Natural gas extraction via hydraulic fracturing has been linked to contamination in groundwater.
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By Jeff Tollefson of Nature magazine
The US Environmental Protection Agency (EPA) sparked a firestorm in December last year when it released a draft report suggesting that the use of hydraulic fracturing — or 'fracking' — to extract natural gas had contaminated groundwater near Pavillion, Wyoming. Industry officials have long denied that fracking affects groundwater, and Pavillion has become the first high-profile test of this claim. On 26 September, the US Geological Survey (USGS) released data showing the presence of groundwater contamination in the region. Although the data would seem to support the EPA’s assessment — as does an independent analysis released by environmental groups this week — the survey did not seek to determine the source of the contamination. Nature examines the on-going debate and how it relates to broader questions about groundwater contamination from fracking across the United States.
How did this investigation begin?
After local landowners complained about the smell and taste of their water, the EPA began in 2009 to analyze the groundwater outside Pavillion. The agency tested the water in the shallow wells that tap the groundwater above the 169 gas-producing wells in the field; in two municipal wells in the town; and in several surface and deep wells that it drilled for monitoring purposes. It found evidence of contamination in both the shallow and deep wells, and attributed the shallow contamination to the 33 or so nearby surface pits used to store drilling wastes. The pits could not, however, explain the contamination in the deeper groundwater.
What is the evidence that fracking contaminated the deep groundwater?
A range of hydrocarbons showed up in the deep wells, as did some synthetic organic chemicals associated with fracking fluids and drilling activities. The EPA also found high pH levels that could be explained by potassium hydroxide, which was used as a solvent at the site. The agency also analyzed the evolution of the pollution plume to determine that groundwater seems to be migrating upward, suggesting that the source of contamination came from the gas production zone rather than the surface pits.
Officials with both industry and the state of Wyoming questioned the EPA’s data as well as its interpretation, arguing that some hydrocarbons are to be expected through natural migration from the gas field. The state then asked the USGS to conduct a new analysis and provide the data to the state. The USGS provided those data last week; it also sent samples to the EPA, which is conducting its own analysis.
What do the latest results suggest?
The USGS provided only the raw data and no interpretation. A spokeswoman for the EPA has said that the results are consistent with the agency's findings, and an analysis by environmental groups released this week confirmed that. A scientist who has investigated possible contamination at other sites, Rob Jackson of Duke University in Durham, North Carolina, says that multiple lines of evidence are certainly “suggestive” of fracking as a source of contamination.
Does this settle the debate?
No. Encana Corporation, an energy producer based in Calgary, Canada, that has wells in the field near Pavillion, maintains that neither the EPA draft report nor the USGS results provide any proof that drilling operations are to blame.
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13 Comments
Add CommentRequire that companies who use fracking techniques include an unambiguous marker in their fluids. Simple.
Reply | Report Abuse | Link to thisYeah, they've resisted that for decades, tooth and nail.
Reply | Report Abuse | Link to thisThere's a huge amount of word gaming going on here. When the wells are very deep, the contamination is unlikely to come directly from the fracturing process ("Fracking" itself is literally not to blame) but as mentioned from leaks from the shafts drilled to reach the depths.
Reply | Report Abuse | Link to thisSo the oil companies can go around and say that fracking is safe and be literally, but not factually correct. They cannot guarantee that the wells stay sealed all the way down to prevent leaching of methane, fracking chemicals, etc into various water sources.
And they desperately don't want to see regulation of the storage and disposal of the huge amount of waste water generated in the process.
oh bull
Reply | Report Abuse | Link to thisI do not understand why the regulators do not require tagging of fracking fluids. The drillers would not have to disclose their "secret sauce" and there would be no question about whether or not contamination was caused by fracking fluids. They do it with high explosives; why not fracking fluid?
Reply | Report Abuse | Link to thisAnd why does there seem to be no data on areas where fracking has not been done? There seems to be no established background contamination levels in water wells which tap aquifers that lie over gas. I used to live in an area where a number of the water wells had natural gas; pump houses required ventilation to avoid explosions. There had been no gas well drilling, and certainly no fracking, in that area.
Reply | Report Abuse | Link to thisThat said, tagging seems to be an intelligent approach.
If it walks like a duck and quacks like a duck........ What do you with (not so )common sense think of this. If there was no contamination before fracking AND now there is after fracking, what is the ONLY logical conclusion? And I'm sure the crooked drilling companies (who have padded the correct pockets, I'm sure) will find SOMEONE who will argue their point, and give resonable doubt. We will only be able to prove the fact for sure in a generation or two when kids are dying of unheard of cancers and adults have liver and kidney issues. Sometimes the obvious amswer is the right one. Duhhh!!!!
Reply | Report Abuse | Link to thisIt is not suprising that you find methane in wells that are drilled into the source rock. The source rock is unusally shallow in Wyoming. The EPA drilled thier wells too deep. Remember that Drake's well was 67 ft deep.
Reply | Report Abuse | Link to thisI can't believe an investigation is needed to know fracking is a bad idea. Of course groundwater (and in the end, surface water) gets contaminated when chemicals are pumped underground! And truly confined aquifers are very rare. Doesn't everyone know, water goes downhill? At some point, everything that is capable of seeping into the ground ends up in ground water and surface water. Gravity. Physics 101. Common Sense.
Reply | Report Abuse | Link to thiskaebomb, "Doesn't everyone know, water goes downhill?" Without getting into an argument, but have you seen a spring? Water in the ground percolates and flows in all directions, including 'up'. Surface water can rise and form fog and clouds. Nitpicking, I know, but common sense also.
Reply | Report Abuse | Link to thisWhy aren't concerns about contamination and fracking on the presidential debate subjects list ?
Reply | Report Abuse | Link to thisAnd fracking-waste injection sites have nothing to do with earthquakes in areas of Texas that had previously never experienced earthquakes.
Reply | Report Abuse | Link to thisIt's all just coincidence.
That would make sense if the goal by the political powers was to find out rather of not fracking was cotaminating the water. However the possibility that result would suggest it is not, makes it not worth taking the chance to actually test, when the industry can be destroyed by propoganda alone to the best interest of the financial backers of the current administration.
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