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Bromides Found In Allegheny River

PITTSBURGH (KDKA) -- There may be another potential threat to the area's drinking water and while the cause is unknown, natural gas drilling is one of the suspects.

In the past, there have been problems in the Monongahela River with bromides, salty substances which can become carcinogenic when treated in water treatment plants.

KDKA Investigator Andy Sheehan has discovered that same problem now exists in the Allegheny River – the water supply for the City of Pittsburgh and a host of other cities and towns.

"So whenever there's any suggestion that something may have changed with the quality, we're all over that," Stanley States with the Pittsburgh Water and Sewer Authority said.

Several months ago, when the PSWA found elevated levels of bromides in the intake water, it raised a red flag. That's because when they are combined with chloride in the treatment plant, bromides become a dangerous compound called trihalomethanes.

At PSWA, they had never been concerned about bromides and trihalomethanes in the past, but in the testing lab, they have tracked a steady increase over the past six months.

The drinking water is still within safe water standards, but could be approaching unsafe levels, especially for the most dangerous trihalomethene called bromoform.

"And that bromoform is disconcerting, because we never see bromoform here," Mark Stoner, with the PSWA said.

Sheehan: "So this was a cause for alarm."

Stoner: "Correct."

The question is why now.

"One possible explanation is that bromide levels in the river may have increased associated with Marcellus Shale mining operations," States said.

These bromides can come from acid mine runoff and coal-fired power plants, but States says what has changed on the river in the past two years is the amount of natural gas drilling wastewater being treated at plants.

And while the problem is manageable now, he says regulators need to make sure it stays that way.

"We are still in compliance. We're definitely in compliance," he said. "We're concerned that this is an unusual increase that's still in compliance. We don't want this to get any worse."

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Pittsburgh Water and Sewer Authority

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