The combination of old mines and Marcellus Shale gas drilling may have contaminated the water wells of some Connoquenessing Township residents, according to a study by a Duquesne University professor.

John Stolz of the Center for Environmental Research and Education at Duquesne University on Saturday presented at the Butler Public Library his findings into the contamination of private water wells in the Woodlands housing development in the township.

“Essentially what I’ve been able to establish is there has been a change in the water quality in this community that is concurrent with the new development of putting in 15 well pads and 65 laterals,” said Stolz, who researches water contamination around Southwestern Pennsylvania.

Stolz, who spoke at a meeting sponsored by Marcellus Outreach Butler, is a professor of environmental microbiology.

The Woodlands neighborhood consists of nearly 200 homes.

Rex Energy began drilling unconventional natural gas wells in the area in 2009.

Stolz said there are 15 pads and 65 horizontal wells within 2.5 miles of the Woodlands.

Stolz and his students surveyed 143 residents in the area in October 2012.

Of that number, 63 reported no change, 56 indicated a change in water quality or quantity since drilling began and 24 replied they were uncertain.

Stolz’s team tested the water from 33 homes.

“Twenty-five of the 33 samples we tested had high levels of manganese,” Stolz said, adding the chemical is mostly associated with legacy coal and oil mines. “When you think manganese, you think mine drainage.”

Stolz said the water was not contaminated with microorganism like E. coli, ruling out agricultural causes.

“The main concern is that when you drill in Pennsylvania, you have to recognize the fact that we have legacy issues,” he said, adding there are about 300,000 abandoned mines in the state.

Stolz believes the amount of pressure used in unconventional drilling has released contaminants from those pre-existing mines.

“The idea is when they do all this in a short period of time, it can cause movement of pre-existing stuff,” he said.

The study also showed the change in conductivity in water of two homes tested on a daily basis, meaning different levels of contaminants varied daily.

“You have a serious problem when your water quality changes from day to day,” Stolz said.

But while some residents have had issues with water, others have not.

“There is good water in the Woodlands, and there is bad water in the Woodlands,” Stolz said.

The variance can come from a variety of factors, including topography, the type of water well and the depth of the well.

Depth of the water wells surveyed in the Woodlands ranged from 62 feet to more than 900 feet, Stolz said.

Both Rex Energy and the state Department of Environmental Protection have studied water issues in the development and have issued reports stating the drilling has not affected the Woodlands’ water.

But residents have reported water problems since the drilling began.

More than 30 families get their drinking water from a voluntary water bank at the White Oak Springs Presbyterian Church on Shannon Road, a few miles from the Woodlands.

“It’s one of those things where what the DEP says and what the company says often don’t go along with what the homeowner says,” Stolz said.

He said the state’s regulations on water don’t protect residents from water contamination associated with fracking.

“According to the DEP, there have been only 26 complaints (on water quality) in Butler County,” Stolz said. “They found that zero were caused by companies.”

Stolz said the state’s tests are flawed because they don’t even report on the main contaminants resulting from fracking. He said the DEP has two lists for contaminants found in water, separated by the dangers of the contaminant.

“This is where we get into a lot of problems because those are considered cosmetic,” he said. “Meaning that it’s taste and smell. But it is going to make you sick if you have high concentrations.”

Bromide and chloride, two contaminants most associated with fracking, as well as manganese are listed as cosmetic contaminants.

Stolz said another problem with recognizing a possible problem comes from settlements between landowners and drilling companies.

“If a landowner has problems, and they settle with the company, the DEP does not file a violation,” Stolz said.