What’s NORMal for Fracking? Estimating Total Radioactivity of Produced Fluids

Naturally occurring radioactive materials (NORM) found in liquid wastes from hydraulic fracturing are an emerging environmental health concern. The heavily drilled Marcellus Shale, for example, contains isotopes of radium, polonium, and lead. However, the few studies that have focused on NORM in fracking wastewater (produced fluids) have reported on a single element—radium. In this issue of EHP, researchers estimate total reactivity for a mixture of isotopes present in liquid fracking waste from the Marcellus Shale. Decay chains—the series of transformations that radionuclides undergo until a stable isotope is produced—are important in planning for the treatment, management, and disposal of radioactive waste. Longlived radioactive elements (such as 226radium) transform into shorterlived decay products (such as 210lead and 210polonium). Some decay products approach the same radioactivity concentration as the parent radionuclide in a matter of days, while others do so over many decades.