No, fracturing fluid has not migrated into aquifers from underground.....from surface spills---yes.....but not from underground.
Also, I bet it was not natural gas, but methane in water. There is a difference.
Methane has seeped into ground water in certain areas of PA as a matter of historical fact. People could light the water from a tap for at least the last 60 years, probably as far back as when the water was first tapped. It has nothing to do with fracking. Don’t tell the idiots that made “Gasland” though. Their minds are already made up.