition in groundwater over the four years of the study, despite the presence of new shale gas wells drilled in the study area. Likewise, they did not find higher methane levels in closer approximation to shale drilling.

Researchers did find wide variability in methane concentrations in the drinking water, ranging from 0.2 micrograms per liter to 25.3 milligrams per liter, which is strong enough to catch fire in enclosed spaces. But researchers found no relationship between the methane observed in drinking water and the new gas wells.

"Clearly, additional monitoring is needed to determine whether methane concentrations and source signals in this region change as the number of oil and gas wells continues to increase," the study concluded.

A time-series map shows the Ohio counties where UC researchers collected water samples. Red circles indicate active natural gas wells. Blue diamonds are sites where time series groundwater samples were taken. Light blue circles represent sites where a single sample of groundwater was collected. Groundwater sample locations are noted when samples were taken between the years noted in each map. There was a large increase in active natural gas wells from 2013 to 2014. Credit: Claire Botner/UC

Researchers identified the chemical composition of the water using gas chromatography, isotope ratio mass spectrometry, and radiocarbon dating in a UC geology lab. Understanding the chemical composition helps identify the source of methane found in drinking water: from natural gas extraction, organic decomposition or even from the digestive systems of nearby cows.

Lead author and UC graduate Claire Botner said the study solicited participation by homeowners who were willing to let researchers test their wells.

The study area has seen increasing interest from natural gas companies in recent years. It's located above a geological feature called the Utica Shale formation, which is known to harbor oil and natural gas. When UC launched its methane study in 2012, Ohio had issued 115 drilling permits for the region. By the study's end in 2015, nearly 1,600 permits had been issued, primarily for Carroll County.

Hydraulic fracturing is a process by which pressurized water, sand and chemicals are pumped into natural-gas wells more than a mile deep to break apart shale to release pockets of oil and natural gas.

Researchers hypothesized that methane concentrations in the drinking-water wells they sampled would increase over time with the growth of in the area. This is a correlation researchers observed in Pennsylvania's Marcellus Shale region.

But that's not what UC's water tests revealed. The study concluded that methane observed in groundwater was "biogenic," or naturally occurring and independent of natural gas drilling.

"The study researchers in Pennsylvania thought the contamination issue was a failure of the well casings in the fracking wells," Townsend-Small said.

"Hopefully, that doesn't happen often. And that apparently didn't happen with the wells of homeowners we worked with for our study."

Townsend-Small has spent much of her career researching groundwater and methane. She and other UC geologists are studying the influence of the Great Miami River on groundwater in southwest Ohio at UC's C.V. Theis Groundwater Observatory. She also has studied in relation to algae blooms in the Great Lakes and methane in arctic lakes in Alaska.

UC graduate student Jacob Deighton uses a vacuum line to prepare a water sample in a geology lab. Credit: Jay Yocis/UC Creative Services
"Some people had elevated concentrations of methane in their groundwater, but the isotopic composition showed it wasn't from natural gas. It was from a different source," Townsend-Small said. "What we found is in most cases it was probably from underground coal in the area or biological produced in ."

Study co-authors included UC professor emeritus David Nash and UC assistant professor of geology Joshua Miller.

Botner said if researchers were to replicate the study, she might recommend expanding it to include other hydrocarbons such as propane or look for carbonate isotopes associated with natural gas drilling.

"It's a controversial topic," Botner said. "But that's why science is so valuable. Maybe another study would confirm our findings or maybe they would find something else. Regardless, we would welcome more well testing."

Carroll County Commissioner Robert Wirkner said the findings were good news for residents. Like many of his neighbors, he gets drinking water at his house from a private well on his property.

Wirkner said gas companies test the drinking water of nearby homes before and after they drill a well to observe any changes in water quality.

"My water has been tested multiple times," he said. "So we're happy to hear the findings."

Townsend-Small said protecting wells from contamination is especially important in rural areas because there are few alternatives for clean drinking water. Digging a new or deeper well is expensive and would not necessarily solve a pollution problem. And there are few opportunities in rural areas to connect to public water lines.

"It would be great if homeowners had access to ongoing monitoring," she said. "In cities, you are reassured that your is safe. We pay the public water utilities to test the water every day. But if you have a private well, you just have to hope that it's not contaminated on a day-to-day basis."

Explore further: Tapping a valuable resource or invading the environment? Research examines the start of fracking in Ohio

More information: E. Claire Botner et al, Monitoring concentration and isotopic composition of methane in groundwater in the Utica Shale hydraulic fracturing region of Ohio, Environmental Monitoring and Assessment (2018). DOI: 10.1007/s10661-018-6696-1

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19 comments

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TheGhostofOtto1923
1 / 5 (2) May 19, 2018
""It's a controversial topic," Botner said. "But that's why science is so valuable. Maybe another study would confirm our findings or maybe they would find something else."

-Stay tuned for the academie counter-study that concludes without doubt that fracking is killing us all. And declares that it is the conclusive, unequivocal last word and so need not be challenged.
koitsu
not rated yet May 19, 2018
Now if we could just get to the bottom of those pesky earthquakes in Oklahoma...
Eikka
2.3 / 5 (3) May 19, 2018
-Stay tuned for the academie counter-study that concludes without doubt that fracking is killing us all. And declares that it is the conclusive, unequivocal last word and so need not be challenged.


