Frac Sand Mines: Are they contaminating water?

We have been inundated with the word "fracking."  Most people now recognize that word and know a little bit about it.  But the gas industry would love to distract us with that word, and in some cases, use truthiness to claim that fracking is safe, which, of course, it really isn't, and never will be.  So we have to spread the word that fracking is only a small part of what is wrong with fossil fuel extraction.  We now know about pipelines, spills on well sites, air pollution, noise pollution, truck traffic, and, perhaps the newest worry which has actually been around all along: frac sand mines.  We are starting to notice the ill effects of silica sand and possible water contamination at frac sand mines. 

Here is a news report and article about this issue from Trempealeau County, Wisconsin.

To investigate further, check out this link which discusses the detrimental health effects of acrylamide.  The news report referred to above states:

"Polyacrylamide is used to wash frac sand. It contains the chemical acrylamide, which studies have linked to cancer. The Guza mine in Trempealeau County is allowed to use polyacrylamide in its settling ponds, but the pond must be lined with concrete. During an investigation last week at the mine, Trempealeau County officials discovered two ponds did not have that concrete. Now the mine's neighbors are concerned their drinking water is contaminated."

One of my questions is this: Isn't concrete permeable?  I think it is.  The same kind of problem happens with fracking wastewater ponds which are supposed to be lined with plastic.  I have personally seen with my own eyes these plastic liners falling in on themselves, allowing contaminated frackwaste to seep into the soil.  And several years ago I saw a video showing a bulldozer pushing a liner under the dirt as a well pad was being closed down.  The point is that there are many examples of procedures going awry.  And there is little oversight.