[2] In addition, fracking releases naturally occurring heavy metals and radioactive materials from shale deposits, and these substances return to the surface with flowback, also referred to as wastewater.
[4] Hydraulic fracturing can dislodge naturally occurring heavy metals and radioactive materials from shale deposits, and these substances return to the surface with flowback, also referred to as wastewater or brine.
[5] Higher levels of Lead-210, the decay product of Radon-222, have been found on the airborne particulate matters that are collected downwind of wells completed with hydraulic fracturing.
[13] The NRC guidelines also list a wide range or radioactive materials in solid, liquid and gaseous forms that are used as field flood or enhanced oil and gas recovery study applications tracers used in single and multiple wells.
[10][11][12][13][15] Concerns have been expressed that both naturally occurring radionuclides and radioactive tracers may return to the surface with flowback and during blow outs.
[20] The New York Times has reported on radium and gross alpha radiation levels in wastewater (also called flowback) from natural gas wells.
When Iodine-131 is present in high levels in the environment from hydraulic fracturing flowback and blowouts, it can be absorbed through contaminated food and water, and will also accumulate in the thyroid.
[13] Federal and state regulators do not require sewage treatment plants that accept drilling waste to test for radioactivity.
[35] The EPA has asked the Pennsylvania Department of Environmental Protection to require community water systems in certain locations, and centralized wastewater treatment facilities to conduct testing for radionuclides.
[38] Radioactive tracers are not yet listed on FracFocus,[39] a website indicating chemical composition of fracking fluid of individual wells, but federal and state nuclear regulatory agencies keep records of their use.