Well, one can already read between the lines that they averaged a bunch of measurements together to dilute the cases where the fracking indeed had contaminated the ground water.

Notice the distribution of the samples from the map.
Parsec
4 / 5 (4) May 19, 2018
These results and the research from Pa. showing that fracking does cause CH4 in groundwater is perfectly consistent. This simply means that it depends on the integrity of the fracking operation itself. In those places where there are breaches in the containment wall for whatever reason, usually voids beneath the ground that weaken or destroy the casing.

Given the value of fracking and the products from it, this just means that whenever we drill fracking wells we must do it very carefully. And monitor them continuously for leakage, and shutting them down immediately when leaks are detected.
dan78658765
1 / 5 (2) May 19, 2018
yes science is valuable, that's why companies donate to university departments, to buy them off
Thorium Boy
1 / 5 (1) May 19, 2018
Greenloon climate screechers wrong again, what a surprise! Just like with "peak oil" and "mass starvation by 1980!!! In fact, greenloon predictions are SO often wrong, one statistician suggested they violated the law of averages.
Da Schneib
5 / 5 (1) May 20, 2018
Sounds like it depends on the geology. Or maybe on who's doing the fracking, as @Parsec says.
ZoeBell
May 20, 2018
This comment has been removed by a moderator.
Da Schneib
not rated yet May 20, 2018
So did they do isotope studies to determine where the gas came from, @Zoe?
dlethe
1 / 5 (4) May 20, 2018
This is another story that you'll never see in the mainstream media. it conflicts with their anti-oil company bias.
TheGhostofOtto1923
1 / 5 (1) May 20, 2018
Well, one can already read between the lines that they averaged a bunch of measurements together to dilute the cases where the fracking indeed had contaminated the ground water
And one can apply the same sort of dubious amateur criticism to opposing studies.

So what?
Given the value of fracking and the products from it, this just means that whenever we drill fracking wells we must do it very carefully. And monitor them continuously for leakage, and shutting them down immediately when leaks are detected
And this diligence of course applies to all the other wells that have ever been drilled but not accused because they do not bear the same sort of ominous buzzword moniker "frack".

"Frack". Chills up my spine.
TheGhostofOtto1923
1 / 5 (1) May 20, 2018
For instance
In Duke study... fracking is evil
-but then

"Connor and Molofsky wrote a report in 2011 for the Oil & Gas Journal that challenges Jackson's findings. They find methane to be not only common in groundwater in northeastern Pennsylvania, but also more concentrated in valleys as opposed to higher elevations. They argue that geology, not compromised well casings, is to blame for methane contamination."
Ethane in those nearby homes was 23 times above that of homes farther away
Please reference studies which indicate these levels are injurious to health and further, are atypical of natural sources in these regions.

And I'll show you one that says they arent.
Turgent
1 / 5 (2) May 20, 2018
@ ZoeBell

The cited SA article is a "May". I live 10 miles north to the center of the Marcellus field. There has been absolutely nothing to support the conjecture that the wells put anything into the ground water. If it did the news media would be having an orgasm.

Between 2008 and 2014 the caterwauling of local Anti-Frackers was deafening. Radioactive C14, salt incursion into the aquifer, deadly chemicals in the fracking fluid, destruction of roads due to water truck usage, and on and on were the reasons life would end. There wasn't an objection they couldn't find. In Montrose, PA a couple actually injected methane into their water and lit the tap. This went on nation news. Might this get the attention of the know it all crowd? Its 2018 and nothing adverse has happened. The liberal ticks are taxing (at the well head) the bejesus out of it and bloating the compensation for public employee unions. Guess that makes it non-toxic.
Shootist
1 / 5 (2) May 20, 2018
Have you hugged a fracker today?

You should.
antonima89
1 / 5 (1) May 20, 2018
Why would they test for methane in the groundwater? It has low solubility and it is non-toxic. It seems like it should be the last thing to test for.
Da Schneib
3 / 5 (2) May 20, 2018
Why would they test for methane in the groundwater? It has low solubility and it is non-toxic.
A couple pretty obvious reasons:

1. Natural gas is mostly methane. If there's natural gas leaking into the groundwater methane is what you'd expect to find.
2. Methane is flammable. It's an explosion hazard if mixed with air. Not exactly what you want bubbling out of your drinking water.

I'd say that will do it.
ab3a
not rated yet May 20, 2018
2. Methane is flammable. It's an explosion hazard if mixed with air. Not exactly what you want bubbling out of your drinking water.


To get to the LEL you speak of, you need at least 5% of the volume of air. That's not easily done at the rates they're measuring in this article.

Further, note that the article does mention several sources of natural gas in water that are not nefarious in any way.
Turgent
1 / 5 (2) May 21, 2018
"2. Methane is flammable. It's an explosion hazard if mixed with air. " Yeah, when we were teens we used to light our farts. No one ever exploded and we kept the room from filling up with explosive beer farts.
Da Schneib
not rated yet May 22, 2018
Maybe you want to read the article before you comment.

Just sayin'.

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