"PITTSBURGH -- The U.S. Coast Guard is seeking public comments on a proposal that would allow barges to transport shale gas wastewater, a drilling byproduct that can include chemicals, radioactive material and heavy metals."
"Some states, such as Texas, have large numbers of underground wells where the wastewater can be disposed. But Pennsylvania — where a recent boom in shale gas drilling is producing tens of millions of gallons of wastewater every year — has only a few such disposal wells.
Extracting the gas trapped in shale formations requires pumping hundreds of thousands of gallons of water, sand and chemicals into the ground to break apart rock and free the gas. Some of that water, along with large quantities of existing underground water, returns to the surface, and it can contain high levels of salt, heavy metals and low-level radiation."