Crystal Stroud is a 29-year-old hairdresser who lives in Marcellus Shale country, on a rural road in Bradford County, Pa., hard by a stream, across from a farm.

In February, a company called Chief Oil and Gas began drilling a natural gas well about 1,200 feet from her house. In March, she says, she started noticing clumps of hair falling out in the shower.

She was at the outset of an ordeal that raises questions as to whether natural gas drilling courts risks of water contamination that go beyond the process known as "fracking."

About a week after the hair in the shower, Stroud called to her husband in a panic:

 "I said ... oh my God there's something wrong and he put his hand to my chest and he said I can feel it, it's beating hard. I  said I feel like I'm out of breath constantly, when I shop, like grocery shopping.  Everyone said it sounds like anxiety attacks." 

Stroud's doctor prescribed Zoloft, an anti-anxiety medication. 

"So after taking the Zoloft for three days, I still had all of the symptoms, the shortness of breath, the heart racing," said Stroud. "Then my hands began to tremble." Stroud says her speech also was slurred.

A benchmark test

Like many in her area, Stroud was aware of the concerns about hydrofracturing, or fracking.   In that process, a solution of water, sand and chemicals is shot into a deep well to help release the gas.

When she saw the drill rig go up near her house, she had her well water sent for testing. She wanted to get a baseline, in case fracking ended up polluting her water.  But Stroud's health issues began before the well near her house had ever been fracked.

On April 11, she got a surprising call from the lab.

The woman calling said the water tests revealed "major concerns."

"I said well what do you mean major concerns? And she said well you have elevated levels of barium, manganese, lead, and gross alpha, gross beta, which are radiological materials," said Stroud.

Stroud mentioned her symptoms and the caller said barium had been known to cause similar symptoms.

"It is a public health concern for example she needed to know the barium in her water was really really high," said Carrie Davis, who works for Benchmark Analytics, the lab that Stroud used to test her water.  

Levels well above the limit

Barium is a heavy metal that can occur naturally. It's also used in drilling for oil and gas. It can be poisonous if drunk in large amounts. It can cause heart problems, as well as numbness around the face, muscle weakness, diarrhea, and an upset stomach. 

"She is almost two and a half times the maximum contaminate level. And that we don't see very often," said Davis. She says Stroud's water also had elevated levels of methane, chloride and lead. 

After hearing from the lab, Stroud and her 4-year-old son got blood tests. Both came back showing high levels of barium. 

Down the road from Stroud, Mia Root lives with her husband and two daughters. Her tests, by a different lab, showed even higher levels of barium _ 10 times the recommended level. But Root and her family do not drink their water, and say they have no symptoms. 

"I did use it for cooking and stuff of that nature; I would boil it," Root said. "But this guy told me flat out not to use it. He said, 'I'm surprised no one has had a heart attack.'"

Driller's probe shows no link

And although the mud used in gas drilling can contain barium, a spokeswoman from Chief Oil and Gas says no barium was used to drill the well near Stroud and Root.

The spokeswoman, Kristi Gittins, says Chief uses a synthetic mud that is environmentally friendly. Also, she said, Chief uses a closed-loop system, which means that all the cuttings and fluid from the drilling process go directly into a steel container and not into an open-air drill pit.

Gittins says Chief's investigation into Stroud's claims concluded its natural gas well could not have caused the contamination of Stroud's water. 

So where did the barium come from? 

While water wells may be 100 feet deep, natural gas wells must go much deeper to wrest gas from the earth, as deep as a mile.

Barium can occur naturally. But it's usually buried deep within the earth. Even before a well is fracked, some speculate, the drilling process might itself lead to drinking water contamination. 

Karl Markiewicz is a toxicologist with the Agency for Toxic Substances and Disease Registry (ATSDR), which is part of the Centers for Disease Control. 

"Whatever is in the rock thats there, the geologic formation, can be released," said Markiewicz. "We don't have empirical data showing this, but understanding the chemistry involved, it's possible." 

Markiewicz says connecting toxins in the blood with water contamination is difficult. Most people don't test their water before drilling. Even then proving a connection would not be easy.    

"When I say our science has not evolved with this industry, it really hasn't," Markiewicz said. "Things like that could be coming through in the ground water and barium is one that's associated with drilling, we know that. But boron, selenium and arsenic and other things are as well." 

Markeiwicz says these contaminants have shown up near drilling sites in Texas, Oklahoma and Colorado, so it doesn't surprise him to see them now in Pennsylvania water wells. In fact, a group of residents in Sugar Run, Pa., not far from where the Strouds live, reported similar contamination and symptoms, based on water and blood tests, before the well was fracked. 

One person who is not surprised by this is Dr. Theo Colborn. Colborn is the president of the Endocrine Disruption Exchange, which tracks how chemicals in the environment affect people's health.  She says many people start exhibiting symptoms before a well is fracked. And she agrees that tracing a source of contamination can be mysterious. 

"So even underground, no two locations are going to be identical," said Colborn. "If the people were higher up, their probability of having this reach their water was far less.  If she's down in a draw of course she's going to be more exposed." 

Is Stroud case an omen? 

 The CDC's Markiewicz says the case of Crystal Stroud's water and her elevated barium levels could be a harbinger of more to come as natural gas production expands across Pennsylvania. 

"I don't think we as public health officials have a good handle on what's going on at 5,000 or 6,000 feet below the ground and how that's impacting a well that's 100, 200 or 600 feet," said Markiewicz.

Back in Bradford County, a thousand-gallon jug filled with trucked-in water sits on Crystal Stroud's front lawn, next to a swingset.  Such containers, known as water buffaloes, dot Bradford County _ signaling to every passer-by another contaminated well.  Stroud says after she stopped drinking her well water, her symptoms have subsided. But she worries about long-term effects, and the health of her son.

Stroud says she feels her home has been stolen from her and she wants it back.  

"That's it. A few people have asked me that and they say well you obviously can't have that but that's what I want," she said. "I want our home back." 

Stroud says she contacted real estate agents about selling her house.  But once they hear about her contaminated well, they stop returning phone calls.  Houses without water are worthless.