The study, published in the journal Environmental Science & Technology, found radium levels 200 times higher than normal in water downstream from the Josephine Brine Treatment Facility, which processes waste water from natural gas fracking operations. In addition to the radioactive radium, the water also contained bromide, which can create cancer-causing compounds when combined with chemicals used to treat water.

Joseph Stromberg at Smithsonian Mag has a good summary of how these naturally occurring compounds are made more dangerous by natural gas drilling:

Between 10 and 40 percent of fluid sent down during