Slick water and black shale in fracking do not combine to produce radioactive waste. Slick water is a mixture of water and chemicals used to lubricate the drill bit and transport rock cuttings to the surface during the hydraulic fracturing process. Black shale is a type of sedimentary rock that is not typically radioactive. While the process of fracking can release naturally occurring radioactive materials from the rock, these materials are typically in very low concentrations and are not considered to be a significant environmental or health risk.