Of all of the radioisotopes brought to the surface during drilling, radium, particularly 226Ra and 228Ra, is of the greatest concern for human health and the environment. First, these isotopes are soluble in water. This means that their concentrations can be high in the formation water that comes to the surface after wells are drilled and fractured.
Radium can precipitate out of thewater along with salt, which concentrates the radium. This precipitation can occur in and around pipes as flowback water comes back to the surface. This accumulation of minerals in pipes and other equipment is called scale. Concentration can also occur if salts are purposely precipitated as a means of wastewater treatment. NORM that has not precipitated out, but remains dissolved in water would be transported to ground or surface waters in the event of a leak or spill.