A new study has shockingly shown that fracking wastewater, even after being treated, is still contaminating drinking water.

Wastewater from hydraulic fracturing, or "fracking," and its toxic byproducts have long been an issue, especially for those who are concerned that flowback may be contaminating their groundwater.

Fracking involves injecting millions of gallons of fluids into shale rock formations to release oil and gas. The wastewater generated during this process is highly radioactive and contains high levels of heavy metals and salts called halides, like bromide, chloride and iodide. The most traditional approach to dealing with this wastewater is to treat it in municipal or commercial treatment plants and then release it into rivers and other surface waters.

But the problem is, as described in the American Chemical Society journal Environmental Science & Technology, the new research has found that discharge of fracking wastewaters to rivers, even after passage through wastewater treatment plants, could be putting the drinking water supplies of downstream cities at risk.

So how are these chemicals slipping through the cracks? Researchers have raised concerns that, as stated in the press release, that plants aren't efficient at removing halides. Typical treatment methods involve chlorination or ozonation, but this can lead to the formation of toxic byproducts.

To test the effectiveness of these methods, researchers diluted river-water samples of fracking wastewater discharged from operations in Pennsylvania and Arkansas. Then, after using current drinking-water disinfection methods on the samples, they found that even at concentrations as low as 0.01 percent up to 0.1 percent by volume of fracking wastewater, a host of toxic compounds formed.

Their recommendation to eliminate this problem is to do away with discharging fracking wastewater into surface waters all together, or implementing specific halide-removal techniques to all future water treatment.