According to a study published in April in the journal Ground Water, it's not a matter of if fluid will move through rock layers, but when.
Tom Myers, a hydrologist, drew on research showing that natural faults and fractures are more prevalent than commonly understood to create a model that predicts how chemicals might move in the Marcellus Shale, a dense layer of rock that has been called impermeable. The Marcellus Shale, which stretches from New York to Tennessee, is the focus of intense debate because of concerns that chemicals injected in drilling for natural gas will pollute water.
Myers' new model said that chemicals could leak through natural cracks into aquifers tapped for drinking water in about 100 years, far more quickly than had been thought. In areas where there is hydraulic fracturing or drilling, Myers' model shows, man-made faults and natural ones could intersect and chemicals could migrate to the surface in as little as "a few years, or less."
"It's out of sight, out of mind now. But 50 years from now?" Myers said, referring to injected waste and the rock layers trusted to entrap it. "Simply put, they are not impermeable."
Myers' work is among the few studies done over the past few decades to compare theories of hydrogeology to what actually happens. But even his research is based on models.
"A lot of the concepts and a lot of the regulations that govern this whole practice of subsurface injection is kind of dated at this point," said one senior EPA hydrologist who was not authorized to speak to ProPublica, and declined to be quoted by name.
"It's a problem," he said. "There needs to be a hard look at this in a new way."
From ProPublica.org (find the original story here); reprinted with permission.