A pair of studies released today by the U.S Geological Survey found low-to-moderate concentrations of naturally occurring methane in private water wells in Wayne and Pike Counties– a region of the state without Marcellus Shale drilling.
Those two counties fall under the jurisdiction of the Delaware River Basin Commission, which currently has a moratorium on fracking.
“These baseline studies are very important,” says USGS researcher Ronald Sloto. “People are very concerned about the environmental impact of shale gas drilling. In order to assess the impact of something, you need a ‘before’ and an ‘after’. Then you compare the two and see what the changes are.”
The samples were collected between 2012 and 2013. In Wayne County, Sloto examined 34 private water wells and found 65 percent had some level of detectable methane. Ten percent of the wells had relatively elevated levels of methane. In Pike County, 80 percent of the 20 tested wells had detectable methane, and again, only 10 percent had elevated levels.
The researchers note that the existence of naturally occurring methane does not absolve the gas industry of its role in contaminating some water supplies. Methane can be naturally occurring, but it can also migrate into water supplies through faulty well casings.
“But in the case of Wayne and Pike counties, the methane we’re measuring is all naturally occurring,” says Sloto.
The results are in line with another USGS study conducted in New York’s Southern Tier in 2012, which found naturally occurring methane was common in private water wells. New York also has a moratorium on shale gas drilling.
Pennsylvania does not regulate private water wells, so in some cases it has been difficult to determine if methane contamination pre-dates gas drilling. Companies now do baseline water testing before they begin development, and the state’s 2012 oil and gas law, Act 13, expanded the presumption of liability for water contamination
USGS researcher Lisa Senior says the Wayne and Pike County studies also looked at a host of other water contaminates, including chlorides, sodium, strontium, arsenic and barium– which can be associated with fracking wastewaster.
“We tried to get a comprehensive characterization of existing groundwater quality,” says Senior.
There were a few wells that had arsenic concentrations exceeding federal drinking water standards, but Senior says, in general, both counties had good water quality.