Does Fracking Pollute Groundwater?

ProPublica posted a story yesterday entitled, “New Study: Fluids From Marcellus Shale Likely Seeping Into PA Drinking Water,” which describes how new research has concluded that salty, mineral-rich fluids deep beneath Pennsylvania’s natural gas fields are likely seeping upward thousands of feet into drinking water supplies.

Another paper published on Monday by Duke University researchers found that gas drilling in northeastern Pennsylvania did not contaminate nearby drinking water wells with salty water, which is a byproduct of the drilling.

So which is it? Is fracking polluting groundwater or not? The answer depends on how you want to frame it. (Grist, 7/10/2012)