Fracking Chemicals in Pennsylvania Drinking Water

A natural gas well in Bradford County, Pa., where a study found that three households had traces of 2-Butoxyethanol or 2BE, a compound found in Marcellus Shale drilling fluids

An analysis of drinking water sampled from three homes in Bradford County, Pa., revealed traces of a compound commonly found in Marcellus Shale drilling fluids, according to a study.

The paper, published in theProceedings of the National Academy of Sciences, addresses a longstanding question about potential risks to underground drinking water from the drilling technique known as hydraulic fracturing, or fracking. The authors suggested a chain of events by which the drilling chemical ended up in a homeowner's water supply.

The industry has long maintained that because fracking occurs thousands of feet below drinking-water aquifers, the drilling chemicals that are injected to break up rocks and release the gas trapped there pose no risk. In this study, the researchers note that the contamination may have stemmed from a lack of integrity in the drill wells and not from the actual fracking process far below. The industry criticized the new study, saying that it provided no proof that the chemical came from a nearby well.

In 2012, a team of environmental scientists collected drinking water samples from the households' outdoor spigots. An analysis showed that the water in one household contained 2-Butoxyethanol or 2BE, a common drilling chemical. The chemical, which is also commonly used in paint and cosmetics, is known to have caused tumors in rodents, though scientists have not determined if those carcinogenic properties translate to humans. The authors said the amount found, which was measured in parts per trillion, was within safety regulations and did not pose a health risk.

Dr. Brantley said her team believed that the well contaminants came from either a documented surface tank leak in 2009 or, more likely, as a result of poor drilling well integrity.

The nearby gas wells, which were established in 2009, were constructed with a protective intermediate casing of steel and cement from the surface down to almost 1,000 feet. But the wells below that depth lacked the protective casing, and were potentially at greater risk of leaking their contents into the surrounding rock layers, according to Dr. Brantley.

In April 2011 the three homeowners in Bradford Countysued the drilling company, Chesapeake Energy Corporation, over reports of findingnatural gasand sediment in their drinking well water. In May of that year, the Pennsylvania Department of Environmental Protectioncitedtheoiland gas company for violating the Pennsylvania Oil and Gas Act and Clean Streams Law by lettingnatural gasenter the drinking wells, though the company admitted no fault. In 2012, the homeowners settled the lawsuit and the company bought the three households.

As a result of that suit, the state environmental protection agency recommended that the drilling company require that their wells extend what are known as intermediate casings beyond 1,000 feet.

Dr. Brantley described the geology in northern Pennsylvania as being similar to a layer cake with numerous layers that extend down thousands of feet to the Marcellus Shale. The vertical fractures are like knife cuts through the layers. They can extend deep underground, and can act like superhighways for escaped gas and liquids from drill wells to travel along, for distances greater than a mile away, she said.

Katie Brown, an energy consultant with Energy in Depth, an advocacy group for the Independent Petroleum Association of America, said the authors had no evidence that the small traces they found of 2BE, which is also used in many household items, came from a drilling site.

"The entire case is based around the detection of an exceedingly small amount of a compound that's commonly used in hundreds of household products," Ms. Brown wrote in an email. "The researchers suggest the compound is also found in a specific drilling fluid, but then tell us they have no evidence that this fluid was used at the well site."

Garth T. Llewellyn, a hydrogeologist with Appalachia Hydrogeologic and Environmental Consulting and the lead author of the report, said that when his team sampled water wells that were farther away from the drilling sites, they did not find any of the compounds found in the three households. "When you include all of the lines of evidence, it concludes that that's the most probable source," he said.

Source: NYTimes

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Taxonomy

• Pollution
• Fracking
• Water Supply