I found this:
MANY people are convinced that fracking is the source of gas and oil in well water. I’ve kept an open mind, while suspecting the conclusions might be premature.
Organic compounds found in drinking water aquifers above the Marcellus Shale and other shale plays could reflect natural geologic transport processes or contamination from anthropogenic activities, including enhanced natural gas production. Using analyses of organic compounds coupled with inorganic geochemical fingerprinting, estimates of groundwater residence time, and geospatial analyses of shale gas wells and disclosed safety violations, we determined that the dominant source of organic compounds to shallow aquifers was consistent with surface spills of disclosed chemical additives. There was no evidence of association with deeper brines or long-range migration of these compounds to the shallow aquifers. Encouragingly, drinking water sources affected by disclosed surface spills could be targeted for treatment and monitoring to protect public health. [emphasis added by me]
To me, surface spills/leaks are a wild card in this that, for some reason, I missed as a possibility. And it makes sense.
It never DID make sense to me that fracking at the great depths it is used (5,000-20,000 feet deep) could cause such problems in well water only a few hundred feet deep. HOW could the gas or oil GET up to the aquifers? The ONLY interface between the aquifers and the fracking was the piping that transported the gas upward through the aquifer levels. I worked on some drilling pipe heat treating projects long ago, and I learned at least a little bit about these pipes. I DOUBTED that leakage at the aquifer level was probable or even possible, because the oil industry doesn’t want to waste the gas or oil that they went to such expense to get. I.e., leaks cost money (and that is the bottom line, literally). Dollars COUNT to them. And it is so simple to prevent leaks (and thereby save money) with good welding and good joint design of the pipe connections. To me, it seemed unlikely that they would be sloppy about these joints because it would cost them money. AND it would be found out sooner or later, causing a BIG problem for them, PR-wise, and otherwise (cleanups!).
If the leaks were possibly far below, where the fracking occurs, then the gas or oil would have to migrate upward a LONG way. This, to me, seemed also incongruous. The gas or oil had not migrated on its own during its lifetime, so it seemed odd that the fracking so far down below would aid the migration at higher levels, even if they DID change the conditions at the fracking level. and no one had to my knowledge suggested that the leaks were up the shaft somehow. (And why would such shaft leakage occur only on fracked wells, and not on all the hundreds of thousands of wells drilled since the 1800s? No, it seemed SOMETHING ELSE was going on. But I didn’t know what.
So, I sat and waited, hoping something would come along and provide an explanation.
This paper seems to point at one.
As an engineer, the most significant part of this is, “inorganic geochemical fingerprinting“. This means that they have tied the well water pollutants to a specific source, and that that source is not fracking.
To me, this is pretty much PROBLEM SOLVED.
But at the same time this is the first such a finding, so perhaps it is not true everywhere. But it IS true in the biggest shale formation in the NE USA.
In addition, an encouraging note: If it is surface spills, then THAT is something that can be dealt with – in normal, already existing ways. That is good!
And if this all is true (and it seems to be), then fracking is much less dangerous than many had thought.
(For the earthquake-fracking possible danger, see my post at A Look at Fracking-Earthquake Claims.)