What is happening with chemicals in fracking?

Please notice the word “possibly” in your Viewpoint article on “fracking” The Alpena News, July 23, 2013.

If chemicals added to our water cannot defy gravity and come back up into the groundwater, then what about the millions of gallons of freshwater that are mixed with those chemicals? Do they stay down too? Are we exchanging our fresh water for gas and oil?

Doris E. Lance